JPH0714963B2 - Method for producing hydrophilic polymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a novel polyisoprene or natural rubber having a high molecular weight, which is modified by a polymer reaction to its unsaturated double bond, to have an unsaturated double bond in the polymer structure. The present invention relates to a method for producing a hydrophilic polymer.

Various types of water-soluble polymers have been conventionally known. For example, natural polymers include alginic acid (sodium alginate), carboxymethyl cellulose (CM
C), saccharides such as methyl cellulose [MC: methyl etherification product of cellulose (25 to 32%)], and their chemically modified products, and further, as water-soluble polysaccharides by microorganisms, pullulan, dextran, xanthan gum, etc. Can also be mentioned. Examples of synthetic polymers include polyvinyl alcohol (poval), polyethylene oxide, sodium polyacrylate, and polyacrylamide.

The water-soluble polymer has been used in various ways in the field of water-soluble polymer materials while making use of the characteristics of each property.

For example, adhesives, paints, fiber processing agents, paste materials, Japanese paper / paperboard / papermaking viscous agents, emulsifiers, flocculants, liquid friction resistance reducers, thickeners, asphalt emulsifiers, agricultural chemical spreaders, pigment dispersions. Agents, latex thickeners, soil conditioners, printing agents, and other industrial fields, as well as ice cream additives, food processing,
It is also used in large quantities in bio-related fields such as pharmaceuticals / cosmetics, beer foam continuous stabilizer, diet foods, pharmaceutical tablets, and plasma expanders.

The total amount of water-soluble polymers used in these water-soluble polymer materials has reached several hundred thousand tons / year (Japan), and there is an increasing demand for water-soluble polymers with special characteristics.

On the other hand, attempts have also been made to make hydrophilic diene polymers having unsaturated double bonds, such as for electrodeposition coatings.

Originally, polyisoprene and diene polymers represented by natural rubber are insoluble in highly polar solvents such as water and alcohols, but if these polymers can be dissolved in water, alcohol, etc. It can be used in fields of application.

Therefore, various methods have been reported for making the diene polymer water-soluble, and they are roughly classified as follows.

(1) Maleation of polybutadiene or a method of further reacting the maleated product to increase hydrophilicity (2) Copolymerization of butadiene with other vinyl monomer,
Alternatively, a method of imparting hydrophilicity by synthesizing a butadiene derivative by the reaction of a butadiene monomer and polymerizing the special monomer (3) Epoxidizing polybutadiene and then opening the oxirane ring with a carboxylic acid, a secondary amine or a diamine (4) Method of making polymer hydrophilic by chemical modification (addition of sulfonic acid group, etc.) other than the above methods (1) to (3). Although the polymer obtained by the method is described as water-soluble or water-dilutable in the literature, in reality, it is in the form of a latex whose concept is different from water-soluble, or when it is mixed with a large amount of water such as cellosolves. Most of them are water-dilutable in the presence of a soluble organic solvent, and few are truly water-soluble.

Further, in the above-mentioned known method, the base polybutadiene used as an object to be chemically modified has a molecular weight of 1
Most of the low molecular weight (liquid) polybutadiene is less than 000, and it is rare when a high molecular weight polymer having a molecular weight of 10,000 or more is used.

As a result of earnest research aimed at making a high molecular weight diene-based polymer having an unsaturated double bond hydrophilic, the present inventors have found that the unsaturated double bond of a high molecular weight polyisoprene or natural rubber is contained at a specific ratio. Epoxidation and then the presence of one or more tertiary amines and saturated carboxylic acids selected from the group consisting of pyridines, picolines, lutidines, quinolines, isoquinolines, alkylimidazoles, pyrazines and their derivatives The inventors have found that a hydrophilic diene-based polymer can be obtained by heating below, and have reached the present invention.

The present invention was made based on the above findings, and 80% or more of unsaturated double bonds are cis 1,4-bonds and have a molecular weight of 10,00.
Characterized by epoxidizing 5 to 60 mol% of unsaturated double bonds of 0 or more polyisoprene or natural rubber, and then heating in the presence of a tertiary amine and a carboxylic acid to open the epoxy ring And a novel modified polymer obtained by the production method of the present invention is hydrophilic (in some cases, water-soluble) and has a high degree of unsaturated double bond in the polymer structure. It is a polymer of molecular weight, and it should be used not only in the conventionally known fields of application of water-soluble polymers, but also by taking advantage of its characteristics of having unsaturated double bonds (photosensitivity, imparting rubber-like properties, curing by thermal crosslinking, etc.). You can

The method for producing the hydrophilic polymer of the present invention will be described in detail below based on its embodiments.

