TWI420010B - Method for preparing non-wood fiber pulp - Google Patents

Description

Method of making non-wood fiber slurry

This invention relates to a process for making a non-wood fiber slurry; in particular, the present invention relates to a process for the preparation of a non-wood fiber slurry by subjecting a non-wood fiber material to an enzyme treatment with a xylanase.

In the paper industry, wood fiber materials are mainly used to provide paper pulp, while lignocellulose materials are generally classified into wood and non-wood according to their plant characteristics. Wood fiber materials such as pine, poplar, eucalyptus Such as perennial plants, non-wood fiber materials such as rice straw, wheat straw, bagasse, cotton straw, linen and other common annual crops. Among them, non-wood fiber materials generally use wood fiber materials as pulping materials because of their generally short fiber length and high impurity content. However, wood fiber materials are usually taken from perennial plants that are valuable and slow to grow, which are costly and difficult to plant; in contrast, non-wood fiber materials are mostly non-economical parts of agricultural plants (such as rice straw and wheat straw). , bagasse, cotton stalks, etc.), not only easy to obtain, short growth time, but also do not need to be planted for the purpose of papermaking, and will not destroy the natural ecology.

In addition, the papermaking process mainly comprises two steps of making the lignocellulosic material into a paper pulp and then making the paper pulp into paper by papermaking. At present, the preparation method of the paper pulp mainly includes a chemical pulping method, a semi-chemical pulping method, and a mechanical pulping method. Among them, compared with the chemical or semi-chemical pulping method, the mechanical pulping method has gradually gained attention due to its advantages of low construction cost, high yield of pulping, and less environmental pollution; on the other hand, mechanical pulping is mainly The mechanical fiber is used to tear the cellulose fiber and further pulp, so the high energy consumption in the refining stage is its main disadvantage. Therefore, there has been proposed an improved mechanical pulping method combining mild chemical treatment or enzyme treatment. For example, U.S. Patent Application Publication No. 20050241785 discloses a mechanical pulping method for softwood, which teaches the addition of pectin decomposing enzyme prior to refining to pretreat the raw material to reduce the refining power loss; In the application publication No. 101130936, a method for reducing the energy consumption of the mechanical pulp refining section is disclosed, which is followed by a hydrolyzing enzyme to perform enzymatic treatment on the coarsely ground slurry by a hydrolyzing enzyme. Reduce the refining power of the fine grinding section.

As can be seen from the above, the paper industry currently focuses on the use of mechanical pulping and the use of wood fiber materials as pulping materials to provide paper pulp. The invention provides a mechanical pulping method using non-wood fiber materials, in addition to avoiding the use of a large amount of chemical agents to pollute the ecological environment, and converting non-wood fiber materials which are not economically valuable into valuable renewable resources to reduce Consumption of natural resources and reduced papermaking costs.

It is an object of the present invention to provide a method of making a non-wood fiber slurry comprising: providing a non-wood fiber material; subjecting the non-wood fiber material to a hydrolysis treatment; before or after the hydrolysis treatment, using a xylanase The non-wood fiber material is subjected to an enzyme treatment; and after the hydrolysis treatment and the enzyme treatment, the non-wood fiber material is subjected to a refining treatment to obtain the non-wood fiber slurry.

The above described objects, technical features and advantages of the present invention will become more apparent from the following detailed description.

The invention will be described in detail below with reference to the specific embodiments of the present invention. The invention may be practiced in various different forms without departing from the spirit and scope of the invention. The person stated.

The invention provides a method for manufacturing a non-wood fiber slurry, which uses a non-wood fiber material (such as rice straw, straw, etc.) which is not economical value to replace the wood fiber material as a papermaking material, and performs a process before the refining treatment. Hydrolyzing, and further utilizing xylanase to destroy the xylan structure in the non-wood fiber material before or after the hydrolysis step (the fibers in the cover fiber material are usually coated or interlaced with xylan), Improve fiber dissociation efficiency, thereby reducing the consumption of subsequent refining power and increasing fiber yield and paper properties.

