A kind of method of wood materials compression compactTechnical field
The invention belongs to wood materials to produce preparation field, more specifically to a kind of wood compression densification andThe method for improving composite wooden material bonding strength.
Background technique
53,250,000 hectares of the artificial Linda in China, ranks first in the world.Compared with wildwood, artificial forest has growth fast, rawThe features such as long amount is high, exploitation is convenient and obtains more stable benefit morning, timber and lumber standards, quality, utilization easy to process.But artificial forestMake since there are some material defects if fast-growing Chinese fir material is poor, short texture, intensity and hardness are low, not wear-resisting, easy to moisture absorptionIts industrial applications is very restricted.Therefore, the correlated performance for improving fast growing wood is to expand its utilization scope masterWant one of method.
Common timber enhanced processing method has resin infusion method and compression compact method.Impregnation timber is most widely squareMethod is vacuum impregnation method, i.e., timber first vacuumizes under certain condition of negative pressure, then utilizes process tank internal and external pressure difference by stainResin injects timber in tank, and is kept for the corresponding time.But timber is a kind of heterogeneous natural material of porosity, and respectively to differentProperty it is big, so resin is often uneven in the distribution of wood internal using after various low-molecular-weight resin impregnation timber,And the chemical reagent being added has certain influence to human health and earth environment.But in the prior art under vacuum state at dippingTimber is managed, and takes pressurization (hot pressing), does not have relevant document to record, if simply simultaneously by impregnation timber under vacuum stateHot-pressing processing is carried out, the effect of dipping and hot pressing is often not achieved, while chemical reagent can not be solved to human health and groundThe problems such as ball environmental pollution.
Compression compact is a kind of high-quality technology utilized of bad material.Fast growing wood compression compact is that one of its modification is importantDirection, the purpose is to improve its related physical, mechanical property.After fast growing wood is handled by compression compactization, it is hard that it can be improvedDegree, wearability and dimensional stability, so as to partially broadleaf be replaced to use.
Conventional wood compression densification technologies mainly include sofening treatment, transverse compression and the compressed deformation before compressionThree steps are fixed, technology production time length, low efficiency.Although the density of wood after the technical treatment increases, compare mouldAmount does not improve or even the specific modulus of timber can reduce instead, and therefore, the performance of timber is not promoted well.In addition,In wood compression compacting process, polysaccharide, hemicellulose and extract in Wood chemical composition have occurred degradation, oxidation,A series of chemical changes such as polycondensation, coloring matter content increases, so that wood surface color burn, affects the beauty of productSight and quality.
Chinese invention patent, publication number: publication date: CN102198679B on March 26th, 2014, discloses a kind of fast-growingThe method of flooring board enhancing processing.This method is handled according to following order: a. is close by fast-growing floor base material using hot pressRealification；B. the fast-growing plate of densification is realized into surface carbonation on heating platen；C. radio frequency plasma method of modifying is used, is allowedNitrogen plasma carries out gas-solid two-phase chemistry lamination with carbon and is nitrogenized.Through the inventive method treated fast-growing flooring boardHave the advantages that surface hardness is high, wear-resisting, the disadvantages are as follows: the invention from it is closely knit to carbonization again to nitridation, complex process, processingPeriod is long, takes 80~120 DEG C in hot pressing temperature, and hot pressing pressure takes 0.8~2.0MPa, and the time takes and carries out under conditions of 5~15minHeat pressing compact, plate will appear rebound, and dimensional stability is bad；In addition, in 200 DEG C or more of high temperature after the processing of substrate densificationCarbonization treatment is carried out to it under environment, the texture color for easily causing wood surface to change colour, thus destroying China fir itself.
