Colored low-polarizing films, colored low-polarizing sheets, and colored low-polarizing lenses, and methods thereof

Abstract

A colored low-polarizing film of a desired color is produced by causing a polyvinyl alcohol film to swell with water, stretching, dyeing with an organic dichroic dye, and drying it; a polarizing sheet including the film and transparent sheets attached to both sides of the film by an adhesive; and an injection-molded polarizing lens obtained by causing the sheet to curve to impart spherical or aspherical surfaces to obtain a curved polarizing lens and injecting a transparent resin onto the concave surface of the lens. The dye includes a dichroic organic dye and a coloration organic dye, wherein the dichroic composition includes a combination of dichroic dyes having a dichroic ratio of 13 or higher, wherein the coloration dye composition includes a combination of dyes having an extremely low dichroic ratio, of 4 or less, or substantially having no dichroic ratio.

Claims

1. A colored low-polarizing film produced by causing, a polyvinyl alcohol film to swell with water, uniaxially stretching it, dyeing it with a dichroic organic dye composition and a coloration organic dye composition, and drying it, wherein the dichroic organic dye composition comprises a combination of dichroic organic dyes having a dichroic ratio of 13 or higher, wherein the coloration organic dye composition comprises a combination of dyes having an extremely low dichroic ratio, of 4 or less, or substantially having no dichroic ratio, wherein the dichroic organic dyes of the dichroic organic dye composition are selected so as to be colorless and contribute to obtain the polarizing degree of interest, wherein the dyes of the coloration organic dye composition are selected so as to have color of interest, wherein because of a low or no dichroic ratio of the coloration organic dye composition, the film shows a small change in color tone during a heating process, and wherein the polarizing degree of the film is 45% to less than 90%.

2. The colored low-polarizing film of claim 1, wherein the dichroic organic dye composition is used in an amount necessary to obtain the lower limit of the required dichroic ratio.

3. The colored low-polarizing film of claim 1, wherein the coloration organic dye composition is used in an amount such that the transmittance of the film is 8% to 50% and is at least 5% less than the transmittance of a polarizing film obtained by using the dichroic organic dye composition only.

4. A method for producing a colored low-polarizing film by causing a polyvinyl alcohol film to swell with water, uniaxially stretching it, dyeing it with a a dichroic organic dye composition and a coloration organic dye composition, and drying it, wherein the dichroic organic dye composition comprises a combination of dichroic organic dyes having a dichroic ratio of 13 or higher, wherein the coloration organic dye composition comprises a combination of dyes having an extremely low dichroic ratio of 4 or less or substantially having no dichroic ratio, wherein the dichroic organic dyes of the dichroic organic dye composition are selected so as to be colorless and contribute to obtain the polarizing degree of interest, wherein the dyes of the coloration organic dye composition are selected so as to have color of interest, wherein because of the low or no dichroic ratio of the coloration organic dye composition, the film shows the small change in color tone during a heating process, and wherein the polarization degree of the film is 45% to less than 90%.

5. The method for producing the colored low-polarizing film of claim 4, wherein the dichroic organic dye composition and the coloration organic dye composition are used in a separated aqueous solution.

6. The method for producing the colored low-polarizing film of claim 4, wherein the dichroic organic dye composition is used in an amount necessary to obtain the lower limit of the required dichroic ratio.

7. The method for producing the colored low-polarizing film of claim 4, wherein the coloration organic dye composition is used in an amount such that the transmittance of the film is 8% to 50% and is at least 5% less than the transmittance of a polarizing film obtained by using the dichroic organic dye composition only.

