JPH08229421A - Method and apparatus for grinding and drying cellulosic material - Google Patents

Abstract

PURPOSE: To grind and dry a cellulosic material so as to almost remove the moisture thereof within a short time in a cellusic material grinding process. CONSTITUTION: A cellulosic material predried until water content becomes 30wt.% or less and formed into small pieces with a particle size of 10 mesh or less is thrown in a mixer 80 and shearing heat is generated in the cellulosic material by the shearing force based on stirring impact force generated when the cellulosic material is ground and stirred by a plurality of stirring impact blades 85, 86, 87 to volatilize volatile gas such as steam or wood vinegar gas from the cellulosic material without especially using a heating means. Dry air is supplied into the mixer 80 through an air supply pipe 96 and discharged to the outside from the mixer 80 through an exhaust pipe and a large amt. of the cellulosic material is ground and dried within a short time until water content becomes 0.2wt.% or less.

Description

Detailed Description of the Invention

[0001]

The present invention relates to crushed chips, pulp,
Regarding the method for crushing and drying cellulosic crushed materials such as rice husks and wood powder, more specifically, it is used as a filler, a coloring material, etc. for plastic products such as plastic molded products, plastic sheets, plastic films and paint The present invention relates to a method for crushing and drying a crushed cellulosic material. The cellulosic crushed material is used as a filler for a plastic molded article, for example, a wood-based synthetic board molded by kneading a cellulosic crushed material and a thermoplastic molding material and extruding to a predetermined wall thickness from a molding die. As a filling material for the above, for example, various conductive materials such as an electromagnetic wave shielding material, a radio wave absorbing material, and an antistatic material are used.

[0002]

2. Description of the Related Art Cellulose crushed materials include wood powder obtained by crushing wood, rice grain, bacas, crushed chips and pulp. Regarding the wood flour among the cellulosic crushed materials,
Wood powder obtained by crushing construction waste materials, sawdust and other waste materials from the woodworking process, and other raw materials wood by means of impact, shear, friction, etc., with a crusher such as an impeller mill or ball mill is fluffy. In addition, a large number of elongated wood powder is contained in a fibrous form, the resin material, the solvent, the dispersibility in the solution is extremely poor, and the wood powder is prone to agglomeration during the storage process, especially when mixed with the resin material, It had a drawback of agglomeration.

[0003] A thermoplastic resin molded material and a plastic molded product mainly composed of wood powder are used as a plastic molded product. A thermoplastic resin molded material and a cellulosic crushed product are melted and kneaded by an extruder or the like and extruded from a molding die into a plate material. There is a molded wood synthetic board. When the wood powder is within the range of the usual water content,
When this wood powder is filled in a molding machine together with a thermoplastic resin molding material and heated, a larger amount of steam and wood acid gas than the mixed wood powder is generated, which causes oxidative corrosion of the wall surface in the molding machine and wear of the molding die. Surface roughness of the molded product itself,
It causes the generation of bubbles and cavities and causes various problems in extrusion molding.

In order to avoid such a problem, it was necessary to improve the dispersibility of the wood powder and to volatilize and remove the contained water as much as possible. The removal of the contained water had a significant effect on the volatilization of the wood acid contained in the wood flour.

Although various means have been used for drying wood or wood chips, as will be described later, it is unsuitable for drying wood powder, and conventionally, in order to improve the above-mentioned drawbacks of wood powder, In order to re-pulverize the wood powder by frictional action between the pulverizing balls, a grinding treatment is performed by a mechanical means such as a dry ball mill. Dry ball mill 100
As shown in FIG. 4, the cooling jacket 102 is formed in the peripheral wall of the mill main body 101, and the water supply pipe 108 is connected to the drain pipe 1.
09 always supplies cooling water to the dry ball mill 10
The temperature within 0 is at least 80 ° C or lower, preferably 70
The temperature is kept below ℃.

Further, inside the mill body 101, a stirring bar 10 as stirring means which is rotationally driven by a motor 105.
4 and the stirring bar 104, a large number of crushing balls 103 are arranged in order to generate a grinding action by being stirred and rolled, and the wood flour to be processed, which is the material to be processed, is put into operation from the open top. After the processing is completed, the product can be taken out from the take-out valve 106 through the take-out port 107, and has a so-called batch type.

In the above dry ball mill 100, for example, a dry ball mill of 5.4 liters capacity loaded with 2.4 liters of zirconia-based ceramic crushing balls having a diameter of 3 mm is used, and the particle size is about 0.3 to 1.2 mm. When the sawdust of No. 3 was put into the mill body 101 as the wood powder to be processed and processed for 2 hours, the wood powder to be processed was agitated and milled between the crushed balls 103,
The long fiber-shaped wood powder to be treated is broken or deformed into particles of spherical shape or spherical shape by crushing due to friction, so that it becomes closer to a granular shape, and the angled parts, protruding parts, and cilia of the processed wood powder. The beard part of the shape is removed or deformed, and the whole is arranged in a shape closer to a grain. Further, due to frictional heat generated between the crushing balls 103 or between the crushing balls 103 and the wood powder to be treated, the water is rapidly heated to a necessary temperature to remove water contained in the wood powder. The water content of the wood powder is removed to about 5 wt% and dried by continuing the grinding for a long time.

