SU699068A1 - Pulp preparation method - Google Patents

Description

(54) METHOD OF PREPARATION OF PAPER MASS 36 The ratio between acid and Na CMC varies depending on the degree of substitution of Na CMC and the type of acid (s) in the range of 0.003 to 0.011 kg-ccv acid / kg Na CMC. For the most common industrial brands Na CMC with a degree of substitution of 6080, the ratio between acid and Na CMC is preferably chosen in the range of 0.0034 to 0.0075 kg-eq of acid / kg of Na CMC. The concentration of Na CMC in the solution should be maintained in the range of 1-30%, since the concentration is higher Na CMC interferes with its uniform acid propelling. lower concentration (less than 1%) of the solution leads to a significant increase in the duration of treatment. The preferred concentration region of Na CMC in solution (depending on the type of Na CMC and modifying acid) and the most common Na CMC species with a degree of polymerization of 300-600 should be 5-15 wt.%. The time of modifying the treatment of Na CMC varies depending on its concentration in the modifying solution, the ratio between the acid and Na CMC, the type of Na CMC and acid, but under all these conditions it should decrease for at least 5 minutes. The preferred treatment time for Na CMC for the most common types of Na CMC and, subject to other recommended conditions, should be min. The Na-CMC thus treated is loaded into a grinding device, for example, roll together with cellulose and grind in the selected mode until the desired degree of grinding is achieved. The mass thus prepared is diluted to the desired concentration and, in usual order, auxiliary filler substances, sizing agents, coagulants are added to it, adjusting the pH of the pulp to 3.8-5.0, preferably 4.4-4, 8, the paper is cast, which after drying and calendars 1 has a high density and mechanical strength. Examples of pulp consisting of 100% bleached cellulose brand Photo with a concentration of 2% were introduced: option 1 - Na CMC in the form of a powder at the rate of 2.5% by weight of absolutely dry fiber (according to the prototype); Option 2 - 4% Na CMC solution at the rate of 2.5% by weight of absolutely dry fiber; option 3 - carboxymethylcellulose sodium salt was treated with 10% sulfuric acid solution, taken in the amount of 0.006 g-eq per 1 g of Na CMC; Na-CMC treatment with an acid solution was carried out for 20 minutes at a pH of 0.6, then modified Na-CMC was introduced into the pulp in an amount of 2.5% by weight of absolutely dry fiber; Option 4 - the additives were not introduced into the pulp. All four variants of the prepared mass were ground to 35-37 ° IlIP. Further, in each of the four options was introduced completely, saponified glue from gum rosin in the amount of 1% by weight of absolutely dry fiber. After 10 minutes of transfer, an aluminum sulfate solution was injected at the rate of 3% by weight absolutely: dry fiber. Then, a paper weighing 100 g / m was cast on a sheet cutting machine. Samples were conditioned at a humidity of 65% and a temperature of 20 ° C. The test results of the castings are given in table. 1. Table 1

/, E7o powder 1ч lmts from the weight of absolutely dry fiber

2.5% Na CMC solution by weight of absolutely dry fiber

2.5% Na CMC, treated sulfuric acid

Paper weight, ground without additives

14

3610

15

3640

eleven

3900

sixteen

3420

From tab. 1, it is clear that the increase in mechanical strength (fracture resistance, increase in breaking length) with the addition of Na CMC before grinding is observed in the third variant, in which Na CMC was pretreated with acid.

Example 2. In the fibrous mass consisting of 100% bleached cellulose brand Photo with a concentration of 1% was introduced:

Option 1 - Na CMC in the amount of 2.5% by weight of absolutely dry fiber. Na CMC was pretreated with a 10% solution of oxalic acid, taken in an amount of 0.006 g-eq of oxalic acid per 1 g of Na CMC for 20 minutes at pH 2.0;

Option

2.5% Na CMC, modified for 20 minutes

2.5% Na CMC, modified 5 min.

