JPS62288149A - Manufacture of excelsior cement board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention <Industrial Application Field> The present invention is based on the method of press-molding a mixture obtained by kneading wood materials such as wood chips and wool, cement, and water. The present invention relates to a method of manufacturing a wood cement board by curing and hardening, and more specifically to a method of manufacturing a wood cement board in which a metal compound is mixed into kneading water so that the cement hardens quickly.

<Prior Art and its Problems> A method for producing a wood cement board is well known, in which a mixture obtained by kneading a wood material, cement, and water is pressed and molded, and then cured and hardened to form a board.

However, in the production of such wood cement boards, there is a problem in that the hardening of the cement is inhibited by components extracted from the wood materials used, and as a result, the strength of the wood cement boards is significantly reduced.

In order to deal with these problems, in the past, the tree species used as wood materials were selected, that is, those with fewer wood extracts were used, but it is difficult to stably obtain such high-quality wood materials. At present, this poses significant difficulties and also leads to price increases.

Methods have also been proposed in which a fast-setting cement, a super-fast-setting cement, a thermosetting cement, or the like, which has a fast hardening speed, is used as the cement. This is based on the idea of allowing cement to harden before the above-mentioned wood extract components inhibit cement hardening, but in this case as well, it is possible to completely suppress the hardening inhibition caused by wood extract components. This will reduce the strength of the wood cement board.

Additionally, these types of cement are expensive and less economical.

Several attempts have been made to suppress the inhibition of cement hardening caused by wood extract components. It is presumed that this inhibition of cement hardening due to wood extracted components is due to harmful components extracted from wood materials being eluted into cement slurry water during kneading and inhibiting cement hardening. However, since the specific mechanism has not yet been elucidated, all conventional solutions have been fragmentary and have not provided a fundamental solution. Methods have been proposed in which wood is pretreated with wood or water glass, but these methods have not always been sufficiently effective.

Also known are methods in which wood materials are pretreated with a sulfate such as magnesium sulfate or calcium sulfate and a carboxylic acid, and a method in which wood materials are pretreated with an aluminum salt of a strong acid and an acetate. Although these are effective methods for preventing the elution of extracted components from wood materials, the process of pre-treating the wood materials is time-consuming and complicated; This method has disadvantages from a practical and economic point of view, such as the need to use a mixture of substances.

Means for Solving the Problems> Apart from the technical field to which the present invention pertains, the present inventor has also discovered that in plywood formwork, components eluted from wood inhibit the hydration reaction of the debris and cause poor curing. As a result of various studies on this phenomenon, we found that extracted components such as water-soluble cellulose, lignin, tannin, humic acid, and sugar contained in wood are mixed with cement by the water in the cement slurry. It dissolves at the interface, and these extracted components combine with Ca'', K'', and Na'' released from the cement to form salts.
It has been found that as the cement particles are covered with this salt, the subsequent hydration reaction of the cement is suppressed. In other words, normally cured mortar dry matter contains large amounts of 2SO-, Na25On, and Ca(OH)z, but in the case of poorly cured mortar, the amount of these mixed together decreases, resulting in a significant degree of poorly cured mortar. In mortar, these were hardly present, and instead, a lot of ettringite was found. This is because S04. Na25O,.

N(L”, which should be crystallized as Ca(OH)2)
* is adsorbed or chemically combined with the above extracted components eluted from the wood to form a complex salt, so it cannot be crystallized, and it is presumed that at that time, the excess S04'- crystallized into ettringite. .

Based on the above findings, we have repeatedly considered from a chemical standpoint the means to prevent wood extract components from combining with free ions from cement to form complex salts. By pre-bonding with metal ions that generate highly stable complex salts,
It has been found that wood extract components can more stably chelate with the metal ions, thereby preventing binding with free ions, and thereby preventing inhibition of cement hardening. A patent application was filed on April 18, 1986 (Japanese Patent Application No. 89246/1989) for a plywood whose surface at least on one side was coated or impregnated with a powder or aqueous solution of a metal compound.

The present invention was created to apply this technical concept to wood cement boards. After kneading wood materials, cement, and water to form a mixed mat, the mixed mat is pressed and formed, and then cured. An object of the present invention is to provide a method for producing a wood cement board, which is characterized in that a metal compound that combines with wood extract components to form a highly stable complex is mixed into kneading water when the wood cement board is produced by hardening. It is something.

