Manufactoring process of a ferromagnetic paste of impression.

The present invention relates to a method for the manufacture of a printing paste ferromagnetic particularly suited for applying markings ferromagnetic on tracks or strips of fibrous materials such as tertiles or papers, and the invention also relates to the printing paste thus obtained.

When printing such paths in different colors, the inks are applied in several individual operations, these operations that may be performed in one pass on a machine or distributed across multiple machines. For SSO operations, the track must be held in a position such that patterns in the different colors can be arranged tightly bound. The adjustment of the correct position of the track for printing multiple colors can be accomplished more easily by providing the path, for these operations, markings landmark for the successive processing steps. These markings must not allow physical setting accurate positional pathways or tapes and must also have a composition, in particular with regard pathways or textile strips, that they cannot be attacked by mechanical and chemical processing during manufacture. It is submitted that there is as much as possible without influencing the touch and appearance of the equipment, particularly when it is a track or textile web.

A ferromagnetic mark is particularly appropriate for the adjustment of the correct position of the track or band.

Ferromagnetic products such as ferromagnetic inks are known, and are used among other things in 1' lithographic industry for the manufacture of reproductions * although SSO products would be suitable for the ferromagnetic physical setting of the position of the tracks or bands, they are only not less unusable in the present purpose, because it is necessary to perform a number of additional conditions that render spéoialeaent difficult a paste composition of this type. For so far as is known, there is not dono ferromagnetic pastes that can be used in order to present.

The following conditions may be ieçosées paste of this type:

1, The ferromagnetic material in the dough, in general and mainly iron powder, should not e&Limenter during use;

2, Printing paste should have viscosity characteristics such as with LAS-oriented position of the applicator member distributes the print paste, said paste printing cannot under the influence of the force of gravity to flow out of said member, and a small amount of ferromagnetic material can, without die threads, be metered in each time through a small opening in proportions exactly reproducible and under an overpressure j is minimal

3 Paste should be retained by the track fibrous in-most ' brief delay as possible, preferably in a fraction of a second; "

4 · after application on the track and the drying, the fix, especially in terms of textile conoerne pathways, it should withstand without need for additional, both at room temperature by that at higher temperatures, treatments with acid or alkaline aqueous solutions, solutions of saponification, organic solvents and the like. The registration points must also be able to resist to a combination of these agents, and mechanical operations and cleaning;

5, The dough needs to have a very high iron content, so that with a relatively small point to provide a large magnetic sensitivity;

6, - The fix must not exert a detrimental influence

. the appearance and feel of the article. This point must therefore be very small, preferably less than 1 mm.

With the present invention, a method for manufacturing is performed PTFE printing meeting these criteria, and particularly suitable for adjusting the position of channels or fibrous webs to be printed, said method being characterized by the fact that two mixing with at minimal a proportion, calculated on the total amount of solid material, of 85 lo by weight of ferromagnetic material, a cellulose ester as a binder, and a sufficient amount of solvent with boiling point higher than 130 °c, so as to obtain a viscosity such that undesirable clumping is avoided. The cellulose ester binder, even very small concentration relative to the solvent, gives a viscous liquid for minimizing sedimentation of the iron powder. This condition (see also the point 1 above) is met as the viscosity reaches a value of about 50, and more<300 cp, the upper limit are obviously determined by the condition indicated at point 2 above.

The binder, solvent evaporation or absorption thereof through the fibrous, is also resistant to aqueous media and organic solvents as such RO RO heretofore have been described, and possesses the property, concentration relatively small with respect to the relatively large amount of iron powder, maintain this iron powder attached to the fibrous track, when - " I is exposed to the intervention of the foregoing.

As binder, preferably used nitrocellulose, and the used herein by a nitrocellulose cellulose treated in known manner with a mixture of nitric acid and d * sulfuric acid which may contain one to three groups nitrate by the glucose unit.

The choice of the solvent is determined by virtue of the condition that the cellulose ester, preferably nitrocellulose, capable of dissolving, should not evaporate too quickly then, and, should not instead have a boiling point too low, since otherwise the flow opening of the applicator member would dry and would block. It is submitted that the solvent is capable of imparting to the paste viscosity values indicated. Suitable solvents satisfy these conditions are amyl acetate, toluol, diacetone alcohol, diethylenic glycol monomethyl ether and mixtures of these products. A mixture particularly suitable is oelui of amyl acetate and ether monomethylic diethylenic glycol, found commercially under the designation "Methyldioxitol"•

The nitrocellulose is preferably used in condition stabilized, e.g. in the form of a product * 35 to 65 $stabilized with 1° ethanol.

The relative proportions of binder, solvent and iron powder are selected such that the conditions stated above are fulfilled.

By starting from a mixture containing 1000 g of iron powder, requires that are present year least 50 grams of nitrocellulose (which may be stabilized), with varying amounts of solvent, e.g. 400 - 800 cm3.

An appropriate composition comprises about 5 - 10 $nitrocellulose by weight, calculated on the total amount of solid material. The manufacture of the mixture may be carried out by dissolving nitrocellulose in the solvent and addition of iron powder. As ferromagnetic material, preferably employed is a super fine glass powder with a grain size that is preferably between 0, 2 x 1the U and 0.8 9.ï 10' millimeters. These indications are also valid for cellulose esters other than nitrocellulose.

Such as I

CTO a printing paste prepared by dissolving 100 g of nitrocellulose are stabilized in 200 cm3 of amyl acetate and 240 cm3 of Methyldioxitol, then stirring and adding 1000 g of iron powder with a grain size of 0, 5 x 10 *" ^ mm in average. The printing paste obtained, which had a viscosity of 50,000 cp (20 °c), was utilized as a filler. to fill a number of organs of applications detached which were subsequently mounted peripherally of a roller réyolutif. The application members were in communication with duct openings for feeding the printing paste in the application amounts of provided.

The printing paste was kept under slight overpressure, to provide control of the output of the pulp with the duct opening, it has been found that what library an overpressure of 0.2 kg, proceeds a very small flow which was sufficient accurately point the desired size (for O, 06 mm3 per dot). The roller rotational included three application members and had a rotational speed of 120 t/m, so that this regard than half a second for the output of the printing paste out of the applicator member, and that a fraction of a half-second for applying the paste onto the tissue to be treated. The point obtained was resistant treatments fabricfinishing customary. When the application members are not used directly after filling, and remain stored for one day, in the case of rotational movement year idling, it has been found that it is not occurring sedimentation of the iron powder, and that the applicator member filled is always immediately usable.

Such as II

Table A indicates a number of pastes according to the present invention, these pastes containing components in varying proportions.

A nitrocellulose/i5e the HP grams

GBP with 35 with fo ethanol)

* D-amyl acetate per ml

Toluene ml.

Alcohol diacetene ml.

Ifethyldioxit LO ml.

Ρ℮ (θ, 2 - 0.8 Nieron) grams

% fe relative to the

amount of total material

solid