Yellow Colorant Composition Having Improved Chroma And Hue, Pigment Composition Therefor, And Use Thereof

Abstract

Problem to be Solved

It is intended to provide a yellow colorant composition having improved chroma and lightness, a pigment composition therefor, and use thereof for forming images.

Solution

The present invention provides a colorant composition containing a yellow pigment, a yellow fluorescent dye, and a resin binder, wherein the maximum reflectance wavelength in the visible reflection spectrum of a coating film consisting of the fluorescent dye and the resin binder without comprising the yellow pigment falls within the range of 490 to 535 nm, and the maximum reflectance of the coating film is 90 to 140%.

Claims

1. A colorant composition comprising a yellow pigment, a yellow fluorescent dye, and a resin binder, wherein the maximum reflectance wavelength in the visible reflection spectrum of a coating film consisting of the fluorescent dye and the resin binder without comprising the yellow pigment falls within the range of 490 to 535 nm, and the maximum reflectance of the coating film is 90 to 140%.

2. A colorant composition as claimed in claim 1, wherein the hue angle of the yellow pigment falls within the range of 90 to 99°.

3. A colorant composition as claimed in claim 1, wherein the yellow pigment comprises one or more pigments selected from the group consisting of C.I. Pigment Yellow 74, C.I. Pigment Yellow 120, C.I. Pigment Yellow 155, C.I. Pigment Yellow 180, and C.I. Pigment Yellow 185.

4. A colorant composition as claimed in claim 1, wherein the absorption maximum wavelength of the yellow fluorescent dye falls within the range of 380 to 450 nm.

5. A colorant composition as claimed in claim 1, wherein the hue angle of a coating film consisting of the yellow fluorescent dye and the resin binder on white paper is larger than the hue angle of a coating film consisting of the yellow pigment and the resin binder on white paper.

6. A colorant composition as claimed in claim 1, wherein the yellow fluorescent dye comprises one or more dyes selected from the group consisting of a coumarin, a stilbene, and a naphthalimide.

7. A colorant composition as claimed in claim 1, wherein the yellow fluorescent dye comprises one or more dyes selected from the group consisting of C.I. Solvent Yellow 33, C.I. Solvent Yellow 98, C.I. Solvent Yellow 131, C.I. Solvent Yellow 135, and C.I. Solvent Yellow 160:1.

8. A colorant composition as claimed in claim 1, wherein the yellow fluorescent dye is present in an amount of 0.01 to 30 parts by mass relative to 100 parts by mass of the yellow pigment.

9. A colorant composition as claimed in claim 1, wherein the resin binder comprises one or more resins selected from the group consisting of a polyester, a polystyrene derivative, an acrylic resin derivative, and a urethane resin.

10. A colorant composition as claimed in claim 1, wherein when the colorant is applied onto white paper, the hue difference ΔE between the hue of the coating under the daylight color light source D65 (color temperature=6500° K) and the hue under the room light-type light source A10 (color temperature=3000° K) is 6.5 or less.

11. A pigment composition comprising a colorant composition, wherein the colorant composition contains a yellow pigment, a yellow fluorescent dye, and a resin binder, wherein the maximum reflectance wavelength in the visible reflection spectrum of a coating film consisting of the fluorescent dye and the resin binder without comprising the yellow pigment falls within the range of 490 to 535 nm, and the maximum reflectance of the coating film is 90 to 140% and wherein the pigment composition comprises 0.01 to 30 parts by mass of the yellow fluorescent dye relative to 100 parts by mass of the yellow pigment.

12. A pigment composition as claimed in claim 11 for forming images.

Description

EXAMPLES

[0071] Hereinafter, the present invention will be described with reference to Examples. However, the present invention is not intended to be limited by these examples.

Example 1

[0072] The following colorant composition was prepared.

