JPS5946905B2 - Method of manufacturing architectural boards - Google Patents

Description

[Detailed description of the invention] This invention relates to a method of manufacturing a construction board.

Architectural boards made by bonding wood chips with a binder include chip boards, particle boards, wood chip cement boards, and the like.

Chipboard and particle board are made by bonding wood chips with an organic binder, and wood cement board is made by bonding wood chips with an inorganic binder.

However, each of these construction boards had the following problems.

That is, architectural boards using organic binders lack inflammability, and building boards using inorganic binders do not have such drawbacks, but are heavy and lack workability.

Therefore, an object of the present invention is to provide a method for manufacturing a construction board that is lightweight, easy to work with, and highly nonflammable.

The feature of this invention is that calcium aluminate monosulfate hydrate (3CaO-A1203 ・CaS
MSH is produced by preparing O4.12H20 (hereinafter abbreviated as MSH), wood chips, and gypsum, mixing these in the presence of water to create a mixture, shaping this, and curing it.
The purpose is to harden H and bond the wood chips.

That is, this invention hardens MSH with gypsum and water to form calcium aluminate trisulfate hydrate (3CaO・A1□03・3CaSO4・3
1 to 32H20 (hereinafter abbreviated as TSH), and this high strength TSH is used as a binder for wood chips.

The thus obtained architectural board has significantly greater strength than the architectural board using MSH1 gypsum and TSH alone as binders for wood chips, and is also lightweight and easy to work with.

Next, this invention will be explained in detail.

The wood chips used in this invention may be ordinary ones.

Furthermore, MSH and gypsum produced by conventional methods are used.

For example, MSH can be obtained by selecting a CaO component raw material, an Al2O3 component raw material, and a CaSO4 component raw material in a predetermined molar ratio, and subjecting them to wet heat synthesis.

The mixing ratio of MSH, wood chips, gypsum and water is preferably 10 to 40% by weight of wood chips (hereinafter abbreviated as %), preferably 20 to 30%.

If the amount of wood chips is less than this, the mechanical properties such as strength of the building board will be lowered, and if it is more than this, the non-combustibility will tend to be impaired.

The total amount of MSH and gypsum is preferably 45 to 70%, preferably 50 to 60%.

If the amount is less than this range, the nonflammability of the building board will be impaired, and if it is more than this range, the mechanical properties such as strength will tend to decrease.

Preferably, water is added in an amount of about 20-30%.

A conventional method is used to mix MSH, wood chips, gypsum, and water.

At this time, it is preferable to take measures to suppress TSH conversion from MSH to TSH during mixing and shaping.

This TSH formation suppression measure can be taken by adjusting the pH of the mixture and the like.

That is, the inventors found that the conversion of MSH to TSH is influenced by the temperature and the pH of the system.

For example, TSH formation is promoted at a temperature of 50 to 70°C, but suppressed at other temperatures.

Further, when the pH of the system is 11.0 to 11.5, the TSH conversion reaction is promoted and the reaction is completed in several minutes, but at other temperatures it becomes extremely slow.

Therefore, measures to suppress TSH formation can be taken by adjusting these factors.

Specifically, wood chips, MSH, and water are mixed and adjusted to pH
A method of mixing gypsum after adjusting the pH, a method of mixing pH-adjusted water and wood chips and adding a mixture of MSH and gypsum to this, and a method of mixing MSH, gypsum and pH-adjusted water in advance, A method such as adding and kneading wood chips to this is used.

Note that TSH suppression measures are not always required.

That is, as long as most of the MSH is not converted into TSH, there is no problem even if MSH is converted into TSH during mixing and shaping.

A conventional shaping method is used.

However, wood chips are bulky and lightweight, and it is known that if the wood chips are shaped while maintaining the chip shape, the mechanical strength of the construction board will increase.

Therefore, the inventors investigated two different methods and found that the most favorable results could be obtained by using a press method, especially a semi-dry press method that uses the minimum amount of water and prevents water from seeping out during pressing. I found it.

Most preferably, curing is carried out under pressure.

