JPH11269129A - Production of polyol (meth)acrylate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a polyol (meth)acrylate having a specific number of (meth)acryloyl groups. SOLUTION: This method for producing a polyol (meth)acrylate comprises a synthetic step for carrying out an esterifying reaction of (meth)acrylic acid with a polyol and providing a mixture of plural polyol (meth)acrylates different in number of (meth)acryloyl groups and a purifying step for treating the resultant mixture with a supercritical fluid and thereby separating the polyol (meth) acrylate having a specific number of the (meth)acrylol groups from other polyol (meth)acrylates. The treatment is preferably conducted by an extraction with the supercritical fluid or a chromatographic separation using the supercritical fluid as an eluate. The supercritical fluid preferably comprises a mixture of CO2 with a lower alcohol.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a polyol (meth) acrylate, and more particularly, to a polyol (meth) having a specific (meth) acryloyl group number.
The present invention relates to a method for producing a polyol (meth) acrylate capable of obtaining an acrylate with high purity.

[0002]

2. Description of the Related Art Polyol (meth) acrylates are used as active energy ray-curable inks, paints and adhesives.
It is also useful as a modifier for various resins. This polyol (meth) acrylate has different properties such as strength, elongation, and abrasion resistance of the resin after curing or polymerization due to the difference in the number of (meth) acryloyl groups in one molecule. This polyol (meth) acrylate is usually
It is produced by subjecting (meth) acrylic acid and polyol to an esterification reaction.

[0003]

However, what is produced by this reaction is a mixture of a plurality of polyols (meth) acrylates having different numbers of (meth) acryloyl groups, and a polyol having a specific number of (meth) acryloyl groups ( It is not possible to produce only meth) acrylate (hereinafter also referred to as “specific (meth) acrylate”). Further, there is a limit in increasing the ratio of the specific (meth) acrylate by adjusting the reaction conditions and the like. It is also conceivable to increase the purity of the specific (meth) acrylate by purifying the product of the esterification reaction. However, in a purification method usually used industrially, for example, distillation, a specific (meth) acrylate and another polyol (meth) acrylate having a different number of (meth) acryloyl groups (hereinafter, referred to as “other (meth) acrylate”). Also called.)
It is difficult to separate them from each other because of a small difference in boiling point between them.

Conventional methods for separating compounds having such a similar structure include capillary gas chromatography (capillary GC), gel permeation chromatography (GPC), and high performance liquid chromatography (HPLC). But Capillary GC
Although is excellent in separation performance, it can not be used for purification of a specific (meth) acrylate on an industrial scale because the amount of sample that can be processed is extremely small and the sample cannot be collected. In addition, GPC has insufficient separation performance between a specific (meth) acrylate and another (meth) acrylate.
Further, when HPLC is applied to the polyol (meth) acrylate which is the production object of the present invention, an aqueous eluent should be selected depending on the polarity of the test sample, but there is a possibility that the (meth) acrylate is hydrolyzed. It is inappropriate because of this.

[0005] For the above reasons, the polyol (meth) acrylate conventionally commercially available is a specific (meth) acrylate.
A mixture containing acrylate as a main component but also containing other (meth) acrylate. For example, what is commercially available as "pentaerythritol tri (meth) acrylate" is actually a mixture containing di- or tetra-substituted (meth) acrylate. For this reason,
When the content and the composition ratio of the (meth) acrylate other than the trisubstituted compound fluctuate, the performance of the cured product or the polymer becomes unstable. When a (meth) acrylate having one hydroxyl group, for example, pentaerythritol tri (meth) acrylate (hereinafter referred to as “PETA”) as described above is used as a raw material for producing urethane (meth) acrylate. As described above, since commercially available PETA contains components such as pentaerythritol di (meth) acrylate having two hydroxyl groups, the reaction mixture obtained by reacting commercially available PETA with isocyanate has a viscosity May rise, making it difficult to handle. If it is possible to produce a high-purity specific (meth) acrylate relatively efficiently, the use of this specific (meth) acrylate is expected to further expand.

An object of the present invention is to provide a method for producing a polyol (meth) acrylate capable of obtaining a polyol (meth) acrylate having a specific (meth) acryloyl group number with high purity.

[0007]

Means for Solving the Problems The present inventors treat a mixture obtained by an esterification reaction with a supercritical fluid, thereby enriching a specific (meth) acrylate of the mixture to specify a high purity (meth) acrylate. The present invention has been completed by finding that a (meth) acrylate can be produced.

