Interlayer film for laminated glass, and laminated glass
10350858 ยท 2019-07-16
Assignee
Inventors
Cpc classification
B32B3/30
PERFORMING OPERATIONS; TRANSPORTING
International classification
Abstract
The present invention aims to provide an interlayer film for laminated glass having small optical distortion while having a multilayer structure of two or more layers, and a laminated glass including the interlayer film for laminated glass. The present invention relates to an interlayer film for laminated glass including at least two resin layers laminated together, the interlayer film having a large number of minute recesses and a large number of minute projections on at least one surface, the at least two resin layers including a first surface layer and a second surface layer and each containing a thermoplastic resin and a plasticizer, wherein, provided that the interlayer film is allowed to stand at 23? C. and a humidity of 30% RH for three hours, and cut with a microtome at 23? C. and a humidity of 30% RH in the horizontal direction of the interlayer film at a portion of 80 to 90 ?m distant on the first surface layer side from the interface between the first surface layer and a resin layer contacting the interior side of the first surface layer and then at a portion of 50 ?m distant from the cut face on the second surface layer side to prepare a resin film 1 having a thickness of 50 ?m, the resin film 1 after standing at a temperature of 23? C. and a humidity of 30% RH for three hours has a surface roughness (Rz) measured by a method in conformity with JIS B-0601 (1994) of less than 2.5 ?m.
Claims
1. An interlayer film for a laminated glass comprising a first surface layer, a second surface layer, and an intermediate layer therebetween, wherein the intermediate layer comprises at least two resin layers, wherein the intermediate layer, the first surface layer, and the second surface layer are laminated together, wherein each of the at least two resin layers, the first surface layer, and the second surface layer contains a thermoplastic resin and a plasticizer, and wherein the interlayer film has recesses and projections on at least one surface, wherein, provided that the interlayer film is allowed to stand at 23? C. and a humidity of 30% RH for three hours, and cut with a microtome at 23? C. and a humidity of 30% RH in the horizontal direction of the interlayer film at a portion of 80 to 90 ?m distant on a first surface layer side from the interface between the first surface layer and a resin layer contacting the interior side of the first surface layer and then at portion of 50 ?m distant from the cut face on a second surface layer side to prepare a resin film 1 having a thickness of 50 ?m, the resin film 1 after standing at a temperature of 23? C. and a humidity of 30% RH for three hours has a surface roughness (Rz) measured by a method in conformity with JIS B-0601 (1994) of less than 2.5 ?m, wherein the first surface layer has a thickness of 200 ?m or more, wherein the second surface layer has a thickness of 200 ?m or more, wherein the interlayer film has a creep elongation rate at 80? C. of 80% or lower, and wherein the interlayer has an optical distortion of less than 1.8 when an extension rate is 1 time the original length and a ratio of an optical distortion when an extension rate is 1.2 times the original length to the optical distortion when an extension rate is 1 time the original length is 1.2 or less.
2. The interlayer film for laminated glass according to claim 1, wherein, provided that the interlayer film is allowed to stand at 23? C. and a humidity of 30% RH for three hours, and cut at a portion of 80 to 90 ?m distant on the second surface layer side from the interface between the second surface layer and a resin layer contacting the interior side of the second surface layer and then at a portion of 50 ?m distant from the cut face on the first surface layer side to prepare a resin film 2 having a thickness of 50 ?m, the resin film 2 after standing at a temperature of 23? C. and a humidity of 30% RH for three hours has a surface roughness (Rz) measured by a method in conformity with JIS B-0601 (1994) of less than 2.5 ?m.
3. The interlayer film for laminated glass according to claim 1, wherein, provided that the interlayer film is allowed to stand at 23? C. and a humidity of 30% RH for three hours, and cut with a microtome at 23? C. and a humidity of 30% RH in the horizontal direction of the interlayer film at a portion of 80 to 90 ?m distant on the first surface layer side from the interface between the first surface layer and a resin layer contacting the interior side of the first surface layer and then at a portion of 50 ?m distant from the cut face on the second surface layer side to prepare a resin film 1 having a thickness of 50 ?m, the resin film 1 after standing at a temperature of 23? C. and a humidity of 30% RH for three hours has a surface roughness (Rz) measured by a method in conformity with JIS B-0601 (1994) of less than 1.9 ?m.