8. A colored low-polarizing sheet that comprises a polarizing film produced by causing a polyvinyl alcohol film to swell with water, uniaxially stretching it, dyeing it with a dichroic organic dye composition and a coloration organic dye composition, and drying it, and transparent sheets being attached on both sides of the polarizing film by an adhesive, wherein the dichroic organic dye composition comprises a combination of dichroic organic dyes having a dichroic ratio of 13 or higher, wherein the coloration organic dye composition comprises a combination of dyes having an extremely low dichroic ratio, of 4 or less, or substantially having no dichroic ratio, wherein the dichroic organic dyes of the dichroic organic dye composition are selected so as to be colorless and contribute to obtain the polarizing degree of interest, wherein the dyes of the coloration organic dye composition are selected so as to have color of interest, wherein because of the low or no dichroic ratio of the coloration organic dye composition, the film shows the small change in color tone during a heating process, and wherein the polarizing film is a colored low-polarizing film of a desired color that has a polarizing degree of 45% to less than 90%.

9. The colored low-polarizing sheet of claim 8, wherein the dichroic organic dye composition and the coloration organic dye composition are used in a separated aqueous solution.

10. The colored low-polarizing sheet of claim 8, wherein the dichroic organic dye composition is used in an amount necessary to obtain the lower limit of the required dichroic ratio.

11. The colored low-polarizing sheet of claim 8, wherein the coloration organic dye composition is used in an amount such that the transmittance of the film is 8% to 50% and is at least 5% less than the transmittance of a polarizing film obtained by using the dichroic organic dye composition only.

12. The colored low-polarizing sheet of claim 8, wherein the transparent sheets are one or more resins selected from the group consisting of: aromatic polycarbonates, polyacrylates, acetylcelluloses, and a composition of an aromatic polycarbonate and an alicyclic polyester.

13. The colored low-polarizing sheet of claim 8, wherein the transparent plastic sheets are an aromatic polycarbonate sheet and the polarizing sheet is from 0.1 mm to 1 mm thick at 3000 nm or higher retardation.

14. The colored low-polarizing sheet of claim 8, wherein the adhesive is a two-liquid-type thermosetting polyurethane resin that consists of a curative agent that comprises a polyurethane prepolymer and a hydroxyl (poly) acrylate.

15. A colored low-polarizing lens obtained by: (1) laminating a transparent plastic sheet via an adhesive layer to each surface of the colored low-polarizing film of claim 1 to obtain a polarizing sheet, (2-1) causing the polarizing sheet to curve so as to impart spherical or aspherical surfaces thereto to obtain a curved polarizing lens, or (2-2) causing the polarizing sheet to curve so as to impart spherical or aspherical surfaces thereto and injecting a transparent resin onto the a concave surface to obtain an injection-molded lens, wherein the surface of one side of the polarizing sheet is a colored low-polarizing sheet that has 45% to less than 90% of a polarizing degree and that side is curved to make a concave surface.

16. The colored low-polarizing lens of claim 15, wherein the dichroic organic dye composition and the coloration organic dye composition are used in a separated aqueous solution.

17. The colored low-polarizing lens of claim 15, wherein the dichroic organic dye composition is used in an amount necessary to obtain the lower limit of a required dichroic ratio.

18. The colored low-polarizing lens of claim 15, wherein the coloration organic dye composition is used in an amount such that a transmittance of the film is 8% to 50% and is at least 5% less than the transmittance of a polarizing film obtained by using the dichroic organic dye composition only.

19. The colored low-polarizing lens of claim 15, wherein the transparent plastic sheet is one or more selected from the group consisting of: aromatic polycarbonates, polyacrylates, acetylcelluloses, and a composition of an aromatic polycarbonate and an alicyclic polyester.

20. The colored low-polarizing lens of claim 15, wherein the transparent plastic sheet is an aromatic polycarbonate sheet and the polarizing sheet is from 0.1 mm to 1 mm thick at 3000 nm or higher retardation.

21. The colored low-polarizing lens of claim 15, wherein the adhesive layer is a two-liquid-type thermosetting polyurethane resin that consists of a curative agent that comprises a polyurethane prepolymer and a hydroxyl (poly) acrylate.

Description

EXAMPLES

(A) Producing Polarizing Films

(1) Below, the preferable embodiments are explained.

(2) As the dyes that comprise the dichroic organic dye composition that imparts polarizations and the coloration organic dye composition that imparts color tones, those listed below were used. The concentrations of the dyes to be used and the dichroic ratios of them were determined based on the results of optical measurements of a monoaxially stretched PVA film that was stained by using each dye. For reference, the determined dichroic ratio is shown in parentheses after the dye's name.

