US3922390A

US3922390A - Method for improving the readability during optical scanning of automatic car identification labels

Info

Publication number: US3922390A
Application number: US510891A
Authority: US
Inventors: Joseph V Otrhalek; Robert E Gansser
Original assignee: BASF Wyandotte Corp
Current assignee: Diversey Wyandotte Corp; BASF Corp
Priority date: 1974-10-01
Filing date: 1974-10-01
Publication date: 1975-11-25
Anticipated expiration: 1992-11-25

Abstract

A method for improving the readability during optical scanning of automatic car identification labels by applying a continuous coat to the labels of a thickened acid cleaner comprising an aqueous hydrochloric acid, an organic acid, a nonionic surfactant, an anionic surfactant and water.

Description

United States Patent Otrhalek et al.

[451 Nov. 25, 1975 METHOD FOR IMPROVING THE READABILITY DURING OPTICAL SCANNING OF AUTOMATIC CAR IDENTIFICATION LABELS Inventors: Joseph V. Otrhalek, Dearborn;

Robert E. Gansser, Wyandotte, both of Mich.

BASF Wyandotte Corporation, Wyandotte, Mich.

Filed: Oct. 1, 1974 Appl. No.: 510,891

Assignee:

US. Cl. 427/162; 134/3; 134/40; 252/136; 252/142; 427/401 Int. Cl. B05D 5/06; BOSD 1/00; BOSD 3/00 Field of Search 134/3, 40; 252/136, 142; 427/162, 401

[56] References Cited UNITED STATES PATENTS 3,650,965 3/1972 Cantor et al..... 252/106 3,793,221 2/1974 Otrhaiek et a1 252/136 Primary ExaminerMichael R. Lusignan Attorney, Agent, or FirmNorbert M. Lisicki; Bernhard R. Swick; Robert E. Dunn 3 Claims, No Drawings METHOD FOR IMPROVING THE READABILITY DURING OPTICAL SCANNING OF AUTOMATIC CAR IDENTIFICATION LABELS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a method for improving the readability during optical scanning of automatic car identification labels by applying a thickened acid cleaner composition thereto. Automatic car identification labels are composed of retro-reflective plastic materials which are attached to railroad cars for purposes of checking the location of the cars in transit. Due to the large numbers of railroad cars employed by various corporations, a system of checking the location and number of railroad cars was developed. This system employs automatic scanning devices, in conjunction with computers, which optically scan a series of reflective tapes, of different colors, which are attached to the side of the railroad car. The computer then tabulates the ownership of the car and its location. This information may then be employed to apply the proper demurrage charges. It may also be employed to trace the movements of the car from the point of origin to its destination point. In order for the scanning devices to properly identify the car, it is, of course, necessary that the surface of the identification labels be sufficiently clean that the optical scanner can transmit the configuration and color of the labels to the computer.

2. Description of the Prior Art In the present state of the art the automatic car identification labels are cleaned by apray application to the railroad car of an alkaline or acid cleaner followed by hand brushing and rinsing. The cleaners used for this purpose must be vigorously and thoroughly brushed if adequate cleaning is to be obtained.

The use of acid in cleaning compositions is known. For instance, U.S. Pat. No. 2,257,467 discloses a solidified acid composition for cleaning toilet bowls and the like wherein the composition consists of sodium silicate, water and hydrochloric acid. Another acid cleaner is disclosed in U.S. Pat. No. 3,271,319 wherein it is taught that stains can be removed from glass surfaces by the use of an acid cleaner consisting of water, hydrofluoric acid, a carboxymethylcellulose thickener and a small amount, usually less than 1 percent, of an alkyl sulfate or alkyl aryl sulfonate wetting agent. A still more recent patent, U.S. Pat. No. 3,622,391 teaches removing aluminide coatings from cobalt base or nickel base superalloys by the use of a hydrofluoric acid and water composition which permissibly includes a low foaming or nonfoaming wetting agent. It is further disclosed that the composition can be thickened by adding a condensation product of ethylene oxide with a molecular weight of 4,000 and gum tragacanth. However, the use of this composition requires a follow-up neutralization with an alkali solution followed by water rinsing.

Mineral acids have also been used in cleaning compositions as a defoamer. This technique is illustrated in U.S. Pat. No. 3,650,965 wherein the foaming qualities of nonionic surfactants for food industry cleaning can be reduced by the use of an organic acid coupled with a mineral acid such as phosphoric acid, the acid component being more than the surfactant component.

It has also been known to clean transportation equipment such as trains, boxcars and the like by the use of an acid cleaner to remove siliceous soils followed by an 2 alkaline cleaner to remove organic and oily soils then finally followed by water rinsing.

