Preparation method of ultrathin mildew-proof flame-retardant fiberboard

Abstract

The invention discloses a preparation method of an ultrathin mildew-proof flame-retardant fiberboard, and relates to the technical field of wood material preparation, and the preparation method comprises the following preparation steps: pretreatment of wood fibers; preparing a curing agent; preparing a flame retardant; then, urea-formaldehyde resin adhesive, a curing agent and a flame retardant are sequentially poured into the pretreated wood fibers, drying is conducted after uniform mixing, the mixture is poured into a hot press for hot press forming, and the fiberboard is obtained; and then the fiberboard is sequentially placed in clear water, chitosan, an AgNO3 solution and a NaBH solution to be soaked and washed, drying is conducted, and the ultrathin mildew-proof flame-retardant fiberboard is obtained. According to the invention, the wood fiber is soaked in laccase, and then treated calcium carbonate is added, so that the flame retardant effect of the wood fiber is improved; meanwhile, the melamine phosphate can promote decomposition of the magnesium-aluminum hydrotalcite, so that the decomposition temperature of the magnesium-aluminum hydrotalcite is reduced, and the acting temperature range of the flame retardant is expanded; and the fiberboard is subjected to multiple soaking mildew-proof treatment, so that the mildew-proof performance of the fiberboard is effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of wood material preparation, in particular to a method for preparing an ultra-thin mildew-proof and flame-retardant fiberboard. Background Art

[0002] As a new variety in the field of fiberboard, ultra-thin fiberboard expands and extends the use of high-density ultra-thin fiberboard, replacing most of the uses of cardboard that is more polluting and has high production costs, and has broad prospects.

[0003] The Chinese patent with publication number CN116728545A discloses an antibacterial flame-retardant ultra-thin fiberboard and its preparation method, which can obtain good antibacterial and flame-retardant properties, and can adapt to high-temperature hot pressing of ultra-thin fiberboard without affecting the curing process of the adhesive. The preparation method includes: adding NP-SP solution to urea-formaldehyde resin adhesive, adding NaOH aqueous solution to adjust the pH value after sufficient stirring to obtain antibacterial flame-retardant adhesive 1; continuing to add modified porphyrin-type cobalt antibacterial agent N-Co to antibacterial flame-retardant adhesive 1, blending evenly to obtain antibacterial flame-retardant adhesive 2; blending wood fiber and antibacterial flame-retardant adhesive 2 evenly in a glue mixer, drying the wood fiber after mixing, and obtaining a paving material with a moisture content of 6.0-6.5%; paving the paving material into a continuous slab strip, setting the target board thickness to 1.2mm and the fiberboard density to 800Kg / m 3 , and the slab is sent to a hot press for hot pressing. However, the flame retardant effect of the fiberboard prepared above is limited, and the flame retardant performance needs to be further improved. In addition, its mildew resistance is poor, which limits its scope of use. Therefore, the present invention provides a method for preparing an ultra-thin mildew-proof flame-retardant fiberboard to solve the above problems. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a method for preparing an ultra-thin mildew-proof and flame-retardant fiberboard, which solves the problems mentioned in the above background technology.

[0005] To achieve the above objectives, the present invention is implemented by the following technical scheme: A method for preparing an ultra-thin mildew-proof and flame-retardant fiberboard, comprising the following preparation steps: Step I: pretreatment of wood fiber: pour laccase into 200 mL of citric acid-disodium hydrogen phosphate buffer, and after heating, immerse 70 g of wood fiber therein for 60-80 min, then drain and dry to constant weight for later use; Step II, preparation of curing agent: adding calcium carbonate to the resin, stirring, then adding 1wt.% ammonium chloride solution, mixing evenly, and setting aside; Step III, preparation of flame retardant: mixing magnesium aluminum hydrotalcite and melamine phosphate into a ball mill and grinding until they are uniformly mixed; Step IV, pouring urea-formaldehyde resin glue, curing agent and flame retardant into the pretreated wood fiber in sequence, mixing evenly and then drying; Step V, pouring into a hot press and hot pressing to form a fiberboard; Step VI, mildew-proof treatment: soak and rinse the fiberboard in water, chitosan, AgNO3 solution and NaBH solution in sequence; Step VII, drying to obtain an ultra-thin mildew-proof and flame-retardant fiberboard; The weight proportions of the raw materials are as follows: 40-60 parts of wood fiber, 2.5-5 parts of urea-formaldehyde resin glue, 6-10 parts of curing agent, and 8-12 parts of flame retardant.

[0006] Preferably, in step I, the wood fiber is a poplar / pine mixed wood fiber with a length of 1 to 4 mm.

