Writing gel ink

Abstract

The present disclosure relates to a pen containing a non-aqueous writing ink comprising a solvent, a colorant, a resin, a gelling agent, and a homo- or copolymer of vinylpyrrolidone and / or a polyvinyl alcohol acetalized with an aldehyde containing 1 to about 6 carbon atoms, wherein the gelling agent is a mixture of silica particles and a fatty acid amide wax, the homo- or copolymer of vinylpyrrolidone, if present, is present in an amount of about 0.05 to about 0.6% by weight, based on the total weight of the ink, and the polyvinyl alcohol acetalized with an aldehyde containing 1 to about 6 carbon atoms, if present, is present in an amount of about 0.05 to about 1.0% by weight, based on the total weight of the ink.

Description

Technical Field

[0001] The present disclosure relates to writing instruments, particularly pens such as ballpoint pens, and writing inks for use within such writing instruments.

Background Art

[0002] Conventionally, ballpoint pen inks have been Newtonian high-viscosity solvent-based inks. Due to the use of low-volatility glycol solvents, ballpoint pen inks are very stable during storage because the ink does not dry. Thus, such inks can be used in pens without tip protection. While such glycol solvent systems are desirable, they also typically have high shear viscosities. Again, high shear viscosity is not an undesirable property per se as it helps to avoid static leakage. Static leakage corresponds to the formation of ink droplets at the tip, particularly when the pen is stored tip-down in hot and humid conditions. In a Newtonian system, high shear viscosity is also correlated with static viscosity and thus helps to reduce the problem of sedimentation of pigments and other solids that can clog the pen tip. However, at high shear viscosities, the writing experience is not as smooth as consumers would like. It has proven very difficult to balance these properties.

[0003] To address these problems, formulators have turned to gel inks. Gel inks have a pseudoplastic rheological profile. Generally, gel inks are water-based. They are a good compromise between low static leakage, smoothness, and particle stabilization. However, they still suffer from some drawbacks.

[0004] Water is a lightweight and volatile solvent. When stored without tip protection (cap or hot melt), the ink within the tip can dry and clog the tip. Furthermore, it has been found that the cap-off time of gel ink pens is much less than that of glycol-based ballpoint pens.

[0005] Despite using a corrosion inhibitor, the aqueous ink remains a corrosive fluid. Therefore, it is impossible to use a tip made of copper, and it is essential to use a tip made of stainless steel, which is a very expensive material and difficult to manufacture due to the hardness of the material.

[0006] Furthermore, since water has poor lubricity, it is also essential to use the tip with a strong flow rate. In the case of a typical pen, it has been found that the flow rate of a ballpoint pen with aqueous ink cannot be reduced to less than about 300 mg / 200 m. This is disadvantageous compared to glycol-based ink with a flow rate of about 35 mg / 200 m. As a result, the writing distance (i.e., the total length of writing with the pen) of an aqueous ink pen is much less than that of a glycol-based ink pen.

[0007] Glycol-based inks for ballpoint pens, or more generally, solvent-based inks, have also been described in the prior art. In particular, JP3078172 and JPH07-196972 describe the use of fatty acid amide wax in an oil-based ink composition as a thixotropic agent. However, the use of only fatty amide wax is not sufficient to avoid static leakage of the ink. In WO2019 / 122017 A1, this technical problem is addressed by using a combination of fatty acid amide wax and silica particles used as a gelling agent.

[0008] However, especially when trying to balance the rheological properties of the ink to achieve both excellent writing performance and avoid ink leakage from the pen in both dynamic situations (e.g., after writing or after an impact event such as the pen dropping) and static situations (e.g., when storing the pen on a shelf or maintaining the pen in a state close to the human body in a pocket under heat and humidity), there is still room for further improvement in solvent-based inks for ink pens. In particular, the problem of gooping, i.e., unwanted leakage from the pen tip immediately after writing, remains a problem. Summary of the Invention

[0009] In a first aspect, the present disclosure relates to a writing instrument. The writing instrument can be a pen, particularly a ballpoint pen. The writing instrument can contain a non-aqueous writing ink. The non-aqueous writing ink can contain a solvent, a colorant, a resin, a gelling agent, and a homopolymer or copolymer of vinyl pyrrolidone, and / or polyvinyl alcohol acetalized with an aldehyde containing from 1 to about 6 carbon atoms. The gelling agent can contain a mixture of silica particles and a fatty acid amide wax. When present, the homopolymer or copolymer of vinyl pyrrolidone can be present in an amount of 0.05 to 0.6% by weight based on the total weight of the ink. When present, polyvinyl alcohol acetalized with an aldehyde containing from 1 to about 6 carbon atoms can be present in an amount of about 0.05 to about 1.0% by weight based on the total weight of the ink.

[0010] In some embodiments, the homopolymer or copolymer of vinyl pyrrolidone can be polyvinyl pyrrolidone.

[0011] In some embodiments, the homopolymer or copolymer of vinyl pyrrolidone can be polyvinyl pyrrolidone having a weight average molecular weight of greater than about 200 kDa, specifically from about 400 to about 2300 kDa, more specifically from about 450 to about 2000 kDa, particularly from about 600 to about 1900 kDa.

[0012] In some embodiments, the weight of vinyl pyrrolidone, particularly the homopolymer or copolymer of polyvinyl pyrrolidone, can be less than the weight of the mixture of silica particles and fatty acid amide wax.

[0013] In some embodiments, the polyvinyl alcohol is acetalized with an aldehyde containing from 1 to about 6 carbon atoms.

[0014] In some embodiments, the polyvinyl alcohol is acetalized with an aldehyde containing 2 or 3, 2 to 4, or 2 to 5 carbon atoms.

[0015] In some embodiments, it may be particularly advantageous for the polyvinyl alcohol acetalized with an aldehyde containing from 1 to about 6 carbon atoms to be polyvinyl butyral.

[0016] In some embodiments, the polyvinyl alcohol acetalized with an aldehyde containing from 1 to about 6 carbon atoms may be polyvinyl butyral having a weight average molecular weight of greater than about 200 kDa, specifically from about 400 to about 2300 kDa, more specifically from about 450 to about 2000 kDa, and particularly from about 600 to about 1900 kDa.

[0017] In some embodiments, the weight of the polyvinyl alcohol acetalized with an aldehyde containing from 1 to about 6 carbon atoms, particularly polyvinyl butyral, may be less than the weight of the mixture of silica particles and fatty acid amide.

[0018] In some embodiments, the silica particles may include hydrophilic silica particles. In some embodiments, the hydrophilic silica particles may be present in an amount of from about 0.10 to about 0.60% by weight based on the total weight of the ink.

[0019] In some embodiments, the fatty acid amide wax may include N,N'-ethylene-bis-fatty acid amide. In some embodiments, it may be advantageous for the fatty acid amide wax to include octadecanamide of the following formula (I)

Chemical formula

[0020] In some embodiments, the gelling agent may be present in an amount of from about 0.1 to about 1.2% by weight, more specifically from about 0.15 to about 0.60% by weight based on the total weight of the ink.

[0021] In some embodiments, the solvent can be selected from the group consisting of glycol ethers, alcohols, and mixtures thereof. Advantageously, the solvent can be selected from polyethylene glycol ethers, polypropylene glycol ethers, phenoxyethanol, 1 - phenoxy - 2 - propanol, or mixtures thereof.

[0022] In some embodiments, the solvent can be present in an amount of about 35% to about 80% by weight, based on the total weight of the ink. Advantageously, in some embodiments, the solvent can be present in an amount of about 45% to about 75% by weight, based on the total weight of the ink.

[0023] In some embodiments, the colorant can be a dye, particularly a dye selected from the group consisting of azo dyes, triarylmethane dyes, phthalocyanine derivative dyes, xanthene dyes, and mixtures thereof.

[0024] In some embodiments, the colorant can be present in an amount of about 5% to about 30% by weight, particularly about 7% to about 28% by weight, based on the total weight of the ink.

[0025] In some embodiments, the non - aqueous writing ink can further include one or more additives. In some embodiments, the additive can be an additional gelling agent. Advantageously, in some embodiments, the non - aqueous writing ink can further include one or more additives selected from the group consisting of thickeners, clear - down agents, tackifiers, lubricants, dispersants, and mixtures thereof.

[0026] In some embodiments, the non - aqueous writing ink can include about 0.1% to about 0.6% by weight of polyvinylpyrrolidone having a weight - average molecular weight of about 450 to about 2000 kDa, about 0.15% to about 0.60% by weight of fatty acid amide wax, and about 0.15% to about 0.60% by weight of hydrophilic silica, in amounts based on the total weight of the ink.