Chinese invention patent, publication number: publication date: 101875207 A of CN discloses low-quality speed on November 3rd, 2010Growing log in situ is closely knit and the processing method of bacteriostat degerming functions, comprising: by pressurization and vacuumizes in vacuum pressed tankFiller will be planted low-quality fast growing wood progress closely knit and antibacterial bacteriostatic in situ and handled by technique.The invention low operation temperature, to timberWithout compression, belong in situ closely knit.But disadvantage is that: (1) invention needs to add additional filler, thus increasesExtra-pay, higher cost；(2) time of filler infiltration wood internal is longer, thus the entire sheet fabrication periodIt is longer；
(3) timber density after impregnating substantially increases, though Deflection Modulus of Elasticity improves 36.2%, the specific modulus of materialBut it substantially reduces, affects the performance of material.
Chinese invention patent, publication number: CN103433982B, publication date: on August 5th, 2015 discloses cross-bedding pressing plateMaterial processing method, specifically include laminate prepare, composite modifier configuration, the modified enhancing of surface layer laminate, laminate refer to connect, laminate is appliedGlue, assembly, compacting, post-production.The modified enhancing technique of surface layer laminate include surface layer laminate is put into it is right in closed pressurized tankPressurized tank, which is repeated, to be vacuumized and pressurized treatments, composite modifier are impregnated under pressure in the laminate of surface layer, for rowThe extra composite modifier in ejecting plate surface layer, then to seal-off pressure tank vacuumize process.By modified enhancing in assembly, pressing processLaminate is placed in surface layer and carries out assembly according to the mutually perpendicular mode of grain direction of adjacent laminate, and cold pressing is put into a press after assemblyMolding, while being subject to lateral pressure.The disadvantages are as follows: the time that (1) composite modifier penetrates into wood internal is longer thus wholeA sheet fabrication period is also longer；(2) plate is placed in pressurized tank and vacuumizes progress impregnation and is modified by the invention, then willTreated that plate carries out press compression enhancing processing in a normal state for impregnating by pressure, and for fast-growing Chinese fir etc., itself pit is closeReal timber, modifying agent is difficult to penetrate into, and material surface property is also changed after impregnation.There are still conventional dippingsThe various defects of processing.
In addition, the formation of bonding strength is a complicated process when wood gluing, it is broadly divided into following 5 steps: streamDynamic, transmitting, infiltration, wetting and solidification.The production of glued board at present is frequently with urea-formaldehyde resin adhesive, in glued board or other woodIn composite material manufacturing process, since timber is porous material, adhesive can be aggravated in hot pressing and penetrated at veneer, glueIt closes the gluing agent content at layer to reduce, seriously affects glued effect, thereby reduce the final bonding strength of glued board.This is alsoThe above-mentioned prior art or the industry technical problem also to be solved.
Summary of the invention
1, it to solve the problems, such as
For defect present in existing impregnation and wood compression densification technology and conventional Wood compositeThe problems such as production cycle is long in material manufacture processing, high production cost, production equipment utilization efficiency is low and product mechanical property is poor,The invention discloses a kind of methods of wood materials compression compact, can play compression, fixation and setting to wood materials simultaneouslyPurpose, and the mechanical strengths of wood materials fully meets requirements after handling, the standby compressed wood material with the common hot pressing of useMaterial is compared, and color difference is small, and bending strength is high, and specific modulus is big, while also improving the bonding strength of existing wooden glueing material.
2, technical solution
To solve the above problems, the present invention adopts the following technical scheme that:
A kind of wood materials compression compact method, comprising the following steps:
It pressurizes to wood materials in vacuum state；Moulding pressure takes 1-4MPa；After reaching pressing time, vacuum is gone,Carry out release, cooling.
Preferably, wood materials are carried out in vacuum state hot pressing；The hot pressing temperature takes 100 DEG C -220 DEG C, hot pressingPressure takes 1-4MPa；After reaching hot pressing time, vacuum is gone, carries out release, cooling.
It is described in vacuum state hot pressing, vacuum degree is -0.1MPa~-0.09MPa.
Wood materials compression compact method and step further include wood materials are dried and sanding surface processing；To dryTreated that wood materials are cut for the processing of dry and sanding surface.
