JP2003292556A - Binder for fireproof material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a binder for a fireproof material, containing a resol type phenolic resin as an indispensable component, capable of prohibiting working environment pollution and reduction in a substantial amount of the binder caused by the evaporation of monomer components. <P>SOLUTION: This binder for the fireproof material is characterized by containing the resol phenolic resin obtained by the reaction of an aldehyde with a novolak phenolic resin (A) obtained by the reaction of an aldehydes with a phenol in s ratio of [an aldehyde]/[a phenol]=0.3-0.6 (in molar ratio), as the indispensable component. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refractory binder suitable for refractory applications containing a phenol resin having a reduced amount of residual phenol (residual unreacted monomer) as an essential component.

[0002]

2. Description of the Related Art Phenolic resin has excellent heat resistance,
Utilizing adhesiveness, mechanical properties, electrical properties, price advantage, etc., molding materials of various base materials, binders for friction materials, binders for abrasives, adhesives for wood, binders for laminated materials, for molds Widely used as binders, binders for refractories, coating agents, epoxy resin curing agents, etc. Resol resin and novolac resin are generally known as the phenol resin. In recent years, it has been required to reduce pollution due to volatilization of unreacted phenols, aldehydes, or mononuclear components in a phenol resin from the viewpoint of protecting the atmospheric environment or protecting the human body environment. As for the novolac resin, a product containing 0.1% or less of unreacted monomer in the resin can be produced.

However, in the case of the resol resin, the situation is different from this, and since it has thermosetting property, it is difficult to remove the phenol monomer at high temperature. Further, it has been attempted to extract and remove unreacted monomers and mononuclear component with a solvent, but there are many problems such as the need to treat the solvent used at that time. Furthermore, reduction of monomer has also been studied by selecting reaction conditions. for that reason,
It is possible to reduce the amount of phenolic monomer under a certain condition, for example, when the molar ratio of phenols to aldehydes is 2.5 or more and the catalyst is used in a relatively large amount. In this case, a large amount of unreacted aldehydes remains, and it is difficult to practically obtain a product with a low odor except for some applications. Furthermore, not only unreacted monomers but also mononuclear components in which aldehydes have reacted with phenols are present in the resin in large amounts, so it volatilizes during the processing of the phenol resin and adheres to the processing and exhaust equipment.
Further, it may be exhausted to cause environmental pollution of the outside air.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a binder for refractories containing a resol-type phenol resin as an essential component, which can prevent the reduction of the substantial amount of the binder due to the pollution of working environment and the vaporization of monomer components. To provide.

[0005]

Means for Solving the Problems As a result of earnest studies, the present inventors have found that when a novolac type phenol resin and a resole type phenol resin derived from aldehydes are used as essential components for a refractory binder, The present invention has been completed and the present invention has been completed.

That is, according to the present invention, aldehydes and phenol are represented by [aldehydes] / [phenols] =
A novolac type phenolic resin (A) obtained by reacting at a ratio of 0.3 to 0.6 [molar ratio] and a resole type phenolic resin obtained by reacting an aldehyde are contained as essential components. Disclosed is a binder for a refractory material.

Further, in the present invention, aldehydes and phenol are mixed with [aldehydes] / [phenols] = 0.3
A novolac-type phenol resin (A) obtained by reacting at a ratio of up to 0.6 [molar ratio], and a resole resin obtained by reacting phenol and an aldehyde as essential components. A featured refractory binder is also provided.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The resole resin used in the present invention is
It can be obtained by reacting the novolak resin (A) with an aldehyde in the presence of a catalyst, or by reacting the novolak resin (A) with an aldehyde and a phenol. The novolak resin (A) is obtained by the reaction of phenols and aldehydes, and the reaction ratio of phenols and formaldehyde is [formaldehyde] / [phenols] = 0.3 to 0.6 [ The molar ratio] controls the content and molecular weight of the unreacted phenol remaining in the resin.

The novolac resin (A) is, for example,
It can be manufactured through the following steps. [Aldehydes] / [phenols] = 0.3 to 0.6 [molar ratio], phenols and aldehydes, and an acid as a catalyst are charged and reacted at 100 ° C. for 1 to 5 hours. Then, through normal pressure dehydration and reduced pressure dehydration steps, 180 to 230 ° C
At the temperature of 1, the unreacted phenol remaining in the novolac resin is removed. In this removing operation, the content of the unreacted phenol monomer remaining in the novolak resin is preferably as low as possible, and in practical use, it is preferably 1.0% by weight or less, and reduced to about 0.01% by weight. It is particularly preferable to keep it. The production is possible even if the molar ratio of [aldehydes] / [phenols] is less than 0.3,
As the molar ratio decreases, the yield deteriorates, which is economically disadvantageous. On the other hand, if it exceeds 0.6, it becomes difficult to adjust the molecular weight to an appropriate value for use in the present invention, which is not preferable.

