JPH0545739B2 - - Google Patents

Description

[Detailed description of the invention]

The object of the present invention is to obtain an external wall fireproof structure that passes the fireproof performance test for external walls equivalent to earth-coated walls according to the Ministry of Construction's Jujutsu Notification No. 487 of 1971. The purpose is to obtain an exterior wall fireproof structure that is excellent in workability and waterproofness, and does not cause cracking or peeling of the mortar layer semi-permanently. Traditionally, the exterior of a house has been finished by applying a waterproof sheet to the surface of the base material, placing lath netting on top of the waterproof sheet, and finally finishing the exterior wall surface by performing plastering, spraying, etc. What is the construction work for this finishing?
Construction that involves applying two coats of mortar and then brushing, or applying spray materials such as sand wall spray material or multi-layer pattern spray material, or paint. However, this kind of finish usually does not have the same fire-retardant performance as earth-coated walls according to the Ministry of Construction's Housing Directive No. 487 of 1971, so it has a major drawback that it cannot be used in areas designated by Article 22 of the Building Standards Act. It was hot. In addition, all the above-mentioned work is on-site work,
Since it is very time-consuming, there has been a demand for improvement. In addition, when a mortar layer is formed on the surface, cracks may appear in the mortar layer due to the difference in expansion and contraction due to changes in temperature and humidity between this mortar layer and the base material.
The tar felt used as a waterproof sheet had poor durability, and over a long period of time water that permeated through the mortar layer would rot the base material. Also,
Since the mortar layer is not waterproof, there was a drawback that water that permeated through the mortar layer could allow moisture to enter through the tar felt joints. Another drawback was that the nails that fixed the base material and lath mesh rusted and oozed onto the mortar surface, contaminating the surface. For this reason, instead of using a waterproof sheet and lath net, a method has been considered in which an inorganic or organic undercoating paint is applied to the surface of the base material and then a mortar layer is formed on the surface. For example, if you use an undercoat paint made by adding ethylene vinyl acetate resin to cement, the alkaline content will corrode and discolor the phenol resin, which is the adhesive for class 1 plywood that is commonly used as a base material, and cause the mortar to deteriorate. It has the disadvantage that it bleeds onto the surface of the layer and contaminates the surface, and organic paints have low adhesion and cannot keep up with the expansion and contraction of the base material due to changes in temperature and humidity, resulting in small cracks in the undercoat layer in that area. The problem was that rainwater could seep in from there. Furthermore, if organic paints were used, they could not be used in areas designated by Article 22 of the Building Standards Act mentioned above. Moreover, in both cases, once the nail heads became rusty, it was impossible to completely prevent this rust from appearing on the surface. The present invention considers a mortar composition as an undercoat layer in order to eliminate the above-mentioned drawbacks, provides unprecedented crack-free performance, and is an external wall fireproof structure using this new material and construction method. The structure is as follows: (1) A mortar composition containing Portland cement, alumina cement, hemihydrate gypsum, polymer dispersion, aggregate, and water as the main components is formed as an undercoat layer on the surface of the base board of the house; A finishing layer consisting mainly of cement with an average thickness of 6 mm or more is formed on the surface, or (2) Portland cement, alumina cement, polymer dispersion, aggregate and water are applied to the surface of the base board of the house. A mortar composition mainly composed of is formed as an undercoat layer, and a finishing layer mainly composed of cement with an average thickness of 6 mm or more is formed on the surface of the undercoat layer. To describe the structure in more detail, the house base board referred to in the present invention relates to a base board for construction, and includes lauan plywood, particle board, hard board, insulation board, calcium silicate board, magnesium carbonate board, There are asbestos cement boards, pulp cement boards, wood wool cement boards, wood chip cement boards, ALC boards, rock wool boards, iron boards, etc. The mortar composition used for the undercoat layer is as follows: (1) 100 parts by weight of Portland cement;
Alumina cement 150-700 parts by weight, hemihydrate gypsum 30
~300 parts by weight, and 100 parts by weight of the total of Portland cement, alumina cement, and gypsum hemihydrate, mixed with 15 to 150 parts by weight of polymer dispersion as a polymer component, appropriate aggregate, and appropriate water. , or (2) for 100 parts by weight of Portland cement,
It is a mixture of 150 to 700 parts by weight of alumina cement, and 100 parts by weight of the total of Portland cement and alumina cement, and 15 to 100 parts by weight of polymer dispersion as a polymer component, an appropriate aggregate, and an appropriate amount of water. be. Here, the mortar composition as the undercoat layer is
Apply and form about 0.5 to 3.0 mm. As a finishing layer containing cement as a main component, for example, there is a cement thick spray material specified in JIS A 6915, which is applied by a spraying operation or the like. Other ingredients include aggregates such as silica sand and anhydrite, slaked lime, dolomite plaster, pigments, and viscosity modifiers. It is also possible to further apply another paint onto the finishing layer made of cement thick spray material for coloring and gloss adjustment. If the average thickness of the finishing layer is less than 6 mm, the object of the present invention cannot be achieved. This average thickness means that it is impossible to achieve a uniform thickness when sprayed, so this method of expression was used.
Therefore, there are some areas where the thickness is only 4 mm and 3
There may be areas where the thickness is only about mm. However, such a place naturally has a small area and there is no problem. When the undercoat layer according to the present invention is formed on the base plate and the finish layer is formed on the outer wall, even if the base plate expands and contracts due to changes in temperature and humidity, the undercoat layer moderates the expansion and contraction, so the finish layer does not crack or peel. It does not occur semi-permanently. In addition, the undercoat layer of the present invention has excellent waterproof properties and has a pH of 11 to 12, so it has excellent rust prevention properties, so it can prevent water that has entered from the outside from penetrating further. This prevents nails exposed on the surface of the base plate from rusting, and even if rust does occur, it prevents the rust from seeping onto the surface of the top coat. Another advantage of the present invention is that the exterior wall of the present invention has passed the fire protection performance test equivalent to that of an earth-coated wall according to the Ministry of Construction's Residential Directive No. 487 of 1971, and can therefore be used in designated areas according to Article 22 of the Building Standards Act. has advantages. Additionally, the exterior finish is extremely simplified. Next, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to the description of the following examples unless the gist thereof is exceeded. In the examples, "parts" and "anun" indicate "parts by weight." Examples 1 to 4 and Comparative Examples 1 to 6 Alumina cement and gypsum hemihydrate shown in Table 1 were mixed with 100 parts of Portland cement,
Further, a mixture of the polymer dispersion shown in Table 1 and 900 parts of silica sand was mixed with the mixture and 0.04 times as much water as the mixture in a mixer for 3 minutes. Next, the kneaded mortar composition was applied to a 12 mm thick plywood board using a porous hand roller.
Form a 0.5 to 0.7 mm thick undercoat layer, then apply thick cement spray material as a finishing layer (an example is "Kikusui Tairotsuku" manufactured by Kikusui Chemical Co., Ltd.)
The exterior walls were spray-painted to create a fireproof structure. The fireproof structure of the exterior wall obtained in this way was subjected to a heating test of an exterior wall equivalent to an earthen wall (test according to the fire prevention standard equivalent to an earthen coated wall according to the Ministry of Construction's Jujutsu Notice No. 487 of 1972). The results are shown in Table 2. Structure 0, which is the same as the external wall fire protection structure used in the above test, was exposed outdoors for 6 months, and the presence or absence of contamination due to rust on the finishing layer was visually observed.
Shown in the table.

