CN106182326A - A kind of light burnt powder makees the environment-friendly type medium-density plate of inserts - Google Patents

Abstract

The present invention discloses a kind of light burnt powder and makees the environment-friendly type medium-density plate of inserts, and its composition is the wood fiber 70 80 by ratio of weight and the number of copies, light burnt powder 10 12, Lauxite 79, paraffin 0.8 1.2, sheet alkali 0.2 0.3, formic acid 0.2 0.3, ammonia chloride 0.25 0.3, tripolycyanamide 0.15 0.2；Auxiliary agent 0.05 0.08；Described light burnt powder refers to that magnisite stone is through 750 1100 DEG C of temperature lower calcination resulting materials.The invention have the advantage that saving timber usage amount, significantly reduce the burst size of methanal of high density fiberboard simultaneously, improve its environmental-protecting performance, improve the level of production and product quality, simultaneously facilitate the technological innovation of wood-based panel product, process innovation and products innovation.

Description

A kind of light burnt powder makees the environment-friendly type medium-density plate of inserts

Technical field

The present invention relates to building material field, the preparation method of a kind of medium-density plate.

Background technology

The forest reserves are rare environmental protection resources, are the recyclability money living of close concern to each other with people Source, the periodicity of its regeneration determines that its value is difficult to substitute.China is that one populous, the forest reserves are seriously burst weary Developing country, afforestation rate is 18.21%, per capita 1/10th of forest reserves owning rate deficiency world average level. Along with national economy high speed development and the rapid raising of people's quality of the life, timber demand has become the money of China's shortage the most One of source.

Medium/high density fiber board is as a kind of function admirable, of many uses, the artificial board plate that comprehensive utilization ratio is high Kind, has good market expectations and development prospect.

Medium/high density fiber board (MDF/HDF) is with wood fibre as raw material, through mechanical separation, apply pollopas or Other synthetic resin, then through mating formation, molding and the technique such as high temperature, conduction of heat compacting sheet material.The density of medium-density plate, power Performance, close to timber, is the most popular a kind of artificial board.Product can be widely used for medium/high shelves furniture, The industries such as sound equipment musical instrument, vehicle, boats and ships, building.Within 1998, the most leap to second place of the world.Although it is raw that China has become wood-based plate Produce one of big country, MDF produces the first big country, but a whether power.From production line single machine production scale, device fabrication Level, production Technology, product quality and specification kind, product quality and specification kind, the deep processing of product and market , all there is the biggest gap with advanced person developed regions, the world and country in application etc., this is a undisputable fact.

China's wood-based panel industry increases very fast, but year occupancy volume is only 0.014 inner side's rice, only quite world's average water per capita The 58% of flat 0.024 cubic metre.Within 2005, China is 2806 ten thousand steres to the consumption demand amount of wood-based plate, and by 2010 just It is 4180 ten thousand steres.Although China's wood-based panel industry develops comparatively fast at present, but it is in development, metamorphosis stage, with China Overall Industry Development Level is compared the most incompatible.

Outstanding behaviours is at three aspects:

One is unreasonable structure, with low content of technology.Plywood ratio is bigger than normal, and production and consumption accounts for 45% He the most respectively 50%, and world's plywood ratio is only about 35%.In recent years developed country is negative growth, and its main cause is to be limited by raw material System and other product sections replace caused, and OBS high-performance composite plate, inorganic adhesive wood-based plate, specific use sheet material ratio are inclined The feature boards such as thickness little, special and thin plate ratio are on the low side, and non-standard breadth plate is blank, moistureproof, fire-retardant produce less, deep processing and height New Products ratio the least (less than 20%).

Two is that management level are poor, and conforming product rate is low.Most little plywood industries belong to type backward in technique, for international 20th century The seventies level, within 1998, conforming product rate is only 69.6%；Most particieboards and medium density fiber enterprise produce and management water The Ping Wei world level eighties, most enterprises lack technology development capability, and technician is deficient.

Three is that product applications is narrow, and application technology falls behind.China's furniture wood-based plate accounts for 79%, wood-based plate for building Only account for about 15%；Annual less than 60 ten thousand steres (about 3%) as materials for wall；And it is American-European artificial as construction wall finishing Plate accounts for about 50%.Problem like this also has a lot, but this most impassable and overcome, a maximum difficult problem is raw material Critical shortage, Take me as I am state wood-based plate industry is hovered in crossroad, faces the reason of difficult choice.Wood-based Panel Production enterprise is such as What ensures that its raw materials for production abundance should will be the realistic problem faced by each non-forest zone enterprise, then, solve Wood-based Panel Production enterprise The outlet of industry raw material supply where？The comprehensive actual performance in various places and trend the most in recent years, various places most enterprise directly or Indirectly recognizing two practical ways, one is that enterprise notes cultivating and exploitation reserved resources, establishes base for producing sustainable development This；Two is to greatly develop non-wooden raw material to utilize.

