Interlayer for laminated glass, laminate, and optical laminate

Abstract

To provide an interlayer for laminated glass that can suppress reductions in transmittance and adhesive strength caused by a low-temperature autoclave process, a laminate containing the interlayer for laminated glass, and an optical laminate including the interlayer for laminated glass or the laminate.SOLUTION: The present invention provides an interlayer for laminated glass having a single-layer structure or a multilayer structure, the interlayer including at least a thermoplastic resin layer (A) containing a thermoplastic resin, wherein, when the interlayer for laminated glass has a multilayer structure, at least one outermost layer is the thermoplastic resin layer (A), and, in a predetermined preliminary adhesion strength test, an average value of adhesive strength of all samples is 20 N or more. A laminate 50 of the present invention includes the interlayer for laminated glass 10 of the present invention and a functional layer 40 different from the interlayer for laminated glass 10. An optical laminate 1B of the present invention includes a first transparent substrate 20, a second transparent substrate 30, and the interlayer for laminated glass 10 of the present invention or the laminate 50 of the present invention.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an interlayer film for laminated glass, a laminate including the interlayer film for laminated glass, and an optical laminate including the interlayer film for laminated glass or the laminate. [Background technology]

[0002] Laminated glass, which is made by sandwiching an interlayer between two glass sheets and integrating them, has been widely known. The interlayer is often made of plasticized polyvinyl acetal, which is a polyvinyl acetal resin blended with a plasticizer. Laminated glass is safe because it rarely shatters into glass fragments even if it is broken by external impact, and is therefore widely used as window glass in vehicles such as automobiles, aircraft, buildings, etc.

[0003] Laminated glass is generally produced by placing two glass sheets with an interlayer film, and after a preliminary degassing process, heating and pressurizing the glass and interlayer film in an autoclave (ACV) process at a temperature of about 130 to 140°C and a pressure of about 1.3 MPa. Furthermore, various studies and improvements have been made on laminated glass interlayers for gas insulation, and Patent Document 1 discloses a laminated glass interlayer that exhibits a certain range of thickness change when subjected to a compression creep test.

[0004] In recent years, laminated glass has been required to have various functions, for example, a functional film such as a photochromic film may be disposed between two glass sheets. When a functional film such as a photochromic film is incorporated into laminated glass, it is known that an interlayer film is disposed between the functional film and each glass sheet, and the two glass sheets and the functional film are integrated via the interlayer film (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2021 / 117596 [Patent Document 2] International Publication No. 2019 / 066042 Summary of the Invention [Problem to be solved by the invention]

[0006] However, functional films such as photochromic elements are sensitive to heat, and when a glass plate, an interlayer film, and a functional film are pressure-bonded in an autoclave under conventional high-temperature, high-pressure conditions, the functional film is often deactivated. Another problem is the need to heat to a high temperature, which results in a large amount of carbon dioxide emissions. On the other hand, when pressure-bonding is performed in an autoclave at a low temperature, air may remain between the interlayer film and the glass plate or between the interlayer film and the functional film during pressure-bonding, which may result in poor transparency of the laminated glass obtained by pressure-bonding. Furthermore, when pressure-bonding is performed in an autoclave at a low temperature, the adhesive strength between the interlayer film and the glass plate may be insufficient.

[0007] Therefore, an object of the present invention is to provide an interlayer film for laminated glass that can suppress the decrease in transmittance and decrease in adhesive strength that occur during an autoclave process under low-temperature conditions, a laminate including the interlayer film for laminated glass, and an optical laminate including the interlayer film for laminated glass or the laminate. [Means for solving the problem]

[0008] After extensive research, the present inventors investigated pre-bonding, which is performed before a low-temperature autoclave process, and found that it is necessary to improve the adhesion between the interlayer film for laminated glass and the glass sheet during pre-bonding so that no air remains between the interlayer film for laminated glass and the glass sheet. Based on this finding, the present inventors discovered that the above-mentioned problems can be solved by using an interlayer film for laminated glass whose adhesion strength measured in a predetermined pre-bonding test is equal to or greater than a predetermined value, and completed the present invention as described below. Specifically, the present invention provides the following [1] to [9].

[0009] [1] An interlayer film for laminated glass having a single-layer structure or a multi-layer structure, At least a thermoplastic resin layer (A) containing a thermoplastic resin, When the interlayer film for laminated glass has a multilayer structure, at least one outermost layer is the thermoplastic resin layer (A), An interlayer film for laminated glass with an average adhesive strength of 20N or more for all samples in a preliminary adhesive strength test conducted under the following conditions: (Preliminary adhesive strength test conditions) Two 30 cm × 30 cm glass plates, a 30 cm × 42 cm highly adhesive PET film having high adhesiveness on one side, a 30 cm × 15 to 17 cm ultra-thin PET film, and a 30 cm × 30 cm interlayer film for laminated glass are prepared. They are arranged so that the highly adhesive side of the highly adhesive PET film is in contact with the interlayer film for laminated glass, and so that the thermoplastic resin layer (A) of the interlayer film for laminated glass is in contact with the glass plates and the ultra-thin PET film. The two glass plates, the adhesive PET film, the ultra-thin PET film, and the interlayer film for laminated glass are laminated together so that the structure is glass plate / adhesive PET film / interlayer film for laminated glass / glass plate within a distance of 20 cm from the longitudinal end of the adhesive PET film, and the structure is glass plate / adhesive PET film / interlayer film for laminated glass / thin PET film / glass plate within a distance of 20 cm from the longitudinal end of the adhesive PET film to a distance of 30 cm from the longitudinal end of the adhesive PET film. The laminated structure is formed so that the tin side of the glass contacts the interlayer film for laminated glass. The laminate is then vacuumed at room temperature for 5 minutes at an absolute pressure of 0.09 MPa. The temperature is then increased to 90°C at a rate of 6°C / min, and after reaching 90°C, it is cooled to room temperature. The glass plate that had been in contact with the adhesive PET film was then peeled from the adhesive PET film, and the laminated film of the adhesive PET film and the interlayer film for laminated glass was cut along the longitudinal direction of the adhesive PET film so that the width was 25 mm, producing 12 samples for peel tests each 25 mm wide and bonded to the glass. Each sample was then subjected to a 180° peel test in which the sample was peeled from the glass plate along the longitudinal direction at a peel rate of 300 mm / min. The adhesive strength of the sample was determined by the average adhesive strength between 20 and 180 mm of displacement, with the displacement at the point where the sample began to peel from the glass plate being defined as 0 mm. [2] The interlayer film for laminated glass according to claim 1, wherein, in the preliminary adhesion test, the lowest lower limit of the adhesive strength of all samples in the preliminary adhesion test is 12 N or more, when the lower limit of the adhesive strength between 20 and 180 mm is defined as the lower limit of the adhesive strength of the sample, with the displacement at the point where the sample begins to peel from the glass plate being 0 mm. [3] The interlayer film for laminated glass according to [1] or [2] above, which contains a colorant. [4] The interlayer film for laminated glass according to any one of the above [1] to [3], wherein the thermoplastic resin layer (A) contains a polyvinyl acetal resin and a plasticizer. [5] The interlayer film for laminated glass according to the above [4], wherein the content of the plasticizer is 30 to 55 parts by mass per 100 parts by mass of the polyvinyl acetal resin. [6] The interlayer film for laminated glass according to the above [4] or [5], wherein the plasticizer is at least one plasticizer selected from the group consisting of organic ester plasticizers and organic ether plasticizers. [7] A laminate comprising the interlayer film for laminated glass according to any one of [1] to [6] above, and a functional layer different from the interlayer film for laminated glass. [8] An optical laminate comprising a first transparent substrate, a second transparent substrate, and the interlayer film for laminated glass according to any one of [1] to [6] above, which is disposed between the first and second transparent substrates. [9] An optical laminate comprising a first transparent substrate, a second transparent substrate, and the laminate according to [7] above, disposed between the first and second transparent substrates. [Effects of the Invention]

[0010] The present invention can provide an interlayer film for laminated glass that can suppress the decrease in transmittance and decrease in adhesive strength that occur during an autoclave process under low-temperature conditions, a laminate including the interlayer film for laminated glass, and an optical laminate including the interlayer film for laminated glass or the laminate. [Brief explanation of the drawings]

[0011] [Figure 1]FIG. 1 is a diagram showing the layer structure of an optical laminate according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing the layer structure of an optical laminate according to a second embodiment of the present invention. [Figure 3] FIG. 3 is a diagram for explaining the preliminary adhesive strength test. [Figure 4] FIG. 4 is a diagram for explaining the preliminary adhesive strength test. [Figure 5] FIG. 5 is a diagram for explaining the preliminary adhesive strength test. [Figure 6] FIG. 6 is a diagram for explaining the preliminary adhesive strength test. DETAILED DESCRIPTION OF THE INVENTION

[0012] <Interlayer film for laminated glass> The interlayer film for laminated glass of the present invention is a thermoplastic resin film having a single-layer or multilayer structure, and includes at least a thermoplastic resin layer (A) containing a thermoplastic resin, and when the thermoplastic resin film has a multilayer structure, at least one outermost layer is the thermoplastic resin layer (A). The interlayer film for laminated glass of the present invention has an average adhesive strength of 20 N or more for all samples in a preliminary adhesive strength test carried out under the following conditions:

[0013] (Preliminary adhesive strength test conditions) Two 30 cm x 30 cm glass plates, a 30 cm x 42 cm adhesive PET film with adhesive properties on one side, a 30 cm x 15-17 cm ultra-thin PET film, and a 30 cm x 30 cm interlayer film for laminated glass were prepared. Next, the two glass plates, the adhesive PET film, the ultra-thin PET film, and the interlayer film for laminated glass were laminated together. The adhesive side of the adhesive PET film was laminated so that it was in contact with the interlayer film for laminated glass, and the thermoplastic resin layer (A) of the interlayer film for laminated glass was in contact with the glass plate. The structure was glass plate / adhesive PET film / interlayer film for laminated glass / glass plate within a 20 cm distance from the longitudinal end of the adhesive PET film. Furthermore, in the area from a position 20 cm away from the longitudinal end of the adhesive PET film to a position 30 cm away from the longitudinal end of the adhesive PET film, the laminated glass interlayer film was laminated to form a glass plate / adhesive PET film / interlayer film for laminated glass / thin-film PET film / glass plate configuration. A vacuum was then applied at room temperature for 5 minutes at an absolute pressure of 0.09 MPa. The temperature was then raised to 90°C at a heating rate of 6°C / min. After reaching 90°C, the laminated glass interlayer film was cooled to room temperature. The glass plate that had been in contact with the adhesive PET film was then peeled off from the adhesive PET film. The laminated film of the adhesive PET film and the interlayer film for laminated glass was then cut along the longitudinal direction of the adhesive PET film to a width of 25 mm, producing 12 samples for peel tests, each 25 mm wide and bonded to glass. Each sample was then subjected to a 180° peel test, in which the sample was peeled off from the glass plate along the longitudinal direction at a peel rate of 300 mm / min. At this time, the displacement at the point where the sample begins to peel off the glass plate is taken as 0 mm, and the average value of the adhesive strength between 20 and 180 mm of displacement is taken as the adhesive strength of the sample.

