MXPA98003487A - Ink based on soft sliding water, quese can be deleted, and boligrafo that the conti - Google Patents

Abstract

An erasable ink, water-based, smooth glide and a pen that contains it. In a preferred embodiment, the ink includes a mixture of three different aqueous non-carboxylic styrene-butadiene emulsions, a water-insoluble or water-dispersible pigment and a smooth slip agent and viscosity adjustment in the form of a silicate clay. The ink further comprises an antioxidant preparation including tocopherol and vitamin C, to extend the time during which the ink remains erasable after it has been applied to a substrate, a mild gliding stabilizer in the form of potassium oleate, to avoid the undesirable coagulation of the styrene-butadiene copolymer due to the sliding stress, a pH adjusting agent, in the form of triethanolamine, to modify the pH, in the form of triethanolamine, to modify the pH of the compound to reach a pH of between 9 and 10 and an antisecretory agent in the form of a 3: 1 mixture of sorbitol and glycerin, respectively. The pen includes a barrel (13) to store a certain amount of ink, the barrel is made of polypropylene and has the upper end open (15), a hollow point (29) made of stainless steel, a nickel-silver alloy or polyoxymethylene , with an upper end (31) and a lower end (33), said upper end is shaped to constitute a bushing for a ball (35), a ball (41) that rotates and is housed in said bushing (35), manufactured with sintered ceramic material, and an elongated hollow connector (21) made of polyoxymethylene having the upper end open (23) and adapted to receive the lower end of said hollow tip and the lower end (25) open and adapted to receive the upper end (15) open from the barrel. The pellet (41) has a diameter of about 0.7 mm or greater. The bushing (35) has a maximum interior width that exceeds the diameter of the pellet (41) by approximately 0.015-0.025 mm and is shaped to allow the pellet (41) to move axially within the ferrule a distance of approximately 0.03-0.07

Description

SOFT SLIDING WATER BASED INK, WHICH CAN BE DELETED AND BALLPOINT CONTAINED BACKGROUND OF THE INVENTION The present invention relates, generally, to inks that can be erased and more specifically to erasable inks suitable for use in pens and pens containing erasable inks. When using writing instruments to produce written images, characters or marks that stand out on a demarcated substrate, it is not necessarily desirable to achieve a high degree of indelibility. For example, someone would want to be able to make a mark on a marking substrate that could easily be erased from it with substantially non-abrasive mechanical means, such as with a normal eraser that has a pencil, a dry cloth, etc. In order to be completely erasable, the ink of the marked substrate to which it has been applied must be substantially completely removed, without causing too much damage to the marking substrate. For the reasons discussed below, often such an objective is very difficult to achieve when the marking substrate is porous, as in the case of plain paper sold in stationery stores. The normal paper for writing is essentially a sheet of cellulose fibers oriented disorderly.

In this way, normal writing paper is constituted by solid structural elements, mainly cellulose fibers having many small gaps between them. From the above it can be easily deduced that whoever designs or designs an erasable ink should avoid that the coloring portion of the ink penetrates too much into the holes of the surface on which it is being written because if the ink dye penetrates too much into the holes the subsequent elimination of the dye by mechanical means without causing damage to the described surface can not be achieved. Likewise, it can also easily be seen that in order to erase the writing medium, the dye must be prevented from fixing too permanently, either due to chemical reactions or as a result of simple physical attraction, to the solid elements of the paper substrate. The above possibilities tend to suggest that the erasable ink should contain relatively large dye particles which can not penetrate the voids of the paper substrate. However, this approach to achieving erasable property has not been very successful, especially when the ink comes out of a pen or pen, since it is often difficult for inks that have a relatively large amount of dyes to pass through the very small space existing between the ball and the cap of a ballpoint pen.

Another approach that has been used to try to achieve the erasure in the pens has been to include a resinous material or that forms a mechanically detachable film in the ink that prevents the dye from penetrating the holes of the paper and which attaches to the solid elements of the paper substrate. Among such inks are those of organic or oil-based origin that have high viscosity; for example, at least several thousand CPS and that are used in pens. An example of the aforesaid type of ink is described in U.S. Patent No. 4,407,985, invented by Muller, which was published on October 4, 1983 and which is incorporated by reference herein. The composition of the Muller ink is characterized by having an initial but transient erasability, on an absorbent surface, such as writing paper, by normal pencil erasers when applied with a writing instrument with ballpoint. The Muller ink composition contains polar elastomers, such as copolymer butadiene / acrylonitrile rubbers and vinyl acetate / ethylene copolymer rubbers, and mixtures thereof, either alone or in mixtures with cis-1,4 polyisoprene, ( natural rubber or synthetic rubber), pigment and a solvent system. The polar elastomer is present in a proportion of 14-25% by weight of the ink, and the pigment is present in an amount sufficient to impart color and intensity to a stroke of the ink when it is applied to a substrate. like paper. The solvent system is basically constituted by a volatile component having a boiling point less than about 180 ° C, plus an essentially non-volatile component which includes the pigment vehicle having a boiling point greater than 300 ° C, plus a low viscosity plasticizer having a boiling point greater than 180 ° C but lower than 300 ° C, the solvent system being present in an amount sufficient to impart a final ink viscosity of approximately 1.5 million du cps.

