MXPA97005830A - Correction fluid that does not affect ozone, with improved over-script features - Google Patents

Abstract

In general, the invention relates to a correction fluid that does not affect the ozone, which has improved overwriting characteristics. Correction fluids that do not affect ozone thus have a key benefit (good overwriting characteristics) associated with halogenated hydrocarbon solvent-based correction fluids, but they also have environmental benefits associated with solvent-based correction fluids. It does not affect ozone. Specifically, the present invention relates to a correction fluid that does not affect the ozone, comprising a non-halogenated hydrocarbon solvent, a polymer phase and an opacifying phase, wherein the ratio of the opacifying phase to the polymer phase is from 2.2. up to about 3.8, preferably from about 2.4 to about 3.6 (based on the weight

Description

CORRECTION FLUID THAT DOES NOT AFFECT OZONE WITH IMPROVED OVER-WRITING FEATURES FIELD OF THE INVENTION The invention relates to correction fluids. Correction fluids are used for the correction of handwritten marks, typewriting, photocopying or laser printing on paper. In general, the correction fluids are applied to a paper surface on an erroneous mark in liquid form. The fluid subsequently forms a film that effectively covers the erroneous marks on the surface and can receive a correct mark. Making a corrective mark on the film is commonly known as "overwriting". BACKGROUND OF THE INVENTION Correction fluids typically include some standard ingredients, which include an opacifying pigment (commonly titanium dioxide), a polymeric material that forms a film, and a solvent. The opacifying pigment is dispersed in the fluid and provides the basic white color that can be colored with other pigments to provide a correction fluid that corresponds very closely to the color of the paper to which the fluid is to be applied. The opacifying pigment works to obscure the erroneous marks on which the correction fluid is applied. The film-forming polymeric material, also known as the binder, binds the pigment to the paper and helps form a flexible but continuous coating that remains once the solvent has dried. The solvent is used as the carrier for the other ingredients in the fluid. Historically, halogenated hydrocarbons have been the solvents of choice for the compositions of the correction fluids. Halogenated hydrocarbon solvents present special advantages mainly because they have evaporation rates that provide correction fluids that dry quickly and completely. Also, they do not interact with the typing marks to cause an unacceptable stain. Also, they can effectively dissolve those polymeric film-forming materials that provide durable but flexible films without causing excessive clogging or distortion of the paper surface. Despite their recognized advantages, when used as correction fluid solvents, the use of halogenated hydrocarbon solvents has become a matter of increased concern, mainly due to their adverse effect on the environment (decrease in stratospheric ozone). Accordingly, providing a correction fluid that does not affect the ozone or "ozone-friendly" by eliminating the use of halogenated hydrocarbon solvents has become somewhat desirable. For correction fluid that does not affect ozone, a correction fluid is defined that either does not contain a material that migrates into the stratosphere or, if it contains such material, the material does not cause a reduction in ozone concentrations. Attempts have been made to replace the halogenated solvents with non-halogenated alternatives. Water-based systems such as those described in U.S. Patent No. 5,332,599 are not effective for a wide variety of ink formulations. Alternatively, non-halogenated hydrocarbon solvents, such as those described in U.S. Patent Nos. 5,199,976 and 5,306,755 cover a wide range of ink types but suffer from poor overwriting characteristics. It is an object of the present invention to provide a correction fluid based on a non-halogenated solvent system with improved overwrite characteristics. DESCRIPTION OF THE INVENTION In general, the invention relates to a correction fluid that does not affect ozone, which has improved overwriting characteristics. Thus, correction fluids that do not affect ozone have a key benefit (good overwriting characteristics) associated with solvent-based correction fluids of halogenated hydrocarbons, but they also have the environmental benefits associated with solvent-based correction fluids that do not affect ozon_. Specifically, the present invention relates to a correction fluid that does not affect the ozone, comprising a non-halogenated hydrocarbon solvent, a polymer phase and an opacifying phase, wherein the ratio of the opacifying phase to the polymer phase is from about 2.2 to about 3.8, preferably from about 2.4 to about 3.6 (based on weight). Other features and advantages of the invention will be apparent from the description of the preferred embodiments thereof, and from the claims.

As used herein, the term "overwriting characteristics" refers to the ability of correction fluid films to accept new written matter in the form of inks, marker pens, and typing impacts. Without joining the theory, the applicants believe that this feature is related to film strength and paper adhesion. When correction fluid films exhibit weak strength and poor adhesion to paper, the overwriting characteristic is extremely poor. This typically results in grooves and flaking of the correction fluid while new feather marks are made on the film. Accordingly, correction fluids exhibiting good "overwriting characteristics" do not exhibit excessive flaking or chipping during normal writing pressures. The importance of a good overwriting feature is very important with ink pens and typing overwrites due to the relatively high pressures applied. The importance of a good overwriting feature with marker pens is typically less important.

