JP2002274969A5 - - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a sound absorbing material having a large number of continuous pores therein and having good sound absorbing performance. It is.

In these production methods, a surfactant and a thickener are added to the raw material slurry. These effects are considered as follows. That is, the transfer resistance between the raw material particles and water between the bubbles is increased to delay the thinning of the foam film, thereby stabilizing the foam film and making it difficult to be broken. As a result, even if adjacent bubbles come into contact with each other, they are prevented from unifying into large closed cells. After adjoining adjacent bubbles in this way to form a foam film between the bubbles, the foam film between the bubbles is completely eliminated by autoclaving, and a porous film having excellent sound absorbing performance including a number of continuous pores. Quality sound absorbing material can be obtained.

The addition amount of the polyoxyethylene alkyl ether sulfate is preferably from 0.1 to 5.0% by weight based on the total weight of the siliceous raw material and the calcareous raw material. When the amount is less than 0.1% by weight , a sufficient bubble stabilizing effect cannot be obtained, so that adjacent bubbles are integrated. On the other hand, if it is more than 5.0% by weight, the amount of the surfactant adsorbed on the surface of the cement particles increases, increasing the hydrophobicity and inhibiting the hydration reaction. Further, when the content is 0.2 to 1.0% by weight, the effect of the surfactant and the cost thereof are optimal.

Further, since the maximum curing temperature during the semi-curing is 75 ° C. or more, the hardness can be obtained from an early stage of the semi-curing. As a result, even if the base material is pulled by the reinforcing material having a large linear expansion inside the semi-cured body, it is difficult for cracks to occur. Occurrence is reduced. In addition, since the crack was generated due to a difference in expansion between the base material and the reinforcing material, the above-described effect can be similarly obtained even when the linear expansion of the reinforcing material is smaller than that of the base material. As the reinforcing material, a rod material such as a reinforcing steel bar or a stainless steel, or a convergence of carbon fiber or aramid fiber can be used .

[0029]
Example 2 46% by weight of siliceous powder as a siliceous raw material, 47% by weight of early-strength cement, 2% by weight of gypsum, and 5% by weight of quicklime as calcareous raw materials. Otherwise, the conditions and method were the same as in Example 1.
Example 3 The temperature of the secondary slurry was adjusted to 50 ° C. by increasing the temperature of the water to be added. Otherwise, the conditions and method were the same as in Example 1.
Example 4 After the secondary slurry was poured into a mold, the atmosphere was set at 55 ° C. and cured. Otherwise, the conditions and method were the same as in Example 1.