JP2008095114A - Resorcinol-formalin resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resorcinol-formalin resin containing no salt, having an appropriate flowability of water-based solution, and can decrease both a content of resorcinol monomer and a content of resorcinol-formalin resin of resorcinol pentanuclear or higher nuclear bodies in a one-stage reaction. <P>SOLUTION: The resorcinol-formalin resin comprises adding 20-150 pts.wt. resorcinol and 20-80 pts.wt. inorganic salt relative to 100 pts.wt. water, within a range of solubility to water, and 10-200 pts.wt. organic solvent having a solubility parameter of 7.0-12.5 and capable of dissolving the resorcinol-formalin resin to 100 pts.wt. resorcinol to give a two-phase system containing no remaining solid matter, adding an organic acid or an inorganic acid, adding and reacting 1-40% formalin dropwise into the reaction mixture in a molar ratio of formaldehyde/resorcinol of 0.3-0.8 while maintaining it at 0-60°C. After the reaction, removing the water layer, adding an organic solvent in an amount of 1-5 equivalents to the amount of an organic solvent layer, adding water in an amount which is a half of the amount of the organic solvent, stirring the mixture and then removing the water layer after allowing it to stand to manufacture the resorcinol-formalin resin. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a resorcin formalin resin in which the resorcin formalin resin content and the resorcin formalin resin content of resorcin pentanuclear or more are reduced by adjusting the molecular weight of the resorcin formalin resin, and a method for producing the resorcin formalin resin.

  Conventionally, resorcin formalin resin is used for adhesives, plywood, laminated materials, surface coatings, etc. because of its fast curing speed, and especially has excellent adhesion to rubber and fibers. (See, for example, Japanese Patent Publication No. 48-12185, Japanese Patent Laid-Open No. 4-148920, Japanese Patent Laid-Open No. 6-100850, and Japanese Patent Laid-Open No. 2000-178849).

  When the resorcin formalin resin is used as an adhesive, it is required that the resorcin formalin resin has sufficient fluidity and that it is uniformly dissolved when the solvent coexists. When paying attention to fluidity, it is empirically known that sufficient fluidity can be obtained by reducing the composition ratio of the resorcin pentanuclear or higher from the components of the polycondensate. When the resorcin pentanuclear or higher, the ratio of the three-dimensional structure suddenly increases, and it is considered that fluidity is lost. Although it is conceivable to dilute with an organic solvent in order to impart fluidity, the use of an organic solvent is not preferred because it has the possibility of deteriorating the working environment and reducing the adhesive strength. There is a method in which an adhesive is dispersed in water with an anionic surfactant without using an organic solvent (see, for example, JP-A-57-167342), but there is concern about the long-term stability of the aqueous dispersion. Is leaving.

  As described above, it is known that a sufficient fluidity can be obtained when the solvent is water by reducing the constituent ratio of the resorcin 5 nucleus or more from the constituents of the polycondensate. If the reaction conditions are set so as to reduce the composition ratio above the nucleus, the molecular weight distribution of the product is simply shifted to the low molecular weight side. Normally, unreacted resorcin (resorcin mononuclear) The concentration becomes high. When the resorcin concentration is high, resorcin is sublimated when the adhesive is used, so that the working environment may be deteriorated and the adhesive force may be lowered. When 0.6 mol of formaldehyde is reacted with 1 mol of resorcin, about 33 wt% of unreacted resorcin is contained after the reaction is completed, and when 0.8 mol of formaldehyde is reacted, about 20 wt% In order to reduce the unreacted resorcin content, sublimate resorcin at a reduced pressure of 0.05 mmHg and 130 ° C. to reduce the unreacted resorcin content. It has been reported that it has been removed (for example, see Japanese Examined Patent Publication No. 54-932). It has also been reported that the content of unreacted resorcin is reduced to 5.5% using methyl isobutyl ketone as a solvent and water as an extractant to reduce the unreacted resorcin content (for example, Japanese Patent Publication No. 49-14550). reference). However, these methods are disadvantageous industrially, such as requiring vacuum distillation after the completion of the reaction or requiring a long operation using a continuous extractor.

  Conversely, if the reaction conditions are made violent in order to reduce the concentration of unreacted resorcin, a large amount of resorcin polynuclear body having 5 or more nuclei is generated, which is not preferable. Here, since the reaction is carried out in an aqueous system, a method of adding a high-concentration salt after completion of the reaction to reduce the solubility of the high molecular weight component and removing it after precipitation can be considered. However, this method is disadvantageous because it requires the addition of a salting-out step, and there is a concern about the decrease in adhesive strength due to the inorganic salt remaining in the resorcin formalin resin and the corrosion of the adherend due to the inorganic salt. It has not been. There has been disclosed a device that does not add this salting-out step and does not increase the composition ratio of seven or more nuclei even in a one-stage reaction (see, for example, JP-A-2003-277308). In order to reduce the solubility of the resorcinol multinuclear body, a large amount of salt coexists in the reaction system. However, in this method, the resorcinol multinuclear body precipitated from the aqueous phase becomes gummy, so resorcin, resorcin 2 nuclei As a result, even the body and resorcin trinuclear body are incorporated into the gum-like substance, resulting in a decrease in the reaction rate and a longer reaction time. In industrial production, the production of a gum-like substance in a long-time reaction is difficult to employ because it causes stirring stoppage, clogging of the liquid feeding system, and the like.

