LAMINATED-GLASS INTERLAYER, AND LAMINATED GLASS

Abstract

The present invention provides an interlayer film for a laminated glass capable of providing a laminated glass that reduces the occurrence of optical distortion, a laminated glass including the interlayer film for a laminated glass, and a method for producing the interlayer film for a laminated glass. Provided is an interlayer film for a laminated glass, having a maximum thickness curvature in a width direction of the interlayer film for a laminated glass of 0.010 m.sup.−1 or less.

Claims

1. An interlayer film for a laminated glass, having a maximum thickness curvature in a width direction of the interlayer film for a laminated glass of 0.010 m.sup.−1 or less.

2. The interlayer film for a laminated glass according to claim 1, having a maximum thickness difference in the width direction of 15 μm or less as measured in a 150-mm section of the interlayer film for a laminated glass.

3. 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, the interlayer film for a laminated glass in the laminated glass having a maximum thickness curvature in the width direction of 0.004 m.sup.−1 or less.

4. 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, the laminated glass having a maximum thickness curvature in a width direction of the laminated glass of 0.010 m.sup.−1 or less.

5. The laminated glass according to claim 4, wherein the maximum thickness curvature of the laminated glass in the width direction of the laminated glass is 0.003 m.sup.−1 or less.

6. A method for producing the interlayer film for a laminated glass according to claim 1, comprising a step of imparting protrusions and recesses to a surface of the interlayer film for a laminated glass while extrusion molding a raw material resin composition through an extruder, the step being performed by a lip method, the extruder including a die that has a straightness of 4 μm or less over 1,000 mm in a width direction of the die and includes protrusions and recesses of a size of 2 μm or smaller in an 80-mm section in the width direction.

7. The method for producing an interlayer film for a laminated glass according to claim 6, wherein press rolls having a cylindricity of 4 μm or less are used.

8. A laminated glass including: a pair of glass plates; and the interlayer film for a laminated glass according to claim 2 interposed between the pair of glass plates, the interlayer film for a laminated glass in the laminated glass having a maximum thickness curvature in the width direction of 0.004 m.sup.−1 or less.

9. A laminated glass including: a pair of glass plates; and the interlayer film for a laminated glass according to claim 2 interposed between the pair of glass plates, the laminated glass having a maximum thickness curvature in a width direction of the laminated glass of 0.010 m.sup.−1 or less.

10. The laminated glass according to claim 9, wherein the maximum thickness curvature of the laminated glass in the width direction of the laminated glass is 0.003 m.sup.−1 or less.

11. A method for producing the interlayer film for a laminated glass according to claim 2, comprising a step of imparting protrusions and recesses to a surface of the interlayer film for a laminated glass while extrusion molding a raw material resin composition through an extruder, the step being performed by a lip method, the extruder including a die that has a straightness of 4 μm or less over 1,000 mm in a width direction of the die and includes protrusions and recesses of a size of 2 μm or smaller in an 80-mm section in the width direction.

12. The method for producing an interlayer film for a laminated glass according to claim 11, wherein press rolls having a cylindricity of 4 μm or less are used.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0088] FIG. 1 shows schematic views explaining methods for measuring the maximum thickness curvature and maximum thickness difference of an interlayer film for a laminated glass in the width direction.

[0089] FIG. 2 shows a schematic view explaining a distortion test in the evaluation of examples and comparative examples.

DESCRIPTION OF EMBODIMENTS

[0090] Embodiments of the present invention are specifically described in the following with reference to, but not limited to, examples.

Example 1

(1) Production of Interlayer Film for Laminated Glass

[0091] To 100 parts by weight of polyvinyl butyral were added 40 parts by weight of a plasticizer, 0.5 parts by weight of an UV blocking agent, and 0.5 parts by weight of an antioxidant. The materials were sufficiently kneaded in a mixing roll, whereby a resin composition was prepared. The polyvinyl butyral had a hydroxy group content of 30 mol %, an acetyl group content of 1 mol %, a butyral group content of 69 mol %, and an average degree of polymerization of 1,700. The plasticizer used was triethylene glycol-di-2-ethylhexanoate (3GO). The UV blocking agent used was 2-(2′-hydroxy-3′-t-butyl-5-methylphenyl)-5-chlorobenzotriazole (produced by BASF, “Tinuvin 326”). The antioxidant used was 2,6-di-t-butyl-p-cresol (BHT).

