JPS6035217B2 - Manufacturing method for boiler heat insulation materials - Google Patents

Description

Detailed Description of the Invention The present invention uses a specific powdery resol-type phenolic resin as the main binder for dispersing, mixing, impregnating, fixing, or coating organic and inorganic substrates, and hexamethylene as a curing agent. The present invention relates to a method for producing heat insulating materials for crush injuries without using tetramine.

Generally, a powdered novolac type phenolic resin is used as a binder in the manufacturing method of heat insulating materials. This powdered novolac type phenolic resin contains 10% as a hardening agent.
The one to which ~15% by weight of hexamethylenetetramine (hereinafter abbreviated as hexamine) is added is currently considered to be the most useful binder for wound insulation materials. However, when using a binder for feeder heat insulation materials made of powdered novolac type phenolic resin and hexamine, the hexamine thermally decomposes when the molded heat insulation material is fired, generating ammonia and formaldehyde, which are harmful. As a gas, it deteriorates the working environment and has adverse effects on the human body, such as odor and rashes on workers, and is a problem in terms of industrial pollution, and there is a strong demand for improvement from the perspective of pollution control. Furthermore, in the wet method of dispersing, fixing, or coating powdered novolac type phenolic resin containing hexamine using a large amount of water, hexamine dissolves in water,
It flows out into the water system during dehydration molding, not only causing water pollution, but also reducing the effectiveness of the curing agent and delaying the curing reaction during heating and baking of the molded product, requiring a long time.
There are many drawbacks such as uneven firing of the product.
There is a strong desire to develop a resin that cures without the use of hexamine.

The purpose of the present invention is to prevent the above-mentioned drawbacks that occur in the conventional method of manufacturing feeder heat insulating materials using powdered novolac type phenolic resin with hexamine as a hardening agent as a binder. Provided is a method for producing heat insulating materials that use a resol-type phenol resin that hardens even without use, and that uses a specific resol-type phenol as a main binder, in which the resin has specific properties that will be described in detail later. There is something to do.

The present invention has a melting point of 50 to 9000, a nitrogen-containing group index of 0.1 to
1. F. A powder resol type phenol resin having a methylol group index of 0.2 to 1.0 is used as the main binder,
Without using hexamethylenetetramine as a curing agent,
Provided is a method of manufacturing a riser heat insulating material to be used.

The present invention has solved these various problems by using a specific powdered resol-type phenolic resin as the main binder in a method for manufacturing heat-insulating materials.

Resol type phenolic resin has different amounts of methylol groups, methylene groups, nitrogen-containing groups, etc. depending on the type of catalyst.
It is important to adjust the amount of these bonds depending on the purpose, and the particularly preferred specific resol type phenolic resin in the present invention contains nitrogen-containing groups and a large amount of highly reactive methylol groups in the molecule, so it is important to adjust the amount of bonding. The crosslinking density during thermosetting is also high, improving the strength of the molded product.

Furthermore, the methylol group contained in the resin acts effectively as a curing agent and crosslinking agent for novolak type resins, and when used in combination with novolak phenol resin, it is also effective as a crosslinking agent.

Furthermore, since the resol type phenolic resin is cured without the use of hexamine, the amount of gas generated during heat curing is reduced, and the working environment is significantly improved. Furthermore, since the resin does not contain hexamine, the hygroscopicity due to hexamine is low, the resin does not form lumps, and the storage stability in high temperature and high humidity periods is improved. Furthermore, since there is no elution or loss into the water system during suction molding, no water pollution occurs and it is effective in preventing pollution. Furthermore, since the nitrogen-containing group in the molecule is bonded to the highly hydrophilic OH group of the phenol nucleus, its affinity with water is reduced, no resin lumps are generated, and the temporary dispersibility of the slurry in the wet method is improved. , the stability is improved, and the effectiveness as a binder is further improved. The nitrogen-containing group index defined in the present invention indicates how many nitrogen-containing groups exist for one phenol nucleus in the phenol resin, and can be calculated as follows. be.

That is, in a 13C-FT-NMR analyzer, the intensity of the carbon peak of the nitrogen-containing group whose chemical shift appears at 46 to 51 ppm, and the intensity of the carbon peak bonded to the hydroxyl group of the phenol nucleus whose chemical shift appears at 143 to 15 $pm. It is a numerical value obtained by measuring the intensity and dividing the former integral value by the latter integral value. Furthermore, the methylol group index defined in the present invention indicates how many methylol groups exist for one phenol nucleus in the phenol resin, and can be calculated as follows. That is, 13C-F
Chemical shift is 60-65p in T-NMR analyzer
The intensity and chemical shift of the carbon peak of the methylol group that appears at pm is 143 to 15. The intensity of the carbon peak bonded to the hydroxyl group of the phenol nucleus that appears at pm is measured, and the value is calculated by dividing the integral value of the former by the integral value of the latter. . The characteristics of the specific powder resol type phenolic resin of the present invention are as follows. The melting point range is 50 to 90 qo, preferably 60 to 80 qo.

