Embossed thermoplastic resin sheet, engraved roll, engraved roll manufacturing method, laminated glass interlayer, and laminated glass

Abstract

The present invention aims to provide an embossed thermoplastic resin sheet that is capable of enhancing deaeration during production of laminated glass and suppressing optical distortion of the resulting laminated glass to improve the visibility when used as an interlayer film for laminated glass. The present invention also relates to an engraved roll used for production of the embossed thermoplastic resin sheet, a production method of the engraved roll, an interlayer film for laminated glass including the embossed thermoplastic resin sheet, and a laminated glass. The present invention relates to an embossed thermoplastic resin sheet having a large number of recesses and a large number of projections on at least one surface, the recesses each having a groove shape with a continuous bottom and being regularly arranged side by side in parallel with one another, the thermoplastic resin sheet having not more than three defects of the projections per mm.sup.2 on the surface.

Claims

1. A method for producing an engraved roll by a blasting method, the method comprising: a step of forming an uneven pattern by spraying a blast material to a raw material roll having recessed grooves formed in parallel with one another in the circumferential direction, the blasting material being sprayed at an angle of 20? or smaller relative to a line connecting the tip of a blast gun and the axis of the raw material roll while rotating the raw material roll; and a step of removing the blast material remaining in the recessed grooves by spraying the blast material at an angle of ?20? or smaller relative to a tangential plane direction of the roll and in a direction in parallel with the recessed grooves of the roll, while rotating the roll having the uneven pattern.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a schematic view for explaining the step of forming projections and recesses in the method for producing an engraved roll of the present invention.

(2) FIG. 2 is a schematic view for explaining the step of removing the blast material in the method for producing an engraved roll of the present invention.

(3) FIG. 3 is a schematic view for explaining the groove height, the width of a bottom portion, the pitch interval and the angle of inclination of a recessed portion.

(4) FIG. 4 shows a photo (a) of a recessed groove portion of an engraved roll photographed after the step of forming projections and recesses in Example 1 and a photo (b) of a recessed groove portion of the engraved roll photographed after the step of removing the blast material in Example 1.

(5) FIG. 5 shows a photo (a) of projections and recesses of an embossed thermoplastic resin sheet obtained in Example 1 and a photo (b) of projections and recesses of an embossed thermoplastic resin sheet obtained in Comparative Example 1.

(6) FIG. 6 is an exemplary image data of an embossed thermoplastic resin sheet by a three-dimensional profilometer.

DESCRIPTION OF EMBODIMENTS

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

Example 1

(8) (1) Preparation of Raw Material Roll

(9) A mirror-finished chilled iron roll (diameter: 600 mm) was prepared, and milled in the circumferential direction for formation of a large number of recessed grooves and projected ridges on the surface, while being rotated. A raw material roll was thus prepared. In the milled pattern of projections and recesses on the raw material roll, the groove height was 250 ?m, the width of a bottom portion was 0 ?m, the pitch interval was 300 ?m, the angle of inclination was 15?, and the axis angle of a recessed groove was 85?.

(10) (2) Production of Engraved Roll

(11) The blast material used was alumina #250 (corresponding to #280 according to the JIS standard (JIS R 6001-1998)). The blast material was sprayed to the raw material roll at an angle of 0? relative to the line connecting the tip of a blast gun and the axis of the raw material roll, while the raw material roll was rotated. In this manner, an uneven pattern was formed on the surface of the raw material roll (Step of forming projections and recesses).

(12) The blast material was sprayed under the conditions of an air pressure of 2.5 kgf/cm.sup.2, a nozzle aperture of 8 mm, and a rotation speed of the raw material roll of 30 m/min, while the blast gun was moved from one end to the other end of the roll at a moving speed of 2 mm per rotation of the raw material roll.