TABLE-US-00001 TABLE 1 Yellow C.I. Pigment Yellow 180 0.6 parts by mass  pigment (trade name: Toner Yellow HG, manufactured by Clariant) Fluorescent Solvent Yellow 160: 1 0.0006 parts by mass dye (LANXESS AG, Macrolex, (0.1 part by mass Fluorescent Yellow 10GN) relative to 100 parts by mass of the yellow pigment) Polyester Reichhold Chemicals, Inc., product 10 parts by mass resin name: Finetone 382ES Solvent Tetrahydrofuran 20 parts by mass

[0073] 30 g of the composition described above was weighed and put into a 70-ml glass bottle. 70 g of glass beads having a diameter of 2 mm was weighed into the bottle and dispersed for 60 minutes using a vertical paint shaker to prepare pigment application sample (ink) A1. The ink thus prepared had a pigment concentration of 6%. This ink was developed onto coat paper (manufactured by Daio Paper Corp., trade name: Utrillo Coat, weighed amount: 157 g/m.sup.2) (actual value of whiteness measured with the spectrophotometer SPECTRO FLASH SF600: 86.05, hue in hue measurement mentioned later: L*=94.71, a*=1.24, and b*=0.77) using bar coater No. 2 and dried on a hot plate. The amount (wet) of a coating of the obtained application sample A1 was 12 μm. Furthermore, its yellow reflection density was 1.25 in a reflection density measurement apparatus (manufactured by Gretag-Macbeth Inc., SPECTOROEYE, gas filling-system tungsten lamp, illumination type A, no physical filter).

[0074] Here, the absorption maximum wavelength of the yellow fluorescent dye Solvent Yellow 160:1 was 420 nm.

Example 2

[0075] Pigment application sample A2 was obtained in the same way as in Example 1 except that the ratio of the yellow fluorescent dye Solvent Yellow 160:1 was set to 0.5 parts by mass relative to 100 parts by mass of the yellow pigment (PY180). Its yellow reflection density was 1.30.

Example 3

[0076] Pigment application sample A3 was obtained in the same way as in Example 1 except that the ratio of the yellow fluorescent dye Solvent Yellow 160:1 was set to 1 part by mass relative to 100 parts by mass of the yellow pigment (PY180). Its yellow reflection density was 1.34.

Example 4

[0077] Pigment application sample A4 was obtained in the same way as in Example 1 except that the ratio of the yellow fluorescent dye Solvent Yellow 160:1 was set to 2 parts by mass relative to 100 parts by mass of the yellow pigment (PY180). Its yellow reflection density was 1.39.

Example 5

[0078] Pigment application sample A5 was obtained in the same way as in Example 1 except that the ratio of the yellow fluorescent dye Solvent Yellow 160:1 was set to 5 parts by mass relative to 100 parts by mass of the yellow pigment (PY180). Its yellow reflection density was 1.46.

Example 6

[0079] Pigment application sample A6 was obtained in the same way as in Example 1 except that the ratio of the yellow fluorescent dye Solvent Yellow 160:1 was set to 10 parts by mass relative to 100 parts by mass of the yellow pigment (PY180). Its yellow reflection density was 1.55.

Example 7

[0080] Pigment application sample A7 was obtained in the same way as in Example 1 except that the ratio of the yellow fluorescent dye Solvent Yellow 160:1 was set to 20 parts by mass relative to 100 parts by mass of the yellow pigment (PY180). Its yellow reflection density was 1.62.

Example 8

[0081] Pigment application sample A8 was obtained in the same way as in Example 6 except that the yellow pigment was changed to C.I. Pigment Yellow 155 (Toner Yellow 3GP manufactured by Clariant). Its yellow reflection density was 1.83.

Example 9

[0082] Pigment application sample A9 was obtained in the same way as in Example 6 except that the yellow pigment was changed to C.I. Pigment Yellow 74 (Toner Yellow 5GXT manufactured by Clariant). Its yellow reflection density was 1.52.

Example 10

[0083] Pigment application sample A16 was obtained in the same way as in Example 5 except that the yellow fluorescent dye Solvent Yellow 160:1 was changed to Solvent Yellow 98 (Hostasol Yellow 3G manufactured by Clariant). Its yellow reflection density was 1.47.

Comparative Example 1

[0084] Comparative pigment application sample B1 containing no yellow fluorescent dye was obtained in the same way as in Example 1 except that the yellow fluorescent dye Solvent Yellow 160:1 was not added in Example 1.

Comparative Example 2

[0085] Comparative pigment application sample 82 was obtained in the same way as in Example 1 except that 35 parts by mass of the yellow fluorescent dye Solvent Yellow 160:1 relative to 100 parts by mass of the yellow pigment were added in Example 1.

