JP2552959B2 - Fire resistant adhesive composition - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to carbon-containing refractory adhesives. The adhesive composition refers to a binder for molding the formed refractory material and the refractory material.

[0002]

2. Description of the Related Art Carbon-containing refractories currently used for refining metals are magnesia / graphite, alumina / graphite, alumina / silicon carbide / graphite and other refractory materials to which pitch or an organic binder such as phenol resin is added. After mixing or kneading and pressure molding, it is obtained by heat treatment at 200 to 300 ° C. The unfired refractory thus obtained is fired in a reducing atmosphere of about 1000 to 1500 ° C. when used directly after being built in a molten metal container (for example, unfired magnesia / graphite brick of a converter). It may be used later (for example, alumina / graphite nozzle for continuous casting).

Among the firing type refractory materials, the continuous casting nozzle 1 made of an alumina / graphite material is mainly subject to melting damage 1a in a portion in contact with molten steel as shown in FIGS. 1 and 2.
The used nozzles are either discarded or recovered and reused according to the remaining wall thickness.

Among the nozzles 1 recovered after use, those having a large remaining wall thickness are reused as they are.
As introduced in Japanese Patent No. 3347, there is a method of cutting the melt-dissipated portion and adhering the joining nozzle 7 with a refractory adhesive 6.

[0005]

When the adhesive 6 is examined in order to put such an adhesive processing into practical use, in the case of the fire-resistant adhesive composition which has been conventionally used, as shown in FIG. In the temperature range of 400 to 800 ° C., there is a tendency that the adhesive strength is remarkably lowered. In a region of higher temperature, the refractory adhesive composition is oxidized in a heating atmosphere to lower the adhesion temperature.

These problems are caused by the fact that the current refractory adhesive composition contains a phenol resin as a main component, so that the carbon component inside the resin dissociates the carbon bond inside the resin in the temperature range of interest, CO, CO It is due to the fact that it becomes ₂ , CH _4, etc. and disappears by oxidation. The temperature range in which such a decrease in bonding force occurs corresponds to the temperature range of preheating before use of the refractory for casting used, casting work, etc., and therefore, in the conventional refractory adhesive composition, this decrease in bonding force is caused. Was an important issue.

[0007]

The adhesive for carbon-containing refractories according to the present invention has a high temperature property, particularly an oxidation resistance of 400 to 400.
It is required to have excellent hot strength at 800 ° C and corrosion resistance. As a method for solving this problem, a refractory material, a thermosetting phenolic resin powder containing a resol type thermosetting phenolic resin alcohol solution and a benzylic type phenolic resin is added, and a metal powder is allowed to coexist as necessary. A fire-resistant adhesive composition was invented.
This refractory adhesive can develop the required adhesive strength by heat treatment at a temperature of 120 to 200 ° C., and can eliminate the problematic decrease in hot strength of 400 to 800 ° C.

[0008]

[Function] Resol-type phenol resin is thermosetting
Generally, curing starts at a temperature of about 70 ° C., whereas a benzylic ether type phenol resin does not heat cure at 130 ° C. or less. The refractory raw material and the benzylic ether type phenol resin are characterized in that they form a chelate bond and are crosslinked, and when the benzylic ether bond is decomposed, they form a methylene bridge while generating formalin, which is characterized by a long curing time.

Therefore, the refractory adhesive composition 6 of the present invention has a curing initiation temperature on the high temperature side as compared with the conventional ones.
Also, due to the characteristics such as long curing time, 40
In the temperature range of 0 to 800 ° C., the amount of undecomposed carbon bonds is kept high, the occurrence of residual stress as seen in the rapid hardening process is prevented, and high strength characteristics can be obtained.
FIG. 3 is a cross-sectional view showing a usage state after nozzle bonding.

At this time, if metals such as aluminum-magnesium alloy powder and aluminum powder are allowed to coexist,
Aluminum carbide, alumina spinel, and the like are generated by heating during casting, and a protective layer is formed inside the structure, so that oxidation of the refractory adhesive composition and the refractory raw material can be prevented and high strength can be exhibited.

When the refractory adhesive composition 6 is used for adhesion, the viscosity of the composition has a great influence on workability as described above. Conventional fire-resistant adhesive compositions may use water or glycol as a solvent for the phenol resin, but these have a surface tension of about 70 dyn / cm and have poor wettability with the fire-resistant raw material. In the case where the above is melted to form a refractory adhesive composition, the viscosity is high and workability may be impaired.

Further, in order to add the thermosetting phenol resin powder to solve the strength problem, the solubility of the resin is poor when the solvent is water or glycol. From this, the surface tension is 2
A low-viscosity (200 CPS or less) resol-type phenol resin solution using alcohols such as methyl alcohol, isopropyl alcohol, and ethyl alcohol, which have a low solubility of 0 dyn / cm and excellent solubility of thermosetting phenol resin powder, as a solvent. By using it, it becomes possible to solve these various problems.

[0013]

[Examples] Table 1 shows examples, in which a resol type thermosetting phenolic resin alcohol solution, a benzylic ether type phenolic resin-containing thermosetting phenolic resin powder, an antioxidant Al-Mg alloy powder, and a refractory powder (Al ₂ For each of the (O ₃ powder), the results of measuring the bonding workability and bonding bending strength when the compounding amount is changed are shown. (Adhesion workability relates to kneadability of the adhesive composition and application workability to the adhesion surface of the nozzle, and adhesive bending strength is evaluated by three-point bending strength as shown in FIG. 6.) In FIG. A composition, 8 is a pressurizer, 9 is a fulcrum, and 10 is an electric furnace.