(13) Then, the blast material was sprayed to the roll having the uneven pattern at an angle of 0? relative to the tangential plane direction of the roll and in a direction in parallel with the recessed grooves of the roll, while the roll is rotated, for removal of the blast material remaining in the recessed grooves. In this manner, an engraved roll was obtained (Step of removing blast materials).

(14) (3) Production of Embossed Thermoplastic Resin Sheet

(15) Polyvinyl alcohol having an average degree of polymerization of 1700 was acetalized with n-butylaldehyde to prepare 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 triethyleneglycol-di-2-ethylhexanoate (3GO) as a plasticizer. The mixture was sufficiently kneaded with a mixing roll to prepare a resin composition. The obtained resin composition was extruded through an extruder to give a thermoplastic resin sheet with a thickness of 760 ?m.

(16) A pair of rolls including the obtained engraved roll and a rubber roll having a JIS hardness of 70 to 90 was used as a device for transferring an uneven pattern. The obtained thermoplastic resin sheet was passed through the device for transferring an uneven pattern, whereby projections and recesses were transferred to one surface of the sheet. The transfer conditions employed here were a temperature of the thermoplastic resin sheet of 70? C., a temperature of the rolls of 140? C., a linear velocity of 10 m/min, and a linear pressure of 1 to 300 kN/m. Subsequently, the same treatment was performed to transfer projections and recesses to the other surface of the sheet under the same conditions.

Examples 2 to 9

(17) Engraved rolls were produced under the same conditions for spraying the blast material and through the same step for removing the blast material as those in Example 1, except that the raw material roll used in (2) Production of engraved roll and the angle for spraying the blast material relative to the tangential plane in the step of removing the blast material were changed as shown in Tables 1 and 2. Then, embossed thermoplastic resin sheets were produced. In Examples 8 and 9, however, only the step of forming projections and recesses was performed and the step of removing the blast material was not performed.

Comparative Example 1, 2

(18) Engraved rolls were produced under the same conditions for spraying the blast material as those in Example 1, except that the raw material roll used in (2) Production of engraved roll was changed as shown in Table 2 and that the step of removing the blast material was not performed. Then embossed thermoplastic resin sheets were produced.

Example 10

(19) (Production of Embossed Multilayer Thermoplastic Resin Sheet)

(20) (1) Preparation of Resin Composition for Forming First Resin Layer (Sound Insulation Layer)

(21) Polyvinyl alcohol having an average degree of polymerization of 2400 was acetalized with n-butyraldehyde to prepare polyvinyl butyral (acetyl group content: 12 mol %, butyral group content: 66 mol %, hydroxy group content: 22 mol %). To 100 parts by mass of the polyvinyl butyral were added 60 parts by mass of triethylene glycol-di-2-ethylhexanoate (3GO) as a plasticizer. The mixture was sufficiently kneaded with a mixing roll. Thus, a resin composition for forming a first resin layer (sound insulation layer) was prepared.

(22) (2) Preparation of Resin Composition for Forming Second Resin Layer (Protective Layer)

(23) Polyvinyl alcohol having an average degree of polymerization of 1700 was acetalized with n-butyraldehyde to prepare 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-ethylhexanoate (3GO) as a plasticizer. The mixture was sufficiently kneaded with a mixing roll. Thus, a resin composition for forming a second resin layer (protective layer) was prepared.

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

(25) The resin composition for forming a first resin layer (sound insulation layer) and the resin composition for forming a second resin layer (protective layer) were co-extruded through a co-extruder to produce a multilayer thermoplastic resin sheet (thickness: 0.8 mm) in which a first resin layer (sound insulation layer) was interposed between two second resin layers (protective layers). The first resin layer had a thickness of 0.1 mm, and the second resin layers each had a thickness of 0.35 mm. Hereafter, the three layers may be called a second resin layer A, the first resin layer, and a second resin layer B in the order of lamination in the thickness direction for identification of two second resin layers.

