Interlayer film for laminated glass, and laminated glass

Abstract

The present invention aims to provide an interlayer film for a laminated glass capable of exhibiting high deaeration properties in a vacuum deaeration method and enabling production of a highly transparent laminated glass, and a laminated glass including the interlayer film for a laminated glass. The present invention relates to an interlayer film for a laminated glass, having a large number of recesses on at least one surface, the recesses each having a groove shape with a continuous bottom and being regularly adjacent and parallel to each other, the recesses each having a radius of rotation R of a bottom of the groove shape with a continuous bottom of 45 μm or less.

Claims

1. An interlayer film for a laminated glass, having recesses on at least one surface, the recesses each having a groove shape with a continuous bottom and being adjacently and regularly arranged in parallel with each other, the recesses each having a radius of rotation R of a bottom of the groove shape with a continuous bottom of 45 μm or less, wherein each highest point determined from a roughness curve drawn in conformity with JIS B 0601 (1994) in a direction of a line representing the shortest distance between deepest bottoms of adjacent recesses each having a groove shape with a continuous bottom is not at the center of the line representing the shortest distance between the deepest bottoms, and roughness Rz of the recesses each having a groove shape with a continuous bottom is 20 μm or more.

2. The interlayer film for a laminated glass according to claim 1, wherein the recesses each have a radius of rotation R of the bottom of the groove shape with a continuous bottom of 0.1 μm or more and 45 μm or less.

3. The interlayer film for a laminated glass according to claim 1, wherein an interval Sm between the recesses each having a groove shape with a continuous bottom is 400 μm or less.

4. The interlayer film for a laminated glass according to claim 1, wherein roughness Rz of the recesses each having a groove shape with a continuous bottom is 60 μm or less.

5. The interlayer film for a laminated glass according to claim 1, wherein the surface having recesses further has projections, and the projections each have a non-planar apex.

6. The interlayer film for a laminated glass according to claim 1, wherein the interlayer film for a laminated glass contains at least one metal selected from the group consisting of alkali metals, alkaline earth metals, and magnesium, and the amount of the at least one metal selected from the group consisting of alkali metals, alkaline earth metals, and magnesium is 1 ppm or more and 500 ppm or less.

7. The interlayer film for a laminated glass according to claim 1, wherein the interlayer film for a laminated glass has recesses on both one surface and an other surface opposite to the one surface, the recesses each have a groove shape with a continuous bottom, and the recesses each having a groove shape with a continuous bottom on the one surface and the recesses each having a groove shape with a continuous bottom on the other surface form an intersection angle θ of more than 0°.

8. The interlayer film for a laminated glass according to claim 1, wherein the interlayer film for a laminated glass has a laminated structure including a first resin layer, a second resin layer, and a third resin layer stacked in said order in a thickness direction, and the first resin layer and the third resin layer have different thicknesses.

9. A laminated glass including: a pair of glass plates; and the interlayer film for a laminated glass according to claim 1 interposed between the pair of glass plates.

10. The interlayer film for a laminated glass according to claim 1, wherein the radius of rotation R of the bottom of the groove shape with a continuous bottom is measured by the following method: creating a cross section by cutting the interlayer film in a direction perpendicular to the groove shape with a continuous bottom and in parallel with a thickness direction of the interlayer film, wherein a cut plane resulting from the cutting is not deformed, photographing the cross section at a magnification of 277 times to obtain an image, enlarging the obtained image to 50 μm/20 mm to obtain an enlarged image, inscribing a circle at the bottom of the groove shape with a continuous bottom in the enlarged image, and determining the radius of the inscribed circle, wherein the radius of the inscribed circle at the bottom of the groove shape with a continuous bottom is the radius of rotation R.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a view schematically illustrating an exemplary interlayer film for a laminated glass in which recesses each having a groove shape with a continuous bottom are adjacent and parallel to each other at equal intervals on a surface.

(2) FIG. 2 is a view schematically illustrating an exemplary interlayer film for a laminated glass in which recesses each having a groove shape with a continuous bottom are adjacent and parallel to each other at equal intervals on a surface.

(3) FIG. 3 is a view schematically illustrating an exemplary interlayer film for a laminated glass in which recesses each having a groove shape with a continuous bottom are adjacent and parallel to each other not at equal intervals.

(4) FIG. 4 is a view schematically explaining a radius of rotation R of a bottom of a recess having a groove shape with a continuous bottom and an interval Sm between recesses.

