US2950217A

US2950217A - Impregnation process

Info

Publication number: US2950217A
Application number: US621536A
Authority: US
Inventors: Lichtblau Ellis Irving
Original assignee: EI Du Pont de Nemours and Co
Current assignee: EIDP Inc
Priority date: 1956-11-13
Filing date: 1956-11-13
Publication date: 1960-08-23
Anticipated expiration: 1977-08-23

Description

nited States Patent Chine 2,950,237 Patented Aug. 23, 1960 IIVIPREGNATION PROCESS Filed Nov. 13, 1956, Ser. No. 621,536

Claims. or. 117-144 No Drawing.

This invention relates to a process for treating regenerated cellulose pellicular articles. More particularly, it relates to a process for decreasing the ink-transfer and pigment-diffusing properties of regenerated cellulose articles by controlled immersion in a bath containing a quaternary ammonium compound.

Regenerated cellulose articles in the form of bands, i.e., short lengths of tubing, are well known to be useful as secondary closures for jars and bottles. The bands usually are suitably decorated by pigmentation and/or printing. After manufacture, the bands are usually packed in liquid-tight containers together with a suitable liquid to maintain the regenerated cellulose in the gel state, for storage and/ or shipment to users. This liquid is typically a solution containing suitable preservatives, e.g., fungicidal and bacteriostatic compounds, rust-inhibiting agents, softeners, etc.

Among the known preservatives useful in such storage and shipping liquids are quaternary ammonium compounds, e.g., quaternary ammonium halides. However, it has been a disadvantage of such use of such compounds that, when present in the shipping liquids in suflicient amount to provide satisfactory preservative effect, e.g., mold-resistance, undesirable printing ink-transfer and bleeding or diffusion of pigments occurs. The transfer and bleeding occurs primarily from the regenerated cellulose bands into the shipping liquid, from where it readily stains other portions of the bands, but also tends to spread somewhat laterally within the bands, resulting in a hazy and less sharp printing pattern or pigmented image.

It is therefore an object of this invention to provide a process for reducing the printing ink-transfer and pigment-diffusing tendencies of regenerated cellulose pellicular articles in the gel state. Another object is to provide such a process which permits the use of quaternary ammonium compounds as a preservative in a shipping solution without resultant undesirable ink transfer or pigment bleeding into the shipping solution. A further object is to provide such a process which permits the use of quaternary ammonium compounds as a preservative in the shipping solution in smaller amounts than heretofore possible without destroying its eifectiveness as a preservative. A still further object is to provide such a process which is simple, economical, easily reproducible and capable of adaption to a continuous process. Still other objects will be apparent from the following description of the invention.

The invention in its broadest aspects comprises the process of treating a regenerated cellulose pellicular article in the gel state With a bath containing from 0.2 to 0.5% of a quaternary ammonium preservative compound for a time sufiicient to impregnate said article with at least 0.2% of said ammonium compound while maintaining the pH of said bath between 7 and 8. The stated percentages are by weight based on the dry weight of the regenerated cellulose article.

In one important aspect, the process of this invention comprises immersing a regenerated cellulose pellicular article in the gel state in an aqueous bath containing from 0.2 to 0.5% of a quaternary ammonium halide for a time sufficient to impregnate said article with at least 0.2% of said ammonium halide while maintaining the pH of said bath between 7 and 8 and the temperature of said bath between and C.

In a preferred embodiment, the invention comprises the continuous process of dipping regenerated cellulose tubing in the gel state in an aqueous solution of 0.2 to 0.5 diisobutyl phenoxy ethoxy ethyl dimethyl benzyl ammonium chloride for a time suflicient to impregnate said tubing with at least 0.2% of said ammonium chloride While maintaining the pH of said solution between 7 and 8 and the temperature of said solution between 75 and 80 C. This particular ammonium compound is preferred because of its outstanding regenerated cellulose preservative characteristics.

