CN116373063A - Low-formaldehyde ultrathin fiber board and preparation method thereof - Google Patents
Low-formaldehyde ultrathin fiber board and preparation method thereof Download PDFInfo
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- CN116373063A CN116373063A CN202310305352.7A CN202310305352A CN116373063A CN 116373063 A CN116373063 A CN 116373063A CN 202310305352 A CN202310305352 A CN 202310305352A CN 116373063 A CN116373063 A CN 116373063A
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- 239000011094 fiberboard Substances 0.000 title claims abstract description 46
- 238000002360 preparation method Methods 0.000 title claims abstract description 22
- WSFSSNUMVMOOMR-UHFFFAOYSA-N formaldehyde Substances O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 title claims description 15
- 239000000835 fiber Substances 0.000 claims abstract description 68
- 239000002023 wood Substances 0.000 claims abstract description 64
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 41
- 238000007731 hot pressing Methods 0.000 claims abstract description 34
- 238000000034 method Methods 0.000 claims abstract description 32
- 238000001035 drying Methods 0.000 claims abstract description 28
- 239000012188 paraffin wax Substances 0.000 claims abstract description 26
- 239000000853 adhesive Substances 0.000 claims abstract description 22
- 230000001070 adhesive effect Effects 0.000 claims abstract description 22
- 239000000463 material Substances 0.000 claims abstract description 20
- 229920001807 Urea-formaldehyde Polymers 0.000 claims abstract description 18
- GZCGUPFRVQAUEE-SLPGGIOYSA-N aldehydo-D-glucose Chemical compound OC[C@@H](O)[C@@H](O)[C@H](O)[C@@H](O)C=O GZCGUPFRVQAUEE-SLPGGIOYSA-N 0.000 claims abstract description 18
- 238000010025 steaming Methods 0.000 claims abstract description 15
- 238000000227 grinding Methods 0.000 claims abstract description 12
- 229920002522 Wood fibre Polymers 0.000 claims abstract description 11
- 239000002025 wood fiber Substances 0.000 claims abstract description 11
- 239000012752 auxiliary agent Substances 0.000 claims abstract description 8
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonia chloride Chemical group [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 claims description 24
- 230000008569 process Effects 0.000 claims description 23
- 239000007787 solid Substances 0.000 claims description 16
- 238000005406 washing Methods 0.000 claims description 15
- 239000003795 chemical substances by application Substances 0.000 claims description 13
- 235000019270 ammonium chloride Nutrition 0.000 claims description 12
- 238000010411 cooking Methods 0.000 claims description 9
- 238000003825 pressing Methods 0.000 claims description 6
- 238000004513 sizing Methods 0.000 claims description 4
- 238000007493 shaping process Methods 0.000 claims 1
- 238000005259 measurement Methods 0.000 description 7
- 238000003801 milling Methods 0.000 description 6
- 235000008331 Pinus X rigitaeda Nutrition 0.000 description 5
- 235000011613 Pinus brutia Nutrition 0.000 description 5
- 241000018646 Pinus brutia Species 0.000 description 5
- 238000001816 cooling Methods 0.000 description 5
- 238000000926 separation method Methods 0.000 description 5
- 238000009835 boiling Methods 0.000 description 4
- 238000001125 extrusion Methods 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 238000002156 mixing Methods 0.000 description 4
- 238000004806 packaging method and process Methods 0.000 description 4
- 239000007921 spray Substances 0.000 description 4
- 229920002678 cellulose Polymers 0.000 description 3
- 239000001913 cellulose Substances 0.000 description 3
- 239000002131 composite material Substances 0.000 description 3
- 230000018044 dehydration Effects 0.000 description 3
- 238000006297 dehydration reaction Methods 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 230000005855 radiation Effects 0.000 description 3
- 238000003860 storage Methods 0.000 description 3
- 229920002488 Hemicellulose Polymers 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 238000001739 density measurement Methods 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 239000013049 sediment Substances 0.000 description 2
- 238000003892 spreading Methods 0.000 description 2
- 230000007480 spreading Effects 0.000 description 2
- 230000003068 static effect Effects 0.000 description 2
- 108010010803 Gelatin Proteins 0.000 description 1
- 241000219000 Populus Species 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 150000001299 aldehydes Chemical class 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000003763 carbonization Methods 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000005056 compaction Methods 0.000 description 1
- 230000000536 complexating effect Effects 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000005034 decoration Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000029087 digestion Effects 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000007667 floating Methods 0.000 description 1
- 229920000159 gelatin Polymers 0.000 description 1
- 239000008273 gelatin Substances 0.000 description 1
- 235000019322 gelatine Nutrition 0.000 description 1
- 235000011852 gelatine desserts Nutrition 0.000 description 1
- 239000003292 glue Substances 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000010335 hydrothermal treatment Methods 0.000 description 1
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 229920005610 lignin Polymers 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 238000007885 magnetic separation Methods 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 239000005022 packaging material Substances 0.000 description 1
