Manufacturing process of ENF-grade shaving board made of rubber wood

Abstract

The invention belongs to the technical field of wood processing, and relates to a rubber wood ENF-grade shaving board manufacturing process which comprises the steps of rubber wood chipping, flaking, wood shaving drying, screening, glue and waterproof agent mixing and applying, paving, pre-pressing, hot pressing, edge cutting, cooling, hardening and tempering, sanding, inspection and grading, and packaging and warehousing. Surface layer and core layer layered sizing is adopted, surface layer adhesives are acrylate adhesives, MDI and auxiliaries, core layer adhesives are MUF adhesives, MDI and auxiliaries, and the sizing amount is calculated according to the mass ratio of absolute dry glue to absolute dry wood shavings. The acrylic ester adhesive and the MDI do not contain formaldehyde, the MUF adhesive is low-formaldehyde MUF resin, on the basis that the manufactured shaving board meets the mechanical property index, the formaldehyde emission can reach the highest classification standard ENF level, and batch continuous production can be achieved; the assistant can reduce the moisture absorption of the rubber wood, effectively improve the mildew resistance, corrosion resistance and worm damage resistance of the wood, and prolong the service life of the wood.

Description

Technical Field

[0001] The invention belongs to the technical field of wood processing, relates to particleboard, and particularly relates to an E-type particleboard made of rubber wood. NF The manufacturing process of grade particleboard. Background Art

[0002] Rubber trees are common economic trees. After a certain age, they are no longer suitable for rubber production. Every year, some old and sick rubber trees need to be cut down. In the past, the straight trunks of the felled rubber trees were sawn into general materials such as laminated timber, while the branches, small-diameter timber and processing residues of rubber wood were often wasted.

[0003] These rubber wood wastes are actually used to make particleboards to improve their utilization rate. Rubberwood has uniform density, hard texture, and excellent physical and mechanical properties. However, due to the high content of starch, sugar, and protein in rubberwood, if it is directly used to make particleboards, the finished board will easily change color, mold, rot, and be eaten by insects. In addition, natural rubberwood is easy to absorb moisture, so many problems will arise during use. Summary of the invention

[0004] In order to better utilize rubber wood, the present invention discloses an E NF The manufacturing process of grade particleboard.

[0005] Technical Solution

[0006] A rubber wood NF The manufacturing process of grade particleboard includes rubber wood chipping → shavings → drying of wood particles → screening → applying glue and waterproofing agent → paving → pre-pressing → hot pressing → trimming → cooling → tempering → sanding → inspection and grading → packaging and warehousing, including:

[0007] In the drying step, the moisture content of the dried wood chips is 2.0-3.0%;

[0008] In the screening step, the dried wood shavings are screened into surface fine wood shavings and core coarse wood shavings, the surface wood shavings are 20-100 mesh, the core wood shavings are 0.5-2 mm thick, 20-80 mm long, and 5-15 mm wide; the rubber particles and other impurities after the rubber residues in the surface and core materials are removed by air selection;

[0009] In the step of applying glue and waterproofing agent, the surface and core layers are applied in layers, the surface adhesive is an acrylic adhesive, MDI and an additive, the core layer adhesive is a MUF adhesive, MDI and an additive, and the amount of glue applied is calculated according to the mass ratio of absolute dry glue to absolute dry wood shavings;

[0010] In the paving step, the moisture content of the wood chips after the surface layer is glued is 12-18%, and the moisture content of the wood chips after the core layer is glued is 4-7%;

[0011] 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.

[0012] According to a preferred disclosed example of the present invention, when the surface adhesive is applied, the application amount of the acrylic adhesive is 0.5-4%, preferably 2%, and the application amount of the MDI is 0.3-3.5%, preferably 2%; the surface acrylic adhesive and MDI are uniformly stirred with the surface wood chips through the surface adhesive application system, and the acrylic adhesive and MDI are sprayed using one pipeline each.

[0013] According to a preferred disclosed example of the present invention, when the core layer adhesive is applied, the application amount of MUF adhesive is 1-6%, preferably 3%, and the application amount of MDI is 0.5-4%, preferably 2%; the core layer MUF adhesive and MDI are uniformly stirred with the core layer shavings through the core layer adhesive application system, and the MUF adhesive and MDI are sprayed using one pipeline each.

[0014] In a preferred disclosed example of the present invention, the auxiliary agent is one or more of furfuryl alcohol, acetic anhydride, maleic anhydride, and octyl isothiazolinone, preferably acetic anhydride, and the added amount is 0.05-1.5% of the absolute dry wood shavings, preferably 1%; when applied, the type of the surface layer auxiliary agent is the same as that of the core layer auxiliary agent.

