KR20020065133A - Method for preparing compressed cellulose reiforcement fiber - Google Patents

Abstract

PURPOSE: A manufacturing method of compression-formed woody pulp reinforcing fiber is provided which is characterized by not generating dust in time to add to cement complex or asphalt, having excellent dispersability because specific gravity is increased, increasing bending strength, bending tenacity, abrasion and impact resistance, controlling cracking and growth of a crack, increasing ability of the cement complex, not slipping down in time to pave with stone mastic asphalt and having excellent effect stabilizing asphalt. CONSTITUTION: The compression-formed woody pulp reinforcing fiber is obtained by a process containing the steps of: dry-dismissing pulp or waste paper to manufacture woody pulp single fiber; injecting the single fiber to a screen conveyor attaching a suction device and a mesh to laminate and to manufacture a sheet; compressing the sheet on a compressing device; and then cutting the compressed single fiber sheet.

Description

Manufacturing Method of Press-molded Wood Pulp Reinforcement Fiber {METHOD FOR PREPARING COMPRESSED CELLULOSE REIFORCEMENT FIBER}

[Industrial use]

The present invention relates to a wood pulp fiber manufacturing method, in particular, concrete, shotcrete, grout, plaster, mortar, cement secondary products, such as cement-based composite fiber, or as a crimped fiber used as a reinforcing fiber added to asphalt A method for producing molded wood pulp reinforcing fibers.

[Prior art]

Cement-based materials (concrete, mortar, shotcrete, cement, secondary products, etc.), widely used in civil engineering and building materials, have local damage due to fragility and brittleness of tensile strength despite many advantages such as durability and economic characteristics. Particularly, cracks due to plastic shrinkage, dry shrinkage, self shrinkage, and heat shrinkage are causing various problems. In order to supplement brittleness, which is a mechanical disadvantage, to secure ductility and increase energy absorption capacity, various fibers are used as reinforcing fibers in cement materials (concrete, mortar, shotcrete, cement secondary products, etc.). The reinforcing fibers include polypropylene fibers, polyethylene fibers, nylon fibers, aramid fibers, polyacrylonitrile fibers, steel fibers, carbon fibers, asbestos, glass fibers, wood fibers and the like.

Among them, wood fiber is a fiber extracted from natural plants and trees, which is excellent in strength and rigidity and can be processed with low energy, or it is advantageous in terms of price and reinforcement of cement-based materials due to its abundant amount. It is suitable as a material. The wood pulp fiber is obtained from conifers and hardwoods, and the fiber itself has high strength and rigidity, which is advantageous for reinforcing the material. The main component of wood pulp fiber is a hydroxyl group, which is excellent in adhesion with the cement matrix, thereby enhancing fracture energy. It is effective in preventing tensile strength, flexural strength, toughness, and impact of materials, and shows the behavior such as stopping of microcracks, fluctuation of crack direction, and pulling out fibers when breaking.

Wood pulp fibers require sponges when used as reinforcing fibers in cement-based materials. Because most wood pulp fibers exist in the form of pulp or paper, sponges made from short pulp fibers are essential for use as reinforcing fibers in cement materials. Sponges require a large amount of water and facilities such as sponges, so that in the manufacture of sheet products such as slits produced by the slurry-dehydration method, mixing equipment in the manufacturing process can be used and is easy to use. In addition, when less water, such as concrete, mortar, shotcrete, etc., it is difficult to use the water sponge, so the pulp or paper is dry pulp fiber bulk by pulverizing, spongy pulp or bulk packed per unit. However, bulk wood pulp fibers are bulky and difficult to weigh and package in the manufacturing process, not only at the construction site or at the same time, but also have a large amount of input error. This is very poor.

