Mycelium fiberboard and its manufacturing method

Abstract

The method for producing mycelium fiberboard of the present invention uses low-cost and fast-growing mycelium as raw material, which replaces wood chips, and the production process is simple and easy to accelerate. The obtained mycelium fiberboard shows excellent performance in various indicators and is environmentally friendly. [Solution] This is a method for producing a type 1 mycelium fiberboard. First, 1-2-year-old mycelium with a humidity of 50-70% is cut into 2-3cm lengths to obtain cut mycelium. The cut mycelium is steamed with high-pressure steam to obtain soft steamed mycelium. The steamed mycelium is mechanically fiberized and adhesive is added to obtain adhesive-coated mycelium fiber. The adhesive-coated mycelium fiber is dried at 120-160℃ to obtain dried mycelium fiber. The dried mycelium fiber is laid, leveled, and pre-pressed to obtain the mycelium fiberboard base material. The mycelium fiberboard base material is then hot-pressed to form the final mycelium fiberboard.

Description

Technical Field

[0001] The present invention relates to the field of fiberboard technology, and in particular, to a kind of mushroom grass fiberboard and its manufacturing method.

Background Art

[0002] China is the largest producer and exporter of engineered wood products. Every year, the demand for wood far exceeds its production. Engineered wood products are essential for the production and maintenance of our daily life, playing an important role in both the national economy and individual material lifestyles. In recent years, the depletion of forest resources and the increasing environmental awareness have required the industry to save wood resources through efficient utilization, and the production and use of engineered wood products have become the main means to achieve this.

[0003] Fiberboards mainly utilize wood and its processing by-products or non-wood materials. The fibers are processed, combined with adhesives and other additives, and then hot-pressed to form boards with excellent cost-effectiveness and processability. The demand for fiberboards is increasing, and its production ranks first in the world. Materials commonly used in medium-density fiberboards include pine, spruce, fast-growing poplar, fast-growing eucalyptus, etc. Its main components are composed of wood fibers and resin adhesives.

[0004] In 2015, the government introduced a policy to completely stop commercial logging in natural forests. As a result, the cost of wood gradually increased, and the contradiction between supply and demand worsened. People began to search for substitutes for wood-based materials. Currently, non-wood materials such as sugarcane are being used, but there are problems such as seasonal fluctuations in raw material procurement and high procurement costs, making large-scale production difficult. Furthermore, environmental factors during the procurement season have a significant impact, causing the quality of raw materials to become unstable. Due to the physical and chemical properties of sugarcane, it is impossible to produce high-quality medium-density fiberboard. In addition, attempts have been made to use herbaceous plants as substitutes for wood-based materials in the production of fiberboard, but fiberboards that meet the quality and technical standards required by national and industrial regulations have not been successfully produced. Due to the differences in the stem structure and moisture content between woody plants and herbaceous plants, the effect of using grass as a substitute for wood has not been very good.

[0005] The rapidly growing, carbon-absorbing grass is a new variety developed through the cross-breeding of some grasses in the Poaceae family. Due to its short growth cycle, it can be harvested multiple times a year. Patent Document CN 107032668 A provides a method for producing building materials and wood substitutes using the rapidly growing, carbon-absorbing grass. The approach is as follows: (1) Harvest the rapidly growing, carbon-absorbing grass in a timely manner; (2) Pretreat the grass according to the technical requirements for producing foamed fiberboard, composite walls, lightweight bricks and tiles, flame-retardant insulation boards, wood substitutes, and paper substitutes; and (3) Produce foamed fiberboard, composite walls, lightweight bricks and tiles, flame-retardant insulation boards, wood substitutes, and paper substitutes. The products produced by this technology can replace lightweight materials such as composite materials and EPS foam plastics. They have a beautiful appearance, good sealing performance, and buffering performance. However, the particle board has a relatively large volume and is heavier than other types of boards, so it may not be suitable as a raw material for particle board.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] Correspondingly, the inventor aims to provide a fiberboard made from natural mushroom grass as raw material and its manufacturing method. This is aimed at replacing wood-based raw materials and reducing production costs. Furthermore, the fiberboard manufactured using the manufacturing method of the present invention has high strength and little expansion in thickness due to water absorption.

