Vegetal Oil Derivatives Plasticizers TECHNICAL FIELD

The following descriptive report of the invention application refers to the development of oil vegetal derivatives comprising the use of the interesterification reaction between vegetal or animal oils and monoacid esters (preferentially with 1 to 12 carbons) and monoalcohol esters (preferentially with 1 to 12 carbons) The use of ethyl acetate is preferred as it is a product that can be obtained from ethanol (renewable) and has a low boiling point (77 ⁰ C), which facilitates the separation by vacuum distillation at the end of the reaction and its reuse.

Vegetal oils are interesterified with monoacid and monoalcohol esters, in the presence of a catalyst, generating a mixture of glycerol esters with short and long chain acids simultaneously bound to polyol. Also fatty acid esters are formed with alcohol. The product from this reaction may be epoxidized with hydrogen peroxide, obtaining a low viscosity product applied as a plasticizer for polar polymers such as PVC and NBR.

ART BACKGROUND

Oils with the composition proposed in this patent were not found in the technical literature or described in patents. All one finds are products derived from the triacetin (glycerol triacetate) interesterification reaction with triglycerides. The process is described in the US patent 5,434,278, which suggests a combination of triacetin with tripropionin and tributyrin to get around the problem of low solubility of triacetin in oils and fats with resulting reaction difficulty. This problem does not occur in the reaction with monoalcohol and monoacid esters. It can be predicted that oils with the composition that has been obtained will have applications as emollients in cosmetics, solvents for use in industrial and home cleaning, plasticizers for low-polarity polymers such as natural and synthetic rubbers, and as a fluid for use in petroleum well drilling. The interesterification reaction was repeated, replacing the vegetal oil with epoxidized vegetal oil. With this, it was intended to obtain a product of greater polarity and greater stability to oxidation, aiming at its application as plasticizer

for polymers of greater polarity such as, for example, vinyl polychloride and rubbers containing acrylonitrile.

The most used plasticizers for this purpose are the esters from phthalic anhydride, the phthalates.

The US patent 6,734,241 proposes the use of monoglycerides from castor bean oil or hydrogenated castor bean acetylated as plasticizers and it demonstrates its efficiency for PVC plasticization. The problem is that the product would have a high production cost due to the production process and the cost of the castor bean oil.

The US patent 7,071 ,343 proposes the use of the product from the interesterification of epoxidized vegetal oil with triacetin (glycerol triester with acetic acid) or the interesterification of triacetin with epoxidized fatty acid methyl ester.

The reaction of the epoxidized vegetal oil with triacetin is carried out at 22O ⁰ C in the presence of a catalyst for 3-4 hours in the examples.

In a comparative evaluation with DOP and DOA and using up to 100 PHR plasticizer in combination with PVC, no exudation occurred. Shore A hardness was higher than that obtained with DOP. Thermal stability at 180 ⁰ C was substantially improved.

The US patent 5,643,301 assesses the effect of zinc stearate used as thermal stabilizer in PVC composites, containing esters from epoxidized fatty acids, and concludes that the maximum content of zinc stearate must be 0.1% of the PVC mass, otherwise the zinc chloride formed may catalyze the thermal degradation of the polymer and also polymerization reactions of the epoxidized esters may occur, causing defects on the surfaces of the pieces produced.

DESCRIPTION OF THE INVENTION

The objective of this invention is to obtain plasticizers derived from renewable feedstock, combining suitable availability of raw material, low energy consumption, low impact of generated effluents, effectiveness in the final performance as plasticizer, biodegradability, and biocompatibility. For this purpose, compounds were synthesized containing glycerol esters with short chain acids (preferentially acetates) and epoxidized fatty acids, in a combination between epoxidized fatty acid esters and monoalcohol (preferentially ethanol).

The interesterification process according to the present invention is catalyzed by basic compounds such as lithium, sodium or potassium hydroxides, and preferentially by alkoxides from these metals such as sodium or potassium methoxide. The necessary amount of catalyst ranges from 0.01% to 1% by weight and more particularly between 0.3% and 0.6% by weight.

The achievement process is carried out at a temperature from 60 ⁰ C to 125 ⁰ C.

To facilitate viewing the reaction the following formulas are established:

G-(F)3 - glycerol triester with 3 fatty acids;

Et-Ac - ethyl acetate;

G-(F)2 Ac - ester glycerol with 2 fatty acids and 1 acetic acid;

G-F (Ac)2 - ester glycerol with 1 mol fatty acid and 2 mol acetic acid;

Et-F - fatty acid ethyl ester.