On the other hand, conventional asphalt reinforcing fibers, asbestos, glass fibers, cellulose fibers, polyester fibers and the like have been used. These fibers were put into the hot asphalt bitumen in bulk, for example in a bag made of polyethylene (melting point 125 ° C.), where the wrap was melted and dissolved, and the bag was melted. The fibers from were stirred and mixed by a mixer. Such representative reinforcing fiber products include rod-cell of Interfiber, USA, and Bony fiber, Kapjo, USA, of polyester fiber. However, since these fibers are added in bulk, they are dispersed in the bitumen mixture in a heterogeneous state depending on the mixing device. Also, if the change in the amount of the packaging unit and the bitumen mixture does not coincide, it is inconvenient to re-weigh and manually add the fibers. There was a problem that the error of input amount is increased because this is also a working condition at high temperature. In addition, the asphalt reinforcing fiber is used for the flow-resistant asphalt pavement to absorb the flowing asphalt to stabilize the asphalt pavement, but the error of the input amount has a problem of making the asphalt pavement more difficult.

In view of the problems of the prior art, it is an object of the present invention to provide a method for producing press-molded woodpulp reinforcing fibers that are easily squeezed and easily weighed into a cement composite or asphalt.

It is another object of the present invention to provide a method for producing press-molded wood pulp fiber which improves dispersibility when the pressed wood pulp fiber is added to a cement composite material by increasing the specific gravity.

Still another object of the present invention is to provide a method for producing compressed wood pulp fibers that are easily mixed and dispersed by adding to cement composite or asphalt.

It is another object of the present invention to provide a manufacturing method of press-molded wood pulp fiber which can be added to stone mastic asphalt to exert an oil absorption force on asphalt to prevent the flow of asphalt and to stabilize the asphalt pavement. It is.

1 is a photograph of compression molded wood pulp fibers produced by the present invention.

2 is a front view of the specimen of Example 2, Comparative Example 1, Comparative Example 2 and Comparative Example 3.

3 is a side view of the specimen of Example 2, Comparative Example 1, Comparative Example 2 and Comparative Example 3.

[Means for achieving the task]

The present invention, in order to achieve the above object, in the method of producing a press-molded wood pulp fiber,

a) dry pulp of pulp or waste paper to produce wood pulp short fibers;

b) attached to the suction device and the mesh (mesh) to rotate the short fibers at a constant speed

Laminated by means of a screen conveyer to a sheet

Manufacturing;

c) pressing the short fiber sheet in a compression processing apparatus; And

d) cutting the crimped short fiber sheet in a cutting device

It provides a method for producing a press-molded wood pulp fiber comprising a.

Hereinafter, the present invention will be described in detail.

[Action]

The present invention can be added to cement-based materials (concrete, mortar, shotcrete, cement secondary products, etc.) to prevent the increase of flexural strength, flexural toughness and cracking, and to be added to stone mastic asphalt to absorb oil on asphalt. In order to manufacture reinforcing fibers that can prevent asphalt from flowing down and stabilize asphalt pavement, press-molded products are manufactured using dry methods to easily measure and package wood pulp fibers at construction sites. To provide a way.

In particular, a large amount of water and press-molded wood pulp fibers are added to cement-based materials or asphalt without the use of other materials, and a method of manufacturing press-molded wood pulp fibers using a dry method that is well mixed and dispersed. To provide.

Pressed and granulated wood pulp fibers of the present invention is produced by increasing the surface specific gravity (molding specific gravity) to 1.5 to 2.5 by compression molding that the surface specific gravity of conventional pulp fibers is about 1.2 to 1.5. The surface specific gravity depends on the compressive force, and when the surface specific gravity increases, the mixing time when the mixture is added to the cement composite or asphalt is reduced.

Press-molded wood pulp fibers of the present invention dry grinding using graft pulp extracted from hardwood or softwood, bleached or unbleached pulp, such as mechanical pulp, or newspaper or waste paper using a hammer mill, pin mill, refiner, etc. And it is made into fine short fibers by mechanical processing to sponge. At this time, the length of the short wood pulp fibers is 0.01 mm to 8 mm, the thickness is 1 to 80 ㎛, their average length is 1.5 to 3 mm, the average thickness is 35 ㎛.

