Pulp manufacturing method, paper manufacturing method, compressed material for pulp manufacturing

Abstract

Provided is a pulp production method in which productivity is less likely to be deteriorated even when a plant belonging to the family Palmae is used. The pulp production method is a method in which a woody material is defibrated by a cooking treatment using an aqueous alkaline solution. The woody material comprises a compressed material produced by compressing a pulverized product of a plant belonging to the family Palmae and having a specific gravity of 0.35 to 1.30 inclusive and a water content of 25% by mass or less. The compressed material preferably has a surface area of 15 cm2 or less. The pulverized product preferably comprises a pulverized material having a size with a length of 0.6 mm to 40.0 mm inclusive and an outer diameter of 0.08 mm to 1.5 mm inclusive. The content of the pulverized material is preferably 70% by mass or more per the whole mass of the pulverized product.

Description

[Technical Field]

[0001] The present disclosure relates to a method for producing pulp, a method for producing paper, and a compressed product for pulp production. More particularly, the present disclosure relates to a method for producing pulp, a method for producing paper, and a compressed product for pulp production using palm plants. [Background technology]

[0002] Patent Document 1 describes the production of pulp using petioles of palm plants. Specifically, it describes a pulp bleaching method in which oil palm petioles are kraft cooked to a kappa number in the range of 18 to 40, then delignified with oxygen, and further treated in a multi-stage bleaching process including a hydrogen peroxide treatment step.

[0003] Patent Document 2 describes the production of pulp using trunks of palm plants. Specifically, the document describes a pulp production method including at least an oxidation step in which a chemical solution containing nitric acid is impregnated into a raw material in an atmospheric pressure atmosphere to make the raw material porous, and a cooking step in which a chemical solution containing caustic soda is impregnated into the porous raw material in an atmospheric pressure atmosphere while bringing the raw materials into contact with each other using a vortex flow, thereby separating the fibers and lignin from the porous raw material and untangling the fiber bundles. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 8-311789 [Patent Document 2] International Publication No. 2010 / 147118 Summary of the Invention

[0005] Palm plants have a high moisture content and are prone to decay, which makes them difficult to store. Palm plants also have a low apparent specific gravity, which makes them inefficient to transport. Therefore, when palm plants are used to produce pulp for papermaking using the manufacturing methods described in Patent Documents 1 and 2, productivity tends to decrease.

[0006] The present disclosure aims to provide a method for producing pulp that is less likely to reduce productivity even when palm plants are used. The present disclosure also aims to provide a method for producing paper using pulp obtained by the pulp production method, and a compressed product for pulp production that is used in the pulp production method.

[0007] A pulp manufacturing method according to one embodiment of the present disclosure is a pulp manufacturing method in which woody material is defibrated by a cooking treatment using an alkaline aqueous solution. The woody material includes a compressed product obtained by compressing crushed material of a palm plant, the compressed product having a specific gravity of 0.35 to 1.30 and a moisture content of 25% by mass or less.

[0008] A paper manufacturing method according to one embodiment of the present disclosure includes a pulping step of manufacturing pulp by the pulp manufacturing method, and a step of obtaining paper by forming and drying the pulp.

[0009] A compressed material for pulp production according to one embodiment of the present disclosure is a compressed material obtained by compressing pulverized material of a palm plant. The compressed material for pulp production has a specific gravity of 0.35 or more and 1.30 or less, and a moisture content of 25% by mass or less. DETAILED DESCRIPTION OF THE INVENTION

[0010] (Embodiment) (1) Overview The pulp manufacturing method according to this embodiment involves defibrating woody material by a cooking treatment using an alkaline aqueous solution. The woody material includes a compressed product obtained by compressing pulverized material from a palm plant. The compressed product has a specific gravity of 0.35 to 1.30. The moisture content of the compressed product is 25% by mass or less.

[0011] In this embodiment, the specific gravity of the compressed material obtained by compressing the pulverized material of the palm family plants is 0.35 or more and 1.30 or less, thereby increasing the bulk density of the palm family plants and improving the transportation efficiency of the palm family plants. Furthermore, in this embodiment, the moisture content of the compressed material obtained by compressing the pulverized material of the palm family plants is 25% by mass or less, making it resistant to corrosion and providing good storage properties. Therefore, the pulp production method of this embodiment does not reduce pulp productivity even when palm family plants are used.

