JPH0611781B2 - Method for producing highly reactive aromatic hydrocarbon / formaldehyde resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an aromatic hydrocarbon formaldehyde resin, particularly phenols, aliphatic carboxylic acids, aromatic carboxylic acids,
Alternatively, it contains a large amount of reaction active groups that are highly reactive with a compound having active hydrogen such as amine, and the content of an inactive diallylmethane component which is inactive during the reaction with the compound having active hydrogen is extremely small. The present invention relates to a highly reactive aromatic hydrocarbon formaldehyde resin and a method for producing the same.

[Prior art and its problems]

It is well known that an aromatic hydrocarbon formaldehyde resin is obtained by reacting an aromatic hydrocarbon with formaldehyde in the presence of an acid catalyst such as sulfuric acid. The aromatic hydrocarbon-formaldehyde resin is a mixture of general consisting numerous molecular species to the oligomer, methylene linkage between the aromatic nucleus (-CH ₂ -), dimethylene ether bond _{(-CH 2 O-CH 2 -} ), Acetal bond 1 to 2 or more and having a methylol group (—CH ₂ OH) or a methoxymethyl group (—CH ₂ OCH ₃ ) at the end of the molecule, or not having 1 to 8
It is composed of nucleolar oligomers. Such an aromatic hydrocarbon formaldehyde resin is prepared by reacting a compound having active hydrogen such as phenols, aliphatic carboxylic acids, aromatic carboxylic acids or amines in the presence of a catalyst with various modified aromatic hydrocarbons. It is known to give hydrocarbon resins such as phenol-modified aromatic hydrocarbon resins, unsaturated carboxylic acid-modified aromatic hydrocarbon resins, aniline-modified aromatic hydrocarbon resins, and the like. Is used for.
(R. Wegler, Angew chem. A / 60.88 (1948): Im
oto, M. et al. Makromol. Chem. 43, 189 (1961): Br
itish.Plastics 9.564 (1965): Tanigaki, Polymer Chemistry 12.2.35 (1955)) The reaction between an aromatic hydrocarbon formaldehyde resin and the above-mentioned compound having active hydrogen is carried out in an aromatic hydrocarbon formaldehyde resin. -CH ₂ O-CH ₂ - bond, It is known that oxygen-containing groups such as —CH ₂ OH group and —CH ₂ OCH ₃ group are involved.

As a means for knowing the concentration of the reactive group in the aromatic hydrocarbon formaldehyde resin, for example, the following method is generally used for the reaction with phenol. That is, after reacting the aromatic hydrocarbon formaldehyde resin with phenol, the amount of unreacted phenol in the reaction product is measured, and from this, the maximum amount of phenol that can react with the aromatic hydrocarbon formaldehyde resin is obtained in reverse. This is a method of expressing it as the number of phenols. However, since phenol has three reactive sites in one molecule, 1 mol of reactive groups in the aromatic hydrocarbon formaldehyde resin may not correspond to 1 mol of phenol. It is insufficient to know the degree of reactivity without accurately expressing the number of groups.

The present inventors examined a method for measuring the concentration of a reactive group in an aromatic hydrocarbon formaldehyde resin and found a method based on "xylenol number" as an index for knowing the degree of reactivity. It has been found that this xylenol number adequately represents the reactivity of the aromatic hydrocarbon formaldehyde resin.

The xylenol value is a value represented by the number of moles of 2,6-xylenol reacted per 1 kg of the aromatic hydrocarbon formaldehyde resin when the aromatic hydrocarbon formaldehyde resin and 2,6, xylenol are reacted.
This is calculated by the formula described later. The higher the xylenol value, the more reactive it is.

On the other hand, in the aromatic hydrocarbon formaldehyde resin, a component in which nuclei are bound by a methylene bond, that is, a diallylmethane component (for example, ) Is also included. This diallylmethane component does not react with the compound having active hydrogen as described above, remains as an unreacted component in the modified resin, and becomes one of the factors that deteriorate the physical properties of the cured resin obtained from the modified resin, It is preferable that the resin content is as small as possible.

Here, looking at a commercially available xylene-formaldehyde resin, which is a typical aromatic hydrocarbon formaldehyde resin, the number average molecular weight is 450 to 600, the average number of cores is 4 to 5, and the xylenol value is 9. 5-1
It is 0.5 mol / Kg.

