DE2519136A1 - METHOD OF COLOR PRINTING A DOCUMENT - Google Patents

Description

MÜLLER-BORG ■ GROEMING · DcUFEL - SCHÖN ■ HERTEL

PAITNTAiSiWA ₁ -TE
BRAUNSCHWEIG · MUNICH ■ COLOGNE

Dr. W. Müller-Bore ■ Braunschweig H. Groaning. Dipl.-Ing. ■ Munich Dr. P. Deufel, Dipl.-Chem. Munich Dr. A. Schön, Dipl.-Chem. · Munich Werner Hertel, Dipl.-Phys. · Cologne

Munich

2 9. A?> F ff

D / S / Gl - B 1209

BRITISH INDUSTRIAL PLASTICS LIMITED, Manchester, England

Process for color printing a document

The invention relates to color printing of documents, for example Textiles.

One of the methods used for color printing of textile materials is the vapor phase transfer method, when carried out, on a fabric by contacting a pattern printed on a textile, paper or other medium and usually consisting of one or more volatile disperse dyes the printing with the fabric is transferred under controlled conditions with regard to time, pressure and temperature. Disperse, which sublimate in the region of 180 ⁰ C are commonly used. However, this method cannot be applied to fabrics made from natural fibers with acceptable results. It is most frequently used for color printing of polyester fabrics, polyamide fabrics (although the color fastness can be extremely poor) and certain acrylic

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Office Munich: 8München86 - Siebertstr. 4 P.O. Box 860720 Cable: Muebopat Munich Telex 5-22050, 5-22659 Telephone (089) 471079

weave. In the case of a mixed polyester / cotton fabric the pattern tends to take on a marbled or "choppy" appearance because of the dyes versus the cellulosic fibers are not noun. Other substrates show the same or more serious disadvantages.

The invention relates to a method for color printing of substrates, in carrying it out a substrate coated with an alkylated melamine / formaldehyde resin, as further defined below is, has been treated, is subjected to a transfer printing.

According to another embodiment, the invention relates to a Color printing process in which, when carried out, a substrate or an underlay is subjected to a transfer printing, the printed one Substrate is treated with an alkylated melamine / formaldehyde resin, as it is defined in more detail below.

The alkylated melamine / formaldehyde resin is a resin that has units the general formula:

wherein R .., R ₂ , R ₃ , R ₄ , R ₅ and R _{g are} each selected from hydrogen atoms and -CH ₂ OR groups, wherein R is also a

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_ J mm

Represents hydrogen atom or a methyl, ethyl or propyl group, and wherein 0 to 2 moles of hydrogen atoms and 4 to 6 moles of -CH ₂ OR groups are present per mole of the melamine nucleus and at least 1.5 moles of the R groups are not hydrogen atoms. The units of the general formula I which form the resin can be present as monomers or as oligomers thereof or as a mixture thereof, where preferably 4 to 6 mol of the groups R are not hydrogen atoms, specifically per mol of the melamine nucleus.

The alkylated melamine / formaldehyde resin is preferably in melamine resin, nominally a hexamethylolated resin, meaning that the average number of methylol groups per melamine core approaches 6, this resin having a relatively high solids content possesses, for example in the order of 90% by weight of the reactive solids content.

The amount of alkylated malemine / formaldehyde resin solids that present as a coating on a substrate or represent an impregnation in the substrate, is preferably between 0.5 and 10% by weight of the substrate, depending on the material of the substrate and the desired properties of the product. That The substrate is preferably a textile material, in particular a material made of natural fibers or a mixture of these Fibers composed of synthetic fibers, but it can optionally consist of another material, for example made of wood or a composite material, for example a resinated felt.

The use of an alkylated melamine / formaldehyde resin as defined above does not preclude further treatment of the substrate with one or more other finishing agents, such as other resins, waterproofing agents or the like, provided that such other finishing agents

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a) are compatible with the alkylated melamine / formaldehyde resin and b) for a use to carry out a transfer printing process or on the product obtained thereby.

The alkylated melamine / formaldehyde resin can be used in an aqueous or in an organic solvent system and normally requires catalysis by the addition of a catalyst. Suitable catalysts are magnesium chloride, (NH ₄ ) ^ HPO ₄ , (NH ₄ ) H ₂ PO ₄ , zinc nitrate, ammonium sulfate, nitrate, chloride or thiocyanate, phosphoric acid, hydrochloric acid or nitric acid or organic salts. Metallic iron catalysts can produce undesirable color changes in the case of some dyes. Their effectiveness should be tested before printing is started.

The process of treating the substrate as well as the transfer printing can be carried out by one of several methods, for example by one of the following methods:

a) The substrate is treated with the resin, followed by the treated Substrate is dried and heat treated. Then the heat treated substrate is printed.

b) The substrate is treated with the resin, then the treated is Substrate dried. The dried substrate is then printed, the resin cured and the print at the same time is fixed.

c) The substrate is printed, whereupon the resin to fix the Printing is treated.

d) The substrate is treated with the resin, whereupon the resin is steamed or is cured wet. Then the treated substrate is washed, whereupon the washed substrate is dried and is then printed.

