Bamboo-wood composite modifier and application thereof

Abstract

This invention relates to a bamboo-wood composite modifier and its application. The modifier is prepared by adding 1%-10% by mass of enzymatically hydrolyzed lignin to 1,4-dioxane as a solvent. Bamboo mats are immersed in a 1,4-dioxane solution containing completely dissolved enzymatically hydrolyzed lignin under normal pressure for modification. The modified bamboo mats are then impregnated with veneer, alternately stacked, and hot-pressed to prepare a bamboo-wood composite container floor. The excellent mechanical and corrosion-resistant properties of enzymatically hydrolyzed lignin are utilized to fill the bamboo mats, thereby improving the mechanical and biological durability of the bamboo-wood composite container floor.

Description

Technical Field

[0001] This invention relates to the field of wood processing technology, specifically to a bamboo-wood composite modifier and how to use it to modify bamboo curtains, as well as how to use the modified bamboo curtains to make container flooring. Background Technology

[0002] Studies have shown that the better the mechanical properties of the surface material, the greater its contribution to the overall mechanical properties of the plywood. Many studies first subject the surface wood veneer of the container floor to high-pressure compression to obtain a high-performance container floor surface material, which is then glued to the core layer to prepare a new type of bamboo-wood composite container floor. However, this method is prone to problems such as loose wood texture and significant performance defects. Excessive compression ratio can also lead to waste of raw materials, and this method has high production costs. Although patent application CN107972144A discloses a method for modifying wood based on alkali lignin composite heat treatment, including the following steps: 1) Immersing vacuum-treated wood in a 1,4-dioxane solution of alkali lignin, adjusting the pressure to 0.2~0.8MPa, and holding the pressure for 50~90min; 2) Taking out the soaked wood, drying it, and then placing it at 120~200℃ for heat treatment for 1.5~4h to obtain modified wood. This patent application describes a low-cost, simple, non-toxic, and long-lasting wood modification method. It combines this method with a heat treatment process to produce modified wood that is highly waterproof, large-sized, and stable in performance. This effectively overcomes the defects of fast-growing timber, such as cracking and deformation, increases the added value of the product, and solves the bottleneck problem in the application of fast-growing timber. However, the strong alkalinity of alkali lignin itself can affect the mechanical and biological durability properties of wood.

[0003] We used an enzymatic hydrolysis lignin solution to fill bamboo curtains with inexpensive enzymatic hydrolysis lignin through atmospheric pressure soaking modification method. We then used wood veneer and modified bamboo curtains to prepare bamboo-wood composite container flooring, thereby improving the mechanical and biological durability of the bamboo-wood composite container flooring. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method to improve the corrosion resistance and bonding strength of bamboo-wood composite container floor panels. This method uses industrially enzymatically hydrolyzed lignin obtained from wood materials as a natural green modifier. The lignin is filled into the gaps of bamboo curtains and cured through a simple atmospheric pressure soaking method. The modified bamboo curtains are then used to prepare bamboo-wood composite container floor panels, which significantly improves their biological durability and bonding strength.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A bamboo-wood composite modifier is prepared by adding 1,4-dioxane as a solvent and 1%-10% by mass of enzymatically hydrolyzed lignin. The bamboo and wood are modified by immersion under normal pressure, so that the enzymatically hydrolyzed lignin fills the gaps in the bamboo and wood.

[0007] Preferably, the enzymatically hydrolyzed lignin is dried enzymatically hydrolyzed lignin.

[0008] Preferably, the bamboo curtain is completely immersed in the bamboo-wood composite modifier under normal pressure for 20-30 hours.

[0009] Preferably, the bamboo curtain is completely immersed in the bamboo-wood composite modifier under normal pressure for 24 hours.

[0010] Preferably, the prepared bamboo-wood composite modifier needs to be ultrasonically cleaned for two hours and then stirred by a magnetic stirrer for 6-8 hours to fully dissolve the enzymatically hydrolyzed lignin in the solvent.

[0011] The method for modifying bamboo and wood using the aforementioned bamboo-wood composite modifier is as follows: the bamboo mat to be modified is laid flat in a well-ventilated modification tank, the prepared composite modifier is poured into the modification tank, and the bamboo mat is completely immersed in the composite modifier under normal pressure for modification.

[0012] The method for using the modified bamboo curtain described above to manufacture bamboo-wood composite container flooring includes the following steps:

[0013] (1) Take out the bamboo curtain after soaking it in the modified pool at normal pressure, clean the surface with ethanol, and then place it in a ventilated place to stand for 24 hours;

[0014] (2) The bamboo curtain treated in step (1) is immersed in phenolic resin for impregnation. After impregnation, the bamboo curtain is taken out and laid on Teflon cloth to air dry naturally until no more glue drips.