Means for Solving the Problems

[0008] To achieve the above object, the inventor provides, in a first aspect of the invention, a manufacturing method of a mushroom grass fiberboard. This manufacturing method includes the following steps: Cutting: Cut 1- to 2-year-old mushroom grass with a moisture content of 50-70% into lengths of 2-3 cm to obtain the cut mushroom grass. Steaming: Steam the cut mushroom grass under high pressure to soften it and obtain the steamed mushroom grass. Fibering and Adhesive Coating: Mechanically fiberize the steamed mushroom grass using a hot grinder, and add an adhesive during the process of ejecting the fibers from the grinder to obtain mushroom grass fibers coated with the adhesive. Drying: Dry the mushroom grass fibers coated with the adhesive at 120-160 °C to obtain dried mushroom grass fibers with a moisture content of 8.0-8.5%. Spreading, Levelling, and Pre-pressing: Spread, level, and pre-press the dried mushroom grass fibers to obtain a mushroom grass fiberboard blank. The volume density of the mushroom grass fiberboard blank should be controlled within 110-130 kg / m3. The volume density of the mushroom grass fibers is approximately twice that of wood fibers, and the spreading height, levelling wind speed, wind pressure selection, and pre-pressing net bag selection for spreading, levelling, and pre-pressing the mushroom grass fibers, which have different characteristics from those of wood fibers, are different from those of wood fibers. Hot Pressing: Hot press the mushroom grass fiberboard blank to obtain a mushroom grass fiberboard.

[0009] Preferably, the mushroom grass used isLvzhou No.1 It is a variety. Lvzhou No.1 It is a kind of mushroom grass belonging to the Poaceae family and resembles reeds or thin bamboo. It is a perennial herbaceous plant with thick and multi-jointed rhizomes, erect and highly branched stems, a height of 3 - 10 m, a stem diameter of 1 - 4 cm, and large green leaves with a width of 2 - 5 cm. Lvzhou No.1 It grows rapidly, has strong covering power, requires minimal management, and is free from pests and diseases. It is suitable for planting in various soils including acidic sandy loam soil and slightly saline alkaline soil. It can be planted in dry areas, wastelands, farmlands, mountain slopes, plains, terraces, riverbanks, lake shores, sandy lands, and other places. Once planted, it can be harvested annually, and a harvest of up to 20 years is expected. After the heading stage Lvzhou No.1 's cellulose content rapidly increases to 30%, and its lignin content is 13 - 20%. The cellulose content continues to increase even in the later growth stage. The 1 - 2-year-old mushroom grass used in this invention has an optimal fiber content and fiber morphology. Experiments have shown that mushroom grass with a long growth period has a high lignin content.

[0010] Preferably, in the steaming step, the mushroom grass is steamed at a temperature of 158 - 160 °C, a steam pressure of 5.0 - 5.5 bar, and a time of 2 - 3 minutes. If the steam pressure is less than 5.0 bar, it is disadvantageous for the slurry ejection of mushroom grass fibers. If the steam pressure exceeds 5.5 bar or the steaming temperature is too high, Lvzhou No.1 the mushroom grass may burn during the steaming process, the fibers are easily broken, the strength decreases, and it may affect the performance of the fiberboard. If the steaming temperature is too low, the mushroom grass fibers will not become soft enough, which is disadvantageous for the subsequent compression and stability of the finished fiberboard.

[0011] Preferably, in the fibrillation and adhesive coating step, urea formaldehyde resin is used as the adhesive, which has a low free formaldehyde level and is an environmentally friendly adhesive. Preferably, in the drying step, a flash dryer is used for drying.

[0012] The preferred hot pressing step is carried out at a temperature of 153 - 163 °C, a pressure of 170 - 180 bar, and a duration of 18 - 22 seconds / mm. By controlling the hot pressing temperature within this range, which is lower than the hot pressing temperature of the wood fiber board, charring of the mushroom grass is effectively prevented, and it is ensured that the mushroom grass fibers are in an optimal compressed state.

[0013] Preferably, the cuttings of the mushroom grass are steamed within 2 days after cutting. If stored for more than 2 days, fermentation or mold may occur, and the raw materials may be lost.

[0014] In a second aspect of the invention, the inventor provides a mushroom grass fiber board manufactured using the preparation method described in the first aspect of the invention.

