FI96520B - Procedure for the prevention of resin difficulties - Google Patents

Abstract

A process for preparing mechanical pulp and/or paper containing the mechanical pulp is described, wherein an acylglycerol lipase is used. The process according to the invention avoids the problems caused by the resins in the preparation of mechanical pulp and/or paper containing said pulp.

Description

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The present invention relates to a method for avoiding resin difficulties in a process for producing mechanical pulp and / or paper containing mechanical pulp.

A mechanical pulp such as groundwood (hereinafter abbreviated as GP), grinder and hot grinder are produced by a simplified mechanical treatment in which the dust or chips are ground in a grinder or grinder. The advantages of a mechanical pulp with a lower strength are higher yield, lower cost · and better opacity compared to a chemical pulp made with various chemicals such as alkaline chemicals. The constituents of wood, on the other hand, remain unchanged in the mechanical pulp.

Wood generally contains about 1-10% resin and organic solvent soluble extractants in addition to the three main components which are cellulose, hemicellulose and lignin. The quantity and quality of resin varies depending on the species of wood. However, it is known that softwood, the main raw material for mechanical pulp, contains a large amount of resin constituents such as fatty acids, rosin acids, glycerides, etc. In cooking, these resin constituents are released from the pulp, where they are free, precipitated on the fibers. . In other words, they move from a bound state to a free state. The resins suspended in reuse water (circulating water) are microparticles with a diameter of 0.2-2 μU, known as 30 ns. "Kolloidipihkana".

The paper is made as follows.

• The pulps are produced in different cooking processes, handled in a sorting process and various additives are mixed into the pulps to make paper pulp. Paper 35 is made from paper stock in a paper machine. In the series of processes 96521, the released resin or precipitated resin accumulates in pipelines, tanks, wire sections or presses and is formed by the so-called resin problems such as paper soiling or paper breaks. Resin difficulties are common in the production of paper rich in mechanical pulp. One conventional method of avoiding resin difficulties is the so-called air drying, in which the logs are stored outdoors and air dried for a relatively long time. Another method of avoiding resin difficulties is to add a surfactant to a cooking or papermaking process, as described in JP Patent Publication No. 50-22606, wherein the surfactants are, e.g., polyoxyethylene alkyl ether, which is added in varying molar amounts. alkylphenyl derivatives and chemicals containing them as the main constituent.

Although the resin constituents of wood change and decrease in the air drying process described above mainly due to the oxidizing effect of air, the process requires large areas and a long time, i.e. 3-6 months 20 or more. In practice, therefore, it is difficult to avoid resin difficulties by the air-drying method mentioned above alone.

On the other hand, the addition of a surfactant, which is said to disperse the resin particles and prevent resin precipitates, has not been found to be an essential method to avoid resin difficulties.

It is an object of the present invention to avoid resin difficulties in a process for making mechanical pulp or paper containing mechanical pulp. The object mentioned above is achieved by treating the pulp and / or circulating water with acylglycerol lipase in a process for producing mechanical pulp and / or paper containing mechanical pulp. The following description clarifies the object and features of the present invention.

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In order to provide an effective method to avoid resin difficulties, the inventors have studied in detail the following: 1) resin constituents extracted from Japanese red pine (Pinus densiflora) as a mechanical pulp, and 2) resin constituents precipitated in the process of Japanese red pine-ty-GP and / or pine GP-containing paper. As a result, the main constituents of the precipitated resin were the same as the main constituents of the original resin of the wood 10 and consist mainly of triglycerides, fatty acids, rosin acids and their metal salts. In addition, it has been shown that precipitated resin always contains a large amount of triglycerides. It has been hypothesized that triglyceride is one of the major constituents of pih problems. Since the decomposition or removal of triglycerides in some way effectively removes resin difficulties, the inventors have studied various chemical or biochemical methods.

