WO2022004286A1 - Manufacturing method for polyglycerin, and polyglycerin - Google Patents

Abstract

Provided is a manufacturing method for a polyglycerin with excellent productivity and controlled branch structures. A manufacturing method for a polyglycerin according to the present invention is characterized by reacting a (poly)glycerin and a (poly)glycerin (poly)glycidyl ether. A polyglycerin according to the present invention is characterized by having a weight-average molecular weight of 300-25,000 and a branching degree of 0.1-0.6.

Description

Manufacturing method of polyglycerin and polyglycerin

The present invention relates to a method for producing polyglycerin and polyglycerin.

Polyglycerin is used as a raw material for producing various chemicals such as moisturizers, thickeners, plasticizers, and monomers. The properties of polyglycerin in these applications vary depending on the degree of polymerization and the branched structure. Therefore, it is required to arbitrarily adjust the degree of polymerization and the branched structure according to the purpose of use.

As a conventional method for producing polyglycerin, high-temperature dehydration polymerization of glycerin using an alkali catalyst and ring-opening polymerization reaction of glycidol are industrially common. The polyglycerin produced by the high temperature dehydration condensation method has a degree of polymerization of about 2 to 10 and has a linear structure with few branches. On the other hand, polyglycerin produced by the ring-opening polymerization reaction of glycidol has a degree of polymerization of about 4 to 40 and has a structure with many branches. That is, the high-temperature dehydration condensation reaction has a low molecular weight and low branching, and the ring-opening polymerization reaction of glycidol has a high branching regardless of the molecular weight, and it is difficult to control the molecular weight and the degree of branching at the same time by the conventional production method.

In particular, in order to obtain high molecular weight polyglycerin, either polyglycerin having a linear structure or polyglycerin having a large degree of branching obtained by polymerization of glycidol is used. It is difficult to obtain polyglycerin having a high molecular weight and a controlled degree of branching. Since the properties of polyglycerin change greatly depending on its molecular weight and degree of branching, it is desired to control this to produce various types of polyglycerin that can be applied to many uses.

Patent Document 1 describes a method for producing polyglycerin using glycidol having a hydroxyl group protected with a benzyl group. However, the polyglycerin produced by this method is a substantially linear polyglycerin having an ether bond derived from a hydroxyl group at one end of glycerin and a secondary hydroxyl group at the center, and has a structure with many branches. Polyglycerin cannot be obtained, so it is not a fundamental solution. In addition, structural control of polyglycerin using such a protecting group has problems such as a decrease in productivity and an increase in cost due to an increase in the number of manufacturing processes such as protection and deprotection.

Patent Document 2 describes a method for producing crosslinked polyglycerin by a reaction between polyglycerin and glycerol diglycidyl ether. However, in this method, branched polyglycerin is used as a raw material. Therefore, the obtained polyglycerin depends on the structure of the polyglycerin used as a raw material, the structure of the obtained polyglycerin is limited, and the polyglycerin having an arbitrary degree of branching and molecular weight cannot be obtained.

Patent Document 3 describes highly branched high molecular weight polyglycerin and polyglycidol. However, since this is produced by polymerization of glycidol, it tends to be highly branched, and the degree of branching and the molecular weight cannot be arbitrarily adjusted. In addition, dichloromethane is used as the solvent, which increases the cost for ensuring the environmental load and the safety of the working environment.

Japanese Unexamined Patent Publication No. 09-235246 Japanese Unexamined Patent Publication No. 2018-74048 Japanese Unexamined Patent Publication No. 2010-215734

An object of the present invention is to provide a method for producing polyglycerin, which can produce a wider variety of polyglycerins with high productivity by making the molecular weight and the degree of branching adjustable.

The present inventors have found that polyglycerin can be synthesized while controlling the molecular weight and the degree of branching by reacting (poly) glycerin with (poly) glycerin (poly) glycidyl ether, and have completed the present invention. rice field.
In addition, in this specification, "(poly) glycerin" means "glycerin" and / or "polyglycerin".
Further, in the present specification, "(poly) glycidyl ether" means "glycidyl ether" and / or "polyglycidyl ether".

The present invention is a method for producing polyglycerin, which comprises reacting (poly) glycerin with (poly) glycerin (poly) glycidyl ether.

The (poly) glycerin is preferably a (poly) glycerin having an average degree of polymerization of 1 to 20.
The (poly) glycerin is preferably a linear polyglycerin.