- 239000000123 paper Substances 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 239000012466 permeate Substances 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 238000011002 quantification Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27N—MANUFACTURE BY DRY PROCESSES OF ARTICLES, WITH OR WITHOUT ORGANIC BINDING AGENTS, MADE FROM PARTICLES OR FIBRES CONSISTING OF WOOD OR OTHER LIGNOCELLULOSIC OR LIKE ORGANIC MATERIAL
- B27N3/00—Manufacture of substantially flat articles, e.g. boards, from particles or fibres
- B27N3/04—Manufacture of substantially flat articles, e.g. boards, from particles or fibres from fibres
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27N—MANUFACTURE BY DRY PROCESSES OF ARTICLES, WITH OR WITHOUT ORGANIC BINDING AGENTS, MADE FROM PARTICLES OR FIBRES CONSISTING OF WOOD OR OTHER LIGNOCELLULOSIC OR LIKE ORGANIC MATERIAL
- B27N3/00—Manufacture of substantially flat articles, e.g. boards, from particles or fibres
- B27N3/08—Moulding or pressing
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21B—FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
- D21B1/00—Fibrous raw materials or their mechanical treatment
- D21B1/04—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres
- D21B1/12—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres by wet methods, by the use of steam
- D21B1/14—Disintegrating in mills
- D21B1/16—Disintegrating in mills in the presence of chemical agents
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C3/00—Pulping cellulose-containing materials
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C5/00—Other processes for obtaining cellulose, e.g. cooking cotton linters ; Processes characterised by the choice of cellulose-containing starting materials
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/91—Use of waste materials as fillers for mortars or concrete
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Wood Science & Technology (AREA)
- Manufacturing & Machinery (AREA)
- Forests & Forestry (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Mechanical Engineering (AREA)
- Dry Formation Of Fiberboard And The Like (AREA)
Abstract
Provides a low-aldehyde ultrathin fiber board and a preparation method thereof, which can obtain the fiber board with good performance, the thickness is as thin as 0.8mm, and the density is as high as 0.9g/m 3 The ultrathin high-density fiberboard. The preparation method comprises the following steps: steaming the qualified wood chips, wherein the steaming pressure is 7.5 bar-8.0 bar, the steaming temperature is 160-165 ℃, and the steaming time is 3.5-4.0 min; adding melted 58# fully refined paraffin into the steamed wood chips and carrying out hot grinding to obtain 50-100 mesh wood fibers; uniformly applying urea-formaldehyde resin adhesive and an auxiliary agent on the surface of the wood fiber in a drying pipeline; drying the glued wood fiber to obtain the wood fiber with the water content of 6.0-6.5%Paving materials; paving the paving material into a continuous slab band, setting the thickness of the target plate to be 0.8mm and the density of the fiber plate to be 1050Kg/m 3 The method comprises the steps of carrying out a first treatment on the surface of the And conveying the slab band to a hot press for hot pressing, wherein the hot press is provided with four continuous pressure sections, the hot pressing temperature of the four pressure sections is gradually reduced according to the advancing direction of the slab band, and the hot pressing pressure of at least three later pressure sections is gradually increased.
Description
Technical Field
The invention relates to the field of manufacturing of ultrathin fiber plates, in particular to a low-formaldehyde ultrathin fiber plate and a preparation method thereof.
Background
On one hand, the ultrathin fiber board can be used as a facing material to replace the existing technical wood and poplar decorative veneers to produce super-flat, skin-feel, highlight and other high-grade furniture, and solves the problems of carbonization, unevenness, easy cracking and the like of the furniture after the surface decoration; on the other hand, the composite floor can be used as a balance facing of a high-grade solid wood composite floor and has the characteristics of high strength, deformation resistance, high dimensional stability and the like; in addition, the functional ultrathin fiber board can also be used for green and environment-friendly packaging materials of high-grade gift boxes and the like, and is more green and environment-friendly than common paper materials. At present, the research on ultrathin fiber boards is seen in other countries, china has been in the front of the world in the field of ultrathin fiber board production process and equipment, the manufacturing production capacity of ultrathin fiber boards with the minimum thickness of 1.0mm is achieved, but ultrathin fiber boards with the thickness of less than 1mm, such as 0.8mm, are not disclosed in the related art, and the 0.8mm ultrathin fiber boards have great industrial demands in the aspects of product application and new field expansion.
Disclosure of Invention
The invention has been developed in view of the above technical problems, and has an object to provide a sheet having a thickness of 0.8mm and a density of 0.9g/m 3 The ultrathin high-density fiberboard and the preparation method thereof obtain the low-formaldehyde ultrathin fiberboard with good performance.