[0014]

[Table 1A] Note 1) ◎: Good workability △: Lower limit of workable range ×: Not workable

[0015]

[Table 1B]

[0016]

[Table 1C]

[0017]

[Table 1D]

[0018]

[Table 1E]

[0019]

[Table 1F]

In Example 1, 5 parts of a resole-type thermosetting phenol resin methyl alcohol solution (resin content 60% by weight) was added.
The results are obtained by changing the amount in the range of ˜30 wt%, but from the viewpoint of workability, the range of 10 to 25 wt% is the usable range, and 20 wt% is the optimum ratio.

In Example 2, the thermosetting phenolic resin powder containing the benzylic ether type phenolic resin was changed to 0 to 10% by weight, but the range of 1 to 5% by weight is the usable range. , 3 considering strength
Weight percent is optimal.

In Example 3, a resol type thermosetting phenolic resin alcohol solution 2 selected from Examples 1 and 2 was used.
This is the case where 0% by weight and 3% by weight of the benzylic ether type phenol resin-containing thermosetting phenolic resin powder were used, and the amount of the antioxidant Al-Mg alloy powder was changed to 0 to 7% by weight. Workability is almost good, but 80
1-5 in the adhesive strength in the high temperature range exceeding 0 ° C
Weight% is the usable range, and 3 weight% is optimum.

The fire-resistant adhesive composition 6 thus selected this time is suitable for adhering carbon-containing refractories such as magnesia-graphite and alumina-graphite. Therefore, in order to use it as an adhesive between alumina and graphite bricks such as the immersion nozzle 1 for continuous casting, 10 to 25% by weight of a resol type thermosetting phenolic resin alcohol solution and a benzylic ether type phenolic resin-containing thermosetting resin are used. Phenolic Resin Powder 1 ~
7% by weight and 1 to 5% by weight of metal powder and the rest are mixed with a refractory raw material such as alumina and kneaded to produce a refractory adhesive composition 6.

The carbon-containing refractory used for bonding is prepared by removing the deposit such as metal and then applying the fire-resistant adhesive composition 6 kneaded on the bonding surface thinly and uniformly and bonding them together.
The adhesive strength depends on the joint thickness of the adhesive portion as shown in FIG. As is clear here, since the thinner the joint joint thickness is, the higher the adhesive strength is, the viscosity of the adhesive composition 6 is important, and the low viscosity one is excellent in the adhesiveness of the adhesive surface and the coating workability.

Curing of the refractory adhesive composition 6 after the coating operation is carried out in order to avoid generation of residual stress due to rapid curing.
Can cure benzylic ether type phenolic resin 1
Drying at a temperature of about 30 ° C. for 2 to 3 hours and further at a temperature of about 200 ° C. for 2 to 3 hours to develop the curing strength.
Two stages of drying are performed.

FIG. 5 compares the adhesive force of the carbon-containing nozzle 1 adhered according to Example 3-3 of Table 1 with that of the conventional adhering nozzle. As is apparent from the figure, both the strength at 400 to 800 ° C. and the strength in the high temperature region exceeding 1000 ° C., which are problematic, are significantly improved to two times or more as compared with the conventional adhesive composition. As described above, the fire-resistant adhesive composition 6 according to the present invention has excellent properties as compared with the conventional adhesive compositions.

[0027]

As described above, the fire resistant adhesive composition 6 according to the present invention is excellent in strength and workability and has a remarkable effect of improving durability as compared with the conventional adhesive compositions. is there. Further, since the fire-resistant adhesive composition 6 according to the present invention contains a phenolic resin as a main component, the immersion nozzle 1
It is not limited to the use only for adhesion of carbonaceous materials such as magnesia / graphite, alumina / graphite, alumina / silicon carbide / graphite, etc. It becomes wide.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a usage state of a continuous casting nozzle,

FIG. 2 is a cross-sectional view showing a nozzle usage state and a damage state,

FIG. 3 is a cross-sectional view showing a usage state after nozzle bonding,

FIG. 4 is a graph showing the relationship between joint thickness of an adhesive part and bending strength.

FIG. 5: Alumina / graphite matrix strength of nozzle, conventional adhesive composition and fire resistant adhesive composition of the present invention (20% by weight of resol type thermosetting phenolic resin alcohol solution, benzylic ether type thermosetting phenol) It is a graph which contrasted the hot bending strength at the time of using 3 weight% of resin powder and 3 weight% of Al-Mg alloy powder.

FIG. 6 shows a hot bending strength test apparatus.

[Explanation of symbols]

 1: Nozzle 2: Ladle 3: Tundish 4: Mold 5: Molten Steel 6: Adhesive Composition 7: Nozzle for Bonding 8: Pressing Rod 9: Support Point 10: Electric Furnace 1a: Melting Part 1b: Immersion Part

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hiroshi Sakamoto 12 Nakamachi, Muroran City, Hokkaido Inside Nippon Steel Co., Ltd. Muroran Works (72) Inventor Hiroshi Nakamura 8-2 Marushima Town, Amagasaki City, Hyogo Pref. In-house (72) Inventor Toyohiko Fujii 8-2 Marushima-cho, Amagasaki-shi, Hyogo Kanae Chemical Co., Ltd.

Claims (2)

(57) [Claims] 1. A thermosetting phenolic resin powder containing a benzylic ether type phenolic resin in an amount of 10 to 25% by weight of a resol type thermosetting phenolic resin alcohol solution and a refractory material are mixed to obtain 100% by weight. A fire-resistant adhesive composition characterized by 2. A refractory adhesive composition comprising the refractory adhesive composition according to claim 1 and a combination of one or more selected from the group consisting of aluminum-magnesium alloy powder and metallic aluminum powder. .