Formable and foamed aqueous compositions
Foamable aqueous compositions can be foamed and applied to porous substrates to make light-blocking dry opacifying elements. Such compositions have 0.05-15 weight % of porous particles; at least 20 weight % of a binder; at least 0.0001 weight % of additives (including a surfactant); water; and at least 0.001 weight % of an opacifying colorant. Each porous particle includes a continuous polymeric phase and discrete pores; a mode particle size of 2-50 μm; and a porosity of 20-70 volume %. The continuous polymeric phase T g is >80° C. and has a polymer viscosity of 80-500 centipoises at an ethyl acetate shear rate of 100 sec −1 at a concentration of 20 weight % at 25° C. The dry opacifying element light blocking value is at least 4 and has a luminous reflectance >40% as measured by the Y tristimulus value. The foamed aqueous composition has a foam density of 0.1-0.5 g/cm 3 .
1. A foamable aqueous composition that has at least 35% solids and up to and including 70% solids, and comprises:
(a) at least 0.05 weight % and up to and including 15 weight % of porous particles, each porous particle comprising a continuous polymeric phase and a first set of discrete pores dispersed within the continuous polymeric phase, the porous particles having a mode particle size of at least 2 μm and up to and including 50 μm and a porosity of at least 20 volume % and up to and including 70 volume %, and the continuous polymeric phase having a glass transition temperature greater than 80° C. and comprising a polymer having a viscosity of at least 80 centipoises and up to and including 500 centipoises at a shear rate of 100 sec −1 in ethyl acetate at a concentration of 20 weight % at 25° C.,
(b) at least 20 weight % of a binder material;
(c) at least 0.0001 weight % of one or more additives comprising at least one surfactant;
(d) water; and
(e) at least 0.001 weight % of an opacifying colorant different from all of the one or more (c) additives, which opacifying colorant absorbs electromagnetic radiation having wavelengths of from 350 nm to 800 nm,
all amounts based on the total weight of the foamable aqueous composition,
wherein the foamable aqueous composition can provide a dry opacifying layer having a light blocking value of at least 4 as well as a luminous reflectance that is greater than 40% as measured by the Y tristimulus value.
2. The foamable aqueous composition of claim 1 , wherein the continuous polymeric phase comprises at least 70 weight %, based on the total polymer weight in the continuous polymeric phase, of one or more polymers derived from one or more of cellulose acetate, cellulose butyrate, cellulose acetate butyrate, and cellulose acetate propionate.
3. The foamable aqueous composition of claim 1 , wherein the opacifying colorant is a carbon black that is present in an amount of at least 0.003 weight % and up to and including 0.2 weight %, based on the total weight of the foamable aqueous composition.
4. The foamable aqueous composition of claim 1 , comprising at least 0.5 weight % and up to and including 10 weight % of the porous particles that have a mode particle size of at least 3 μm and up to and including 30 μm, based on the total weight of the foamable aqueous composition.
5. The foamable aqueous composition of claim 1 having at least 40% solids and up to and including 60% solids, and wherein:
the continuous polymeric phase comprises at least 70 weight % and up to and including 100 weight %, based on the total polymer weight in the continuous polymeric phase, of one or more polymers derived from one or more of cellulose acetate, cellulose butyrate, cellulose acetate butyrate, and cellulose acetate propionate;
the porous particles are present in an amount of at least 0.5 weight % and up to and including 10 weight %;
the binder material is present in an amount of at least 30 weight % and up to and including 50 weight % and has a glass transition temperature of less than 25° C.;
the one or more (c) additives further comprise an optical brightener in an amount of at least 0.01 weight % and up to and including 2 weight %; and
carbon black is present as at least one opacifying colorant in an amount of at least 0.003 weight % and up to and including 0.2 weight %,
all amounts being based on the total weight of the foamable aqueous composition.
6. The foamable aqueous composition of claim 1 , wherein the one or more (c) additives further comprise an optical brightener that is present within: the continuous polymeric phase of the porous particles; a volume of the first set of discrete pores; or both the volume of the first set of discrete pores and the continuous polymeric phase of the porous particles.
7. The foamable aqueous composition of claim 1 , wherein the one or more (c) additives further comprise metal flakes that are present within the porous particles.
8. The foamable aqueous composition of claim 1 , wherein the at least one surfactant of the one or more (c) additives is a foaming agent and the one or more (c) additives further comprise a foam stabilizing agent.
9. The foamable aqueous composition of claim 1 , wherein the one or more (c) additives further comprise a tinting colorant that is present in an amount of least 0.0001 weight % and up to and including 3 weight %, based on the total weight of the foamable aqueous composition.
10. The foamable aqueous composition of claim 1 , wherein the one or more (c) additives comprise an optical brightener in an amount of at least 0.01 weight % and up to and including 2 weight %, based on the total weight of the foamable aqueous composition.
