JPH0757682B2 - Method for producing self-hardening rice husk charcoal granules - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

TECHNICAL FIELD The present invention relates to a method for producing self-hardening rice husk charcoal granules using rice husk as a raw material.

[Prior art]

Rice husks obtained by threshing rice produce over 3.5 million tons of rice each year in Japan, where rice is the staple food. Most of this rice husk is discarded or incinerated except for being used for compost and the like. Further, as disclosed in JP-A-63-118203, it has been partially studied to manufacture boards by using rice husk as a raw material and solidifying it with an adhesive.

[Problems to be Solved by the Invention]

As described above, it cannot be said at all that rice husks are effectively used at present, and it cannot be said that the characteristics of rice husks are fully utilized by using them as raw materials for compost and boards. The present invention has been made in view of the above point, and makes it possible to effectively utilize the characteristics of the rice husk, and to make the rice husk useful for various applications such as a conductive material and a fireproof material. The purpose is.

[Means for Solving the Problems]

The present invention, the raw material of the rice husk charcoal, which is obtained by carbonizing the rice husks together with the synthetic raw material of the thermosetting resin, is introduced into the reaction vessel, and the reaction of synthesizing the thermosetting resin is carried out. The present invention relates to a method for producing a self-hardening rice husk charcoal granule, which comprises attaching a self-hardening thermosetting resin to the surface of the. The present invention will be described in detail below. Rice husk is obtained by threshing rice,
It contains a large amount of crude fiber, lignin, and siliceous matter, and the rice husk contains 16 to 18% by weight of silica. The type of rice is not particularly limited, and any rice husk of the type used for food can be used. The rice husks are preferably fired by drying and crushing the rice husks, and the crushed grain diameter of the rice husks is generally in the range of 140 μm to 1130 μm. The firing of rice husks is performed in a reducing atmosphere such as a nitrogen atmosphere in which oxygen is blocked, and the firing temperature is not particularly limited, but the lower limit of the firing temperature is about 400 ° C. If so, the rice husk cannot be carbonized sufficiently. Rice husks form charcoal at a calcination temperature of 400 ° C or higher, and at a calcination temperature of 600 ° C or lower, the rice husk charcoal is acidic and has a slightly high electric resistance, but when the calcination temperature is 700 ° C or higher, the rice husk coal has an electric resistance. It becomes small and shows good conductivity.
When the rice husk is carbonized so that the conductivity becomes higher, that is, the electric resistance becomes smaller, the fire resistance also becomes higher, and particularly when the electric resistance becomes smaller than the order of 10 ² Ωcm, the fire performance of the rice husk charcoal rapidly improves. To do. Therefore, it is desirable that the firing temperature is high, but the firing temperature that can obtain high conductivity performance and fire resistance performance while considering the yield of charcoal production is in the range of 1000 to 1200 ° C. Firing temperature is 1000
Above ℃, the electric resistance is 10 ² Ωc, which is equivalent to that of flake graphite.
If it is on the order of m and the firing temperature is 1200 ° C. or higher, the conductivity and the like can be further enhanced, but the yield of charcoal is rapidly reduced to 50% or less. By coating the surface of the rice husk charcoal granules obtained as described above with a self-hardening thermosetting resin, the self-hardening rice husk charcoal granules according to the present invention can be prepared. As the curable resin, novolac type phenol resin, resol type phenol resin, furan resin, melamine resin or the like can be used. Of these, phenolic resin is the most promising. And a self-hardening thermosetting resin means a low molecular weight resin that has not yet been cured, and is a thermosetting resin that once melts by heating or the like and then hardens and gels. Is something
A typical example thereof is an initial condensate of phenol resin. When making a self-hardening rice husk charcoal granules by coating the surface of the rice husk charcoal granules with a self-hardening thermosetting resin, the thermosetting resin was applied at the same time as the initial condensation product of the thermosetting resin was synthesized. It can be carried out by attaching it to the surface of the rice husk charcoal granules. That is, for example, when reacting the initial condensate of the phenol resin, by charging the rice husk charcoal granules together with phenols and aldehydes into the reaction vessel, by performing the synthetic reaction of the phenol resin in this state,
