Laminated glass intermediate film, laminated glass and laminated glass intermediate film production method

Abstract

The present invention aims to provide an interlayer film for a laminated glass which has a multilayer structure including two or more resin layers laminated together and can prevent optical distortion even at high temperatures, a laminated glass including the interlayer film for a laminated glass, and a method of producing the interlayer film for a laminated glass. The present invention relates to an interlayer film for a laminated glass, the interlayer film including: two or more resin layers laminated together, one resin layer having a surface with a ratio (Rz/Sm) of a ten-point average roughness Rz (μm) to an average interval Sm (μm) of projections and recesses of 0.0018 or less as measured in conformity with JIS B-0601(1994) in the following manner: a laminated glass is produced using two clear glass sheets conforming to JIS R3202(1996) and the interlayer film; the interlayer film is peeled away from the clear glass sheets after the laminated glass is cooled with liquid nitrogen; the one resin layer is peeled away from another resin layer that is in direct contact with the one resin layer; and the Rz and Sm of the surface of the one resin layer on the side having been in contact with the other resin layer are measured.

Claims

1. An interlayer film for a laminated glass, the interlayer film comprising: two or more resin layers laminated together including one resin layer and another resin layer that is in direct contact with the one resin layer, the one resin layer, before production of a laminated glass, having a surface with an average interval Sm (μm) of projections and recesses of 300 μm or more, and a ratio (Rz/Sm) of a ten-point average roughness Rz (μm) to the average interval Sm (μm) of projections and recesses of 0.00110 or less as measured in conformity with JIS B-0601(1994) in the following manner: the one resin layer is peeled away from the other resin layer; and the Rz and Sm of the surface of the one resin layer on the side having been in contact with the other resin layer are measured.

2. The interlayer film for a laminated glass according to claim 1, wherein the average interval Sm of projections and recesses of the surface of the one resin layer is 632 μm or more.

3. The interlayer film for a laminated glass according to claim 1, wherein the ten-point average roughness Rz of the surface of the one resin layer is 2.0 μm or less as measured in conformity with JIS B-0601(1994) in the following manner: the one resin layer is peeled away from the other resin layer; and the Rz of the surface of the one resin layer on the side having been in contact with the other resin layer is measured.

4. The interlayer film for a laminated glass according to claim 1, wherein a difference in refractive index between the two or more resin layers is 0.03 or less.

5. The interlayer film for a laminated glass according to claim 1, wherein the one resin layer contains a thermoplastic resin, and the other resin layer that is in direct contact with the one resin layer contains a thermoplastic resin that is different from the thermoplastic resin contained in the one resin layer.

6. The interlayer film for a laminated glass according to claim 1, having a plurality of recesses on at least one surface thereof, wherein the ten-point average roughness Rz of the at least one surface with the plurality of recesses is 10 to 60 μm as measured in conformity with JIS B-0601(1994).

7. The interlayer film for a laminated glass according to claim 1, which is used for a vehicle.

8. A laminated glass, comprising: a pair of glass sheets; and the interlayer film for a laminated glass according to claim 1 between the glass sheets.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a schematic view illustrating, in a two-layer interlayer film for a laminated glass, a surface on which the ten-point average roughness Rz and the average interval Sm of projections and recesses are measured.

(2) FIG. 2 is a schematic view illustrating, in a three-layer interlayer film for a laminated glass, a surface on which the ten-point average roughness Rz and the average interval Sm of projections and recesses are measured.

(3) FIG. 3(a) is a schematic frontal view of the area where the interlayer film for a laminated glass should satisfy the Rz/Sm specified in the present invention when the interlayer film is used in a vehicular windshield.

(4) FIG. 3(b) is a schematic side view of the area where the interlayer film for a laminated glass should satisfy the Rz/Sm specified in the present invention when the interlayer film is used in a vehicular windshield.

DESCRIPTION OF EMBODIMENTS

(5) Embodiments of the present invention will be described in detail below with reference to examples. The present invention is not limited to these examples.