In addition, -CH ₂ OH, -CH ₂ OC bound to the terminal aromatic nucleus of the molecule
The number of H ₃ , -CH ₂ OCH ₂ OCH ₃ groups is determined by the nuclear magnetic resonance method ( ¹ H-NM
It was about 1 per molecule as measured by R). In addition, the aromatic nuclei are bound by methylene bonds and the component having no substituent at the terminal of the molecule, that is, the diallylmethane component is added to 10 to 15 parts.
Contains by weight percent. Such an aromatic hydrocarbon formaldehyde resin has poor reactivity with the above-mentioned compound having active hydrogen, and is a modified aromatic hydrocarbon obtained by reacting with a phenol, an aliphatic carboxylic acid, an aromatic carboxylic acid or an amine. The cured product obtained from the resin has insufficient physical properties such as mechanical strength and heat resistance.

[Means for solving problems]

An object of the present invention is to provide an aromatic hydrocarbon formaldehyde resin which is highly reactive with compounds having active hydrogen such as phenols, aliphatic carboxylic acids, aromatic carboxylic acids or amines.

As a result of various studies by the present inventors, it was obtained by reacting with a compound having active hydrogen such as phenols, aliphatic carboxylic acids, aromatic carboxylic acids, or amines and capable of reacting with an aromatic hydrocarbon formaldehyde resin. In order to give a cured product of the modified aromatic hydrocarbon resin having excellent mechanical strength and heat resistance, the aromatic hydrocarbon formaldehyde resin contains 5% by weight of the diallylmethane component in the resin.
The amount is as low as possible, the xylenol value is high at least 15 mol / Kg, and -CH ₂ OH groups and -CH ₂ OCH ₃ are present at both ends of the molecule.
It has been found that the presence of reactive groups such as groups is essential. However, such an aromatic hydrocarbon formaldehyde resin has not existed in the past.

As one of the aromatics for obtaining an aromatic hydrocarbon formaldehyde resin having a high xylenol value, for example, by decreasing the acid catalyst concentration (for example, sulfuric acid concentration) in the reaction between the aromatic hydrocarbon and formaldehyde, or by lowering the reaction temperature. A reaction method is generally considered. However, in the aromatic hydrocarbon formaldehyde resin obtained by such a method, the content of the low-molecular-weight diallylmethane component in the resin is large, and the content of the reactive group at the molecular end is low, so that the desired high reaction Aromatic hydrocarbon formaldehyde resins with no properties are obtained.

The present inventors have found that the aromatic hydrocarbon formaldehyde resin has excellent reactivity with compounds having active hydrogen such as phenols, aliphatic carboxylic acids, aromatic carboxylic acids, and amines, and has a content of diallylmethane component as low as possible. When reacting formaldehyde with aromatic hydrocarbon, the molar ratio of formaldehyde to aromatic hydrocarbon is 2.0 to 5.0, and the concentration of sulfuric acid is 15 to 3
The reaction rate of formaldehyde is 50 to 70 mol% at a reaction temperature of 80 to 110 ° C. in 4 to 8 hours.
It was found that an aromatic hydrocarbon formaldehyde resin having a desired reactivity and a low content of diallylmethane component can be obtained by controlling the reaction within the range of the above range.

The aromatic hydrocarbon formaldehyde resin obtained by the above method has a xylenol value of at least 15 mol / Kg, has a large number of reactive groups, and has CH ₂ OH at both ends of the molecule.
Group, a -CH ₂ OCH ₃ group, or a -CH ₂ OCH ₂ OCH ₃ group is essential as a reactive group, and the content of the diallylmethane component is 5% by weight or less.

Such an aromatic hydrocarbon formaldehyde resin of the present invention is excellent in the reaction with the compound having active hydrogen described above, and the modified aromatic hydrocarbon resin obtained by the reaction with the compound having active hydrogen described above is It gives a cured product with excellent mechanical strength and heat resistance as compared with the case of using a conventional aromatic hydrocarbon formaldehyde resin.