In the presence of a catalyst and at a suitable temperature, a redistribution of different acids bound to alcohols occurs.

The composition obtained depends on the proportion between reagents.

It has been determined that for obtaining a product with an average composition of 1 mol G(F)2Ac plus 1 mol Et-F an excess of 40% ethyl acetate must be used.

1 G-(F)3 + 1.4 Et-Ac = 1 G(F)2Ac + 1 Et-F + 0.4 EtAc

To obtain a product with an average composition of 1 mol G-F (Ac)2 plus 2 mol

Et-F, an excess of 100% ethyl acetate must be used.

1 G(F)3 + 4 Et-Ac = 1 G-F (Ac)2 + 2Et-F + 2 Et-Ac

After reaching the reaction equilibrium, the catalyst is neutralized with acid and the excess volatile ester is vacuum distilled. The salt formed is removed via filtration.

Using vegetal oil such as soy oil, esters are obtained which contain unsaturations derived from oleic, linoleic and ϋnolenic acids.

From the epoxidized vegetal oil a composition is achieved with the same ester composition, but with the difference that unsaturations are replaced with oxirane groups.

There is no hindrance or damage if interesterification is performed first and then epoxidation, which is a public domain process, and in industrial scale is usually performed using peracids such as performic or peracetic acids generated in situ by the reaction of organic acids with hydrogen peroxide.

As for the oils used, it is desirable that these do not contain a very high concentration of saturated fatty acids, as these cannot be epoxidized and, consequently, generate products of lower polarity.

EXAMPLES

Substances used:

- Epoxidized soy oil - Olvex 60, SGS Polfmeros Ltda.

- Ethyl acetate - Rhodia (99.5% minimum)

- Sodium methoxide - Degussa (29.5% minimum)

- Glacial acetic acid - Rhodia (99.5% minimum)

- Vinyl polychloride - Norvic SP 1000 (Braskem®)

- Dioctyl phthalate - Elekeiroz (99%)

- Diisobutylphthalate - Elekeiroz (99%)

- NBR (acrylonitrile/butadiene rubber) - N 515B (Nitrflex)

- Ca/Zn Markstab IBZ-524 stabilizer (Inbra)

- Accelerator - Linkwell TBBS (N-tert butyl-2-benzothiazol sulfenamide)

EXAMPLE 1 lnteresterification of soy oil with ethyl acetate to obtain a product with molar ratio G-(F)2 Ac / EtF =I

Load the reactor equipped with stirring system and condenser with 879 g soy oil, 123g ethyl acetate, and heat at 90 ⁰ C under nitrogen atmosphere. Add 4.4g sodium methoxide. Heat at 115°C and maintain for 1 hour. Add 1.5g acetic acid to neutralize the catalyst. Heat at 125 ⁰ C, distilling the excess ethyl acetate.

Create vacuum by maintaining for 1 hour a 40 mmHg absolute pressure.

Cool at 90 ⁰ C and add 88g water for washing, keeping under stirring for 1 hour.

Decant for 1 hour and drain the water phase. Reheat at 125°C and reapply vacuum for drying until the humidity content is below 0.2%.

A 48g product is generated, and 49g ethyl acetate is recovered by condensation.

Characterization of the product obtained:

- Water content by Karl Fisher 0.028%;

- Saponification index 218.300mg

KOH/gram;

- Acidity index 44.000mg KOH/g;

- Brookfield viscosity at 25° C 33.00OcPs (spindle

1/100 rpm);

- Density at 20 ⁰ C 0.927 g/cm ³ .

EXAMPLE 2 lnteresterification of soy oil with ethyl acetate to obtain a product with molar ratio G-F(Ac)2 / EtF = 0.5.

The reactor was loaded with 879g soy oil and 325g ethyl acetate.

The process from example 1 was repeated with the same amount of catalyst

(4.4g), and 105Og of the product was obtained and 175g ethyl acetate was recovered.

Characterization of the product obtained:

- Water content by Karl Fisher 0.027%;

- Saponification index 237.00mg KOH/gram;

- Acidity index 1.63mg KOH/g;

- Brookfield viscosity at 25°C 21.0 cPs (spindle 1/100 rpm);

- Density at 20 °C 0.919 g/cm ³ .

