Outdoor anti-corrosion, mildew-proof, insect-proof and waterproof plywood and preparation method thereof

Abstract

The present invention provides a corrosion-resistant, mildew-proof, insect-proof and waterproof plywood for outdoor use and a preparation method thereof. The method comprises the following steps: 1) preparing an anticorrosive, antimildew, anti-insect and waterproof adhesive; 2) impregnating plywood veneers with the adhesive obtained in step 1, or coating the plywood veneers according to thickness requirements of the plywood veneers; 3) drying the plywood veneers treated in step 2 to achieve a moisture content of 5.0-18.0%, and then subjecting the plywood veneers to plywood splicing, assembly, pre-pressing, hot pressing, edge trimming and sanding treatments to obtain an outdoor anticorrosive, antimildew, anti-insect and waterproof plywood; wherein, based on 100 parts, the anticorrosive, antimildew, anti-insect and waterproof adhesive comprises the following substances: 20-50 parts of modified phenolic resin, 0.3-3.0 parts of high-viscosity attapulgite, 0.5-5.0 parts of disodium ethylenediaminetetraacetic acid, 2.0-30.0 parts of a nano-microemulsion anticorrosive, antimildew and anti-insect agent, and the remaining component is water.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional artificial board production, and specifically comprises a plywood for outdoor use which is anti-corrosion, anti-mildew, anti-insect and waterproof, and a preparation method thereof. Background Art

[0002] The shrinkage, swelling, biological damage, decay, mildew, and insect damage of wood materials such as wood, fiberboard, particleboard, plywood, and wood flooring and their products are the main technical difficulties affecting their use in high-humidity and outdoor environments.

[0003] Due to the problems of shrinkage, swelling, decay, mildew and insect damage caused by high humidity and outdoor environments, plywood can only be used in dry indoor environments and short-term humid environments, and its scope of use is limited.

[0004] In order to improve the plywood's resistance to biological deterioration such as corrosion, insects and mildew, the veneer is usually impregnated with preservatives, mildew inhibitors and insect repellents, and then the anti-corrosion plywood is produced according to the plywood production process.

[0005] CN201210192237.5 discloses an anti-corrosion plywood and a method for producing the same. The selected anti-corrosion agent is one or a mixture of alkyl ammonium compounds, boron compounds, quaternary ammonium copper, copper azole or copper citrate, which is prepared into an aqueous solution for impregnating veneers. The veneers are then glued together using an adhesive such as a room temperature curing water-based polyurethane adhesive according to the plywood production process to prepare the anti-corrosion plywood.

[0006] CN201510143465.7 discloses a method for preparing anti-corrosion plywood. The plywood is produced by treating veneer with an anti-corrosion agent and applying an anti-corrosion adhesive. The anti-corrosion agents used to treat the veneer are furfuryl alcohol and ammonium borate, while the anti-corrosion adhesive is prepared by adding calcium borate (2-4% by mass of formaldehyde solution) to a urea-formaldehyde resin.

[0007] CN201510331206.7 discloses a method for preparing anti-corrosion plywood, which comprises impregnating a veneer with a preservative having a mass concentration of 1-3%, and then using phenolic resin as an adhesive to produce the anti-corrosion plywood according to a normal process.

[0008] CN202210016088.0 discloses a flame-retardant and anti-corrosion plywood and a preparation method thereof. The flame-retardant adhesive is prepared from the following raw materials in parts by weight: 3-5 parts of aluminum hydroxide, 3-5 parts of ammonium dihydrogen phosphate, 3-5 parts of calcium borate, 5-10 parts of modified expanded vermiculite, 0.5-3 parts of sodium dodecylsulfonate, 15-25 parts of methyl methacrylate, 40-60 parts of EVA emulsion, 5-15 parts of acrylic acid, and 8-12 parts of acrylamide. The flame retardant used for impregnation-treated veneers is composed of 4A molecular sieve, ammonium polyphosphate, borax, ditolyl phosphate, pentaerythritol, and water.