The (poly) glycerin (poly) glycidyl ether is preferably a (poly) glycerin (poly) glycidyl ether having a (poly) glycerin moiety having an average degree of polymerization of 1 to 20.
The (poly) glycerin (poly) glycidyl ether is preferably a (poly) glycerin (poly) glycidyl ether having 1 to 22 glycidyl groups.

The present invention is also a polyglycerin characterized by having a weight average molecular weight of 300 to 25,000 and a degree of branching of 0.1 to 0.6.
The polyglycerin preferably has a dispersity of 3 or more.
The polyglycerin preferably has a primary hydroxyl group / secondary hydroxyl group abundance ratio of 30/70 to 50/50.

The present invention is a method for producing polyglycerin by reacting (poly) glycerin with a (poly) glycerin-based epoxy group, and is characterized in that the molecular weight and the degree of branching can be adjusted without introducing a protecting group into the raw material. And. In particular, polyglycerin having a high molecular weight and having a controlled degree of branching within a suitable range can be preferably obtained.
It is also effective in that a desired polyglycerin can be produced without a decrease in productivity or an increase in cost due to an increase in the number of manufacturing steps such as introduction of a protecting group and an increase in a deprotecting group.

It is a figure which shows an example ^{of the 13} C-NMR spectrum for calculating the degree of branching in the polyglycerin of this invention, and the abundance ratio of a primary hydroxyl group and a secondary hydroxyl group.

The method for producing polyglycerin of the present invention is based on the reaction of (poly) glycerin and (poly) glycerin (poly) glycidyl ether. Further, in the reaction, the reaction proceeds by causing a reaction between the hydroxyl group and the epoxy group. More preferably, it is preferable to select reaction conditions that do not cause the formation of an ether bond due to the hydroxyl group-hydroxyl reaction. This results in one end of the reaction occurring in the epoxy ring of the (poly) glycerin (poly) glycidyl ether. Therefore, the poly obtained by adjusting the degree of polymerization of the (poly) glycerin used, the degree of polymerization of the (poly) glycerin (poly) glycidyl ether, and the degree of introduction of the glycidyl group, and by adjusting the respective blending amounts. It is preferable in that the degree of polymerization and the degree of branching of glycerin can be adjusted.

That is, if a material having a low degree of polymerization of (poly) glycerin is used and the proportion of (poly) glycerin (poly) glycidyl ether used is increased, it becomes easier to obtain polyglycerin having a high degree of branching, and vice versa. Poly) glycerin having a high degree of polymerization is used, and (poly) glycerin (poly) glycidyl ether is used in a low proportion) to obtain polyglycerin having a low degree of branching.

The (poly) glycerin used as a raw material in the present invention is preferably (poly) glycerin having an average degree of polymerization of 1 to 20 calculated from the hydroxyl value, and more preferably 2 to 15 having an average degree of polymerization. To use. As the polyglycerin having an average degree of polymerization in the above range, one having a linear structure can be obtained.

When the (poly) glycerin is a polyglycerin having an average degree of polymerization of 3 or more, it is preferably linear. As described above, it is important to control the degree of branching of the final product polyglycerin in the present invention. Therefore, it is preferable to use a (poly) glycerin having a linear structure in order to control the degree of branching.
In the present invention, the linear structure means a structure in which L13 is 0, or the value of L14 / L13 is 2 or more, and the ratio of D is 5% or less in the following measurement method.

Specific examples of (poly) glycerin include glycerin, diglycerin, triglycerin, tetraglycerin, hexaglycerin, decaglycerin and the like, and commercially available products include glycerin, diglycerin S, R-PG and polyglycerin # 310. , Polyglycerin # 500, Polyglycerin # 750 (all manufactured by Sakamoto Yakuhin Kogyo Co., Ltd.) can be used.

Here, the average degree of polymerization is the average degree of polymerization (n) of polyglycerin calculated from the hydroxyl value by the end group analysis method. Specifically, the average degree of polymerization is calculated from the following equations (Equation 1) and (Equation 2).
(Equation 1) Molecular weight = 74n + 18
(Equation 2) Hydroxyl value = 56110 (n + 2) / molecular weight
The hydroxyl group value in the above (formula 2) is a numerical value that is an index of the number of hydroxyl groups contained in polyglycerin, and contains acetic acid required for acetylating the free hydroxyl group contained in 1 g of polyglycerin. The number of milligrams of potassium hydroxide required for summing. The number of milligrams of potassium hydroxide is calculated according to the editorial of the Japan Oil Chemists'Association, "Established by the Japan Oil Chemists' Society, Standard Oil and Fat Analysis Test Method, 2013 Edition".