Examples 1-5 and the Referenced Example

(1) Dichroic Organic Dye Composition

(3) Dichroic organic dye composition A:

(4) Blue 1: C.I.Direct Blue 237 (19.9); Red 1: C.I.Direct Red 81 (22.0); and Yellow 1: C.I.Direct Orange 39 (23.6)

(5) Dichroic organic dye composition B:

(6) Blue 2: C.I.Direct Blue 78 (9.2); Red 2: C.I.Direct Red 254 (10.9); and Yellow 2: C.I.Direct Yellow 12 (9.0)

(2) Coloration Organic Dye Composition

(7) Coloration organic dye composition a:

(8) Blue 3: Kayacion Blue CF-BL (1.3); Red 3: Novacron Red C-2G (1.4); and Yellow 3: C.I.Reactive Yellow 145 (2.6)

(9) Coloration organic dye composition b:

(10) Blue 4: C.I.Direct Blue 86 (1.7); Red 4: C.I.Direct Red 225 (2.5); and Yellow 4: C.I Mordant Yellow8 (1.7)

(11) Coloration organic dye composition c:

(12) Blue 4: C.I.Direct Blue 86 (1.7); Blue 5: C.I.Direct Blue 108 (1.6); Red 5: C.I.Direct Red 227 (1.6); and Yellow 5: C.I Mordant Yellow 5 (2.5)

(13) By the method explained below the determination of the dichroic ratio of each organic dye was carried out.

(14) The Dichroic Ratios of the Organic Dyes:

(15) (Production of Samples to be Measured)

(16) The dichroic ratios of the dichroic organic dyes and the coloration organic dyes of the present invention were estimated by the method for measurement of the polarizing film dyed by each dye, instead of using a method using iodine under conditions to obtain 60 or more of a dichroic ratio if the polarizing film were stained by iodine.

(17) (The Method for Measurement)

(18) For each dye a polarizing film was produced and the dichroic ratio was measured. The following formula and the value of each dye at its maximum absorption wavelength were used to calculate the dichroic ratio.
The dichroic ratio=Az/Ax
where Ax represents the absorbance of linearly-polarized light in the maximum transmission direction, and Az represents the absorbance of linearly-polarized light in a direction perpendicular to the maximum transmission direction. Ax and Az were measured by allowing the linearly-polarized light to be incident to the sample, using a spectrophotometer manufactured by Shimadzu Corporation (UV-3600).

(3) Producing Polarizing Film

(19) Polyvinyl alcohol (PVA) (Kuraray Co., Ltd., trade name: VF-PS#7500) was caused to swell in water at 35° C. for 270 seconds while it was being stretched two-fold.

(20) After that, the PVA was dyed in an aqueous solution containing the dye compositions listed in Table 1 and 10 g/L of anhydrous sodium sulfate at 35° C. During this process, it was further stretched. This dyed film was immersed in an aqueous solution containing 2.3 g/L of nickel acetate and 4.4 g/L of boric acid at 35° C. for 120 seconds while being stretched 5.6-fold. The film was dried at room temperature for 3 minutes in a state where the tension was maintained, and then subjected to a heat treatment at 110° C. for 3 minutes, whereby a polarizing film was obtained.

(21) The constituents and the amounts of the dichroic organic dye compositions and the coloration organic dye compositions are listed in Table 1 below.

(22) Calculated value: values obtained by a calculation based on the results of the measurements explained above for each organic dye without considering any interaction when the plural organic dyes are used at the same time;

(23) Measured value: values obtained from experiments carried out based on the calculated value;

(24) After color adjustment (Example 1): values obtained by adjusting the concentration of the coloration organic dye compositions: The concentration is mainly controlled so as to obtain the transmittance of interest.