Specifically, the method for producing a non-wood fiber slurry of the present invention comprises: providing a non-wood fiber material; subjecting the non-wood fiber material to a hydrolysis treatment; before or after the hydrolysis treatment, using a xylanase for the non- The wood fiber material is subjected to an enzyme treatment; and after the hydrolysis treatment and the enzyme treatment, the non-wood fiber material is subjected to a refining treatment to obtain the non-wood fiber slurry.

Non-wood fiber materials useful in the methods of the present invention, such as those from economic crops that are not of economic value, may be selected from the group consisting of rice straw, straw, bagasse, cotton stalk, flax, and combinations thereof. In the method of the present invention, before the hydrolysis treatment or the enzyme treatment, the non-wood fiber material is preferably subjected to a pretreatment such as a slurry and a flat sieve treatment to initially remove impurities and retain the desired crude fiber material. Taking the rice straw as a non-wood fiber material as an example, the rice straw can be first cut into a size of about 2 cm to about 15 cm, preferably about 3 cm to about 6 cm, and then placed in a pulper. Then, adding water to carry out the slurry treatment for about 10 minutes to about 20 minutes; then, the obtained mixture is subjected to a flat sieve treatment. Generally, the flat sieve treatment can be passed through a flat sieve machine including a double-layer sieve. The upper sieve generally has a larger mesh (for example, a sieve having a hole size of about 0.4 mm to about 0.6 mm), and the lower sieve has a smaller mesh (for example, about 250 mesh to about 350). Mesh screen). By passing the obtained mixture through the double-layer sieve, the desired straw fiber material can be obtained between the upper sieve plate and the lower sieve mesh, and the non-wood fiber material is preliminarily processed. Of course, the method of the present invention can also be carried out by any conventional method, and the preliminary removal of the impurities is carried out depending on the type of the non-wood fiber material to be taken, and is not limited to the above.

The non-wood fiber material after preliminary removal of impurities is subsequently subjected to hydrolysis treatment and enzyme treatment. It has been found that the desired hydrolysis and enzymatic action can be provided regardless of whether the enzyme treatment is carried out before or after the hydrolysis treatment, which can be seen from the following examples. Therefore, according to the method of the present invention, the order of hydrolysis treatment and enzyme treatment is not particularly limited, and may be adjusted according to actual process requirements.

Without being bound by theory, the salt hydrolysis treatment can reduce the content of impurities (such as semi-fibers) in non-wood fiber materials, thereby increasing the degree of fiber dissociation. Commonly used hydrolysis treatment methods include, for example, an acid hydrolysis method, a water hydrolysis method, a vapor hydrolysis method, and the like. The acid hydrolysis method uses a mineral acid or an organic acid as a hydrolysis medium to treat the material, and sulfuric acid is used as a hydrolyzing agent. Generally, the fiber material is placed at a concentration of about 0.3% by weight to about 0.5% by weight, and the temperature is about 100 ° C. Hydrolysis is carried out in an aqueous solution of sulfuric acid at about 125 °C. The water hydrolysis method and the steam hydrolysis method are methods for prehydrolyzing the fiber material by water alone, usually by placing the fiber material in a steam environment at a temperature of about 140 ° C to about 180 ° C for about 10 minutes to about 180 minutes. Hydrolysis is carried out. In some embodiments of the present invention, a high temperature saturated vapor of about 165 ° C to about 175 ° C is introduced into a steam treatment tank for hydrolysis treatment for a period of from about 55 minutes to about 65 minutes. In addition to the above hydrolysis methods, those skilled in the art, based on the teachings of the present specification, may also employ other conventional hydrolysis methods to carry out the hydrolysis treatment.