2.5% Na CMC, modified for 3 minutes

From tab. 2 shows ado decrease in reggae. the treatment of Na CMC with acid from 20 min to 5 min insignificantly impairs the quality characteristics of the paper produced, and at the same time, a further reduction in the modification time dramatically reduces the achievable strength level, which makes it possible to establish the lower limit of Na CMC acid processing time in 5 min. At the same time, it can be noted that the modification of Na CMC of oxalic acid for 20 minutes, i.e. under conditions identical to example 1 (option 3) gives a paper that is very similar in properties to paper obtained at low tide in example 1 (option 3). -Last indicates the interchange between the organic and inorganic acids in the proposed method.

Example 3. A photo mass was introduced into a fiber mass consisting of 100% cellulose brand: Na CMC, pretreated for 20 minutes with a mixture of acids, including 0.003 g-eq of phosphoric acid and

option 2 - Na CMC in the amount of 2.5 :; by weight of absolutely dry fiber, modified according to option 1 for 5 minutes;

option 3 - Na CMC in the amount of 2.57 g by weight of absolutely cjocoro fiber, modified according to option 1, for 3 minutes.

Three variants of the mass were ground, glued to pH 4.5 ,. cast, pressed and dried under conditions identical to example I. Three variants of the obtained paper weighing 100 g / m after; air conditioning at 65% air humidity and temperature of 20 ° C was tested for various parameters. The average of 10 castings are given in table. 2

Table 2

Absorbability

Break the war one-sided, wetting it on the device OS-2 in water for 30 s g / m

13.0

3930 14.0

3890 14.0

3640

0.003 g-eq of formic acid per 1 g of Na CMC, taken in the form of 10% aqueous solutions. The process of modifying processing goes with

pH 1

The process of grinding, sizing to pH 4.2, grinding and drying the reflux of the suspension obtained in this way was carried out under conditions identical to example 1. During the tests, the castings obtained in this way had the following indicators: fracture resistance (the number of double bending) - 1120, breaking length of 38SO m and Absorbability at one-sided immersion in a BOJ for 30 s - 12 g / m.

As can be seen from. of example 3 and the results given in example 1, the use of a mixture of acids for the modifying treatment of Na CMC, while observing the modification regime, also leads to rather high results.

Example 4: To select the minimum acceptable amount of acids for treating the CMC fibrous suspension with double translations of the proposed method.

The process of casting wedzt example 1.

For grinding, 3 variants of a fibrous suspension prepared by composites of 100% bleached sulfite A-11 cellulose were prepared. In the first batch, 1.5% Na CMC (in terms of absolutely dry matter from the mass of cellulose) was injected, which is tentative. 0.003 g-eq. HNOZ per 1 g of NaKM in the form of an 8% aqueous solution for 45 min. The process of modifying treatment with acid is at a pH of about 2.0.

In the second version, the fibrous suspension was injected with 1.5% Na CMC (in terms of absolutely dry matter by weight of cellulose), KOTOpjTo was pretreated with I

1.5% Na CMC modified with 0.003 g-eq HNOj

1.5% Na CMC modified with 0.0015 g-eq HNOj

1.5% Na CMC in powder form (prototype) As can be seen from the above example, a decrease in the amount of acid below 0.003 g-eq by 1 ton of Na CMC in the modifying treatment leads to a deterioration of the mechanical strength and an increase in the absorption of paper, which is the basis for setting a lower limit for the amount of acid to treat Na CMC. PRI me R 5. Another embodiment of the proposed method is illustrated by the example of a paper with a weight of 100 g / m with a fiber composition: cellulose sulfate bleached grade A-11-70%, bleached aspen sulfate pulp grade OB-1-30 % The prepared fiber suspension with a concentration of 2% was divided into 4 portions. In the first batch, 3 wt.% Of the absolutely dry Na CMC fiber, pretreated with a 7% citric acid solution, taken in an amount of 0.008 g-eq per 1 g, was introduced.

0.0015 g-eq NYOZ per 1 g of Na, taken as an 8% aqueous solution for 45 min. The process of modifying acid treatment is at a pH of about 2.5.

In the third variant, the fibrous suspension was injected with 1.5% Na CMC (in terms of absolutely dry matter based on the weight of cellulose) in the form of a dry powder (according to the protype). The process of grinding, sizing in the mass at pH-5.0 and the pouring out of thus prepared susp, pensions are carried out as in Example 1. For sizing in the mass, white, glue based on EMI is used in an amount of 2% by weight of cellulose.