Two recently issued patents, U.S. Pat. No. 3,793,221 and 3,822,234 disclose the composition of the instant invention and its use in cleaning vehicles. These patents also teach the necessity for rinsing off the acid cleaner.

SUMMARY OF THE INVENTION In accordance with this invention there is provided a method for improving the readability during optical scanning of automatic car identification labels by applying thereon a coat of a thickened acid cleaner comprising:

I. an aqueous hydrochloric acid in an amount from about 15 to about 40 weight percent,

2. an organic acid selected from the group consisting of oxalic, tartaric, citric acid and mixtures thereof in an amount from about 1 to about 6 weight percent,

3. a nonionic surfactant in an amount from about 7 to about 23 weight percent,

4. an anionic surfactant in an amount from about 1 to about 7 weight percent, and

5. water in an amount from about 76 to about 24 weight percent;

all weight percents being based on the total composition, provided that the said nonionic surfactant and the said anionic surfactant when taken together constitute from about 10 to about 30 weight percent of said composition and said nonionic surfactant constitutes from about to about weight percent of the combined weight percent of nonionic and anionic surfactants.

This concentrate is used as is by application to the labels without any subsequent alkaline or aqueous rinsing. The cleaner is allowed to remain on the surface of the labels for a few minutes prior to optical scanning by the automatic scanning devices. It has been found that this thickened acid cleaner not only cleans the labels adequately without brushing but also that the cleaner need not be rinsed off after application. In fact, it has been found that the unrinsed, unbrushed cleaner tends to leave the surface of the labels brighter and easier to read by the optical scanner than if it were rinsed from the surface.

The effect of this invention is:

l. the labels are in a brighter condition and easier to read than when they are cleaned by conventional means,

2. there is no scratching or undue wearing of the reflective surface since brushing is not necessary, thus prolonging the life of the label, and

3. there is a saving of both time and labor since rinsing is not required in the cleaning process.

The ordinary cleaners presently employed if allowed to remain on the labels without rinsing present a dull surface which prevents the optical scanner from reading the labels properly.

The acid cleaner can also be used by dilution of up to 1 volume of cleaner with 3 volumes of water but preferably it is used in its concentrated form or at most a dilution of 1:1 by volume of cleaner to water.

DESCRIPTION OF THE PREFERRED EMBODIMENT The hydrochloric acid employed in this invention is that commercially available concentrated hydrochloric acid which has a concentration of 36 to 37 weight percent. It is within the scope of this invention to use as a partial replacement up to but no more than 50 percent by weight of hydrochloric acid, an equal weight amount of concentrated sulfuric acid or phosphoric acid. The sulfuric acid is considered to be that commercially available acid having a concentration of about 96 percent by we ght. The phosphoric acid, which is available commerc ally in different concentrations, for the purpose of this invention is considered to have a concen trat on of 75 percent by weight. Since the amount of water which is included in the cleaner concentrate varies from 24 to 76 percent, the hydrogen ion concentration of the mineral acids is not critical. Generally, the use of sulfuric acid and/or phosphoric acid is not favored except for economic reasons. On a weight percent basis the acid cleaner of this invention contains from about to about 40 weight percent and more preferably, the acid content will be from about to about 30 weight percent.

The second component of the composition is an organic acid preferably selected from the group consisting of oxalic, tartaric, citric acids or mixtures thereof in an amount from about 1 to about 6 weight percent and more preferably in an amount from about 2 to about 4 weight percent.

The particular surfactants employed in the invented composition in addition to having a cleaning effect also exhibit unusual thickening properties for this composition which were entirely unexpected. Therefore the surfactants of this invention are doubly critical. The non-ionic surfactant is present in an amount from ab ut 7 to ab ut 23 weight percent of the final composit on and more prefe a ly in an amount from about 12 to 18 w ight percent.

The non o c surface active age ts which are advant s ed-sly employed in the compositions of the invention are generally the polyoxyalkylene adducts of hydrophobic ba es wherein the oxygen/carbon atom ratio in the oxyalkylene portion of the molecule is grea er than 0.40. Those compositions which are condensed with hydrophobic bases to provide a polyoxya kylene portion having an oxygen/carbon atom ratio greater than 0.40 include ethylene oxide, butadiene dioxide and glycic ol, mixtures of these alkylene ox des with each other and with minor amounts of propylene oxide, butylene oxide, amylene oxide, styrene oxide, and other higher molecular weight alkylene ox des. Ethylene oxide, for example, is condensed with the hydrophobic base in an amount sufficient to impart water dispersibility or solubility and surface active properties to the molecule being prepared. The exact amount of ethylene oxide condensed with the hydrophobic base will depend upon the chemical characteristics of the base employed and is readily apparent to those of ordinary skill in the art relating to the synthesis of oxyalkylene surfactant condensates.