[0012] (2) Details <Compressed material for pulp manufacturing> The compressed material for pulp production according to this embodiment is a compressed product of dried pulverized material from multiple palm family plants. That is, palm cuttings and crushed pieces, which are pulverized material from palm family plants, are used as raw materials. These are dried and then compressed together in multiple batches to obtain a compressed material for pulp production (compressed biomass material) made from renewable biological resources (palm family plants). The compressed material for pulp production has improved transportability and productivity compared to when pulverized material from palm family plants is not compressed. Furthermore, the use of dried pulverized material prevents decay, increasing the material yield rate and improving productivity.

[0013] The type of palm plant used for the compressed material used in pulp production is not particularly limited, but it can also be the bougainvillea, coconut palm, date palm, sago palm, acai, palm oil palm, etc. Furthermore, the parts that can be used are not particularly limited, but can be the trunk, leaves, fruit, bunches, seeds, etc.

[0014] Palm plants are crushed and dried, and then compressed. The order of crushing and drying may be arbitrary, or they may be performed simultaneously. The method for crushing palm plants is not particularly limited, but may be performed using a chipper, for example. Drying the crushed material to a moisture content of 25% by mass or less is preferable, as this prevents decay.

[0015] The ground material of a palm family plant is an aggregate of fibrous materials (including powdery materials) obtained by grinding the above-mentioned usable parts of a palm family plant. The ground material of a palm family plant preferably contains vascular tissue of a palm family plant. Vascular tissue of a palm family plant is tissue that transports water and nutrients necessary for the growth of a palm family plant, and includes xylem and phloem. Xylem is a transport pathway for water and nutrients absorbed from the roots, and has vessels and tracheids. Phloem is a transport pathway for nutrients created by the leaves, and has phloem tubes.

[0016] The palm plant pulverized material preferably contains pulverized material of a predetermined size. The pulverized material preferably has a length of 0.6 mm to 40.0 mm and an outer diameter of 0.08 mm to 1.5 mm (hereinafter, pulverized material within this range will be referred to as "good-sized pulverized material"). If the length of the pulverized material is shorter than 0.6 mm or the outer diameter of the pulverized material is smaller than 0.08 mm, the palm plant vascular tissue contained in the pulverized material will be too fine, resulting in a short average length of the resulting pulp and a decrease in paper strength. Furthermore, if the length of the pulverized material is longer than 40.0 mm or the outer diameter of the pulverized material is greater than 1.5 mm, the shape of the pulp constituting the paper will be too coarse, resulting in a decrease in paper surface smoothness. Specifically, if the length of the pulverized material is 0.6 mm to 40.0 mm and the outer diameter of the pulverized material is 0.08 mm to 1.5 mm, high-quality pulp will be obtained.

[0017] The length of the pulverized material is more preferably within the range of 5.0 mm to 40.0 mm, and the outer diameter is more preferably within the range of 0.3 mm to 1.5 mm. This makes it less likely that the paper strength will decrease and the paper surface smoothness will decrease. The length and outer diameter of the pulverized material can be obtained by photographing a predetermined amount of pulverized palm plant material or observing it with a magnifying glass and measuring the length and outer diameter.

[0018] The content of the finely sized ground material is preferably 70% or more by mass of the total amount of ground palm plant material. If this mass ratio is lower than 70%, the amount of pulp (fiber component) with a length that contributes to the strength of the paper will be reduced, making the paper more likely to have low strength. In addition, since the proportion of palm plant parenchyma tissue, which is the main component of the fine powder, is increased in the ground palm plant material, the amount of alkaline aqueous solution used during the cooking process is likely to increase, which may result in reduced pulp productivity. The content of the finely sized ground material is more preferably 80% or more by mass of the total amount of ground palm plant material, and most preferably 100%.

