Manufacturing process of bean pulp modified adhesive formaldehyde-free shaving board

Abstract

The invention belongs to the technical field of wood processing, and relates to a manufacturing process of a soybean meal modified adhesive formaldehyde-free shaving board, which comprises the following steps: chipping of wood materials, flaking, wood shaving drying, screening, glue mixing and applying, paving, pre-pressing, hot pressing, edge cutting, cooling, hardening and tempering, sanding, inspection and grading, and packaging and warehousing, the moisture content of the dried wood shavings is 2.0-3.0%; in the step of glue mixing and applying, surface layer and core layer layered glue applying is adopted, an adhesive of the surface layer is a mixture of a soybean meal modified adhesive and MDI, an adhesive of the core layer is MDI, and the applying amount of each component is calculated according to the mass ratio of the absolutely dry component to the absolutely dry wood shavings of the corresponding layer. According to the manufacturing method, the soybean meal modified adhesive is adopted, on the basis that the manufactured shaving board meets the mechanical property index, the formaldehyde emission reaches the highest grading standard ENF grade, batch continuous production can be achieved, good formability is provided, the limitation of the water content on production can be reduced through matched use of the soybean meal modified adhesive and MDI, and the production efficiency is guaranteed.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wood processing, and relates to the manufacturing of a shaving board, in particular to a manufacturing process of a soybean meal modified adhesive formaldehyde-free shaving board. BACKGROUND

[0002] The shaving board is also called a particle board, which is cut into fragments of a certain specification from various branches, small-diameter wood, fast-growing wood, wood chips and the like, dried, mixed with glue, hardener, waterproof agent and the like, and pressed into a kind of artificial board under certain temperature and pressure.

[0003] At present, three aldehyde glue is still mainly used in the production of artificial boards, but as the market has higher and higher requirements on the low formaldehyde emission of furniture, formaldehyde-free and low-carbon shaving boards have become the key to promoting the green development of the industry. However, the shaving board based on three aldehyde glue has been difficult to meet the quality requirements of the market for formaldehyde-free shaving boards. Under the multiple pressures of output ratio, environmental protection, quality and cost, only the formaldehyde-free shaving board with low cost and high quality can cope with the fierce market competition.

[0004] In recent years, practitioners have turned their attention to the production of shaving boards with soybean glue, trying to use soybean glue to replace isocyanate glue to produce formaldehyde-free shaving boards, but many problems existing in the use process limit the application of soybean glue, for example:

[0005] (1) The soybean glue has large viscosity and poor wettability, and it is difficult to be uniformly and effectively sprayed onto the shaving, which affects the performance of the board due to poor glue application effect;

[0006] (2) The soybean glue has poor initial adhesion and slow curing, and if the amount of glue applied is small, problems such as board surface cracking and edge collapse may occur, and if the amount of glue applied is increased to ensure the paving quality, the water content is too high, which may cause bubbling, and in order to avoid bubbling, the production speed needs to be reduced to allow the glue to fully cure and exhaust, which greatly reduces the production efficiency, and it is difficult to balance the board surface quality and production efficiency;

[0007] (3) The soybean glue itself has poor water resistance and is prone to mold. SUMMARY

[0008] In view of the technical problems existing in the production of shaving boards with soybean glue, the purpose of the present application is to provide a manufacturing process of a soybean meal modified adhesive formaldehyde-free shaving board, which adopts one-time glue spraying technology, and the process of mixing soybean powder and liquid glue twice is more uniform, and the glue application is more uniform, which can maximize the crosslinking. Through the reasonable application of tackifier and MDI and the control of the process, the board quality and production efficiency are maximized.

[0009] TECHNICAL SCHEME

[0010] A manufacturing process of a soybean meal modified adhesive formaldehyde-free shaving board, comprising the following steps: wood material slicing, slicing, shaving drying, screening, glue application, laying, pre-pressing, hot pressing, edge cutting, cooling, conditioning, sanding, testing and grading, and packaging and warehousing, wherein:

[0011] In the drying step, the water content of the dried shavings is 2.0-3.0%.

[0012] In the glue application step, layered application of the top and core layers is adopted, including application of the adhesive, tackifier and waterproof agent of the top layer, and application of the adhesive of the core layer, wherein the adhesive of the top layer is a mixture of the soybean meal modified adhesive and MDI, the adhesive of the core layer is MDI, and the application amount of each component is calculated according to the mass ratio of the absolute dry component to the absolute dry shavings of the corresponding layer.

[0013] Further, in the top layer, the addition amount of the soybean meal modified adhesive is 2-6%, and the addition amount of MDI is 0.3-3.5%.

[0014] Further, the soybean meal modified adhesive and MDI are respectively sprayed through separate pipes at the same time and uniformly stirred with the top layer shavings.

