JPS5814383B2 - Method of manufacturing architectural boards - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing architectural boards, and is a method useful for manufacturing thick architectural boards using calcium silicate as a matrix.

Architectural boards are manufactured by forming a hydraulic inorganic raw material such as cement into a board shape with the addition of water, and curing this uncured board.

In particular, cement has a calcareous content, and silica sand as a silicic acid content is added to the calcareous content at a Cao/Sio2 molar ratio of 0.5.
Use raw materials mixed so that the temperature is ~1.0, and use high-temperature pressurized steam for curing (autoclape curing)
In this case, strong calcium silicate crystals are produced, and strong architectural boards can be obtained.

In this case, the aggregate is usually mixed at a ratio of 20 to 60% by weight.

Conventionally, methods for obtaining the above-mentioned uncured plate-like body include a paper making method, a mold casting method, a dry method, and the like.

However, in the papermaking method, when the laminate of thin films wound around a sheet is cut open and rolled out flat,
Misalignment occurs between the thin film layers, which tends to cause delamination.

This delamination becomes more noticeable as the thickness of the laminate increases.

Therefore, it is difficult to apply it to the production of thick architectural boards with a thickness of 5 to 20 mm.

Furthermore, the mold casting method is a discontinuous method and has a fundamental drawback of poor production efficiency.

In the dry method, dry raw materials are spread on a running belt conveyor,
This is a method in which the dispersed raw material is formed into a layer using leveling rolls, water is permeated into this layer, and compression molding is performed using pressure rolls (this method has been conventionally used in the production of asbestos cement boards).

However, recently, due to the depletion of asbestos resources, the cost of asbestos has increased significantly and it has become difficult to obtain, making it difficult to use asbestos.

For this reason, the use of fibers instead of asbestos and the omission of asbestos are being considered.

In the dry method, if we consider the function of asbestos fibers in shaping the uncured plate-like material, it is possible to promote the permeability of water into the raw material. This has the effect of preventing cracks in the body.

Conventionally, it has been considered to use glass fiber instead of asbestos in the dry method, but this is intended to add strength to building boards after curing, and the above effects have not been taken into account. do not have.

In fact, glass fibers easily slip through uncured raw materials, are not very effective in reinforcing uncured plate-like bodies, have poor water extraction properties, and are not very effective in improving water permeability.

In addition, the use of synthetic fibers in place of asbestos fibers has been considered, but this only applies to materials that are cured at room temperature, such as underwater or natural curing.

In other words, the purpose of using synthetic fibers is to impart strength to building boards after curing, and in autoclave curing, synthetic fibers melt at high temperatures during curing and lose their form as reinforcing fibers. When considering crepe curing, synthetic fibers are excluded.

The present invention provides a method that enables the production of thick architectural boards using a dry method and autoclave curing from a completely different perspective from the conventional method.

That is, imparting moisture permeability to the layered raw material is done by adjusting the particle size of the aggregate, and imparting strength to the uncured plate-like material is left to the addition of pulp and synthetic fibers.

The purpose of adding synthetic fibers is to impart bending strength to the uncured molded product.

Since this synthetic fiber is cured using autoclave curing, it melts during curing.

Therefore, the pores of the porous silicate material, which is a cured material, are made into discontinuous pores due to the molten synthetic resin, and moisture infiltration is prevented, so that cracks due to freeze expansion can be avoided.

The purpose of adding pulp is to impart crack resistance (hair cracks) to the uncured molded body.

The amount of pulp added is limited so that the cured building material passes grade 1 flame retardancy test of JISAI321.

The method for manufacturing a construction board according to the present invention includes passing through a 4-mesh sieve, receiving 20 to 60 weight of fine aggregate whose non-passage amount is within 5% to a 200-mesh sieve, and receiving 1.0 to 60 weight of pulp.
7.0% by weight, organic synthetic fibers from 0.05 to 2.0% by weight, Cao/Sio2 molar ratio within the range of 0.5 to 1.0, and the remainder being a mixture of cement and silica sand. This method is characterized in that the powder is spread on a running belt conveyor, the spread layer is compression-molded using rolls under water permeation, and the molded product is taken out from the belt conveyor and cured by autoclaving.