4. The interlayer film for laminated glass according to claim 2, wherein, provided that the interlayer film is allowed to stand at 23? C. and a humidity of 30% RH for three hours, and cut at a portion of 80 to 90 ?m distant on the second surface layer side from the interface between the second surface layer and a resin layer contacting the interior side of the second surface layer and then at a portion of 50 ?m distant from the cut face on the first surface layer side to prepare a resin film 2 having a thickness of 50 ?m, the resin film 2 after standing at a temperature of 23? C. and a humidity of 30% RH for three hours has a surface roughness (Rz) measured by a method in conformity with JIS B-0601 (1994) of less than 1.9 ?m.
5. The interlayer film for laminated glass according to claim 1, which has a creep elastic modulus at 80? C. of 0.030 MPa or higher.
6. A laminated glass comprising a pair of glass sheets and the interlayer film for laminated glass according to claim 1 interposed between the pair of glass sheets.
7. An interlayer film for a laminated glass comprising a first surface layer, a second surface layer, and an intermediate layer therebetween, wherein the intermediate layer comprises at least two resin layers, wherein the intermediate layer, the first surface layer, and the second surface layer are laminated together, wherein each of the at least two resin layers, the first surface layer, and the second surface layer contains a thermoplastic resin and a plasticizer, and wherein the interlayer film has recesses and projections on at least one surface, wherein, provided that the interlayer film is allowed to stand at 23? C. and a humidity of 30% RH for three hours, and cut with a microtome at 23? C. and a humidity of 30% RH in the horizontal direction of the interlayer film at a portion of 80 to 90 ?m distant on a first surface layer side from the interface between the first surface layer and a resin layer contacting the interior side of the first surface layer and then at portion of 50 ?m distant from the cut face on a second surface layer side to prepare a resin film 1 having a thickness of 50 ?m, the resin film 1 after standing at a temperature of 23? C. and a humidity of 30% RH for three hours has a surface roughness (Rz) measured by a method in conformity with JIS B-0601 (1994) of less than 2.5 ?m, wherein the first surface layer has a thickness of 200 ?m or more, wherein the second surface layer has a thickness of 200 ?m or more, wherein the interlayer film has a creep elongation rate at 80? C. of 80% or lower, and wherein the interlayer has an optical distortion of 3 or less when an extension rate is 1 time the original length and an optical distortion of 5 or less when an extension rate is 1.2 times the original length.
8. The interlayer film for laminated glass according to claim 7, wherein, provided that the interlayer film is allowed to stand at 23? C. and a humidity of 30% RH for three hours, and cut at a portion of 80 to 90 ?m distant on the second surface layer side from the interface between the second surface layer and a resin layer contacting the interior side of the second surface layer and then at a portion of 50 ?m distant from the cut face on the first surface layer side to prepare a resin film 2 having a thickness of 50 ?m, the resin film 2 after standing at a temperature of 23? C. and a humidity of 30% RH for three hours has a surface roughness (Rz) measured by a method in conformity with JIS B-0601 (1994) of less than 2.5 ?m.
9. The interlayer film for laminated glass according to claim 7, wherein, provided that the interlayer film is allowed to stand at 23? C. and a humidity of 30% RH for three hours, and cut with a microtome at 23? C. and a humidity of 30% RH in the horizontal direction of the interlayer film at a portion of 80 to 90 ?m distant on the first surface layer side from the interface between the first surface layer and a resin layer contacting the interior side of the first surface layer and then at a portion of 50 ?m distant from the cut face on the second surface layer side to prepare a resin film 1 having a thickness of 50 ?m, the resin film 1 after standing at a temperature of 23? C. and a humidity of 30% RH for three hours has a surface roughness (Rz) measured by a method in conformity with JIS B-0601 (1994) of less than 1.9 ?m.
10. The interlayer film for laminated glass according to claim 8, wherein, provided that the interlayer film is allowed to stand at 23? C. and a humidity of 30% RH for three hours, and cut at a portion of 80 to 90 ?m distant on the second surface layer side from the interface between the second surface layer and a resin layer contacting the interior side of the second surface layer and then at a portion of 50 ?m distant from the cut face on the first surface layer side to prepare a resin film 2 having a thickness of 50 ?m, the resin film 2 after standing at a temperature of 23? C. and a humidity of 30% RH for three hours has a surface roughness (Rz) measured by a method in conformity with JIS B-0601 (1994) of less than 1.9 ?m.
11. The interlayer film for laminated glass according to claim 7, which has a creep elastic modulus at 80? C. of 0.030 MPa or higher.