[0027] In some embodiments, the non-aqueous writing ink may include, in an amount relative to the total weight of the ink, about 0.1 to about 1.0 wt% of polyvinyl butyral having a weight average molecular weight of about 450 to about 2000 kDa, about 0.15 to about 0.60 wt% of fatty acid amide wax, and about 0.15 to about 0.60 wt% of hydrophilic silica.

[0028] In some embodiments, the non-aqueous writing ink may include the aforementioned polyvinyl pyrrolidone. In some embodiments, the non-aqueous writing ink may include the aforementioned polyvinyl alcohol, particularly polyvinyl butyral. In some embodiments, the non-aqueous writing ink may include both.

[0029] In some embodiments, the non-aqueous writing ink may include a resin selected from polyester resins, polyurethane resins, ketone resins, ether resins, and mixtures thereof. It may be advantageous for the resin to be a ketone resin. Additionally or alternatively, the resin may be present in an amount of about 3 to about 30%, specifically about 3 to about 25%, particularly about 5 to about 20% based on the total weight of the ink. Alternatively, the ink may include about 55 to about 75 wt% of 1-phenoxy-2-propanol. Also, the fatty acid amide wax of the non-aqueous writing ink is N,N'-ethylene-bis-fatty acid amide, particularly the octadecanamide of the following formula (I)

Chemical formula

[0030] In some embodiments, the ink may have a loss factor at rest tanδ of about 3 to about 15, more specifically about 4 to about 12, particularly about 5 to about 10. Additionally or alternatively, the ink may have a loss factor after shear of about 8 to about 60, more specifically about 11 to about 50, particularly about 15 to about 40.

[0031] In some embodiments, the non-aqueous writing ink may consist of the following components in amounts based on the total weight of the ink: about 55 to about 75% by weight of a solvent selected from polyethylene glycol ether, polypropylene glycol ether, phenoxyethanol, 1-phenoxy-2-propanol, or a mixture thereof, about 10 to about 30% by weight of a colorant, about 0.10 to about 0.60% by weight of polyvinylpyrrolidone having a weight average molecular weight of about 600 to about 1900 kDa, about 0.15 to about 0.60% by weight of a fatty acid amide wax, about 0.15 to about 0.60% by weight of hydrophilic silica, and the remaining components selected from resins and additives.

[0032] In some embodiments, the non-aqueous writing ink may consist of the following components in amounts based on the total weight of the ink: about 55 to about 75% by weight of a solvent selected from polyethylene glycol ether, polypropylene glycol ether, phenoxyethanol, 1-phenoxy-2-propanol, or a mixture thereof, about 10 to about 30% by weight of a colorant, about 0.10 to about 1.0% by weight of polyvinyl butyral having a weight average molecular weight of about 600 to about 1900 kDa, about 0.15 to about 0.60% by weight of a fatty acid amide wax, about 0.15 to about 0.60% by weight of hydrophilic silica, and the remaining components selected from resins and additives.

[0033] In some embodiments, the non-aqueous writing ink may consist of the following components in amounts based on the total weight of the ink: about 55 to about 75% by weight of a solvent selected from polyethylene glycol ether, polypropylene glycol ether, phenoxyethanol, 1-phenoxy-2-propanol, or a mixture thereof, about 10 to about 30% by weight of a colorant, about 0.10 to about 0.60% by weight of polyvinylpyrrolidone having a weight average molecular weight of about 600 to about 1900 kDa and / or polyvinyl butyral having a weight average molecular weight of about 600 to about 1900 kDa, about 0.15 to about 0.60% by weight of a fatty acid amide wax, about 0.15 to about 0.60% by weight of hydrophilic silica, and the remaining components selected from resins and additives.

[0034] In some embodiments, the non-aqueous writing ink comprises, in amounts based on the total weight of the ink, the following components: about 55 to about 75% by weight of 1-phenoxy-2-propanol, about 10 to about 30% by weight of a colorant, about 0.10 to about 0.60% by weight of polyvinylpyrrolidone having a weight average molecular weight of about 600 to about 1900 kDa, N,N'-ethylene-bis-fatty acid amide, particularly, the following formula (I)

Chemical formula

[0035] In some embodiments, the non-aqueous writing ink comprises, in amounts based on the total weight of the ink, the following components: about 55 to about 75% by weight of 1-phenoxy-2-propanol, about 10 to about 30% by weight of a colorant, about 0.10 to about 1.0% by weight of polyvinyl butyral having a weight average molecular weight of about 600 to about 1900 kDa, N,N'-ethylene-bis-fatty acid amide, particularly, the following formula (I)

Chemical formula

[0036] In some embodiments, the non-aqueous writing ink comprises the following components in amounts based on the total weight of the ink: about 55 to about 75% by weight of 1-phenoxy-2-propanol, about 10 to about 30% by weight of a colorant, about 0.10 to about 0.60% by weight of polyvinylpyrrolidone having a weight average molecular weight of about 600 to about 1900 kDa, and / or polyvinyl butyral having a weight average molecular weight of about 600 to about 1900 kDa, N,N'-ethylene-bis-fatty acid amide, particularly, the following formula (I) [Chemical formula] about 0.15 to about 0.60% by weight of a fatty acid amide wax containing N,N'-ethylene-bis-fatty acid amide having the following formula (I), about 0.15 to about 0.60% by weight of hydrophilic silica, about 5 to about 15% by weight of a resin, additives, particularly, the remaining components which are the additives defined above, and may comprise or consist of these.

[0037] In a second aspect, the present disclosure relates to a non-aqueous writing ink comprising a solvent, a colorant, a resin, a gelling agent, and a homopolymer or copolymer of vinylpyrrolidone, the gelling agent being a mixture of silica particles and fatty acid amide wax, and the homopolymer or copolymer of vinylpyrrolidone being present in an amount of about 0.05 to about 0.6% by weight based on the total weight of the ink.

[0038] In relation to the second aspect, the present disclosure relates to a non-aqueous writing ink comprising a solvent, a colorant, a resin, a gelling agent, and polyvinyl alcohol acetalized with an aldehyde containing 1 to about 6 carbon atoms, the gelling agent being a mixture of silica particles and fatty acid amide wax, and polyvinyl alcohol acetalized with an aldehyde containing 1 to about 6 carbon atoms being present in an amount of about 0.05 to about 1.0% by weight based on the total weight of the ink.

[0039] The embodiments described for the first aspect of the present disclosure above can be combined with the second aspect described above of the present disclosure equally.

[0040] In a third aspect, the present disclosure relates to a process for preparing a writing instrument according to the first aspect of the present disclosure or a non-aqueous writing ink according to the second aspect of the present disclosure. The non-aqueous writing ink can be prepared by the following steps: a) forming a first preliminary mixture containing silica particles in a solvent. The temperature in this step can be about 30 to about 70 °C. The first preliminary mixture can be mixed at a shear rate of about 20 to about 25 m / sec. b) combining the first preliminary mixture with the remaining components of the non-aqueous writing ink.

[0041] In relation to a third aspect, the present disclosure relates to a process for preparing a writing instrument according to the first aspect of the present disclosure or a non-aqueous writing ink according to the second aspect of the present disclosure. The non-aqueous writing ink can be prepared by the following steps: a) forming a first preliminary mixture containing silica particles in a solvent. The temperature in this step can be about 30 to about 70 °C. The first preliminary mixture can be mixed at a shear rate of about 20 to about 25 m / sec. b) combining the first preliminary mixture with the remaining components of the non-aqueous writing ink.

[0042] In some embodiments, the non-aqueous writing ink can be prepared by the following steps: a) forming a first preliminary mixture containing silica particles in a solvent. The temperature in this step can be about 30 to about 70 °C. The first preliminary mixture can be mixed at a shear rate of about 20 to about 25 m / sec. b) forming a second preliminary mixture containing fatty acid amide wax in a solvent. The temperature in this step can be about 30 to about 70 °C. The second preliminary mixture can be mixed at a shear rate of about 20 to about 25 m / sec. c) combining the first and second preliminary mixtures with the remaining components of the non-aqueous writing ink.

[0043] The embodiments described for the above first aspect of the present disclosure can be combined equivalently with the aforementioned third aspect of the present disclosure.