(25) After adjustment: values of the concentrations of the dichroic organic dye compositions and the coloration organic dye compositions were adjusted so as to have the transmittance and the degree of polarization of interest: The concentrations of the dichroic organic dye compositions were mainly increased to obtain the transmittance of interest. The concentrations of the coloration organic dye compositions were mainly decreased to obtain the degree of polarization of interest.

(26) Next, the degree of polarization and the color tones of the obtained polarizing films are shown in Table 2. The degree of polarization was obtained by the following formula:
Degree of polarization=100×(τpmax−τpmin)/(τpmax+τpmin),
wherein, τpmax is the maximum value of luminous transmittance measured by the incident of linearly polarized light and τpmin is the minimum value of luminous transmittance measured by the incident of linearly polarized light. τpmax and τpmin are the values that express Ax and Az as the luminous transmittance.

(27) Based on the results of Example 1, the changes of the color and the polarizing degree of Examples 2-5 were considered to show the same changes as for Example 1. Further, it was found that the coloration polarizing dyes, which show low dichroic ratios, increase the polarizing degree to the extent that it is not negligible. Thus, based on the measured values the compositional ratios after the color adjustment and after the polarizing degree adjustment were estimated and produce the films of the examples. The tolerances of colors (L*, a*, and b*) are ±2%. The tolerance of the polarizing degree is ±3%. Examples 3, 4, and 5 were embodiments where the same processes were repeated. From these examples one can see the reproducibility of the method for producing the polarizing film of the present invention.

(28) TABLE-US-00001 TABLE 1 Dichroic organic dye composition (g/L) Blue1/ Red 1/ Yellow1/ Coloration organic dye composition (g/L) Type Blue 2 Red 2 Yellow2 Type Blue3 Blue4 Blue5 Red3 Red4 Red5 Yellow3 Yellow4 Yellow5 Exam- Calculated A 0.110 0.015 0.036 c 0.089 0.358 0.336 0.419 ple value 1 Measured ″ ″ ″ ″ ″ ″ ″ value After color ″ ″ ″ 0.200 0.799 0.540 0.964 adjustment After 0.066 0.009 0.018 ″ adjustment Exam- Calculated A 0.555 0.008 0.018 b 0.391 0.336 0.419 ple value 2 Measured ″ ″ ″ ″ ″ ″ value After 0.044 0.006 0.014 1.097 0.400 1.040 adjustment Exam- Calculated A 0.187 0.025 0.062 a 0.223 0.212 0.214 ple value 3 Measured ″ ″ ″ ″ ″ ″ value After 0.178 0.024 0.059 0.533 0.384 0.555 adjustment Exam- Calculated A 0.152 0.023 0.054 a 0.401 0.266 0.289 ple value 4 Measured ″ ″ ″ ″ ″ ″ value After 0.128 0.017 0.041 0.617 0.496 0.640 adjustment Exam- Calculated A 0.187 0.025 0.062 b 0.223 0.212 0.214 ple value 5 Measured ″ ″ ″ ″ ″ ″ value After 0.178 0.024 0.059 0.527 0.361 0.535 adjustment Refer- After B 0.940 0.110 0.130 ence adjustment Exam- ple

(29) TABLE-US-00002 TABLE 2 Transmit- Degree of tance Color tones polarization (%) L* a* b* (%) Example 1 Calculated value 19.6 51.4 −0.8 −3.4 61.0 Measured value 29.2 61.0 −1.0 −2.1 57.5 After color adjustment 20.0 51.9 −1.3 −3.5 65.2 After adjustment 19.5 81.2 −0.7 −1.6 60.3 Example 2 Calculated value 19.6 51.4 −0.8 −3.4 60.3 Measured value 30.1 61.8 5.3 −3.1 54.9 After adjustment 20.1 51.9 0.8 −1.4 62.9 Example 3 Calculated value 25.0 57.1 −0.8 −3.4 79.7 Measured value 34.2 65.1 1.5 −5.3 68.8 After adjustment 24.0 56.1 0.7 −0.3 80.3 Example 4 Calculated value 20.0 51.8 −0.8 −3.4 60.0 Measured value 27.2 59.2 −1.6 −5.8 62.0 After adjustment 20.3 52.1 −2.4 −2.5 59.7 Example 5 Calculated value 25.0 57.1 −0.8 −3.4 80.0 Measured value 34.2 65.1 1.5 −5.3 68.8 After adjustment 24.0 56.1 0.7 −3.0 80.3 Reference Example After adjustment 20.5 52.4 −1.6 −2.6 99.4