(5) FIG. 5 is a view schematically illustrating an interlayer film for a laminated glass in which the highest point determined from a roughness curve drawn in conformity with JIS B 0601 (1994) in a direction of a line representing the shortest distance between deepest bottoms of adjacent recesses each having a groove shape with a continuous bottom is not at the center of the line representing the shortest distance between the deepest bottom.

DESCRIPTION OF EMBODIMENTS

(6) Embodiments of the present invention are more specifically described in the following with reference to, but not limited to, examples.

Example 1

(7) (1) Preparation of a Resin Composition

(8) Polyvinyl alcohol having an average degree of polymerization of 1700 was acetalized with n-butyraldehyde to give polyvinyl butyral (acetyl group content: 1 mol %, butyral group content: 69 mol %, hydroxy group content: 30 mol %). To 100 parts by mass of the polyvinyl butyral was added 40 parts by mass of triethylene glycol-di-2-ethylhexanoate (3GO) as a plasticizer, and kneaded well with a mixing roll to give a resin composition.

(9) (2) Production of an Interlayer Film for a Laminated Glass

(10) The obtained resin composition was extruded to provide an interlayer film for a laminated glass having a thickness of 760 μm.

(11) (3) Formation of Projections and Recesses

(12) In the first step, a random pattern of projections and recesses was transferred to both surfaces of the interlayer film for a laminated glass by the following procedure. A pair of rolls in the same shape having a coarse main emboss pattern and a fine sub-emboss pattern was prepared by forming random projections and recesses on the surfaces of iron rolls with an abrasive material, performing vertical grinding thereon, and further forming finer projections and recesses on planar portions after the grinding with a finer abrasive material. Using the pair of rolls as a device for transferring a pattern of projections and recesses, a random pattern of projections and recesses was transferred to both surfaces of the obtained interlayer film for a laminated glass. The transferring conditions employed here were a temperature of the interlayer film for a laminated glass of 80° C., a temperature of the rolls of 145° C., a linear velocity of 10 m/min, a line width of 1.5 m, and a pressure of 0 to 200 kN/m.

(13) In the second step, projections and recesses in a pattern of grooves each with a continuous bottom (shape of engraved lines) were formed by the following procedure. A pair of rolls including a metal roll having a surface milled with a triangular oblique line-type mill and a rubber roll having a JIS hardness of 45 to 75 was used as a device for transferring a pattern of projections and recesses. The interlayer film for a laminated glass having a random pattern of projections and recesses transferred in the first step was passed through the device for transferring a pattern of projections and recesses, thereby forming projections and recesses in which recesses each having a groove shape with a continuous bottom (shape of an engraved line) were adjacent and parallel to each other at equal intervals on a first surface. The transferring conditions employed here were a temperature of the interlayer film for a laminated glass of an ambient temperature, a temperature of the rolls of 140° C., a linear velocity of 10 m/min, and a pressure of 500 kPa.

(14) Then, the same operations were performed on a second surface of the interlayer film for a laminated glass to form recesses each having a groove shape with a continuous bottom (shape of an engraved line).

(15) (4) Analysis of Projections and Recesses on First Surface and Second Surface

(16) The interval Sm and the roughness Rz of the recesses each having a groove shape with a continuous bottom on the first surface and the second surface of the obtained interlayer film for a laminated glass were measured by methods in conformity with JIS B 0601 (1994). The measurement was performed in a direction perpendicular to the groove shape with a continuous bottom at a cut-off value of 2.5 mm, a standard length of 2.5 mm, an evaluation length of 12.5 mm, and a measurement rate of 0.5 mm/s, with a stylus having a tip radius of 2 μm and a tip angle of 60°. Since the shape of the surface of the interlayer film for a laminated glass varies, the measurement was performed at five sites in the plane, and the average thereof was taken as the evaluation result.

(17) The interlayer film for a laminated glass was cut with a single-edged razor (FAS-10 produced by FEATHER Safety Razor Co., Ltd.) in a direction perpendicular to the grooves each with a continuous bottom and in parallel with the thickness direction of the film in such a manner that the cut plane was not deformed. Specifically, the razor was not slid in the direction perpendicular to the recesses but pushed out in a direction parallel to the thickness direction. The cross section was observed using a microscope (e.g., “DSX-100” produced by Olympus Corporation). The cross section was photographed at a magnification of 277 times. The obtained image was enlarged to 50 μm/20 mm for analysis using the measurement software included in accessory software, and the radius of a circle inscribed at the bottom of the groove with a continuous bottom (i.e., radius of rotation R) was obtained. The measurement was performed at 23° C. and 30 RH %.