Brief Description of the Drawings

[0044]

Figure 1

Best Mode for Carrying Out the Invention

[0045] Hereinafter, the present disclosure will be described in detail. Terms or words used in the description and claims of the present disclosure should not be construed restrictively as having only the meaning of a common language or dictionary, but should be construed as having their ordinary technical meaning as established in the relevant technical field, unless otherwise specifically defined in the following description. The detailed description refers to specific embodiments for better illustrating the present disclosure, but it should be understood that the presented disclosure is not limited to these specific embodiments.

[0046] In a first aspect, the present disclosure relates to a writing instrument. The writing instrument can be a pen, particularly a ballpoint pen. The writing instrument can contain non-aqueous writing ink. In this context, non-aqueous means that the ink does not contain water as a solvent for the dye / pigment and / or can be substantially free (e.g., containing less than about 2% by weight relative to the total weight of the ink) or does not contain water.

[0047] The non-aqueous writing ink can contain a solvent, a colorant, a resin, a gelling agent, and a homopolymer or copolymer of vinyl pyrrolidone, and / or polyvinyl alcohol acetalized with an aldehyde containing 1 to about 6 carbon atoms. The gelling agent can contain a mixture of silica particles and fatty acid amide wax. It should be understood that the presence of additional gelling agents is not excluded and one or more additional gelling agents can optionally be added to the ink.

[0048] The homo- or co-polymer of vinylpyrrolidone may be present in an amount of about 0.05% to about 0.6% by weight, more specifically about 0.08% to about 0.5% by weight, even more specifically about 0.1% to about 0.4% by weight, and particularly about 0.10% to about 0.35% by weight, based on the total weight of the ink. Surprisingly, for the aforementioned non-aqueous writing ink, the addition of a selected amount of the homo- or co-polymer of vinylpyrrolidone, particularly the addition of polyvinylpyrrolidone having a weight average molecular weight of greater than about 200 kDa, specifically about 400 to about 2300 kDa, more specifically about 450 to about 2000 kDa, and particularly about 600 to about 1900 kDa, has been found to provide very well-balanced writing and storage performance. This effect will be described in more detail in the Examples section below. Without wishing to be bound by theory, it is assumed that the fatty acid amide wax creates a gelling network with the solvent mediated by hydrogen bonds. Again, without wishing to be bound by theory, the ability of the homo- or co-polymer of vinylpyrrolidone to allow hydrogen bonds from its gelling network without contributing hydrogen bonds to the network itself is thought to introduce "elasticity" into the shear-independent ink. This effect is thought to provide the aforementioned very well-balanced writing and storage performance. Notably, this effect depends on the concentration of the homo- or co-polymer of vinylpyrrolidone having an amount greater than 0.6% by weight based on the total weight of the ink and has been found to adversely affect the writing performance.

[0049] In some embodiments, the homo- or co-polymer of vinylpyrrolidone may have a weight average molecular weight of greater than about 200 kDa, specifically about �00 to about 2300 kDa, more specifically about 450 to about 2000 kDa, and particularly about 600 to about 1900 kDa.

[0050] In some embodiments, the homo- or co-polymer of vinyl pyrrolidone can be polyvinyl pyrrolidone. It can be advantageous for the polyvinyl pyrrolidone to have a weight average molecular weight of greater than about 200 kDa, specifically, from about 400 to about 2300 kDa, more specifically, from about 450 to about 2000 kDa, and particularly, from about 600 to about 1900 kDa.

[0051] Polyvinyl alcohol acetalized with an aldehyde containing from 1 to about 6 carbon atoms can be present in an amount of from about 0.05 to about 1.0 wt%, more specifically, from about 0.08 to about 0.8 wt%, even more specifically, from about 0.1 wt% to about 0.6 wt%, and particularly, from about 0.10 wt% to about 0.45 wt% based on the total weight of the ink. Surprisingly, for the aforementioned non-aqueous writing ink, the addition of a selected polyvinyl alcohol acetalized with an aldehyde containing from 1 to about 6 carbon atoms, particularly the addition of polyvinyl butyral having a weight average molecular weight of greater than about 200 kDa, specifically, from about 400 to about 2300 kDa, more specifically, from about 450 to about 2000 kDa, and particularly, from about 600 to about 1900 kDa, has been found to provide very well-balanced writing and storage performance. Without wishing to be bound by theory, it is again hypothesized that the fatty acid amide wax creates a gelling network with the solvent mediated by hydrogen bonds. Again, without wishing to be bound by theory, the ability of polyvinyl alcohol acetalized with an aldehyde containing from 1 to about 6 carbon atoms, which while accepting hydrogen bonds from the gelling network, has a reduced ability to contribute hydrogen bonds to the network itself (due to the acetalization of the hydroxyl groups), is thought to introduce "elasticity" into the shear-independent ink. This effect is thought to provide the aforementioned very well-balanced writing and storage performance.

[0052] In some embodiments, the polyvinyl alcohol acetalized with an aldehyde containing from 1 to about 6 carbon atoms can have a weight average molecular weight of greater than about 200 kDa, specifically, from about 400 to about 2300 kDa, more specifically, from about 450 to about 2000 kDa, particularly from about 600 to about 1900 kDa.

[0053] In some embodiments, the polyvinyl alcohol acetalized with an aldehyde containing from 1 to about 6 carbon atoms can be polyvinyl butyral. It can be advantageous for the polyvinyl butyral to have a weight average molecular weight of greater than about 200 kDa, specifically, from about 400 to about 2300 kDa, more specifically, from about 450 to about 2000 kDa, particularly from about 600 to about 1900 kDa.

[0054] In some embodiments, it can be advantageous for the polyvinyl alcohol acetalized with an aldehyde containing from 1 to about 6 carbon atoms, particularly polyvinyl butyral, to be used in combination with a homo- or co-polymer of vinyl pyrrolidone, particularly vinyl pyrrolidone. In such embodiments, these two polymers can be present jointly in an amount of from about 0.05 to about 1.0% by weight, more specifically from about 0.08 to about 0.8% by weight, even more specifically from about 0.1% by weight to about 0.6% by weight, particularly from about 0.10% by weight to about 0.45% by weight, based on the total weight of the ink. In such embodiments, it can be advantageous for the homo- or co-polymer of vinyl pyrrolidone, particularly vinyl pyrrolidone, to have a weight average molecular weight of greater than about 200 kDa, specifically, from about 400 to about 2300 kDa, more specifically, from about 450 to about 2000 kDa, particularly from about 600 to about 1900 kDa. As shown, the gelling agent can include a mixture of silica particles and fatty acid amide wax. The term "mixture" is not particularly limited and is intended to refer to any combination containing silica particles and fatty acid amide wax. In some embodiments, it can be advantageous to pre-mix the silica particles and the fatty acid amide wax. A suitable process for doing this will be described in more detail below.

[0055] In some embodiments, the silica particles may include silica particles. It may be advantageous for the silica particles to be hydrophilic silica particles. It may be advantageous for the silica particles to be hydrophilic fumed silica particles, such as fumed silica particles sold under the trade name AEROSIL® 200 by Evonik.

[0056] In some embodiments, the non-aqueous writing ink may include dispersed silica particles or silica-based gel-like particles, and the average particle size is less than about 1 μm, more specifically less than about 0.9 μm, particularly less than about 0.8 μm, using dynamic light scattering (DLS) such as Malvern Zetasizer ZS.

[0057] The use of fatty acid amide waxes is well established in the art, inter alia, as rheology modifiers. Suitable fatty acid residues may include aliphatic carboxylic acids having more than about 6 carbon atoms, particularly from about 6 to about 24 carbon atoms, or from about 6 to about 18 carbon atoms. The aliphatic carboxylic acid may optionally be substituted, particularly with a hydroxyl group. Examples of suitable fatty acid residues include residues derived from caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, hydroxystearic acid, arachidic acid, and behenic acid.

[0058] In some embodiments, the fatty acid amide wax is a fatty acid diamide wax. The fatty acid diamide wax may include a fatty acid diamide containing two fatty acid residues of about 6 or more carbon atoms, particularly about 6 to about 24 carbon atoms, or about 6 to about 18 carbon atoms, which may optionally be substituted, particularly with hydroxyl groups. It may be advantageous for the fatty acid diamide wax to include an N,N'-alkylene moiety having 1 to about 12 carbon atoms, particularly 1 to about 6 carbon atoms, particularly about 2 to about 4 carbon atoms. It may be particularly advantageous for the fatty acid diamide wax to include N,N'-ethylene-bis-fatty acid amide, particularly where the two fatty acid residues each independently include about 6 or more carbon atoms, particularly about 6 to about 24 carbon atoms, or about 6 to about 18 carbon atoms. Each of the fatty acid residues may further and independently be substituted, particularly with hydroxyl groups.

