JP2579700B2 - Hardwood pulp strength improvement method - Google Patents

Description

The present invention relates to improving the specific tear strength of hardwood pulp by treating the hardwood pulp with an enzyme derived from mushrooms in the papermaking industry.

[Prior Art] Since the strength of pulp is directly reflected on the properties of paper as a product, conventionally, pulp strength has been improved by physical means such as beating and chemical methods by adding chemicals. Was. Recently, a biochemical method using a microorganism or an enzyme has been proposed as a new method. For example, JP-A-63-135597 discloses that surface strength, smoothness and tensile strength are improved by enzymatic treatment of pulp. Japanese Patent Publication No. 2-20756 discloses that the beating speed is increased by adding an enzyme that degrades pulp.

[Problems to be Solved by the Invention] However, improvements by physical means increase equipment costs and energy costs, while improvements by chemical methods often lead to contamination of processes and troubles associated therewith. . Japanese Patent Application Laid-Open No. 63-135597 mainly deals with measures against vessel pickling, and Japanese Patent Publication No. 2-20756 only aims at accelerating beating. Therefore, the enzyme used in these patents does not improve the specific tear strength.

Specific tear strength is one of the important strength factors as well as various strengths indicating the properties of pulp, such as tensile strength, burst strength, tear length, bending strength, etc., and is measured by measuring specific tear strength. The force required to pull out the fibers from the paper layer structure of the sheet and the force required to cut the fibers are evaluated. Generally, the longer the fiber length, the higher the specific tear strength, and the maximum specific tear strength when the bonding area between the fibers is optimal.

Therefore, the present invention proposes a method for improving the specific tear strength of hardwood pulp by enzymatic treatment.

[Means for Solving the Problems] As a result of extensive studies for the purpose of improving the specific tear strength of hardwood pulp by enzymes, the present inventors have found that
Hiirotake (Pycnoporus coccineus, formerly Trametes sang)
uinea) have been found to work extremely effectively.

The mushroom used in the present invention is Pycnopor
us coccineus (former name: Tremetes sanguinea), which produces enzymes such as cellulase (CMase, C1 cellulase, cellobiase, fibrin permeation), β1,3 glucanase, and protease (Journal of Fermentation Engineering, 42
Vol. 7, No. 7, July, pp. 405-414, 1964). Specifically, for example, Pycnoporus coccineus (former name Tremetes s
angunea) IFO7045. The cultivation of the present bacterium to accumulate the oyster mushroom enzyme can be achieved by usual stationary culture, shaking culture, aeration and agitation culture, or solid culture, but aeration and agitation culture is particularly desirable. The medium to be used may be of a normal composition capable of growing the microorganism used, and the carbon source may be a carbohydrate (eg, glucose, maltose, lactose, sucrose, etc.),
Any suitable fats and oils (soy oil, corn oil, etc.), fatty acids (stearic acid, etc.), organic acids (succinic acid, lactic acid, acetic acid, etc.) or alcohols (glycerin, ethylene glycol, ethanol, etc.) can be appropriately used. Selected and used alone or mixed. Nitrogen sources include, for example, organic nitrogen sources such as peptone, soy flour, cottonseed flour, corn steep liquor, yeast extract, malt extract, meat extract, whey, casein, as well as ammonium sulfate, ammonium nitrate, salt ammonium and phosphorus ammonium. Inorganic nitrogen sources such as are appropriately mixed or used alone as needed. In addition to the carbon source and the nitrogen source, the medium may contain essential factors and promoting factors such as minerals, amino acids, and vitamins necessary for growth and formation of enzymes. In addition, an inducer such as cellulose may be added to induce cellulase. For the purpose of controlling pH and foam during culturing, it is effective to appropriately compensate for calcium salts such as aqueous sodium hydroxide solution, sodium carbonate, and calcium carbonate, and to add an antifoaming agent.

The temperature for cultivation may be appropriately selected depending on the microorganism used, and is usually 15 ° C to 60 ° C, preferably 25 ° C to 50 ° C. The culturing time is continued for a time sufficient for the production of the microorganisms and enzymes to be used, but usually requires 1 to 10 days.