(18) (5) Production of a Laminate

(19) The obtained interlayer film for a laminated glass was sandwiched between two clear glass plates (30 cm in length×30 cm in width×2.5 mm in thickness) and the portions of the film protruding from the glass plates were cut off, thereby preparing a laminate. The resulting laminate was preliminarily heated until the glass surface temperature reached 50° C. in an oven, and transferred into a rubber bag, which was then connected to a vacuum suction device. The rubber bag was heated so that the temperature of the laminate (preliminary pressure bonding temperature) reached 90° C., while being held under a reduced pressure of −600 mmHg for 10 minutes. Thereafter, the pressure was returned to atmospheric pressure, whereby the preliminary pressure bonding was completed.

Examples 2 to 5, Comparative Examples 1 to 6

(20) An interlayer film for a laminated glass and a laminate were produced as in Example 1, except that the acetyl group content, butyral group content, and hydroxy group content of the polyvinyl butyral used and the amount of the plasticizer were changed as shown in Table 1 and that the radius of rotation R, the interval Sm, and the roughness Rz of the recesses each having a groove shape with a continuous bottom on the first surface and the second surface were changed as shown in Table 1 by changing the shape of the metal roll having a surface milled with a triangular oblique line-type mill.

Example 6

(21) (1) Preparation of a Resin Composition

(22) Polyvinyl alcohol having an average degree of polymerization of 1700 was acetalized with n-butyraldehyde to give polyvinyl butyral (acetyl group content: 1 mol %, butyral group content: 69 mol %, hydroxy group content: 30 mol %). To 100 parts by mass of the polyvinyl butyral were added 40 parts by mass of triethylene glycol-di-2-ethylexanoate (3GO) as a plasticizer and a mixture (mass ratio of 1:1) of magnesium 2-ethylbutyrate and magnesium acetate as an adhesion modifier in such an amount that the magnesium content of the resulting interlayer film for a laminated glass became 50 ppm. The mixture was kneaded well with a mixing roll to give a resin composition.

(23) (2) Production of an Interlayer Film for a Laminated Glass

(24) The obtained resin composition was extruded to form an interlayer film for a laminated glass having a thickness of 760 μm.

(25) (3) Formation of Projections and Recesses

(26) In the first step, a random pattern of projections and recesses was transferred to both surfaces of the interlayer film for a laminated glass by the following procedure. A pair of rolls in the same shape having a coarse main emboss pattern and a fine sub-emboss pattern was prepared by forming random projections and recesses on the surfaces of iron rolls with an abrasive material, performing vertical grinding thereon, and further forming finer projections and recesses on planar portions after the grinding with a finer abrasive material. Using the pair of rolls as a device for transferring a pattern of projections and recesses, a random pattern of projections and recesses was transferred to both surfaces of the obtained interlayer film for a laminated glass. The transferring conditions employed here were a temperature of the interlayer film for a laminated glass of 80° C., a temperature of the rolls of 145° C., a linear velocity of 10 m/min, a line width of 1.5 m, and a pressure of 0 to 200 kN/m.

(27) In the second step, projections and recesses in a pattern of grooves each with a continuous bottom (shape of engraved lines) were formed by the following procedure. A pair of rolls including a metal roll having a surface milled with a triangular oblique line-type mill and a rubber roll having a JIS hardness of 45 to 75 was used as a device for transferring a pattern of projections and recesses. The interlayer film for a laminated glass having a random pattern of projections and recesses transferred in the first step was passed through the device for transferring a pattern of projections and recesses, thereby forming projections and recesses in which recesses each having a groove shape with a continuous bottom (shape of an engraved line) were adjacent and parallel to each other at equal intervals on a first surface. The transferring conditions employed here were a temperature of the interlayer film for a laminated glass of 80° C., a temperature of the rolls of 140° C., a linear velocity of 10 m/min, a line width of 1.5 m, and a pressure of 0 to 500 kPa.

(28) Then, the same operations were performed on a second surface of the interlayer film for a laminated glass to form recesses each having a groove shape with a continuous bottom (shape of an engraved line). At that time, the intersection angle θ between the recesses each having a groove shape with a continuous bottom on the first surface and the recesses each having a groove shape with a continuous bottom on the second surface was set to 90°.

