JPS5938254B2 - Manufacturing method of ester plasticizer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an ester plasticizer, and more particularly to a method for producing an ester plasticizer having excellent hue, acid value, and electrical properties.

Ester plasticizers are used in large amounts for plasticizing plastics, and the various properties of these plasticizers have a great influence on the properties of plasticized plastics.

For example, the characteristics of electric wire coated with soft vinyl chloride resin are as follows:
This is largely due to the electrical properties of the ester plasticizer used, and in order to reduce power loss from the wire, the soft vinyl chloride resin used for the coating is required to have extremely high electrical resistance.

Therefore, the conductivity of the ester plasticizer used in this case must be at a minimum, that is, the ester plasticizer itself must have a high electrical resistance. Furthermore, the ester needs to be as colorless as possible from the commercial value of the plasticizer, and it is also required to have a low acid value. The inferiority of these properties of the ester plasticizer indicates that various impurities remain in the ester plasticizer, such as impurities in the manufacturing raw materials, by-products during reaction or purification, or catalyst residues. The presence of these impurities significantly inhibits the thermal stability of the ester plasticizer,
In turn, this adversely affects the thermal stability, electrical properties, etc. of plasticized plastics. Therefore, when producing ester plasticizers, it is necessary to use high-quality raw materials, to perform synthesis under appropriate conditions, and to perform purification after synthesis with great care. Common purification methods for imparting usefulness as a plasticizer to synthesized esters include vacuum distillation, adsorption removal of impurities by activated carbon treatment, and oxidation removal of impurities by permanganate. It is being done.

In addition, there is a method of treatment with alumina (Special Publication Publication No. 31-41
25), an improvement method using magnesium oxide (hereinafter referred to as MgO) (Japanese Patent Publication No. 39-11358), a treatment method using calcium hydroxide (hereinafter referred to as Ca(OH)2) (Japanese Patent Publication No. 45-35045), etc. Are known. However,
The method disclosed in Japanese Patent Publication No. 39-11358 involves contacting the ester plasticizer, which has been purified by a conventional method, with MgO under substantially anhydrous conditions. Less effective. In addition, the special public
The improvement method using Ca(0H)2 in No. 045 involves first kneading the Ca(0H)2 to be used with water to form a slurry or paste, and filtering the resulting wet product at 100 to 300°C.
The modification effect cannot be obtained unless Ca(0H)2 is dried at a specific temperature, and Ca(0H)2 dried outside this temperature range cannot be obtained.
It is said that Ca(0H)2 has little effect on improving properties.
Since the particle size and other factors also have an effect, the Ca(0H)2 used in this method must be prepared under extremely strict conditions. In addition to these methods, attempts have also been made to treat esters using activated clay, which is widely used for decolorizing and refining oils, fats, lubricants, etc., but activated clay has no decolorizing effect on esters. However, it has the disadvantage that it increases the acid value of the ester and deteriorates its stability.

The present invention was made as a result of various researches aimed at improving the conventional method as described above, which is known as a method for improving the properties of ester plasticizers. The ester was added to activated clay MgO and/or calcium oxide (hereinafter referred to as CaO) in the presence of water.
It is written as

) The purpose is to remove impurities (unreacted acids, monoesters, catalysts, side reactants, etc.) that cause deterioration of its properties as a plasticizer, and to improve its properties. be. Therefore, the gist of the present invention is to combine a linear or branched monohydric alcohol having 4 to 13 carbon atoms, an aromatic dibasic acid, an aromatic tribasic acid, or an aliphatic acid having 5 to 10 carbon atoms. A monomeric ester plasticizer obtained by reaction with a dibasic acid is added with 0.1 to 1% by weight of water, 0.01 to 5% by weight of activated clay, and 0.01 to 5% by weight of the ester plasticizer. A method for producing an ester plasticizer, which comprises contacting with 5% by weight of magnesium oxide or calcium oxide.

To explain the present invention in detail, esters to which the present invention can be applied include linear or branched monohydric alcohols having 4 to 13 carbon atoms, aromatic acids (including their anhydrides), or carbon It is an ester obtained by reacting a fatty acid having 5 to 10 atoms in the presence of a catalyst, and is generally called a monomeric ester plasticizer, and is a polyester plasticizer obtained from a dihydric alcohol and a dibasic acid. are distinguished.

