JP2770354B2 - Lightweight cement extrusion products - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a lightweight cement extruded product having applications such as exterior wall materials for houses.

(Conventional technology and problems) To manufacture lightweight cement products by extrusion,
Compounding lightweight aggregate with cement and reinforcing fiber in cement,
The material obtained by kneading the mixture with water is passed through an extruder.

Inorganic foams such as pearlite and shirasu balloon are often used as lightweight aggregates, but these lightweight aggregates are easily broken at the time of kneading or extrusion molding, and it is difficult to achieve sufficient weight reduction. In addition, lightweight aggregates are economically disadvantageous because they are expensive.

On the other hand, there has been proposed a method for producing a building material using a thermoplastic resin foam instead of an inorganic foam for weight reduction, using asbestos or a polypropylene fiber which is a synthetic fiber as a reinforcing fiber, and using a cellulose fiber as a process fiber. (Japanese Patent Publication No. 63-1276). However, fibers are a problem in such methods. Asbestos is regulated for use as a carcinogen, and synthetic fibers such as polypropylene fibers burn at high temperatures and also burn thermoplastic resin foams and cellulose fibers at the same time. The use of asbestos or polypropylene fiber is for reinforcing the matrix and for ensuring handling strength during transportation and construction.

Here, an object of the present invention is to provide a lightweight cement extruded product excellent in noncombustibility even if it contains a flammable material such as a thermoplastic resin foam and a cellulose fiber.

(Means and Actions for Solving the Problems) In order to achieve the above object, the present inventors have conducted various studies on extruded materials using thermoplastic resin foams. By using mica in combination, the moldability during extrusion is excellent, and even without using asbestos or polypropylene fiber, it has sufficient bending strength and impact strength for practical use. It has been found that the fire resistance required as a building material is greatly improved, and the present invention has been accomplished.

Here, mica has heretofore been understood as having a two-sided property as a granular material and a fiber, and it has been considered to utilize its characteristics. Focusing on mica as a planar body that had never been used, we attempted to use it, and because it was considered as one of the alternatives to asbestos in the past, fire resistance,
It has been found that not only the incombustibility can be improved, but also the molding properties and impact resistance of the extruded product can be unexpectedly improved. Especially,
The effect of improving moldability by coexistence with a molding aid compounded in the extruded product is remarkable.

That is, the gist of the present invention is that mica is 2
1 to 5 parts by weight of a thermoplastic resin foam having a spherical shape, 3 to 10 parts by weight of a cellulose fiber, based on 100 parts by weight of an inorganic ceramics powder composed of cement and aggregate containing up to 20 parts by weight,
It is a lightweight cement extruded product which is an extrusion molding of a homogeneously kneaded body in which 0.5 to 5 parts by weight of a molding aid is added and further 35 to 70 parts by weight of water, and which is an autoclaved living body.

This lightweight cement extruded product according to the present invention is excellent in workability such that nails can be directly hit and easily cut by a saw,
Moreover, it has the feature of being excellent in nonflammability and fire protection.

(Operation) Next, the reason why the composition of the extruded product is specified as described above in the present invention will be described in detail.

First, mica is contained in an amount of 2 to 20 parts by weight based on the inorganic ceramic powder. If the content exceeds 20 parts by weight, the bending strength is reduced. Here, the cement is an early-strength Portland cement, ordinary Portland cement, blast furnace cement, and the like, and is not particularly limited.
Use ordinary aggregates such as bentonite. Other inorganic,
Organic lightweight aggregates may be further added.

For thermoplastic resin foam, the practical expansion ratio is
The amount is about 10 to 60, but if the amount is less than 1 part by weight per 100 parts by weight of the inorganic ceramics-based powder (the same applies hereinafter), the effect of reducing the weight or imparting workability is small and 5 parts by weight is used. If it exceeds, the bending strength is greatly reduced. As for the shape, a spherical shape is preferable in consideration of the extrudability of the material.

Cellulose fibers are used for both process fibers and reinforcing fibers, but less than 3 parts by weight will result in insufficient cracking prevention or impact resistance during nailing, and more than 10 parts by weight will be nonflammable. Is a problem.

As a molding aid, methylcellulose, ethylcellulose, carboxymethylcellulose, etc. are used, but if it is less than 0.5 parts by weight, the viscosity required for extrusion becomes insufficient, and the water retention is reduced, and problems such as separation of water during extrusion occur. . On the other hand, when the amount exceeds 5 parts by weight, the substance is an organic substance, so that the incombustibility is reduced, which is economically disadvantageous. It is advantageous to incorporate the molding aid in the smallest possible amount.
In particular, in the present invention, since mica coexists, the moldability at the time of extrusion is better than when reinforced with fibers such as polypropylene fiber. Compared with the case where the amount of the agent is increased, it has the same moldability, but is excellent in nonflammability and fire resistance.

The obtained blend is then added with 35 to 70 parts by weight of water, uniformly kneaded to obtain a homogeneously kneaded body, and then molded using a suitable known extruder. If the amount of water is less than the above range, the extrudability is insufficient, while if the amount is too large, not only the moldability but also the strength is insufficient.

The main purpose of autoclaving an extruded product obtained by extrusion-molding these compositions to obtain an autoclave-cured body is to develop strength at an early stage and to enhance dimensional stability.