[0014] In the preliminary adhesion test of the present invention, an ultra-thin PET film is placed on only a portion of the upper surface of one of the glass plates, and the adhesive surface between the interlayer film for laminated glass and one of the glass plates after preliminary adhesion can be peeled off in a 180° peel test, which can be said to correspond to the adhesive strength between the glass plates and the interlayer film for laminated glass in preliminary adhesion. Therefore, if the average adhesive strength is less than 20 N, in cases where a functional layer is provided, the transparent substrate and the interlayer film for laminated glass may not be sufficiently bonded by pre-adhesion, and when laminated glass is produced by an autoclave process under low-temperature conditions, air may remain, reducing transmittance and reducing adhesive strength. From this perspective, the average adhesive strength of the interlayer film for laminated glass of the present invention is preferably 23 N or more, and more preferably 25 N or more. The upper limit of the range of the average adhesive strength of the interlayer film for laminated glass of the present invention is not particularly limited, but is usually 40 N.

[0015] The average adhesive strength in the preliminary adhesive strength test of the interlayer film for laminated glass can be adjusted, for example, by the type of resin contained in the thermoplastic resin layer (A) or by embossing the surface. It can also be adjusted by the amount and type of plasticizer contained in the thermoplastic resin layer (A). Furthermore, when a polyvinyl acetal resin is used, it can also be adjusted by the manufacturing conditions used to produce the polyvinyl acetal resin. Specifically, as described below, the average adhesive strength in the preliminary adhesive strength test of the interlayer film for laminated glass can be adjusted by the aging temperature in the aging step performed in the production of the polyvinyl acetal resin.

[0016] In the preliminary adhesion test, the displacement at the point where the sample begins to peel from the glass is defined as 0 mm, and the lower limit of the adhesive strength between 20 and 180 mm is defined as the lower limit of the adhesive strength of that sample. In the preliminary adhesion test of the interlayer film for laminated glass, the minimum lower limit of the adhesive strength of all samples is preferably 12 N or more. If the minimum lower limit of the adhesive strength of the interlayer film for laminated glass in the preliminary adhesion test is 13 N or more, the decrease in transmittance and adhesive strength that occurs during the autoclave process under low-temperature conditions can be further suppressed. From this perspective, the minimum lower limit of the adhesive strength of the interlayer film for laminated glass of the present invention is more preferably 14 N or more, and even more preferably 15 N or more. The range of the minimum lower limit of the adhesive strength of the interlayer film for laminated glass of the present invention is not particularly limited, but is typically 25 N or less. The minimum lower limit of the adhesive strength in the preliminary adhesion test of the interlayer film for laminated glass can be adjusted, for example, by the type of resin contained in the thermoplastic resin layer (A) and the type of embossing on the surface. It can also be adjusted by the amount and type of plasticizer contained in the thermoplastic resin layer (A). Furthermore, when a polyvinyl acetal resin is used, it can also be adjusted by the production conditions when producing the polyvinyl acetal resin. Specifically, as described below, the minimum value of the lower limit of the adhesive strength in a preliminary adhesive strength test of an interlayer film for laminated glass can be adjusted by the aging temperature in the aging step performed when producing the polyvinyl acetal resin.

[0017] Examples of the thermoplastic resin (a) used in the thermoplastic resin layer (A) of the present invention include (meth)acrylic resins, polyvinyl acetal resins, polyvinyl alcohol resins (PVA), 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, styrene-butadiene copolymer resins, etc. The thermoplastic resins may be used alone or in combination of two or more.

[0018] Among the above, from the viewpoint of achieving both moist heat resistance and impact resistance, the thermoplastic resin (a) is preferably a polyvinyl acetal resin, a polyurethane resin (PU), an ethylene-vinyl acetate copolymer resin (EVA), a saponified ethylene-vinyl acetate copolymer (EVOH), an ethylene-methacrylic acid copolymer resin, an ionomer resin, an isobutylene resin, a styrene-isoprene copolymer resin, or a styrene-butadiene copolymer resin. Furthermore, among the above, the thermoplastic resin is more preferably a polyvinyl acetal resin. The use of a polyvinyl acetal resin facilitates achieving excellent impact resistance. It also facilitates achieving good adhesion to various resin materials and inorganic glass. The polyvinyl acetal resin used in the thermoplastic resin (a) will be described in detail below.

[0019] (Polyvinyl acetal resin) The polyvinyl acetal resin is not particularly limited as long as it is a polyvinyl acetal resin obtained by acetalizing polyvinyl alcohol (PVA) with an aldehyde. The aldehyde is not particularly limited, but generally, an aldehyde having 1 to 10 carbon atoms is suitably used. The aldehyde having 1 to 10 carbon atoms is not particularly limited, and examples thereof include n-butylaldehyde, isobutyraldehyde, n-valeraldehyde, 2-ethylbutyraldehyde, n-hexylaldehyde, n-octylaldehyde, n-nonylaldehyde, n-decylaldehyde, formaldehyde, acetaldehyde, benzaldehyde, etc. These aldehydes may be used alone or in combination of two or more. Among the above, n-butylaldehyde, n-hexylaldehyde, and n-valeraldehyde are preferred, and n-butylaldehyde is more preferred. Therefore, the polyvinyl acetal resin is preferably a polyvinyl butyral resin.

[0020] Polyvinyl alcohol (PVA) can be obtained by saponifying a polyvinyl ester such as polyvinyl acetate, etc. The degree of saponification of polyvinyl alcohol is generally 70 to 99.9 mol %. The average degree of polymerization of PVA is preferably 200 or more, more preferably 500 or more, even more preferably 750 or more, and even more preferably 1200 or more. When the average degree of polymerization is equal to or more than the above lower limit, the penetration resistance of the optical laminate when used in the optical laminate is increased. Furthermore, the average degree of polymerization of PVA is preferably 5000 or less, more preferably 3500 or less, even more preferably 3000 or less, and even more preferably 2000 or less. The average degree of polymerization of polyvinyl alcohol is determined by a method conforming to JIS K6726 "Testing Method for Polyvinyl Alcohol." When two or more types of polyvinyl alcohol are used as raw materials, the average degree of polymerization of the polyvinyl alcohol can be estimated by calculation from the average degrees of polymerization of each polyvinyl alcohol.

[0021] Two or more polyvinyl alcohols having different average degrees of polymerization may be used as the polyvinyl alcohol raw material for the polyvinyl acetal resin. In this case, it is preferable to use a mixture of two or more polyvinyl alcohols as the raw material to produce the polyvinyl acetal resin by the production method described below. When two or more types of polyvinyl alcohols are used, it is preferable to use, for example, a first polyvinyl alcohol having an average degree of polymerization of 1500 or more and a second polyvinyl alcohol having an average degree of polymerization of 1200 or less. The average degree of polymerization of the first polyvinyl alcohol is preferably 1500 or more and 3500 or less, more preferably 1600 or more and 2500 or less, and even more preferably 1600 or more and 2000 or less. The average degree of polymerization of the second polyvinyl alcohol is preferably 200 or more and 1200 or less, more preferably 300 or more and 900 or less, and even more preferably 400 or more and 850 or less. When the first and second polyvinyl alcohols are used, the blending ratio of the first polyvinyl alcohol to the second polyvinyl alcohol is not particularly limited, but the blending amount of the second polyvinyl alcohol relative to the total amount of the first and second polyvinyl alcohols is preferably 1% by mass or more and 50% by mass or less, more preferably 3% by mass or more and 40% by mass or less, even more preferably 5% by mass or more and 35% by mass or less, and still more preferably 10% by mass or more and 30% by mass or less.

[0022] The amount of hydroxyl groups in the polyvinyl acetal resin is preferably 15 mol% or more, and preferably 38 mol% or less. By setting the amount of hydroxyl groups to 15 mol% or more, good adhesion is likely to be achieved, and when used in an optical laminate, the penetration resistance and other properties of the optical laminate are likely to be good. Furthermore, by setting the amount of hydroxyl groups to 38 mol% or less, flexibility is easily ensured, preventing the optical laminate from becoming too hard. Furthermore, by adjusting the amount of hydroxyl groups within the above range, the generation of bubbles due to use in a high-temperature environment can be further suppressed, and the high-temperature heat resistance of the interlayer film for laminated glass can be further improved. The amount of hydroxyl groups is more preferably 20 mol % or more, and even more preferably 25 mol % or more, and more preferably 35 mol % or less, and even more preferably 33 mol % or less. When a polyvinyl butyral resin is used as the polyvinyl acetal resin, from the same viewpoint, the amount of hydroxyl groups is 15 mol% or more, and preferably 38 mol% or less, more preferably 20 mol% or more, even more preferably 25 mol% or more, more preferably 35 mol% or less, and even more preferably 33 mol% or less. The amount of hydroxyl groups in a polyvinyl acetal resin is the molar fraction calculated by dividing the amount of ethylene groups having hydroxyl groups by the total amount of ethylene groups in the main chain, and is expressed as a percentage. The amount of ethylene groups having hydroxyl groups can be measured, for example, in accordance with JIS K6728 "Testing Methods for Polyvinyl Butyral."