The phenols used as the raw material are not particularly limited, and include, for example, phenol, alkylphenols such as cresol, xylenol, ethylphenol, butylphenol and octylphenol, polyhydric phenols such as resorcinol and catechol, and halogens. Phenol, phenylphenol, aminophenol and the like. In addition, these phenols are not limited to one kind in use, and two or more kinds can be used in combination. Here, resorcin and ordinary phenol monomers are good for obtaining a resole resin as a product, but it is practical to use a phenol monomer for obtaining an inexpensive product.

As the aldehydes of the present invention, formaldehyde, paraformaldehyde, formaldehyde such as trioxane, acetaldehyde, etc., which are commonly used in the production of phenol resins, are effective, and urotropin can also be used.

Acids used as a catalyst in the present invention include:
Acids generally used in the production of novolak resins can be used, for example, oxalic acid, hydrochloric acid, phosphoric acid, sulfuric acid, paratoluenesulfonic acid, phenolsulfonic acid, and zinc acetate, octyl which is a catalyst for high orthonovolac resins. Zinc acid or the like is used.

Next, the resol resin used in the present invention is
For example, it can be obtained by the following method. Obtained by a reaction of the above novolak resin (A) as a raw material with an aldehyde and an alkali metal or alkaline earth metal oxide, hydroxide, carbonate or amine, ammonia, zinc acetate or the like as a catalyst. You can
These catalysts may be reacted in one kind or in combination of two kinds. Further, for the purpose of neutralizing the catalyst, sulfuric acid, hydrochloric acid, phosphoric acid,
You may use paratoluene sulfonic acid etc.

In order to obtain a resole resin containing less unreacted monomer and mononuclear component, the low molecular weight novolac resin and the phenol monomer are used in combination, and the reaction is performed using an aldehyde and the same catalyst as above.

The resole resin used in the binder for a refractory of the present invention is preferably a resole resin containing no mononuclear component having 1 to 3 methylol groups bonded to the phenol nucleus.

The ratio of the novolac resin to the aldehyde in the production of the resole resin used in the present invention is C-13N.
The resin binding mole ratio measured by MR (C ¹³ -nuclear magnetic resonance absorption spectrum) is such that unreacted novolac resin component does not remain and physical properties such as curability are preferable [aldehydes] / [ [Novolak resin] is preferably 0.5 or more, and is preferably 4.0 or less from the viewpoint that no unreacted formaldehyde remains and it is preferable in terms of environmental measures.
Furthermore, [aldehydes] / [novolak resin] = 1.0
˜2.5 (molar ratio) is particularly preferred.

The amount of alkalis or alkaline earth metals used as a catalyst is 0.01 times or more moles of the catalyst with respect to the total number of moles of the novolak resin or the novolak resin and phenol used as a raw material, since the reaction proceeds smoothly. The amount is preferably 1.0 times or less because the reaction can be easily controlled, the storage stability of the product is not deteriorated by the catalyst, and the obtained resin does not become brittle.

As the method for producing the novolak resin (A), for example, oxalic acid is added as a reaction catalyst to a mixture of phenol and a 37% by weight aqueous formaldehyde solution, and the temperature in the reaction system is adjusted to 100 ° C. which is the boiling point of water. After reacting for 1 to 5 hours, distillation is carried out under atmospheric pressure up to 200 ° C., and further vacuum distillation is carried out. The amount of residual phenol in the resulting novolak resin is 1.0% by weight or less, preferably 0.1%. A novolak resin (A) having a weight not more than that is obtained. Next, the above-mentioned and manufacturing methods will be described more specifically.

37% by weight of the novolac resin (A)
4 as a catalyst in a mixture of aqueous formaldehyde solutions
Add sodium hydroxide with a concentration of 8% by weight to 50-80
At a temperature of ° C, the residual phenol content in the resole resin is 1.
The resole resin (B1) is obtained by reacting for 1 to 5 hours so that the amount becomes 0% by weight or less, preferably 0.1% by weight or less.

