Paper coating composition with improved fluorescent brighteners carriers

Abstract

A paper coating composition has therein an optical brightening agent (OBA) and a light body water-soluble non-ionic polysaccharide derivative, exhibiting a solution viscosity in water of less than 1500 cps when dissolved at 5% polymer concentration, wherein the paper coating provides improved optical brightness as compared to the same formulation without said non-ionic, polysaccharide derivative. A paper coated with this composition has an optical brightness value of greater than 70.

Description

technical field

[0001] The present invention relates to a paper coating composition for enhancing the optical brightness of coated paper. More specifically, the present invention relates to a paper coating composition having an improved carrier for optical brighteners which makes the system more effective. Background technique

[0002] Prior to the present invention, coated paper producers often desired high brightness in the final coated product in order to enhance the visual appearance of the paper. Accordingly, it has become common practice for paper producers to utilize high brightness pigments, such as calcium carbonate and titanium dioxide, and to incorporate fluorescent agents as components of paper coating formulations in order to increase the brightness of the paper. These fluorescent agents (commonly referred to as "optical brighteners") work by absorbing radiated light waves in the ultraviolet wavelengths of the spectrum and re-emitting th...

Examples

Embodiment 1

[0037] Embodiment 1 (the coating of 100% kaolin)

[0038] In this example, 100% kaolin was used as the pigment component of the paper coating. The paint formulations tested are shown in Table 1. A description of each of the water-soluble polymer optical brightener vehicles used in the individual paint tests is given in Table 2.

[0039] The final paper properties observed for papers treated with different formulations are listed in Tables 4 and 5.

[0040] In this test it was found that using ADMIRAL® 1089FS fluidized polymer suspension, i.e. low viscosity non-ionic hydroxyethyl cellulose and 1.0 part distyryl biphenyl fluorescent enhancer, at 0.5 part active polymer, based on pigment For all optical brightener carriers tested, the highest brightness and the second highest whiteness will be produced at this addition level. These results are listed in Table 3. Experimental ultra-low viscosity solutions of hydroxyethyl cellulose will give the highest whiteness results. Howe...

Embodiment 2

[0046] Embodiment 2 (50% kaolin: the coating of 50% calcium carbonate)

[0047] In this test series, 50% kaolin and 50% calcium carbonate were used together as the pigment component of the paint. The paper coating formulations tested are listed in Table 5. A description of each water soluble polymer / optical brightener vehicle is listed in Table 2. The final paper properties observed for papers treated with different formulations are listed in Tables 6-9. All paints were thickened to the target viscosity range of the paints by adding varying amounts of KelginLV sodium alginate.

[0048] Since coated papers are usually glossed using a supercalender, brightness and gloss results were measured for supercalendered samples. Supercalender conditions were: two passes, 100°F, 16.5 feet per minute, and 1600 pounds per linear inch.

[0049] It has been found that coated papers containing DSBP (an optical brightener) in the coating formulation and 0.5-1.0 parts based on pigment of low...

technical field

[0001] The present invention relates to a paper coating composition for enhancing the optical brightness of coated paper. More specifically, the present invention relates to a paper coating composition having an improved carrier for optical brighteners which makes the system more effective. Background technique

[0002] Prior to the present invention, coated paper producers often desired high brightness in the final coated product in order to enhance the visual appearance of the paper. Accordingly, it has become common practice for paper producers to utilize high brightness pigments, such as calcium carbonate and titanium dioxide, and to incorporate fluorescent agents as components of paper coating formulations in order to increase the brightness of the paper. These fluorescent agents (commonly referred to as "optical brighteners") work by absorbing radiated light waves in the ultraviolet wavelengths of the spectrum and re-emitting th...

Examples

Embodiment 1

[0037] Embodiment 1 (the coating of 100% kaolin)

[0038] In this example, 100% kaolin was used as the pigment component of the paper coating. The paint formulations tested are shown in Table 1. A description of each of the water-soluble polymer optical brightener vehicles used in the individual paint tests is given in Table 2.

[0039] The final paper properties observed for papers treated with different formulations are listed in Tables 4 and 5.

[0040] In this test it was found that using ADMIRAL® 1089FS fluidized polymer suspension, i.e. low viscosity non-ionic hydroxyethyl cellulose and 1.0 part distyryl biphenyl fluorescent enhancer, at 0.5 part active polymer, based on pigment For all optical brightener carriers tested, the highest brightness and the second highest whiteness will be produced at this addition level. These results are listed in Table 3. Experimental ultra-low viscosity solutions of hydroxyethyl cellulose will give the highest whiteness results. Howe...

Embodiment 2

[0046] Embodiment 2 (50% kaolin: the coating of 50% calcium carbonate)

[0047] In this test series, 50% kaolin and 50% calcium carbonate were used together as the pigment component of the paint. The paper coating formulations tested are listed in Table 5. A description of each water soluble polymer / optical brightener vehicle is listed in Table 2. The final paper properties observed for papers treated with different formulations are listed in Tables 6-9. All paints were thickened to the target viscosity range of the paints by adding varying amounts of KelginLV sodium alginate.

[0048] Since coated papers are usually glossed using a supercalender, brightness and gloss results were measured for supercalendered samples. Supercalender conditions were: two passes, 100°F, 16.5 feet per minute, and 1600 pounds per linear inch.

[0049] It has been found that coated papers containing DSBP (an optical brightener) in the coating formulation and 0.5-1.0 parts based on pigment of low...