(26) A pair of rolls including the engraved roll obtained in Example 1 and a rubber roll having a JIS hardness of 70 to 90 was used as a device for transferring an uneven pattern. The obtained multilayer thermoplastic resin sheet was passed through the device for transferring an uneven pattern, whereby projections and recesses were transferred to one surface of the sheet. The transferring conditions employed here were a temperature of the thermoplastic resin sheet of 70? C., a temperature of the rolls of 140? C., a linear velocity of 10 m/min, and a linear pressure of 1 to 300 kN/m. Subsequently, the same treatment was performed to transfer projections and recesses to the other surface of the sheet under the same conditions.

Examples 11 to 22

(27) Engraved rolls were produced under the same conditions for spraying the blast material and through the same step for removing the blast material as those in Example 10, except that the composition of polyvinyl butyral used in the first resin layer and the second resin layer, the raw material roll used in (2) Production of engraved roll, and the angle for spraying the blast material relative to the tangential plane in the step of removing the blast material were changed as shown in Tables 3 to 5. Then, embossed thermoplastic resin sheets were produced. In Examples 17 and 18, however, only the step of forming projections and recesses was performed and the step of removing the blast material was not performed.

Comparative Example 3, 4

(28) Engraved rolls were produced under the same conditions for spraying the blast material as those in Example 10, except that the raw material roll used in (2) Production of engraved roll was changed as shown in Table 4 and that the step of removing the blast material was not performed. Then, embossed thermoplastic resin sheets were produced.

(29) (Evaluation)

(30) The engraved rolls and the embossed thermoplastic resin sheets obtained in the examples and the comparative examples were evaluated by the following methods.

(31) Tables 1 to 5 show the results.

(32) (1) Measurement of the Number of Blast Material Pieces Present in Recessed Grooves of Engraved Roll

(33) The recessed groove portion of each engraved roll were photographed at a 200? magnification with a microscope (Dino-Lite Pro2, model: DILITE80 produced by AnMo Electronics corporation). The number of remaining blast material pieces with a maximum length of 10 ?m or larger present in a range of 1290 ?m?1024 ?m in the obtained photograph was counted. The number of remaining blast material pieces was similarly counted at 10 points on each of the positions at ?, 2/4, and ? of the obtained engraved roll from both ends in the width direction in such a manner that each field of view does not overlap with each other. The arithmetic mean of the obtained values was taken as the average number of the blast material pieces in the recessed grooves of the engraved roll.

(34) The number of blast material pieces was counted after the step of forming projections and recesses and after the step of removing blast materials. In Examples 8, 9, 17, and 18 and Comparative Examples 1 to 4, counting of the number of the blast material pieces after the step of removing the blast material was omitted because the step of removing blast material pieces was not performed and the number of the blast material pieces was not changed.

(35) FIG. 4(a) is a photograph of a recessed groove portion of the engraved roll after the step of forming projections and recesses in Example 1. FIG. 4(b) is a photograph of the recessed groove portion of the engraved roll after the step of removing the blast material in Example 1.

(36) (2) Evaluation of Pattern of Projections and Recesses on Embossed Thermoplastic Resin Sheet