Another example of oil-based erasable ink that is used in pens is described in U.S. Patent No. 4,687,791, invented by Miyajima et al., Published August 18, 1987 and incorporated by reference into this specification. The Miyaji invention ink consists of a rubber component, a volatile solvent, a pigment and a non-volatile solvent, which additionally includes finely divided powder of an inorganic compound that does not react with other ink components contained therein. , a semi-solid substance, a soft solid substance with a boiling point not higher than 130 ° C, a combination of finely divided powder of an inorganic compound which does not react with other ink components contained therein and a semi-solid substance or a combination of finely divided powder of an inorganic compound which does not react with the other ink compounds contained therein and a soft solid substance having a boiling point not higher than 130 ° C. One of the problems that has generally been observed in relation to inks of organic or oil-based origin, both erasable and non-erasable, is that such inks, when used in pens, often do not produce a sensation effect. pleasant to write due to the relatively large amount of force that must be done to get the highly viscous ink of organic origin through the small space between the ball and the cap of the pen. Furthermore, such inks, due to their inherent fluid characteristics, often have the tendency to produce granules and jumps when leaving the pens. Such inks also tend to run unacceptably on normal writing paper and often have toxic substances and bad odor. On the other hand, aqueous inks, boring or not, generally have relatively lower viscosity than oil inks and with them many of the problems related to oil-based inks are avoided; however, also as a result of their relatively low viscosity, aqueous inks generally can not be used in conventional pens. Because of this, aqueous inks have traditionally been used in pens consisting of a combination of an absorbent filler element and one or more absorbent feeding tubes ("canutos") (See, for example, US Patent No. 4,145,148, inventor Fukuoka, which was published on March 20, 1979 and which is incorporated by reference to this descriptive rep. The filling is generally disposed between the reservoir of the pen, and the tips generally interconnect the reservoir around the ball and the pen cap. Alternatively, there are also unfilled pens from which aqueous inks come out, but which have one or more tips. For example, recently in U.S. Patent Nos. 4,671,691, 4,686,246, 5,013,361 and 4,786,198, which are incorporated herein by reference, non-erasable aqueous inks are described for use in unfilled and non-tipped pens. Such inks include a material that gives the ink the property of sliding smoothly, that is, the inks have a relatively high viscosity while at rest (although less viscous than the inks traditionally used in pens), but when subjected to stresses of high slippage produced during writing, much viscosity is lost, for example it is reduced to less than 100 cps. Examples of soft materials described in the aforementioned patents include gums, such as xantham gum. In U.S. Patent No. 5,217,255, the inventors of which are Lin et al., Published June 8, 1993, and incorporated by reference herein, an erasable system is described which includes an element with a porous marking surface and a compound of Erasable marking to apply marks to the porous marking surface. The labeling compound of Lin and others is constituted by an aqueous dispersion of particles of polymeric materials forming a film, and a dye. It is assumed that the labeling compound of Lin et al. Constitutes a substantially water-soluble erasable residue on a porous marking surface. Among the especially preferred polymeric materials of the Lin labeling composition and others, include styrene copolymers, such as styrene-butadiene, PLIOLITE 3757, which in the Lin patent and others is described as a butadiene-styrene latex which it can be purchased from the Goodyear Tire and Rubber Company and contains approximately 70% by weight of styrene-butadiene, which Lin and others point to as an example of suitable polymeric material to form a film. The labeling compound of Lin and others may include ingredients to control or regulate the rheological properties of the labeling composition. Such ingredients include thixotropic or gelling agents such as clays, silicas, or binder polymeric binder materials not water soluble, water soluble or water miscible, or materials that supply soft polymeric glidants, such as xantham gum, among others. It is said that xantham gum is the preferred material for controlling rheological properties, and preferred amounts of xantham gum are between about 0.05 to 2% by weight of the compound. In U.S. Patent No. 5,389,717, to Santini et al., Published on February 14, 1995, which is incorporated by reference to this specification, a marking compound is described which is said to be erased with a common eraser of pencil for a prolonged period of time, of a porous marking substrate. The Santinl et al compound includes a non-carboxylic styrene-butadiene copolymer resin, a dye and an aqueous solvent. The PLIOLITER® 2108, which is said to have a styrene-butadiene ratio of 29:71 and can be purchased from the Goodyear Tire and Rubber Company, which is the especially preferred resin used in the Santini compound and others. The Santini compound and others may also include additives, such as coalescing agents, water soluble or associative thickeners, extractants, surfactants that are preferably non-carboxylic, and the like. It is said that the composite of Santini and others is suitable for use on porous tip writing instruments, such as felt tip markers; however, it is said that the compound of Santini and others is not limited to such markers and can be used in pens and fountain pens, and in paints to be applied by brush, rollers, pneumatic brushes and the like. In the commonly assigned PCT application No. PCT / US93 / 10231, which was published on May 11, 1994 with International Publication Number WO 94/10251 which is incorporated by reference to this specification, an erasable compound is described for write suitable for use in pens with porous tip and in pens. According to one embodiment, the compound is adapted for use in unfilled and non-padded pens, and is composed of a non-carboxylated styrene-butadiene latex emulsion, a water-soluble pigment and tragacanth gum. The compound may also include additives such as a fluorochemical surfactant plus a mixture with a ratio of 2: 1 Sorbitol and glycerin. The aforementioned patent describes the use of a ceramic sphere instead of a metal sphere in a ballpoint pen.

One problem that the present inventors have observed when using erasable aqueous inks of the type described above, in conventional pens, is that such inks tend to corrode pen components that are in contact therewith. Another problem is that such inks tend to be unstable and are easily agglomerated by sliding or pH efforts. Such efforts are common during the mixing of such inks, when filling the pens and when such ink comes out when pens are used. Another problem is that such inks tend to have less than optimal performance with regard to writing, erasability since the ink dries (when the pen is not covered and can not be used because the ink has dried off the tip of the pen) . It is an object of the present invention to provide a novel aqueous erasable ink for use in pens. Yet another object of the present invention is to provide an erasable ink as described above that can be used to make erasable marks on porous marking substrates and non-porous marking substrates using substantially non-abrasive mechanical means. For purposes of the present specification and claims "porous marking substrate" is defined as a marking substrate sufficiently porous to allow dyes of the type that are generally found in conventional non-erasable inks to penetrate into the same and which, when placed in contact with the present compound, causes the present emulsion to decompose. Examples of conventional porous marking substrates include, but are not limited to, plain writing paper and similar papers that have been treated in such a manner that when in contact with water, their ions (e.g., protons and / or cations) dissolve.