In addition to the open type dry ball mill described above, the dry ball mill includes an exhaust pipe in which the opening of the dry ball mill is covered with a sealing lid and the sealing lid communicates with the inside of the mill body 101. There is also a closed type dry ball mill configured by arranging an intake pipe. In this closed type dry ball mill, the oxygen concentration in the mill is set to 15% or less, the temperature inside the mill is set to 80 ° C. or lower, an inert gas such as nitrogen gas is supplied from the air supply pipe, and the exhaust pipe is supplied. By discharging the gas in the mill body, the atmosphere in the mill body is replaced with the nitrogen gas, or the nitrogen gas is continuously flowed, and the milling process of the wood powder is operated in an inert atmosphere.

[0009]

When chips and sawdust are directly crushed by means of a conventional dry ball mill or the like mainly for grinding, there are the following problems.

(1) The water content of the wood powder obtained by pulverizing with a dry ball mill is 5 wt% as described above.
Although the wood powder is removed to a certain degree, when the wood powder is filled and heated in a molding machine such as an extruder together with the thermoplastic resin molding material, steam and wood acid gas are generated from the mixed wood powder.

Therefore, the water vapor and the wood acid gas cause the oxidative corrosion of the wall surface in the molding machine, the wear of the molding die, the roughening of the surface of the molded product itself, the generation of bubbles and cavities, as described above. A very strict addition of a neutralizing agent is required, and it has been a problem left to reduce the water content in the wood powder before molding as much as possible.

(2) Since the crushing balls 103 are loaded inside the dry ball mill even if the capacity of the dry ball mill is increased, the amount of crushed wood powder obtained by one treatment operation is, for example, 3 as in the conventional example described above. The operating time of the dry ball mill was extremely small, such as 1 liter, and was long, for example, 2 hours as described above.

(3) Further, when the thermoplastic resin molding material and the wood powder are heated and agitated and mixed, the periphery of each wood powder is covered with the thermoplastic resin molding material, so that the moisture in the wood powder is molded by the thermoplastic resin molding. Since it becomes a state of being confined by the wood, even if it is subsequently dried by a dryer or the like, the water content of the wood flour cannot be lowered. Therefore, this water vapor or wood acid gas is generated in the molding process, resulting in the hometown, poor appearance and deformation of the molded product.

The present invention was developed in order to solve the above problems, and in the process of crushing a cellulosic crushed product, a cellulose crushed product which removes most of the water content in the cellulosic crushed product in a short time. It is an object of the present invention to provide a crushing / drying method and an apparatus.

[0015]

In order to achieve the above object, in the method for crushing and drying the cellulosic crushed product of the present invention, the particle size is 10 mesh or less, preferably 10 to 45.
The cellulosic crushed material formed into small pieces of mesh is ground and stirred by the stirring impact blades 85, 86, 87 without using a heating means, and shearing heat is generated by the shearing force based on the stirring impacting force. It is characterized in that the content of water contained in the cellulosic crushed product is reduced by heat generation and the crushed product is dried.

Further, in the method for crushing and drying the cellulosic crushed material of the present invention, the above-mentioned cellulosic crushed material is agitated by the stirring impact blades 85, 86 and 87 to give a particle size of 30.
The mixture is ground to a mesh, preferably 60 mesh or less, and shearing heat is generated by the shearing force based on the stirring impacting force when the shearing speed of the stirring impacting blade is 900 to 980 rpm. Due to the heat generated by shearing, vaporized gas such as water vapor or wood acid gas is volatilized from the cellulosic crushed product so that the water content of the cellulosic crushed product is 1.0 wt% or less, preferably 0.5 wt% or less, more preferably 0. It is characterized by being dried within 2 wt%.

The rotation speed of the stirring impact blade is proportional to the shearing force based on the stirring impact force on the wood powder. In the present invention, the rotation speed of the stirring impact blade is referred to as "shearing speed".
If the shearing speed of the stirring impeller is too fast, the mixing effect decreases because the wood powder rises due to the centrifugal force of the stirring impeller, and if it is too slow, the heating value due to the shearing force based on the stirring shock force is small and the drying time is long. From the reason that the drying efficiency is lowered, it is preferably 900 to 980 rpm, and optimally 900 to 950 rpm.

Further, the cellulosic crushed material causes a shearing heat generation by a shearing force based on the stirring impact force, and this shearing heat generation causes the water content to be within 30 wt%, preferably within 15 wt%, more preferably within 10 wt%. Preliminary drying is desirable from the viewpoint of further improving the crushing / drying efficiency of the cellulosic crushed product of the present invention.

Further, dry air is supplied to the cellulose-based crushed product in an atmosphere in which shearing heat is generated by a shearing force based on the stirring impact force of a stirring impact blade, that is, into the mixer 80, and the cellulose-based crushed product is in the dry air. Mixer 80 that contains volatile gas such as water vapor and wood acid gas volatilized from
It is particularly desirable to discharge the water to the outside in that steam does not condense on the inner wall surface of the mixer 80 and the cellulosic crushed material is dried more efficiently.

In addition, adding a pigment such as calcium carbonate or titanium oxide as an additive to a cellulosic crushed product such as crushed and dried wood powder causes coloring of the product,
The above additive is preferable in that the wood powder becomes heavier and the rise of the wood powder due to the centrifugal force of the stirring impact blade is reduced, so that the drying efficiency can be improved.

