CN118024372A - A highly flame-retardant and highly waterproof bamboo body self-gluing reconstructed material and a manufacturing method thereof - Google Patents

Abstract

The invention discloses a highly flame-retardant and highly waterproof bamboo self-bonding recombinant material and a manufacturing method thereof. The manufacturing method comprises the following steps: S1, performing a benzene alcohol extraction treatment on the dried bamboo shavings, and after washing, obtaining the extracted shavings unit; S2, performing an alkali solution pretreatment on the extracted shavings unit, and obtaining the pretreated shavings unit; S3, performing a drying and balancing treatment on the pretreated shavings unit, and then placing it in a sodium silicate aqueous solution for impregnation treatment, and obtaining the impregnated shavings unit; S4, performing a molding after the impregnated shavings unit is dried and balanced, and performing a molding process under the conditions of a temperature of 150-200° C. and a pressure of 10-45 MPa, and demolding after cooling to obtain the bamboo self-bonding recombinant material. The bamboo self-bonding recombinant material prepared by the invention does not need to add an adhesive in the manufacturing process, and can be formed by only one molding. The product has the advantages of high strength, weather resistance, flame retardancy, and no formaldehyde and no phenol release, and the production and manufacturing can realize the full biomass utilization of bamboo resources.

Description

A highly flame-retardant and highly waterproof bamboo body self-gluing reconstructed material and a manufacturing method thereof

Technical Field

The invention relates to the technical field of reconstituted bamboo manufacturing, and in particular to a bamboo body self-gluing reconstituted material and a manufacturing method thereof.

Background technique

Under the background of global sustainable development, bamboo, as the world's "second largest forest" resource, has been listed as a major substitute for wood, plastic and steel due to its outstanding advantages such as short growth cycle and high strength-to-weight ratio. With the continuous breakthroughs in modern bamboo processing and reorganization technology, bamboo has been processed into a variety of bamboo composite reorganization materials, such as bamboo plywood, reorganized bamboo, bamboo integrated materials and bamboo laminated materials, which have completely broken through the structural defects of bamboo itself, such as thin-walled hollow and large taper, and realized the controllable design and manufacturing of structure and specification width.

However, the existing industrial bamboo composite reconstruction technology mostly uses aldehyde and phenolic resins as adhesives. The products have the problem of indoor environmental pollution caused by the release of aldehydes and phenolic substances, which limits their scope of application. In order to break through the above technical bottlenecks, a few scholars have devoted themselves to the high-temperature molding and gluing technology of biomass materials in the past two years. Although they have overcome the high-strength green and environmentally friendly glue-free forming of bamboo reconstructed bamboo, the products still have problems such as poor weather resistance and insufficient functionality, especially the fire resistance and liquid resistance have not been significantly improved.

For example, at present, there is a method for preparing bamboo powder glue-free dense material in the prior art, which comprises crushing bamboo slices into bamboo powder after hydrothermal treatment, preheating the bamboo powder, paving it and then molding it to obtain bamboo powder glue-free dense material. In this technical scheme, the physical and mechanical properties of the powder are reduced by hydrothermal treatment, which reduces the mold rebound and improves the density of the material. To a certain extent, a green and environmentally friendly dense material is obtained without using an adhesive. However, the applicant found that in this technical scheme, the hydrothermal treatment only softens the powder and reduces the rebound deformation of the product, and has no effect on initiating the bonding free radicals required for the subsequent self-bonding process. The static bending strength of the final product is lower than 30MPa, and the 24h water absorption thickness expansion rate of the product is higher than 15%, which limits the scope of use of the product to a certain extent.

On the other hand, the existing industrially promoted bamboo composite reconstructed products have poor gluing properties due to the green and yellow bamboo, so the preparation process needs to remove the green and yellow bamboo, which ultimately leads to the maximum utilization rate of bamboo raw materials being less than 60% (the lowest is even less than 30%). Therefore, on the basis of ensuring the efficient utilization of bamboo resources, how to produce green, environmentally friendly, high-strength and functional bamboo reconstructed materials to meet the high-strength load-bearing requirements of indoor and outdoor construction, transportation and harsh environments is of practical significance for increasing the added value of bamboo products and promoting the high-quality development of my country's bamboo industry.

