JPS5812225B2 - Insulating refractory lining construction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for constructing an insulating refractory lining, and particularly to a method for constructing an insulating refractory lining by spraying or coating on the inner surfaces of various steel manufacturing containers to form an insulating refractory wall. It is something.

Conventionally, tundishes and the like have been lined with fireproof insulation boards to prevent the temperature of molten steel from dropping, and in bottom pouring molds, it is necessary to keep the upper part of the mold warm in order to improve the yield of cast steel. For this reason, a fireproof insulation board is attached to the inner surface of the upper part of the mold.

However, in order to attach these fireproof insulation boards, it is necessary to apply fireproof mortar, nail driving, rivet driving, etc., which has the drawback of requiring labor and time.

Furthermore, the lining made of these fireproof and heat insulating boards essentially has seams between the boards, which causes penetration by molten steel through the seams, resulting in problems with durability and heat retention.

In addition, since tundishes and molds each have different shapes, it is necessary to create fireproof insulation boards in various shapes in advance to match the construction object, or to adapt the fireproof insulation board to the shape of the workpiece during installation. It is necessary to perform cutting work at the same time, which has the disadvantage of complicating the construction work and manufacturing of the fireproof board.

Furthermore, since these fireproof insulation boards are flat, it is difficult to attach them to uneven or curved surfaces. It is extremely difficult to attach it.

Furthermore, although it is known to spray or apply alumina cement as a binder to refractory powder, inorganic fibers, and organic fibers, it has the disadvantage that it takes a long time to dry or heat up after application.

In view of the above-mentioned drawbacks of these insulating refractory lining methods, the present inventors conducted repeated research and experiments to obtain a heat insulating refractory lining method that does not have these drawbacks. This can be achieved by adding inorganic and/or organic fibers to the powder as required, and using a mixture of polyesters and/or polyethers, blowing agents and incyanates for spraying or coating. This led to the completion of the present invention.

Therefore, the present invention provides a combination of an inorganic refractory powder alone, an inorganic refractory powder and an inorganic fiber, an inorganic refractory powder and an organic fiber, or an inorganic refractory powder, an inorganic fiber, and an organic fiber. A heat-insulating refractory product characterized by spraying or applying a mixture of incyanates to a mixture of 5 to 40 parts by weight of polyesters or/and polyethers to the inner surface of a workpiece. This is the lining construction method.

The inorganic refractory powder used in the method of the present invention includes:
Examples include powders of refractory raw materials such as alumina, silica, chamotte, magnesia, and silicon carbide, and these are selected and used depending on the container to be treated, the area to be treated, etc.

Inorganic fibers used in the method of the present invention include inorganic fibers such as slag wool, asbestos, and kaolin.

The addition of inorganic fibers is effective in preventing cracks from occurring and parts of the wall from falling off during use of the fireproof and insulating wall, and the preferred amount used is 1 to 10 parts by weight.

Examples of the organic fibers used in the method of the present invention include fibrous materials obtained from pulp waste, wood pulp, linen waste, and synthetic fibers.

The addition of organic fibers is to reduce the weight of the fireproof insulation wall, increase the porosity and increase the room temperature susceptibility.

The polyesters and polyethers used in the method of the present invention include polyethers obtained by condensation polymerization of polyols and ethylene oxide or propylene oxide; polyesters obtained by condensation polymerization of dibasic acids and polyols. Polyethers made of trimethylolpropane, glycerin, hexanetriol, or nrubitol and ethylene oxide or propylene oxide; polyols containing three or more hydroxyl groups in the molecule, such as polyesters made of adipic acid or phthalic acid and glycerin. Polyethers made of polyethylene oxide or propylene oxide and polyesters made of a polyol containing three or more hydroxyl groups in the molecule and a dibasic acid are preferred because they form strong fireproof and heat insulating walls.

The amount of these polyesters and/or polyethers added is 5 to 40 parts by weight, and when the amount added is 5 parts by weight or less, the surfaces of aggregates, fibers, etc. are not wetted by them and uneven foaming is prevented. This is undesirable.

In addition, if the amount added is large and exceeds 40 parts by weight, when the formed heat-insulating fire-resistant wall comes into contact with molten steel, etc., a large amount of decomposed gas will be generated, causing problems such as cracks in the heat-insulating fire-resistant wall structure and deformation at high temperatures. Yes, it's not good.

Further, in order to maintain strength at high temperatures, it is preferable to use an inorganic powder binder such as powdered sodium silicate, borate, phosphate, etc. in combination.

A small amount of water, chlorofluoromethane, or methyl chloride is usually used as a blowing agent in the present invention, and these are added to the binder polyethers or polyesters in advance depending on the desired porosity of the heat insulating wall. Predetermined amount, e.g. 0.5
~5 parts by weight are dissolved and contained.

Examples of incyanates used as curing agents in the method of the present invention include toluylene diisocyanate and diphenylmethane diisocyanate.

In the method of the present invention, liquid polyester or polyether is added as a binder to the mixture of the above-mentioned refractory raw materials and fibers to form a potted clay.

By adding a curing agent such as incyanate to the potting clay, the potting clay immediately starts foaming at room temperature, and a hard porous heat insulating material is formed in a short period of time.