[0023] The degree of acetalization of the polyvinyl acetal resin is preferably 47 mol% or more and preferably 85 mol% or less, more preferably 55 mol% or more, even more preferably 60 mol% or more, and more preferably 80 mol% or less, even more preferably 75 mol% or less. The degree of acetalization means the degree of butyralization when the acetal group is a butyral group and the polyvinyl acetal resin (A) is a polyvinyl butyral resin.

[0024] The degree of acetalization is a molar fraction calculated by subtracting the amount of ethylene groups having hydroxyl groups and the amount of ethylene groups having acetyl groups from the total amount of ethylene groups in the main chain, and dividing the result by the total amount of ethylene groups in the main chain. The degree of acetalization (degree of butyralization) may be calculated from the results of measurements in accordance with, for example, JIS K6728 "Testing Methods for Polyvinyl Butyral."

[0025] The acetylation degree of the polyvinyl acetal resin is preferably 30 mol% or less, more preferably 20 mol% or less, even more preferably 10 mol% or less, and even more preferably 2 mol% or less. When the acetylation degree is equal to or less than the upper limit, the moisture resistance of the polymer film is improved. Furthermore, the acetylation degree is not particularly limited, but is preferably 0.01 mol% or more, and more preferably 0.1 mol% or more. The degree of acetylation is a molar fraction calculated by dividing the amount of ethylene groups having acetyl groups by the total amount of ethylene groups in the main chain, and is expressed as a percentage. The amount of ethylene groups having acetyl groups can be measured, for example, in accordance with JIS K6728 "Testing Methods for Polyvinyl Butyral."

[0026] The polyvinyl acetal resin is preferably an unmodified polyvinyl acetal resin, but may also be a modified polyvinyl acetal resin. The modified polyvinyl acetal resin has a structure (modifying group) other than an acetal group, a hydroxyl group, and an acetyl group, and preferably has a modifying group in a side chain. Examples of the modifying group include those having a polyalkylene oxide structure in the side chain, and those having an alkyl group (e.g., having about 2 to 30 carbon atoms) other than an acetal group or an acetyl group in the side chain. The modification amount is not particularly limited, but is, for example, about 0.1 mol % to 10 mol %. The modification amount represents the ratio of functional groups to all vinyl monomer units constituting the polyvinyl acetal resin. In the thermoplastic resin layer (A), the polyvinyl acetal resin may be used alone or in combination of two or more kinds.

[0027] When a polyvinyl acetal resin is used as the thermoplastic resin (a) in the thermoplastic resin layer (A), the layer (A) may contain a thermoplastic resin other than the polyvinyl acetal resin, as long as the effects of the present invention are achieved. The thermoplastic resin other than the polyvinyl acetal resin is as described above. However, it is preferable that the thermoplastic resin layer (A) contains a polyvinyl acetal resin as the main component. Specifically, the content of the polyvinyl acetal resin is, for example, 50% by mass or more, preferably 70% by mass or more, more preferably 90% by mass or more, and most preferably 100% by mass, based on the total amount of the thermoplastic resin (a) contained in the thermoplastic resin layer (A). Therefore, the thermoplastic resin (a) contained in the thermoplastic resin layer (A) of the present invention may consist solely of a polyvinyl acetal resin.

[0028] (Method for producing polyvinyl acetal resin) The polyvinyl acetal resin is preferably produced by a production method including a mixing step of mixing the polyvinyl alcohol and the aldehyde, and an aging step of aging the mixture obtained in the mixing step.

[0029] In the mixing step, polyvinyl alcohol and aldehyde may be mixed according to a conventional method. In addition to polyvinyl alcohol and aldehyde, a catalyst such as an acid catalyst may be added to promote the acetalization reaction. For example, the aldehyde may be added to a mixture of polyvinyl alcohol and an acid catalyst at a low temperature of about 0 to 40°C. When two or more polyvinyl alcohols are used in combination (for example, when two or more polyvinyl alcohols with different molecular weights are used), the two or more polyvinyl alcohols may be mixed with the aldehyde.

[0030] The aging step is not particularly limited, but may be carried out, for example, by adding a catalyst such as an acid catalyst to the mixture (reaction mixture) obtained by the mixing step, heating the mixture to a aging temperature, and maintaining the mixture at the aging temperature for a certain period of time. In this production method, acetalization of polyvinyl alcohol proceeds in the mixing step and the aging step, thereby producing a polyvinyl acetal resin. The reaction mixture is maintained at the aging temperature for a certain period of time, and then cooled appropriately and neutralized, and may then be washed with water, dried, or the like, as necessary.

[0031] Examples of the acid catalyst added in the mixing step and the aging step include inorganic acids such as hydrochloric acid, nitric acid, phosphoric acid, boric acid, sulfuric acid, etc. In the aging step, the concentration of the acid catalyst is adjusted to, for example, about 0.5% by mass to 5% by mass, and preferably about 1% by mass to 2.5% by mass. The aging temperature in the aging step may be relatively low, for example, 40° C. to 60° C., preferably 35° C. to 60° C., and more preferably 40° C. to 57° C. The time for which the aging temperature is maintained (aging time) may be longer than a certain time, for example, 75 minutes to 180 minutes, preferably 90 minutes to 150 minutes, and more preferably 100 minutes to 140 minutes.

[0032] It is believed that setting the aging temperature and aging time within the desired ranges above facilitates uniform distribution of hydroxyl groups within the polyvinyl acetal resin molecules, thereby reducing the amount of low molecular weight components and narrowing the molecular weight distribution. As a result, the average adhesive strength in the preliminary adhesive strength test can be increased. Furthermore, the amount of low molecular weight components is reduced, making it easier to narrow the molecular weight distribution. While the reason for the reduction in low molecular weight components is unclear, it is believed to be due to the promotion of intermolecular crosslinking.

[0033] (plasticizer) The thermoplastic resin layer (A) preferably contains a plasticizer. The inclusion of a plasticizer makes the thermoplastic resin layer (A) flexible, which can improve the adhesion of the thermoplastic resin layer (A) to various adherends and the penetration resistance. In addition, the average adhesive strength in the above-mentioned preliminary adhesive strength test can be easily increased.

[0034] Examples of plasticizers include organic ester plasticizers, organic phosphorus-based plasticizers such as organic phosphate ester plasticizers and organic phosphite ester plasticizers, organic ether-based plasticizers such as polyalkylene glycol-based plasticizers, and alcohol-based plasticizers. The plasticizers may be used alone or in combination of two or more. Among the above, organic ester plasticizers and organic ether plasticizers are preferred.

[0035] Preferred organic ester plasticizers include monobasic organic acid esters and polybasic organic acid esters. Examples of monobasic organic acid esters include esters of glycols and monobasic organic acids. Examples of glycols include polyalkylene glycols in which each alkylene unit has 2 to 4 carbon atoms, preferably 2 or 3 carbon atoms, and the number of repeating alkylene units is 2 to 10, preferably 2 to 4. The glycol may also be a monoalkylene glycol having 2 to 4 carbon atoms, preferably 2 or 3 carbon atoms (i.e., one repeating unit). Specific examples of glycols include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, and butylene glycol. Examples of monobasic organic acids include organic acids having 3 to 10 carbon atoms, and specific examples thereof include butyric acid, isobutyric acid, caproic acid, 2-ethylbutyric acid, heptyl acid, n-octylic acid, 2-ethylhexyl acid, n-nonylic acid, and decylic acid.

[0036] Specific monobasic organic acid esters include triethylene glycol di-2-ethylbutyrate, triethylene glycol di-2-ethylhexanoate, triethylene glycol dicaprylate, triethylene glycol di-n-octanoate, triethylene glycol di-n-heptanoate, tetraethylene glycol di-n-heptanoate, tetraethylene glycol di-2-ethylhexanoate, diethylene glycol di-2-ethylbutyrate, diethylene glycol di-2-ethylhexanoate, dipropylene glycol di-2-ethylbutyrate, triethylene glycol Examples of suitable ethylene glycol di-2-ethylpentanoate include tetraethylene glycol di-2-ethylbutyrate, diethylene glycol dicaprylate, 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, and 1,2-butylene glycol di-2-ethylbutyrate.

[0037] Furthermore, examples of polybasic organic acid esters include ester compounds of dibasic organic acids having 4 to 12 carbon atoms, such as adipic acid, sebacic acid, and azelaic acid, with alcohols having 4 to 10 carbon atoms. The alcohols having 4 to 10 carbon atoms may be linear, have a branched structure, or have a cyclic structure. Specific examples include dibutyl sebacate, dioctyl azelaate, dihexyl adipate, dioctyl adipate, hexylcyclohexyl adipate, diisononyl adipate, heptylnonyl adipate, dibutyl carbitol adipate, and mixed adipates. Oil-modified alkyd sebacate is also acceptable. Examples of mixed adipates include adipates prepared from two or more alcohols selected from alkyl alcohols having 4 to 9 carbon atoms and cyclic alcohols having 4 to 9 carbon atoms.