In the method of the present invention, the temperature of the enzyme treatment depends on the optimum temperature of the enzyme itself, and the amount of enzyme added and the treatment time are adjusted according to actual process conditions, and should not be limited to a specific range. In general, considering the optimum temperature of the xylanase, the enzyme treatment step is carried out at a temperature of about 35 ° C to about 95 ° C, the treatment time is about 5 minutes to about 120 minutes, and the enzyme concentration is about 0.1 activity unit / gram. Up to about 600 units of activity per gram (the method of measuring the unit of activity of the xylanase will be described below). In some embodiments of the present invention, the xylanase aqueous solution is treated at a concentration of about 20, 40, 60, 80, 100 and 200 active units/gram at a temperature of from about 45 ° C to about 55 ° C. Non-wood fiber, which lasts from about 55 minutes to about 65 minutes. In addition, additional enzyme treatment may be performed with an additional enzyme such as cellulase, hemicellulase, cell wall enzyme, esterase, etc. before, during or after treatment with the xylanase enzyme.

Xylanase is the main enzyme that decomposes hemicellulose in sugar hydrolyzing enzymes and is used in a wide range of applications such as food, animal feed, textile or paper. In the method of the present invention, xylanase is used to destroy the xylan structure in the non-wood fiber material to improve the fiber dissociation efficiency. The type of xylanase which can be used in the method of the present invention is not particularly limited, and for example, may be selected from the group consisting of Trichoderma, Actinomyces, Aspergillus, Brachypodium, Bacillus, and Micromonas Genus, Chaetomium, Mycelium, Clostridium, Filamentous, Humicola, Neocallimastix , Nocardia, Ruminococcus , Schizophyllum, Streptomyces, Thermomonospora, thermophilic fungi, and combinations thereof. Among them, compared with the general xylanase, anaerobic fungi evolved into a highly active rumen (such as the gastrointestinal tract of ruminants and monogastric herbivores). (See, for example, Anthony et al . 1994. Anaerobic fungi in herbivorous animals. Mycol. Res. 98: 129-152, the disclosure of which is incorporated herein by reference) . Therefore, in the method of the present invention, it is preferred to use an anaerobic fungi (also known as rumen fungi) xylanase for enzyme treatment, such as the xylanase of Neocallimastix . Also used in some embodiments of the invention is the xylanase of Neocallimastix frontalis . Furthermore, according to the method of the present invention, the source of the xylanase is not particularly limited, and may be obtained by natural xylanase isolation, or obtained by artificial synthesis methods (for example, genetic engineering or peptide synthesizer), or may be Further modifications (see, for example, Taiwan Patent Application Publication No. 200720435, the disclosure of which is hereby incorporated by reference) for the benefit of the disclosure of the disclosure of the disclosure.

According to the method of the present invention, after the hydrolysis treatment and the enzyme treatment, the non-wood fiber material is subjected to a refining treatment to complete the preparation of the non-wood fiber slurry. The refining treatment essentially performs a mechanical refining treatment on the non-wood fiber material from which the impurities are removed and the xylan structure is destroyed by the xylanase to defibrate and convert the non-wood fiber material into a coarse pulp. In addition to the manner disclosed in the examples below, the mechanical refining treatment can also be achieved by any conventional mechanical refining device or method, such as wood chip grinding mechanical pulping (RMP), thermomechanical pulping (TMP), etc. (This can be referred to the Handbook for Pulp & Paper Technologies , Smook, (1992), the disclosure of which is hereby incorporated by reference in its entirety in its entirety in the in the in the The refining process is repeated several times, and after each refining process, it is preferred to filter the moisture and impurities by the screen, and then the next refining process is started. In some embodiments of the present invention, the system performs two to four The secondary refining process preferably performs three refining procedures and each time the refining process is completed, the slurry is first filtered by a sieve of about 325 mesh, and the next refining process is started.

The non-wood fiber slurry obtained by the method of the invention can be removed for moisture as needed for storage and transportation, such as transportation to a downstream paper mill for papermaking.

The method of the invention can convert non-wood fiber materials, such as rice straw, wheat straw, bagasse, cotton straw, etc., which are not economically valuable, into valuable renewable resources, which can be reduced as raw materials for mechanical pulping through the arrangement of the process. The consumption of natural resources and the reduction of papermaking costs, the way of mechanical pulping can also avoid the use of a large number of chemical agents to pollute the ecological environment.

