DE1007314B - Process for improving, in particular, the electrical and color properties of esters used as plasticizers - Google Patents

Description

For the production of electrical cables, it is of great importance that their sheathing has a very high electrical level Has resistance to avoid loss of performance. If you use vinyl resins for this, play the quality of both the polymer, e.g. B. of polyvinyl chloride, as well as the stabilizer and plasticizer a role. Since the plasticizer is used in proportionally large amounts, the specific resistance has the same of course has a considerable influence on the quality of the cable. Because of this, for the In the manufacture of cables, plasticizers with a high specific resistance are always selected. As a result of their good electrical properties, plasticizers such as octyl phthalate as well as octyl and nonyl sebacate are most common used.

However, the specific resistance of an ester of the aforementioned type does not always have the same value, but rather can vary considerably in order of magnitude depending on the method of preparation and purification of the ester show up to tenfold. These changes in electrical properties are likely due to this for traces of impurities that originate from the raw materials used for production or arise during the production itself and only imperfectly when cleaning the plasticizer be eliminated.

It has now been found that one can reduce the resistivity of plasticizers made up of esters can be improved significantly if you treat them with aluminum oxide.

In addition, this treatment with aluminum oxide weakens the color of the plasticizer as well as a reduction in its water content and acidity. Other substances can be a Discoloration (activated charcoal) or drying (silica gel) cause, but have no effect on the specific resistance; this seems to be a specific action of the alumina.

No matter in which form it is used, aluminum oxide always has a beneficial effect the specific resistance, which can, however, be increased if it is in its so-called "Activated" form, d. H. after heat treatment.

All other things being equal, bauxite increases the specific resistance from 1 to 2.5, while it is sevenfold by dried alumina hydrate and by a certain kind of activated aluminum oxide (»Activalum« -) around the Is increased 15 times.

It is known that the absorption capacity of aluminum oxide and other adsorbents (bleaching earth) can be used to treat transformer oils and remove the impurities, especially sludge,

Process for improving the electrical and color properties in particular

of as a plasticizer

serving esters

Applicant:

S. A. Les Usines de Meile,

Saint-Leger-les-Melle, Deux-Sevres

(France)

Representative: E. Maemecke, Berlin-Lichterfelde West, and Dr. W. Kühl, Hamburg 36, Esplanade 36 a,

Patent attorneys

Claimed priority: France, May 5, 1952

Maurice Mention and Pierre Bourguignon, Mile, Deux-Sevres (France), have been named as inventors

to remove adsorptively. It is also known to decolorize esters using bleaching earth. Present invention is based on a peculiar phenomenon that cannot be addressed as a mere adsorption process; because if you use adsorbents other than aluminum oxide (e.g. bleaching earth) as plasticizers Let the ester act, you can see that the electrical resistance does not increase, but rather in the Conversely, it is humiliated at times. The present invention is therefore based on the knowledge of one for Treatment of esters used as plasticizers by means of aluminum oxide. A completely new phenomenon.

The implementation of the method according to the invention must take place at a temperature between 20 and 200 °, at which the ester is sufficiently liquid.

In the case of intermittent treatment, aluminum oxide is kept in suspension in the plasticizer by stirring, the mass being brought to the desired temperature and stirring continued for some time. To achieve a good effect, aluminum oxide in powder form in quantities of 10 / are used liquid to be treated at temperatures between 20 and 200 ° 30 ° ₀ of the weight of the must to. The longer the contact time, the stronger the effect; However, even with a contact time of a quarter of an hour, the maximum achievable effect is achieved.

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The treatment can also be carried out continuously. unchanged specific resistance due to the invented

In this case, however, granulated alumina is considerably increased in a treatment according to the invention

Brought container to which the previously heated soft is. Distilled products can also be used

power is steadily supplied. Softening or products that are discolored by hydrogenation

making agent flows through the aluminum oxide layer 5. In the latter case, the improvement is

and leaves it with improved electrical properties of the color value and the stability, which by the

stocks. As in the case of sales hydrogenation, the temperatures can change from a renewed discoloration and

have operation between 20 and 200 °, preferably an increase in the specific resistance through the

wise they are 60 to 80 °. Accompanied in the steadily carried out method according to the present invention.

