SK2495A3 - Method for discolouration of waste paper by surface active substances - Google Patents

Abstract

This patent describes the procedure closed to the deinking the collected paper with the use of surface active substances, where the collected paper is defibred in water and the mixture of the above mentioned surface active substances, together with 3 up to 25 moles of ethylene oxide, in a quantity 0,08 up to 0,55 weight percent related to stock, or alkylester of saturated or unsaturated fat acid C18, or oxyethyl alkyl phenol is added to this suspension, in the ratio closed to the value of 30 up to 50 : 70 up to 50 weight parts before the defibering is provided, and the released parts of printing colour are removed, with the use of the flotation, after the homogenisation and dilution of the suspension was provided however these surface active substances are prepared based on the condensates closed to the fat alcohol C12 up to C18.

Description

Technical field

The invention relates to a method of lightening with surfactants.

waste paper

BACKGROUND OF THE INVENTION

Basically, waste paper illumination is a separation process that uses chemicals, heat, and mechanical energy to remove ink particles and toners from secondary fibers. The choice of equipment and chemicals for the lightening process determines the type of ink and the method of printing waste paper. It primarily controls the size of the ink particles to be removed from the fibers. Large ink particles are removed by sieve and centrifugal screens, and small particles are scrubbed. Flotation removes those particles that are too small to remove by sorting and too large to wash C Shrinath A. Szewczak J.T., Boven I.J .. Tappi 74, 7, 85-93, 1991). These are 10 to 150 µm particles. Chemicals are added to the flask. flotation and washing.

In the prior art processes for lightening waste paper containing wood pulp paper, such as newsprint, 0.8-1.5% NaOH, 0.5-2.0% H2O2 are added to the rollers. 1.0 to 3.0% sodium silicate and 0.15 to 0.4% chelating agent to a 5 to 15% fiber suspension, per a.s. fiber) at a temperature of 45-55 ° C to release the ink particles and avoid redeposition to the fibers (Ferguson L.D., Tappi 75, 7, 75-83, 1992). Each chemical has a specific function. In the subsequent flotation, 0.25-1.5% of a suitable surfactant should be added so that the released ink particles entrained by air bubbles float to the surface and are separated from the lightened pulp by wiping. These are generally fatty acid soaps and more recently also wood and resins etherified with ethylene oxide such as formaldehyde phenol and copolymers of ethylene oxide and propylene oxide based on fatty acids and their diamines. It is often a mixture of substances that can already be added to the roll-up. The disadvantage of these procedures is. whereas it is necessary to determine for each lightened fiber the optimum quantity of individual chemicals and surfactants, while respecting their interactions and their cost / effect relationship. For example, silicates greatly increase the efficiency of cost-intensive hydrogen peroxide, but their use raises problems with the formation of deposits and deposits on the apparatus. sieves and felts.

SUMMARY OF THE INVENTION

The above-mentioned disadvantages are overcome by the method according to the invention, the essence of which is that. by collecting the recovered paper in water and treating the roll-up slurry containing 1 to 15% by weight, the recovered paper in water is treated with a mixture of surfactants based on C12-C18 fatty alcohol condensates with 3 to 25 moles of ethylene oxide in an amount of 0.08 to 0.55% materials, or the fiber mixture is added to the alkyl ester of saturated or unsaturated fatty acid or Target oxyethylated alkylphenol in the proportions ^30-50: 70-50 parts by weight of the particles and the released inks, after homogenisation and dilution of the slurry to the flotation and ou.

The mixture of substances can also be added directly to the pulping of the waste paper and float the diluted suspension after dilution.

The lightening effect of this process compared to the process using a mixture of chemicals such as NaOH, H2O2. Sodium silicate, chelating agent and in the subsequent flotation soap is higher, achieved at room temperature using a small amount of substances readily biodegradable and without the problems caused by the use of silicate.

The method of lightening waste paper is exemplified by examples not specifically covered by this method.

Examples

Example 1

A suspension of 50 g of newsprint and 50 g of magazine waste paper in 5 L of water is stirred for 30 min. 100 ml of an aqueous solution containing 0.1 g of condensates of synthetic C12-C15 alcohols with 4.5 to 13 moles of ethylene oxide and 0.05 g of isobutyl oleate are added to the pulped suspension, and after 10 min homogenization, 5 l of water are added and the ink particles released are removed by flotation. The fiber is lightened by 08¾ IS0.

The process of lightening the same mixture of waste paper with the addition of a mixture of chemicals consisting of 1% NaOH, 1% H2O2. 2% Na 2 S ^{2 O 3} and 0.3% chelating agent until pulping at 40 ^° C and with the addition of 0.5% soap (wt%, per pulp) in the subsequent flotation, the pulp is lightened by 7% ISO.

Example 2

To a mixture of 65 g magazine and 35 g newsprint is added 5 liters of water and 100 ml of an aqueous solution containing 0.065 g of C12 to C15 fatty alcohol condensates with 3 to 25 moles of ethylene oxide and 0.065 g of oxyethylated nonylphenol. water and loose ink particles are removed by flotation. The fiber is lightened by 08¾ IS0.

Industrial usability

The method of the invention can be used to remove ink from newsprint and magazine paper.

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Claims (2)

PATENT CLAIMS What is claimed is: 1. A method of lightening waste paper with surfactants, characterized by. by recovering the recovered paper in water and treating the wound slurry containing 1 to 15% by weight, the recovered paper in water is treated with a mixture of surfactants based on C12 to C18 fatty alcohols with 3 to 25 moles of ethylene oxide in an amount of 0.08 to 0, Saturated or unsaturated C18 fatty acid alkyl ester or oxyethylated alkylphenol is added to the fiber or to the mixture in a proportion of 30 to 50 = 70 to 50 parts by weight and the released ink particles are removed by float after homogenization and dilution of the suspension. 2. A method of lightening waste paper with surfactants according to claim 1, wherein the mixture of surfactants based on condensates of C12-C18 fatty alcohols with 3 to 25 moles of ethylene oxide is used in an amount of 0.08 to 0.55% by weight. on fiber or with the addition of an alkyl ester of a saturated or unsaturated C 18 fatty acid or with the addition of an oxyethylated alkylphenol, in a ratio of 30 to 50-70 to 50 masses, added directly to the pulping.