By culturing in this way, the mushroom enzyme
Usually, they are secreted by microbial cells and dissolved and accumulated in the medium.
Accordingly, a crude enzyme solution is obtained by removing bacterial cells and insolubles using a filter press, an Oliver filter, centrifugal separation, sedimentation separation, coagulation separation, porosity, a polymer membrane, a ceramic membrane, or the like. This crude enzyme solution can be immediately used for practical use, or it can be used after being concentrated by a usual concentration method such as concentration under reduced pressure. It is also possible to obtain a crude enzyme powder by a usual drying method such as freeze drying and spray drying and use it. In addition, these crude enzymes can be treated with ordinary enzymes such as protamine treatment, salting out, organic solvent treatment, surfactant treatment, isoelectric point precipitation, electrophoresis, ion exchange chromatography, hydrophobic chromatography, gel filtration, and affinity chromatography. The purified enzyme obtained using the purification means can be applied to the enzyme treatment described in the present invention. The resulting mushroom enzyme can be found in the Journal of Fermentation Engineering (No.
42, No. 7, pp. 405-409, 1964). That is, it has a cellulase activity having a maximum activity at pH 3.5 to 4.5 (filter paper disintegration method), hydrocellulose degrading activity, CMCase having a maximum activity at pH 4.0 to 5.0, β-1,3 glucanase, and the like.

The concentration of the hardwood pulp used for the reaction is 1 to 5%, but a lower concentration is particularly desirable. The amount of the enzyme to be added is 0.05 to 5% by weight, preferably 0.5 to 2%, based on pulp (absolutely dried).
% By weight. The pH of the reaction may be any value as long as it is in the range of 3 to 9, but 5 to 7 is particularly suitable. Temperature is 20-70
C., especially 30-60.degree. The reaction time may be appropriately set, but about 3 hours is appropriate. The reaction may be either standing or stirring, but a gently stirring reaction that does not cause sedimentation of the pulp slurry is desirable. Beating can be carried out arbitrarily before and after the addition of the enzyme. However, when it is carried out after the addition of the enzyme, a better effect can be obtained. Thereafter, the sheet is formed according to a conventional method to prepare a sheet.

[Examples] Hereinafter, the present invention will be described in detail with reference to Examples. Note that the present invention is not limited by this.

(Example 1) For the preparation of Hilotake mushroom enzyme, see Journal of Fermentation Engineering, No. 42
Vol. 7, No. 7, page 405 (1964). That is, a 500-m medium consisting of 5% soluble starch, 2% corn steep liquor, 3% defatted soy flour, 0.2% potassium monophosphate and 0.1% magnesium sulfate.
l to 20% caustic soda aqueous solution to adjust the pH to 6.0.
Was adjusted. This is poured into 2 Masuguchi flasks, and 12
Steam sterilization was performed at 0 ° C. for 20 minutes. Pycnoporus on this
After inoculating a slant culture of coccineus (former name: Trametes sanguinea) IFO7045, the cells were cultured at 28 ° C. for 48 hours on a reciprocating shaking incubator (80 spm). Next, 40 tap water was put into a 200-solution fermentation tank, and 3.5 kg of soluble starch, 1.4 kg of corn steep liquor, 2.1 kg of defatted soybean powder, and 0.14 potassium monophosphate were added.
After adding 0.07 kg of magnesium sulfate and mixing well, 20% aqueous sodium hydroxide solution was added dropwise to adjust the pH to 6.0. Next, the mixture was steam-sterilized at 120 ° C. for 20 minutes while stirring at 100 rpm. The volume of the medium was adjusted to 70 by adding sterile water, and then cooled to 28 ° C. Two Sakaguchi flask cultures (500 ml) were inoculated into this medium and aerated at 1 VVM (aerated volume per minute per unit volume), internal pressure 1.0 kg / cm ² gauge, and stirred at 160 rpm under the conditions of 28 rpm.
The cells were cultured at 140 ° C. for 140 hours.