The invention provides the following technical scheme:
1. the preparation method of the low-formaldehyde ultrathin fiber board comprises the following steps:
and (3) cooking: steaming the qualified wood chips, wherein the steaming pressure is 7.5 bar-8.0 bar, the steaming temperature is 160-165 ℃, and the steaming time is 3.5-4.0 min;
and (3) heat grinding: adding melted 58# fully refined paraffin into the steamed wood chips and carrying out hot grinding to obtain 50-100 mesh wood fibers;
sizing: uniformly applying urea-formaldehyde resin adhesive and an auxiliary agent on the surface of the wood fiber in a drying pipeline;
and (3) drying: drying the glued wood fibers to obtain a pavement material with the water content of 6.0-6.5%;
paving: paving the paving material into a continuous slab band, setting the thickness of the target plate to be 0.8mm and the density of the fiber plate to be 1050Kg/m 3 ；
And (3) hot pressing: the slab band is sent to a hot press for hot pressing, the hot press is provided with four continuous pressure zones, the hot pressing temperature of the four pressure zones is gradually reduced according to the advancing direction of the slab band, and the hot pressing pressure of at least the three pressure zones is gradually increased,
wherein, the entrance of the slab is set to be 6.8mm, and the slab band advancing direction is set as follows: the hot-pressing temperature in the first section is 175 ℃, the hot-pressing temperature in the second section is 165 ℃, the hot-pressing temperature in the third section is 140 ℃, and the hot-pressing temperature in the fourth section is 130 ℃; the hot pressing pressure of the first interval is 35 bar-50 bar, the hot pressing pressure of the second interval is 25 bar-55 bar, the hot pressing pressure of the third interval is 55 bar-80 bar, and the hot pressing pressure of the fourth interval is 120 bar-150 bar; the hot pressing speed was 105m/min.
Wherein the qualified wood chips are wood chips with the length of 5 cm-8 cm, the width of 5 cm-8 cm and the thickness of 1 cm-2 cm and the water content of 55% -65%.
Wherein, the preparation of the qualified wood chips comprises water washing treatment: washing and dehydrating the flakes with the length of 5 cm-8 cm, the width of 5 cm-8 cm and the thickness of 1 cm-2 cm, and controlling the water content of the wood chips to be 55% -65%;
wherein the preparation of the qualified wood chips further comprises preheating treatment: preheating the washed wood chips, and controlling the preheating temperature to be between 90 and 98 ℃.
Wherein, the preparation of the qualified wood chips further comprises a press forming treatment: and extruding the preheated wood chips by a reducing screw to form a wood plug.
Wherein the addition amount of the 58# full refined paraffin relative to the volume of the finished fiberboard is 8kg/m 3 ～10kg/m 3 。
Wherein the solid content of the urea-formaldehyde resin adhesive is 49-53%, and the application amount of the urea-formaldehyde resin adhesive is 11-13% relative to the weight of the absolute dry fiber.
Wherein the auxiliary agent comprises a curing agent and paraffin, the curing agent is ammonium chloride, and the addition amount of the curing agent is 0.40-0.50% relative to the weight of the absolute dry fiber; the solid content of paraffin is 100%, and the addition amount of the paraffin is 0.7-0.9% relative to the weight of the absolute dry fiber.
Wherein, still include pre-compaction before the autoclave treatment: pre-pressing the paved slab band, wherein the pre-pressing pressure is 95 bar-130 bar.
2. A low-formaldehyde ultrathin fiber sheet prepared by the preparation method.
Factors influencing the preparation of the 0.8mm ultrathin fiber board are mainly fiber hot milling quality, drying moisture content and hot pressing parameters. The size of the thermal grinding fiber and the hot pressing parameters influence the strength of the ultrathin fiber board, the drying moisture content influences whether the ultrathin fiber board explodes, the surface of the ultrathin fiber board with the too high moisture content is easy to bubble, and the upper surface and the lower surface of the ultrathin fiber board with the too low moisture content are easy to delaminate. The performance test of the 0.8mm ultrathin fiber board prepared by the process meets the requirement of the China forest industry Association T/CNFPIA 3007-2019 on ultrathin high-density fiber boards.
Detailed Description
Unless otherwise specified in the embodiments, the numerical range "A to B" means not less than A (not less than A) but not more than B (not less than B), and when normal temperature or room temperature is mentioned, it is usually between 22 and 25℃and, depending on the process, may be between 20 and 28 ℃. Some processes are generally considered to be performed at or above the ambient temperature when the temperature is limited.
