Writing gel ink
The present disclosure relates to pens comprising a non-aqueous writing ink comprising a solvent, a coloring agent, a resin, a gelling agent, and a homo or copolymer of vinylpyrrolidone, wherein the gelling agent is a mixture of silica particles and of a fatty acid amide wax, and wherein the homo or copolymer of vinylpyrrolidone is present in amounts of between about 0.05 and about 0.6 wt.-%, relative to the total weight of the ink.
1 . A writing instrument, comprising:
a non-aqueous writing ink, comprising:
a solvent;
a gelling agent;
a coloring agent; and
a polymeric rheology agent comprising a homopolymer of vinylpyrrolidone, a copolymer of vinylpyrrolidone, or a mixture thereof, wherein the polymeric rheology agent is present in amounts of between 0.05 wt.-% and 0.3 wt.-%, relative to a total weight of the ink;
wherein the gelling agent comprises water-insoluble cellulose nanofibers.
2 . The writing instrument of claim 1 , wherein the polymeric rheology agent is a polyvinylpyrrolidone.
3 . The writing instrument of claim 1 , wherein the polymeric rheology agent has a weight-average molecular weight of above 200 kDa.
4 . The writing instrument of claim 1 , wherein the polymeric rheology agent is present in amounts of between 0.06 wt.-% and 0.25 wt.-%, relative to the total weight of the ink.
5 . The writing instrument of claim 1 , wherein the water-insoluble cellulose nanofibers are present in amounts of between 0.02 wt.-% and 0.5 wt.-%, relative to the total weight of the ink.
6 . The writing instrument of claim 1 , wherein the water-insoluble cellulose nanofibers are present in amounts of 0.05 wt.-% and 0.25 wt.-% relative to the total weight of the ink.
7 . The writing instrument of claim 1 , wherein the water-insoluble cellulose nanofibers comprise fibers having a diameter of less than 1000 nm and/or wherein the water-insoluble cellulose nanofibers comprise fibers having a diameter of more than 10 nm.
8 . The writing instrument of claim 1 , wherein the water-insoluble cellulose nanofibers comprise fibers having an aspect ratio of at least 5; and/or wherein the water-insoluble cellulose nanofibers comprise fibers having a length of at least 3 μm.
9 . The writing instrument of claim 1 , wherein the water-insoluble cellulose nanofibers comprise fibers which form a network.
10 . The writing instrument of claim 1 , wherein the water-insoluble cellulose nanofibers does not comprise 2,2,6,6-tetramethylpiperidine-1-oxyl radical-(TEMPO)-mediated or otherwise oxidized cellulose and does not comprise cellulose derivatives functionalized with an ether moiety.
11 . The writing instrument of claim 1 , wherein a relative weight ratio of the polymeric rheology agent to the water-insoluble cellulose nanofibers is between 6:1 to 1:6.
12 . The writing instrument of claim 1 , wherein the non-aqueous writing ink further comprises a viscosity-imparting agent.
13 . The writing instrument of claim 12 , wherein the viscosity-imparting agent is a resin selected from the group consisting of polyester resins, polyurethane resins, ketone resins, ketone-formaldehyde resins, ether resins, vinyl resins, polyvinyl alcohols, acrylic resins, styrene-acrylic resins, styrene-maleic acid copolymer resins, rosin-maleic acid copolymer resins, phenol resins, cellulosic resins, amid resins, alkyd resins, rosin modified resins, rosin modified phenol resins, xylene resins, polyacetal resins, terpene resins, phenoxy resins, and a mixture thereof; and/or wherein the viscosity-imparting agent is present in an amount of between 3 wt.-% and 30 wt.-%, 30% relative to the total weight of the ink.
14 . The writing instrument of claim 1 , wherein the non-aqueous writing ink further comprises silica particles.
15 . The writing instrument of claim 1 , wherein the solvent is selected from the group consisting of glycol ethers, alcohols, and a mixture thereof.
16 . The writing instrument of claim 1 , wherein the coloring agent is a dye.
17 . The writing instrument of claim 1 , wherein the non-aqueous writing ink further comprises one or more additives.
18 . The writing instrument of claim 1 , further comprising a ball-point at a writing tip, wherein the ball-point has a size of 0.7 mm.
19 . A non-aqueous writing ink, comprising:
a solvent;
a gelling agent;
a coloring agent; and
a polymeric rheology agent comprising a homopolymer of vinylpyrrolidone, a copolymer of vinylpyrrolidone, or a mixture thereof, wherein the polymeric rheology agent is present in amounts of between 0.05 wt.-% and 0.3 wt.-% relative to a total weight of the ink;
wherein the gelling agent comprises water-insoluble non-oxidized cellulose nanofibers.
20 . A process of preparing the non-aqueous writing ink according to claim 19 , wherein the non-aqueous writing ink is prepared by:
a) providing a first homogeneous premix comprising the water-insoluble cellulose nanofibers and at least a part of the solvent; and
b) combining the first premix with a remainder of the components of the non-aqueous writing ink.