JPH01315411A - Production of quick-curable, ammonia-free solid resol resin - Google Patents

Abstract

PURPOSE:To easily obtain the title resin prevented from gelling, good in storage stability by incorporating the reaction system, at any point after initiation of the condensation, with a second phenol more reactive than the phenol as a raw material. CONSTITUTION:After initiation of condensation between (A) a phenol (e.g., phenol, cresol) and (B) an aldehyde (e.g., formaldehyde glyoxal) as two raw materials for a solid resol resin, the reaction system is incorporated, at any point, with (C) a second phenol or naphthol more reactive than the component A followed by reaction, normally at 60-120 deg.C. Subsequently, the resulting reaction mixture is dehydrated and condensed, thus obtaining the objective resin. The component C is e.g., resorcin, beta-naphthol in case the component A is phenol.

Description

Detailed Description of the Invention [Object of the Invention] (Industrial Application Field) The present invention relates to a method for producing a fast-curing ammonia-free solid resol resin that can be used as a binder for shell molds, molding materials, etc. It is something to do.

(Prior Art) Phenolic resins are broadly classified into rack-type phenolic resins and resol W resins, both of which have excellent performance and workability as binders for organic or inorganic substrates. These are used as binders in a wide range of fields, such as shell molds, refractories such as bricks, fiber mats and sheets, and molding materials. When using a phenolic resin as the agent, it is preferable to use a solid one from the viewpoint of workability because it is easy to handle. Traditionally, solid 7
Enol resin is used.

Tumerac resin does not harden even when heated alone like resol resin, so it is usually combined with a curing agent such as hexamethylenetetramine or paraform to i-form it. However, when such a curing agent is used, harmful gases are generated during the crosslinking reaction with the resin, causing a deterioration of the working environment. Furthermore, when Tumerac resin and hexamethylenetetramine are used together as a molding material for electrical parts, ammonia remains in the molded product and corrodes the metal parts inserted therein.

On the other hand, since resol resins have self-curing properties, there is no need to use a curing agent, and there are far fewer concerns about corrosion and environmental pollution than with novolac resins that use hexamethylenetetramine as a curing agent. When trying to produce a solid resol resin, a resol resin using ammonia as a catalyst is the easiest to solidify and is the easiest to produce. However, when a solid resol resin containing ammonia is used as a molding material, residual ammonia in the molded product is unavoidable, and there is no solution during corrosion. Therefore, expectations for solid resol resins that do not use ammonia have increased in recent years.

(Problem to be solved by the invention) As an industrial method of using solid resol resin.

Conventionally, various methods have been proposed. The most common method is to advance the reaction to a predetermined degree of condensation in a reaction vessel, and then perform dehydration and condensation under reduced pressure. Cooled steel belt or cooling i'? This is a method of taking it out on top of the container.

However, when this method is applied to the ammonia 7-lead solid resol resin Ka, it is extremely difficult to control the reaction because the reaction rate increases in the dehydration and concentration step under reduced pressure after the main reaction between phenol and formaldehyde. ,
It is difficult to judge a predetermined end point, and when trying to obtain a high-melting-point, fast-curing resin, it often tends to gel. Moreover, when ammonia-free solid resol resin is produced industrially by the above method, the fluidity is poor during thickening, and the panning process requires a long time for rounding.
The drawback was that the properties of the resin were different between the front and rear parts of the pan-out. However, if the reaction is stopped at a low degree of condensation to prevent gelation, only a semi-solid ammonia-free resol solid resin with a low melting point and slow curing is obtained, which causes blocking during storage and has poor storage stability. There wasn't.

Further, conventional resol resins have inferior curability at low temperatures (150 to 200°C) compared to Tumerac resins using curing agents, and various methods have been proposed to improve the curability.

For example, a method of blending a nogelac type resorcin resin with a solid resol resin (Japanese Patent Application Laid-open No. 70150/1983).