[0092] The obtained resin composition was extruded through an extruder into a single-layer interlayer film for a laminated glass having a width of 100 cm, and the interlayer film was wound into a roll.

[0093] The die of the extruder used in the lip method at this time had a straightness of 4 μm over 1,000 mm in the width direction and included protrusions and recesses of a size of 2 μm in an 80-mm section in the width direction. The press rolls used had a cylindricity of 3 μm.

[0094] The interlayer film for a laminated glass was drawn out from the obtained roll and cut at a position of 70 cm in the machine direction, whereby a test sample having a size of 70 cm×film width (1 m) was obtained. The test sample was left to stand on a flat surface at 20° C. and 30 RH % or lower for 24 hours before subjected to measurement. After standing, the thickness was measured continuously from one end to the other end of the test sample in the width direction at a rate of 1.5 m/min using a micrometer (KG601B-type wide-range electronic micrometer produced by Anritsu Corporation). Thus, the thickness was recorded at a 0.4 mm pitch. The thickness was measured at 20° C. and 30 RH % or lower. Next, based on the obtained thickness data in the width direction, the maximum thickness curvature of the interlayer film for a laminated glass in the width direction was calculated. First, based on the obtained thickness data in the width direction, the measured data (raw data output at intervals of 0.4 mm) was subjected to 40-mm-section simple moving averaging while moving the section from an end of the measurement site by 0.4 mm at a time. After the simple moving averaging, a cubic polynomial approximate expression was obtained by the least square method in each 30-mm section while shifting the initial value by 0.4 mm at a time. The curvature at the center of the section was calculated using a polynominally approximated function f(x). The curvature was calculated by the above formula (1). Then, the maximum value of the curvatures calculated in the sections was determined, and taken as the maximum thickness curvature in the width direction of the test sample.

[0095] Separately, based on the obtained thickness data in the width direction, the maximum thickness difference of the interlayer film for a laminated glass in the width direction was calculated. Specifically, based on the obtained thickness data in the width direction, the maximum difference (difference between a point having the maximum thickness and a point having a minimum thickness) was determined in each 150-mm section while moving the section from an end of the measurement site by 0.4 mm at a time. The maximum difference in each 150-mm section in the width direction was calculated, and the largest of the maximum differences was taken as the maximum thickness difference of the text sample.

(2) Production of Laminated Glass

[0096] The interlayer film for a laminated glass was drawn out from the obtained roll and cut at a position of 70 cm in the machine direction, whereby an interlayer film for a laminated glass having a size of 70 cm×film width (1 m) was obtained. The interlayer film for a laminated glass was left to stand on a flat surface at 20° C. and 30 RH % or lower for 24 hours, and then used to produce a laminated glass.

[0097] The interlayer film for a laminated glass was interposed between two glass plates (each having a thickness of 1.7 mm, a width of 750 mm, and a length of 500 mm) such that the width direction of the interlayer film was in parallel with the crosswise direction of the glass plates, that the machine direction of the interlayer film for a laminated glass was in parallel with the lengthwise direction of the glass plates, and that the center of the interlayer film for a laminated glass was positioned at the center of the glass plates. The interlayer film for a laminated glass protruding from the glass plates was cut off, whereby a laminate was obtained.

[0098] The obtained laminate was conveyed on a conveyer through a heating zone so that the laminate was heated, and then passed between nip rolls to squeeze out the air remaining between the glass and the interlayer film while the laminate was thermally pressure-bonded. The air between the interlayer film for a laminated glass and the glass was thus reduced, whereby the laminate was preliminarily pressure bonded. The laminate after the preliminary pressure bonding was subjected to final pressure bonding in an autoclave at high temperature and high pressure, whereby a laminated glass was obtained.

[0099] The heating temperature in the heating zone was 220° C. The glass surface temperature after passing through the heating zone was 80° C. The heating time was one minute or shorter, and the nip pressure was 3 kg/cm.sup.2 or lower. The temperature inside the autoclave was 140° C. at maximum, and the maximum pressure was 14 kg/cm.sup.2. The heating and pressurizing time in the autoclave was at most 30 minutes.

[0100] For the obtained laminated glass, in the same manner as in the above shape evaluation of the interlayer film for a laminated glass, calculations were performed to determine the maximum thickness curvature of the laminated glass in the width direction and the maximum thickness curvature of the interlayer film for a laminated glass in the laminated glass in the width direction.

