Method for producing environmentally-friendly plasticizers

Abstract

A process for producing an environmentally-friendly plasticizer, which is particularly suitable for use in vehicle tires or technical rubber articles. A vulcanized and/or unvulcanized polymer material of a high molecular weight is converted into a low-molecular phase by direct thermal liquefaction. The vulcanized and/or unvulcanized high-molecular-weight polymer material is provided as a polymer powder and/or a granulated polymer and can be obtained from used tires.

Claims

1. A process for producing plasticizer comprising: providing a feed oil for a conversion of a polymer material to a plasticizer, heating the feed oil to a temperature of from 150 to 300 C. and adding the polymer material to the heated feed oil, converting the polymer material to the plasticizer via direct thermal liquefaction in a single stage reactor, obtaining the plasticizer as a final product from the single stage reactor, and performing the direct thermal liquefaction at the same temperature to which the feed oil has been heated, wherein the polymer material is powder or granulated polymer from rubber tires, and wherein the feed oil is vegetable oil comprising rapeseed oil and/or sunflower oil, or Treated Distillate Aromatic Extracts (TDAE).

2. The process as claimed in claim 1, wherein the polymer material comprises a rubber selected from the group consisting of natural rubber, synthetic rubber, butadiene rubber, styrene-butadiene rubber, and mixtures thereof.

3. The process as claimed in claim 1, further comprising performing the direct thermal liquefaction in a sump phase.

4. The process of claim 1, wherein the feed oil consists essentially of rapeseed oil and/or sunflower oil.

5. The process of claim 2, wherein the yield of plasticizer is 90% or more.

6. The process of claim 1, wherein the feed oil does not undergo full decomposition and does not produce a blank stream at the temperature of from 150 to 300 C.

7. The process of claim 1, wherein converting the polymer material to the plasticizer via direct thermal liquefaction in a single stage reactor occurs at a constant temperature of 300 C. throughout the process.

8. A process for producing plasticizer comprising: providing a feed oil for a conversion of a polymer material to a plasticizer, heating the feed oil to a temperature of 300 C. and adding the polymer material to the heated feed oil, converting the polymer material to the plasticizer via direct thermal liquefaction in a single stage reactor, obtaining the plasticizer as a final product from the single stage reactor, and performing the direct thermal liquefaction at the same temperature to which the feed oil has been heated, wherein the polymer material used is powder or granulated polymer from rubber tires, and wherein the feed oil is Treated Distillate Aromatic Extracts (TDAE).

Description

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

(1) An inventive example will now be used for further explanation of this disclosure. In this connection, Table 1 lists the features of the polymer materials used, and of the plasticizer produced by using the process disclosed herein.

Inventive Example

(2) The polymer material used comprises a rubber powder obtained from a vulcanized mixture for the tread of a truck tire. The rubber powder comprises, as rubber component, high proportions of a natural polyisoprene (NR), low proportions of polybutadiene rubber (BR), and sometimes only traces of styrene-butadiene rubber (SBR). The phr data (parts by 100 parts of rubber by weight) used in Table 1 here are the customary qualitative data used for mixture formulations in the rubber industry. The amount added in parts by weight of individual substances here is always based on 100 parts by weight of the entire composition of all of the rubbers present in the mixture. The inventive example relates to laboratory-scale experiments, and for industrial applications the corresponding parameters have to be adapted appropriately, in particular depending on the size of the corresponding reactor.

(3) The plasticizer oil was produced by the process disclosed herein. TDAE oil was used as feed oil. 302.42 g of TDAE oil (VIVATEC 500, Hansen-Rosenthal KG, Hamburg) were heated to 300 C. in a reaction apparatus of volume 1 l. The heating phase takes 80 minutes to reach the desired bottom temperature of 300 C. This is then maintained for 22 minutes in order to record what is known as the blank value. The blank value is a product mass flow rate resulting from the cracking of the feed oil. This flow rate is also present subsequently during the addition of the polymer material, and the total condensate mass flow rate during the experiment is therefore composed of the blank value and of the mass flow rate resulting from the addition of the polymer material. Once the heating time has expired, the introduction of the polymer material is begun. Another factor to be considered here is a change of fraction, to permit better evaluation of the effect of the polymer material on the condensate produced. During the controlled and continuous introduction of the polymer material, the torque of the stirrer in the reaction apparatus is observed, in order to ensure that the viscosity of the bottom product does not rise excessively. In the event of temporary viscosity rises, the introduction of the polymer material can be briefly interrupted in a controlled manner. In the present inventive example, 604.31 g of polymer material are added at a rate of 111.57 g/h within a period of 325 minutes. The temperature is maintained at 300 C. during the entire direct thermal liquefaction process.

(4) Table 1 shows that there is no residual content of high-molecular-weight polymer material.

(5) The following test methods were used, insofar as these are not stated directly in the Table: Acetone extract (=entirety of all of the substances extractable from the vulcanized rubber mixture, for example antioxidants, plasticizers, et cetera) in accordance with DIN ISO 308 Carbon black content, using TGA in accordance with DIN 51006 Residue on ignition at 550 C. in accordance with DIN 53568, DIN 12904, DIN 12491 Sulfur content in accordance with ASTM D2622 Glass transition temperature Tg in accordance with ISO DIS 28343 Content of polycyclic aromatics (PAH value) in accordance with IP 346 Nitrogen content based on ASTM 147 Zn, Cu, Fe content based on ASTM D7260

(6) TABLE-US-00001 TABLE 1 Test method Unit Powder 1 Plasticizer oil Acetone extract % 6.4 Carbon black % by wt. 28.7 15.2 content Residue on % 6 3.2 ignition Sulfur content % 1.22 1.11 Tg C. 62 17 NR phr 83 BR phr 17 SBR phr traces PAH % 0.12 Nitrogen content % 0.23 Zn % 1.06 0.58 Cu mg/kg 1.4 3.5 Fe mg/kg 24.9 7.6 Viscosity @ RT n.a. paste-like

(7) It is understood that the foregoing description is that of the preferred embodiments of the invention and that various changes and modifications may be made thereto without departing from the spirit and scope of the invention as defined in the appended claims.