[0009] The aforementioned patents disclose methods for producing anti-corrosion plywood, all of which involve impregnating the veneer with a preservative or using an anti-corrosion adhesive. However, since the resulting veneer dimensional stability remains unchanged, the product's shrinkage and swelling, which hinder its use in high-humidity or outdoor environments, remains unresolved. Therefore, there is an urgent need to develop a plywood and its production process that is corrosion-resistant, mildew-resistant, insect-resistant, and waterproof for outdoor use, to overcome these shrinkage and swelling issues. Summary of the Invention

[0010] To address the aforementioned problems with the prior art, one object of the present invention is to provide a method for preparing plywood that is resistant to corrosion, mildew, insects, and water, especially for outdoor use. By treating plywood veneers with a self-prepared adhesive, the resulting plywood is resistant to corrosion, mildew, insects, and water, and can be used in highly humid and outdoor environments. This prevents problems such as shrinkage and swelling due to moisture, thus expanding the plywood's application range while maintaining its excellent mechanical properties, thus possessing broad industrial application value.

[0011] Another object of the present invention is to provide a plywood for outdoor use that is rot-resistant, mildew-resistant, insect-resistant and waterproof, prepared by the method described above.

[0012] To achieve the above first purpose, the technical solution adopted by the present invention includes:

[0013] The present invention discloses a method for preparing a plywood for outdoor use that is rot-resistant, mildew-resistant, insect-resistant and waterproof, comprising the following steps:

[0014] 1) Preparation of anti-corrosion, anti-mildew, anti-insect and waterproof adhesives;

[0015] 2) impregnating the plywood veneer with the adhesive obtained in step 1, or coating the plywood veneer according to the thickness requirement of the plywood veneer;

[0016] 3) drying the plywood veneer after the treatment in step 2 to a moisture content of 5.0-18.0%, and then splicing, assembling, pre-pressing, hot pressing, trimming, and sanding to obtain a plywood for outdoor use that is rot-resistant, mildew-resistant, insect-resistant, and waterproof;

[0017] Among them, based on 100 parts, the anti-corrosion, anti-mildew, anti-insect and waterproof adhesive is composed of the following substances: 20-50 parts of modified phenolic resin, 0.3-3.0 parts of high-viscosity attapulgite, 0.5-5.0 parts of disodium ethylenediaminetetraacetic acid, 2.0-30.0 parts of nano-microemulsion anti-corrosion, anti-mildew and anti-insect agent, and the remaining components are water.

[0018] In order to solve the technical bottleneck of plywood shrinkage and swelling due to humidity, as well as the functional problems of anti-corrosion, mildew resistance and insect resistance when used in high-humidity environments and outdoor environments, the present invention prepares a modified phenolic resin by an "acid-base" process, loads a nano-microemulsion anti-corrosion, mildew resistance and insect repellent, and prepares an anti-corrosion, mildew resistance and insect repellent adhesive. The adhesive is used to impregnate veneers so that it penetrates into the cell walls and cell cavities of the wood. During the hot pressing process of the plywood, the modified phenolic resin solidifies to form a polymer material, filling most of the pores in the wood, blocking the pore permeation channels in the wood, and significantly reducing the penetration of water into the pores and cell walls of the wood. The nano-microemulsion anti-corrosion, mildew resistance and insect repellent inhibits the reproduction of microorganisms in the wood, thereby producing anti-corrosion, mildew resistance, insect repellent and waterproof plywood for use in high-humidity environments and outdoor environments. For thin veneers ≤1.70mm thick, adhesive can be applied to each layer. During hot pressing, the adhesive melts and flows, penetrating the veneer. During this process, the modified phenolic resin solidifies, covering the wood surface and filling the wood pores, blocking moisture penetration and flow into the plywood, thereby improving the plywood's dimensional stability. For veneers ≤1.70mm thick, applying adhesive to each layer reduces the drying process after the veneers are impregnated with adhesive.

[0019] Furthermore, the nano-microemulsion antiseptic, mildew-proof and insect-proof agent consists of 5.0-30.0 parts of basic copper carbonate, 0.3-2.0 parts of tebuconazole, 0.3-2.0 parts of propiconazole, 0.1-1.0 parts of 4,5-dichloro-N-octyl-4-isothiazoline-3-one, 0.1-1.0 parts of iodopropynyl butyl carbamate, 0.02-0.10 parts of imidacloprid or pyrethroid, 2.0-15.0 parts of propylene glycol, 2.0-15.0 parts of dodecanol, 5.0-30.0 parts of ethanolamine, 1.0-5.0 parts of dimethylacetamide, 1.0-5.0 parts of ricinoleic acid, 2.0-15.0 parts of castor oil polyoxyethylene ether, 0.5-3.0 parts of wetting agent ABO, and 15.0-40.0 parts of water.