Comparative Example 3

[0086] Comparative pigment application sample 83 containing no yellow fluorescent dye was obtained in the same way as in Example 8 except that the yellow fluorescent dye Solvent Yellow 160:1 was not added in Example 8 (Pigment Yellow 155).

Comparative Example 4

[0087] Comparative pigment application sample B4 containing no yellow fluorescent dye was obtained in the same way as in Example 9 except that the yellow fluorescent dye Solvent Yellow 160:1 was not added in Example 9 (Pigment Yellow 74).

Comparative Example 5

[0088] Comparative pigment application sample 85 was obtained in the same way as in Example 6 except that the non-fluorescent yellow dye Solvent Yellow 93 (Solvaperm yellow 2G manufactured by Clariant) was used instead of the yellow fluorescent dye Solvent Yellow 160:1 in Example 6.

Comparative Example 6

[0089] Comparative pigment application sample 86 was obtained in the same way as in Example 8 except that the non-fluorescent yellow dye Solvent Yellow 93 (Solvaperm yellow 2G manufactured by Clariant) was used instead of the yellow fluorescent dye Solvent Yellow 160:1 in Example 8.

Comparative Example 7

[0090] Comparative pigment application sample 87 was obtained in the same way as in Example 9 except that the non-fluorescent yellow dye Solvent Yellow 93 (Solvaperm yellow 20 manufactured by Clariant) was used instead of the yellow fluorescent dye Solvent Yellow 160:1 in Example 9.

[0091] (Evaluation of Pigment Application Sample)

[0092] The samples A1 to A10 according to the present invention and the comparative samples 81 to 87 thus obtained were evaluated for their properties described below by the following methods.

[0093] 1) Hue evaluation [0094] Color measurement was carried out at a viewing angle of 10° with D65 as a light source for measurement using a spectrophotometer [SPECTRA FLASH SF600 (manufactured by Data Color International)] to quantitatively evaluate lightness/chroma/hue (L*C*H*) or L*a*b*. In this context, the hue is based on the definition of the color system specified by CIE (International Commission on Illumination). Each sample for hue measurement was uniformly applied and dried under the conditions described above. The area of the sample was 7 cm.sup.2. Furthermore, for each case, a composition excluding the dye or the pigment from each composition of Examples and Comparative Examples was used to prepare an application sample consisting of the pigment and the resin without containing the dye and an application sample consisting of the dye and the resin without containing the pigment. The hue angles of these samples were also measured by the same method as above. The results are shown in Table 2.

[0095] 2) Evaluation of change in hue depending on light source [0096] In the hue evaluation mentioned above, the measurements were carried out using both the standard daylight color light source (D65; color temperature 6500° K) and the room light-type light source A10 (color temperature 3000° K, and the hue difference (ΔE) between them was evaluated. In this context, the relationship between ΔE and sensory evaluation differs depending on the evaluation method thereof, but, in general, at hue differences of 2 or less, colors are reportedly difficult to distinguish by human sight. Furthermore, at ΔE within the range of more than 2.5 to 6.5 or less, colors are perceived as almost the same colors in general impression unless compared side-by-side. At ΔE within the range of more than 6.5 to 13.0 or less, colors differ by approximately 1, for example, in the Munsell color chart. ΔE less than 2.5 was judged as being favorable; ΔE of 2.5 to 6.5 was judged as being tolerable; and ΔE more than 6.5 was judged as being inadequate.

[0097] 3) Measurement of visible reflectance and maximum reflection wavelength [0098] A solution containing the resin, the yellow fluorescent dye, and the solvent mixed without containing the yellow pigment was applied and dried in the same way as mentioned above to prepare a reflection spectrum measurement sample. The measurement was carried out at a viewing angle of 10° with the light source D65 as a light source for measurement using a spectrophotometer [SPECTRA FLASH SF600 (manufactured by Data Color International)]. In this respect, standard white ceramic tiles (manufactured by Data Color International, manufacture lot serial #9197, average reflectance of visible light at 500 nm or more; 90% or more) attached to the spectrophotometer were used as the reference. [0099] The obtained evaluation results are shown in Table 2.

