CS259830B1 - Chemical preparation for the preservation and activation of offset printing plate surfaces and molds - Google Patents

Abstract

The essence of the chemical preparation consists of substances based on polysaccharides in a mixture with polyfunctional alcohols or polymers of polyfunctional alcohols or their mixtures (for example, 1,2,3-propanetriol or polyethylene glycol in a mixture with polysaccharides). The required elasticity and flexibility of the applied film on the offset substrate are achieved. This prevents premature deterioration of printing plates or forms.

Description

The invention relates to a chemical preparation for preserving and activating the surface of offset printing plates and forms.

Existing preparations for this purpose mostly consist of aqueous solutions of colloidal substances, for example gum arabic, dextrin or mixtures thereof. These solutions are used in printers for the preservation and activation of the surface of printing plates and forms. Applying a protective film of the colloid prevents contamination and corrosion of the offset metal plate and at the same time hydrophilizes the surface for better wetting with water during the printing process. The disadvantage of these colloidal substances, whether alone or in a mixture, is the fact that the dried protective film tends to crack or peel off during prolonged storage of the printing plates, which results in corrosion, contamination and deterioration of the offset printing form. The quality of the mentioned natural colloidal substances is also substandard and sometimes the hydrophilic properties of these substances decrease and as a result, poor activation of the surface of the printing form and difficulties in the printing process, which are manifested by smearing of the ink in the non-printing area.

The above-mentioned shortcomings are eliminated by the preparation for the preservation and activation of the surface of offset printing plates and forms according to the invention, its essence is that it consists of natural polysaccharides or their derivatives in an amount by weight of 2 to 60 parts of polyhydric alcohols from the group of 1,2,3-propanetriol, dlethylene glycol, triethylene glycol and polyethylene glycols in an amount by weight of 0.2 to 30 parts, a preservative in an amount by weight of 0.05 to 1 part, a water-soluble dye in an amount by weight of 0.001 to 1 part, phosphoric acid in an amount by weight of up to 10 parts, ethyl alcohol or isopropyl alcohol in an amount by weight of up to 5 parts and water in an amount by weight of 30 to 98 parts.

The addition of polyhydric alcohols 1,2,3-propanetriol or diethylene glycol, triethylene glycol, polyethylene glycols in a mixture with polysaccharides achieves the required elasticity and flexibility of the applied film of the preparation on the offset substrate and thus prevents the deterioration of printing plates or forms. At the same time, a significant increase in the hydrophilicizing and activating properties of the preparations is achieved, thereby compensating for the shortcomings in the standard quality of natural colloids. Another advantage of using the preparations is the extension of the shelf life of the treated printing plates and forms.

Composition of the chemical preparation for preservation The resulting homogeneous solution is cooled and filtered.

Composition:

water sodium benzoate dextrin

1,2,3-propanetriol amido blau ethyl alcohol

684g 3g

280g g 0.03g 8g

The product is suitable for preserving aluminum and multi-metal printing plates and molds.

Example 2

The preparation is identical to example 1.

Composition:

water sodium benzoate dextrin arabic gum 1,2,3-propanetriol amido blau

707 3

220

20g

0.03g

The product is suitable for the preservation of anodically oxidized printing plates for high-cost rotary printing.

Example 3

The preparation is identical to example 1.

Composition:

water sodium benzoate dextrin polyethylene glycol amido blau isopropyl alcohol

679

280

0.03g 8g

The product is suitable for preserving aluminum printing plates and molds with electrochemical and mechanical treatment of the aluminum surface.

Example 4

The preparation is identical to example 1.

The surface treatment and activation of offset printing plates and forms is illustrated by the following practical examples.

Example 1

The individual components are dissolved in distilled or tap water, warm to 80 °C.

Ingredients: water 700 g sodium benzoate 3 g dextrin 280 g triethylene glycol 31 g starch blue 0.03 grams ethyl alcohol 8 g

The product is suitable for the preservation of trimetallic printing plates and molds with high costs.

Example 5

The individual components are dissolved in distilled or tap water, warm to 80 °C. After cooling and filtration, the preparation is ready.

for use. Ingredients: water 740 g sodium benzoate 2 g dextrin 220 g 1,2,3-propanetriol 5 g phosphoric acid (85%) 25 g ostazin red 0.02 grams ethyl alcohol 8 g

The product is suitable for activating and cleaning aluminum and multi-metal plates during their production or when used in a printing machine. Example 6

The preparation is identical to example 1.

Composition:

water 730 g sodium benzoate 2 g dextrin 220 g polyethylene glycol 10 g phosphoric acid (85%) 25 g ostazin red 0.02 g isopropyl alcohol 8 g

The product is used advantageously for cleaning and activating trimetallic offset plates and molds.

Claims (1)

Chemical preparation for the preservation and activation of the surface of offset printing plates and forms, characterized in that it consists of natural polysaccharides or their derivatives in a quantity of 2 to 60 parts by weight, polyhydric alcohols from the group 1,2,3-propanetriol, diethylene glycol, triethylene glycol and polyethylene glycols. 0.2 weight percent INVENTION up to 30 parts, 0.05 to 1 part by weight preservatives, 0.001 to 1 part by weight water-soluble dye, up to 10 parts by weight phosphoric acid, up to 5 parts by weight ethanol and isopropyl alcohol, and water by weight by weight 30 to 98 parts.