The pH of the culture solution thus obtained was adjusted to 6.0 by dropping a 20% aqueous solution of caustic soda, and then 5 kg of Radiolite 700 (filter aid) was added and stirred. This was filtered with a filter press (manufactured by Noritsu Tekko) under conditions of a filtration area of 30 m ² , a pressure of 150 kg / cm ² and room temperature. Filtrate 1 was collected and salted out by adding 600 g of ammonium sulfate thereto. The precipitate was collected by a centrifuge at 5000 × g for 20 minutes, 5 minutes.
Collected under the condition of ° C. The precipitate was dissolved in 300 ml of water, sealed in a dialysis membrane, and dialyzed against 30 distilled water at 5 ° C. for 24 hours. The dialysate is freeze-dried (FD-1 type,
The product was freeze-dried under the conditions of 30 Pa by Tokyo Rika Kikai Co., Ltd. to obtain 20 g of crude enzyme powder of Hirotake mushroom.

Separately, foreign-produced LBKP (hardwood bleached and dried kraft pulp) was suspended in water, defibrated with a defibrillator to a concentration of 1%. To this pulp slurry, 1% by weight of the above-mentioned crude enzyme powder derived from Hiirotake was added per pulp (absolutely dried), and the pH was adjusted to pH.
Reaction was carried out with gentle stirring at 6.5 and 45 ° C for 3 hours. After the reaction, beat with a PFI mill to make the pulp freeness 450 ml,
A hand-made sheet was prepared using a test machine in a conventional manner.

The tear strength of the obtained sheet was measured according to JIS P-8116, and the specific tear strength was calculated from the basis weight of the sheet.

(Comparative Example 1) In Example 1, the specific tear strength of a sheet similarly treated under the condition where no enzyme was added was measured.

(Comparative Example 2) A 5% concentration slurry of LBKP was adjusted to pH 5, and 0.5 of cellulase (trade name: SP227, manufactured by Novo Denmark) was added.
The temperature was kept at 50 ° C. for 4 hours. After setting the freeness to 450 ml, a hand-made sheet was prepared, and the specific tear strength was measured.

(Comparative Example 3) A handmade sheet was prepared in the same manner as in Comparative Example 2, except that a 1% concentration slurry of LBKP was used and the amount of cellulase added was 1% by weight per pulp (absolutely dried). And the specific tear strength were measured.

(Comparative Example 4) In Comparative Example 2, an amylase (trade name: Termamyl,
A hand-made sheet was prepared in the same manner except that 4.5% by weight per pulp (absolutely dry) of Novo Denmark was added, and the specific tear strength was measured.

(Example 2) Domestic LBKP (wet pulp) was made into a 1% concentration slurry, and the enzyme powder used in Example 1 was added at 1% by weight per pulp (absolutely dried), and reacted in the same manner as in Example 1. Was. After completion of the reaction, the freeness was set to 400 ml to make a hand-made sheet,
The specific tear strength was measured.

(Comparative Example 5) In Example 2, the specific tear strength of a sheet similarly treated under the condition where no enzyme was added was measured.

Table 1 summarizes the measurement results obtained in the above Examples and Comparative Examples.

[Effects of the Invention] According to the present invention, broad-leaved tree pulp (Pycnop)
By applying an enzyme derived from orus coccineus (former name: Trametes sanguinea), the specific tear strength, which is an important strength factor of pulp, can be greatly improved. Furthermore, the method of the present invention does not require any special equipment, does not cause any inconvenience in the process, and has excellent operability. At the same time, it is not subject to the limitations of the pulping method and can be applied to any pulping method.

Continued on the front page (72) Inventor Kihachiro Oshima 5-2-1-1, Oji, Kita-ku, Tokyo Inside Jujo Paper Co., Ltd. (72) Inventor Kunio Hata 5-2-1-1, Oji, Kita-ku, Tokyo Jujo-made In the Central Research Laboratory of Paper Co., Ltd. (72) Inventor Setsuki Suzuki 2-12-10 Nihonbashi, Chuo-ku, Tokyo Takeda Pharmaceutical Co., Ltd. Production Technology Research Laboratory (56) References JP-A-63-135597 (JP, A JP-A-1-92490 (JP, A) JP-A-2-160997 (JP, A) JP-A-58-188062 (JP, A) JP-A-2-80686 (JP, A) 20756 (JP, B2)

Claims (1)

(57) [Claims] (1) A broad-leaved pulp is mixed with Pycnoporus (Pycnoporus).
A method for improving the strength of hardwood pulp, characterized by improving the specific tear strength of pulp by the action of an enzyme produced by coccineus (former name: Trametes sanguinea).