The self-hardening rice husk charcoal granules can be obtained by uniformly adhering the initial condensate of the phenolic resin on the surface of the rice husk charcoal granules, filtering this and drying. Since the rice husk charcoal granules have poor wettability with the resin, it is not possible to evenly adhere the thermosetting resin to the surface of the rice husk charcoal granules by kneading the rice husk charcoal granules and the thermosetting resin. It is difficult, but when synthesizing the initial condensation product of thermosetting resin, the rice husk charcoal granules are put in advance. In this method, the thermosetting resin is uniformly attached to the surface of the rice husk charcoal granules. Therefore, it is preferable to prepare the self-hardening rice husk charcoal granules by this method. Here, in the self-hardening rice husk carbon granules, the ratio of the rice husk carbon powder granules to the thermosetting resin is not particularly limited. It is generally set in the range of about 80 parts by weight. If the proportion of the thermosetting resin is less than 5 parts by weight, the mechanical properties of the layer for fireproofing or copper electroforming formed by molding the self-hardening rice husk charcoal powder may be insufficient, and If it exceeds 80 parts by weight, the proportion of the self-hardening rice husk granules in the layer for forming fire resistance and conductivity formed by molding the self-hardening rice husk charcoal granules will be small and the fire resistance and conductive performance will be insufficient. May be. The self-hardening rice husk charcoal granules of the present invention obtained as described above are formed by heating and pressing to form a layer by combining the rice husk charcoal granules using the self-hardening thermosetting resin as a binder. Can be used. For example, it can be formed into a thin plate shape and used as a fire-resistant or conductive plate material, and such a thin plate-shaped material can be used by sticking it on the surface of a wooden board as a fire-resistant layer or conductive layer. You can also do it. Further, as a method for forming a fire resistant or conductive layer on the surface of a substrate such as a wooden board, there are various methods other than forming and sticking the self-hardening rice husk powder and granules in this way.
First, the first method is a method in which self-hardening rice husk charcoal granules are sprayed on the surface of the substrate in a uniform thickness, and then heated and pressed to be laminated integrally on the surface of the substrate. The second method is to spread the self-hardening rice husk charcoal particles evenly.
An incompletely cured sheet material is created by pressurizing with a roll heated to about 50 to 100 ° C, and this sheet material is overlaid on the surface of the substrate and heat-pressed to be integrated with the surface of the substrate. It is a method of laminating. The third method is a method of laminating when a particle board or the like is manufactured as a substrate, and the self-hardening rice husk charcoal granules are uniformly arranged on the surface of a forming mat in which wood chips and an adhesive resin are kneaded. Then, it is a method of integrally laminating on the surface at the same time as plate making such as particle board by heat-press molding. Here, as described above, generally, the rice husk charcoal granules have poor wettability with the thermosetting resin, and if a mixture of the rice husk charcoal granules and the thermosetting resin is simply molded, the thermosetting resin becomes a binder. The resin and rice husk charcoal granules do not disperse uniformly, and variations in fire resistance and conductivity are likely to occur, but by coating the surface of the rice husk charcoal granules with a thermosetting resin as described above. The rice husk charcoal granules can be uniformly dispersed, and stable fire resistance performance and conductive performance can be obtained. The layer obtained by molding the rice husk charcoal granules as described above can be used as a refractory material because it can block the flame by the contained rice husk charcoal, and the rice husk charcoal has conductivity. Therefore, it can be used as a conductive material and can be used as a building material or the like that requires fire resistance and conductivity, and also has a sound insulating property due to its high surface density.