For purposes of the present specification and claims, "non-porous marking substrate" is defined as a substrate that is not sufficiently porous or to allow dyes of the type that are generally found in conventional non-erasable inks to penetrate into it. which, when contacted with the present compound, causes the present emulsion to decompose. Examples of non-porous marking substrates include, but are not limited to, writable, soft surface panels made of glass, plastic, metal, closed porosity wood, coated paper, and the like. Also for purposes of the present specification and claims, the term "substantially non-abrasive mechanical means" includes, but is not limited to, dry cloths, fabrics, normal pencil erasers and the like. Yet another object of the present invention is to provide an erasable ink as described above, which retains a high degree of erasability over a long period of time. In addition to the foregoing and other objects that will be described or will be apparent later in this specification, an ink that can be erased from porous and non-porous marking substrates is provided with substantially non-abrasive mechanical means, such ink being constituted by the following: (a) a latex emulsion mixture including a first non-carboxylic styrene-butadiene latex emulsion, and a second non-carboxylic styrene-butadiene latex emulsion, said latex emulsion blend being characterized by being capable of transforming, after coming into contact with the surface of a porous marking substrate of a first state in which said latex emulsion mixture is stable, to a second state in which said latex emulsion mixture is unstable and in which the styrene-butadiene phase quickly agglomerates to form an adherent film that is deposited directly on the surface of the the substrate of porous marking without adhering too much to it; (b) a dye dispersed in the latex emulsion mixture, the dye being characterized by being associated with the adherent rubber phase film when said latex emulsion mixture is transformed to said second state; and (c) a mild displacement agent that regulates its viscosity. Preferably, the smooth-moving agent that regulates its viscosity includes an inorganic clay material such as a synthetic smectic clay of sodium silicate lithium magnesium hydrate which is added to the ink in an amount sufficient to provide it with a viscosity from about 30 to 300 cps when measured at 20 ° C using a rotating viscometer in which a tapered cone rotates at a fixed speed to provide a sliding speed of 0.2 reciprocal seconds. According to one embodiment, the aforementioned latex emulsion mixture includes a first non-carboxylic styrene-butadiene latex emulsion containing approximately 40% solids total by weight and when it is at 25 ° C temperature it has a Brookfield viscosity of about 30 cps, a pH of about 10.5-11.7, a Mooney value of about 150-160, a surface tension of about 55-65 dynes / cm, a particle size of about 650 Angstroms and a styrene content of about 21-29% (preferably between 21-25%), and a second non-carboxylic styrene-butadiene latex emulsion containing approximately 70% solids total by weight and that when at 25 ° C temperature has a Brookfield viscosity of about 1200 cps, a pH of about 10.0-10.5, a Mooney value of about 70-75, a surface tension of about 32-36 dynes / c m, and a combined styrene content of about 22-28%. Preferably, said first non-carboxylic styrene-butadiene latex emulsion constitutes approximately 45-50%, by weight, of the total compound, and said second non-carboxylic styrene-butadiene latex emulsion constitutes approximately 20-25% , by weight, of the total compound, constituting, as a whole, said first and second non-carboxylic styrene-butadiene latex emulsions approximately 70% by weight of the total compound. According to another embodiment, said latex emulsion mixture includes the first and second non-carboxylic styrene-butadiene latex emulsions described above, and also includes a third non-carboxylic styrene-butadiene latex emulsion, said third emulsion containing non-carboxylated styrene-butadiene latex for a total of 47% solids, by weight, and with a Brookfield viscosity, at 25 ° C, of about 200 cps, a pH of about 9.5-10.0, a Mooney value of about 70 -75, a surface tension of approximately 60-65 dynes / cm, a particle size of approximately 640-720 Angstroms and a combined styrene content of approximately 22-26%. Preferably, said first non-carboxylic styrene-butadiene latex emulsion constitutes about 30-50% (and more preferably about 40%), by weight, of the total compound, said second emulsion of styrene-butadiene latex. non-carboxylic acid constitutes approximately 5-20% (and more preferably approximately 10%), by weight, of the total compound, and said third non-carboxylic styrene-butadiene latex emulsion constitutes approximately 10-30% ( and more preferably about 20%), by weight of the total of the compound, taken together, said first and second and third non-carboxylic styrene-butadiene latex emulsions constitute approximately 70% by weight of the total of the compound. According to yet another embodiment, said latex emulsion mixture includes the above-described first and third non-carboxylic styrene-butadiene latex emulsions. Preferably, said first non-carboxylic styrene-butadiene latex emulsion constitutes approximately 30-50%, by weight, of the total compound, and said third non-carboxylic styrene-butadiene latex emulsion constitutes approximately 10-30%, by weight , of the total of the compound, constituting, together, said first and third non-carboxylic styrene-butadiene latex emulsions approximately 70% by weight of the total of the compound. The erasable ink of the present invention preferably also includes an antioxidant, such as a tocopherol (vitamin E), which is used to extend the time during which said compound remains erasable after it has been applied to a marking substrate. The time extension effect of tocopherol can be further improved if the tocopherol is combined with vitamin C. The erasable ink described above also preferably includes an anti-corrosive agent, such as EDTA and / or benzotriazole, which is used to prevent the corrosion caused by the ink to the point of the pen that contains the ink itself. The erasable ink described above further includes, preferably, a soft gliding stabilizing agent, which is added to the compound to prevent coagulation of the discontinuous rubber phase under conditions of high sliding stress, such as during formulation (i.e. , the mixture) of the compound or during the application of the compound to a marking substrate. The preferred soft-slip stabilizing agent is potassium oleate. The erasable ink described above also preferably includes a pH adjusting agent, which is used to modify the pH of the compound to achieve a pH of between 9 and 10. The agent that is particularly preferred is triethanolamine (TEA). The erasable ink described above also preferably includes an anti-seizing agent. Preferably, the anti-seizure agent includes a 1: 1, 2: 1 or 3: 1 mixture of sorbitol and flycerin, respectively. In particular, a 3: 1 mixture of sorbitol and glycerin is preferable. The erasable ink described above may further include an emulsion of alkyl acrylate copolymer which is used to improve the writing softness of the ink. The present invention is also directed to the combination of the erasable ink described above and a writing instrument. Preferably, the writing instrument is a ball-point pen without filling and without a barrel. Preferably, the unfilled and non-fluted pen includes (a) a barrel adapted to store a certain amount of ink and said barrel has the upper end open; (b) a hollow tip, which is made of metal or polyoxymethylene, with an upper end and a lower end and said upper end is formed to form a cap for a ball, (c) a ball that rotates and is housed in said cap; said pellet is made of non-metallic material; and (d) an elongated