(29) (4) Analysis of Projections and Recesses on First Surface and Second Surface

(30) The interval Sm and the roughness Rz of the recesses each having a groove shape with a continuous bottom on the first surface and the second surface of the obtained interlayer film for a laminated glass were measured by the methods in conformity with JIS B 0601 (1994). The measurement was performed in a direction perpendicular to the groove shape with a continuous bottom at a cut-off value of 2.5 mm, a standard length of 2.5 mm, an evaluation length of 12.5 mm, and a measurement rate of 0.5 mm/s, with a stylus having a tip radius of 2 μm and a tip angle of 60°. Since the shape of the surface of the interlayer film for a laminated glass varies, the measurement was performed at five sites in the plane, and the average thereof was taken as the evaluation result.

(31) The interlayer film for a laminated glass was cut with a single-edged razor (FAS-10 produced by FEATHER Safety Razor Co., Ltd.) in a direction perpendicular to the grooves each with a continuous bottom and in parallel with the thickness direction of the film in such a manner that the cut plane was not deformed. Specifically, the razor was not slid in the direction perpendicular to the recesses but pushed out in a direction parallel to the thickness direction. The cross section was observed using a microscope (e.g., “DSX-100” produced by Olympus Corporation). The cross section was photographed at a magnification of 277 times. The obtained image was enlarged to 50 μm/20 mm for analysis using the measurement software included in accessory software, and the radius of a circle inscribed at the bottom of the groove with a continuous bottom (i.e., radius of rotation R) was obtained. The measurement was performed at 23° C. and 30 RH %.

(32) When a roughness curve is drawn in conformity with JIS B 0601 (1994) in a direction of a line representing the shortest distance between deepest bottoms of adjacent recesses each having a groove shape with a continuous bottom of the obtained interlayer film for a laminated glass, the highest point of the obtained roughness curve was at the center of the line representing the shortest distance between the deepest bottoms. In other words, the adjacent recesses each having a groove shape with a continuous bottom of the obtained interlayer film for a laminated glass were symmetric with respect to a line perpendicularly crossing the center of the line representing the shortest distance between deepest bottoms.

(33) (5) Production of a Laminate

(34) The obtained interlayer film for a laminated glass was sandwiched between two clear glass plates (30 cm in length×30 cm in width×2.5 mm in thickness) and the portions of the film protruding from the glass plates were cut off, thereby preparing a laminate. The resulting laminate was preliminarily heated to the glass surface temperature of 50° C. in an oven, and transferred into a rubber bag, which was then connected to a vacuum suction device. The rubber bag was heated so that the temperature of the laminate (preliminary pressure bonding temperature) reached 90° C., while being held under a reduced pressure of −600 mmHg for 10 minutes. Thereafter, the pressure was returned to atmospheric pressure, whereby the preliminary pressure bonding was completed.

Examples 7 to 14

(35) An interlayer film for a laminated glass and a laminate were produced as in Example 6, except that the acetyl group content, butyral group content, and hydroxy group content of the polyvinyl butyral used, the amount of the plasticizer, and the amount of magnesium (Mg) were changed as shown in Table 2 and that the radius of rotation R, the interval Sm, the roughness Rz, and the intersection angle θ of the recesses each having a groove shape with a continuous bottom on the first surface and the second surface were changed as shown in Table 2 by changing the shape of the metal roll having a surface milled with a triangular oblique line-type mill.

(36) When a roughness curve was drawn in conformity with JIS B 0601 (1994) in a direction of a line representing the shortest distance between deepest bottoms of adjacent recesses each having a groove shape with a continuous bottom of each of the obtained interlayer films for a laminated glass in Examples 7 to 11, the highest point of the obtained roughness curve was at the center of the line representing the shortest distance between the deepest bottoms. In other words, the adjacent recesses each having a groove shape with a continuous bottom of each of the obtained interlayer films for a laminated glass of Examples 7 to 11 were symmetric with respect to a line perpendicularly crossing the center of the line representing the shortest distance between the deepest bottoms.

(37) In contrast, when a roughness curve was drawn in conformity with JIS B 0601 (1994) in a direction of a line representing the shortest distance between deepest bottoms of adjacent recesses each having a groove shape with a continuous bottom of each of the obtained interlayer films for a laminated glass of Examples 12 to 14, the highest point of the obtained roughness curve was not at the center of the line representing the shortest distance between the deepest bottoms. In other words, the adjacent recesses each having a groove shape with a continuous bottom of each of the obtained interlayer films for a laminated glass of Examples 12 to 14 were asymmetric with respect to a line perpendicularly crossing the center of the line representing the shortest distance between the deepest bottoms.