Phenol is further added to the novolac resin (A) and the aldehydes to react them. The reaction conditions are, for example, 50-80% by adding 48% by weight of sodium hydroxide to a mixture of novolac resin (A), phenol and a 37% by weight concentration of formaldehyde aqueous solution.
It is preferable that the residual amount of phenol is 5% by weight or less at a temperature of ° C. More preferably, the resol resin (B2) is obtained by reacting for 1 to 5 hours so as to be 3% by weight or less.

The refractory binder of the present invention includes the following forms. 1. Resol resin aqueous solution. 2. Resole resin solution: A resole resin solution obtained by removing water from the resole resin obtained by the above reaction and then dissolving it with an organic solvent, for example, alcohols such as methanol and glycols such as ethylene glycol and polyether glycol. 3. Water-dispersible resin solution: A water-dispersible resole resin solution that can be obtained by using a dispersant suitable for dispersing a phenol resin such as polyvinyl alcohol during the production of the resol resin obtained by the above reaction. 4. Solid resin: A high-melting solid polymer resol resin having a high melting point and little blocking after crushing, which is obtained by removing water and solvent by converting the molecular weight of ammonia or hexamethylenetetramine into a catalyst in the above reaction. . 5. Powder resin: Further, a powder obtained from the above solid resol resin.

A curing catalyst (alkaline substance or acid) may be added to these, if necessary. Examples of the alkaline substance include strong alkalis such as sodium hydroxide and amines, examples of the acids include p-toluenesulfonic acid, and the addition amount thereof is 0. 5 to 5 parts by weight is preferable.

A method for manufacturing a refractory (eg, brick) using the binder for refractory of the present invention will be described. The refractory binder of the present invention is not particularly limited as long as it can knead, mold, and cure the refractory aggregate in the above-described form, but, for example, in the case of an aqueous solution or an organic solvent solution,
The nonvolatile content measured at 135 ° C. is preferably 50 to 80% by weight, particularly preferably 60 to 70% by weight.

When a solid resin is used as a binder for refractories, it can be used as a mixture with an aggregate.

The above refractory aggregate is not particularly limited, and various aggregates can be used. For example, Mg
O, Al ₂ O ₃ , graphite, etc., are each 2.5 mm-1.
A particle size of 0 mm and a particle size of 1.0 mm or less are used in combination.

A uniform mixture is obtained by kneading the above refractory binder and the above aggregate. At this time, the blending amount of the refractory binder of the present invention is preferably 1 to 5 parts by weight, more preferably 2 to 4 parts by weight, per 100 parts by weight of the aggregate.

The compound thus obtained is molded in a mold and cured. At this time, a catalyst may be added to the mixture and cured at room temperature, or may be cured by heating at 100 to 200 ° C. Also, if necessary, 1000 ° C
You may bake before and after.

As a method for producing a refractory material using the refractory material binder of the present invention, for example, 100 parts by weight of an aggregate is mixed with 1 to 5 parts by weight of a resin liquid as a binder material and kneaded. After obtaining a uniform blend by, put the blend in a mold,
Press molding. Then, it heats as needed.

[0029]

EXAMPLES The present invention will be described in more detail with reference to Synthesis Examples, Examples and Comparative Examples. In the examples, “part” and “%” are parts by weight and% by weight, respectively. Also,
The number average molecular weight refers to a molecular weight converted into polystyrene having a known molecular weight by GPC (gel permeation chromatography). The residual phenol was measured by GPC when the residual phenol was 1% or more, and by gas chromatography when the residual phenol was less than 1%.

Synthesis Example 1 A stirrer and a thermometer were set in a 2-liter four-necked flask, and 941 g of phenol and 40.3 g of 37.2% formalin were added.
Then, the [phenol] / [formaldehyde] ratio was (10 mol) / (0.5 mol), and oxalic acid dihydrate was 8.82.
g, the temperature was raised to the reflux temperature (100 ° C.), and further 3
362.9 g of 7.2% formalin was added to [phenol] / [formaldehyde] = (10 mol) / (0.5 mol + 4.5).
(Molar) ratio was added dropwise over 1 hour. After reacting at reflux temperature for 3 hours, distillation was started and the temperature was raised to 180 ° C. After that, the temperature is raised to 220 ℃ and 50 torr (6.65 kPa).
Vacuum distillation was carried out for 1 hour to obtain a novolak resin having a softening point of 75 ° C. according to the B & R method, a free phenol amount of 0.3% measured by gas chromatography, and a number average molecular weight of 780 by GPC. The novolak resin was diluted with methanol to a solid content of 80% to obtain a novolak resin (X) as a methanol solution. Then this novolac resin
131.3 g of (X) and 60.8 g of 37% formalin were mixed well, 5.2 g of 48% NaOH aqueous solution was added thereto, and the temperature was raised to 70 ° C. After reacting at 70 ° C. for 4 hours, methanol was removed under reduced pressure at 60 ° C., and 27 g of water was added and cooled. An aqueous solution (I) of resol resin was obtained. The viscosity of this resin at 25 ° C is 2200 mPa · s.
The nonvolatile content at ° C was 72%. Since free phenol measured by GPC was 1% or less, it was 0.02% measured by gas chromatography. The bond molar ratio of this resin measured by C13-NMR was 1.4.
It was 9.

