JPS644526B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing resorcinol-formaldehyde resin. Resorcinol/formaldehyde resin is a resin-like material with a molecular weight distribution in which the predominant amount is dinuclear to pentanuclear, obtained by the condensation reaction of resorcinol and formaldehyde. Taking advantage of its characteristics such as thermosetting properties and rapid chemical reactivity, it has been used alone or in combination with other compounds as an adhesive for various materials. For example, Tokuko Sho 47-7640, Tokuko Sho 52
-26275 is a resin obtained by reacting resorcin and formaldehyde at a molar ratio of 1:0.5 to 0.9.
It is known that adhesion to fibers is improved by kneading it into rubber before vulcanization. However, when using these resins, it has been pointed out that unreacted resorcin monomers present in the resin cause blooming on the rubber surface, and contamination of the working environment and equipment due to evaporation of the resorcin monomers during rubber kneading. In order to solve these problems, it is conceivable to increase the amount of formaldehyde used relative to resorcin during the reaction in order to reduce unreacted resorcin monomers in the condensate. However, with this method, the molecular weight distribution of the resulting condensate shifts toward the polymer side, which increases the softening point of the resin, making it difficult to uniformly disperse it in the rubber at the temperature during rubber kneading. In extreme cases, a gel component that loses the thermofusible properties of the resin may be allowed to exist. Generally, resorcinol and formaldehyde react rapidly regardless of the presence or absence of a catalyst, but the content of unreacted resorcinol monomers in the resulting resin and the molecular weight distribution of the condensate can be determined by determining the reaction conditions. Even if the catalyst is changed, there is no significant difference in the results obtained. In other words, when the amount of formaldehyde is increased to reduce unreacted resorcinol, the molecular weight distribution of the resulting condensate shifts to the polymer side, while if one tries to keep the molecular weight distribution of the condensate within a certain range, This inevitably leads to an increase in unreacted resorcin. As described above, in the reaction of resorcin and formaldehyde, it is difficult to simultaneously control the content of resorcin monomer in the resulting resin and the molecular weight distribution of the condensate. The present inventors have completed the present invention as a result of intensive studies on a method for reducing the content of unreacted resorcin in the resin without affecting the molecular weight distribution of the condensate in the condensation reaction between resorcin and formaldehydes. . That is, the present invention provides a method for producing a resorcin-formaldehyde resin by a condensation reaction of resorcin and formaldehydes, in which resorcin is dissolved before, during or after the condensation reaction, and the dinuclear product obtained by the condensation reaction is A solvent that does not substantially dissolve components having a molecular weight of at least 10% is added to the reaction system in the presence or absence of water to treat the condensation reaction product obtained by the condensation reaction, and then the resin layer is removed from the solvent layer. The present invention provides a method for producing a resorcinol-formaldehyde resin characterized by separation. The details of the method of the present invention will be explained below. Formaldehyde used in the method of the present invention means formaldehyde and a compound capable of supplying formaldehyde into the system, or a compound having the same effect as supplying formaldehyde. Specific examples include formalin, paraform, trioxane, and formit. The conditions that the solvent used in the present invention should satisfy are as follows:
It is to dissolve resorcin and not to substantially dissolve components having a molecular weight of binuclear or higher obtained by the condensation reaction of resorcin and formaldehyde. More specifically, the solubility in resorcin is about 0.01 to 5% by weight at room temperature, 1% by weight or more, preferably 5% by weight or more in the temperature range where the operation is performed, and The solubility in components having a molecular weight is 0.5% by weight or less, preferably 0.1% by weight or less. Examples of solvents that meet these conditions include one or more selected from aromatic hydrocarbons, halogenated hydrocarbons, and ethers. More specifically,
Aromatic hydrocarbons include benzene, toluene,
Ortho-xylene, meta-xylene, para-xylene,
Mixed xylene, ethylbenzene, n-propylbenzene, isopropylbenzene, orthocymene,
Examples include metacymene, paracymene, chlorobenzene, orthodichlorobenzene, paradichlorobenzene, metadichlorobenzene, naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, 1-chlornaphthalene, and 2-chlornaphthalene. In addition, examples of halogenated hydrocarbons include chloroform, 1,2-dichloroethane, 1,1,1
-An example is trichloroethane. Examples of ethers include n-propyl-n-butyl ether, di-n-butyl ether, di-n-amyl ether, anisole, and phenethole. In order to carry out the method of the present invention most effectively, the water content in the condensation reaction product is adjusted by the type of solvent used. That is, the moisture content is 0 to 5% in the case of aromatic hydrocarbons, 0 to 15% in the case of halogenated hydrocarbons, and 10 to 30% in the case of ethers.