[0020] Furthermore, the nano-microemulsion antiseptic, mildew-proof and insect-proof agent consists of 10.0-20.0 parts of basic copper carbonate, 0.5-1.0 parts of tebuconazole, 0.5-1.0 parts of propiconazole, 0.2-0.5 parts of 4,5-dichloro-N-octyl-4-isothiazoline-3-one, 0.2-0.5 parts of iodopropynyl butyl carbamate, 0.05-0.08 parts of imidacloprid or pyrethroid, 5.0-10.0 parts of propylene glycol, 5.0-10.0 parts of dodecanol, 15.0-25.0 parts of ethanolamine, 2.0-4.0 parts of dimethylacetamide, 2.0-4.0 parts of ricinoleic acid, 5.0-10.0 parts of castor oil polyoxyethylene ether, 1.0-2.0 parts of wetting agent ABO and 25.0-30.0 parts of water.

[0021] Furthermore, high-viscosity attapulgite is added to the adhesive preparation as an adsorption carrier for the antiseptic, mildew-proof, and insect-proof agents in the nano-microemulsion, significantly improving their heat stability. The high-viscosity attapulgite also enhances the solution's suspending capacity and improves the uniformity of dispersion of the components in the suspension. The high-viscosity attapulgite complies with the Anhui Provincial Standard DB34 / T1057, and its product model and code include one or more of High Type I, High Type II, High Type III, Special Type I 601, Special Type I 701, or Special Type I 709. Preferably, the product model and code are selected from one or more of Special Type I 601 and Special Type I 701.

[0022] In one embodiment, the modified phenolic resin has a structure as shown in Formula I. The present invention utilizes an acid-base process to prepare the modified phenolic resin, which facilitates the formation of longer-chain benzene rings, increasing the toughness of the phenolic resin and significantly improving the strength and moisture resistance of medium-density fiberboard. Specifically, phenol and formaldehyde, in an acidic environment with a formaldehyde / phenol molar ratio of less than 1.0, first generate linear benzene rings. Subsequently, formaldehyde is added in an alkaline environment to produce a resin with side chains, enhancing the toughness of the phenolic resin. During the plywood hot pressing process, the phenolic resin solidifies, coating the wood surface and filling the wood pores, blocking moisture penetration and flow into the plywood. This achieves the dual functions of enhancing the plywood's dimensional stability and waterproofing, improving the strength and waterproofing of the wood-based board.

[0023]

[0024] The anticorrosive, mildew-proof, insect-proof and waterproof adhesive is prepared according to the following method:

[0025] 1) Preparation of modified phenolic resin:

[0026] (1) Add a certain amount of phenol to the reactor, heat it to 50-60°C, add phosphoric acid, and keep it for 10-15 minutes;

[0027] (2) Add formaldehyde once, raise the temperature to 93-98°C, and maintain for 60-240 minutes;

[0028] (3) Cool to 70-75°C and adjust the pH to 8.0-10.0 with sodium hydroxide;

[0029] (4) slowly adding secondary formaldehyde and maintaining at 90-95°C for 30-120 minutes;

[0030] (5) slowly adding tertiary formaldehyde to make the molar ratio of (primary formaldehyde + secondary formaldehyde + tertiary formaldehyde) / phenol be 1.6-2.1, controlling the reaction temperature at 93-98° C., testing the viscosity of the resin, and when the viscosity is 15-60 cps, cooling to below 50° C. to obtain a modified phenolic resin;

[0031] 2) Preparation of adhesive:

[0032] Add disodium ethylenediaminetetraacetic acid to the modified phenolic resin, stir for 5-10 minutes, then add high viscosity attapulgite, continue stirring for 10-20 minutes; add nano-microemulsion antiseptic, mildew proof and insect repellent, mix well to obtain the product.

[0033] Furthermore, in step 1, the molar ratio of phosphoric acid to phenol is 0.02-0.04:1; in step 2, the molar ratio of primary formaldehyde to phenol is 0.45-0.85:1; in step 4, the molar ratio of secondary formaldehyde to phenol is 0.20-1:1, so that the molar ratio of (primary formaldehyde+secondary formaldehyde) / phenol is 1.1-1.5.

[0034] Furthermore, the hot pressing temperature is 125-150° C., the hot pressing time is 50-70 s / mm, and the pressure condition is 0.8-1.5 MPa.

[0035] Furthermore, in step 2, the processing amount of adhesive used per cubic meter of plywood veneer is 40-300 kg.