The method for producing a polyol (meth) acrylate according to the first aspect of the present invention is a method for producing a polyol (meth) acrylate having a different number of (meth) acryloyl groups by subjecting (meth) acrylic acid to an esterification reaction with the polyol. A synthesis step of obtaining a mixture comprising: and a polyol (meth) having a specific (meth) acryloyl group number by treating the mixture with a supercritical fluid.
And a purification step of separating the acrylate from other polyol (meth) acrylates.

The method for producing a polyol (meth) acrylate according to the second aspect of the present invention is the method according to the first aspect, wherein
The process using the supercritical fluid is at least one type of process selected from extraction using a supercritical fluid and column chromatography using the supercritical fluid as an eluent.

As the supercritical fluid, a fluid composed of CO ₂ is preferably used as in the third invention, and a fluid composed of a mixture of CO ₂ and a lower alcohol is more preferably used as in the fourth invention. .

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
In the present specification, acrylic acid and / or methacrylic acid are referred to as (meth) acrylic acid, acrylate and / or methacrylate are referred to as (meth) acrylate, and acryloyl and / or methacryloyl groups are referred to as (meth) acryloyl groups. .

(1) Polyol The polyol (meth) acrylate produced by the method of the present invention is an esterified product of (meth) acrylic acid and a polyol. This “polyol” may be difunctional or trifunctional, or may be a polyfunctional polyol having four or more functional groups. Specific bifunctional polyols include ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, nonanediol,
Neopentyl glycol, cyclohexanediol, cyclohexane dimethanol, bisphenol A, bisphenol F, bisphenol S, and alkyl group-substituted products thereof are exemplified. Also, as a trifunctional polyol,
Trimethylolpropane, trimethylolethane, glycerin, trihydroxyethyl isocyanurate (TH
EIC) and its alkyl group-substituted products. Examples of tetrafunctional or higher polyols include pentaerythritol, ditrimethylolpropane, dipentaerythritol, diglycerin, and alkyl group-substituted products thereof.

Further, a polyol obtained by adding an alkylene oxide to the above polyol may be used. As the alkylene oxide, ethylene oxide, propylene oxide, butylene oxide and the like can be used. Among them, it is preferable to use ethylene oxide or propylene oxide. The added mole number of the alkylene oxide is preferably 1 to 10 moles, and more preferably 1 to 5 moles.

(2) Esterification Reaction The esterification reaction between the polyol and (meth) acrylic acid may be performed according to a conventionally known method. For example,
A method of heating and stirring (meth) acrylic acid and a polyol in the presence of a catalyst may be used. In this case, since the reaction is a dehydration reaction, it is preferable to carry out the reaction by distilling water from the reaction system. For example, using a solvent that is not completely mixed with water, such as benzene, toluene, xylene, ethyl acetate, butyl acetate, and / or methyl isobutyl ketone, water produced in the reaction is azeotroped with the solvent to leave the reaction system. It is preferable to carry out the reaction while distilling off. The amount of the solvent used in this case is preferably such that the concentration of the obtained polyol (meth) acrylate mixture becomes 20 to 80% by weight.

As a catalyst for the esterification reaction, an acidic catalyst such as sulfuric acid, methanesulfonic acid or p-toluenesulfonic acid is used. The preferred amount of the catalyst is 0.1 to
5% by weight. The reaction temperature may be appropriately determined depending on the boiling point of the solvent to be used and the like.
It is preferably set to ° C. In this reaction, it is preferable to add a polymerization inhibitor such as hydroquinone or hydroquinone monomethyl ether, or to blow in molecular oxygen in order to stably perform the reaction. When using a polymerization inhibitor, 10 wtppm to 2 wt% based on the reaction solution.
% Is preferably used.

(3) Treatment with Supercritical Fluid In the production method of the present invention, the mixture of polyol (meth) acrylate obtained by the esterification reaction is treated with a supercritical fluid, so that the mixture is purified and highly purified. A specific (meth) acrylate of purity is obtained. Examples of the "treatment" include extraction with a supercritical fluid, column chromatography separation using the supercritical fluid as an eluent (hereinafter, referred to as "supercritical fluid chromatography" or "SFC"). Further, these processes may be performed in combination.

As the supercritical fluid used in the above treatment, a fluid capable of separating a specific (meth) acrylate from another (meth) acrylate may be appropriately selected and used. For example, a fluid composed of one or more compounds selected from carbon dioxide, ethane, toluene and the like can be used. Note that the composition of the supercritical fluid may be changed gradually or stepwise during the above processing. This makes it possible to adjust the polarity and the like of the supercritical fluid and sequentially separate polyol (meth) acrylates having different numbers of (meth) acryloyl groups.