According to the present invention, it has been found that by making a proportioning of the opacifying phase with the polymer phase of a correction fluid based on a non-halogenated hydrocarbon solvent, it is possible to obtain dramatically improved overwriting characteristics. As used herein, the term "opacifying phase" refers to the total amount of opacifying agent found in the correction fluid. Suitable opacifying agents for use in the present invention include titanium and rutile dioxide, titanium dioxide and anatase, zinc sulfide, zinc oxide, calcium carbonate or mixtures of these materials, commercially available. Preferably, the opacifying agent has an average particle size between about 0.2 and about 0.4 microns and an average oil absorption of about 14 pounds of oil / 100 pounds of pigment to about 36 pounds per 100 pounds. The amount of opacifying agent may vary depending on the degree of coverage desired (low amounts will provide a poor coverage while higher amounts will provide an extremely opaque coverage). From about 32 to about 55% by weight of the opacifying agent based on the total weight of the composition is generally adequate. Preferably, the opacifying agent is selected from the group consisting of titanium and rutile dioxide and titanium dioxide anatase at levels from about 38 to about 52% by weight based on the total weight of the composition. As used herein, the "polymer phase" refers to the binder that forms the film (i.e., resin), plasticizers and dispersants. Suitable binders for use in the present invention include butyl methacrylate (MAB) thermoplastic copolymers (such as Neocryl B 705 or Neocryl B700 polymers manufactured by Zeneca Resins, Wilmington, MA or Rohagum P 675 supplied by Rohm Tech Inc., Malden, MA); vinyl toluene-butadiene copolymer (such as those manufactured by Goodyear Chemicals); isobutyl methacrylate polymer (PMIB) (Acryloid B67, manufactured by Rohm &Haas, Philadelphia, PA); n-butyl methacrylate polymer (such as Elvacite 2044 manufactured by DuPont Chemical, Wilmington, DE); n-butyl methacrylate / isobutyl methacrylate copolymer (such as Elvacite 2046 manufactured by DuPont Chemical) and mixtures thereof. Suitable "plasticizers" include ditridecyl phthalate. Suitable dispersants include sodium dioctyl sulfosuccinate and polymeric fatty esters (Hypermer LP1 manufactured by ICI Americas); and mixtures thereof. As used herein, "non-halogenated hydrocarbon solvents" include any alkylated cyclohexane or cyclohexane and aliphatic hydrocarbons containing 10 or fewer carbon atoms, Preferably the material is methylcyclohexane. Optionally, the correction fluids of the present invention may also include other typical correction fluid ingredients such as inking dyes, for example, carbon black, dark ocher, yellow oxide, etc. These inking dyes are counted as opacifying agents in the calculation of the "opacification phase". Also, a small amount of mustard oil (0.1-0.2%) is often added as an impediment. According to the present invention, an opacifying phase to polymer phase ratio in the range of 2.2 to 3.8 provides excellent overwriting characteristics when compared to the correction systems of the non-halogenated hydrocarbon solvents. Preferably, proportion of the opacification phase to the polymer phase is from 2.4 to 3.6.

