JPH0433803B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a substantially linear high molecular weight novolac-type substituted phenolic resin quickly and in high yield through easy reaction operations. More specifically, by blending with various curable resins, resin compositions with excellent heat resistance and mechanical properties can be obtained, and high molecular weight novolac-type substituted phenolic resins can be used for various purposes. The present invention provides a method suitable for production. In the past, many researchers have made various attempts to produce high-molecular-weight novolac-type phenolic resins. Publication No. 1982-92908, Japanese Patent Publication No. 1983
−14615 Publication, JP-A-57-113, JP-A-57
-10644 Publication, JP-A-57-10645, JP-A-Sho
It was first produced by a method such as that disclosed in Japanese Patent No. 58-11551. However, the methods proposed in these publications all involve increasing the molecular weight of a low molecular weight novolac type or resol type substituted phenol resin, which is mainly composed of difunctional phenols, by reacting it with a chain extender. However, all of these methods have the advantage of being able to produce substantially linear, high molecular weight novolac-type substituted phenolic resins in high yields, but they require a two-step reaction process and are complicated to operate. Therefore, it could not be said that it is necessarily suitable for manufacturing on an industrial scale. Subsequently, methods for producing high molecular weight novolac-type substituted phenolic resins containing difunctional phenols as main components were disclosed in JP-A-56-103215, JP-A-57-80417, and JP-A-57-80417. Publication No. 187311,
JP-A-57-205417 and JP-A-58-32622
It has been proposed in the Publication No. Among these methods, the method proposed in JP-A-56-103215 uses a mixture of bifunctional phenols, paraformaldehyde, phosphoric acid, and a solvent, as is clear from the description of the examples. under reflux conditions
The reaction was carried out for 10 hours while raising the temperature from 100℃ to 200℃, and then for 2 hours while increasing the temperature to 260℃.
Since it is produced by dehydration condensation over a period of time, it has the disadvantage that the operation is multi-step and complicated, and moreover, a high molecular weight resin cannot be obtained.
Among these methods, another method proposed in the above-mentioned publication involves performing a first condensation reaction of bifunctional phenols and a large excess of formaldehyde in the presence of a solvent and an acidic catalyst, and then After the dehydration operation, the second condensation reaction takes a very long time. For example, if we look at this second condensation reaction, as is clear from the examples in all of the above-mentioned publications, this second condensation reaction takes 12 hours at the shortest time; It takes a long time, several tens of hours, and the operation is extremely complicated, as is clear from the examples in both Japanese Patent Application Laid-Open Nos. 57-80417 and 187311-1987. It has the following drawbacks. The present inventors recognized that the technology for producing a substantially linear high molecular weight novolac-type substituted phenolic resin exists in the above-mentioned situation, and realized that it is a one-step condensation reaction, a simple reaction operation, and a rapid process. We investigated a method for producing high-yield high-molecular-weight novolac-type substituted phenolic resins in the above line, and found that a condensation reaction between phenols, mainly composed of difunctional phenols, and aldehydes could be carried out under specific conditions. We found that the above purpose can be achieved by
We have arrived at the present invention. According to the method of the present invention, a high molecular weight novolak-type substituted phenolic resin can be obtained quickly and in high yield through a simple one-step condensation reaction operation, and is therefore suitable as an industrial production method. To summarize the present invention, in the present invention, a novolak-type substituted phenolic resin is produced by condensing a phenol containing difunctional phenols as a main component with an aldehyde in a solvent in the presence of an acidic catalyst. In the method, [a] the difunctional phenol in the phenols is
A phenol having two active hydrogens for substitution reaction on the benzene nucleus, which has the general formula (In the formula, two of the three R ¹ are hydrogen atoms, and the remaining one represents an alkyl group, an aryl group, a halogen atom, or a hydroxyl group, and R is a hydrogen atom, an alkyl group, a halogen atom, or hydroxyl group, and R ¹ and R each represent the same or different groups.) [b] The content of the bifunctional phenol component is 70
mol% or more, and the content of trifunctional phenols is in the range of 30 mol% or less, [c] the molar ratio of aldehyde to the phenols is in the range of 1.3 to 2.0, [d] The proportion of the acidic catalyst used is in the range of 3 to 15 mol% based on the phenols; [e] The solvent is an aromatic hydrocarbon, a halogenated aromatic hydrocarbon, a nitrated aromatic hydrocarbon, or an aromatic at least one kind selected from the group consisting of group ethers, and the proportion used is in the range of 80 to 500 parts by weight per 100 parts by weight of the phenols;
