JPH08268763A - Refractory - Google Patents

Abstract

PURPOSE: To obtain refractories excellent in heat resistance and productivity and having improved durability. CONSTITUTION: A mixture consisting essentially of silicone modified phenolic resin obtd. by bringing organohydrogenpolysiloxane into an addition reaction to phenolic resin having unsatd. double bonds in the presence of a platinum catalyst, a crosslinking agent for the silicone modified phenolic resin and a refractory material is cured by heating to obtain the objective refractories.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refractory material, and more particularly to a refractory material having excellent heat resistance and durability using a silicone-modified phenolic resin which is industrially useful as a binder.

[0002]

2. Description of the Related Art A refractory material obtained by curing a refractory material using a thermosetting resin binder such as phenol resin is used for lining furnaces such as blast furnaces for iron making, car washing, converters, ladle, tundish, etc.
It is used as a casting nozzle, plate brick, etc.

However, such a refractory material has a drawback that its strength is remarkably lowered in the temperature range from about 500 ° C., which is the decomposition temperature of the binder, to 1300 ° C. at which it is made into ceramic. Therefore, as a method for improving the above-mentioned drawbacks, a method has been proposed in which a phenol resin in which a silane coupling agent is added and mixed in advance is mixed with a refractory material and cured (Japanese Patent Publication No. 61-37219).

However, in this case, it is difficult to uniformly disperse the silane coupling agent in the phenol resin, and since the silane coupling agent has a low boiling point, it evaporates to give off an odor and deteriorates the working environment. There was a drawback. Further, there is a drawback that the compression-molded product is easily broken and the workability is poor.

As a method for improving the strength at 500 ° C. to 1300 ° C., a mixture of a phenol resin and a silicone resin is added to and mixed with a refractory material to form a molded article, which is then heated at 1000 ° C. or less. For producing refractory (bricks) (JP-A-1-103952)
Alternatively, a method of producing a refractory by adding and mixing a condensation reaction product (silicone-modified phenolic resin) of a hydrolyzable functional group-containing silicone resin and a phenol resin to a refractory material and heating and curing it has been proposed ( JP-A-6-13576
No. 5).

However, the above-mentioned JP-A-1-10395
In the case of Japanese Patent Laid-Open No. 2-2, it is difficult to uniformly mix the phenol resin and the silicon resin to obtain a constant composition.
Not only is it inferior in workability, it is difficult to obtain a refractory of uniform quality, and since the bulk bulk density of the refractory is low, the strength at room temperature tends to be small, and the refractory molded product is easily broken. There was a flaw.

On the other hand, in the case of Japanese Unexamined Patent Publication No. 6-135765, there is no drawback that the composition becomes non-uniform as in the above case, but the alcohol removal reaction between the hydroxyl group of the phenol resin and the alkoxy group of the silicone resin. The Si-O-C type bond formed by hydrolysis hydrolyzes in the presence of an ionic component contained in the refractory material, particularly an alkaline component and water, and the silicone-modified phenolic resin causes cracking. It has the drawback of poor moisture resistance and poor durability. Further, the silicone-modified phenolic resin used in this method has a drawback that it is not preferable from an industrial point of view because it gels during the condensation reaction when the silicone content is increased.

[0008]

Therefore, as a result of intensive investigations by the present inventors to solve the above-mentioned drawbacks, a silicone-modified phenolic resin having no Si--O--C bond was used as a binder for the refractory material. In this case, it was found that the silicone-modified phenolic resin can be produced in an industrially stable state and there is no hydrolyzable bond, so that the moisture resistance becomes good and the durability is improved. Reached

Therefore, it is a first object of the present invention to provide a refractory material having excellent moisture resistance and heat resistance and improved durability. A second object of the present invention is to provide a refractory material suitable for industrial production.