The choice of temperature depends mainly on the procedure. In the following examples, the implementation of the

the viscosity of the plasticizer; the viscosity must be described in the method according to the invention. Here

by maintaining an appropriate temperature, the color values were measured with the 6-inch cell of the Lovibond

can be reduced far so that the pressure loss is measured in the colorimeter.

Passage through the aluminum oxide layer not too _. . ,,

becomes big ₁₅ example 1

In general, a column with a diameter of 25 cm and

according to the invention the per se known method of a height of 265 cm is activated with aluminum

and devices are used that have a contact oxide (vAlumine Gammagel electro Ό «) of the grain

between the liquid and the finely divided solid 60 to 100 filled.

favor fabrics. The pressure drop also depends on the grain size of 501 per hour at a temperature of 80 ° of the aluminum oxide through this column. The finer the grain is, the flow Oktylphthalat which the following characteristics is greater this loss, so that the working temperature transactions has: correspondingly higher, and the aluminum oxide corresponds Resistivity 1.8 χ 10 ⁵ megohms / cm / ^cm2 / 20 °

must be speaking thinner. In practice, the preferred 25 color value is 5 yellow +1.6 red

wise aluminum oxide with a grain size of 60 to 100, water content 0.8 g / l

turns, d. H. Aluminum oxide, the grains of which have an acidity of 0.0003 mol / l

Network with 60 mesh, but not through a network with After leaving the column, the octyl phthalate

100 meshes each 27 mm go, because such a grain has the following properties:

a wide latitude for the choice of the device 30 Resistivity 10 X 10 ^s megohm / cm / ^cm2 / 20 °

leaves. The latter can just as well be a container with a large color value 2.2 yellow + 0.6 red

Surface and thinner thickness as well as a column of water content <0.1 g / l

be of small diameter but great height. Acid content 0.0001 mol / l

It was found that apart from the consideration of the pressure loss, the shape of the device 35 Example 2 has no influence on the cleaning result, and

Although neither with regard to the specific electrical In a stirred flask one gives 11 octyl phthalate and

Resistance still with regard to discoloration and the 200 cm ^{3 of} dried aluminum oxide hydrate. The octyl

other additional benefits. Of particular importance is phthalate which has the following properties:

the contact time between the ester and the aluminum 40 Resistivity 0.5 X 10 ⁵ megohms / cm / ^cm2 / 20 °

oxide, which in the continuous working method by the color value 6 yellow +1.5 red

Ratio of parts by volume throughput through the aluminum oxide acid content 0.0002 mol / l

layer per room parts layer per hour are specified. After 15 minutes of stirring at 60 °, the phthalate has

can. Quite remarkable results are obtained with one of the following properties:

Injection of up to 4 parts by volume per hour, representing a 45 Resistivity 4 X 10 ⁵ megohms / cm / ^cm2 / 20 °

Contact time corresponds to a quarter of an hour; the color value 2.9 yellow -j- 0.8 red

However, results approach the maximum achievable acid content of 0.0001 mol / l

worth if the feed is between 0.5 and 1 space part

per hour, which corresponds to a contact time between 2 hours

den and corresponds to 1 hour. 50

The method is applicable to all plasticizers serving as a column having the same dimensions as

Ester applicable and in each case gives an increase that of Example 1, but with activated aluminum

their specific resistance. Oxyd of the type "Activalum" is filled with special value

is, however, its application to esters, which in themselves already have a rate of 301 per hour sebacic acid

have a high specific resistance. Here are 55 octyl esters with the following properties:

in particular the esters of aromatic and aliphatic Resistivity 3.5 χ 10 ⁵ megohms / cm / ^cm2 / 20 °

dibasic C ₆ - to C ^ -carboxylic acids with aliphatic color value 4.9 yellow +1.3 red

C ₆ - to C ₁₀ alcohols to be mentioned, such as. B. octyl phthalate, the treatment temperature is 60 °.