is preferred. The amount of solvent used in the method of the present invention can be determined as appropriate depending on the type of solvent, the water content in the condensation reaction product, the treatment temperature of the condensation reaction product, or the degree of reduction of the unreacted resorcin content. It is not particularly limited. Unfortunately, when reducing the content of unreacted resorcin by about 8%, the amount of solvent used is 1 to 8 times the weight of the condensation reaction product. When treating a condensation reaction product of resorcinol and formaldehyde, the solvent may be added to the reaction system before, during or after the condensation reaction, and the treatment temperature also depends on the molar ratio of resorcinol and formaldehyde, and the amount used. It can be appropriately selected depending on the type of solvent to be used, the fluidity of the condensation reaction product, the water content in the condensation reaction product, etc. Generally, the treatment temperature can be determined depending on the water content in the condensation reaction product and the type of solvent used,
For example, if the moisture content is 0-2%, it will be 100-110℃.
Above, in the case of 4 to 7%, the temperature is 50 to 60 °C or higher, and in the case of 10% or more, the temperature is above room temperature (approximately 20 °C) and below the boiling point of the solvent, or if water is present, the temperature is at the same temperature as the solvent and water. It is appropriately selected from the range below the boiling point. As described above, the method of the present invention prevents the blooming phenomenon on the rubber surface due to unreacted resorcin monomer,
A resorcinol/formaldehyde resin can be obtained that causes extremely little contamination of the working environment and equipment due to transpiration of resorcinol monomers during rubber kneading. The method of the present invention will be explained in detail below with reference to Examples, but the present invention is not limited to these Examples. Comparative Example 1 110g (1.0 mol) of resorcin in 50g of water at 100℃
48.6 g (0.6 mol) of 37% formalin was injected over 3 hours at this temperature while stirring.
After completion, it was stirred at this temperature for 10 hours and then heated under reduced pressure (20 mm
Hg), concentrating water at an internal temperature of 150℃ or less. Resin No.
117.4 g of A was obtained. Comparative Example 2 110 g (1.0 mol) of resorcin and 0.2 g of p-toluenesulfonic acid monohydrate were dissolved in 50 g of water by heating at 35 to 40°C, and at this temperature 37% formalin 48.6%
g (0.6 mol) over 3 hours. After the completion of the stirring, stirring was continued at this temperature for 15 hours, and after cooling, the mixture was neutralized to pH 4 to 4.5 with 0.1 g of 25% aqueous ammonia, and concentrated under the conditions of Comparative Example 1. 117.4 g of resin No. B was obtained. Comparative Example 3 110 g (1.0 mol) of resorcin and 0.2 g of p-toluenesulfonic acid monohydrate were dissolved in 50 g of water at 35-40°C, and at this temperature 48.6 g of 37% formalin was dissolved.