In the practical industry, different fields have different understandings of normal temperature or room temperature, but in terms of implementation and application of patent law, the purpose of the invention should be achieved according to the application scope to be specific, and the invention is not limited to the narrow experience of a certain field. It will also be appreciated by those skilled in the art that when referring to the actual meaning of a certain temperature, the control of the temperature is not an absolute constant temperature, a certain degree of float will tend to occur, which in a certain scenario may be more than one degree, or even more, as long as experimental purposes can be achieved.
The defined temperature may be a temperature control input to the equipment used, the temperature at a point in practice being dependent on the particularities of the machine equipment and the circumstances at the time of the reaction. The defined temperature may also be the target of a person's instructions, and the actual control may involve a period of temperature change, even including a process of repeatedly floating up and down, for example, heating the reactor when a temperature below the defined temperature is detected, cooling the reactor when above the defined temperature, and maintaining the instructed temperature as a whole. In addition to temperature, processes will also occur in embodiments with respect to thickness, density or pressure, rate of process change, etc., the nature of which is understood with reference to the above-described temperature definition principles.
The embodiment provides a preparation process of an ultrathin fiberboard, wherein the ultrathin fiberboard refers to a fiberboard with the thickness of less than 1.5mm, in particular to a high-density fiberboard with the thickness of less than 1.5mm, and the requirement of high density refers to that the density is more than or equal to 0.8g/m 3 . According to the process, especially for preparing a material as thin as 0.8mm and having a density of up to 0.9g/m 3 The ultrathin high-density fiberboard.
In some studies, aldehyde-free ultrathin fiber sheets have been proposed, but the aldehyde-free adhesive suffers from the defect of high cost, and on the other hand, the addition of urea-formaldehyde resin adhesive in the preparation of fiber sheets tends to face the influence on the performance of fiber sheets. In contrast, the present invention employs a scheme for preparing ultra-thin fiberboard with low aldehyde release rate. According to the preparation scheme, the aim of thinner and higher density fiber board can be achieved, the mechanical property requirement can be met, and the preparation method particularly meets the multiple standard requirements in the ultra-thin high density fiber board of the China industry association of forest products T/CNFPIA 3007-2019.
The preparation process of the low-formaldehyde ultrathin fiber board provided by the invention will be described in detail in the embodiment, and corresponding limitations can be included in the claimed technical scheme according to the understanding of the person skilled in the art. The invention also requires the protection of the low-formaldehyde ultrathin fiber board product prepared by the process.
Planing:
the log material is flaked, and the technological requirement is that the length and the width of the log are 5 cm-8 cm and the thickness is 1 cm-2 cm. Flaking of log material can be performed using a flaker, but the invention is not limited to log and flaker, and in the examples, log material is verified by New Zealand radiation. The flaking method is not limited to direct flaking of wood, and can be matched with a chipper and a crusher for use. The shavings of the required process can also be purchased from the market.
Washing:
the flaking is sent to a washing machine, and the flaking directly enters a spiral dehydrator after coming out of the washing machine, and the spiral dehydrator can drain water to flow back to the washing section. The method can remove sediment, dirt and nonmetallic impurities attached to the wood chips by washing the wood chips, and can replace the magnetic separation process to a certain extent, thereby well reducing pollutants and sediments.
On the other hand, the water content of the wood chips can be improved or controlled by washing the wood chips. The water content of the wood chips is too high, long fibers are easy to obtain before hot milling, the long fibers are easy to warp, and are easy to gather and agglomerate during molding, so that interweaving and complexing among the fibers are not facilitated, and the paving quality of wet slabs is affected. The water content of the wood chips is too low, the wood chips are easy to soften and not permeate, the fiber separation is difficult, the fiber cutting probability is high, the coarse fibers and the superfine fibers are increased, and the fiber separation quality is reduced.
The water content of the wood chips can be controlled to 55% -65%, preferably 53% -62%, more preferably about 50% by the water washing and dewatering processes. The water washing procedure is favorable for adjusting water washing parameters, and the water content of the wood chips can be effectively controlled. In addition, mutual friction among fibers plays a leading role in hot grinding, millstone contact becomes a secondary factor, and excessive crushing and cutting of the fibers can be avoided by controlling the water content of the washed wood chips to be about 50%, so that the fiber separation quality is ensured.
Pretreatment:
as a preferred or alternative embodiment, the washed and dewatered accept chips may be pre-heat treated. Specifically, qualified wood chips are temporarily stored in a preheating buffer bin before entering a thermal mill through a closed conveyor belt, and the preheating temperature is controlled to be 90-98 ℃. The qualified wood chips refer to clean wood chips after cleaning, in particular to wood chips with the length and the width of the wood chips ranging from 5cm to 8cm, the thickness ranging from 1cm to 2cm and the water content ranging from 55% to 65%.
The plugs may also be formed by reducing screw extrusion before the chips are fed to the digester for softening treatment, as desired. It is worth mentioning that the too high water content of the wood chips can reduce the friction between the wood chips and the feeding screw, and the wood extrudes water when being compressed, and the water is equivalent to a lubricant, so that the slipping phenomenon is generated between the wood chips and the screw surface, and the formation of a wood plug is not facilitated. The water content of the wood chip is too low, so that the axial force of a feeding screw is increased, the abrasion of a bearing is accelerated, and the wood plug is not compact and is easy to cause reverse spraying.
And (3) cooking:
and feeding the pretreated or washed qualified wood chips into a vertical digester for digestion and softening treatment. When the fiber required by the 0.8mm ultrathin fiber board is prepared, the cooking pressure is 7.5 bar-8.0 bar, the temperature is 160-165 ℃, and the cooking treatment time is 3.5-4.0 min.
The wood is steamed and softened, water can be utilized to carry out swelling on a non-crystalline region of cellulose, hemicellulose and lignin, free volume space is provided for intense molecular movement, after the wood is subjected to hydrothermal treatment, a part of hemicellulose is easy to decompose and dissolve into a liquid state, free hydroxyl groups on molecular chains of an amorphous region of cellulose adsorb water, so that a water film in a cellulose gap is thickened, the inter-molecular distance is increased, the attractive force is reduced, and relative sliding is convenient to generate under the action of external force.
And (3) hot grinding:
feeding the steamed wood chips into a thermal mill, adding melted 58# fully refined paraffin into the thermal mill, and controlling the adding amount according to the volume of the finished fiber plate, wherein the adding amount is controlled to be 8-10 kg/m in the examples provided by the application 3 . The fiber raw material after being steamed is subjected to pressure and rotation of a thermal mill to obtain the wood fiber with 50-100 meshes. The hot milling time is not always strictly limited, but is preferably controlled to 2.8min to 3min. And delivering the qualified fibers into a drying pipeline.
The water content of the wood chips is homogenized by the hot grinding treatment, and the fiber separation efficiency and the fiber separation uniformity suitable for the subsequent process are obtained. The known separated fiber is a very complex physical mechanical and chemical conversion process, and because of the very complex theory, the research of the mechanism of the separated fiber is difficult to observe and simulate, and the quantification is difficult to carry out, but the consideration of good thermal grinding quality is an important factor of fiber board.
And (3) glue mixing and sizing:
the adhesive and the auxiliary agent are applied in a spray shape through respective metering pipelines, so that the adhesive and the auxiliary agent form an impact type stirring state with fiber flow in a drying pipeline, and the uniform distribution of materials on the surface of the fiber is ensured. The gelatin adhesive adopts urea-formaldehyde resin adhesive, the solid content is 49-53%, preferably 51%, and the application amount is 11-13%, preferably 12.5% relative to the weight of absolute dry fiber. The auxiliary agent comprises a curing agent and paraffin wax.
The type of the curing agent is not limited, and one skilled in the art can understand that the curing agent can be properly selected, and specifically, a single-component curing agent, a multi-component curing agent, or a composite curing agent can be selected, and the specific gravity addition amount of the curing agent relative to the absolute dry fiber is 0.40% -0.50%, preferably 0.45%, and ammonium chloride is preferably used in the embodiment provided by the invention. The paraffin wax has a solid content of 100% and an addition amount of 0.7 to 0.9%, preferably 0.8%, based on the dry fiber weight.
And (3) drying:
the fiber is hot ground and sized, so that the water content of the fiber reaches 58% -62%, the water in the fiber is required to be evaporated by converting a liquid phase into a gas phase through a drying system, the temperature of an inlet pipeline of the drying system is controlled to be 100 ℃ -110 ℃, the temperature of an outlet pipeline is controlled to be 55 ℃ -68 ℃, and the water content of the final fiber is controlled to be 6.0% -6.5%. The drying moisture content influences whether the ultrathin fiber board explodes, the surface of the ultrathin fiber board with the too high moisture content is easy to bubble, and the upper surface and the lower surface of the ultrathin fiber board with the too low moisture content are easy to delaminate.
Paving:
spreading the fibers into fibers by a spreading and forming machineContinuous slab band with target sheet thickness of 0.8mm, fiber board density of 1050Kg/m 3 The width of the slab band is 1250mm to control the paving process. According to the density requirement, the paving machine performs blanking through a spiral blanking device, and the paving height deviation is +/-3 mm.
Prepressing:
the paved slab band is conveyed to a preformer through a conveying belt, and the pre-pressing pressure is set to be 95 bar-130 bar.