12. A laminated glass comprising a pair of glass sheets and the interlayer film for laminated glass according to claim 7 interposed between the pair of glass sheets.
Description
BRIEF DESCRIPTION OF DRAWINGS
(1)
(2)
(3)
(4)
DESCRIPTION OF EMBODIMENTS
(5) Embodiments of the present invention are specifically described with reference to, but not limited to, examples.
Example 1
(6) (1) Preparation of Resin Composition for Sound Insulation Layer
(7) Polyvinyl alcohol having an average degree of polymerization of 2300 was acetalized with n-butyraldehyde to give polyvinyl butyral (acetyl group content: 12.5 mol %, butyral group content: 64.5 mol %, hydroxy group content: 23.0 mol %). An amount of 100 parts by mass of the polyvinyl butyral was blended with 60 parts by mass of triethylene glycol-di-2-ethylhexanoate (3GO) as a plasticizer, and sufficiently kneaded with a mixing roll to give a resin composition for sound insulation layer.
(8) (2) Synthesis of Resin for Protective Layer
(9) A reaction container equipped with a stirrer was charged with 2700 mL of ion-exchanged water and 300 g of polyvinyl alcohol (average degree of polymerization: 1700, saponification degree: 99 mol %), and the mixture was molten by heat with stirring to give a solution. The solution was blended with 60% by weight nitric acid, as a catalyst, such that the nitric acid concentration reached 0.4% by weight. The temperature of the mixture was adjusted to 15? C., and then the mixture was blended with 23 g of n-butyraldehyde with stirring. Then, the resulting solution was blended with 140 g of n-butyraldehyde, so that polyvinyl butyral in the shape of white particles was precipitated. After 15 minutes from the precipitation of the polyvinyl butyral, 60% by weight nitric acid was added such that the nitric acid concentration reached 1.6% by weight. The resulting mixture was heated to 65? C. and aged for two hours at 65? C. Next, after cooling and neutralization of the solution, the polyvinyl butyral was washed with water and dried. Polyvinyl butyral was thus prepared.
(10) (3) Preparation of Resin Composition for Protective Layer
(11) An amount of 100 parts by mass of the polyvinyl butyral obtained as a final product of the (2) Synthesis of resin for protective layer was blended with 40 parts by mass of triethylene glycol-di-2-ethylhexanoate (3GO) as a plasticizer, and kneaded well with a mixing roll to give a resin composition for protective layer.
(12) (4) Production of Interlayer Film for Laminated Glass
(13) (4-1) Production of Laminate
(14) The obtained resin composition for sound insulation layer and the resin composition for protective layer were coextruded from a coextruder to give a laminate having a triple layer structure in which a first surface layer (protective layer) made of the resin composition for protective layer with a thickness of 340 ?m, an intermediate layer (sound insulation layer) made of the resin composition for sound insulation layer with a thickness of 100 ?m, and a second surface layer (protective layer) made of the resin composition for protective layer with a thickness of 370 ?m were laminated in the stated order.
(15) (4-2) Formation of Recesses and Projections
(16) The resulting laminate was passed through a pair of embossing rolls, a device for transferring a pattern of projections and recesses, on which a large number of minute recesses and a large number of minute projections were formed, thereby preparing a laminate on which a large number of minute recesses and a large number of minute projections were formed.
(17) A pair of embossing 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 laminate on which a large number of minute recesses and a large number of minute projections were formed was passed through the embossing rolls, whereby projections and recesses having a surface roughness (Rz) of 31 ?m in which recesses having a groove shape with a continuous bottom (shape of an engraved line) were formed in parallel with one another at equal intervals were imparted to the surface of the first surface layer and the surface of the second surface layer of the laminate. An interlayer film for laminated glass was thus prepared. The surface roughness Rz was measured by a method in conformity with JIS B-0601 (1994). The transferring for formation of recesses having a groove shape (shape of an engraved line) was performed under the conditions of a temperature of the laminate of 95? C., a roll temperature of 130? C., and a pressure of 500 kPa.
(18) (5) Production of Laminated Glass
(19) The obtained interlayer film for laminated glass was used for production of two types of laminated glasses having different extension rates of the interlayer film for laminated glass of 1 and 1.2 times the original length.
(20) First, a laminated glass in which the extension rate of the interlayer film for laminated glass was 1 time was produced as follows.