EXAMPLE 1

(6) (1) Preparation of Resin Composition for Intermediate Layer

(7) Polyvinyl butyral (acetyl group content: 12.0 mol %, butyral group content: 65.0 mol %, hydroxy group content: 23.0 mol %) was obtained by acetalizing polyvinyl alcohol having an average degree of polymerization of 2400 with n-butyraldehyde. To 100 parts by mass of the polyvinyl butyral was added 60 parts by mass of triethylene glycol-di-2-ethylhexanoate (3GO) as a plasticizer. The mixture was sufficiently kneaded with a mixing roll to provide a resin composition for an intermediate layer.

(8) (2) Preparation of Resin Composition for Protective Layer

(9) Polyvinyl butyral (acetyl group content: 1.0 mol %, butyral group content: 69.0 mol %, hydroxy group content: 30.0 mol %) was obtained by acetalizing polyvinyl alcohol having an average degree of polymerization of 1700 with n-butyraldehyde. 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. The mixture was sufficiently kneaded with a mixing roll to provide a resin composition for a protective layer.

(10) (3) Preparation of Interlayer Film for Laminated Glass

(11) The resin composition for an intermediate layer and the resin composition for a protective layer obtained above were co-extruded with a co-extruder to prepare a three-layer interlayer film for a laminated glass in which a layer A (protective layer), a layer B (intermediate layer), and a layer C (protective layer) were laminated in the stated order. The layer A was formed of the resin composition for a protective layer and had a thickness of 350 μm, the layer B was formed of the resin composition for an intermediate layer and had a with a thickness of 100 μm, and the layer C was formed of the resin composition for a protective layer and had a thickness of 350 μm. The co-extruder used had a pressure measuring device installed at the inlet of each gear pump, and the pressure measuring device sent the measured inlet pressure data to a computer on real time. The extruding rate was precisely changed based on the data, whereby the variation range of the inlet pressure of each extruder within 30 seconds was controlled to 0.4% or less.

(12) (4) Impartment of Projections and Recesses

(13) In the first step, a pattern of projections and recesses was randomly transferred to both surfaces of the interlayer film for a laminated glass by the following process. First, random projections and recesses were formed on iron roll surfaces with an abrasive material, and the iron rolls were subjected to vertical grinding. Finer projections and recesses were further formed on planar portions after the grinding, with a finer abrasive material. In this manner, a pair of rolls in the same shape having a coarse main embossed pattern and a fine sub-embossed pattern were obtained. The pair of rolls was used as a device for transferring a pattern of projections and recesses to transfer a random pattern of projections and recesses to both faces 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, and a linear pressure of 50 to 100 kN/m. The shaped interlayer film for a laminated glass had a surface roughness measured based on the ten-point average roughness Rz in conformity with JIS B 0601(1994) of 35 μm. The surface roughness was determined by processing data of a digital signal measured with a surface roughness measuring device (produced by Kosaka Laboratory Ltd., SE1700a). The measurement direction was perpendicular to the engraved lines. Measurement was performed under the conditions of a cut-off value of 2.5 mm, a standard length of 2.5 mm, an evaluation length of 12.5 mm, a tip radius of a probe of 2 μm, a tip angle of 60°, and a measurement speed of 0.5 mm/s.

(14) In the second step, projections and recesses having a groove shape with a continuous bottom (shape of an engraved line) were imparted to a surface of the interlayer film for a laminated glass by the following process.

(15) 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 obtained interlayer film for a laminated glass to which the random pattern of projections and recesses was transferred in the first step was passed through the device for transferring a pattern of projections and recesses, whereby projections and recesses in which recesses having a groove shape with a continuous bottom (shape of an engraved line) were arranged in parallel with one another at equal intervals were imparted to the surface of the layer A of the interlayer film for a laminated glass. The transferring was performed under the conditions of a temperature of the interlayer film for a laminated glass of 75° C., a temperature of the rolls of 130° C., a linear velocity of 10 m/min, a film width of 1.5 m, and a pressure of 500 kPa.