A method of adding highly reactive phenols or acids to a solid resol resin (% open/close No. 54-28357) is known, and the above-mentioned Japanese Patent Application Laid-open No. 54-28357 describes a method for producing a solid resol resin. A method of adding phenol RA in the process is also described.

However, none of these methods achieved improvement in curability because the solid resol resin itself, which is a preliminary step to producing a composition t-S with improved curability, cannot be stably obtained.

In addition, in the process of producing solid resol resins, when highly reactive phenols, acids, or phenolic resins are added, the progress of the reaction is hindered, and the reaction is abnormally accelerated, resulting in partial polymerization and gelation. However, it is known that only solid resol resins can be produced that do not gel but have significantly poor meltability.

Therefore, the present inventors have attempted to improve the above-mentioned drawbacks in the production of conventional solid resol resins. It has been shown that by adding other phenols or naphthols at any stage after the start of condensation and reacting, gelation of the resin can be prevented and a fast-curing solid resol resin with excellent storage stability can be easily produced. Heading 1 The present invention has been completed.

[Structure of the invention]

(Means for Solving the Problems) That is, the present invention provides a method for producing a solid resol resin in which phenols and aldehydes are reacted and then dehydrated and concentrated. The present invention provides a method for producing a fast-curing ammonia-free solid resol resin, which is characterized by adding and reacting other highly reactive seven enols or naphthols.

Phenols as raw materials for the solid resol resin used in the present invention include phenol, cresol, butylphenol, nonylphenol, noalkylphenols such as xylenol, halodanated phenols such as chlorophenol and bromophenol, catechol, resorcinol,
Hydroquinone, bisphenol F, bisphenol A
Typical examples include divalent phenols such as, other phenolic hydroxyl group-containing hexamers, and their di- or trinuclear oligomers, but they are not limited to these, and these can be used alone. However, it may be used in conjunction with two or more vertebrae.

Next, the aldehydes used in the present invention include formaldehyde, paraformaldehyde, butyraldehyde,
Formaldehyde supply materials such as hydroxybenzaldehyde, glyoxal, furfural, and acetals of formaldehyde such as methylal are representative examples, but are highly reactive and can shorten the reaction time, although they are not limited to these. Preferably.

Although the catalyst used in the present invention is not particularly specified, it is usually an alkaline catalyst or a neutral metal salt catalyst, and specifically, sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide, Alkali metal and alkaline earth metal hydroxides such as lithium hydroxide, magnesium hydroxide, etc.

Alkaline earth metal oxides such as magnesium oxide and calcium oxide, tertiary and secondary amines such as triethylamine, diethylamine, triethanolamine, dimethylethanolamine, zinc acetate, barium acetate, manganese acetate, zinc chloride, chloride Magnesium, zinc naphthenate, cobalt naphthenate, sodium carbonate, sodium bicarbonate.

Potassium bicarbonate, zinc borate, manganese borate.

Examples include barium sulfate, manganese sulfate, iron oxalate, etc. When promoting methylolation, alkaline catalysts are preferred, and when promoting benzyl etherification, neutral metal salts are preferred.

If it is a catalyst that promotes p/zyl etherification.

It is not limited to the above. Furthermore, it is also possible to use the above catalysts in combination.

In the present invention, the molar ratio of aldehydes to phenols when producing resol resin T- is F, where the number of moles of phenols used is P, and the number of moles of aldehydes used is F.
When expressed as /P, the value of F/P is 1, 1 to 3.0, preferably 1.3 to 2.8. If the F/P value exceeds 3.0, polymerization progresses during the dehydration condensation process and gelation tends to occur, making it difficult to control the reaction, while if it is less than 1.1, dehydration and concentration will occur. The resulting solid resol resin has a low melting point and is prone to blocking.

The reaction temperature when producing these resol resins may be adjusted as appropriate within the temperature range of about 60 to 120°C, similarly to when producing ordinary resol resins.

What are the other seven enols or naphthols that are more reactive than the phenols in the present invention?