[0059] In some embodiments, it may be advantageous for the fatty acid amide wax to include 12-hydroxy-N-[2-[(1-oxooctyl)amino]ethyl]octadecanamide, N,N'-1,2-ethylenebis(12-hydroxy-octadecanamide), N,N'-1,2-ethylenebis(12-hydroxyoctadecanamide), N,N'-ethylenebis(12-hydroxystearamide), N,N'-ethylenebis(caprylamide), or mixtures thereof.

[0060] In some embodiments, the fatty acid amide wax is of the following formula (I)

Chemical formula

[0061] In some embodiments, the gelling agent may be present in an amount of about 0.1 to about 1.2 wt%, more specifically about 0.15 to about 0.60 wt%, based on the total weight of the ink.

[0062] In some embodiments, the hydrophilic silica particles may be present in an amount of from about 0.10 to about 0.60 weight percent, based on the total weight of the ink.

[0063] In some embodiments, the fatty acid amide wax may be present in an amount of from about 0.10 to about 0.60 weight percent, based on the total weight of the ink.

[0064] In some embodiments, the weight of vinyl pyrrolidone, particularly a homo- or co-polymer of polyvinyl pyrrolidone, may be less than the weight of the mixture of silica particles and fatty acid amide wax.

[0065] In some embodiments, the weight of polyvinyl alcohol acetalized with an aldehyde containing from 1 to about 6 carbon atoms, particularly polyvinyl butyral, may be less than the weight of the mixture of silica particles and fatty acid amide.

[0066] The non-aqueous ink for writing may contain a solvent. The term "solvent" is not intended to be particularly limited and includes, inter alia, a medium for dispersing or suspending solid components such as pigments. In some embodiments, the solvent may be selected from the group consisting of glycol ethers, alcohols, and mixtures thereof. It may be advantageous for the solvent to be selected from polyethylene glycol ether, polypropylene glycol ether, phenoxyethanol, 1-phenoxy-2-propanol, or mixtures thereof. In some embodiments, the alcohol is an alcohol having a high boiling point such as a boiling point above about 130°C, above about 150°C, or above about 200°C. In some embodiments, the alcohol may be selected from the group consisting of benzyl alcohol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, trimethylene glycol, glycerin, and mixtures thereof. It may be particularly advantageous for the alcohol to be benzyl alcohol. In another embodiment, the solvent may be a glycol ether having a high boiling point such as a boiling point above about 130°C, above about 150°C, or above about 200°C. The glycol ether may advantageously be selected from the group consisting of diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, phenoxyethanol, phenoxypropanol, and mixtures thereof. It may be particularly advantageous for the glycol ether to be selected from the group consisting of phenoxyethanol, 1-phenoxy-2-propanol, and mixtures thereof.

[0067] In some embodiments, the solvent may be present in an amount of about 35 to about 80% by weight, based on the total weight of the ink. In some embodiments, it may be advantageous for the solvent to be present in an amount of about 45 to about 75% by weight, based on the total weight of the ink.

[0068] In some embodiments, it may be advantageous for the ink to contain about 55 to about 75% by weight of 1-phenoxy-2-propanol.

[0069] In some embodiments, the colorant can be a dye, a pigment, or a mixture thereof, particularly a dye or pigment selected from the group consisting of azo dyes, triarylmethane dyes, phthalocyanine derivative dyes, xanthene dyes, and mixtures thereof. In some embodiments, the colorant can be a pigment.

[0070] Examples of dyes that can be used in the inks according to the present disclosure include the following. VARIFAST Black 3806 (C.I. Solvent Black 29), 3807 (trimethylbenzylammonium salt of C.I. Solvent Black 29), Spirit Black SB (C.I. Solvent Black 5), SPIRON Black GMH (C.I. Solvent Black 43), Solvent Black 46 (salt formation form of C.I. Basic Violet 3 and Acid Yellow 36), VARIFAST Red 1308 (salt formation form of C.I. Basic Red 1 dye and C.I. Acid Yellow 23 dye), Solvent Red 49, VARIFAST Yellow AUM (salt formation form of C.I. Basic Yellow 2 dye and C.I. Acid Yellow 42 dye), SPIRON Yellow C2 GH (organic acid salt of C.I. Basic Yellow 2), SPIRON Violet CRH (C.I. Solvent Violet 8-1), VARIFAST Violet 1701 (salt formation form of C.I. Basic Violet 1 and C.I. Acid Yellow 42 dye), SPIRON Red CGH (organic acid salt of C.I. Basic Red 1), SPIRON Pink BH (C.I. Solvent Red 82), Nigrosine Base EX (C.I. Solvent Black 7), Oil Blue 613 (C.I. Solvent Blue 5), and Neozapon Blue 808 (C.I. Solvent Blue 70).

[0071] In some embodiments, the colorant can be a dye and can be selected from salt-forming dyes such as Solvent Black 46 (salt-forming form of C.I. Basic Violet 3 and Acid Yellow 36), VARIFAST Red 1308 (salt-forming form of C.I. Basic Red 1 dye and C.I. Acid Yellow 23 dye), VARIFAST Yellow AUM (salt-forming form of C.I. Basic Yellow 2 dye and C.I. Acid Yellow 42 dye), VARIFAST Violet 1701 (salt-forming form of C.I. Basic Violet 1 and C.I. Acid Yellow 42 dye), and mixtures thereof.

[0072] Examples of pigments that can be used in the ink according to the present disclosure include organic, inorganic, and processed pigments. Therefore, the pigments can be, for example, inorganic pigments such as carbon black, ultramarine, and titanium dioxide pigments, azo pigments, phthalocyanine pigments, indigo pigments, thioindigo pigments, perylene pigments, quinacridone pigments, anthraquinone pigments, threne pigments, diketopyrrolopyrrole pigments, dioxazine pigments, perylene pigments, perinone pigments, and isoindolinone pigments, organic pigments, metal pigments such as aluminum powder or aluminum powder whose surface is treated with a colored resin, metallic luster pigments obtained by forming a metal vapor deposition film such as aluminum on a transparent or colored transparent film, metal pigments having a thickness of about 0.01 to about 0.1 μm obtained by peeling a metal vapor deposition film such as aluminum formed on a substrate such as a film, colloidal particles having an average particle diameter of about 5 to about 30 nm selected from gold, silver, platinum, and copper, fluorescent pigments, phosphorescent pigments, naturally occurring mica, synthetic mica, glass flakes, alumina, and pearl pigments obtained by coating the surface of a core, which is a transparent film, with a metal oxide such as titanium dioxide.

[0073] In some embodiments, the colorant can be present in an amount of about 5 to about 30% by weight, particularly about 7 to about 28% by weight, based on the total weight of the ink.

[0074] In some embodiments, the non-aqueous writing ink may further include one or more additives. In some embodiments, the additive may be an additional gelling agent. In some embodiments, it may be advantageous for the non-aqueous writing ink to further include one or more additives. In some embodiments, the additive may be selected from the group consisting of thickeners, clear drain agents, tackifiers, lubricants, dispersants, and mixtures thereof.

[0075] In some embodiments, the non-aqueous writing ink may include from about 0.1 to about 0.6 wt% of polyvinylpyrrolidone having a weight average molecular weight of about 450 to about 2000 kDa, from about 0.15 to about 0.60 wt% of fatty acid amide wax, and from about 0.15 to about 0.60 wt% of hydrophilic silica, in amounts based on the total weight of the ink.

[0076] In some embodiments, the non-aqueous writing ink may include from about 0.1 to about 1.0 wt% of polyvinyl butyral having a weight average molecular weight of about 450 to about 2000 kDa, from about 0.15 to about 0.60 wt% of fatty acid amide wax, and from about 0.15 to about 0.60 wt% of hydrophilic silica, in amounts based on the total weight of the ink.

[0077] In some embodiments, the non-aqueous writing ink may include from about 0.1 to about 0.6 wt% of polyvinylpyrrolidone having a weight average molecular weight of about 450 to about 2000 kDa, polyvinyl butyral having a weight average molecular weight of about 450 to about 2000 kDa, from about 0.15 to about 0.60 wt% of fatty acid amide wax, and from about 0.15 to about 0.60 wt% of hydrophilic silica, in amounts based on the total weight of the ink.