11. The foamable aqueous composition of claim 1 , wherein the one or more (c) additives comprise two or more materials selected from a foaming agent, a foam stabilizing agent, a tinting colorant, an optical brightener, a flame retardant, an antimicrobial agent, and an inorganic filler.
12. A foamed aqueous composition that has at least 35% solids and up to and including 70% solids, and comprises:
(a) at least 0.05 weight % and up to and including 15 weight % of porous particles, each porous particle comprising a continuous polymeric phase and a first set of discrete pores dispersed within the continuous polymeric phase, the porous particles having a mode particle size of at least 2 μm and up to and including 50 μm and a porosity of at least 20 volume % and up to and including 70 volume %, and the continuous polymeric phase having a glass transition temperature greater than 80° C. and comprising a polymer having a viscosity of at least 80 centipoises and up to and including 500 centipoises at a shear rate of 100 sec −1 in ethyl acetate at a concentration of 20 weight % at 25° C.,
(b) at least 20 weight % of a binder material;
(c) at least 0.0001 weight % of one or more additives comprising at least one surfactant;
(d) water; and
(e) at least 0.001 weight % of an opacifying colorant different from all of the one or more (c) additives, which opacifying colorant absorbs electromagnetic radiation having wavelengths of from 350 nm to 800 nm,
all amounts based on the total weight of the foamed aqueous composition, and wherein
the foamed aqueous composition having a foam density of at least 0.1 g/cm 3 and up to and including 0.5 g/cm 3 , and
the foamed aqueous composition can provide a dry opacifying layer having a light blocking value of at least 4 as well as a luminous reflectance that is greater than 40% as measured by the Y tristimulus value.
13. The foamed aqueous composition of claim 12 , having a foam density of at least 0.15 g/cm 3 and up to and including 0.4 g/cm 3 .
14. The foamed aqueous composition of claim 12 , wherein the continuous polymeric phase comprises at least 70 weight %, based on the total polymer weight in the continuous polymeric phase, of one or more polymers derived from one or more of cellulose acetate, cellulose butyrate, cellulose acetate butyrate, and cellulose acetate propionate.
15. The foamed aqueous composition of claim 12 , wherein the opacifying colorant is a carbon black that is present in an amount of at least 0.003 weight % and up to and including 0.2 weight %, based on the total weight of the foamed aqueous composition.
16. The foamed aqueous composition of claim 12 , wherein the porous particles have a mode particle size of at least 3 μm and up to and including 20 μm.
17. The foamed aqueous composition of claim 12 having at least 40% solids and up to and including 60% solids, and wherein:
the continuous polymeric phase comprises at least 70 weight % and up to and including 100 weight %, based on the total polymer weight in the continuous polymeric phase, of one or more polymers derived from one or more of cellulose acetate, cellulose butyrate, cellulose acetate butyrate, and cellulose acetate propionate;
the porous particles are present in an amount of at least 0.5 weight % and up to and including 10 weight %;
the binder material is present in an amount of at least 30 weight % and up to and including 50 weight % and has a glass transition temperature of less than 25° C.;
the one or more (c) additives further comprise an optical brightener that is present in an amount of at least 0.01 weight % and up to and including 2 weight %; and
carbon black is present as at least one opacifying colorant in an amount of at least 0.003 weight % and up to and including 0.2 weight %,
all amounts based on the total weight of the foamed aqueous composition.
18. The foamed aqueous composition of claim 12 , wherein the one or more (c) additives further comprise an optical brightener that is present within:
the continuous polymeric phase of the porous particles; a volume of the first set of discrete pores; or both the volume of the first set of discrete pores and the continuous polymeric phase of the porous particles.
19. The foamed aqueous composition of claim 12 , wherein the at least one surfactant of the one or more (c) additives is a foaming agent and the one or more (c) additives further comprise a foam stabilizing agent.
20. The foamed aqueous composition of claim 12 , wherein the one or more (c) additives further comprise a tinting colorant that is present in an amount of least 0.0001 weight % and up to and including 3 weight %, based on the total weight of the foamed aqueous composition.
21. The foamed aqueous composition of claim 12 , wherein the one or more (c) additives further comprise an optical brightener that is present in an amount of at least 0.01 weight % and up to and including 2 weight %, based on the total weight of the foamed aqueous composition.
22. The foamed aqueous composition of claim 12 , wherein the one or more (c) additives comprise two or more materials selected from a foaming agent, a foam stabilizing agent, a tinting colorant, an optical brightener, a flame retardant, an antimicrobial agent, and an inorganic filler.
23. The foamed aqueous composition of claim 12 , wherein the one or more (c) additives further comprise an antimicrobial agent comprising silver metal, a silver-containing compound, copper metal, a copper-containing compound, or a mixture of any of these.