Cis 1,4 used as a target for hydrophilization in the present invention
-Polyisoprene is a high-molecular-weight cis-1,4-bond having a cis-1,4-bond content of 80% or more and an average molecular weight of 10,000 or more.
It is polyisoprene.

Further, the natural rubber to be rendered hydrophilic in the present invention has various origins, production methods, and forms, but is not particularly limited. As the natural rubber, latex before processing into raw rubber can be used, but raw rubber is preferable as a raw material.

Natural rubber is generally considered to be high-molecular-weight polyisoprene having cis 1,4-bonds of 98% or more, and one containing a small amount of impurities such as proteins, sugars, and ash can also be used.

As the raw material rubber, polyisoprene is preferable, and particularly, polyisoprene having its Mooney viscosity (molecular weight) reduced by mastication within the range of 10,000 or more is preferable.

Thus, the present invention uses the above-mentioned cis-1,4-polyisoprene or natural rubber (hereinafter sometimes simply referred to as isoprene-based rubber) to partially epoxidize the rubber (first-stage reaction) and to produce epoxidized isoprene-based rubber. It is modified to be hydrophilic by carrying out a two-step reaction of opening the epoxy ring (second step reaction).

First, the partial epoxidation of isoprene-based rubber in the first stage reaction will be described.

What is important in this first-stage reaction is the proportion of unsaturated double bonds (epoxidation rate) of the isoprene-based rubber that is epoxidized by the partial epoxidation of the isoprene-based rubber.
5 to 60 mol%, preferably 10 to total unsaturated double bonds
It is to be ~ 45 mol%.

The isoprene-based rubber epoxidized exceeding the upper limit of the epoxidation rate becomes a gel or becomes insoluble in the solvent in the epoxy ring-opening reaction step of the next second step reaction.

Further, the isoprene-based rubber epoxidized below the lower limit of the above-mentioned epoxidation rate does not become hydrophilic even if the epoxy ring is opened in the next second step reaction, or becomes insufficient in hydrophilicity. Become.

In the present invention, the method for epoxidizing isoprene-based rubber is not particularly limited, and unsaturated double bond such as chlorohydrin method, direct oxidation method, hydrogen peroxide method, alkylhydroperoxide method, peracid method, etc. As a method for epoxidizing a compound having the above, a conventionally known method can be used.

As an example, the epoxidation of isoprene-based rubber by the peracid method (in situ-peracid method) will be described below.

The epoxidation of isoprene-based rubber by the peracid method is performed by adding an organic acid and hydrogen peroxide to a solution of the isoprene-based rubber in an inert organic solvent. The reaction formula is as follows.

RCO ₂ H + H ₂ O ₂ RCO ₃ H + H ₂ O (1) That is, the organic acid reacts with hydrogen peroxide to form a peracid, which acts on the unsaturated double bond of the isoprene rubber to epoxidize the isoprene rubber. It is considered that the organic acid generated in the above reaction formula (2) repeats the same reactions as in the above reaction formulas (1) and (2).

As the organic acid, formic acid, benzoic acid, acetic acid and the like can be used. Particularly, formic acid is preferably used because of a high peracid generation rate.

Further, as an inert organic solvent for isoprene-based rubber, a solvent that dissolves isoprene-based rubber, is sparingly soluble in water, and is inactive to hydrogen peroxide (or peracid), such as benzene, toluene, xylene, Hydrocarbons such as cyclohexane; halogenated hydrocarbons such as chloroform, carbon tetrachloride and chlorobenzene can be used alone or in admixture of two or more.

The solution of isoprene-based rubber in an inert organic solvent is usually 0 to 80% by adding the isoprene-based rubber to the inert organic solvent.
A method of dissolving the isoprene-based rubber in an inert organic solvent by stirring and mixing at 0 ° C, preferably 20-60 ° C for 1 minute to 1 hour, or adding a polymerization terminator such as water or hydrochloric acid to the isoprene-based rubber polymerization solution, It is obtained by a method of deashing by washing with water.

The epoxidation reaction conditions such as the concentration of the isoprene-based rubber in the above-mentioned solution of the isoprene-based rubber in the inert organic solvent, the amount of the organic acid and hydrogen peroxide added to the isoprene-based rubber, and the addition method thereof depend on the organic acid used. It is not limited because it varies depending on the type and the target epoxidation rate. For example, in the case of the peracid method using formic acid as the organic acid, the following reaction conditions are usually adopted.

