SU1497321A1 - Fibrous stock for making newsprint - Google Patents

Abstract

The invention relates to the pulp and paper industry and reduces the consumption of fibrous semi-finished products in the production of paper by reducing the mass of 1 m ^{2 of} paper to 40 g while maintaining its quality. The fibrous mass for the manufacture of newsprint contains the following components, wt.%: Groundwood 76-84

sulphite conifer unbleached cellulose 76-84

sulphate semi-glue pulp from larch wood 6-10. The pulp is prepared by blending groundwood pulp with a grinding degree of 72-76 ° SHR with sulfate semi-whitened larch wood pulp with a grinding degree of 24-28 ° ShR and sulfite coniferous unbleached pulp with a grinding degree of 24-28 ° ShR. 1 tab.

Description

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The invention relates to the pulp and paper industry.

The purpose of the invention is to reduce the consumption of fibrous semi-finished products during paper processing by reducing the mass of 1 m of paper to 40 g while maintaining its quality.

SUMMARY OF THE INVENTION The essence of the invention is that a pulp for making newsprint, containing groundwood pulp and sulphite softwood, unbleached pulp, additionally contains sulphate semi-bleached larch wood pulp. With the introduction of

The paper composition of two types of pulp simultaneously - sulfite conifer unbleached and sulfate semi-bleached larch wood, shows a synergistic effect on the discharge length indicator, i.e. the length of paper containing a mixture of these types of cellulose in the composition is 10-12% higher than the length of paper containing an equal amount of only one of the pulp types.

When grinding sulphate larch cellulose, the pulp forming properties of fibers occur

very quickly, and with a low degree of grinding (24-28 ° SH), a long-fiber mass is obtained with a good ability to form interfiber bonds.

Example 1. Newsprint pulp is prepared by mixing groundwood pulp (DMC) with a grind degree of 72- with sulphate semi-whitened larch wood pulp with a yield of 41.8%, ground in a laboratory roll to. degrees of grinding 24-28 ° СР, and with sulphite coniferous unbleached pulp, also ground in a laboratory roll to the degree of grinding 24-28 shR, with the following ratio of components, wt.%: DCM 76 sulfite unbleached pulp 14j ,

Newsprint samples are made of the composition.

40 + 0.5 g per known

weighing 1 m

method. Cast on a sheet machine, pressed on a roller press and dried on a LOA drying cylinder. Calendered, skipping samples placed between the sheets of the glazed press plate, between the shafts of the LOA roller press,

After conditioning, the finished paper samples at 65% relative humidity of the air are tested according to the state standards,

The results of the experiment are given in the table.

PRI me R 2, The sequence of operations is the same as in example 1. The difference is in the ratio of components in the prepared mass, namely, wt,%: DCM 84 sulfite unbleached cellulose 10j sulfate semi-bleached larch 6,

The results of the experiment are given in the table.

Example 3, the sequence of operations is the same as in example 1, the Difference is in the ratio of components in the prepared mass, wt,%: DKM 80j sulphite unbleached cellulose 12; sulphate semi-fiber from larch 8,

Example 4 (control). The sequence of operations is the same as in example 1. The difference is that the pulp is prepared with

0

five

0

zhana mi. DTM and sulphate semi-whitened cellulose from larch wood, beyond the limits specified in the formula, namely, wt.%: DCM 75; . sulphite unbleached cellulose 14; sulphate semi-sheeted larch cellulose 11,

Example 5 (control). The sequence of operations is the same as in example 1. The difference is that the paper pulp is prepared with the content of DTSM and sulphate semi-whitewashed pulp from larch, exceeding the limits specified in the formula, wt.%: DTSM 85- , sulfite unbleached cellulose 10; sulphate semi-sheeted larch cellulose 5,

0 Example 6 (control), The sequence of operations is the same as in example 1, The difference is that in the composition of the mass there is no sulphate semi-bleached cellulose from

5 / larch wood, and the content of sulfite unbleached pulp is equal to the maximum (total) amount of pulp specified in the formula, i.e., paper pulp of the following composition is prepared, wt.%: DCM 76; unbleached sulphite pulp 24.

