SU560024A1 - The method of producing hemicellulose - Google Patents

Description

The aim of the invention is to obtain hemicellulose from hardwood and coniferous chips, which are easily separated after warping when dividing into fibers, which have increased strength in wet sakuppi and increased belpzna.

This is achieved by the fact that wood chips, hardwood, coniferous, or their mixture, are steamed for b-10 min at 9 °-JuoC. To remove moisture p air from the chips of its srcma major to 2: 1, 2, oa: 2, o: 1. Then crawl i) oip1b1vayu1- heated urinary solution (io impregnation temperature oO-8U Cj for / -2U min, input 15% of urine by weight asolyutic dry weight of the cheek.

The soaked wood chips boil with steam; Sulfuric acid or its aqueous solution in the amount of 4-15% SO2 based on the mass of absolutely dry fiber is introduced into the warp zone. Cook t for 15-4U min npii Ibb-180 C. After cooking, the chips are ground on a disk.

Example 1. Chips - a mixture of birch and spruce 1: 1. After the niohiaping agent, a solution of urea chips, containing 13% of urea from a mass of absolutely dry chips, is served for cooking. In steam and gas boiling, 10% bU2 is added by weight of absolutely dry chips. Variation in 41) mission. After one pass of the welded cheeks through the Spout-Waldron disk mill, the grinding was 32ShR. Output B1, about% by weight of absolutely dry chips, taken to the boil.

Indicators of mechanical gravity: Durability, m9100

Squeezed, kg / cm - 5.0

Contrast to fracture (number

Double HepernOoBj210

Tearing resistance, g 130 11 Wetness in the wet state, m72 Whiteness, units white53 Example 2: Chips - a mixture of birch and spruce 1-1. Chips after proparkp impregnation with a solution of urea contains 5% of urea by weight of absolutely dry chips. 4% SO2 from the mass of absolutely dry glands in the form of a solution is introduced into the steam-gas cooking zone, boiled for 15 minutes at 175 ° C. Pass through the Cyrouth-Galdron disk mill 2 times. The milling weight of the mass is. Output 82.7% by weight of absolute dry chips. Indicators of mechanical strength: Fracture length, m7600 Prodavlpvanie, kg / cm 4,3 Resistance to fracture (number

double peregpbov) 140

Tearing resistance, g 115 Wet strength, m68 Belpsia, units white53 EXAMPLE 3. Chips - 100% birch. Chips coming to cooking contain 5% of urea by weight of absolutely dry uj, enbi. SOs in the amount of 10% of the mass of absolutely dry cheye is introduced into the steam and gas zone. Var t

iri 165 ° C for 30 min. The degree of grinding 2USCHR. Output 87.0% by weight of absolutely dry cheek.

Indicators of mechanical strength; Breaking length, m8850

Co-ordination and productivity, kg / cm 4,9

Concurrent fracture

double kinks) 160

Tear resistance, 120 g

Durability in a wet state, m70,2

White, units white57

Example 4 (for comparison). Schena - a mixture of elp and birch. Cooking monosulfne. The consumption of chemicals for cooking amounted to 6.5% in terms of NajO by weight of absolutely dry cheek. Cooking hemierature 170C, duration 30 min. After boiling the chips, 6 times are passed through a Sprout-Waldron disc mill. The degree of grinding 30 ° W. Output 82.1% by weight of absolutely dry cheek. Mechanical accuracy indicators:

Breaking length, m5400

Burst resistance, kg / cm 3,2

Co-motivation is: 1y (number

double kinks) 50-70

Wet strength, m32

White, units white46

Resistance to tearing, g 80 According to qualitative standards (irocnosti and whiteness) iolcellulose, obtained according to the proposed syosob, is signifi cantly better than my sulfate and iolucellulose iri in the same way :; output from the mass of absolutely dry chips.

The use of this type of pulp in the production of paper can reduce the consumption of more expensive unbleached pulp.

The advantage of the offer: The South way of obtaining cellulose is the simplicity and prepared cooking solutions; The elimination of metal bases simplifies the regeneration of chemicals from spent liquor, and to a lesser degree the environment is polluted.

Some ways of processing for deciduous and spruce wood processing.

The wetting mass has a high durability in the wet state, which makes it possible to work at higher speeds of the papermaker on the machine.

The production of hemicellulose mass is reduced by the energy costs of grinding (in terms of mono-sulfite). Higher strength and whiteness (as compared to monosulfite) expands the range of papers in which semi-cellulose obtained using the proposed method can be used.

The use of urea (and other organic substances) instead of metal cores is promising, since organic substances can be obtained synthetically.

Claims (2)

1. A method of producing hemicellulose by impregnating the wood pulp, boiling in the vapor-gas phase, followed by mechanical separation into fibers, characterized in that, in order to increase the strength of the target product, the wood chips are impregnated with urea solution at a rate of 5-15% by weight of absolutely dry fibers, and cooking in the vapor – gas phase is carried out for 15–40 min in the presence of sulfurous anhydride at its consumption of 4–15% by weight of absolutely fiber. 2. Method no. 1, about tl and h and y and with the fact that cooking in the vapor phase is carried out at 165-180 ° C. Sources of information taken into account and expertise: 1. Pateit USSR X 257392, cl. D 21 C 3/04, 1967. 2. US Patent To 3532594, 162-19. 1970.