Typical hydrophobic bases which can be condensed with ethylene oxide in order to prepare nonionic surface active agents include monoand polyalkyl pheno s, polyoxypropylene condensed with a base having from about 1 to 6 carbon atoms and at least one reactive hydrogen atom, fatty acids, fatty amides and fatty alcohols. The hydrocarbon ethers such as the benzyl or lower alkyl ether of the polyoxyethylene surfactant condensates are also advantageously employed in the compositions of the invention.

Among the suitable nonionic surface active agents are the polyoxyethylene condensates of alkyl phenols having from about 6 to 20 carbon atoms in the alkyl 4 portion and from about 5 to 30 ethenoxy groups in the polyoxyethylene radical. The alkyl substituent on the aromatic nucleus may be octyl, diamyl, n-dodecyl, polymerized propylene such as propylene tetramer and trimer, isoctyl, nonyl, etc. The benzyl ethers of the polyoxyethylene condensates of monoalkyl phenols impart good properties to'the compositions of the invention and a typical product corresponds to the formula:

Higher polyalkyl oxyethylated phenols corresponding to the formula:

wherein R is hydrogen or an alkyl radical having from about 1 to 12 carbon atoms, R and R are alkyl radicals having from about 6 to 16 carbon atoms and n has a value from about 5 to 30 are also suitable as nonionic surface active agents. A typical oxyethylated polyalkyl phenol is dinonyl phenol condensed with 14 moles of ethylene oxide.

Other suitable nonionic surface active agents are cogeneric mixtures of conjugated polyoxyalkylene compounds containing in their structure at least one hydrophobic oxyalkylene chain in which the oxygen/carbon atom ratio does not exceed 0.40 and at least one hydrophilic oxyalkylene chain in which the oxygen/carbon atom ratio is greater than 0.40.

Polymers of oxyalkylene groups obtained from propylene oxide, butylene oxide, amylene oxide, styrene oxide, mixtures of such oxyalkylene groups with each other and with minor amounts of polyoxyalkylene groups obtained from ethylene oxide, butadiene dioxide, and glycidol are illustrative of hydrophobic oxyalkylene chains having an oxygen/carbon atom ratio not exceeding 0.40. Polymers of oxyalkylene groups obtained from ethylene oxide, butadiene dioxide, glycidol, mixtures of such oxyalkylene groups with each other and with minor amounts of oxyalkylene groups obtained from propylene oxide, butylene oxide, amylene oxide and styrene oxide are illustrative of hydrophilic oxyalkylene chains having an oxygen/carbon atom ratio greater than 0.40.

Further suitable nonionic surface active agents are the polyoxyethylene esters of higher fatty acids having from about 8 to 22 carbon atoms in the acyl group and from about 5 to 30 ethenoxy units in the oxyethylene portion. Typical products are the polyoxyethylene adducts of tall oil, rosin acids, lauric, stearic and oleic acids and the like. Additional nonionic surface active agents are the polyoxyethylene condensates of higher fatty acid amines and amides having from about 8 to 22 carbon atoms in the fatty alkyl or acyl group and about 10 to 30 ethenoxy units in the oxyethylene portion. [1- lustrative products are coconut oil fatty acid amides condensed with about 5 to 30 moles of ethylene oxide.

Other suitable polyoxyallcylene nonionic surface active agents are the alkylene oxide adducts of higher aliphatic'alcohols and thioalcohols having from about 8 to 22 carbon atoms in the aliphatic portion and about to 30 oxyalkylene portiomTypical products are: (l) synthetic fatty alcohols, such asn-decyl, 'n-undecyl, ndodecyl, n-tridecyl, n-tetradecyl, n-hex'a'decyl, noctadecyl and mixtures thereofcondensed with 5 to 30 moles of ethylene oxide; (2) a mixture of normal fatty alcohols condensed with 8 to 20 moles of ethylene oxide and capped with benzyl halide or an alkyl halide, (3) a mixture of normal fatty alcohols condensed with 5 to 30 moles of a mixture of ethylene and propylene oxides, (4),-a mixture of several fatty alcohols condensed sequentially with 2 to 20 moles of ethylene oxide and 3 to moles of propylene oxide, in either order, (5) a mixture of normal fatty alcohols condensed with a mixture of propylene and ethylene oxides, in which the oxygen/carbon atom ratio is less than 0.40 followed by a mixture of propylene and ethylene oxides in which the oxygen/carbon atom ratio is greater than 0.40 or a linear secondary alcohol condensed with 3 to 30 moles of ethylene oxide, (6) a linear secondary alcohol condensed with a mixture of propylene and ethylene oxides, (7) a linear secondary alcohol condensed with a mixture of ethylene, propylene, and higher alkylene oxides.