The (poly) glycerin (poly) glycidyl ether used as a raw material in the present invention is a compound in which one or more of the hydroxyl groups in the (poly) glycerin are substituted with a glycidyl ether group. In the method for producing polyglycerin of the present invention, the epoxy group in the glycidyl group opens and reacts with a hydroxyl group to obtain a high molecular weight polyglycerin. Then, the degree of branching can be controlled by utilizing the reaction of the epoxy group in the (poly) glycerin (poly) glycidyl ether.

The (poly) glycerin which is the basis of the above (poly) glycerin (poly) glycidyl ether is preferably (poly) glycerin having an average degree of polymerization of 1 to 20 calculated from the hydroxyl value, and more preferably the average degree of polymerization. Use one that is 2 to 15. When the average degree of polymerization is in the above range, it becomes easy to control the reaction with (poly) glycerin.

The (poly) glycerin (poly) glycidyl ether is preferably a linear polyglycerin like the above (poly) glycerin when the repeating unit of the glycerin skeleton is 3 or more. Such a compound obtained by converting (poly) glycerin into (poly) glycidyl ether is preferable in that the structure of the obtained polyglycerin can be suitably controlled.
The term "linear" in (poly) glycerin is the same as the definition of the above-mentioned raw material in (poly) glycerin.

Specific examples of (poly) glycerin (poly) glycidyl ether include glycerin (poly) glycidyl ether, diglycerin (poly) glycidyl ether, tetraglycerin (poly) glycidyl ether, hexaglycerin (poly) glycidyl ether, and decaglycerin (poly). ) Glyceridyl ether and the like, but are not limited thereto. Further, a mixture of two or more of these may be used as a raw material.

The glycidyl group of the (poly) glycerin (poly) glycidyl ether is preferably 1 to 22 on average per molecule. The lower limit of the glycidyl group is more preferably 2, while the upper limit of the glycidyl group is more preferably 8. When the glycidyl group is in the above range, the reactivity is good and the control becomes easy.

The (poly) glycerin (poly) glycidyl ether preferably has an epoxy equivalent of 120 to 200. The lower limit of the epoxy equivalent is more preferably 130, while the upper limit of the epoxy equivalent is more preferably 195. When the epoxy equivalent is in the above range, the polymerization of (poly) glycerin (poly) glycidyl ethers is suppressed, and the polymerization with (poly) glycerin proceeds preferably.

Further, the (poly) glycerin (poly) glycidyl ether may be a mixture of two or more compounds. In particular, when polyglycerin having a low uniformity and a high dispersity is required, those having various degrees of polymerization, the number of glycidyl groups, and the epoxy equivalent may be used in combination.

The (poly) glycerin (poly) glycidyl ether can be easily produced by a conventionally known method. For example, a method of reacting (poly) glycerin with epichlorohydrin in the presence of Lewis acid in a solvent such as toluene and then epoxidizing with an alkali metal hydroxide can be mentioned.

As a combination of the above (poly) glycerin and (poly) glycerin (poly) glycidyl ether, the degree of branching tends to be higher when low molecular weight (poly) glycerin is used, and the degree of branching when high molecular weight (poly) glycerin is used. Tends to be low.
Further, when a low molecular weight (poly) glycerin (poly) glycidyl ether is used, the degree of branching tends to be high, and when a high molecular weight (poly) glycerin (poly) glycidyl ether is used, the degree of branching tends to be low.

In the method for producing polyglycerin of the present invention, the reaction conditions are such that the epoxy group of (poly) glycerin (poly) glycidyl ether opens and reacts with the hydroxyl group of (poly) glycerin to form polyglycerin. Is preferable. That is, as a side reaction, it is more preferable that the reaction conditions do not cause a reaction such that an ether bond is formed by the reaction between the hydroxyl groups. This is because when a branch based on such a reaction is generated, it becomes difficult to control the structure of polyglycerin, which is a product which is the object of the present invention.

The blending ratio of the above (poly) glycerin and (poly) glycerin (poly) glycidyl ether may be appropriately set, and for example, (poly) glycerin (poly) glycerin (poly) glycerin, which is 0.05 to 2 times by weight as much as (poly) glycerin. It is preferable to react with poly) glycidyl ether.