Owing to forest tree resource reduced in recent years, its price also rises steadily, and causes enterprise profit constantly to decline, therefore, The inexpensive mineral that a kind of part could be found to substitute forest tree resource are all medium-density plates to produce artificial medium-density plate The dream of enterprise.

Summary of the invention

For solving above-mentioned technical problem, it is an object of the invention to substitute the wood fiber with part light burnt powder, it is achieved with ore deposit generation wood, Reduce cost, improve quality.The key technical problem solved is: one is that the light burnt powder selecting what standard then can meet production technology Requirement；Two be light burnt powder add how many pairs of product mechanical properties meet require and unaffected；Three is that light burnt powder is at He Daogong Sequence adds in which way can meet product technology requirement just；Four is the impact that light burnt powder adds on product content of formaldehyde.

Concrete technical scheme is as follows:

A kind of light burnt powder makees the environment-friendly type medium-density plate of inserts, and its composition is wood fiber 70-80 by ratio of weight and the number of copies, gently Burn powder 10-12, Lauxite 7-9, paraffin 0.8-1.2, sheet alkali 0.2-0.3, formic acid 0.2-0.3, ammonia chloride 0.25-0.3, trimerization Cyanamide 0.15-0.2；Auxiliary agent 0.05-0.08；Described light burnt powder refers to that magnisite stone is through 750-1100 DEG C of temperature lower calcination Resulting materials；Described auxiliary agent refers to tertiary amines catalyst aid.

Preparation method comprises the following steps:

(1) chip: pine weedtree material is whittled into the wood chip meeting production specification, separates for fiber and more preferable condition is provided；

(2) defibrator process: the preheated steaming and decocting of wood chip step (1) cut out, mechanical separation draws fiber；Including preheating steaming and decocting, Fiber separates, applying glue；

(3) it is dried: defibrator process grinds fiber and makes fiber moisture reach 40%-50% plus applying glue, if at not drying Reason fiber is difficult in adapt to follow-up workshop section, controls baking temperature at 165-168 DEG C；Also include step of dusting: in fiber drying process In, send mode by uniform for light burnt powder spray attachment in fiber surface with blower fan wind；

(4) mating formation: fiber delivers to spreading machine through feeding fan, pipe makes fiber stream even decline in a zigzag, and ensures that fiber falls Material uniformly, go out the slab of shaping box through sweeping through the material roller and by electronic weight-measuring device to adjust the amount of sweeping through the material so that slab is through mating formation Fiber obtain the density that sets；

(5) hot pressing: the slab of basic forming imposes the air within certain pressure and saw sanction eliminating through preformer so that Slab compression in bulk；

(6) saw limit: the purpose on saw limit is to ensure the specification that product is homogeneous；

(7) sanding: plate face is carried out sanding process

(8) plate embryo sorting；

(9) packing outbound.

In step (1): soft weedtree and hardwood ratio are 4:6；Chip dimensions is: long 16-30mm, wide 15-25mm, thick 3-5mm.

In step (2): described preheating boiling temperature 135 DEG C-175 DEG C, digestion time is 3-6 minute；Described fiber separates Use heated mechanical method；Described applying glue refers to: at defibrator fiber outlet, adds liquid urea aldehyde tree in steam glue spraying mode Fat, is attached to fiber surface；In Lauxite, carbamide is 1:1.15 with the mol ratio of formaldehyde.

In applying glue step: the method for the pH value of reaction medium, reaction temperature and response time terminal point control is:

1), formaldehyde put into, add sheet alkali, the pH value adjusting mixture is 8.5-8.8, puts into auxiliary agent and carbamide U1 (0.5375%), adding tripolycyanamide, open gas lift temperature, 70-75 DEG C closes gas, naturally rises temperature to 85-90 DEG C, be incubated 30 minutes, this The pH value of stage mixture is 6.5-6.6；(described auxiliary agent refers to tertiary amines catalyst aid, mainly has triethylene diamine, three second Amine, trimethyl benzylamine)；

2), controlling temperature 87-88 DEG C, add formic acid, the pH value adjusting mixture is 4.9-5.1, reacts 8-10 minute；

The pH value slowly adjusting mixture is 4.6-4.8, reacts 80-100 minute at 90-94 DEG C, and viscosity reaches 18.5- 19.5S/B4 33℃。

