KR20040070573A - Construction material composition without using asbestos for pressure extrusion type and its production - Google Patents

Abstract

PURPOSE: An asbestos-free construction material composition for extrusion molding and a construction formed product using the composition are provided, to obtain excellent reinforcing property and processability even without using asbestos. CONSTITUTION: The asbestos-free construction material composition comprises 45-65 wt% of cement; 20-45 wt% of a silica powder; 9-13 wt% of sepiolite; and 0.7-1.7 wt% of a plasticizer. Preferably the sepiolite has a fiber having a length of 2-6 mm and a wet volume of 500-700 ml; and the plasticizer is a mixture of attapulgite clay £(Mg, Al)Si4O10(OH)4H2O| and a methyl cellulose-based compound in the ratio of 1.0 :0.5-0.7.

Description

Construction material composition without using asbestos for pressure extrusion type and its production}

The present invention relates to an asbestos-free extrusion type building material composition and a building molded article using the same.

Cement is an important building material that can be mixed and kneaded together with various performance improving agents and excipients to produce various products with the same strength as rocks when cured in a certain mold.

Therefore, this cement material is used to produce various building materials such as window frames, wall panels, etc. by continuous extrusion type or injection type. Among them, the window frames, wall panels, etc. are used by vacuum extrusion molding method.

In the vacuum extrusion molding method, as shown in FIG. 1, inorganic powder raw materials such as cement and silica powder are charged by automatic weighing in a central control room, and weighed and added to other admixtures such as asbestos and plasticizer (S100),

Cement, quartz stone, asbestos and plasticizers and other admixtures are put into a dry mixer and subjected to dry mixing for about 120 to 180 seconds (S200),

When the mixing is complete, 25-30% by weight of water is added and wet mixed with dry mixing (S300).

When the wet mixing (kneading) is completed is homogeneously mixed in a kneader (kneader) and put into the extruder through the pug screw, vacuum chamber, auger screw, gate and the final die is extrusion molded into various products (S400).

The extruded product is cut into the required length and width while moving to the conveyor belt and then cured in a steam curing tank (S500).

After the first curing, the physical warpage and the surface state of the product is inspected and finally the second cut is cured again in the autoclave (S600).

When the autoclave's high temperature and high pressure curing is completed, it is shipped as a final product.

In this process, asbestos has been used as an optimal additive because of its low price, strong fire resistance, resistance to friction, excellent chemical resistance, and excellent electrical insulation.

Despite these characteristics, however, various studies are being conducted to replace asbestos, as it is pointed out as a scary incurable cause of diseases such as asbestosis, lung cancer and mesothelioma.

Asbestos is used more than 10% of the total ingredients.

As an alternative to asbestos, patent application 46984 of 2000 proposes a method of mixing cellulose fibers, sepiolite and polypropylene fibers instead of asbestos.

In the case of the patent, the use of asbestos was reduced to about 3%, and cellulose fiber, sepiolite, and polypropylene fiber were used to complement the asbestos. However, once extruded, the surface of the extruded product is not uniform and deformation occurs. In particular, polypropylene fiber yarn is dissolved by heat during curing at high temperature and high pressure steam, and thus loses its function as a fiber to form various voids. Therefore, the cured product absorbs moisture due to its rough surface and formation of various pores. When the moisture gets cold, it causes cracking in winter, and water penetration problem occurs in summer. In particular, due to its weak strength, cracks in window frames or wall panels have been pointed out as an important problem of serious post-treatment. Even if all of Sepiolite is used instead of asbestos, half of the physical and chemical properties obtained by the use of asbestos do not appear, so the surface unevenness of the produced product, shape maintenance non-uniformity after extrusion, etc., are almost impossible to ship as a product.

The present invention is to develop a composition for extrusion molding that can secure the same level or more of reinforcement and processability using asbestos without using asbestos itself.