As the catalyst used in the present invention, an acid catalyst and an alkaline catalyst can be used, but an alkaline catalyst is preferable from the viewpoint of suppressing side reactions, and alkali metal water such as sodium hydroxide, potassium hydroxide and cesium hydroxide is preferable. It is more preferable to use an oxide. The amount of these alkali metal hydroxides used is preferably 0.1 to 0.5 wt% with respect to the total amount of (poly) glycerin and (poly) glycerin (poly) glycidyl ether.

The reaction temperature of (poly) glycerin and (poly) glycerin (poly) glycidyl ether is preferably 120 ° C to 180 ° C, more preferably 140 ° C to 160 ° C. If the temperature is lower than 120 ° C, the reaction rate may be significantly slowed down, and if the temperature exceeds 180 ° C, the product may be colored, an odor may be generated, and problems such as an etherification reaction between hydroxyl groups, which is a side reaction, may proceed. There is.

The reaction between (poly) glycerin and (poly) glycerin (poly) glycidyl ether in the production method of the present invention is possible even in the absence of a solvent. Therefore, the production method of the present invention is useful in that it is excellent in safety, can easily produce polyglycerin, and has no environmental load.

Further, the reaction between (poly) glycerin and (poly) glycerin (poly) glycidyl ether may be carried out in the presence of 5 to 20 wt% aprotic polar solvent, if necessary. The aprotonic polar solvent is not particularly limited, but polyethylene glycol alkyl ether is preferable, and specific examples thereof include diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, pentaethylene glycol dimethyl ether, and diethylene glycol diethyl ether. Examples thereof include triethylene glycol diethyl ether, tetraethylene glycol diethyl ether, and pentaethylene glycol diethyl ether. Of these, diethylene glycol dimethyl ether and triethylene glycol dimethyl ether are more preferable from the viewpoints that the boiling point is equal to or higher than the reaction temperature and the distillation is easy after polymerization.

In reacting (poly) glycerin with (poly) glycerin (poly) glycidyl ether, a method of adding (poly) glycerin (poly) glycidyl ether to (poly) glycerin and reacting the two is preferable.
The addition of (poly) glycerin (poly) glycidyl ether is preferably a method of gradually dropping the ether, and the dropping rate is preferably defined as the rate at which the entire amount is dropped in 30 to 60 minutes. In particular, when the solution is dropped faster than 30 minutes, a large amount of unreacted glycidyl ether remains in the reaction system, and the reaction between the glycidyl ethers tends to occur. Further, it is preferable to continue the reaction in 5 hours or more and 10 hours or less, preferably 6 hours or more and 8 hours or less after the completion of the dropping. If it is less than 5 hours, epoxy groups tend to remain in the polyglycerin skeleton, and if it exceeds 10 hours, the product may be colored and problems such as odor may occur.

The obtained polyglycerin can be purified by further reducing the pressure or blowing saturated heated steam to distill off low molecular weight compounds, or by treating with activated carbon, ion exchange resin, adsorbent, etc. by reprecipitation or the like. good.
The polyglycerin of the present invention may contain a chlorine component derived from the raw material used. Further, if necessary, the chlorine component may be removed by purification or the like.

The present invention also relates to polyglycerin having a specific structure. Such a chemical structure is a structure that can be obtained by the method for producing polyglycerin of the present invention.

The polyglycerin of the present invention preferably has a weight average molecular weight (Mw) in the range of 300 to 25,000. The lower limit is more preferably 500, further preferably 1,000, particularly preferably 1,300, and most preferably 3,600. The upper limit is more preferably 22,000 and even more preferably 20,000. If the upper limit of the weight average molecular weight is in the above range, the handleability is excellent. Further, if the lower limit is within the above range, polyglycerin having a high degree of dispersion can be obtained.

Further, the degree of dispersion (Mw / Mn) is preferably 3 to 90. Especially in the interfacial interaction, when the average molecular weights are the same, those with a high degree of dispersion (wide molecular weight distribution) are more likely to obtain the molecular weight effect in interfacial adsorption than those with monodisperse (narrow molecular weight distribution). , It is considered that the interfacial interaction is enhanced.

In the manufacturing method of the present invention, the degree of dispersion can also be controlled. That is, both polyglycerin having a wide molecular weight distribution and polyglycerin having a narrow molecular weight distribution can be appropriately produced according to the purpose. Further, in the production method of the present invention, it is possible to produce polyglycerin having a dispersity that could not be produced in the past.