[0038] The organic ester plasticizer is not limited to the complete esters of the above-mentioned esters, but may also be a partial ester. For example, it may be a partial ester of glycol and a monobasic organic acid, or a partial ester of a dibasic organic acid and an alcohol. Specific examples include triethylene glycol-mono-2-ethylhexanoate. Furthermore, it may be a partial ester of a monobasic organic acid with a trihydric or higher alcohol such as glycerin. Examples of the monobasic organic acid include monobasic organic acids having 3 to 24 carbon atoms, preferably 6 to 18 carbon atoms. Specific examples of the partial ester of a trihydric or higher alcohol with a monobasic organic acid include a mono- or diester of glycerin and stearic acid, and a mono- or diester of glycerin and 2-ethylhexyl acid. Of the organic ester plasticizers mentioned above, triethylene glycol-di-2-ethylhexanoate (3GO) is particularly preferably used.

[0039] Examples of the organic phosphorus plasticizer include phosphoric acid esters such as tributoxyethyl phosphate, isodecylphenyl phosphate, and triisopropyl phosphate. Examples of polyalkylene glycol plasticizers include polyoxyalkylene compounds having a polyoxyalkylene structure, specifically polyhydric alcohol compounds such as glycol, ester compounds of glycol with a monobasic organic acid or a polybasic organic acid, and ether compounds of a monohydric or polyhydric alcohol with a polyoxyalkylene. Examples of glycols include polyoxyalkylene glycols and their derivatives. Examples of polyoxyalkylenes include polyoxyethylene, polyoxypropylene, polyoxybutylene, and random or block copolymers thereof. The polyoxyalkylene compounds may be polyhydric alcohol compounds, ester compounds, ether compounds, or other compounds, as described above. Examples of polyoxyalkylene compounds include polyoxyalkylenes and derivatives thereof. More specifically, examples include polyoxyalkylene glycols composed of the above-mentioned polyoxyalkylenes, and ether compounds of polyoxyalkylenes and polyhydric alcohols. All of these compounds may have hydroxyl groups at their terminals, or may be derivatives in which some or all of the hydrogen atoms of the terminal hydroxyl groups have been substituted with alkyl groups or acyl groups. The number of carbon atoms in the alkyl and acyl groups is not particularly limited, but may be about 1 to 8, preferably 1 to 4. Examples of polyoxyalkylene glycols include polyoxyethylene polyoxypropylene glycols such as polyethylene glycol (polyoxyethylene glycol), polypropylene glycol (polyoxypropylene glycol), poly(ethylene oxide / propylene oxide) block copolymers and poly(ethylene oxide / propylene oxide) random copolymers, and polyoxybutylene glycols such as polytetramethylene glycol. Examples of ether compounds of polyoxyalkylenes and polyhydric alcohols include ether compounds of polyoxyalkylenes and polyhydric alcohols such as glycerol, diglycerol, trimethylolpropane, erythritol, pentaerythritol, and bisphenol A, specifically polyoxyethylene glyceryl ether, polyoxypropylene glyceryl ether, polyoxyethylene diglyceryl ether, polyoxypropylene diglyceryl ether, polyoxyalkylene pentaerythritol ether, etc. Examples of derivatives in which some or all of the hydrogen atoms of terminal hydroxyl groups have been substituted with alkyl groups or acyl groups include the above-mentioned polyoxyalkylene glycols and derivatives in which some or all of the hydrogen atoms of terminal hydroxyl groups of ether compounds have been substituted with alkyl groups or acyl groups. Specific examples include polyoxyethylene glycol monomethyl ether, polyoxyethylene glycol dimethyl ether, polyoxypropylene glycol monomethyl ether, polyoxypropylene glycol dimethyl ether, polyoxyethylene polyoxypropylene glycol monomethyl ether, polyoxyethylene polyoxypropylene glycol dimethyl ether, polyoxyethylene glycol monobutyl ether, polyoxypropylene glycol monobutyl ether, and polyoxyethylene polyoxypropylene monobutyl ether. Among the above-mentioned polyoxyalkylene compounds, those having a polyoxyethylene, polyoxypropylene, or polyoxyethylene polyoxypropylene structure are preferred, and among these, those having a polyoxypropylene or polyoxyethylene polyoxypropylene structure are more preferred. Specifically, polyoxyethylene polyoxypropylene glycol, polyoxypropylene glyceryl ether, polyoxypropylene diglyceryl ether, or derivatives thereof in which some of the hydrogen atoms of the terminal hydroxyl groups are substituted with alkyl groups are preferred. Examples of alcohol-based plasticizers include various polyhydric alcohols such as butanediol, hexanediol, trimethylolpropane, pentaerythritol, etc. Among these, trimethylolpropane is preferred. Examples of alcohol-based plasticizers include various polyhydric alcohols such as butanediol, hexanediol, trimethylolpropane, pentaerythritol, etc. Among these, trimethylolpropane is preferred.

[0040] The above plasticizers can be used alone or in combination of two or more. Among the above plasticizers, triethylene glycol-di-2-ethylhexanoate (3GO), polyoxypropylene diglyceryl ether (DGP) and polypropylene glycol (PPG) are preferred, and triethylene glycol-di-2-ethylhexanoate (3GO) is more preferred.

[0041] The content of the plasticizer in the thermoplastic resin layer (A) is not particularly limited, but is preferably 10 to 100 parts by mass per 100 parts by mass of the thermoplastic resin (a). When the content of the plasticizer is 10 parts by mass or more, the thermoplastic resin layer (A) becomes moderately flexible, improving the adhesiveness of the thermoplastic resin layer (A) and the penetration resistance of the optical laminate. Furthermore, it becomes easier to increase the average adhesive strength in the preliminary adhesive strength test described above. On the other hand, when the content of the plasticizer is 100 parts by mass or less, separation of the plasticizer from the thermoplastic resin layer (A) is prevented. The above content of plasticizer is more preferably 15 parts by mass or more, even more preferably 30 parts by mass or more, even more preferably 35 parts by mass or more, and more preferably 70 parts by mass or less, even more preferably 60 parts by mass or less, and even more preferably 50 parts by mass or less.

[0042] Furthermore, when the thermoplastic resin layer (A) contains a polyvinyl acetal resin, the content of the plasticizer in the thermoplastic resin layer (A) is preferably 30 to 50 parts by mass relative to 100 parts by mass of the polyvinyl acetal resin. When the content of the plasticizer is 30 parts by mass or more, the thermoplastic resin layer (A) becomes appropriately flexible, improving the adhesiveness of the thermoplastic resin layer (A) and the penetration resistance of the optical laminate. Furthermore, the average adhesive strength in the preliminary adhesive strength test described above also tends to be large. On the other hand, when the content of the plasticizer is 50 parts by mass or less, separation of the plasticizer from the thermoplastic resin layer (A) is prevented. The content of the plasticizer is more preferably 35 parts by mass or more, and more preferably 45 parts by mass or less, and even more preferably 42 parts by mass or less.

[0043] The thermoplastic resin layer (A) may contain, in addition to the plasticizer, any known additives that are used in combination with the thermoplastic resin (a). That is, the thermoplastic resin layer (A) may consist of a thermoplastic resin (a) such as a polyvinyl acetal resin, or a thermoplastic resin (a) and a plasticizer, but may also contain additives other than the plasticizer that are blended as necessary. Specific examples of additives other than plasticizers include ultraviolet absorbers, infrared absorbers, antioxidants, light stabilizers, adhesion modifiers, colorants, fluorescent brighteners, and crystal nucleating agents.

[0044] The thermoplastic resin layer (A) may contain a colorant as described above. By using the colorant, the interlayer film for laminated glass can be well colored to a desired color tone. The colorant may be used alone or in combination of two or more. The thermoplastic resin layer (A) may contain one or more colorants.

[0045] Examples of the colorant include pigments and dyes. The colorant may be a pigment, a dye, or both a pigment and a dye. Note that there are also colorants that are classified as both pigments and dyes.

[0046] Pigment: The colorant may contain a pigment, or may be a pigment itself. The thermoplastic resin layer (A) may contain a pigment, or may not contain a pigment. The pigment may be used alone, or two or more types may be used in combination, or three or more types may be used, or ten or fewer types may be used, or five or fewer types may be used. The thermoplastic resin layer (A) may contain a pigment alone, or two or more types, or three or more types, or ten or fewer types, or five or fewer types.

[0047] 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.

[0048] When the thermoplastic resin layer (A) contains a pigment, the content of the pigment in 100% by mass of the thermoplastic resin layer (A) is preferably 0.0001% by mass or more, more preferably 0.01% by mass or more, even more preferably 0.02% by mass or more, and preferably 0.15% by mass or less, more preferably 0.12% by mass or less.

[0049] dye: The colorant may contain a dye or may be a dye. The thermoplastic resin layer (A) may contain or may not contain a dye. The dye may be used alone, two or more kinds may be used in combination, three or more kinds, ten or less kinds, or five or less kinds.

[0050] 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, and azo compounds.

[0051] When the thermoplastic resin layer (A) contains a dye, the content of the dye in 100% by mass of the thermoplastic resin layer (A) is preferably 0.00001% by mass or more, more preferably 0.0001% by mass or more, even more preferably 0.001% by mass or more, preferably less than 0.015% by mass, and more preferably 0.01% by mass or less.

[0052] When the thermoplastic resin layer (A) contains a colorant, the content of the colorant in 100% by mass of the thermoplastic resin layer (A) is preferably 0.00001% by mass or more, more preferably 0.0001% by mass or more, even more preferably 0.001% by mass or more, and preferably 0.15% by mass or less, more preferably 0.12% by mass or less.

[0053] As described above, the interlayer film for laminated glass of the present invention has a single-layer structure or a multilayer structure. When the interlayer film for laminated glass of the present invention has a multilayer structure, some of the layers may be thermoplastic resin layers (A), or all of the layers may be thermoplastic resin layers (A). When the interlayer film for laminated glass has a multilayer structure, it is sufficient that either one of the outermost layers is a thermoplastic resin layer (A), but it is preferable that both outermost layers are thermoplastic resin layers (A). When both outer layers are thermoplastic resin layers (A), it is easier to further suppress residual air and peripheral foaming when pressure-bonding to a transparent substrate, etc. On the other hand, when it has a single-layer structure, the interlayer film for laminated glass preferably consists of a single layer of the above-mentioned thermoplastic resin layer (A).