The treatment time required, i. e., the time sufiicient to impregnate the regenerated cellulose article with at least 0.2% of the quaternary ammonium compound, will depend on such variables as the amount and type of ink and/or pigments in the regenerated cellulose article, the thickness of the article, the temperature of the treating bath, the presence of other additives in the treating bath, etc., and to a small degree the concentration of the ammonium compound in the treating bath. Generally, the rate of impregnation will be faster in cases where there are less filters in the regenerated cellulose article, where the article is thinner, where the temperature of the bath is higher and where there are no additives in the bath. Practical treatment times for the preferred embodiment of this invention have been found to be within the range of 20 to seconds but it is to be understood that the process of this invention is not limited to this range. Suitable treatment times will be readily determinable by persons in the art in accordance with the teachings set forth herein.

The impregnation treatment may occur in a single immersion or in more than one dip in the impregnation bath. It has been found advantageous to treat a regenerated cellulose article of a tubular structure in a continuous manner by passing the flattened tubing around a series of guide rollers, some of which are beneath the surface of a bath of the treating solution. The tubing thus travels into and out of the bath in a series of successive dips or immersions, for a sufiicient treatment time, after which the tubing may be cut into bands and packaged by procedures well known in the art.

The treating bath must contain at least 0.2% of the quaternary ammonium preservative compound, based on the dry weight of the regenerated cellulose article, in order to impregnate the article with at least 0.2% of the compound. This minimum impregnation is necessary to provide a satisfactory amount of preservative in the article. It has been found, surprisingly, that the treating bath must not contain more than about 0.5% of the quaternary ammonium compound, or printing inktransfer and bleeding of pigments, which this invention avoids, will subsequently occur.

It is an essential part of the process of this invention that the treating bath be maintained at a pH between about 7 and 8. When the pH is below about 7, the quaternary ammonium preservative compound tends to lose its high bacteriostatic potency. When the pH is above about 8, subsequent ink-transfer and bleeding increases to an unacceptable amount. Control of the pH within this range may be accomplished by well known methods, such as the addition of suitable acidic or basic compounds.

The impregnating bath temperature is not particular- EXAMPLE I Regenerated cellulose tubing having the gold pigmentation and coloring ingredients described in Example 3 of OConnell U.S. Patent No; 2,716,614 was overprinted while in the gel state as followsz Solution A g a Parts Naphthol ASG (diaceto-acetyl-o-toluidide) 12.9 Naphthol AS (anilide of beta-hydroxynaphthoic acid) 38.4 Monopole oil 15.0

Sodium hydroxide (20% aqueous solution) 146.0 Distilled water 181.5

The naphthol AS-G, naphthol AS and monopole oil with a little of the water were rubbed together to form a paste. The remainder of the. water and the sodium hydroxide were added to the paste and the mixture was boiled for 15 minutes.

Distilled water- 17.5

The ingredients of solution B were mixed by thorough stirring.

Solution A was applied to one surface'of the regenerated cellulose tubing by means of a roll. Solution B was applied to the printing dies on a press roll, which was then rolled on the tubing. As the naphtholated surface 'ofthe tubing passed under the inked dies, chemical coupling action occurred and the design penetrated into the tubing in black. The printed tubing was then passed through wash Water to effect purification. Excess wash water was scraped from the surface of the tubing. J

Control samples of the tubing printed as just described were cut into bands and packaged in a shipping solution which contained 1.2% diisobutyl phenoxy ethoxy ethyl dimethyl benzyl ammonium chloride by weight based on the dry weight of the bands, which is the amount required in the shipping solution by prior art methods to obtain the desired 0.2% preservative in the bands.

Other test samples of the tubing were impregnated with 0. preservative by immersion for 90 seconds in an aqueous bath containing 0.3% diisobutyl phenoxy ethoxy ethyl dimethyl benzyl ammonium chloride by Weight based on the dry weight of the tubing. The bath temperature was held in the range of about 78 to 82 C. The tubing was then cut into bands and packaged in a shipping solution containing 42% glycerine, 0.6% sodium nitrite and only 0.06% diisobutyl phenoxy ethoxy ethyl dimethyl benzyl ammonium chloride (to preserve the shipping solution).

