Preparation method of flame-retardant antibacterial bamboo-wood composite shaving board

Abstract

The invention provides an antibacterial flame-retardant bamboo-wood composite shaving board and a preparation method thereof. According to the bamboo-wood composite shaving board manufactured through the method, the mechanical property can be kept, and meanwhile the good flame retardant effect is achieved. The composite flame retardant disclosed by the invention is simple in preparation method, cheap and easily available in raw materials, capable of saving cost and relatively high in industrial production value. The bamboo-wood composite shaving board does not need a layered preparation process, is simple in overall process condition, and is environment-friendly and safe.

Description

Technical Field

[0001] The invention belongs to the field of particleboards, and in particular relates to a method for preparing a flame-retardant and antibacterial bamboo-wood composite particleboard. Background Art

[0002] In order to solve the problem of shortage of domestic oriented strand board raw materials, promote the performance upgrade and function improvement of oriented strand board, and expand its application range, the development of high-strength oriented strand board based on diversified raw materials should be strengthened. Bamboo has high density and high strength. Adding it to wood oriented strand board to prepare bamboo-wood composite oriented strand board can give full play to the advantages of light weight of wood and high strength of bamboo, prepare high-performance composite materials, improve the physical and mechanical properties of existing wood oriented strand board, expand its application range, and increase product value.

[0003] Semple et al. (European Journal of Wood and Wood Products, 2015, 73(4):527-536) prepared oriented strand board by mixing poplar shavings and bamboo shavings and found that the addition of bamboo can increase the strength of oriented strand board and improve the dimensional stability of the board. Cheng et al. (Key Engineering Materials, 2012(517):87-95), Wang Siqun and Hua Yukun (Wood Industry, 1991(3): 6-10) analyzed the mechanical properties of bamboo-wood composite oriented strand board. The studies showed that increasing the bamboo shaving ratio in the board can increase the strength of the board, but too high a bamboo ratio will reduce the strength-to-weight ratio of the board. Sun Yuhui et al. (China Wood-Based Panels, 2022, 29(12): 7-10) found that the addition of bamboo significantly increased the static bending strength of the board, and the contribution rate of bamboo increased with the increase of density, but the addition of bamboo had little effect on the elastic modulus, compressive strength and shear strength as a whole. Microscopic observations showed that the adhesive can penetrate into the bamboo cells well, forming a good bonding interface. Han Shuwei et al. used bamboo shavings and recycled shavings to make composite particleboard, and preliminarily explored its production process, providing a useful reference for the recycling of waste particleboard.

[0004] Bamboo contains starch, sugar, protein and other nutrients. Once the water, temperature and humidity are suitable, bamboo becomes a culture medium for mold and discoloration bacteria, causing defects such as mold or discoloration on the surface of bamboo, reducing its use value and service life. In addition, moldy or rotten bamboo products will pollute the living environment and threaten human health. Studies have shown that when the hyphae spores of moldy products float in the air, they may cause people to suffer from allergies, asthma and other respiratory infections.

[0005] In 2009, Li Liang et al. (China Wood-Based Panels, 2009, 16(07): 16-18) investigated the antibacterial and antifungal properties of alkyl ammonium compounds (AAC) and boric acid on bamboo particleboard. The results showed that the antifungal properties of alkyl ammonium antifungal agents were better than those of boric acid; the higher the concentration of antifungal agents, the stronger the antifungal properties, and the efficacy against mold gradually decreased with time; surface treatment and internal treatment had no effect on the antifungal ability of bamboo particleboard. In 2014, Jin Juwan (Forest Products Industry, 2014, 41(02):47-49) used bamboo as raw material, urea-formaldehyde resin glue, phenolic resin glue and isocyanate glue as adhesives, and zinc borate as antifungal agent to produce bamboo oriented strand board, and explored its antifungal properties and physical and mechanical properties. The results show that the physical and mechanical properties of the three types of mildew-resistant bamboo oriented strand boards meet the quality requirements of LY / T 1580-2010 "Oriented Strand Board"; when the addition amount of zinc borate is the same, the mildew-resistant properties of mildew-resistant bamboo oriented strand boards prepared by phenolic resin glue and isocyanate glue are better than those prepared by urea-formaldehyde resin glue. Huaxu Z (Polymers, 2020, 13(1):98) studied the effects of different citric acid contents on the physical and mechanical properties and antibacterial properties of particleboards. The results show that the performance of particleboards increases with the increase of citric acid content. At present, domestic and foreign researchers have also studied the antibacterial and mildew-resistant effects of bamboo and wood in terms of organic iodides, inorganic nanomaterials and natural extracts.