[0054] When the interlayer film for laminated glass has a two-layer structure, for example, either one of the layers may be the thermoplastic resin layer (A), but it is preferable that both layers are thermoplastic resin layers (A). Furthermore, when the interlayer film for laminated glass has a three-layer structure having two outermost layers and a middle layer, it is sufficient that either one of the outermost layers is a thermoplastic resin layer (A), but it is preferable that both outermost layers are thermoplastic resin layers (A). In this case, the middle layer may be composed of a thermoplastic resin layer (A), but may also be composed of a resin other than the thermoplastic resin layer (A). The interlayer film for laminated glass may have two outermost layers and two or more intermediate layers, resulting in a four-layer or more structure. In this case, it is sufficient that either one of the outermost layers is a thermoplastic resin layer (A), but it is preferable that both are thermoplastic resin layers (A). Each intermediate layer may be composed of a thermoplastic resin layer (A), or may be composed of a material other than a thermoplastic resin layer (A). Furthermore, when the interlayer film for laminated glass of the present invention has multiple thermoplastic resin layers (A), the thermoplastic resin layers (A) may have the same configuration or different configurations. For example, the types and contents of the thermoplastic resins constituting the multiple thermoplastic resin layers (A) may be the same or different from one another. Furthermore, when the interlayer film for laminated glass has a layer other than the thermoplastic resin layer (A), such a layer may be, for example, a resin layer other than a thermoplastic resin layer.

[0055] In the interlayer film for laminated glass, the thickness of the thermoplastic resin layer (A) is not particularly limited, but it preferably accounts for a certain percentage or more of the total thickness of the interlayer film for laminated glass. Specifically, the thickness of the thermoplastic resin layer (A) may be, for example, a percentage of 0.1 to 1, preferably 0.3 to 1, more preferably 0.5 to 1, and even more preferably 0.75 to 1. Note that the thickness of the thermoplastic resin layer (A) here refers to the total thickness of two or more thermoplastic resin layers (A). When the thermoplastic resin layer (A) is contained in the interlayer film for laminated glass at a certain thickness percentage or more, it becomes easier to suppress residual air and peripheral foaming during pressure bonding.

[0056] The specific thickness of each thermoplastic resin layer (A) is not particularly limited, but is, for example, 10 μm or more and 2000 μm or less, preferably 20 μm or more and 1000 μm or less, and more preferably 30 μm or more and 900 μm or less. When the thermoplastic resin layer (A) has a certain thickness or more, it becomes easier to suppress the remaining air during pressure bonding. Furthermore, when the thickness is set to a certain thickness or less, it is possible to prevent the interlayer film for laminated glass from becoming thicker than necessary.

[0057] The interlayer film for laminated glass of the present invention preferably has an uneven shape on one or both surfaces. In this case, in the interlayer film for laminated glass of the present invention, the recesses of the uneven shape on at least one surface preferably have groove-like shapes with continuous bottoms to form score-like recesses. When pre-bonding is performed using a rubber backing, the edges are temporarily bonded first, which can make it difficult for air to escape from near the center. However, by forming score-like recesses, air can also easily escape from near the center, improving adhesion during pre-bonding. It is more preferable that a plurality of the score-shaped recesses are arranged in parallel, and it is even more preferable that adjacent recesses are arranged in a regular, parallel arrangement. Generally, the ease with which air escapes when a laminate in which an interlayer film for laminated glass is laminated between two glass plates is pressure-bonded is closely related to the interconnectedness and smoothness of the bottoms of the recesses. By forming the irregularities on at least one surface of the interlayer film in a shape in which score-shaped recesses are arranged in parallel and in a regular, parallel arrangement, the interconnectedness of the bottoms is excellent, and deaeration properties are further improved. In addition, it is preferable that adjacent ruled recesses arranged in parallel at equal intervals are parallel to each other, but the intervals between all adjacent ruled recesses do not have to be equal. Furthermore, the ruled recesses do not have to have a continuous groove shape at the entire bottom, and may have a dividing wall at part of the bottom. Furthermore, as long as adjacent recesses are arranged in parallel at regular intervals, the shape of the groove at the bottom does not have to be linear, and may be, for example, wavy or zigzag.

[0058] When the interlayer film for laminated glass of the present invention has an uneven surface, the surface roughness (R zjis94 The surface roughness (R zjis94 From this viewpoint, the surface roughness (R zjis94 ) is more preferably 20 to 65 μm, and further preferably 20 to 50 μm. zjis94) can be measured in accordance with JIS B-0601 (1994). When the surface has a scribed-line texture, the measurement can be performed in a direction perpendicular to the direction in which the scribed-line depressions are continuous. A measuring instrument such as the "Surfcorder SE300" manufactured by Kosaka Laboratory Co., Ltd. can be used. Measurements can be performed under the following conditions: a cutoff value of 2.5 mm, a reference length of 2.5 mm, a measurement length of 12.5 mm, a preliminary length of 2.5 mm, a palpation needle feed rate of 0.5 mm / sec, and a palpation needle with a tip radius of 2 μm and a tip angle of 60°. The measurement is performed in an environment of 23°C and 30% RH. The interlayer film to be measured is allowed to stand in the measurement environment for at least 3 hours before measurement.

[0059] The method for producing the interlayer film for laminated glass is not particularly limited, and it may be produced by a conventionally known method such as extrusion molding or press molding, but production by extrusion molding is preferred. Methods for forming a large number of recesses and a large number of protrusions on at least one surface of the interlayer film for laminated glass include, for example, an embossing roll method, a calendar roll method, a profile extrusion method, a melt fracture method, etc. Among these, the embossing roll method is preferred.

[0060] [Laminate] The laminate of the present invention includes the interlayer film for laminated glass of the present invention and a functional layer different from the interlayer film for laminated glass of the present invention. By including the interlayer film for laminated glass, the laminate of the present invention can utilize pressure bonding in an autoclave at low temperatures when incorporating the functional layer into an optical laminate or the like, thereby preventing the functional layer from being deactivated. In the laminate of the present invention, the functional layer is preferably disposed between a pair of interlayer films for laminated glass of the present invention. However, the functional layer may also be disposed between the interlayer film for laminated glass of the present invention and an interlayer film for laminated glass other than the interlayer film for laminated glass of the present invention described above. Furthermore, the layer configuration of the laminate is not limited to a configuration in which the functional layer is disposed between a pair of interlayer films for laminated glass, and various embodiments can be adopted, as described below.

[0061] [Feature Layer] The functional layer used in the laminate of the present invention is not particularly limited as long as it has a predetermined function. For example, a functional film can be used as the functional layer used in the laminate of the present invention. The functional film may be a light control film, a display element film, or an optical film such as a polarizing film, a retardation film, or an anti-reflection film. A solar cell element can also be used as the functional layer.

[0062] Furthermore, among the above, the functional film is preferably a film equipped with electronic components, such as a light control film or a display element film. Films equipped with electronic components are prone to deterioration or inactivation of their functions when autoclaved under high-temperature and high-pressure conditions. However, according to the present invention, the film can be pressure-bonded by autoclaving at a low temperature, so that a functional layer, such as an optical laminate, can be incorporated without inactivating the functional layer. Therefore, even a film equipped with electronic components can be incorporated into a laminate for practical use. Furthermore, when an optical laminate having either a light control film or a display element film is incorporated into various types of window glass, window glass with high added value can be provided, so in the present invention, it is desirable to use any of these functional films as the functional layer.

[0063] The light control film is a film-like component having a light control element. Specifically, the light control element is preferably a light control film comprising two resin films and a light control layer disposed between the two resin films. Therefore, the adhesive surface of the light control film with the thermoplastic resin layer is made of a resin material, which tends to increase the adhesive strength to the thermoplastic resin layer (A). Resin films used in light control elements are not particularly limited, but examples include polyester resin films such as PET film and PEN film, (meth)acrylic resin films, TAC film, PES resin film, and polyimide resin films. Among these, polyester resin films are preferred from the viewpoint of ease of handling, and PET film is more preferred. Furthermore, each of the two resin films has a conductive layer forming an electrode on the surface facing the light control layer.

[0064] The light-controlling layer changes its visible light transmittance by switching between applying and not applying a voltage between the conductive layers of two resin films. The light-controlling layer is composed of a liquid crystal layer such as a polymer-dispersed liquid crystal (PDLC), and the light-controlling film may be a PDLC film. The light-controlling film may also be an SPD (Suspended Particle Device) film, an electrochromic film, an electrophoretic film device, or the like. Therefore, the light-controlling layer may be an SPD layer containing a resin matrix and a light-controlling suspension dispersed in the resin matrix, or an electrochromic material layer. Alternatively, the light-controlling layer may be an electrophoretic layer containing electrophoretic particles and a dispersant for dispersing the electrophoretic particles.

[0065] The display element film is a film-like member including a display element. Examples of the display element film include a resin film and a display element mounted on the resin film. The display element film may be a pair of resin films with a display element provided therebetween. With this configuration, when the display element film is disposed between a pair of interlayer films for laminated glass and incorporated into an optical laminate, it can be adhered to the interlayer films for laminated glass with high adhesiveness. The resin film used for the display element film can be appropriately selected from the resin films listed for the light control film. In addition, in the display element film, a conductive layer that forms an electrode may be provided on the surface of the resin film facing the display element. Examples of the display element include an organic EL element, an LED display, and a segment display, and among these, an organic EL element is preferred.

[0066] The functional film having electronic components is not limited to the above-mentioned display element film and light control film, but may be other functional films. The electronic components may be mounted on a resin film in the same manner as the display element film and light control film, but a preferred embodiment is one in which the electronic components are arranged between a pair of resin films.