Further, the size of the wood powder to be ground and dried is extremely large when the length, width and diameter are 5 mm or more, and the drying efficiency is slightly lowered when the size is larger than about 3 mm. The particle size is preferably 10 mesh [10
The standard sieve (1st stage) that must pass 0% is 3.
3 mm] or less.

The cellulosic material crushing / drying apparatus of the present invention is an apparatus for crushing / drying the cellulosic material crushed into small pieces having a particle size of 10 mesh or less, preferably 10 to 45 mesh. , A plurality of stirring impact blades that rotate horizontally in the closed container, and an air supply pipe 96 for supplying dry air into the closed container, and steam and wood acid volatilized from the dry air and the cellulosic crushed material. It is characterized in that it communicates with an exhaust pipe 95 for discharging volatile gas such as gas.

A plurality of the stirring impact blades can be arranged at symmetrical positions forming an equal angle with respect to the rotation axis.

Further, the stirring impact blades are formed by a pair of two blades which are symmetrical with respect to the rotation axis, a plurality of the stirring impact blades are overlapped with each other, and each blade has a symmetrical position which forms an equal angle with respect to the rotation axis. It is desirable that the tip end portions of the uppermost two blades are placed at a position higher than the tip end of the rotation shaft in terms of efficient pulverization and drying.

Furthermore, if the number of stirring impact blades is small, the calorific value of the shearing heat generated by the shearing force based on the stirring impact force will be small, and the wood powder will not be dried. Consists of 6 or more blades.

If a scraper that rotates along the bottom of the closed container is provided on the rotary shaft of the stirring impact blade, the cellulosic crushed material on the bottom of the closed container is effectively circulated upward, so that the inside of the closed container is closed. It is preferable in that the cellulosic crushed product (1) is efficiently crushed and dried.

[0027]

The stirring impellers 85, 86, 87 and the scraper 84 are rotated at a high speed, and the untreated wood powder having a particle size of 12 mesh or less and a large water content, for example, a water content of 8.35 wt% is stored in the mixer 80. Throw in. Mixer 80
The wood powder inside is shattered and broken by the shearing force of the stirring impact blades 85, 86, 87 rotating at high speed with a shearing speed of 900 to 980 rpm, and is ground. The amount of frictional heat generated by friction between powders or wood flours (in the present invention, this frictional heat is referred to as “shearing heat”) is improved, and the temperature in the mixer 80 rises without using a heating means. As it rises, a large amount of vaporized gas such as steam and wood acid gas is volatilized from the wood powder,
The water content of wood flour is efficiently reduced. That is, since the wood flour is finely ground by the shearing force based on the stirring impact force, the drying efficiency is improved, and since the wood powder is dried, it becomes easier to grind the wood powder. It is crushed and dried in a short time.

Moreover, when the dry air is supplied into the mixer 80 through the air supply pipe 96, the volatile gas is contained in the dry air and is discharged to the outside of the mixer 80 through the exhaust pipe 95. It is possible to avoid a phenomenon in which water vapor volatilized from the wood powder is condensed on the inner wall surface of the mixer 80 and water droplets drop into the wood powder of the mixer 80, and the wood powder in the mixer 80 is dried more efficiently.

The treated wood flour thus obtained has a water content of 0.2 wt% or less. When this wood powder is filled in a molding machine together with a thermoplastic resin molding material and heated, the generation of water vapor and wood acid gas from the mixed wood powder is eliminated, so that the wood powder obtained in the present invention is used in a conventional molding machine. Oxidative corrosion of the walls of
It does not cause problems such as wear of the molding die, roughening of the surface of the molded product itself, generation of bubbles and cavities.

[0030]

EXAMPLES Examples of the method for crushing and drying wood flour of the present invention will be described below with reference to the drawings.

The grinding and drying of the wood powder of the present invention is performed in the process of grinding the wood powder by the following means.

In FIG. 1, reference numeral 80 denotes a mixer, and a mixer main body 81 is a casing having a cylindrical shape having an opening on the upper surface and having a capacity of 300 liters, and the opening has a raw material such as wood powder in the mixer main body 81. Input port 94
Then, the input port 94 is covered with the openable and closable upper lid 82.
An air supply pipe 96 for supplying dry air is connected to the upper lid 82, and an exhaust pipe 95 for discharging a large amount of steam or wood acid gas generated from wood powder in the mixer body 81 is also connected to the upper cover 82. Further, one outlet 88 is provided on the outer peripheral surface near the bottom surface of the mixer main body 81, a lid 89 for covering the outlet 88 is provided at the rod tip of the cylinder 91, and the outlet 88 is operated by the operation of the cylinder 91. It is openable and closable. A discharge duct 93 communicates with the discharge port 88.

Further, at the center of the bottom surface of the mixer main body 81, a shaft 83 which rotates at a high speed by a rotation driving means of a motor (not shown) having a horsepower of 37 kw (DC) is supported upward in the mixer main body 81. A scraper 84, stirring impact blades 85, 86, 87 in order from bottom to top on the shaft 83
Is mounted and tightened with a tightening nut 92 from the tip of the shaft 83. The shape of each of the stirring impact blades 85, 86, 87 is not particularly limited, but in the present embodiment, it is two blades symmetrical about the axis 83. When three pairs of stirring impellers are stacked as shown in Fig. 1, it consists of 6 blades in total.
Each of the blades is a plane with an equal angle (60
Are overlapped with each other so as to form a degree). When a plurality of stirring impact blades are provided, it is preferable to overlap the stirring impact blades at an angle that is equal to 360 degrees, which is the total number of stirring impact blades, so that the raw materials can be efficiently ground and stirred.