In addition, by using the composition to produce a variety of building materials such as window frames or wall panels to provide a building material replacing the existing asbestos-containing products.

The present invention relates to an asbestos-free cement extruded composition and a building molded article manufactured using the composition, which are not partially replaced asbestos, but eliminate the use of asbestos itself.

In general, the above-mentioned patent application No. 2000-46984 developed a non-asbestos product by using a part of sepiolite and cellulose fibers, pulp, and polypropylene fibers instead of replacing the asbestos and reducing its usage to 3% or less. Aims to develop products that provide the same or better reinforcement as using asbestos, while providing asbestos-free products that completely replace asbestos.

The present invention relates to a composition for non-asbestos cement extruded molded articles composed of 45 to 65% by weight of cement, 20 to 45% by weight of silica, 9 to 13% by weight of sepiolite, and 0.7 to 1.7% by weight of plasticizer.

In the present invention, the cement refers to a general Portland cement series, and when used at 45% or less, it is difficult to exhibit the desired strength and durability after curing, and when more than 65% is blended, the amount of other products used is also the desired molded article. It is difficult to get the characteristics of.

In the present invention, the silica powder is 320 mesh or less, and serves as a role and an excipient to reinforce the strength not provided by the cement. If it is used below 20%, it does not show the purpose of reinforcing function. If it is used for more than 45%, it has strength reinforcing effect, but it lowers the workability and lowers the tensile strength of the product and makes the appearance uneven.

Sepiolite in the present invention is 2 to 6mm in length, wet volume of 500 ~ 700ml of fiber yarn when used less than 9% is difficult to maintain the molding form after extrusion molding, the tensile strength is low. On the contrary, when 13% or more is used, the tensile strength is increased and stable performance is exhibited. In addition, in the case of using the sepiolite less than 2mm in length, the shape of the molded article is not maintained after the extrusion molding, the surface is rough. In addition, the wet volume is lowered to less than 200 and the cracks do not show the desired quality.

In the present invention, the plasticizer is used to maintain the plasticity while maintaining the plasticity while various components are uniformly mixed during general cement mixing, and preferably, methyl cellulose series (MC) is used.

Another feature of the present invention is to replace the expensive MC at the same time by using a combination of the above-mentioned MC-based plasticizers (Ag, Al) Si ₄ O ₁₀ (OH) 4H ₂ O Aterpulgite clay is a porous component with numerous pores of its own, mainly silicate (SiO₂), alumina (Al₂O₃), iron oxide (Fe₂O₃), calcium, magnesium, kali, manganese, titanium, etc. Most preferably, those having a density of 2 to 3. Aterpulgite clay and MC are used in combination of 0.2 to 1.0: 0.5 to 0.7, respectively.

The specific manufacturing example by the above structure is demonstrated.

Preparation Example 1

45% by weight of cement, 30% by weight of silica, 10% by weight of sepiolite, 0.5% by weight of MC, and 0.2% by weight of attapulite clay were mixed and homogeneously mixed, followed by wet kneading by filling the remaining amount with water. The homogeneous kneading was extruded through a screw extruder through a die of a window frame to prepare a molded article having a length of 1 m. The prepared product was placed in an autoclave of 1.2 atm, and cured for 24 hours to prepare samples of 15 cm, 10 cm, and 1 m in length, length, and length, respectively.

The remaining embodiments are described in Table I below. (Unit weight%)

Table I

Composition Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Cement 45 55 60 50 45 50 48 45 65 Silica powder 30 32 40 39 42 40 40 50 20 Sepiolite 10 9 11 12 13 10 12 11 13 MC 0.5 0.7 0.6 0.6 0.7 0.6 0.6 0.7 0.7 Aterpulgite Clay 0.2 0.5 1.0 0.8 1.0 0.9 0.8 0.9 1.3 water 25 30 25 25 30 25 25 20 25

Comparative Example 1

55% by weight of cement, 35% by weight of silica, 3% by weight of sepiolite, 2% by weight of cellulose fiber, 0.1% by weight of polypropylene, and 2% by weight of thickener MC were prepared to prepare samples of the same size under the same conditions as in Example 1. .