Phenols used as raw materials for solid resol resin)
It also refers to other phenols or naphthols that have a high reaction rate with formaldehyde.

(Hereinafter, it will be abbreviated as 1 highly reactive additive.) The reaction rate referred to here is when phenols and aldehydes are mixed at 40 to 120°C in the presence of a catalyst. 2 refers to the rate at which 2 is consumed in the reaction (hereinafter abbreviated as half-life), and the half-life is determined by selecting two arbitrary compounds from phenols and reacting with formaldehyde in the presence of the above-mentioned perfusion catalyst. This can be easily determined by carrying out the reaction and measuring the amount of formaldehyde remaining.

As the highly reactive additive, any of the phenols or naphthols used as raw materials for the solid resol resin can be used.

The amount of highly reactive additives used is not particularly limited, but usually o, oos per mole of phenol.
~0.7 mol, particularly preferably 0.01 to 0.30 mol. If the amount used is less than o, oos mole, it tends to be difficult to make it into a final solid.
If the amount exceeds 7 mols, the characteristics of the resol resin, which is produced by reacting target phenols and aldehydes in the presence of a catalyst, tend to change significantly. Also, the number of moles of formaldehyde used/(number of moles of phenol as a raw material + number of moles of highly reactive additive) ≧ 1.1.
need to be adjusted.

Incidentally, the amount of the highly reactive additive contained in the solid resol resin can be easily determined by NMR, FT-IR, or the like.

The highly reactive additive may be added at any stage of the reaction, for example at the following stage.

■ The stage from the start of the reaction between phenols and aldehydes to the initial condensation of resol resin.

■ The stage of the initial condensate of resol resin, which is a reaction between phenols and aldehydes in the presence of a catalyst.

(The initial condensate of resol resin may be anything that is called a normal initial condensate, but in the present invention, unreacted phenols are 70 to 40% by weight of the total weight of phenols as raw materials for solid resol resin. ) ■ Unreacted phenols account for 40% by weight of the total weight of phenols used as raw materials for solid resol resin.
condensate (hereinafter abbreviated as liquid resol) in which the gelation time at 150° C. is 15 seconds or more.

(However, the gelation time at 150°C is based on JISK691
It was measured by the method specified in 0. It refers to the time (seconds) it takes for the resin to harden at 150°C. ) In addition, as the initial compound and liquid resol of the above resol resin, either water-soluble or alcohol-soluble may be used as long as it is produced by the above-mentioned F/P.Furthermore, those obtained by neutralizing these with acid may also be used. can.

Next, the present invention will be explained with reference to Examples and Comparative Examples.

Hereinafter, all 51 parts shall mean 1 part by weight.

〔Example〕

Example 1 500, 9, 41% formaldehyde aqueous solution of phenol 6.151 in a four-bottle flask equipped with a condenser and a stirrer
259f of 50% potassium hydroxide was added with stirring, and the reaction was carried out at 70°C until the water dilution capacity reached 100%. Resorcin T509 was added thereto and allowed to react for 30 minutes, then heated to 110° C. under reduced pressure at 700 μHg while being dehydrated, and taken out from the flask. The resulting resin had a melting point of 82°C.

Gelation time at 150°C was 55 seconds.

Example 2 500 g of phenol and 920.5 J of a 41% formaldehyde aqueous solution were placed in a four-bottle flask equipped with a condenser and a stirring device.
Add barium hydroxide octahydrate while stirring.
0.9 was added, and the reaction was carried out at 75°C until the water dilution capacity reached 300 mw. After 100y of resorcinol was added thereto and allowed to react for 30 minutes, the mixture was heated to 105° C. under reduced pressure at 710 μHg and removed from the flask. The resulting resin had a melting point of 86°C and a gelation time of 48 seconds at 150°C.

Example 3 The same operation as in Example 2 was carried out, except that after the main reaction in Example 2, the resin solution was neutralized with 10% sulfuric acid and the pH of the resin solution was 6.7 KL. The resulting resin had a melting point of 78°C and a gelation time of 62 seconds at 150°C.