(30) As is clearly understood from these examples, in colored polarizing films that are produced by using the dichroic organic dye compositions, which show 13 or more of a dichroic ratio, and the coloration organic dichroic dye compositions, which show 4 or less of a dichroic color, polarizing films that have a transmittance of interest with an adjusted low degree of polarization can be produced. Next, by using the polarizing films obtained in Examples 4 and 5, an aromatic polycarbonate polarizing sheet was produced.

(B) Aromatic Polycarbonate Polarizing Sheet

(31) A urethane-based adhesive was applied to the polarizing film obtained in (A) using a bar coater #12, then dried at 70° C. for 10 minutes. After that, an aromatic polycarbonate sheet 0.3 mm thick and having a retardation value of 5,500 nm (Mitsubishi Gas Chemical Co., Inc.) was bonded to the polarizing film using a laminating machine so that both the stretch axis of the aromatic polycarbonate sheet and the stretch axis of the polarizing film were in a direction horizontal to the polarizing lens. The adhesive was applied to the polarizing film side of the laminated sheet in the same way as above, and another aromatic polycarbonate sheet was bonded thereto in the same way, whereby an aromatic polycarbonate polarizing sheet was obtained. The coated adhesive after curing was 9 to 11 μm thick.

(C) Measurement of Absorbance of Aromatic Polycarbonate Polarizing Lens

(32) The transmittance and the color tone of the prepared aromatic polycarbonate polarizing sheet were measured using a spectrophotometer manufactured by Shimadzu Corporation (UV-3600). The results are shown in Table 3.

(D) Aromatic Polycarbonate Polarizing Lens

(33) The aromatic polycarbonate polarizing sheet obtained in (B) was subjected to the curving process using a mold having a base curve of 7.95 (curvature radius: 66.67 mm). In the curving process, the forming was carried out under the following conditions: mold temperature: 137° C., and retention time: 1,200 seconds. The base curve as used herein refers to the curvature of the front surface of the lens, and it is a value obtained by dividing 530 by the curvature radius (in millimeters). There were no cracks in the polarizing film of the aromatic polycarbonate polarizing lens after the curving process. The transmittance and color tone of the aromatic polycarbonate polarizing lens after the curving process of the samples were measured in a way similar to that in (C). The color difference ΔE*ab in the CIE1976 (L*a*b*) color space before and after forming is shown in Table 3. The color difference was obtained by the following formula:
Color difference: ΔE*ab=((ΔL*)^2+(Δa*)^2+(Δb*)^2^(½)

(34) TABLE-US-00003 TABLE 3 Color tones of produced polycarbonate polarizing sheet before and after curving process Before curving process After curving process Color difference Polarizing Polarizing at curving Transmittance Color tone degree Transmittance Color tone degree process (%) L* a* b* (%) (%) L* a* b* (%) After-Before Example 4 20.0 51.8 −2.9 −1.5 57.6 20.3 52.2 −2.0 −2.0 55.2 1.1 Example 5 23.8 55.9 0.4 −3.0 79.4 23.9 56.0 −2.0 −3.8 78.7 2.5 Reference 20.3 52.2 −1.8 −2.5 99.3 17.4 48.7 −0.4 −2.4 99.1 3.7 Example

(35) As is clearly understood from these examples, in the aromatic polycarbonate polarizing sheet that was dyed by using the dichroic organic dye composition only, the color difference before and after the processing steps was 3.7. In contrast, the aromatic polycarbonate polarizing sheets that were dyed by using the dichroic organic dye composition and the coloration organic dyes composition showed that the color differences before and after the processing steps were 1.1 to 2.5. Thus, the polarizing sheet of the present invention shows small changes in color tone and transmittance before and after the processing steps.