【table】

[Table] (a) There shall be no changes such as deformation, destruction, or falling off that are considered harmful in terms of fire prevention. (b) There shall be no ignition of flames that are deemed to be harmful in terms of fire prevention. (c) There shall be no afterflame for 30 seconds or more after the test, and no flame shall remain for more than 1 minute. (d) The temperature on the back side shall not exceed 260℃. (e) There shall be no ignition reaching the back side of any part of the test specimen.

【table】

【table】

Claims (1)

[Claims] 1. For the surface of the base board of the house, 100 parts by weight of Portland cement, 150 to 700 parts by weight of alumina cement, and 30 to 700 parts by weight of gypsum hemihydrate.
300 parts by weight, and 100 parts by weight of the sum of Portland cement, alumina cement, and gypsum hemihydrate,
A mortar composition containing 15 to 150 parts by weight of polymer dispersion as a polymer component, appropriate aggregate and water is formed as an undercoat layer, and a finishing layer mainly composed of cement with an average thickness of 6 mm or more is formed on the surface of the mortar composition. An external wall fireproof structure characterized by: 2. For the surface of the base board of the house, 150 to 700 parts by weight of alumina cement per 100 parts by weight of Portland cement, and 15 to 100 parts by weight of polymer as a polymer component per 100 parts by weight of the sum of Portland cement and alumina cement. A mortar composition containing dispersion, appropriate aggregate, and water is formed as an undercoat layer.
An exterior wall fireproof structure characterized by having a finishing layer mainly composed of cement with an average thickness of 6 mm or more formed on its surface.