Synthetic Example 2 In the same manner as in Synthetic Example 1, 941 g of phenol and 40.3 g of 37.2% formalin were charged in a 2-liter four-necked flask, 8.82 g of oxalic acid dihydrate was added, and the reflux temperature was 100.
Increase the temperature to ℃ and add 37% formalin 202.7g to 1
It dripped over time. After reacting at reflux temperature for 5 hours, distillation was started and the temperature was raised to 180 ° C. Then the temperature is 220 ℃
Vacuum distillation at 1 to 50 torr (6.65 kPas)
The softening point of the ring and ball method (B & R method) was 45 ° C, and the amount of residual phenol measured by gas chromatography was 0.1.
%, GPC number average molecular weight 610, and C13-N
A novolak resin having a bond molar ratio of 0.75 determined by MR was obtained and diluted with methanol to a solid content of 80% (Y).
Got 1 of this novolac resin methanol solution (Y)
Mix well 31.3g and 37% formalin 36.5g,
To this, 5.0 g of sodium carbonate was added, and the temperature was raised to 70 ° C. After reacting at 70 ° C for 4 hours, vacuum dehydration at 60 ° C,
The mixture was cooled to room temperature and dissolved with 45 g of ethylene glycol to obtain an ethylene glycol solution (II) of resol resin. The viscosity of this resin is 2000 mPa · s (25 ℃),
The nonvolatile content at 150 ° C was 71%. The residual phenol content was 0.01% as measured by gas chromatography. The bond molar ratio of this resin measured by C-13 NMR was 1.05.

Synthesis Example 3 In the same manner as in Synthesis Example 1, 131.3 g of the novolak resin methanol solution (Y) obtained in Example 2 and 36.5 g of 37% formalin (0.45 mol) were placed in a 2-liter four-necked flask. ) Was mixed well, and 25% aqueous ammonia solution was added to this 4.
After adding 2 g and heating to 70 ° C and maintaining for 3 hours, 60 ° C
After removing water by vacuum distillation at 50, 50 g of methanol was added to obtain a resol resin methanol solution (III). The resin had a viscosity of 350 mPa · s, a nonvolatile content of 70% at 135 ° C., and a residual phenol content of 0.01% as measured by gas chromatography. The bond molar ratio of this resin determined by C13 NMR was 1.24.

Synthesis Example 4 A 2 liter four-necked flask was set with a stirrer and a thermometer, and 941 g (10 mol) of phenol and 1216 g (15 mol) of 37% formalin were mixed well, and 48% sodium hydroxide solution 47. After adding 1 g and heating to 80 ° C,
After reacting at 80 ° C. for 3 hours, the dehydration amount was adjusted by reducing the pressure at 60 ° C. so that the resin content was 70%. Viscosity is 800mP
An aqueous resol resin solution (a) of a · s was obtained. 1 of this resin
The nonvolatile content at 35 ° C was 70%. The residual phenol of this resin measured by GPC was 8.6%.

Synthetic Example 5 In the same manner as in Comparative Example 1, in a 2-liter four-necked flask, 941 g of phenol and 847 g of 37.2% formalin (1
(0.5 mol), 5.3 g of sodium carbonate was added, the temperature was raised to 80 ° C, and the mixture was reacted at 80 ° C for 4 hours, then 60 ° C
It was dehydrated under reduced pressure with and dissolved with 300 g of ethylene glycol. The viscosity of the obtained resol resin liquid (b) is 1800 m.
The nonvolatile content at Pa · s of 150 ° C. was 73%, and the residual phenol measured by GPC was 12.5%.

