Polyvinyl alcohol polymer film and process for producing same

Abstract

A PVA film that satisfies expressions (I) and (II), which has satisfactory stretchability and from which a polarizing film can be efficiently produced; and a process for film production which comprises (a) ejecting a PVA-containing film formation dope in a film form onto the first drying roll of a film formation device equipped with a plurality of drying rolls, partly drying the web, and then successively drying the web with the subsequent drying rolls to produce a film, wherein (b) the ratio of the peripheral speed (ST) of the drying roll on which the volatile content of the PVA film has fallen to 13 mass% to the peripheral speed (S1) of the first drying roll, ST / S1, is regulated to 0.990-1.050, (c) the ratio of the peripheral speed (SL) of the last drying roll to the peripheral speed ST, SL / ST, is regulated to 0.960-0.980, and (d) the SL / S1 ratio is regulated to 0.970-1.010. n(MD)Ave-0.110-3= n(TD)Ave= n(MD)Ave+0.2510-3 (I) n(TD)Ave=2.510-3 (II) [In the expressions, n(MD)Ave indicates the value obtained by averaging the machine-direction birefringence values of the PVA film with respect to the film thickness direction, and n(TD)Ave indicates the value obtained by averaging the transverse-direction birefringence values of the PVA film with respect to the film thickness direction.

Description

[0001] This application is a divisional application of the invention patent application with the national application number 201280015847.6 filed on September 27, 2013, and the invention title is "polyvinyl alcohol-based polymer film and its manufacturing method". technical field

[0002] The present invention relates to a polyvinyl alcohol-based polymer film, a method for producing the film, and a polarizing film made of the film. More specifically, the present invention relates to a film that has a high ultimate stretching ratio, is not easily broken even if the film is stretched at a high ratio, does not cause interruption of the stretching operation due to film breakage, and can be produced with high yield and good productivity. A polyvinyl alcohol-based polymer film for producing a stretched film having excellent optical properties such as polarizing properties, a method for producing the same, and a polarizing film made of the film. Background technique

[0003] A pola...

Examples

Embodiment 1

[0206] (1) Manufacture of PVA film:

[0207] (i) The proportion of volatile components composed of 100 parts by mass of PVA obtained by saponification of polyvinyl acetate (saponification degree 99.9 mol%, polymerization degree 2400), 12 parts by mass of glycerin, 0.1 part by mass of lauric acid diethanolamide, and water The film-forming stock solution that is 66% by mass is discharged to the first drying roller (93° C. of surface temperature, peripheral speed (S 1 ) 16.7m / min), while spraying hot air of 90°C at a wind speed of 5m / sec on the first drying roller to the entire non-contact surface of the first drying roller, while drying until the moisture ratio reaches 18% by mass, then, from the first drying roller The first drying roll is peeled off, and the drying after the second drying roll is carried out under the condition of the roll surface temperature of about 85 ° C, so that the surface and back of any part of the PVA film are alternately contacted with each drying ro...

Embodiment 2～5

[0223] (1) In Example 1, a PVA film was produced in the same manner as in Example 1 (1) by changing the film-forming conditions when producing the PVA film as described in Table 1 below. However, in Example 2, 100 parts by mass of PVA obtained by saponification of polyvinyl acetate (saponification degree 99.9 mol%, polymerization degree 2400), 12 parts by mass of glycerin, diethyl laurate A film-forming stock solution having a volatile component ratio of 73% by mass consisting of 0.1 parts by mass of amide and water.

[0224] The Δn(MD) of each PVA film thus obtained was measured by the method described above. Ave , Δn(TD) Ave , mass swelling degree and ultimate stretch ratio, the results are shown in Table 1 below.

[0225] (2) Using a test piece in the longitudinal direction (MD)×width direction (TD)=10cm×5cm collected from the central portion of each PVA film obtained in the above (1) in the width direction (TD), carry out the same procedure as in Example 1. (2) The same...

[0001] This application is a divisional application of the invention patent application with the national application number 201280015847.6 filed on September 27, 2013, and the invention title is "polyvinyl alcohol-based polymer film and its manufacturing method". technical field

[0002] The present invention relates to a polyvinyl alcohol-based polymer film, a method for producing the film, and a polarizing film made of the film. More specifically, the present invention relates to a film that has a high ultimate stretching ratio, is not easily broken even if the film is stretched at a high ratio, does not cause interruption of the stretching operation due to film breakage, and can be produced with high yield and good productivity. A polyvinyl alcohol-based polymer film for producing a stretched film having excellent optical properties such as polarizing properties, a method for producing the same, and a polarizing film made of the film. Background technique

[0003] A pola...

Examples

Embodiment 1

[0206] (1) Manufacture of PVA film:

[0207] (i) The proportion of volatile components composed of 100 parts by mass of PVA obtained by saponification of polyvinyl acetate (saponification degree 99.9 mol%, polymerization degree 2400), 12 parts by mass of glycerin, 0.1 part by mass of lauric acid diethanolamide, and water The film-forming stock solution that is 66% by mass is discharged to the first drying roller (93° C. of surface temperature, peripheral speed (S 1 ) 16.7m / min), while spraying hot air of 90°C at a wind speed of 5m / sec on the first drying roller to the entire non-contact surface of the first drying roller, while drying until the moisture ratio reaches 18% by mass, then, from the first drying roller The first drying roll is peeled off, and the drying after the second drying roll is carried out under the condition of the roll surface temperature of about 85 ° C, so that the surface and back of any part of the PVA film are alternately contacted with each drying ro...

Embodiment 2～5

[0223] (1) In Example 1, a PVA film was produced in the same manner as in Example 1 (1) by changing the film-forming conditions when producing the PVA film as described in Table 1 below. However, in Example 2, 100 parts by mass of PVA obtained by saponification of polyvinyl acetate (saponification degree 99.9 mol%, polymerization degree 2400), 12 parts by mass of glycerin, diethyl laurate A film-forming stock solution having a volatile component ratio of 73% by mass consisting of 0.1 parts by mass of amide and water.

[0224] The Δn(MD) of each PVA film thus obtained was measured by the method described above. Ave , Δn(TD) Ave , mass swelling degree and ultimate stretch ratio, the results are shown in Table 1 below.

[0225] (2) Using a test piece in the longitudinal direction (MD)×width direction (TD)=10cm×5cm collected from the central portion of each PVA film obtained in the above (1) in the width direction (TD), carry out the same procedure as in Example 1. (2) The same...

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