Summary of the invention

The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a highly flame-retardant and highly waterproof bamboo body self-adhesive reconstructed material and a manufacturing method thereof which does not require any adhesive additives and can have high strength, good water resistance, and no formaldehyde or phenol release through only one-time molding.

In order to solve the above technical problems, the present invention adopts the following technical solutions:

A method for manufacturing a highly flame-retardant and highly waterproof bamboo body self-gluing reconstructed material comprises the following steps:

S1, extracting the dried bamboo shavings with benzene alcohol, washing them, and obtaining extracted shavings units;

S2, pre-treating the extracted wood shavings units with alkali solution to obtain pre-treated wood shavings units;

S3, drying and balancing the pretreated wood particle units and then placing them in a sodium silicate aqueous solution for immersion treatment to obtain immersion wood particle units;

S4, drying and balancing the impregnated wood shavings units, and then placing them into a mold, performing a compression molding process at a temperature of 150-200° C. and a pressure of 10-45 MPa, and demolding the mold after cooling to obtain a bamboo body self-gluing reconstructed material.

As a further improvement to the above technical solution:

In the step S1, the dried bamboo shavings include the following preparation steps: preparing bamboo shavings from bamboo raw materials, drying to an air-dried state, and obtaining dried bamboo shavings.

In step S1, the bamboo raw material is one or more of bamboo green, bamboo yellow, bamboo flesh or bamboo processing residues.

Preferably, in step S1, the drying to an air-dry state is performed using a single-channel rotary drum dryer, the drying medium is superheated steam, the drying temperature is 100-110° C., the rotation speed is 30-50 r/min, and the drying time is 3-10 min.

Preferably, in step S1, the moisture content of the air-dried bamboo shavings is about 8% to 18%.

In step S1, the benzene alcohol extraction treatment includes the following steps: mixing the dried bamboo shavings with the benzene alcohol mixed solution and subjecting the mixture to microwave radiation at an intensity of 80 to 100 W for 30 to 60 minutes, and then subjecting the mixture to extraction treatment in a water bath for 1 to 2 hours. The purpose of the benzene alcohol extraction treatment is to remove organic extracts from the bamboo material to obtain purified shavings units, so as to reduce the influence of the organic extracts from the bamboo material on the subsequent self-bonding effect of the bamboo material body, and the purpose of the microwave radiation treatment is to shorten the benzene alcohol extraction treatment time to improve the extraction efficiency.

In step S1, the material-to-liquid ratio of the dried bamboo shavings to the benzene-alcohol mixed solution is 1:20-50. The material-to-liquid ratio here refers to the ratio of the mass of the bamboo shavings to the volume of the benzene-alcohol mixed solution.

Preferably, in step S1, the benzene-alcohol mixed solution is a mixed solution of benzene and alcohol, and the volume ratio of benzene to alcohol is 2:1.

Preferably, in step S1, the alcohol is ethanol.

Preferably, in step S1, after the extraction treatment, the bamboo shavings are rinsed and filtered with alcohol and deionized water in sequence.

In step S2, the alkaline solution pretreatment includes the following steps: placing the extracted wood particle units in a 5-20wt% alkaline solution, and performing chemical pretreatment for 0.5-1h at a temperature of 140-160°C to obtain pretreated wood particle units.