[0067] By using a solar cell element in the functional layer, it is possible to provide laminated glass for building-integrated photovoltaics (BIPV). The solar cell element is not particularly limited as long as it is a solar cell element used in building-integrated power generation systems (BIPV), and examples thereof include solar cell elements such as crystalline or thin-film silicon solar cell elements; compound semiconductor solar cell elements such as CIS, CIGS, CdTe, and GaAs; and organic solar cell elements such as dye-sensitized, organic thin-film, and perovskite solar cell elements.

[0068] The laminate can be produced by, for example, thermocompression bonding the functional layer and the interlayer film for laminated glass. When incorporating the laminate into an optical laminate, the thermocompression bonding may be performed by first thermocompression bonding the functional layer and the interlayer film for laminated glass to form a laminate, and then compressing the laminate to a transparent substrate to form the optical laminate. Alternatively, the functional layer and the interlayer film may be compressed together in the process of compressing the transparent substrate and the interlayer film for laminated glass, with the functional layer and the interlayer film being disposed between the transparent substrate before compression bonding.

[0069] [Optical laminate] The optical laminate of the present invention comprises a first transparent substrate, a second transparent substrate, and the interlayer film for laminated glass of the present invention or the laminate of the present invention disposed between the first and second transparent substrates.

[0070] [First and second transparent substrates] The first and second transparent substrates used in the optical laminate of the present invention may be, for example, glass plates. The glass plates may be either inorganic glass or organic glass, but inorganic glass is preferred. Examples of inorganic glass include, but are not limited to, clear glass, float glass, tempered glass, colored glass, polished glass, patterned glass, wired glass, lined glass, ultraviolet-absorbing glass, infrared-reflecting glass, infrared-absorbing glass, and green glass. Furthermore, the organic glass generally used is what is called resin glass, and examples thereof include various organic glass plates such as polycarbonate plates, (meth)acrylic plates such as polymethyl methacrylate plates, polyester plates such as acrylonitrile-styrene copolymer plates, acrylonitrile-butadiene-styrene copolymer plates, and polyethylene terephthalate plates, fluorine-based resin plates, polyvinyl chloride plates, chlorinated polyvinyl chloride plates, polypropylene plates, polystyrene plates, polysulfone plates, epoxy resin plates, phenolic resin plates, unsaturated polyester resin plates, and polyimide resin plates. The organic resin plates may be subjected to appropriate surface treatments.

[0071] The first and second transparent substrates may be made of the same material or different materials, for example, one may be inorganic glass and the other organic glass, but it is preferred that both the first and second transparent substrates are inorganic glass or organic glass. The thickness of each of the glass plates used as the first and second transparent substrates is not particularly limited, but is, for example, about 0.1 to 15 mm, preferably 0.5 to 5 mm. The thicknesses of the glass plates may be the same or different.

[0072] The transparent substrate may be a glass plate alone, or may be a glass plate to which other members are attached. The transparent substrate may be a glass plate to which functional members are attached, so that various functions are imparted. The other member may be, for example, a member constituting an electronic device, an optical member, or the like, but is preferably a member constituting a display device. The display device may be a liquid crystal display device, an organic EL display device, an LED display device, a segment display device, or the like. Of these, the display device is preferably a liquid crystal display device.

[0073] The display device may be, for example, a display panel having a glass plate as a substrate on which a display layer such as a liquid crystal layer or an organic EL layer, and light-emitting elements, and the glass plate that forms the substrate of the display panel may be used as a transparent base material. Furthermore, functional layers such as a conductive layer, an antireflection layer, or a hard coat layer that constitutes a functional film, electrode, sensor, etc., which will be described later, may be laminated on the glass plate, and the transparent substrate may be a glass plate on which such functional films or functional layers are laminated. Therefore, the bonding surface with the interlayer film for laminated glass, on which the interlayer film for laminated glass is directly laminated, may be the glass plate itself, or it may be the surface of a functional film or functional layer.

[0074] When two or more interlayer films for laminated glass are provided in the laminate, it is preferable that all of the interlayer films for laminated glass are the interlayer films for laminated glass of the present invention, as described above, but some of the interlayer films for laminated glass may be other than the interlayer film for laminated glass of the present invention. In addition, another layer such as an adhesive layer may be provided between the functional layer and the interlayer film for laminated glass as appropriate.

[0075] [Layer structure of optical laminate] Next, the layer structure of the optical laminate will be described in detail with reference to the drawings and embodiments. As shown in Fig. 1, in a first embodiment of the present invention, the optical laminate is an optical laminate 1A in which one interlayer film for laminated glass (thermoplastic resin layer (A)) 10 is provided between first and second transparent substrates 20, 30. In the optical laminate 1A, the interlayer film for laminated glass 10 is adhered to both the first and second transparent substrates 20, 30, joining them together.

[0076] In the first embodiment, at least one of the first and second transparent substrates 20, 30 may have other components attached thereto, as described above. Specifically, functional components constituting electronic devices such as display devices, optical components, etc. may be attached thereto, or the above-mentioned functional films, functional layers, etc. may be laminated thereon. In particular, it is preferable that a member constituting a display device, particularly a liquid crystal display device, is attached to at least one of the first and second transparent base materials 20, 30. That is, at least one of the first and second transparent base materials 20, 30 may be a glass plate constituting a display device, and the optical laminate 1A may be provided with a display device using at least one of the first and second transparent base materials 20, 30 as a substrate.

[0077] In the first embodiment, by using the interlayer film 10 for laminated glass that includes the above-described thermoplastic resin layer (A), even when the first and second transparent substrates 20, 30 and the interlayer film 10 for laminated glass are integrated by an autoclave process under low-temperature conditions, it is possible to suppress foaming due to residual air during pressure bonding or due to use in a high-temperature environment. On the other hand, even if a functional member is provided on either the first or second transparent substrate 20, 30, they can be integrated by pressure bonding in an autoclave at low temperatures, so it is possible to prevent deterioration or deactivation of the functional member attached to the optical laminate 1A.

[0078] In another preferred embodiment, the optical laminate may have an interlayer film for laminated glass formed between first and second transparent substrates and comprising a plurality of thermoplastic resin layers. When the interlayer film for laminated glass is formed from a plurality of thermoplastic resin layers, each of the thermoplastic resin layers may be the interlayer film for laminated glass of the present invention having the thermoplastic resin layer (A) described above. When a plurality of thermoplastic resin layers are provided, by making all of the thermoplastic resin layers the thermoplastic resin layer (A), it is possible to suppress foaming due to residual air during pressure bonding or due to use in a high-temperature environment, even when the first and second transparent substrates and the interlayer film for laminated glass are integrated in an autoclave process under low-temperature conditions.

[0079] One embodiment of an optical laminate in which a plurality of thermoplastic resin layers are provided is shown as a second embodiment in Fig. 2. As shown in Fig. 2, an optical laminate 1B according to the second embodiment has a pair of interlayer films for laminated glass 10 provided between first and second transparent substrates 20, 30, and a functional layer 40 further provided between the pair of interlayer films for laminated glass 10. That is, in the optical laminate 1B according to the second embodiment, a laminate 50 in which a functional layer 40 is provided between a pair of thermoplastic resin layers 10 is provided between the first and second transparent substrates 20, 30. Both of the pair of interlayer films for laminated glass 10 are the above-mentioned thermoplastic resin layers (A). In the optical laminated body 1B, one interlayer film 10 for laminated glass is adhered to both the first transparent substrate 20 and the functional layer 40, bonding them together, and the other thermoplastic resin layer 10 is adhered to both the second transparent substrate 30 and the functional layer 40, bonding them together. As a result, the first and second transparent substrates 20, 30, together with the functional layer 40, are integrated by the interlayer film 10 for laminated glass, which is the thermoplastic resin layer (A).

[0080] In the second embodiment, the optical laminate 1B also uses an interlayer film 10 for laminated glass having a thermoplastic resin layer (A), which allows the interlayer film 10 for laminated glass to be pressure-bonded in an autoclave at low temperatures, thereby suppressing foaming due to residual air during pressure bonding or use in a high-temperature environment. Furthermore, by integrating the optical laminate 1B at low temperatures, deterioration and deactivation of the functional layer 40 can be prevented.

[0081] In the second embodiment, two interlayer films 10 for laminated glass and one functional layer 40 are provided in the laminate, but three or more interlayer films for laminated glass and two or more functional layers may be provided in the laminate. In this case, the interlayer films for laminated glass and the functional layers may be alternately arranged in the first and second optical laminates. The interlayer films for laminated glass may be arranged closest to both the first and second transparent substrates. For example, when three interlayer films 10 for laminated glass and two functional layers are provided, they may be arranged in the following order: first transparent substrate / interlayer film for laminated glass / functional layer / interlayer film for laminated glass / functional layer / interlayer film for laminated glass / second transparent substrate. Furthermore, when three or more interlayer films for laminated glass are provided, the above-described thermoplastic resin layer (A) may be used as each interlayer film for laminated glass. When a plurality of interlayer films for laminated glass are provided in the optical laminate, the configurations of the interlayer films for laminated glass may be the same or different.

[0082] <Method of manufacturing optical laminate> The optical laminate of the present invention may be produced by a production method in which at least an interlayer film for laminated glass or a laminate is placed between a first transparent substrate and a second transparent substrate, and these are bonded together by pressure to obtain an optical laminate. Alternatively, an optical laminate incorporating a laminate may be produced by preparing components constituting the laminate, placing the components constituting the laminate between the first transparent substrate and the second transparent substrate, and bonding them together by pressure.

[0083] In the above-mentioned production method, first, first and second transparent substrates and a member (an interlayer film for laminated glass or a laminate) to be disposed between the first and second transparent substrates are prepared. The laminate disposed between the first and second transparent substrates may be selected appropriately depending on the structure of the optical laminate to be obtained, and for example, in the first embodiment, a single interlayer film for laminated glass may be prepared, while in the second embodiment, a laminate consisting of two interlayer films for laminated glass and one functional layer may be prepared.