[0015] In a preferred embodiment of the present invention, the auxiliary agent is diluted with water and then sprayed, or mixed with MUF resin and then sprayed.

[0016] According to a preferred embodiment of the present invention, in the step of applying glue and waterproofing agent, the amount of emulsified paraffin as the surface waterproofing agent is 0.3-0.8% relative to the absolute dry surface wood shavings, preferably 0.5%; the amount of emulsified paraffin as the core waterproofing agent is 0.3-0.8% relative to the absolute dry core wood shavings, preferably 0.5%.

[0017] The present invention makes the following improvements on the problems existing in the use of rubber wood for particleboards: firstly, there will be residual emulsion in the rubber wood, and some rubber particles will be mixed in the wood particles after drying, and the rubber particles will affect the quality of the particleboard to a certain extent, and the rubber particles can be screened out to ensure the stability of the quality of the particleboard; secondly, the particleboard made of rubber wood is easy to change color, mold, rot and be eaten by insects, and the natural rubber wood is easy to absorb moisture, and the use of additives can inhibit moisture from entering the interior of the wood, reduce the moisture absorption of the rubber wood, effectively improve the wood's mildew, anti-corrosion and anti-insect properties, and extend the service life of the wood; finally, the rubber wood has a hard texture, and the use of MDI will result in poor surface processability, and the use of an acrylic adhesive on the surface can make the surface of the particleboard easier to process.

[0018] The MUF resin used in the present invention is obtained from Daya Wood-Based Panel Group Co., Ltd., with a molar ratio of 0.77, pH 8.5-10, and a solid content of 55-63%; the acrylic ester adhesive is purchased from BASF AG, model acForm; and MDI is purchased from Wanhua Chemical Group Co., Ltd.

[0019] Beneficial Effects

[0020] The acrylic ester adhesive and MDI adopted in the present invention do not contain formaldehyde, the MUF adhesive is a low-formaldehyde MUF resin, and the production process is no different from that of an ordinary particle board using MDI, and no major changes are required to the production line. The prepared particle board can achieve the highest grading standard ENF level on the basis of meeting the mechanical performance index, and can achieve batch continuous production; the use of the auxiliary agent can reduce the moisture absorption of the rubber wood, effectively improve the mildew, anti-corrosion and anti-insect properties of the wood, and extend the service life of the wood; the rubber wood has a relatively hard texture, and the use of MDI will result in poor surface processability, and the use of the acrylic ester adhesive on the surface can make the surface of the particle board easier to process. DETAILED DESCRIPTION

[0021] The present invention is described in detail below in conjunction with the embodiments so that those skilled in the art can better understand the present invention, but the present invention is not limited to the following embodiments.

[0022] Example 1

[0023] A rubber wood NF The manufacturing process of grade particleboard, thickness 18mm, includes the following steps:

[0024] 1. Wood material → chipping → shavings → shavings drying (after drying, the moisture content of shavings is about 2.0%) → screening;

[0025] 2. The surface wood chips and the core wood chips were treated with glue respectively: 3% of acrylic adhesive, 1% of MDI, 0.3% of furfuryl alcohol, and 0.8% of emulsified paraffin were added to the surface wood chips through the glue application system relative to the surface dry wood chips; 1.5% of MUF adhesive, 2% of MDI, 0.3% of furfuryl alcohol, and 0.8% of emulsified paraffin were added to the core wood chips through the glue application system relative to the core dry wood chips;

[0026] 3. The moisture content of the surface shavings after sizing is about 14%, and the moisture content of the core shavings is about 5.5%;

[0027] 4. The lower surface layer + core layer + upper surface layer are laid in layers through the paving system, and the board is obtained after paving pre-pressing and hot pressing. The hot pressing factor is 6s / mm and the hot pressing temperature is 220℃.

[0028] The performance of the 18mm particleboard produced by the above production process was tested according to GB / T 17657-2013 "Test methods for physical and chemical properties of wood-based panels and veneer wood-based panels". The test results are as follows:

[0029]

[0030]

[0031] Example 2

[0032] A rubber wood NF The manufacturing process of grade particleboard, thickness 18mm, includes the following steps:

[0033] 1. Wood material → chipping → shavings → shavings drying (after drying, the moisture content of shavings is about 2.0%) → screening;

[0034] 2. The surface wood chips and the core wood chips are treated with glue respectively: 3% of acrylic adhesive, 1% of MDI, 0.5% of acetic anhydride, and 0.8% of emulsified paraffin are added to the surface wood chips through the glue application system relative to the surface dry wood chips; 3% of MUF adhesive, 1% of MDI, 0.5% of acetic anhydride, and 0.8% of emulsified paraffin are added to the core wood chips through the glue application system relative to the core dry wood chips;

[0035] 3. The moisture content of the surface shavings after sizing is about 16%, and the moisture content of the core shavings is about 4.5%;

[0036] 4. The lower surface layer + core layer + upper surface layer are laid in layers through the paving system, and the board is obtained after paving pre-pressing and hot pressing. The hot pressing factor is 6s / mm and the hot pressing temperature is 220℃.

