IL24467A - Fabric for the production of stencils for screen and serigraphic printing and process for producing same - Google Patents

Description

P.A.24467 File 13716 2.11.69 PRODUCTION FABRIC FOR THE Β¾ΒϋΤίθΝ OF STENCILS FOR SCREEN AND PROCESS SERIGRAPHIC PRINTING- AND ΜΕΤΗθΒ FOR PRODUCING SAME -|T7nm τωατ nun nnujir? WE, L»UNION GAZES A BLUTER, a French Societe Anonyme, of 2, rue de la Republique, Lyon, Rhone, France.

P.A.24467 Pile 13716 2.11,69 This invention relates to improvements in the fabrics used for making stencils for screen and serigraphic printing'. The improvements consist in the application of a coating having as a basis at least one polymerized vinyl compound on a fabric intended for making such stencils.

Said application of a vinyl solution followed by a polymerization of the vinyl compound leads to a perfect adherence between the solution and the single and&ulti-filaments forming the threads of the fabric. The solution applied is generally of a dull white colour, but it can be colored blue, if required, in order to allow a checking of the homogeneous distribution of the solution throughout the fabric and of its stability in the event of a subsequent washing.

This application of a solution of a vinyl product and the subsequent polymerization of the vinyl compound on the fabric results in the following advantages in the making of the stencils. - the vinyl solution applied to the fabric prepares it for a better adherence of the sensitive layer which may be applied without any preliminary scouring; furthermore i the hand finishing usually required is generally not necessary anymore* This results in a saving of time and also to an improved technique; - the application of the solution to the fabric im roves its resistance to heat and moisture Ρ.Δ.2 67 File 13716 .2.11.69 -! in the case of a fabric constituted by multi^ strand threads, the vinyl solution applied to the fabric acts as a protective coating fo the threads and prevents the penetration of dyestuffs and printing inks between the strands forming each individual thread } as a result, the screens are easier to clean and consequently a further saving of time is obtained. - the photosensitive layer applied subsequently to the thus coated fabric adheres better to same by reason of the preliminary application and polymerization of the vinyl compound; and as a result the sharpness and clearness of the pattern are more wear-resistant; - the application of the vinyl solution to the fabric gives the latter some stiffness and facilitates its correct mounting in a frame; the meshes of the fabric are locked against relative shifting and it is easier to get a screen with straight threads.

The following is an example of an application of the invention to the making of fabrics for the preparation of stencils for use in textile-flat printing.

The fabrics may be manufactured, starting from monofilament polyamide 6, or from multifilament polyester fibers. The fabrics must be in accordance with..French standard norm MFG 37.001. In the said norm the fabrics comprise ordinarily weft and woof threads in the range of 33.5 to 80 threads per centimeter in the case of multifilament polyester Ρ.Δ.24467 File 13716 2.11,69 The numeric arrangement of the threads is generally in accordance with the progression of ordinary numbers of. the R20 series.

The coating of such a fabric is effected by using an aqueous vinylic solution diluted in convenient proportions according to the mass of threads to be coated, the fluidity of the solution being in proportion to the density of the fabric mesh per centimeter. The vinyl additive is coloured a light blue, in order - on the one hand - to distinguish the product according to the invention from known ones, on the other hand to have a means of checking the homogeneity of the application of the coating on the fabric.

In fact, in its natural state the vinyl coating is absolutely colourless, but without adding a colouring agent its dispersion cannot be effectively checked. Thus it might happen that the irradiation with sunlight may result in under-exposed and overexposed spots.

Finally, the vinyl coating is polymerized at a convenient temperature which - at the same time - ensures the stabilization of the polyamide or polyester threads.

Amongst compounds suitable for the application of a coating according to the present invention there may be mentioned vinyl chloride, vinyl acetate* polyvinyl acetate, polyvinyl alcohol and fluorinated polyvinyl compounds.

EXAMPLEt The tlftsue is inserted into a solution containing 30 to 100 g of the vinylic compound per liter of aqueous or alcoholic solution. The concentration is adjusted to the tissue used.

The coating of the threads is effected instantaneously by this dipping into the solution and this solution penetrates into the threads of the fabric. The penetration is further enhance c/ if it is effected at a slightly elevated temperature* such as in the range of 30 to 35°C. The tissue is maintained in the solution for about 1 minute and is taken out. After this it is passed through a device adapted to scrape off superfluous coating material* which at the same time also ensures the uniformity of the coating. This is easily controlled if a small quantity of blue coloring material is added to the solution, and thus the uniformity of the coloring of the tissue indicates the degree of uniformity of the coating.

At this stage the openings in the tissue are completely blocked and it is necessary to open these up. This is effected by the application of suction which breaks up the coating and opens up the openings in the mesh. The coating material retracts from the openings and thus the coating of the fibres Is further enhanced. After this the tissue is subjected to a polymerization process at azi elevated temperature o ■ \ of about 200 C. This permanently affixes the vinylic compound to the tissue and imparts to the stencil the advantageous properties set out above.

Claims (2)

P.A. No. 2kk67 File 13716 Date 13.x.6 WHAT IS CLAIMED IS , .

1. · As a novel article of industry* a fabric for the executio of screen and serigraphic printing stencils impregnated with and comprising a coating having as a base at least one polymeric v¾nyl compound,

2. A process for producing a fabric for the execution of screen and serigraphic printing as claimed in Claim 1 which comprises impregnating said stencil-forming fabric with a composition having as base at least one vinyl compound and polymerizing this composition* \ 3· A method for treating fabrics fo printin stencils and fabrics and stencils obtained thereby, substantially as described. h. Stencils for screen and serigraphic printing, whenever obtained by a process as claimed in Claim 2 or Attorneys for Applicants.