The purpose of alkali solution pretreatment is to achieve the purpose of selectively removing hemicellulose and part of lignin in the particle unit, so that it depolymerizes into monosaccharides, aldehydes and many other highly reactive free radical intermediates; at the same time, it effectively increases the micro-nano pore structure on the bamboo fiber cell wall, improves the permeability of the bamboo surface, provides more abundant adsorption space for the subsequent particle unit impregnation treatment, and provides a structural basis for the micro-nano structure fusion of the particle unit body self-gluing in the later stage. The alkali solution pretreatment time is controlled within the range of 0.5~1h, so that only part of the lignin in the particle unit is degraded. On the one hand, it can effectively promote its degradation into small molecules, providing a material basis for the re-polymerization under the action of "humidity-heat-force" in the later stage; on the other hand, the selective removal of bamboo cell wall materials can ensure that part of the lignin is not completely degraded, maintaining its thermoplastic melting effect in the later molding process, thereby effectively promoting the glue-free densification of the particle unit.

In step S2, the material-liquid ratio of the wood shavings unit and the alkaline solution is 1:5-10. The material-liquid ratio here refers to the ratio of the mass of the wood shavings unit material to the volume of the alkaline solution.

Preferably, in step S2, stirring is also performed during the chemical pretreatment process so that the wood chip units can fully contact with the treatment liquid to obtain a better pretreatment effect.

In step S3, the impregnation treatment includes the following steps: placing the dried pretreated wood shavings unit in a 5-30wt% sodium silicate aqueous solution, keeping it at a temperature of 40-60°C for 1-2 hours, and then taking it out to obtain the impregnated wood shavings unit.

The purpose of the impregnation treatment is to load sufficient sodium silicate into the pore structure of the cell wall of the particle unit, so that in the subsequent high-temperature molding process, the silicate anions can be dehydrated and condensed into larger micelle particles, so as to form a larger and more stable three-dimensional network structure, and then form a uniform, stable, continuous and dense protective film layer on the surface of the particle unit, so as to give the bamboo reconstructed material extremely strong water resistance, fire resistance and corrosion resistance.

Preferably, in step S3, the drying balance treatment comprises the following steps: drying the pretreated wood shavings unit by vacuum drying at 80-100° C. until the moisture content is less than 10%.

In the step S4, the holding time of the compression molding process is 20 to 70 minutes; and the demoulding process also includes curing and machining.

Preferably, in step S4, the drying balance treatment is performed using a single-channel rotary drum dryer, the drying medium is hot air, the drying temperature is 50-60° C., the rotation speed is 30-50 r/min, and the drying time is 20-60 min.

Preferably, in step S4, the target moisture content of the impregnated wood shavings unit after drying is in the range of 6% to 15%, so as to ensure the self-gluing effect of the wood shavings body in the subsequent molding process.

Preferably, in step S4, the target moisture content is 6% to 15%, which can better achieve the chemical bonding of the bamboo material and the welding fusion of the physical structure under the synergistic effect of the "wet-heat-force" multiple coupling, and effectively promote the shavings unit to achieve high-performance body self-gluing forming and manufacturing. The shavings unit can also be formed and processed at any moisture content, but it will affect the performance of the final product.

Preferably, in step S4, the mold loading refers to putting the wood shavings units into the mold cavity in batches and evenly distributing the wood shavings units in the mold cavity. The reason for feeding in batches is that the wood shavings units are light and have a large aspect ratio, and the units are easy to stick together and have poor fluidity. The powder feeding process should be careful and evenly applied to ensure that the wood shavings units loaded into the mold cavity are uniform and flat.

Preferably, in step S4, the mold is a rigid metal mold made of alloy steel forging material Cr12, and is used in combination of three components: a cavity, an upper punch, and a lower punch. The quenching/tempering heat treatment hardness of the cavity is HRC60-70, and the roughness of the inner wall of the cavity is Ra0.4; the quenching/tempering heat treatment hardness of the upper and lower punches is HRC55-60, and the surface roughness is also Ra0.4; the preferred working surface matching clearance between the cavity and the upper and lower punches is 0.05-0.08m, so as to ensure that the volatiles generated during the molding process can have an escape channel.

Preferably, in step S4, the mold should be lubricated before the wood shaving unit is loaded with materials, that is, a lubricating substance is coated on the inner wall of the cavity and the die punch working surface to facilitate the subsequent demolding process.