The concentration of the isoprene-based rubber in the solution of the isoprene-based rubber in the inert organic solvent is about 1 to 30% by weight, the addition amount of formic acid is preferably 0.01 to 2 mol per 100 g of the isoprene-based rubber, and the addition amount of hydrogen peroxide is the isoprene-based rubber. It is preferably 0.1 to 4 mol per 100 g of rubber. The addition amount of these formic acid and hydrogen peroxide can be changed within the above range depending on the target epoxidation rate.

Further, hydrogen peroxide is preferably added as 20 to 60% by weight of hydrogen peroxide solution to the solution of the isoprene-based rubber in the inert organic solvent.

There is no particular limitation on the method of adding formic acid and hydrogen peroxide to the solution of the isoprene-based rubber in the inert organic solvent, but the solution obtained by adding the formic acid to the solution of the isoprene-based rubber in the inert organic solvent and mixing them is added to the solution. It is preferable to gradually add hydrogen peroxide solution having a concentration within the above range while maintaining the solution at 0 to 80 ° C.

After adding formic acid and hydrogen peroxide in the above-mentioned predetermined amount to the above-mentioned solution of isoprene-based rubber in an organic solvent, the mixed solution is heated at 0-80 ° C, preferably 20-60 ° C, preferably 10 ° C.
Epoxidize the isoprene rubber by stirring and mixing for 1 minute to 10 hours.

If the reaction temperature for epoxidation is lower than the lower limit, the isoprene-based rubber is difficult to epoxidize, and if it is higher than the upper limit, hydrogen peroxide and peracid are likely to be decomposed, which is dangerous.

In the epoxidation reaction system of the first step reaction or in the ring opening reaction system of the epoxy ring of the second step reaction described later, a small amount of a stabilizer such as 2,6- The-
Tertiary-butyl-P-cresol (BHT) and the like can be added, and addition of such stabilizers is the preferred method.

After completion of the epoxidation of the above-mentioned first-step reaction, it is preferable to separate the epoxidized isoprene-based rubber (epoxidized isoprene-based rubber) from the reaction product solution and then shift to the second-step reaction. You may transfer to a 2nd step reaction following the epoxidation reaction as it is, without separating from a production liquid.

Separation of the epoxidized isoprene-based rubber is carried out by a conventionally known separation method, for example, the reaction product solution obtained by epoxidation is washed with water at a relatively low temperature, and then a large amount of epoxidized isoprene-based rubber such as methyl alcohol is used. A method in which a rubber-like epoxidized isoprene-based rubber is deposited by separating it into a sparingly soluble organic solvent for rubber, or the reaction product solution is washed with water and then steam-distilled to remove impurities in the reaction product solution. A low boiling point substance such as an active organic solvent or formic acid (organic acid) may be removed by evaporation to deposit an epoxidized isoprene-based rubber for separation.

The second stage reaction is relatively high temperature (40-160 ℃) as described later.
If a large amount of hydrogen peroxide or formic acid remains, the polymer may gel during the reaction.
Even when the epoxidized isoprene-based rubber is transferred to the second stage reaction without being separated, it is preferable that the reaction product solution is washed with water at a relatively low temperature to remove most of hydrogen peroxide and formic acid.

Next, the ring-opening reaction of the epoxy ring of the epoxidized isoprene-based rubber in the second step reaction will be described.

In the ring-opening reaction of the epoxy ring in the second-step reaction, the isoprene-based rubber (epoxidized isoprene-based rubber) in which 5 to 60 mol% of the unsaturated double bond is epoxidized by the first-step reaction is used in the third step. It is heated in the presence of an amine and a saturated carboxylic acid to cause a reaction to open the epoxy ring, and the desired hydrophilic polymer is obtained through this second-step reaction. The concept of hydrophilicity referred to in the present invention is not limited to water solubility, and includes those soluble in lower alcohols such as methyl alcohol and ethyl alcohol.

The tertiary amine used in the second stage reaction of the present invention is
Alternatively, if necessary, the epoxidized isoprene-based rubber can be dissolved at room temperature or at the time of heating by mixing with a solvent of another tertiary amine or a polymer other than the tertiary amine.