The wood materials are timber or composite wooden material, and the composite wooden material is glued board, structure collectionIt becomes a useful person, particieboard or structural veneer laminated timber.
The drying and sanding surface processing treated lumber thickness are 18-22mm；Whole moisture content is 10 ± 2%.
The wood materials are that timber first vacuumizes before compression, and vacuum degree is -0.1MPa~-0.09MPa, the heatPressure temperature takes 160 DEG C -220 DEG C, and hot pressing time takes 15min-45min, and hot pressing pressure takes 2-4MPa；Allow entire wood compression closeRealification process is always all in vacuum state.
The manufacturing method of wood materials compression compactization raising wood materials bonding strength, comprising the following steps:
(1) by timber rotary-cut or slicing at Wooden veneer；
(2) to treated in step (1), Wooden veneer is dried；
(3) to treated in step (2), Wooden veneer carries out covering with paint adhesive；
(4) to treated in step (3), Wooden veneer carries out assembly；
(5) to treated in step (4), slab carries out vacuum hotpressing, and vacuum degree is -0.1MPa~-0.09MPa, hot pressingTemperature takes 100 DEG C -120 DEG C, and hot pressing time takes 50-90s/mm, and hot pressing pressure takes 1-2MPa；
(6) to treated in step (5) slab, after reaching hot pressing time, vacuum, release, cooling, cutting edge and sanding are goneProcessing, is finally made the glued board of high bonding strength.
Wooden veneer whole moisture content after being dried is 8 ± 3% in the step (2).
The adhesive is urea-formaldehyde resin adhesive at the step (3), and two-sided resin added is 200-300g/m2,Slab described in step (4) is vertical, and-cross-indulges three layers or odd-level assemble pattern.
3, beneficial effect
Compared with the prior art, the invention has the benefit that
(1) method of wood materials compression compact provided by the invention increases the surface layer density of material by compression,Mechanical strength is improved, while improving the stability of material.Vacuumize process makes entire hot pressing in the condition of anaerobicLower progress, reduces the degradation of content of material, guarantees that significant change will not occur for the wood color of timber, while accelerating timber againThe migration of internal moisture, it is certain as losing for hydrone causes the hydrogen bond of molecule between wood chemical compositions and reconfigureChemical group changes, and forms crosslinked action, under the effect of external force, so that the directionality between microfibril is improved,Crystallinity improves, and improves compression effectiveness.Softening and Partial digestion occur timber for lignin and hemicellulose under the high temperature conditions, micro-Fibril easily moves, and constitutes the molecular moiety of stroma ground substance by partial cutoff, and internal stress is relaxed rapidly, when temperature reducesWhen, stroma ground substance returns to glassy state from viscous state again, it is suppressed that the flexible deformation of microfibril, compressive deformation are fixed.Thus the present invention realizes hot pressing, fixation and setting function simultaneously, and solving ordinary hot, to depress timber easy to change and stability is poorProblem；
(2) the secondly method of wood materials compression compact of the present invention, the boiling point of liquid is lower under vacuum condition, unit bodiesMolecular number is greatly reduced in product, and the molecular collision probability being evaporated reduces, that is, is not easy to return after being evaporated.In vacuum conditionUnder to timber carry out high temperature hot pressing processing when, vacuum environment pressure is lower, by means of differential pressure action, easily by timber moisture steamOut, under the combination of stringent pressure and temperature, timber densification is promoted；
(3) method of wood materials densification provided by the invention, compared with prior art, without any additive to woodMaterial carries out impregnation etc., thus entire working process process is environmentally protective, thus, wood materials obtained are free of nuisanceMatter, and the timber densification time of the present invention is very short, facilitates the raising of production efficiency；
(4) method of wood materials densification provided by the invention, wood materials are after vacuum hotpressing is handled, solid wood boardHemicellulose inside material is degraded, and mass loss rate increases, and internal porosity reduces, the wood for being included in unit volumeThe quality of material cell wall substance increases, and density of wood increases therewith, and the effective active area for bearing external force becomes larger, through the short time andUnder hot pressing condition, the Deflection Modulus of Elasticity of material is greatly improved after rapid hot pressing, and the increase degree of elasticity modulus is greater than densityIncrease degree, the specific modulus of material substantially increases；
(5) method of wood materials densification provided by the invention, while wood materials bonding strength is also improved, using trueEmpty hot-pressing technique, with regard to carrying out vacuumize process before hot pressing, the boiling point of substance is reduced, and wood internal moisture can be in lower temperatureUnder reach boiling point vaporization, wood surface water evaporation rate accelerate, accelerate speed of the wood internal moisture to external migration, thusSo that glue-line is easier to solidify, improves the bonding strength of wood materials and shorten gluing time.