(37) The surface roughness of the embossed thermoplastic resin sheet in a field of view of 5 mm?5 mm was measured with a three-dimensional profilometer (KS-1100 produced by KEYENCE CORPORATION, head: model LT-9510VM) for evaluation of the projections and recesses on the embossed thermoplastic resin sheet. In the obtained image data, Ra of the apex portions of the projections and height difference r were measured in a direction in parallel with the projections. The number of portions where r is higher than Ra by 30 ?m or more was counted as defects. Here, Ra refers to the arithmetic mean roughness Ra specified in JIS B-0601 (1994). Ra is a value calculated using KS-Analyzer Ver. 2.00, analysis software included with the three-dimensional profilometer, in the line roughness measurement mode based on the roughness profile data obtained by drawing a measuring line from one end to the other end of the field of view in a direction in parallel with the direction in which the apex portions of the projections are continuous. The height difference r is determined as follows. The obtained roughness profile is divided at 500-?m intervals into plural sections starting from the upper side or the left side of the field of view with which an apex portion of a projection is in contact. The difference between the maximum height and the minimum height in each section is taken as the height difference r. The height difference of all the projections present in the field of view is determined by the same method. The correction conditions employed for obtaining the roughness profile data are cut-off value of 2.5 mm, no height smoothing, no tilt correction, and automatic range setting. The measurement conditions other than the field of view are as follows: stage feed condition: continuous; scan direction: bi-directional scanning; leading axis: X-axis; stage travel rate: 250.0 ?m/s; axis feed rate: 10000.0 ?m/s; measuring pitch of X axis: 2.0 ?m; and measuring pitch of Y axis: 2.0 ?m. The arithmetic mean is obtained by counting the number of defects at four points at each of the positions of ?, 2/4, and ? of a roll of the resulting thermoplastic resin sheet from both ends in the width direction. The obtained value was taken as the number of defects of the projections.

(38) FIG. 5(a) is a photograph of projections and recesses of the embossed thermoplastic resin sheet obtained in Example 1. FIG. 5(b) is a photograph of projections and recesses of the embossed thermoplastic resin sheet obtained in Comparative Example 1.

(39) FIG. 6 shows exemplary image data of embossed thermoplastic resin sheet created by the three-dimensional profilometer.

(40) The roughness (Rz) of the recesses in the shape of engraved lines on one surface of the obtained embossed thermoplastic resin sheet was measured by a method in conformity with JIS B-0601(1994). The measurement may be performed in a direction perpendicular to the engraved lines at a cut-off value of 2.5 mm, a standard length of 2.5 mm, a measurement length of 12.5 mm, a tip radius of a stylus of 2 ?m, a tip angle of 60?, and a measurement rate of 0.5 mm/s. The roughness on the other surface on the opposite side of the above surface was the same, and therefore, Tables 1 to 5 only show the values of Rz on one surface.

(41) (3) Evaluation of Deaeration Properties

(42) The obtained embossed thermoplastic resin sheet was used as an interlayer film for laminated glass, and a laminated glass was produced by preliminary pressure bonding through deaeration under reduced pressure, followed by final pressure bonding, as described below.

(43) (Preliminary Pressure Bonding)

(44) The interlayer film for laminated glass was sandwiched between two clear glass sheets (30 cm in length?30 cm in width?2.5 mm in thickness), and a portion protruding therefrom was cut, thereby preparing a laminate. The obtained laminate was placed in 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 laminate reached 70? C. Thereafter, the pressure was returned to atmospheric pressure, whereby completing the preliminary pressure bonding. The preliminary pressure bonding was performed under three different conditions of a deaeration start temperature of 40? C., 50? C., and 60? C.

(45) (Final Pressure Bonding)

(46) The laminate after the preliminary pressure bonding 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.

(47) (Bake Test of Laminated Glass)

(48) The obtained laminated glass was heated in an oven at 140? C. for two hours. The resulting laminated glass was taken out from the oven and cooled for three hours. The appearance of the laminated glass was visually observed to check the number of the laminated glass sheets in which foaming (bubbles) occurred for evaluation of deaeration properties. Twenty sheets were tested for each laminated glass.

(49) The case where the number of glass sheets in which foaming occurred was 5 or less among 20 sheets under any of the deaeration start temperature conditions was rated ? (good). The case where the number of glass sheets in which foaming occurred was more than 5 among 20 sheets under any one of the deaeration start temperature conditions was rated ? (poor).

(50) (4) Evaluation of Optical Distortion (Visual Evaluation)

(51) A laminated glass was produced in the same manner as in the case of the evaluation of deaeration properties.