  The object of the present invention is to contain both a resorcin monomer content and a resorcin formalin resin content greater than or equal to resorcin pentanuclear in a single-step reaction, having an appropriate fluidity when it is made into an aqueous solution without containing salt It is to provide a resorcin formalin resin and a method for producing the same.

  Resorcin formalin resin is water-soluble and soluble in some organic solvents, and its ability to dissolve is not biased to either water or organic solvents. It is difficult to connect to. However, in order to solve the above-mentioned problems, the present inventors have focused on the solubility characteristics (solubility parameters) of organic solvents, and as a result of earnestly examining the reaction between resorcin and formalin from various angles, it was found that organic solvents in a specific range were selected. By adopting a liquid-to-liquid heterogeneous reaction to be used, it was found that both the resorcin monomer content and the resorcin formalin resin content of the resorcin pentanuclear or higher can be simultaneously reduced, and the following invention is completed. It came.

[1]
(A) 20 to 150 parts by mass of resorcin (A) is added to 100 parts by mass of water in an aqueous solvent, and an inorganic salt (B) that dissolves 20 parts by mass or more with respect to 100 parts by mass of water is dissolved in water. 20 to 80 parts by mass with respect to 100 parts by mass of water, and an organic solvent (C) having a dissolution parameter of 7.0 to 12.5 for dissolving the resorcin formalin resin is added to 100 parts by mass of resorcin (A). 10 to 200 parts by mass, and stirred at a liquid temperature equal to or lower than the boiling point of the organic solvent (C) to form a two-phase system in which no solid content remains, and a catalytic amount of an organic acid or inorganic acid (D) is added, While maintaining the reaction system at 0 to 60 ° C., 1 to 40% formalin (E) is adjusted to formaldehyde / resorcin = 0.3 to 0.8 mol ratio with respect to resorcin (A). Dripping over a period of time Thereafter, the mixture is further stirred for 10 to 60 minutes to cause a heterogeneous reaction to proceed. (B) The reaction system is allowed to stand while maintaining the temperature at the time of the reaction and separated into two layers. The aqueous layer is removed and the organic solvent is removed. Add the organic solvent (C) to the reaction product layer, which is a layer, and dilute it by adding an amount equivalent to 5 times the amount of the reaction product, and add half the amount of water of the organic solvent to maintain the temperature below the boiling point. The reaction system is stirred while standing, separated into two layers, and the aqueous layer is removed to obtain a resorcin formalin resin, containing no inorganic salt, resorcin monomer and resorcin pentanuclear or more resorcin formalin A resorcin formalin resin produced by a production method in which all steps including one-step reaction and liquid-liquid distribution are performed in the same reactor with a reduced resin content.

[2]
The aforementioned 1 to 40% formalin (E) is intermittently added dropwise to resorcin (A) at a ratio of formaldehyde / resorcin = 0.3 to 0.8 mol over 20 to 300 minutes with stirring. The resorcin formalin resin according to [1], which is added.

[3]
The peak area corresponding to the resorcin pentanuclear or more obtained by gel permeation chromatography analysis of the resorcin formalin resin described above is 30% to 55% with respect to the entire peak area, and corresponds to the resorcin monomer. The resorcin formalin resin according to any one of [1] to [2], wherein the peak area is 3% to 9% with respect to the total peak area.

[4]
The resorcin formalin resin according to any one of [1] to [3], wherein the organic solvent (C) is an organic solvent having a solubility parameter of 9.0 to 11.0.

[5]
The resorcin formalin resin according to any one of [1] to [4], wherein the organic solvent (C) is an organic solvent (C) represented by the following general formula [1].
General formula [1]

[Wherein, m represents 0 or 1, and n represents 0 or 1. R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are each independently a methyl group, an ethyl group, an n-propyl group, a 2-propyl group, an n-butyl group, a secondary butyl group, an isobutyl group, or a tertiary butyl group. Represents. When m = n = 0, R ₁ and R ₂ may be combined to form a ring, and when m = 1 and n = 0, R ₂ and R ₃ may be combined to form a ring. Well, when m = n = 1, R ₃ and R ₄ may combine to form a ring. ]

[6]
The resorcin formalin resin according to any one of [1] to [5], wherein the organic solvent (C) is used as a mixture of two or more kinds.