Further, the shape of the stirring impact blade 87 located at the top is bent so that the tip portion of the two blades is higher than the portion attached to the shaft 83, and the tip portion is formed from the tip of the shaft 83. It is placed in a high position. As a result, a shearing force by the stirring impact blade 87 can be applied to the upper layer portion of the wood powder put into the mixer 80, which is a desirable shape in that the wood powder is efficiently ground and dried.

The scraper 84 is rotated by slightly sliding the bottom surface of the mixer body 81 into contact with the mixer body 8.
The raw material in 1 is stirred and circulated upward so as not to stay on the bottom surface, and further, the processed raw material is scraped out so as not to remain on the bottom surface of the mixer main body 81.

[Pretreatment of Wood Flour] Mixer 80 in this embodiment
The wood powder to be put therein is obtained by coarsely crushing construction waste materials, sawdust and other waste materials in the lumbering process and woodworking process into small pieces with a known crusher such as a cutter mill.
The cutter mill includes, for example, a cutter support body that rotates in a horizontal direction by a rotation driving means in a cutter mill main body having a cylindrical shape having an input port for inputting a material to be crushed of the raw material wood,
Three rotary blades are provided in the outer peripheral longitudinal direction of the cutter support so as to form an equal angle of 120 degrees in the rotational direction of the cutter support, and the blade edges of the three rotary blades are located on the same rotation locus. ing. The two fixed blades are fixed to the cutter mill main body through a slight gap with respect to the rotational trajectories of the cutting edges of the three rotary blades, and the inside of the cutter mill main body is charged by the two fixed blades, the cutter support and the rotary blade. And divide it into a crushing room. The clearance between the second fixed blade and the rotary blade is adjusted so that the material to be crushed can be cut into a desired size or crushed in a broad sense.
In the crushing chamber, the two fixed blades are partitioned by a mesh screen so as to surround the circumference of the rotary locus of the rotary blade, and in this embodiment, the screen is a mesh through which small pieces with a side of about 3 mm can pass. It is formed by. The charging port communicates with the charging chamber, and a discharge port for discharging the small amount of wood powder that has passed through the screen is provided at the lower end of the cutter mill body in the crushing chamber.

The cutter mill is not limited to the above-mentioned cutter mill, and for example, like a hard crusher manufactured by Horai Co., Ltd., the rotary shaft of the rotary blade is provided in the horizontal direction, and the screen between the two fixed blades is downward. Some are provided.

Further, the crusher is not limited to the above-mentioned cutter mill, and for example, various mono cutters, shredders, crushers, etc. such as Gainax crusher manufactured by Horai Co., Ltd. or roll crusher manufactured by Nara Machinery Co., Ltd. "Crusher" can be used. The "crusher" is, for example, provided in the crusher main body having an input port for the material to be crushed at the top, two axes that rotate inwardly in parallel with each other, and a plurality of rotary blades are provided at predetermined intervals on each axis.
The three claw blades that mesh with each other on the outer periphery of each rotary blade of each shaft and project on the outer peripheral surface of each rotary blade so as to form an equal angle cut the crushed material into crushed pieces of appropriately large fragments. It is provided. The coarsely crushed material put in from the upper inlet is
Acts when retracting while slitting with a continuously acting shearing force between the outer peripheral edges of the rotating blades that are drawn inward by the claw blades of the two-axis rotating blades that rotate inward with each other and that rotate in mesh with each other It is crushed and cut by the compressive force applied to form crushed pieces. The crushed pieces pass through a screen provided below the biaxial rotary blade and are discharged from a discharge port.

The shape of the wood powder coarsely crushed into small pieces by the above-mentioned cutter mill has an irregular shape, for example, a rectangle or a square with one side of 3 mm or less, or an irregular shape, or a diameter of about 1 to 3 mm and 1 to 3 mm. The shape is rounded into a cylindrical shape of a certain length, and other irregular shapes.

When the wood powder is pre-dried in a drying facility such as a hot air drying furnace (dryer etc.) described later, the size of the wood powder is too small, for example, the average diameter of the largest particles of the wood powder is 10.
If the particles are finer than the mesh, the wood powder will burn with the hot air or be blown away by the hot air. Therefore, in this embodiment, the particle size is about 12 mesh.

The size of the untreated wood powder ground and dried with the mixer 80 is extremely large when the length, width or diameter is 5 mm or more, and when the size is larger than about 3 mm, the grinding and drying efficiency is rather small. Therefore, the particle size is 10 mesh or less, preferably 12 mesh or less, more preferably 1
It is preferably formed into small pieces in the range of 0 to 45 mesh.

In this embodiment, before the wood powder is charged into the mixer 80, a small amount of wood powder coarsely crushed by the cutter mill as described above is used in the above drying equipment to obtain a water content of 8.35 wt.
It was pre-dried to%. In addition, when the waste material is used, if the waste material itself has already been pre-dried to some extent, it is not always necessary to pre-dry using the above-mentioned drying equipment, but the time required for the crushing / drying process should be taken into consideration. For example, the water content of wood flour before being added to the mixer 80 is 3
It is desirable to be within 0 wt%, preferably within 15 wt%, and more preferably within 10 wt%. By the way,
Generally, the normal dry state of wood such as veneer is 12-
It is 15 wt%. However, even if the water content of the wood flour is high, there is no problem in the crushing / drying method of the present invention shown below, and it takes only a proportional processing time depending on the water content of the wood flour. It is not limited to the above-mentioned water content as the pretreatment of.