[0015] Further, the tackifier is one or more of polyvinyl alcohol solution, polyvinyl acetate, acrylic ester, carboxymethyl cellulose and carrageenan, preferably polyvinyl alcohol solution, and the addition amount is 0.2-2%.

[0016] Further, the waterproof agent is emulsified paraffin, and the addition amount is 0.5-1.5%.

[0017] Further, the addition amount of the core layer adhesive MDI is 0.5-4%, and the core layer MDI is uniformly stirred with the core layer shavings through a core layer glue application system.

[0018] In the laying step of the preferred disclosure of the present application, the water content of the shavings after top layer glue application is 15-18%, and the water content of the shavings after core layer glue application is 4-7%.

[0019] In the hot pressing step of the preferred disclosure of the present application, the hot pressing temperature is 200-240℃, the hot pressing pressure is 0-3.5MPa, and the hot pressing factor is 6-10s / mm.

[0020] The soybean meal modified adhesive used in the present application is purchased from Guangxi Nanning Linjing New Material Co., Ltd., the model number is XHST-008, and the solid content is 30-40%; the tackifier is purchased from Guangxi Nanning Linjing New Material Co., Ltd., the model number is XHST-N0250; and the MDI is purchased from Wanhua Chemical Group Co., Ltd.

[0021] The present application has the following improvements for the problems existing in the application of soybean glue in the flakeboard: first, the soybean powder and glue solution are mixed first to make the gluing more uniform by using one-time glue spraying process, in order to avoid the problem of difficult spraying due to high viscosity after mixing, a low-viscosity soybean meal modified adhesive is selected, and the problem of poor wettability of soybean glue is solved; second, soybean meal modified adhesive and MDI are used in the surface layer, the soybean meal modified adhesive is used as the main adhesive in the surface layer, and MDI is used for reinforcement and catalysis, experiments show that a small amount of MDI added in the soybean meal glue can effectively reduce the curing temperature required by the soybean meal glue, therefore, a small amount of MDI can not only increase the strength, but also improve the production efficiency, and improve the mildew resistance and water resistance; in order to avoid the advance reaction of MDI and soybean meal glue in the pipeline, the mixed soybean meal glue and MDI are sprayed through separate pipelines at the same time, which can maximize the mixing of soybean meal glue and MDI and uniformly wrap the shavings; third, the moisture content of the shavings after gluing the surface layer is controlled at 15-18%, which can relax the restriction on the amount of soybean meal glue, and can improve the preformability of the board, the higher moisture content can improve the heat transfer efficiency of hot pressing, so that the heat can reach the core layer faster, the moisture content of the shavings after gluing the core layer is controlled at 4-7%, the discharge of water vapor in the core layer is reduced, and the second point mentioned that the catalysis of MDI to soybean glue can make the board have enough strength faster, so that the board will not be slow in curing and the strength will not follow due to high moisture content in the surface layer, and the bubbling and board explosion caused by high moisture content and large amount of gluing of general soybean glue flakeboard can be effectively avoided.

[0022] Advantages

[0023] The present application uses soybean meal modified adhesive, which does not contain toxic and harmful substances such as formaldehyde and phenol, and the flakeboard made of the soybean meal modified adhesive can meet the mechanical property index, the formaldehyde emission can reach the highest standard ENF grade, and batch continuous production can be realized; the use of the soybean meal modified adhesive as the main adhesive in the surface layer and the control of the process can provide good formability, the use of the soybean meal modified adhesive and MDI can reduce the restriction of moisture content on production, ensure production efficiency, and produce flakeboards with superior performance when the hot pressing factor reaches 6 s / mm. The soybean meal modified adhesive itself is friendly in price, and as the main adhesive in the surface layer, it is easier to control the cost of glue. DETAILED DESCRIPTION

[0024] The present application will be described in detail below with reference to the embodiments, so that those skilled in the art can better understand the present application, but the present application is not limited to the following embodiments.

[0025] Example 1

[0026] A manufacturing process of a soybean meal modified adhesive formaldehyde-free flakeboard with a thickness of 18mm, comprising the following steps:

[0027] 1. Wood material slicing→flaking→flakes drying (flakes moisture content after drying is about 2.0%)→screening;

[0028] 2. Surface layer flakes and core layer flakes are respectively treated with modified soybean meal adhesive: the surface layer flakes are added with 3% of modified soybean meal adhesive, 1% of MDI, 1% of tackifier and 0.8% of emulsified paraffin relative to the absolute dry flakes of the surface layer through a glue application system; the core layer flakes are added with 1.5% of MDI relative to the absolute dry flakes of the core layer through the glue application system;

[0029] 3. The moisture content of the surface layer flakes after glue application is about 16%, and the moisture content of the core layer flakes is about 5.5%;

[0030] 4. The lower surface layer+core layer+upper surface layer are respectively layered and laid through a laying system, and the board is prepared after pre-pressing and hot pressing, the hot pressing factor is 6 s / mm, and the hot pressing temperature is 230°C.