[0084] Furthermore, as described above, in the optical laminate, a functional member may be attached to at least one of the first and second transparent substrates, and the functional member may be attached to the transparent substrate before being integrated into the optical laminate. Therefore, in the above manufacturing method, at least one of the first and second transparent substrates may be prepared as a transparent substrate to which a functional member is attached. For example, as described above, when the transparent substrate constitutes a substrate of a display device, at least one of the first and second transparent substrates may be prepared as a display device.

[0085] In this production method, an interlayer film for laminated glass or a laminate may be disposed between the first and second transparent substrates as described above, and these may be bonded together to form an integrated optical laminate. Alternatively, components constituting the laminate may be disposed between the first and second transparent substrates, and these may be bonded together to form an integrated optical laminate incorporating the laminate. Here, the interlayer film for laminated glass or the laminate may be arranged according to the layer structure of the optical laminate to be obtained. For example, in the second embodiment, the interlayer film for laminated glass, the functional layer, and the interlayer film for laminated glass may be arranged between the first and second transparent substrates in this order.

[0086] The lamination may be carried out in an autoclave.

[0087] In this manufacturing method, the bonding must be performed under low-temperature conditions, specifically, compression bonding at a temperature of 110°C or less. The bonding is preferably performed at low temperature and low pressure, specifically, compression bonding at a temperature of 110°C or less and a pressure of 1.0 MPa or less. By performing the bonding under low-temperature and low-pressure conditions in this way, it is possible to prevent the functional layer and the functional members (e.g., display devices) attached to the first and second transparent substrates from deteriorating or becoming inactive.

[0088] The temperature during lamination is preferably 110°C or lower from the viewpoint of more reliably preventing deterioration or deactivation of the functional component, and is preferably 60°C or higher, more preferably 70°C or higher, from the viewpoint of preventing the generation of residual air or foaming. The pressure applied when bonding is preferably 1.2 MPa or less, from the viewpoint of more reliably preventing deterioration and deactivation of the functional member. The lower limit of the pressure when laminating is not particularly limited, but when laminating under pressure such as in an autoclave, the pressure is preferably 0.5 MPa or more, more preferably 0.7 MPa or more. When laminating under negative pressure such as in a vacuum bag, the pressure is preferably 0.01 MPa or more, more preferably 0.05 MPa or more. The time for lamination under the above temperature and pressure is not particularly limited, but is, for example, 1 to 120 minutes, and preferably 5 to 60 minutes.

[0089] In this manufacturing method, it is preferable to perform pre-bonding before the lamination. This can further suppress the decrease in transmittance and adhesive strength that occurs during the autoclave process under low-temperature conditions. Pre-bonding may be performed using a vacuum bag, an autoclave under low-temperature conditions, or a press other than these, but among these, it is preferable to perform it using a vacuum bag. Generally, a rubber pack is preferably used as the vacuum bag.

[0090] In this manufacturing method, the preliminary bonding also needs to be performed under low-temperature conditions, specifically, pressure bonding at a temperature of 110°C or less. The lamination is preferably performed at low temperature and low pressure, specifically, pressure bonding at a temperature of 110°C or less and a pressure of 0.1 MPa or less. By performing the preliminary bonding under low-temperature and low-pressure conditions in this way, it is possible to prevent the functional layer and the functional members (e.g., display devices) attached to the first and second transparent substrates from deteriorating or becoming inactive.

[0091] The temperature during preliminary bonding is preferably 100°C or lower from the viewpoint of more reliably preventing deterioration or deactivation of the functional component, and is preferably 60°C or higher, more preferably 70°C or higher, from the viewpoint of preventing the generation of residual air or foaming. Furthermore, the pressure during preliminary bonding is preferably 1.2 MPa or less from the viewpoint of more reliably preventing deterioration or deactivation of the functional member. When preliminary bonding is performed under negative pressure, such as when using a vacuum bag, the pressure may be, for example, 0.1 MPa or less, preferably 0.095 MPa or less, and more preferably 0.09 MPa or less. The pressure for the preliminary bonding is not particularly limited with respect to the lower limit, but when the bonding is performed under pressure, such as in an autoclave, the pressure is preferably 0.5 MPa or more, more preferably 0.7 MPa or more. When the bonding is performed under negative pressure, such as when using a vacuum bag, the pressure is preferably 0.001 MPa or more, more preferably 0.005 MPa or more. The time for lamination under the above temperature and pressure is not particularly limited, but is, for example, 0 seconds to 15 minutes, and preferably 0 to 7 minutes.

[0092] The optical laminate of the present invention is not particularly limited and can be used for various purposes, but can be suitably used as laminated glass. The optical laminate of the present invention is used as window glass for various vehicles such as automobiles and trains, ships and airplanes, various buildings such as buildings, condominiums, detached houses, halls and gymnasiums, machine tools for cutting and polishing, construction machines such as shovels and cranes, and partitions inside various vehicles and buildings, among which, vehicle applications such as automobiles and building applications are preferred, and it is preferably used as window glass for vehicles and building-integrated power generation (BIPV). Furthermore, the optical laminate of the present invention may be used for various display applications, for example, when a display device is constructed using a transparent substrate. As a display application, the above-mentioned window glass or partition may be used as a display. The optical laminate may also be used as a cover glass for various displays, and may be applied to, for example, an in-vehicle display. [Example]

[0093] The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The methods for measuring and evaluating the various physical properties in the present invention are as follows.

[0094] <Preliminary adhesive strength test> Two glass plates 110, 120, an easy-adhesion PET film 130 having easy adhesion on one side, an ultra-thin PET film 140, and an interlayer film for laminated glass 150 were prepared. As shown in Fig. 3, a laminate 100A was produced by laminating the two glass plates 110, 120, the easy-adhesion PET film 130, the ultra-thin PET film 140, and the interlayer film for laminated glass 150. As shown in Fig. 3, the two glass plates 110, 120, the easy-adhesion PET film 130, the ultra-thin PET film 140, and the interlayer film for laminated glass 150 were laminated so that the configuration was glass plate 110 / easy-adhesion PET film 130 / interlayer film for laminated glass 150 / glass plate 120 in the range from an end 131 in the longitudinal direction (y direction) to a position 20 cm away. 3, in a range from a position 20 cm away from the end 131 in the longitudinal direction (y direction) to a position 30 cm away, the two glass plates 110 and 120, the easy-adhesion PET film 130, the ultra-thin film PET film 140, and the interlayer film for laminated glass 150 were laminated so as to form a configuration of glass plate 110 / easy-adhesion PET film 130 / interlayer film for laminated glass 150 / ultra-thin film PET film 140 / glass plate 120. In this manner, the thermoplastic resin layer (A) side of the interlayer film for laminated glass 150 was placed on the glass plate 120 side, with a portion of the thermoplastic resin layer (A) in contact with the glass plate 120 (20 cm in the y direction) and the remainder (10 cm in the y direction) in contact with the ultra-thin film PET film 140. In this case, the easy-adhesion side of the easy-adhesion PET film 130 was in contact with the interlayer film for laminated glass 150. The glass plates 110 and 120 and the interlayer film for laminated glass 150 were laminated together so that the tin surfaces of the glass plates 110 and 120 and the interlayer film for laminated glass 150 were in contact with each other. The resulting laminate 100A was placed in a rubber bag, which was a vacuum bag, and degassed for 5 minutes at a vacuum pressure of 0.09 MPa. Next, while still degassed, the laminate 100A was heated to 90°C at a heating rate of 6°C / min and then cooled to 30°C. The pressure was then returned to normal. The glass plate 110 that had been in contact with the adhesive PET film 130 was peeled from the adhesive PET film 130 to obtain the laminate 100B shown in FIG. 4. Then, as shown in FIG. 5, the laminate film 160 of the adhesive PET film 130 and the interlayer film 150 for laminated glass was cut in the longitudinal direction (y direction) so that the length in the width direction (x direction) was 25 mm, to produce multiple samples 170 for peel tests that were 25 mm wide and adhered to glass. As shown in FIG. 6, each sample 170 was subjected to a 180° peel test in which the sample was peeled from the glass plate along the longitudinal direction (y direction) at a peel rate of 300 mm / min. The 180° peel test was performed at room temperature (23°C) in accordance with JIS K6854-2 (1999) (ISO8510-2 (1990)). A tensile tester (Instron Model 5965 Universal Testing Machine or its equivalent) was used as the measuring instrument. The adhesive strength of the sample was determined by taking the displacement at point 151 (see FIG. 4) where the sample began to peel from the glass plate as 0 mm and then measuring the average adhesive strength between 20 and 180 mm. The lower limit of the adhesive strength between 20 and 180 mm was determined by taking the displacement at point 151 where the sample began to peel from the glass plate as 0 mm. The average value of the adhesive strength of all the samples was taken as the adhesive strength of the interlayer films for laminated glass of the Examples and Comparative Examples, and the minimum value of the lower limit of the adhesive strength of all the samples was taken as the minimum value of the adhesive strength of the interlayer films for laminated glass of the Examples and Comparative Examples. <Materials used> Glass plate: Sanshiba Glass Co., Ltd., product name "float plate glass", size 30cm x 30cm x 3mm Highly adhesive PET film: Toyobo Co., Ltd., product name "Cosmoshine (registered trademark) A4160", size 30 cm x 42 cm x 0.100 mm Ultra-thin PET film: Toray Industries, product name "Lumirror Film", size 30cm x 15cm x 0.025mm

[0095] <Appearance after lamination> The interlayer films for laminated glass obtained in the Examples and Comparative Examples were held at constant temperature and humidity conditions of 23°C and 28% RH for 4 hours, and then laminated between two 10 cm x 10 cm pieces of clear glass (3.0 mm thick) to obtain a laminate. The laminate was placed in a rubber bag, which was a vacuum bag, and degassed for 5 minutes at a vacuum pressure of 0.09 MPa. Next, while still degassed, the laminate was heated to 90°C at a heating rate of 6°C / min and then cooled to 30°C. The pressure was then returned to normal. The obtained optical laminate was placed on a blackout curtain, and the transparency of the optical laminate was visually observed and rated on a 4-point scale according to the amount of remaining air. A: No remaining air B: A small amount of air remains C: Some air remains D: A lot of air remains

[0096] <Adhesion test> The interlayer films for laminated glass obtained in the Examples and Comparative Examples were held at constant temperature and humidity conditions of 23°C and 28% RH for 4 hours, and then laminated between two 10 cm x 10 cm pieces of clear glass (3.0 mm thick) with the tin side of the glass in contact with the interlayer film for laminated glass to obtain a laminate. The obtained laminate was pre-pressed using a heated roll at 170°C. After pressing, the laminate was pressed again for 20 minutes in an autoclave at 140°C and 1.3 MPa to obtain an optical laminate. The obtained optical laminate was left standing for 16 hours in an environment at a temperature of -18°C ± 0.6°C, and the center of this laminated glass (150 mm x 150 mm) was hit with a hammer with a 0.45 kg head to crush the glass particles to a particle size of 6 mm or less. After partial peeling of the glass, the degree of film exposure was measured, and the pummel value was calculated as shown in Table 1.

