Production process of low-odor fiberboard

Abstract

The invention belongs to the technical field of artificial boards, and relates to a production process of a low-odor fiberboard, which comprises the steps of wood storage, wood peeling, chipping, screening, water washing, pre-cooking, cooking, hot grinding, sizing, fiber drying, paving, pre-pressing, hot pressing, cooling, sanding, curing, inspection and grading, and packaging and warehousing. Wherein in the sizing process, an adhesive is an isocyanate adhesive, the addition mode is that the isocyanate adhesive is uniformly sprayed on the surface of the fiber at the position 2-3 m away from an outlet of a blow-off pipe, and the application amount is 40-70 kg / m; in the fiber drying process, the drying temperature is increased by 2-3 DEG C compared with the temperature of using urea resin. Poplar or eucalyptus is used as a wood raw material, isocyanate is used as an adhesive, a specific production process is adopted, the produced fiberboard is a low-odor fiberboard, according to LY / T 3236-2020'artificial board and product odor grading and evaluation method thereof ', the odor grade is smaller than or equal to 2 grade, and the problem of peculiar smell of the fiberboard is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of artificial boards, relates to the production of fiberboards, and particularly relates to a production process of low-odor fiberboards. Background Art

[0002] With the development of social economy, people have a higher level of pursuit for the quality of life, and the air quality issue has received widespread attention. According to research, due to the poor indoor air circulation, there are many volatile organic compounds (VOCs) in the indoor air, and the concentration of some VOCs can be more than 3 times higher than that of outdoor air. Many VOCs are odor substances. People who are in an environment with high concentration of odor substances for a long time will cause a series of problems such as lack of concentration, difficulty falling asleep, and mood swings. China is a major producer and consumer of artificial boards in the world. Fiberboard is one of the three major types of artificial boards. Due to its good physical and mechanical properties and processing properties, it is widely used in building decoration, furniture, flooring, doors and windows, and packaging materials. However, the VOCs and odor problems generated by wooden furniture made of artificial boards such as fiberboard have an increasing impact on people. For some newly decorated rooms, even if the VOCs test is qualified, consumers will still complain about odor. This is because some VOCs components have a very low odor threshold and still have a strong irritating odor at very low concentrations. Due to the large amount of indoor wooden furniture used and the large exposure area of ​​wooden furniture, it has become the main source of indoor air pollution. Therefore, research and solutions to the VOCs and odor problems of fiberboard and other artificial board products are of great significance to improving the environmental performance of wooden furniture, protecting people's physical and mental health, and improving the quality of life.

[0003] Based on the above situation, the present invention discloses a production process of low-odor fiberboard. According to the test of LY / T3236-2020 "Odor Grading and Evaluation Method of Artificial Boards and Their Products", the odor level is ≤ level 2, which can be used for interior decoration to solve the problem of odor of fiberboard. Summary of the invention

[0004] In order to solve the problem of odor of fiberboard, the purpose of the present invention is to disclose a low-odor fiberboard production process.

[0005] Technical Solution

[0006] A production process of low-odor fiberboard includes wood storage → wood peeling → chipping → screening → water washing → pre-cooking → cooking → hot grinding → gluing → fiber drying → laying → pre-pressing → hot pressing → cooling → sanding → curing → inspection and grading → packaging and warehousing, wherein:

[0007] In the wood storage process, the wood is poplar or eucalyptus stored in a yard for 8 to 12 months, preferably 10 months;

[0008] In the wood peeling process, wood stored in a yard at a height of more than 1 m from the ground is selected;

[0009] In the water washing process, fresh water is used for 2 to 5 days;

[0010] In the sizing process, the adhesive is an isocyanate adhesive, which is added by spraying it evenly onto the fiber surface at a distance of 2 to 3 m, preferably 1 m, from the outlet of the spray pipe. The application amount is 40 to 70 kg / m 3 , preferably 50kg / m 3 ;

[0011] In the fiber drying process, the drying temperature is 2 to 3°C higher than that of using urea-formaldehyde resin;

[0012] In the hot pressing process, the continuous press adopts five-stage temperature and pressure zone control, the temperature of the five zones is 5-10°C lower than that of urea-formaldehyde resin, preferably 8°C, and the press speed is reduced by 10-20%, preferably 15%, compared with that of urea-formaldehyde resin.