hollow connector having the upper end open and adapted to receive the lower end of said tip and the lower end open and adapted to receive the upper end of said barrel. Preferably, said barrel is made of polypropylene, said tip is made of polyoxyethylene, stainless steel or a nickel-silver alloy, said pellet is made of tungsten carbide sintered ceramic, and the mentioned elongated hollow connector is manufactured with polyoxymethylene. The ball has an approximate diameter of 0.7 mm or greater and the bushing has a maximum internal width that exceeds the diameter of the ball by approximately 0.015-0.025 mm and has a shape such that it allows the ball to move axially within it at a distance between 0.03 and 0.07 mm. The present invention is further directed to a method for making erasable marks on porous and non-porous marking substrates using the erasable ink and pen described above. Additional objects, as well as features and advantages of the present invention will be set forth in part in the detailed description which follows and in part will be obvious from the detailed description or may be learned by practice in the use of the invention. In the description reference is made to the accompanying drawings which form part of the same and which are presented by way of illustration of specific embodiments of the practice of the invention. These embodiments will be described in sufficient detail to allow those skilled in the art to practice the use of the invention and it is understood that other embodiments may be used and that changes may be made without departing from the scope of the invention. Therefore, the following detailed description should not be taken in a limiting sense and that the scope of the present invention is better defined by the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which by this means are incorporated and constitute a part of this specification, illustrate the preferred embodiment of the invention and, together with the description, serve to explain the principles of the invention. In the drawings, in which like reference numerals represent similar parts: Fig. 1 is a sectional view of the embodiment of an unfilled and non-filled ballpoint pen according to the teachings of the present invention; and Fig. 2 is an enlarged fragmentary sectional view of the unfilled and unbored pen, illustrated in Fig. 1, in which details of the writing end of the pen are illustrated.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to Fig. 1, there is illustrated an embodiment of an unfilled and uncut bobbin made in accordance with the teachings of the present invention and said unfilled and unbored pen is generally represented by reference to the number 11. The pen comprises a barrel element 13, which has the upper end open 15 and the open lower end 17. An amount of ink 101 that will be described later is loaded into the barrel element 13, like a follower 20. gelatinous high viscosity. Preferably, the barrel element 13 is made of polypropylene. The boom also comprises an elongated hollow connector 21. The connector 21 has an open upper end 23 and an open lower end 25. The open lower end 25 is securely positioned within the open upper end 15 of the barrel 13. Preferably, the Connector 21 is manufactured with polyoxymethylene. the pen further comprises a hollow tip 29. The hollow tip 29 has an upper end 31 and a lower end 33. The upper end 31 is shaped to include a bushing 35. The lower end 33 is securely positioned within the upper end 23 of the connector 21. Preferably, the tip 29 is made of stainless steel (for example, SUS 430 with C < 0.05%, SKI.00%, Mn < 2.00%, P < 0.050%, S < 0.150%, Pb> 0.030%, Te <0.08%, Cr <l9.00-21.00% and Mo <1.5-2.5%), a nickel-silver alloy (e.g. 57.0-61.0%, Ni -14.0-16.0%, Mn -0-0.5%, Fe <0.25%, Pb -2.5-3.5% and residual Zn) or with polyoxymethylene. The boom 11 further comprises a ball 41 which rotates in the bushing 35. The ball 41 is made of a non-metallic material, preferably a sintered ceramic, such as silicon carbide, zirconium oxide or aluminum oxide. Tungsten carbide can also be used as material for the pellet, but it is not as preferable as sintered ceramics. Examples of suitable combinations of tips 29 and balls 41 are included, but not limited to the following: (1) polyoxymethylene tip / SiC pellet; (2) stainless steel tip / SiC ball; (3) nickel-silver tip / tungsten carbide ball; (4) nickel-silver tip / SiC pellet; and (5) stainless steel tip / tungsten carbide ball. In Fig. 2 additional details of the ball 41 and the bushing 35 are illustrated. Referring to Fig. 2, the ball 41 has a diameter d of about 0.7 mm or greater. The bushing 35 has a maximum interior width w that exceeds the diameter of the ball by approximately 0.015-0.025 mm. In addition, the bushing 35 is shaped to allow the ball 41 to move axially within the bushing a distance c of about 0.03-0.07 mm. Again, with reference to Fig. 1, the ink 101 is an erasable ink, both in porous and non-porous marking substrates by substantially non-abrasive mechanical means. In accordance with the teachings of the present invention, the ink 101 comprises (a) a latex emulsion mixture that includes one or more non-carboxylic styrene-butadiene latex emulsions; said latex emulsion mixture is characterized by being capable of being transformed, after being contacted with the surface of a porous marking substrate, from a first state in which said latex emulsion mixture is stable, to a second state in to which said latex emulsion mixture is unstable and wherein the styrene-butadiene phase rapidly agglomerates to form a cohesive film that is deposited directly on the surface of the porous marking substrate with little adhesion thereto; (b) a dye dispersed in the latex emulsion mixture: said dye is characterized by being associated with the adherent rubber phase film when said latex emulsion mixture is transformed to the second mentioned state; and (c) a smooth gliding agent and viscosity adjustment. Preferably, the smooth gliding agent and viscosity adjustment includes an inorganic clay material, such as a synthetic smectic clay of sodium silicate lithium magnesium hydrate. Examples of such inorganic clay material include Laponite® XLG rheological additive, Laponite® S rheological additive and Laponite® RD rheological additive, all commercially available from Southern Clay Products, Inc., Gonzales, Texas. Preferably, the clay material is added to the ink in the form of a solution of Laponite® XLG or Laponite® RD in glycerin and water (3% Laponite® / 40% glycerin / 57% water), the solution of Laponite® at 3% constitutes between 3 and 10%, preferably about 7%, by weight, of the ink 101. The addition of the above mentioned amount of the smooth gliding agent and viscosity adjustment gives the ink 101 a viscosity between 30 and 300 cps when measured at 20 ° C using a rotating viscometer in which a tapered cone rotates at a fixed speed to give a sliding effort index of 0.2 reciprocal seconds. The dye of the ink 101 is preferably a water-insoluble or water-dispersible pigment which is also oleophilic. Such pigments may be selected from industry-standard pigments which are well known to be quite suitable for dispersing in aqueous systems and which are capable of associating with the rubber phase of a non-carboxylic styrene-butadiene latex emulsion, as opposed to to be associated with the aqueous phase thereof. Examples of such pigments are natural gas carbon black and ultrafine fluorescent pigments, as well as mixtures thereof. Other pigments, dyes and toners that behave in the same way can also be used in the ink 101. Generally, the dye is present in an amount constituting between 2 and 5%, by weight, of the ink 101 According to one embodiment, the aforementioned latex emulsion mixture includes a first non-carboxylic styrene-butadiene latex emulsion containing approximately 40% solids total by weight and having