The substance having lubricating effect is preferably liquid paraffin or zinc stearate.

Preferably, in step S4, the compression molding is uniaxial one-time bidirectional pressurized closed compression plasticizing molding, which can effectively achieve limited lateral flow of the shaving units and promote uniform distribution of the shaving units inside the slab.

Preferably, in step S4, the cooling is cooling along with the mold, that is, a "cold-out" process is adopted. After the pressing process reaches the insulation and pressure holding time, the slab should be cooled along with the mold to below 60°C by artificial or natural cooling before the pressure relief and demolding processes can be carried out in sequence.

Preferably, in step S4, the demoulding process should uniformly apply a vibration force of a certain frequency on the upper punch pressure surface to ensure that the formed slab is completely ejected from the lower outlet of the cavity.

As a general inventive concept, the present invention also provides a highly flame-retardant and highly waterproof bamboo body self-gluing reconstructed material, which is prepared by the aforementioned preparation method. The forming strength of the bamboo body gluing reconstructed material exceeds 100MPa, the thickness expansion rate of water absorption at room temperature for 24 hours is less than 1%, and the flame retardant and smoke suppression performance reaches the flame retardant grade ( _B1 grade).

Compared with the prior art, the advantages of the present invention are:

(1) The method for manufacturing a highly flame-retardant and highly waterproof bamboo body glued reconstructed material of the present invention is based on the chemical and structural characteristics of the wood particle unit body material. Under the condition of not adding any substance, the wood particle unit after the coordinated impregnation treatment of alkali solution and sodium silicate produces multiple coupling effects of chemical bonding, lignin thermoplastic fusion and physical structure welding fusion under the synergistic coupling action of temperature, pressure and moisture, and can also form a uniform and dense three-dimensional mesh sodium silicate weather-resistant protective layer film on the surface of the material, thereby realizing high-performance, functional self-gluing and reconstructing manufacturing of the bamboo body unit.

(2) The method for manufacturing highly flame-retardant and highly waterproof bamboo body glued recombinant materials of the present invention adopts the synergistic treatment of "alkali solution pretreatment + sodium silicate impregnation", which can significantly improve the water resistance, flame retardancy, smoke suppression and weather resistance of the material. On the one hand, the alkali solution treatment can selectively depolymerize bamboo hemicellulose and a small part of lignin, and the generated highly active small molecules are free to undergo chemical condensation reaction based on the bamboo body material to achieve condensation cross-linking of the body material; secondly, the alkali solution selectively degrades the hemicellulose and part of the lignin of the wood particle unit, promotes the formation of multi-level pore structure of the cell wall, effectively increases the micro-nano porosity of the bamboo cell wall, and greatly increases the specific surface area and permeability of the wood particle unit, which can not only provide a smooth channel for subsequent impregnation treatment, but also optimize the basic conditions required for the welding and fusion of multi-scale physical structures in the subsequent body self-gluing formation process. On the other hand, the alkali solution pretreatment effectively increases the drug loading of sodium silicate in the cell wall cavity of bamboo, and the sodium silicate system uses the thermal conditions of molding to form a strong and dense protective film, which has extremely strong sealing properties and can effectively prevent the intrusion of liquids and significantly improve the waterproof and weather resistance, thereby effectively extending the service life of the product. When this protective layer encounters heat and fire, it will cause sodium silicate to form an inorganic silicon slag thermal barrier on the surface of the product, which can effectively block part of the heat transfer; furthermore, sodium silicate hydrolysis can form polysilicic acid, and the inorganic film produced will also form a barrier on the surface of the material, which can effectively prevent the convection of combustible gases, and then effectively inhibit the spread of flames, so the flame retardant and smoke suppression effect of the product can be increased by more than 80%. From the above content, it can be seen that the alkali solution pretreatment and sodium silicate impregnation treatment have a significant enhancement and coupling effect on the self-bonding functionalization of the bamboo body.