Comparative Example 1

[0101] An interlayer film for a laminated glass was obtained as in Example 1 and wound into a roll, except that the die of the extruder used in the lip method had a straightness of 7 μm over 1,000 mm in the width direction and included protrusions and recesses of a size of 2 μm in an 80-mm section in the width direction, and that the press rolls used had a cylindricity of 5 μm. A laminated glass was also produced as in Example 1.

Comparative Example 2

[0102] An interlayer film for a laminated glass was obtained as in Example 1 and wound into a roll, except that the die of the extruder used in the lip method had a straightness of 8 μm over 1,000 mm in the width direction and included protrusions and recesses of a size of 2 μm in an 80-mm section in the width direction, and that the press rolls used had a cylindricity of 6 μm. A laminated glass was also produced as in Example 1, and the maximum thickness curvature of the laminated glass in the width direction was calculated.

Example 2

(1) Preparation of Resin Composition for Protective Layer

[0103] To 100 parts by weight of a polyvinyl butyral resin were added 38.8 parts by weight of a plasticizer, 0.5 parts by weight of an UV blocking agent, and 0.5 parts by weight of an antioxidant. The materials were sufficiently kneaded in a mixing roll, whereby a protective layer resin composition was prepared. The polyvinyl butyral had a hydroxy group content of 30 mol %, an acetyl group content of 1 mol %, a butyral group content of 69 mol %, and an average degree of polymerization of 1,700. The UV blocking agent used was “Tinuvin 326” produced by BASF. The plasticizer used was triethylene glycol-di-2-ethylhexanoate (3GO). The UV blocking agent used was 2-(2′-hydroxy-3′-t-butyl-5-methylphenyl)-5-chlorobenzotriazole (produced by BASF, “Tinuvin 326”). The antioxidant used was 2,6-di-t-butyl-p-cresol (BHT).

(2) Preparation of Resin Composition for Sound Insulation Layer

[0104] To 100 parts by weight of a polyvinyl butyral resin was added 68.8 parts by weight of a plasticizer. The materials were sufficiently kneaded in a mixing roll, whereby a resin composition for a sound insulation layer was prepared. The polyvinyl butyral had a hydroxy group content of 23.3 mol %, an acetyl group content of 12.5 mol %, a butyral group content of 64.2 mol %, and an average degree of polymerization of 2,300. The plasticizer used was triethylene glycol-di-2-ethylhexanoate (3GO).

(3) Production of Interlayer Film for Laminated Glass

[0105] The resin composition for a sound insulation layer and the resin composition for a protective layer were co-extruded into a three-layer structure interlayer film for a laminated glass which had a width of 100 cm and in which a protective layer (average thickness: 350 μm), a sound insulation layer (average thickness: 100 μm), and a protective layer (average thickness: 350 μm) were laminated in the stated order in the thickness direction. The interlayer film was wound into a roll. The die of the extruder used in the lip method at this time had a straightness of 4 μm over 1,000 mm in the width direction and included protrusions and recesses of a size of 2 μm in an 80-mm section in the width direction. The press rolls used had a cylindricity of 4 μm.

[0106] For the obtained interlayer film for a laminated glass, calculations were performed as in Example 1 to determine the average thickness in the width direction, the maximum thickness curvature in the width direction, and the maximum thickness difference in the width direction. A laminated glass was also produced as in Example 1, and calculations were performed to determine the maximum thickness curvature of the laminated glass in the width direction and the maximum thickness curvature of the interlayer film for a laminated glass in the laminated glass in the width direction.

Example 3

[0107] An interlayer film for a laminated glass was produced as in Example 2, except that the extrusion conditions were set such that the interlayer film for a laminated glass obtained after imparting protrusions and recesses satisfied the following: each protective layer has a rectangular cross section in the thickness direction that has a maximum thickness of 409 μm and a minimum thickness of 329 μm; the sound insulation layer has a rectangular cross section in the thickness direction that has a maximum thickness of 129 μm and a minimum thickness of 98 μm; and the entire interlayer film has a rectangular cross section in the thickness direction that has an average film thickness of 825 μm. For the interlayer film for a laminated glass, calculations were performed to determine the average thickness in the width direction, the maximum thickness curvature in the width direction, and the maximum thickness difference in the width direction. A laminated glass was also produced as in Example 1, and calculations were performed to determine the maximum thickness curvature of the laminated glass in the width direction and the maximum thickness curvature of the interlayer film for a laminated glass in the laminated glass in the width direction.