and [f] Invention of a process for producing a substantially linear high molecular weight novolac-type substituted phenolic resin having a number average molecular weight in the range of 1500 or more and characterized in that the temperature during the reaction is in the range of 160 to 250°C. This is the gist of the report. The phenols used in the method of the present invention are mainly composed of the above-mentioned specific difunctional phenols, and more specifically, the content of the difunctional phenols is in the range of 70 mol% or more. In addition, the content of trifunctional phenols must be in the range of 30 mol% or less, and furthermore, the content of difunctional phenols is preferably 80 mol% or more, particularly preferably 90 mol% or more. and preferably 20 mol% or less of trifunctional phenols,
Particularly preferred are phenols contained in a range of 10 mol% or less. Here, the total of both is 100
It is mole%. When the content of difunctional phenols in the raw material phenols decreases below 70 mol%,
A gel-like polymer is produced, and a substantially linear high molecular weight novolak-type substituted phenolic resin cannot be obtained. Further, the difunctional phenols used in the method of the present invention are phenols having two active hydrogens for substitution reaction on the benzene nucleus, and usually have the general formula [] (In the formula, two of the three R ¹ are hydrogen atoms, and the remaining one represents an alkyl group, an aryl group, a halogen atom, or a hydroxyl group, and R is a hydrogen atom,
Indicates an alkyl group, halogen atom or hydroxyl group,
R ¹ and R each represent the same or different groups. ) is a phenol expressed by
More specifically, the following ortho isomers or para isomers of phenols can be exemplified. For example, cresol, ethylphenol,
Alkylphenols such as n-propylphenol, isopropylphenol, n-butylphenol, sec-butylphenol, tert-butylphenol, sec-amylphenol, tert-aluminumphenol, hexylphenol, octylphenol; fluorophenol, chlorophenol, bromo Examples include ortho isomers or para isomers of phenols such as halophenols such as phenol, arylphenols such as phenylphenol and tolylphenol, and further 2,3-xylenol, 3,4-xylenol, 2, 5-xylenol, 2,3-diethylphenol, 3,4-diethylphenol, 2,5
-diethylphenol, 2,3-diisopropylphenol, 3,4-diisopropylphenol, 2,5-diisopropylphenol, 2,3
-dichlorophenol, 3,4-dichlorophenol, 2,5-dichlorophenol, 2,5-dichlorophenol, 2-methyl-3-phenylphenol, 3-methyl-4-phenylphenol, 2-methyl-5 -Phenylphenol can be exemplified. In addition, trifunctional phenols are phenols that have three active hydrogens on the benzene nucleus for substitution reactions, and specifically, they are phenols, meta-substituted phenols, or 3,5-substituted phenols. be. These trifunctional phenols usually have the general formula [] (In the formula, R is a hydrogen atom, an alkyl group, a halogen, or a hydroxyl group, and represents the same or different groups.)
These are phenols represented by More specifically, phenol, m-cresol, m-ethylphenol, m-propylphenol, m-isopropylphenol, m-butylphenol, m-
-amylphenol, m-hexylphenol,
Meta-substituted phenols such as m-heptylphenol, m-octylphenol, m-fluorophenol, m-chlorophenol, m-promophenol, resorcinol, 3,5-xylenol,
3,5-diethylphenol, 3,5-diisopropylphenol, 3,5-dibutylphenol, 3,5-diamylphenol, 3,5-dihexylphenol, 3,5-dioctylphenol, 3,5-difluorophenol , 3,5-disubstituted phenols such as 3,5-dichlorophenol and 3,5-dibromophenol. The aldehyde used in the method of the present invention is usually an aldehyde represented by the general formula [] R ² -CHO [] (wherein R ² represents a hydrogen atom, a methyl group or a halogenated methyl group), and Specifically, formaldehyde, acetaldehyde, monochloroacetaldehyde,
Examples include dichloroacetaldehyde and trichloroacetaldehyde. The molar ratio of the aldehyde to the phenols must be in the range of 1.3 to 2.0, preferably in the range of 1.4 to 1.8, particularly preferably in the range of 1.5 to 1.7. If the molar ratio of aldehyde to the phenols is less than 1.3, it will not be possible to obtain a high molecular weight, and if it is larger than 2.0, it will be difficult to obtain a high-quality polymer and the amount lost will increase, making it uneconomical. become inferior. Specifically, the acidic catalyst used in the method of the present invention includes inorganic protonic acids such as nitric acid, sulfuric acid, hydrochloric acid, perchloric acid, and phosphoric acid, and organic protonic acids such as toluenesulfonic acid, methanesulfonic acid, oxalic acid, and maleic acid. Examples include acids, boron trifluoride, various complexes of boron trifluoride such as boron trifluoride ether complexes, Lewis acids such as aluminum trichloride, tin tetrachloride, zinc chloride, ferric chloride, and titanium tetrachloride. be able to. Among these acidic catalysts, it is preferable to use protonic acids. The ratio of the acidic catalyst used is 3 to 3 to the phenols.