[0100] The contents of Table 2 are summarized as follows, [0101] 1) The addition of 10 parts by mass of the yellow fluorescent dye Solvent Yellow 160:1 of the present invention relative to 100 parts by mass of Pigment Yellow 180 (Example 6) increases the chroma C by approximately 12. Furthermore, the hue angle H is changed by 3.8, and the lightness L is increased by 2.6. [0102] 2) The addition of 0.1 part by mass of the yellow fluorescent dye Solvent Yellow 160:1 of the present invention relative to 100 parts by mass of Pigment Yellow 180 (Example 1) was confirmed to have a chroma-improving effect such that the chroma C is increased by approximately 2.5. Furthermore, the hue angle H is changed by 0.01, and the lightness L is increased by 0.15. [0103] 3) As for the hue difference between different color light sources, the addition of approximately 20 parts by mass of the fluorescent dye causes ΔE to exceed 6 (Example 7), which is however a level that is generally not easy to recognize unless compared at the same site, and is considered sufficient for practical use. [0104] 4) An amount of the fluorescent dye added set to 35 parts by mass or more (Comparative Example 2) was considered to be unfavorable because decreasing tendency was found in the lightness and increase in the hue difference between different light sources was more than 6.5, though the chrome was high. The maximum reflectance wavelength in the visible reflection spectrum of a film consisting of the yellow fluorescent dye and the resin, excluding the yellow pigment from the composition of Comparative Example 2, was 536 nm. The reason why the hue difference in this Comparative Example 2 was a value as large as 6.78 was probably the shift of the reflection wavelength caused by the increase in the amount of the fluorescent dye added. [0105] 5) Furthermore, the addition of the non-fluorescent dye C.I. Solvent Yellow 93 was very low effective both for the chroma and for the lightness. Its advantage was concluded to be small in consideration of reduction in light resistance caused by the addition of the non-fluorescent dye.

TABLE-US-00002 TABLE 2 Part by mass of Y dye Maximum Maximum Hue relative to L* H Change in hue Hue reflectance reflectance angle of 100 parts of (light- C* (hue caused by light angle of dye wavelength of dye Example Pigment pigment Dye pigment ness) (chroma) angle) source (ΔE) of dye (%) (nm) 1 PY180 93.5 SY160:1 0.1 88.96 80.31 93.51 0.56 Favorable 120 106 496 2 PY180 93.5 SY160:1 0.5 89.23 93.37 93.54 1.23 Favorable 119 117 500 3 PY180 93.5 SY160:1 1 89.38 87.36 93.56 1.97 Favorable 117 121 506 4 PY180 93.5 SY160:1 2 89.87 89.54 94.29 3.54 Tolerable 115 126 509 5 PY180 93.5 SY160:1 5 90.38 90.10 96.13 4.76 Tolerable 112 124 514 6 PY180 93.5 SY160:1 10 91.44 90.23 97.34 5.81 Tolerable 107 120 521 7 PY180 93.5 SY160:1 20 90.66 93.90 96.82 6.43 Tolerable 106 115 524 8 PY155 96.5 SY160:1 10 91.91 89.90 98.84 1.66 Favorable 107 120 521 9 PY74 93.9 SY160:1 10 91.66 90.45 97.43 3.51 Tolerable 107 120 521 10  PY180 93.5 SY98 5 89.55 81.2 93.43 1.86 Favorable 113 114 528 1 Comp. PY180 93.5 — 0 88.81 77.86 93.50 0.01 Favorable — — — 2 Comp. PY180 93.5 SY160:1 35 90.26 95.84 95.82 6.78 Inadequate 105 113 536 3 Comp. PY155 96.5 — 0 89.76 76.18 96.51 0.01 Favorable — — — 4 Comp. PY74 93.9 — 0 87.43 79.45 93.94 0.02 Favorable — — — 5 Comp. PY180 93.5 SY93 10 89.81 78.81 93.30 0.01 Favorable 104 86 540 nm or more 6 Comp. PY155 96.5 SY93 10 89.98 77.13 95.53 0.03 Favorable 104 86 540 nm or more 7 Comp. PY74 93.9 SY93 10 87.73 79.75 93.44 0.02 Favorable 104 86 540 nm or more