[0015] (3) The wood veneer and bamboo curtain are orthogonally assembled to prepare a bamboo-wood composite container floor with at least 3 layers;

[0016] (4) After the billet is assembled, the iron plate is placed on the surface of the composite plate for pre-pressing treatment;

[0017] (5) The bottom and surface of the pre-pressed bamboo and wood composite container bottom plate blank are covered with Teflon cloth and placed in a multi-layer hot press at room temperature for hot pressing treatment.

[0018] (6) After the hot pressing process is completed, set the pressure holding pressure and hold the pressure. After the temperature of the hot press drops to 20℃-40℃, take out the bottom plate of the bamboo-wood composite container.

[0019] Preferably, the pressure holding pressure is 1.0MPa-1.5MPa.

[0020] Preferably, the actual pressure of the hot pressing treatment is 2.6MPa-3.6MPa, the hot pressing temperature is 130-160℃, and the hot pressing time is 30-50min.

[0021] Preferably, the pre-compression treatment time is 5 min to 15 min.

[0022] Preferably, the impregnation time for the impregnation treatment is 2-10 minutes, and the impregnation amount is 250-350 g / m2.

[0023] Beneficial effects

[0024] The beneficial effects of this invention are that the bamboo-wood composite container floor modified by enzymatic hydrolysis and lignin soaking not only significantly improves biological durability and bonding strength, but also the modification method is simple and easy to operate.

[0025] Testing revealed that the bamboo-wood composite container floor prepared by modifying bamboo curtains with 1,4-dioxane solution of enzymatically hydrolyzed lignin showed a 27.17% increase in bonding strength and a 37.88% decrease in weight loss compared to the bamboo-wood composite container floor prepared by modifying bamboo curtains with 1,4-dioxane solution of alkali lignin. This indicates that the bamboo-wood composite container floor prepared by modifying bamboo curtains with 1,4-dioxane solution of enzymatically hydrolyzed lignin has significant and beneficial technical effects. Attached Figure Description

[0026] Figure 1 This is a comparison chart of adhesive strength.

[0027] Figure 2 This is a chart showing the weight loss rate. Detailed Implementation

[0028] To make the objectives and advantages of the present invention clearer, the present invention will be specifically described below in conjunction with embodiments.

[0029] This experiment used atmospheric pressure soaking to modify bamboo curtains.

[0030] In one specific embodiment, it includes the following step-by-step implementation:

[0031] (1) Preparation of composite modifier: Using 1-4 dioxane as solvent, add 1%-10% of enzymatic hydrolyzed lignin by mass fraction of solvent; the specific method is to dry the enzymatic hydrolyzed lignin and pour it into a beaker containing solvent, use an ultrasonic cleaner to sonicate for 2 hours, and then place the beaker on a magnetic stirrer to stir for 7 hours to ensure that the enzymatic hydrolyzed lignin can be fully dissolved in the solvent.

[0032] (2) Modification of bamboo curtains: The bamboo curtain sample to be modified is laid flat in an enamel pot, and the prepared solution is poured into it. The lignin is filled into the bamboo curtain by immersion under normal pressure, so that the bamboo curtain is completely submerged in the solution. Then it is placed in a fume hood.

[0033] Let it stand for 24 hours, and use a copper block to weigh it down to prevent it from floating and affecting the modification effect; then soak the bamboo mat under normal pressure for 24 hours.

[0034] After 24 hours, remove the product, clean the surface with ethanol, and then place it in a fume hood to stand for 24 hours.

[0035] (3) Preparation of bamboo-wood composite container floor: The modified bamboo curtain is placed in phenolic resin for about 8 minutes and the amount of resin is 300g / m2. After the resin is impregnated, the bamboo curtain is taken out and laid on Teflon cloth to air dry naturally until no more resin drips. Pine veneer and bamboo curtain are stacked alternately to form a 21-layer bamboo-wood composite container floor. After the floor is assembled, an iron plate is placed on the surface of the composite board for pre-pressing for about 10 minutes. Teflon cloth is laid on the bottom and surface of the pre-pressed bamboo-wood composite container floor blank. It is placed in a multi-layer hot press at room temperature. The hot pressing pressure on the board is 3MPa, the hot pressing temperature is 150℃, and the hot pressing time is 40 minutes. After the hot pressing is completed, the board is held under a holding pressure of 1.2MPa. After the press temperature drops to 25℃, the bamboo-wood composite container floor is taken out.