Examples of the tertiary amine include pyridines such as pyridine and 2-chloropyridine; α-, β-, and γ-pyridines; lutidines such as 3,5-lutidine and 2,4-lutidine; ethyl. Pyridines; quinolines, isoquinolines, N
-Alkyl imidazoles such as methyl imidizole,
Mention may be made of pyrazine tertiary amines.

Among these tertiary amines, hydrophilic tertiary amines such as those soluble in water or those having high mutual solubility with water are preferable for obtaining a more preferable hydrophilic polymer. That is, when such a tertiary amine is used, the modified polymer is less likely to precipitate during the reaction, and the reaction can be performed in a uniform solution.

Although it is affected by the reaction conditions as well, the tertiary amine having less steric hindrance around the nitrogen atom is more preferable because the nucleophilic attack of the nitrogen atom of the tertiary amine on the epoxiso is advantageous and the reaction is faster and more preferable hydrophilic polymer. Is obtained, which is preferable.

Examples of such hydrophilic tertiary amines having less steric hindrance include pyridines, picolines, lutidines, quinolines, isoquinolines, alkylimidazoles, pyrazines and their derivatives.

Further, the saturated carboxylic acid used in the second step reaction of the present invention may be a compound having one to several carboxy groups, but in order to obtain a more preferable hydrophilic polymer, the number of carbon atoms exemplified below is particularly preferable. Among saturated carboxylic acids of 10 or less, aliphatic saturated acids are preferable, and aliphatic saturated monocarboxylic acids are particularly preferable.

Fatty acids such as formic acid, acetic acid, propionic acid, n-butyric acid, isobutyric acid, valeric acid, caproic acid; glycolic acid, lactic acid, hydroacrylic acid, 3-hydroxybutyric acid, glyceric acid, hydroxy acids such as gluconic acid; fluoroacetic acid, Chloroacetic acid, chloropropionic acid, chlorobutyric acid, trichlorobutyric acid, trichloroacetic acid and other halogeno acids; glyoxalic acid and other aldehyde acids; pyruvic acid, acetoacetic acid, levulinic acid and other keto acids; benzoic acid, p-toluic acid, m- Substituted benzoic acids such as chlorobenzoic acid, salicylic acid, m-hydroxybenzoic acid, p-hydroxybenzoic acid, carboxylic acids having an aromatic ring such as gallic acid, mandelic acid, phenylacetic acid; oxalic acid, malonic acid, succinic acid, tartaric acid, Polybasic acids such as malic acid, phthalic acid, citric acid.

Then, the ring-opening reaction of the epoxy ring of the epoxidized isoprene-based rubber in the second step reaction is carried out as follows.

When the epoxidized isoprene-based rubber is separated from the reaction product solution after the completion of the first-stage reaction, the epoxidized isoprene-based rubber is first dissolved in a tertiary amine or a solvent containing a tertiary amine.

The solvent is not particularly limited, but it is preferable to use the inert organic solvent such as hydrocarbon or halogenated hydrocarbon used in the first step reaction because the process system is not complicated.

When the reaction is performed by using the tertiary amine also as a solvent without using the above solvent, even if the sparingly soluble organic solvent such as methyl alcohol used for separation when the epoxidized isoprene rubber is separated remains, If so, it does not interfere with the ring-opening reaction, and if a small amount of formic acid or hydrogen peroxide remains, it may remain. However, when a large amount of methyl alcohol remains, the reaction temperature does not rise above its boiling point. At that time, most of the methyl alcohol may be distilled off before the reaction.

Next, a carboxylic acid is added to a solution of epoxidized isoprene-based rubber in a solution containing a tertiary amine or a solvent containing a tertiary amine, and the mixture is heated and stirred for reaction. This reaction opens the epoxy ring.

The reaction temperature is preferably 40 ° C or higher and 160 ° C or lower. When the reaction temperature is lower than the above temperature, the reaction rate is slow and there is substantially no reaction. Further, at a temperature higher than the above temperature, the polymer may gel during the reaction.

Also, depending on the reaction time condition, 10 minutes or more 10
It can be done in less than an hour.

When the second-step reaction is carried out without separating the epoxidized isoprene-based rubber from the reaction product solution after the completion of the first-step reaction, the tertiary amine and preferably the first amine are directly added to the reaction product solution.
The same carboxylic acid as that used in the step reaction may be added, and the mixture may be heated and stirred under the same reaction conditions as in the case of separation.