(16) Subsequently, the similar treatment was performed to impart recesses having a groove shape with a continuous bottom (shape of an engraved line) to the surface of the layer C of the interlayer film for a laminated glass, except that the shape of the projections and recesses on a metal roll used was different. Here, the recesses having a groove shape with a continuous bottom (shape of an engraved line) imparted to the surface of the layer A and the recesses having a groove shape with a continuous bottom (shape of an engraved line) imparted to the surface of the layer C were set to form a crossing angle of 10°.

(17) The surface roughness of the resulting interlayer film for a laminated glass determined based on the ten-point average roughness Rz in conformity with JIS B 0601(1994) was 50 μm. The surface roughness was determined by processing data of a digital signal measured with a surface roughness measuring device (produced by Kosaka Laboratory Ltd., SE1700a). The measurement direction was perpendicular to the engraved line. Measurement was performed under the conditions of a cut-off value of 2.5 mm, a standard length of 2.5 mm, an evaluation length of 12.5 mm, a tip radius of a probe of 2 μm, a tip angle of 60°, and a measurement speed of 0.5 mm/s.

(18) (5) Preparation of Laminated Glass

(19) The obtained interlayer film for a laminated glass was sandwiched between two clear glass sheets (30 cm long×30 cm wide×2.5 mm thick) conforming to JIS R3202(1996), and a portion protruding therefrom was cut, whereby a laminated glass structure was prepared. The obtained laminated glass structure was placed into a rubber bag, which was connected to a vacuum suction device. The rubber bag was held under a reduced pressure of −60 kPa (absolute pressure of 16 kPa) for 10 minutes with heating so that the temperature (preliminary pressure-bonding temperature) of the laminated glass structure reached 70° C. Thereafter, the pressure was returned to atmospheric pressure to complete the preliminary pressure-bonding. The preliminarily pressure-bonded laminated glass structure was placed in an autoclave, and held at a temperature of 140° C. and a pressure of 1300 kPa for 10 minutes. Then, 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.

(20) (6) Measurement for Projections and Recesses on Interface

(21) The obtained laminated glass was cooled with liquid nitrogen, so that the interlayer film for a laminated glass was peeled away from the glass. The peeled interlayer film for a laminated glass was cut into a size of 5 cm long×5 cm wide and allowed to stand at a temperature of 25° C. and a humidity of 30% for two hours.

(22) A finger was put between the layers A and B, and the layer A was held with one hand and the layer B with the other hand. The layers were then peeled away from each other with both hands at 1 to 2 cm/s. The layer A after peeling was allowed to stand for two hours at a temperature of 25° C. and a humidity of 30%. Thereafter, the surface of the peeled layer A on the side of the layer B was subjected to the measurement of the ten-point average roughness Rz and the average interval Sm of projections and recesses after the production of the laminated glass in conformity with JIS B 0601(1994) using a high-accuracy profile measurement system (produced by Keyence Corporation, “KS-1100”, model number of head: LT-9510VM). The measurement conditions were as follows: the stage travel rate: 1000 μm/s, the measurement pitch of X-axis: 10 μm, the measurement pitch of Y-axis: 10 μm, and the measuring field: 2.5 cm along the machine direction in the production of the interlayer film for a laminated glass by 1 cm along the direction perpendicular to the machine direction. The obtained data was analyzed with analysis software KS-Analyzer (produced by Keyence Corporation). The line roughness (1994JIS) was measured with the analyzing software using a horizontal line after height smoothing correction (cut-off value: 2.50 mm, simple average: ±12). Each of the Rz and the Sm was measured as the average of three randomly selected points spaced by at least 1 mm in the perpendicular direction of the image. The layer B and the layer C were peeled away from each other in the same manner, and the ten-point average roughness Rz and the average interval Sm of projections and recesses of the surface of the layer C on the side of the layer B were measured. The projections and recesses on the interface before the production of the laminated glass were also measured in the same manner, except that the step of cooling the laminated glass with liquid nitrogen was omitted.