Synthesis Example 6 In the same manner as in Comparative Example 1, in a 2-liter four-necked flask, 941 g of phenol and 1010 g (17.2 g of 37.2% formalin) were added.
(2.5 mol) was mixed well, 38 g of 25% aqueous ammonium solution was added thereto, and the temperature was raised to 70 ° C. After reacting at 70 ° C for 4 hours, it was dehydrated under reduced pressure at 60 ° C and methanol 560 was added.
A resol resin solution (c) dissolved in g was obtained. The viscosity of this resol resin is 570 mPa · s, the nonvolatile content at 135 ° C is 70%, and the residual phenol measured by GPC is 8.
It was 2%.

The resole resins produced in the above-mentioned Synthesis Examples 1 to 3 were used as binders in comparison with the resins obtained in the Synthesis Examples 4 to 6 of the conventional production method. The following Examples 1 to 3 and Comparative Examples 1 to 3 are shown in Table 1. A general simulated molding for refractory applications was created. A representative brick type was a brick having a composition mainly composed of MgO. 45 parts by weight of MgO (2.5 mm to 1.0 mm) particles, 35 parts by weight of MgO (1.0 mm or less) particles, MgO (0.15 mm)
10 parts by weight of powder, 1 part of scaly graphite (1.0 mm or less)
A total of 100 parts by weight of the material composed of 0 parts by weight was used as an aggregate component. On the other hand, 3.5 parts by weight of a resin liquid as a binder was mixed and kneaded to obtain a uniform mixture. This compound was made into a molded product by applying a pressure of 1 t / cm ^{2 in} a mold capable of molding a cylindrical test piece having a diameter of 25 mm and a height of 25 mm. As the evaluation, the base strength, the dry strength, and the firing strength were determined by pressing from the tangential direction of the cylinder of the test piece to give the weight, and measuring the weight and comparing it with the volume to obtain the density.
(The unit of strength is Kgf / cm) Further, the base strength is the strength of the molded product taken out from the mold before curing, the dry strength is the strength after cooling at 150 ° C. for 2 hours after molding, and the strength after cooling, The firing strength was measured for each of the molded products that were heated in a nitrogen atmosphere at 800 ° C. for 3 hours and then cooled to room temperature.

The heating loss is a heating loss at 500 ° C. obtained by cooling a molded body heated at 150 ° C. for 4 hours to room temperature and then raising the temperature in air at 10 ° C./min. ) = 100 × (weight of molded body at 500 ° C.)
/ (Weight of molded product heated at 150 ° C. for 4 hours)

[0038]

[Table 1]

[0039]

EFFECTS OF THE INVENTION The binder for refractories of the present invention has the same performance as that of the conventional binders for refractories, has a small heating loss, and can provide a binder which does not pollute the working environment.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4G030 PA14                 4J033 CA01 CA02 CA03 CA11 CA12                       CA13 CA25 CA26 CB03 CB21                       CB25 CC01 CC03 CC04 CC07                       CC14 HA12 HA13 HB00 HB05

Claims (9)

[Claims] 1. A novolac-type phenol resin (A) obtained by reacting an aldehyde and a phenol at a ratio of [aldehydes] / [phenols] = 0.3 to 0.6 [molar ratio]. A binder for a refractory material, which contains, as an essential component, a resol-type phenol resin obtained by reacting an aldehyde with an aldehyde. 2. The binder for refractories according to claim 1, wherein the residual phenol content of the novolac resin (A) is 1% by weight or less. 3. The ratio of the bond between the novolak resin (A) obtained by C-13 NMR and the aldehyde in the resole resin is [aldehyde] / [novolak resin].
= 0.5-4.0 (molar ratio), The binder for refractories according to claim 1 or 2. 4. The refractory binder according to claim 3, wherein the novolac resin (A) has a number average molecular weight of 500 to 800 as measured by GPC. 5. The resol type phenol resin has a pH of 4 to 4 in the presence of a catalyst, the novolac resin (A) and aldehydes.
The binder for refractories according to claim 1, which is reacted under the condition of 12. 6. The binder for refractories according to claim 4 or 5, wherein the residual phenol amount of the resol type phenol resin is 1% by weight or less. 7. A novolac type phenolic resin (A) obtained by reacting an aldehyde and a phenol at a ratio of [aldehydes] / [phenols] = 0.3 to 0.6 [molar ratio]. And a resol resin obtained by reacting phenol with aldehydes as an essential component. 8. The refractory binder according to claim 7, wherein the residual amount of phenol in the resol resin is 5% by weight or less. 9. An aqueous solution, a glycol solution, an alcohol solution of the resol resin according to claim 1.
Alternatively, a binder for refractory used as a powder.