(3) Compared with the existing high-performance bamboo reconstructed bamboo manufacturing technology, since the present invention does not involve the addition of adhesives, while realizing the self-adhesive forming manufacturing of the functionalized bamboo body, the generation of organic volatile substances such as aldehydes and free phenols is avoided from the source, solving the safety risks of the human living environment due to the release of toxic and harmful substances in bamboo reconstructed materials, and expanding the application areas of bamboo reconstructed materials in indoor, car and harsh environments. Compared with the traditional glue-free forming manufacturing technology, the mechanical and weather resistance indicators of the products of the present invention far exceed those of traditional glue-free bonding products, breaking through the technical bottleneck that the traditional glue-free forming technology cannot achieve high-performance manufacturing of products.

(4) The highly flame-retardant and highly waterproof bamboo body glued reconstructed material product of the present invention has a forming strength exceeding 100MPa, a 24h room temperature water absorption thickness expansion rate of less than 1%, a flame-retardant and smoke-suppressing performance reaching the flame-retardant grade ( _B1 grade) and zero aldehyde and zero phenol release. It has the characteristics of high mechanical strength, water resistance, fire resistance and corrosion resistance, and is green, environmentally friendly and pollution-free. It can meet the requirements of high-strength load-bearing uses in harsh environments, and effectively solve the problem of excessive release of toxic and harmful substances in products faced by bamboo artificial board processing. On the other hand, the present invention uses bamboo processing residues as raw materials. While achieving the goal of high-strength and functionalized manufacturing of bamboo reconstructed materials, it also realizes the full biomass utilization of bamboo resources (up to 100%), breaking through the technical bottleneck of the difficulty in improving the utilization rate of bamboo resources.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a process flow chart of the production of bamboo body self-gluing reconstructed materials in Examples 1 and 2 of the present invention.

Detailed ways

The present invention will be described in further detail below. Unless otherwise specified, the instruments or materials used in the present invention are commercially available.

Embodiment 1:

A method for manufacturing a highly flame-retardant and highly waterproof bamboo body self-gluing reconstructed material of this embodiment comprises the following steps:

(1) Preparation of bamboo raw materials: Take the processing residues produced during the debonding and crushing process of fresh bamboo strips, remove metal foreign matter, and then use a crusher to coarsely grind the shavings. Then use a single-channel rotary drum dryer to dry for 10 min at a drying temperature of 105 °C and a rotation speed of 30 r/min to obtain the dried shavings units.

(2) Microwave-assisted treatment: Weigh the target sample amount of wood particle units, add a benzene-alcohol mixture (benzene and ethanol volume ratio is 2:1) at a material-liquid ratio of 1:30, and treat the mixture for 60 min under a microwave radiation intensity of 80 W to obtain the wood particle units after microwave treatment.

(3) Benzene-alcohol extraction of raw materials: The microwave-treated wood shavings units and the benzene-alcohol mixture were extracted in a water bath for 1.5 hours, and the wood shavings units were rinsed and filtered with alcohol and deionized water in turn to obtain the extracted wood shavings units.

(4) Alkali solution pretreatment: The extracted wood chip units are placed in a 10 wt% sodium hydroxide solution at a material-liquid ratio of 1:5, and treated at a temperature of 160°C for 0.5 h before being taken out to obtain wood chip units pretreated with alkali solution.

(5) Vacuum drying: Place the alkali pretreated wood shavings in a vacuum dryer and dry them at 100°C until the moisture content reaches 6%, then take them out for use.

(6) Sodium silicate impregnation loading: The dried pretreated wood chip units were placed in a 20 wt% sodium silicate aqueous solution, and then completely immersed at 60 °C for 2 h before being taken out to obtain the impregnated wood chip units.

(7) Drying balance treatment: Place the impregnated wood shavings unit in a single-channel rotary drum dryer until the target moisture content is adjusted to 6% and set aside.

