JPH0635350B2 - Method for manufacturing lightweight inorganic building materials with excellent frost resistance - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a lightweight inorganic building material having excellent frost damage resistance, and more particularly to a method for producing a lightweight inorganic building material having excellent frost damage resistance by a papermaking method. .

[Prior Art] Conventionally, as a lightweight inorganic building material having excellent frost resistance, a structure in which a large number of fine bubbles are uniformly dispersed in a cement matrix containing reinforcing fibers, fillers and the like has been widely known.

As a means for mixing the microbubbles in the cement matrix, expanded granules made of a thermoplastic resin, for example, styrene expanded particles are uniformly mixed in the cement slurry,
It is known that a building material is molded from this cement mat slurry and then subjected to high temperature autoclave curing, and the foamed particles are melted by the heat during this curing to form fine bubbles in the cement matrix.

[Problems of conventional technology]

However, there is a problem in that the above-mentioned means mainly requires a casting method and cannot be realized by a papermaking method capable of continuous molding.

For example, the cement slurry used in the papermaking method usually has a slurry concentration of about 5 to 6% in order to maintain the dispersibility of the raw materials during the papermaking method and the uniformity of the formation of the papermaking film. When the synthetic resin foam granules were mixed in the slurry of the concentration, the foamed particles floated on the surface of the slurry, and uniform mixing could not be performed at all. Particularly, in the case of styrene foam particles, the apparent specific gravity is smaller than that of the cement slurry, so that the above-mentioned problem is remarkable.

Therefore, it has been almost impossible to manufacture a lightweight inorganic building material excellent in frost damage resistance using synthetic resin foam granules by a papermaking method.

[Problems solved by the invention]

The present invention, in view of the above problems, a synthetic resin foam granules can be uniformly mixed in the cement matrix by a papermaking method, and thus a manufacturing method that enables continuous molding of an inorganic building material having excellent frost resistance. It was made for the purpose of obtaining.

[Technology for solving problems]

That is, according to the method for producing a lightweight inorganic structural building material excellent in frost resistance of the present invention, a cement slurry having a slurry concentration of at least 6% or more, preferably 7.5 to 11% has a diameter of 2 mm.
The following are uniformly mixed with the organic foamed granules, the slurry is drawn up on a molding cylinder to form an inorganic original plate, and then when the original plate is cured, the organic foamed granules are melted at a high temperature condition. It is characterized by being cured by a curing process including autoclave curing.

[Action]

Whether the synthetic resin foam granules mixed in the cement slurry float or not depends not only on the difference in specific gravity between the two, but also on the slurry concentration. Furthermore, the slurry concentration and the particle size of the synthetic resin foam granules influence each other. To meet each other.

That is, if the foamed particles have the same particle diameter, the higher the slurry concentration, the more difficult it is to float, and conversely, the smaller the particle diameter of the foamed particles is, the more difficult it is for a slurry with a constant concentration.

Therefore, the present inventor has conducted an experiment on the relationship between the slurry concentration at which the foaming fluid does not float and the particle size of the foaming fluid, and the results shown in FIG. 1 were obtained.

That is, in FIG. 1, the vertical axis of the graph represents the floating rate of the synthetic resin foam granules in%, and the horizontal axis represents the slurry concentration in%. The particle size is 3 mm (test example) and the particle size is 2 mm (the same). ) Shown is the result of measuring the levitation ratio using a foamed styrene granule having a particle size of 2 mm (same) and a particle size of 1 mm (same).

In addition, in the above test examples, test examples 1 and 2 use spherical particles, and test examples 3 and 4 use crushed particles.

The test method is as follows: Pulp 8 with cement: silica sand ratio 1
By weight, 3 parts by weight of each expanded styrene particle is mixed, and a predetermined amount of water is added to adjust the concentration to a slurry, which is stirred for 3 minutes, transferred to a graduated cylinder, allowed to stand for 3 minutes, and then the weight of the expanded styrene is measured. Then It is calculated from

As is clear from FIG. 1, it was confirmed that when the expanded particles were particles having a diameter of 2 mm or less, they hardly floated when the slurry concentration was about 7% to 11%.

Further, the foamed particles are preferably crushed and irregularly shaped particles rather than spherically shaped particles in order to lower the floating rate.

Incidentally, in the present invention, the reason for setting the upper limit of the slurry concentration to 11% is preferable from the viewpoint of lowering the floating ratio of the expanded particles if the slurry concentration is made thicker than this, but the slurry is too thick and the papermaking cannot be performed well. This is because the quality of the product deteriorates and the subsequent process is adversely affected.

Slurry concentration is 7.5-
It is preferably set to 11%.

If the slurry is made on a molding cylinder to form a film,
During the film formation, the synthetic resin foamed particles are in a uniformly dispersed state, and as a curing step, if the high temperature autoclave curing is performed at the melting temperature of the synthetic resin foamed particles or higher, the resin in the cement matrix melts This makes it possible to manufacture lightweight inorganic building materials with hollow marks and excellent frost resistance.

[Examples] Next, examples of the present invention will be described.

A slurry having a concentration of 7.5% was prepared according to the composition shown in Table 1, and
A plate material having a thickness of 12 mm, a length of 500 mm and a width of 400 mm is manufactured according to a conventional paper-making method, and after being naturally cultivated for 24 hours, the temperature is kept at 180 ° C.
The autoclave was cured for 8 hours, and the cured plate was subjected to 20 cycles of freezing and thawing by specific gravity and ASTM method A. The results shown in Table 2 were obtained.

Further, the swelling rate of 20 cycles of ASTM (method A) was measured for the above-mentioned Examples 1 and 2 with the blending amount of styrene crushed particles being 0 to 3%, and the results are shown in FIG. It was

The swelling rate is It is calculated from

As is clear from FIG. 2, it was found that the freeze damage resistance became more remarkable as the amount of styrene powder particles added was increased.

Further, when the absolute dry specific gravity was measured, the results shown in FIG. 3 were obtained, and it was also found that excellent lightness is exhibited.

[Effect] Since the present invention is configured as described above, it is possible to easily mold an inorganic building material containing lightweight synthetic resin expanded particles even by a papermaking method.

[Brief description of drawings]

FIG. 1 is a graph explaining the operation of the embodiment of the present invention, and FIGS. 2 and 3 are graphs showing the test results of the inorganic building materials obtained by the present invention.

Claims (1)

[Claims] 1. A cement slurry having a slurry concentration of at least 6% or more, preferably 7.5 to 11%, and having a diameter of 2%.
mm uniformly less organic foamed granules, to form an inorganic original plate by making the slurry on a molding cylinder, then when curing the original plate, the temperature conditions under which the organic expanded granules melt A method for producing a lightweight inorganic building material having excellent frost resistance, which is characterized by curing by a curing process including high temperature autoclave curing.