Example 15

(38) (Preparation of a Resin Composition for Protective Layers)

(39) Polyvinyl alcohol having an average degree of polymerization of 1700 was acetalized with n-butyraldehyde to give polyvinyl butyral (acetyl group content: 1 mol %, butyral group content: 69 mol %, hydroxy group content: 30 mol %). To 100 parts by mass of the polyvinyl butyral were added 36 parts by mass of triethylene glycol-di-2-ethylhexanoate (3GO) as a plasticizer. In addition, a mixture (mass ratio of 1:1) of magnesium 2-ethylbutyrate and magnesium acetate as an adhesion modifier was added thereto in such an amount that the magnesium content became 50 ppm. The mixture was kneaded well with a mixing roll to give a resin composition for protective layers.

(40) (Preparation of a Resin Composition for Sound Insulation Layers)

(41) Polyvinyl alcohol having an average degree of polymerization of 2300 was acetalized with n-butyraldehyde to give polyvinyl butyral (acetyl group content: 12.5 mol %, butyral group content: 64 mol %, hydroxy group content: 23.5 mol %). To 100 parts by mass of the polyvinyl butyral were added 76.5 parts by mass of triethylene glycol-di-2-ethylhexanoate (3GO) as a plasticizer, and the mixture was mixed well with a mixing roll to give a resin composition for sound insulation layers.

(42) (Production of an Interlayer Film for a Laminated Glass)

(43) The resin composition for sound insulation layers and the resin composition for protective layers were co-extruded to form an interlayer film for a laminated glass (width: 100 cm) having a triple layer structure including a first protective layer (thickness: 300 μm), a sound insulation layer (thickness: 100 μm), and a second protective layer (thickness: 400 μm) stacked in the stated order in the thickness direction.

(44) (Formation of Projections and Recesses)

(45) In the first step, a random pattern of projections and recesses was transferred to both surfaces of the interlayer film for a laminated glass by the following procedure. A pair of rolls in the same shape having a coarse main emboss pattern and a fine sub-emboss pattern was prepared by forming random projections and recesses on the surfaces of iron rolls with an abrasive material, performing vertical grinding thereon, and further forming finer projections and recesses on planar portions after the grinding with a finer abrasive material. Using the pair of rolls as a device for transferring a pattern of projections and recesses, a random pattern of projections and recesses was transferred to both surfaces of the obtained interlayer film for a laminated glass. The transferring conditions employed here were a temperature of the interlayer film for a laminated glass of 80° C., a temperature of the rolls of 145° C., a linear velocity of 10 m/min, a line width of 1.5 m, and a pressure of 0 to 200 kN/m.

(46) In the second step, projections and recesses in a pattern of grooves each with a continuous bottom (shape of engraved lines) were formed by the following procedure. A pair of rolls including a metal roll having a surface milled with a triangular oblique line-type mill and a rubber roll having a JIS hardness of 45 to 75 was used as a device for transferring a pattern of projections and recesses. The interlayer film for a laminated glass having a random pattern of projections and recesses transferred in the first step was passed through the device for transferring a pattern of projections and recesses, thereby forming projections and recesses in which recesses each having a groove shape with a continuous bottom (shape of an engraved line) were adjacent and parallel to each other at equal intervals on a first surface of the interlayer film for a laminated glass. The transferring conditions employed here were a temperature of the interlayer film for a laminated glass of 80° C., a temperature of the rolls of 140° C., a linear velocity of 10 m/min, a line width of 1.5 m, and a pressure of 0 to 500 kPa.

(47) Then, the same operation was performed on a second surface of the interlayer film for a laminated glass to form recesses each having a groove shape with a continuous bottom (shape of engraved lines). At that time, the intersection angle θ between the recesses each having a groove shape with a continuous bottom on the first surface and the recesses each having a groove shape with a continuous bottom on the second surface was set to 20°.

(48) The radius of rotation R, the interval Sm, and the roughness Rz of the recesses each having a groove shape with a continuous bottom on the first surface and the second surface were measured by the same methods as those in Example 1. When a roughness curve was drawn in conformity with JIS B 0601 (1994) in a direction of a line representing the shortest distance between deepest bottoms of adjacent recesses each having a groove shape with a continuous bottom of the obtained interlayer film for a laminated glass, the highest point of the obtained roughness curve was at the center of the line representing the shortest distance between the deepest bottoms. In other words, the adjacent recesses each having a groove shape with a continuous bottom of the obtained interlayer film for a laminated glass were symmetric with respect to a line perpendicularly crossing the center of the line representing the shortest distance between deepest bottoms.

