CS249204B1 - Cardboard for corrugated board's cover layer - Google Patents

Abstract

The solution to the production of cardboard from unbleached sulphite pulp and recovered paper. Its essence is that it is neutral Suffit pulp consists of coniferous, of hardwoods and hardwoods and in a certain ratio are deciduous trees to coniferous and poppy to hard deciduous trees, with a ratio of unbleached sulphite pulp to the pulp from the waste paper in the total mixture is 1: 9 to 9: 1, preferably 3: 2 to 2: 3. The pulp is prepared in a boiling solution containing an anthraquinone-type catalyst or derivatives thereof. The solution is in the field of cardboard production.

Description

It is an object of the present invention to provide a carton for a corrugated board liner.

Until now, sulphate coniferous unbleached pulp has been used to produce cardboard. A blend of non-bleached kraft pulp and waste paper was used in the manufacture of a lower alkali grade carton.

Cardboard according to the author's certificate No. 217 670 consists of three components, namely pulp or semi-pulp, made of wood chips with a content of 20 to 80% by weight. poppy broadleaf and 80 to 20 wt. hardwood, unbleached kraft pulp and unsorted waste paper with a total component ratio of 2: 1: 2 or 2: 2: 1.

A disadvantage of such a carton manufacturing process is the use of unbleached kraft pulp, which has recently become deficient.

A further necessity of this carton production is the fact that a separate grinding line is required for the processing of kraft unbleached pulp and a high power consumption is required for grinding this pulp to achieve the desired degree of milling SR.

These disadvantages are overcome by the invention which comprises neutral sulphite pulp and waste paper pulp, the neutral sulphite pulp being a mixture of soft, hard, deciduous and coniferous trees, the ratio of coniferous to deciduous trees is 9: 1 to 1: 9, the proportion of hard deciduous trees and poppy deciduous trees in the mixture of deciduous trees is 1 to 99% by weight. % to 99 to 1 wt. preferably, the ratio of coniferous to broadleaved trees is 7: 3 to 3: 7, the proportion of hard broadleaves and soft broadleaves in the broadleaved mixture is 60: 40% by weight. % to 40: 60 wt. and the ratio of the pulp to the recovered paper pulp in the total mixture is 9: 1 to 1: 9, preferably 3: 2 to 2: 3.

Recovered paper consists of a mixture of kraft paper pulp, corrugated cardboard and mixed collection. The neutral sulphite pulp is prepared in a discontinuous or continuous digester wherein the cooking solution contains anthraquinone-type catalyst or derivatives thereof in an amount of 0.05 to 0.5% by weight. for absolute dry wood.

The advantage of carton for corrugated liner cover is that it contains technical parameters at the level of cartons made from separate kraft unbleached pulp, or from a mixture of kraft unbleached pulp and kraft waste paper. The neutral sulphite pulp produced by the above process and the pulp made with recovered paper can be used for the production of single-layer (simplex), double-layer (duplex) or multi-layer cover cartons.

Example 1

Of pulp prepared from a mixture of chips, 70% by weight. of hard and poppy deciduous plants in a ratio of 1: 1 and 30 wt. coniferous trees (spruce) by a neutral sulphite boiling process, which have been delignified, with an alkali load of 17.8% sodium oxide and a ratio of sodium sulphite to sodium carbonate of 5: 1 to absolute dry wood, in the presence of anthraquinone catalyst in an amount of 0.18 ° % by weight, for an absolutely dry wood in a 67% yield discontinuous reboiler and P6 waste paper, a 70% w / w stock of neutral sulfite pulp and 30% waste paper was prepared and each component was milled separately to the final stage milling for pulp to 27 degrees SR and for waste paper to 31 degrees SR.

For hydrophobization, the pulp was sized with the addition of a dispersed, reinforced sizing agent FURTIN LUL-50 and a concentration of 50% in an amount of 0.8% by weight. % and aluminum sulfate in an amount of 1.7 wt. on time and paper pulp. After leveling, the paperboard was made by single-layer molding with a cover card of 125 g / m ² with the following physical-mechanical parameters:

market length:

- only 7.4 km - over 4.2 km overpressure strength:

505 kPa Tear strength:

- only 1 420 rnN - across 1 780 mN across the annular bracing strength at 12,7 mm tape width:

200 N.

The production of the corrugated cardboard covering sheet of Example 1 was carried out on an experimental paper machine.