Of the foregoing described nonionic surface active agents or surfactants, a particularly preferred group is the polyethylene oxide condensates of alkyl phenols, particularly those having an alkyl group containing from about 6 to 12 carbon atoms in either a straight chain or branch chain configuration with ethylene oxide, the ethylene oxide being present in amounts equal to 5 to 25 moles of ethylene oxide per mole of alkyl phenol. This group of surfactants is exemplified by octylphenoxy polyethoxyethanol.

The second component of the surfactant system of this invented composition is an anionic surfactant which is present in an amount from about 1 to about 7 weight percent and more preferably in an amount from about 2 to about 3 percent.

Anionic synthetic non-soap detergents can be broadly described as organic sulfuric and sulfonic acid reaction products having in their molecular structure an alkyl radical containing from about 8 to about 22 carbon atoms and a radical selected from the group consisting of sulfonic acid and sulfuric acid ester radicals. (Included in the term alkyl is the alkyl portion of higher acyl radicals.) Important examples of the synthetic detergents which from a part of the preferred compositions of the present invention are: (1) those obtained by sulfating the higher alcohols (Cg-C 3 carbon atoms) produced by reducing the glycerides of tallow or coconut oil, (2) alkyl benzene sulfonates, in which the alkyl group contains from about 9 to about carbon atoms, including those of the types described in US. Pat. Nos. 2,220,099 and 2,477,383 (the alkyl radical can be a straight or branched aliphatic chain), (3) alkyl glyceryl ether sulfonates, especially those ethers of the higher alcohols derived from tallow and coconut oil, (4) coconut oil fatty acid monoglyceride sulfates and sulfonates, (5) sulfuric acid esters of the reaction product of one mole of a higher fatty alcohol (e.g., tallow or coconut oil alcohols) and about 1 to 6 moles of ethylene oxide, (6) sulfuric acid and sulfonic acid esters of the reaction product of one mole of a higher fatty oil (e.g., coconut or castor oil) and about 1 to 6 moles of ethylene oxide, (7) alkyl phenolethylene oxide ether sulfate with about 1 to about 10 units of ethylene oxide per molecule and in which the alkyl radicals contain from 8 to about 12 carbon atoms, (8) the reaction product of fatty acids esterified with isethionic acid where, for example, the fatty acids are derived from coconut oil, (9) fatty acid amide of a methyl tauride in which the fatty acids, for example, are derived from coconut oil; and others known in the art, a number being specifically set forth in U.S. Pat. Nos. 2,486,921, 2,486,922 and 2,396,278. While less preferred the sodium and potassium salts of the foregoing sulfonic and sulfuric acid and/or ester anionic surfactants can also be used. The foregoing anionic surfactants are further exemplified in McCutcheons Detergents & Emulsifiers, 1972 Annual, Allured Publishing Corporation, Ridgewood, New Jersey.

Particularly suited for the process and composition of this invention are the alkyl or aryl sulfonic acid anionic surfactants exemplified by a linear alkyl benzene sulfonic acid.

When taken together in considering the foregoing nonionic and anionic surfactants, it is critical to the success of this invention that the total amount of surfactant present constitute from about 10 to about 30 weight percent of the total cleaner composition and that the non-ionic portion of the total surfactant portion be from about to about weight percent.

The final component of the invented cleaning composition is water which is present in an amount from about 76 to about 24 percent by weight and preferably in an amount from about 74 to about 45 weight percent.

In addition to the foregoing ingredients, as is well known in the detergent art, dyes, perfumes, corrosion inhibitors and the like may be added to the cleaning composition.

The compositions of this invention are prepared by mixing techniques well known to those skilled in the art. A convenient procedure for the preparation of the composition at room temperature would be to charge the water to the vessel, add in the organic acids followed by the nonionic surfactant and the anionic surfactant and finally the hydrochloric acid. If it is desirable to add other optional modifiers to the composition such as dyes, perfumes, and inhibitors, they can be added as convenient during the preparation of the composition.

As mentioned above, the composition of this invention has been disclosed in US. Pat. No. 3,793,22l which disclosure is hereby included by reference.