[0007] Preferably, in step I, the enzyme dosage of laccase is 35-45 U / g; the temperature is raised to 50-60° C.; the drying temperature is 60-65° C.; and the moisture content of the wood fiber after drying is 8-10%.

[0008] Preferably, in step II, the mass ratio of the ammonium chloride solution to the resin is 1:(4-4.5).

[0009] Preferably, in step III, the mass ratio of magnesium aluminum hydrotalcite to melamine phosphate is 1:(0.8-1); the ball mill rotates at 180-200 r / min, the grinding time is 15-18 min, and the ball mill rotates in reverse and alternately, with a forward / reverse time of 6 min.

[0010] Preferably, in step VI, the specific processing steps are: first rinse with clean water and then dry, then soak in 5g / L chitosan for 10-15min and then dry, then soak in 1g AgNO3 solution for 30-40min and then dry, and finally soak in 1g / L NaBH solution for 30-40min and then dry.

[0011] Preferably, the drying temperature is 60-70°C.

[0012] Preferably, in step VII, the thickness of the fiberboard is 1.0-1.2 mm.

[0013] The present invention provides a method for preparing an ultra-thin mildew-proof flame-retardant fiberboard. Compared with the prior art, the method has the following beneficial effects: the method for preparing an ultra-thin mildew-proof flame-retardant fiberboard significantly reduces the peak area of ​​oxygen-containing functional groups and hydroxyl functional groups of the fiberboard by soaking the wood fiber in laccase, thereby making it less likely to undergo a combustion reaction and improving the flame retardant performance of the fiberboard; by adding treated calcium carbonate and mixing it with the wood fiber, the flame retardant effect of the wood fiber is further improved; at the same time, melamine phosphate can promote the decomposition of magnesium aluminum hydrotalcite, reduce its decomposition temperature, and expand the temperature range of the flame retardant; by performing multiple soaking mildew-proof treatments on the fiberboard, its mildew-proof performance is effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Infrared spectra of wood fiber and laccase-treated wood fiber provided in a method for preparing an ultra-thin mildew-proof and flame-retardant fiberboard of the present invention; Figure 2 Total heat release provided for the method for preparing an ultra-thin mildew-proof and flame-retardant fiberboard of the present invention; Figure 3 A picture of the carbon residue after burning of a fiberboard provided for the method for preparing an ultra-thin mildew-proof and flame-retardant fiberboard of the present invention; Figure 4 A mildew resistance test is provided for the preparation method of an ultra-thin mildew resistance and flame retardant fiberboard of the present invention. DETAILED DESCRIPTION

[0015] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0016] Magnesium-aluminum hydrotalcite: average particle size 260nm, magnesium-aluminum ratio 3:1, MgO content 33.1%, Al2O3 content 20.5%; Urea-formaldehyde resin glue: solid content is 52%, viscosity is 60mPa·s (25℃), and pH value is 7.5.

[0017] Example 1 A method for preparing an ultra-thin mildew-proof and flame-retardant fiberboard comprises the following preparation steps: Step I, pretreatment of 1 mm long poplar / pine mixed wood fiber: pour 35 U / g laccase into 200 mL of citric acid-disodium hydrogen phosphate buffer, heat to 50° C., immerse 70 g of poplar / pine mixed wood fiber therein for 60 min, drain, dry at 60° C. to a moisture content of 8%, and set aside; Step II, preparation of curing agent: add 0.5g of calcium carbonate to 4g of resin, stir, then add 1g of 1wt.% ammonium chloride solution, mix well, and set aside; Step III, preparation of flame retardant: 1 g of magnesium aluminum hydrotalcite and 0.8 g of melamine phosphate were mixed and poured into a ball mill with a rotation speed of 180 r / min and ground for 15 min, and the ball mill rotated in reverse and forward directions alternately for 6 min until the mixture was uniformly mixed; Step IV: Pour 2.5 g of urea-formaldehyde resin glue, 6 g of curing agent and 8 g of flame retardant into 40 g of pretreated poplar / pine mixed wood fiber, mix well and dry; Step V, pouring into a hot press and hot pressing to obtain a fiberboard with a thickness of 1.0 mm; Step VI, mildew-proof treatment: first rinse with clean water and then dry, then soak in 5g / L chitosan for 10min and then dry, then soak in 1g AgNO3 solution for 30min and then dry, and finally soak in 1g / L NaBH solution for 30min and then dry, wherein the drying temperature is 60°C; Step VII: drying to obtain the ultra-thin mildew-proof and flame-retardant fiberboard.