(6) method provided by the invention for improving wood materials bonding strength, using vacuum hot pressing technique, material is in anaerobicUnder conditions of carry out glued, reduce the palliating degradation degree of timber content, wood color made not change；Various solid matters are bigIn air pressure environment, surface can adsorb some gases, when being in vacuum, since density of gas molecules reduces, and the gas being adsorbedIt can release into environment, the burst size of methanal of composite wooden material can be also reduced using vacuum technique；It is also prevented from simultaneouslyAdhesive generates unfavorable chemical reaction at high temperature, is further ensured that bonding quality.
Specific embodiment
The present invention is further described below combined with specific embodiments below.
Embodiment 1
The specific test procedure of this experiment is as follows:
1) be dried to fir wood plank and sanding surface is handled: by with a thickness of the fir wood plank of 23-24mm, sanding is extremely22mm, moisture content is 10% after drying.
2) to the processing of dry and sanding surface, treated that fir wood plank is cut: using sizing saw machine be made 200mm ×The China fir test specimen of 100mm × 20mm (axial × tangential × radial).The rulers such as precise measurement test specimen quality, width, thickness and lengthVery little (position when measurement thickness is marked) record and numbered to the data of measurement test specimen accurately to 0.02mmIt arranges.
3) numbered test specimen compression processing is carried out to test specimen under vacuum and condition of normal pressure respectively using hot press (to hang downStumpage tangential compression): the pressure of high temperature hot pressing contracting processing is 2MPa, compression ratio 30%, hot pressing time 30min, hot pressingTemperature is 180 DEG C, 200 DEG C and 220 DEG C three kinds.After hot pressing time to be achieved, vacuum, removal pressure are gone, it is cooling, most final pressure is madeContracting wood.Wherein, it goes first close vacuum valve when vacuum hotpressing, opens vacuum (-tight) housing, then carry out release again.
4) thickness of test specimen after compression processing (measuring in mark) and weight are measured and is recorded.
5) it measures and calculates compressed using CIE (1976) L*a*b colour system that International Commission on Illumination is recommendedThe value of chromatism of test specimen and untreated test specimen.
6) Deflection Modulus of Elasticity detection is carried out to compressed test specimen using omnipotent mechanics machine.
Wood materials Deflection Modulus of Elasticity detection data (the GB/T 1936.2- obtained according to the process of embodiment 12009), as shown in table 1.
The detection data of 1 material Deflection Modulus of Elasticity of table
The detection data of 2 test specimen value of chromatism of table
The specific modulus data of 3 vacuum hotpressing test specimen of table
Result of implementation explanation carries out compression processing to timber under vacuum conditions, can effectively improve the bending resistance springform of materialAmount and specific modulus, and compared with conventional compression material, material surface color color difference is small.
Embodiment 2
With embodiment 1, difference is this test implementation steps,
1) sawing: will be with a thickness of the fir wood plank of 21-23mm, sanding to 20mm, moisture content 10%.
2) vacuum hotpressing: hot pressing pressure 2MPa, compression ratio 30%, hot pressing time 15min, hot pressing temperature 180DEG C, 200 DEG C and 220 DEG C three kinds.
4) release.