[0010]

Means for Solving the Problems The above-mentioned objects of the present invention are obtained by at least (a) adding a reaction of a phenol resin having an unsaturated double bond with an organohydrogenpolysiloxane in the presence of a platinum catalyst. A silicone-modified phenolic resin, (b) a cross-linking agent for the silicone-modified phenolic resin, and (c) a refractory material, which is heat-cured to obtain a refractory material.

The component (a) used in the present invention acts as a binder for binding the refractory material described later, and its action is further promoted by combining it with a crosslinking agent. The above-mentioned component (a) is a silicone-modified phenol resin having no Si-O-C bond, which is synthesized by addition reaction of a phenol resin having an unsaturated double bond and an organohydrogenpolysiloxane described later. is there.

The above-mentioned phenol resin having an unsaturated double bond is, for example, a novolac type phenol resin obtained by reacting phenols and aldehydes in the presence of an acidic catalyst, and the same in the presence of an alkaline catalyst. Examples thereof include resins obtained by allyl etherifying the hydroxyl groups of the cresol type phenol resin obtained in the above, and allylated phenol resins obtained by reacting allylphenols with aldehydes. Among these phenol resins, it is particularly preferable to use one having an average of 1 to 3 alkenyl groups in one molecule of the phenol resin.

Specific examples of such a phenol resin include, for example, a novolak type phenol resin containing an allyl group at both ends or side chains, a partially allyl etherified novolak type or resol type phenol resin,
A resin obtained by partially reacting the phenolic hydroxyl group in the phenol resin with allyl glycidyl ether can be used. When an organohydrogenpolysiloxane having one Si-H group is used, phenol resin 1
The number of alkenyl groups in the molecule may exceed three.

In the present invention, examples of the organohydrogenpolysiloxane used for modifying the phenol resin include compounds represented by the general formula R _a H _b SiO _[ 4- _{(a + b)] / 2.} . R in the general formula is a substituted or unsubstituted monovalent hydrocarbon group, and a and b are 0 <a <
It is a number that satisfies 4, 0 <b <2 and 0 <a + b <4.

Specific examples of R in the above general formula include alkyl groups such as methyl group, ethyl group and propyl group, aryl groups such as phenyl group, tolyl group, phenethyl group and naphthyl group, trifluoropropyl group and CF. ₃ (CF ₂ ) ₃ CH
_{2 CH 2 -, CF 3 (} CF 2) 7 CH 2 CH 2 - halogenated alkyl group such as and the like. Among these groups, a methyl group or a phenyl group is preferable from the viewpoint of industrial use, and in particular, a methyl group having a phenyl group from the viewpoint of improving the heat resistance of the obtained refractory, the reactivity with the phenol resin, and the compatibility. Preference is given to using phenylorganohydrogenpolysiloxanes.

As such an organohydrogenpolysiloxane, S in one molecule is such that hydrosilylation with an alkenyl group-containing phenol resin does not cause gelation.
It is preferable to use one having an i-H bond. Specific examples of the above organohydrogenpolysiloxane include compounds represented by the following chemical formulas 1 to 7. In the chemical formula, Me is a methyl group, P
r represents an n-propyl group, Bu represents an n-butyl group, and Ph represents a phenyl group.

[0017]

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[0018]

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[0019]

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[0020]

[Chemical 4]

[0021]

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[0022]

[Chemical 6]

[0023]

[Chemical 7] Further, a copolymer composed of the following chemical formula 8 and a SiO ₂ unit, a copolymer composed of an HSiO _1.5 unit and a MeSiO _1.5 unit, and the like can be mentioned.

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The platinum catalyst used in the silicone-modified phenolic resin acts as a catalyst for the addition reaction of the phenolic resin having the unsaturated double bond with the organohydrogenpolysiloxane. As such a platinum catalyst, platinum is preferably tetravalent or zero-valent, and particularly, a phenolic hydroxyl group and Si
From the viewpoint of suppressing the dehydrogenation reaction of the —H group, it is preferable to use a zero-valent platinum catalyst.