[0013] According to a preferred disclosed example of the present invention, in the sizing process, the isocyanate adhesive is stored and transported in pipelines for heat preservation, the storage tank temperature is maintained at 40-60°C, preferably 50°C, two intermediate storage tanks are arranged between the storage tank and the application outlet, and the intermediate storage tanks are provided with a heat preservation system, and the temperature is maintained at 40-60°C, preferably 50°C.

[0014] The isocyanate adhesive of the present invention is a mixture of isocyanate with a functionality of 2.6 to 2.7 and diphenylmethane diisocyanate, and is a light brown liquid at room temperature. The specific indicators are as follows: viscosity (25°C) is 150 to 250 mPa·s, isocyanate content (-NCO) is 30.5 to 32.0%, and density (25°C) is 1.220 to 1.250 g / cm 3 , acidity ≤0.030%, hydrolyzed chlorine ≤0.20%, iron ≤20μg / g.

[0015] In a preferred embodiment of the present invention, in order to prevent the slab from sticking to the hot press steel belt, before the slab enters the hot press, the upper and lower steel belt surfaces are sprayed with a release agent 30 to 60 minutes in advance, preferably 45 minutes in advance, with a spraying amount of 10 to 20 g / m 2 , preferably 15g / m 2 .

[0016] According to a preferred embodiment of the present invention, in the curing process, the sanded fiberboard is cured in a balancing room for 3 to 6 months, the temperature of the balancing room is 35 to 40° C., and the relative humidity is 60 to 70%.

[0017] The present invention aims at the odor problem existing in ordinary fiberboards, and uses a single tree species of poplar or eucalyptus as the wood raw material. The single tree species solves the problem of complex and changeable VOCs components of wood, so that the type of odor can be stably controlled; the poplar is stored in the yard for 8 to 12 months, during which the VOCs components in the poplar or eucalyptus are greatly reduced, solving the problem of strong odor intensity of the wood raw material; the poplar or eucalyptus that is more than 1m away from the ground in the yard is selected, and rotten wood is removed, solving the odor caused by decay during the raw material stacking process; fresh water is used in the washing process for 2 to 5 days, avoiding the problem of strong odor of wood chips caused by the enrichment of wood VOCs components in water; isocyanate adhesive is used as adhesive, Because isocyanate has good bonding properties, it solves the problem of poor physical and mechanical properties of wood boards caused by long storage time. The addition method is 2 to 3 meters away from the outlet of the spray pipe, which greatly reduces the risk of pre-curing of isocyanate adhesive in the pipeline and clogging the pipeline; the drying temperature is 2 to 3°C higher than that of ordinary fiberboard, which is more conducive to the release of VOCs components in the fiber; the hot pressing process adopts a low temperature and long time method, which not only greatly reduces the changes in wood components caused by high temperature and the generation of new odorous substances, but also allows the board to be fully exhausted in the press, reducing the probability of explosion; the long-term curing method is adopted to promote the release of VOCs substances in the board and effectively reduce the odor level of the fiberboard.

[0018] Beneficial Effects

[0019] The present invention can produce low-odor fiberboard only by selecting wood and optimizing the production process, which is more environmentally friendly and economical than adding deodorants and other technical solutions. The present invention uses poplar or eucalyptus as wood raw materials, uses isocyanate as adhesive, and adopts a specific production process. The fiberboard produced is a low-odor fiberboard. According to the test of LY / T 3236-2020 "Odor Classification and Evaluation Method of Artificial Boards and Their Products", the odor level is ≤ 2, which solves the odor problem of fiberboard. DETAILED DESCRIPTION

[0020] 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.