(21) The interlayer film for laminated glass obtained in (4) production of 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) in conformity with JIS R 3202 (1996), and a portion protruding therefrom was cut, whereby preparing a laminated glass component. The obtained laminated glass component 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 component reached 70? C. Thereafter, the pressure was returned to atmospheric pressure, whereby completing the preliminary pressure-bonding. The preliminarily pressure-bonded laminated glass component was placed in an autoclave, and held at a temperature of 140? C. and a pressure of 1300 kPa for ten 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.
(22) Next, a laminated glass in which the extension rate of the interlayer film for laminated glass was 1.2 times was prepared as follows.
(23) The interlayer film for laminated glass obtained in (4) Production of interlayer film for laminated glass was heated in a gear oven until the temperature of the film surface reached 120? C. The interlayer film for laminated glass was then extended at a rate of 5 to 15 cm/s until the length thereof became longer than the length before heating by 1.2 times. The interlayer film for laminated glass was immobilized with a jig so that the extension by 1.2 times was maintained, and cooled with water at 25? C. The cooled film was allowed to stand in an immobilized state at a temperature of 25? C. and a humidity of 30% RH for 12 hours to be dried. The dried 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) in conformity with JIS R 3202 (1996), and a portion protruding from the laminate was cut, whereby preparing a laminated glass component. The obtained laminated glass component 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 component reached 70? C. Thereafter, the pressure was returned to atmospheric pressure, whereby completing the preliminary pressure-bonding. The preliminarily pressure-bonded laminated glass component 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.
Example 2
(24) An interlayer film for laminated glass and laminated glasses were prepared in the same manner as in Example 1, except that the temperature of the laminate and the coarseness of embossing pattern during formation of recesses having a groove shape (shape of an engraved line) in (4-2) Formation of recesses and projections were changed as shown in Table 1.
Example 3
(25) Polyvinyl butyral was prepared in the same manner as in Example 1, except that the aging at 65? C. for two hours was changed to the aging at 65? C. for two hours and 15 minutes in (2) Synthesis of resin for protective layer. An interlayer film for laminated glass and laminated glasses were prepared in the same manner as in Example 1, except that the resin composition for protective layer was prepared from the obtained polyvinyl butyral in (3) Preparation of resin composition for protective layer and that the temperature of the laminate and the coarseness of embossing pattern during formation of recesses having a groove shape (shape of an engraved line) in (4-2) Formation of recesses and projections were changed as shown in Table 1.
Example 4
(26) An interlayer film for laminated glass and laminated glasses were prepared in the same manner as in Example 1, except that the temperature of the laminate and the coarseness of embossing pattern during formation of recesses having a groove shape (shape of an engraved line) in (4-2) Formation of recesses and projections were changed as shown in Table 1.
Example 5
(27) An interlayer film for laminated glass and laminated glasses were prepared in the same manner as in Example 1, except that the coarseness of the embossing pattern for forming a large number of minute recesses and a large number of minute projections, and the temperature of the laminate and the coarseness of embossing pattern during formation of recesses having a groove shape (shape of an engraved line) in (4-2) Formation of recesses and projections were changed as shown in Table 1.
Example 6
(28) A laminate on which a large number of minute recesses and a large number of minute projections were formed was prepared in the same manner as in Example 1, except that the coarseness of the embossing pattern for forming a large number of minute recesses and a large number of minute projections in (4-2) Formation of recesses and projections was changed as shown in Table 1. The obtained laminate on which a large number of minute recesses and a large number of minute projections were formed was used as an interlayer film for laminated glass on which no recesses having a groove shape (shape of an engraved line) were formed. Using the obtained interlayer film for laminated glass, laminated glasses were prepared in the same manner as in Example 1.
Example 7
(29) A laminate was prepared in the same manner as in Example 1, except that the thickness of each resin layer in (4-1) Production of laminate was changed as shown in Table 1. Using the obtained laminate, a laminate on which a large number of minute recesses and a large number of minute projections were formed was prepared in the same manner as in Example 1, except that the coarseness of the embossing pattern for forming a large number of minute recesses and a large number of minute projections was changed as shown in Table 1. The obtained laminate on which a large number of minute recesses and a large number of minute projections were formed was used as an interlayer film for laminated glass on which no recesses having a groove shape (shape of an engraved line) were formed. Using the obtained interlayer film for laminated glass, a laminated glass was prepared in the same manner as in Example 1.
Example 8
(30) The procedure of (1) Preparation of resin composition for sound insulation layer in Example 1 was changed as follows.