Specific examples of such a platinum catalyst include chloroplatinic acid and platinum coordinated with various unsaturated compounds. The amount of platinum catalyst used is 1 to 1 with respect to the used organohydrogenpolysiloxane.
It is preferably 1,000 ppm, especially 5 to 50
It is preferably 0 ppm. The amount used can be appropriately adjusted according to the reaction time.

The addition reaction is generally carried out in an aromatic solvent such as xylene, toluene or ethylbenzene, a ketone solvent such as methyl ethyl ketone, methyl isobutyl ketone or cyclohexanone, or an ester solvent such as ethyl acetate, propyl acetate or isobutyl acetate. The temperature is higher than the melting point of the phenol resin (for example, 50 to 160 ° C.).

When the silicone-modified phenolic resin used in the present invention is produced, the ratio of the organohydrogenpolysiloxane to the phenolic resin is determined by the amount of alkenyl groups in the phenolic resin and the S--H group in the organohydrogenpolysiloxane. It can be appropriately determined by adjusting the amount. The use ratio is preferably high (the content of silicone is high) from the viewpoint of increasing the heat resistance of the refractory material, but is preferably low from the viewpoint of preventing the strength from decreasing when the refractory material is used.

Therefore, in the addition reaction, 10 to 300 parts by weight of organohydrogenpolysiloxane, especially 20 to 100 parts by weight of the organohydrogenpolysiloxane is added to 100 parts by weight of the phenol resin.
It is preferable to use 200 parts by weight. Usage is 300
If the amount is more than 10 parts by weight, the strength of the refractory is deteriorated and the manufacturing cost is high, which is uneconomical.

In the present invention, the solution obtained by reacting the phenolic resin with the organohydrogenpolysiloxane can be used as it is as the component (a) and can be used as a mixture with a refractory material described later. In this case, the refractory is manufactured by heating and molding while removing the solvent. However, in general,
The solvent is removed from the reaction solution containing the components by a known drying means such as vacuum concentration and spray drying before use. In the present invention, from the viewpoint of improving the strength of the refractory material, the component (a) is used together with the crosslinking agent which is the component (b).

The cross-linking agent which is the above-mentioned component (b) can be appropriately selected and used from known cross-linking agents for phenolic resins. Examples of such a cross-linking agent include hexamethylenetetramine and epoxy group-containing compounds such as various epoxy resins. Particularly, the epoxy group-containing compound is used because of its high reactivity and high cross-linking efficiency. Is preferred. The above epoxy group-containing compound is not particularly limited as long as it has two or more epoxy groups in one molecule.

Examples of such an epoxy group-containing compound are represented by polycondensation products of epichlorohydrin and bisphenol A, glycidyl ether compounds of novolac type or resol type phenol resins, diepoxy compounds of vinylcyclohexene oxide, and the following chemical formula 9. Examples thereof include compounds, copolymers of glycidyl (meth) acrylate with other polymerizable monomers, trimethylolpropane triglycidyl ether compounds, and trimethylolethane triglycidyl ether compounds.

[Chemical 9] When the above epoxy group-containing compound is used as the component (b), from the viewpoint of obtaining a refractory having high strength, use 5 to 100 parts by weight of the component (b) with respect to 100 parts by weight of the component (a). Is preferred.

The refractory material which is the component (c) used in the present invention is not particularly limited, and can be appropriately selected and used from the refractory materials known as refractory aggregates, refractory aggregates and the like. . Specific examples of such refractory materials include, for example, wax stone, burnt shale shale, synthetic mullite, alumina,
Magnesia, zircon, chromium, spinel, phosphorous graphite, silica stone, lime, silicon carbide, boron carbide, titanium carbide,
Aluminum nitride, boron nitride, silicon nitride, ZrB ₂ , T
Examples thereof include iB, carbon fiber, ceramic fiber and the like.