Specific examples of the ester include di-2-ethylhexyl phthalate, diindecyl phthalate, ditridecyl phthalate, di-2-ethylhexyl adipate, diisodecyl adipate, trioctyl trimellitate, dioctyl sebacate, and the like. The catalysts used for the synthesis of the esters include, for example, inorganic acids such as sulfuric acid, hydrochloric acid, and phosphoric acid; organic sulfonic acids such as toluenesulfonic acid; acid salts such as acidic sulfates and acidic sulfites; and zinc chloride. In addition to acidic salts such as tin chloride, organic metal compounds such as antimony compounds, tin compounds, zirconium compounds, and titanium compounds, such as butyltin maleate, tetraalkyl titanates, or amphoteric oxides such as antimony trioxide, alumina, and metal salts. Examples include metal compound catalysts such as tin oxalate. That is, the present invention is a method in which the ester obtained using the catalyst as described above is contacted with activated clay and MgO and/or CaO in the presence of water. This can be done in the manner described below.

That is, after ester synthesis, activated clay, MgO and/or CaO, and water are added simultaneously to the ester that has been neutralized, washed with water, dehydrated, dealcoholized, and dried under reduced pressure or distilled, or activated clay is first added. White clay is added first, then MgO and/or CaO and water are added, and then these are separated.

In this case, the appropriate treatment temperature is about 60 to 120°C, and if it is higher than this temperature, water, activated clay, MgO and/or CaO
If the temperature is below 60°C, the processing efficiency will decrease and the processing time will have to be lengthened, which is disadvantageous. Activated clay and MgO used for treatment. Ca
Generally, O can be used as long as it is commercially available, but one with too poor purity is undesirable from the viewpoint of processing effects and back contamination of the ester, so it is best to use one with the highest possible purity and good quality. It is preferable to use the product immediately after manufacture.

The amounts of activated clay and MgO and/or CaO to be used are each appropriately selected from the range of 0.01 to 5% by weight, preferably 0.1 to 0.5% by weight, based on the ester.

If the amount is more than this range, for example, it will be difficult to carry out the cleaning operation after treatment, and if it is less than this, the effect of improving the properties of the ester plasticizer, which is the object of the present invention, cannot be expected. In the present invention, the appropriate amount of water to be present is 0.1 to 1% by weight based on the ester, and if it is smaller than this, activated clay and M
The effect of using gO and/or CaO in combination will be reduced, and if the amount is more than this, the effect of using activated clay and MgO and/or CaO will be reduced, which is also not preferable.

The reason why the treatment of ester using activated clay and MgO and/or CaO in the presence of water according to the present invention is much more effective than when only activated clay and MgO and/or CaO are used. Although it is not clear, the following reasons can be considered.

In other words, taking activated clay and MgO as an example, activated clay mainly contributes to decolorization, and in the presence of water, a part of MgO becomes magnesium hydroxide (hereinafter referred to as Mg(0H)2) and is released from the surface of MgO. As a result, the surface of MgO is significantly activated and the adsorption capacity is increased, and the acid content and impurities in the ester as well as the acid content released from the activated clay are strongly adsorbed. We believe that the fine Mg(0H)2 released from the surface also adsorbs impurities and is then re-adsorbed by MgO, which further increases the adsorption efficiency and dramatically improves the properties as an ester plasticizer. It will be done.

In particular, the deoxidizing effect and the effect of improving insulation properties are remarkable, and by using a small amount of water, the properties as a treated ester plasticizer are further improved (compared to the case where activated clay and MgO are simply used together). It is thought that the combined use of activated clay and CaO in the presence of water is also effective for the same reason as MgO. Next, in order to make it easier to understand the present invention, examples will be described below, but the present invention is not limited only to the following examples.

In addition, % in the examples indicates the weight % with respect to the ester,
The hue was measured according to the method described in the American Public Health Association (APHA) method, and the acid value and VR (volume resistivity) were measured based on JIS-K-6751 (phthalate ester test method). .

Example 1 and Comparative Examples 1 to 2 Using phthalic anhydride and 2-ethylhexanol as raw materials, an esterification reaction was carried out in a conventional manner using sulfuric acid as a catalyst.
After the reaction, crude di-2-ethylhexyl phthalate (hereinafter referred to as
) was neutralized using an alkali, washed with water, and dried by distillation, and 0.5% of activated clay was added to the resulting sho.
After stirring at 5° C. for 5 minutes, 0.3% MgO and 0.5% water were added, the temperature was raised to 105° C., the mixture was stirred for 20 minutes, depressurized, dehydrated, and then filtered through P.

For comparison, a case of treatment using 0.5% activated clay (Comparative Example 1) and a case of treatment using 0.5% activated clay and 0.3% MgO without using water together are shown. The results of the case (Comparative Example 2) are shown in Table 1 below. From the above results, when activated clay is used in combination with MgO and water as in the method of the present invention, the treatment effect is remarkable compared to when activated clay is used alone in the absence of water. It can be seen that it is superior when compared to the case where activated clay and MgO are used together in the absence of MgO.