Example 4

(Production of Wedge-Shaped Interlayer Film for Laminated Glass)

[0108] A resin composition for a sound insulation layer and a resin composition for a protective layer, both obtained as in Example 2, were co-extruded through a co-extruder into a three-layer structure interlayer film for a laminated glass in which a protective layer, a sound insulation layer, and a protective layer were laminated in the stated order in the thickness direction. The interlayer film was wound into a roll.

[0109] The extrusion conditions were set such that the interlayer film for a laminated glass obtained after imparting protrusions and recesses satisfied the following: each protective layer has a wedge-shaped cross section in the thickness direction that has a maximum thickness of 790 μm and a minimum thickness of 280 μm; the sound insulation layer has a wedge-shaped cross section in the thickness direction that has a maximum thickness of 180 μm and a minimum thickness of 90 μm; and the entire interlayer film has a wedge-shaped cross section in the thickness direction that has a maximum thickness of 1,440 μm and a minimum thickness of 700 μm. The extrusion conditions were set such that the entire interlayer film had a width of 100 cm.

[0110] At this time, the lip die temperature was adjusted to have a gradient within a range of 100° C. to 280° C. in the width direction such that the temperature at the end on the thinner side of the entire interlayer film was lower and the temperature at the end on the thicker side of the entire interlayer film was higher. The lip die was adjusted to have a lip gap within a range of 1.0 to 4.0 mm. The speed difference between rolls for carrying the resin film ejected from the lip die before winding was adjusted to 15% or less. The first roll for carrying the resin film ejected from the die was positioned lower and more forward in the machine direction than the die. The extrusion amount from the extruder was set to 700 kg/h and the speed of the first roll for carrying the resin film was set to 7 m/min.

[0111] The die of the extruder used in the lip method had a straightness of 4 μm over 1,000 mm in the width direction and included protrusions and recesses of a size of 2 μm in an 80-mm section in the width direction. The press rolls used had a cylindricity of 3 μm.

[0112] For the obtained interlayer film for a laminated glass, calculations were performed as in Example 1 to determine the average thickness in the width direction, the maximum thickness curvature in the width direction, and the maximum thickness difference in the width direction. A laminated glass was also produced as in Example 1, and calculations were performed to determine the maximum thickness curvature of the laminated glass in the width direction and the maximum thickness curvature of the interlayer film for a laminated glass in the laminated glass in the width direction.

Example 5

(1) Preparation of Resin Composition for Color Layer

[0113] To 100 parts by weight of a polyvinyl butyral resin were added 38.8 parts by weight of a plasticizer, 0.5 parts by weight of an UV blocking agent, and 0.5 parts by weight of an antioxidant. The materials were sufficiently kneaded in a mixing roll, whereby a resin composition was prepared. The polyvinyl butyral had a hydroxy group content of 30 mol %, an acetyl group content of 1 mol %, a butyral group content of 69 mol %, and an average degree of polymerization of 1,700. The plasticizer used was triethylene glycol-di-2-ethylhexanoate (3GO). The UV blocking agent used was 2-(2′-hydroxy-3′-t-butyl-5-methylphenyl)-5-chlorobenzotriazole (produced by BASF, “Tinuvin 326”). The antioxidant used was 2,6-di-t-butyl-p-cresol (BHT).

[0114] The obtained composition was mixed with carbon black as a colorant and sufficiently kneaded in a mixing roll, whereby a resin composition for a color layer was obtained. The amount of the colorant added was 0.260% by weight in 100% by weight of the color layer.

(2) Production of Interlayer Film for Laminated Glass

[0115] The obtained resin composition for a color layer was co-extruded with a resin composition for a sound insulation layer and a resin composition for a protective layer, both obtained as in Example 2, through a co-extruder into a five-layer structure interlayer film for a laminated glass in which a protective layer, a color layer, a protective layer, a sound insulation layer, and a protective layer were laminated in the stated order in the thickness direction. The interlayer film was wounded into a roll.

[0116] The extrusion conditions were set such that the interlayer film for a laminated glass obtained after imparting protrusions and recesses satisfied the following: each protective layer and the color layer has a rectangular cross section in the thickness direction that has a maximum thickness of 423 μm and a minimum thickness of 322 μm; the sound insulation layer has a rectangular cross section in the thickness direction that has a maximum thickness of 123 μm and a minimum thickness of 96 μm; and the entire interlayer film has a rectangular cross section in the thickness direction that has an average film thickness of 810 μm.

