JP2013151603A - Method for producing condensate of resorcin and acetone - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a condensate of resorcin and acetone, in which the residual amount of unreacted resorcin is reduced.SOLUTION: Provided is a method for producing a condensate of resorcin and acetone, the condensate satisfying the conditions (1), (2) and (3) described below. The method for producing a condensate of resorcin and acetone comprises a first step where resorcin and acetone are reacted in the presence of an acid but in the absence of a solvent. (1) The area ratio of the peak of 2,4,4-trimethyl-2'-4'-7-trihydroxyflavan to the total area of all the peaks as determined by gel permeation chromatography (differential refractive index detection) is 25-55%. (2) The area ratio of the first elution peak to the total area of all the peaks as determined by gel permeation chromatography (differential refractive index detection) is 10-25%. (3) The weight average molecular weight of the first elution peak is 800 or more.

Description

  The present invention relates to a method for producing a condensate of resorcin and acetone.

A condensate of resorcin and acetone is useful as a reinforcing agent for various rubber compositions.
In Patent Document 1, after resorcin and acetone are reacted in the presence of an acid and an organic solvent, the acid is neutralized with an aqueous sodium hydroxide solution, and the neutralized mixture is dried under reduced pressure to obtain resorcin and A process for obtaining a condensate with acetone is described.

JP 2004-2431 A

  In the conventional production method, a large amount of unreacted resorcinol may remain.

The present invention includes the following inventions.
[1] including a first step of reacting resorcin and acetone in the presence of an acid and in the absence of a solvent,
A method for producing a condensate of resorcin and acetone satisfying the following (1), (2) and (3).
(1) The ratio of the peak area derived from 2,4,4-trimethyl-2 ′, 4 ′, 7-trihydroxyflavan to the total area of all peaks when gel permeation chromatography (differential refractive index detection) was analyzed (2) When gel permeation chromatography (differential refractive index detection) is analyzed, the area ratio of the first eluting peak to the total area of all peaks is in the range of 10 to 25%. (3) The weight average molecular weight of the first elution peak is in the range of 800 or more.

[2] The production method according to [1], wherein the first step is a step of reacting resorcin and acetone at −5 to 45 ° C. in the presence of an acid and in the absence of a solvent.

[3] a first step in which resorcin and acetone are reacted at −5 to 45 ° C. in the presence of an acid and in the absence of a solvent;
A second step of mixing the mixture obtained in the first step and the organic solvent;
A third step of heating the mixture obtained in the second step to 50 to 70 ° C .;
The production method according to [1] or [2].

[4] A first step in which resorcin and acetone are reacted at −5 to 45 ° C. in the presence of an acid and in the absence of a solvent;
A fourth step of mixing the mixture obtained in the first step and the base;
A fifth step of washing the mixture obtained in the fourth step with water;
The production method according to any one of [1] to [3].

[5] A first step of reacting resorcin and acetone in the presence of an acid and in the absence of a solvent at −5 to 45 ° C .;
A second step of mixing the mixture obtained in the first step and the organic solvent;
A third step of heating the mixture obtained in the second step to 50 to 70 ° C .;
A fourth step of mixing the mixture obtained in the third step and the base;
A fifth step of washing the mixture obtained in the fourth step with water;
The production method according to any one of [1] to [4], comprising:

[6] A condensate obtained by the production method according to any one of [1] to [5].

[7] A rubber composition comprising a condensate obtained by the production method according to any one of [1] to [5], a rubber component, a filler, and a sulfur component.

[8] A tire belt comprising a steel cord coated with the rubber composition according to [7].

[9] A tire carcass including a carcass fiber cord coated with the rubber composition according to [7].

[10] A tire tread or a tire undertread comprising the rubber composition according to [7].

[11] A pneumatic tire produced by processing the rubber composition according to [7].

  According to the production method of the present invention, the residual amount of unreacted resorcin can be reduced.

