CS235144B1 - Hot melt powder for finishing of printed matter - Google Patents

Abstract

The invention relates to a fusible powder intended for the production of plastic printing, or for obtaining a glossy coating on products of the printing or paper industry. The fusible powder based on a mixed resin consists of an esterified epoxy resin based on diane with a molecular weight of 1500 to 3000 and higher acids with a hydrocarbon skeleton of C 12 to C 20, or their hydroxy derivatives or halogen derivatives, together with rosin or adducts of rosin and alkyl resole with a molecular weight of 400 to 650

Description

The invention relates to a fusible powder for plastic printing, i.e. for refining printed matter, in particular in the manufacture of mercantile printed matter, for use in the printing and paper industry.

In the production of some mercantile prints, such as letter papers, envelopes, business cards, various occasional announcements, invitations, leaflets, diplomas, etc., printing is usually done by letterpress or offset printing. The resulting product is further refined by dusting with a meltable powder of suitable grain and melting point, and then removing the powder from impermeable sites by cellaring or suction. In printed areas the powder adheres to a color that has not yet dried up. After the printed matter has been heated to the melting point of the powder, for example by passing through a heated tunnel, the powder is set up and forms a glossy relief layer.

This highlights the printed text or image, so-called plastic print.

The basic requirements for these fusible powders are health safety, appropriate granulation, adequate softening point, good color wetting, high flowability and usually transparent film formation. The health of the powder must not be manifested even during its melting, ie at temperatures of 100 to 180 degrees Celsius, no toxic decomposition products must be produced. The softening point should not be lower than 50 ° C to avoid sticking to the prints when heated accidentally. On the other hand, it must not be too high so that the sintering of the powder does not require a high temperature which would adversely affect the paper. The usual grain size of the powder is 8 to 200 µm. The choice of powder granulation depends on the size of the printed font or the fineness of the drawing. An example of a fusible powder of suitable properties is a powder whose preparation, properties and uses are described in DOS 2 215 080, the object of which is based on a mixture of polymers containing hydro groups and adducts of ε-caprolactam, diisocyanates and polyalcohols. The production of such a fusible powder is complicated, requiring well-dried raw materials and preventing the entry of air humidity.

These drawbacks are overcome by the mixed resin melt powder of the present invention, which is based on esterified epoxy resins based on diane with a mole. weight of 1500 to 3000 and higher acids with C 12 to C 20 hydrocarbon skeleton, respectively. their hydroxy or halogen derivatives and the rosin or adducts of rosin with alkyl resols of mol. The weight ratio of the esterified epoxy resin and rosin resp. its alkyl resoles adducts are 1: 0.05-0.3.

Fatty acids of linseed oil or hydroxystearic acid may be advantageously used to esterify the epian resins based on diane. The esterified epoxy resin should have an acid number of less than 5 mg KOH / g. Preferably, p-tert-butylresol can be used to prepare rosin adducts. The weight ratio of the esterified rosin is governed by the melting point softening point requirement. The softening point can range from 60 to 90 degrees Celsius.

The melt powder is obtained by grinding the mixed resin to the desired grain size and screening for the grain size on the sieves. It is designed for making plastic print, event. obtaining a glossy coating on products of the printing or paper industry.

The hot-melt powder according to the invention is distinguished by its health safety and simplified production technology.

The following examples illustrate the invention and its application.

Example 1

1. Preparation of esterified epoxy resin

The reactor was charged with 2000 g of dian based epoxy resin of mol. weight 2000 and softening point 94 ° C. The batch is heated to 150 DEG C. and 560 g of flaxseed fatty acids are added in one portion. It is left for 30 minutes at 150 ° C and gradually heated to 200 ° C. If the acid number drops below 5 mg KOH / g, the mixture is omitted.

2. Preparation of rosin adducts

700 g of rosin having an acid number of 162 mg KOH / g and 400 g of p-tert-butylresol with a softening point of 80 to 90 ° C are introduced successively. The shaft is heated gradually up to 230 ° C. From 130 ° C, 40 g of condensate containing 3-5% of terpene hydrocarbons are gradually distilled off from the reaction mixture. The reaction was stopped at an acid number of 115-125 mg KOH / g and a softening point of 147-160 ° C.

3. Preparation of mixed resin

The rosin adducts are mixed at a temperature of 150 to 200 ° C in a weight ratio of 5 to 30 why. % with an esterified epoxy resin. The molten mixture is drained, allowed to cool and then crushed in a ball mill with the addition of water and a wetting agent. After crushing and decanting the water, the resin is dried at a temperature of max. 40 ° C and further screened. The screened powder is used for dusting the printed matter when making a plastic print.

Example 2

The process for the preparation of the mixed resin is the same as in Example 1, but 580 g of hydroxystearic acid is used in the esterification of the epoxy resin.

Claims (1)

OBJECT OF INVENTION A fusible powder for the refinement of mixed resin prints, characterized in that it consists of a esterified epian resin based on diane with a mol. weight of 1500 to 3000 and higher acids with C 12 to C 20 hydrocarbon skeleton, or their hydroxy or halogen derivatives, together with rosin or with adducts of rosin and alkylresol of mol. weight of 400 to 650, wherein the weight ratio of esterified epoxy resin to rosin or adducts of rosin with alkyl resols is 1: 0.05-0.3.