The weight average molecular weight (Mw) and the number average molecular weight (Mn) are values measured by GFC analysis using polyethylene glycol / polyethylene oxide as a standard sample under the following equipment and conditions.
Separation column: SB-806M (8 mm x 30 mm, Shodex)
Column temperature: 40 ° C
Mobile phase solvent: Ion-exchanged water
Mobile phase flow rate: 1.0 mL / min
Sample concentration: 0.5 wt%
Injection volume: 50 μL
Detector: RI detector (Waters2414, Waters)

Further, the polyglycerin of the present invention preferably has a branching degree (DB) in the range of 0.1 to 0.6 in consideration of the difficulty of production.

The method for producing polyglycerin of the present invention can also control the degree of branching. Even if the molecular weight is high as described above, it is also preferable that a product having a controlled degree of branching can be preferably obtained. Since the degree of branching affects the physical properties such as the polarity and viscosity of polyglycerin, it is preferable in that it can be controlled within the above-mentioned specific range only by selecting the raw material to be used.

The lower limit of the degree of branching is more preferably 0.15 and even more preferably 0.2. The upper limit of the degree of branching is more preferably 0.55, further preferably 0.4.
The higher the degree of branching, the higher the hydrophilicity, and when the degree of branching is within the above range, a highly hydrophilic product can be obtained even if the molecular weight is small.

In the production method of the present invention, polyglycerin having a high weight average molecular weight can be obtained while controlling the degree of branching, the weight average molecular weight is 300 to 25,000, and the degree of branching is 0.1 to 0.6. The weight average molecular weight is preferably 3,600 to 25,000, and the branching degree is more preferably 0.15 to 0.4.

The degree of branching is ^{a value calculated by 13} C-NMR according to the following equipment and conditions.
Measurement conditions: Polyglycerin is dissolved in deuterated methanol so as to be 10 wt%.
Equipment used: 175MHz 13C-NMR (Bruker AVANCE700)
Measurement conditions: Quantitative measurement mode, pulse interval 10 seconds

^{The structural analysis of polyglycerin by 13} C-NMR described in detail below was performed based on the method described in "Controlled Synthesis of Hyperbranched polyglycerols by Ring-Opening Multibranching Polymerization" Macromoleculers 1990, 32, 4240-4246. ..

Glycerin present in polyglycerin can be classified into the following five structures according to the bonding mode of the hydroxyl group and the ether bond.

When a ¹³ C-NMR measurement of polyglycerin is performed, carbon is divided into several peaks based on its chemical environment. An example of such ¹³ C-NMR measurement results is shown in FIG. The peaks are observed as eight peaks A to H. Then, each of these peaks has been identified in the carbon at a specific position in each of the above-mentioned L13, D, L14, T1 and T2 structures.
Therefore, the amount of each structure of L13, D, L14, T1 and T2 can be calculated based on the integral ratio at each peak.

Specifically, the abundance ratio of each structure of L13, D, L14, T1 and T2 represented by the above general formula can be calculated by using the integral ratio of each peak (IntA or the like) and the following formula. ..
L13 = IntB
D = IntC
L14 = (IntD / 2 + IntF-L13) / 2
T1 = (IntG + (IntE-2D) / 2) / 2
T2 = (IntG + (IntE-2D) / 2) / 2

The degree of branching (DB) is calculated by the following formula from the abundance ratios of D, L13, and L14.
Branch degree (DB) = 2D / (2D + L13 + L14)

The polyglycerin of the present invention preferably has a primary hydroxyl group to a secondary hydroxyl group abundance ratio of 30/70 to 50/50. Further, it is more preferably 30/70 to 45/55.
As described above, in the case of polyglycerin having a relatively large number of secondary hydroxyl groups, it is presumed that the ability to capture metal ions is particularly high due to the secondary hydroxyl groups existing inside the polyglycerin.
Further, the production method of the present invention is also preferable in that the above ratio can be appropriately controlled.

The abundance ratio of the primary hydroxyl group and the secondary hydroxyl group is the abundance ratio of ^{L13, L14, D, T1 and T2 calculated in the above 13} C-NMR spectrum, and the abundance ratios of the primary hydroxyl group and the secondary hydroxyl group bonded to each. It is a value calculated from a number.
The number of primary hydroxyl groups and secondary hydroxyl groups in each of the above structural units is as shown in Table 1.