In the present invention, it is extremely important to suppress the reaction rate of formaldehyde within the range of 50 to 70 mol% as described above, and to achieve this reaction rate in 4 to 8 hours. This is an extremely mild condition as compared with the conventional manufacturing method.

In order to achieve the above requirements, one of the preferable methods is to carry out the reaction while maintaining the interface between the water layer and the oil layer (resin layer).

One way to do this is to make the stirring speed sufficiently slower than the conventional method. It is difficult to unconditionally determine the stirring speed because it depends on the size of the reactor, the shape of the stirrer, etc., but for example, a laboratory scale reactor (about 2 to 5) is used and an anchor-type stirrer is used. When used, it is about 150-260 r. p. m is about m, and when the capacity of the reactor becomes large as shown in Examples described later, the stirring speed is further slowed down but does not change in proportion to the capacity of the reactor. 50 to 70 mol% in 4 to 8 hours
The stirring speed to be suppressed within the range is appropriately selected. When the reaction rate of formaldehyde is set to a predetermined reaction rate in a time shorter than 4 hours, the amount of diallyl methane component increases in the produced aromatic hydrocarbon formaldehyde resin and the end groups present in one molecule Is significantly less than 2, which is not preferable. On the other hand, when the reaction rate of formaldehyde is set to a predetermined reaction rate for more than 8 hours, a gel is formed in the produced resin, which is not preferable.

In the method for obtaining the aromatic hydrocarbon formaldehyde resin of the present invention, the reaction system has a boiling point range of 90 to 15 during the reaction.
An inert solvent at 0 ° C., such as ethylbenzene, hexane, heptane, octane, or a mixture thereof,
Addition of 5 to 50% by weight with respect to the aromatic hydrocarbon has the effect of lowering the viscosity and specific gravity of the produced resin and making it easier to maintain the interface between the oil layer and the water layer, and the reaction rate is controlled by the stirring speed. Very effective for. If the amount of the inert solvent used is less than 5% by weight, the effect of addition does not appear. On the other hand, the use of an amount exceeding 50% by weight is one of the factors that cause formation of gel in the produced resin, which is not preferable. . If the boiling point of the inert solvent used is lower than 90 ° C., the reflux temperature is lowered during the reaction, and the reaction time tends to be long, which is not preferable.
If the temperature is higher than 0 ° C, it may remain in the resin formed after the reaction, which is not preferable.

In addition, in the case of using an inert solvent as described above in the reaction, when separating the resin formed after the reaction from the aqueous layer, it is necessary to use a diluent solvent to facilitate the separation of the resin layer and the aqueous layer. However, in this case, there is also an advantage that the working process can be simplified without adding a solvent again.

In the present invention, it is important to make the reaction rate of formaldehyde within a predetermined range by requiring a predetermined time as described above.
In addition, the molar ratio of aromatic hydrocarbon to formaldehyde, the concentration of sulfuric acid as a catalyst, the reaction temperature, etc. are also important matters for producing the highly reactive aromatic hydrocarbon formaldehyde resin which is the object of the present invention. . The molar ratio of formaldehyde to aromatic hydrocarbon is in the range of 2.0 to 5.0, preferably 2.5 to 3.5. The sulfuric acid concentration is used in the range of 15 to 35% by weight as the concentration in the aqueous layer, preferably 20 to 30% by weight. The reaction temperature depends on whether an inert solvent is used or not, but it is usually carried out in the range of 80 to 110 ° C., preferably 9
5 to 105 ° C.

Examples of the aromatic hydrocarbon in the present invention include toluene, xylene, mesitylene, durene, naphthalene, and acenaphthylene, and as the formaldehyde, industrially easily available formalin, paraformaldehyde, and compounds that generate formaldehyde such as trioxane. can give.

〔The invention's effect〕

According to the method of the present invention, the content of the diallylmethane component is small, and -CH ₂ OH, -CH ₂ OCH ₃ , and -CH ₂ OC are attached to both ends of the molecule.
A compound having an end group such as H ₂ OCH ₃ and having active hydrogen, that is, an aromatic hydrocarbon formaldehyde resin rich in reactivity with phenols, carboxylic acids, or amines can be effectively produced. it can.