【Example】

Next, the present invention will be described in detail by way of examples. Example 1 Prepared by drying and grinding rice hulls 16
Take 1 kg of ~ 50 mesh rice husk powder (containing 17-18% by weight of silica), and use this in a reducing atmosphere at room temperature to 1000
Temperature up to 4 ° C / min and hold at 1000 ° C for 3 hours, then from 1000 ° C to 500 ° C at 4 ° C / min cooling rate, then from 500 ° C to room temperature 5 ° C
Firing was performed under the condition that the temperature was lowered at a temperature lowering rate of / min. The yield of the obtained rice husk charcoal granules was 520 g. Next, 94 parts by weight of phenol, 122 parts by weight of 37% formalin, 15 parts by weight of hexamethylenetetramine, and 307 parts by weight of the rice husk charcoal granules obtained as described above were charged into a reaction vessel. It takes about 60 minutes to raise the temperature to 90 ° C., react for 3 hours as it is, and after cooling, filtering and air drying, the surface of the rice husk charcoal granules has an initial condensation product of phenol resin. A self-hardening rice husk charcoal granular material coated with was obtained. The self-hardening rice husk charcoal granules had an average particle diameter of 450 μm and a phenol resin content of 30% by weight. Example 2 1 kg of the same rice husk powder and granules as in Example 1 was sampled, heated in a reducing atmosphere from room temperature to 800 ° C. at a temperature rising rate of 4 ° C./min, and kept at 800 ° C. for 3 hours, After this, the temperature is lowered from 800 ° C to 500 ° C at a cooling rate of 4 ° C / min.
Firing was performed under the condition that the temperature was decreased from 5 ° C to room temperature at a temperature decrease rate of 5 ° C / min. The yield of the obtained rice husk charcoal granules was 610 g. Using this rice husk charcoal powder, the rest of the procedure was carried out in the same manner as in Example 1 to obtain a self-hardening rice husk charcoal powder. The average particle size and phenol resin content of this self-hardening rice husk charcoal powder were almost the same as in Example 1. Example 3 1 kg of the same rice husk powder and granules as in Example 1 was collected, heated in a reducing atmosphere from room temperature to 600 ° C. at a heating rate of 4 ° C./min, and held at 600 ° C. for 3 hours, After this, the temperature is lowered from 600 ° C to 500 ° C at a cooling rate of 4 ° C / min, and further 500
Firing was performed under the condition that the temperature was decreased from 5 ° C to room temperature at a temperature decrease rate of 5 ° C / min. The yield of the obtained rice husk charcoal granules was 730 g. Using this rice husk charcoal powder, the rest of the procedure was carried out in the same manner as in Example 1 to obtain a self-hardening rice husk charcoal powder. The average particle size and phenol resin content of this self-hardening rice husk charcoal powder were almost the same as in Example 1. Comparative Example 1 Instead of the rice husk charcoal granules, scaly graphite having a fixed carbon content of 99.5% and an average particle diameter of 60 μm was used, and the self-hardening graphite granules were obtained in the same manner as in Example 1. This self-hardening graphite powder has an average particle size of 300 μm and a phenol resin content of 3
It was 1% by weight. Comparative Example 2 Self-hardening sawdust charcoal powder particles were used in the same manner as in Example 1 except that 28 mesh passing powder granules obtained by crushing sawdust charcoal (manufactured by Nippon Hayashi Co., Ltd.) were used instead of the rice husk charcoal powder granules. Got the body This self-hardening sawdust charcoal powder has an average particle size of 650 μm,
The content of phenolic resin was 28% by weight. Comparative Example 3 35 obtained by crushing cedar bark charcoal (manufactured by Nippon Hayashi Co., Ltd.)
A self-hardening bark charcoal granule was obtained in the same manner as in Example 1 except that the 0 μm-passing granule was used instead of the rice husk charcoal granule.
This self-curing bark charcoal powder had an average particle diameter of 480 μm and a phenol resin content of 31% by weight. Using the self-hardening powder obtained in the above Examples 1 to 3 and Comparative Examples 1 to 3, by heat-pressing for 10 minutes at 160 ° C. and 25 kg / cm ² , the density is 0.8 g. / cm ³ , 1.0g / c
A test plate having a thickness of 5 mm set to m ³ , 1.2 g / cm ³ and 1.4 g / cm ³ was prepared. The surface resistance and volume resistivity of this test plate were measured according to JIS K 6911. The results are shown in Table 1 for surface resistance and Table 2 for volume resistivity. As can be seen in Tables 1 and 2, the surface resistance and volume of the examples using rice husk charcoal were higher than those of Comparative Example 2 using sawdust charcoal and Comparative Example 3 using bark charcoal. It is confirmed that the resistivity is remarkably small and that it has excellent conductivity. In particular, the case of Example 1 in which rice husks were fired at 1000 ° C. was almost at the same level as that of Comparative Example 1 using flake graphite,
It is confirmed that the conductive performance is equivalent to that when using flake graphite. Next, using the test plates of Examples 1 to 3 and Comparative Examples 1 to 3 created as described above, a flame penetration test was performed to measure the fire resistance performance. In the flame penetration test, the flame temperature (contact temperature of the test plate surface) is 1150 to 1300 ° C, and the flame length is
150 mm, supply air-gas mixture pressure is 2 kg at the burner tip
Make a flame with a hand burner by adjusting so that it becomes / cm ² , and apply this flame vertically to the plane of the above 120 mm × 150 mm × 5 mm test plate to burn through the test plate and penetrate the flame. This was done by measuring the time. For comparison, the thickness is 5 mm and the density is 0.8 g / cm ³ , 1.0
A flame penetration test was similarly performed using particle boards of g / cm ³ , 1.2 / cm ³ , and 1.4 g / cm ³ . The results are shown in Table 3. As can be seen from Table 3, in each of the examples using the rice husk charcoal, Comparative Example 2 using sawdust charcoal, Comparative Example 3 using bark charcoal, and Comparative Example 4 of particle board were used. The time required for flame penetration is significantly longer than that of the other products, and it is confirmed to have excellent fire resistance performance. Especially rice husks 10
Example 1 fired at 00 ° C. has almost the same level as that of Comparative Example 1 using flake graphite, and it is confirmed that the fire resistance performance is equivalent to that of using flake graphite.