Adding sheet alkali, the pH value adjusting mixture is 6.8-7.0, puts into carbamide U2 (0.2375%), adds tripolycyanamide, at 82- 88 DEG C are reacted 30-35 minute, and the pH value of this stage mixture is 6.5-6.8, viscosity 18-19.5S/B4 30 DEG C；

3), adding sheet alkali, the pH value adjusting mixture is 7.2-7.5, cools to 75 DEG C, puts into carbamide U3 (0.225%), 65-70 DEG C is reacted 30 minutes, and the pH value of this stage mixture is 7.0；

4), lowering the temperature, add water simultaneously, add sheet alkali at about 45 DEG C, the pH value adjusting mixture is 8.0, and solid ammonium chloride adds water After being diluted to solubility 20%, with pump by it in glue, improve the hardening time of glue.

5) 40 DEG C to transfer glue, by heating paraffin to the liquid of 70-80 DEG C, is added by liquid paraffin at blow-off pipe by pump Enter fiber.

In step (3): drying mode uses the formal pneumatic conveying drying of one-level, heat is guided fiber by aerator Dry so that fiber obtains heat in the duct and vaporized by moisture, is dried inlet temperature 175-180 DEG C, outlet temperature 60-65 DEG C, dry medium uses by oily gentle heating groups of fins thus heat needed for reality heat drying system at short notice Air；

Dust: this operation is during fiber drying, send mode by uniform for light burnt powder spray attachment in fiber table with blower fan wind Face；It will store a period of time fiber at fiber feed bin after drying, delivers to spreading machine through the feeding blower fan batch mixing that dusts, utilizes vacuum Air-flow realizes the thick molding of fiber, then realizes, by sweeping through the material roller and preformer, the forming process that plate is bad.

The invention have the advantage that saving timber usage amount, significantly reduce the burst size of methanal of high density fiberboard simultaneously, Improve its environmental-protecting performance, improve the level of production and product quality, simultaneously facilitate the technological innovation of wood-based panel product, technique Innovation and products innovation.

Accompanying drawing explanation

Fig. 1 is the process chart of the present invention.

Detailed description of the invention

The technological process of the present invention is as it is shown in figure 1, illustrate the present invention below according to accompanying drawing；

The definition of light burnt powder:

" light burnt powder " is the abbreviation of " light-burning magnesium powder ", and its main component is magnesium oxide MgO.In the application, light burnt powder is Refer to magnisite stone as primary raw material, through 750-1100 DEG C of temperature lower calcination products therefrom.

Light-burning magnesium powder has a lot of capillary aperture, and PARA FORMALDEHYDE PRILLS(91,95) has stronger adsorption.Owing to it is that a kind of fire protection flame retarding is resistance to High-temperature material, therefore just can play anti-flaming function at a certain amount of light burnt powder of wood fiber surfaces stick, due to the cost of light burnt powder Lower than timber, utilize its filling can reduce consumption of wood, thus reduce the purpose of cost.

1, the main component (score ratio by weight) of the present invention is as shown in table 1

Table 1

2, technical method

This project select certain particle size, certain activity light burnt powder in wood fiber applying glue, wax spray, after drying powder is sprayed into, The most hot-forming, become the Midst density wood-based plate meeting country's E1 standard.

3, process route

Environment-friendlymedium-density medium-density fiberboard manufacturing process is as it is shown in figure 1, wherein:

↑ applying glue: this operation is at defibrator fiber outlet, adds liquid glue in steam glue spraying mode, is attached to fibre Dimension table face.

↑ light burnt powder: this operation is during fiber drying, send mode by uniform for light burnt powder spray attachment in fiber with blower fan wind Surface.

In following steps, the addition of various compositions is added in the ratio disclosed in table 1.

1. chip: it is the manufacturing shop of raw material during whole plate produces, and is mainly whittled into by pine weedtree material and meets production specification Wood chip, in case heat be fiber separate provide more preferable condition.

1.1 raw material types: MDF produces raw materials used Plant fiber, its content of cellulose typically more than 30%, What our company was benefited from is wood fibre, and it mainly includes logging residue (such as: small dimension wood, plate fork material, baked wheaten cake material), and producing material remains Excess (butt), adds residue (flaw-piece, reel, broken veneer and other leftover bits and pieces), and the waste and old wood etc. reclaimed, it is possible to The wood chip that direct forest zone or wood processing enterprise produce.