When a hydroxycarboxylic acid is used as the saturated carboxylic acid, some hydroxycarboxylic acids such as gluconic acid and glyceric acid are commercially available as an aqueous solution of 50 to 90% by weight. Since the epoxidized isoprene-based rubber in which a large amount of water is present in the reaction system is not dissolved in the solvent, when using the above hydroxycarboxylic acid aqueous solution, before adding it to the solution of the epoxidized isoprene-based rubber, It is advisable to azeotropically remove water and the tertiary amine to remove water by adding the hydroxycarboxylic acid aqueous solution to a tertiary amine capable of azeotroping with water and heating, or even after the addition. A homogeneous solution of the polymer can be obtained by removing azeotropic water under reduced pressure in the presence of the precipitated polymer.

It is not necessary to react (open) all the epoxy rings of the epoxidized isoprene-based rubber by the second step reaction, and the ring-opening is preferably based on the unsaturated double bond of the isoprene-based rubber before epoxidation. ~ 60 mol%, more preferably 10-45 mol%. That is, for example, when only 5 mol% is epoxidized, it is necessary to open all the rings, but when 60 mol% is epoxidized, all the rings may be opened or epoxidized. The ring opening may be 5 mol% based on the unsaturated double bond of the isoprene-based rubber before the heating.

The residual amount of epoxy ring in the polymer after the second stage reaction is
^It can be estimated by ¹ H-NMR. That is, the polymer is dissolved in heavy water (D ₂ O) solvent [or heavy methanol (CD ₃ OD)] and the ¹ H-NMR
Of the epoxide proton before and after the second step reaction Can be calculated from the amount of decrease.

After the completion of the second-step reaction, the modified polymer (hydrophilic polymer) obtained according to the present invention can be recovered and purified from the reaction solution as follows.

For example, after the second-step reaction is completed, the reaction solution is poured into a large amount of n-hexane, or the solution temperature is lowered to around room temperature, and a poor solvent such as n-hexane is added to the reaction solution. By doing so, the modified polymer is precipitated. At this time, if the concentration of the modified polymer in the reaction liquid is too dilute, the addition of the poor solvent may cause clouding and the polymer may not precipitate. In this case, the reaction solution may be concentrated under reduced pressure to remove a part of the solvent such as tertiary amine, and then the poor solvent may be added to precipitate the polymer.

Next, the modified polymer can be recovered by heating the precipitated and precipitated polymer at room temperature or by heating to distill off the solvent under reduced pressure.

The modified polymer has a high hydrophilicity with a tertiary amine or a saturated carboxylic acid, and depending on the combination of reactions and the reaction rate, it is often impossible to sufficiently remove them by a single precipitation. In such a case, if necessary, the recovered modified polymer is further dissolved in (heat) isopropanol to obtain n.
It can be purified by combining reprecipitation such as precipitation with hexane, whereby a solid modified polymer substantially free of a solvent such as a tertiary amine can be obtained. In addition, there are many fields where it can be used for paints, even if it contains a small amount of solvent.

The modified polymer of the present invention obtained as described above is
After drying, it is a rubber-like polymer, and the degree of hydrophilicity varies depending on the reaction rate of the polymer, the type of tertiary amine used and the type of carboxylic acid, etc. It is soluble in either one at room temperature, and in most tertiary amines such as pyridine at room temperature or when heated, and further n-propanol, isopropanol, isobutyl alcohol, tertiary butyl alcohol, isoamyl alcohol, diethylene glycol, benzyl alcohol. It is also a hydrophilic polymer that dissolves at room temperature or when heated.

However, the above-mentioned hydrophilic polymer according to the present invention is benzene, toluene, xylene, n-hexane (general reagent is n-
Mixture of aliphatic C ₆ hydrocarbons consisting mainly of hexanes often), n-heptane, petroleum ether (mineral spirits), naphtha, aromatic such as cyclohexane, aliphatic,
It is insoluble in alicyclic hydrocarbon compounds, halogenated hydrocarbons such as chloroform and chlorobenzene, and diethyl ether, methyl isobutyl ketone, and acetone. That is, it is insoluble in a solvent having a weak hydrogen bonding property or a medium solvent.

The novel modified polymer obtained by the production method of the present invention is a high molecular weight polymer which is hydrophilic (in some cases, water-soluble) and has an unsaturated double bond in the polymer structure as described above. Application to water-soluble paints, water-absorbent materials, rewetting adhesives, electrodeposition paints, fibers, paper (antistatic,
It can be used in the fields such as water absorption, moisture absorption processing, papermaking sticky agent, etc., and has special characteristics not found in conventional water-soluble polymers (photosensitivity, rubber-like properties, curability by thermal crosslinking). Etc.) can be used.