(49) (Production of a Laminate and a Laminated Glass)

(50) The obtained interlayer film for a laminated glass was sandwiched between two clear glass plates (30 cm in length×30 cm in width×2.5 mm in thickness) and the portions of the film protruding from the glass plates were cut off, thereby preparing a laminate. The resulting laminate was preliminarily heated to the glass surface temperature of 50° C. in an oven, and transferred into a rubber bag, which was then connected to a vacuum suction device. The rubber bag was heated so that the temperature of the laminate (preliminary pressure bonding temperature) reached 90° C., while being held under a reduced pressure of −600 mmHg for 10 minutes. Thereafter, the pressure was returned to atmospheric pressure, whereby the preliminary pressure bonding was completed.

(51) The preliminarily pressure bonded laminate was placed in an autoclave, and held at a temperature of 140° C. and a pressure of 1300 kPa for 10 minutes. The temperature was lowered to 50° C. and the pressure was returned to atmospheric pressure, whereby the final pressure bonding was completed. A laminated glass was thus prepared.

(52) (Measurement of Plasticizer Content)

(53) The obtained laminated glass was allowed to stand at a temperature of 25° C. and a humidity of 30% for 4 weeks. Then, the laminated glass was cooled in liquid nitrogen to separate the glass from the interlayer film for a laminated glass. The resulting interlayer film for a laminated glass was cut in the thickness direction, and allowed to stand at a temperature of 25° C. and a humidity of 30% for 2 hours. The protective layer was peeled from the sound insulation layer using a finger or a device inserted between the protective layer and the sound insulation layer at a temperature of 25° C. and a humidity of 30%, thereby preparing 10 g of a rectangular sample for measurement of each of the protective layer and the sound insulation layer. The plasticizer in the sample for measurement was extracted in diethyl ether using a Soxhlet extractor for 12 hours, and the amount of the plasticizer in the sample for measurement was determined, thereby obtaining the plasticizer contents of the protective layer and the intermediate layer.

Examples 16 to 21, Comparative Examples 7 to 10

(54) An interlayer film for a laminated glass, a laminate, and a laminated glass were produced as in Example 15, except that the acetyl group content, butyral group content, and hydroxy group content of the polyvinyl butyral used, the amount of the plasticizer, the amount of magnesium (Mg), the thickness of the first protective layer, and the thickness of the second protective layer were changed as shown in Table 3 and that the radius of rotation R, the interval Sm, the roughness Rz, and the intersection angle θ of the recesses each having a groove shape with a continuous bottom on the first surface and the second surface were changed as shown in Table 3 by changing the shape of the metal roll having a surface milled with a triangular oblique line-type mill.

(55) When a roughness curve was drawn in conformity with JIS B 0601 (1994) in a direction of a line representing the shortest distance between deepest bottoms of adjacent recesses each having a groove shape with a continuous bottom of each of the obtained interlayer films for a laminated glass in Examples 16 to 21, the highest point of the obtained roughness curve was at the center of the line representing the shortest distance between the deepest bottoms. In other words, the adjacent recesses each having a groove shape with a continuous bottom of each of the obtained interlayer films for a laminated glass of Examples 16 to 21 were symmetric with respect to a line perpendicularly crossing the center of the line representing the shortest distance between the deepest bottoms.

(56) (Evaluation)

(57) In relation to the interlayer film for a laminated glass and the laminated glass of each of the examples and comparative examples, the parallel light transmittance of the laminate after the preliminary pressure bonding was evaluated by the following method.

(58) Specifically, the parallel light transmittance Tp (%) of the laminate after the preliminary pressure bonding in production of the laminated glass was measured with a haze meter (HM-150 produced by Murakami Color Research Laboratory) in conformity with JIS K 7105.

(59) The parallel light transmittance was measured at five measurement points in total including the intersection of two diagonals of the laminate and 4 points at 10 cm away from the apexes of the laminate in the diagonal direction, and the average of the measured values was taken as the Tp.

(60) Before the measurement, the laminate was cut to give pieces each with a size of 5 cm×5 cm including any of the above measurement points at the center, and the pieces were used as samples for measurement.

(61) Reduction in transparency of the laminated glass is caused by defective deaeration during preliminary pressure bonding. Accordingly, the deaeration properties of the interlayer film for a laminated glass can be evaluated more precisely by measurement of the parallel light transmittance of the laminate after the preliminary pressure bonding than analysis of foaming in the resulting laminated glass.

(62) Tables 1, 2, and 3 show the results.