(8) Loading raw materials into the mold: Before loading, apply a thin layer of liquid paraffin on the inner wall of the cavity and the working surface of the die punch to form an extremely thin lubricating film, otherwise it will affect the surface quality and forming effect of the slab. Put the shavings units into the mold cavity in batches and distribute them evenly in the cavity; be careful and apply even force during the powder feeding process to ensure that the filling effect is uniform and smooth.

(9) One-step compression molding: The blank, the mold and the backing plate are sent into a hot press for uniaxial bidirectional compression molding. The compression molding process used is: compression temperature of 180°C, compression pressure of 20 MPa, and holding time of 40 min.

(10) Slab cooling and demolding: After the pressing process reaches the heat preservation and pressure holding time, the slab should be cooled to below 60°C along with the mold by natural cooling. Then, a vibration force of a certain frequency is evenly applied to the pressure surface of the upper die to ensure that the formed slab is completely ejected from the lower outlet of the cavity to obtain a main body self-glued bamboo recombinant material slab.

The actual density of the bamboo main body self-gluing reconstructed material produced in this embodiment is 1.40 g/ ^cm3 , the static bending strength is 105MPa, the bending elastic modulus is 9000MPa, the 24h water absorption thickness expansion rate is 0.92%, and the flame retardant and smoke suppression performance reaches the flame retardant grade (B1 grade); in addition, no adhesive substances are added in the production process, and the product realizes the zero-aldehyde and zero-phenol manufacturing of bamboo reconstructed materials, which can meet the demand for high-strength load-bearing materials indoors, in vehicles and under harsh conditions.

Embodiment 2:

A method for manufacturing a highly flame-retardant and highly waterproof bamboo body self-gluing reconstructed material of this embodiment comprises the following steps:

(1) Preparation of bamboo raw materials: The residues produced by crushing fresh bamboo strips were removed by metal detector and then coarsely ground by crusher. The residues were then dried for 8 min in a single-channel rotary drum dryer at a drying temperature of 100 °C and a rotation speed of 40 r/min to obtain dried wood shavings.

(2) Microwave-assisted treatment: The wood chip units and benzene-alcohol solution (benzene and ethanol in a volume ratio of 2:1) were mixed at a material-liquid ratio of 1:50, and the mixture was treated for 30 min under a microwave radiation intensity of 100 W to obtain wood chip units after microwave-assisted treatment.

(3) Extraction of raw materials with benzene alcohol: extract the microwave-treated wood shavings unit and benzene alcohol mixture in a water bath for 1.5 hours, and rinse and filter the wood shavings unit with alcohol and deionized water in turn to obtain the extracted wood shavings unit.

(4) Alkali solution pretreatment: The extracted wood chip units are placed in a 20 wt% sodium hydroxide solution at a material-liquid ratio of 1:8, and treated at a temperature of 140°C for 1 hour before being taken out to obtain the wood chip units pretreated with alkali solution.

(5) Vacuum drying treatment: Place the alkali pre-treated wood shavings in a vacuum dryer and dry them at 80°C until the moisture content reaches 8%, then take them out for use.

(6) Sodium silicate impregnation loading: The dried pretreated wood chips were placed in a 30 wt% sodium silicate aqueous solution, and then treated by the breath impregnation method at a temperature of 50 °C for 1 h. The impregnated wood chip units were obtained.

When the particle size is large, the breathing impregnation method is used for the impregnation treatment, which uses the effect of negative pressure to compress the cell cavity and pores inside the bamboo. When the negative pressure is converted into positive pressure, the cell cavity and pores are completely opened to form a smooth channel to accelerate the invasion of the impregnant, which can significantly increase the drug loading and impregnation efficiency.

(7) Drying balance treatment: Place the impregnated wood shavings unit in a single-channel rotary drum dryer until the target moisture content is adjusted to about 12% and set aside.