[0037] The performance of the 18mm particleboard produced by the above production process was tested according to GB / T 17657-2013 "Test methods for physical and chemical properties of wood-based panels and veneer wood-based panels". The test results are as follows:

[0038]

[0039] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the specification of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A rubber wood NF The manufacturing process of grade particleboard includes rubber wood chipping → shaving → particle drying → screening → applying glue and waterproofing agent → paving → pre-pressing → hot pressing → trimming → cooling → quenching and tempering → sanding → inspection and grading → packaging and warehousing, which is characterized by: In the drying step, the moisture content of the dried wood chips is 2.0-3.0%; In the screening step, the dried wood shavings are screened into surface fine wood shavings and core coarse wood shavings, the surface wood shavings are 20-100 mesh, the core wood shavings are 0.5-2 mm thick, 20-80 mm long, and 5-15 mm wide; the rubber particles and other impurities after the rubber residues in the surface and core materials are removed by air selection; In the step of applying glue and waterproofing agent, the surface and core layers are applied in layers, the surface adhesive is an acrylic adhesive, MDI and an additive, the core layer adhesive is a MUF adhesive, MDI and an additive, and the amount of glue applied is calculated according to the mass ratio of absolute dry glue to absolute dry wood shavings; In the paving step, the moisture content of the wood chips after the surface layer is glued is 12-18%, and the moisture content of the wood chips after the core layer is glued is 4-7%; 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.

2. The E of rubber wood according to claim 1 NF The manufacturing process of grade particle board is characterized by: When applying the surface adhesive, the application amount of the acrylic adhesive is 0.5-4%, and the application amount of the MDI is 0.3-3.5%; the surface acrylic adhesive and MDI are evenly mixed with the surface wood chips through the surface gluing system, and the acrylic adhesive and MDI are sprayed using one pipe each.

3. The E of rubber wood according to claim 2 NF The manufacturing process of grade particle board is characterized by: When the surface adhesive is applied, the amount of the acrylic adhesive applied is 2%, and the amount of the MDI applied is 2%.

4. The E of rubber wood according to claim 1 NF The manufacturing process of grade particle board is characterized by: When applying the core layer adhesive, the application amount of MUF adhesive is 1-6%, and the application amount of MDI is 0.5-4%; the core layer MUF adhesive and MDI are evenly mixed with the core layer shavings through the core layer adhesive application system, and the MUF adhesive and MDI are sprayed using one pipeline each.

5. The E of rubber wood according to claim 4 NF The manufacturing process of grade particle board is characterized by: When the core layer adhesive is applied, the application amount of MUF adhesive is 3%, and the application amount of MDI is 2%.

6. The E of rubber wood according to claim 1 NF The manufacturing process of grade particle board is characterized by: In the step of adjusting the glue and waterproofing agent, the auxiliary agent is one or more of furfuryl alcohol, acetic anhydride, maleic anhydride, and octyl isothiazolinone, and the added amount is 0.05-1.5% of the absolute dry wood chips; when applying, the type of the surface layer auxiliary agent is the same as that of the core layer auxiliary agent.

7. The E of rubber wood according to claim 1 NF The manufacturing process of grade particle board is characterized by: In the step of adjusting the glue and waterproofing agent, the auxiliary agent is acetic anhydride.

8. The E of rubber wood according to claim 1 NF The manufacturing process of grade particle board is characterized by: In the step of adding glue and waterproofing agent, the amount of the auxiliary agent added is 1% of the absolutely dry wood chips.

9. The E of rubber wood according to claim 1 NF The manufacturing process of grade particle board is characterized by: The additive is diluted with water and then sprayed, or mixed with MUF resin and then sprayed.

10. The E of rubber wood according to claim 1 NF The manufacturing process of grade particle board is characterized by: In the step of applying glue and waterproofing agent, the amount of emulsified paraffin as surface waterproofing agent is 0.3-0.8% relative to the absolute dry surface wood shavings, preferably 0.5%; the amount of emulsified paraffin as core waterproofing agent is 0.3-0.8% relative to the absolute dry core wood shavings, preferably 0.5%.

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