Effect of the Invention

[0015] Different from the existing technologies, the technical solution provided here provides a mushroom grass fiber board. The raw material of this fiber board uses mushroom grass, which has low cost, fast growth, high cellulose content, and desirable fiber morphology, as a substitute for wood-based materials. The preparation process is simple and easy to promote, and as a result, a fiber board with a dense layered structure, strong durability, smooth and flat surface, little deformation, clean and delicate edges is obtained. The color of the material is uniform, and the water absorption expansion rate and formaldehyde content exceed the technical indicators specified in GB / T 11718 - 2009. By using fast-growing mushroom grass as a raw material instead of wood, the long-term growth cycle of trees and the dependence on limited logging utilization in fiber board manufacturing are significantly reduced, and the contradiction between the requirements of social and economic development and the balance of the forest ecological environment is alleviated.

Embodiments for Carrying out the Invention

[0016] Embodiment 1: A 18-mm-thick mushroom grass fiber board and its manufacturing method Cutting: Cut 1.5-year-old Lvzhou No.1 mushroom grass with a moisture content of 50.2% into lengths of 2 - 3 cm. Steam treatment: Soften the cut mushroom grass with high-pressure steam. Control the steam temperature at 158 - 160 °C, the steam pressure at 5.0 - 5.5 bar, and the steam time at 2 - 3 minutes. Fiberization and Adhesive Coating: Use a hot grinder to mechanically separate the mushroom grass into fibers, and add an adhesive during the spraying of the fibers to obtain mushroom grass fibers coated with the adhesive. The amount of adhesive added is 10% of the mass of the mushroom grass after steam treatment, and urea formaldehyde resin is used. Drying: Use a flash dryer to air-dry the mushroom grass fibers coated with the adhesive at 120 - 160 °C, and the moisture content of the dried mushroom grass fibers is 8.05%. Spreading, Levelling, Pre-pressing: Spread, level, and pre-press the dried mushroom grass fibers coated with the adhesive to obtain the base of the mushroom grass fiber board. The compression ratio of the dried mushroom grass fibers after pre-pressing is 50 - 70%, the bulk density of the pre-pressed mushroom grass is controlled to 110 kg / m3, the height of the levelling roller of the base of the mushroom grass fiber board is 50 - 60% of that of wood fibers, and the height of the pre-pressed board base is about 70% of that of wood fibers. The height of the roller of the fiber board base after levelling is about 50 - 60% of the height of wood fibers, and the height of the base after pre-pressing is about 70% of the height of wood fibers. Hot Pressing: Hot press the billets of the mushroom grass fiber board at 153 °C, a pressure of 170 bar, and a time of 22 s / mm to obtain the mushroom grass fiber board.

[0017] Compared with making paper using wood chips, the method for manufacturing a mushroom grass fiber board according to the present invention uses more flexible mushroom grass. In the hot grinder, the mushroom grass is actually fiberized, simplifying the process, improving the utilization rate of the mushroom grass, and there is almost no loss of cellulose. At the same time, the mushroom grass fibers in the fiber board are coarser than traditional wood fibers, the amount of adhesive used is less, and the resulting fiber board is stronger, heavier, and more environmentally friendly. However, the inventor has discovered that the mushroom grass tends to carbonize during the manufacturing process and cellulose is lost. Therefore, the heating temperature during steam treatment, drying, and hot pressing needs to be strictly controlled below 165 °C, preferably below 163 °C.

[0018] Various properties of the mushroom grass fiber board manufactured in Embodiment 1 were tested based on GB / T11718 - 2009. The results are shown in Table 1. Table 1: Test Results of 18mm-thick Bacterial Grass Fiberboard JPEG2022267109000001.jpg68134

[0019] Embodiment 2: 12mm-thick Bacterial Grass Fiberboard and Its Manufacturing Method The differences from Embodiment 1 include the following steps: Cutting: Cut 2-year-old Lvzhou No.1 bacterial grass straw with a moisture content of 59.5% into lengths of 2 - 3 cm; Steam treatment: High-pressure steam treatment to soften the cut bacteria; the steam temperature is maintained at 158 - 160 °C, the steam pressure is maintained at 5.0 - 5.5 bar, and the steam time is maintained at 2 - 3 minutes; Fiberization and adhesive application: Mechanically decompose the steamed bacteria into fibers with a hot grinder, and spray the adhesive during the spraying process of the fibers to obtain adhesive-applied bacterial grass straw fibers. The amount of adhesive added is 14.9% urea formaldehyde resin based on the mass of the steamed bacteria; Drying: Use a flash dryer to dry the adhesive-applied bacterial grass straw fibers at 120 - 160 °C until the moisture content of the dried bacterial grass straw fibers reaches 8.5%; Spreading, leveling, and pre-pressing: Spread, level, and pre-press the dried bacterial grass straw fibers to obtain a bacterial grass fiberboard. The compression ratio of the pre-pressing is 50 - 70%, and the volume density of the bacteria after pre-pressing is controlled at 130 kg / m3. Hot pressing: Hot press the billet of the bacterial grass fiberboard. The hot pressing temperature is 158 °C, the hot pressing pressure is 180 bar, the hot pressing time is 18 s / mm, and the above-mentioned bacterial grass fiberboard is obtained.