If molded with MSH suppressed from turning into TSH, if it is subjected to gentle pressure, the internal stress due to the bulkiness of the wood chips will increase, causing springback and deformation, so it is especially important to cure and harden it under pressure. is preferred.

In this case, curing is performed at a temperature of 40 to 70°C under pressure.
It is preferable to carry out the

After curing and curing, the architectural board is preferably dried to remove excess moisture.

This contributes to improving mechanical strength, but also to improving workability.

The construction board obtained in this way has a bulk specific gravity of almost 0.
．． 6 to 1.2, mechanical strength (musical strength) is about 50 to
250 kg/cril, and is highly nonflammable, heat insulating, water resistant, and easy to work with.

Next, examples will be described.

Example 1 Slaked lime: 3 moles, aluminum hydroxide 2 moles, gypsum 1
1 mol was placed in an autoclave, and water in an amount 1.5 times the weight of these raw materials was further added.

Next, the temperature was raised to 180°C while stirring,
After continuing the reaction at that temperature for about 2 hours, it was cooled to room temperature to obtain a slurry reaction product.

This reaction product was confirmed to be MSH by X-ray diffraction analysis.

In this case, the MSH was 44% solids and the pH of the slurry was 12.7.

Next, 1,200 parts by weight (hereinafter referred to as "parts") of this MSH slurry IJ-1 and 300 parts of gypsum were mixed and the pH was adjusted to 12.
．． Adjusted to 6.

Meanwhile, prepare 200 parts of wood chips, mix them with the above-mentioned mixed slurry, and form a mold (300 x 300 x 12 mm).
) and shaped at a pressure of 40 kg/crA.

This product did not ooze out moisture during shaping.

Next, the mold was placed under a press at a temperature of 50°C.
The material was cured for about 1 hour, then removed from the mold and dried at 50°C to obtain a construction board.

The bulk specific gravity of this architectural board was 0.87, and the bending strength was 1221 B'i.

Example 2 1,000 parts of MSH sluic IJ obtained in Example 1,
150 parts of wood chips were mixed uniformly.

On the other hand, 220 parts of gypsum was prepared and filled into the same mold as in Example 1 while being mixed with the above-mentioned mixture of wood chips and MSH slurry.

Next, this was press-shaped, hardened at a temperature of 60°C, and then dried by removing pressure.

The construction board thus obtained has a bulk specific gravity of 0.74.
The bending strength was 76 kg/i.

In addition, the dissolution rate after 7 days of immersion in running water was 0.17%, and the water absorption rate was 5.
It was 8%.

Example 3 The MSH slurry obtained in Example 1 was dried at 40°C and then ground to obtain MSH powder.

600 parts of this MSH powder and 300 parts of gypsum were mixed.

On the other hand, 200 parts of wood chips were adjusted to pH with Ca(OH7)2.
It was uniformly moistened with 700 parts of water adjusted to 12.5.

Thereafter, the MSH-gypsum mixed powder and wet wood chips were placed in a mold and mixed, followed by press shaping.

Then, it was heated as it was and press hardened at 40°C for about 1 hour.

Then, this product was taken out of the mold and dried at 50°C.

This construction board has a bulk specific gravity of 1.14 and a bending strength of 186.
It was kycnl.

Comparative Example In Examples 1 and 2.3, MSH was converted into TSH, then shaped and dried to obtain a construction board.

When this architectural board was immersed in water, it swelled and eventually fell apart.

Claims (1)

[Claims] 1 Calcium aluminate monosulfate hydrate, wood chips, and gypsum are prepared, and these are mixed in the presence of water to create a mixture, which is shaped and then cured to produce calcium aluminate. A method for manufacturing a construction board, characterized by curing monosulfate hydrate and bonding wood chips. 2. A method for manufacturing a building board according to claim 1, in which curing of the calcium aluminate monosulfate hydrate is suppressed until the time of shaping. 3. In the method for manufacturing architectural boards as set forth in claim 1, the manufacturing ability of architectural boards is also claimed in which shaping is performed by a semi-dry pressing method that prevents water from seeping out when pressurized. 4. A method for manufacturing a building board according to claim 2, wherein curing is performed under pressure.