[0036] To achieve the above second purpose, the technical solutions adopted by the present invention include:

[0037] The present invention discloses a corrosion-resistant, mildew-resistant, insect-resistant, and waterproof plywood for outdoor use, prepared using the above-described method. By treating the plywood veneer with a self-made adhesive, the resulting plywood can be corrosion-resistant, mildew-resistant, insect-resistant, and waterproof for use in highly humid and outdoor environments, preventing problems such as shrinkage due to drying and swelling due to moisture. This expands the plywood's application range while maintaining its excellent mechanical properties, resulting in widespread industrial application value.

[0038] Beneficial effects of the present invention:

[0039] The outdoor anti-corrosion, anti-mildew, anti-insect and waterproof plywood prepared by the method of the present invention has a bonding strength that meets the requirements of Class I products of GB / T 9846-2015 "Ordinary Plywood" and meets the requirements for use in humid conditions and outdoor conditions; the water absorption thickness expansion rate of the product is less than 2%, and the dimensional stability is significantly enhanced; the anti-corrosion performance of the product meets the strong corrosion resistance level of GB / T13942.1-2009 "Durability of Wood Part 1: Laboratory Test Method for Natural Corrosion Resistance"; the anti-mildew performance meets the level 0 (strong mildew resistance level) of LY / T2230-2013 "Evaluation of Anti-mildew Performance of Artificial Boards"; and the anti-insect performance meets the level 10 (intact) of GB / T18260-2015 "Laboratory Test Method for Toxic Effect of Wood Preservatives on Termites". The product meets the requirements for use in occasions with high restrictions on corrosion resistance and water resistance of plywood, expands the application range of plywood, and at the same time ensures the good mechanical properties of plywood, thus having broad industrial promotion value. DETAILED DESCRIPTION

[0040] To more clearly illustrate the present invention, the present invention is further described below in conjunction with preferred embodiments. It should be understood that the embodiments described are only a portion of the present invention, not all of the embodiments. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are intended to fall within the scope of protection of the present invention.

[0041] Example 1

[0042] 1) Preparation of modified phenolic resin:

[0043] (1) Add 1.0 mol of phenol and an appropriate amount of water to a reaction kettle, start the stirring device, raise the temperature to 50-60°C, add 0.03 mol of 85% phosphoric acid, and maintain for 10-15 minutes;

[0044] (2) adding 38.0 kg of 0.47 mol% formaldehyde solution (37.0%), with a formaldehyde / phenol molar ratio of 0.47, and heating to 93-95° C. for 35 minutes;

[0045] (3) Cool to 73-75°C and adjust the pH to 8.5-9.0 with caustic soda;

[0046] (4) slowly adding 0.77 mol% of 37.0% formaldehyde solution with a (primary formaldehyde + secondary formaldehyde) / phenol molar ratio of 1.24, and maintaining the temperature at 90-93°C for 60 minutes;

[0047] (5) Slowly adding 0.44 mol% formaldehyde solution (37.0%), with a molar ratio of (primary formaldehyde + secondary formaldehyde + tertiary formaldehyde) to phenol of 1.68, controlling the reaction temperature at 93-95°C, testing the viscosity of the resin, and lowering the temperature to below 50°C when the viscosity is 35-38 cps;

[0048] 2) Preparation of adhesive:

[0049] Add 2% phenol content of disodium ethylenediaminetetraacetate to the modified phenolic resin and stir for 5 minutes; add 3.00% phenol content of high viscosity attapulgite and stir for 10 to 20 minutes; add 40% phenol content of nano-microemulsion antiseptic, mildew-proof and insect repellent and stir for 15 minutes;

[0050] The nano-microemulsion antiseptic, mildew-proof and insect-proof agent consists of 16.71 parts of basic copper carbonate, 0.67 parts of tebuconazole, 0.67 parts of propiconazole, 0.33 parts of 4,5-dichloro-N-octyl-4-isothiazoline-3-one, 0.33 parts of iodopropynyl butyl carbamate, 0.067 parts of imidacloprid, 6.68 parts of propylene glycol, 6.68 parts of dodecanol, 23.4 parts of ethanolamine, 2.67 parts of dimethylacetamide, 3.34 parts of ricinoleic acid, 6.68 parts of castor oil polyoxyethylene ether, 1.67 parts of wetting agent ABO and 30.10 parts of water.