(23) (7) Measurement of Plasticizer Content

(24) The laminated glass produced above was allowed to stand for four weeks at a temperature of 25° C. and a humidity of 30%. The laminated glass was then cooled with liquid nitrogen, so that the interlayer film for a laminated glass was peeled away from the glass. The obtained protective layers and the intermediate layer were cut in the thickness direction, followed by standing for two hours at a temperature of 25° C. and a humidity of 30%. Thereafter, a finger or apparatus was put between one of the protective layers and the intermediate layer, and the layers were peeled away from each other at a temperature of 25° C. and a humidity of 30%. Thus, 10 g of a rectangular specimen was obtained for each of the protective layer and the intermediate layer. The specimens were each subjected to extraction of the plasticizer for 12 hours using a Soxhlet extractor with diethyl ether. The amount of the plasticizer in each specimen was determined to determine the plasticizer content of each of the protective layer and the intermediate layer.

EXAMPLE 2

(25) An interlayer film for a laminated glass and a laminated glass were prepared and projections and recesses on the interface were subjected to measurement in the same manner as in Example 1, except that the variation range of the inlet pressure of each extruder within 30 seconds was controlled to 0.2% or less.

EXAMPLE 3

(26) An interlayer film for a laminated glass and a laminated glass were prepared and projections and recesses on the interface were subjected to measurement in the same manner as in Example 1, except that the second step was omitted.

EXAMPLE 4

(27) An interlayer film for a laminated glass and a laminated glass were prepared in the same manner as in Example 1, except that the variation range of the inlet pressure of each extruder within 30 seconds was controlled to 0.4% or less and that the linear pressure in the first step in the impartment of projections and recesses was changed to 5 to 49.9 kN/m.

EXAMPLE 5

(28) An interlayer film for a laminated glass and a laminated glass were prepared and projections and recesses on the interface were subjected to measurement in the same manner as in Example 4, except that the variation range of the inlet pressure of each extruder within 30 seconds was controlled to 0.2% or less.

EXAMPLE 6

(29) The resin compositions were extruded in the same manner as in Example 2 except for the following changes: The co-extrusion with a co-extruder was performed using a die whose lip had a shape for a lip method, and the lip die had a lip gap of 0.7 to 1.4 mm; the temperature of the resin compositions at the inlet of the die was adjusted to 150° C. to 270° C. and the temperature of the lip die was adjusted to 210° C.; the line speed was 10 m/min; and the variation range of the inlet pressure of each extruder within 30 seconds was controlled to 0.4% or less. An interlayer film for a laminated glass and a laminated glass were prepared and projections and recesses on the interface were subjected to measurement in the same manner as in Example 2 except that the first step of the impartment of projections and recesses was omitted.

EXAMPLE 7

(30) An interlayer film for a laminated glass and a laminated glass were prepared and projections and recesses were subjected to measurement in the same manner as in Example 6, except that the step 2 was omitted.

EXAMPLE 8

(31) The interlayer film for a laminated glass of Example 4 was heated in a gear oven such that the film surface temperature reached 120° C., and stretched at 5 cm to 15 cm/s to 1.3 times the length before the heating. The film was fixed with jigs to maintain the 1.3-times stretch and then cooled with 25° C. water. The cooled film, while being fixed, was allowed to stand for 12 hours at a temperature of 25° C. and a humidity of 30%, so that the film was dried. After the drying, a laminated glass was prepared and projections and recesses on the interface were subjected to measurement in the same manner as in Example 1.

EXAMPLE 9

(32) A laminated glass was prepared and projections and recesses on the interface were subjected to measurement in the same manner as in Example 8, except that the interlayer film for a laminated glass of Example 7 was used instead of the interlayer film for a laminated glass of Example 4.