(8) Loading raw materials into the mold: Before loading, apply a thin layer of liquid paraffin on the inner wall of the cavity and the working surface of the die punch to form an extremely thin lubricating film, otherwise it will affect the surface quality and forming effect of the slab. Put the shavings units into the mold cavity in batches and distribute them evenly in the cavity; be careful and apply even force during the powder feeding process to ensure that the filling effect is uniform and smooth.

(9) One-step compression molding: The blank, the mold and the backing plate are sent into a hot press for uniaxial bidirectional compression molding. The compression molding process used is: compression temperature of 200°C, compression pressure of 40 MPa, and holding time of 60 min.

(10) Slab cooling and demolding: After the pressing process reaches the heat preservation and pressure holding time, the slab should be cooled to below 60°C along with the mold by natural cooling. Then, a vibration force of a certain frequency is evenly applied to the pressure surface of the upper die to ensure that the formed slab is completely ejected from the lower outlet of the cavity to obtain a main body self-glued bamboo recombinant material slab.

The actual density of the bamboo body self-gluing reconstructed material produced in this embodiment is 1.46 g/cm ³ , the static bending strength is 120 MPa, the bending elastic modulus is 10000 MPa, the 24h water absorption thickness expansion rate is 0.66%, and the flame retardant and smoke suppression performance reaches the flame retardant grade (B1 grade); in addition, no adhesive substances are added in the production process, and the product realizes the zero-aldehyde and zero-phenol manufacturing of bamboo reconstructed materials, which can meet the demand for high-strength load-bearing materials indoors, in vehicles and under harsh conditions.

Comparative Example 1:

A method for manufacturing a bamboo body self-glued reconstructed bamboo of this comparative example is basically the same as the method for manufacturing in Example 1, except that the alkali solution pretreatment in step (4) is not performed. That is, the wood shavings are subjected to the benzene alcohol extraction treatment in step (3), the drying treatment in step (5), and then the sodium silicate impregnation loading in step (6), and finally the thermoforming treatment is completed under high temperature and high pressure conditions.

Comparative Example 2:

A method for manufacturing a bamboo body self-glued reconstructed bamboo of this comparative example is basically the same as the method for manufacturing in Example 1, except that the sodium silicate impregnation treatment in step (6) is not performed. That is, after the wood shavings are pre-treated with alkali solution in step (4), vacuum dried in step (5), and dried and balanced in step (7), they are directly subjected to the thermoforming treatment under high temperature and high pressure conditions.

Comparative Example 3:

A method for manufacturing the self-glued reconstructed bamboo of the bamboo body of this comparative example is basically the same as the manufacturing method of Example 2, except that the set molding temperature is different, and the molding temperature is 130° C. That is, after the wood shaving unit is prepared, the thermoforming treatment is completed under the condition of a molding temperature of 130° C.

Table 1 Performance test table of bamboo body self-gluing reconstructed bamboo prepared in various embodiments and comparative examples

As can be seen from Table 1, compared with Example 1, Comparative Example 1 does not implement the alkali solution pretreatment step, that is, the wood chip units are directly dried and balanced before being directly filled and hot-formed. The high-polysaccharide substances rich in the wood chip units cannot be depolymerized into monosaccharides, furfurals and other small molecular substances with adhesive effects under the action of alkali solution, and naturally cannot better promote the self-adhesive effect of the wood chip units. Secondly, the wood chip units that have not been pretreated with alkali solution cannot form a micro-nano pore structure on the surface of the bamboo fiber, and cannot increase the specific surface area of the wood chip units, which reduces the sodium silicate drug loading and self-adhesive physical welding fusion effect, and thus the product The water-resistant protective film layer formation and the body self-adhesive effect are also poor.

As can be seen from Table 1, compared with Example 1, Comparative Example 2 does not implement the sodium silicate impregnation step. Since the sodium silicate system will use the thermal conditions of compression molding to form a strong and dense protective film, it has extremely strong sealing and thermal stability, and can significantly improve waterproofness, fire resistance and weather resistance. Therefore, the water resistance and flame retardant and smoke suppression properties of Comparative Example 2 are far inferior to those of Example 1.