The invention will be further illustrated by the following specific embodiments in which the measuring devices and methods are as follows:

(A) Method for measuring Canadian Standard Freeness (CSF):

Measurement method: measured by the ISO 5267-2 standard test method, in which the sample to be tested is taken to a weight of 3 g (absolute dry weight), and after adding water to 1000 ml, the CSF of the slurry is measured by a Canadian standard freeness measuring device. value.

(B) Method for measuring enzyme activity:

Measurement method: Take 90 μl of 3% by weight of xylan (Spelt wheat xylan, dissolved in a pH of 8.0 at 25 mM concentration of tris (hydroxymethyl) aminomethane Solution) As an enzyme reaction substrate, the enzyme reaction substrate was uniformly mixed with 10 μl of a specific concentration of the xylanase formulation, and the mixture was reacted at 60 ° C for 5 minutes. Subsequently, the reaction was terminated by the addition of 125 μl of dinitrosalicylic acid reagent, and the temperature was raised to 98 ° C for 5 minutes to carry out a color reaction. Finally, the absorbance was measured at a wavelength of 540 nm and the amount of reducing sugar was calculated, i.e., the activity of the xylanase in the formulation was measured. Among them, 1 active unit (U) is defined as the amount of the enzyme can hydrolyze 1 micromolar of reducing sugar per minute per minute (for details, see Georis et al. Sequence, overproduction and purification of the family 11 endo-β- 1,4-xylanase encoded by the xyl1 gene of Streptomyces sp. S38, Gene Vol. 237, pages 123-133).

(C) Method for measuring the yield of fine pulp:

Measurement method: 100 g of the slurry obtained after the completion of the refining was weighed, and the slurry was sieved by a flat sieve machine to obtain a fine slurry. Wherein, the flat screen machine comprises an upper sieve plate (mesh opening of about 0.1 mm) and a lower sieve (mesh opening of about 325 mesh), and the slurry which can pass through the upper sieve plate and does not pass through the lower sieve is called " Fine pulp." The fine pulp yield represents the weight percent of the slurry that passes through the upper screen and does not pass through the lower screen.

(D) Method for measuring the physical properties of paper:

Measurement method: The paper-related physical properties mentioned in the specification of the present invention are measured by the following standard measurement methods:

Basis weight: ISO 536:1995 (Paper and board-Determination of grammage).

Break length: ISO 1924-2:1994 (Paper and board-Determination of tensile properties-Part 2: Constant rate of elongation method).

Tear index: (km) Tappi T414 om-98 (Internal tearing resistance of paper (Elmendorf-type method)).

Bursting index: ISO 2758:2001 (Paper-Determination of bursting strength)

Example 1: Slurry preparation method

(a) Take an appropriate amount of rice straw and cut it into an average length of about 3 cm to about 5 cm. Put it into a pulper and add normal temperature water. After about 15 minutes of pulping, it has a double-layer sieve. The flat screen machine (the upper layer is a 0.5 mm sieve plate and the lower layer is a 325 mesh sieve) is sieved to obtain the upper layer (ie, through the upper sieve plate but not through the lower sieve) the rice straw coarse fiber material;

(b) The obtained rice straw crude fiber material is placed in a steam treatment tank for steam hydrolysis treatment, wherein the saturated vapor temperature is about 170 ° C and the treatment time is about 60 minutes. The steam-dried straw fiber material is dried at a temperature of about 105 ° C for 2 hours to remove moisture;

(c) Weigh 1000 grams of steam-treated straw fiber material and arrange it into 8 wt% straw fiber slurry, followed by a selected amount of xylanase (Xyn11B' of Neocallimastix frontalis ) And dehydrating for about 1 hour after reacting at a temperature of about 50 ° C;

(d) The enzyme-treated rice straw crude fiber material was subjected to three mechanical refining treatments by a refiner of Japan KRK Co., Ltd., after each mechanical refining treatment, the pulp was drained by a 325 mesh sieve. After the moisture is applied, the next refining process is started, and finally the slurry obtained by refining is dehydrated for use.