If the melting point is below 50 qo, resin lumps are likely to occur, and the melting point is 90 qo or less.
If the melt viscosity is higher than qo, the melt viscosity is high, so that the coating on the base material becomes insufficient and the strength decreases. The nitrogen-containing group index range is 0.1
-1.5, preferably 0.2-1.4. If the nitrogen-containing group index is less than 0.1, the hydrophilicity with water increases, resulting in poor dispersibility and stability, and if the nitrogen-containing group index is 1.5 or more, the amount of gas generated during firing increases, which is not preferable. The range of methylol group index is 0.2 to 1.0, preferably 0.3
~0.9.

If the methylol group index is less than 0.2, the curing speed will be slow.
Work efficiency decreases. Also, if it is 1.0 or more, it is too bad. This is not preferable because the ole group gradually undergoes a condensation reaction even at room temperature, resulting in poor storage stability. Examples of the present invention will be shown below.

Parts and percentages are by weight unless otherwise specified. Example 1 Pulp6. Mystery, 100 parts of water, 3 foundations of rock wool, 8
6. Powdered resol type phenolic resin having a melting point of 65q0, a nitrogen-containing group index of 0.3, and a methylol group index of 0.7 in 60 parts of silica sand. Add part of the kaji bran and mix it uniformly in a mixer to make a slurry.
become

Next, suction dehydration molding is carried out so that the moisture content becomes 40 to 42%.
Subsequently, it was heated and fired in a hot air circulation firing furnace at 160 to 180 qo for 3 hours to obtain a push moat heat insulating material with a specific gravity of 0.65 to 0.75. Example 2 6 parts of No. 8 silica sand, 1 part of aluminum powder, 14 parts of iron oxide, 6.0 parts of perlite, 6.0 parts of rock wool. Part 1 Powdered resol type phenolic resin with a melting point of 65 qo, a nitrogen-containing group index of 0.3, and a methylol group index of 0.76. Mix the anchor part uniformly with a blender mixer, then add 10 parts of water and mix uniformly for 3 minutes to form a slurry.

Subsequently, the material was suction molded to a moisture content of 40 to 42%, and then heated and fired in a hot air circulation firing furnace at 16 to 180 qo for 3 hours to obtain an exothermic heat insulating material with a specific gravity of 1.40. Example 3 Melting point 6500, nitrogen group index 0.5 methane.

Powdered resol type phenolic resin 75 with a sol group index of 0.5
A push moat insulation material was obtained according to Example 2 using a mixed binder consisting of 25 parts of powdered novolac type phenolic resin and 25 parts of powdered novolak type phenolic resin.
Example 4 Melting point 5yC, nitrogen-containing group index 0. F Methylol group index 0
．． A riser heat insulating material was obtained according to Example 1 using a mixed binder consisting of powdered resol type phenolic resin 5 and powdered novolac type phenolic resin 5.

Comparative Example 1 A riser heat insulating material was obtained according to Example 1 using a powdered novolac type phenol resin having a melting point of 70° C. and containing 10% hexamine.

Comparative Example 2 A feeder heat insulating material was obtained according to Example 1 using a powdered resol type phenolic resin having a melting point of 70° C., a nitrogen-containing group index of 0.0, and a methylol group index of 0.6.

Comparative Example 3 A press wound insulation material was obtained according to Example 2 using a powdered novolak type phenol resin having a melting point of 70 oo and containing 10% hexamine.

Test Example Table 1 shows the results of testing the performance of the heat insulators obtained in Examples 1 to 4 and Comparative Examples.

Table 1 Test Method Note 1 Slurry dispersibility was measured by taking 25 oo of water in a 10 ratio C in a beaker, gradually adding Resin 109 while stirring, stirring for 2 minutes, letting stand for 6 minutes, and stirring again.
Visually check the degree of dispersion.

Note 2 The slurry-resin lump generation temperature is
Collect a sample of resin, add 2500% water (5 ratio c), and while dispersing the resin, boil water is gradually added dropwise, and the temperature at which resin lumps are generated is measured.

Note 3 The concentration of ammonia gas generated is 5 parts of resin and 95 parts of silica sand.
Pour the homogeneous mixture into a mold (30 sides x 100 legs) heated to a mold temperature of 260°C, and after forming the sand plate in Step 6, immediately release the mold and seal the 340 x 150 x 25 side fence. The ammonia concentration in the generated gas is measured using a Kitagawa gas detection tube.

Note 4: Normal bending strength is based on JiS. Measured by K-6910 Powdered Phenolic Resin Test Method for Shell Mold.

Claims (1)

[Claims] 1. Melting point: 50 to 90°C, nitrogen-containing group index: 0.1 to 1.5,
A riser heat insulator characterized by using a powdered resol type phenolic resin having a characteristic of a methylol group index of 0.2 to 1.0 as the main binder, without adding hexamethylenetetramine as a hardening agent. manufacturing method. 2. The method for manufacturing feeder heat insulating materials according to claim 1, wherein the binder mainly consisting of a powdered resol type phenolic resin is mixed with a novolac type phenolic resin.