As a result of the studies, the object of the present invention has been achieved by using acylglycerol-20 passage, whereby the triglyceride decomposes and thus no resin precipitates occur which adversely affect the quality and driving properties of the pulp or paper. This means that the object of the present invention is achieved by treating paper pulp and / or recycled water with acylglycerol lipase in a process for producing mechanical pulp and / or paper containing mechanical pulp.

The acylglycerolipase is preferably a lipase formed by at least one microorganism selected from the group consisting of Aspergillus niger, Pseudomonas fluorescens, Pseudomonas 30 fragi, Geotrichum candidum and Candida cylindracea.

The acylglycerol lipase of the present invention is an enzyme for the hydrolysis of triglycerides, i.e. one major constituent of resin. Any enzyme can be used as long as it hydrolyzes the triglycerides.

4 9 6 5 2! The enzyme-producing microorganisms of the present invention include, for example, Aspergillus niger, Pseudomonas fluorescens, Pseudomonas fragi, Geomtrichum canedum, Candida cylindricea, Mucor javanicus, Rhizopus javanicus, Rhizopus delemar, Rhizopus niveus, Rhizopus niveus. Of these fungi, others more effective are Aspergillus niger, Pseudomonas fluorescens, Pseudomonas fragi, Geotrichium candidum, and Candida cylindracea.

10 The purer the acylglycerolylase produced by the above microorganisms, the more effective it is. In addition, acylglycerol lipases are used alone or in combination. Good potency can also be obtained by using the acylglycerol lipase of the present invention in combination with other degrading enzymes such as cellulase, hemicellulase, pectinase, protease, etc.

In the process for preparing mechanical pulp and / or paper containing mechanical pulp, the acylglycerol lipase of the present invention is added to the pulp with stirring or standing. In this case, the enzyme of the present invention is added to the stock in an amount of 0.1 to 10,000 ppm (by weight) based on the weight of the mechanical pulp, and the temperature is preferably 10 to 70 ° C, more preferably 35 to 55 ° C. Below 10 ° C the enzyme works weakly and slowly. Above 70 ° C the enzyme may be inactivated. As the amount of enzyme increases, the reaction usually accelerates and 10,000 ppm of enzyme by weight of the mechanical pulp is satisfactory when calculated from the amount of the triglyceride forming the substrate. The addition of more than 10,000 ppm of enzyme is economically disadvantageous. A suitable pH is 3-11 and this! outside the range, the activity of the enzyme decreases appreciably ti.

The cooking of the papermaking process uses large amounts of water, much of which is recycled and used; 9652ί 5 again. Because the reused water (circulating water) contains resin ingredients / the addition of acylglycerol lipase to the stormwater prevents resin difficulties.

In this case, excellent results are obtained by adding the above-mentioned acylglycerol lipase directly to the circulating water or by adding the so-called immobilized acylglycerol lipase or so-called an immobilized microorganism capable of producing acylglycerol lipase outside the cells, wherein the immobilization of the enzyme or microorganism is carried out by conventional methods, e.g. by binding, crosslinking, retaining or the like to a carrier.

Since the method of the present invention causes a highly selective reaction, i.e., the enzyme-1 reaction with respect to the triglyceride, and since this reaction is mild, the enzyme-treated stock is not denatured, and thus the method of the present invention does not interfere with normal operation.

Resin difficulties arise in a complex system consisting of pulp fibers, resins, metal ions, fillers, etc. Although the causes of resin difficulties are not fully known, it is assumed that resin difficulties are due to many factors such as resin concentration, pulp concentration, pH concentration. , temperature, concentration of metal ions, quality of metal ions and similar factors. In general, adsorption to a solid surface is due to van der Waals forces that attach the substance adhered to the solid surface.

The substance and the solid interact with each other and hydrophobic bonding, dipole moment interaction, etc. are important for the effects. A hydrophobic or non-polar surface readily attracts a hydrophobic or non-polar molecule or a hydrophobic molecular moiety and a polar surface readily attracts a hydrophilic or polar molecular moiety. Considering the mechanism of resin precipitation in the pulp or papermaking process, triglycerides thus play the next part. Under the influence of the van der Waals forces, the triglycerides, i.e. the non-polar component of the colloidal resin, adhere to a hydrophobic or non-polar surface such as metal surfaces of tanks, pipelines, etc., the central roll of the papermaking press section and the like. The adhered moiety acts as a core and the hydrophobic or non-polar molecules or hydrophobic moieties of the resin components gradually adher to and form resin precipitates.