[0006] Bamboo and wood are both flammable. Many fires are related to bamboo and wood, which pose a great threat to people's lives and property. Therefore, the flame retardant research of bamboo-wood composite materials has important practical significance. At present, there are four main methods for the flame retardant process of particleboard. One is the veneer impregnation method, the second is to spray fireproof materials on the surface of the finished slab, the third is to add flame retardants during the preparation of the slab, and the fourth is to flame retard the adhesive used. No matter which method is used, the board is treated uniformly from the surface to the inside. The most commonly used inorganic flame retardant for particleboard is a compound containing P, N, B, Al and halogen, which can be roughly divided into phosphorus-nitrogen system based on ammonium phosphate, boron system based on boride, halogen system containing halogen compounds, and metal oxides or hydroxides containing Mg, Al, etc. Inorganic flame retardants have the advantages of being environmentally friendly, easy to obtain, low price, and convenient to apply, but they also have the disadvantages of high water absorption, greatly reducing the bonding strength, and easy to seep out and deviate. The mainstream of organic flame retardants is still a multi-component complex containing phosphorus, boron and nitrogen elements. Phosphorus or halogen participates in the reaction during polymerization or polycondensation and is combined into the main chain or side chain of the polymer. Its advantages are high anti-loss and little effect on the mechanical properties of the board; its disadvantages are that it produces a lot of smoke and gas during combustion, and its flame retardant performance is unstable, which will cause pollution.

[0007] Li Liang et al. (Inner Mongolia Forestry Survey and Design, 2008, 31 (6): 96-97) reported that the board has good physical and mechanical properties when phosphorus-nitrogen and boron flame retardants are mixed in a ratio of 1:1. Mao Wei (Study on the preparation process and performance of large-scale particleboard with layered flame retardant, master's degree thesis of Nanjing Forestry University) reported that different flame retardants are applied in different doses in layers according to the "surface-core-surface" hot pressing method, so that different flame retardants will not contact each other, which will not cause chemical conflicts between flame retardants, and can also be distributed and applied in large pieces of flame-retardant particleboard according to the characteristics of different flame retardants themselves. However, the effect of this compound flame retardant is difficult to predict. It still requires a lot of work to choose which flame retardant to compound and how to choose the appropriate dosage.

[0008] In summary, although there have been literature reports on the antibacterial and flame retardant modification of bamboo-wood composite boards, the existing bamboo-wood composite boards are difficult to achieve good antibacterial effects and good flame retardant properties while maintaining the high mechanical properties of bamboo boards. Therefore, it is of great significance to develop new antibacterial and flame retardant bamboo-wood composite boards. Summary of the invention

[0009] The purpose of the present invention is to provide an antibacterial flame retardant bamboo-wood composite particleboard and a preparation method thereof. The bamboo-wood composite particleboard prepared by the method of the present invention has good flame retardant and antibacterial properties, and the mechanical properties of the particleboard itself are less affected.

[0010] The first aspect of the present invention provides a method for preparing an antibacterial flame-retardant bamboo-wood composite particleboard, which comprises the following steps: 1) respectively putting bamboo shavings and wood shavings into the antibacterial finishing liquid, soaking them, then taking out the bamboo shavings and wood shavings, drying them and setting them aside; 2) applying a flame retardant to bamboo shavings and wood shavings; 3) Adjust the moisture content of wood chips; 4) Gluing bamboo shavings and wood shavings; 5) Press the boards to obtain bamboo-wood composite boards; The flame retardant is composed of diethyl aluminum hypophosphite, magnesium hydroxide and zinc borate, wherein the weight ratio of diethyl aluminum hypophosphite, magnesium hydroxide and zinc borate is (2-5): (2-5):1.

[0011] Preferably, the antibacterial finishing liquid in step 1) is a solution containing IPBC (iodopropane orthocarbamate), and the soaking time is 36-72 hours, more preferably 48 hours.

[0012] Preferably, the amount of the flame retardant applied in step 2) is 1%-5% of the weight of the bamboo shavings or wood shavings, calculated on a relative basis, more preferably 3%.

[0013] Preferably, the flame retardant is applied in step 2) by preparing the flame retardant into a 5-20% by weight solution and then spraying it onto the bamboo shavings and wood shavings; more preferably, the flame retardant is prepared into a 10-15% by weight solution and then spraying it onto the bamboo shavings and wood shavings; Preferably, in step 3), the moisture content of the bamboo shavings and the wood shavings is adjusted to 5%-20%, more preferably 10%-15%.