(31) (1) Preparation of Resin Composition for Sound Insulation Layer
(32) Polyvinyl alcohol having an average degree of polymerization of 2300 was acetalized with n-butyraldehyde to give polyvinyl butyral (acetyl group content: 0.5 mol %, butyral group content: 81.1 mol %, hydroxy group content: 18.5 mol %). An amount of 100 parts by mass of the polyvinyl butyral was blended with 60 parts by mass of triethylene glycol-di-2-ethylhexanoate (3GO) as a plasticizer, and sufficiently kneaded with a mixing roll to give a resin composition for sound insulation layer.
(33) The procedure of (2) Synthesis of resin for protective layer in Example 1 was changed as follows.
(34) (2) Synthesis of Resin for Protective Layer
(35) A reaction container equipped with a stirrer was charged with 2700 mL of ion-exchanged water and 300 g of polyvinyl alcohol having an average degree of polymerization of 1700 and a saponification degree of 99 mol %. The mixture was molten by heating with stirring to give a solution. Next, the solution was blended with 60% by weight nitric acid as a catalyst such that the nitric acid concentration reached 0.4% by weight. The temperature of the mixture was adjusted to 15? C., and then the mixture was blended with 23 g of n-butyraldehyde with stirring. Then, the resulting solution was blended with 140 g of n-butyraldehyde and 6 mg of glutaraldehyde, so that polyvinyl butyral in the shape of white particles was precipitated. After 15 minutes from the precipitation of the polyvinyl butyral, 60% by weight nitric acid was added such that the nitric acid concentration reached 1.6% by weight. The resulting mixture was heated to 64? C. and aged for two hours at 64? C. Next, after cooling and neutralization of the solution, the polyvinyl butyral was washed with water and dried. Polyvinyl butyral was thus prepared.
(36) The procedure of (3) Preparation of resin composition for protective layer in Example 1 was changed as follows.
(37) (3) Preparation of Resin Composition for Protective Layer
(38) An amount of 100 parts by mass of the polyvinyl butyral obtained as a final product in (2) Synthesis of resin for protective layer was blended with 40 parts by mass of triethylene glycol-di-2-ethylhexanoate (3GO) as a plasticizer, and the mixture was sufficiently kneaded with a mixing roll to give a resin composition for protective layer.
(39) The procedure of (4-1) Production of laminate in Example 1 was changed as follows.
(40) (4-1) Production of Laminate
(41) The resin composition for sound insulation layer and the resin composition for protective layer obtained in (1) Preparation of resin composition for sound insulation layer and (3) Preparation of resin composition for protective layer, respectively, were coextruded from a coextruder to give a laminate having a triple layer structure in which a first surface layer (protective layer) made of the resin composition for protective layer with a thickness of 345 ?m, an intermediate layer (sound insulation layer) made of the resin composition for sound insulation layer with a thickness of 100 ?m, and a second surface layer (protective layer) made of the resin composition for protective layer with a thickness of 350 ?m were laminated in the stated order. Co-extrusion was performed under the following conditions so that the melt fracture was controlled, and a laminate on which a large number of minute recesses and a large number of minute projections were formed was produced. Specifically, the die width was set to 400 mm, the extrusion amount was set to 70 kg/hr.Math.m, the die lip gap was set to 0.7 mm, and the surface temperature of the film right after coming out of the die was set to 190? C.
(42) Then, an interlayer film for laminated glass and laminated glasses were produced in the same manner as in Example 1, except that the temperature of the laminate and the coarseness of the embossing pattern during formation of recesses having a groove shape (shape of an engraved line) in (4-2) Formation of recesses and projections was changed as shown in Table 1.
Example 9
(43) The procedure of (1) Preparation of resin composition for sound insulation layer in Example 1 was changed as follows.
(44) (1) Preparation of Resin Composition for Sound Insulation Layer
(45) Polyvinyl alcohol having an average degree of polymerization of 2300 was acetalized with n-butyraldehyde to give polyvinyl butyral (acetyl group content: 7.6 mol %, butyral group content: 68.1 mol %, hydroxy group content: 24.3 mol %). An amount of 100 parts by mass of the polyvinyl butyral was blended with 60 parts by mass of triethylene glycol-di-2-ethylhexanoate (3GO) as a plasticizer, and sufficiently kneaded with a mixing roll to give a resin composition for sound insulation layer.
(46) The procedure of (4-1) Production of laminate in Example 1 was changed as follows.