(0.6) mol is injected over 3 hours. After completion, the temperature was raised to 95-100°C, stirring was continued at this temperature for 6 hours, and after neutralization, the same treatment as in Comparative Example 2 was carried out. 117.5 g of resin No. C was obtained. Comparative Example 4 The conditions of Comparative Example 3 and the amount of 37% formalin were changed to 56.8
118.7 g of resin No. D was obtained by carrying out the same treatment except that the amount was changed to 0.7 mol. Comparative Example 5 The conditions of Comparative Example 3 and the amount of 37% formalin were changed to 64.9
The same process was performed except that the amount was changed to g (0.8 mol). Resin No.E120.0g was obtained. Comparative Example 6 The conditions of Comparative Example 3 and the amount of 37% formalin were changed to 40.5 g.
(0.5 mol) was treated in exactly the same manner, to obtain 116.3 g of resin No. F. Comparative Example 7 110g (1.0mol) of resorcin and 2g of caustic soda
(0.05 mol) in 120 g of water and adjust the temperature to 5-10℃.
Cool to 48.6 g of 37% formalin at this temperature.
(0.6 mol) is injected over 3 hours. After the completion of stirring at this temperature for 12 hours, p-toluenesulfonic acid 1
Add 9.8g of hydrate to adjust the pH to 1.3 and lower the temperature to 100.
C. and then stirred at this temperature for 6 hours. After cooling, PH4-4.5 with 0.1g of 25% ammonia water
The water was concentrated under the conditions of Comparative Example 1. Resin No.
- Obtained 119.3g of G. Comparative Example 8 110 g (1.0 mol) of resorcinol and 0.2 g of p-toluenesulfonic acid monohydrate are dissolved in 50 g of water at 60 to 70°C. At this temperature, 20.5 g (0.6 mol) of 88% paraformaldehyde was added over 3 hours.
After finishing, the temperature was raised to 100℃ and heated for 4 hours.
After cooling, the mixture is neutralized to pH 4 to 4.5 with 0.1 g of 25% aqueous ammonia, and water is concentrated under the conditions of Comparative Example 1. Resin No.-
117.3 g of H was obtained. Table 1 shows the resorcin monomer content and molecular weight distribution of Comparative Example Resins No. A to H.

[Table] Example 1 The reaction between resorcin and formalin was carried out in the same manner as in Comparative Example 3. i.e. 110g of resorcinol
(1.0 mol) and p-toluenesulfonic acid monohydrate
0.2g is dissolved in 50g of water at 35-40°C, and at this temperature 48.6g (0.6 mol) of 37% formalin is injected over 3 hours. After finishing, raise the temperature to 95-100℃, continue stirring at this temperature for 6 hours, and after cooling, 25%
Neutralize to PH4-4.5 with 0.1g of ammonia water. This aqueous solution is concentrated under reduced pressure (20 mmHg) at an internal temperature of 150° C. or less, and the concentration is terminated when the water content in the remaining resin becomes 1% or less. Mixed xylene in the system
Charge 500 g, stir at 125-140°C for 10 minutes, leave to stand at this temperature, and remove the supernatant xylene layer. Concentrate the remaining small amount of xylene under reduced pressure (20 mmHg) and below 150°C. 107.2 g of Resin No.-1 was obtained. Example 2 The same procedure as in Example 1 was carried out except that the mixed xylene was changed to ethylbenzene. Resin No.-2 107.6 was obtained. Example 3 In exactly the same manner as in Example 1, mixed xylene 500
g was changed to 800 g of toluene, and after the addition of toluene, stirring was performed at 110 to 113° C. for 20 minutes. Resin No.-3 107.3 was obtained. Example 4 After carrying out the reaction and neutralization in exactly the same manner as in Example 1, the water was concentrated under reduced pressure (20 mmHg) at 150°C or lower, and the concentration was finished when the remaining water in the resin reached 7%. do. Charge 600 g of 1,2-dichlorothane, stir at 70-75°C for 10 minutes, leave to stand at this temperature, and remove the lower resin layer into a separate container. The obtained resin layer is concentrated in the same manner as in Example 1 to remove a small amount of remaining 1,2-dichloroethane and water. Resin No.