The thus obtained lightweight cement extruded product according to the present invention has not only excellent fire resistance and nonflammability, but also excellent moldability and impact resistance.

Next, the present invention will be described more specifically with reference to examples.

Example Table 1 shows the compositions of Examples 1 to 3 and Comparative Examples 1 to 8 in terms of weight ratio. These raw materials were blended at a predetermined ratio, mixed and kneaded with a mixer, and passed through an extruder. 200mm wide, 12m thick
m flat plates were formed. After 24 hours air curing,
Autoclave curing was performed at 80 ° C for 5 hours.

 Each performance survey was performed as follows.

The bending strength test was performed by three-point bending in which the size of the test piece was 200 mm in length × 50 mm in width × 12 mm in thickness in the direction of the long side in the extrusion direction, and the bending span was 160 mm.

The nailability is 200 mm long x 200 mm wide x 12 mm thick.
mm, and nails (diameter 30 mm x 30 mm)
2.3mm) directly, and if there was no crack reaching the end, it was judged as pass.

 Sawability was evaluated by the ease of cutting with an electric circular saw.

The weight drop impact is shown in Fig. 1 as the test procedure.
Nail a 200mm wide flat plate 12 into a 450mm span wood frame 12,
At the center, a 1.0 kg weight was dropped from a height of 1.5 m, and the occurrence of cracks was observed.

The nonflammability was evaluated according to the base material test of JIS A1321 “Test method for flame retardancy of building interior materials and construction methods”, and those having a furnace temperature of 800 ° C or less were evaluated as good.

The evaluation of fire resistance was carried out with reference to JIS A1301 "Method of arson test of wooden part of building". As shown in the schematic side view in FIG. 2, the test piece was prepared by processing a flat plate 20 and nailing both ends to wood so as to have dimensions of 470 mm × 470 mm. Using a simple test furnace according to the test procedure shown, the specimen 32 was heated with a gas burner 30 until the front surface of the specimen 32 reached 840 ° C., and evaluated based on the temperature of the back surface 34 and the occurrence of cracks. In other words, according to the JIS standard, those having a back surface temperature of 260 ° C. or less and having no deformation, destruction, or falling off which are harmful to fire prevention were judged as good, and the others were judged as defective.

The results are summarized in Table 1. Examples 1, 2, and 3 have good nailing properties, excellent impact resistance, and excellent nonflammability and fire resistance.

Comparative Example 1 is inferior in nonflammability and fire resistance due to a small amount of mica. Comparative Example 2 has a low bending strength because mica is as large as 30 parts by weight. In Comparative Example 3, since the thermoplastic resin foam was as large as 6 parts by weight, the specific gravity was small, and the bending strength was low. In Comparative Example 4, since the thermoplastic resin foam was small, the specific gravity was high, the nailing property was poor, and the cutting property with a saw was poor. Comparative Example 5 is inferior in nonflammability and fire resistance because of a large amount of cellulose fibers. Comparative Example 6 was poor in nailing performance because of a small amount of cellulose fiber,
Also, the impact resistance is poor.

In Comparative Examples 7 and 8, polyprolene fibers were mixed instead of no mica, and the ratio of the extrusion aid was small in Comparative Example 7 and large in Comparative Example 8. As a result, in Comparative Example 7, although the extrusion speed was low, the surface unevenness was large. Incombustibility and fire resistance are poor. On the other hand, Comparative Example 8
Since the extrusion aid has been increased, the extrusion speed has increased,
The surface irregularities were also reduced, and good molding became possible. However, the nonflammability and fire protection are insufficient.

Here, when Comparative Examples 7 and 8 are compared with Example 1 of the present invention, the moldability is further improved by adding mica according to the present invention, and the same degree of moldability is obtained as shown in Comparative Example 8, Obtained only when 1.7 times the amount of molding aid is added. This unexpected action and effect of mica in the present invention is also notable because methylcellulose as a molding aid is expensive.

(Effects of the Invention) As described in detail above, according to the present invention, a lightweight cement product having good nailing properties and cutting properties with a saw, and having excellent nonflammability and fire protection properties can be obtained.

[Brief description of the drawings]

Fig. 1 is a schematic explanatory view of a test procedure of a weight drop impact test; Fig. 2 is a schematic side view of an extruded material flat plate for a fire prevention test; and Figs. 3 (a) and (b) are fire prevention tests. It is the side view and front view which respectively outline a situation. 10: wood frame, 12: flat plate 20: flat plate, 30: gas burner 32: test specimen, 34: back side

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akira Miyoshi 1-3-1 Otemachi, Chiyoda-ku, Tokyo Sumitomo Metal Industries, Ltd. (72) Inventor Junichi Mizuno 12 Shiodomecho, Minato-ku, Nagoya-shi (58) Field surveyed (Int. Cl. ⁶ , DB name) C04B 38/00-38/10

Claims (1)

(57) [Claims] 1. A spherical thermoplastic resin foam of 1 to 5 parts by weight and a cellulose fiber of 3 to 3 parts by weight based on 100 parts by weight of an inorganic ceramic powder composed of cement and aggregate containing 2 to 20 parts by weight of mica. Extrusion molding of a homogeneously kneaded body in which 〜10 parts by weight, 0.5 to 5 parts by weight of a molding aid, and 35 to 70 parts by weight of water are further added.