(47) (4-1) Production of Laminate
(48) The resin composition for sound insulation layer and the resin composition for protective layer obtained in (1) Preparation of resin composition for sound insulation layer and (3) Preparation of resin composition for protective layer, respectively, were coextruded from a coextruder to give a laminate having a triple layer structure in which a first surface layer (protective layer) made of the resin composition for protective layer with a thickness of 337 ?m, an intermediate layer (sound insulation layer) made of the resin composition for sound insulation layer with a thickness of 107 ?m, and a second surface layer (protective layer) made of the resin composition for protective layer with a thickness of 382 ?m were laminated in the stated order. The coextrusion was performed under the following conditions so that the melt fracture was controlled, and a laminate on which a large number of minute recesses and a large number of minute projections were formed was produced. Specifically, the die width was set to 400 mm, the extrusion amount was set to 70 kg/hr.Math.m, the die lip gap was set to 0.7 mm, and the surface temperature of the film right after coming out of the die was set to 190? C.
(49) Then, an interlayer film for laminated glass and laminated glasses were produced in the same manner as in Example 1, except that the temperature of the laminate and the coarseness of the embossing pattern for forming recesses having a groove shape (shape of an engraved line) was changed as shown in Table 1 in (4-2) Formation of recesses and projections.
Example 10
(50) The procedure of (1) Preparation of resin composition for sound insulation layer in Example 1 was changed as follows.
(51) (1) Preparation of Resin Composition for Sound Insulation Layer
(52) Polyvinyl alcohol having an average degree of polymerization of 2300 was acetalized with n-butyraldehyde to give polyvinyl butyral (acetyl group content: 7.6 mol %, butyral group content: 68.1 mol %, hydroxy group content: 24.3 mol %). An amount of 100 parts by mass of the polyvinyl butyral was blended with 60 parts by mass of triethylene glycol-di-2-ethylhexanoate (3GO) as a plasticizer, and sufficiently kneaded with a mixing roll to give a resin composition for sound insulation layer.
(53) The procedure of (4-1) Production of laminate in Example 1 was changed as follows.
(54) (4-1) Production of Laminate
(55) The resin composition for sound insulation layer and the resin composition for protective layer obtained in (1) Preparation of resin composition for sound insulation layer and (3) Preparation of resin composition for protective layer, respectively, were coextruded from a coextruder to give a laminate having a triple layer structure in which a first surface layer (protective layer) made of the resin composition for protective layer with a thickness of 337 ?m, an intermediate layer (sound insulation layer) made of the resin composition for sound insulation layer with a thickness of 107 ?m, and a second surface layer (protective layer) made of the resin composition for protective layer with a thickness of 382 ?m were laminated in the stated order. The coextrusion was performed under the following conditions so that the melt fracture was controlled, and a laminate on which a large number of minute recesses and a large number of minute projections were formed was produced. Specifically, the die width was set to 400 mm, the extrusion amount was set to 70 kg/hr.Math.m, the die lip gap was set to 0.7 mm, and the surface temperature of the film right after coming out of the die was set to 185? C.
(56) Then, an interlayer film for laminated glass and laminated glasses were produced in the same manner as in Example 1, except that the recesses having a groove shape (shape of an engraved line) were not formed in (4-2) Formation of recesses and projections.
Comparative Example 1
(57) Polyvinyl butyral was prepared in the same manner as in Example 1, except that the aging time at 65? C. for two hours was changed to the aging time at 65? C. for one hour in (2) Synthesis of resin for protective layer. An interlayer film for laminated glass and laminated glasses were produced in the same manner as in Example 1, except that the obtained polyvinyl butyral was used for preparation of a resin composition for protective layer in (3) Preparation of resin composition for protective layer, that the thickness of each resin layer in (4-1) Production of laminate was set as shown in Table 1, and that the temperature of the laminate and the coarseness of the embossing pattern during formation of recesses having a groove shape (shape of an engraved line) in (4-2) Formation of recesses and projections were set as shown in Table 1.
Comparative Example 2
(58) Polyvinyl butyral was prepared in the same manner as in Example 1, except that the aging time at 65? C. for two hours was changed to the aging time at 65? C. for 30 minutes in (2) Synthesis of resin for protective layer. An interlayer film for laminated glass and laminated glasses were produced in the same manner as in Example 1, except that the obtained polyvinyl butyral was used for preparation of a resin composition for protective layer in (3) Preparation of resin composition for protective layer, and that the temperature of the laminate and the coarseness of the embossing pattern during formation of recesses having a groove shape (shape of an engraved line) in (4-2) Formation of recesses and projections were set as shown in Table 1.