The wood materials detection data obtained according to the process of embodiment 2 is as follows.
4 experimental test data of table
Vacuum compression time in embodiment 2 is compared with shortening 15min, compared with Example 1, compressed wood in embodiment 1Intensity improving rate is lower, and value of chromatism is smaller, i.e., surface color is more difficult changes.
Embodiment 3
If step is with embodiment 2, difference is sanding to 18mm, and moisture content 12%, compression ratio when vacuum hotpressing is20%, compression time 30min.
Shown in the detection data table 5 of the wood materials obtained according to the process of embodiment 3:
5 experimental test data of table
Embodiment 4
For step with embodiment 2, difference is when vacuum hotpressing is closely knit that vacuum compression rate is 10%, compression time 30min,Hot pressing temperature is 200 DEG C.Obtained compressed wood is detected according to relevant regulations and standard.Result of implementation shows vacuum compressionTreated test specimen Deflection Modulus of Elasticity and specific modulus have been respectively increased 42.77%, 20.91% compared with material, and value of chromatism is5.92%.
Embodiment 5
With embodiment 2, difference is step, and test specimen is 8% by drying control moisture content before compression processing, hot pressingTemperature is 180 DEG C, and obtained compressed wood is detected according to relevant regulations and standard.Vacuum hotpressing treated test specimen bending resistanceElasticity modulus and specific modulus have been respectively increased 33.36%, 10.26% compared with material, value of chromatism 6.11%.
Embodiment 6
With embodiment 2, difference is step, and test specimen is 10% by drying control moisture content before compression processing, hot pressingTemperature is 160 DEG C, and compression time is that the compressed wood that 45min is obtained is detected according to relevant regulations and standard.Vacuum hotpressingTreated test specimen Deflection Modulus of Elasticity and specific modulus have been respectively increased 20.64%, 7.55% compared with material, and value of chromatism is5.78%.
Embodiment 7
With embodiment 2, difference is step, and test specimen is 10% by drying control moisture content, adds before compression processingPressure, compression time are that the compressed wood that 45min is obtained is detected according to relevant regulations and standard.Vacuum hotpressing treated examinationPart Deflection Modulus of Elasticity and specific modulus have also respectively obtained raising compared with material.
Embodiment 8
A kind of wood materials compression compact method, includes the following steps:
1) slicing and drying: the good China fir veneer of slicing (no crack degree), with a thickness of the Wooden veneer of 1.6-1.8mm,It is carried out in drying box, drying temperature is 50 DEG C, time 12h, and whole moisture content is 8%.
2) gluing: the Wooden veneer after drying is subjected to covering with paint adhesive, two-sided resin added is 300g/m2。
3) assembly :-horizontal-according to the vertical of glued board to indulge three layers of assemble pattern, prepare the slab of three layers of glued board.
4) vacuum hotpressing: after slab is put into press, closing vacuum (-tight) housing, vacuumize, and hot pressing temperature is 110 DEG C, slab pressurePower is 1.0MPa, hot pressing time 60s/mm.
5) release: after reaching hot pressing time, going vacuum, and hot pressing terminates, and slab is taken out in release, then cooling, cutting edge and sandGlued board is made in light processing.
According to the glued board detection data (GB/T 17657-2013) for the wood materials that the process of embodiment 8 obtains, such as tableShown in 6:
The bonding strength detection data of 6 wood materials glued board of table
This result of implementation shows to carry out hot pressing under vacuum conditions, is remarkably improved the bonding strength of glued board.Using trueEmpty hot-pressing processing, hence it is evident that improve wood materials bonding strength.
Embodiment 9
With embodiment 6, difference is step, and veneer is 11% by drying control moisture content, when gluing two-sided resin addedFor 280g/m2, vacuum hotpressing temperature is 120 DEG C, and slab pressure is 1.5MPa, vacuum hotpressing time 50s/mm, obtained gluingPlate is detected according to relevant regulations and standard, and bonding strength reaches 1.956MPa, is improved compared to the China for plywood under normal pressure42.13%.