The wood pulp short fibers dried by using a hammer mill, a pin mill, etc. are sprayed and sucked on the screen conveyor by dry wood pulp short fibers dried by using vacuum pressure to a sheet having a thickness of 1 to 200 mm and a width of 10 to 2000 mm. Prepare in form. Preferably, the spun wood pulp fiber is sprayed by air-blower, and the screen conveyor forming the sheet rotates at a constant speed with a vacuum suction device and a mesh attached thereto. (screen convert) is preferred.

The sponged short fibers may also incorporate mineral admixtures such as clay, kaolin, diatomaceous earth or wollastonite, or mineral fibers into molding aids and reinforcements before being sprayed onto the conveyor. Such clays, kaolin, wollastonite may be excellent in compression moldability of short fibers, and may be incorporated into cement compositions, asphalt, and the like to serve as reinforcing fibers, fillers, specific gravity increasing agents, dispersants, and the like. These may be mixed with single fiber alone, or may be used by mixing. When using these, it mixes in the range of 0.1-50 weight% of the wood pulp reinforcement fiber totally compression-molded. Mixing less than 0.1% by weight has no effect, and mixing more than 50% by weight has no effect of increasing the specific gravity by the amount of the mixture and increasing the dispersibility. In the mixing method, the single fiber bulk may be mixed with a general mixer before spraying, or may be sprayed or mixed with short fibers using a separate spraying device.

Next, the sheet of short wood pulp fibers is compressed to a thickness of 1 to 100 mm and a width of 10 to 2000 mm using a compressor such as a roll or other press. The compressor can be continuously compressed in the case of a roll type, and can be compressed intermittently in the same production line in the case of a press. Pressing pressure is enough to have a uniform shape of the wood pulp fibers short compression compression molding, preferably a pressure of 0.5 ~ 300 kgf / cm ^{2 on} the basis of the surface pressure. Roll type compressors act as linear pressures, and press presses act as surface pressures. If the compression pressure is less than 0.5 kgf / cm ² , it is impossible to manufacture a product that maintains the form, and the aggregated short fibers may be released during cutting, and when pressed to 300 kgf / cm ² or more, it may be added to cement products or asphalt. Difficulty in distribution can occur. This pressing step is used to maintain a constant thickness and shape after compression by its own moisture (about 5% by weight) to absorb and maintain moisture in the air contained in the wood pulp short fibers.

Next, the compressed wood pulp short fiber sheet is cut into 1 to 100 mm in width using a roll-type cutting device, and then cut into 1 to 100 mm in a roll and vertically moving cutter to be finally compressed. Pulp fibers are prepared or cut into diameters of 1 to 100 mm and lengths of 1 to 1000 mm with a punch molding machine to produce compressed molded wood pulp fibers of a predetermined shape. When using a punch molding machine, it is preferable to prepare a punch mold so that the compressed pulp fibers to be produced are conical. After cutting, the compressed wood pulp fibers may swell, so the compression may be repeated. This compression may also have the purpose for smoothing the cutting in the cutting step in the final length direction. The length of the press-molded wood pulp fibers produced may be cut into shorter lengths separately depending on the intended use.

Pressed wood pulp fibers used as reinforcing fibers for cement materials (concrete, mortar, shotcrete, cement secondary products, etc.) have hydroxyl groups on their surface to promote adhesion and dispersion in concrete, and compared with cement particle size. Its small effective diameter makes cement-based materials tight. In addition, the press-molded wood pulp fibers have a relatively high surface area and a large number of fibers per unit area, and thus exhibit excellent functions in suppressing the occurrence and progress of cracking in cement-based materials. The press-molded wood pulp fiber of the present invention is a reinforcing fiber for this, and since only short fibers are aggregated, it is well dispersed when mixed with cement-based materials. Therefore, the press-molded wood pulp fibers of the present invention prepared as described above can be easily mixed with a composition of cement-based materials in a general concrete mixer (forced mixer, ready-mixed concrete mixer, etc.), and when mixed with cement-based materials It is easily broken into fine particles by friction with other materials, and easily dispersed by water, so that the wood pulp short fibers are individually dispersed in cement-based materials.