The effects of the present invention will be described more specifically below with reference to Examples of the present invention together with Comparative Examples.

The microstructure (content of 1,4-bonds) of the isoprene-based rubber used in Examples and Comparative Examples was measured and calculated by infrared absorption spectrum (IR) or nuclear magnetic resonance spectrum (NMR).

The epoxidation rate of the epoxidized isoprene-based rubber (ratio of the total unsaturated double bonds of the isoprene-based rubber before the reaction to be returned to the epoxy structure: mol%) was determined by dissolving the epoxidized isoprene-based rubber in deuterated chloroform. Then, it was calculated by measuring by NMR.

In addition, the structure of the modified polymer obtained by the ring-opening reaction of the epoxy ring shows that this polymer is deuterated methanol (CD ₃ OD).
Alternatively, it was examined by dissolving in heavy water (D ₂ O) and measuring by ¹ H-NMR.

The solubility of polmer was determined by placing about 0.1 g of the polymer in a test tube containing about 5 ml of the solvent and allowing it to stand overnight (about 12 hours).

Example 1 Epoxidation A stirrer, a thermometer, a dropping funnel, and a condenser were provided.
Add 150 ml of toluene to a 300 ml four-necked flask,
Next, KURAPRENE IR-10 (Kuraray Co., Ltd.)
Made, high cis polyisoprene rubber, cis 1,4-bond 98.1
%, 3,4 bond 1.9%, Mooney viscosity ML _{1 + 4} 100 ℃ 90 or more) masticate with a roll and add 13.62 g (0.2mol monomer unit) of polymer whose Mooney viscosity has been reduced to 60 and stir and mix Dissolved.

While maintaining this solution at 45 ° C, 1.85 g (0.04 mol) of formic acid was added and mixed, and then 45.35 g of 30% by weight hydrogen peroxide solution (H ₂ O ₂ was added to the resulting solution at 45 ° C). 0.4 mol) was added dropwise over 20 minutes. The resulting mixed liquid was mixed at 45 ° C. for 5 hours to epoxidize polyisobrene. After the reaction was completed, the reaction product solution was washed with water and the washed reaction product solution was 1000 ml.
Of methanol.

A part of the formed precipitate was taken out for analysis, redissolved in tetrahydrofuran (THF), precipitated in methanol, and then dried under reduced pressure (room temperature, 2 days) to purify epoxidized poiisoprene.

The epoxy reaction rate (the ratio of all double bonds of polyisoprene converted to an epoxy structure before the reaction) determined from NMR was 39 mol%.

Epoxy ring-opening reaction Approximately 7 g of epoxidized polyisoprene (purified, non-dried crude Wet product) precipitated after epoxidation was converted to solid matter and dissolved in 120 ml of pyridine. After adding 6.0 g (0.1 mol), the mixture was reacted for 5 hours. Then, after cooling to room temperature, the polymer was introduced into 500 ml of n-hexane to precipitate the ring-opened polymer.

Redissolved in isopropyl alcohol (IPA) and repeated n-hexane precipitation to purify the modified polyisoprene, which was then dried under reduced pressure at room temperature for 2 days or more to obtain a modified polymer.

(1-1 Acetic acid system) It was confirmed by ¹ H-NMR that the epoxymethine protons had disappeared and the epoxy ring had been opened (80 mol% or more).

The same procedure as in the above example was performed except that 0.1 mol of each of propionic acid, lactic acid, glycolic acid and benzoic acid was used instead of acetic acid in the above example.

The epoxidation rate is around 39 mol%, although there is some variation.

(1-1 Propionic acid-based) (1-3 Lactic acid-based) (1-4 Glycolic acid-based) (1-5 Benzoic acid-based) When the above ring-opened products were examined by ¹ H-NMR, the epoxy ring almost disappeared. Was.

The results are summarized in Table 1.

Example 2 0.07 mol of formic acid and 30% by weight hydrogen peroxide in the epoxidation reaction
Epoxidized polyisoprene having an epoxy reaction rate of 56 mol% was obtained in the same manner as in Example 1 except that 0.6 mol was used for epoxidation.

Using this, an epoxy ring-opening reaction was carried out using various carboxylic acids in the same manner as in Example 1 to obtain a ring-opening polymer.

(2-1 Acetic acid type) (2-2 Lactic acid type) (2-3 Glycolic acid type) When the above ring-opened product was examined by ¹ H-NMR, the epoxy ring was almost disappeared.