(52) A fluorescent lamp (produced by Panasonic Corporation, FL32S.D) was set at a point of 7 m distant from an observer. The laminated glass was set at a point of 40 cm distant from the observer on the line connecting the fluorescent lamp and the observer in such a manner that the laminated glass was inclined 45? relative to the horizontal plane. The case where the fluorescent lamp seen through the laminated glass was distorted was rated ? (poor), and the case where the fluorescent lamp seen through the laminated glass was not distorted was rated ? (good). The optical distortion was evaluated at 25? C.

(53) (5) Evaluation of Optical Distortion Value

(54) A laminated glass was produced in the same manner as in the case of evaluation of deaeration properties.

(55) The optical distortion value was measured with an optical distortion inspecting device disclosed in JP-A H07-306152. The optical distortion inspecting 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 section for generating a gradation image by capturing the projection plane; and an image processing section for determining the presence or absence of distortion based on the variation in the gradation level of the gradation image generated by the image inputting section. Specifically, upon evaluation of the optical distortion by using EYE DICHO-COOL HALOGEN (15V100W) produced by Iwasaki Electric Co., Ltd. as a light source, the illuminance of the light source, the angle of a screen where an optical distortion image is to be projected, and the angle of a 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 R3211 (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 under the condition of the laminated glass temperature of 25? C. 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.

(56) TABLE-US-00001 TABLE 1 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Shape of Groove 250 330 250 250 250 80 recessed height grooves of raw (?m) material roll Width of 0 15 40 40 40 5 bottom portion (?m) Pitch interval 300 200 400 400 400 220 (?m) Angle of 15 15 15 15 15 15 inclination (?) Roll diameter 600 600 600 600 600 600 (mm) Axis angle 85 85 85 85 85 85 of recessed groove (?) Step of Spraying 0 0 0 15 10 10 removing angle blast material relative to tangential plane of roll (?) Number of After step 80 100 or more 60 60 60 100 or more blast material of forming pieces in projections recessed grooves and recesses of engraved After step 0.30 0.71 0.20 2.75 1.45 2.83 roll (pcs/mm.sup.2) of removing blast material Number of defective 0.04 0.08 0.02 0.25 0.15 0.77 projections or recesses on embossed thermoplastic resin sheet (pcs/mm.sup.2) Roughness of Ra (?m) 3.5 4.3 4.5 3.5 3 2.5 embossment at apex portion Roughness of Rz (?m) 38 33 35 35 34 40 embossment Evaluation of Deaeration 40 50 60 40 50 60 40 50 60 40 50 60 40 50 60 40 50 60 deaeration start properties temperature (? C.) Preliminary 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 pressure bonding temperature (? C.) Bake test 0 0 0 0 0 0 0 0 1 0 1 3 0 1 1 1 1 1 (Number of sheets with foaming/20 sheets) Evaluation ? ? ? ? ? ?

(57) TABLE-US-00002 TABLE 2 Comparative Comparative Example 7 Example 8 Example 9 Example 1 Example 2 Shape of Groove 80 200 200 250 250 recessed height grooves of raw (?m) material roll Width of 0 30 30 0 40 bottom portion (?m) Pitch interval 190 300 300 300 400 (?m) Angle of 15 30 25 15 15 inclination (?) Roll 600 600 600 600 600 diameter (mm) Axis angle 85 85 85 85 85 of recessed groove (?) Step of Spraying 0 0 0 removing angle blast material relative to tangential plane of roll (?) Number of After step 100 or more 11 24 80 60 blast material of forming pieces projections present in and recesses recessed grooves After step 2.75 of engraved of removing roll (pcs/mm.sup.2) blast material Number of defective 0.90 1.15 2.73 12.00 6.00 projections or recesses on embossed thermoplastic resin sheet (pcs/mm.sup.2) Roughness of Ra (?m) 2.5 4.5 3.5 6 5.8 embossment at apex portion Roughness of Rz(?m) 34 38 35 35 33 embossment Evaluation of Deaeration 40 50 60 40 50 60 40 50 60 40 50 60 40 50 60 deaeration start properties temperature (? C.) Preliminary 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 pressure bonding temperature (? C.) Bake test 0 1 2 1 1 3 2 2 4 2 5 8 2 3 6 (Number of sheets with foaming/20 sheets) Evaluation ? ? ? x x