[0018] Example 2 A method for preparing an ultra-thin mildew-proof and flame-retardant fiberboard comprises the following preparation steps: Step I, pretreatment of 2 mm long poplar / pine mixed wood fibers: pour laccase with an enzyme dosage of 40 U / g into 200 mL of citric acid-disodium hydrogen phosphate buffer, heat to 55° C., immerse 70 g of poplar / pine mixed wood fibers therein for 70 min, drain, dry at 65° C. to a moisture content of 9%, and set aside; Step II, preparation of curing agent: add 1g of calcium carbonate to 4g of resin, stir, then add 1g of 1wt.% ammonium chloride solution, mix well, and set aside; Step III, preparation of flame retardant: 1 g of magnesium aluminum hydrotalcite and 0.9 g of melamine phosphate were mixed and poured into a ball mill with a rotation speed of 190 r / min and ground for 16 min, and the ball mill rotated in reverse and forward directions alternately for 6 min until the mixture was uniformly mixed; Step IV: pour 3.5 g of urea-formaldehyde resin glue, 8 g of curing agent and 10 g of flame retardant into 50 g of pretreated poplar / pine mixed wood fiber, mix well and dry; Step V, pouring into a hot press and hot pressing to obtain a fiberboard with a thickness of 1.12 mm; Step VI, mildew-proof treatment: first rinse with clean water and then dry, then soak in 5g / L chitosan for 12min and then dry, then soak in 1g AgNO3 solution for 35min and then dry, and finally soak in 1g / L NaBH solution for 35min and then dry, wherein the drying temperature is 65°C; Step VII: drying to obtain the ultra-thin mildew-proof and flame-retardant fiberboard.

[0019] Example 3 A method for preparing an ultra-thin mildew-proof and flame-retardant fiberboard comprises the following preparation steps: Step I, pretreatment of 4 mm long poplar / pine mixed wood fibers: pour laccase with an enzyme dosage of 45 U / g into 200 mL of citric acid-disodium hydrogen phosphate buffer, heat to 60°C, place 70 g of poplar / pine mixed wood fibers in it for immersion treatment for 80 minutes, then drain, dry at 65°C to a moisture content of 10%, and set aside; Step II, preparation of curing agent: add 1g of calcium carbonate to 4.5g of resin, stir, then add 1g of 1wt.% ammonium chloride solution, mix well, and set aside; Step III, preparation of flame retardant: 1g of magnesium aluminum hydrotalcite and 1g of melamine phosphate were mixed and poured into a ball mill with a rotation speed of 200r / min and ground for 18min, and the ball mill rotated in reverse and forward directions alternately for 6min until the mixture was uniformly mixed; Step IV: pour 5 g of urea-formaldehyde resin glue, 10 g of curing agent and 12 g of flame retardant into 60 g of pretreated poplar / pine mixed wood fiber, mix well and dry; Step V, pouring into a hot press and hot pressing to obtain a fiberboard with a thickness of 1.2 mm; Step VI, mildew-proof treatment: first rinse with clean water and then dry, then soak in 5g / L chitosan for 15min and then dry, then soak in 1g AgNO3 solution for 40min and then dry, and finally soak in 1g / L NaBH solution for 40min and then dry, wherein the drying temperature is 70°C; Step VII: drying to obtain the ultra-thin mildew-proof and flame-retardant fiberboard.

[0020] Comparative Example 1 A method for preparing an ultra-thin mildew-proof and flame-retardant fiberboard comprises the following preparation steps: Step I, preparation of curing agent: add 0.5g of calcium carbonate to 4g of resin, mix well and set aside; Step II: Pour 2.5 g of urea-formaldehyde resin glue, 6 g of curing agent and 8 g of melamine phosphate into 40 g of poplar / pine mixed wood fiber, mix well and dry; Step II, pouring into a hot press and hot pressing to obtain a fiberboard with a thickness of 1.0 mm; Step III, mildew-proof treatment: first rinse with clean water and then dry, then soak in 1g AgNO3 solution for 30min and then dry, the drying temperature is 60℃; Step IV: drying to obtain the ultra-thin mildew-proof and flame-retardant fiberboard.

[0021] Cone calorimetry test: according to ISO5660 standard, the sample size is 100mm×100mm×4mm, and the radiation power is 50kW / m 2 .

[0022] Anti-mildew performance test: (1) Activate the bacteria (Aspergillus niger, Trichoderma viride) in a sterile operating room and culture them for 3 to 5 days. When the bacteria grow well, place them for later inoculation; (2) Wrap the sample with several layers of gauze and put it in a pressure steam sterilizer. Sterilize it at 0.1 MPa and 121°C for 30 minutes and set aside; (3) Pick a fixed-size bacterial block in a tissue grinder, add sterile water, grind it into a bacterial suspension of a certain concentration, transfer it to a sterilized spray bottle, and use the spray bottle to evenly spray the bacterial solution onto the surface of the sample in the culture dish. Culture it at a temperature of 25 to 30°C and a relative humidity of 80%; (4) Take samples every other cycle (10 days) to judge and analyze the anti-mildew effect.