a viscosity at 25 ° C. Brookfield of about 30 cps, a pH of about 10.5-11.7, a Mooney value of about 150-160, a surface tension of about 55-65 dynes / cm, a particle size of about 650 Angstroms and a combined styrene content about 21-29% (preferably between 21-25%) and a second non-carboxylic styrene-butadiene latex emulsion containing approximately 70% solids by weight and that when is at 25 ° C has a Brookfield viscosity of about 1,200 cps, a pH of about 10.0-10.5, a Mooney value of about 70-75, a surface tension of about 32-36 dynes / cm, and a combined styrene content of approximately 22-26%. Preferably, said first non-carboxylic styrene-butadiene latex emulsion constitutes approximately 45-50%, by weight, of the ink 101, and the second non-carboxylic styrene-butadiene latex emulsion constitutes approximately between 20 and 25% , by weight, of the ink 101, constituting, as a whole, said first and second non-carboxylic styrene-butadiene latex emulsions, approximately 70%, by weight, of the ink 101. According to another embodiment, said mixture of The latex emulsion includes the first and second non-carboxylic styrene-butadiene latex emulsions described above and also includes a third non-carboxylic styrene-butadiene latex emulsion containing approximately 47% solids by weight total and at 25 ° C it has a Brookfield viscosity of approximately 200 cps, a pH of about 9.5-10.0, a Mooney value of about 70-75, a surface tension of about 60-65 dynes / cm, a particle size of about 640-720 Angstroms and a combined styrene content of about 22 -26%. Preferably, said first non-carboxylic styrene-butadiene latex emulsion constitutes approximately 30 to 50% (and more preferably approximately 40%), by weight, of the total compound, said second emulsion of styrene-butadiene-lactam non-carboxylic acid constitutes approximately between 5 and 20% (and more preferably approximately 10%), by weight, of the total compound and said third non-carboxylic styrene-butadiene latex emulsion constitutes approximately between 10 and 30% (and thus more preferably about 20%), by weight, of the total compound; said first, second and third non-carboxylic styrene-butadiene latex emulsions constitute, overall, approximately 70%, by weight, of the total compound. According to yet another embodiment, said latex emulsion mixture includes the first and the third non-carboxylic styrene-butadiene latex emulsions described above. Preferably, said first non-carboxylic styrene-butadiene latex emulsion constitutes approximately 30-50%, by weight, of the total compound and said third non-carboxylic styrene-butadiene latex emulsion constitutes approximately between 10 and 30%, by weight, of the total compound; said first and third non-carboxylic styrene-butadiene latex emulsions constitute, overall, about 70%, by weight, of the total compound. An example of said first non-carboxylic styrene-butadiene latex emulsion is PLIOLITE® LPF-2108 (Goodyear Tire and Rubber Company, Akron, Ohio), which the present inventors understand has been discontinued by Goodyear and has been replaced by PLIOLITE® LPF-3757 (which, apparently, has a different composition to that of the PLIOLITE® LPF-3757 emulsion referred to in Lin and others). An example of said second emulsion of styrene-butadiene latex n? carboxylic is BUTONAL® NS 104 (BASF Corporation, Charlotte, North Carolina) and an example of such a third non-carboxylic styrene-butadiene latex emulsion is BUTOFAN® NS 103 (BASF Corporation, Charlotte, North Carolina), The present inventors have discovered that inks containing a mixture of two or more of the latex emulsions described above are superior to corresponding inks containing only one such latex emulsion, in that the inks containing a mixture thereof allow a greater control over the surface tension of the final composite of the ink compared to inks containing a single latex emulsion. This is significant, since the surface tension has an effect on the degree of penetration of the ink into the marking substrate. For each of the aforementioned embodiments, the time during which the ink 101 remains erasable after being applied to a porous or non-porous marking substrate by increasing the amount of said first emulsion of styrene-butadiene latex can be extended. carboxylic in the ink, in relation to the quantities of the second and third non-carboxylic styrene-butadiene latex emulsions present therein. Alternatively and preferably, the erasability of the ink 101 can be extended by including in it an antioxidant, such as tocopherol (vitamin E). The time extension effect of tocopherol can be further enhanced by the addition of vitamin C to the ink 101. This can be achieved through the use of liquid Oxynex® K, an antioxidant preparation commercially available from E. Merck (Germany) , which includes a tocopherol (which constitutes approximately 30%, by weight, of the preparation) and vitamin C (which constitutes approximately 6%, by weight, of the preparation). Preferably, the Oxynex® K is added to the present compound in an amount constituting between 0.1 and 0.7%, preferably 0.15%, by weight, of the ink 101. Preferably, the ink 101 further includes a slip stabilizing agent. soft, which is added to the compound to prevent coagulation of the discontinuous rubber phase under conditions of high sliding stress, such as, for example, during the formulation (ie, mixing) of the compound or during the application of the compound to a substrate of marking. The stabilizing agent of the soft slip is preferably a fatty acid salt. Potassium oleate is a particularly preferred slip stabilizing agent and will preferably be present in the ink 101 in an amount constituting between 0.2 and 1.5%, by dry weight, of the dry weight of the styrene-butadiene-non-carboxylic copolymer of the Latex emulsion mixture. Most preferably, potassium oleate constitutes approximately 0.6% by weight of ink 101. Another example of a soft slip stabilizing agent is Modicol® S, a sulphated fatty acid, commercially available from Henkel Corporation, Ambler, Philadelphia. Preferably, the ink 101 further includes a pH adjusting agent, which is used to modify the pH of the compound to achieve a pH of between 9 and 10. Preferably the adjuster agent of the pll is triethanolamine (TEA), which it is present in an amount that constitutes approximately between 0.5 and 1.5% (preferably about 1.0%), by weight, of the ink 101. Preferably, the ink 101 further includes an anti-seizing agent. Preferably, said antisecretory agent includes one or more water-soluble organic ketones, esters and alcohols that do not have a significant deleterious effect on the compound or its properties and whose boiling point is relatively high; for example, between about 140 and 300 ° C. Suitable anti-drying agents include sorbitol (preferably of a variety that does not crystallize), glycerin, urea or a mixture thereof. Preferably, the anti-seizure agent includes a 1: 1, 2: 1 or 3: 1 mixture of sorbitol and glycerin, respectively. In particular, a 3: 1 mixture of sorbitol and glycerin is preferred and said 3: 1 mixture constitutes between 3 and 15%, preferably about 7%, by weight of the ink 101. Preferably, the ink 101 further includes a anticorrosive agent. Preferably, said anti-corrosive agent benzotriazole and / or EDTA, present in a total amount constituting approximately between 0.2 and 0.5% (preferably about 0.2%), by weight of the ink 101. The ink 101 may also include an emulsion of alkyl acrylate copolymer which is used to improve the writing softness of the ink. The best results are obtained when such an acrylic alkyl copolymer emulsion, if used, is added to the non-carboxylic styrene-butadiene latex emulsion mixtures of the type not containing BUTONAL® NS 104. The following Examples are included herein merely for the purpose of illustrating various formulations of ink 101. In no way should these Examples be construed as limiting.