Example 2 and Comparative Example 3 As in Example 1, after the esterification reaction, 0.5% of activated clay and
The results of the treatment using 0.1% MgO, 0.2% CaO, and 0.5% water are shown in Table 2 below.

For comparison, the results when water was not used are also listed. Example 3 and Comparative Examples 4 to 5 Ester synthesis was carried out in the presence of sulfuric acid, and the same alkali neutralization, water washing, and distillation drying as in Example 1 were carried out. Add 0.5% activated clay to DIDA (diisodecyl adipate),
After stirring at °C for 5 minutes, 0.3% MgO and 0.5% water were added, the temperature was raised to 105 °C, the mixture was stirred for 20 minutes, depressurized, dehydrated, and thoroughly filtered.

For comparison, the results of the treatment using 0.5% activated clay and the treatment using activated clay and MgO without water are shown in Table 3 below. Example 4 and Comparative Example 6~
8 As in Example 1, after the esterification reaction, 0.5% activated clay and C
Add 0.3% aO and 0.5% water and heat at 105°C for 2
After stirring for 0 minutes, the mixture was dehydrated under reduced pressure and then thoroughly filtered.

For comparison, the treatment using 0.5% activated clay, the treatment using 0.3% CaO, and the treatment using 0.5% activated clay and 0.3% CaO with water. Table 4 below shows the results obtained when the treatment was performed without using these substances together. Example 5 and Comparative Examples 9 to 11 0.3% activated clay and CaOO were added to DOA (dioctyl adipate), which was synthesized in the presence of sulfuric acid and subjected to alkali neutralization, water washing, and distillation drying in the same manner as in Example 1. ．．
Table 5 below shows the results of the treatment using 3% and 0.3% water.

For comparison, the results were shown when treated using 0.3% activated clay, when treated using 0.3% CaO, and when treated using activated 5 clay and CaO without water. are shown in Table 5 below. Example 6 and Comparative Example 12 Ester synthesis was carried out in the presence of sulfuric acid, followed by alkali neutralization, washing with water, and distillation drying in the same manner as in Example 1, adding 0.5% and 0.3% activated clay to TOTM (trioctyl trimellitate). of CaO
and 0.3% water and heated to 105°C') After stirring for 20 minutes, dehydration and filtering were performed. For comparison, the results were shown below along with the results obtained when activated clay and CaO were used without water. It is shown in Table 6.

Example 7 and Comparative Example 13 Ester synthesis was carried out in the presence of sulfuric acid, and activated clay 0 was added to dry BBP (butylbenzyl phthalate) that had been neutralized with alkali, washed with water, and dried in the same manner as in Example 1.
．． Add 3%, 0.3% CaO and 0.3% water to 10
The results are shown in Table 7 below, together with the results of stirring at 5° C. for 20 minutes, dehydration and filtering, and the results of treatment using only activated clay and CaO without using water for comparison.

Example 8 and Comparative Example 14 Ester synthesis was carried out in the presence of sulfuric acid, and 0.5% of activated clay was added to DHP (diheptyl phthalate) which had been neutralized with alkali, washed with water, and dried in the same manner as in Example 1 at 85°C. After stirring for 1 minute, 0.3% CaO and 0.3% water were immediately added, the temperature was raised to 105℃, and after 20 minutes of stirring, dehydration and filtration were performed. The results are shown in Table 8 below along with the results when treated with activated clay and CaO alone.

As is clear from the above Examples and Comparative Examples, by treating the ester with the activated clay of the present invention and MgO and/or CaO in the presence of water, the acid value is reduced and the electrical properties are significantly improved. Furthermore, the hue was also improved, and it can be seen that there is a remarkable effect compared to the case of treatment with activated clay and MgO or CaO.

Example 9 and Comparative Examples 15 and 16 Tetraisopropyl titanate (
After esterification using TPT), unreacted alcohol was distilled off under reduced pressure, and 0.2% of activated clay was added to the remaining crude product at 85° C., followed by stirring for 5 minutes.

Then MgOO. Add 2% and 0.5% water, 105℃
After raising the temperature to , it was dehydrated under reduced pressure for 20 minutes and thoroughly filtered. For comparison, activated clay alone (Comparative Example 15) and activated clay and Mg
Table 9 also shows the results when O was added (Comparative Example 16).

Claims (1)

[Claims] 1 having a straight chain or branched chain having 4 to 13 carbon atoms
A monomeric ester plasticizer obtained by the reaction of an aromatic dibasic acid, an aromatic tribasic acid, or an aliphatic dibasic acid having 5 to 10 carbon atoms, with respect to the ester plasticizer. A method for producing an ester plasticizer, which comprises contacting 0.1 to 1% by weight of water, 0.01 to 5% by weight of activated clay, and 0.01 to 5% by weight of magnesium oxide or calcium oxide.