As the pretreatment of the wood powder, the raw material wood such as the above-mentioned waste wood is finely crushed stepwise by the above-mentioned coarse crusher in a series of steps shown in the following example, and dried by the above-mentioned drying device. It can be processed.

The raw wood is crushed by a crusher into a size of about 12 × 12 mm, the crushed pieces are put into a wood powder storage tank, and the crushed pieces are transferred from the wood powder storage tank to a cutter mill by a conveying device such as a screw. Transport. A magnet is used to remove the metal in the crushed pieces in the conveyance path. The crushed pieces are roughly crushed into a size of about 6 × 6 mm by a cutter mill, and the roughly crushed pieces are sucked by a blower and put into a wood powder storage tank of the next step. Further, the coarsely crushed pieces are conveyed from the wood powder storage tank by a conveying device such as a screw, the metal in the coarsely crushed pieces is removed by a magnet in the conveying path, and the particles are put into another cutter mill and the size of the mesh is about 10 mesh or less. Crush into powder. The wood powder is sucked into a dust collector and pre-dried in the hot air drying furnace of the next step.

[Examples of Milling / Drying Process of Wood Flour] The above-mentioned wood flour (in this embodiment, this pre-dried wood flour is referred to as “untreated wood flour” for convenience) is milled / dried with a mixer 80. The steps to be performed will be described in detail below.

(1) The motor is rotated at a rotation speed of 920 rpm to stir the impellers 85, 86, 87 and the scraper 84.
At a high speed, the upper lid 82 of the mixer 80 is opened, and 23 kg of untreated wood powder having a grain size of 12 mesh or less and a water content of 8.35 wt% is introduced into the mixer main body 81 from the charging port 94 (this The volume is 57.5 liters when the specific gravity of untreated wood flour is 0.4), and TY
2300 kg of -300 (titanium oxide) is charged together.

The temperature inside the mixer 80 when the untreated wood flour was charged was 93 ° C., and the load current of the motor was 86 A.

(2) The stirring impact blades 85, 8 are driven by a motor.
6,87 and scraper 84 rotating speed 920rp
The wood flour and TY-300 (titanium oxide) were stirred by rotating at m for 15 minutes. In addition, this step can also serve as the above-mentioned preliminary drying step.

The temperature inside the mixer 80 was 185 ° C. and the load current of the motor was 60 A 15 minutes after the untreated wood flour was charged.

The rotation speed, that is, the shear speed of the stirring impact blade is 9
Since it rotates at a high speed of 20 rpm, the stirring impact blades 85, 8
Since the shearing force of 6,87 is high, the untreated wood powder in the mixer 80 is impact-ruptured by the shearing force and crushed to a particle size of 30 mesh, preferably 60 mesh or less, more preferably 60 to 120 mesh or less, and The amount of frictional heat generated by friction between the stirring impeller and the wood powder or the wood powder, that is, the amount of heat generated by shearing, is increased, and the temperature in the mixer 80 rises. As the temperature inside the mixer 80 rises, the volatility of vaporized gas such as water vapor and wood acid gas in the wood powder increases.

Since the wood powder is finely ground in the mixer 80, the drying efficiency is improved, and since the wood powder is dried, it has a synergistic effect that it is more easily ground, and a large amount of wood powder is extremely large. It is crushed and dried in a short time.

Further, dry air is supplied into the mixer main body 81 through the air supply pipe 96 from a dry air supply source composed of a compressor or an air blower (not shown) having a dehumidifying device (here, pressure is 0.2 kgf / cm ² ). . A large amount of water vapor and wood acid gas generated from wood powder are contained in the dry air and exhaust pipe 95
Then, it is discharged to the dust collector by a blower (not shown). When the dry air is not supplied into the mixer as described above, the water vapor in the mixer main body 81 is condensed on the inner wall surface of the mixer 80 such as the inner surface of the upper lid 82 to form water droplets and drop to the wood powder below, and the inside of the mixer main body 81 is dropped. It is important to supply and discharge the dry air to the mixer main body 81 because the wood powder cannot be ground and dried efficiently.

Since the wood powder becomes lighter as the steam and wood acid gas volatilize from the wood powder, the load applied to the stirring impeller is reduced, and the load current of the motor at the start of operation is 86 A as described above. However, 6 minutes after the start of operation, 6
It changed to 0A.

If the shear rate of the stirring impact blade is too fast, the mixing effect is reduced because the wood powder rises due to the centrifugal force of the stirring impact blade, and if the shear rate is too slow, it is based on the stirring impact force. The shear rate is preferably 900 to 980, because the amount of heat generated by shearing due to the shearing force is small and it takes a long time to dry and the drying efficiency decreases.
rpm, more preferably 900 to 950 rpm.

When a pigment additive such as titanium oxide is added to the wood powder, the wood powder is colored, and the wood powder becomes heavier so that the rise of the wood powder due to the centrifugal force of the stirring impact blade is reduced. It is desirable because it improves the milling / drying efficiency, but it can be milled / dried without adding an additive such as calcium carbonate or titanium oxide, and is not limited.