(58) TABLE-US-00003 TABLE 3 Example 10 Example 11 Example 12 Example 13 Example 14 Example 15 Formu- Composi- Bu degree 69 69 69 69 69 69 lation tion of (mol %) protective OH degree 30 30 30 30 30 30 layer (mol %) Ac degree 1 1 1 1 1 1 (mol %) Plasticizer 40 40 40 40 40 40 content (phr) Composi- Bu degree 66 66 66 66 66 66 tion of (mol %) sound- OH degree 22 22 22 22 22 22 insulating (mol %) layer Ac degree 12 12 12 12 12 12 (mol %) Plasticizer 60 60 60 60 60 60 content (phr) Thickness Second resin 350 350 350 350 350 350 layer A (?m) First resin 100 100 100 100 100 100 layer (?m) Second resin 350 350 350 350 350 350 layer B (?m) Shape of Groove 250 330 250 250 250 80 recessed height grooves of raw (?m) material roll Width of 0 15 40 40 40 5 bottom portion (?m) Pitch interval 300 200 400 400 400 220 (?m) Angle of 15 15 15 15 15 15 inclination (?) Roll 600 600 600 600 600 600 diameter (mm) Axis angle 85 85 85 85 85 85 of recessed groove (?) Step of Spraying 0 0 0 15 10 10 removing angle blast material relative to tangential plane of roll (?) Number of After step 80 100 or more 60 60 60 100 or more blast material of forming pieces projections present in and recesses recessed grooves After step 0.30 0.71 0.20 2.75 1.45 2.83 on engraved of removing roll (pcs/mm.sup.2) blast material Number of defective 0.04 0.09 0.02 0.24 0.13 0.67 projections or recesses on embossed thermoplastic resin sheet (pcs/mm.sup.2) Roughness of Ra (?m) 2.3 2.5 3.5 2.5 2.4 3.5 embossment at apex portion Roughness of Rz(?m) 33 35 34 35 33 40 embossment Evaluation of Deaeration 40 50 60 40 50 60 40 50 60 40 50 60 40 50 60 40 50 60 deaeration start properties temperature (? C.) Preliminary 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 pressure bonding temperature (? C.) Bake test 0 0 0 0 0 0 0 0 1 1 1 2 1 1 1 1 1 2 (Number of sheets with foaming/20 sheets) Evaluation ? ? ? ? ? ? Visual 25? C. ? ? ? ? ? ? evaluation of optical distortion Optical 25? C. 1.40 1.40 1.40 1.41 1.45 1.48 distortion value

(59) TABLE-US-00004 TABLE 4 Comparative Comparative Example 16 Example 17 Example 18 Example 3 Example 4 Formu- Composi- Bu degree 69 69 69 69 69 lation tion of (mol %) protective OH degree 30 30 30 30 30 layer (mol %) Ac degree 1 1 1 1 1 (mol %) Plasticizer 40 40 40 40 40 content (phr) Composi- Bu degree 66 66 66 66 66 tion of (mol %) sound OH degree 22 22 22 22 22 insulation (mol %) layer Ac degree 12 12 12 12 12 (mol %) Plasticizer 60 60 60 60 60 content (phr) Thickness Second resin 350 350 350 350 350 layer A (?m) First resin 100 100 100 100 100 layer (?m) Second resin 350 350 350 350 350 layer B (?m) Shape of Groove 80 200 200 250 250 recessed height grooves of raw (?m) material roll Width of 0 30 30 0 40 bottom portion (?m) Pitch interval 190 300 300 300 400 (?m) Angle of 15 30 25 15 15 inclination (?) Roll 600 600 600 600 600 diameter (mm) Axis angle 85 85 85 85 85 of recessed groove (?) Step of Spraying 0 0 0 removing angle blast relative to material tangential plane of roll (?) Number of After step 100 or more 11 24 80 60 blast material of forming pieces projections present in and recesses recessed grooves After step 2.75 of engraved of removing roll (pcs/mm.sup.2) blast materials Number of defective 0.97 1.35 2.70 11.50 6.50 projections or recesses on embossed thermoplastic resin sheet (pcs/mm.sup.2) Roughness of Ra (?m) 2.5 5.5 6.3 5.5 6.3 embossment at apex portion Roughness of Rz(?m) 45 40 35 33 33 embossment Evaluation of Deaeration 40 50 60 40 50 60 40 50 60 40 50 60 40 50 60 deaeration start properties temperature (? C.) Preliminary 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 pressure bonding temperature (? C.) Bake test 1 1 3 1 2 4 1 3 4 3 5 13 3 5 10 (Number of sheets with foaming/20 sheets) Evaluation ? ? ? x x Visual 25? C. ? ? ? x x evaluation of optical distortion Optical 25? C. 1.49 1.56 1.79 3.50 2.21 distortion value