With reference to Table 1 above, the abundance ratio of each hydroxyl group can be calculated by adding the value obtained by multiplying the abundance ratio of each structure in polyglycerin by the number of each hydroxyl group.
Primary hydroxyl group: (L13 × 1) + (T1 × 1) + (T2 × 2)
Secondary hydroxyl group: (L14 × 1) + (T1 × 1)
The ratio of the ratio of the primary hydroxyl group to the secondary hydroxyl group obtained by the above formula is converted into a percentage and used as the abundance ratio of the primary hydroxyl group and the secondary hydroxyl group.

The obtained polyglycerin can be used as a dispersant / resin raw material for various purposes. Further, for example, acrylic esterification, epoxidation, urethanization, allyl etherification, alkoxysilylation and the like can be performed by the reaction of hydroxyl groups, and these can be used as a resin raw material. Further, for example, use as a dispersant in fine particles of a metal oxide or the like can be mentioned.

The polyglycerin of the present invention can convert a part of the hydroxyl group into an epoxy group by a known method.
The polyglycerin of the present invention can also be acrylic esterified by reacting a part of the hydroxyl group with (meth) acrylic acid or a derivative thereof by a known method.
The polyglycerin of the present invention can also be urinated by reacting a part of the hydroxyl group with an isocyanate compound by a known method.
The polyglycerin of the present invention can also be converted to allyl ether by reacting a part of the hydroxyl group with an allyl compound by a known method.
The polyglycerin of the present invention can also be alkoxysilylated by reacting a part of the hydroxyl group with an isocyanate compound having an alkoxysilyl at the end, an epoxy compound, or the like by a known method. Further, alkoxysilylation may be performed by a hydrosylation reaction with allyl ether.

By using each of the derivatives thus obtained as a part or all of the raw materials for resin synthesis, a resin having a polyglycerin skeleton can be obtained.
Further, as described above, in the method for producing polyglycerin of the present invention, the structure thereof can be variously changed by adjusting the raw materials used and the blending ratio. Therefore, it is preferable in that a polyglycerin skeleton having the physical characteristics required for the application can be easily obtained.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

<Example 1>
Glycerin (manufactured by Sakamoto Yakuhin Kogyo Co., Ltd.) was previously dehydrated at 120 ° C. and 5 mmHg or less for 2 hours to remove water in the reaction system. 30.00 g of dehydrated glycerin and 0.15 g of sodium hydroxide were placed in a 100 mL eggplant flask equipped with a gym funnel, a temperature sensor, a nitrogen tube and a magnetic induction stirrer, and the temperature was raised to 140 ° C. Then, 46.26 g of SR-GLG (epoxy equivalent 142, viscosity 170 mPa · s, manufactured by Sakamoto Yakuhin Kogyo Co., Ltd.) was added dropwise as (poly) glycerin (poly) glycidyl ether over 30 minutes. After reacting at 140 ° C. for 7 hours, 40 mL of ion-exchanged water was added and the mixture was stirred at 90 ° C. for 2 hours, and an acidic ion-exchange resin was added and stirred for 2 hours. The ion exchange resin was separated by filtration, and the obtained filtrate was concentrated to obtain polyglycerin.
Each evaluation of the obtained polyglycerin was performed by the above measurement / calculation method.

<Example 2>
39.00 g of diglycerin (manufactured by Sakamoto Pharmaceutical Co., Ltd.) was used as (poly) glycerin, 40.03 g of SR-GLG was used as (poly) glycerin (poly) glycidyl ether, and 0.20 g of sodium hydroxide was used as a catalyst. Except for this, the reaction was carried out under the same conditions as in Example 1.

<Example 3>
58.50 g of polyglycerin # 500 (average polymerization degree 6, manufactured by Sakamoto Yakuhin Kogyo Co., Ltd.) as (poly) glycerin, SR-4GL (epoxy equivalent 170, viscosity 1700 mPa · s) as (poly) glycerin (poly) glycidyl ether The reaction was carried out under the same conditions as in Example 1 except that 18.07 g of Sakamoto Yakuhin Kogyo Co., Ltd. was used and 0.29 g of sodium hydroxide was used as a catalyst.