[0036] In the testing of adhesive strength, such as Figure 1 As shown, the bamboo-wood composite container floor prepared by modifying bamboo curtains with 1,4-dioxane solution of lignin through enzymatic hydrolysis was compared with the control material: the bamboo-wood composite container floor prepared by modifying bamboo curtains with 1,4-dioxane solution of alkali lignin was tested using a universal testing machine for its bonding strength. According to the mechanical property test requirements in GB / T19536 (2015), several longitudinal and transverse samples with a size of 150mm×50mm×5mm were cut from each plywood using a circular saw. The samples were placed on the testing machine, and their static bending strength and modulus of elasticity were measured according to the three-point bending performance test standard. According to the test method for physical and chemical properties of wood-based panels and decorative wood-based panels in GB / T 17657 (2013), several transverse and longitudinal samples with a size of 25mm×100mm were cut from the plywood, and grooves were made on the samples. The groove depth was about 2 / 3 of the thickness, and the groove spacing was 25mm. The samples were placed on a universal testing machine, clamped at both ends, and the tensile strength was measured after zeroing. The tensile curves of bamboo-wood composite boards prepared with different lignin modifications were compared. The results showed that the bonding strength of the base plate prepared with alkali lignin was only 21.38 MPa, while the bonding strength of the bamboo-wood composite container base plate prepared with enzymatically hydrolyzed lignin modification increased to 27.19 MPa, an increase of 27.17%.

[0037] In the detection of weight loss rate, such as Figure 2 As shown, the bamboo-wood composite container floor prepared by modifying bamboo curtains with 1,4-dioxane solution of lignin through enzymatic hydrolysis exhibits improved corrosion resistance compared to the control material: the bamboo-wood composite container floor prepared by modifying bamboo curtains with 1,4-dioxane solution of alkali lignin. The weight loss rate of the samples was tested according to the national standard GB / T13942.1 (2009). The results show that the weight loss rate of the bamboo-wood composite container floor modified with enzymatic hydrolysis was 5.1%, which is 37.88% lower than the 8.21% weight loss rate of the floor prepared with alkali lignin modification.

[0038] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. For those skilled in the art, after learning the contents described in the present invention, several equivalent changes and substitutions can be made without departing from the principle of the present invention. These equivalent changes and substitutions should also be considered to fall within the protection scope of the present invention.

Claims

1. A method for modifying bamboo and wood using a bamboo-wood composite modifier, characterized in that: Lay the bamboo mat to be modified flat in a well-ventilated modification tank, pour the prepared bamboo-wood composite modifier into the modification tank, and let the bamboo mat be completely immersed in the bamboo-wood composite modifier under normal pressure for modification, so that the enzymatic hydrolyzed lignin fills the gaps in the bamboo mat. The bamboo-wood composite modifier is prepared by adding 1%-10% enzymatically hydrolyzed lignin as a solvent, using 1,4-dioxane as the solvent.

2. A method for modifying bamboo and wood using a bamboo-wood composite modifier according to claim 1, characterized in that: The prepared bamboo-wood composite modifier needs to be ultrasonically cleaned for two hours and then stirred with a magnetic stirrer for 6-8 hours to fully dissolve the enzymatically hydrolyzed lignin in the solvent.

3. A method for modifying bamboo and wood using a bamboo-wood composite modifier according to claim 2, characterized in that: The bamboo curtain is completely immersed in the bamboo-wood composite modifier under normal pressure for 20-30 hours.

4. A method for modifying bamboo and wood using a bamboo-wood composite modifier according to claim 3, characterized in that: The bamboo curtain is completely immersed in the bamboo-wood composite modifier for 24 hours under normal pressure.

5. A method for manufacturing bamboo-wood composite container floor panels, characterized in that: Includes the following steps: (1) Take out the bamboo curtain modified by the method of bamboo and wood composite modifier according to any one of claims 1-4, clean the surface with ethanol, and then place it in a ventilated place to stand for 24 hours. (2) The bamboo curtain treated in step (1) is immersed in phenolic resin for impregnation. After impregnation, the bamboo curtain is taken out and laid on Teflon cloth to air dry naturally until no more glue drips. (3) The wood veneer and bamboo curtain are orthogonally assembled to prepare at least 3 layers of bamboo-wood composite container floor; (4) After the billet is assembled, the iron plate is placed on the surface of the composite plate for pre-pressing treatment; (5) The bottom and surface of the pre-pressed bamboo and wood composite container bottom plate blank are covered with Teflon cloth and placed in a multi-layer hot press at room temperature for hot pressing treatment. (6) After the hot pressing process is completed, set the pressure holding pressure and hold the pressure. After the temperature of the hot press drops to 20℃-40℃, take out the bottom plate of the bamboo-wood composite container.

6. A method for manufacturing a bamboo-wood composite container floor according to claim 5, characterized in that: The pressure holding pressure is 1.0MPa-1.5MPa.

7. A method for manufacturing a bamboo-wood composite container floor according to claim 6, characterized in that: The hot pressing pressure is 2.6MPa-3.6MPa, the hot pressing temperature is 130-160℃, and the hot pressing time is 30-50min.

8. A method for manufacturing a bamboo-wood composite container floor according to claim 7, characterized in that: The pre-compression treatment time is 5 min to 15 min.

9. A method for manufacturing a bamboo-wood composite container floor according to claim 8, characterized in that: The impregnation time is 2-10 minutes, and the impregnation amount is 250-350 g / m2.

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