Hexyl phthalate, the sebacic acid ester of the octyl and when leaving the column, the product has the following

Nonyl alcohol, the adipic acid ester of octyl alcohol. 60 properties:

The method of preparation of these esters - whether batchwise or Resistivity 45 10 χ ⁵ megohms / cm / ^cm2 / 20 °

steady - influences the end result of the inventive color value 0.4 yellow + 0 red

appropriate treatment just as little as the cleaning treatments, which these esters may already have in Example 4 have previously been subjected to them as far as possible 65

of excess alcohol or water, of their through a column like that mentioned in Example 3

Acidity or its coloring impurities and is filled with the same aluminum oxide

to free. So a phthalic acid ester can be used as a starting material like this, one leaves at a rate of 501 each

be used, which is already decolorized with activated charcoal, its hour of flow adipic acid onyl ester at 70 °

^{its specific resistance 3.2 χ 10 s} due to this treatment with activated carbon 70, its color value

Claims (1)

5 6 2.0 yellow + 0.4 red and its acidity 0.0009 mol / l similar. After the end of this treatment, it is sufficient amounts to. to blow warm air through the aluminum oxide in order to When leaving the column, the adipic acid ester has to remove the remaining acetone,
a specific resistance of 21 X 10 ⁶ , a color value of 0.8 yellow +0.1 red and an acidity of 5 0.00015 mol / l. PATENT CLAIMS: Example 5 ^ Method for improving in particular the Octyl phthalate is initially used as a soft- 25 kg / cm ² and 80 ° according to the above-mentioned process making means serving esters, thereby marked treated. According to this, it has the following properties: ^{10 shows} that the esters are made with aluminum oxide Resistivity 0.35 X 10 ⁵ megohms / cm / cm ² / treated 20 °. Color value 0.5 yellow + 0.2 red 2. Method according to claim 1, characterized in that Acid content 0.0027 mol / l indicates that precipitated or calcined, preferably Water content 1.27 g / l as "activated" aluminum oxide or bauxite The stability tests show that this product ^{turns 1} ^. with regard to the acid content and the color value heat-resistant 3. The method according to claim 1 and 2, thereby resistant is. The phthalate treated in this way is then identified that at 20 to 200 °, preferably according to the invention in a column with activated 60 to 80 ° works. Aluminum oxide "Activalum" at a speed 4. Process according to claim 1 to 3, characterized in that ^x / ₂ volume parts per hour are treated at 80 ° and ^ao indicates that the treatment time is about ¹ J ₁ to 2, the following properties: preferably 1 to 2 hours.
Resistivity 8 X 10 ⁵ megohms / cm / ^cm2 / 20 ° 5. The method according to claim 1 to 4, characterized denotes geFarbwert 0.1 Yellow, that the aluminum oxide in the liquid- Acid content 0.0001 mol / l solid ester suspended during the treatment time Holds moisture 0 ² 5. The results of the stability tests are un- 6. Method according to claims 1 to 4, thereby changed, indicates that the ester is continuously replaced by the To support the passage through which the aluminum allows aluminum oxide to flow. Miniumoxide column can of course be a pressure 7. The method according to claim 1 to 6, characterized in difference between the input and output end 3 ° indicates that one is aromatic or ester of the column either by placing an aliphatic C ₆ - bis (^ (, - dicarboxylic acids with aliphatic Exerts overpressure or below a negative pressure. tables C ₆ - to (^ "- alcohols, especially phthalic The aluminum oxide can acid, adipic and sebacic acid esters of the C ₆ - bis in the following manner to be regenerated: After using a given amount of C ₉ alcohols. Aluminum oxide contains a certain amount of plasticizer. 8. The method according to claim 1 to 7, flowed through it is, which, depending on the properties of the to be identified, that one is treating esters with aluminum oxide The product is between 80 and 300 parts of the room that was previously used for other treatments can be, the aluminum oxide loses its effectiveness - improving its properties. and needs to be regenerated. For this one allows partly acetone at about 50 ° over the aluminum oxide 4 ° I _n publications considered: flow until the color of the acetone flowing off German Patent Nos. 426 996 and 922 848; 0.1 yellow no longer exceeds. For this purpose, British patent specification No. 667 109; Part of aluminum oxide about 3 to 4 parts by volume of acetone requires French patent specification No. 899 846. ι 709 '507/424 4.57