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The substrate can be treated with the resin using a conventional padding technique. Furthermore, the resin can be applied to the Substrate can be sprayed on or applied by means of a roller. Any other suitable method can be used.

The following examples illustrate preferred embodiments of the invention. Example 1 is a comparative example that shows a known transfer printing process and serves as a comparison.

Example 1 (comparative example)

A woven textile material consisting of 100% polyester, is subjected in the way a transfer printing that a commercially available transfer paper to the fabric at 200 is contacted to 210 ⁰ C for a period of 3 minutes to the Dispersfarbstoffmuster to the textile material to transfer on paper. The textile material which has been printed by transfer printing and which is obtained in this way shows good color depth and color fastness.

Example 2

A »A methylated melamine / formaldehyde resin, the monomers and oligomers of units of the general formula given above and an average of about 0.5 hydrogen atoms, about 0.5 -CH ^ OH groups and 5 -CH ₂ OCH - groups per Melamine core having at least 95% solids by weight formed upon curing is dissolved in water to a concentration of 80 parts by weight of the resin per 1000 parts by weight of water. In addition, 2 parts by weight of monoammonium dihydrogen phosphate per 1000 parts by weight of water are added as a resin curing catalyst. A textile material made of a 50/50 mixture of cotton and polyester is mixed with the resulting solution to a moist

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70% absorption capacity impregnated. A treated Obtained textile which, after drying, contains approximately 5% by weight of the resin solids, based on the weight of the textile.

The dried and treated textile is subjected to a transfer printing process using the same transfer paper that is used has been used to carry out Example 1, and the same transfer printing conditions are observed.

The color depth of the printed textile is slightly less than that of the product of Example 1, but good color fastness is found even after washing.

B. A textile as defined under A is printed using the same transfer paper, but without pretreatment with the resin.

The product obtained has poor depth of color and shows poor color fastness due to peeling of the dyes of the cotton component during washing. This shows the beneficial effect of the resin treatment.

Example 3

A. A 100% cotton textile is treated with a methylated melamine / formaldehyde resin and then treated printed, proceeding exactly as in Example 2. The color depth of the product is acceptable, as is the Color fastness after washing.

B. A 100% cotton fabric that does not has been treated with the methylated melamine / formaldehyde resin.

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is printed according to example 1. The product obtained has poor color depth and practically no color fastness To wash.

The depth of color and the color fastness of the textiles made of natural fibers or of textiles which contain natural fibers and according to the invention have been treated, can be due to slightly increased transfer printing times and / or temperatures compared to the transfer printing times and / or temperatures, which are maintained in the case of polyester textiles, are increased. A printing time of 3 minutes was followed to carry out the preceding examples. Sufficient hardening of the respective used is thereby achieved Resin achieved. However, this period of time may vary if necessary in the case of resins having other curing properties can be changed, for example from 30 seconds (normal printing time) to 5 minutes.

The invention is also applicable to other substrates, for example on asbestos textiles, composite materials and wood, i.e. on materials on which the previously known transfer printing methods cannot be used in a satisfactory manner.

When printing textiles, use the procedure described under b) the most preferable. There may be some color fastness and depth of color in the case of certain synthetic fibers, such as polyester fibers, are lost, but this is due to these properties on the cotton of a blended Cotton / polyester textile material more than made up for it. In in most cases a very even print is achieved.

Alkylated melamine / formaldehyde resins have been used to

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For example, to give textiles a crease resistance by applying such resins as part of an after-treatment to otherwise otherwise equipped materials were applied. The invention relies on the use of similar resins at an earlier stage in manufacture, these resins being in some way act as a fixative for transfer printing dyes.

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Claims (7)

Claims 1. A method for color printing a substrate using a transfer printing process, characterized in that the substrate is coated with an alkylated melamine / formaldehyde resin of the general formula: is treated, where R, R, R, R, R_ and R _{g are} each selected from hydrogen atoms and -CH-OR groups, where R is a hydrogen atom or a methyl group, ethyl group or propyl group and 0 to 2 mol of hydrogen atoms and 4 up to 6 moles of -CH ₂ OR groups are present per mole of the melamine nucleus and at least 1.5 moles of the R groups are not hydrogen atoms, and the treated substrate is subjected to a transfer printing process. 2. The method according to claim 1, characterized in that the substrate used is a textile material made of synthetic Fibers and natural fibers. 3. The method according to claim 1 or 2, characterized in that 609847/0802 - ro - the resin used 4 to 6 moles of R groups that do not contain hydrogen ' atoms, per mole of melamine nucleus. 4. The method according to any one of the preceding claims, characterized in that the substrate after treatment with the Resin and, after drying, is printed under such conditions that the resin is hardened and the printing is fixed at the same time. 5. The method according to any one of claims 1 to 3, characterized in, that the substrate is treated with the resin, whereupon the resin in the treated substrate with steam or moisture cured, washed and dried and then printed. 6. The method according to any one of claims 1 to 3, characterized in that that the substrate is first subjected to a transfer printing process and then treated with the resin. 7. Color-printed substrate, characterized in that it is after produced by a method according to one of the preceding claims has been. 609847/0 8 02