Polyvinyl acetal resin film and film roll thereof, and laminate comprising same
The present invention relates to a polyvinyl acetal resin film, comprising a polyvinyl acetal resin material, wherein the polyvinyl acetal resin film has a thickness of 5 to 350 μm, and satisfies the following Formulae (1) and (2) where, comparing one surface and the other surface, a mean value of the 10-point average roughness of a rougher surface A and a mean value of the 10-point average roughness of a smoother surface B are defined as Rz1(a) μm and Rz2(a) μm, respectively: Rz 1( a )>1.1× Rz 2( a ) (1) 3> Rz 2( a ) (2), a value obtained by dividing the standard deviation of the 10-point average roughness of the surface A by Rz1(a) and a value obtained by dividing the standard deviation of the 10-point average roughness of the surface B by Rz2(a) are each 0 to 0.30, a viscosity of a toluene/ethanol (1:1, mass ratio) solution containing 10%-by-mass of a polyvinyl acetal resin contained in the polyvinyl acetal resin material, which is measured at 20° C. and 30 rpm using a Brookfield-type (B-type) viscometer, is 100 to 1,000 mPa·s, and the amount of a plasticizer in the polyvinyl acetal resin film is 0 to 20% by mass based on a total mass of the polyvinyl acetal resin film.
1. A polyvinyl acetal resin film, comprising a polyvinyl acetal resin material,
wherein
the polyvinyl acetal resin material comprises a polyvinyl acetal resin and optionally plasticizer,
the polyvinyl acetal resin film has a thickness of from 5 to 350 μm, and satisfies Formulae (1) and (2):
Rz 1( a )>1.1 ×Rz 2( a ) (1)
3> Rz 2( a ) (2),
where, comparing one surface and the other surface, a mean value of a 10-point average roughness of a rougher surface A and a mean value of a 10-point average roughness of a smoother surface B are defined as Rz1(a) μm and Rz2(a) μm, respectively and
a value obtained by dividing a standard deviation of the 10-point average roughness of the rougher surface A by Rz1 (a) and a value obtained by dividing a standard deviation of the 10-point average roughness of the smoother surface B by Rz2(a) are each from 0 to 0.30,
a viscosity of a toluene/ethanol (1:1, mass ratio) solution containing 10%-by-mass of the polyvinyl acetal resin, which is measured at 20° C. and 30 rpm using a Brookfield-type viscometer, is from 100 to 1,000 mPas, and
the polyvinyl acetal resin film comprises the plasticizer in an amount of from 0 to 20% by mass based on a total mass of the polyvinyl acetal resin film.
2. The polyvinyl acetal resin film according to claim 1 , further satisfying Formula (3):
Rz 1( a )<5 (3).
3. The polyvinyl acetal resin film according to claim 1 , further satisfying Formulae (4), (5) and (6):
0.7× Rz 1( a )≤ Rz 1( b )≤1.3× Rz 1( a ) (4)
0.7× Rz 2( a )≤ Rz 2( b )≤1.3× Rz 2( a ) (5)
Rz 1( b )> Rz 2( b ) (6)
where the mean value of the 10 -point average roughness of the rougher surface A and the mean value of the 10-point average roughness of the smoother surface B after the polyvinyl acetal resin film is maintained at 50° C. for 30 minutes are defined as Rz1 (b) μm and Rz2(b) μm, respectively.
4. The polyvinyl acetal resin film according to claim 1 , wherein the viscosity of the toluene/ethanol (1:1, mass ratio) solution containing 10%-by-mass of the polyvinyl acetal resin is 300 mPas or lower.
5. The polyvinyl acetal resin film according to claim 1 , wherein the viscosity of the toluene/ethanol (1:1, mass ratio) solution containing 10%-by-mass of the polyvinyl acetal resin is higher than 200 mPas.
6. The polyvinyl acetal resin film according to claim 1 , wherein the polyvinyl acetal resin has a molecular weight distribution of 2.7 or higher.
7. The polyvinyl acetal resin film according to claim 1 , wherein the polyvinyl acetal resin is a mixture of at least two polyvinyl acetal resins having different viscosity-average polymerization degrees, or an acetalized product of a mixture of at least two polyvinyl alcohol-based resins having different viscosity-average polymerization degrees.
8. A polyvinyl acetal resin film roll, comprising the polyvinyl acetal resin film according to claim 1 which is wound such that the rougher surface A side is on the inside.
9. A polyvinyl acetal resin film roll, comprising the polyvinyl acetal resin film according to claim 1 which is wound such that the rougher surface A side is on the outside.
10. A method of storing a polyvinyl acetal resin film roll, the method comprising:
storing the polyvinyl acetal resin film roll according to claim 8 at a temperature of from −20° C. to 60° C.
11. A functional layer-equipped polyvinyl acetal resin film, comprising a functional layer on at least one surface of the polyvinyl acetal resin film according to claim 1 .
12. The functional layer-equipped polyvinyl acetal resin film according to claim 11 , wherein the functional layer is a conductive layer.
13. The functional layer-equipped polyvinyl acetal resin film according to claim 12 , wherein a material constituting the conductive layer comprises silver or copper.
14. The functional layer-equipped polyvinyl acetal resin film according to claim 12 , wherein the conductive layer comprises plural linear conductive materials having a line width of from 1 to 30 μm.
15. A method of producing the functional layer-equipped polyvinyl acetal resin film according to claim 11 , the method comprising:
coating, printing, or laminating a material constituting the functional layer on at least one surface of the polyvinyl acetal resin film.
16. A laminate, comprising:
a transparent substrate; and
the polyvinyl acetal resin film according to claim 1 .
17. A laminate, comprising the polyvinyl acetal resin film according to claim 1 between plural transparent substrates.
18. The laminate according to claim 16 , further comprising a plasticized polyvinyl acetal resin layer.
19. The laminate according to claim 16 , wherein the transparent substrate is a glass.
20. A vehicle, comprising: a glass comprising the laminate according to claim 16 .