EXAMPLE 10

(33) The interlayer film for a laminated glass of Example 3 was heated in a gear oven such that the film surface temperature reached 120° C., and stretched at 5 cm to 15 cm/s to 1.3 times the length before the heating. The film was fixed with jigs to maintain the 1.3-times stretch and then cooled with 25° C. water. The cooled film, while being fixed, was allowed to stand for 12 hours at a temperature of 25° C. and a humidity of 30%, so that the film was dried. After the drying, a laminated glass was prepared and projections and recesses on the interface were subjected to measurement in the same manner as in Example 1.

EXAMPLES 11 AND 12

(34) An interlayer film for a laminated glass and a laminated glass were prepared and projections and recesses were subjected to measurement in the same manner as in Example 3, except that the acetyl group content, the butyral group content, and the hydroxy group content of the polyvinyl butyral used for the intermediate layer were changed.

EXAMPLES 13 AND 14

(35) An interlayer film for a laminated glass and a laminated glass were prepared and projections and recesses were subjected to measurement in the same manner as in Example 6, except that the acetyl group content, the butyral group content, and the hydroxy group content of the polyvinyl butyrals used for the protective layer and the intermediate layer were changed, and that the metal roll used in the step 2 having a surface milled with a triangular oblique line-type mill was changed.

EXAMPLES 15 AND 16

(36) An interlayer film for a laminated glass and a laminated glass were prepared and projections and recesses were subjected to measurement in the same manner as in Example 6, except that the acetyl group content, the butyral group content, and the hydroxy group content of the polyvinyl butyrals used for the protective layer and the intermediate layer were changed, and that the temperature of the lip die was adjusted to 195° C. to 209° C.

COMPARATIVE EXAMPLE 1

(37) An interlayer film for a laminated glass and a laminated glass were prepared and projections and recesses were subjected to measurement in the same manner as in Example 1, except that the variation in the inlet pressure was not controlled during the co-extrusion with a co-extruder.

(38) Measurement with the pressure measuring device installed at the inlet of each gear pump showed that the variation range of the inlet pressure of each extruder within 30 seconds was 1.0% or more.

COMPARATIVE EXAMPLE 2

(39) An interlayer film for a laminated glass and a laminated glass were prepared and projections and recesses were subjected to measurement in the same manner as in Example 1, except that the variation range of the inlet pressure of each extruder within 30 seconds was controlled to 0.8% or less.

COMPARATIVE EXAMPLE 3

(40) An interlayer film for a laminated glass and a laminated glass were prepared and projections and recesses were subjected to measurement in the same manner as in Example 6, except that the temperature of the resin compositions at the inlet of the die was changed to 100° C. to 145° C., and that the variation in the inlet pressure was not controlled. Measurement with the pressure measuring device installed at the inlet of each gear pump showed that the variation range of the inlet pressure of each extruder within 30 seconds was 1.0% or more.

(41) (Evaluation)

(42) The laminated glasses obtained in the examples and comparative examples were subjected to evaluation of the occurrence of optical distortion in the following manner. The results are shown in Tables 1 and 2.

(43) In Tables 1 and 2, regarding the polyvinyl butyrals used in the examples and comparative examples, the acetyl group content was abbreviated as Ac, the butyral group content was abbreviated as Bu, and the hydroxy group content was abbreviated as OH.

(44) (1) Evaluation of Optical Distortion (Visual Evaluation)

(45) A fluorescent lamp (FL32S.D, Panasonic Corporation) was set at a position 7 m away from the observer. The obtained laminated glass was placed at a position on a straight line connecting the fluorescent lamp and the observer and 40 cm distant from the observer such that the laminated glass was inclined at an angle of 20° to a horizontal plane. A rating “× (Poor)” was given when the fluorescent lamp appeared distorted through the laminated glass. A rating “◯ (Good)” was given when the fluorescent lamp did not appear distorted.

(46) The optical distortion was evaluated at 25° C. and 80° C.

