JPH04362051A - Treatment of reinforcing fiber for inorganic building material - Google Patents

Abstract

PURPOSE:To effectively utilize waste fine paper by immersing the paper in an alkali soln. under specific conditions and carrying out dehydration. CONSTITUTION:Waste fine paper is immersed in an alkali soln. of pH >=10 heated to 50-100 deg.C, substances hindering the hardening of cement in the paper are leached out by allowing the paper to stand for >=12hr and dehydration is carried out.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of treating inorganic reinforcing fibers for building materials, and more particularly to a method of treating waste paper pulp that makes effective use of it.

0002

[Prior Art] Traditionally, it has been considered essential to add reinforcing fibers to inorganic products whose main component is cement, etc., in order to give them strength.In recent years, the use of pulp fibers has become very popular in place of asbestos fibers as reinforcing fibers. It is widely practiced. By the way, pulp fibers are a cause of large consumption of wood, and their use is gradually being restricted due to forest protection issues, and various attempts have been made to effectively utilize waste paper pulp, which is an industrial waste.

0003

[Problems with the Prior Art] Among the waste papers used as recycled pulp fiber resources, wood-free paper is considered to have good pulp quality and is suitable for use as reinforcing fiber. Starch is often added as a paper strength enhancer or sizing agent, and there is a problem that these additives cannot be used as pulp fibers as they are substances that inhibit cement hardening.
When used, it was only used as an extender for green pulp.

0004

[Problems to be Solved by the Invention] In view of the above-mentioned problems, the present invention provides a method for processing reinforcing fibers for inorganic building materials so that the entire amount of wood-free paper containing cement hardening inhibitors can be used as pulp fibers as reinforcing fibers. This was done for the purpose of providing a method.

[0005]

[Means for Solving the Problems] That is, the method for processing reinforcing fibers for inorganic building materials according to the present invention is to
It is characterized by being immersed in an alkaline solution with a pH of 10 or higher heated to 100°C, and then dehydrated.

[0006]

[Operation] The high quality paper used in this invention is waste such as office paper. This high-quality paper contains a paper strength enhancer and a starch sizing agent, and as mentioned above, it cannot be used as is as a reinforcing fiber for cement compounding. Therefore, the above-mentioned high-quality waste paper is immersed in an alkaline solution with a pH of 10 or higher heated to 50 to 100°C, and left to stand preferably for 12 hours or more to elute the substances that inhibit cement hardening. Therefore, after this treatment, almost no substances that cause curing inhibition remain in the high-quality waste paper, and therefore, even if the entire amount is used as pulp fibers, curing inhibition will not occur. In the above, the reason why the pH value of the alkaline solution is set to 10 or more is because if it is lower than this, starch cannot be sufficiently dissolved.
The purpose of heating to 50°C is to speed up the dissolution rate.
If it is lower than that, dissolution will not occur fast enough, and if the
This is because if the temperature is higher than ℃, the water will boil and become dangerous.

[0007]

[Example] Next, an example of the present invention will be described. Water was added to waste office paper to give a solid content concentration of 4%, and after stirring with a mixer, a sodium hydroxide solution was added to PH1.
The alkalinity was adjusted to 1. This waste paper slurry was then heated to 60°C and held for 24 hours. Thereafter, it was dehydrated to obtain waste paper pulp with a moisture content of 10%. This treated pulp is used as reinforcing fiber, cement 40% by weight,
8% by weight of treated pulp was added to a mixture of 42% by weight of fly ash and 10% by weight of perlite, mixed uniformly, water was added, and a plate with a thickness of 5 mm, width of 45 cm, and length of 90 cm was formed and cured in an autoclave. . As a comparative example,
A test plate was molded in the same manner as in the above example except that the waste paper pulp was simply ground without any treatment. The bending strength of the above Examples and Comparative Examples was measured and the results are shown in Table 1.

[0008]

[Table 1] In Table 1, pulp COD indicates a substitute characteristic for the amount of starch contained in the pulp after treatment.
The COD of the supernatant liquid of the solution was measured.

As is clear from Table 1, it was found that the products treated according to the present invention had excellent strength even though the entire amount was waste paper pulp.

0010

[Effects of the Invention] As explained above, this invention makes it possible to effectively utilize high-quality waste paper, which conventionally was impossible to add as is, contributing to resource conservation and Heat has various effects such as less wasted energy because the heat during autoclave curing of cement products can be used.

Claims (1)

[Claims] 1. A method for treating reinforcing fibers for inorganic building materials, which comprises immersing waste wood-free paper in an alkaline solution with a pH of 10 or more heated to 50 to 100° C., and then dehydrating it.