[0023] like Figure 1 As shown, compared with untreated wood fibers, when wood fibers are immersed in laccase, laccase reacts with lignin to generate water, which can combine with OH to form hydrogen bonds, thereby significantly reducing the peak area of ​​its OH functional group. Therefore, the peak areas of oxygen-containing functional groups and hydroxyl functional groups of the fiberboard treated with laccase are significantly reduced. The reduction of such functional groups indicates that the fiberboard treated with laccase is not prone to combustion reactions, thereby improving the flame retardant properties of the fiberboard.

[0024] like Figure 2 As shown, the total heat release of the samples of Examples 1-3 is significantly reduced compared with that of Comparative Example 1, indicating that their flame retardant properties are improved.

[0025] like Figure 3 As shown, the carbon residue of the sample of comparative example 1 is grayish white powder, and the carbon layer has no mechanical strength. The carbon residue of the samples of embodiments 1-3 is grayish brown, and the surface density is significantly improved, indicating that the strength of the carbon layer is improved, thereby improving the flame retardant properties of the fiberboard.

[0026] like Figure 4 As shown, the anti-mildew effect of the samples of Examples 1-3 is significantly better than the anti-mildew effect of the sample of Comparative Example 1.

[0027] Meanwhile, the contents not described in detail in this specification belong to the prior art known to those skilled in the art.

[0028] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0029] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing an ultra-thin mildew-proof and flame-retardant fiberboard, characterized in that: The method comprises the following preparation steps: Step I: pretreatment of wood fiber: pour laccase into 200 mL of citric acid-disodium hydrogen phosphate buffer, and after heating, immerse 70 g of wood fiber therein for 60-80 min, then drain and dry to constant weight for later use; Step II, preparation of curing agent: adding calcium carbonate to the resin, stirring, then adding 1wt.% ammonium chloride solution, mixing evenly, and setting aside; Step III, preparation of flame retardant: mixing magnesium aluminum hydrotalcite and melamine phosphate into a ball mill and grinding until they are uniformly mixed; Step IV, pouring urea-formaldehyde resin glue, curing agent and flame retardant into the pretreated wood fiber in sequence, mixing evenly and then drying; Step V, pouring into a hot press and hot pressing to form a fiberboard; Step VI, mildew-proof treatment: soak and rinse the fiberboard in water, chitosan, AgNO3 solution and NaBH solution in sequence; Step VII, drying to obtain an ultra-thin mildew-proof and flame-retardant fiberboard; The weight proportions of the raw materials are as follows: 40-60 parts of wood fiber, 2.5-5 parts of urea-formaldehyde resin glue, 6-10 parts of curing agent, and 8-12 parts of flame retardant.

2. The method for preparing an ultra-thin mildew-proof and flame-retardant fiberboard according to claim 1, characterized in that: In the step I, the wood fiber is a poplar / pine mixed wood fiber with a length of 1-4 mm.

3. The method for preparing an ultra-thin mildew-proof and flame-retardant fiberboard according to claim 1, characterized in that: In the step I, the enzyme dosage of laccase is 35-45 U / g; the temperature is raised to 50-60° C.; the drying temperature is 60-65° C.; and the moisture content of the wood fiber after drying is 8-10%.

4. The method for preparing an ultra-thin mildew-proof and flame-retardant fiberboard according to claim 1, characterized in that: In step II, the mass ratio of calcium carbonate, ammonium chloride solution and resin is (0.5-1):1:(4-4.5).

5. The method for preparing an ultra-thin mildew-proof and flame-retardant fiberboard according to claim 1, characterized in that: In the step III, the mass ratio of magnesium aluminum hydrotalcite to melamine phosphate is 1: (0.8-1); the rotation speed of the ball mill is 180-200 r / min, the grinding time is 15-18 min, and the ball mill rotates in reverse and alternately, and the forward / reverse time is 6 min.

6. The method for preparing an ultra-thin mildew-proof and flame-retardant fiberboard according to claim 1, characterized in that: In step VI, the specific processing steps are: first rinse with clean water and then dry, then soak in 5g / L chitosan for 10-15min and then dry, then soak in 1g AgNO3 solution for 30-40min and then dry, and finally soak in 1g / L NaBH solution for 30-40min and then dry.

7. The method for preparing an ultra-thin mildew-proof and flame-retardant fiberboard according to claim 6, characterized in that: The drying temperature is 60-70°C.

8. The method for preparing an ultra-thin mildew-proof and flame-retardant fiberboard according to claim 1, characterized in that: In step VII, the thickness of the fiberboard is 1.0-1.2 mm.

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