[7]
To the resorcin formalin resin in the organic solvent (C) solution of the resorcin formalin resin in step (b) described above, 1 to 10 times the amount of water is added by weight, and the organic solvent (C) is removed by distillation. Finally, the resorcin formalin resin solution according to any one of [1] to [6], wherein an aqueous resorcin formalin resin solution having an appropriate fluidity with a reaction product concentration of 30 to 80% is obtained.

[8]
The organic solvent (C) was diluted by adding 2 to 10 times the weight of the reaction product to the organic solvent layer which was separated into two layers after removing the aqueous layer after standing in the step (b), and water and organic The resorcin formalin according to any one of [1] to [7], characterized in that it is dehydrated by distillation at the azeotropic temperature of the solvent, then cooled to room temperature and then filtered to remove solids. resin.

[9]
(A) 20 to 150 parts by mass of resorcin (A) is added to 100 parts by mass of water in an aqueous solvent, and an inorganic salt (B) that dissolves 20 parts by mass or more with respect to 100 parts by mass of water is dissolved in water. 20 to 80 parts by mass with respect to 100 parts by mass of water, and an organic solvent (C) having a dissolution parameter of 7.0 to 12.5 for dissolving the resorcin formalin resin is added to 100 parts by mass of resorcin (A). 10 to 200 parts by mass, and stirred at a liquid temperature equal to or lower than the boiling point of the organic solvent (C) to form a two-phase system in which no solid content remains, and a catalytic amount of an organic acid or inorganic acid (D) is added, While maintaining the reaction system at 0 to 60 ° C., 1 to 40% formalin (E) is adjusted to formaldehyde / resorcin = 0.3 to 0.8 mol ratio with respect to resorcin (A). Dripping over a period of time Thereafter, the mixture is further stirred for 10 to 60 minutes to cause a heterogeneous reaction to proceed. (B) The reaction system is allowed to stand while maintaining the temperature at the time of the reaction and separated into two layers. The aqueous layer is removed and the organic solvent is removed. Add the organic solvent (C) to the reaction product layer, which is a layer, and dilute it by adding an amount equivalent to 5 times the amount of the reaction product, and add half the amount of water of the organic solvent to maintain the temperature below the boiling point. The reaction system is stirred while standing, separated into two layers, and the aqueous layer is removed to obtain a resorcin formalin resin, which contains no inorganic salt, resorcin monomer and resorcin pentanuclear or higher resorcin formalin The resin content is reduced, the peak area corresponding to the resorcin pentanuclear or more is 30 to 55% with respect to the entire peak area, and the peak area corresponding to the resorcin monomer is relative to the entire peak area. 3 to 9% All steps wherein the is carried out in the same reactor, a manufacturing method of the resorcinol-formalin resin containing response and liquid-liquid distribution.

[10]
The aforementioned 1 to 40% formalin (E) is intermittently added dropwise over 20 to 300 minutes with stirring at a ratio of formaldehyde / resorcin = 0.3 to 0.8 mol with respect to resorcin (A). The method for producing a resorcin formalin resin according to [9], wherein the addition is performed.

[11]
The peak area corresponding to the resorcin pentanuclear or more obtained by gel permeation chromatography analysis of the resorcin formalin resin described above is 30% to 55% with respect to the entire peak area, and corresponds to the resorcin monomer. The method for producing a resorcin formalin resin according to any one of [9] to [10], wherein the peak area is 3% to 9% with respect to the total peak area.

[12]
The method for producing a resorcin formalin resin according to any one of [9] to [11], wherein the organic solvent (C) is an organic solvent having a solubility parameter of 9.0 to 11.0.

[13]
The above-mentioned organic solvent (C) is an organic solvent (C) represented by the following general formula [1]. Production of resorcin formalin resin according to any one of [9] to [12] Method.
General formula [1]

[Wherein, m represents 0 or 1, and n represents 0 or 1. R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are each independently a methyl group, an ethyl group, an n-propyl group, a 2-propyl group, an n-butyl group, a secondary butyl group, an isobutyl group, or a tertiary butyl group. Represents. When m = n = 0, R ₁ and R ₂ may be combined to form a ring, and when m = 1 and n = 0, R ₂ and R ₃ may be combined to form a ring. Well, when m = n = 1, R ₃ and R ₄ may combine to form a ring. ]

[14]
The method for producing a resorcin formalin resin according to any one of [9] to [13], wherein the organic solvent (C) is used as a mixture of two or more kinds.

[15]
One or two or more kinds of cations, wherein the inorganic salt (B) is selected from alkali metals and alkaline earth metals, sulfate ions, nitrate ions, chlorine ions, bromine ions, iodine ions or thiocyanate ions The method for producing a resorcin formalin resin according to any one of [9] to [14], wherein the salt is composed of one or more anions selected from

[16]
The method for producing a resorcin formalin resin according to any one of [9] to [15], wherein the inorganic salt (B) is calcium chloride.