(47) (2) Evaluation of Optical Distortion Value

(48) The optical distortion value was determined using an optical distortion inspecting device disclosed in JP H07-306152 A. The device includes: a light source unit which emits illumination light toward a light-transmitting object to be inspected; a projection plane where the illumination light having passed through the object to be inspected is projected; an image inputting portion for generating a grayscale image by capturing the projection plane; and an image processing portion for determining the presence or absence of distortion based on the variation in the gray level of the grayscale image generated by the image inputting portion. Specifically, upon evaluation on the optical distortion by using EYE DICHO-COOL HALOGEN (15 V 100 W) produced by Iwasaki Electric Co., Ltd. as a light source, the illuminance of the light source, the angle of the screen where an optical distortion image is projected, and the angle of the camera were adjusted in such a manner that a laminated glass including a single layer film having a visible light transmittance in conformity with JIS R 3211(1988) (value for Y under standard illuminant A, A-Y (380 to 780 nm)) of 88% (“U4100” produced by Hitachi High-Technologies Corporation was used) had an optical distortion value of 1.14 and that the optical distortion value in a state of including no glass was adjusted to 1.30. The optical distortion was evaluated using a laminated glass prepared such that the above visible light transmittance was 87% to 89% under the conditions of a measurement atmosphere temperature of 23° C. and a laminated glass temperature of 25° C. and 80° C. The evaluation was performed 24 hours after the autoclave treatment. As the optical distortion values, values in the lengthwise direction and in the width direction can be calculated. In the present case, the smaller value of the two was employed as the optical distortion value. The thermometer used was a contact-type thermometer.

(49) TABLE-US-00001 TABLE 1 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Roll Roll Roll Roll Roll Lip Lip Roll Lip Roll embossing embossing embossing embossing embossing embossing embossing embossing embossing embossing Surface embossing method method method method method method method method method method method Stretch 100% 100% 100% 100% 100% 100% 100% 130% 130% 130% Variation range of inlet 0.4 0.2 0.4 0.4 0.2 0.4 0.4 0.4 0.4 0.4 pressure in co-extrusion (%) Resin composition Bu mol % 69.0 69.0 69.0 69.0 69.0 69.0 69.0 69.0 69.0 69.0 For protective layer OH mol % 30.0 30.0 30.0 30.0 30.0 30.0 30.0 30.0 30.0 30.0 Ac mol % 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Plasticizer content phr 37 37 37 37 37 37 37 37 37 37 (parts) after glass production Resin composition Bu mol % 65.0 65.0 65.0 65.0 65.0 65.0 65.0 65.0 65.0 65.0 for intermediate layer OH mol % 23.0 23.0 23.0 23.0 23.0 23.0 23.0 23.0 23.0 23.0 Ac mol % 12.0 12.0 12.0 12.0 12.0 12.0 12.0 12.0 12.0 12.0 Plasticizer content phr 70 70 70 70 70 70 70 70 70 70 (parts) after glass production Projections and recesses on Ten-point average 50 47 35 33 33 35 20 29 14 22 protective layer surface roughness Rz (μm) Projections and recesses on Ten-point average 1.12 0.89 1.05 0.67 0.59 0.88 0.69 0.71 1.10 1.20 layer B-side surface of roughness Rz (μm) layer A peeled before Average interval 1599 1195 1299 1325 875 1451 1198 987 1059 1150 laminated glass production of projections and recesses Sm (μm) Rz/Sm 0.00070 0.00074 0.00081 0.00051 0.00067 0.00061 0.00058 0.00072 0.00104 0.00104 Projections and recesses on Ten-point average 1.77 0.92 1.32 0.68 0.6 1.40 0.84 0.79 1.37 1.85 layer B-side surface of roughness Rz (μm) layer A peeled after Average interval 1230 921 819 692 632 1364 871 782 895 1057 laminated glass production of projections and recesses Sm (μm) Rz/Sm 0.00146 0.00100 0.00164 0.00098 0.00095 0.00102 0.00105 0.00108 0.00162 0.00175 Evaluation Optical distortion 25° C. ∘ ∘ ∘ ∘ ∘ ∘ ∘ ∘ ∘ ∘ evaluation 80° C. ∘ ∘ ∘ ∘ ∘ ∘ ∘ ∘ ∘ ∘ (visual evaluation) Optical distortion 25° C. 1.8 1.35 1.66 1.25 1.21 1.3 1.28 1.3 1.4 2.16 value 80° C. 1.93 1.38 1.75 1.26 1.22 1.32 1.3 1.33 1.45 2.35