. Both the control samples and the test samples were subsequently examined. Both showed no wet band mold after storage in the shipping package for 200 days. The shipping solutions also showed no deterioration. The bands were then dried and both were examined after 1416 hours in the dry state and showed no mold. However, control samples which were examined after only 2 daysin the shipping package showed a severe amount of printingink transfer and bleeding of pigments and were unacceptable, while test samples which were examined after 200 days in the shipping package showed no trace of ink transfer or pigment bleeding.

EXAMPLE II Example I was repeated except that red printing ink was applied using the following printing solutions:

The results were the sameas in Example I.

EXAMPLE III Example II was repeated except that the regenerated cellulose tubing had the White opaque pigmentation and coloring ingredients described in Example II of Evans U.S. Patent No. 2,141,744. Both the control samples and the test samples showed no wet band mold after storage in the shipping package for days. The shipping solutions also showed no deterioration. The bands in the dry state for 1128 hours also showed no mold. However, control samples which were examined after only 2 days in the shipping package showed a very severe amount of printing ink transfer and bleeding of pigments and were unacceptable, while test samples which were examined after 195 days in the shipping package showed no trace of ink transfer or pigment bleeding.

EXAMPLE IV Example I .was repeated except that the regenerated cellulose tubing contained as pigmentation and buff coloring 14% titanium dioxide, 0.225% Hausa Yellow G and 0.21% Sulfanthrene Pink FF. The Hansa Yellow G and the Sulfanthrene Pink FF are described, respectively, at pages 634 and 638 of The Chemistry of Synthetic Dyes and Pigments, edited by H. A. Lubs. and published by the Reinhold Publishing Corporation, New York, New York, '1955.

Both the control samples and the test samples showed no wet band mold after storage in the shipping package for 119 days. The shipping solutions also showed no deterioration. The bands in the dry state for 1440 hours also showed no mold. However, control samples which were examined after only 1 day in the shipping package showed a very severe amount of printing ink transfer and bleeding of pigments and were unacceptable, while test samples which were examined after 119 days in the shipping package showed no trace of ink transfer or pigment bleeding. EXAMPLE V Example IV was repeated except that the red printing ink of Example II was used. The results were the same as in Example IV.

EXAMPLE VI atives. While the preferred compounds are halides, other compounds which are useful include sulfates, nitrates, benzoates, hydroxides, etc. Suitable quaternary ammonium compounds are disclosed in United States Patents Nos. 2,087,113, 2,087,132, 2,108,765, 2,152,047 and 2,295,504. The specific preferred compounds are allyl dimethyl benzyl ammonium chloride, cetyl trimethyl ammonium chloride, cetyl dimethyl ethyl ammonium chloride, lauryl pyridium chloride, myristamido propyl dimethyl benzyl ammonium chloride, octadecyl dimethyl benzyl ammonium bromide and particularly diisobutyl phenoxy ethoxy ethyl dimethyl benzyl ammonium chloride.

The invention in its preferred form applies to the treatment of regenerated cellulose pellicular articles obtained from viscose, but it may also be applied to regenerated cellulose pellicular articles obtained from cuprammonium cellulose solution, or to the treatment of cellulose esters such as cellulose acetate, or to cellulose ethers such as ethyl cellulose or glycol cellulose which have been cast in water solution, or to pellicles of gelatin, casein and related substances. By pellicular articles are meant articles formed of a pellicule, such as bands, caps, tubes, sheets, films, ribbons, etc.

In the foregoing, the invention is described in connection with the treatment of regenerated cellulose articles in the gel state. By the term gel is meant the state in which the regenerated cellulose articles are obtained before any drying action has taken place.