The aromatic hydrocarbon formaldehyde resin obtained by the present invention has excellent reactivity with a compound having active hydrogen, and a modified resin obtained by reacting with a compound having active hydrogen is a conventional aromatic hydrocarbon formaldehyde resin. A cured product having better mechanical and thermal properties than a resin-modified resin can be provided.

〔Example〕

 Examples of the present invention will be shown below.

In the examples, "%" and "parts" represent "% by weight" and "parts by weight" unless otherwise specified.

Example 1 In a separable flask of 2, equipped with a reflux condenser, a thermometer, and a 60 mm anchor-type stirrer, 47
% Formalin 691 parts (10.8 mol), 98% sulfuric acid 237 parts, metaxylene 572 parts (5.4 mol) were charged in this order, and the stirring speed was 200 rpm and the temperature was 98 ° C. under reflux.
The reaction was carried out at 103 ° C. for 7 hours, and the reaction was completed at a reaction rate of formaldehyde of 70 mol%. After that, 458 parts of diluting metaxylene was added to the product, and the mixture was stirred and allowed to stand to separate into an oil layer and an aqueous layer. The oil layer (that is, the resin layer) was washed twice with warm water and stripped under a reduced pressure of 130 ° C./30 mmHg for 1 hour to obtain 700 parts of a pale yellow viscous resin.

This resin is designated as A, and the analysis results are shown in Table 1.

Example 2 A reactor similar to that used in Example 1 was charged with 791 parts of 47% formalin (12.4 mol), 271 parts of 98% sulfuric acid,
Charged in the order of 438 parts (4.1 mol) of meta-xylene,
Agitation speed of 210 rpm, and 6 at 98 ° C to 103 ° C under reflux.
Reaction with formaldehyde for 65 hours
Then the reaction was completed. Then dilute meta-xylene 350
Part was added to the product, and the mixture was stirred and allowed to stand to separate into an oil layer and an aqueous layer. Wash the oil layer (ie resin layer) twice with warm water,
Stripping was carried out under reduced pressure of 30 ° C./30 mmHg for 1 hour to obtain 450 parts of a pale yellow viscous resin.

This resin was designated as B, and the analysis results are shown in Table 1.

Example 3 In a reactor similar to that used in Example 1, 47% formalin 739 parts (11.6 mol), 98% sulfuric acid 254 parts,
Meta-xylene 408 parts (3.9 mol) and n-octane 100 parts were charged in this order, reacted at a stirring speed of 200 rpm under reflux at a temperature of 98 ° C to 102 ° C for 6 hours, and reacted at a reaction rate of formaldehyde of 62 mol%. Finished.
Then, the mixture was allowed to stand and the oil layer and the water layer were separated. Oil layer with warm water 2
It was washed once and stripped under reduced pressure of 130 ° C./30 mmHg for 1 hour to obtain 430 parts of a pale yellow viscous resin.

This resin is designated as C. The analysis results are shown in Table 1.

Example 4 A reactor similar to that used in Example 1 was charged with 47% formalin.
853 parts (13.4 mol), 98% sulfuric acid 292 parts, metaxylene 284 parts (2.7 mol), n-heptane
71 parts were charged in this order, the mixture was reacted at a stirring rate of 250 rpm under reflux at a temperature of 96 ° C to 98 ° C for 5 hours, and the reaction was terminated at a reaction rate of formaldehyde of 53 mol%. Then, the mixture was allowed to stand and the oil layer and the water layer were separated. The oil layer was washed twice with warm water and stripped under reduced pressure of 130 ° C./30 mmHg for 1 hour to obtain 370 parts of a pale yellow viscous resin.

This resin is designated as D. The analysis results are shown in Table 1.

Example 5 47% formalin 2210 parts (347.6 mol), 98% sulfuric acid 7580 parts, and metaxylene 121 in a 50 glass-lined reaction kettle equipped with a reflux condenser, a thermometer, and a 300 mm anchor type stirrer.
90 parts (115 mol) and 3020 parts of n-heptane were charged in this order, and the stirring speed was 70 rpm, and the mixture was refluxed at 96 ° C to 98 ° C.
The reaction was carried out at a temperature of ℃ for 6 hours, and the reaction was completed at a reaction rate of formaldehyde of 66 mol%. Then, the mixture was cooled and allowed to stand still to separate an aqueous layer and an oil layer. Wash the oil layer twice with warm water, 1
Stripping was carried out at a reduced pressure of 30 ° C./30 mmHg for 1 hour to obtain 12800 parts of a pale yellow viscous resin.