[0021] Example 1

[0022] A 10mm low-odor fiberboard production process comprises the following steps: wood storage → wood peeling → chipping → screening → water washing → pre-cooking → cooking → hot grinding → gluing → fiber drying → laying → pre-pressing → hot pressing → cooling → sanding → curing → inspection and grading → packaging and warehousing, to obtain a finished board, wherein:

[0023] The timber storage, the timber species is poplar, the poplar is stored in the yard for 8 months;

[0024] In the wood peeling process, poplar wood is selected from a yard that is more than 1m above the ground;

[0025] In the water washing process, fresh water is used for 2 days;

[0026] In the sizing process, the adhesive added is isocyanate adhesive, which is added by spraying it evenly on the fiber surface at a distance of 2 to 3 meters from the outlet of the spray pipe. The amount of isocyanate adhesive applied is 50 kg / m 3 ; The isocyanate adhesive is stored and transported in pipelines under insulation treatment, and the storage tank temperature is maintained at 45°C. Two intermediate storage tanks are set between the storage tank and the application outlet. The intermediate storage tanks are equipped with an insulation system and the temperature is maintained at 45°C.

[0027] In the fiber drying process, the drying temperature is 178-180°C, which is 2-3°C higher than that of urea-formaldehyde resin.

[0028] In the hot pressing process, the continuous press adopts five-stage temperature and pressure zone control, the temperature of the five zones is 5-10°C lower than that of urea-formaldehyde resin, and the press speed is reduced by 10-20% compared with the urea-formaldehyde resin process. The temperature of zone one is 205-210°C, the temperature of zone two is 200-205°C, the temperature of zone three is 195-200°C, and the press speed is 340-360 mm / s.

[0029] In the curing process, the sanded fiberboard is cured in a balancing room for 3 months, and the temperature of the balancing room is 40° C. and the relative humidity is 65%.

[0030] To prevent the slab from sticking to the hot press steel belt, the upper and lower steel belt surfaces were sprayed with a release agent 30 minutes in advance before the slab entered the hot press. The release agent was 3703 produced by Germany's WASH, with a spraying amount of 20g / m 2 .

[0031] The test data of the finished board is shown in Table 1.

[0032] Table 1 Test data of finished board

[0033]

[0034] Example 2

[0035] A 10mm low-odor fiberboard production process includes the following steps: wood storage → wood peeling → chipping → screening → water washing → pre-cooking → cooking → hot grinding → gluing → fiber drying → laying → pre-pressing → hot pressing → cooling → sanding → curing → inspection and grading → packaging and warehousing, to obtain a finished board II, wherein:

[0036] In the wood storage process, the wood species is eucalyptus, and the eucalyptus is stored in the yard for 10 months;

[0037] In the wood peeling process, eucalyptus wood is selected from a yard more than 1m above the ground;

[0038] In the water washing process, fresh water is used for 3 days;

[0039] In the sizing process, the adhesive added is isocyanate adhesive, which is added by spraying it evenly on the fiber surface at a distance of 2 to 3 meters from the outlet of the spray pipe. The amount of isocyanate adhesive applied is 60 kg / m 3 ; The isocyanate adhesive is stored and transported in pipelines under insulation treatment, and the storage tank temperature is maintained at 45°C. Two intermediate storage tanks are set between the storage tank and the application outlet. The intermediate storage tanks are equipped with an insulation system and the temperature is maintained at 45°C.

[0040] In the fiber drying process, the drying temperature is 178-180°C, which is 2-3°C higher than that of urea-formaldehyde resin.

[0041] In the hot pressing process, the continuous press adopts five-stage temperature and pressure zone control, the temperature of the five zones is 5-10°C lower than that of urea-formaldehyde resin, and the press speed is reduced by 10-20% compared with the urea-formaldehyde resin process. The temperature of zone one is 205-210°C, the temperature of zone two is 200-205°C, the temperature of zone three is 195-200°C, and the press speed is 320-350 mm / s.

[0042] In the curing process, the sanded fiberboard is cured in a balancing room for 6 months, and the temperature of the balancing room is 40° C. and the relative humidity is 65%.