Suitable pigments and related materials which are typically mixed in the regenerated cellulose include titanium oxide, titanium dioxide, barium sulphate, metal flake, talc, mica, small particles of silk fibers, dyes, and other opaqueing, coloring or decorative substances. Other additives, e.g., softeners, rust inhibitors, etc., may be included in the impregnation bath, provided of course that the pH of the bath is maintained between 7 and 8 as described above, and provided the shipping solution is also neutral and in equilibrium with the regenerated cellulose gel.

The impregnation of the regenerated cellulose article according to this invention may take place at the same time in a continuous process as the usual purification step or it may take place in a separate step after the purification step. Moreover, regenerated cellulose articles whichhave been pigmented only, or which have been printed only, may advantageously be impregnated as herein described.

An advantage of the invention is that it provides a new and simple process for reducing the printing ink-transfer and pigment difiusing tendencies of regenerated cellulose pellicular articles in the gel state. Another advantage is that it provides a preservative impregnated regenerated cellulose article which can be stored or shipped in the gel state while requiring a smaller amount of preservative in the shipping solution. A further advantage is that it provides a simple process which can be used in a continuous manner to treat a moving continuous article, e.g., a continuous tube or film, with preservative, thus enabling reuse of the treating solution, a feature not possible when the preservative was only added to the shipping solution. Still other advantages will be apparent from the above.

The invention claimed is:

1. A process for storing a pigmented regenerated cellulose pellicular article in the gel state which comprises first treating said article with a solution containing from 0.2% to 0.5% of a quaternary ammonium halide at a pH between 7 and 8 for a time SllffiCiGIlt to impregnate said article with at least 0.2%, based on the dry weight of the article, of said quaternary ammonium halide; and, thereafter, maintaining said article in contact with a quaternary ammonium halide for an extended period of time.

2. A process as in claim 1 wherein said solution during the first treating step is maintained at a temperature be tween C. and C.

3. A process as in claim 1 wherein said quaternary ammonium halide used in the first treating step is a quaternary ammonium chloride.

4. A process as in claim 1 wherein said quaternary ammonium halide used in the first treating step is diisobutyl phenoxy ethoxy ethyl dimethyl benzyl ammonium chloride.

5. A process as in claim 1 wherein said solution used in the first treating step is an aqueous solution of the quaternary ammonium halide.

References Cited in the file of this patent UNITED STATES PATENTS 2,004,476 Barz et a1. June 11, 1935 2,040,061 Munz May 5, 1936 2,123,154 Schirm July 5, 1938 2,432,085 Bley Dec. 9, 1947 2,680,057 Janes June 1, 1954 2,741,534 Pedersen Apr. 10, 1956 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,950 2l7 August 23 1960 Ellis Irving Lichtblau It is hereby certified that error appears in the-printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, line 30, for "filters" read fillers column 5, line 5, for "2,08%113" read 2,087,131

Signed and sealed this 4th day of April 1961 (SEAL) Attest: ERNEST W. SWIDER XXXXXXX ARTHUR W. CROCKER Attesting ()fiicer Acting Commissioner of Patents

Claims

1. A PROCESS FOR STORING A PIGMENT REGENERATED CELLULOSE PELLICULAR ARTICLE IN THE GEL STATE WHICH COMPRISES FIRST TREATING SAID ARTICLE WITH A SOLUTION CONTAINING FROM 0.2% TO 0.5% OF A QUATERNARY AMMONIUM HALIDE AT A PH BETWEEN 7 AND 8 FOR A TIME SUFFICENT TO IMPREGNATE SAID ARTICLE WITH AT LEAST 0.2% BASED ON THE DRY WEIGHT OF THE ARTICLE, OF SAID QUATERNARY AMMONIUM HALIED, AND, THEREAFTER, MAINTAINING SAID ARTICLE IN CONTACT WITH A QUATERNARY AMMONIUM HALIDE FOR AN EXTENDED PERIOD OF TIME.