EXAMPLE 1 Weight% by weight PLIOLITE® 2108 40.0 BUTOFAN® NS 103 15.0 BUTANOL® NS 104 15.0 3% Laponite® / 40% glycerin / 57% water 7.0 3: 1 Sorbitol / glycerin 7.0 Triethanolamine 1.0 Oxynex® K liquid 0.15 Oleate of potassium 0.5 Black 4343 2.0 Deionized water 12.35 Compound pH 9.58 Compound viscosity (measured at 20 ° C using a rotating viscometer in which a tapered cone rotates at a fixed speed to give a sliding effort index of 0.2 reciprocal seconds) 74.7 cps EXAMPLE 2 Ingredient% by weight PLIOLITE® 2108 40.0 BUTOFAN® NS 103 15.0 BUTANOL® NS 104 15.0 3% Laponite® / 40% glycerin / 57% water 7.0 3: 1 Sorbitol / glycerin 7.0 Triethanolamine 1.0 Oxynex® K liquid 0.15 Oleate of potassium 0.5 Black B-PI Unisperso 2.0 Deionized water 12.35 Compound pH 9.65 Compound viscosity (measured at 20 ° C using a rotating viscometer in which a tapered cone rotates at a fixed speed to give a sliding effort index of 0.2 reciprocal seconds) 52.7 cps EXAMPLE 3 Ingredient% by weight PLIOL1TE® 2108 40.0 BUTOFAN® NS 103 15.0 BUTANOL® NS 104 15.0 3% Laponite® / 40% glycerin / 57% water 7.0 3: 1 Sorbitol / glycerin 7.0 Triethanolamine 0.5 Oxynex® K liquid 0.15 Oleate of potassium 0.5 Black 4343 2.0 Deionized water 12.85 pH of compound 9.43 compound viscosity (measured at 20 ° C using a rotating viscometer in which a tapered cone rotates at a fixed speed to give a sliding force index of 0.2 reciprocal seconds) 92.6 cps EXAMPLE 4 Ingredient% by weight PLIOLITE® 2108 45.0 BUTANOL® NS 104 25.0 3% Laponite® / 40% glycerin / 57% water 7.0 3: 1 Sorbitol / glycerin 7.0 Triethanolamine 1.0 Oxynex® K liquid 0.15 Oleate of potassium 0.5 Black 4343 2.0 Deionized water 12.35 Compound pH ... 9.66 compound viscosity (measured at 20 ° C using a rotating viscometer in which a tapered cone rotates at a fixed speed to give a sliding force index of 0.2 reciprocal seconds) 77.4 cps EXAMPLE 5 Ingredient% by weight PLIOLITE® 3757 40.0 BUTOFAN® NS 103 20.0 BUTANOL® NS 104 10.0 3% Laponite® / 40% glycerin / 57% water 7.0 3: 1 Sorbitol / glycerin 7.0 Triethanolamine 1.0 Oxynex® K liquid 0.15 Potassium oleate 0.6 Benzotriazole 0.15 Black 4343 2.0 Residual deionized water up to 100% The embodiments of the present invention described above are intended to be merely examples and those skilled in the art will be able to make numerous variations and modifications without departing from the spirit of the present invention. It is intended that such variations and modifications be within the scope of the present invention, as defined in the appended claims.