Preferably, the metal compound is added as an aqueous solution to the kneading water, and this is added to the mixture of wood material and cement and kneaded.

The gold H compound used in the present invention is a compound that combines with extracted components such as cellulose, lignin, tannin, and sugars in wood materials to form a highly stable complex.
The present invention combines wood extract components that are about to be eluted into cement slurry water from wood materials with metal ions of a metal compound in advance, thereby inhibiting the bonding of the wood extract components and cement free ions and the curing of cement based on this. Therefore, the metal compounds used elute metal ions that are soluble in water and have higher stability than free cement ions, and combine with wood extract components to form poorly soluble complex salts. In other words, the extracted components to be eluted from the wood material come into contact with and combine with the metal compounds mixed in the water in the slurry at the interface with the cement slurry, and the water in the slurry It creates a chemically stable complex salt that will not be eluted or subsequently eluted into water, alkaline water, etc. For example, one or two selected from sulfides, chlorides, or hydroxides of iron, copper, zinc, lead, aluminum, etc.
The 7 woody materials that can be used alone, in combination, or in a mixture include wood chips, wood wool, and the like.

Portland cement is usually used as the cement. Of course, ultra-fast hardening or fast-hardening cement I ~ or thermosetting cement may be used, but according to the method of the present invention, the adverse effects of inhibiting cement hardening due to components extracted from this material can be sufficiently suppressed. In particular, there is little need to use these expensive cements.

In addition, in the method of the present invention, since the metal compound is mixed into the cement mixing water, as described above, the metal compound comes into contact with the wood material at their interface to form a complex salt, and the extracted components from the wood material. At the same time, the metal compound can act as a cement hardening accelerator. In particular, Zn.

Sulfuric acid compounds of metals such as Pb and Cu are known as quick-setting agents that promote the aqueous phase reaction of cement I-.

The mixture thus obtained is made into a mixed mat shape using a forming device, then made into a standard size, compacted, and further cured to obtain a wood cement board according to the present invention.

In producing wood cement boards, the metal compound mixed in the mixing water comes into contact with wood materials such as wood chips and wool, and combines with components extracted from the wood material at their interface to form stable complex salts. form. Therefore, no bonding occurs between these wood extracted components and free ions from cement, and a wood cement board with excellent strength can be obtained without inhibiting cement hardening. The added metal compound also acts as a cement hardening accelerator.

Test Example> The effects of various metal compounds on the inhibition of cement hardening by wood extract components were tested.

Cement: A mixture of standard sand = 1 = 2 was mixed with various WJ liquids at a water/cement ratio of 0.65 to prepare various green mortars.
lx4 cm), temperature 20℃, temperature approx.
After curing for one day in a thermostatic bath No. 1, the samples were cured for a predetermined period of time in water at 20° C. to obtain various mortar specimens. The mixed solution was made of 18 sheets of lOxlOx1cm plywood with saturated Ca
Add various copper compounds, zinc compounds, lead compounds, and aluminum compounds to the wood extract obtained after 48 hours of immersion in the (Oll)2 solution for 0.1 g each for $0.3.

0.5z and 1. It was added in the proportion of 100 ml. For comparison, mortar specimens prepared by blending solutions to which these metal compounds were not added were also prepared.

Table 1 summarizes the results of measuring the compressive strength of these mortar specimens after curing and hardening for a predetermined period of time.

In addition, regarding the compressive strength in Table 1, × marks indicate that no increase in strength was observed compared to mortar prepared using a solution without the addition of metal compounds, and ○ marks indicate that a slight increase in strength was observed. The ◎ marks indicate those in which the strength increased significantly, and the numerical value shown in parentheses under the ◎ mark is the amount of metal compound added when the strength development reached the maximum.

From the results shown in Table 1, although the effect is not necessarily constant depending on the type of metal compound and the amount added, it is generally found that mixing wood with these metal compounds has an effect on cement hardening inhibition of wood extract components. It is known that it is possible to suppress

In particular, copper chloride and copper sulfide are used for copper compounds, zinc sulfate is used for zinc compounds, lead chloride and lead Ta oxide are used for lead-1 arsenide, and aluminum chloride and aluminum sulfate are used for aluminum-f arsenide. Among iron compounds, iron chloride was found to have a remarkable inhibitory effect.