[0051] 3) Preparation of anti-corrosion, anti-mildew, anti-insect and waterproof plywood for outdoor use

[0052] The composition of the materials of the anti-corrosion, anti-mildew, anti-insect and waterproof adhesives is shown in Table 1;

[0053] (1) Poplar veneers with a thickness of 1.70 mm were dried to a moisture content of 8.0-10%, and spliced ​​into whole veneers of 1270*2480 mm using a splicing machine;

[0054] (2) Add 30 parts of flour to 100 parts of adhesive and mix well;

[0055] (3) Apply glue to each layer of veneer. The material composition of each cubic meter of product is shown in Table 2;

[0056] (4) Assemble the blanks according to the plywood structure, using 0.15-0.20 mm technical wood veneer on the upper and lower surfaces, with 11 layers of glued veneer in the middle, the blank thickness is 19.0 mm, and the nominal thickness of the product is 18.00 mm;

[0057] (5) aging the opened pieces for 1 to 2 hours, followed by pre-pressing for 2 to 4 hours, and hot pressing for 20 minutes at a temperature of 135 to 140° C. and a unit pressure of 1.0 to 1.1 MPa;

[0058] (6) After cooling, the edges are trimmed and sanded to produce plywood that is anti-corrosion, anti-mildew, anti-insect and waterproof; the product performance is shown in Table 3.

[0059] Example 2-3

[0060] (1) The preparation process of the modified phenolic resin and the adhesive is the same as that in Example 1. The feeding amount of each material is shown in Table 1.

[0061] (2) After drying, the poplar veneer with a thickness of 1.70 mm has a moisture content of 8.0-10%, and is spliced ​​into a whole veneer of 1270*2480 mm using a splicing machine;

[0062] (3) Add 30 parts of flour to 100 parts of adhesive and mix well;

[0063] (4) Apply glue to each layer of veneer. The material composition of each cubic meter of product is shown in Table 2;

[0064] (5) Assemble the blanks according to the plywood structure, using 0.15-0.20mm technical wood veneer on the upper and lower surfaces, with 11 layers of glued veneer in the middle, the blank thickness is 19.0mm, and the nominal thickness of the product is 18.00mm;

[0065] (6) aging the opened pieces for 1 to 2 hours, followed by pre-pressing for 2 to 4 hours, and hot pressing for 20 minutes at a temperature of 135 to 140° C. and a unit pressure of 1.0 to 1.1 MPa;

[0066] (7) After cooling, the edges are trimmed and sanded to produce plywood that is anti-corrosion, anti-mildew, anti-insect and waterproof; the product performance is shown in Table 3.

[0067] Examples 4 to 6

[0068] (1) The preparation process of the modified phenolic resin and the adhesive is the same as that of Example 1. The viscosity of the resin is 16-20 cps. The feeding amount of each material is shown in Table 1.

[0069] (2) Poplar veneer sheets with a thickness of 2.20 mm (moisture content of 15.0-22.0%) were impregnated with an anticorrosive, anti-mildew, anti-insect, and waterproof adhesive in a vacuum impregnation tank at a vacuum degree of -0.03 MPa for 15 minutes. The material composition per cubic meter of product is shown in Table 2.

[0070] (3) Dry the veneer to a moisture content of 12.0-18.0%, and splice it into a whole veneer of 1270*2480mm using a splicing machine;

[0071] (4) Assemble the blanks according to the plywood structure, using 0.15-0.20mm technical wood veneer on the upper and lower surfaces, with 11 layers of impregnated veneer in the middle, the blank thickness is 19.0mm, and the nominal thickness of the product is 18.00mm;

[0072] (5) pre-pressing for 4 to 12 hours, and hot pressing for 20 minutes at a temperature of 135 to 140°C and a unit pressure of 1.0 to 1.1 MPa;

[0073] (6) After cooling, the edges are trimmed and sanded to produce plywood that is anti-corrosion, anti-mildew, anti-insect and waterproof; the product performance is shown in Table 3.

[0074] Examples 7-8

[0075] (1) The preparation process of the modified phenolic resin and the adhesive is the same as that of Example 1. The viscosity of the resin is 16-20 cps. The feeding amount of each material is shown in Table 1.

[0076] (2) Poplar veneer sheets with a thickness of 2.20 mm (moisture content of 15.0-22.0%) were impregnated with an anticorrosive, anti-mildew, anti-insect, and waterproof adhesive in a vacuum impregnation tank at a vacuum degree of -0.03 MPa for 20 minutes. The material composition per cubic meter of product is shown in Table 2.