(63) Interlayer films for a laminated glass and laminates were produced as in Examples 1 to 5 and Comparative Examples 1 to 6, except that the intersection angle between the recesses each having a groove shape with a continuous bottom on the first surface and the recesses each having a groove shape with a continuous bottom on the second surface was set to 20°, and they had the same deaeration properties as those of Examples 1 to 5 and Comparative Examples 1 to 6.

(64) TABLE-US-00001 TABLE 1 Comparative Example 1 Example 2 Example 3 Example 4 Example 5 Example 1 Composition Butyral group content (mol %) 69 69 69 69 69 69 Hydroxy group content (mol %) 30 30 30 30 30 30 Acetyl group content (mol %) 1 1 1 1 1 1 Parts of plasticizer (phr) 40 40 40 40 40 40 First surface Radius of rotation R of recess (μm) 8 63 12 40 25 330 Interval Sm (μm) 189 300 300 195 200 290 Roughness Rz (μm) 44 42 42 41 42 34 Second surface Radius of rotation R of recess (μm) 8 9 10 30 30 220 Interval Sm (μm) 200 399 298 190 195 400 Roughness Rz (μm) 43 48 42 47 42 33 Evaluation Parallel light transmittance of 78 65 72 55 60 26 laminate after preliminary pressure bonding (%) Comparative Comparative Comparative Comparative Comparative Example 2 Example 3 Example 4 Example 5 Example 6 Composition Butyral group content (mol %) 69 69 69 69 69 Hydroxy group content (mol %) 30 30 30 30 30 Acetyl group content (mol %) 1 1 1 1 1 Parts of plasticizer (phr) 40 40 40 40 40 First surface Radius of rotation R of recess (μm) 256 280 47 65 85 Interval Sm (μm) 400 290 203 200 203 Roughness Rz (μm) 44 35 34 47 33 Second surface Radius of rotation R of recess (μm) 230 330 53 59 70 Interval Sm (μm) 300 285 198 195 198 Roughness Rz (μm) 46 30 31 53 33 Evaluation Parallel light transmittance of 45 23 45 49 33 laminate after preliminary pressure bonding (%)

(65) TABLE-US-00002 TABLE 2 Example 6 Example 7 Example 8 Example 9 Example 10 Composition Butyral group content (mol %) 69 69 69 69 69.9 Hydroxy group content (mol %) 30 30 30 30 29 Acetyl group content (mol %) 1 1 1 1 1.1 Parts of plasticizer (phr) 40 40 40 40 41 Mg content (ppm) 50 20 50 50 50 First surface Radius of rotation R of recess (μm) 10 10 20 22 25 Interval Sm (μm) 160 398 300 185 200 Roughness Rz (μm) 30 45 35 33 42 Symmetry of shape Symmetric Symmetric Symmetric Symmetric Symmetric Second surface Radius of rotation R of recess (μm) 10 11 20 25 30 Interval Sm (μm) 143 385 290 178 195 Roughness Rz (μm) 32 44 33 34 42 Symmetry of shape Symmetric Symmetric Symmetric Symmetric Symmetric Intersection angle θ (°) 90 70 20 10 40 Evaluation Parallel light transmittance of 79 55 60 67 58 laminate after preliminary pressure bonding (%) Example 11 Example 12 Example 13 Example 14 Composition Butyral group content (mol %) 68.2 69 69 69 Hydroxy group content (mol %) 31 30 30 30 Acetyl group content (mol %) 0.8 1 1 1 Parts of plasticizer (phr) 39 40 40 40 Mg content (ppm) 100 50 50 50 First surface Radius of rotation R of recess (μm) 18 6 15 10 Interval Sm (μm) 202 200 175 300 Roughness Rz (μm) 40 35 30 29 Symmetry of shape Symmetric Asymmetric Asymmetric Asymmetric Second surface Radius of rotation R of recess (μm) 20 6 13 10 Interval Sm (μm) 198 198 169 292 Roughness Rz (μm) 40 38 33 30 Symmetry of shape Symmetric Asymmetric Asymmetric Asymmetric Intersection angle θ (°) 20 20 20 20 Evaluation Parallel light transmittance of 68 77 78 65 laminate after preliminary pressure bonding (%)