The mechanism by which resin precipitates are avoided according to the present invention is as follows. Acyl-glycerol lipase acts on a non-polar triglyceride present in the surface resin or colloidal resin of the pulp (such as circulating water resin) and strongly adheres to hydrophobic and non-polar surfaces, whereby the triglyceride is hydrolyzed to a water-soluble glycerol and a polar fatty acid. In this way, resin precipitation on the surfaces of metal pipelines, troughs, rollers 20, etc. is avoided. Because resin precipitates are avoided at an early stage, no increase in resin precipitates occurs, which eliminates resin difficulties.

The method of the present invention has the advantage of avoiding resin difficulties such as resin spots and holes in the paper web, etc., which result from resin precipitation in the production of mechanical pulp or paper containing mechanical pulp. In addition, the method of the present invention does not adversely affect the quality or practical operation of the paper and is simple and applicable to a conventional pulping and papermaking process without the need to install additional equipment.

The following examples facilitate the understanding of the present invention. These examples are intended to illustrate the present invention without limiting the scope of the present invention. In all il ItH I il il: ΐ 7 9652! in the examples, non-enzyme-treated samples are referred to as “controls”.

Example 1

Fresh Japanese red pine chips were extracted with methanol in a Soxhlet extractor. 10 g of the obtained extract was dissolved in a mixture of 100 ml of isopropanol, 60 ml of acetone and 5 ml of water to give a resin solution.

10 ml of the resin solution was added to a 1 liter beaker containing water and dispersed vigorously to a resin dispersion. In this way, 4.7% of the resin, calculated from the oven-dried chips, was obtained. The resin contained 37.8% triglycerides.

The pH of the resin dispersion was then adjusted to 7 by the addition of hydrochloric acid and / or sodium hydroxide.

Acylglycerol lipase was added to the dispersion at varying concentrations and temperatures as shown in Table 1 and treated with slow stirring for 4 hours to give a treated solution. A pin according to the routine control method RC-324 was placed 2.5 cm above the water surface at 20 cm above the cylinder made of polyethylene sheet, diameter 22 cm and length 7 cm. The adjusted solution was stirred for 30 minutes with a Vibromixer (Linitator, manufactured by U.S. Heidon Co.).

The cylindrical polyethylene sheet was removed and dried. The weight and percentage of resin precipitate relative to the untreated pulp are shown in Table 1.

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Table 1 ! ___Enzyme_ _; Temperature _

^ j Species Concentration 20 * C 40 * C 60 * C

Control - 115 mg 102 mg 117 mg __ (100%) (100%) (100%) 50 ppm - 93 mg 10 (80.0%) 500 ppm 58 mg 35 mg 90 mg

Li. OF1)! (50.4%) (30.4%) (78.3%) 1000 ppm - 28 mg 15 _____ (24.3%) __ 500 ppm 66 mg 54 mg 96 mg

Li. > _ _ (57.4%) (47.0%) (83.5%) 9n 500 ppm 67 mg 60 mg 83 mg | Li. P3) (58.3%) (52.2%) (72.7%)

Note. 1 Li. Of, trade name = Lipase OF (manufactured by Meito-25 Sangyo Co.), produced by the microorganism Candida cylindracea.

• Note. 2 Li. A, trade name = Lipase A (manufactured by Amano

Seiyaku Co.) produced by the microorganism Aspergillus niger.

30 Note. 3 Li. P, trade name = Lipase P (manufactured by Amano

Seiyaku Co.) produced by the microorganism Pseudomonas fluorescens.

Note. 4 Concentration = concentration of enzyme addition calculated on the resin.