It is necessary that the content be in the range of 15 mol%, and more preferably in the range of 5 to 10 mol%. If the proportion of the acidic catalyst used is less than 3 mol %, a high molecular weight novolac-type substituted phenol resin cannot be obtained in high yield, and if it exceeds 15 mol %, the resulting resin will gel and become insolubilized. In the method of the invention the condensation reaction is carried out in a solvent. As the solvent, at least one selected from the group consisting of aromatic hydrocarbons, halogenated aromatic hydrocarbons, nitrated aromatic hydrocarbons, and aromatic ethers is used. Specifically, the solvents include benzene, toluene,
Aromatic hydrocarbons such as xylene, cumene, cymene, diisopropylbenzene, decalin, halogenated aromatic hydrocarbons such as chlorobenzene, bromobenzene, dichlorobenzene, nitrobenzene,
Examples include nitrated aromatic hydrocarbons such as chloronitrobenzene, aromatic ethers such as diphenyl ether, and the like. The proportion of the solvent used is 80 to 500 parts by weight per 100 parts by weight of the phenols.
It must be within the range of parts by weight, and
Preferably it is in the range of 100 to 300 parts by weight. If the proportion of the solvent used is less than 80 parts by weight, it will be difficult to obtain a high molecular weight product and the resulting resin will solidify, making post-treatment difficult; if it is greater than 500 parts by weight, the reaction will proceed slowly and it will be difficult to obtain a high molecular weight. . In the method of the present invention, the condensation reaction between phenols and aldehydes is carried out in the aforementioned solvent under heating. The temperature during the reaction must be in the range of 160 to 250℃, and more preferably 160 to 200℃.
The pressure during the condensation reaction is usually in the range of 1 to 20 kg/cm ² -G, preferably 5 to 15 kg/cm ² -G, and the time required for the reaction is usually 2 to 10 hours. , preferably 4 to 8
It is a range of time. If the reaction temperature is lower than 160°C, a high molecular weight novolak-type substituted phenolic resin cannot be obtained, and if it is higher than 250°C, a part of the resulting resin tends to gel and become insolubilized.
Water is produced during the condensation reaction, but the reaction can be carried out without removing the produced water, or the reaction can be carried out while the water produced during the reaction is removed from the reaction system by means such as azeotropy. You can also. In the method of the present invention, the condensation reaction is carried out by heating and stirring a mixture of phenols, aldehydes, acidic catalysts and solvents under the aforementioned conditions. A high molecular weight novolac-type substituted phenol resin can be obtained by pouring the reaction mixture after the condensation reaction into a poor solvent such as methanol, acetone, or water to cause precipitation, or by distilling off the solvent under heating. The high molecular weight novolac-type substituted phenolic resin obtained by the method of the present invention has a number average molecular weight (n) of usually 1500 or more, preferably 1700 or more, as measured by vapor pressure osmometry in N,N-dimethylacetamide solvent. 15,000 to 15,000, particularly preferably 2,000 to 10,000, and the molecular weight distribution (w/n) expressed as the ratio of weight average molecular weight to number average molecular weight is usually 1.8 to 20, preferably 2 to 10. The molecular weight fraction expressed as the content of resin components having a number average molecular weight of 2000 or more is usually 50% by weight or more, preferably 60% by weight or more, and particularly preferably 70% by weight or more.
Furthermore, the high molecular weight novolac-type substituted phenolic resin obtained by the method of the present invention is substantially linear, and here, substantially linear refers to a linear structure in which the resin chain is linear or branched. This means that it does not substantially contain a network structure (that is, a gel-like crosslinked structure). This can be confirmed by the fact that the high molecular weight novolak type substituted phenolic resin completely dissolves in N,N-dimethylacetamide at 23°C. Furthermore, the melting point of the high molecular weight novolac-type substituted phenol resin obtained by the method of the present invention is usually in the range of 120°C or higher, preferably 150°C or higher, and when measured by X-ray diffraction, it has a crystalline or amorphous structure. have. Next, the method of the present invention will be specifically explained using examples. Example 1 65 g (0.6 mol) of p-cresol, 73 g (0.9 mol) of 37% formalin, 3.5 g (0.03 mol) of maleic acid
mol) and 114 g of toluene were placed in a 500 ml autoclave and reacted at 175°C for 4 hours. Next, the reaction solution was poured into 600 ml of methanol to precipitate the product, which was washed with methanol, filtered, and dried to obtain 67 g of resin (yield: 92%). The number average molecular weight n of this resin measured by vapor pressure osmometry (in dimethylacetamide, 90°C) is 2000,
The molecular weight distribution (w/n) of this resin measured by gel permeation chromatography is
It was 2.35. Examples 2 to 3, Comparative Example 1 The same procedure as in Example 1 was conducted except that 37% formalin was used as shown in Table 1. The results are shown in Table 1.