Hereinafter, the present invention will be described in detail.
<Step of reacting resorcin and acetone in the presence of an acid and in the absence of a solvent (hereinafter sometimes referred to as “first step”)>
Commercially available resorcinol and acetone can be used. The amount of acetone used is preferably in the range of 1 to 6 mol and more preferably in the range of 1.5 to 4 mol with respect to 1 mol of resorcin. If the amount of acetone used is 1 mol or more, it is preferred because the content of resorcin in the resulting condensate tends to be reduced.

  The acid acts as a catalyst in the reaction between resorcin and acetone, and may be hereinafter referred to as “acid catalyst”. Examples thereof include benzenesulfonic acid, p-toluenesulfonic acid, p-toluenesulfonic acid hydrate, oxalic acid, phosphoric acid, polyphosphoric acid, borofluoric acid, hydrochloric acid, sulfuric acid and the like. Among these, at least one acid selected from the group consisting of p-toluenesulfonic acid, p-toluenesulfonic acid hydrate, hydrochloric acid, and sulfuric acid is preferable. These acids can be used as they are or as an aqueous solution having an appropriate concentration. Although there is no restriction | limiting in particular in the usage-amount of an acid, the range of 0.1-10 mol is preferable with respect to 100 mol of resorcinol, and the range of 0.5-5 mol is more preferable.

  The reaction temperature of the reaction between resorcin and acetone is preferably in the range of −5 ° C. or more and 45 ° C. or less. The progress of the reaction can be confirmed by ordinary analytical means such as gas chromatography (GC), high performance liquid chromatography (HPLC), gel permeation chromatography (GPC), etc., while confirming the progress of the reaction, The end point can be determined.

  The mixing order of resorcin, acetone, and acid is not particularly limited, and for example, resorcin and acetone can be mixed, and the resulting mixture and acid can be mixed under reaction temperature conditions.

７，７’−ジヒドロキシ−４，４，４’，４’−テトラメチル−２，２’−スピロビクロマン（下記の式で示される化合物）、

４，６−ビス（７−ヒドロキシ−２，４，４−トリメチルクロマン−２−イル）−１，３−ベンゼンジオール（式（Ｉ）で表される化合物）及びその異性体、

２，４−ビス（７−ヒドロキシ−２，４，４−トリメチルクロマン−２−イル）−１，３−ベンゼンジオール（式（ＩＩ）で表される化合物）及びその異性体、

式（ＩＩＩ）で表される化合物及びその異性体、

式（ＩＶ）で表される化合物及びその異性体、

［式（ＩＶ）中、ｎは２以上の整数を表す。］
等が挙げられる。 As a compound contained in the condensate of resorcin and acetone, in addition to 2,4,4-trimethyl-2′4′7-trihydroxyflavan (a compound represented by the following formula),

7,7′-dihydroxy-4,4,4 ′, 4′-tetramethyl-2,2′-spirobichroman (compound represented by the following formula),

4,6-bis (7-hydroxy-2,4,4-trimethylchroman-2-yl) -1,3-benzenediol (compound represented by formula (I)) and isomers thereof,

2,4-bis (7-hydroxy-2,4,4-trimethylchroman-2-yl) -1,3-benzenediol (compound represented by formula (II)) and isomers thereof,

Compounds represented by formula (III) and isomers thereof,

Compounds represented by formula (IV) and isomers thereof,

[In the formula (IV), n represents an integer of 2 or more. ]
Etc.

The mixture obtained in the first step may be directly subjected to the fourth step which will be described later, or may be further subjected to the fourth step after being subjected to the second and third steps which will be described later if necessary. .

<Step of mixing the mixture obtained in the first step and the organic solvent (hereinafter sometimes referred to as “second step”)>
In the third step, which will be described later, in order to maintain the content of 2,4,4-trimethyl-2′4′7-trihydroxyflavan in the third step described later, the mixture obtained in the first step and the organic solvent Is a step of crystallizing 2,4,4-trimethyl-2′4′7-trihydroxyflavan by mixing.