1.2 chip dimensions: wood chip size is qualified, uniform, smooth, chip dimensions is generally: long 16-30mm, wide 15- 25mm, thick 3-5mm, wood chipping equipment type of the present invention is drum chipper, produces to make wood chip be suitable for, in order to anti- Only feed auger is blocked up, and power consumption is high, on the one hand to adjust the gap of fly cutter and bed plate in good time, and the general gap adjusted is 0.8- 1.0mm.On the other hand to strengthen the reed time controll to raw aqueous rate rate, guarantee is not less than 40% as far as possible, so that wood chip is whole Neat uniform, qualification rate is high, broken quiet few, also improves cutter life.

1.3 pines weedtree proportioning (soft weedtree and hardwood ratio are 4:6)

Because the process conditions when intensity of MDF depends on the felt properties of fiber and combines, about fibre morphology, It is generally divided into fibrocyte (being commonly called as fiber) and heteroproteose cell, wherein the content of heteroproteose cell many with determine the good of fiber quality less With difference, it is however generally that, softwood heteroproteose cell content is minimum, and broadleaf takes second place, in addition to content affects quality, fiber shape The machining property etc. of state, chemical composition and raw material, the intensity of sheet material to be considered it is noted that following some: one Being that length is big, the fiber that length-width ratio is big has preferable binding ability；Two is that cell wall is relatively thin, and the smaller fiber in wall chamber is at fibre Dimension separates and easily flattens in hot pressing, becomes banding, better softness, has bigger contact area；Three is length, thickness The qualified collocation of fiber can increase contact surface with the space between fill fiber, improves product density and bond strength, about change The machining property of composition and raw material is not the most added and is stated, following indicator material material and broadleaf.

In sum, softwood and broadleaf is reasonably combined, it is possible to increase and stablize the mechanical property of material material.Except with On some beyond, strengthen the management of content of bark and ironware etc. aspect in the feed, because content of bark many impacts plate MOR, water absorption rate, and ironware can injury device, reduce running rate.

2. defibrator process, the preheated steaming and decocting of wood chip cut out in workshop of chipping, mechanical separation draws fiber.

2.1 preheating steaming and decoctings: the plasticity of raising fibrous raw material, reduce the consumption of power, shorten the time solving fiber, improve and divide From the quality of fiber, and preheating boiling method of the present invention is the digesting technoloy of pressurization, and the most the most key is Boiling temperature.

Boiling temperature

Boiling temperature (DEG C)	Plasticity (0.0001S)
		Without steaming and decocting wood chip (moisture content 60%)	1400
135	3660
		155	4523
175	5501

As seen from the above table, boiling temperature is from 135 DEG C-175 DEG C, and plasticity improves about 50%, when corresponding solution is fine suffered by fiber Mechanical damage reduce, therefore plate intensity improve.On the other hand, boiling temperature can not improve simply, because fibrous raw material is being grown Under the high temperature action of time, pH value declines, and darkens, tendering of fiber, and pliability difference and yield reduce.

2.2 fibers separate.At present, MDF Industry is divided into Mechanical Method and blasting procedure Mechanical Method be divided into heated mechanical method, Chemical mechanical pulping and purely mechanic method, of the present invention is heated mechanical method.

This method of heated mechanical method has two important factors to be elastoplasticity and the External Force Acting frequency of raw material, it addition, Power and wood chip moisture content etc. after unit when solving fine, also can affect the capable of fiber.After the elastoplasticity of raw material, i.e. raw material deformation The restorable time, as recovery time is long, then fiber is easily cut off, External Force Acting frequency: the big then fiber of External Force Acting frequency Two cut-off minor ticks are short, then fiber separation yield and better quality, in actual production, can increase grinding wheel diameter, improve mill Dish rotating speed, changes mill profile of tooth etc..Fiber separation unit pressure and moisture content suitably will process according to the requirement of equipment.

3. applying glue: the fiber defibrator process produced adds glue, can every mechanical property of significantly reinforcing plate, the present invention Used urea-formaldehyde glue, owing in producing, the making of glue and the relations of production are relatively light, the present invention mainly controls glue and discharges Uniformly, the stability improving operation improves glue ratio in plate, and actual production affect glue quality be mainly with Under the impact of several aspects:

3.1 carbamide and the proportioning of formaldehyde

Carbamide and the mol ratio of formaldehyde: 1:1.15

The pH value of 3.2 reaction mediums, reaction temperature and response time terminal point control

1), formaldehyde put into, add sheet alkali, the pH value adjusting mixture is 8.5-8.8, puts into auxiliary agent and U1, and carbamide U1 refers to here The carbamide thrown in for the first time, similarly such as carbamide U2, carbamide U3 etc., carbamide addition is the fibre weight that defibrator process is produced 0.5375%；Adding tripolycyanamide, open gas lift temperature, 70-75 DEG C closes gas, naturally rises temperature to 85-90 DEG C, be incubated 30 minutes, these rank The pH value of section mixture is 6.5-6.6；Described auxiliary agent can use tertiary amines catalyst aid, such as triethylene diamine, triethylamine, front three Base benzylamine；