-4 108.1g was obtained. Example 5 In exactly the same manner as in Example 4, the concentration was terminated when the water content in the remaining resin reached 17%. G-n
- Add 370 g of butyl ether, stir at 85-90°C for 10 minutes, let stand at this temperature, and remove the lower resin layer into a separate container. A small amount of gel is extracted from the resin liquid obtained.
n-Butyl ether and water are removed in the same manner as in Example 1. 106.3 g of resin No.-5 was obtained. Example 6 In exactly the same manner as in Example 4, the concentration was terminated when the water content in the remaining resin reached 22%. Add 390g of anisole and stir at 85-90℃ for 10 minutes.
Thereafter, treatment was carried out in the same manner as in Example 5, and resin No.-6
108.3g was obtained. Example 7 In exactly the same manner as in Example 1, mixed xylene,
Instead of using 500g, use 750g of mixed xylene. 105.2 g of resin No.-7 was obtained. Example 8 In exactly the same manner as in Example 1, the concentration was terminated when the water content in the remaining resin reached 3%. 900 g of mixed xylene was charged and the following treatment was carried out in the same manner as in Example 1. 108.2 g of resin No.-8 was obtained. Example 9 Before starting the reaction under the same conditions as in Example 1, 370 g of di-n-butyl ether was allowed to coexist in the system. After formalin injection, 85~
Heat at 90℃ for 10 hours, add 0.1g of 25% ammonia water,
Neutralize the aqueous layer to pH 4-4.5. Water is removed from the system by utilizing the azeotropy of di-n-butyl ether and water, and when the remaining water in the resin reaches the same amount as in Example 5, the dehydration is completed. After standing still, the resin liquid in the lower layer is taken out into a separate container, and a small amount of solvent and moisture are removed therefrom in the same manner as in Example 1. 107.8 g of resin No.-9 was obtained. Example 10 The reaction of resorcin and formalin was carried out in exactly the same manner as in Example 1, except that the reaction was carried out under the conditions of Comparative Example 1. 106.9 g of resin No.-10 was obtained. Example 11 The reaction of resorcinol and paraformaldehyde was
It was carried out under the conditions of Comparative Example 7, and after the neutralization treatment, it was carried out in exactly the same manner as in Example 1. 107.7 g of resin No.-11 was obtained. Example 12 A reaction was carried out under the conditions shown in Comparative Example 6, and the same procedure as in Example 1 was carried out after the neutralization treatment. resin
No.-12 108.5g was obtained. Table 2 shows the resorcin monomer content and molecular weight distribution of resins No. 1 to No. 12 in the above examples.

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Claims (1)

[Scope of Claims] 1. In a method for producing a resorcinol-formaldehyde resin by a condensation reaction between resorcinol and formaldehydes, resorcinol is dissolved before, during or after the condensation reaction, and the two nuclei obtained by the condensation reaction are dissolved. At least one solvent selected from aromatic hydrocarbons, halogenated hydrocarbons, and ethers is added to the reaction system in the presence or absence of water, and is a solvent that does not substantially dissolve components having a molecular weight greater than that of the organic compound. 1. A method for producing a resorcinol-formaldehyde resin, which comprises adding the condensation reaction product obtained by the condensation reaction, and then separating the resin layer from the solvent layer. 2 The solvent is benzene, toluene, orthoxylene, metaxylene, paraxylene, mixed xylene, ethylbenzene, n-propylbenzene, isopropylbenzene, orthocymene, metacymene, paracymene, chlorobenzene, orthodichlorobenzene, paradichlorobenzene, metadichlor Benzene, naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, 1-chlornaphthalene, 2-chlornaphthalene, chloroform, 1,
2-dichloroethane, 1,1,1-trichloroethane, n-propyl-n-butyl ether, di-
n-butyl ether, di-n-amyl ether,
The method according to claim 1, wherein at least one selected from anisole and phenethole is used.