Further, in order to improve hot strength and corrosion resistance, the above refractory material may be used in combination with a metal powder or an alloy powder having a melting point of 1,000 ° C. or less.
The amount of the component (c) used is preferably 500 to 10,000 parts by weight with respect to 100 parts by weight of the component (a). If it exceeds 10,000 parts by weight, the force for bonding the refractory material is insufficient, and if it is less than 500 parts by weight, the strength of the refractory material decreases.

The refractory material of the present invention comprises:
It can be obtained by mixing component (b) and component (c), and then heating and curing. The heating temperature in this case may be a temperature required for the self-condensation of the silicone-modified phenolic resin as the component (a) or the crosslinking of the crosslinking agent as the component (b), and is usually 100 to 300 ° C. , Preferably 150 to 250 ° C. When the refractory has a specific shape, a mold or a mold may be filled with the above mixture and molded under pressure. Molding pressure in this case is usually 50~2,000kg / cm ^2, particularly preferably 100~10,000kg / cm ^2.

[0035]

INDUSTRIAL APPLICABILITY Since the refractory of the present invention uses a silicone-modified phenol resin having no Si--O--C bond as a binder of a refractory material, it has excellent moisture resistance and improved durability. , Less decrease in strength at 500 to 1300 ° C, and excellent in heat resistance. Further, since a silicone-modified phenolic resin that can be produced industrially stably is used as a binder, the productivity is better than that of conventional refractories.

[0036]

EXAMPLES The present invention will be described in more detail by way of examples, which should not be construed as limiting the invention. Moreover, all "parts" mean "parts by weight". Example 1. Synthesis of Silicone-Modified Phenolic Resin-A 200 parts of methyl isobutyl ketone in a four-necked flask, 120 parts of allylphenol novolac resin whose average composition formula is represented by the following chemical formula 10, and methylphenyl whose average composition formula is represented by the following chemical formula 11 80 parts of hydrogen polysiloxane and 0.3 part of platinum catalyst (CAT PL-50T: trade name of Shin-Etsu Chemical Co., Ltd.) were charged.

[Chemical 10]

[Chemical 11]

After carrying out the hydrosilylation reaction at 110 to 120 ° C. for 8 hours and confirming the disappearance of the residual SiH bond by infrared absorption spectrum, the product was concentrated under reduced pressure and the softening point was 75 ° C. and 150 ° C. A silicone-modified phenolol resin-A used in the present invention having a volatile content of 0.5% by weight when heated for 1 hour was obtained.

Refractory Preparation 8 parts synthetic mullite, 66 parts alumina, 14 magnesia
Part, silicone-modified phenolic resin-A9 synthesized previously
And 3 parts of an epoxy resin (Epicote 1004: trade name of Yuka Shell Epoxy Co., Ltd.) were mixed and uniformly dispersed using a hammer mill to obtain a mixed dispersion.

The obtained mixed dispersion was filled in a molding die, heat-cured at 200 ° C. for 4 hours under a pressure of 200 kg / cm ² , and after-baked at 180 ° C. for 4 hours to obtain the fire resistance of the present invention. I got a thing. Regarding the obtained refractory (referred to as refractory before humidification), the physical properties shown in Table 1 and 800
The results of measuring the bending strength at ° C are as shown in Table 1. In addition, these measurements were performed according to JIS.

Further, the prepared mixed dispersion (before being filled in a molding die) was stored in a thermo-hygrostat having a relative humidity of 80% at 50 ° C. for 2 weeks (referred to as refractory after humidification). . A refractory material was prepared using this mixed dispersion in the same manner as described above, and the physical properties and bending strength at 800 ° C. of the refractory material were measured, and the results are shown in Table 1.

[0041]

[Table 1]

Example 2. Synthesis of Silicone Modified Phenolic Resin-B Allylphenol novolac resin 1 used in Example 1
The same as Example 1 except that 140 parts of the partially allylated phenol novolac represented by the following chemical formula 12 was used instead of 20 parts and the phenylmethyl hydrogen polysiloxane was changed to 60 parts. And the softening point is 6
Volatile content is 0.3 when heated at 5 ℃ and 150 ℃ for 1 hour.
A weight percent of silicone modified phenolol resin-B used in the present invention was obtained.