Example 4 500 g of phenol and 41% formaldehyde 7009 were placed in a four-bottle flask equipped with a condenser and a stirrer, and 5 fI of sodium carbonate was added while stirring, and the reaction was carried out at 80° C. until the water dilution capacity reached 150% by weight. Resorcin T-259 was added thereto and the mixture was allowed to react for 10 minutes, then the temperature was raised to 110° C. under reduced pressure at 700 saw Hg while dehydrating, and the mixture was taken out from the flask. The resulting resin had a melting point of 83°C and a gelation time of 49 seconds at 150°C.

Example 5 500 g of m-cresol and 280 It of 80% paraform were placed in a four-bottle flask equipped with a condenser and a stirrer, and while stirring, 1101 T of magnesium oxide was added thereto, and the mixture was allowed to react at 80 DEG C. for 3 hours. After adding resorcin T-75,9 and allowing it to react for 10 minutes, it was heated to 720 Hg under reduced pressure.
The temperature was raised to 112° C. while dehydrating, and the flask was taken out. The resulting resin had a melting point of 80°C and a gelation time of 60 seconds at 150°C.

Example 6゜Phenol ## in a 94-hole flask equipped with a condenser and a stirring device
500. V, 80%/+U# Shim 330F'ir was placed, and 10.9 g of zinc acetate/dihydrate water was added with stirring, and the mixture was reacted under reflux for 5 hours. There resorcin t-100F
After additionally holding and reacting for 30 minutes, 719W under reduced pressure
The temperature was raised to 115° C. while dehydrating with Hg, and the flask was taken out. The resulting resin had a melting point of 74°C and a gelation time of 65 seconds at 150°C.

Example 7 500. F, 41% formal f human aqueous solution 750. Add magnesium oxide while stirring.
9 was added, and the mixture was reacted at 80°C for 7 hours. After adding resorcin t-sog to it and allowing it to react for 10 minutes,
The temperature was raised to 110°C under reduced pressure at 700 ssHg while dehydrating, and the mixture was taken out from the flask. The resulting resin had a melting point of 86°C and a gelation time of 65 seconds at 150°C.

Example 8 752 g of phenol and 9411 t of 371% formaldehyde were placed in a 94-bottle flask equipped with a condenser and a stirring device, and 30 yt of 48% barium hydroxide was added while stirring.
The reaction was carried out at 0°C for 3.5 hours. There m-cresol 12
0.9, held for 30 minutes, and then heated to 690°C under reduced pressure.
Dehydration was carried out at mHf, and when the temperature was raised to 105°C, it was quickly taken out from the flask and cooled. The resulting resin had a melting point of 78°C and a gelation time of 4 at 150°C.
It was 8 seconds.

Example 9゜ Put 7 enol 752 and 100 g of 91.37% formaldehyde into a four-loaf flask equipped with a condenser and stirrer, add 25 pi of potassium hydroxide with stirring, and react at 70°C until the dilution capacity of 5% saline solution reaches 750%. did. There, β−
Naphthol 130F? Addition, dissolution, water dilution capacity 20
It was maintained at 0%. Next, dehydration and concentration were carried out under reduced pressure at 690 μHg, and when the temperature was raised to 100° C., the flask was quickly taken out and cooled. The resulting resin had a melting point of 81°C and a gelation time of 45 seconds at 150°C.

Example 10 7/-Lua in a four-loaf flask equipped with a condenser and a stirrer 52. lil, 37% ho/I/ A 7 lej
? Add Nido 1040I and add 30% calcium hydroxide while stirring. lil'i was added, and the mixture was reacted at 75°C for 4 hours. After adding resorcinol sogt and holding for 15 minutes,
Dehydration and concentration were performed under reduced pressure at 690 mHg, and when the temperature was raised to 110°C, it was quickly taken out of the flask and cooled. The resulting resin had a melting point of 80°C and a gelation time of 50 seconds at 150°C.