(60) TABLE-US-00005 TABLE 5 Example 19 Example 20 Example 21 Example 22 Formu- Composi- Bu degree 69 68.5 69 70 lation tion of (mol %) protective OH degree 30 31 30.7 29 layer (mol %) Ac degree 1 0.5 0.3 1 (mol %) Plasticizer 36 36 37.5 39 content (phr) Composi- Bu degree 66 67.5 71 77.7 tion of (mol %) sound OH degree 24.5 24.5 23 20.8 insulation (mol %) layer Ac degree 10.5 8 6 1.5 (mol %) Plasticizer 75 75 76 77 content (phr) Thickness Second resin 350 350 350 350 layer A (?m) First resin 100 100 100 100 layer (?m) Second resin 350 350 350 350 layer B (?m) Shape of Groove 250 250 250 250 recessed height grooves of raw (?m) material roll Width of 0 0 0 0 bottom portion (?m) Pitch interval 300 300 300 300 (?m) Angle of 15 15 15 15 inclination (?) Roll 600 600 600 600 diameter (mm) Axis angle 85 85 85 85 of recessed groove (?) Step of Spraying 0 0 0 0 removing angle blast relative to material tangential plane of roll (?) Number of After step 80 80 80 80 blast material of forming pieces present in projections recessed grooves and recesses on engraved After step 0.30 0.30 0.30 0.30 roll (pcs/mm.sup.2) of removing blast materials Number of defective 0.03 0.01 0.03 0.02 projections or recesses on embossed thermoplastic resin sheet (pcs/mm.sup.2) Roughness of Ra (?m) 3.2 3.3 2.5 2.6 embossment at apex portion Roughness of Rz(?m) 37 38 40 40 embossment Evaluation of Deaeration 40 50 60 40 50 60 40 50 60 40 50 60 deaeration start properties temperature (? C.) Preliminary 70 70 70 70 70 70 70 70 70 70 70 70 pressure bonding temperature (? C.) Bake test 0 0 0 0 0 0 0 0 0 0 0 0 (Number of sheets with foaming/20 sheets) Evaluation ? ? ? ? Visual 25? C. ? ? ? ? evaluation of optical distortion Optical 25? C. 1.36 1.39 1.41 1.38 distortion value

INDUSTRIAL APPLICABILITY

(61) The present invention can provide an embossed thermoplastic resin sheet that is capable of enhancing deaeration during production of laminated glass and suppressing optical distortion of the resulting laminated glass to improve the visibility when used as an interlayer film for laminated glass, an engraved roll used for production of the embossed thermoplastic resin sheet, a production method of the engraved roll, an interlayer film for laminated glass including the embossed thermoplastic resin sheet, and a laminated glass.

REFERENCE SIGNS LIST

(62) 1. Roll 2. Blast gun