【The invention's effect】

As described above, in the present invention, since the self-hardening thermosetting resin is used by adhering to the surface of the granular material of the rice husk charcoal obtained by carbonizing the rice husk, the rice husk uses the thermosetting resin as a binder. It is possible to form a layer that combines coal powder and granules, and it is possible to effectively use the rice husk for members that need fire resistance and conductivity by utilizing the excellent fire resistance and conductivity performance of rice husk charcoal. It is a thing. In addition, the rice husk charcoal powder and granules are put into the reaction vessel together with the thermosetting resin synthesis raw material, and the synthetic reaction of the thermosetting resin is carried out, so that the surface of the rice husk charcoal powder is self-hardened by thermosetting. Since the adhesive resin is attached, it is possible to evenly disperse the thermosetting resin and the rice husk charcoal granules that have poor wettability with each other simply by mixing the rice husk charcoal granules with the thermosetting resin. However, by coating the surface of the rice husk charcoal granules while synthesizing the thermosetting resin in the reaction vessel, self-curing rice husks in which the thermosetting resin is evenly attached to the surface of the rice husk granules It is possible to manufacture carbon powder granules, and when molding using self-curing rice husk carbon powder granules, a layer in which rice husk carbon powder granules are uniformly dispersed in a thermosetting resin is formed. It is possible to reduce the fire resistance and conductive performance of rice husk charcoal granules. It is those that can be exhibited in.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Atsushi Takamatsu 2-14-5 Uchidai-cho, Miyakojima-ku, Osaka City, Osaka Prefecture (56) References JP-A-59-102870 (JP, A) JP-A-64-14108 (JP, A) JP 63-118203 (JP, A)

Claims (2)

[Claims] 1. A granular material of rice husk charcoal is prepared by charging a raw material for synthesizing a thermosetting resin into a reaction vessel and a granular material of rice husk charcoal obtained by carbonizing rice husk to cause a synthetic reaction of the thermosetting resin. A method for producing self-hardening rice husk charcoal granules, characterized in that a self-hardening thermosetting resin is adhered to the surface of. 2. The method for producing a self-hardening rice husk charcoal granule according to claim 1, wherein the self-hardening thermosetting resin is an initial condensation product of a phenol resin.