The results are summarized in Table 1.

Example 3 0.01 mol of formic acid and 30% by weight hydrogen peroxide in the epoxidation reaction
Epoxidation was performed using 0.1 mol and the same procedure as in Example 1 was carried out to obtain epoxidized polyisoprene having an epoxy reaction rate of 11 mol%.

Using this, an epoxy ring-opening reaction was carried out using various carboxylic acids as in Example 1 to obtain a ring-opening polymer.

(3-1 Acetic acid type) (3-2 Lactic acid type) (3-3 Glycolic acid type) When the above ring-opened product was examined by ¹ H-NMR, the epoxy ring was almost disappeared.

The results are summarized in Table 1.

Comparative Example 1 The raw material used in Examples 1 to 3 (KURAPREN)
E) IR-10 was measured on a polymer which had been masticated to reduce the Mooney viscosity to 60.

The results are summarized in Table 1.

Example 4 Instead of IR, natural rubber (Ribbed smoked sheet, rubber that passes RSS No. 1 was rolled and masticated to give Mooney viscosity ML.
13.2 g of a polymer obtained by dissolving _{1 + 4} 100 ° C.-lowered natural rubber masticated product in 35 toluene and passing it through a 100-mesh wire net and then precipitating with methanol and drying to remove impurities). It carried out like Example 1.

An epoxidized natural rubber having an epoxy reaction rate of 40 mol% was obtained.
Using this, an epoxy ring-opening reaction was carried out in the same manner as in Example 1 to obtain a ring-opening polymer.

(4-1 Acetic acid type) (4-2 Lactic acid type) (4-3 Glycolic acid type) The results are summarized in Table 2.

Comparative Example 2 The NR (Mooney viscosity: 35) solubility of the raw material used in Example 4 is shown.

The results are summarized in Table 2.

Example 5 Kuraprene LIR-50 (average molecular weight v: 47,000, manufactured by Kuraray Isoprene Chemical Co., Ltd.) was used as a raw material polyisoprene.
Epoxidized polyisoprene having an epoxy reaction rate of 34 mol% was obtained in the same manner as in Example 1 except that the melt viscosity was 4,800 poise measured at 38 ° C. with a B type viscometer.

Using this, an epoxy ring-opening reaction was carried out in the same manner as in Example 1 to obtain a ring-opening polymer.

(5-1 Acetic acid type) (5-2 Lactic acid type) (5-3 Glycolic acid type) When the above ring-opened product was examined by ¹ H-NMR, the epoxy ring was almost disappeared.

The results are summarized in Table 2.

Comparative Example 3 The solubility of the raw material Claprene LIR-50 used in Example 5 is shown.

The results are summarized in Table 2.

Comparative Example 1 0.01 mol of formic acid in the epoxidation reaction, 30 wt% hydrogen peroxide solution
Epoxidized natural rubber having an epoxy reaction rate of 3 mol% was obtained in the same manner as in Example 4, except that 0.04 mol was used for epoxidation.

Using this, an epoxy ring-opening reaction was carried out in the same manner as in Example 1 to obtain a ring-opening polymer.

(1-1 Acetic acid type) (1-2 Lactic acid type) The results are summarized in Table 2.

Examples 6 to 7 Lactic acid was used as a carboxylic acid in the epoxy ring-opening reaction at 70 ° C.
Example 1 was repeated except that the reaction was carried out for 2 hours. ^{According to 1} H-NMR, about 50% of the original epoxy ring, that is, about 19 mol% of the total double bonds of the first polyisoprene remained as the epoxy structure, and 20 mol% were ring-opened.

(6 Lactic Acid Ring Opening) The same procedure as in Example 1 was carried out except that lactic acid was used and the reaction was performed at 100 ° C. for 1 hour. ^{According to 1} H-NMR, about 30% of the original epoxy ring, that is, about 12 mol% of the total double bonds of the first polyisoprene remained as an epoxy structure, and about 27 mol% were ring-opened.

(7 Lactic acid ring opening) The results are summarized in Table 3.

Examples 8 to 9 In place of pyridine used in the epoxy ring-opening reaction, α-picoline (Example 8), isoquinoline (Example 9), 120 m each
The same procedure as in Example 1 was carried out except that epoxidized polyisoprene was dissolved in 1 to carry out the ring-opening reaction.