Examples of the organic solvent include aliphatic hydrocarbons, aromatic hydrocarbons, halogen-substituted aromatic hydrocarbons, and the like. Specific examples of the aliphatic hydrocarbon are hexane, heptane, octane, decane, and the like. Specific examples of the aromatic hydrocarbon are toluene, xylene, ethylbenzene, and the like. Specific examples of the halogen-substituted aromatic hydrocarbon are: Chlorobenzene, dichlorobenzene and the like. Aromatic hydrocarbons are preferred, and toluene or xylene is more preferred. The amount of the organic solvent used is preferably in the range of 0.5 to 3 parts by weight with respect to 1 part by weight of resorcin.

  The temperature at which the organic solvent is mixed may be the same as the reaction temperature in the first step, but in order to promote crystallization of 2,4,4-trimethyl-2′4′7-trihydroxyflavan, the first step The reaction temperature may be lower than the reaction temperature at. As temperature in that case, the range of -5-20 degreeC is preferable.

<Step of raising the temperature of the mixture obtained in the second step to 50 to 70 ° C. (hereinafter sometimes referred to as “third step”)>
The third step is a step of further reacting unreacted resorcin and acetone by carrying out the reaction by raising the temperature to 50 to 70 ° C. in the presence of an organic solvent.

The progress of the reaction can be confirmed by ordinary analytical means such as gas chromatography (GC), high performance liquid chromatography (HPLC), gel permeation chromatography (GPC), etc., while confirming the progress of the reaction, The end point can be determined.

<Step of mixing the mixture obtained in the first step or the third step and the base (hereinafter sometimes referred to as “fourth step”)>
As the base, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkali metal hydrogen carbonates such as sodium hydrogen carbonate, alkali metal carbonates such as sodium carbonate, and the like can be used. Is preferred, and sodium hydroxide is more preferred. The base is preferably used as an aqueous solution having an appropriate concentration.

  The pH of the mixture obtained by mixing with a base is preferably in the range of 5-9, more preferably in the range of 6-8.

<Step of washing the mixture obtained in the fourth step (hereinafter sometimes referred to as “fifth step”)>
Washing with water is a step of removing unreacted resorcin by mixing the mixture obtained in the fourth step with water and separating and washing. When the mixture obtained in the fourth step is a slurry solution in which a condensate of resorcin and acetone is deposited, the precipitate may be dissolved by mixing an organic solvent. The organic solvent is not particularly limited as long as it is an organic solvent that can dissolve precipitates among those that can be used in the first step, but acetone is preferably used from the viewpoint of liquid separation. The amount of the organic solvent used is preferably 2 parts by weight or less with respect to 1 part by weight of resorcin used in the first step. The amount of water used is preferably in the range of 0.5 to 3 parts by weight with respect to 1 part by weight of resorcin used in the first step.

  For the purpose of increasing resorcin removal efficiency, the mixture may be washed with water under alkaline conditions by mixing a mixed solution obtained by mixing water in the fifth step and a base. The pH of the mixed solution obtained by mixing with the base may be in the range of 7 to 11, and more preferably in the range of 8 to 10. As the base, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkali metal hydrogen carbonates such as sodium hydrogen carbonate, alkali metal carbonates such as sodium carbonate, and the like can be used. Is preferred, and sodium hydroxide is more preferred. The base is preferably used as an aqueous solution having an appropriate concentration.

  The temperature when washing and liquid separation is preferably in the range of 45 ° C or higher and 80 ° C or lower. The amount of residual resorcin can be confirmed by ordinary analytical means such as gas chromatography (GC), high performance liquid chromatography (HPLC), gel permeation chromatography (GPC), and while confirming the decrease in resorcin, The required number of water washing can be determined.

<Post-processing process>
The condensate of resorcin and acetone can be taken out by removing the organic solvent by subjecting the mixture obtained in the fifth step to a post-treatment step including a treatment such as a filtration treatment and a concentration treatment.
The residual ratio of resorcin is preferably 2.0% by weight or less, and more preferably 1.0% by weight or less.