In other words, it is desirable to add the curing agent immediately before construction.

For example, in the case of spraying, the hardening agent is injected and mixed into the cup soil at the distal end of the spray gun's discharge port.

The sprayed cup soil adheres and begins to foam, forming a strong heat-insulating and fire-resistant wall.

The total porosity of the multi-insulator is preferably 40-75.

If it is less than 4%, the insulation and heat retention properties will decrease.

If it is 75 inches or more, the strength of the heat-insulating refractory is low, and the durability is poor when made into molten steel, etc., which is not preferable.

In the case of coating, the potting soil is applied by an extruder while a hardening agent is injected and mixed at the tip of the extruder.

With the construction method of the present invention, a heat-insulating fireproof wall of desired quality can be easily obtained at room temperature in a short time.

Furthermore, since the obtained heat-insulating fireproof wall does not contain moisture, a drying process is unnecessary and it can be used immediately.

Next, the present invention will be specifically explained with reference to Examples.3 Examples 1 95 parts by weight of No. 7 silica powder, 5 parts by weight of asbestos, and 3
3 parts by weight of powdered sodium silicate and 5 parts by weight of trichlorofluoromethane
30 parts by weight of glycerin-propylene oxide condensation polyether containing The mixture was discharged into a plate while mixing the two parts, and was applied to an iron plate to a thickness of about 20 mm.

The applied clay started foaming after about 90 seconds, and after about 3 minutes, it foamed to a thickness of about 50 mm and hardened.

The properties of the cured fireproof insulation material are as follows.

Adhesive strength with iron plate: 11.7Kg/cm2 Bending strength: 25.4Kq/cm2 Bulk specific gravity
0.51 Total porosity 70.8% Thermal conductivity (350°C) 0.12 Kcal/m. hr
℃Appearance Smooth surface with no cracks.

Example 2 100 parts by weight of Magne 7A fine powder with a particle size of 0.1 mm or less and 2 parts by weight of No. 1 powdered sodium silicate were kneaded with 22.5 parts by weight of adipic acid monoglycerin-ethylene glycol polyether containing 1 part by weight of water. Then, 16 parts by weight of a 30% by weight ethyl acetate solution of this cup soil and methylene diisocyanate was mixed externally at the tip of the spraying machine nozzle and sprayed onto the surface of the raw stone brick to a thickness of about 15 mm. .

The sprayed material started foaming after about 90 seconds, and after about 3 minutes it foamed to a thickness of about 25 ma and hardened.

The properties of the cured fireproof insulation material are as follows.

Adhesive strength with raw stone brick 14.3Kg/cm2 Bending strength 126.6Ky/cm2 Bulk specific gravity 0.99 Total porosity 54.0Chi Thermal conductivity
0.29Kcal/m. hr℃Appearance Smooth surface with no cracks.

Example 3 85 parts of alumina fine powder with a particle size of 0.1 mm or less, 15 parts of clay shamrock, 2 parts of hemp thread waste with a length of 8 m/m to 3 m/m,
Sorbitol-ethylene oxide condensation polyether 25 containing 1 part of water in a mixture of 1 part of sodium phosphate
This potted soil and 10 parts by weight of toluylene dinicyanate were internally kneaded at the tip of the extruder and discharged into a plate shape onto an iron plate of about 10 m. /m thick.

The applied clay started foaming after about 60 seconds, and after 2 minutes it foamed to a thickness of about 15 m/m and hardened.

The properties of the cured fireproof insulation material are shown below.

Adhesive strength to iron plate 15Kg/cm2 Bending strength 32Kg/cm2 Bulk specific gravity 0.7 Total porosity 65% Thermal conductivity (350℃) 0.21Kcal/box. H.
℃Appearance Smooth surface with no cracks.

Example 4 28 parts of sorbitol-propylene oxide condensed polyether containing 0.5% water was kneaded into a mixture consisting of 100 parts by weight of No. 7 silica sand, 2 parts by weight of slag wool, 2 parts of hemp thread waste, and 2 parts of powdered water glass. The mixture was filled into an extruder having a T-shaped die at the tip of the discharge section, and the potted clay and 7 parts by weight of toluylene dienedocyanate were coated on an iron plate to a thickness of about 15% while being internally kneaded at the tip of the extruder.

The applied clay started foaming after about 90 seconds, and foamed and hardened to a thickness of about 20 m/m after about 5 minutes.

The properties of the cured fireproof insulation material are shown below.

Adhesive strength to iron plate 15Kg/cm2 Bending strength 32Kg/cm2 Bulk specific gravity 0.7 Total porosity 55 Thermal conductivity (350℃) 0.28Kcal/m. h.
℃Appearance Smooth surface with no cracks.

Claims (1)

[Claims] 1 Inorganic refractory powder alone, both inorganic refractory powder and inorganic fiber, both inorganic refractory powder and organic fiber i, or three combinations of inorganic refractory powder, inorganic fiber, and organic fiber 10
Spray or apply a mixture of 0 parts by weight, 5 to 40 parts by weight of polyesters or/and polyethers, and an effective amount of foam-forming blowing agent to the inner surface of the workpiece. A method for lining a porous heat-insulating refractory material, characterized by: