RU2472891C1 - Method to restore missing parts of paper sheets - Google Patents

Abstract

FIELD: textiles, paper.

SUBSTANCE: for restoration paper sheets they are prepared, pulp with a binder is prepared, pouring of the pulp with the binder on the missing parts of the sheet, and drying the sheet. At that, as a binder, bacterial cellulose is used cultured by strain Acetobacter xylinum B-880 of All-Russian collection of microorganisms, in the amount of 2-6% by weight of oven-dry softwood sulfate bleached pulp. After pouring the sheets are dried at a temperature of 80°C. Seam strength remains at high level after 12 days of artificial thermo-humid at a temperature of 80°C and humidity 65%.

EFFECT: method enables to improve the seam strength between the compensative part and the restored document.

3 cl, 2 tbl, 8 ex

Description

The invention relates to methods for recovering the missing parts of paper sheets during the mechanized restoration of books, maps, prints, newspapers, manuscripts and archival materials by the method of replenishing the lost parts of the sheet and is intended for use in the practice of large book depositories, archives and in the pulp and paper industry.

Currently, most large restoration divisions in the world have equipment for mechanized restoration by adding to the lost parts of sheets of documents. One of the disadvantages of the method is the low strength of the seam between the old and the replenished part of the sheet. To strengthen the seam in the paper pulp, you can enter various binders.

CA patent No. 1,279.450 describes a method for using bacterial cellulose as a binder for the production of non-woven and paper-like materials from various fibers, including from fibers of plant origin. The optimal amount of bacterial cellulose introduced into the mass was determined - 20%. A method for cultivating bacterial cellulose under dynamic conditions is also claimed. However, this patent did not investigate the effect of bacterial cellulose additives on the strength of the joint between the old and the replenished part of the sheet during mechanized restoration of documents and the effect on the strength of the joint of accelerated warm-wet aging.

In this application, bacterial cellulose, proposed for use as a binder in a paper pulp for mechanized restoration of documents, is obtained by surface cultivation of a strain of Gluconacetobacter xylinus BKM B 880. Nanogel-film of bacterial cellulose (NGPC GX) was obtained on nutrient media containing carbon source waste or semi-waste of production having a monosugar, for example, a wood hydrolyzate or liquor of pulp and paper production (patent RU No. 2189394, publ. September 20, 2002). The method is implemented on a model plant for the production of NGPTs GX.

The closest in technical essence and technical result is a method of restoring the missing parts of sheets of paper (A.S. No. 1151635, Pub. 23.04.85, Bull. No. 15), including the preparation of restored sheets, the casting of the pulp with a binder on the missing parts of the sheet, pressing and drying with simultaneous dissolution of the binder, while polyvinyl alcohol fibers are used as the binder. Known additive provides increased productivity of restoration work while maintaining the quality indicators of the sheets. However, the known method requires a special mode of pressing and drying paper for swelling and dissolving polyvinyl alcohol fibers. In addition, polyvinyl alcohol fibers as a binder have proven themselves when introduced into paper pulp only from cotton pulp in an amount of not more than 10% by weight of cellulose fiber (Blank M.G. Polyvinyl alcohol fibers as a binder in mechanized paper restoration // Theory and Practice of Book Preservation in the library, issue 6, L, GPB, 1974, pp. 87-105.)

The technical task and the positive result of this method is to increase the mechanical strength of the seam between the document and the replenishing part when using pulp of sulphate bleached softwood pulp, stability of the strength of the seam during artificial heat-wet aging, as well as eliminating the pressing process and simplifying the drying process of paper.

This task and a positive result are achieved due to the fact that the method of restoring the missing parts of the paper sheets includes preparing the restored sheets, preparing the pulp with a binder, casting the pulp with a binder to the missing parts of the sheet and drying the sheet, characterized in that to increase the strength of the seam between the bacterial cellulose cultured with the Gluconacetobacter xylinus BKM B 880 strain in an amount of 2-6% by weight of abs understood softwood kraft dry bleached pulp. The method is characterized in that the NHPC GX is preliminarily dissolved for 100-120 minutes, followed by grinding: refining grinding 20-30 minutes, chopping 1-3 minutes at a concentration of 0.2%.

The implementation of the proposed method for recovering the missing parts of sheets of paper is illustrated by the following examples of its implementation.