Here, cellulose fiber was used wood pulp (mainly paper waste).

The test results of comparing the sample of Comparative Example 10 with the product of Preparation Example 1 are as follows.

Modulus of elasticity (㎏ / ㎠) Tensile Strength (㎏ / ㎠) Absorption rate (%) Moisture content (%) Wet Volume: Sepiolite Sepiolight: Length (mm) Length change rate (%) Frost resistance Preparation Example 1 2050 42 9.8 4.4 670 2 to 6 0.08 X Preparation Example 2 2065 44 9.8 4.3 670 2 to 6 0.078 X Preparation Example 3 2072 45 9.8 4.4 672 2 to 6 0.081 X Preparation Example 4 2074 45.5 9.8 4.5 669 2 to 6 0.082 X Preparation Example 5 2076 45.8 9.9 4.56 672 2 to 6 0.083 X Preparation Example 6 2071 45.4 9.7 4.55 678 2 to 6 0.078 X Preparation Example 7 2067 45 9.8 4.57 688 2 to 6 0.089 X Preparation Example 8 2058 45 9.8 4.53 658 2 to 6 0.84 X Preparation Example 9 2038 44 9.8 4.5 672 2 to 6 0.79 X Preparation Example 10 2052 48 10.1 4.43 668 2 to 6 0.84 X Comparative Example 1 2316 29 11.5 4.9 110 2 or less 0.6 X

* Note : Tensile strength test KS L 5104 (Tensile strength test method for hydraulic cement cement mortar)

Flexural Strength KS F 2403 (Simple Beam Center Point Load Method)

The slope of the elastic region is obtained by dividing the change in flexural load by the length of deflection in the linear modulus .

As shown in the above table, the product according to the composition of the present invention shows a difference of about 6 times in wet volume: sepiolite, and in particular, the tensile strength shows a close difference. Particularly problematic is that in the comparative example, the polypropylene is melted during curing at high temperature (more than 160 degrees) and high pressure, and the tensile reinforcing function as the fiber yarn disappears, causing various problems due to the voids generated therein. In addition, the problem of the East Sea in winter is predicted by the pulp fiber being cured by the use of pulp and the absorption of moisture by the pulp fiber.

In addition, in the case of the comparative example in which the volume change is severe due to the absorbing power of the pulp fiber by using the pulp fiber, a severe problem occurs when used as a window frame exposed outside the winter season.

Sepiolite used in the present invention has a fiber length of 2 to 6mm used to form a mesh structure as the fiber yarns entangled with each other and at the same time kneading extrusion eliminates the extrusion resistance by expansion of the wet volume, and curing the molded state after extrusion It exhibits the same or better strength characteristics as conventional asbestos products by maintaining the effect until it is completed.

Claims (4)

Cement 45 to 65% by weight, silica powder 20 to 45% by weight, Sepiolite 9 to 13% by weight, plasticizer 0.7 to 1.7% by weight composition for asbestos-free extruded molded article. The method of claim 1, Sepiolite is a composition for asbestos-free extrusion molding articles, characterized in that the fiber yarn of 2 to 6mm in length, 500 ~ 700ml wet volume. The method of claim 1, The plasticizer is a composition for use in asbestos cement extruded molding products, characterized in that the mixture is used at a ratio of 0.2 to 1.0: 0.5 to 0.7 Cement 45 to 65% by weight, silica powder 20 to 45% by weight, Sepiolite 9 to 13% by weight, plasticizer 0.7 to 1.7% by weight of the composition for non-asbestos cement extruded molding after dry mixing and wet kneading by adding water and continuous extrusion molding Asbestos-free cement extrusion molded product obtained by steam curing treatment at high temperature and high pressure.