[0077] (3) Dry the veneer to a moisture content of 12.0-18.0%, and splice it into a whole veneer of 1270*2480mm using a splicing machine;

[0078] (4) Assemble the blanks according to the plywood structure, using 0.15-0.20mm technical wood veneer on the upper and lower surfaces, with 11 layers of impregnated veneer in the middle, the blank thickness is 19.0mm, and the nominal thickness of the product is 18.00mm;

[0079] (5) pre-pressing for 4 to 12 hours, and hot pressing for 20 minutes at a temperature of 135 to 140°C and a unit pressure of 1.0 to 1.1 MPa;

[0080] (6) After cooling, the edges are trimmed and sanded to produce plywood that is anti-corrosion, anti-mildew, anti-insect and waterproof; the product performance is shown in Table 3.

[0081] Example 9

[0082] (1) The preparation process of the modified phenolic resin and the adhesive is the same as that of Example 1. The viscosity of the resin is 16-20 cps. The feeding amount of each material is shown in Table 1.

[0083] (2) Poplar veneer sheets with a thickness of 2.20 mm (moisture content of 15.0-22.0%) were impregnated with an anticorrosive, anti-mildew, anti-insect, and waterproof adhesive in a vacuum impregnation tank at a vacuum degree of -0.03 MPa for 60 minutes. The material composition per cubic meter of product is shown in Table 2.

[0084] (3) Dry the veneer to a moisture content of 12.0-18.0%, and splice it into a whole veneer of 1270*2480mm using a splicing machine;

[0085] (4) Assemble the blanks according to the plywood structure, using 0.15-0.20mm technical wood veneer on the upper and lower surfaces, with 11 layers of impregnated veneer in the middle, the blank thickness is 19.0mm, and the nominal thickness of the product is 18.00mm;

[0086] (5) pre-pressing for 4 to 12 hours, and hot pressing for 20 minutes at a temperature of 135 to 140°C and a unit pressure of 1.0 to 1.1 MPa;

[0087] (6) After cooling, the edges are trimmed and sanded to produce plywood that is anti-corrosion, anti-mildew, anti-insect and waterproof; the product performance is shown in Table 3.

[0088] Table 1-1 Material composition of adhesive

[0089]

[0090] Comparative Example 1

[0091] (1) Poplar veneers with a thickness of 1.70 mm were dried to a moisture content of 8.0-10%, and spliced ​​into whole veneers of 1270*2480 mm using a splicing machine;

[0092] (2) The material composition of the phenolic resin for plywood (formaldehyde / phenol molar ratio = 1.62, resin solid content 45.2%) is shown in Table 1.2. 100 parts of phenolic resin is added to 30 parts of flour and stirred evenly;

[0093] (3) For veneer gluing, the material composition of each cubic meter of product is shown in Table 2;

[0094] (5) Assemble the blanks according to the plywood structure, using 0.15-0.20mm technical wood veneer on the upper and lower surfaces, with 11 layers of glued veneer in the middle, the blank thickness is 19.0mm, and the nominal thickness of the product is 18.00mm;

[0095] (6) aging the opened pieces for 1 to 2 hours, followed by pre-pressing for 2 to 4 hours, and hot pressing for 20 minutes at a temperature of 135 to 140° C. and a unit pressure of 1.0 to 1.1 MPa;

[0096] (7) After cooling, the edges are aligned and sanded to produce waterproof plywood; the product properties are shown in Table 3.

[0097] Comparative Example 2

[0098] (1) Dilute the impregnation phenolic resin with water to prepare a working solution with a solid content of 31%. The material composition is shown in Table 1-2;

[0099] (2) Poplar veneer sheets with a thickness of 2.20 mm (moisture content of 15.0-22.0%) were impregnated with a modified phenolic resin for corrosion resistance, mildew resistance, insect resistance, and waterproofing in a vacuum impregnation tank at a vacuum degree of -0.03 MPa for 20 minutes. The material composition per cubic meter of product is shown in Table 2.

[0100] (3) Dry the veneer to a moisture content of 12.0-18.0%, and splice it into a whole veneer of 1270*2480mm using a splicing machine;

[0101] (4) Assemble the blanks according to the plywood structure, using 0.15-0.20mm technical wood veneer on the upper and lower surfaces, with 11 layers of impregnated veneer in the middle, the blank thickness is 19.0mm, and the nominal thickness of the product is 18.00mm;

[0102] (5) Pre-pressing for 4 to 12 hours, and hot pressing for 20 minutes at a temperature of 135 to 140°C and a unit pressure of 1.0 to 1.1 MPa;

[0103] (6) After cooling, the edges are aligned and sanded to produce waterproof plywood; the product properties are shown in Table 3.