Further, in this embodiment, as described above, the stirring impact blades are three in total of three pairs of stirring impact blades 85, 86, and 87, and when the scraper 84 is included, the total is seven blades. When the number is small, for example, when there are a total of three a pair of stirring impact blades 85 and scrapers 84, the amount of shearing heat generation due to the shearing force based on the stirring impact force is reduced, and the wood powder is not efficiently ground and dried. For that reason, it is preferably 5 or more including the scraper 84, and more preferably 7 or more including the scraper 84.

(3) Next, the motor is rotated at a low speed, the cylinder 91 is operated to move the lid 89 to open the discharge port 88, and the scraper 84 rotating at a low speed removes the wood powder in the mixer body 81 from the discharge port 88. It is scraped out to the discharge duct 93 and discharged.

The treated wood powder obtained as described above has an average particle size of 60 mesh and a water content of 0.16 wt%,
As a whole, it is close to the granular shape of powder and has roundness, and the surface is relatively smooth and dense. The treated wood flour thus obtained hardly aggregates with each other, has good dispersibility in a solution, etc., and is suitable as a support base material for pigments and the like.

[Comparison of Untreated Wood Flour and Treated Wood Flour] Treated wood flour obtained by crushing / drying for 15 minutes in the mixer 80 of the above-described embodiment and before crushing / drying treatment The untreated wood powder and the untreated wood powder are respectively put into a closed furnace capable of adjusting the temperature inside the furnace, and the temperature inside the furnace is set to 130 ° C.
Heated for minutes. The changes over time in the in-furnace humidity and the in-furnace temperature at this time are shown in Tables 1 and 2.

It should be noted that the humidity in the furnace hardly changed after the lapse of 5 minutes from the introduction of each wood powder into the closed furnace, and therefore the description thereof was omitted.

[0061]

[Table 1]

Further, the above Table 1 is graphically shown in FIG.

Looking at Table 1 and FIG. 2, the humidity in the furnace 2 minutes and 30 seconds after the untreated wood powder was put into the closed furnace showed a constant value of about 7.8%. It can be seen that most of the water in the untreated wood flour has evaporated.

As described above, the untreated wood flour was mixed in the closed furnace for 3 times.
As a result of heating for 0 minutes, the untreated wood powder weighed 5.059 g when charged into the closed furnace, and the weight after 30 minutes from the charging was 4.669 g.

Therefore, the water content of untreated wood flour is the theoretical value [(5.059 g-4.669 g / 4.669 g) × 1.
00 =] was 8.35 wt%. By the way, since the water content of wood is always expressed on a dry basis, that is, the ratio of the water content to the weight of only wood excluding water (wt%), the same water content (wt) is also applied to the wood flour of this example.
%).

[0066]

[Table 2]

Further, Table 2 above is shown graphically in FIG.

As shown in Table 2 and FIG. 3, the humidity in the furnace after 1 minute 30 seconds has passed since the treated wood powder was put into the closed furnace showed a constant value of about 0.2%. It can be seen that most of the water in the treated wood flour has evaporated.

As described above, as a result of heating the treated wood powder obtained in this example in the closed furnace for 30 minutes, the weight of the treated wood powder when put into the closed furnace was 3.671 g. After 30 minutes, the weight was 3.665 g.

Therefore, the water content of the treated wood flour obtained in this example is theoretical value [(3.671 g-3.665 g /
3.665 g) × 100 =] 0.16 wt%.

[Example of Use of Treated Wood Flour] In the above-mentioned embodiment, the untreated wood flour was crushed and dried by the mixer 80, and then the treated wood flour was discharged from the mixer 80. It is possible to knead the thermoplastic resin molding material and the treated wood powder in the mixer 80 without using heating means without discharging the powder and then charging the thermoplastic resin molding material into the mixer 80.

For example, as in the above-mentioned embodiment, the size is 12 mesh or less and the water content is 8.35 wt.
% Of untreated wood powder was dried with a mixer 80 to a water content of the wood powder of 0.16 wt% and then mixed with a mixer 80.
12 kg of polyvinyl chloride and 12 kg of waste agricultural vinyl film made of vinyl chloride are put therein, and the thermoplastic resin molding material and the treated wood powder are gelled and kneaded in the mixer 80 for 8 minutes and 20 seconds.

In addition to the thermoplastic resin molding material, additives such as urea, calcium carbonate, titanium oxide, other neutralizing agents such as pigments, stabilizers, pigments, etc. can be charged into the mixer 80.

The above-mentioned calcium carbonate brings good dimensional stability to the wood synthetic board extruded by an extruder or the like, and contributes to remarkably reducing expansion and contraction due to temperature change. Deformation and is inexpensive per se.

Further, the titanium oxide has good fluidity and dispersibility in a solution, and can significantly reduce expansion and contraction due to temperature change with respect to a wooden synthetic board extruded by an extruder or the like. It contributes.

The urea is composed of ammonia, phenol, melamine, etc. and serves as a neutralizing agent for wood acid gas.