[0020] The performance of the bacterial grass fiberboard manufactured in Embodiment 2 was tested according to GB / T11718 - 2009, and the results are shown in Table 2: Table 2. Test Results of 12mm-thick Agricultural Waste Fiberboard JPEG2022267109000002.jpg76114

[0021] Embodiment 3 - 15mm-thick Bacterial Grass Fiberboard and Its Manufacturing Method Compared with the previous two embodiments, the differences in Embodiment 3 are as follows: Cutting: Cut the 1-year-old Lvzhou No.1 fungus with a moisture content of 54.5% into pieces 2 - 3 cm long; Steam heating: Steam the cut fungus under high pressure to soften it. The steam heating temperature is 158 - 160 °C, the steam pressure is 5.0 - 5.5 bar, and the steam heating time is 2 - 3 minutes; Defibering and adhesive application: Mechanically defiber the fungus after steam heating with a hot grinder. During the process of blowing out the fibers with the hot grinder, an adhesive is added to obtain adhesive-coated fungus fibers. The amount of the added adhesive is 13.0% urea formaldehyde resin based on the mass of the steam-heated fungus; Drying: Dry the adhesive-coated fungus fibers with a flash dryer at 120 - 160 °C. The moisture content of the dried fungus fibers is 8.35%; Spreading, leveling, and pre-pressing: Spread, level, and pre-press the dried fungus fibers to obtain the material for the fungus grass fiberboard. The compression ratio of the pre-pressing is 50 - 70%, and the bulk density of the material for the fungus grass fiberboard is controlled to 125 kg / m3; Hot pressing: Hot press the material for the fungus grass fiberboard at a temperature of 163 °C, a pressure of 175 bar, and a hot pressing time of 20 s / mm to obtain the fungus grass fiberboard.

[0022] Embodiment 4 - Fungus Grass Fiberboard with a Thickness of 18 mm and Its Manufacturing Method The difference from Embodiment 1 lies in the steam heating process where the cut fungus grass is softened by high-pressure steam heating. The steam heating temperature is controlled at 150 °C, the steam pressure is 4.8 bar, and the steam heating time is 5 minutes. Since the steam heating temperature is low, the fungus grass fibers do not become soft enough, and the bulk density becomes small. As a result, even if the subsequent processes are the same, the density of the obtained fungus grass fiberboard is low, and the values of the internal bond strength, water absorption thickness swelling rate, and surface bond strength are all lower than those of the fungus grass fiberboards obtained in Embodiments 1 - 3.

[0023] Embodiment 5 - Fungus Grass Fiberboard with a Thickness of 18 mm and Its Manufacturing Method The difference from Embodiment 1 lies in the steam heating process where the cut mushroom grass is softened by high-pressure steam heating. The steam heating temperature is controlled at 170 °C, the steam pressure is 6 bar, and the steam heating time is 3 minutes. Since the steam heating temperature and steam pressure are excessively high, the mushroom grass fibers suffer losses due to carbonization, which affects the blowing process. As a result, even if the subsequent processes are the same, the obtained mushroom grass fiberboard has lower values of flexural modulus of elasticity, internal bond strength, water absorption thickness swelling rate, and surface bond strength than those of the mushroom grass fiberboard obtained in Embodiments 1-3.