<Condensate obtained>
In the present invention, the “first eluting peak” means a peak having the shortest retention time among all peaks in a chromatogram obtained by analysis by gel permeation chromatography (differential refractive index detection). The “second eluting peak” means a peak having the second shortest retention time among all peaks in a chromatogram obtained by analysis by gel permeation chromatography (differential refractive index detection). “Elution peak” means a peak having the third shortest retention time among all peaks in a chromatogram obtained by analysis by gel permeation chromatography (differential refractive index detection).
In gel permeation chromatography (differential refractive index detection), the compound group consisting of the compound represented by formula (IV) and its isomer is taken as the first elution peak from the compound represented by formula (III) and its isomer. The compound group consisting of the compound represented by formula (I) and its isomer, and the compound group consisting of the compound represented by formula (II) and its isomer as the third elution peak, Detected.

The obtained condensate satisfies (1), (2) and (3).
(1) The ratio of the peak area derived from 2,4,4-trimethyl-2 ′, 4 ′, 7-trihydroxyflavan to the total area of all peaks when gel permeation chromatography (differential refractive index detection) was analyzed (2) When gel permeation chromatography (differential refractive index detection) is analyzed, the area ratio of the first eluting peak to the total area of all peaks is in the range of 10 to 25%. (3) The weight average molecular weight of the first elution peak is in the range of 800 or more.

The weight average molecular weight of the first elution peak when gel permeation chromatography (differential refractive index detection) is analyzed is preferably 800-1200.
The content of 2,4,4-trimethyl-2′4′7-trihydroxyflavan contained in the obtained condensate is preferably in the range of 25 to 55% by weight, more preferably in the range of 30 to 50% by weight. preferable.
4,6-bis (7-hydroxy-2,4,4-trimethylchroman-2-yl) -1,3-benzenediol (compound represented by formula (I)) contained in the obtained condensate And isomers thereof, and 2,4-bis (7-hydroxy-2,4,4-trimethylchroman-2-yl) -1,3-benzenediol (compound represented by formula (II)) and its The total content of isomers is preferably in the range of 20 to 30% by weight.
The total content of the compound represented by formula (III) and its isomer contained in the obtained condensate is preferably in the range of 10 to 20% by weight.
The total content of the compound represented by formula (IV) and the isomers contained in the obtained condensate is preferably in the range of 10 to 25% by weight, and more preferably in the range of 10 to 20% by weight.

The softening point of the resulting condensate of resorcin and acetone is preferably 160 ° C. or lower, and more preferably 140 ° C. or lower.
The resulting condensate of resorcin and acetone can be used as a rubber reinforcing agent. It is particularly useful as a reinforcing agent for rubber for tires.

  Next, a rubber composition containing a condensate of resorcin and acetone, a rubber component, a filler, and a sulfur component will be described.

  Examples of the rubber component include natural rubber, styrene butadiene copolymer rubber, butadiene rubber, isoprene rubber, and the like, and rubber components containing these as main components. The amount of the condensate of resorcin and acetone is preferably in the range of 0.5 to 3 parts by weight and more preferably in the range of 1 to 2 parts by weight with respect to 100 parts by weight of these rubber components.

  Examples of the filler include carbon black, silica, talc, clay and the like that are usually used in the rubber field, and carbon black is more preferably used. As the carbon black, carbon black such as HAF (High Abrasion Furnace), SAF (Super Abrasion Furnace), ISAF (Intermediate SAF) is preferable. It is also preferable to combine several kinds of fillers such as a combination of carbon black and silica. The amount of the filler used is preferably in the range of 10 to 100 parts by weight per 100 parts by weight of the rubber component. More preferably, it is 30-70 weight part.

  Examples of the sulfur component include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, and highly dispersible sulfur. Powdered sulfur and insoluble sulfur are preferred. The amount of the sulfur component used is preferably in the range of 1 to 10 parts by weight per 100 parts by weight of the rubber component. More preferably, it is 2 to 6 parts by weight.

  Furthermore, a rubber composition can be produced using a vulcanization accelerator, a methoxylated methylol melamine resin, an organic cobalt compound, zinc oxide and the like.

  Examples of vulcanization accelerators include thiazole-based vulcanization accelerators and sulfur compounds described on pages 412 to 413 of Rubber Industry Handbook <Fourth Edition> (issued by the Japan Rubber Association on January 20, 1994). Examples thereof include phenamide vulcanization accelerators and guanidine vulcanization accelerators. The amount of the vulcanization accelerator used is preferably in the range of 0.5 to 1 part by weight per 100 parts by weight of the rubber component. More preferably, it is 0.6-0.8 weight part.