(66) TABLE-US-00003 TABLE 3 Example 15 Example 16 Example 17 Example 18 Example 19 Example 20 First Butyral group content (mol %) 69 69 68.5 69.9 68.5 69.9 protective Hydroxy group content (mol %) 30 30 31 29 31 29 layer Acetyl group content (mol %) 1 1 0.5 1.1 0.5 1.1 Parts of plasticizer (phr) 36 36 36 39 36 39 Mg content (ppm) 50 100 10 50 50 50 Thickness (μm) 300 250 300 300 300 300 Sound Butyral group content (mol %) 64 64 67 77.8 67 77.8 insulation Hydroxy group content (mol %) 23.5 23.5 25 20.7 25 20.7 layer Acetyl group content (mol %) 12.5 12.5 8 1.5 8 1.5 Parts of plasticizer (phr) 76.5 76.5 75 79.3 75 79.2 Thickness (μm) 100 100 100 100 100 100 Second Butyral group content (mol %) 69 69 68.5 69.9 68.5 69.9 protective Hydroxy group content (mol %) 30 30 31 29 31 29 layer Acetyl group content (mol %) 1 1 0.5 1.1 0.5 1.1 Parts of plasticizer (phr) 36 36 36 39 36 39 Mg content (ppm) 50 100 10 50 50 50 Thickness (μm) 400 450 400 400 400 400 First surface Radius of rotation R of recess (μm) 8 12 10 8 10 12 Interval Sm (μm) 189 300 190 201 300 305 Roughness Rz (μm) 44 42 43 45 45 45 Symmetry of shape Symmetric Symmetric Symmetric Symmetric Symmetric Symmetric Second surface Radius of rotation R of recess (μm) 8 10 8 9 9 10 Interval Sm (μm) 200 298 202 187 295 300 Roughness Rz (μm) 43 42 40 46 43 45 Symmetry of shape Symmetric Symmetric Symmetric Symmetric Symmetric Symmetric Intersection angle θ (°) 20 90 70 90 10 20 Evaluation Parallel light transmittance of 76 72 77 80 70 73 laminate after preliminary pressure bonding (%) Comparative Comparative Comparative Comparative Example 21 Example 7 Example 8 Example 9 Example 10 First Butyral group content (mol %) 69 69 69 69 69 protective Hydroxy group content (mol %) 30 30 30 30 30 layer Acetyl group content (mol %) 1 1 1 1 1 Parts of plasticizer (phr) 40 36 36 36 36 Mg content (ppm) 50 50 50 50 50 Thickness (μm) 250 300 300 300 300 Sound Butyral group content (mol %) 64 64 64 64 64 insulation Hydroxy group content (mol %) 23.5 23.5 23.5 23.5 23.5 layer Acetyl group content (mol %) 12.5 12.5 12.5 12.5 12.5 Parts of plasticizer (phr) 76.5 76.5 76.5 76.5 76.5 Thickness (μm) 100 100 100 100 100 Second Butyral group content (mol %) 69 69 69 69 69 protective Hydroxy group content (mol %) 30 30 30 30 30 layer Acetyl group content (mol %) 1 1 1 1 1 Parts of plasticizer (phr) 40 36 36 36 36 Mg content (ppm) 50 50 50 50 50 Thickness (μm) 450 400 400 400 400 First surface Radius of rotation R of recess (μm) 30 300 300 50 100 Interval Sm (μm) 195 290 290 200 205 Roughness Rz (μm) 42 30 33 34 30 Symmetry of shape Symmetric Symmetric Symmetric Symmetric Symmetric Second surface Radius of rotation R of recess (μm) 25 200 340 55 80 Interval Sm (μm) 190 400 285 196 200 Roughness Rz (μm) 45 30 33 33 31 Symmetry of shape Symmetric Symmetric Symmetric Symmetric Symmetric Intersection angle θ (°) 20 20 20 20 20 Evaluation Parallel light transmittance of 60 24 20 43 30 laminate after preliminary pressure bonding (%)

INDUSTRIAL APPLICABILITY

(67) The present invention can provide an interlayer film for a laminated glass capable of exhibiting high deaeration properties in a vacuum deaeration method and enabling production of highly transparent laminated glass, and a laminated glass including the interlayer film for a laminated glass.

REFERENCE SIGNS LIST

(68) 1: One arbitrarily selected recess 2: Recess adjacent to the arbitrarily selected recess 3: Recess adjacent to the arbitrarily selected recess A: Interval between recess 1 and recess 2 B: Interval between recess 1 and recess 3 20: Surface of interlayer film for a laminated glass 21: Recess having a groove shape with a continuous bottom 22: Projection 30: Surface of interlayer film for a laminated glass 31: Recess having a groove shape with a continuous bottom 32: Projection 33: Line representing the shortest distance between deepest bottoms of adjacent recesses each having a groove shape with a continuous bottom 34: Line perpendicularly crossing the center of the line representing the shortest distance between deepest bottoms of adjacent recesses each having a groove shape with a continuous bottom