Example 11 300 g of bisphenol A and 300 g of 41% formaldehyde were placed in a four-loaf flask equipped with a condenser and a stirrer, and 10.9 g of lithium hydroxide was boiled while stirring, and the mixture was heated to 80°C.
The reaction was carried out for 5 hours. Add Resolcif F309 to it, hold it for 10 minutes to react, and then transfer it to 700 m under reduced pressure.
The temperature was raised to 110° C. while dehydrating with Hg, and the mixture was taken out from the flask. The resulting resin had a melting point of 84°C and a gelation time of 70 seconds at 150°C.

Comparative Example 1 The same operation as in Example 1 was carried out except that the operation of adding 50 g of resorcin for reaction was not carried out. As a result, when the temperature was increased while dehydrating under reduced pressure, gelation occurred rapidly at around 100°C. Until then, the melting point was below room temperature.

Comparative Example 2 In Example 2, resorcinol 100. i- The same operation as in Example 2 was performed except that the additional reaction operation was not performed. As a result, when the temperature was increased while dehydrating under reduced pressure, gelation rapidly occurred at around 100°C. Until then, the melting point was below room temperature.

Comparative Example 3 The same operations as in Example 3 were carried out except that the operation of adding 100 g of Resolcif to react was not carried out. As a result, gelation occurred during dehydration and heating to 105° C. and removal from the flask. Until then, the melting point was below room temperature.

Comparative Example 4 The same operation as in Example 4 was carried out except that the operation of adding 25.9 ft of resorcin and reacting it was not performed. As a result, when the temperature was increased while dehydrating under reduced pressure, the viscosity increased around 110°C, and stirring became difficult, so it was removed from the flask.

The resulting resin had a melting point of 47°C and a gelation time of 1 at 150°C.
It took 45 seconds.

The nine resin obtained in Example 4 had a number average molecular weight of 657 in terms of polystyrene, a weight average molecular weight of 2149, and a melting point of 83.
It was ℃. On the other hand, the resin obtained in Comparative Example 4
The number average molecular weight is 892, the weight average molecular weight is 5230,
Although the molecular weight was higher than that of the resin of Example 4, the melting point was as low as 47°C.

Comparative Example 5 The same operations as in Example were carried out except that 75 g of hydroquinone was added instead of 75 g of resorcinol in Example 5. As a result, when the temperature was increased while dehydrating under reduced pressure, gelation occurred rapidly at around 102°C. Until then, the melting point was below room temperature.

Comparative Example 6 In Example 8, m-cresol 120. ! Example 8 except that the operation of adding ii'Th and reacting was not performed.
I performed a similar operation. As a result, when the temperature was raised to 90° C. in the dehydration and concentration step, gelation suddenly occurred. Until then, the melting point was below 40°C.

Comparative Example 7゜In Example 9, β-naphthol 130. The same operation as in Example 9 was carried out, except that the operation of exposing F to react was not carried out at all. As a result, in the dehydration and concentration process, 9
When the temperature was raised to 0°C, gelation suddenly occurred at the 9th point. Until then, the melting point was below 40°C.

Comparative Example 8.10゜All operations were carried out in the same manner as in Example 10, except that in Example 1O, the operation of additionally reacting resorcinol.
It suddenly turned into a gel when the temperature was raised to . Until then, the melting point was below 40°C.

Comparative Example 9: Phenol 752, 17.37% formaldehyde aqueous solution 1005 was added to a four-bottle flask equipped with a condenser and a stirring device.
．． 9'? Add 25% ammonia water soluble i9 while stirring.
In addition to the refractive index n; Then, the mixture was completely dehydrated and concentrated under reduced pressure at 690 mHg, and when the temperature was raised to 110111:'t, it was quickly taken out of the flask and cooled. The resulting ammonia-catalyzed solid resol resin had a melting point of 65° C. and a heating time of 82 seconds at 150° C.