Claims (35)

WHAT IS REVINDED IS:

1. An ink that is erasable from porous and non-porous substrates by substantially non-abrasive mechanical means, said ink includes: (a) a latex emulsion mixture that includes a first non-carboxylic styrene-butadiene latex emulsion and a second latex emulsion of non-carboxylic styrene-butadiene; said latex emulsion mixture is characterized by being capable of being transformed, after being contacted with the surface of a porous marking substrate, from a first state in which said latex emulsion mixture is stable, to a second state in to which said latex emulsion mixture is unstable and wherein the styrene-butadiene phase rapidly agglomerates to form a cohesive film which is deposited directly on the surface of the porous marking substrate with little adhesion thereto; (b) a dye dispersed in the latex emulsion mixture: said dye is characterized by being associated with the adherent rubber phase film when said latex emulsion mixture is transformed to the second mentioned state; and (c) a smooth gliding agent and viscosity adjustment.

2. The ink as claimed in claim 1, wherein said smooth gliding and viscosity adjusting agent includes an inorganic clay material.

3. The ink as claimed in claim 2, wherein said smooth gliding and viscosity adjusting agent includes a synthetic smectic clay of sodium silicate lithium magnesium hydrate.

4. The ink as claimed in claim 3, wherein said smooth gliding and viscosity adjusting agent includes a 3% solution, by weight, of a synthetic smectic clay of sodium silicate lithium magnesium hydrated in 57%, by weight, of water and 40%, by weight, of glycerin.

The ink as claimed in claim 4, wherein said smooth gliding and viscosity adjusting agent constitutes approximately between 3 and 10%, by weight, of the ink.

The ink as claimed in claim 5, wherein said smooth gliding and viscosity adjusting agent constitutes approximately 7%, by weight, of the ink.

The ink as claimed in claim 1, wherein the ink has a viscosity of between 30 and 300 cps when measured at 20 ° C using a rotating viscometer in which a tapered cone rotates at a fixed speed to give a slide effort index of 0.2 reciprocal seconds.

8. The ink as claimed in claim 1, wherein said dye is a water-insoluble or water-dispersible pigment that is also oleophilic.

The ink as claimed in claim 1, wherein said dye constitutes between 2 and 5%, by weight, of the ink.

10. The ink as claimed in claim 1, wherein said latex emulsion mixture includes a first non-carboxylic styrene-butadiene latex emulsion containing approximately 40% solids total by weight and when at 25 °.

C has a Brookfield viscosity of about 30 cps, a pH of about 10.5-11.7, a Mooney value of about 150-160, a surface tension of about 55-65 dynes / cm, a particle size of about 650 Angstroms and a combined styrene content of approximately 21-29% and a second non-carboxylic styrene-butadiene latex emulsion containing approximately 70% total solids by weight and when at 25 ° C it has a Brookfield viscosity of approximately 1,200 cps , a pH of about 10.0-10.5, a Mooney value of about 70-75, a surface tension of about 32-36 dynes / cm and a combined styrene content of about 22-26% The ink as claimed in claim 10, wherein said first non-carboxylic styrene-butadiene latex emulsion constitutes approximately between 45 and 50%, by weight, of the ink, and said second non-carboxylic styrene-butadiene latex emulsion constitutes approximately 20 to 25%, by weight, of the ink, constituting, as a whole, said first and second styrene-latex emulsions. non-carboxylic butadiene, approximately 70%, by weight, of the ink.

12. The ink as claimed in claim 1, wherein said latex emulsion mixture includes a first emulsion of non-carboxylated ateiron-butadiene latex containing approximately 40% solids total by weight and which when added to 25 ° C has a Brookfield viscosity of about 30 cps, a pH of about 10.5-11.7, a Mooney value of about 150-160, a surface tension of about 55-65 dynes / cm, a particle size of about 650 Angstroms and a combined styrene content of about 21-29%, a second non-carboxylic styrene-butadiene latex emulsion containing approximately 70% solids by weight total and which when at 25 ° C has a Brookfield viscosity of about 1,200 cps, a pH of about 10.0-10.5, a Mooney value of about 70-75, a surface tension of about 32-36 dynes / cm, and a combined styrene content of about 22-26% and a third emulsion of non-carboxylic styrene-butadiene latex containing approximately 47% solids by weight and having a Brookfield viscosity of approximately 200 cps at a pH of 25 ° C, a pH of about 9.5-10.0, a Mooney value of about 70-75, a surface tension of about 60-65 dynes / cm, a particle size of about 640-720 Angstroms and a combined styrene content of about 22-26%.