[0078] Non-aqueous ink for writing may contain a resin. The resin may impart viscosity to the ink and / or act as a binder. It may be a natural resin or a synthetic resin. The resin may include polyester resin, polyurethane resin, ketone resins such as ketone-formaldehyde resins like acetophenone-formaldehyde modified resin, ether resin, vinyl chloride copolymer, polyvinyl butyral, vinyl acetate, vinyl acetate copolymer, or vinyl resins such as polyvinyl alcohol resin, acrylic resin, styrene-acrylic resin, styrene-maleic acid copolymer resin, rosin-maleic acid copolymer resin, phenol resin, cellulose resin, amide resin, alkyd resin, rosin-modified resin, rosin-modified phenol resin, xylene resin, polyacetal resin, terpene resin, phenoxy resin, or a mixture thereof. In some embodiments, a resin selected from polyester resin, polyurethane resin, ketone resin, ether resin, and mixtures thereof may be advantageous. It may be particularly advantageous for the resin to be a ketone resin.

[0079] In some embodiments, the resin may be present in an amount of about 3% to about 30%, specifically about 3% to about 25%, particularly about 5% to about 20% based on the total weight of the ink.

[0080] In some embodiments, the non-aqueous ink for writing may contain or consist of the following components in amounts based on the total weight of the ink: about 55% to about 75% by weight of a solvent selected from polyethylene glycol ether, polypropylene glycol ether, phenoxyethanol, 1-phenoxy-2-propanol, or a mixture thereof, about 10% to about 30% by weight of a colorant, about 0.10% to about 0.60% by weight of polyvinylpyrrolidone having a weight average molecular weight of about 600 to about 1900 kDa, about 0.15% to about 0.60% by weight of fatty acid amide wax, about 0.15% to about 0.60% by weight of hydrophilic silica, and the remaining components selected from resins and additives.

[0081] In some embodiments, the non-aqueous writing ink may include, or consist of, the following components in amounts based on the total weight of the ink: about 55 to about 75% by weight of a solvent selected from polyethylene glycol ether, polypropylene glycol ether, phenoxyethanol, 1-phenoxy-2-propanol, or a mixture thereof; about 10 to about 30% by weight of a colorant; about 0.10 to about 0.60% by weight of polyvinyl butyral having a weight average molecular weight of about 600 to about 1900 kDa; about 0.15 to about 0.60% by weight of a fatty acid amide wax; about 0.15 to about 0.60% by weight of hydrophilic silica; and the remaining components selected from resins and additives.

[0082] In some embodiments, the non-aqueous writing ink may include, or consist of, the following components in amounts based on the total weight of the ink: about 55 to about 75% by weight of a solvent selected from polyethylene glycol ether, polypropylene glycol ether, phenoxyethanol, 1-phenoxy-2-propanol, or a mixture thereof; about 10 to about 30% by weight of a colorant; about 0.10 to about 0.60% by weight of polyvinyl pyrrolidone having a weight average molecular weight of about 600 to about 1900 kDa and polyvinyl butyral having a weight average molecular weight of about 600 to about 1900 kDa; about 0.15 to about 0.60% by weight of a fatty acid amide wax; about 0.15 to about 0.60% by weight of hydrophilic silica; and the remaining components selected from resins and additives.

[0083] In some embodiments, the non-aqueous writing ink may include, or consist of, the following components in amounts based on the total weight of the ink: about 55 to about 75% by weight of 1-phenoxy-2-propanol; about 10 to about 30% by weight of a colorant; about 0.10 to about 0.60% by weight of polyvinyl pyrrolidone having a weight average molecular weight of about 600 to about 1900 kDa; and about 0.15 to about 0.60% by weight of a fatty acid amide wax containing N,N'-ethylene-bis-fatty acid amide, particularly, N,N'-ethylene-bis-fatty acid amide having the following formula (I)

Chemical formula

[0084] In some embodiments, the non-aqueous writing ink may have a static viscosity of about 30,000 cps to about 150,000 cps, more specifically about 40,000 cps to about 120,000 cps, particularly about 50,000 cps to about 100,000 cps at about 20 °C. The static viscosity is measured at about 20 °C using a cone and plate rheometer such as a Malvern Kinexus with a cone of about 40 mm and an angle of about 4° at a shear rate of 0.01 second -1 .

[0085] In some embodiments, the non-aqueous writing ink may have a viscosity of about 1200 cps to about 10,000 cps, more specifically about 1300 cps to about 5000 cps, particularly about 1500 cps to about 4000 cps under shear at about 20 °C and about 100 seconds -1 . -1 The viscosity under shear can be measured at about 20 °C using a cone and plate rheometer such as a Malvern Kinexus with a cone of about 40 mm and an angle of about 4° at a shear rate of 100 seconds

[0086] In some embodiments, the non-aqueous writing ink may have a static loss factor tanδ of about 3 to about 15, more specifically about 4 to about 12, particularly about 5 to about 10. The static loss factor tanδ can be measured at about 20 °C using a cone and plate rheometer such as a Malvern Kinexus with a cone of about 40 mm and an angle of about 4° in a vibration measurement (frequency = about 1 Hz, shear about 20 Pa).

[0087] In some embodiments, the non-aqueous writing ink may have a post-shear loss factor tanδ of about 8 to about 60, more specifically about 11 to about 50, particularly about 15 to about 40. The post-shear loss factor tanδ is about 1000 seconds -1For about 30 seconds, with vibration measurement (frequency = about 1 Hz, shear about 20 Pa), after pre-shearing, it can be measured at about 20 °C using a cone and plate rheometer such as the Malvern Kinexus with a cone of about 40 mm and an angle of about 4°.

[0088] In a second aspect, the present disclosure relates to a non-aqueous writing ink comprising a solvent, a colorant, a resin, a gelling agent, and a homopolymer or copolymer of vinylpyrrolidone, wherein the gelling agent is a mixture of silica particles and fatty acid amide wax, and the homopolymer or copolymer of vinylpyrrolidone is present in an amount of about 0.05 to about 0.6% by weight based on the total weight of the ink.

[0089] The embodiments described for the above first aspect of the present disclosure can be combined equivalently with the aforementioned second aspect of the present disclosure. In particular, it may be advantageous that the non-aqueous writing ink contains, or may consist of, the following components in amounts based on the total weight of the ink: about 55 to about 75% by weight of a solvent selected from polyethylene glycol ether, polypropylene glycol ether, phenoxyethanol, 1-phenoxy-2-propanol, or a mixture thereof, about 10 to about 30% by weight of a colorant, about 0.10 to about 0.60% by weight of polyvinylpyrrolidone having a weight average molecular weight of about 600 to about 1900 kDa, about 0.15 to about 0.60% by weight of fatty acid amide wax, about 0.15 to about 0.60% by weight of hydrophilic silica, and the remaining components selected from resins and additives. More specifically, the non-aqueous writing ink contains, or may consist of, the following components in amounts based on the total weight of the ink: about 55 to about 75% by weight of 1-phenoxy-2-propanol, about 10 to about 30% by weight of a colorant, about 0.10 to about 0.60% by weight of polyvinylpyrrolidone having a weight average molecular weight of about 600 to about 1900 kDa, about 0.15 to about 0.60% by weight of fatty acid amide wax containing N,N'-ethylene-bis-fatty acid amide, particularly N,N'-ethylene-bis-fatty acid amide having the following formula (I)

Chemical formula

[0090] In particular, for non-aqueous writing ink, in amounts relative to the total weight of the ink, the following components: about 55 to about 75% by weight of a solvent selected from polyethylene glycol ether, polypropylene glycol ether, phenoxyethanol, 1-phenoxy-2-propanol, or mixtures thereof, about 10 to about 30% by weight of a colorant, about 0.10 to about 1.0% by weight of polyvinyl butyral having a weight average molecular weight of about 600 to about 1900 kDa, about 0.15 to about 0.60% by weight of a fatty acid amide wax, about 0.15 to about 0.60% by weight of hydrophilic silica, and the remaining components selected from resins and additives, may advantageously comprise or consist of these. More specifically, for non-aqueous writing ink, in amounts relative to the total weight of the ink, the following components: about 55 to about 75% by weight of 1-phenoxy-2-propanol, about 10 to about 30% by weight of a colorant, about 0.10 to about 1.0% by weight of polyvinyl butyral having a weight average molecular weight of about 600 to about 1900 kDa, about 0.15 to about 0.60% by weight of a fatty acid amide wax comprising N,N'-ethylene-bis-fatty acid amide, in particular N,N'-ethylene-bis-fatty acid amide having the following formula (I)