[17]
Any of [9] to [16], wherein the amount of the organic solvent (C) added in the step (a) is 30 to 100 parts by mass with respect to 100 parts by mass of resorcin (A). A method for producing a resorcin formalin resin according to item 2.

[18]
The method for producing a resorcin formalin resin according to any one of [9] to [17], wherein the organic acid or inorganic acid (D) is hydrochloric acid.

[19]
[9] to [18], wherein the number of moles of formaldehyde in the formalin (E) is a ratio of formaldehyde / resorcin = 0.5 to 0.8 mol with respect to the number of moles of resorcin (A). A method for producing a resorcin formalin resin according to any one of the items.

[20]
The method for producing a resorcin formalin resin according to any one of [9] to [19], wherein the dropping time of the formalin (E) is 20 to 120 minutes.

[21]
To the resorcin formalin resin in the organic solvent (C) solution of the resorcin formalin resin in step (b) described above, 1 to 10 times the amount of water is added by weight, and the organic solvent (C) is removed by distillation. Finally, a resorcin formalin resin aqueous solution having a moderate fluidity with a reaction product concentration of 30 to 80% is obtained. The method for producing a resorcin formalin resin according to any one of [9] to [20] .

[22]
The organic solvent (C) was diluted by adding 2 to 10 times the weight of the reaction product to the organic solvent layer which was separated into two layers after removing the aqueous layer after standing in the step (b), and water and organic The resorcin formalin resin according to any one of [9] to [20], wherein the solvent is distilled at an azeotropic temperature of the solvent, dehydrated, then cooled to room temperature, and then solids are removed by filtration. Manufacturing method.

The production method of the resorcin formalin resin is characterized by adopting a liquid-liquid heterogeneous reaction. Advantages obtained by employing the liquid-liquid heterogeneous reaction are as follows.
(1) Since the reaction is faster in the aqueous phase and the resorcin abundance ratio depends on the aqueous phase, the amount of unreacted resorcin can be reduced.
(2) As the reaction proceeds, the solubility of the resorcinol polynuclear body (especially the four-nuclear body having a three-dimensional structure or more) in the aqueous phase suddenly decreases and shifts to the organic phase. Is slow, the production of resorcin polynuclear bodies with 5 or more nuclei is suppressed.
(3) Since the reaction proceeds in both the aqueous phase and the organic phase, the reaction time can be shortened.
(4) The reaction is completed in a one-step reaction between resorcin and formalin, and a process for removing the resorcin polynuclear body after the reaction is not required.
(5) For the above reasons, the production amount of both unreacted resorcin and resorcin polynuclear body can be reduced, the reaction time can be shortened, and furthermore, the reaction can be completed in one step, which is costly. Very advantageous.

  Examples of the cation of the inorganic salt (B) used in the method for producing the resorcin formalin resin include alkali metal lithium, sodium, potassium, rubidium, cesium, alkaline earth metal magnesium, calcium, strontium, and barium cation. Is mentioned. Examples of the anion of the inorganic salt (B) include sulfate ion, nitrate ion, chlorine ion, bromine ion, iodine ion and thiocyanate ion. Preferably, it is calcium chloride.

  The inorganic salt (B) described above can be used alone or in admixture of two or more. These inorganic salts are used in an amount of 20 to 80 parts by mass, preferably 30 to 50 parts by mass with respect to 100 parts by mass of water. In any case, these inorganic salts are used within the range of solubility in water.

The solubility parameters used in the process for producing the resorcin formalin resin are specifically described in “Solubility Parameters For Film Forms” (Official Digest, October, 1955).
The calculation formula calculated using the physical constant is as follows.
δ = {(ΔH−RH) / V} ^1/2
δ: solubility parameter ΔH: latent heat of vaporization R: gas constant V: molar volume An organic solvent having a solubility parameter of less than 7.0 has low solubility of the resorcin polynuclear substance, so that the resorcin multinuclear substance is precipitated as a solid and used in the above production method Can not. Moreover, since the organic solvent exceeding 12.5 is mixed well with water, it cannot be used since the liquid-liquid heterogeneous reaction which is one of the characteristics of the manufacturing method cannot be performed.

  An organic solvent having a solubility parameter of 9.0 to 11.0 is preferable as the organic solvent used in the production method because it dissolves the resorcin polynuclear substance and forms a liquid-liquid heterogeneous system with water.

What is preferable among the organic solvents (C) represented by the solubility parameter 7.0 to 12.5 is as represented by the general formula [1] in terms of the structural formula.
General formula [1]

[Wherein, m represents 0 or 1, and n represents 0 or 1. R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are each independently a methyl group, an ethyl group, an n-propyl group, a 2-propyl group, an n-butyl group, a secondary butyl group, an isobutyl group, or a tertiary butyl group. Represents. When m = n = 0, R ₁ and R ₂ may be combined to form a ring, and when m = 1 and n = 0, R ₂ and R ₃ may be combined to form a ring. Well, when m = n = 1, R ₃ and R ₄ may combine to form a ring. ]

  Specific examples of the organic solvent (C) having a solubility parameter of 7.0 to 12.5 used in the method for producing the resorcin formalin resin include methyl ethyl ketone, methyl isobutyl ketone, acetone, tetrahydrofuran, diisopropyl ether, dibutyl ether, and acetic acid n. -Butyl, dimethyl carbonate, diethyl carbonate, etc. are mentioned, Preferably, methyl ethyl ketone, acetone, tetrahydrofuran, dimethyl carbonate, diethyl carbonate etc. which are organic solvents (C) of the solubility parameter 9.0-11.0 are mentioned. More preferred is methyl ethyl ketone. Moreover, these organic solvents can also be used in mixture of 2 or more types. As the usage-amount, 10-200 mass parts is suitable with respect to 100 mass parts of resorcinol.

  Examples of the organic acid or inorganic acid (D) used as a catalyst in the method for producing the resorcin formalin resin include hydrochloric acid, sulfuric acid, phosphoric acid, benzenesulfonic acid, toluenesulfonic acid and the like. Preferably, it is hydrochloric acid.

  Moreover, to the organic solvent solution of the resorcin formalin resin after completely removing the inorganic salt, 1-10 times the amount of water is added and distilled with respect to the resorcin formalin resin, the organic solvent is removed, In the final step, the resorcin formalin resin of the present invention is used in the next step to obtain an aqueous solution of resorcin formalin resin having a moderate fluidity with a reaction product concentration of 30 to 80%, preferably 40 to 60%. It is an easy form. Moreover, although 1-10 times amount of water is added by weight with respect to resorcin formalin resin, the amount of water sufficient to finally make the residual amount of organic solvent 1 mass% or less by azeotropic distillation This means that it is possible to deviate from 1 to 10 times the amount. In the next step, the following method described in Japanese Patent Publication No. 48-12185 is adopted. The adhesive stock solution is preferably diluted with water before treating the fiber material or film. This is because when an appropriate amount of a basic substance is added to the dilution water, the adhesive is easily dissolved.

  Since the reaction tank used in the present invention performs an acid catalyst reaction, an ordinary apparatus can be used as long as it is acid-resistant. The reaction temperature employed in the present invention is preferably below the boiling point of the organic solvent used. Further, since it is necessary to dissolve the salt in water at a high concentration, it is necessary to make the temperature somewhat higher than room temperature in order to ensure solubility. The reaction temperature is 0 to 60 ° C., preferably 30 to 50 ° C.

  The organic solvent used in the present invention can be recovered and reused by being distilled again after being separated by distillation. The salt used in the present invention can be recovered after separation and reused.

  The formaldehyde concentration in formalin (E) used by this invention is 1-40 mass%, Preferably it is 30-40 mass%. Further, the amount of formalin used is such that the number of moles of formaldehyde in the formalin is in the ratio of formalin / resorcin = 0.3 to 0.8 mol, preferably in the ratio of formalin / resorcin = 0.5 to 0.8 mol with respect to resorcin. It is an amount.

Hereinafter, the present invention will be described in detail with reference to examples.
[Example 1]
After adding 133 kg of water, 85 kg of calcium chloride, and 111 kg of resorcin in an acid-resistant 500 liter reaction tank and dissolving them at 50 ° C., 45 kg of methyl ethyl ketone and 0.45 kg of 35% hydrochloric acid were placed in the reaction tank. While maintaining the reaction system at 50 ° C., 53 kg of 37% formalin was added dropwise over 30 minutes, and after completion of the addition, the mixture was further stirred for 30 minutes to promote a liquid-liquid heterogeneous reaction. While maintaining the temperature of the reaction system, the mixture was left to separate into two layers, and the lower aqueous phase was extracted. The organic phase is diluted with 200 kg of methyl ethyl ketone, 100 kg of water is added, and the reaction system is further stirred for 30 minutes while maintaining the same temperature. After standing, it is separated into two layers, the aqueous phase is extracted, and the methyl ethyl ketone of resorcin formalin resin is extracted. A solution was obtained.

  200 kg of water was added to the methyl ethyl ketone solution of the resorcin formalin resin obtained and distilled at an azeotropic temperature to remove the methyl ethyl ketone and reduce the water content. There was obtained 263 kg of an aqueous resorcin formalin resin solution. This resorcin formalin resin aqueous solution having a solid content of about 50% does not contain an inorganic salt, and is a resorcin formalin resin in which the content of resorcin formalin resin of resorcin monomer and resorcin pentanuclear is reduced.

  The obtained resorcin formalin resin was dissolved in tetrahydrofuran and subjected to gel permeation chromatography analysis to measure the distribution of unreacted resorcin to resorcin pentanuclear or higher. The obtained chromatogram is shown in FIG. The calculated peak area ratio is shown in Table 1.