(59) (Evaluation)
(60) The interlayer films for laminated glass obtained in the examples and comparative examples were evaluated as follows. Table 1 shows the results.
(61) (1) Evaluation on Surface Roughness (Rz) of Resin Film 1 and Resin Film 2 Sampled from Interlayer Film
(62) Each obtained interlayer film for laminated glass was left to stand at 23? C. and a humidity of 30% RH for three hours and then attached to a flat acrylic sheet with an adhesive (Cemedine Co., Ltd., 3000 GOLD Liquid) in such a manner that the exterior surface of the second surface layer was in contact with the acrylic sheet. The resulting film was dried at 23? C. for 24 hours. Next, after standing at 23? C. and a humidity of 30% RH for three hours, the film was cut with a microtome (Leica, RM2265, Grade of blade Leica 819 Blade) at 23? C. and a humidity of 30% RH in the horizontal direction of the interlayer film for laminated glass, thereby preparing a plurality of resin films. The cutting direction was set in parallel with the machine direction in film formation.
(63) Here, the film was cut at a portion of 80 to 90 ?m distant on the first surface layer side from the interface between the first surface layer and the intermediate layer and then at a portion of 50 ?m distant from the cut face on the second surface layer side to give a resin film 1 having a thickness of 50 ?m.
(64) The film was attached to a flat acrylic sheet in such a manner that the exterior side of the first surface layer, not the exterior side of the second surface layer, was in contact with the acrylic sheet. Then, the film was cut similarly, that is, cut at a portion of 80 to 90 ?m distant on the second surface layer side from the interface between the second surface layer and the intermediate layer and then at a portion of 50 ?m distant from the cut face on the first surface layer side to give a resin film 2 with a thickness of 50 ?m.
(65) The resin film 1 and resin film 2 obtained by the cutting were left to stand at a temperature of 23? C. and a humidity of 30% RH for three hours, and then subjected to measurement of the surface roughness (Rz) on the interface side with a three dimensional roughness tester (KEYENCE CORPORATION, KS-1100, model number of head: LT-9510VM). The measurement was performed under the following conditions of the measurement ranges of X axis and Y axis set to 12500 ?m and 5000 ?m, respectively, the measuring pitch of both X axis and Y axis set to 10 ?m, the moving speed of 1000 ?m/sec, the temperature set to 23? C., and the humidity set to 30% RH. The surface roughness (Rz) on the interface side was calculated using analysis software (KEYENCE CORPORATION, KS-Analyzer) by a method in conformity with JIS B-0601 (1994). The cut off value upon measurement of the surface roughness was set to 2.5 mm. The surface roughness (Rz) was measured at a portion where no trace of cutting with the microtome, no contaminants, or no bubbling was observed. The average of measured values at three sites was employed as the surface roughness (Rz). It is to be noted that the measurement was completed within 360 minutes.
(66) (2) Measurement of Difference in Refractive Index of Interlayer Film
(67) The resin composition for protective layer was supplied to a twin-screw extruder to be molten and kneaded, and introduced to a T-die for widening. Then, the resin composition was ejected from the opening of the extruder and soon cooled to be solidified to give a thermoplastic resin film with a thickness of 760 ?m. The obtained thermoplastic resin film was left to stand at 23? C. and 30% RH for three hours. The thermoplastic resin was cut at a central portion in the width direction of the film to give a sheet piece in a size of 10 mm in width and 30 mm in length. The obtained sheet piece was subjected to measurement of the refractive index nD at D line (wavelength: 589.3 nm) using an Abbe's refractometer (Atago Co., Ltd., NAR-1T SOLID) at 25? C. in conformity with JIS K7142. The refractive index nD was taken as the refractive index of the resin composition for protective layer, namely, the refractive index of the first surface layer and the refractive index of the second surface layer. The refractive index nD of the resin composition for sound insulation layer was measured in the same manner, and the obtained refractive index nD was taken as the refractive index of the intermediate layer.
(68) (3) Measurement of 80? C. Creep Elongation Rate and 80? C. Creep Elastic Modulus of Interlayer Film
(69) The interlayer film for laminated glass having a predetermined cross-sectional area (8.1 mm.sup.2) was left at a temperature of 25? C. and a humidity of 25% RH for 24 hours so that the temperature and the moisture were conditioned. The resulting interlayer film for laminated glass was left at a predetermined temperature (80? C.) for 30 minutes while carrying a predetermined weight (20 g) on its lower end. The elongation of the interlayer film for laminated glass was measured and the 80? C. creep elongation rate (%) was calculated using the following equation:
80? C. creep elongation rate (%)=(Length after test (cm)?length before test (cm))/length before test (cm)?100.