Chemical formula

[0091] In particular, it may be advantageous for the non-aqueous writing ink to contain, or consist of, the following components in amounts based on the total weight of the ink: about 55 to about 75% by weight of a solvent selected from polyethylene glycol ether, polypropylene glycol ether, phenoxyethanol, 1-phenoxy-2-propanol, or mixtures thereof; about 10 to about 30% by weight of a colorant; about 0.10 to about 0.60% by weight of polyvinylpyrrolidone having a weight average molecular weight of about 600 to about 1900 kDa and polyvinyl butyral having a weight average molecular weight of about 600 to about 1900 kDa; about 0.15 to about 0.60% by weight of a fatty acid amide wax; about 0.15 to about 0.60% by weight of hydrophilic silica; and the remaining components selected from resins and additives. More specifically, the non-aqueous writing ink contains, in amounts based on the total weight of the ink: about 55 to about 75% by weight of 1-phenoxy-2-propanol; about 10 to about 30% by weight of a colorant; about 0.10 to about 0.60% by weight of polyvinylpyrrolidone having a weight average molecular weight of about 600 to about 1900 kDa; about 0.15 to about 0.60% by weight of a fatty acid amide wax containing N,N'-ethylene-bis-fatty acid amide, particularly N,N'-ethylene-bis-fatty acid amide having the following formula (I) [Chemical formula] about 0.15 to about 0.60% by weight; about 0.15 to about 0.60% by weight of hydrophilic silica; about 5 to about 15% by weight of a resin; and additives, particularly the remaining components being the additives as defined above. It may be advantageous for the ink to contain, or consist of, these components. In a third aspect, the present disclosure relates to a process for preparing a writing instrument according to the first aspect of the present disclosure or a non-aqueous writing ink according to the second aspect of the present disclosure. The process is not particularly limited.

[0092] In a third aspect, the present disclosure relates to a process for preparing a writing instrument according to the first aspect of the present disclosure or a non-aqueous writing ink according to the second aspect of the present disclosure. The process is not particularly limited.

[0093] Thus, in some embodiments, the non-aqueous writing ink can be prepared by the following steps. In one step, a first preliminary mixture containing silica particles in a solvent is formed. The temperature in this step can be from about 30 to about 70 °C. The first preliminary mixture can be mixed at a shear rate of about 20 to about 25 m / sec. In another step, a second preliminary mixture containing fatty acid amide wax in a solvent is formed. The temperature in this step can be from about 30 to about 70 °C. It should be understood that the step of forming the first preliminary mixture can be carried out with only a part of the solvent contained in the final writing ink. Then, the first preliminary mixture can be combined with the remaining components of the writing ink.

[0094] However, in some embodiments, it may be advantageous for the fatty acid amide wax to be activated by the formation of a preliminary mixture in a solvent (the second preliminary mixture), preferably a solvent as described above for the ink, in particular a glycol ether, before addition into the writing ink containing the (remaining) solvent, the colorant, the silica particles, and optionally, additives. Without wishing to be bound by theory, it is believed that such activation may enable the diffusion of the fatty acid amide wax and thus the acquisition of a stronger gel network. Advantageously, the activation step (formation of the preliminary mixture) can be carried out at an exact temperature and shear stress.

[0095] Therefore, in some embodiments, the non-aqueous writing ink can be prepared by the following steps. In one step, a first preliminary mixture containing silica particles in a solvent is formed. The temperature in this step can be from about 30°C to about 70°C. The first preliminary mixture can be mixed at a shear rate of about 20 to about 25 m / sec. In another step, a second preliminary mixture containing fatty acid amide wax in a solvent is formed. The temperature in this step can be from about 30°C to about 70°C. The second preliminary mixture can be mixed at a shear rate of about 20 to about 25 m / sec. It should be understood that the steps of forming the first and second preliminary mixtures can be carried out with only a part of the solvent contained in the final writing ink. Then, the first and second preliminary mixtures can be combined with the remaining components of the writing ink.

[0096] To obtain the preliminary mixture, a rotor-stator disperser can be used. The activation of the fatty acid amide wax can be observed by measuring the static viscosity of the preliminary mixture. When the activation is completed, the static viscosity becomes maximum (the diffusion of the fatty acid amide wax increases the static viscosity).

[0097] The embodiments described for the above first aspect of the present disclosure can be combined equivalently with the aforementioned third aspect of the present disclosure.

[0098] Hereinafter, the present disclosure will be described in more detail by way of examples.

Examples

[0099] Measurement method The measurements of the ink and the pen were performed as follows.

[0100] 1. Measurement of residual viscosity The viscosity of the ink was measured at 20°C using a Malvern Kinexus cone and plate rheometer with a 40 mm cone and a 4° angle at a shear rate of 0.01 second -1 .

[0101] 2. Measurement of shear viscosity The viscosity of the ink was measured at 20°C using a Malvern Kinexus cone and plate rheometer with a 40 mm cone and a 4° angle at a shear rate of 100 seconds. -1

[0102] 3. Determination of the shear thinning index Formula: Shear thinning index = (Measurement of the remaining viscosity at 0.01 seconds at 20°C, P4° / 40 mm) / (Measurement of the remaining viscosity at 100 seconds at 20°C, P4° / 40 mm) -1 -1

[0103] 4. Measurement of tan delta at rest The measurement was carried out using a Malvern Kinexus cone and plate rheometer with a 40 mm cone and a 4° angle, with vibration measurement (frequency = 1 Hz, shear 20 Pa).

[0104] 5. Measurement of tan delta after shear at 1000 seconds -1 The measurement was carried out using a Malvern Kinexus cone and plate rheometer with a 40 mm cone and a 4° angle after pre-shearing the sample for approximately 1000 seconds (to simulate the writing process) for about 30 seconds. -1

[0105] 6. Penetration after storage at 23°C for 24 hours This test measures the amount of ink leaking from the tip of the ball pen when the ball pen is stored tip-down at 23°C for 1 day. This process was carried out as follows (tested with 10 pens). 1. Ball pen start = Write with the pen to reduce viscosity. 2. Wipe off the ink from the tip with non-cotton paper 3. Store the ball pen at 23°C / 50% RH with the tip down for 24 hours 4. Transfer the ink drop from the pen tip to the paper. Rotate the tip of each pen on the test sheet 360° to transfer any ink penetration to the test sheet. 5. Cover the penetration display area with a transparent piece of tape 6. Use a ceramic roulette to spread the ink stain into a circular stain. 7. Measure the diameter of each stain (record the minimum diameter that incorporates the entire spot) 8. Calculate the average spot size (mm) from all 10 samples.

[0106] 7. Storage for 1 week at 40 °C / 80% RH for penetration In this test, the amount of ink leaking from the tip of a ballpoint pen is measured when the ballpoint pen is stored with the tip facing down at 40 °C / 80% RH for 1 week. This test simulates maintaining the pen in a shirt pocket close to the body. This process was carried out as follows (test with 10 pens). 1. Ballpoint pen start = Write with the pen to reduce viscosity. 2. Wipe off the ink from the tip with non-cotton paper 3. Store the ballpoint pen at 40 °C / 80% RH with the tip down for 7 days. 4. Transfer the ink drop from the pen tip to the paper. Rotate the tip of each pen on the test sheet 360° and transfer any ink penetration to the test sheet. 5. Cover the penetration display part with a transparent piece of tape 6. Use a ceramic roulette to spread the ink stain into a circular stain. 7. Measure the diameter of each stain (record the minimum diameter that incorporates the entire spot) 8. Calculate the average spot size (mm) from all 10 samples.