(8-1 Acetic acid type) (8-2 Lactic acid type) (9-1 Acetic acid type) (9-2 Lactic acid type) When the above ring-opened product was examined by ¹ H-NMR, the epoxy ring was almost disappeared. .

The results are summarized in Table 3.

Example 10 Pyridine was used instead of the pyridine used in the epoxy ring-opening reaction.
The same procedure as in Example 1 was performed except that the epoxidized polyisoprene was dissolved in a mixed solution of 75 ml and 75 ml of toluene and the ring-opening reaction was performed at 100 ° C. for 5 hours.

(10-1 Acetic acid type) (10-2 Lactic acid type) The results are summarized in Table 4.

Example 11 Formed from formic acid and hydrogen peroxide as an epoxidizing agent: in-s
In place of itu performic acid, commercially available m-chloroperoxybenzoic acid (manufactured by Aldrich, purity about 80%) was used.
The same procedure as in Example 1 was performed except that 09 mol was used and epoxidized at 30 ° C.

The epoxy reaction rate was 36 mol%.

Using this, an epoxy ring-opening reaction was carried out in the same manner as in Example 1 to obtain a ring-opening polymer.

(11-1 Acetic acid type) (11-2 Lactic acid type) (11-3 Glycolic acid type) The results are summarized in Table 4.

Example 12 Epoxidation A polymer solution was prepared by dissolving 110 ml of toluene in the same manner as in Example 1, and then 12 g of acetic acid was added while keeping the liquid temperature at 70 ° C.
(0.2 mol) was added and mixed. Then in the resulting solution,
22.6 g of 60 wt% hydrogen peroxide solution while maintaining the liquid temperature at 70 ° C
(Containing 0.4 mol of H ₂ O ₂ ) was added dropwise over 20 minutes. The resulting mixed liquid was stirred and mixed at 70 ° C. for 7 hours to epoxidize cis-1,4-polyisoprene.

After completion of the reaction, 150 ml of water was washed with the reaction product solution and allowed to stand to cause phase separation, and water in the lower layer was extracted.

After further washing with 150 ml of water and separating the water, 60 ml of the upper layer toluene solution (there is no apparently cloudy large water droplets),
(About 0.1 mol monomer unit as polymer) was transferred to a four-neck flask with a capacity of 300 ml similar to that used in the epoxidation reaction. (For ring-opening reaction) 200 ml of methyl alcohol was added to the remaining reaction product solution after epoxidation to precipitate and separate the epoxidized polymer for separation. (For analysis) The epoxy reaction rate is 35 mol%.

Ring-opening reaction of epoxy ring Epoxidized polymer solution for ring-opening reaction (toluene solution 60
(120 ml) of pyridine was added to and stirred to homogenize, the temperature was raised to 90 ° C. with stirring, and 6 g (0.1 mol) of acetic acid was added and reacted for 5 hours.

Then, the reaction was carried out in the same manner as in Example 1 except that the mixture was cooled to room temperature and then poured into n-hexane to precipitate and precipitate the modified polymer in which the epoxy ring was opened.

When the above ring-opened product was examined by ¹ H-NMR, the epoxy ring had almost disappeared.

The results are summarized in Table 4.

Example 13 Example 13 was repeated except that oxalic acid was used as the carboxylic acid during the ring-opening reaction of the epoxy ring.

In the ring-opening reaction system, the polymer was deposited 30 minutes after the start of the reaction and became heterogeneous. At this point, the ring-opening reaction was stopped, and the precipitated polymer was purified and dried in the same manner as in Example 1.

When the solubility of the obtained polymer was evaluated, it was water-soluble.

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Claims (3)

[Claims] 1. A polyisoprene or natural rubber having a cis 1,4-bond in which 80% or more of unsaturated double bonds and a molecular weight of 10,000 or more are epoxidized from 5 to 60 mol% of the unsaturated double bonds. , And then one or more tertiary amines selected from the group consisting of pyridines, picolines, lutidines, quinolines, isoquinolines, alkylimidazoles, pyrazines and their derivatives, and saturated carboxylic acids. A method for producing a hydrophilic polymer, which comprises heating to open the epoxy ring in the presence of the hydrophilic polymer. 2. The hydrophilic polymer according to claim 1, wherein the epoxy ring is opened by 5 to 60 mol% based on the unsaturated double bond of polyisoprene or natural rubber before epoxidation. Production method. 3. The method for producing a hydrophilic polymer according to claim 1, wherein the saturated carboxylic acid is a saturated carboxylic acid having a prime number of 10 or less.