In the present invention, a supercritical fluid composed of carbon dioxide is preferably used. This is because the carbon dioxide is easily removed from the target substance after the above treatment, does not leave any impurities after being removed, and is easy to handle. Further, it is more preferable to use a supercritical fluid composed of carbon dioxide and a lower alcohol. Examples of the “lower alcohol” include an alkyl alcohol having 1 to 4 carbon atoms, and methyl alcohol and ethyl alcohol are particularly preferably used. The mixing ratio of carbon dioxide and lower alcohol in the supercritical fluid is 10 carbon dioxide.
It is preferable that the lower alcohol is 1 to 50% by volume relative to 0% by volume.

In order to bring the fluid into a supercritical state, the temperature and pressure may be set according to the fluid used. For example, when CO ₂ is used as the fluid, the temperature and pressure exceeding critical conditions of a temperature of 31 ° C. and a pressure of 72.9 atm may be appropriately set according to the specific (meth) acrylate to be separated.

Various methods are employed for supercritical fluid chromatography. For example, a mixture of a mixture containing a specific (meth) acrylate and a supercritical fluid is introduced into a column, and the separated mixture separated from the column is confirmed at each time by an ultraviolet absorption spectrum or the like, and the specific (meth)
A method of separating into a fraction of an acrylate and other components is exemplified. The type, length, diameter, etc. of the column to be used may be appropriately selected depending on the specific (meth) acrylate to be used and the fluid to be used. In addition, conditions such as temperature and pressure in the column may be appropriately selected according to the target specific (meth) acrylate and the fluid to be used. Generally, in the latter half of the treatment, it is preferable to lower the column temperature and / or increase the column pressure in order to drive out components other than the specific (meth) acrylate from the column.

Various methods are employed for the extraction treatment with the supercritical fluid. For example, there is a method of injecting a mixture containing a specific (meth) acrylate into an extractor, and bringing the mixture into contact with a specific type of supercritical fluid to perform extraction. The specific (meth) acrylate in the extract is separated from the fluid by lowering the temperature and pressure. As a method for changing the components to be extracted, as described above, CO 2
A method of adjusting the mixing ratio of ₂ and alcohol to change the polarity of the fluid, and the like.

According to the method of the present invention, it is possible to produce a polyol (meth) acrylate having a very high purity (for example, 70% or more) of the specific (meth) acrylate.
Further, according to the method of the present invention, 70% of the specific (meth) acrylate synthesized by the esterification reaction (that is, the specific (meth) acrylate contained in the mixture).
By weight or more (more preferably 80% by weight or more, more preferably 90% by weight or more) can be recovered with high purity as described above.

[0023]

The present invention will be described more specifically with reference to the following examples.

(Example 1) Example 1 is an example in which pentaerythritol triacrylate and pentaerythritol tetraacrylate were produced by using the method of the present invention.

(1) Synthesis of Polyol Acrylate 68 g of pentaerythritol (500 mmo) was placed in a 500 ml reactor equipped with a reflux condenser and a water content receiver.
l), acrylic acid 108 g (1,500 mmol), toluene 180 g, p-toluenesulfonic acid monohydrate
8 g (20 mmol) and 0.05 g of methylhydroquinone as a polymerization inhibitor were charged. Then, the reactor was heated to a toluene reflux atmosphere, and the esterification reaction was allowed to proceed while distilling off water produced as a result of the esterification reaction. Further, in order to prevent polymerization of acrylic acid, the reaction was performed while blowing air into the reaction solution. After the above conditions were continued until no water distilled out, the reaction was terminated by cooling the system. The obtained reaction solution was washed with a 5% aqueous NaOH solution, and an organic layer was extracted with toluene. The organic layer was washed with water to make a neutral atmosphere. Furthermore, after dehydrating the organic layer with sodium sulfate, the solvent was removed under reduced pressure, followed by filtration to obtain 138 g of a polyol acrylate mixture.

(2) Analysis of Polyol Acrylate Mixture The mixture obtained in the above (1) was dissolved in acetone to prepare a concentration of 100 mg / ml. For this solution,
The composition was analyzed by capillary GC under the following conditions.
Table 1 shows the composition ratio determined from the area ratio of each peak. Table 1
As can be seen, this mixture contains 11.9% pentaerythritol diacrylate (ie, disubstituted), 55.9% pentaerythritol triacrylate (ie, trisubstituted), and pentaerythritol tetraacrylate (ie, tetrasubstituted). ) 24.2%.