<Example 4>
55.01 g of polyglycerin # 500 as (poly) glycerin, 17.00 g of SR-GLG as (poly) glycerin (poly) glycidyl ether, 0.28 g of sodium hydroxide as a catalyst, and 4.46 g of diethylene glycol dimethyl ether as a solvent. The reaction was carried out under the same conditions as in Example 1 except that it was used.

<Example 5>
58.50 g of polyglycerin # 500 as (poly) glycerin, 18.25 g of SR-DGE (epoxy equivalent 162, viscosity 650 mPa · s, manufactured by Sakamoto Yakuhin Kogyo Co., Ltd.) as (poly) glycerin (poly) glycidyl ether, The reaction was carried out under the same conditions as in Example 1 except that 0.29 g of sodium hydroxide was used as a catalyst.

<Comparative Example 1>
700 g of glycerin and 5.25 g of sodium hydroxide were placed in a 1 L eggplant flask equipped with a temperature sensor, a nitrogen tube and a stirrer. The polycondensation reaction was carried out at 260 ° C. to obtain polyglycerin having a hydroxyl value of 960.

<Comparative Example 2>
9.40 g of dehydrated glycerin and 0.075 g of 85 wt% phosphoric acid were placed in a 100 mL eggplant flask equipped with a gym funnel, a temperature sensor, a nitrogen tube and a magnetic induction stirrer, and the temperature was raised to 120 ° C. 66.60 g of glycidol was added dropwise over 10 hours using a syringe pump, and the reaction was further carried out for another 2 hours after the addition was completed. 30 mL of ion-exchanged water was added and the mixture was stirred at 90 ° C. for 2 hours, and an acidic ion-exchange resin was added and stirred for 2 hours. The ion exchange resin was separated by filtration, and the obtained filtrate was concentrated to obtain polyglycerin.

<Comparative Example 3>
The same procedure as in Comparative Example 2 was carried out except that 2.00 g of glycerin, 0.055 g of 85 wt% phosphoric acid and 62.75 g of glycidol were used to obtain polyglycerin.

<Evaluation>
The contact angle was measured by the following method. For each polyglycerin, a 10 mass% aqueous solution was prepared with ion-exchanged water. In addition, slide glass (manufactured by Matsunami Glass) was used as the base material. These were measured after standing at 23 ° C./50% RH for one day. Using a surface tension meter Drop Master 500 (manufactured by Kyowa Interface Science), 1 μL of a polyglycerin aqueous solution was dropped onto a slide glass, and the contact angle after standing for 1 minute from the drop was determined using θ / 2.
It can be evaluated that when the contact angle is 30 ° or less, the wettability is excellent and the hydrophilicity of the solid surface is improved.

Table 2 shows the evaluation results of Examples 1 to 5 and Comparative Examples 1 to 3.

From the results in Table 2, in Examples 1 to 5, polyglycerin having a significantly different molecular weight can be obtained by changing the raw materials, and at the same time, polyglycerin having various branching degrees can be obtained. It can be seen that the production method of the present invention makes it possible to separately produce polyglycerins having different molecular weights and degree of branching.

The method for producing polyglycerin of the present invention is preferable in that polyglycerin having a controlled molecular weight and degree of branching can be produced by a simple method.

Claims (8)

1. A method for producing polyglycerin, which comprises reacting (poly) glycerin with (poly) glycerin (poly) glycidyl ether.
2. The method for producing polyglycerin according to claim 1, wherein the (poly) glycerin is (poly) glycerin having an average degree of polymerization of 1 to 20.
3. The method for producing polyglycerin according to claim 1 or 2, wherein the (poly) glycerin is a linear polyglycerin.
4. The polyglycerin according to any one of claims 1 to 3, wherein the (poly) glycerin (poly) glycidyl ether is a (poly) glycerin (poly) glycidyl ether having a (poly) glycerin moiety having an average degree of polymerization of 1 to 20. Manufacturing method.
5. The method for producing polyglycerin according to any one of claims 1 to 4, wherein the (poly) glycerin (poly) glycidyl ether is a (poly) glycerin (poly) glycidyl ether having 1 to 22 glycidyl groups.
6. A polyglycerin having a weight average molecular weight of 300 to 25,000 and a degree of branching of 0.1 to 0.6.
7. The polyglycerin according to claim 6, wherein the degree of dispersion is 3 or more.
8. The polyglycerin according to claim 6 or 7, wherein the abundance ratio of the primary hydroxyl group / secondary hydroxyl group is 30/70 to 50/50.

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