[0019] The pulverized palm plant material is preferably obtained by pulverizing a palm plant and then classifying it to reduce the amount of palm plant parenchyma tissue. In other words, the pulverized palm plant material preferably contains small pulverized material composed primarily of palm plant parenchyma tissue and large pulverized material composed primarily of palm plant vascular tissue, and is obtained by reducing the amount of these small pulverized material. Palm plant parenchyma tissue is tissue composed of palm plant parenchyma cells. Palm plant parenchyma tissue includes assimilation tissue, secretory tissue, storage tissue, etc., and has physiological functions such as synthesis, decomposition, and storage.

[0020] If a palm family plant parenchyma tissue is contained in a large amount in a pulverized palm plant, the amount of alkaline aqueous solution used tends to increase, which may make it difficult to produce pulp stably. Therefore, in this embodiment, the amount of palm family plant parenchyma cell tissue is reduced in order to obtain a pulverized palm plant with a low content of palm family plant parenchyma cell tissue. As a method for reducing the amount of palm family plant parenchyma cell tissue, a method of removing small-sized pulverized material by classification can be used. Methods of classification include sieving, air sorting, and water bathing, but are not particularly limited thereto.

[0021] The pulverized palm plant material is preferably prepared by pulverizing a palm plant and then washing it with water to reduce the amount of sugars. In this case, poor drying during the papermaking process can be reduced. Here, sugars refer to monosaccharides, disaccharides, and polysaccharides (including oligosaccharides). Examples of monosaccharides include fructose, ribose, arabinose, rhamnose, xylulose, and deoxyribose. Examples of disaccharides include sucrose, maltose, trehalose, turanose, lactulose, maltulose, palatinose, gentiobiulose, melibiulose, galactosucrose, rutinulose, and planteobiose. Examples of polysaccharides include starch, agarose, alginic acid, glucomannan, inulin, chitin, chitosan, hyaluronic acid, glycogen, and cellulose. Examples of oligosaccharides include fructooligosaccharides, galactooligosaccharides, mannanoligosaccharides, and stachyose. It is preferable to reduce the amount of sugars by 50% or more from the state before washing. It is also preferable to reduce the amount of ash when washing palm plants, since this can reduce the occurrence of process problems caused by ash during the cooking process described below.

[0022] The compressed product for pulp production of this embodiment is obtained by compressing and integrating multiple dried pulverized materials. That is, the compressed product for pulp production of this embodiment includes dried pulverized materials of multiple palm plant (biomass) and is a compressed product obtained by integrating these pulverized materials. The shape of the compressed product for pulp production may be, but is not particularly limited to, pellets, tablets, briquettes, blocks, plates, etc. Pellet-shaped compressed products can be obtained using known pelletizers such as flat die molding machines and ring die molding machines. Tablet-shaped compressed products can be obtained using known tablet molding machines that use a mold with a cavity corresponding to the shape of the compressed product. Briquette-shaped compressed products can be obtained, for example, using a known briquetting machine, such as a mold that is open at the front and back, where a pulverized material is placed into one open side with an already-formed compressed product, and the pulverized material is compressed by applying pressure from the other open side while the compressed product is advanced. Block-shaped compressed materials can be obtained using known compactors, such as a uniaxial compactor, which places the crushed material into a frame with one side open and applies pressure to the crushed material from the open side to compress it, or a triaxial compactor, which compresses it from three sides. Plate-shaped compressed materials can be obtained by stacking the crushed material to form a mat and compressing the mat in the thickness direction. When compressing the crushed material, no adhesive is used; the material is integrated by compression force, but adhesives may be used as long as they do not interfere with defibrating the wood material.

[0023] The surface area of ​​the compressed material for pulp production in this embodiment is 15 cm 2 In this case, when the wood material containing the compressed material for pulp production is defibrated by cooking, the chemical solution used in the cooking process is more likely to penetrate into the compressed material for pulp production, and the defibration of the wood material is more likely to proceed. Note that the lower limit of the surface area of ​​the compressed material for pulp production is not particularly set, but it is preferred that it be 1 cm or less for ease of handling. 2 It is preferable that it is greater than .