2), controlling temperature 87-88 DEG C, add formic acid, the pH value adjusting mixture is 4.9-5.1, reacts 8-10 minute；

The pH value slowly adjusting mixture is 4.6-4.8, reacts 80-100 minute at 90-94 DEG C, and viscosity reaches 18.5- 19.5S/B4 33℃。

Adding sheet alkali, the pH value adjusting mixture is 6.8-7.0, puts into carbamide U2, and carbamide addition is that defibrator process is produced The 0.2375% of fibre weight, adds tripolycyanamide, reacts 30-35 minute at 82-88 DEG C, and the pH value of this stage mixture is 6.5- 6.8, viscosity 18-19.5S/B4 30 DEG C；

3), adding sheet alkali, the pH value adjusting mixture is 7.2-7.5, cools to 75 DEG C, puts into carbamide U3, and carbamide addition is The 0.225% of the fibre weight that defibrator process is produced, reacts 30 minutes at 65-70 DEG C, and the pH value of this stage mixture is 7.0；

4), lowering the temperature, add water simultaneously, add sheet alkali at about 45 DEG C, the pH value adjusting mixture is 8.0, and solid ammonium chloride adds water After being diluted to solubility 20%, with pump by it in glue, improve the hardening time of glue.

5) 40 DEG C to transfer glue, by heating paraffin to the liquid of 70-80 DEG C, is added by liquid paraffin at blow-off pipe by pump Enter fiber.

3.3 reaction solution concentrations and raw material quality.

In MDF produces, low viscosity and big permeability are required for glue, because fiber is than particieboard, veneer tool Having bigger specific surface area, so adhesive must be adequately coated fiber surface, proverb is said, fiber is the thinnest, and glue consumption is the biggest. Waterproofing agent, paraffin it be a kind of hydrophobic meltable, soft material, be primarily used to reduce the adsorption of fiber surface, thus Avoid because face absorption water causes board size change and deformation.Popular say, apply paraffin essence and add, to fiber, material of surging exactly, Its Main Function is as follows:

One is space between Partial Blocking fiber, the channel of cut-off moisture transmission.

Two are increased water and fiber bonded area.

4. fiber drying: defibrator process grinds fiber and makes fiber moisture reach 40%-50% plus applying glue, as without dry Dry process fiber is difficult in adapt to follow-up workshop section, at this process section major control baking temperature on the 165-168 DEG C of right side, will not cause tree Fat precuring, thus affect quiet song (MOR) and the stretching (IB) of plate, etc. mechanical property.

4.1 drying modes, being dried is exactly to be become gas phase to evaporate by liquid phase the moisture in fiber, and fiber is at normal pressure Running in pipeline, of short duration with high temperature thermal medium contact, before moisture is not evaporated, the temperature of fiber itself will not steeply rise, Do not have fiber and cross hot injury and the polycondensation of glue and premature cure.

Of the present invention is the formal pneumatic conveying drying of one-level, is guided by aerator by heat and is dried by fiber so that Fiber obtains heat in the duct and is vaporized by moisture, is dried owing to using primary air stream, and drying time is short, thus, Moment notes the change of baking temperature, especially must not superelevation control.

4.2 baking temperatures (are dried inlet temperature 175-180 degree Celsius, outlet temperature 60-65 degree Celsius), and it is to determine fibre Dimension is dried the determiner of quality, and it depends on being dried medium, and of the present invention is with oily gentle heating, fin Group thus hot-air needed for reality heat drying system at short notice.

Dust: it will store a period of time fiber at fiber feed bin after drying, deliver to mat formation through the feeding blower fan batch mixing that dusts Machine, utilizes vacuum pneumatic to realize the thick molding of fiber, then realizes, by sweeping through the material roller and preformer, the forming process that plate is bad.

4.3 vacuum pneumatic molding: fiber delivers to spreading machine through feeding fan, pipe makes fiber stream even decline in a zigzag, and protects Card fiber blanking is uniform, owing in the bottom of guipure of mating formation being under negative swing pendulum force method guides so that fiber is at horizontal direction energy Enough obtain the thickness being more or less the same, go out the slab of shaping box through sweeping through the material roller and by electronic weight-measuring device to adjust the amount of sweeping through the material, make The fiber that through mating formation of slab obtains the density set.