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Example 2

The pH of the resin dispersion was adjusted to 7 with hydrochloric acid and / or sodium hydroxide. Acylglycerol lipase was added to the dispersion in an amount of 500 ppm by weight of resin and stirred at 40 ° C. After a certain time, the amount of precipitated resin was obtained in the same manner as in Example 1, and the results are shown in Table 2.

Table 2 10 _ ____

The enzyme ___ T.ämpötiLa--

Species concentration__2 hours 4 hours 8 hours

Control '- 105 mg 101 107 15 ___ (100 ») (100%) (100%) 500 ppm 67 mg 31 mg 31 mg

Li. OF

(63.8%) (30.7%) (24.4%) 500 ppm 85 mg 70 mg 59 mg

Li. GC-55> 20 (81.0%) (69.3%) (55.1%)

Note. 5 Li. GC - 5, trade name = Lipase GC - 5 (manufacturer

Amano Seiyaku Co.3 produced by the microorganism Geotrichum candidum.

Example 3, A 1 liter dispersion containing 10 g GP was prepared from Japanese red pine, CSF (Canadian Standard Freeness) 63 ml.

Acylglycerol lipase was added to the dispersion at varying concentrations and treated at varying pH values in the same manner as in Example 1.

The amount of resin precipitated on the surface of the cylindrical polyethylene sheet was measured as described in Example 1, and the results are shown in Table 3.

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Table 3, Enzyme ___________ 5 Species Concentration ^ 3 5 _7__9_.,. 115 mg 112 mg 102 mg 121 mg

Control ----- (100%) (100 L) (100%) (100%) Lo ppm - - 90 mg 10 (88.2%) _ 50 ppm 80 mg 58 mg 28 mg 62 mg

Li. OF

(67.8%) (51.8%) (27.5%) (51.2%) 250 ppm - - 21 mg 15 (20.6%) 10 ppm - - 96 mg '____ (79.3%) %) 50 ppm 95 mg 65 mg 42 mg 27 mg 20 Li. b6) (80.5%) (58.3%) (41.2%) (22.3%) 250 ppm - - - 24 mg _____ (19.8%) 25 50 ppm 84 mg 66 mg 49 mg 88 mg

Li. Λ [71.2%) (58.9%) (48.0%) (72.7%) (40 ° C, treatment time 4 hours)

Note. 6 Li, B, trade name = Lipase B (manufactured by Sapporo 30 Breweries Limited), producing microorganism Pseu domonas fragi 22-39 B.

Note. 7 concentration = concentration of enzyme addition based on mass.

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Example 4 The same sample as in Example 3 was used. The enzyme of the present invention was added to the sample in an amount of 50 ppm by weight of resin 5 and treated in the same manner as in Example 1 with varying temperature and time. The amount of resin precipitated was measured and the results are shown in Table 4.

Table 4 10 _______ Enzyme Temperature

Type pH Treatment- 20 * C 40 * C 60 * C

time 15 Control - 115 mg 102 mg 117 mg (100%) (100%) (100%) 2 hours - 44 mg ___ (53.9%) ___ 7 20 Li. OF 4 hours 64 mg 29 mg 100 mg (S5.7%) (28.4%) (85.5%) 8 hours - 27 mg (26.5%) ___ • 25 Control - 128 mg 121 mg 134 mg ( 100%) (100%) (100 h) for 2 hours - - 43 mg (32.3%) 30 9 -— ~

Li. B 4 hours 97 mg 27 mg 26 mg (75.8%) (22.3%). (19.4%) 8 hours - - 25 mg (18.7%) 35 ____ L - 9652 (

12 A

Example 5

A 1% pulp stock was prepared with 20% newsprint pulp (CSF 105 ml), 25% GP (CSF 63 ml), 25% hot milled (CSF 107 ml) 5 and 30% kraft pulp. 1 liter of this pulp stock was used as a sample. The enzyme of the present invention was added to the roll in an amount of 50 ppm by weight of the pulp, treated for 4 hours at 40 ° C and mixed with a Vibromixer with a cylindrical polyethylene sheet. The amount of resin precipitated was measured and the results are shown in Table 5.