After pressing and drying the castings, the wt.coji.lOO g / m have the values given in table. 3

Table 3

10.0

3830

10.5

3510

10.5

3700 Na CMC. The treatment was carried out for 30 minutes at an RC of about 2.5. In the second batch, 3 pounds of absolutely dry Na CMC fiber, pretreated with a 7% citric acid solution, taken in an amount of 0.011 g-eq per 1 g of Na CMC were introduced. The treatment was carried out for 30 minutes at a pH of about 2.5. The third portion was injected with 3% Na CMC based on the weight of absolutely dry fiber, which was pretreated for 30 min with 7% citric acid solution, taken in an amount of 0.016 g-eq per 1 g of Na CMC. In this embodiment, the pH of the medium is 2.0. In the fourth portion was added 3% Na CMC by weight of absolutely dry. fibers in the form of powder (prototype). All four weight options given above were ground with an average additive in a roll under identical conditions to a degree of grinding of 40 ± 1 ° SH. In each variant, 1.5% of white gum adhesive was added based on the weight of a completely dry fiber, and after 10 minutes a 4.5% solution of aluminum sulphate from a weight of absolutely dry WO fiber was added to a pH of 3.8, and another 10 minutes of mixing was added 50% suspension of kaolin in water at the rate of 2% kaolin by weight of absolutely dry fiber.

3% Na CMC + 0.008 g-eq. From the table it can be seen that with an increase in the amount of modifying acid from 0.008 to 0.011 g-sic per 1 g of Na CMC, an increase in the mechanical strength of the resulting paper is observed, and a further increase in the amount of acid from 0.11 g- eq to 0.016 does not lead to an increase in the mechanical strength of the paper, but leads only to unjustified acid waste. In addition, it should be borne in mind that a large amount of a strong acid may lead to the cleavage of the carboxymethyl groups of the Na CMC. Based on the results obtained, the upper limit of the amount of acid can be established for the modification of Na CMC. As follows from the above data, the experimental basis of the diazo paper obtained from the paper pulp treated according to the invention is superior to the paper obtained from the paper pulp processed according to the prototype, by an average of 10% in rip length, by more than two times in fracture resistance, for absorbability with one-sided wetting in water for 30 s - an average of 7%. Samples were cast from the paper pulp prepared in this way on a Rapid-Ketten apparatus and pressed and dried under identical conditions. Four variants of the paper obtained in the described manner were subjected to tests after conditioning at a humidity of 65% and a temperature of 20 ° C. The results of the tests, averaged over 10 castings, are given in table. 4. Table 4 The use of the proposed method for preparing paper pulp reduces the consumption of hardened additives (Na CMC), prevents Na CMC from sticking to the papermaking equipment, and reduces the consumption of rosin products due to a decrease in paper absorption. The basis for the diazo paper, made in the process of excavation at the Dobrush factory, the Hero of Labor, in addition to improving the properties already listed, after applying the photosensitive layers also showed a significant improvement in the consumer properties of diazo paper, such as increasing the copying speed and increasing resolution of diazo paper 1 Therefore, the use of the proposed method of preparing paper pulp, besides improving the properties of the base paper, makes it possible to significantly improve the quality and range of technical papers — in particular diazo paper. The economic effect of the introduction of this invention in the release of 20 thousand tons. papers; will be more than one million rubles.

11, - - 69906812

  well

Formula of ISO and 0.011 kg-eq per 1 kg of sodium carboxy; Method of preparation of paper pulp by

grinding cellulose fibers in the presence of sources of information,

carboxymethylcellulose sodium salt, taken into account in the examination

day auxiliary substances and sizing - US Patent No. 2572932, cl. 162-177,

in bulk at pH 3.8-5.0, distinguishing 1951.

so that, with the aim of increasing mechanical2. Fl M.T. M. Properties of paper, M., Potency and reduced paper absorbency, from industrial sawmilling, 1976, p. 104-110. before grinding the “carboxymethyl salt of salt” ° 3. Butai A.S., Goncharova V.L. The grinding of cellulose is subjected to treatment with the preparation and preparation of paper pulp, M., Lesokislota, in the amount of 0.003, “industry, 1976, s.- 86

methylcellulose at pH 0.6-2.5.