Example 2: Effect of enzyme dosage

Slurry 1 to 4 and comparative slurry 5 were prepared in the same manner as in Example 1, wherein the amount of the enzyme added in the step (c) was such that the concentrations in the slurry were 10, 20, 40, 80 and 0 activities, respectively. Unit / gram.

The freeness of the slurry 1 to 4 and the comparative slurry 5 were measured by the measurement method (A) and recorded as shown in Fig. 1.

As can be seen from Fig. 1, the freeness of the slurry (slurry 1 to 4) which is simultaneously subjected to the hydrolysis treatment and the enzyme treatment according to the method of the present invention is significantly lower than that of the untreated enzyme (comparative slurry 5), wherein The lower the freeness, the better the defibration effect of the fibers in the obtained slurry; and as the concentration of the enzyme increases, the freeness generally decreases gradually (from 620 ml to 575 ml), but when the enzyme concentration increases After a certain degree, there is no corresponding relationship. It is obvious that the enzyme concentration should be matched according to the process conditions.

Example 3: Effect of enzyme treatment on slurry yield

The fine pulp yields of the above-mentioned slurries 1 to 3 and the comparative slurries 5 were measured by the measurement methods (C) and (D), respectively, and the results are shown in Table 1.

As can be seen from the results of Table 1, the enzyme treatment has a significant effect on the yield of the fine pulp (the raw material of the handsheet), and the effect is more remarkable as the concentration of the enzyme used for the enzyme treatment is higher.

Example 4: Effect of hydrolysis treatment and enzyme treatment sequence

[Preparation of Paper A2 to A4 and Comparative Paper A5]

100 g of the aforementioned slurry 2 was weighed and sieved by a flat sieve machine, wherein the flat sieve machine comprises an upper sieve plate (mesh opening of about 0.1 mm) and a lower sieve (mesh opening of about 325 mesh). A portion of the fine slurry that can pass through the upper sieve plate and not through the lower sieve is obtained and dehydrated for use.

The obtained slurry was poured into about 9 liters of water and dispersed for ten minutes, and then paper was taken, that is, an appropriate amount of the slurry was poured into the slurry tank and the outlet water control valve of the slurry tank was opened, and the sieve was passed through a 150 mesh screen. After the slurry is naturally interwoven into paper, it is pressed and dried to obtain paper A2. Among them, the basis weight of the paper to be copied is preset to be about 60 g/m 2 .

In the same manner, papermaking was carried out using the slurry 3, the slurry 4, and the comparative slurry 5, respectively, to obtain paper A3, paper A4, and comparative paper A5, respectively.

The physical properties of the papers A2 to A4 and the comparative paper A5 were measured by the measurement method (E), and the results are shown in Table 2.

[Preparation of Paper B2 to B4 and Comparative Paper B5]

Slurry 2', slurry 3', slurry 4' and comparative slurry 5' were prepared in the same manner as in Example 1, except that after the enzyme treatment of the step (c) was carried out, the step (b) was started. The steam hydrolysis treatment is carried out, and after the steam hydrolysis treatment is completed, the refining treatment of the step (d) is performed. Wherein, the amount of the enzyme added in the step (c) is such that the enzyme concentrations are 20 (slurry 2'), 40 (slurry 3'), 80 (slurry 4'), and 0 (comparative slurry 5', That is, no enzyme is added to the active unit/g, and the number of refining used in the step (d) is three times.

In the same manner as [Paper A2 to A4 and preparation of Comparative Paper A5], papermaking was carried out using the slurry 2', the slurry 3', the slurry 4', and the comparative slurry 5' to prepare the paper B2, respectively. Paper B3, paper B4, and comparison paper B5 were measured for physical properties by measurement method (E), and the results are shown in Table 3.

From the results of Tables 2 and 3, it is known that the enzyme treatment of the non-wood fiber before the refining treatment can improve the physical properties of the paper prepared by the slurry, and the enzyme treatment, before or after the hydrolysis treatment. The higher the concentration of the enzyme used, the more obvious the effect.