[Table] Examples 4 to 5, Comparative Example 2 p-cresol and m-cresol were used as shown in Table 2, and 73 g of 37% formalin was added.
(0.9 mol of HCHO), 3.1 g (0.03 mol) of 61% nitric acid, and 131 ml of toluene in an autoclave,
The reaction was carried out at ℃ for 6 hours. Next, the same procedure as in Example 1 was carried out to obtain the results shown in Table 2.

[Table] Examples 6 to 8 In Example 1, p-cresol was replaced with o
-cresol, p-tert-butylphenol, p
- The same procedure as in Example 1 was carried out except that chlorophenol was used as shown in Table 3. The results are shown in Table 3.

[Table] Examples 9 to 12, Comparative Example 3 In Example 1, nitric acid, instead of maleic acid,
The same procedure as in Example 1 was conducted except that sulfuric acid and p-toluenesulfonic acid were used as shown in Table 4. The results are shown in Table 4.

[Table] Examples 13 to 15, Comparative Examples 4 to 5 Example 1 except that 3.1 g (0.03 mol) of 61% nitric acid was used instead of maleic acid, and the reaction temperature and time were as shown in Table 5. was carried out in the same manner as in Example 1. The results are shown in Table 5.

[Table] Examples 16 to 18, Comparative Example 6 The same procedure as in Example 1 was conducted except that o-dichlorobenzene, diphenyl ether, nitrobenzene, and dimethylacetamide were used instead of toluene. The results are shown in Table 6.

【table】

Claims (1)

[Claims] 1. A method for producing a novolac-type substituted phenolic resin by condensing a phenol containing difunctional phenols as a main component with an aldehyde in a solvent in the presence of an acidic catalyst, [ a] The difunctional phenol in the phenols is
A phenol having two active hydrogens for substitution reaction on the benzene nucleus, which has the general formula (In the formula, two of the three R ¹ are hydrogen atoms, and the remaining one represents an alkyl group, an aryl group, a halogen atom, or a hydroxyl group, and R is a hydrogen atom, an alkyl group, a halogen atom, or (represents a hydroxyl group, and R ¹ and R each represent the same or different groups), and [b] the content of the bifunctional phenol component is 70
mol% or more, and the content of trifunctional phenols is in the range of 30 mol% or less, [c] the molar ratio of aldehyde to the phenols is in the range of 1.3 to 2.0, [d] The proportion of the acidic catalyst used is in the range of 3 to 15 mol% based on the phenols; [e] The solvent is an aromatic hydrocarbon, a halogenated aromatic hydrocarbon, a nitrated aromatic hydrocarbon, or an aromatic at least one kind selected from the group consisting of group ethers, and the proportion used is in the range of 80 to 500 parts by weight per 100 parts by weight of the phenols;
and [f] a process for producing a substantially linear high molecular weight novolac-type substituted phenolic resin having a number average molecular weight in the range of 1500 or more and characterized in that the temperature during the reaction is in the range of 160 to 250°C.