Press-molded wood pulp fibers using the dry method of the present invention is easier to insert, mix, and disperse into a cement-based material composition than conventional bulk pulp fibers, and is easy to measure and package in a manufacturing process. In addition, even when manufacturing cement products by slurry-dehydration method such as a lot of water-using thread, since the fiber is in the form of a single fiber that is spun down, it is very easy to use as a reinforcing fiber because it is well dispersed without a separate sponge facility. It is also easy to apply to secondary asbestos-free cement products such as In addition, the press-molded wood pulp fibers of the present invention is mixed with the general asphalt composition together with the asphalt composition, and finely broken by friction with other materials of the asphalt material when mixed, and easily decomposed to separate the asphalt reinforced short fibers into the asphalt mixture. Can be dispersed.

Pressed wood pulp asphalt reinforcing fibers using the dry method of the present invention is easy to insert, mix, and disperse into the asphalt composition as compared to conventional bulk asphalt fibers, and is easy to measure and package in the manufacturing process. In addition, there is an advantage that can exhibit the performance of the pure wood pulp fiber that can prevent the flow of asphalt by exhibiting the oil absorption when paving the asphalt and achieve the asphalt pavement stabilization.

The present invention will be described in more detail with reference to the following examples and comparative examples. However, an Example is for illustrating this invention and is not limited only to these.

EXAMPLE

Example 1

(Manufacture of Wood Pulp Short Fiber)

Bleached graft pulp (SSK) extracted from conifers was processed into fine short fibers using a pin mill.

(Suction of short fibers using vacuum pressure)

The fine short fibers are transferred to a storage tank, put into a needle roller attached to a lower portion of the storage tank, and desorbed at a constant speed and a predetermined amount, followed by an air-blower. The sheet was manufactured by laminating fibers by blowing on a screen conveyer which is rotated at a constant speed with a vacuum suction device and a mesh attached thereto by blowing in a furnace. The prepared short fiber sheet was made in the form of a sheet having a thickness of 20 mm and a width of 300 mm, and sheets were continuously produced in the longitudinal direction.

(Primary press using roll type rotary compressor)

The sheet having a thickness of 20 mm and a width of 300 mm is processed into a sheet having a thickness of 7 mm and a width of 300 mm by performing the first pressing by the rotation of the roll in the process of conveying the belt conveyor using a roll-type presser (Daewon Precision Manufacturing). It was. The linear pressure at the roll was 15 kgf / cm ² .

(Compression using roll type rotary hydraulic compressor)

The wood pulp short fibers compressed to a thickness of 7 mm and a width of 300 mm were secondarily compressed to a thickness of 4 mm and a width of 300 mm using a roll-type rotary hydraulic press (manufactured by Daewon Precision Co., Ltd.).

(Step of cutting to width 7 mm using a roll cutter)

When the compressed wood pulp short fiber sheet was moved on the Velk conveyor, a roll-type cutter (manufactured by Daewon Precision) was rotated and cut to a width of 7 mm.

(Cutting to length 30 mm using a cutter)

Finally, the compressed wood pulp short fiber sheet was cut into a length of 30 mm using a cutting machine (manufactured by Daewon Precision Co., Ltd.) to prepare a press-molded wood pulp fiber having a width of 7 mm, a length of 30 mm, and a width of 7 mm. The apparent specific gravity of the press-molded wood pulp fibers was 1.8.