Example 5: Effect of non-wood fiber material types

[Preparation of Paper C5 to C7]

Slurry 5", slurry 6" and slurry 7" were prepared in the same manner and in the same manner as in [Paper B2 to B4 and Comparative Paper B4 Preparation], except that straw was used as the non-wood fiber material. The amount of the enzyme added in the step (c) is such that the enzyme concentrations are 0 (slurry 5"), 100 (slurry 6"), and 200 (slurry 7") activity units/gram, respectively.

Then, in the same manner as in [Paper A2 to A4 and Preparation of Comparative Paper A5], papermaking was carried out using the slurry 5", the slurry 6" and the slurry 7" to separately produce the paper C5, the paper C6, and the paper. C7, and the physical properties were measured by the measurement method (E), and the results are recorded in Table 4.

[Preparation of Paper D2 to D4]

A slurry 2", a slurry 3" and a slurry 4" were prepared in the same manner as in Example 1, except that a straw was used as the non-wood fiber material. The amount of the enzyme added in the step (c) was such that The enzyme concentrations were 20 (slurry 2"), 40 (slurry 3"), and 80 (slurry 4") activity units/gram, respectively.

In the same manner as in [Paper A2 to A4 and Preparation of Comparative Paper A5], paper 2", slurry 3" and slurry 4" are used for paper making to separately produce papers D2, D3 and paper D4, The physical properties were measured by the measurement method (E), and the results are reported in Table 5.

It can be seen from the results of Tables 4 and 5 that, by the combination of the hydrolysis treatment and the enzyme treatment, the method of the present invention can use other non-wood fiber materials (such as wheat straw) as the pulp raw material to provide paper with good physical properties, and the same process. Arrangement, the higher the concentration of enzyme used in enzyme treatment, the more obvious the effect.

In summary, the method of the present invention uses a non-wood fiber material to replace the wood fiber material used in the conventional method to prepare a paper pulp, which not only reduces the consumption of wood fiber material, but also non-wood fiber which is not economical. Recycling of materials (such as rice straw, straw, etc.) into renewable resources; and hydrolysis treatment of a non-wood fiber material and an enzyme treatment can improve the dissociation efficiency of the fiber, thereby reducing the consumption of subsequent refining power and increasing the fiber yield. Physical properties with paper.

The above embodiments are merely illustrative of the principles and effects of the present invention, and are illustrative of the technical features of the present invention and are not intended to limit the scope of the present invention. Any changes or arrangements that can be easily accomplished by those skilled in the art without departing from the technical principles and spirit of the invention are within the scope of the invention. Accordingly, the scope of the invention is set forth in the appended claims.

Figure 1 is a graph showing the relationship between the freeness of the slurry prepared according to the method of the present invention and the enzyme dosage.

Claims (5)

A mechanical pulping process for making a non-wood fiber slurry, comprising: providing a non-wood fiber material, which is an annual grass crop; treating the non-wood fiber material with a chemical containing from about 140 ° C to about 180 ° C. For about 10 minutes to about 180 minutes; before or after the steam treatment, the non-wood fiber material is subjected to an enzyme treatment by a xylanase; and after the steam treatment and the enzyme treatment, the non-wood fiber material is subjected to A mechanical refining treatment to produce the non-wood fiber slurry, wherein the mechanical refining treatment comprises refining the enzyme-treated non-wood fiber material with a refiner. The method of claim 1, wherein the non-wood fiber material is selected from the group consisting of rice straw, straw, bagasse, cotton stalk, linen, and combinations thereof. The method of claim 1, wherein the xylanase is selected from the group consisting of Trichoderma, Actinomyces, Aspergillus, Brachypodium, Bacillus, Cellulomonas, Capillaris Genus, Mycelium, Clostridium, Filamentous, Humicola, Neocallimastix , Nocardia, Ruminococcus, Schizophyllum, Streptomyces Genus, Thermomonospora, Thermophilic fungi, and combinations thereof. The method of claim 3, wherein the xylanase is selected from the group consisting of the new genus. The method of claim 4, wherein the xylanase is selected from the group consisting of rumen fungi ( Neocallimastix frontalis ).