<Capillary GC conditions> Apparatus: "HP5890" (trade name, manufactured by Yokogawa Hewlett-Packard Co., Ltd.) Type and shape of column: Ultraalloy, 15m × 0.5
mm Inlet and detector temperature: 350 ° C Column temperature: 130 ° C to 3 at a rate of 10 ° C / min
Heat up to 20 ° C. Carrier gas and flow rate: He 40 kpa, SP ratio
About 1:50 Sample injection volume: 1 μl

(3) Purification of Polyol Acrylate In this example, tri- and tetra-substituted acrylates among the acrylates contained in the above mixture were defined as “specific acrylates” and were subjected to supercritical fluid chromatography under the following conditions. Purification was performed. As a sample for SFC, the above mixture was used as a 500 mg / ml CH ₂ Cl ₂ solution.

<SFC Condition 1> Apparatus: "Jasco S" manufactured by JASCO Corporation
UPER-201 ”Column type and shape: superpack SIL, 1
0 mmφ × 250 mm Eluent and its flow rate: CO ₂ 5.0 ml / min EtOH 0.5 ml / min Pressure: initial 20 MPa, 2 after 30 minutes from sample injection
5 Mpa temperature: The temperature is lowered from 120 ° C. to 90 ° C. at a temperature lowering rate of 1 ° C./min. 40 ° C after 30 minutes from the sample injection Sample injection volume: 500 μl (sample loading 250 mg)

FIG. 1 shows a chromatogram obtained by performing simultaneous multi-wavelength measurement using a photodiode array detector in this SFC. The upper part of FIG. 1 is a contour plot with the retention time on the horizontal axis and the wavelength on the vertical axis. The maximum absorption chromatogram (normal chromatogram) in which the maximum absorption portion in this contour plot is projected on the horizontal axis is shown in the lower part. The fractions for the periods (F1 and F2) indicated below the chromatogram were respectively collected.

The structures of these fractions F1 and F2 were identified by ¹ H-NMR. A ¹ H-NMR chart of fraction F1 in FIG. 2 (a), a ¹ H-NMR chart of the fraction F2 in FIG. 2 (b). ¹
H-NMR assignment results are also shown in FIGS. 2 (a) and 2 (b). From the chemical shift, it is possible to distinguish whether the methylene proton of pentaerythritol is an alcohol or an ester. Focusing on these signals, it was confirmed that the fraction F1 in which the signal e attributed to the methylene group of the alcohol was not observed was a tetra-substituted product. On the other hand, F2 has a signal e.
Was observed, and the integration ratio with the signal d attributed to the methylene group of the ester form was about 1: 3, confirming that the tri-substituted form was the main component. From this result, it is understood that the fraction F1 is composed of a tetrasubstituted product and the fraction F2 is composed of a trisubstituted product. These fractions were quantitatively analyzed by capillary GC under the conditions described in (2) above. Table 1 shows the composition ratio of each fraction obtained from the area ratio of each peak.

[0032]

[Table 1]

As can be seen from Table 1, fraction F1 is composed of pentaerythritol tetraacrylate having a purity of 90% or more, and fraction F2 is composed of pentaerythritol triacrylate having a purity of 90% or more. That is, each of these specific acrylates could be concentrated to a purity of 90% or more by SFC. Further, 90% by weight or more of each specific acrylate contained in the mixture could be recovered in such a high purity.

(Embodiment 2) This embodiment is an example in which the SFC conditions are changed in the manufacturing method of Embodiment 1. As in Example 1, the tri- and tetra-substituted acrylates of pentaerythritol were designated as “specific acrylates”. Also,
The SFC conditions were as shown below, and as the sample for SFC, a mixture of the above mixture in a 50 mg / ml CH ₂ Cl ₂ solution was used.

<SFC condition 2> Apparatus: "Jasco S" manufactured by JASCO Corporation
UPER-201 "Column type and shape: superpack SIL,
4.6 mmφ × 250 mm Eluent and its flow rate: CO ₂ 3.0 ml / min EtOH 0.5 ml / min Pressure: 20 MPa Temperature: Temperature decrease from 80 ° C. to 40 ° C. at a temperature decrease rate of 3 ° C./min. Sample injection volume: 3 μl (sample loading 150 μg)

FIG. 3 shows a chromatogram obtained by performing multi-wavelength simultaneous measurement in the same manner as in Example 1. The separation state of each component was good. Also, with this sample loading, only 1
The SFC ended in 0 minutes.