  Examples of the methoxylated methylol melamine resin include those usually used in the rubber industry such as hexakis (methoxymethyl) melamine, pentakis (methoxymethyl) methylol melamine, and tetrakis (methoxymethyl) dimethylol melamine. Hexakis (methoxymethyl) melamine alone or a mixture based on it is preferred. These methoxylated methylol melamine resins can be used alone or in combination, and the blending amount thereof is preferably in the range of 0.5 to 6.0 parts by weight with respect to 100 parts by weight of the rubber component. A range of ˜3.0 parts by weight is more preferable.

  Examples of the organic cobalt compound include acid cobalt salts such as cobalt naphthenate and cobalt stearate, and fatty acid cobalt / boron complex compounds (for example, trade name “Manobond C (registered trademark)” manufactured by Manchem). . The amount of the organic cobalt compound used is preferably in the range of 0.1 to 0.4 parts by weight, more preferably in the range of 0.1 to 0.3 parts by weight, based on 100 parts by weight of the rubber component.

  In addition, various rubber chemicals commonly used in the rubber industry, for example, antioxidants such as antioxidants and ozone deterioration inhibitors, peptizers, processing aids, waxes, oils, stearic acid, tackifiers One or more of these may be used in combination as necessary. The compounding amount of these chemicals varies depending on the use of the rubber composition, but an amount in a range usually used in the rubber industry can be used.

  The rubber composition can be derived into a rubber product through a process such as molding and vulcanization, for example, in accordance with a method commonly practiced in the rubber industry. In particular, it can be used for various members of tires such as cap treads, under treads, belts, carcass, beads, sidewalls, rubber chafers and the like. Further, it can also be used for anti-vibration rubbers for automobiles such as engine mounts, strut mounts, bushes and exhaust hangers, hoses, rubber belts and the like.

  For example, a tire belt can be manufactured by coating a steel cord with a rubber composition. Steel cords are usually used in an aligned state.

  From the viewpoint of adhesion to rubber, the steel cord is preferably plated with brass, zinc, or an alloy containing nickel or cobalt, and is preferably subjected to brass plating. is there. In particular, a steel cord subjected to a brass plating process in which the Cu content in the brass plating is 75% by weight or less, preferably 55 to 70% by weight is suitable. The twist structure of the steel cord is not limited.

  A plurality of belts may be laminated and used. The belt is mainly used as a carcass reinforcing material.

  In addition, for example, a carcass can be manufactured by extruding a rubber composition in accordance with a carcass shape of a tire and attaching the rubber composition on the upper and lower sides of a carcass fiber cord. The carcass fiber cord is usually used in a state of being aligned in parallel. As the carcass fiber cord, preferred is an inexpensive polyester that has good elastic modulus and fatigue resistance and excellent creep resistance. These are used as a tire reinforcing material by laminating one sheet or a plurality of sheets.

  A pneumatic tire can be manufactured by a normal manufacturing method using a rubber composition. For example, a rubber composition is extruded to obtain a tire member, which is pasted and molded on another tire member by a normal method on a tire molding machine to form a raw tire. The green tire is heated and pressed in a vulcanizer to obtain a tire.

Hereinafter, the present invention will be specifically described with reference to Examples and Test Examples. In the following examples, the contents of 2,4,4-trimethyl-2′4′7-trihydroxyflavan, resorcin, and the like were the same as the values determined by the GPC area percentage method.
In GPC analysis, the compound group consisting of the compound represented by formula (IV) and its isomer is the first eluting peak, and the compound group consisting of the compound represented by formula (III) and its isomer is the second eluting peak. As a result, the compound represented by the formula (I) and its isomer, and the compound group consisting of the compound represented by the formula (II) and its isomer were detected as the third elution peak.
The softening point was carried out according to JIS K 6220-1.
<GPC analysis conditions>
Column: TOSOH TSGel Super HZ2000 (4.6mmφx150cm) and two TOSOH TSGel Super HZ1000 (4.6mmφx150cm) connection temperature: 40 ° C
Mobile phase: Tetrahydrofuran Detector: RI