As can be seen from Table 1, the only difference between Comparative Example 3 and Example 2 is the compression molding temperature, which are 130°C and 200°C respectively. This is because the sodium silicate system will undergo a continuous temperature-triggered condensation reaction only under suitable high temperature conditions, which reduces the number of small silicate ions in the structure and increases the number of two-dimensional and three-dimensional large silicate ions, resulting in less dehydration produced by the polymerization reaction, so that an extremely dense protective film layer can be formed on the surface of the product; on the contrary, if the temperature is too low, the system is not completely dehydrated, the polymerization degree of the silicate anions is small, and more water is produced during the curing process, resulting in a loose film with many pores, which directly affects the weather resistance of the product.

Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make many possible changes and modifications to the technical solution of the present invention by using the technical contents disclosed above without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the scope of protection of the technical solution of the present invention.

Claims (10)

1. A manufacturing method of a high-flame-retardance high-waterproof bamboo self-gluing recombinant material is characterized by comprising the following steps of: the method comprises the following steps:

S1, performing benzene alcohol extraction treatment on dried bamboo shavings, and cleaning to obtain an extracted wood shaving unit;

S2, performing alkali liquor pretreatment on the extracted wood shaving units to obtain pretreated wood shaving units;

s3, placing the pretreated wood shaving units after drying and balancing treatment in a sodium silicate aqueous solution for dipping treatment to obtain dipped wood shaving units;

S4, carrying out drying balance treatment on the impregnated wood shaving units, then filling the wood shaving units into a die, carrying out compression molding treatment under the conditions of the temperature of 150-200 ℃ and the pressure of 10-45 MPa, cooling and demoulding to obtain the self-glued recombinant material of the bamboo body.

2. The manufacturing method according to claim 1, characterized in that: in the step S1, the dried bamboo shavings comprise the following preparation steps: and (3) preparing bamboo wood shavings from the bamboo raw materials, and drying to an air-drying state to obtain the dried bamboo shavings.

3. The manufacturing method according to claim 2, characterized in that: in the step S1, the bamboo material is one or more of bamboo green, bamboo yellow, bamboo pulp or bamboo processing residues.

4. The manufacturing method according to claim 1, characterized in that: in step S1, the benzene alcohol extraction treatment includes the following steps: and mixing the dried bamboo shavings with the benzyl alcohol mixed solution, then placing the mixture under the condition that the microwave radiation intensity is 80-100W, treating for 30-60 min, and then extracting the mixture for 1-2 hours under the condition of water bath.

5. The manufacturing method according to claim 4, wherein: in the step S1, the ratio of the dried bamboo shavings to the benzyl alcohol mixed solution is 1:20-50.

6. The method according to any one of claims 1 to 5, wherein in step S2, the lye pretreatment comprises the steps of: and (3) placing the extracted wood shaving units in an alkaline solution with the concentration of 5-20wt%, and performing chemical pretreatment for 0.5-1 h at the temperature of 140-160 ℃ to obtain pretreated wood shaving units.

7. The method according to claim 6, wherein in the step S2, the ratio of the wood shaving unit to the alkaline solution is 1:5-10.

8. The manufacturing method according to any one of claims 1 to 5, characterized in that: in the step S3, the dipping treatment includes the steps of: and (3) placing the dried pretreated wood shaving unit in 5-30wt% sodium silicate aqueous solution, keeping the temperature at 40-60 ℃ for 1-2 hours, and taking out to obtain the impregnated wood shaving unit.

9. The manufacturing method according to any one of claims 1 to 5, characterized in that: in the step S4, the pressure maintaining time of the compression molding treatment is 20-70 min; and curing and machining treatment are further included after demolding.

10. The utility model provides a high fire-retardant high waterproof bamboo timber body is from veneer reorganization material which characterized in that: the bamboo body self-glued recombinant material is prepared by the manufacturing method according to any one of claims 1 to 9.