In the present invention, Boltland cement is commonly used as the cement.

Silica sand has a purity of 90% or more and a Blaine value of 2000 to 4.
000c/L/g is used.

Molar ratio of CaO in cement and SiO2 in silica sand; Cab/
The reason why 8102 is limited to 0.5 to 1.0 is that if it is less than 0.5, sufficient strength cannot be imparted to the board material after hardening.
This is because a large amount of lime remains in the hardened material as free lime, which causes efflorescence.

The reason why we limited the aggregate particle size to 4 mesh all through and the amount that does not pass through 200 mesh to 5% or less (the sieve is JI
If a large amount of 200-mesh fine aggregate (according to the standard sieve specified in SZ8801) is used, the permeability of moisture in the spread raw material layer will decrease, making it impossible for the compact to contain the moisture necessary for the curing reaction. This is because, with large aggregates of 4 mesh or more, the irregularities on the surface of the molded product become noticeable, and the appearance of the surface of the building material inevitably deteriorates.

The average particle size of the aggregate is 500 μm to 1000 μm,
One or a mixture of two or more of hard sandstone, hard limestone, basalt, and andesite as raw stones can be used.

In the present invention, the reason why organic synthetic fibers are added is to impart a desired bending strength to the uncured molded body and to prevent the molded body from bending and breaking when the molded body is taken out from the belt conveyor.

The reason why the amount of organic synthetic fibers added was limited to 0.05 to 2.0% by weight is that below 0.05% by weight, the bending reinforcement effect described above is insufficient, and the organic synthetic fibers will eventually melt. This is because, although it contributes to improving the waterproofness of the porous silicate board, it does not contribute as a reinforcing fiber, and if the weight bearing is 2.0 or more, the strength of the board becomes insufficient.

Organic synthetic fibers include fiber diameter; 1. Polypropylene fibers having a fiber length of 5 to 20 mm are used.

Organic synthetic fibers with a fiber diameter of 1.0 d or less are difficult to produce industrially, and those with a fiber diameter of 10 d or more have low strength.

If the fiber is less than 5 st, the bending reinforcing effect on the above-mentioned uncured plate-like body will be small, and if it is more than 2,011, the fibers will become conspicuously lumped and it will be difficult to uniformly mix them into the 1-ba raw material.

In the present invention, the reason why pulp is added is to impart crack resistance to the uncured molded product and to prevent the occurrence of hair cracks in the molded product when the molded product is taken out from the belt conveyor.

The reason why the amount of pulp added was limited to 1.0 to 7.0% by weight is that below 1.0% by weight, the above-mentioned hair scratch prevention effect is insufficient, and when above 7.0% by weight, the hardened building material This is because it becomes difficult to pass the first class flame retardancy test of JISA1321.

Pulp slurry (softwood, hardwood lingnin, resin content, soda method, sulfite method, sulfate method, etc.)
The center of this pulp is made from a commercially available sheet made from a pulp slurry (pulp slurry that has been dissolved and removed using a chlorine method etc. to make fibrous cellular material), dried to a moisture content of 10% or less, and then crushed by the impact of a high-speed rotating hammer. Fiber length is 1.0-5.5
The center fiber width in ym is 0.02 to 0.041 II.

In the present invention, autoclave curing is conditioned on the ability to generate calcium silicate crystals by causing a hydrothermal reaction between cement and silica sand.

Specifically, using saturated steam of 4 to 15 atmospheres,
-Cure for 6 hours.

The drawings show the manufacturing equipment used in the invention.

In the figure, 1 is a belt conveyor.

Reference numeral 2a denotes a first fluff box, in which the raw material A1 continuously fed from the raw material conveyor 3a is stirred by a blade roll 4a and deposited on the belt conveyor 1.

This deposited raw material is leveled by a spike roll 5a,
Next, the air in the leveling layer is removed by compression with the perforated roll 6a.

The amount of raw material supplied by the first fluff box 2a is 50 to 70% of the total raw material for the final board.

7 is a water trapping device such as a shower or a flow coater;
The raw material layer that has passed through the perforation roll 6a is connected to the water entanglement device 7.
It is moistened with a water content of 5 to 15% by water sprinkling.