[0031] The performance of the 18mm flake board prepared through the above process is tested according to GB / T 17657-2013 "Test methods of physical and mechanical properties of wood-based panels and laminated veneer lumber", and the test results are as follows:

[0032]

[0033] Example 2

[0034] A manufacturing process of a soybean meal modified adhesive formaldehyde-free flake board with a thickness of 18mm, comprising the following steps:

[0035] 1. Wood material slicing→flaking→flakes drying (flakes moisture content after drying is about 2.0%)→screening;

[0036] 2. Surface layer flakes and core layer flakes are respectively treated with modified soybean meal adhesive: the surface layer flakes are added with 5% of modified soybean meal adhesive, 2.5% of MDI, 1% of tackifier and 0.8% of emulsified paraffin relative to the absolute dry flakes of the surface layer through a glue application system; the core layer flakes are added with 3% of MDI relative to the absolute dry flakes of the core layer through the glue application system;

[0037] 3. The moisture content of the surface layer flakes after glue application is about 17%, and the moisture content of the core layer flakes is about 4%;

[0038] 4. The lower surface layer+core layer+upper surface layer are respectively layered and laid through a laying system, and the board is prepared after pre-pressing and hot pressing, the hot pressing factor is 6 s / mm, and the hot pressing temperature is 230°C.

[0039] The performance of the 18mm flake board prepared through the above production process is tested according to GB / T 17657-2013 "Test methods of physical and mechanical properties of wood-based panels and laminated veneer lumber", and the test results are as follows:

[0040]

[0041] The above merely illustrates the embodiments of the present application, and is not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation, or direct or indirect application in other related technical fields, made according to the present application, are also included in the patent protection scope of the present application.

Claims

1. A process for manufacturing formaldehyde-free particleboard with soybean meal modified adhesive, comprising wood chipping → flaking → particle drying → screening → glue mixing and applying → paving → pre-pressing → hot pressing → trimming → cooling → tempering → sanding → inspection and grading → packaging and warehousing, characterized by: In the drying step, the moisture content of the dried wood chips is 2.0-3.0%; In the glue adjustment and application step, the surface and core layers are layered glued, including the application of adhesive, tackifier, and waterproofing agent on the surface layer, and the application of adhesive on the core layer. The adhesive on the surface layer is a mixture of soybean meal-modified adhesive and MDI, and the adhesive on the core layer is MDI. The application amount of each component is calculated according to the mass ratio of the absolute dry component to the absolute dry wood shavings of the corresponding layer.

2. The process for producing the soybean meal modified adhesive formaldehyde-free particleboard according to claim 1, wherein: In the surface layer, the soybean meal modified adhesive is added in an amount of 2-6%, and the amount of MDI is added in an amount of 0.3-3.5%.

3. The process for producing the soybean meal modified adhesive formaldehyde-free particleboard according to claim 2, wherein: The surface soybean meal modified adhesive and MDI are sprayed simultaneously through separate pipes and are uniformly mixed with the surface wood chips.

4. The process for producing the soybean meal modified adhesive formaldehyde-free particleboard according to claim 1, wherein: The thickener is one or more of polyvinyl alcohol solution, polyvinyl acetate, acrylate, carboxymethyl cellulose, and carrageenan, and the added amount is 0.2-2%.

5. The process for producing the soybean meal modified adhesive formaldehyde-free particleboard according to claim 4, wherein: The viscosity enhancer is polyvinyl alcohol solution.

6. The process for producing the soybean meal modified adhesive formaldehyde-free particleboard according to claim 1, wherein: The waterproofing agent is emulsified paraffin, and the addition amount is 0.5~1.5%.

7. The process for producing the soybean meal modified adhesive formaldehyde-free particleboard according to claim 1, wherein: The added amount of the core layer adhesive MDI is 0.5-4%, and the core layer shavings are evenly mixed through the core layer sizing system.

8. The process for producing the soybean meal modified adhesive formaldehyde-free particleboard according to claim 1, wherein: In the paving step, the moisture content of the wood chips after surface gluing is 15-18%.

9. The process for producing the soybean meal modified adhesive formaldehyde-free particleboard according to claim 1, wherein: In the paving step, the moisture content of the wood chips after the core layer is sizing is 4-7%.

10. The process for producing formaldehyde-free particleboard with soybean meal modified adhesive according to claim 1, characterized in that: In the slab hot pressing step, the hot pressing temperature is 200-240° C., the hot pressing pressure is 0-3.5 MPa, and the hot pressing factor is 6-10 s / mm.

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