Example 1-8. The paper pulp is prepared in the following way: sulfate bleached softwood pulp is dissolved and milled to 35 and 45 ° C, then the prepared CGX is added to the ground pulp in an amount of 2-6% by weight of absolutely dry fiber, mixed for 10-15 minutes and used for topping up the missing parts on the ROM-4 restoration machine. CGX is subjected to dissolution for 100-120 minutes, followed by grinding (refining grinding for 20-30 minutes and chopping for 1-3 minutes). Dissolution and grinding is carried out at a concentration of 0.2%. As model samples of documents for restoration, sheets of a book from the beginning of the 20th century were used. from sulphite pulp and sheets of the document of the first half of the XIX century. from rag half mass. The pre-treated restoration sheets are laid on a grid, the mass is fed with a fibrous binder, and vacuum casting is performed. At the same time, as a result of water filtration through the grid, the fibers fill the unoccupied sections of the grid. Then the cast sheet is dried at a temperature of 80 ° C (sparing mode for documents).

The results of determining the strength of the seam between the restored document and the replenishing part are presented in table 1.

Table 1 The strength of the seam between the restored document and the replenishing part Indicators Examples No. 1 Number 2 Number 3 Number 4 Number 5 Number 6 Number 7 Number 8 Basis of composition Sulphate bleached softwood pulp (35 ° C) Sulphate bleached softwood pulp (45 ° C) Type of additive TSGX TSGX Amount of Additive 0 2 four 6 0 2 four 6 Destructive force of a seam with sheets of a document of the beginning of the XX century, N 1,5 3,7 4.0 4.0 3,5 6.0 6.2 6.2 The destructive force of the seam with the sheets of the document of the beginning of the first half of the XIX century., N 9.5 15,5 16,0 16,0 11.0 18.7 19.5 20.5

Analysis of the experimental results presented in table 1 shows that the introduction of UGX in the composition of the paper pulp for mechanized restoration of documents (examples 1-8) helps to increase the strength of the seam between the filled and filling parts of the sheet of the document. So, when the content of CGX in the amount of 2-4% in the composition of the paper pulp, the strength of the seam during restoration of the document of the beginning of XX century increases by 2.5-2.7 times (examples 2, 3) and 1.7-1.8 times (examples 6, 7), with the restoration of the document beginning of the first half of the XIX century. - 1.6-1.8 times (examples 2, 3, 6, 7).

To study the stability of the weld strength during storage, the samples were subjected to artificial heat-wet aging in a TABAI chamber. The aging regime was in accordance with ISO 56-30: 1986 “Paper. Cardboard. Accelerated Aging (4.3). "Wet heat treatment at a temperature of 80 ° C and a relative humidity of 65%." Artificial aging was carried out for 12 days. The test results are presented in table 2.

From table 2 it is seen that the strength of the seam between the replenishing part containing additives, CGX and the document after 12 days of warm-wet aging remains higher (examples 2-4, 6-8) than with the replenishing part, not containing additives CGX (examples 1 , 5).

table 2 The strength of the seam between the restored document and the replenishing part after 12 days of artificial heat-wet aging Indicators Examples No. 1 Number 2 Number 3 Number 4 Number 5 Number 6 Number 7 Number 8 Basis of composition Sulphate bleached softwood pulp (35 ° C) Sulphate bleached softwood pulp (45 ° C) Type of additive TSGX TSGX Amount of Additive 0 2 four 6 0 2 four 6 Destructive force of a seam with sheets of a document from the beginning of the XX century, N 1,0 2.0 2.0 2.2 2,5 3,5 3,5 3,5 The destructive force of the seam with the sheets of the document of the beginning of the first half of the XIX century., N 7.5 11.0 12.5 12.5 8.5 15.0 15.0 16,0

Claims (3)

1. The method of restoring the missing parts of the paper sheets, including preparing the restored sheets, preparing the pulp with a binder, casting the pulp with a binder into the missing parts of the sheet and drying, characterized in that to increase the strength of the seam between the filling part and the restored sheet of the document as a binder use bacterial cellulose cultured with a strain of Gluconacetobacter xylinus VKM B-880 in an amount of 2-6% by weight of absolutely dry bleached bleached softwood pulp. 2. The method according to claim 1, characterized in that the bacterial cellulose is subjected to preliminary dissolution for 100-120 minutes, followed by grinding: refining grinding 20-30 minutes, chopping 1-3 minutes at a mass concentration of 0.2%. 3. The method according to claim 1, characterized in that the complex: the restored sheet plus the replenishing part is subjected to artificial heat-wet aging at a temperature of 80 ° C and a humidity of 65% for 12 days, after which the strength of the seam is checked.