[0043] To prevent the slab from sticking to the hot press steel belt, the upper and lower steel belt surfaces were sprayed with a release agent 60 minutes in advance before the slab entered the hot press. The release agent was 3703 produced by Germany's WASH, with a spraying amount of 20g / m 2 .

[0044] The test data of the finished plate 2 is shown in Table 2.

[0045] Table 2 Finished board second test data

[0046]

[0047] 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 production process of low-odor fiberboard, including wood storage → wood peeling → chipping → screening → water washing → pre-cooking → cooking → hot grinding → gluing → fiber drying → laying → pre-pressing → hot pressing → cooling → sanding → curing → inspection and grading → packaging and warehousing, characterized in that: In the wood storage process, the wood is poplar or eucalyptus stored in a yard for 8 to 12 months; In the wood peeling process, wood stored in a yard at a height of more than 1 m from the ground is selected; In the water washing process, fresh water is used for 2 to 5 days; In the sizing process, the adhesive is an isocyanate adhesive, which is added by spraying it evenly onto the fiber surface at a distance of 2 to 3 meters from the outlet of the spray pipe, and the applied amount is 40 to 70 kg / m³; In the fiber drying process, the drying temperature is 2 to 3°C higher than that of using urea-formaldehyde resin; In the hot pressing process, the continuous press adopts five-stage temperature and pressure zone control, the temperature of the five zones is 5-10°C lower than that of using urea-formaldehyde resin, and the press speed is reduced by 10-20% compared with that of using urea-formaldehyde resin.

2. The production process of low-odor fiberboard according to claim 1, characterized in that: In the wood storage process, the wood is poplar or eucalyptus stored in a yard for 10 months.

3. The production process of low-odor fiberboard according to claim 1, characterized in that: In the sizing process, the adhesive is an isocyanate adhesive, and the adding method is to evenly spray it onto the fiber surface at a distance of 1 m from the outlet of the spray pipe, and the applied amount is 50 kg / m³.

4. The production process of low-odor fiberboard according to claim 1, characterized in that: In the gluing process, the isocyanate adhesive is stored and transported in pipelines under insulation, the storage tank temperature is maintained at 40-60°C, two intermediate storage tanks are arranged between the storage tank and the application outlet, and the intermediate storage tanks are provided with an insulation system, and the temperature is maintained at 40-60°C.

5. The production process of low-odor fiberboard according to claim 4 is characterized in that: In the gluing process, the isocyanate adhesive is stored and transported in pipelines under insulation, the storage tank temperature is maintained at 50°C, two intermediate storage tanks are arranged between the storage tank and the application outlet, and the intermediate storage tanks are provided with an insulation system, and the temperature is maintained at 50°C.

6. The production process of low-odor fiberboard according to claim 1, characterized in that: The isocyanate adhesive is a mixture of isocyanate with a functionality of 2.6 to 2.7 and diphenylmethane diisocyanate.

7. The production process of low-odor fiberboard according to claim 1, characterized in that: To prevent the slab from sticking to the hot press steel belt, spray the release agent on the upper and lower steel belt surfaces 30 to 60 minutes in advance before the slab enters the hot press, with a spraying amount of 10 to 20 g / m 2 .

8. The production process of low-odor fiberboard according to claim 7, characterized in that: Before the slab enters the hot press, the upper and lower steel strip surfaces are sprayed with release agent 45 minutes in advance, with a spraying amount of 15 g / m 2 .

9. The production process of low-odor fiberboard according to claim 1, characterized in that: In the hot pressing process, the temperatures of the five zones are 8° C. lower than those using urea-formaldehyde resin, and the press speed is reduced by 15% compared with that using urea-formaldehyde resin.

10. The production process of low-odor fiberboard according to claim 1, characterized in that: In the curing process, the sanded fiberboard is cured in a balancing room for 3 to 6 months, the temperature of the balancing room is 35 to 40° C., and the relative humidity is 60 to 70%.

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