(50) TABLE-US-00002 TABLE 2 Comparative Comparative Comparative Example 11 Example 12 Example 13 Example 14 Example 15 Example 16 Example 1 Example 2 Example 3 Roll Roll Lip Lip Lip Lip Roll Roll Lip embossing embossing embossing embossing embossing embossing embossing embossing embossing Surface embossing method method method method method method method method method method Stretch 100% 100% 100% 100% 100% 100% 100% 100% 100% Variation range of the inlet 0.4 0.4 0.4 0.4 0.4 0.4 1.0 0.8 1.0 pressure in co-extrusion (%) Resin composition Bu mol % 69.0 69.0 69.8 66.4 70.4 66.4 69.0 69.0 69.0 for protective OH mol % 30.0 30.0 29.1 32.5 28.6 32.5 30.0 30.0 30.0 layer Ac mol % 1.0 1.0 1.1 1.1 1.0 1.1 1.0 1.0 1.0 Plasticizer phr 37 37 37 37 37 37 37 37 37 content (parts) after glass production Resin composition Bu mol % 57.0 67.5 80.6 68.1 80.3 68.1 65.0 65.0 65.0 for intermediate OH mol % 20.0 20.5 18.8 24.3 18.6 24.3 23.0 23.0 23.0 layer Ac mol % 23.0 12.0 0.6 7.6 1.1 7.6 12.0 12.0 12.0 Plasticizer phr 72 72 70 70 70 70 70 70 70 content (parts) after glass production Projections and Ten-point average 35 35 60 25 50 45 50 50 35 recesses on protective roughness Rz (μm) layer surface Projections and Ten-point average 1.03 0.98 1.20 0.67 1.45 1.15 1.45 1.30 1.97 recesses on roughness Rz (μm) layer B-side Average interval 1175 1229 1842 1217 2625 1256 1268 1138 1625 surface of layer of projections A peeled before and recesses Sm (μm) laminated glass Rz/Sm 0.00088 0.00080 0.00065 0.00055 0.00055 0.00092 0.00114 0.00114 0.00121 production Projections Ten-point average 1.20 1.17 1.70 0.87 1.65 1.57 2.54 1.97 4.46 and recesses roughness Rz (μm) on layer B-side Average interval 850 825 1674 871 1950 1047 1312 1037 1402 surface of layer of projections A peeled after and recesses Sm (μm) laminated glass Rz/Sm 0.00141 0.00142 0.00102 0.00100 0.00085 0.00150 0.00215 0.00190 0.00318 production Evaluation Optical distortion 25° C. ∘ ∘ ∘ ∘ ∘ ∘ ∘ ∘ ∘ evaluation (visual 80° C. ∘ ∘ ∘ ∘ ∘ ∘ x x x evaluation) Optical distortion 25° C. 1.65 1.58 1.55 1.25 1.35 1.7 3.35 2.54 2.51 value 80° C. 1.9 1.81 1.7 1.31 1.4 1.81 3.94 2.95 2.93

INDUSTRIAL APPLICABILITY

(51) The present invention provides an interlayer film for a laminated glass which has a multilayer structure including two or more resin layers laminated together and can prevent optical distortion even at high temperatures. The present invention also provides a laminated glass including the interlayer film for a laminated glass and a method of producing the interlayer film for a laminated glass.

REFERENCE SIGNS LIST

(52) 1 Clear glass 10 Resin layer 20 Resin layer 21 Surface of resin layer 20 on the side having been in contact with resin layer 10 30 Resin layer 40 Vehicle 41 Laminated glass 42 Hood 43 Area where Rz/Sm according to the present invention should be satisfied