DE1546342A1 - Process for increasing the adhesive strength of dyes, printing inks, adhesives or the like. especially on paper - Google Patents

Description

Dr. Expl.

DEUiBSCHE WMPHOBE Society for Electronic Devices mbH, Hamburg 1, olileliaus B III,

Process for increasing the adhesive strength of dyes, printing inks, Adhesives or the like. In particular on paper

The invention relates to a method for increasing the adhesive strength ability of dyes, printing inks, adhesives or the like, in particular on paper by treating the paper in an electric field.

In order to achieve sufficient adhesive strength of printing inks, adhesives or the like. On types of paper that show a repellent effect on these substances per se, it has hitherto been necessary to develop either special inks or adhesives, each for. were useful for the particular purpose or one was forced to prepare the paper in a special expensive process in such a way that sufficient adhesion of the applications was ensured , ■

In contrast, the "invention relates to a simple method, When it is used, the surfaces of papers experience such an influence in the electric field that the surface roughness dee paper ensures perfect printing or gluing Has extent. Thus, by applying the invention, it is particular no longer necessary as before, colors with adhesion promoters and to use high quality adhesives,

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BATHROOM OFIiGlNAL

In the case of plastic films, it is already known that the adhesive strength of To improve printing inks on the film surface by guiding the film over a treatment plate or roller and doing so - is exposed to high-frequency electrical vibrations «Here is either high-voltage alternating current of low frequency of z * B «50 Hz with high power or high-voltage direct current used with superimposed high-frequency alternating voltage. In both cases it is disadvantageous that special measures are taken must be * to avoid life-threatening contact with these systems to avoid and, moreover, is used in these known methods. worked with corona discharges, where relatively large.

.Ozone quantities are formed, the undesirable corrosion phenomena can affect parts of the system »

It has therefore already been proposed, the adhesive strength of printing inks on the surface of plastic films in an electrical To increase the field by causing electrical oscillations with a frequency of 20 to 50 kHz and a voltage of such Order of magnitude to be used so that no KorenaenÜadungen occur, the voltage having such a waveform that in each Half-period a voltage peak of 50 to 100 kV occurs, the one Spark formation with limited amperage between the electrodes and the film produced · In this case, such a curve shape is preferably used of the alternating voltage that its amplitude after spark formation is reduced to about 1/4 of the peak value of the voltage peak falls off.

In-depth considerations and tests have shown that the process of the type described, after appropriate modification, also successfully used to increase the adhesive strength of printing inks and adhesives Or the like. Can be used on paper, what the known

Do not allow procedure

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This goal can be achieved in that in a method for increasing the adhesive strength of dyes, printing inks, adhesives or the like. In particular on paper surfaces according to the invention, the paper surfaces are subjected to a treatment in a high-frequency, high-tension alternating field, the Voltage greater than 50,000 volts, preferably between 400,000 and 600,000 volts and a frequency of 25 to 75 kHz or more is applied*

The improvement in adhesion presumably occurs in the process according to the invention by changing the surface of the paper - possibly with a perforation - so that the paint penetrates and dries more quickly and the adhesives held on a smooth surface after treatment adhere better to a slightly roughened surface *

For the practical application of the method according to the invention, it has proven to be expedient to bring the high-tension alternating field to act on the surface of the paper or the like via electrodes of a known embodiment. The electrodes are preferably held in place with suitable insulating materials above the paper web. Below that, the paper web is guided over a roller as the opposite pole with a large dielectric Discharge is achieved, the location of the discharge on the guide roller being continuously changed as it rotates through the paper web. This eliminates the risk of the guide roller being undesirably heated or locally overheated. It is also possible, if necessary, _{to cool the roller in a manner known per se #} for example by means of a gaseous or liquid coolant *

The distance to be maintained between the electrodes and the paper web depends less on the conductivity of the dielectric of the opposite pole,

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• ORIGINAL BATHROOM

e.g. the guide role, from the level of the applied voltage, The distance is usually between 0.5 and 3 mm.

Since the achievable with the method according to the invention effect of Depending on the type of paper treated, it may in some cases be appropriate to repeat the treatment according to the invention to undertake, e.g. in such a way that several electrodes are arranged one behind the other. In the same way, several electrodes arranged one behind the other reduce the throughput speed the paper webs to be treated are significantly increased. aside from that you can arrange the electrodes, e.g. on both sides of the paper webs, that both paper surfaces according to the invention in one pass Processes can be treated, whereby the adhesive properties are improved on both sides;

The treatment according to the invention is advantageously carried out on long paper webs that are wound up on rolls, because in this way the most continuous possible operation can be carried out »

The method according to the invention can be carried out so that the Treatment in an alternating electric field immediately before printing or before gluing. However, it is also possible to separate the action of the alternating field from further processing to be carried out and the further processing to follow at a later point in time.

Claim

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Claims (7)

Patent attorney ^ '' Dipl-ing-HeinridiScfaaefer Hamburg.Wandsbek ßr. 6: - Call 652 96 56 Patent claims: 1. Process for increasing the adhesive strength of dyes, printing inks, Adhesives or the like, in particular on paper surfaces, characterized in that that the paper surfaces are subjected to a treatment in a high-frequency, high-tension alternating field, the Voltage greater than 50,000 volts, preferably between 400,000 and 600,000 volts and a frequency of 25 to 75 kHz or more applied will. " 2. The method according to claim 1, characterized in that the electrical Alternating field via a fixed electrode with one designed as an opposite pole Guide role for the material to be treated is brought to act on or through the surface of the material. 3. Process according to claims 1 and 2, characterized in that the rotating guide roller for the material to be treated is cooled will . 4. Process according to claims 1 to 3, characterized in that I the paper surface to be treated is exposed to the action of several alternating fields provided one behind the other. 5. The method according to claims 1 to 4, characterized in that the surfaces of the paper on both sides of which are exposed to the action of one or more We ^N chself fields, 6. The method according to claims Ibis 5, characterized in that the Treatment of the surfaces of paper or the like is carried out in an alternating field immediately before further surface finishing, 0 0 9817/0617 7. Process according to claims 1 to 6, characterized in that an area of action of the alternating field which is extended in particular in one direction by using appropriately designed, for example is forced from a piece of flat metal existing electrodes. 009817/0617