The ink as claimed in claim 1, wherein said first non-carboxylic styrene-butadiene latex emulsion constitutes approximately 30-50%, by weight, of the ink, said second emulsion of styrene-butadiene latex. non-carboxylic acid constitutes approximately 5 to 20%, by weight, of the ink and said third non-carboxylic styrene-butadiene latex emulsion constitutes approximately 10 to 30%, by weight, of the ink; said first, second and third non-carboxylic styrene-butadiene latex emulsions constitute, overall, about 70%, by weight, of the ink.

14. The ink as claimed in claim 13, wherein said first non-carboxylic styrene-butadiene latex emulsion constitutes approximately 40%, by weight, of the ink, said second non-carboxylic styrene-butadiene latex emulsion constitutes approximately 10% by weight of the ink. %, by weight, of the ink and said third non-carboxylic styrene-butadiene latex emulsion constitutes approximately 20%, by weight, of the ink.

15. The ink as claimed in claim 1, which includes a first non-carboxylic styrene-butadiene latex emulsion containing approximately 40% total solids by weight and which when at 25 ° C has a Brookfield viscosity of about 30 cps, a pH of about 10.5-11.7, a Mooney value of about 150-160, a surface tension of about 55-65 dynes / cm, a particle size of about 650 Angstroms and a combined styrene content of about 21-29% and a third non-carboxylic styrene-butadiene latex emulsion containing approximately 47% solids by weight total and which when at 25 ° C has a Brookfield viscosity of about 200 cps, a pH of about 9.5 -10.0, a Mooney value of about 70-75, a surface tension of about 60-65 dynes / cm, a particle size of about 640-720 Angstroms and a styrene content c ombinado of approximately 22-26%.

16. The ink as claimed in claim 1, further including an antioxidant.

17. The ink as claimed in claim 16, wherein said antioxidant includes a tocopherol.

The ink as claimed in claim 16, wherein said antioxidant includes a preparation containing about 30%, by weight, of tocopherol and about 6%, by weight, of vitamin C.

19. The ink as claimed in claim 18, wherein said antioxidant constitutes approximately between 0.1 and 0.7%, by weight, of the ink.

The ink as claimed in claim 19, wherein said antioxidant constitutes approximately 0.15%, by weight, of the ink.

21. The ink as claimed in claim 1, further including a stabilizing agent for smooth sliding, to prevent coagulation of the discontinuous rubber phase under conditions of high sliding stress.

22. The ink as claimed in claim 21, wherein said soft slip stabilizing agent includes a fatty acid salt.

23. The ink as claimed in claim 22, wherein said soft gliding stabilizing agent is potassium oleate.

24. The ink as claimed in claim 23, wherein said soft slip stabilizing agent constitutes approximately

0. 2 and 1.5%, by dry weight, of the dry weight of the styrene-butadiene-non-carboxylic copolymer of the latex emulsion mixture.

25. The ink as claimed in claim 23, wherein said soft gliding stabilizing agent constitutes approximately 0.5%, by weight, of the ink.

26. The ink as claimed in claim 1, further including a pH adjusting agent for modifying the pH of the compound to achieve a pH of between 9 and 10.

27. The ink as claimed in claim 26, in which said pH adjusting agent is triethanolamine.

The ink as claimed in claim 29, wherein the triethanolamine is present in an amount constituting approximately between 0.5 and 1.0%, by weight, of the ink.

29. The ink as claimed in claim 1, further including an anti-seizing agent.

30. The ink as claimed in claim 29, wherein said anti-seizing agent includes a mixture of sorbitol and glycerin.

31. The ink as claimed in claim 29, wherein said anti-seizure agent includes a 3: 1 mixture of sorbitol and glycerin, respectively.

32. The ink as claimed in claim 31, wherein said antisecrent agent constitutes approximately 3 to 15%, by weight, of the ink.

33. The ink as claimed in claim 32, wherein said anti-seizing agent constitutes approximately 7%, by weight, of the ink.

34. The ink as claimed in claim 1, further including an emulsion of alkyl acrylate copolymer.

35. The ink as claimed in claim 1, further including an anticorrosive agent. Abstract An erasable ink, water based, smooth glide and a pen that contains it. In a preferred embodiment, the ink includes a mixture of three different aqueous non-carboxylic styrene-butadiene emulsions, a water-insoluble or water-dispersible pigment and a smooth gliding agent and viscosity adjustment in the form of a silicate clay. The ink further comprises an antioxidant preparation including tocopherol and vitamin C, to extend the time during which the ink remains erasable after it has been applied to a substrate, a mild slip stabilizing agent in the form of potassium oleate, to avoid the undesirable coagulation of the styrene-butadiene copolymer due to the sliding stress, a pH adjusting agent, in the form of triethanolamine, to modify the pH of the compound to reach a pH of between 9 and 10 and an anti-seizing agent in the form of a mixture 3: 1 of sorbitol and glycerin, respectively, the pen includes a barrel (13) to store a certain amount of ink; the barrel is made of polypropylene and has the upper end open (15); a hollow tip (29) made of stainless steel, a nickel-silver alloy or polyoxymethylene, with an upper end (31) and a lower end (33); said upper end is formed to constitute a bushing for a ball (35), a ball (41) that rotates and is housed in said bushing (35), made of sintered ceramic material, and an elongated hollow connector (21) manufactured with polyoxymethylene having the upper end open (23) and adapted to receive the lower end of said hollow tip and the lower end (25) open and adapted to receive the open upper end (15) of the barrel. The pellet (41) has a diameter of about 0.7 mm or greater. The bushing (35) has a maximum interior width that exceeds the diameter of the ball (41) by approximately 0.015-0.025 mm and is shaped to allow the ball (41) to move axially within the bushing a distance of approximately 0.03-0.07 mm.