[0097] [Table 1] A: Pummel value is 2 to 8 B: Pummel value is 1 or less or 9 or more

[0098] <High temperature heat resistance> The interlayer films for laminated glass obtained in the Examples and Comparative Examples were held at constant temperature and humidity conditions of 23°C and 28% RH for 4 hours, and then laminated between two 10 cm x 10 cm pieces of clear glass (3.0 mm thick) to obtain a laminate. The obtained laminate was temporarily pressed using a heated roll at 170°C. After pressing, further pressing was performed in an autoclave at 140°C and 1.3 MPa for 20 minutes to obtain an optical laminate. The obtained optical laminate was stored in an environment of 100°C for 2000 hours, and then the presence or absence of bubbles and yellowing within the optical laminate was visually inspected. A: No foaming, no yellowing B: Slight foaming and yellowing of the edges C: Numerous bubbles, yellowing throughout

[0099] The thermoplastic resins used in the examples and comparative examples were prepared as follows. (Resin 1) A reactor equipped with a stirrer was charged with 1800 ml of ion-exchanged water and 200 g of polyvinyl alcohol A (average degree of polymerization 1700, degree of saponification 99 mol%), and the mixture was heated and dissolved while stirring to obtain a polyvinyl alcohol solution. Next, 30% hydrochloric acid was added as a catalyst to this solution so that the hydrochloric acid concentration was 0.2% by mass. The temperature was then adjusted to 15°C, and n-butyl aldehyde was added with stirring to 10 mol%. Subsequently, n-butyl aldehyde was added to 60 mol%, resulting in the precipitation of a white granular polyvinyl butyral resin. Ten minutes after the precipitation, 30% hydrochloric acid was added so that the hydrochloric acid concentration was 1.8% by mass. The temperature was then raised to 53°C, and the mixture was aged at this aging temperature for 2 hours. Next, the solution was cooled and neutralized, and then the polyvinyl butyral resin was washed with water and dried to obtain Resin 1 (polyvinyl butyral resin, hydroxyl group content 30.8 mol%, acetalization degree 68.4 mol%, acetylation degree 0.8 mol%, polymerization degree 1700).

[0100] (Resin 2) Instead of aging for 2 hours at an aging temperature of 53° C., aging was performed for 2 hours at an aging temperature of 63° C. Otherwise, the procedure was the same as for Resin 1 to obtain Resin 2 (polyvinyl butyral resin, hydroxyl group content 30.4 mol%, acetalization degree 68.8 mol%, acetylation degree 0.8 mol%, polymerization degree 1700).

[0101] The plasticizers used in the examples and comparative examples are as follows. 3GO: Triethylene glycol-di-2-ethylhexanoate

[0102] Example 1 A resin composition was obtained by mixing 100 parts by mass of resin 1 with 40 parts by mass of a plasticizer (triethylene glycol-di-2-ethylhexanoate: 3GO). The obtained resin composition was used to produce a film-like interlayer film for laminated glass with a thickness of 760 μm using an extruder. The obtained interlayer film for laminated glass was embossed using an embossing roll. Two 3.0 mm clear glass sheets were also prepared. Next, the interlayer film for laminated glass was placed on one of the clear glass panes so that the tin side of the glass was in contact with the interlayer film for laminated glass, and then the other clear glass pane was placed on top of the interlayer film for laminated glass to obtain a laminate. The obtained laminate was temporarily pressed using a heated roll at 170°C. After pressing, the laminate was pressed for 20 minutes using an autoclave at 140°C and 1.3 MPa to obtain an optical laminate.

[0103] (Examples 2 to 3 and Comparative Examples 1 to 2) The same procedure as in Example 1 was carried out except that the amount and type of resin used and the amount of plasticizer were changed as shown in Table 2 and the embossing roll used for embossing was changed.

[0104] [Table 2]

[0105] The laminated glass interlayer films of Examples 1 to 3 above had an average adhesive strength of 20 N or more in a preliminary adhesive strength test, which reduced residual air after bonding and resulted in high transmittance. Furthermore, the laminated glass interlayer films of Examples 1 to 3 also had high adhesive strength, with the minimum adhesive strength being 12 N or more in a preliminary adhesive strength test. On the other hand, the laminated glass interlayer films of Comparative Examples 1 and 2 had an average adhesive strength of less than 20 N in the preliminary adhesive strength test, which resulted in a large amount of residual air after bonding and a significant decrease in transmittance. Also, the laminated glass interlayer films of Comparative Examples 1 and 2 had low adhesive strength, with the minimum adhesive strength being less than 12 N in the preliminary adhesive strength test. [Explanation of symbols]

[0106] 1A, 1B Optical laminate 10, 150 Interlayer film for laminated glass (thermoplastic resin layer (A)) 20 First transparent substrate 30 Second transparent substrate 40 Functional Layers 50, 100A, 100B laminate 110, 120 glass plates 130 Easy-adhesive PET film 140 Ultra-thin PET film 160 laminated film 170 samples

Claims

1. An interlayer film for laminated glass having a single-layer structure or a multi-layer structure, At least a thermoplastic resin layer (A) containing a thermoplastic resin, When the interlayer film for laminated glass has a multilayer structure, at least one outermost layer is the thermoplastic resin layer (A), An interlayer film for laminated glass having an average adhesive strength of 20 N or more for all samples in a preliminary adhesive strength test conducted under the following conditions. (Preliminary adhesive strength test conditions) Two 30 cm × 30 cm glass plates, a 30 cm × 42 cm highly adhesive PET film having high adhesive properties on one side, a 30 cm × 15 to 17 cm ultra-thin PET film, and a 30 cm × 30 cm interlayer film for laminated glass are prepared. The highly adhesive PET film is arranged so that the highly adhesive side thereof contacts the interlayer film for laminated glass, and the thermoplastic resin layer (A) of the interlayer film for laminated glass contacts the glass plates and the ultra-thin PET film. At this time, the two glass plates, the easy-adhesion PET film, the ultra-thin PET film, and the interlayer film for laminated glass are laminated so that in the range from the longitudinal end of the easy-adhesion PET film to a distance of 20 cm in the longitudinal direction of the easy-adhesion PET film, the structure is glass plate / easy-adhesion PET film / interlayer film for laminated glass / glass plate, and in the range from a distance of 20 cm to a distance of 30 cm in the longitudinal direction of the easy-adhesion PET film, the structure is glass plate / easy-adhesion PET film / interlayer film for laminated glass / thin PET film / glass plate. The laminated structure is formed so that the tin side of the glass contacts the interlayer film for laminated glass. Then, vacuuming is performed at room temperature for 5 minutes at an absolute pressure of 0.09 MPa. The temperature is then increased to 90°C at a heating rate of 6°C / min, and after reaching 90°C, it is cooled to room temperature. The glass plate that had been in contact with the adhesive PET film was then peeled from the adhesive PET film, and the laminated film of the adhesive PET film and the interlayer film for laminated glass was cut along the longitudinal direction of the adhesive PET film so that the width was 25 mm, to prepare 12 samples for peel tests each having a width of 25 mm and adhered to the glass. A 180° peel test was then performed on each sample, in which the sample was peeled from the glass plate along the longitudinal direction at a peel rate of 300 mm / min. The adhesive strength of the sample was determined by the average adhesive strength between 20 and 180 mm of displacement, where the displacement at the point where the sample began to peel from the glass plate was defined as 0 mm.

2. 2. The interlayer film for laminated glass according to claim 1, wherein, in the preliminary adhesion test, when the displacement at the point where the sample starts to peel from the glass plate is taken as 0 mm, and the lower limit of the adhesive strength between 20 and 180 mm is taken as the lower limit of the adhesive strength of that sample, the lowest lower limit of the adhesive strength of all samples in the preliminary adhesion test is 12 N or more.

3. The interlayer film for laminated glass according to claim 1 , further comprising a colorant.

4. The interlayer film for laminated glass according to claim 1 , wherein the thermoplastic resin layer (A) contains a polyvinyl acetal resin and a plasticizer.

5. 5. The interlayer film for laminated glass according to claim 4, wherein the content of the plasticizer is 30 to 50 parts by mass per 100 parts by mass of the polyvinyl acetal resin.

6. 5. The interlayer film for laminated glass according to claim 4, wherein the plasticizer is at least one plasticizer selected from the group consisting of organic ester plasticizers and organic ether plasticizers.

7. A laminate comprising the interlayer film for laminated glass according to any one of claims 1 to 6 and a functional layer different from the interlayer film for laminated glass.

8. An optical laminate comprising: a first transparent substrate; a second transparent substrate; and the interlayer film for laminated glass according to any one of claims 1 to 6, which is disposed between the first and second transparent substrates.

9. An optical laminate comprising: a first transparent substrate; a second transparent substrate; and the laminate according to claim 7 disposed between the first and second transparent substrates.

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