When the thermoplastic resin molding material and the treated wood powder are kneaded in the mixer 80 as described above, the step of rotating the stirring impact blades of the mixer 80 at a high speed, that is, increasing the shear rate is performed. After that, the volatility of vaporized gas such as steam and wood acid gas from the wood powder is improved, so that the steam and wood acid gas are efficiently vaporized. Therefore, the generation of water vapor and wood acid gas from the mixed wood powder is eliminated, and when the wood powder is filled in an extruder or the like together with the thermoplastic resin molding material and heated and extruded / injection-molded from the molding die, the treated wood powder and "Thixotropy" in which the pressing force increases with respect to the kneading material with the thermoplastic resin molding material and the viscosity of the kneading material decreases.
Occurs. Therefore, this "thixotropy"
The kneaded material in the extruder becomes easy to flow due to the property of
As a result, oxidation corrosion of the wall surface in the extruder due to wood acid gas and wear of the molding die are eliminated, and the surface of the molded product itself is not roughened, and bubbles and cavities are not generated, thus improving the density and strength characteristics of the molded product. be able to.

When the thermoplastic resin molding material and the wood powder are kneaded in the mixer 80, the entire periphery of each wood powder is covered with the thermoplastic resin molding material. Since it is in a state of being confined by the plastic resin molding material, even if it is subsequently dried by a dryer or the like, the water content of the wood flour cannot be lowered.
Therefore, before kneading the thermoplastic resin molding material and the wood powder in the extruder or the mixer 80, it is desirable that the water content of the wood powder be within 1 wt%, preferably within 0.5 wt%. The method and apparatus for crushing and drying wood flour of the present invention can remove most of the water content in wood flour, and is therefore extremely effective and has a wide range of application.

[0079]

Since the present invention is configured as described above, it has the following effects.

(1) A large amount of cellulosic crushed material is crushed in a short time without using heating means due to the shearing heat generated by the shearing force based on the stirring impact force in the process of grinding the crushed cellulosic material. Most of the water content in the cellulosic crushed material could be removed by generating vaporized gas such as steam or wood acid gas from the material. That is, since the wood flour is finely ground by the shearing force based on the stirring impact force, the drying efficiency is improved, and since the wood powder is dried, it becomes easier to grind the wood powder. It could be crushed and dried in a short time. By the way, in the conventional dry ball mill, about 3 liters of the cellulosic crushed material is contained for 3 to 5 w in 2 hours.
Although only about t% could be removed, in the example of the present invention, about 57.5 liters of the cellulosic crushed material could be removed up to 0.16 wt% of water content in 15 minutes.

(2) Since the air supply pipe for supplying the dry air and the exhaust pipe for discharging both the dry air and the volatilized gas are connected to each other in the atmosphere for stirring the cellulosic crushed material by the stirring impact blade, that is, in the mixer. By supplying dry air into the mixer and including vaporized gas such as vaporized steam and wood acid gas volatilized from the cellulosic crushed matter into the dry air and discharging the vapor to the outside, the vapor is kept inside the mixer. Since dew condensation did not occur on the wall surface, the cellulosic crushed material could be dried efficiently.

(3) If the shearing speed of the stirring impact blade is too fast, the centrifugal force of the stirring impacting blade causes the cellulosic crushed material to fly up, so that the mixing effect is reduced, and if it is too slow, the heat generation amount due to the shearing force based on the stirring impact force is generated. However, the drying efficiency is reduced because the drying time is long and the shearing speed of the stirring impact blade is 900 to 980 rpm, and more preferably 90.
Since it was set to 0 to 950 rpm, it was possible to improve the grinding and drying efficiency.

(4) Since additives such as calcium carbonate and titanium oxide were added to the cellulosic crushed product to be ground / dried, coloring was caused by the additive, and the cellulosic crushed product became heavier and the stirring impact was increased. Since the rise of wood powder due to the centrifugal force of the blades was reduced, it was possible to improve the crushing and drying efficiency.

(5) The size of the cellulosic crushed product to be ground / dried is extremely large when the length, width and diameter are 5 mm or more, and the size of the ground product is about 3 mm, the grinding / drying efficiency is slightly lowered. Therefore, it is preferable that the particle size is 10 mesh [100% standard sieve (1 stage)
Was 3.3 mm or less, the crushing / drying efficiency could be improved.

(6) Since the plurality of stirring impellers are arranged at symmetrical positions forming an equal angle with respect to the rotation axis, the cellulosic crushed material can be efficiently ground and dried.

(7) The stirring impact blades are paired with two blades symmetrical about the rotation axis, and the stirring impact blades are superposed on each other, and each blade is symmetrical with respect to the rotation axis. The cellulosic crushed material could be efficiently ground and dried because the tip end portion of the uppermost two blades was placed at a position higher than the tip of the rotary shaft.

(8) Since the scraper rotating along the bottom of the closed container is provided on the rotary shaft of the stirring impact blade, the cellulosic crushed material on the bottom of the mixer is effectively circulated upward, so that The cellulosic crushed material could be efficiently ground and dried.

(9) When the number of stirring impact blades is small, the calorific value of the shearing heat generated by the shearing force based on the stirring impact force is small, and the cellulosic crushed material is not ground or dried. Therefore, the number of stirring impact blades is four. Efficient crushing of cellulosic crushed materials by providing more than 6 blades, more preferably more than 6 blades
It was able to dry.

(10) The cellulosic crushed product of the present invention is
When filled in an extruder together with a thermoplastic resin molding material, heated and extruded from a molding die, there is almost no generation of water vapor and wood acid gas from the mixed cellulosic crushed material, so wood acid gas that has been generated in the past Oxidation and corrosion of the wall surface in the extruder due to the above, the wear of the molding die can be eliminated, and further, the surface roughness of the molded product itself, the generation of bubbles, cavities, etc. can be eliminated, and the density and strength characteristics of the molded product are improved. I was able to.