[Application example]

Application Examples 1 to 3 and Comparative Application Example 1 Each of the solid resol resins obtained in Examples 1.2.4 and Comparative Example 4 was completely pulverized to evaluate its performance as a binder for shell mode molds. 160 g of flattary silica sand heated to 140° C. and resin were placed in a speed mixer for kneading foundry sand, mixed for 60 seconds, and kneaded for 20 seconds while adding water Is og and cooling. Thereafter, 8 g of calcium stearate was added, and the mixture was further kneaded for 20 seconds to perform resin-coated sand molding. The performance of the resin coated sand for shell molds obtained here is shown in Table 1 below.

〔Test items〕

Bending strength: Measured according to JISK6910.

Melting point...JACT test method C-1 Hot tensile strength...JACT test method 5M-10#Bend amount...Resin coated sand is filled in a mold at a specified temperature and baked for 20 seconds, then After 101 minutes, the test piece was taken out, a 200 g weight was placed on the center of the test piece, and the amount of deflection was read using a dial gauge. The test piece is 50 W x 150 m x 5 m, and the deflection measurement span is 110 m.

/ , 7/ As is clear from Table 1, the resin coated sand using the solid resol resin obtained by the production method of the present invention is superior in all respects to that using the conventional solid resol resin. It is found that it has excellent fast curing properties, especially from the hot tensile strength and bend amount values.

Application Examples 4 to 5 and Comparative Application Example 2 Each of the solid resol resins obtained in Examples 3 and 8 was pulverized to prepare a molding material, and ammonia catalyst solid -
The performance of the sol resin was also fully evaluated.

Solid resol resin i-b, 900g of wood flour, and 20g of magnesium oxide! A mixture of I and 10y of zinc stearate was kneaded in a co-kneader, then kneaded with a roll, taken out, cooled and solidified, and pulverized to prepare a molding material as shown in Table 2.

The performance of the molding material obtained here is shown in Table 2 below.

〔Test items〕

Moldability: Measured according to 5.4 of JIS K6911.

Specific gravity of molded material: Measured according to JI8-6911, 5.28.1.

Bending strength: Measured according to 5.17.2 of JIS K6911.

Impact strength: Measured according to 5.20.2 of JIS K6911.

Insulation resistance: Measured according to 5.12.2 of JIS K6911.

Amount of free ammonia: Measured according to ASTM D834-61.

/ / Donilla Table 2 Molding materials using the resin obtained by the production method of the present invention are as follows:
No ammonia gas is generated during molding, which will not cause corrosion of the metal parts inserted into the mold or molded product.

〔Effect of the invention〕

As described above, according to the production method of the present invention, an ammonia-free solid resol resin can be produced efficiently and stably.

The ammonia-free solid resol resin obtained by the production method of the present invention has a uniform molecular weight compared to conventional resins, so it does not cause cracking due to its high melting point, has good storage stability, and has fast curing properties. It is.

That is, the present invention has a particularly remarkable effect in that it solves the difficulty of controlling the reaction in the conventional ammonia-free solid resol resin spreading method, and also solves the drawback that the curing speed of the resol resin is inherently slow. It is very useful in applications such as adhesives, foundry binders, molding materials binders, etc.

Claims (1)

[Claims] 1. After reacting phenols and aldehydes,
A method for producing a solid resol resin by dehydration and concentration, characterized in that other phenols or naphthols, which are more reactive than the phenols, are added and reacted at any stage after the start of condensation. A method for producing ammonia-free solid resol resin. 2. A claim in which the time of addition of other phenols or naphthols, which are more reactive than the phenols, is longer than 15 seconds from the initial condensate of the resol resin to gelation at 150°C. The manufacturing method according to item 1. 3. Claim 1, wherein the other phenols or naphthols that are more reactive than the phenols are at least one compound selected from resorcinol, m-cresol, benzenetriol, α-naphthol, or β-naphthol. Manufacturing method described.