Example 2

(Cutting by punch forming machine)

Wood pulp short fibers are prepared, short fibers are made of suction sheets using vacuum pressure, and primary and secondary compression are carried out using a roll-type rotary compressor, followed by punch molding machine (Daewon Precision Manufacturing: Mold diameter 13 mm, length 25). mm, height 7 mm) using the same method as in Example 1, except that the conical wood pulp fibers having a diameter of 13 mm, a length of 25 mm, a height of 7 mm was prepared by compression wood pulp short fibers. . The specific gravity of the wood pulp fibers produced was 1.8.

Example 3

(Concrete used crimped wood pulp fiber as reinforcing fiber)

(Concrete production)

As shown in the table below, a concrete specimen using wood pulp fibers compression-molded by dry processing method as a reinforcing fiber was prepared. The mixing was followed by conventional concrete mixing methods and no dust of woodpulp fibers was generated during the blending.

(Plastic shrinkage crack test)

The mixture was poured to a size of 500 mm × 500 mm × 75 mm, and the test was carried out in a constant temperature and humidity chamber at a temperature of 28 ° C. at a speed of 3.4 m / sec for 24 hours to rapidly observe the crack state. Plastic shrinkage cracking test by drying was performed. The test results are shown in Table 2.

(Dry Shrink Crack Test)

The mixture was prepared in a ring-shaped specimen as shown in Figures 2 and 3, the test was carried out dry shrinkage crack test to observe the crack width while the specimen was naturally dried at room temperature for 42 days. The test results are shown in Table 3.

(Compressive strength test)

The mixture was prepared into a concrete specimen of 10 cm in diameter and 20 cm in height, and then subjected to a compressive strength test.

(Bending test)

The mixture was prepared from 15 cm x 15 cm x 55 cm concrete specimens and subjected to flexural strength test. The test results are shown in Table 4.

Comparative Example 1

(Concrete without reinforcing fiber)

The concrete specimens were prepared in the same manner as in Example 3, and the concrete shrinkage crack test, the dry shrinkage crack test, and the bending test were performed using the concrete without the reinforcing fibers as shown in the concrete composition shown in Table 1 below. The results are shown in Tables 2, 3, and 4, respectively.

Comparative Example 2

(Concrete with polypropylene fiber as reinforcing fiber)

A concrete specimen was prepared in the same manner as in Example 3 except that a polypropylene mesh fiber having a fiber thickness of 0.1 mm and a length of 19 mm was used as the reinforcing fiber as shown in Table 1, and the plastic shrinkage crack was performed. A test, a dry shrinkage crack test, and a bending test were carried out. The results are shown in Tables 2, 3 and 4, respectively.

Comparative Example 3

(Concrete in which bulk wood pulp fibers are used as reinforcing fibers)

A concrete specimen was prepared in the same manner as in Example 3 except that bulk wood pulp fiber short fibers (manufactured by Deepy, USA) were used as the reinforcing fibers as shown in Table 1, and the plastic shrinkage crack test and drying were performed. Shrink crack test and flexural test were performed. Bulk wood pulp fibers were dusty when blended. The results are shown in Tables 2, 3 and 4.

TABLE 1

division Water-cement ratio Cement (kg / m ³ ) Water (kg / m ³⁾ Aggregate ratio (%) Coarse aggregate (kg / m ³ ) Fine aggregate (kg / m ³ ) Fiber addition amount (kg / m ³ ) Example 3 0.39 380 148.2 39 1100 702 1.2 Comparative Example 1 0.39 380 148.2 39 1100 702 0 Comparative Example 2 0.39 380 148.2 39 1100 702 0.9 Comparative Example 3 0.39 380 148.2 39 1100 702 1.2

TABLE 2

division Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Crack width (mm) 0.02 0.34 0.1 0.05 Crack area (mm ² / m ² ) 1.0 8.5 5.1 2.5

As can be seen from the above results, the wood pulp fiber compressed by the dry processing method can be blended without generating dust when used as a concrete reinforcing material, and has excellent plastic shrinkage crack control effect.

TABLE 3

division Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Crack width (mm) 0.01 1.4 0.7 0.02 Crack area (mm ² / m ² ) One 2 3 1.4

As can be seen from the above results, it can be seen that the wood pulp fiber pressed by the dry processing method has an excellent dry shrinkage cracking control effect.