Let this resin be E. The analysis results are shown in Table 1.

Comparative Example A reactor similar to that used in Example 1 was charged with 791 parts of 47% formalin (12.4 mol), 271 parts of 98% sulfuric acid,
Charged in the order of 438 parts (4.1 mol) of meta-xylene,
The mixture was reacted at a stirring rate of 800 rpm under reflux at a temperature of 98 ° C. to 103 ° C. for 4 hours to react the formaldehyde with a reaction rate of 85 mol%. Thereafter, the same treatment as in Example 1 was carried out to obtain 744 parts of a pale yellow viscous resin.

This resin was designated as F and the analysis results are shown in Table 1.

Example 6 A reactor similar to that used in Example 1 was charged with 47% formalin.
751 parts (11.8 mol), 98% sulfuric acid 188 parts, mesitylene 467 parts (3.9 mol), n.octane 1
It is charged in the order of 00 parts, and the mixture is refluxed at a stirring speed of 200 rpm for 9 minutes.
The reaction was carried out at a temperature of 8 to 103 ° C. for 6 hours, and the reaction was completed with a conversion of formaldehyde of 65%. Then, the mixture was allowed to stand and the oil layer and the water layer were separated. Wash the oil layer twice with warm water,
Stripping was carried out for 1 hour under reduced pressure of ° C / 30 mmHg to obtain 490 parts of a pale yellow viscous resin.

This resin is designated as G. The analysis results are shown in Table 1.

Example 7 In a reactor similar to that used in Example 1, 703 parts (11.0 mol) of 47% formalin, 240 parts of 98% sulfuric acid,
Naphthalene 467 parts (3.6 mol), n-octane
100 parts were charged in this order, and the mixture was reacted at a stirring rate of 200 rpm under reflux at a temperature of 98 to 103 ° C. for 6 hours, and the reaction was completed at a reaction rate of formaldehyde of 63%. Then, the mixture was allowed to stand and the oil layer and the water layer were separated. Wash the oil layer twice with warm water, 1
Stripping was carried out for 1 hour under a reduced pressure of 30 ° C./30 mmHg to obtain 480 parts of a pale yellow viscous resin. Let this resin be H. The analysis results are shown in Table 1.

It was quantified by gas chromatography using diallylmethane: methylenebenzoate as an internal standard substance.

Xylenol value: Aromatic hydrocarbon / formaldehyde resin is reacted with an equivalent amount or more of 2,6-xylenol under an acid catalyst, and unreacted 2,6-xylenol is quantified by gas chromatography using diphenylmethane as an internal standard substance. To do. Represented by the number of moles of 2,6-xylenol reacted per 1 kg of aromatic hydrocarbon / formaldehyde resin.

m = molecular weight of 2,6-xylenol W = weight of aromatic hydrocarbon / formaldehyde resin (g) X ₁ = weight of charged 2,6-xylenol (g) X ₂ = weight of residual 2,6-xylenol (g ) Molecular weight: Measured by VPO using methyl ethyl ketone as a solvent.

Terminal substituents per molecule -CH ₂ OH, -CH ₂ OCH ₃ , -CH ₂ OCH ₂ OC
Number of H ₃ : Measured by ¹ H-NMR using CDCl ₃ as a solvent.

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Claims (1)

[Claims] 1. When an aromatic hydrocarbon formaldehyde resin is produced by reacting formaldehyde with an aromatic hydrocarbon, the molar ratio of formaldehyde to aromatic hydrocarbon is 2.0 to 5.0, and the molar ratio of the formaldehyde to the aromatic hydrocarbon is 2.0 to 5.0. Sulfuric acid concentration 15 to 35
% By weight, while maintaining the interface between the water layer and the oil layer (resin layer) at a temperature of 80 to 110 ° C., it takes 4 to 8 hours to suppress the reaction rate of formaldehyde within the range of 50 to 70 mol%. Process for producing aromatic hydrocarbon formaldehyde resin characterized by reacting