[0024] Embodiment 6 - Wood Fiberboard with a Thickness of 18 mm and Its Manufacturing Method In this embodiment, chips of fast-growing Eucalyptus saligna wood are used as raw materials. The boiling process is replaced by a hot grinding process that controls the temperature at 172 - 175 °C, the boiling pressure at 7.5 - 8.0 bar, and the boiling time at 4 - 5 minutes. In the drying process, the moisture content of the wood fibers is controlled at 9.0 - 9.5%. When forming the mat, the height of the leveling roller for the wood fiberboard mat is 1.6 - 2 times the height of the mushroom grass fiberboard mat, and the height of the pre-pressed wood fiberboard mat is 1.4 - 1.5 times that of the mushroom grass fiberboard. In the hot pressing process, the hot pressing temperature of the wood fiberboard is 165 - 175 °C, the maximum hot pressing pressure is 185 - 195 bar, and the hot pressing time is 15 - 18 s / mm. Various test indexes of the wood fiberboard obtained by the above manufacturing method also meet the standards of GB / T11718 - 2009.

[0025] However, the inventor discovered through calculations that 10 m3 of fiberboard can be produced from 15 tons of 5-year-old wood, and 10 m3 of fiberboard can also be produced from 15 tons of 2-year-old mushroom grass materials. From the perspective of the planting cycle, the output rate of mushroom grass materials and the conversion rate of fiberboard are 2.5 times that of wood materials. From the perspective of logging and utilization, mushroom grass can be harvested multiple times for each planting, and the investment costs of labor and fertilizers are low. From the perspective of the sustainability of the ecological environment, the replacement of wood materials with mushroom grass in fiberboard production effectively contributes to the conservation of forest trees and promotes the sound and sustainable development of the ecological environment. Therefore, the technical solution of this invention has advanced technology and excellent economic and social benefits.

[0026] In this document, terms such as "first" and "second" are used only to distinguish one entity or operation from others, and do not necessarily indicate an actual relationship or order between these entities or operations. Also, "include", "including", or its variations are intended to have a non-exclusive implication, and for a process, method, item, or terminal device to include a set of elements means that it includes not only the explicitly listed elements, but also other elements that are inherently present in such a process, method, item, or terminal device. Unless otherwise specified, the use of terms such as "greater than", "less than", "exceeding" does not include the specified number, and terms such as "above", "below", "within" include the specified number.

[0027] The invention disclosed and described for specific embodiments is applicable to numerous other embodiments whose principles will be apparent to those skilled in the art. Therefore, the invention should be limited by the appended claims.

Claims

1. a cutting step of cutting 1-2 year old fungus grass with a humidity of 50-70% into a length of 2-3 cm to obtain cut fungus grass; A steaming process in which the cut mushrooms are steamed with high-pressure steam to soften them and obtain steamed mushrooms; A fiberization process in which the steamed fungus grass is mechanically fiberized using a hot grinder; an adhesive application step in which an adhesive is added during the process of blowing the fibers out of the grinder to obtain adhesive-coated fungus grass fibers; a drying step of drying the adhesive-coated fungus grass fiber at 120-160°C to obtain dry fungus grass fiber with a humidity of 8.0-8.5%; A laying, leveling and pre-pressing process in which the dried grass fiber is laid, leveled and pre-pressed to obtain the base material of the grass fiberboard; A hot pressing process of hot pressing the base material of the grass fiberboard to obtain the grass fiberboard, The volume weight of the base material of the grass fiberboard in the laying, leveling and pre-pressing process is 110-130kg / m 3 A method for producing a fungus fiberboard, characterized in that the fungus fiberboard is controlled by the above method.

2. 2. The method according to claim 1, wherein the fungus used is No. 1 fungus.

3. 2. The method according to claim 1, characterized in that the steaming temperature in the steaming step is 158-160°C, the steam pressure is 5.0-5.5 bar, and the steaming time is 2-3 minutes.

4. 2. The method according to claim 1, wherein a urea-formaldehyde resin is used as the adhesive in the adhesive application step.

5. 2. The method according to claim 1, wherein the drying step is performed using a flash dryer.

6. The manufacturing method according to claim 1, characterized in that the dried fungus grass fiber is compressed at a compression ratio of 50-70% in the spreading, leveling and pre-pressing process.

7. 2. The method according to claim 1, wherein in the heat pressing step, the heat pressing temperature is 153-163° C., the heat pressing pressure is 170-180 bar, and the heat pressing time is 18-22 sec / mm.

8. The method according to claim 1, characterized in that the cut fungus grass is steamed within 2 days.

9. A method for producing a mycelium fiberboard produced by the method according to any one of claims 1 to 8.

10. The density of the fungus fiberboard is 730-860kg / m 3 The method according to claim 9,

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