Example 1
A 500 ml four-necked flask equipped with a thermometer, a stirrer and a condenser was charged with 88.1 g (0.80 mol) of resorcin, and after the inside of the flask was purged with nitrogen, 69.7 g (1.20 mol) of acetone was charged. The temperature was raised to 35 ° C. Thereto was charged 1.20 g of 98% sulfuric acid, and the resulting mixture was kept at an internal temperature of 35 ° C. for 5 hours. Thereafter, 132 g of toluene was charged with the internal temperature kept at 35 ° C., and neutralized with a 10% aqueous sodium hydroxide solution.
After the reaction solution was transferred to a 1000 ml separable flask equipped with a thermometer, a stirrer and a condenser, 69.7 g (1.20 mol) of acetone was charged, and the reaction product was completely heated by raising the internal temperature to 60 ° C. Dissolved in. Furthermore, 220 g of hot water was charged at the same temperature, and the pH was adjusted to alkaline (9.0) with a 10% aqueous sodium hydroxide solution, and then unreacted resorcin was removed by liquid separation washing. Separation and washing were repeated until the content of resorcin was 1% or less, followed by drying at 80 ° C. for 12 hours under reduced pressure of 1 KPa or less to obtain 88 g of a condensate of resorcin and acetone. The contents of 2,4,4-trimethyl-2′4′7-trihydroxyflavan and resorcin in the obtained condensate were as follows.
2,4,4-trimethyl-2'4'7-trihydroxyflavan: 38.6%
Resorcin: 0.3%
First eluting peak: 13.4%
Weight average molecular weight of first eluting peak: 995
Second eluting peak: 17.9%
Third elution peak: 29.7%
Softening point 114 ° C

Example 2
A 500 ml four-necked flask equipped with a thermometer, a stirrer and a condenser was charged with 88.1 g (0.80 mol) of resorcin, and after the inside of the flask was purged with nitrogen, 69.7 g (1.20 mol) of acetone was charged. The temperature was raised to 35 ° C. Thereto was charged 4.00 g of 98% sulfuric acid, and the resulting mixture was kept at an internal temperature of 35 ° C. for 3 hours. Thereafter, 132 g of toluene was charged with the internal temperature kept at 35 ° C., and the mixture was stirred for 15 minutes, and then the temperature was raised to 60 ° C. and kept for another 6 hours. Thereafter, the reaction solution was neutralized with a 10% aqueous sodium hydroxide solution.
After the reaction solution was transferred to a 1000 ml separable flask equipped with a thermometer, a stirrer and a condenser, 83.6 g (1.44 mol) of acetone was charged and the reaction product was completely heated by raising the temperature to 60 ° C. Dissolved in. Furthermore, 220 g of hot water was charged at the same temperature, and the pH was adjusted to alkaline (9.0) with a 10% aqueous sodium hydroxide solution, and then unreacted resorcin was removed by liquid separation washing. Separation and washing were repeated until the content of resorcin was 1% or less, followed by drying at 80 ° C. for 12 hours under reduced pressure of 1 KPa or less to obtain 110 g of a condensate of resorcin and acetone. The contents of 2,4,4-trimethyl-2′4′7-trihydroxyflavan and resorcin in the obtained condensate were as follows.
2,4,4-trimethyl-2'4'7-trihydroxyflavan: 42.6%
Resorcin: 0.3%
First eluting peak: 16.4%
Weight average molecular weight of first elution peak: 1054
Second eluting peak: 17.6%
Third elution peak: 22.8%
Softening point 115 ° C