EXAMPLE 3 lnteresterification of epoxidized soy oil with ethyl acetate to obtain a product with molar ratio G-(F)2 Ac / EtF =1.

The reactor was loaded with 94Og epoxidized soy oil with 6.5% oxirane content and 123g ethyl acetate.

The conditions of the example 1 were repeated, but the amount of sodium methoxide was increased to 46g. 1010g of the product was generated, and 46g ethyl acetate was recovered by condensation.

Characterization of the product obtained:

- Water content by Karl Fisher 0.082%;

- Acidity index 0.95 mg KOH/g;

- Brookfield viscosity at 25 ⁰ C 150.0 cPs (spindle

1/20 rpm);

- Density at 2O ⁰ C 0.988 g/cm ³ ;

- Epoxy content 5.85%;

-Sludge content 1.15gl2/100g sample

EXAMPLE 4 lnteresterification of epoxidized soy oil with ethyl acetate to obtain a product with molar ratio G-(F)2 Ac / EtF =0.5.

The reactor was loaded with 94Og epoxidized soy oil with 6.5% oxirane content and 325g ethyl acetate.

The conditions from example 1 were repeated, but the amount of sodium methoxide was increased to 46g.

1095g of the product was generated, and 48g ethyl acetate was recovered by condensation.

Characterization of the product obtained:

- Water content by Karl Fisher 0.105%;

- Acidity index 0.830mg KOH/g;

- Brookfield viscosity at 25°C 78.0 cPs (spindle

1/50 rpm);

- Density at 20°C 0.994 g/cm ³ ;

- Epoxy content 5.06%;

- Sludge index 1.19gl2/10Og sample

APPLICATION EXAMPLES

The performance of the product obtained was compared with DOP in nitrile rubbers compounds and also in combination with PVC.

The physical-mechanic properties of nitrile rubber compounds (Nitriflex N 615B) were assessed, these contained 33% acrylonitrile and were plasticized with dioctylphthalate and with the product obtained in example 4. The formulation is based on the ASTM D3187-00 standard.

Rheometric curves were performed at 170 ⁰ C. The sulfur content of the compounds was adjusted to achieve similar rheologic curves. The results can be seen in Tables 1 and 2.

Graphic 1 shows the overlapping of the rheometric curves obtained for the five compounds.

Graphic 2 shows the overlapping of rheometric curves following the adjustment of the sulfur content.

Table 3 shows the physical-mechanical and chemical properties for the white compound, 10 phr DOP, 20 phr DOP, for example 4 - 10 phr, and for example 4 - 20 phr. Table 4 shows the rheometric curve for 10 phr DOP, 20 phr DOP, for example 4

- 10 phr, and for example 4 - 20 phr.

Table 5 shows accelerated aging at an oven, 70 h at 125 ⁰ C for 10 phr DOP, 20 phr DOP, for example 4 - 10 phr, and for example 4 - 20 phr. Table 6 shows the permanent deformation under compression test at 22h and 124 ⁰ C for 10 phr DOP, 20 phr DOP, for example 4 - 10 phr, and for example 4

- 20 phr.

The product obtained in example 4 was evaluated as a plasticizer for a PVC resin. The resin Norvic® SP 1000 (Braskem®) was used, which is a homopolymer obtained in suspension, with k value (DIN 53726) of 65 +1 and 95% of particles larger than 63 microns. The amount of plasticizers was determined to obtain a Shore A hardness of 65, using as plasticizers DOP (dioetylphthalate), IDBP (diisobutylphthalate), and the plasticizer obtained in example 4. As a thermal stabilizer, the product Markstab® IBZ-524 was used at 2.4% by weight on the resin along with 5% epoxidized soy oil (Olvex 60). For each 100 parts by PVC weight it was necessary to use the following amounts of plasticizers.

- DOP 78.0 phr;

- DIBP 68.4 phr;

- Example 4 73.9 phr.

The product obtained in example 4 presented an intermediate plasticization ability between DOP and IDBP. The test pieces were examined after 6 months and did not show any migration sign.

TABLE 01

TABLE 02

Physical-mechanical and chemical properties

TABLE 03

TABLE 04

Rheometric curve: arch ± 0.5°, temperature 170 ⁰ C, time 30 min, frequency 100 cpm

TABLE 05

Accelerated aging at oven, 70 h at 125 ^° C

TABLE 06

Permanent Deformation at Compression Test, 22 h at 125°C