4.4 slab pre-moldings, the slab of basic forming imposes within certain pressure and saw sanction eliminating through preformer Air so that slab compression in bulk, provides condition for transport and line transport and hot pressing, performs place mat, of the present invention is Continuous way belt precompression, mainly by backer roll before and after guide roll, pressurize roller forms, and the slab after pre-molding must be through mitre saw Cut and obtain neat cross section, meet the long width of slab entering hot press.5. hot pressing: it is the most important of MDF manufacture Operation, deposits conclusive effect to product quality and yield, and it is the water under the synergy of heat and pressure, in slab Dividing gasification, evaporation, density increase, adhesive, waterproofing agent redistribution, there are a series of changes in each component in raw material, thus Make between fiber, to form various adhesion.The process making goods reach and to conform to quality requirements.

Key word: the anti-heat pressing process of hot pressing

5.1 hot presses, during current medium and high density fibre panel produces, hot press type, mainly there are two kinds, one is batch (-type) Multi-daylight press, another kind is continuous press, and of the present invention is the former, simply introduces multi-daylight press at this Main one-tenth part:

A simultaneous opening and closing device；B thickness control device；C oil piping system；D installation press such as unloads the goods from the airplane at the equipment.Mainly it is situated between Continue and be closed at and thickness control device.Simultaneous opening and closing device: press, when closing and opening, makes slab exist by it Being obtained in that same displacement when shrinking with aerofluxus, the slab thickness suppressed is uniform.Thickness control device: main by being placed in pressure Rotary encoder on machine and finger gauge composition, rotary encoder is mainly and displacement signal is changed into signal of telecommunication feeding PC, and Being pressurizeed by programme-control press, the operation of decompression, and finger gauge, in order to spacing when Guan Bi of heating platen, to play a kind of safety Protective effect, as worked as dress plate neglected loading, or when slab thickness is not, finger gauge can make the upper and lower two pieces of heating platens of neutral gear, closes at press Avoiding occuring bending and deformation when closing pressurization, protection heating platen is without damage.

5.2 heat pressing process: mainly grasp the work of these hot pressing three elements of temperature, time and pressure thereof about heat pressing process With.

A hot pressing temperature: hot pressing temperature improves the plasticity of fiber, the combination for various keys creates advantage, heat Making the moisture vaporization in slab, thermosetting resin is in of short duration heated time, and owing to friction reduces, mobility increases, favorably In accelerating solidification, in general, hot pressing temperature refers to heating platen temperature, and reality plays a role in theory be slab in Temperature, in general, properly increasing of hot pressing temperature, it can be ensured that hot press performance (as shown in the table)

Here, P (g/cm3) refers to that density, MOR refer to that MOR, 1B refer to tensile property

But hot pressing temperature is too high on the other hand, then plate there will be intensity and resistance to water, the phenomenon of decline.Overall next Saying, the selection of hot pressing temperature, fully to make glue curing, improves mechanical property and is preferred.

B hot pressing pressure, hot pressing pressure mainly has the following aspects effect: 1. overcome the bounce of fibre mat；2. enter One step gets rid of the air in slab, the contact surface between increased fiber and intertexture, ensures at certain model such as moisture content in general Enclosing, preferably select two-stage nitration to pressurize, two-stage nitration pressurization is divided into high pressure and low pressure stage, and high pressure section makes structure of plate slab closely and row's fall air, reaches To thickness of slab requirement, low pressure stage is then moisture evaporation gasification, and adhesive solidifies, the formation of various adhesions between fiber, for The selection of high pressure section is it is also noted that appropriateness, because such as selecting too high pressure, then top layer density is big, and core concentration is little, and compression is caught up with Hurry up, the density contrast of each layer is the most obvious, then mechanical property can decline, and low pressure stage can not be too low, and too low then heat transfer efficiency is low, heat Pressure time lengthening.

C hot pressing time, medium density fibre board (MDF) slab is when hot pressing, though many high-temperatures and pressure, when will want certain Between, the conduction of guarantee heat and the transmission of pressure, to obtain the solidification of sizing material, prepare predetermined density and ideal density distribution Slab products.While ensureing best in quality, hot pressing time is the shortest.Hot pressing time determines and sizing material kind and performance, fiber Quality, mat moisture content, hot pressing temperature, pressure heating mode and slab thickness are relevant, in general, suitably with factors such as density Extending hot pressing time, all favourable to improving the every physical and mechanical property of product, time lengthening during hot pressing, glue can fully solidify.

Saw limit: the purpose on saw limit is to ensure the specification that product is homogeneous, saw blade workshop section especially it is noted that the use of saw blade, saws Sheet to be changed in time, otherwise makes edges of boards pulling force affect edge appearance quality.