When the supercritical fluid is used for the extraction with the supercritical fluid, for example, an apparatus having the structure shown in FIG. 4 can be used. CO ₂ as eluent
When CO ₂ is used, the CO ₂ passes from the CO ₂ cylinder 10 through the eluent supply pipe 11, and passes through the compressor 14 and the heat exchanger 13.
The mixture is adjusted to a desired pressure and temperature by 15 and supplied to the extraction tank 20. A mixture composed of a plurality of polyol (meth) acrylates having different numbers of (meth) acryloyl groups is supplied to the extraction tank 20 from a mixture supply pipe 21. The components extracted by the supercritical fluid state CO ₂ in the extraction tank 20 are sent to a separation tank 30 where CO ₂ is extracted.
_It is separated from ₂ and taken out of the system. The CO ₂ removed from the extract is transferred from the recycle pipe 12 to the eluent supply pipe 1
It returns to 1 and is again supplied to the extraction tank 20. In this apparatus, for example, 72.8Atm pressure of CO ₂ gas cylinder 10 and the compressor 14, 0 ° C. The cooling temperature of the CO ₂ in the heat exchanger 13, the cooling temperature of the CO ₂ in the heat exchanger 15 31. 1 ° C., the pressure in the extraction tank 20 is 300 to
100 kg / cm ² , the pressure in the separation tank 30 is 50-60
kg / cm ² .

Comparative Example 1 The polyol acrylate mixture obtained in Example 1 was dissolved in tetrahydrofuran,
g / ml. With respect to this solution, purification of the tri-substituted product and the tetra-substituted product was attempted by GPC under the following conditions. <GPC analysis conditions> Apparatus: manufactured by Tosoh Corporation, trade name "HLC-802"
0 ”column type and shape: TSK-Gel GMH
_XL-L (7.8 mm φ x 300 mm) x 4 Eluent and flow rate: Tetrahydrofuran 1.0 m
l / min Sample injection volume: 100 μl

FIG. 5 shows the obtained chromatogram. 3
Peaks are observed around 1.0 min and 33.5 min. From the retention time, the peak at 33.5 min is a monomer containing a di-, tri-, or tetra-substituted acrylate.
The peak at 0 min is presumed to be a dimer. As described above, it was not possible to separate the polyol acrylate by the number of acryloyl groups by GPC at all.

The present invention is not limited to the specific embodiments described above, but may be variously modified within the scope of the present invention in accordance with the purpose and application. For example, in the above example, the purification of the polyol acrylate was performed by only one SFC, but the fraction F1,
It is also possible to further increase the purity of each compound by performing SFC again using F2 as a sample. Further, in the above embodiment, the tri-substituted and tetra-substituted substances were subjected to purification, but the treatment with a supercritical fluid may be performed with only one type of substituted object as the object of purification, or each of all substituted substances may be treated. Fractions containing the substituted product with high purity may be fractionated.

[0041]

According to the method of the present invention, a specific (meth)
It is possible to produce a polyol (meth) acrylate having an acryloyl group with high purity, relatively high productivity and high yield. Since the specific (meth) acrylate has less variation in composition, the performance of the cured product and the like is stable. Further, by utilizing the high purity, it is also possible to develop into a field different from the conventional one.

[Brief description of the drawings]

FIG. 1 is a chromatogram obtained by SFC in Example 1.

2 (a) is a ¹ H-NMR chart of a fraction F1, and FIG. 2 (b) is a ¹ H-NMR chart of a fraction F2 among the fractions obtained by the SFC of Example 1. FIG.

FIG. 3 is a chromatogram obtained by SFC in Example 2.

FIG. 4 is a schematic diagram showing an example of an apparatus used for performing supercritical extraction in the production method of the present invention.

FIG. 5 is a chromatogram obtained by GPC in Comparative Example 1.

[Explanation of symbols]

Reference Signs List 10 CO ₂ cylinder 11 Eluent supply pipe 12 Recycle pipe 20 Extraction tank 21 Mixture supply pipe 30 Separation tank

Claims (4)

[Claims] 1. A synthesis step of obtaining a mixture comprising a plurality of polyol (meth) acrylates having different numbers of (meth) acryloyl groups by subjecting (meth) acrylic acid and a polyol to an esterification reaction; (Meth) polyol having a specific (meth) acryloyl group number
A method for producing a polyol (meth) acrylate, comprising: a purification step of separating an acrylate from another polyol (meth) acrylate. 2. The polyol (meth) acrylate according to claim 1, wherein the treatment with the supercritical fluid is at least one treatment selected from extraction with a supercritical fluid and column chromatography separation using the supercritical fluid as an eluent. Manufacturing method. 3. The method for producing a polyol (meth) acrylate according to claim 1, wherein the supercritical fluid is a fluid composed of CO ₂ . 4. The method for producing a polyol (meth) acrylate according to claim 1, wherein the supercritical fluid is a fluid composed of a mixture of CO ₂ and a lower alcohol.