[Chemical 12]

Preparation of refractory material : In the same manner as in Example 1 except that the silicone-modified phenolic resin-A previously synthesized was used in place of the silicone-modified phenolic resin-A, each mixture before and after storage was mixed. A refractory material was prepared using the dispersion, and the physical properties and bending strength at 800 ° C. of each refractory material were measured in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 1. In a four-necked flask equipped with a synthetic ester adapter of silicone-modified phenolic resin-C, 200 parts of methyl isobutyl ketone, the average composition formula is
140 parts of the novolac type phenol resin represented by the formula, 60 parts of methylmethoxydisiloxane represented by the following chemical formula 14 and 0.1 part of tetrabutyl titanate are charged, and a methanol removal reaction is performed at 100 to 110 ° C. for 3 hours. However, it was impossible to concentrate under reduced pressure, because gelation occurred when 23 ml of methanol was distilled out.

[Chemical 13]

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Therefore, when the reaction was carried out again under the same conditions and 14 ml of methanol was distilled off (100 ° C.
After 1.5 hours of reaction, the reaction was stopped and then concentrated under reduced pressure to distill off methyl isobutyl ketone and unreacted siloxane, and the softening point was 86 ° C and 150 ° C for 1 hour. 166 parts of silicone-modified phenolol resin-C having a volatile content of 1.2% by weight when heated was obtained.

Preparation of refractory material : Each mixture before and after storage was the same as in Example 1 except that the silicone-modified phenol resin-C synthesized above was used in place of the silicone-modified phenol resin-A. A refractory material was prepared using the dispersion, and the physical properties and bending strength at 800 ° C. of each refractory material were measured in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 2. Silicone-modified phenolic resin-D Novolak type phenolic resin was changed to 180 parts, and 60 parts of methyl methoxydisiloxane was replaced with 20 parts of methyltrimethoxysilane.
Silicone-modified phenolic resin-D19 having a softening point of 92 ° C and a volatile content of 0.6% by weight at 150 ° C for 1 hour.
I got 0 copies.

Preparation of refractory material : Each mixture before and after storage was the same as in Example 1 except that the silicone-modified phenol resin-A synthesized above was used in place of the silicone-modified phenol resin-A. A refractory material was prepared using the dispersion, and the physical properties and bending strength at 800 ° C. of each refractory material were measured in the same manner as in Example 1, and the results are shown in Table 1.

The results shown in Table 1 show that the refractory material of the present invention is excellent in heat resistance and, even when the refractory material is manufactured after the mixture is stored under high humidity, the refractory material having less strength reduction and excellent durability can be obtained. Is to demonstrate. In the case of synthesizing the silicone-modified phenolic resins A and B shown in Table 1, the silicone-modified phenolic resins C and D can be stably modified because gelation does not occur during the reaction. However, if the reaction time is prolonged, gelation tends to occur, so that stable silicone modification cannot be performed.

In particular, when the disiloxane represented by the chemical formula 14 is used, since the disiloxane is polyfunctional, gelation occurs even when the solvent is distilled off unless the reaction is stopped midway. Therefore, it becomes difficult to take out the product from the reaction vessel. Therefore, in this case, only silicone modification which does not cause gelation can be performed, and the heat resistance of the obtained resin is low.

Claims (3)

[Claims] 1. At least (a) a silicone-modified phenol resin obtained by addition reaction of an organohydrogenpolysiloxane with a phenol resin having an unsaturated double bond in the presence of a platinum catalyst, and (b) the silicone-modified phenol. A refractory material obtained by heating and curing a mixture of a resin cross-linking agent and (c) a refractory material. 2. The refractory material according to claim 1, wherein the organohydrogenpolysiloxane is methylphenylhydrogenpolysiloxane. 3. The refractory material according to claim 1, wherein the crosslinking agent for the silicone-modified phenolic resin is an epoxy group-containing compound.