[0024] The specific gravity of the compressed product for pulp production in this embodiment is preferably in the range of 0.35 to 1.30. If the specific gravity of the compressed product for pulp production is less than 0.35, the mechanical durability of the compressed product for pulp production decreases, making it more susceptible to crumbling or cracking during transportation. If the specific gravity of the compressed product for pulp production is greater than 1.30, the chemical solution (such as an alkaline aqueous solution) is less likely to penetrate during cooking, and sufficient defibration may not be achieved. Even if defibration is achieved, the fibrous tissue constituting the pulverized palm plant material may be compressed and damaged, resulting in an increase in fine fibers, which may reduce the strength properties of the final paper. The specific gravity of the compressed product for pulp production is more preferably in the range of 0.40 to 1.30. If the specific gravity is less than 0.40, the bulk density increases, which causes volumetric rate-limiting behavior during transportation, resulting in an increased number of round trips during transportation. Therefore, the specific gravity of the compressed biomass product is more preferably in the range of 0.40 to 1.30.

[0025] The compressed product for pulp production of this embodiment preferably has a moisture content of 25% by mass or less, more preferably 20% by mass or less. If the moisture content is higher than 25% by mass, the shape retention of the compressed product for pulp production is likely to decrease, and at the same time, mold is likely to grow and the product is likely to spoil, which also tends to decrease storage stability. There is no particular lower limit for the moisture content of the compressed product for pulp production, and it is sufficient if it is 0% by mass or more.

[0026] Thus, when the compressed product for pulp production of this embodiment has a specific gravity in the range of 0.35 to 1.30, storage properties and mechanical durability are improved, and the fibrous tissue of the palm family plants is less likely to be damaged by compression. Furthermore, when the compressed product for pulp production of this embodiment has a moisture content of 25% by mass or less, mold and decay are less likely to occur, and storage properties are improved. Note that, in this disclosure, "mechanical durability" refers to shape retention, and refers to the property of being less likely to crumble or break during storage.

[0027] <Pulp manufacturing method> The pulp manufacturing method according to this embodiment involves defibrating wood material containing the compressed material for pulp manufacturing by a cooking treatment using an alkaline aqueous solution. By using the compressed material for pulp manufacturing, the pulp manufacturing method according to this embodiment can easily produce pulp of stable quality even when palm trees with low bulk density are used. The compressed material for pulp manufacturing alone may be used as the wood material, or the compressed material for pulp manufacturing may be used in combination with ground material of tropical wood or coniferous trees conventionally used in paper manufacturing.

[0028] The alkaline aqueous solution is an aqueous solution containing an alkaline component such as sodium hydroxide, sodium sulfide, a mixture thereof, etc. The concentration of the alkaline component is not particularly limited, but is preferably 0.5% by mass or more and 10% by mass or less.

[0029] Cooking is a process in which woody materials are treated with a high-temperature alkaline aqueous solution to dissolve and separate the lignin contained in the woody materials and break them down into wood fibers (mainly vascular tissue of palm plants). There are no particular restrictions on the cooking conditions, but for example, the reaction can be carried out in a digester or autoclave using an alkaline aqueous solution at a temperature of 90 to 180°C.

[0030] After defibration, the wood fibers are dried as needed. Drying is a process for reducing the moisture content of the defibrated wood fibers. Drying can be carried out by supplying hot air to the defibrated wood fibers. There are no particular restrictions on the moisture content of the dried wood fibers, but it is preferable that the moisture content be 20 mass% or less of the total amount of bone-dried wood fibers, for example.

[0031] The wood fibers thus obtained can be used as pulp.

[0032] <Paper manufacturing method> The paper manufacturing method according to this embodiment comprises a pulping step and a paper-obtaining step. The pulping step is a step of producing pulp using the above-described pulp manufacturing method. The paper-obtaining step is a step of making paper from the pulp obtained in the pulping step and drying it. Papermaking can be carried out using, for example, a Fourdrinier paper machine, a cylinder paper machine, or a hand-made paper machine. Drying is carried out by using a dryer to dry the made pulp until it reaches a predetermined moisture content.