[0104] Comparative Example 3

[0105] (1) The synthesis of the modified phenolic resin and the adhesive and the production process of the product are shown in Example 1. A nano-microemulsion antiseptic, mildew-proof and insect-proof agent with a phenol feed amount of 60% is added. The composition of the modified phenolic resin material is shown in Table 1-2;

[0106] (2) The material composition of each cubic meter of product is shown in Table 2; the performance of the product is shown in Table 3.

[0107] Comparative Example 4

[0108] (1) The synthesis of the modified phenolic resin and the adhesive and the production process of the product are shown in Example 4. A nano-microemulsion antiseptic, mildew-proof and insect-proof agent with a phenol feed amount of 60% is added. The composition of the modified phenolic resin material is shown in Table 1-2;

[0109] (2) The material composition of each cubic meter of product is shown in Table 2; the performance of the product is shown in Table 3.

[0110] Comparative Example 5

[0111] (1) The synthesis of the modified phenolic resin and adhesive and the production process of the product are shown in Example 7. A nano-microemulsion antiseptic, mildew-proof and insect-proof agent with a phenol feed amount of 75% is added. The composition of the modified phenolic resin material is shown in Table 1-2;

[0112] (2) The material composition of each cubic meter of product is shown in Table 2; the performance of the product is shown in Table 3.

[0113] Table 1-2 Material composition of adhesives

[0114] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 phenol 29.77 18.63 25.83 17.66 16.48 water 25.31 49.49 17.84 41.29 40.25 85% phosphoric acid 0.00 0.00 0.83 0.57 0.53 37% formaldehyde solution 41.76 29.70 37.49 28.43 28.59 40% sodium hydroxide solution 3.16 2.18 1.23 0.94 0.96 Sodium EDTA-2 0.517 0.353 0.330 High viscosity attapulgite 0.775 0.157 0.495 Nano-microemulsion antiseptic, mildew-proof and insect repellent 15.496 10.598 12.363 Total input 100.00 100.00 100.00 100.00 100.00

[0115] Table 2 Material composition of the product

[0116]

[0117]

[0118] Note: The data in Table 2 is based on the amount of modified phenolic resin used per cubic meter (including pure modified phenolic resin and anti-corrosion, anti-mildew and anti-insecticide), converted to the amount of wood, pure modified phenolic resin and anti-corrosion, anti-mildew and anti-insecticide per 100 parts of finished product.

[0119] Table 3 Product performance

[0120]

[0121] As can be seen from Tables 1 to 3, the plywood produced using the adhesive of the present invention has a bonding strength that meets the requirements of Class I products in GB / T9846-2015 "Ordinary Plywood" and meets the requirements for use in humid and outdoor conditions; the water absorption thickness expansion rate of the product is less than 2%, and can even reach less than 0.50%, and the dimensional stability is significantly enhanced; the anti-corrosion performance of the product meets the strong corrosion resistance level of GB / T13942.1-2009 "Durability of Wood Part 1: Laboratory Test Method for Natural Corrosion Resistance"; the mildew resistance performance meets Level 0 (strong mildew resistance level) of LY / T2230-2013 "Evaluation of Mildew Resistance of Artificial Boards"; and the insect resistance performance meets Level 10 (intact) of GB / T18260-2015 "Laboratory Test Method for Toxic Effect of Wood Preservatives on Termites".