Sanding: the slab products surface irregularity after hot pressing, has pre-hardening thickness, and density is low, affects plate performance and plate surface matter Amount, and bring difficulty to secondary operations, solid in order to obtain, smooth plate face, control finished product and meet the requirement of thickness deviation, need Plate face is carried out sanding process.

One is the collocation noting abrasive band model, simultaneously it is noted that charging rate；

Two is that abrasive band should prevent vibration with sander work surface keeping parallelism, in order to avoid plate face produces ripple；

Three is that sanding amount is accrued calculates accurately really, it is ensured that after sand is cut, the symmetry of plate Density Distribution, thickness deviation reaches standard to be wanted Ask.

Sewage disposal:

Dry production MDF is substantially without substantial amounts of industrial wastewater, and it is mainly some squeezing out by feed auger Stopper water mainly uses anaerobic process to process for this type of waste water present invention, and process chart is as follows:

Technique: plant effluent → early stage precipitation → water collecting settling pond → anaerobic pond → air drain → SBR pond → clear water reserviors → fibre Dimension transition → draining.

It is the work that could not do of forefathers that light burnt powder is filled in wood-based plate, and light-burning magnesium powder is that magnesite is through calcining point Solving CO2, size-reduced and formed, owing to CO2 escapes from Ore, therefore light burnt powder has a lot of capillary micropore, by repeatedly real Testing and know, its PARA FORMALDEHYDE PRILLS(91,95) has good adsorptivity, thus greatly reduces formaldehyde release in Midst density wood-based plate.With Time, medium-density plate carries out applying glue before formation, is uniformly sprayed in wood fibre by light-burning magnesium powder, with glue by fiber and light burnt powder phase Connecting, can form one after high temperature extrusion, light burnt powder plays the effect of casting resin wherein.

By experiment, when the parts by weight of light burnt powder are 10～12, the mechanics of the medium-density plate module formed is strong Degree, compared with not adding light burnt powder, has almost no change, and content of formaldehyde is dropped to 8mg/100g by raw sheet 30mg/100g, this plate Content of formaldehyde reaches country's E1 environmental protection standard (E1 is content of formaldehyde≤9mg/100g), can be directly used for family room's interior decoration, dress Repairing material is a kind of environmental protection product.

In the present invention, when the parts by weight of light burnt powder are less than 10～12, PARA FORMALDEHYDE PRILLS(91,95) absorbs and is decreased obviously, and makees reducing cost With also reducing, although but light burnt powder amount is more than when 10～12 highly beneficial to reduction cost, and absorb formaldehyde ability and further enhance. But this sheet material mechanical strength declines rapidly, can not meet rigid requirements, therefore, sheet material mechanical strength requirement is i.e. met, again to first Aldehyde has a good adsorption, plays an important role to reducing production cost simultaneously, and the parts by weight of light burnt powder are 10～12% to be Optimum.Contrast and experiment such as following table:

Light burnt powder activity size is for the impact of formaldehyde absorbing: when understanding light burnt powder activity higher than 200 seconds by experiment, it PARA FORMALDEHYDE PRILLS(91,95) absorbability is decreased obviously, and the module content of formaldehyde now made, more than E1 standard, reaches more than 10mg/100g.Its Reason is Ore because raw burn or burning (during calcining, temperature controls outside 750-1100 DEG C of scope) make its activity decrease, and raw burn is Formation pore is shallower, and the pore that burning is formed results in blockage.Therefore, formaldehyde adsorption ability declines, thus causes product to reach Less than country's E1 environment-friendly products standard.

The key technical indexes such as following table:

Contrast project	Former medium-density plate	Add light burnt powder medium-density plate
			Content of formaldehyde	30mg/100g	8mg/100g
Mechanical Data (compressive resistance)	60KN/c㎡	59KN/c㎡

Claims (6)

1. a light burnt powder makees the environment-friendly type medium-density plate of inserts, it is characterised in that: its composition is that wood is fine by ratio of weight and the number of copies Dimension 70-80, light burnt powder 10-12, Lauxite 7-9, paraffin 0.8-1.2, sheet alkali 0.2-0.3, formic acid 0.2-0.3, ammonia chloride 0.25-0.3, tripolycyanamide 0.15-0.2；Auxiliary agent 0.05-0.08；Described light burnt powder refers to that magnisite stone is through 750- 1100 DEG C of temperature lower calcination resulting materials；Described auxiliary agent refers to tertiary amines catalyst aid.