[0117] At this time, the lip die temperature was adjusted to have a gradient within a range of 100° C. to 280° C. in the width direction such that the temperature at the end on the thinner side of the entire interlayer film was lower and the temperature at the end on the thicker side of the entire interlayer film was higher. The lip die was adjusted to have a lip gap within a range of 1.0 to 4.0 mm. The speed difference between rolls for carrying the resin film ejected from the lip die before winding was adjusted to 15% or less. The first roll for carrying the resin film ejected from the die was positioned lower and more forward in the machine direction than the die. The extrusion amount from the extruder was set to 700 kg/h and the speed of the first roll for carrying the resin film was set to 7 m/min.

[0118] The die of the extruder used in the lip method at this time had a straightness of 4 μm over 1,000 mm in the width direction and included protrusions and recesses of a size of 2 μm in an 80-mm section in the width direction. The press rolls used had a cylindricity of 3 μm.

[0119] For the obtained interlayer film for a laminated glass, calculations were performed as in Example 1 to determine the average thickness in the width direction, the maximum thickness curvature in the width direction, and the maximum thickness difference in the width direction. A laminated glass was also produced as in Example 1, and calculations were performed to determine the maximum thickness curvature of the laminated glass in the width direction and the maximum thickness curvature of the interlayer film for a laminated glass in the laminated glass in the width direction.

Comparative Example 3

[0120] An interlayer film for a laminated glass was prepared as in Example 2 and wound into a roll, except that the die of the extruder used in the lip method had a straightness of 10 μm over 1,000 mm in the width direction and included protrusions and recesses of a size of 2 μm in an 80-mm section in the width direction, and that the press rolls used had a cylindricity of 6 μm. A laminated glass was also produced as in Example 2.

Comparative Example 4

[0121] An interlayer film for a laminated glass was prepared as in Example 2 and wound into a roll, except that the die of the extruder used in the lip method had a straightness of 11 μm over 1,000 mm in the width direction and included protrusions and recesses of a size of 2 μm in an 80-mm section in the width direction, and that the press rolls used had a cylindricity of 8 μm. A laminated glass was also produced as in Example 2.

(Evaluation)

[0122] The interlayer films for a laminated glass obtained in the examples and the comparative examples were evaluated as follows. Table 1 shows the results.

(1) Production of Sample Laminated Glass

[0123] The interlayer film for a laminated glass was drawn out from the obtained roll and cut at a position of 70 cm in the machine direction, whereby a test sample having a size of 70 cm×film width (1 m) was obtained. The interlayer film for a laminated glass was left to stand on a flat surface at 20° C. and 30 RH % or lower for 24 hours, and then used to produce a laminated glass.

[0124] The interlayer film for a laminated glass was interposed between two glass plates (each having a thickness of 2 mm, a width of 750 mm, and a length of 500 mm) such that the width direction of the interlayer film was in parallel with the crosswise direction of the glass plates, that the machine direction of the interlayer film for a laminated glass was in parallel with the lengthwise direction of the glass plates, and that the center of the interlayer film for a laminated glass was positioned at the center of the glass plates. The interlayer film for a laminated glass protruding from the glass plates was cut off, whereby a laminate was obtained.

[0125] The obtained laminate was conveyed on a conveyer through a heating zone so that the laminate was heated, and then passed between nip rolls to squeeze out the air remaining between the glass and the interlayer film while the laminate was thermally pressure-bonded. The air between the interlayer film for a laminated glass and the glass was thus reduced, whereby the laminate was preliminarily pressure bonded. The laminate after the preliminary pressure bonding was subjected to final pressure bonding in an autoclave at high temperature and high pressure, whereby a laminated glass was obtained.

[0126] The heating temperature in the heating zone was 220° C. The glass surface temperature after passing through the heating zone was 80° C. The heating time was one minute, and the nip pressure was 3 kg/cm.sup.2 or lower. The temperature inside the autoclave was 140° C. at maximum, and the pressure was 14 kg/cm.sup.2. The heating and pressurizing time in the autoclave was at most 30 minutes.

(2) Distortion Test

[0127] A distortion test was performed using the obtained sample laminated glass.