EXAMPLES Examples 1-5 below illustrate fluids with the proportions of opacifying phase to the polymeric phase according to the present invention which provide good overwriting properties at a high wet fluid application, for example 5 mil film thicknesses ( thousandths of an inch). Example 6 below shows a proportion outside the claimed range. In use, the correction fluid of Example 6 shows inferior overwriting properties at high fluid applications. EXAMPLE 1 Ingredients% by weight 1. Methylcyclohexanone 41.41 2. MAIB thermoplastic copolymer Polymer Neocryl B 705 10.78 3. Ditridecyl phthalate 3.99 4. Polymeric fatty ester Hypermer LPl (ICI Americas, Inc.) 2.22 5. Titanium dioxide, Tipure R-931 41.39 6. Black smoke 0.07 7. Mustard oil 0.12 8. Fragrance 759292/0602185 (Haarmann &Rei er) 0.02 Opacifying phase to polymeric phase ratio: 2.44 EXAMPLE 2 Ingredients% by weight 1. Methylcyclohexanone 42.30 2. Copolymer MAIB Thermoplastic Polymer Neocryl B 705 9.65 3. Ditridecyl phthalate 3.57 4. Polymeric fatty ester Hypermer LPl (ICI Americas, Inc.) 1.98 . Titanium dioxide, Tipure R-931 42.29 6. Black smoke 0.07 7. Mustard oil 0.12 8. Fragrance 759292/0602185 (Haarmann &Reimer) 0.02 100.00 Opacifying phase to polymer phase ratio: 2.78 EXAMPLE 3 Ingredients% by weight 1. Methylcyclohexanone 40.17 2. Copolymer MAIB Thermoplastic Polymer Neocryl B 705 9.16 3. Ditridecyl phthalate 3.39 4. Polymeric fatty ester Hypermer LPl (ICI Americas, Inc.) 1.88 . Titanium dioxide, Tipure R-931 45.19 6. Carbon black 0.08 7. Mustard oil 0.11 8. Fragrance 759292/0602185 (Haarmann &Reimer) 0.02 100.00 Ratio of pigment to binder: 3.13 EXAMPLE 4 Ingredients% by weight 1. Methylcyclohexanone 39.69 2. Copolymer MAIB Thermoplastic Polymer Neocryl B 705 8.52 3. Ditridecyl phthalate 3.15 4. Polymeric fatty ester Hypermer LPl (ICI Americas, Inc.) 1.75 5. Titanium dioxide, Tipure R-931 46.68 6. Black smoke 0.08 7. Mustard oil 0.11 8. Fragrance 759292/0602185 (Haarmann &Reimer) 0.02 100.00 Opacifying phase to polymer phase ratio: 3.4¡ EXAMPLE 5 Ingredients% by weight 1. Methylcyclohexanone 46.21 2. Copolymer vini 1 toluene-butadiene (Goodyear Chemicals) 9.68 3. Ditridecyl phthalate 2.64 4. Polymeric fatty ester Hypermer LPl (ICI Americas, Inc.) 1.65 . Titanium dioxide, Tipure R-931 39.60 6. Black smoke 0.07 7. Mustard oil 0.13 8. Fragrance 759292/0602185 (Haarmann &Reimer) 0.02 100.00 Opacifying phase to polymer phase ratio: 2.83 EXAMPLE 6 Ingredients% by weight 1. Methylcyclohexanone 48.91 2. Vinyl toluene-butadiene copolymer (Goodyear Chemicals) 8.53 3. Dioctyl Sulfoccinate Sodium 1.56 4. Titanium dioxide, Tipure R-931 40.79 5. Black smoke 0.07 6. Mustard oil 0.14 100.00 Opacifying phase to polymer phase ratio: 4.04 The correction fluids containing the above ingredients were prepared by first dissolving the binder in the solvent system. Next, the dispersant, the plasticizer and the opacifying agent were added and the mixture was dispersed for 3 hours in a bead mill after the carbon black and mustard oil were added to obtain the final fluid composition. Other embodiments are within the claims. For example, in addition to the most preferred ingredients, the composition may also include various additives known to those skilled in the art. These additives are incorporated to improve specific properties. These include flattening agents to control film gloss, flow additives and thickeners to control brush application, leveling and settling and pigment extenders to reduce costs.

Claims (1)

1. CLAIMS A correction fluid that does not affect the ozone, characterized in that it comprises: a non-halogenated hydrocarbon solvent; a polymer phase and an opacifying phase, wherein the ratio of the opacifying phase to the polymer phase is from 2.2 to 3.8 based on weight. A correction fluid according to claim 1, characterized in that the solvent is selected from the group consisting of: cyclohexane; an alkylated cyclohexane; an aliphatic hydrocarbon containing 10 or fewer carbon atoms; or mixtures thereof. A correction fluid according to claim 2, characterized in that the opacifying phase consists of a material selected from the group consisting of titanium and rutile dioxide, titanium dioxide and anatase, zinc sulphide, zinc oxide, calcium carbonate or mixtures of these materials. A correction fluid according to claim 3, characterized in that the polymer phase is comprised of a resin material selected from the group consisting of thermoplastic butyl methacrylate, vinyl toluene-butadiene copolymer, isobutyl methacrylate polymer, n-butyl copolymer methacrylate / isobutyl methacrylate and mixtures thereof. A correction fluid according to claim 4, characterized in that the polymer phase further comprises a ditridecyl phthalate plasticizer. A correction fluid according to claim 5, characterized in that the polymer phase further comprises a dispersant selected from the group consisting of sodium dioctyl sulfoccinate, polymeric fatty ester and mixtures thereof. A correction fluid according to claim 6, characterized in that the proportion of the pigment to the binder is in the range of 2.4 to 3.6.