Table 5

Amount of precipitated resin 15 Control 65 mg (100%)

Lipase OF 18 mg (27.7%)

Example 6 3 liters of circulating water obtained by filtering a GP made of Japanese red pine in the sorting step was used as a sample. The enzyme of the present invention was added to the sample in an amount of 0.5 ppm by weight of circulating water, treated for 2 hours at 40 ° C and mixed for 120 minutes with a Vibromixer.

25 The amount of resin precipitated on a cylindrical polyethylene sheet was measured and the results are shown in Table 6.

Table 6

Amount of precipitated resin 30 Control 37 mg (100%)

Li. OF 7 mg (18.9%) of Ittt iin hltf i e i 9652s 13

Example 7

Newsprint was produced, basis weight 2 about 46 g / m 2, in a Bel-Baie web former multi-drying cylinder paper machine, width 5080 mm and speed 830 m / min, 5 where the paper stock contained 30% GP, 45% newsprint pulp (deinked), 10% softwood kraftmas and 15% hot rub.

In this case, GP was made from red pine and adjusted to freeness by 60-70 ml CSF post-milling, stored for some time as pulp, optionally mixed with other pulps and additives, re-stored and fed to the papermaking process. The journey from the post-grinder through the trays and tanks to the paper machine took 90 minutes. The enzyme of the present invention was added to a GP stock having a consistency of 3.8% before post-milling so that the concentration of lipase OF became 3 ppm. The enzyme was added continuously to the GP stock over two weeks.

The amounts of resin deposited on the wire and press sections and the removal intervals of resin precipitated on the center roll were determined. The capacity of the paper machine was practically about 270 tons per day. Removal of resin deposited on the center roller helps to prevent resin precipitation that interferes with good driving. As the number of resin deposits increases, the removal intervals of the resin deposited on the center roll are shortened. The results obtained were compared with those obtained with the "control" and the results are shown in Table 7.

Table 7

Check_Li. OF

3 ° Amount of precipitated resin Max. 895 89 (g / day) Min. 73 0

Average 207 43

Precipitation resin max. 120 240 removal interval (min. Min. 30 120 35 Average 80 170 14 9 6 5 2 ί

Example 8

According to Example 7, a lightweight printing paper with a basis weight of 34 g / m 2 was prepared, the pulp containing 20% GP, 50% newspaper collection paper pulp 5 (deinked), 15% softwood kraft pulp and 15% hot milling. Lipase OF was added to the GP stock in an amount of 3 ppm. The capacity of the paper machine was practically about 200 tons per day. In comparison to the "control" results, the amount of resin deposited on the wire and press sections and the resin-10 holes in the paper due to the resin precipitation in the intermediate calender were determined. The results are shown in Table 8.

Table 8

Check Li. OF

15 Amount of precipitated resin Max. 590 98 (g / day) Min. 132 15

Average 221 47

Number of resin holes * Max. 65 14 (per day) Min. 13 0 20 Average 38 6 * Expressed as the number of small strips of paper that peeled off in the intermediate calender.

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Claims (6)

A method for avoiding resin troubles in a process for producing mechanical pulp and / or paper containing mechanical pulp, characterized in that paper stock and / or return water is treated by the addition of acylglycerol lipase. 2. A method according to claim 1, characterized in that said acylglycerol lipase is a lipase formed by a microorganism selected from Aspergillus niger, Pseudomonas fluorescens. Pseudomonas fragi, Geotrichum candidum and Candida cylindracea. Method according to claim 1, characterized in that said acylglycerol lipase is added in the paper stock 0.1 - 10,000 ppm, based on the weight of the mechanical pulp. Method according to claim 1, characterized in that the temperature of said paper stock and / or of the return water is between 10 - 70 ° C. 20 5. A process according to claim 1, characterized in that the temperature of said paper stock and / or of the return water is between 35-55 ° C. 6. A process according to claim 1, characterized in that the pH of said paper stock 25 and / or of the return water is between 3 - 11.