Hot pressing:
the pre-pressed slab band is conveyed to a hot press, the inlet of the slab band is set to be 6.8mm, the hot press is divided into 4 continuous pressure zones, and the hot press temperature of 1 zone is set to 175 ℃, the hot press temperature of 2 zones is set to 165 ℃, the hot press temperature of 3 zones is set to 140 ℃, and the hot press temperature of 4 zones is set to 130 ℃ according to the advancing direction of the slab band. The hot pressing speed was 105m/min. The pressure of the 1 area is 35bar to 50bar, the pressure of the 2 area is 25bar to 55bar, the pressure of the 3 area is 55bar to 80bar, and the pressure of the 4 area is 120bar to 150bar. Representation of
Post-treatment:
and conveying the hot-pressed plates to the plate overturning frame through a conveying belt according to the requirement, cooling, and then stacking and packaging.
The following examples are provided in accordance with the inventive concepts. The processes not mentioned separately in the examples use the preferred modes described in the sections above. The performance index of each example was tested according to the following test method.
Density measurement: the density measurement was carried out according to the method of 4.2 in GB/T17657-2013. And (3) water content measurement: the water content was measured according to the method for measuring water content specified in GB/T17657-2013 at 4.3. Static flexural Strength, elastic modulus measurement: the static bending strength and the elastic modulus were measured according to the method defined in GB/T17657-2013 at 4.7. Measurement of internal bond Strength: the inner bond strength was measured according to the method prescribed in GB/T17657-2013 at 4.11. Water absorption measurement: the measurement was carried out according to the 24-hour water absorption measurement method prescribed in GB/T17657-2013 at 4.6. Formaldehyde release amount: the measurement was carried out in accordance with the measurement specification of formaldehyde release amount in GB 18580-2017.
Example 1
Flaking the New Zealand radiation pine log material by a flaking machine, wherein the length and the width of the flaked log are 5 cm-8 cm, and the thickness is 1 cm-2 cm. The planed wood chips are subjected to water washing and dehydration, then are subjected to temporary storage through a preheating buffer bin before entering a thermal mill through a closed conveying belt, are formed into wood plugs after diameter-changing screw extrusion, are sent into a vertical digester for boiling and softening treatment, the boiling pressure is 7.5bar, the boiling temperature is 162 ℃, and the boiling treatment time is 3.5min. The steamed wood chips are sent into a thermal mill for thermal milling, and the melted 58# full refined paraffin is added into the thermal mill with the addition amount of 8kg/m 3 Obtaining 50-100 mesh pine fiber, and passing the qualified fiber into a drying pipeline. The urea-formaldehyde resin adhesive, ammonium chloride and paraffin are applied in a spray manner through respective metering pipelines, so that the urea-formaldehyde resin adhesive, the ammonium chloride and the paraffin form an impact type mixing state with the fiber flow of the pipelines, and the materials are uniformly distributed on the surface of the fibers, wherein the urea-formaldehyde resin adhesive has a solid content of 51%, an application amount of 12.5%, the ammonium chloride has a solid content of 20%, an addition ratio of 0.4%, the paraffin has a solid content of 100% and an addition amount of 0.8%. The fibers are subjected to hot grinding and sizing so that the fibers are dried through a drying system, the temperature of an inlet pipeline of the drying system is controlled to be 100 ℃, the temperature of an outlet pipeline of the drying system is controlled to be 60 ℃, the water content of the fibers is 7%, the fibers are paved into a continuous slab band through a paving forming machine, and the density of an ultrathin fiber board with the thickness of 0.8mm of a target board is set to be 1050Kg/m 3 The width of the slab band is 1250mm, and according to the density requirement, the paving machine performs blanking through a spiral blanking device, and the paving height deviation is +/-3 mm. And conveying the paved slab band to a preformer through a conveying belt, wherein the preforming pressure is 100bar. The pre-pressed slab band is conveyed to a hot press, 6.8mm is arranged at the entrance of the slab band, the hot press is divided into 4 continuous pressure intervals, and according to the advancing direction of the slab band, the hot press temperature of 1 area is 175 ℃, the hot press temperature of 2 area is 165 ℃, the hot press temperature of 3 area is 140 ℃, the hot press temperature of 4 area is 130 ℃, the hot press speed is 105m/min, the pressure of 1 area is 50bar, the pressure of 2 area is 55bar, the pressure of 3 area is 80bar, and the pressure of 4 area is 150bar. And conveying the hot-pressed plates to the plate overturning frame through a conveying belt, cooling, and then stacking and packaging.