[0107] 8. Cleanliness of mechanical writing This test evaluates the mechanical writing quality of a pen under given test conditions during the first 20 meters of mechanical writing. Equipment: 1. Air-conditioned and humidity-controlled room: 23 °C (±2°) 50% RH (±5%) 2. Writing machine operating according to the following guidelines: a) General conditions: Writing angle of 70° (0, +10) Circumference 100 mm Total weight pen / holder / additional weight: 140 - 160 grams ISO12757 test paper Writing surface of polished stainless steel with felt attached below b) Mechanical parameters: Writing speed of 4.5 m / min (±0.5) 0.6 mm spacing between circles (±0.2) on Minitek APC or position 5 on Mikron 1 axial pen rotation per 100 circles Writing length: 20 meters c) Process: 1. Install the cartridge inside the barrel 2. Draw a loop to start the pen 3. Select positions at 0.6 mm intervals and record 20 meters on the counter 4. Execute the test by pressing "Pen rotation" 5. Calculate the average score of the tested pens, excluding pens that have not started 6. Evaluate cleanliness, i.e., the thickness on the line is approximately uniform (presence of bleeding)

[0108] 9. Regularity of mechanical writing This test evaluates the mechanical writing quality of the pen under given test conditions during the first 20 meters of mechanical writing. Equipment: 1. Air - conditioned and humidity - controlled room: 23°C (±2°) 50% RH (±5%) 2. Writing machine operating according to the following guidelines: a) General conditions: Writing angle of 70° (0, +10) Circumference 100 mm Total weight pen / holder / additional weight: 140 - 160 grams ISO12757 test paper Writing surface of polished stainless steel with felt attached below b) Mechanical parameters: Writing speed of 4.5 m / min (±0.5) 0.6 mm spacing between circles (±0.2) on Minitek APC or position 5 on Mikron One axial pen rotation per 100 yen Writing length: 20 meters c) Process: 1. Install the cartridge into the barrel 2. Draw a loop to start the pen 3. Select positions at 0.6 mm intervals and record 20 meters on the counter 4. Execute the test by pressing "Pen rotation" 5. Calculate the average score of the tested pens, excluding pens that have not started 6. Evaluate the regularity, i.e., being almost uniform in color during writing (presence of white within the line)

[0109] 10. Complete ink compensation This test reflects the "durable distance" of the pen, i.e., the ability of the pen to write until writing stops. When the pen writes until the cartridge is completely empty, the sample is marked as "Yes". Otherwise, the sample is marked as "No".

[0110] 11. Cleanliness of handwriting This test measures the uniformity in the darkness of the written line. The regularity of the darkness of the written line was visually evaluated and rated at intervals of 1. The rating scale was as follows 10: Very clean, no excessive parts, no bleeding 0: Not clean, with excessive parts and ink bleeding on the written line

[0111] 12. Regularity of handwriting This test measures the color uniformity during writing. The samples were visually inspected for the "channels" in the brighter areas or darker areas and in the center of the line. The rating scale had an interval of 1 and was as follows 10: Very regular, no white within the line 0: Not regular

[0112] 13. Gouging In this test, after manual writing, it is evaluated whether ink drips from the tip. It is a visual evaluation of the tip after writing a sentence.

[0113] Example 1 According to the procedure outlined for the third aspect of the present disclosure, the following non-aqueous writing ink was prepared. [Table 1]

[0114] The rheological properties of the ink according to Example 1 were as follows. ● Viscosity at rest = 74990 cP ● Viscosity under shear = 2765 cP ● Tan delta at rest = 6.9 ● Tan delta after shear = 29.7

[0115] Example 2 and Comparative Examples 1-9 Further non-aqueous writing inks were prepared as described for Example 1, with the ink composition shown below as the only variable. The dye, defoamer, and clear drain additive remained unchanged. The prepared ink was injected into a cartridge. All experimental tests were conducted after conditioning on a stabilized cartridge, i.e., after storage at 23 °C and 50% RH for at least one week after injection. This point is referred to as T = 0. The writing system is a retractable cartridge with a 1 mm tip.

[0116] Table 1 below shows the compositions used, including the above Example 1 for reference. [Table 2]

[0117] The performance of the examples and comparative examples is shown in Figure 1.

[0118] As is clear from the comparison between Comparative Example 1 and Example 1, replacing 0.15 wt% of the SK resin binder with a homo- or copolymer of 0.15 wt% vinyl pyrrolidone avoids the problem of ink gooping while providing a well-balanced performance that highly satisfies other writing performance criteria. Without wishing to be bound by theory, the presence of the homo- or copolymer of vinyl pyrrolidone is thought to modify the gelling network such that the dynamic viscosity rapidly returns to the static viscosity immediately after the writing event, and thus avoid gooping. As is clear from Comparative Examples 5-7, replacing the SK resin binder with a homo- or copolymer of vinyl pyrrolidone in an amount greater than 0.6 wt% destroys this effect and gooping returns. Further increasing the level of the homo- or copolymer of vinyl pyrrolidone (Comparative Example 5) changes the gelling network again, resulting in avoidance of gooping, but the regularity of handwriting and machine writing becomes unacceptably low. The table in Figure 1 further shows that overall performance is optimal when the resin is used in combination with a homo- or copolymer of vinyl pyrrolidone, fatty acid amide wax, and hydrophilic silica.

[0119] Example 3 The following non-aqueous writing ink can be prepared.

Table 3

[0120] Further embodiments according to the present disclosure are listed below.

[0121] 1. A writing instrument, in particular a pen such as a ballpoint pen containing a non-aqueous writing ink containing a solvent, a colorant, a resin, a gelling agent, and polyvinyl alcohol acetalized with an aldehyde containing from 1 to about 6 carbon atoms, the gelling agent contains a mixture of silica particles and fatty acid amide wax, the polyvinyl alcohol acetalized with an aldehyde containing from 1 to about 6 carbon atoms is present in an amount of about 0.05 to about 1.0 wt% based on the total weight of the ink.

[0122] 2. The polyvinyl alcohol is acetalized with an aldehyde containing 2, 2 or 3, 2 to 4, or 2 to 5 carbon atoms, and in particular, the polyvinyl alcohol acetalized with an aldehyde containing 1 to about 6 carbon atoms is polyvinyl butyral, and the writing instrument according to clause 1.

[0123] 3. The polyvinyl alcohol acetalized with an aldehyde containing 1 to about 6 carbon atoms, in particular, polyvinyl butyral, has a weight average molecular weight of more than about 200 kDa, specifically, about 400 to about 2300 kDa, more specifically, about 450 to about 2000 kDa, and in particular, about 600 to about 1900 kDa, and the writing instrument according to clause 2.

[0124] 4. The weight of the polyvinyl alcohol acetalized with an aldehyde containing 1 to about 6 carbon atoms is less than the weight of the mixture of silica particles and fatty acid amide, and the writing instrument according to any one of clauses 1 to 3.

[0125] 5. The silica particles include hydrophilic silica particles, and in particular, the hydrophilic silica particles are present in an amount of about 0.10 to about 0.60% by weight based on the total weight of the ink, and the writing instrument according to any one of clauses 1 to 4.

[0126] 6. The fatty acid amide wax is N, N'-ethylene-bis-fatty acid amide, and in particular, the following formula (I)

Chemical formula

[0127] 7. The gelling agent is present in an amount of about 0.1 to about 1.2% by weight, more specifically, about 0.15 to about 0.60% by weight based on the total weight of the ink, and the writing instrument according to any one of clauses 1 to 6.

[0128] 8. The solvent is selected from the group consisting of glycol ethers, alcohols, and mixtures thereof, and more specifically, the solvent is polyethylene glycol ether, polypropylene glycol ether, phenoxyethanol, 1-phenoxy-2-propanol, or a mixture thereof. The writing instrument according to any one of clauses 1 to 7.

[0129] 9. The solvent is present in an amount of about 35 to about 80% by weight, more specifically, about 45 to about 75% by weight, based on the total weight of the ink. The writing instrument according to any one of clauses 1 to 8.

[0130] 10. The colorant is a dye, particularly a dye selected from the group consisting of azo dyes, triarylmethane dyes, phthalocyanine derivative dyes, xanthene dyes, and mixtures thereof. The writing instrument according to any one of clauses 1 to 9.

[0131] 11. The colorant is present in an amount of about 5 to about 30% by weight, particularly about 7 to about 28% by weight, based on the total weight of the ink. The writing instrument according to any one of clauses 1 to 10.

[0132] 12. The non-aqueous writing ink further comprises one or more additives selected from the group consisting of one or more additives, particularly thickeners, clear drain agents, tackifiers, lubricants, dispersants, and mixtures thereof. The writing instrument according to any one of clauses 1 to 11.

[0133] 13. The non-aqueous writing ink is in an amount based on the total weight of the ink about 0.1 to about 1.0% by weight of polyvinyl butyral having a weight average molecular weight of about 450 to about 2000 kDa, about 0.15 to about 0.60% by weight of fatty acid amide wax, and about 0.15 to about 0.60% by weight of hydrophilic silica. The writing instrument according to any one of clauses 1 to 12.

[0134] 14. The writing instrument according to any one of clauses 1 to 13, wherein the non-aqueous writing ink contains a resin selected from polyester resins, polyurethane resins, ketone resins, ether resins, and mixtures thereof, and the resin is optionally present in an amount of about 3% to about 30%, specifically about 3% to about 25%, particularly about 5% to about 20% based on the total weight of the ink.