The gel permeation chromatography analysis conditions are shown below.
Measurement model: Tosoh HLC-8020
Column: (G-2500) + (G-2500) + (G-4000)
Column temperature: 40 ° C
Solvent: Tetrahydrofuran Flow rate: 1 ml / min

[Example 2]
1536 g of water, 850 g of calcium chloride, 1107.0 g of resorcin, and 450 g of methyl ethyl ketone were placed in a 5 L glass Kolben, dissolved at 60 ° C., and then 4.5 g of 35% hydrochloric acid was placed in the reaction vessel. The reaction system was cooled to 50 ° C., while maintaining 50 ° C., 490 g of 37% formalin was added dropwise over 45 minutes, and after completion of the addition, the mixture was further stirred for 1 hour at 50 ° C. to promote a liquid-liquid heterogeneous reaction. Thereafter, 40 g of 37% formalin was added dropwise over 45 minutes, and after completion of the addition, the mixture was further stirred at 50 ° C. for 1 hour to promote a liquid-liquid heterogeneous reaction. The reaction system was allowed to stand while maintaining the same temperature to separate into two layers, and the lower aqueous phase was extracted. The organic phase is diluted with 1500 g of methyl ethyl ketone, 750 g of water is added, and the reaction system is further stirred for 1 hour while maintaining the same temperature. After standing, it is separated into two layers, the aqueous phase is taken out, and methyl ethyl ketone of resorcin formalin resin is obtained. A solution was obtained.

  To the resulting methyl ethyl ketone solution of resorcin formalin resin, 2000 g of water is added and distilled at an azeotropic temperature to remove methyl ethyl ketone and reduce the amount of water, so that the desired solid content is about 50%. 2524 g of a resorcin formalin resin aqueous solution having properties was obtained. This resorcin formalin resin aqueous solution having a solid content of about 50% does not contain an inorganic salt, and is a resorcin formalin resin in which the content of resorcin formalin resin of resorcin monomer and resorcin pentanuclear is reduced.

  The obtained resorcin formalin resin was dissolved in tetrahydrofuran and subjected to gel permeation chromatography analysis to measure the distribution of unreacted resorcin to resorcin pentanuclear or higher. The obtained chromatogram is shown in FIG. The calculated peak area ratio is shown in Table 1.

  Table 1 also shows the analysis results of the reaction solution before 37% formalin was dropped for the second time. The gel permeation chromatography analysis conditions are the same as in Example 1.

[Example 3]
2660 g of water, 1710 g of calcium chloride, 738 g of resorcin, and 300 g of methyl ethyl ketone were placed in a 5 L glass Kolben, dissolved at 60 ° C., and 9 g of 35% hydrochloric acid was placed in the reaction vessel. The reaction system was cooled to 50 ° C., and while maintaining 50 ° C., 326 g of 37% formalin was added dropwise over 45 minutes. After completion of the dropwise addition, the mixture was further stirred at 50 ° C. for 1 hour to promote a liquid-liquid heterogeneous reaction. Thereafter, 27 g of 37% formalin was added dropwise over 45 minutes, and after completion of the addition, the mixture was further stirred at 50 ° C. for 1 hour to promote a liquid-liquid heterogeneous reaction. The reaction system was allowed to stand while maintaining the same temperature to separate into two layers, and the lower aqueous phase was extracted. The organic phase is diluted with 1000 g of methyl ethyl ketone, 500 g of water is added, the reaction system is further stirred for 1 hour while maintaining the same temperature, and after standing, it is separated into two layers, the aqueous phase is extracted, and methyl ethyl ketone of resorcin formalin resin is obtained. A solution was obtained. It was diluted again with 1000 g of methyl ethyl ketone, and dehydrated by distillation at the azeotropic temperature of water and methyl ethyl ketone. Next, the solution was cooled to room temperature and filtered to obtain a methyl ethyl ketone solution of resorcin formalin resin. The obtained methyl ethyl ketone solution of resorcin formalin resin is put into the reaction vessel again, water is added and distillation is performed at the azeotropic temperature, methyl ethyl ketone is removed, the water content is reduced, and the target solid content is about 50. 1683 g of a resorcin formalin resin aqueous solution having a moderate fluidity of 1% was obtained. This resorcin formalin resin aqueous solution having a solid content of about 50% does not contain an inorganic salt, and is a resorcin formalin resin in which the content of resorcin formalin resin of resorcin monomer and resorcin pentanuclear is reduced.

  The obtained resorcin formalin resin was dissolved in tetrahydrofuran and subjected to gel permeation chromatography analysis to measure the distribution of unreacted resorcin to resorcin pentanuclear or higher. The obtained chromatogram is shown in FIG. The calculated peak area ratio is shown in Table 1.

  Table 1 also shows the analysis results of the reaction solution before 37% formalin was dropped for the second time. The gel permeation chromatography analysis conditions are the same as in Example 1.