Example 2
Will be new western styleThe blue radiation loose log material is sliced by a flaker, and the length and the wide size range of the sliced log material are 5 cm-8 cm and the thickness is 1 cm-2 cm. The planed wood chips are subjected to water washing and dehydration, then are subjected to temporary storage through a preheating buffer bin before entering a thermal mill through a closed conveying belt, are formed into wood plugs after diameter-changing screw extrusion, and are sent into a vertical digester for cooking and softening treatment, wherein the cooking pressure is 8.0bar, the cooking temperature is 160 ℃, and the cooking treatment time is 4.0min. The digested wood chips are sent into a thermal mill for thermal milling, and the melted 58# fully refined paraffin is added into the thermal mill with the addition amount of 10kg/m 3 Obtaining 50-100 mesh pine fiber, and passing the qualified fiber into a drying pipeline. The urea-formaldehyde resin adhesive, ammonium chloride and paraffin are applied in a spray manner through respective metering pipelines, so that the urea-formaldehyde resin adhesive, the ammonium chloride and the paraffin form an impact type mixing state with the fiber flow of the pipelines, and the materials are uniformly distributed on the surface of the fibers, wherein the urea-formaldehyde resin adhesive has a solid content of 51%, an application amount of 12.5%, the ammonium chloride has a solid content of 20%, an addition ratio of 0.45%, the paraffin has a solid content of 100% and an addition amount of 0.8%. And drying the fibers obtained by hot grinding through a drying system, controlling the temperature of an inlet pipeline of the drying system to be 110 ℃, controlling the temperature of an outlet pipeline to be 55 ℃, and controlling the water content of the fibers to be 6.7%. The fiber is paved into a continuous slab band by a paving forming machine, and the density of the 0.8mm ultrathin fiber board of the target board is set to be 1050Kg/m 3 The width of the slab band is 1250mm, and according to the density requirement, the paving machine performs blanking through a spiral blanking device, and the paving height deviation is +/-3 mm. And conveying the paved slab band to a preformer through a conveying belt, wherein the preforming pressure is 95bar. The pre-pressed slab band is conveyed to a hot press, 6.8mm is arranged at the entrance of the slab band, the hot press is divided into 4 continuous pressure intervals, and according to the advancing direction of the slab band, the hot press temperature of 1 area is 175 ℃, the hot press temperature of 2 area is 165 ℃, the hot press temperature of 3 area is 140 ℃, the hot press temperature of 4 area is 130 ℃, the hot press speed is 105m/min, the pressure of 1 area is 35bar, the pressure of 2 area is 40bar, the pressure of 3 area is 55bar, and the pressure of 4 area is 130bar. And conveying the hot-pressed plates to the plate overturning frame through a conveying belt, cooling, and then stacking and packaging.
Example 3
Flaking the New Zealand radiant pine log material with a flaker,the length and the width of the wood chips after flaking are 5 cm-8 cm, and the thickness is 1 cm-2 cm. The planed wood chips are subjected to water washing and dehydration, then are subjected to temporary storage through a preheating buffer bin before entering a thermal mill through a closed conveyor belt, are formed into wood plugs after diameter-changing screw extrusion, are sent into a vertical digester for steaming and softening treatment, the steaming pressure is 7.5bar, the thermal mill temperature is 165 ℃, and the steaming treatment time is 4.0min. The digested wood chips are sent into a thermal mill for thermal milling, and the melted 58# fully refined paraffin is added into the thermal mill with the addition amount of 9kg/m 3 Obtaining 50-100 mesh pine fiber, and passing the qualified fiber into a drying pipeline. The urea-formaldehyde resin adhesive, ammonium chloride and paraffin are applied in a spray manner through respective metering pipelines, so that the urea-formaldehyde resin adhesive, the ammonium chloride and the paraffin form an impact type mixing state with the fiber flow of the pipelines, and the materials are uniformly distributed on the surface of the fibers, wherein the urea-formaldehyde resin adhesive has a solid content of 51%, an application amount of 12.5%, the ammonium chloride has a solid content of 20%, an addition ratio of 0.5%, the paraffin has a solid content of 100% and an addition amount of 0.8%. Drying by a drying system, and controlling the temperature of an inlet pipeline of the drying system to be 110 ℃; the outlet pipe temperature was controlled at 68℃and the fiber moisture content was 6.5%. The fiber is paved into a continuous slab band by a paving forming machine, and the density of the 0.8mm ultrathin fiber board of the target board is set to be 1050Kg/m 3 The width of the slab band is 1250mm, and according to the density requirement, the paving machine performs blanking through a spiral blanking device, and the paving height deviation is +/-3 mm. And conveying the paved slab band to a preformer through a conveying belt, wherein the preforming pressure is 130bar. The pre-pressed slab band is conveyed to a hot press, 6.8mm is arranged at the entrance of the slab band, the hot press is divided into 4 continuous pressure intervals, and according to the advancing direction of the slab band, the hot press temperature of 1 area is 175 ℃, the hot press temperature of 2 area is 165 ℃, the hot press temperature of 3 area is 140 ℃, the hot press temperature of 4 area is 130 ℃, the hot press speed is 105m/min, the pressure of 1 area is 40bar, the pressure of 2 area is 25bar, the pressure of 3 area is 60bar, and the pressure of 4 area is 120bar. And conveying the hot-pressed plates to the plate overturning frame through a conveying belt, cooling, and then stacking and packaging.