[0033] (summary) The first aspect is a method for producing pulp by defibrating woody material through a digestion treatment using an alkaline aqueous solution. The woody material includes a compressed material obtained by compressing crushed material from a palm plant, and having a specific gravity of 0.35 to 1.30 and a moisture content of 25% by mass or less.

[0034] According to this embodiment, palm plants have good storage properties and are transported efficiently, which is advantageous in that pulp productivity is not likely to decrease even when palm plants are used.

[0035] A second aspect is the method for producing pulp according to the first aspect, wherein the surface area of ​​the compressed product is 15 cm 2 The following is the result.

[0036] According to this embodiment, the chemical solution (such as an alkaline aqueous solution) is more likely to penetrate into the compressed material during the cooking treatment, and defibration is more likely to proceed.

[0037] In a third aspect, the method for producing pulp according to the first or second aspect is characterized in that the pulverized material contains pulverized material having a length of 0.6 mm to 40.0 mm and an outer diameter of 0.08 mm to 1.5 mm, and the content of pulverized material of the above size is 70 mass % or more relative to the total mass of the pulverized material.

[0038] According to this embodiment, the amount of powdery pulp is reduced, and the strength of the paper is less likely to decrease.

[0039] A fourth aspect is the method for producing pulp according to any one of the first to third aspects, wherein the pulverized material is obtained by pulverizing the palm plant and then classifying it to reduce the amount of parenchyma tissue.

[0040] According to this embodiment, the parenchyma tissue is removed, making it possible to reduce the amount of alkaline aqueous solution used, thereby improving pulp productivity.

[0041] A fifth aspect is the method for producing pulp according to any one of the first to fourth aspects, wherein the pulverized material is obtained by pulverizing the palm plant and then washing it with water to reduce the amount of sugars.

[0042] According to this embodiment, pulp with reduced sugar content can be obtained, and poor drying during the papermaking process can be reduced.

[0043] A sixth aspect is a method for producing paper, comprising a pulping step of producing pulp by the pulp production method, and a step of obtaining paper by forming and drying the pulp.

[0044] According to this embodiment, there is an advantage that pulp can be produced efficiently and paper productivity is improved.

[0045] A seventh aspect is a compressed material for pulp production, which is a compressed material obtained by compressing pulverized material of a palm plant. The compressed material for pulp production has a specific gravity of 0.35 to 1.30 and a moisture content of 25% by mass or less.

[0046] According to this embodiment, palm plants have good storage properties and are transported efficiently, which is advantageous in that pulp productivity is not likely to decrease even when palm plants are used. [Example]

[0047] Example 1 As a raw material for biomass paper pulp, the trunk part (OPT) was extracted from oil palm and put into a chipper to obtain biomass pulverized material of 20mm to 40mm size.

[0048] Thereafter, foreign matter was removed using a foreign matter remover, the pulverized material was washed with water, dehydrated, and then passed through a jet dryer to dry it to a predetermined moisture content.

[0049] The biomass was then sieved through a 10-mesh sieve and then through a 200-mesh sieve to reduce the proportion of parenchyma cells, yielding a biomass pulverized product (pulverized palm plant) with an average length of 25 mm, an average outer diameter of 1.0 mm, and a content of 80% fine-sized pulverized material. This pulverized product was then washed with water to reduce the amount of sugars.

[0050] This pulverized material was used as a raw material and compressed into cylindrical pellets with a diameter of 10 mm and a length of 50 mm using a pelletizer, yielding a compressed biomass material (compressed material for pulp production) with a specific gravity of 0.95 and a moisture content of 12%.

[0051] This compressed product and a 5% aqueous sodium hydroxide solution were placed in an autoclave so that the liquid ratio was 1:4 (1 mass of compressed product to 4 masses of 5% aqueous sodium hydroxide solution).

[0052] Next, the autoclave was heated and maintained at 170°C and 0.8 MPa for 2 hours, after which the autoclave was depressurized and returned to normal pressure. The contents were then filtered through a polyester bag with an opening of approximately 100 μm, washed with water, removed, and dried to obtain pulp.

[0053] Example 2 Using OPT as the raw material for pulp, a pulverized product having an average length of 30 mm, an average outer diameter of 1.2 mm, and a content of good-sized pulverized product of 85% was produced in the same manner as in Example 1.