(11) The property of "thixotropy" is generated in the kneaded material of the cellulosic crushed product and the thermoplastic resin molding material, and the fluidity of the kneaded material in the extruder is increased due to the property of "thixotropy". It is possible to eliminate the oxidation corrosion of the wall surface in the extruder and the wear of the molding die, and it is also possible to eliminate the surface roughness of the molded product itself, the generation of bubbles, cavities, etc., and to improve the density and strength characteristics of the molded product. I was able to improve.

(12) When the thermoplastic resin molding material and the wood powder are once kneaded in the extruder or the mixer 80, since the entire periphery of each wood powder is covered with the thermoplastic resin molding material, the water content in the wood powder is reduced. Since it becomes a state of being confined by the thermoplastic resin molding material, it is impossible to lower the water content of the wood powder even after drying, but the wood powder crushing / drying method and device of the present invention does not reduce the wood powder content. Most of the water inside can be removed, so it is extremely effective.

[Brief description of drawings]

FIG. 1 is an overall front view showing a cross section of a main part of a mixer used in an embodiment of the present invention.

FIG. 2 is a graph showing the data in Table 1.

FIG. 3 is a graph showing the data in Table 2.

FIG. 4 is an overall front view showing a cross section of a main part of a dry ball mill, which is a conventional means mainly composed of grinding.

[Explanation of symbols]

 80 mixer (fluid mixing and kneading means) 81 mixer main body 82 upper lid 83 shaft 84 scraper 85,86,87 stirring impact blade 88 discharge port 89 lid 91 cylinder 92 tightening nut 93 discharge duct 94 input port 95 exhaust pipe 96 air supply pipe 100 dry type Ball mill 101 Mill body 102 Cooling jacket 103 Grinding ball 104 Stirring bar 105 Motor 106 Ejection valve 107 Ejection port 108 Water supply pipe 109 Drain pipe

Claims (12)

[Claims] 1. A cellulosic crushed material formed into small pieces having a particle size of 10 mesh or less is subjected to a stirring impact force to be ground and agitated, and a shearing heat is generated by a shearing force based on the agitation impacting force. A method for crushing / drying a crushed cellulosic material, which comprises reducing the water content of the crushed cellulose material by heat generation and grinding / drying. 2. A particle size of 10 mesh or less, preferably 10.
~ 45-mesh cellulosic crushed material is stirred and agitated to agitate to grind to a particle size of 30 mesh, preferably 60 mesh or less, and the agitation impact blade has a shear rate of 900 to 980 rpm. A shearing heat is generated by a shearing force based on a stirring impact force at a certain time, and the shearing heat generation causes the water content of the cellulosic crushed product to be 1.0 wt% or less, preferably 0.5 wt% or less, more preferably 0. A method for disintegrating and drying a cellulosic crushed product, which comprises drying within 2 wt%. 3. The shear rate of the stirring impact blade is 900-9.
The method for crushing / drying the cellulosic crushed product according to claim 2, which is 50 rpm. 4. The cellulosic crushed material is caused to generate a shearing heat by a shearing force based on the stirring impact force, and the shearing heat generation causes a moisture content within 30 wt%, preferably 15%.
The method for crushing / drying the cellulosic crushed product according to claim 1, wherein the cellulosic crushed product is pre-dried to within wt%, more preferably within 10 wt%. 5. A dry gas is supplied into an atmosphere in which a stirring impact force is applied to the cellulosic crushed material to stir, and vaporized gas such as water vapor and wood acid gas volatilized from the cellulosic crushed material into the dry air. Claim 1, which is discharged to the outside including the
The method for crushing and drying the cellulosic crushed product according to 2, 3 or 4. 6. A cellulosic crushed product containing calcium carbonate,
A pigment, such as titanium oxide, is added as an additive.
A method for crushing and drying the cellulosic crushed product according to 2, 3, 4 or 5. 7. A particle size of 10 mesh or less, preferably 10.
An apparatus for crushing and drying cellulosic crushed material formed into small pieces of ~ 45 mesh, comprising a plurality of stirring impellers that horizontally rotate in a closed container, and supplying dry air into the closed container. Device for crushing and drying cellulosic crushed material, characterized in that an air supply pipe for communicating with an exhaust pipe for discharging both the dry air and vaporized gas such as steam and wood acid gas volatilized from the crushed cellulosic material . 8. The crushing / drying device according to claim 7, wherein the plurality of stirring impellers are arranged at symmetrical positions forming an equal angle with respect to the rotation axis. 9. The agitation impact blade is formed by a pair of two blades symmetrical about a rotation axis, a plurality of the agitation impact blades are stacked, and each blade has a symmetrical position at an equal angle with respect to the rotation axis. 9. The crushing / drying device for cellulosic crushed material according to claim 7, wherein the tip portion of the uppermost two blades is arranged at a position higher than the tip of the rotating shaft. 10. The crushing / drying device according to claim 7, 8 or 9, wherein the stirring impact blade has four or more blades, preferably six or more blades. 11. The crushed product of cellulosic crushed product according to claim 7, 8, 9 or 10, wherein a scraper rotating along the bottom of said closed container is provided on the rotating shaft of said stirring impact blade.
Drying device. 12. The shear rate of the stirring impact blade is 900-.
The crushing / drying device according to any one of claims 7 to 11, which has a speed of 980 rpm, and more preferably 900 to 950 rpm.