The fiberboards prepared according to examples 1-3 were tested according to the test standards above and the results are shown in the table below.
TABLE 1
It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention. The invention may be variously modified within the scope defined by the claims. New variations and the like, obtained by combinations of different implementations or embodiments, and common technical means, are also considered to be included in the scope of the present invention.
Claims (10)
1. A preparation method of a low-aldehyde ultrathin fiber board,
the method is characterized by comprising the following steps:
and (3) cooking: steaming the qualified wood chips, wherein the steaming pressure is 7.5 bar-8.0 bar, the steaming temperature is 160-165 ℃, and the steaming time is 3.5-4.0 min;
and (3) heat grinding: adding melted 58# fully refined paraffin into the steamed wood chips and carrying out hot grinding to obtain 50-100 mesh wood fibers;
sizing: uniformly applying urea-formaldehyde resin adhesive and an auxiliary agent on the surface of the wood fiber in a drying pipeline;
and (3) drying: drying the glued wood fibers to obtain a pavement material with the water content of 6.0-6.5%;
paving: paving the paving material into a continuous slab band, setting the thickness of the target plate to be 0.8mm and the density of the fiber plate to be 1050Kg/m 3 ；
And (3) hot pressing: the slab band is sent to a hot press for hot pressing, the hot press is provided with four continuous pressure zones, the hot pressing temperature of the four pressure zones is gradually reduced according to the advancing direction of the slab band, and the hot pressing pressure of at least the three pressure zones is gradually increased,
wherein, the entrance of the slab is set to be 6.8mm, and the slab band advancing direction is set as follows: the hot-pressing temperature in the first section is 175 ℃, the hot-pressing temperature in the second section is 165 ℃, the hot-pressing temperature in the third section is 140 ℃, and the hot-pressing temperature in the fourth section is 130 ℃; the hot pressing pressure of the first interval is 35 bar-50 bar, the hot pressing pressure of the second interval is 25 bar-55 bar, the hot pressing pressure of the third interval is 55 bar-80 bar, and the hot pressing pressure of the fourth interval is 120 bar-150 bar; the hot pressing speed was 105m/min.
2. The process according to claim 1, wherein,
the qualified wood chips are wood chips with the length of 5 cm-8 cm, the width of 5 cm-8 cm and the thickness of 1 cm-2 cm and the water content of 55% -65%.
3. The process according to claim 2, wherein,
the preparation of the qualified wood chips comprises the following steps of water washing treatment: the flaking with the length of 5 cm-8 cm, the width of 5 cm-8 cm and the thickness of 1 cm-2 cm is washed and dehydrated, and the water content of the wood chips is controlled to be 55% -65%.
4. The process according to claim 3, wherein,
the preparation of the qualified wood chips further comprises preheating treatment: preheating the washed wood chips, and controlling the preheating temperature to be between 90 and 98 ℃.
5. The process according to claim 4, wherein,
the preparation of the qualified wood chips further comprises the step of shaping treatment: and extruding the preheated wood chips by a reducing screw to form a wood plug.
6. The process according to claim 1, wherein,
the addition amount of the 58# full refined paraffin is 8kg/m relative to the volume of the finished fiberboard 3 ～10kg/m 3 。
7. The process according to claim 1, wherein,
the solid content of the urea-formaldehyde resin adhesive is 49-53%, and the application amount of the urea-formaldehyde resin adhesive is 11-13% relative to the weight of the absolute dry fiber.
8. The process according to claim 1, wherein,
the auxiliary agent comprises a curing agent and paraffin wax,
the curing agent is ammonium chloride, and the addition amount of the curing agent is 0.40-0.50% relative to the weight of the absolute dry fiber;
the solid content of paraffin is 100%, and the addition amount of the paraffin is 0.7-0.9% relative to the weight of the absolute dry fiber.
9. The process according to claim 1, wherein,
the hot pressing treatment is preceded by a pre-pressing treatment: pre-pressing the paved slab band, wherein the pre-pressing pressure is 95 bar-130 bar.
10. A low-formaldehyde ultrathin fiberboard prepared by the preparation method of any one of claims 1 to 9.
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Inventor after: Wei Ming Inventor after: Min Dexiu Inventor after: Dong Rongdan Inventor after: Qi Zhichao Inventor before: Yu Santong Inventor before: Dong Rongdan Inventor before: Wei Ming Inventor before: Min Dexiu Inventor before: Qi Zhichao |