[0054] The pulverized material was then compressed using a briquette to form briquettes with a diameter of 50 mm and a length of 40 mm, yielding a compressed biomass material (compressed material for pulp production) with a specific gravity of 1.00 and a moisture content of 11%. Pulp was obtained in the same manner as in Example 1, except that this compressed biomass material was used.

[0055] Example 3 Using OPT as the raw material for pulp, a pulverized product having an average length of 20 mm, an average outer diameter of 1.5 mm, and a content of good-sized pulverized product of 90% was produced in the same manner as in Example 1.

[0056] The pulverized material was then compressed using a triaxial volume reducer to produce a 40 mm square block of compressed material, yielding a compressed biomass material (compressed material for pulp production) with a specific gravity of 0.90 and a moisture content of 13%. Pulp was obtained in the same manner as in Example 1, except that this compressed biomass material was used.

[0057] Example 4 Coconut trunks were used as the raw material for pulp, and a pulverized product with an average length of 23 mm, an average outer diameter of 1.0 mm, and a content of good-sized pulverized material of 80% was produced using the same process as in Example 1.

[0058] The pulverized material was then compressed using a pelletizer to produce cylindrical pellets with a diameter of 10 mm and a length of 50 mm, yielding a compressed biomass material (compressed material for pulp production) with a specific gravity of 1.05 and a moisture content of 12%. Pulp was obtained in the same manner as in Example 1, except that such a compressed biomass material was used.

[0059] Example 5 Using OPT as the raw material for pulp, a pulverized product having an average length of 20 mm, an average outer diameter of 1.0 mm, and a content of good-sized pulverized product of 85% was produced in the same manner as in Example 1.

[0060] The pulverized material was then compressed using a pelletizer to produce cylindrical pellets measuring 8 mm in diameter and 30 mm in length, yielding a compressed biomass material (compressed material for pulp production) with a specific gravity of 0.95 and a moisture content of 10%. Pulp was obtained in the same manner as in Example 1, except that such a compressed biomass material was used.

[0061] Example 6 Using OPT as the raw material for pulp, a pulverized product having an average length of 30 mm, an average outer diameter of 1.5 mm, and a content of good-sized pulverized product of 60% was produced in the same manner as in Example 1.

[0062] The pulverized material was then compressed using a pelletizer to produce cylindrical pellets with a diameter of 10 mm and a length of 50 mm, yielding a compressed biomass material (compressed material for pulp production) with a specific gravity of 1.15 and a moisture content of 10%. Pulp was obtained in the same manner as in Example 1, except that such a compressed biomass material was used.

[0063] (Comparative Example 1) Using OPT as the raw material for pulp, a pulverized product having an average length of 35 mm, an average outer diameter of 1.5 mm, and a content of good-sized pulverized product of 90% was produced in the same manner as in Example 1.

[0064] The pulverized material was then compressed using a three-axis volume reducer to produce a 40 mm square block of compressed material, yielding a compressed biomass material (compressed material for pulp production) with a specific gravity of 0.28 and a moisture content of 15%. Pulp was obtained in the same manner as in Example 1, except that this compressed biomass material was used.

[0065] (Comparative Example 2) Using OPT as the raw material for pulp, a pulverized product having an average length of 15 mm, an average outer diameter of 0.8 mm, and a content of good-sized pulverized product of 70% was produced in the same manner as in Example 1.

[0066] The ground material was then compressed using a pelletizer to produce cylindrical pellets measuring 10 mm in diameter and 50 mm in length, yielding a compressed biomass material (compressed material for pulp production) with a specific gravity of 1.40 and a moisture content of 9%. An attempt was made to obtain pulp in the same manner as in Example 1, except that this compressed biomass material was used, but defibration was insufficient and pulp usable for paper production was not obtained.

[0067] (Comparative Example 3) Using OPT as the raw material for pulp, a pulverized product having an average length of 25 mm, an average outer diameter of 1.0 mm, and a content of good-sized pulverized product of 80% was produced in the same manner as in Example 1.

