DE1117609B - Prevent the tarnishing of brass and bronze printing on paper and cardboard - Google Patents

Description

The present invention relates to improvements in tarnishing bronze or brass printing on paper or cardboard, regardless of whether these materials are coated or uncoated are, for example, with bronze printing on foldable cardboard. With such prints Various bronze or gold effects achieved with metallic pigments. Printing can be done that the paper or cardboard is glued with an undercolour, varnish or other coloring agent or preprinted and the design is then dusted with a fine metallic powder that made of bronze or brass. Notwithstanding this, printing can also be done by using Printing inks are made in which the fine metallic powder is embedded directly as a pigment.

The presence of sulfur or sulfur components in the atmosphere or as components of the paper and the cardboard exerts a pronounced tarnishing effect on the bronze or brass printed material made of. However, the acidity of the paper or cardboard is even more common the cause of tarnishing, especially if the material is in stacks or after printing Bundling is stored. The tarnishing is increased when such printed material is relatively high humidity and temperature is stored, with the moisture content for this Effect is particularly significant.

Other factors are also important. B. high copper content and small particle size the tendency of bronze or brass powders to tarnish. On the other hand, influence the copper content and the particle size also the color and gloss of the print, and in practice There is often a trade-off between these two factors, albeit a great one fine powders with a high copper content should be avoided.

The invention aims to prevent or prevent the blooming of such prints, in particular where the printed material is in the form of stacked sheets, folded boxes or erected boxes, especially in atmospheres of relatively high humidity and Temperature, is stored.

Up to now, no special precautions have been taken to prevent such tarnishing, which occurs either during storage or after manufacture. Also prints that are generated by dusting, in particular by dusting brass or bronze powders in be-Preventing the tarnishing of brass
and bronze printing on paper and cardboard

Applicant:

British-American Tobacco Company,
London

Representative: Dipl.-Ing. B.Wehr, Dipl.-Ing. H. Seiler,

Berlin-Grunewald,

and Dipl.-Ing. H. Stehmann,

Nuremberg 2, Essenweinstr. 4-6, patent attorneys

Claimed priority:
Great Britain May 15, 1957

David Robert Davis and Henry Herbert Evers,

London,
have been named as inventors

As is known, tend to be in atmospheres of relatively high humidity and temperature to start up. Even in the case of prints made by means of a printing medium, for example a Resin, in which the metallic powder is embedded, will be produced under unfavorable Conditions, as they have been previously specified, a start-up takes place, even if the specified Means a certain protection against tarnishing.

The invention therefore proposes as a printing material for the production of bronze or brass prints Use paper or cardboard material containing sodium or potassium borate, especially with Meta- or pyroborate, impregnated or coated in an amount of 2 to 6% of the weight of the paper.

It is already known to impregnate paper with borax or borates for packaging silver goods. The impregnated chemicals should be mixed with the sulfur present in the air react chemically to keep the sulfur compounds away from the wrapped silverware. However the ingress of sulfur compounds in bronze and brass prints is insignificant for tarnishing. It is therefore not important whether the sulfur compounds have access to the printing material

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impede. Rather, it is important to prevent tarnishing caused by contact with acidic cardboard to prevent.

It is also known to use paper, cardboard and the like for packaging metal objects to be impregnated with salts of boric acid to prevent corrosion of the metal surface. This is to prevent corrosion, especially in ferrous metals, caused by the the atmosphere surrounding the metal, for example air, is effected. For this purpose, the metal surface should be a Atmosphere which is an effective corrosion preventive acting in the vapor phase Contains amount of a salt of a boric acid. For this purpose, the metal to be protected from corrosion must be in a closed space in which the atmosphere can be created, which an in contains a boric acid salt which acts in the vapor phase. It must therefore be the metal to be protected together with the protective substance in a closed container or in paper, which is covered with the Protective fabric is provided, be wrapped. In the known method, the vapors of the Protective substance to prevent corrosion.

In contrast, it is made possible by the present invention, both the atmospheric To prevent corrosion as well as contact corrosion. In particular, the invention is the Corrosion that could occur due to a strong acid content in the paper or cardboard, effectively switched off.

According to the present invention, the paper or cardboard material is during or after Manufactured, but before printing with boric acid or potassium, such as sodium metaborate or sodium pyroborate. Depending on the material to be treated, the borate by impregnation or deposition from a suitable solution or by coating with a Coating mass take place. In the event that the paper and cardboard materials are uncoated, can it becomes necessary to treat both sides of the material, while with paper or cardboard materials, that are deleted, a sufficient degree of protective effect can be achieved if only the uncoated side is treated. The corresponding value in units of grams per Square meters of surface area of the material for the borate to be used, expressed as a percentage on a weight basis, will depend on whether the material is to be treated on one or both sides is, and will continue to depend on the basis weight of the material.

For example, paper with a basis weight of 81.72 kg (180 lbs.) For every thousand sheets, each measuring 76.20 (30 ") X 101.6 cm (40") with a 3% anhydrite borate content are impregnated, that is 2.45 kg (5.4 lb.) of anhydritic borax per 81.72 kg of the paper mentioned. On the other hand, z. B. foldable cardboard with a basis weight of 231.54 kg (5101b.) For each a thousand sheets, each measuring 76.2 X 101.6 cm and coated on one side, by knocking down treated from a suitable solution with 2 percent by weight of the anhydrite borate, that is

ίο 4.63 kg (10.21b.) anhydrite borate for 231.54 kg of the mentioned cardboard by placing either on either side of each sheet of the thousand sheets or a precipitate is generated on the uncoated side alone or partially on the uncoated side and the rest is embedded in the coating. In the event that the paper and cardboard materials are uncoated it may be necessary to treat both sides of the material while in the case of painted Paper and paperboard materials, a sufficient degree of protection is achieved by treating the uncoated side alone. Nonetheless can also, if so desired, the coated side either by precipitation or treated by embedding the borate in the coating itself.

Borate solution can be used in many forms, for example by having the paper or the cardboard passes between sets of rubber rollers to remove the solution from a container or a Trough out by spraying the solution onto the paper or cardboard before drying or calendering to transfer, or by impregnating the paper or cardboard by first putting it through migrates a trough which contains the solution, and is then dried, or by embedding of the borate in a surface coating treatment, which the paper or cardboard material during is subject to its manufacture, for example prior to painting or surface film painting.

The printing itself can be done in any known manner, in particular one of those previously discussed Procedure.

Claims (1)

Claim: The use of paper or cardboard "-rial, that with boric acid sodium or potassium, in particular with meta- or pyroborate, in one Amount of 2 to 6% of the weight of the paper is impregnated or coated as printing material for the production of bronze or brass prints. Considered publications:
German Patent No. 849 791;
U.S. Patent Nos. 1,766,646, 2,749,210. © 109 740/113 11.61