Example 7 (control). The sequence of operations is the same as in example 1. The difference is that in the composition of the mass there is no sulfite coniferous unbleached cellulose, and the content of sulfate semi-whitened pulp from larch wood corresponds to the maximum. (total) amount of cellulose specified in the formula, i.e. preparing a paper pulp of the following composition, wt.%: DCM 76, sulphate semi-whitewash larch pulp 24

PRI me R 8 (control), the sequence of operations is the same as in example 1. The difference is that in the composition of the mass there is no sulfate semi-bleached larch wood pulp, and the content of sulfite unbleached pulp is equal to the minimum (total) amount of pulp specified in; The formula, t, e, is prepared for the pulp of the following composition, wt,%:. DCM 84j sulphite unbleached cellulose - 16,

Example 9 (control). The sequence of operations is the same as

five

0

five

and in example 1, the Difference is that in the composition of the mass there is no sulfite conifer, unbleached cellulose, and the content of sulfate semi-whitened cellulose from larch corresponds to the minimum (total) amount of cellulose specified in the formula, i.e. Prepare a paper pulp of the following composition, May. %: DCM 84i sulphate semi-gel of larch cellulose 16.

Example 10. The sequence of operations is the same as in Example 1. A paper pulp of known composition is prepared, wt%: DCM 70; sulphite conifer unbleached pulp 30.

Example 11. The sequence of operations is the same as in Example 1. A paper pulp of known composition is prepared, wt.%: DDM 74; sulphite conifer unbleached cellulose 26.

The results of the experiments are shown in the table.

From the data presented in the table it is clear that the replacement of part of sulto

fit unbleached pulp in the composition of the mass for the manufacture of newsprint on sulphate semi-white pulp from larch wood (examples 1, 2) allows, with the same total cellulose content in the composition (examples 6, 8), to increase the mechanical strength of the paper (breaking length and tear resistance), Its extensibility and whiteness. Compared to the known mass containing a greater amount of pulp as compared to the proposed one, the increase in the breaking length is 6.4%, the tear resistance is 2%.

A significant increase in strength, observed when using sulfite unbleached pulp together with sulfate semi-bleached pulp from larch wood, gives rise to it is possible to reduce the total cellulose content of the composition by 6-10% compared to the known weight and at the same time reduce the weight of 1 m of paper to 40 g while maintaining the indicators of mechanical strength, optical and printing properties, at the required level.

497321Ь

. The possibility of preserving a larger proportion of DDM in the composition of the mass, resulting from the use of a smaller total amount of cellulose as a mixture of sulphite coniferous unbleached and sulphate semi-whitened larch wood pulp, compensates for the negative effect of larch cellulose on the printing properties of the paper and provides the required level opacity and printing properties of paper; This is confirmed by the data in the table; the color perception of paper made from the mass of the proposed composition is practically no different from the color perception of paper made from a known mass, and

20 prologie impression is even lower than that of paper from a known mass.

The increase in the content of sulfate semi-bleached pulp from larch wood in the composition of the mass above

25 10% (example 4) or using it in an amount less than 6% (example 5) is impractical, since in the first case there is a noticeable decrease in opacity and deterioration of printed

30 properties; in the second, the desired results for increasing the tearing resistance of the paper are not achieved.

Claims (1)

Invention Formula Pulping mass for making newsprint containing groundwood pulp and sulphite softwood unbleached pulp, characterized in that, in order to reduce the consumption of fibrous semi-finished products when making paper by reducing the weight of 1 m of paper to 40 g while maintaining its quality, the mass additionally contains sulfate semi-white pulp from larch wood in the following ratio of components, wt.%: Groundwood wood 76-84 Sulfite conifer unbleached cellulose 10-14 Sulfate semi-bleached cellulose larch wood 6-10 Weight I m, g Density, g / cm Voaduhoproni, ml / min. Fracture length, m I Contrast hHto, 1hN. Extension for stretching, Z Whiteness, J Non Transparent pCTb, I CRYASKOVOSPRI-Yatie, D "Prosyachnva-imen - npoOif vani red-" 40 4d404040404040404040 0,600.0,582О, WO0,6000,582.0,6040,5780,5920,5600,6190,6Т4 305 3033073073032873362883t6280290 3490 3250ЗЗБО35203200311031902970.308032803180 208192 1,571.41 58,758,7 , 93,394.3 1.13 1.13 0,330.31 200 210 182 193 211 178 193,204 195 1,511,601,381,371,541,251,45Г, 431.38 58,758,758,656,260,157,259.8 55,355.9 94,092,994,794,992,495,393,794,194,6 1,131,121,131,141,101,131,111,151, | 4 0.32Oj340,310,370,350,340,340,410,38 211 178 193,204 195