[0068] The pulverized material was then compressed using a briquette to form briquettes with a diameter of 50 mm and a length of 40 mm, yielding a compressed biomass material (compressed material for pulp production) with a specific gravity of 1.10 and a moisture content of 30%. Pulp was obtained in the same manner as in Example 1, except that this compressed biomass material was used.

[0069] The pulps obtained in the above Examples and Comparative Examples 1 and 3 were used to produce paper through the following process.

[0070] 1. The dough was defibrated using a pulper at 10,000 revolutions (in accordance with JIS P8220-1).

[0071] 2. The disintegrated pulp slurry was passed through a test flat screen with an 18-cut screen (slit width: 0.3 mm) to remove coarse fibers such as undigested fibers.

[0072] 3. The pulp that passed through the screen was beaten at 10,000 rpm using a PFI mill (in accordance with JIS P8221-2).

[0073] 4. Using a standard handsheet, beaten pulp is made into a paper with a basis weight of 60 g / m 2 The paper was produced (in accordance with JIS P8222).

[0074] The evaluation results of the compressed materials, pulp, and paper in the above examples and comparative examples are shown below. The evaluation methods and criteria are as follows.

[0075] Mechanical durability evaluation The mechanical durability (DU) of the compressed biomass material after molding was measured based on the wood pellet quality standards of the Japan Wood Pellet Association. DU = (m1 / m0) x 100 (%) m0: Mass before test m1: Mass after test (judgement) A: 97.5% or more B: 96.5% or more and less than 97.5% C: Less than 96.5%

[0076] Storage evaluation The mold resistance of compressed biomass was measured based on the "JIS Z 2911 mold resistance test method." (judgement) A: 14 days or more B: 10 days or more but less than 14 days C: Less than 10 days

[0077] Screen penetration evaluation The screen passing rate S was measured when the disintegrated pulp slurry was passed through a test flat screen with an 18-cut screen (slit width: 0.3 mm). S = (m1 / m0) × 100 (%) m0: Pulp mass before passing through the screen m1: Pulp mass after passing through the screen * Pulp mass is measured in a completely dry state (when it reaches a constant weight in a 105°C dryer). (judgement) A: 95% or more B: 90% or more but less than 95% C: Less than 90%

[0078] Strength evaluation Based on "JIS P 8113 Paper and paperboard - Testing methods for tensile properties - Part 2: Constant rate of extension method", a tensile test was conducted on the paper to measure the tensile strength index. (judgement) A:35Nm / g or more B: 25Nm / g or more and less than 35Nm / g C: Less than 25 Nm / g

[0079] [Table 1]

[0080] [Table 2]

[0081] In all examples, the evaluation was A or B, and it was confirmed that there were no practical problems.

Claims

1. A method for producing pulp by defibrating wood materials by a cooking treatment using an alkaline aqueous solution, The wood material includes a compressed material obtained by compressing crushed material of a palm plant, the compressed material having a specific gravity of 0.35 to 1.30 and a moisture content of 25% by mass or less. Pulp manufacturing method.

2. The surface area of ​​the compressed product is 15 cm ２ Below is the A method for producing the pulp according to claim 1.

3. The pulverized material contains pulverized material having a length of 0.6 mm or more and 40.0 mm or less and an outer diameter of 0.08 mm or more and 1.5 mm or less, The content of the pulverized material of the size is 70% by mass or more relative to the total mass of the pulverized material. A method for producing the pulp according to claim 1.

4. The pulverized material is obtained by pulverizing the palm plant and then classifying it to reduce the amount of parenchyma tissue. A method for producing the pulp according to claim 1.

5. The pulverized material is obtained by pulverizing the palm plant and then washing it with water to reduce the amount of sugars. A method for producing the pulp according to claim 1.

6. A pulping step of producing pulp by the pulp production method according to any one of claims 1 to 5; and a step of obtaining paper by forming the pulp into paper and drying it. Paper manufacturing method.

7. It is a compressed product obtained by compressing crushed palm plant material, The specific gravity is 0.35 or more and 1.30 or less, and the moisture content is 25% by mass or less. Compressed material for pulp production.

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