(70) Based on the obtained 80? C. creep elongation rate, the 80? C. creep elastic modulus (MPa) was calculated using the following equation:
80? C. creep elastic modulus (MPa)=(Weight applied (N))/(initial cross-sectional area of test piece (mm.sup.2)?80? C. creep elongation rate (%)/100).
(4) Evaluation on Optical Distortion of Laminated Glass
(71) The laminated glass including the interlayer film for laminated glass (extension rate: 1 time) and the laminated glass including the interlayer film for laminated glass (extension rate: 1.2 times) obtained in each of the examples and comparative examples were irradiated with light emitted from a light source (halogen lamp) through a slit. The projective distortion on a screen was detected by a sensor (camera), and the distortion data was processed by a computer, thereby obtaining an optical distortion value. A higher optical distortion value is considered to indicate greater optical distortion (image distortion).
(72) The method for measuring the optical distortion value is specifically described in the following. 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 slit; 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 (15V100W) 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 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.
(73) For the use as a windshield for automobiles, the optical distortion is desired to be less than 1.8 when the extension rate is 1 time and the ratio of the optical distortion when the extension rate is 1.2 time to the optical distortion when the extension rate is 1 time (optical distortion when the extension rate is 1.2 time/optical distortion when the extension rate is 1 times) is required to be 1.2 or less. For another application such as a laminated glass for architectures, the optical distortion when the extension rate is 1 time is preferably 3 or less, and the optical distortion when the extension rate is preferably 1.2 times is 5 or less.
(74) TABLE-US-00001 TABLE 1 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Film thickness (?m) First surface layer 340 340 340 340 340 340 315 Intermediate layer 100 100 100 100 100 100 70 Second surface layer 370 370 370 370 370 370 400 Condition for forming Roughness of embossing 10 10 10 10 5 15 30 minute recesses and pattern (?m) minute projections Condition for forming Temperature of laminate 95 80 80 100 80 recesses in the shape of (? C.) engraved line Roughness of embossing 31 35 34 35 45 pattern (?m) Evaluation Surface roughness Rz of resin film 1 (?m) 0.52 0.79 0.55 0.81 0.88 0.69 1.87 Surface roughness Rz of resin film 2 (?m) 0.5 0.7 0.54 0.8 0.75 0.45 1.35 Difference in refractive index 0.0094 0.0093 0.092 0.0093 0.0092 0.0093 0.0094 80? C. creep elongation rate (%) 55 55 40 55 55 55 55 80? C. creep elastic modulus (MPa) 0.044 0.044 0.061 0.044 0.044 0.044 0.045 Optical distortion value 1.4 1.7 1.55 1.8 1.6 1.37 2.5 (extension rate: 1 time) Optical distortion value 1.61 1.98 1.76 2.54 1.87 1.45 2.95 (extension rate: 1.2 times) Comparative Comparative Example 8 Example 9 Example 10 Example 1 Example 2 Film thickness (?m) First surface layer 345 337 337 290 340 Intermediate layer 100 103 103 100 100 Second surface layer 350 382 382 415 370 Condition for forming Roughness of embossing 10 10 25 10 10 minute recesses and pattern (?m) minute projections Condition for forming Temperature of laminate 80 80 120 100 recesses in the shape of (? C.) engraved line Roughness of embossing 60 34 35 35 pattern (?m) Evaluation Surface roughness Rz of resin film 1 (?m) 0.57 0.48 0.92 2.5 2.6 Surface roughness Rz of resin film 2 (?m) 0.49 0.46 0.81 2.4 2.5 Difference in refractive index 0.0092 0.0091 0.0091 0.0095 0.0097 80? C. creep elongation rate (%) 55 55 55 100 250 80? C. creep elastic modulus (MPa) 0.045 0.043 0.043 0.024 0.01 Optical distortion value 1.45 1.35 1.54 8 8.4 (extension rate: 1 time) Optical distortion value 1.48 1.35 1.79 15 18 (extension rate: 1.2 times)
INDUSTRIAL APPLICABILITY
(75) The present invention can provide an interlayer film for laminated glass having small optical distortion while having a multilayer structure of two or more layers, and a laminated glass including the interlayer film for laminated glass.