The acid cleaner concentrate is flowed onto the identification label in an amount such that a thin, continuous film covering the label is obtained. Within a few minutes the labels are clean and shiny. In order to obtain best results the acid cleaner is not rinsed off.

The practice of this invention is illustrated but not limited by the examples given below. Unless otherwise noted all parts or percents are by weight.

EXAMPLE 1 An open mixing vessel was charged with 54 parts of water and 3 parts of oxalic acid dihydrate was dissolved therein. Octylphenoxy polyethoxyethanol, 14 parts, was added next, followed by 2.5 parts of a linear alkyl benzene sulfonic acid. Finally 26.5 parts of 37% hydrochloric acid were added. The thickened acid cleaner was then discharged from the mixing vessel.

The foregoing concentrate was sprayed onto the labels of 32 ore hopper railroad cars of a train moving at 4 mph. The labels were sufficiently dirty that none 7 could be read by the automatic optical scanning device. Approximately ten minutes after spraying, the train passed a scanner which correctly read 23 of the labels. After brushing and rinsing, the train again passed by a scanning station which read only 15 of the labels of which only 8 were correct.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

l. A method for improving during optical scanning, the readability of automatic car identification labels comprising a. applying a continuous coat of a thickened acid cleaner composition consisting essentially of 1. an aqueous hydrochloric acid in an amount from about 15 to about 40 weight percent,

3. a nonionic surfactant in an amount from about 7 to about 23 weight percent,

8 4. an anionic surfactant in an amount from about 1 to about 7 weight percent, and 5. water in an amount from about 76 to about 24 weight percent; all weight percents being based on the total composition, provided that the said nonionic surfactant and the said anionic surfactant when taken together constitute from about 10 to about 30 weight percent of said composition and said nonionic surfactant constitutes from about to about weight percent of the combined weight percent of nonionic and anionic surfactants,

b. allowing said coat to remain on said labels during said scanning.

2. The method of claim 1 wherein the acid cleaner composition is diluted with water up to a 1:3 volume ratio of cleaner to water prior to application of said diluted composition to the labels.

3. The method of claim 1 wherein the acid cleaner composition is diluted with water in a lzl volume ratio of cleaner to water prior to application of said diluted composition to the labels.

Claims

1. A METHOD FOR IMPROVING DURING OPTICAL SCANNING, THE READABILITY OF AUTOMATIC CAR IDENTIFICATION LABELS COMPRISING A. APPLYING A CONTINOUS COAT OF A THICKENED ACID CLEANER COMPOSITION CONSISTING ESSENTIALLY OF

1. AN AQUEOUS HYDROCHLORIC ACID IN AN AMOUNT FROM ABOUT 15 TO ABOUT 40 WEIGHT PERCENT,

2. AN ORGANIC ACID SELECTED FROM THE GROUP CONSISTING OF OXALIC, TATARIC, CITRIC ACID AND MIXTURES THEREOF IN AN AMOUNT FROM ABOUT 1 TO ABOUT 6 WEIGHT PERCENT,

3. The method of claim 1 wherein the acid cleaner composition is diluted with water in a 1:1 volume ratio of cleaner to water prior to application of said diluted composition to the labels.

3. a nonionic surfactant in an amount from about 7 to about 23 weight percent,

3. A NONIONIC SURFACTANT IN AN AMOUNT FROM ABOUT 7 TO ABOUT 23 WEIGHT PERCENT,

5. water in an amount from about 76 to about 24 weight percent; all weight percents being based on the total composition, provided that the said nonionic surfactant and the said anionic surfactant when taken together constitute from about 10 to about 30 weight percent of said composition and said nonionic surfactant constitutes from about 75 to about 90 weight percent of the combined weight percent of nonionic and anionic surfactants, b. allowing said coat to remain on said labels during said scanning.

5. WATER IN AN AMOUNT FROM ABOUT 76 TO A OUT 24 WEIGHT PERCENT; ALL WEIGHT PERCENTS BEING BASED ON THE TOTAL COMPOSITION, PROVIDED THAT THE SAID NONIONIC SURFACTANT AND THE SAID ANIONIC SURFACTANT WHEN TAKEN TOGETHER CONSITUTED FROM ABOUT 10 TO ABOUT 30 WEIGHT PERCENT OF SAID COMPOSITION AND SAID NONIONIC SURFACTANT CONSTITUTES FROM ABOUT 75 TO ABOUT 90 WEIGHT PERCENT OF THE COMBINED WEIGHT PERCENT OF NONIONIC AND ANIONIC SURFACTANTS. B. ALLOWING SAID COAT TO REMAIN ON SAID LABELS DURING SAID SCANNING.