Furthermore, when we investigated the fine structure of the mortar specimens in which these remarkable inhibitory effects were obtained using a scanning electron microscope, we found that in all cases, gel-like particles were adsorbed and polymerization occurred due to chemical bonding. fibrous or granular
A lumpy product was observed. This is Fe, which has greater stability than the ions Ca'', Ni', Na'', etc. released from cement into the liquid phase.

Metal ions such as Cu, Zn, Pb, and 8 were eluted from the added metal compound, and it was determined that these metal ions were complex salts produced by combining with wood extract components.

<Example> Drunkfish Melabi wood chips = 20$ Portland cement = 38z Water = 4oz Metal compounds: 2z According to the above formulation, each metal compound is dissolved in water to make an aqueous solution, and the aqueous solution is added to a mixture of wood chips and cement. After addition and mixing, the mixture was molded and cured using a conventional method to obtain a wood cement board. The metal compounds used were copper sulfate, copper nitrate, zinc chloride,
There are five types: aluminum sulfate, and ferric pig iron chloride. Under similar conditions, wood cement boards obtained by impregnating wood chips with the same amount of metal [aluminium sulfate], and wood cement obtained by increasing the water content without mixing metal compounds. The board was used for comparison.

After curing the wood cement board according to the present invention and the comparative material thus obtained, the bending strength was measured after one week, two weeks, and four weeks using a conventional method. The results are shown in Table 2.

Present invention Copper sulfate 78 88 100
Copper nitrate 75 83 95 Salt 1 Arsenic
70 82 93 Aluminum sulfate 61 6
8 75 Ferric chloride G7 74 85 Comparative material Aluminum sulfate (impregnated) 43 52 66'-
323850 From the results shown in Table 2, the bending strength of the comparative materials produced without the addition of metal compounds was not sufficient, whereas the materials according to the present invention all showed a so-called remarkable increase in strength. . This was determined to be because, in the case of the present invention, the inhibition of hardening of cement due to wood extract components was eliminated by the addition of the metal compound, and sufficient hardening was achieved. Moreover, even when compared with a comparative material obtained by impregnating a piece of wood with a metal compound, the wood cement board obtained by the method of the present invention had excellent bending strength at all ages. In particular, it was confirmed that the case according to the present invention exhibited excellent initial strength development, and the effect of promoting cement hardening by the added metal compound was obtained.

<Effects of the Invention> According to the present invention described above, cellulose in the main material such as wood chips and wood wool used for manufacturing wood cement boards,
Extracted components such as lignin, tannins, and sugars combine with metal compounds mixed in the mixing water at their interfaces to form highly stable insoluble complexes, so that the extracted components are absorbed into the water of the cement slurry. Elution is effectively prevented, cement hardening is not inhibited by the wood extract components, and therefore a wood cement board with excellent strength can be produced.

Furthermore, in the method of the present invention, since the metal compound is mixed into the mixing water, the cement hardening promoting effect of the metal compound can be utilized at the same time. Since the wood cement board manufactured by the present invention progresses in hardening at an early stage, handling during manufacturing is improved, such as being transported to the next process more quickly.

In addition, compared to the method of impregnating wood chips with a metal compound, the same effect on inhibiting cement hardening can be obtained with a smaller amount of metal compound, and the patent applicant Noda Plywood Co., Ltd. has the advantage of being highly economical. Agent Patent Attorney Fumi Higashihara Yoshibe Doma Takeda

Claims (2)

[Claims] (1) After kneading wood materials, cement, and water to form a mixed mat, the mixed mat is pressed and molded, and then cured and hardened to produce a wood cement board, which is stabilized by combining with wood extract components. A method for producing a wood cement board, characterized by mixing a metal compound that forms a high degree of complex into kneading water. (2) The metal compound is characterized in that it consists of one or more substances selected from sulfides, chlorides, and hydroxides of iron, copper, zinc, lead, and aluminum;
A method for manufacturing a wood cement board according to claim 1.