[0128] FIG. 2 shows a schematic view explaining the distortion test. Specifically, in a darkroom, a light source 5 (produced by Nippon Gijutsu Center Co., Ltd., S-Light SA160), a laminated glass 6, and a screen 7 were arranged in a straight line in the stated order such that the light source 5 and the laminated glass 6 were horizontally spaced by 3,000 mm and the laminated glass 6 and the screen 7 were horizontally spaced by 1,500 mm. The height of the light source 5 was 600 mm, and the angle of the light beam was 20° upward from the horizontal. The height of the laminated glass 6 at the lowest point was 900 mm. The laminated glass 6 was at an angle of 18° such that the side adjacent to the screen was higher, and placed such that the width direction of the interlayer film for a laminated glass was inclined from the light source toward the screen. The angle of the screen 7 was vertical. The screen was white and generated no shadow due to its surface irregularities.

[0129] A transmission projection image projected on the screen 7 at the above state was subjected to imaging with a camera 8 (produced by FUJIFILM Corporation, FINEPIX F900EXR). The measurement conditions were as follows: aperture f/5.9, exposure time ⅛ s, ISO800, focal length 42 mm, no flash, image size 4,608×3,456 pixels. The size of the captured image was reduced to 640×640 pixels, and 8-bit gray scaling was performed.

[0130] Then, the gray scale image was output to a text file. Thirty five sections were continuously selected at intervals of 10 pixels in the vertical direction of the projection image. A simple moving average (25 pixels) in the vertical direction was determined for each section. This was taken as the base luminance and subtracted from the section, whereby slope correction was performed. Further, for luminance value smoothing, simple moving averaging (5 pixels) was performed for each section. After a variance value between 11 pixels was calculated in the vertical direction, the maximum value of all the variance values of the 35 sections was calculated. The smaller the maximum value of luminance variance, the better the laminated glass can reduce distortion.

TABLE-US-00001 TABLE 1 Shape of entire interlayer film for laminated glass Maximum Maximum thickness thickness curvature difference Sound insulation layer Average in width in width Maximum Minimum thickness direction direction thickness thickness (μm) Structure Cross section (m.sup.−1) (μm) (μm) (μm) Cross section Example 1 825 Single layer Rectanglular 0.007 15 — — — shape Example 2 796 Protective layer/ Rectanglular 0.010 18 114 102  Rectanglular Sound insulation layer/ shape shape Protective layer Example 3 825 Protective layer/ Rectanglular 0.008 26 129 98 Rectanglular Sound insulation layer/ shape shape Protective layer Example 4 1111 Protective layer/ Wedge shape 0.007 14 180 90 Wedge shape Sound insulation layer/ Protective layer Example 5 810 Protective layer/ Rectanglular 0.009 13 123 96 Rectanglular Color layer/ shape shape Protective layer/ Sound insulation layer/ Protective layer Comparative 801 Single layer Rectanglular 0.012 13 — — — Example 1 shape Comparative 842 Single layer Rectanglular 0.014 16 — — — Example 2 shape Comparative 801 Protective layer/ Rectanglular 0.014 19 129 98 Rectanglular Example 3 Sound insulation layer/ shape shape Protective layer Comparative 754 Protective layer/ Rectanglular 0.017 18 116 99 Rectanglular Example 4 Sound insulation layer/ shape shape Protective layer Interlayer film for laminated glass in Laminated laminated glass glass Maximum Maximum thickness thickness Protective layer curvature curvature Distortion Maximum Minimum in width in width Maximum thickness thickness direction direction luminance (μm) (μm) Cross section (m.sup.−1) (m.sup.−1) variance Example 1 — — — 0.002 0.002 9.3 Example 2 436 328 Rectanglular 0.003 0.003 9.7 shape Example 3 409 329 Rectanglular 0.003 0.003 9.4 shape Example 4 790 280 Wedge shape 0.002 0.002 7.4 Example 5 423 322 Rectanglular 0.003 0.003 10.0 shape Comparative — — — 0.004 0.004 14.6 Example 1 Comparative — — — 0.005 0.005 15.9 Example 2 Comparative 409 329 Rectanglular 0.005 0.005 14.4 Example 3 shape Comparative 395 340 Rectanglular 0.007 0.007 14.9 Example 4 shape

INDUSTRIAL APPLICABILITY

[0131] The present invention can provide an interlayer film for a laminated glass capable of providing a laminated glass that reduces the occurrence of optical distortion, a laminated glass including the interlayer film for a laminated glass, and a method for producing the interlayer film for laminated glass.

REFERENCE SIGNS LIST

[0132] 1 interlayer film for a laminated glass [0133] 2 roll [0134] 3 test sample [0135] 5 light source [0136] 6 laminated glass [0137] 7 screen