[0135] 15. The writing instrument according to clause 14, wherein the ink contains about 55% to about 75% by weight of 1-phenoxy-2-propanol.

[0136] 16. The fatty acid amide wax is N, N'-ethylene-bis-fatty acid amide, particularly the following formula (I)

Chemical formula

[0137] 17. The writing instrument according to any one of clauses 1 to 16, wherein the ink has a static loss coefficient tanδ of about 4 to about 25, more specifically about 4 to about 12, particularly about 5 to about 10, and particularly a shear loss coefficient of about 8 to about 60, more specifically about 10 to about 50, particularly about 15 to about 40.

[0138] 18. The non-aqueous writing ink contains, in amounts based on the total weight of the ink, the following components: About 55% to about 75% by weight of the solvent is selected from polyethylene glycol ethers, polypropylene glycol ethers, phenoxyethanol, 1-phenoxy-2-propanol, or mixtures thereof, About 10% to about 30% by weight of a colorant, and About 0.10% to about 1.0% by weight of polyvinyl butyral having a weight average molecular weight of about 600 to about 1900 kDa, About 0.15% to about 0.60% by weight of a fatty acid amide wax, About 0.15% to about 0.60% by weight of hydrophilic silica, The remaining components selected from resins and additives, and the writing instrument according to any one of clauses 1 to 17.

[0139] 19. The non-aqueous writing ink contains, in amounts based on the total weight of the ink, the following components: about 55 to about 75% by weight of 1-phenoxy-2-propanol, and about 10 to about 30% by weight of a colorant, and about 0.10 to about 1.0% by weight of polyvinyl butyral having a weight average molecular weight of about 600 to about 1900 kDa, and N,N'-ethylene-bis-fatty acid amide, particularly, the following formula (I)

Chemical formula

[0140] 20. A non-aqueous writing ink containing a solvent, a colorant, a resin, a gelling agent, and polyvinyl alcohol acetalized with an aldehyde containing 1 to about 6 carbon atoms, wherein the gelling agent is a mixture of silica particles and a fatty acid amide wax, and the polyvinyl alcohol acetalized with an aldehyde containing 1 to about 6 carbon atoms is present in an amount of about 0.05 to about 1.0% by weight based on the total weight of the ink.

[0141] 21. A process for preparing the writing instrument according to any one of clauses 1 to 19 or the non-aqueous writing ink according to clause 20, the non-aqueous writing ink containing a solvent, a colorant, a resin, a gelling agent, and polyvinyl alcohol acetalized with an aldehyde containing 1 to about 6 carbon atoms, wherein the gelling agent contains a mixture of silica particles and a fatty acid amide wax, and the polyvinyl alcohol acetalized with an aldehyde containing 1 to about 6 carbon atoms is present in an amount of 0.05 to 1.0% by weight based on the total weight of the ink. a) Forming a first preliminary mixture containing silica particles in a solvent at a temperature of about 30 to about 70 °C and a shear rate of about 20 to about 25 m / s; b) A process prepared by combining the first preliminary mixture with the remaining components of the non-aqueous writing ink.

[0142] Certain embodiments of the present disclosure are disclosed for illustrative purposes, and those skilled in the art will understand that various modifications and changes can be made without departing from the spirit of the present disclosure. It should also be understood that such modifications and changes are incorporated within the scope of the present disclosure and the appended claims.

Claims

1. A writing instrument containing a non-aqueous writing ink comprising a solvent, a colorant, a resin, a gelling agent, and a homo- or copolymer of vinylpyrrolidone or a polyvinyl alcohol acetalized with an aldehyde containing 1 to 6 carbon atoms; the gelling agent comprises a mixture of silica particles and a fatty acid amide wax; the gelling agent is present in an amount of 0.1 to 1.2 wt. %, based on the total weight of the ink; the vinylpyrrolidone homo- or copolymer, if present, is present in an amount of 0.05 to 0.6 wt. %, based on the total weight of the ink; the polyvinyl alcohol acetalized with an aldehyde containing 1 to 6 carbon atoms, when present, is present in an amount of 0.05 to 1.0 wt. %, based on the total weight of the ink; the combined amount of the vinylpyrrolidone homo- or copolymer and the polyvinyl alcohol acetalized with an aldehyde containing 1 to 6 carbon atoms, when both are present, is 0.05 to 1.0 wt. %, based on the total weight of the ink; A writing instrument, wherein the non-aqueous writing ink has a static viscosity at 20°C of 30,000 cps to 150,000 cps.

2. 2. The writing instrument of claim 1, wherein the vinylpyrrolidone homo- or copolymer is polyvinylpyrrolidone.

3. 3. The writing instrument of claim 2, wherein the polyvinylpyrrolidone has a weight average molecular weight greater than 200 kDa.

4. 4. The writing instrument according to claim 1, wherein the weight of the vinylpyrrolidone homo- or copolymer is less than the weight of the mixture of silica particles and fatty acid amide wax.

5. 5. The writing instrument according to claim 1, wherein the silica particles comprise hydrophilic silica particles, and the hydrophilic silica particles are present in an amount of 0.10 to 0.60 wt %, based on the total weight of the ink.

6. The writing instrument of any one of claims 1 to 5, wherein the fatty acid amide wax comprises N,N'-ethylene-bis-fatty acid amide.

7. 7. The writing instrument of claim 1, wherein the gelling agent is present in an amount of 0.1 to 1.2 wt. %, more specifically 0.15 to 0.60 wt. %, based on the total weight of the ink.

8. 8. The writing instrument of claim 1, wherein the solvent is selected from the group consisting of glycol ethers, alcohols, and mixtures thereof, and / or the solvent is present in an amount of 35 to 80% by weight, based on the total weight of the ink, or the ink comprises 55 to 75% by weight of 1-phenoxy-2-propanol.

9. 9. A writing instrument according to any preceding claim, wherein the colorant is a dye and / or the colorant is present in an amount of 5 to 30% by weight, based on the total weight of the ink.

10. The writing instrument of any one of claims 1 to 9, wherein the non-aqueous writing ink further comprises one or more additives.

11. The non-aqueous writing ink comprises, in an amount based on the total weight of the ink: 0.1 to 0.6 wt. % polyvinylpyrrolidone having a weight average molecular weight of 450 to 2000 kDa, 0.15 to 0.60 wt. % of said fatty acid amide wax, and 11. A writing instrument according to any one of claims 1 to 10, comprising 0.15 to 0.60% by weight of hydrophilic silica.

12. 12. A writing instrument according to any one of claims 1 to 11, wherein the non-aqueous writing ink comprises a resin selected from polyester resins, polyurethane resins, ketone resins, ether resins, and mixtures thereof, the resin optionally being present in an amount of 3 to 30%, relative to the total weight of the ink.

13. 13. A writing instrument according to any one of claims 1 to 12, wherein the ink has a loss factor at rest tan δ of 3 to 15 and / or a loss factor after shear of 8 to 60.

14. 1. A non-aqueous writing ink comprising a solvent, a colorant, a resin, a gelling agent, and a homo- or copolymer of vinylpyrrolidone, wherein the gelling agent is a mixture of silica particles and a fatty acid amide wax, the gelling agent is present in an amount of 0.1 to 1.2% by weight, based on the total weight of the ink, the homo- or copolymer of vinylpyrrolidone is present in an amount of 0.05 to 0.6% by weight, based on the total weight of the ink, and the combined amount of the homo- or copolymer of vinylpyrrolidone and polyvinyl alcohol acetalized with an aldehyde containing 1 to 6 carbon atoms, if both are present, is 0.05 to 1.0% by weight, based on the total weight of the ink, and the non-aqueous writing ink has a static viscosity of 30,000 cps to 150,000 cps at 20°C.

15. 15. A process for preparing a writing instrument according to any one of claims 1 to 13 or a non-aqueous writing ink according to claim 14, comprising: a non-aqueous writing ink comprising a solvent, a colorant, a resin, a gelling agent, and a homo- or copolymer of vinylpyrrolidone, wherein the gelling agent comprises a mixture of silica particles and a fatty acid amide wax, and the homo- or copolymer of vinylpyrrolidone is present in an amount of 0.05 to 0.6 wt. %, based on the total weight of the ink; a) forming a first premix comprising silica particles in a solvent at a temperature of 30-70°C and a shear rate of 20-25 m / sec; b) combining said first pre-mixture with the remaining ingredients of said non-aqueous writing ink.

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