[Example 4]
2660 g of water, 1710 g of calcium chloride, 738 g of resorcin, and 300 g of methyl ethyl ketone were placed in a 5 L glass Kolben, dissolved at 60 ° C., and 9 g of 35% hydrochloric acid was placed in the reaction vessel. The reaction system was cooled to 50 ° C., and while maintaining 50 ° C., 353 g of 37% formalin was added dropwise over 45 minutes, and after completion of the dropwise addition, the mixture was further stirred at 50 ° C. for 1 hour to proceed a liquid-liquid heterogeneous reaction. The reaction system was allowed to stand while maintaining the same temperature and separated into two layers, and the lower aqueous phase was extracted to obtain a methyl ethyl ketone solution of resorcin formalin resin. The organic phase was diluted with 1000 g of methyl ethyl ketone, 500 g of water was added, the reaction system was further stirred for 1 hour while maintaining 50 ° C., allowed to stand, separated into two layers, and the aqueous phase was extracted. It was diluted again with 1000 g of methyl ethyl ketone, and dehydrated by distillation at the azeotropic temperature of water and methyl ethyl ketone. Next, the solution was cooled to room temperature and filtered to obtain a methyl ethyl ketone solution of resorcin formalin resin.

  Water was added to the methyl ethyl ketone solution of the obtained resorcin formalin resin and distilled at an azeotropic temperature to remove methyl ethyl ketone and reduce the water content to obtain 1691 g of a resorcin formalin resin aqueous solution having a solid content of about 50%. .

  The obtained resorcin formalin resin was dissolved in tetrahydrofuran and subjected to gel permeation chromatography analysis to measure the distribution of unreacted resorcin to resorcin pentanuclear or higher. The obtained chromatogram is shown in FIG. The calculated peak area ratio is shown in Table 1. The gel permeation chromatography analysis conditions are the same as in Example 1.

[Example 5]
In Example 1, methyl ethyl ketone was used as the organic solvent, but in Example 5, methyl isobutyl ketone was used. Further, in Example 1, 53 kg of 37% formalin was dropped over 30 minutes, while in Example 5, 57 kg of 37% formalin was dropped over 30 minutes. Other reaction conditions and analysis conditions are the same as in Example 1. Thus, 243 kg of a resorcin formalin resin aqueous solution having a solid content of about 50% was obtained. The analysis results are shown in FIG.

[Example 6]
Tetrahydrofuran is used as the organic solvent, and the 37% formalin dropping amount is 57 kg. Other reaction conditions and analysis conditions are the same as in Example 1. 227 kg of a resorcin formalin resin aqueous solution having a solid content of about 50% was obtained. The analysis results are shown in FIG.
Examples 7 to 11 The solvents used in Examples 7 to 11 are shown in Table 1. The amount of 37% formalin dropped is 57 kg. Other reaction conditions and analysis conditions are the same as in Example 1. The analysis results are shown in Table 1.

[Comparative Example 1]
In a 2-liter three-necked flask, 265 g of water, 170 g of calcium chloride, and 63 g of resorcin were dissolved at 50 ° C., and then 0.8 g of 35% hydrochloric acid was placed in the reaction vessel. While maintaining the reaction system at 50 ° C., 26 g of 37% formalin was added dropwise over 5 hours, and after completion of the addition, the mixture was further stirred for 1 hour to promote a solid-liquid heterogeneous reaction. The produced resorcinol polynuclear product became a gum and entangled with a stirring bar, and the post-treatment was very troublesome. After discarding the aqueous phase, the gum-like substance was washed with 400 g of 39% calcium chloride aqueous solution. After removing the washing liquid, the gum-like substance was dried under reduced pressure, dissolved with 240 g of methyl ethyl ketone, insolubles were filtered off, and dried again under reduced pressure. Compared to the reaction of the example, a much longer reaction time was required. From the above, it was judged difficult to expand this reaction to an industrial scale.

[Comparative Example 2]
In a 1-liter three-necked flask, 150 g of water and 63 g of resorcin were added and dissolved at 50 ° C., and then 0.8 g of 35% hydrochloric acid was placed in the reaction vessel. While maintaining the reaction system at 50 ° C., 26 g of 37% formalin was added dropwise over 5 hours, and after completion of the addition, the reaction was further stirred for 1 hour. After discarding the aqueous phase, it was washed with 400 g of water. After removing the washing solution, it was dried under reduced pressure, dissolved with 240 g of methyl ethyl ketone, filtered to remove insoluble matter, and dried again under reduced pressure. Although an attempt was made to dissolve water by adding water to the reaction product, it could not be made into an aqueous solution. This is presumably because the content of resorcin formalin resin having five or more nuclei is high.

  Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

  This application is based on a Japanese patent application filed on Oct. 7, 2003 (Japanese Patent Application No. 2003-348496), the contents of which are incorporated herein by reference.