[0122] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A method for preparing outdoor anti-corrosion, anti-mildew, anti-insect and waterproof plywood, characterized in that: The following steps are involved: 1) Preparation of anti-corrosion, anti-mildew, anti-insect and waterproof adhesives; 2) impregnating the plywood veneer with the adhesive obtained in step 1, or coating the plywood veneer according to the thickness requirement of the plywood veneer; 3) drying the plywood veneer after the treatment in step 2 to a moisture content of 5.0-18.0%, and then performing paneling, assembly, pre-pressing, hot pressing, edge trimming, and sanding to obtain a plywood for outdoor use that is rot-resistant, mildew-resistant, insect-resistant, and waterproof; The anti-corrosion, anti-mildew, anti-insect and waterproof adhesive is composed of the following substances per 100 parts: 20-50 parts of modified phenolic resin, 0.3-3.0 parts of high-viscosity attapulgite, 0.5-5.0 parts of disodium ethylenediaminetetraacetic acid, 2.0-30.0 parts of nano-microemulsion anti-corrosion, anti-mildew and anti-insect agent, and the remaining component is water; The anti-corrosion, anti-mildew, anti-insect and waterproof adhesive is prepared according to the following method: 1) Preparation of modified phenolic resin: (1) Add a certain amount of phenol to the reactor, heat it to 50-60°C, add phosphoric acid, and keep it for 10-15 minutes; (2) Add formaldehyde once, raise the temperature to 93-98°C, and maintain for 60-240 minutes; (3) Cool down to 70-75°C and adjust the pH to 8.0-10.0 with sodium hydroxide; (4) Slowly add secondary formaldehyde and maintain at 90-95°C for 30-120 minutes; (5) Slowly add tertiary formaldehyde to make the molar ratio of (primary formaldehyde + secondary formaldehyde + tertiary formaldehyde) / phenol be 1.6-2.1, control the reaction temperature at 93-98°C, test the viscosity of the resin, and when the viscosity is 15-60 cps, cool to below 50°C to obtain a modified phenolic resin; 2) Preparation of adhesive: Add disodium ethylenediaminetetraacetic acid to the modified phenolic resin, stir for 5-10 minutes, then add high viscosity attapulgite, continue stirring for 10-20 minutes; add nano-microemulsion antiseptic, mildew proof and insect repellent, mix well to obtain the product.

2. The preparation method according to claim 1, characterized in that The nano-microemulsion antiseptic, mildew-proof and insect-proof agent comprises 5.0-30.0 parts of basic copper carbonate, 0.3-2.0 parts of tebuconazole, 0.3-2.0 parts of propiconazole, 0.1-1.0 parts of 4,5-dichloro-N-octyl-4-isothiazoline-3-one, 0.1-1.0 parts of iodopropynyl butyl carbamate, 0.02-0.10 parts of imidacloprid or pyrethroid, 2.0-15.0 parts of propylene glycol, 2.0-15.0 parts of dodecanol, 5.0-30.0 parts of ethanolamine, 1.0-5.0 parts of dimethylacetamide, 1.0-5.0 parts of ricinoleic acid, 2.0-15.0 parts of castor oil polyoxyethylene ether, 0.5-3.0 parts of wetting agent ABO and 15.0-40.0 parts of water.

3. The preparation method according to claim 1, characterized in that The nano-microemulsion antiseptic, mildew-proof and insect-proof agent comprises 10.0-20.0 parts of basic copper carbonate, 0.5-1.0 parts of tebuconazole, 0.5-1.0 parts of propiconazole, 0.2-0.5 parts of 4,5-dichloro-N-octyl-4-isothiazoline-3-one, 0.2-0.5 parts of iodopropynyl butyl carbamate, 0.05-0.08 parts of imidacloprid or pyrethroid, 5.0-10.0 parts of propylene glycol, 5.0-10.0 parts of dodecanol, 15.0-25.0 parts of ethanolamine, 2.0-4.0 parts of dimethylacetamide, 2.0-4.0 parts of ricinoleic acid, 5.0-10.0 parts of castor oil polyoxyethylene ether, 1.0-2.0 parts of wetting agent ABO and 25.0-30.0 parts of water.

4. The preparation method according to claim 1, characterized in that The high viscosity attapulgite is in compliance with the Anhui provincial local standard DB34 / T1057.

5. The preparation method according to claim 1, characterized in that In step 1, the molar ratio of phosphoric acid to phenol is 0.02-0.04:1; in step 2, the molar ratio of primary formaldehyde to phenol is 0.45-0.85:1; in step 4, the molar ratio of secondary formaldehyde to phenol is 0.20-1:1, so that the molar ratio of (primary formaldehyde+secondary formaldehyde) / phenol is 1.1-1.

5.

6. The preparation method according to claim 1, characterized in that The hot pressing temperature is 125-150°C, the hot pressing time is 50-70s / mm, and the pressure condition is 0.8-1.5MPa.

7. The preparation method according to claim 1, characterized in that In step 2, the treatment amount of the anti-corrosion, anti-mildew, anti-insect and waterproof adhesive used per cubic meter of plywood veneer is 40-300 kg.

8. A plywood for outdoor use that is rot-resistant, mildew-resistant, insect-resistant and waterproof, characterized in that: The method is prepared by the method according to any one of claims 1 to 7.

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