Embodiment 10
With embodiment 6, difference is step, and veneer is 5% by drying control moisture content, and when gluing, two-sided resin added was250g/m2, vacuum hotpressing temperature is 100 DEG C, vacuum hotpressing time 90s/mm, and obtained glued board reaches through detecting bonding strength2.115MPa improves 24.6% compared to the China for plywood under normal pressure.
Embodiment 11
With embodiment 6, difference is step, and China fir veneer thickness is 2mm, is 9% by drying control moisture content, gluingWhen two-sided resin added be 240g/m2, vacuum hotpressing temperature is 90 DEG C, and vacuum hotpressing time 60s/mm, obtained glued board is through examiningIt surveys bonding strength and reaches 1.879MPa, improve 37.36% compared to the China for plywood under normal pressure.
Embodiment 12
A kind of wood materials compression compact method, includes the following steps:
1) slicing and drying: the good board using poplar board of slicing (no crack degree), with a thickness of the Wooden veneer of 1.6-1.8mm,It is carried out in drying box, drying temperature is 50 DEG C, time 12h, and whole moisture content is 10%.
2) gluing: the Wooden veneer after drying is subjected to covering with paint adhesive, adhesive is phenolic resin, and solid content is65%, two-sided resin added is 300g/m2。
3) according to the assemble pattern of laminated veneer lumber, 15 layers of structural veneer laminated timber assembly: are prepared.
4) vacuum hotpressing: after slab is put into press, closing vacuum (-tight) housing, vacuumize, and hot pressing temperature is 145 DEG C, slab pressurePower is 1.0MPa, hot pressing time 60s/mm.
5) release: after reaching hot pressing time, going vacuum, and hot pressing terminates, and slab is taken out in release, then cooling, cutting edge and sandStructural veneer laminated timber is made in light processing.
The structural veneer laminated timber detection data (GB/T 20241-2006) obtained according to the process of embodiment 12, such as table 7It is shown:
The bonding strength detection data of 7 veneer level material of table
Embodiment 13:
The manufacturing method for improving wood materials laminated wood bonding strength, includes the following steps:
1) the pinus sylvestris var. mongolica sawn timber (width 140mm, thickness 10mm) made, moisture content 12% saw lumber: are sawed.
2) gluing: covering with paint adhesive is carried out to the pinus sylvestris var. mongolica after drying, adhesive is resorcinol-phenol-formaldehyde copolymerizationResin, solid content 50%, two-sided resin added are 260g/m2。
3) assembly: according to the assemble pattern of integrated timber, three-decker integrated timber is prepared.
4) vacuum hotpressing: after slab is put into press, closing vacuum (-tight) housing, vacuumize, and hot pressing temperature is 145 DEG C, slab listPosition pressure is 1.0MPa, hot pressing time 60s/mm.
5) release: after reaching hot pressing time, going vacuum, and hot pressing terminates, and slab is taken out in release, then cooling, cutting edge and sandStructural glulam is made in light processing.
GB/T 26899-2011 is detected the integrated timber obtained according to the process of embodiment 13 according to national standards, is led toIt crosses the glue-line shear strength (6.74MPa) that is averaged of integrated timber made of vacuum hotpressing to meet the requirements of the standard (6.0MPa), and is higher than normalDepress produced integrated timber bonding strength.
Embodiment 14
Composite wooden material is particieboard, and for preparation step with conventional particieboard preparation method, adhesive is phenolic resin glue,Difference is vacuum hotpressing: after slab is put into press, closing vacuum (-tight) housing, vacuumizes, hot pressing temperature is 145 DEG C, slab unitPressure is 1.0MPa, hot pressing time 60s/mm.It is detected according to the particieboard that the process of embodiment 14 obtains, passes through vacuumThe glue-line shear strength that is averaged of particieboard made of hot pressing is met the requirements of the standard, and it is glued strong to be higher than the particieboard produced under normal pressureDegree.