TABLE 4

division Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Compressive strength (kgf / cm ² ) 529.63 500.21 504.87 520.54

TABLE 5

division Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Flexural strength (kgf / cm ² ) 94.57 78.24 83.97 90.86

As can be seen from the above results, it was found that the press-molded wood pulp fiber through the dry processing method has an excellent strength characteristic effect.

Example 5

(Asphalt packing)

Asphalt water was prepared by mixing and dispersing the compression-molded wood pulp fiber f of Example 2 on a conventional fluid resistant asphalt at a high temperature of 150 ° C., and the asphalt water prepared on the bitumen-coated road. Was paved with 50 mm of thickness. There was no dust at all when the compression molded wood pulp fibers were blended, and no asphalt flowing down when paving the road. Three months after the completion of the road, no plastic deformation occurred in the asphalt.

The press-molded wood pulp fiber produced by the production method of the present invention is free from dust generation when added to cement composites or asphalt, enabling automatic metering and input, and the specific gravity is increased, so that It has excellent acidity, improves brittleness in cement composites, increases flexural strength, flexural toughness, abrasion and impact resistance, and improves the performance of cement composites by inhibiting cracking and growth due to shrinkage resistance. When paving asphalt, such as asphalt, there is no falling down of asphalt, and it is very effective in stabilizing asphalt. In addition, the manufacturing method is automated and can be manufactured more efficiently.

Claims (12)

In the production of compression molded wood pulp fibers, a) dry pulp or waste paper to produce wood pulp short fibers; b) attached to the suction device and the mesh (mesh) to rotate the short fibers at a constant speed Sheets laminated by spraying on a screen converyer preparing to a sheet; c) pressing the short fiber sheet in a compression processing apparatus; And crimped short fibers Cutting the sheet in the cutting device Method for producing a press-molded wood pulp reinforcing fiber comprising a. The method of claim 1, The pulp of step a) is graft pulp extracted from hardwoods or conifers, or mechanical pulp and the waste paper is a newspaper or high paper manufacturing method of compression molded wood pulp reinforcement fiber. The method of claim 1, The wood pulp short fiber of step a) is 0.01 to 8 mm in length, thickness of 1 to 80 ㎛ method of producing pressurized wood pulp reinforcing fibers. The method of claim 1, The b) spraying step of the pressurized wood pulp reinforcement fiber is sprayed further comprises a mineral admixture selected from the group consisting of clay, kaolin (kaolin), diatomaceous earth, and wollastonite. The method of claim 1, The sheet b) has a thickness of 1 to 200 mm and a width of 10 to 2000 mm. The method of claim 1, The pressed sheet of step c) has a thickness of 1 to 100 mm, width of 10 to 2000 mm of the press-molded wood pulp reinforcing fiber manufacturing method. The method of claim 1, The method of manufacturing the press-molded wood pulp reinforcing fiber is the compression pressure of step c) is 0.5 ~ 300 kgf / cm ² based on the surface pressure. The method of claim 1, The cutting of step d) is performed by cutting a wood pulp short fiber sheet press-molded into a width of 1 to 100 mm by a roll-cutting device, and then cut to 1 to 100 mm with a roll and a vertically moving cutter. Method for producing molded wood pulp reinforcing fibers. The method of claim 1, The cutting of step d) is a method for producing press-molded wood pulp reinforcing fibers which are cut by a punch molding machine to produce a cone of 1 to 100 mm in diameter and 1 to 1000 mm in length. The method of claim 1, Method of producing a press-molded wood pulp reinforcing fiber is carried out again after the compression of the step b). The method of claim 1, Method for producing a press-molded wood pulp reinforcing fiber of the compression ratio of the molded wood pulp fiber is 1.5 to 2.5. A compression molded woodpulp reinforcing fiber prepared by the method of claim 1.