Environment-friendly type medium-density plate the most according to claim 1, it is characterised in that preparation method comprises the following steps:

(1) chip: pine weedtree material is whittled into the wood chip meeting production specification, separates for fiber and more preferable condition is provided；

(2) defibrator process: the preheated steaming and decocting of wood chip step (1) cut out, mechanical separation draws fiber；Including preheating steaming and decocting, fiber Separation, applying glue；

(3) it is dried: defibrator process grinds fiber and makes fiber moisture reach 40%-50% plus applying glue, controls baking temperature and exists 165-168℃；Also include step of dusting: during fiber drying, send mode by uniform for light burnt powder spray attachment in fibre with blower fan wind Dimension table face；

(4) mat formation: fiber delivers to spreading machine through feeding fan, and ensures that fiber blanking is uniform, goes out the slab of shaping box through sweeping through the material Roller is also adjusted the amount of sweeping through the material by electronic weight-measuring device so that the fiber that slab through mating formation obtains the density set；

(5) hot pressing: the slab of basic forming imposes the air within certain pressure and saw sanction eliminating through preformer so that slab Compression in bulk；

(6) saw limit: the purpose on saw limit is to ensure the specification that product is homogeneous；

(7) sanding: plate face is carried out sanding process

(8) plate embryo sorting；

(9) packing outbound.

Environment-friendly type medium-density plate the most according to claim 2, it is characterised in that in step (1): soft weedtree and hardwood ratio Example is 4:6；Chip dimensions is: long 16-30mm, wide 15-25mm, thick 3-5mm.

Environment-friendly type medium-density plate the most according to claim 2, it is characterised in that in step (2): described preheating boiling temperature 135 DEG C-175 DEG C, digestion time is 3-6 minute；Described fiber separates and uses heated mechanical method；Described applying glue refers to: in defibrator process Organic fiber exit, adds liquid Lauxite in steam glue spraying mode, is attached to fiber surface；Carbamide and first in Lauxite The mol ratio of aldehyde is 1:1.15.

Environment-friendly type medium-density plate the most according to claim 4, it is characterised in that in applying glue step: the pH value of reaction medium, The method of reaction temperature and response time terminal point control is:

1), formaldehyde put into, add sheet alkali, the pH value adjusting mixture is 8.5-8.8, puts into auxiliary agent and carbamide U1, adds tripolycyanamide, open Gas lift temperature, 70-75 DEG C closes gas, naturally rises temperature to 85-90 DEG C, be incubated 30 minutes, and the pH value of this stage mixture is 6.5- 6.6；Described auxiliary agent refers to tertiary amines catalyst aid, such as: triethylene diamine, triethylamine, trimethyl benzylamine；

2), controlling temperature 87-88 DEG C, add formic acid, the pH value adjusting mixture is 4.9-5.1, reacts 8-10 minute；

The pH value slowly adjusting mixture is 4.6-4.8, reacts 80-100 minute at 90-94 DEG C, and viscosity reaches 18.5-19.5S/B4 33℃。

Adding sheet alkali, the pH value adjusting mixture is 6.8-7.0, puts into carbamide U2, adds tripolycyanamide, divides at 82-88 DEG C of reaction 30-35 Clock, the pH value of this stage mixture is 6.5-6.8, viscosity 18-19.5S/B4 30 DEG C；

3), adding sheet alkali, the pH value adjusting mixture is 7.2-7.5, cools to 75 DEG C, puts into carbamide U3, reacts 30 points at 65-70 DEG C Clock, the pH value of this stage mixture is 7.0；

4), lowering the temperature, add water simultaneously, add sheet alkali at 45 DEG C, the pH value adjusting mixture is 8.0, and solid ammonium chloride dilute is to molten After degree 20%, with pump by it in glue, improve the hardening time of glue.

5) 40 DEG C to transfer glue, by the liquid of heating paraffin to 70-80 DEG C, at blow-off pipe, liquid paraffin is added fibre by pump Dimension.

Environment-friendly type medium-density plate the most according to claim 2, it is characterised in that in step (3): drying mode uses The formal pneumatic conveying drying of one-level, is guided heat by aerator and is dried by fiber so that fiber obtains heat in the duct and incites somebody to action Moisture vaporizes, and is dried inlet temperature 175-180 DEG C, outlet temperature 60-65 DEG C, and dry medium uses and dissipates with oily gentle heating Backing group thus hot-air needed for reality heat drying system at short notice；

Dust: this operation is during fiber drying, send mode by uniform for light burnt powder spray attachment in fiber surface with blower fan wind；It A period of time fiber will be stored at fiber feed bin after drying, deliver to spreading machine through the feeding blower fan batch mixing that dusts, utilize vacuum pneumatic Realize the thick molding of fiber, then realize, by sweeping through the material roller and preformer, the forming process that plate is bad.