2b is a second flannel box, in which the raw material A2 continuously fed from the raw material conveyor 3b is placed on the wet raw material layer by the bladed roll 4bs, leveling roll 5b, perforated roll 7b, etc. in the same manner as above. Formed in layers.

The amount of raw material supplied from the second fluff box 2b is 50 to 30% of the total raw material for the final board.

8 is a water box, which has a curtain-like cloth 81, through which water drips.

The raw material layer that has passed through the perforated roll 7b at the outlet of the 27th rough box contacts the cloth 81 of the water hooks 8, and
1 is moistened with flowing water, resulting in a water content of 5 to 15%.

Next, it is compressed by a bank roll 9 and further cut to a fixed length by a roll cutter 10.

Reference numeral 11 denotes a veneer scattering container, in which an uncured molded plate cut to a specified length is further compressed by a middle roll 12, and veneer (coloring material mainly made of foreign materials) from the veneer scattering container 11 is sprayed onto the surface thereof. .

Reference numeral 13 denotes a granule dispersion container, in which the first babenya dispersion molding plate is compressed again by a front roll 14, and the granules (colored silica sand) from the granule dispersion container 13 are placed on the surface thereof.
are scattered sparsely.

The spread particles are embedded in the veneer layer by the grain roll 15.

Thereafter, the uncured molded plate is taken out from the belt conveyor and, if necessary, is naturally cured for 1 to 3 days.

This natural curing is to give the board the strength necessary when punching it into a product shape (for example, a tile shape).
For example, it is omitted for wall board materials.

Finally, the uncured molded product is transported into an autoclave and cured with high-temperature and pressurized steam.

In the above, moisture permeates into the raw material layer smoothly because the aggregate used in the raw material has a relatively large particle size and little variation in particle size. You can give just the right amount of water.

When there is insufficient moisture, the cured product cannot be given sufficient strength, and when there is excess moisture, the uncured product becomes too soft.
Breakage of the uncured body is unavoidable when the uncured body is taken out from the belt conveyor.

The present invention can eliminate these disadvantages.

Furthermore, the uncured material contains pulp and synthetic fibers and has excellent crack resistance and bending breakage resistance. It does not occur in the body.

Furthermore, even if the cured building material contains pulp, since the amount of pulp is limited, the cured building material passes the JISAI 321 flame retardancy test with first grade.

Furthermore, in hardened building materials, due to the melting of synthetic fibers during curing, the pores of the porous silicate material are made into discontinuous pores by the molten synthetic resin, improving waterproofness. There are no defects even after 100 cycles for the freeze-thaw test.

In fact, samples were created for the following raw material composition (however,
After forming the uncured plate, it was immediately cured in saturated steam at 10 atmospheres for 10 hours (plate thickness was 10 m), and when a JISA1321 flame retardancy test was conducted, all passed the first test and passed ASTM C.
-666 was subjected to a freeze-thaw test, and no abnormality was found even after 100 cycles.

[Brief explanation of the drawing]

The drawing is an explanatory diagram showing an outline of the manufacturing apparatus used in the present invention. In the figure, A1 and A2 are raw materials, 1 is a belt conveyor,
2at2b is a fluff box, 3aj3b is a raw material supply conveyor, 4a, 4b are rolls with blades, 5ay5b is a leveling roll, 6at6b is a perforated spout, 7 is a watering device,
8 is a quarter box, 9 is a pressure roll, 10 is a roll cutter, and 12, 14 and 15 are pressure rolls.

Claims (1)

[Claims] 1 Pass through a 4-mesh sieve, and pass through a 200-mesh sieve with a fine aggregate of 20 to 60% by weight, pulp of 1.0 to 7.0% by weight, and organic synthetic fibers of 0%.
．． 05 to 2.0 weight ratio, Cao/Sio2 molar ratio is 0.
5 to 1.0, with the remainder being a mixture of cement and silica sand, is spread on a running belt conveyor, and compression molded with rolls at the age of the spread, under the penetration of water, and this molded product is formed. 1. A method for manufacturing a construction board, which comprises taking the molded product out from a belt conveyor, curing it by autoclaving, and melting the organic synthetic fibers in the molded product.