  Since the production method employs a liquid-liquid heterogeneous reaction, it is possible to reduce both the resorcin monomer content and the resorcin formalin resin content of resorcin pentanuclear or higher. The reaction time can be shortened, and the reaction can be completed in a single stage reaction. Since all the processes are performed in the same reactor, industrial production is possible and the cost is advantageous. Moreover, according to the said manufacturing method, a resorcin formalin resin which does not contain an inorganic salt and has moderate fluidity when made into an aqueous solution can be provided.

  The resorcin formalin resin of the present invention does not contain an inorganic salt, has an appropriate fluidity, and has an excellent adhesion to rubber and fibers, so it is useful as an adhesive for tires and an adhesive for rubber hoses. is there.

2 is a gel permeation chromatogram obtained in Example 1. 2 is a gel permeation chromatogram obtained in Example 2. 2 is a gel permeation chromatogram obtained in Example 3. 6 is a gel permeation chromatogram obtained in Example 4. 6 is a gel permeation chromatogram obtained in Example 5. 6 is a gel permeation chromatogram obtained in Example 6.

Claims (8)

  (A) 20 to 150 parts by mass of resorcin (A) is added to 100 parts by mass of water in an aqueous solvent, and 20 to 80 parts by mass of inorganic salt (B) is added to 100 parts by mass of water. The organic solvent (C) having a solubility parameter of 7.0 to 12.5, which is added within the range and dissolves the resorcin formalin resin, is added in an amount of 10 to 200 parts by mass with respect to 100 parts by mass of the resorcin (A). ) At a liquid temperature equal to or lower than the boiling point of) to form a two-phase system in which solid content does not remain, add a catalytic amount of an organic acid or an inorganic acid (D), and maintain the reaction system at 0 to 60 ° C. ˜40% formalin (E) is added dropwise over 1 to 300 minutes with stirring at a ratio of formaldehyde / resorcin = 0.3 to 0.8 mol with respect to resorcin (A). Stir for a minute to make the liquid non-uniform (B) The reaction system is allowed to stand while maintaining the reaction temperature and separated into two layers, the aqueous layer is removed, and the organic solvent (C) is added to the reaction product layer, which is an organic solvent layer. The reaction product is added in an amount equal to or 5 times the amount of the reaction product, diluted, half the amount of the organic solvent is added, and the reaction system is stirred while maintaining the temperature below the boiling point. And removing the aqueous layer to obtain a resorcin formalin resin, which does not contain an inorganic salt, has a reduced content of resorcin formalin resin of resorcin monomer and resorcin pentanuclear or more, and a one-step reaction and liquid Resorcin formalin resin produced by a production method in which all steps including distribution are performed in the same reactor.   The aforementioned 1 to 40% formalin (E) is intermittently added dropwise over 20 to 300 minutes with stirring at a ratio of formaldehyde / resorcin = 0.3 to 0.8 mol with respect to resorcin (A). The resorcin formalin resin according to claim 1, wherein the resorcin formalin resin is added.   The peak area corresponding to the resorcin pentanuclear or more obtained by gel permeation chromatography analysis of the resorcin formalin resin described above is 30% to 55% with respect to the entire peak area, and corresponds to the resorcin monomer. The resorcin formalin resin according to claim 1, wherein the peak area is 3% to 9% with respect to the total peak area.   The resorcin formalin resin according to any one of claims 1 to 3, wherein the organic solvent (C) is an organic solvent having a solubility parameter of 9.0 to 11.0. The resorcin formalin resin according to any one of claims 1 to 4, wherein the organic solvent (C) is an organic solvent (C) represented by the following general formula [1].
General formula [1]

[Wherein, m represents 0 or 1, and n represents 0 or 1. R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are each independently a methyl group, an ethyl group, an n-propyl group, a 2-propyl group, an n-butyl group, a secondary butyl group, an isobutyl group, or a tertiary butyl group. Represents. When m = n = 0, R ₁ and R ₂ may be combined to form a ring, and when m = 1 and n = 0, R ₂ and R ₃ may be combined to form a ring. Well, when m = n = 1, R ₃ and R ₄ may combine to form a ring. ]   The resorcin formalin resin according to any one of claims 1 to 5, wherein the organic solvent (C) is used as a mixture of two or more kinds.   To the resorcin formalin resin in the organic solvent (C) solution of the resorcin formalin resin in step (b) described above, 1 to 10 times the amount of water is added by weight, and the organic solvent (C) is removed by distillation. The resorcin formalin resin according to any one of claims 1 to 6, characterized in that a resorcin formalin resin aqueous solution having a moderate fluidity with a reaction product concentration of 30 to 80% is finally obtained.   The organic solvent (C) was diluted by adding 2 to 10 times the weight of the reaction product to the organic solvent layer which was separated into two layers after removing the aqueous layer after standing in the step (b), and water and organic The resorcin formalin according to any one of claims 1 to 7, wherein the solvent is dehydrated by distillation at an azeotropic temperature of the solvent, and then cooled to room temperature and then solids are removed by filtration. resin.

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