An advantage of the process of Example 1 is that the physico-mechanical properties of the carton produced have a K-0 quality level, with the furnish composition being two-component, without the need for kraft unbleached pulp.

Example 2

From pulp prepared from a mixture of chips, by weight of hard and poppy deciduous plants in a ratio of 1: 1 and 50 wt. coniferous trees (spruce) by a neutral-sulphite boiling process, which were delignified at 17% alkali and at a ratio of sodium sulphite to sodium carbonate of 5: 1, to an absolute dry wood in the presence of an anthraquinone type catalyst of 0.2% wt. For absolutely dry wood by batch batching, with a 69% yield and P6 grade waste paper, pulp was prepared for the production of double-layer cartons (duplex) as follows:

(a) topsheet:

was prepared from paper pulp containing 100% loading of neutral-sulphite pulp ground to a grinding degree of 33 ° SR and granulated by adding 0.5% by weight of a reinforced paste size OULU. and aluminum sulfate in an amount of 1.4 wt. for absolutely dry pulp.

(b) bottom layer:

was prepared from pulp containing 37,5% neutral sulphite pulp and 62,5% pulp grade P6 paper, each bare ground separately as follows: pulp ground at 21 ° SR and waste paper ground 28 ° SR.

The pulp sheets prepared for the top and bottom layers were formed on a twin-run papermaking machine with a secondary inlet of a total weight of 150 g / m ² , the top layer having a basis weight of 40 g / m ² and the bottom layer having a basis weight of 110 g / m 2 ² . The produced double-layer cover board (duplex) had the following physico-mechanical parameters:

market length:

- just 8.6 km - over 4.9 km overpressure strength:

620 kPa tear strength:

- only 1 520 mN - transversal 1 900 mN annular cross-strenght at 12,7 mm width:

260 N absorbency for top layer in one-sided wetting in 60 sec (Cobb60):

g / m ² .

An advantage of the produced carton according to Example 2 is that the carton provides high smoothness of the topsheet, higher whiteness (43 percent MgO), giving the possibility of improved printability.

Example 3

From pulp prepared from a mixture of 95% % coniferous spruce chips and 5 wt. poppy and hard broadleaves in a 1: 1 ratio, by a neutral-sulphite boiling process, which were delignified at 18.5% sodium oxide and at a 5: 1 ratio of sodium sulphite to sodium carbonate to absolutely dry wood in the presence of anthraquinone type 0 catalyst %, 2 wt. , for absolutely dry wood in a laboratory cooker with a pulp yield of 68.1%, the pulp was prepared by grinding to a grinding degree of 26 ° SR in a laboratory Holland. The test sheets, made on a laboratory hatchet, exhibited the following physico-mechanical values at a surface weight of 100 g / m ² :

- market length 13.0 km - overpressure strength 720 kPa - tear strength 745 mN - two bends 1,750

Claims (4)

SUBJECT 1. Cardboard for a corrugated cardboard sheet of neutral-sulphite pulp with a yield in the range of 60-75% and waste paper pulp, characterized in that the neutral sulphite pulp consists of a mixture of soft-leaved hardwoods, hard hardwoods and coniferous woods, wherein the ratio of conifers to deciduous trees is 9: 1 to 1: 9, the proportion of hard deciduous trees and poppy deciduous trees in the mixture of deciduous trees is 1 to 99% by weight. % to 99 to 1 wt. and the ratio of the pulp to the recovered paper pulp in the total mixture is 9: 1 to 1: 9. 2. Cardboard for the corrugated cardboard covering of point 1, characterized in that the ratio of conifers to deciduous trees is 7: 3 to 3: 7, the proportion of hard deciduous trees and poppy deciduous trees in the mixture of deciduous trees is 60: 40% wt. % to 40: 60 wt. and the ratio of the pulp to the recovered paper pulp is 3: 2 to 2: 3. 3. Cardboard for corrugated cardboard according to items 1 and 2, characterized in that the waste paper pulp is composed of a mixture of kraft paper pulp, corrugated paper and mixed collection. 4. Cardboard for corrugated cardboard, according to claim 1, characterized in that the pulp is prepared in a boiling solution containing an anthraquinone type catalyst or its derivatives in an amount of 0.05 to 0.5% by weight. for absolutely dry wood.