[0014] Preferably, step 4) uses a bamboo-to-wood ratio of 1:0.5-2 for gluing, more preferably 1:1; wherein the amount of gluing is 4%-8% of the mass of the absolute dry wood shavings, more preferably 6%; and the adhesive used for gluing is selected from urea-formaldehyde resin glue and melamine glue.

[0015] Another aspect of the present invention provides an antibacterial and flame-retardant bamboo-wood composite particleboard, which is prepared by the above method.

[0016] In bamboo-wood composite particleboard, with the increase of flame retardant addition, the mechanical properties of bamboo-wood composite board, such as static bending strength, elastic modulus, and internal bonding strength, all show a downward trend. The reason is that the presence of flame retardant hinders the adhesion between adhesive and particle interface. After adding flame retardant, the water absorption thickness expansion rate of bamboo-wood composite board increases significantly, and it shows an upward trend with the increase of flame retardant addition. Therefore, how to achieve a balance between flame retardant performance and mechanical properties is a difficulty in this field.

[0017] Currently, there is no literature reporting that mixing diethyl aluminum hypophosphite, magnesium hydroxide, and zinc borate as a composite flame retardant can achieve a good flame retardant effect while maintaining mechanical properties.

[0018] Beneficial effects: 1) The bamboo-wood composite particleboard of the present invention can achieve a good flame retardant effect while maintaining mechanical properties.

[0019] 2) The composite flame retardant of the present invention has a simple preparation method, and the raw materials are cheap and readily available, which can save costs and has high industrial production value.

[0020] 3) The bamboo-wood composite particleboard of the present invention does not require a layered preparation process, the overall process conditions are simple, and it is environmentally friendly and safe. DETAILED DESCRIPTION

[0021] The following examples are provided to illustrate the present invention in detail. The following examples are provided to better illustrate the present invention and are not intended to limit the scope of the present invention. The materials, reagents, etc. used in the following examples, unless otherwise specified, can be obtained from commercial sources.

[0022] Example 1 Preparation of bamboo-wood composite particleboard 1) respectively put bamboo shavings (water content 9%-10%) and wood shavings (water content 9%-10%) into an ethanol solution of IPBC (iodopropane orthocarbamate) (concentration 150g / L), stir and mix evenly, soak for 48 hours, then take out the bamboo shavings and wood shavings, dry them, and the moisture content of the dried shavings is 8%-10%, and set aside; 2) Prepare a 15% by weight solution of the flame retardant and spray it quantitatively at 3% of the particleboard mass (absolute weight); 3) Adjust the moisture content of the wood shavings to about 15%; 4) Mechanical glue mixing is used to apply glue at a bamboo-to-wood ratio of 1:1; the amount of glue applied is 6% of the mass of the absolutely dry wood shavings; the adhesive used for gluing is selected from urea-formaldehyde resin glue.

[0023] 5) The continuous flat press is used for hot pressing. The design density of the bamboo-wood composite board is 0.85g / cm 3 ; 6) Sawed specimens with a size of 200 mm × 200 mm and a thickness of 10 mm; The flame retardant is composed of diethyl aluminum hypophosphite, magnesium hydroxide and zinc borate, wherein the weight ratio of diethyl aluminum hypophosphite, magnesium hydroxide and zinc borate is 4:4:1.

[0024] Example 2 Referring to the method of Example 1, the only difference is that the flame retardant consists of diethylaluminum hypophosphite, magnesium hydroxide and zinc borate, wherein the weight ratio of diethylaluminum hypophosphite, magnesium hydroxide and zinc borate is 3:5:1.

[0025] Example 3 Referring to the method of Example 1, the only difference is that the flame retardant consists of diethylaluminum hypophosphite, magnesium hydroxide and zinc borate, wherein the weight ratio of diethylaluminum hypophosphite, magnesium hydroxide and zinc borate is 3:3:1.

[0026] Example 4 Referring to the method of Example 1, the only difference is that the flame retardant consists of diethylaluminum hypophosphite, magnesium hydroxide and zinc borate, wherein the weight ratio of diethylaluminum hypophosphite, magnesium hydroxide and zinc borate is 5:3:1.

[0027] Example 5 Referring to the method of Example 1, the only difference is that the flame retardant consists of diethylaluminum hypophosphite, magnesium hydroxide and zinc borate, wherein the weight ratio of diethylaluminum hypophosphite, magnesium hydroxide and zinc borate is 3:2:1.