Example 3
A 500 ml four-necked flask equipped with a thermometer, a stirrer and a condenser was charged with 88.1 g (0.80 mol) of resorcin while cooling in an ice bath, and the inside of the flask was purged with nitrogen, followed by 69.7 g of acetone (1. 20 mol) was charged and kept at 0 ° C. Thereto was charged 4.00 g of 98% sulfuric acid, and the resulting mixture was kept at 0 ° C. for 4 hours. Subsequently, 132 g of toluene was charged with the internal temperature kept at 0 ° C., stirred for 15 minutes, then heated to an internal temperature of 60 ° C. and further kept for 4 hours. Thereafter, the reaction solution was neutralized with a 10% aqueous sodium hydroxide solution.
After the reaction solution was transferred to a 1000 ml separable flask equipped with a thermometer, a stirrer and a condenser, 83.6 g (1.44 mol) of acetone was charged and the reaction product was completely heated by raising the temperature to 60 ° C. Dissolved in. Furthermore, 220 g of hot water was charged at the same temperature, and the pH was adjusted to alkaline (9.0) with a 10% aqueous sodium hydroxide solution, and then unreacted resorcin was removed by liquid separation washing. Separation and washing were repeated until the content of resorcin was 1% or less, followed by drying at 80 ° C. for 12 hours under reduced pressure of 1 KPa or less to obtain 101 g of a resorcin-acetone condensate. The contents of 2,4,4-trimethyl-2′4′7-trihydroxyflavan and resorcin in the obtained condensate were as follows.
2,4,4-trimethyl-2'4'7-trihydroxyflavan: 40.2%
Resorcin: 0.4%
First eluting peak: 12.3%
Weight average molecular weight of first elution peak: 984
Second eluting peak: 17.3%
Third elution peak: 29.6%
Softening point 117 ° C

According to the production method of the present invention, the residual amount of unreacted resorcin can be reduced.
The condensate of resorcin and acetone obtained by the production method of the present invention is excellent in performance as a reinforcing agent for various rubber compositions, and can also prevent deterioration of the working environment due to transpiration of residual resorcin during processing of the rubber composition. Therefore, it is industrially advantageous.

Claims (11)

Comprising a first step of reacting resorcin and acetone in the presence of an acid and in the absence of a solvent,
A method for producing a condensate of resorcin and acetone satisfying the following (1), (2) and (3).
(1) The ratio of the peak area derived from 2,4,4-trimethyl-2 ′, 4 ′, 7-trihydroxyflavan to the total area of all peaks when gel permeation chromatography (differential refractive index detection) was analyzed (2) When gel permeation chromatography (differential refractive index detection) is analyzed, the area ratio of the first eluting peak to the total area of all peaks is in the range of 10 to 25%. (3) The weight average molecular weight of the first elution peak is in the range of 800 or more. The production method according to claim 1, wherein the first step is a step of reacting resorcin and acetone at -5 to 45 ° C in the presence of an acid and in the absence of a solvent. A first step of reacting resorcin and acetone in the presence of an acid and in the absence of a solvent at −5 to 45 ° C .;
A second step of mixing the mixture obtained in the first step and the organic solvent;
A third step of heating the mixture obtained in the second step to 50 to 70 ° C .;
The manufacturing method of Claim 1 or 2 containing. A first step of reacting resorcin and acetone in the presence of an acid and in the absence of a solvent at −5 to 45 ° C .;
A fourth step of mixing the mixture obtained in the first step and the base;
A fifth step of washing the mixture obtained in the fourth step with water;
The manufacturing method of any one of Claims 1-3 containing this. A first step of reacting resorcin and acetone in the presence of an acid and in the absence of a solvent at −5 to 45 ° C .;
A second step of mixing the mixture obtained in the first step and the organic solvent;
A third step of heating the mixture obtained in the second step to 50 to 70 ° C .;
A fourth step of mixing the mixture obtained in the third step and the base;
A fifth step of washing the mixture obtained in the fourth step with water;
The manufacturing method in any one of Claims 1-4 containing this. A condensate obtained by the production method according to claim 1. The rubber composition containing the condensate obtained by the manufacturing method of any one of Claims 1-5, a rubber component, a filler, and a sulfur component. A tire belt comprising a steel cord coated with the rubber composition according to claim 7. A tire carcass comprising a carcass fiber cord coated with the rubber composition according to claim 7. A tire tread or a tire undertread comprising the rubber composition according to claim 7. A pneumatic tire produced by processing the rubber composition according to claim 7. ‘’