[0028] Example 6 Referring to the method of Example 1, the only difference is that the flame retardant consists of diethylaluminum hypophosphite, magnesium hydroxide and zinc borate, wherein the weight ratio of diethylaluminum hypophosphite, magnesium hydroxide and zinc borate is 1:1:1.

[0029] Comparative Example 1 Referring to the method of Example 1, the only difference is that the flame retardant consists of diethylaluminum hypophosphite and magnesium hydroxide, wherein the weight ratio of diethylaluminum hypophosphite to magnesium hydroxide is 1:1.

[0030] Comparative Example 2 Referring to the method of Example 1, the only difference is that the flame retardant consists of diethyl aluminum hypophosphite and zinc borate, wherein the weight ratio of diethyl aluminum hypophosphite to zinc borate is 1:1.

[0031] Comparative Example 3 Referring to the method of Example 1, the only difference is that the flame retardant consists of magnesium hydroxide and zinc borate, wherein the weight ratio of magnesium hydroxide to zinc borate is 4:1.

[0032] Comparison example The method of Example 1 is referred to, except that no flame retardant is added.

[0033] Example 7 Mechanical properties test Referring to the "Test Methods for Physical and Chemical Properties of Artificial Boards and Faced Artificial Boards" GB / T 17657-2013, the 24h water absorption thickness expansion rate (24h TS), static bending strength (MOR) and elastic modulus (MOE) of the test board were tested. From the two boards prepared repeatedly, 4 MOR\MOE specimens and 4 24h TS\IB specimens were taken, and the results were averaged and the standard deviation was calculated. The results are as follows:

[0034] It can be seen from the above table that the ternary composite flame retardant system of the present invention has good mechanical properties, and is well maintained in terms of 24h water absorption thickness expansion rate (24h TS), static bending strength (MOR) and elastic modulus (MOE).

[0035] Example 8 Oxygen Index Test According to the Chinese national standard GB / T2406.2-2009, an HC900-2 oxygen index meter was used. Nitrogen and oxygen were introduced into the combustion tube (75 mm in diameter, 400 mm in height) at a flow rate of 40 mm±10 mm / s, respectively, and the minimum oxygen volume percentage required to ignite and maintain continuous combustion of the sample was recorded. The bamboo-wood composite particleboard prepared in the above-mentioned embodiment, comparative example and control group was made into a long strip, that is, the sample for oxygen index test was obtained, and the size of each sample was 100 mm×10 mm×10 mm. The results are as follows:

Claims

1. A method for preparing an antibacterial flame-retardant bamboo-wood composite particleboard, comprising the following steps: 1) respectively putting bamboo shavings and wood shavings into the antibacterial finishing liquid, soaking them, then taking out the bamboo shavings and wood shavings, drying them and setting them aside; 2) applying a flame retardant to bamboo shavings and wood shavings; 3) Adjust the moisture content of wood chips; 4) Gluing bamboo shavings and wood shavings; 5) Press the boards to obtain bamboo-wood composite boards; The flame retardant is composed of diethyl aluminum hypophosphite, magnesium hydroxide and zinc borate, wherein the weight ratio of diethyl aluminum hypophosphite, magnesium hydroxide and zinc borate is (2-5): (2-5):

1.

2. The preparation method according to claim 1, wherein: In step 1), the antibacterial finishing liquid is a solution containing IPBC (iodopropane orthocarbamate), and the soaking time is 48 hours.

3. The preparation method according to claim 1, wherein: In step 2), the amount of the flame retardant applied is 1% to 5% of the weight of the bamboo shavings or wood shavings, calculated on a relative basis.

4. The preparation method according to claim 3, wherein: The amount of the flame retardant applied in step 2) is 3% of the weight of the bamboo shavings or wood shavings, calculated on a relative basis.

5. The preparation method according to any one of claims 1 to 4, wherein: In step 2), the flame retardant is applied by preparing a 5-20% by weight solution of the flame retardant and then spraying it onto the bamboo shavings and wood shavings.

6. The preparation method according to any one of claims 1 to 4, wherein: In step 3), the moisture content of the bamboo shavings and the wood shavings is adjusted to 10%-15%.

7. The preparation method according to any one of claims 1 to 4, wherein: Step 4) applying glue at a bamboo-to-wood ratio of 1:0.5-2; wherein the amount of glue applied is 4%-8% of the mass of the absolutely dry wood shavings; and the adhesive used for gluing is selected from urea-formaldehyde resin glue and melamine glue.

8. An antiseptic and antibacterial bamboo-wood composite particleboard, prepared by the method according to any one of claims 1 to 7.

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