BRPI0905054A2 - process for obtaining poly (ethylene terephthalate) alkyd resin after consumption or not, with reduced reaction time - Google Patents

Abstract

<B> PROCESS OF OBTAINING ALKIDIC RESIN BASED ON POLY (ETHYLENE TEREFTALATE) POST-CONSUMPTION OR NOT, WITH REDUCED REACTION TIME <D> a process for obtaining alkyd resin based on poly (ethylene terephthalate) is described , PET, from post-consumer carbonated beverage bottles, or not, with the objective of meeting the needs of the paint industries. The manufacture of alkyd resin requires the use of polyacids and polyalcohols. In this invention, part of the polyacid to be consumed in the reaction was replaced by the polyester residue from the bottles. In this synthesis, part of the phthalic anhydride was replaced by post-consumption PET in the proportion of 1-50% by mass. The reactions were carried out in 2 stages, in the first one the alkalysis was performed and in the second the esterification. The lithium octoate catalyst provided a 50% gain in the alcoholization time compared to the reaction times found in the literature, which were 60 mm. The insertion of post-consumer PET in the alkyd resin provided a decrease in the esterification reaction time, in obtaining process water and in the need for virgin raw material (phthalic anhydride).

Description

PROCEDURE FOR OBTAINING POST-CONSUMPTION DEPOLI (ETHYLENE TEREPHALATE) BASED RESIN WITH RESPECT TIMES

FIELD OF INVENTION

The present invention pertains to the field of processes for obtaining poly (ethylene terephthalate) alkyd deresine, PET1 from post-consumer or non-consumed packaging, specifically by alcohol and polyesterification processes, with reduced reaction time.

BACKGROUND OF THE INVENTION

The increasing use of plastic packaging and the environmental implications arising from its unreasonable disposal are worrying society worldwide. On the other hand, the profitability of the packaging recycling market shows attractive aspects to business initiatives, with direct socio-economic consequences, among them, the improvement of the population due quality, higher income generation, greater natural resource economy and environmental problems mitigation.

Poly (ethylene terephthalate), PET, is a synthetic polymer widely used for packaging because it is an engineering plastic priced close to a commodity plastic and has specific characteristics when replacing other materials, such as glass. Another advantage of this desepolymer is its great recycling potential, which allows the conservation of petrochemical and energy raw materials.

Another point that should be emphasized is that PET does not cause any chemical reaction with the organism of humans and is not environmentally hazardous, but due to the substantial volumetric fraction occupied by landfills and its high resistance to biological agents, it is seen as harmful material.

The largest market for recycled PET in Brazil is the production of polyester fiber for the textile industry, which is applied in the manufacture of sewing threads, upholstery, rugs, carpets, nonwoven blankets (TNT), among others. It is also intended for the production of thermoformed artifacts as well as the manufacture of new bottles for non-food products.

An equally promising market for recycled PET is that of chemical resins, which make it possible to use bottle flake to make unsaturated polyester resins, to produce adhesives, polyurethane foams and alkyd resins used in the production of paints. The recycling way to obtain these products is chemistry. PET recycling can also be performed mechanically and energetically.

The growing public awareness of the environment has stimulated the development of increasingly rational, economic and environmentally clean processes by industries. As a result, paint manufacturers also develop technologies that seek lower costs, high quality product finishes and compliance with increasingly stringent environmental and occupational safety legislation. The use of materials discarded by other industrial segments, such as PET packaging, was one of the sources for the supply of raw materials that paint manufacturers followed to reach a more economical production, such as the production of alkyd paints.

The manufacture of alkyd resin requires the use of polyacids and polyalcohols, which are generally sourced from nonrenewable sources of raw material such as pentaerythritol, trimethylolpropane, glycerol, phthalic anhydride, maleic anhydride, benzoic acid etc.

Alkyd resins are obtained by reacting a polyacid with polyalcohol modified vegetable oils or by reacting a polyacid with fatty acids and polyalcohol, which results in a modified polyester. Reaction of polyalcohol with a polyacid produces a very hard and brittle polyester, so it is necessary to introduce vegetable oil or fatty acid to improve its flexibility.

There are basically three processes for introducing fatty acids into the composition of alkyd resins: "fatty acid" process, "alcohololysis" process and "acidolysis" process. The "alcohololysis" process enables the use of vegetable oils whose reaction products are added to a polyol or a polyacid for the preparation of alkyd resins.

In the "alcohololysis" method, oils in the form of triglycerides do not react directly with the polyester components and therefore are not incorporated into the alkyd structure without prior modification. In this case (by the "alcohololysis" method) the resin is processed in two steps, the first being the alcohololysis to form a monoglyceride and the second step is a esterification reaction, ie the reaction of the monoglycerides with carboxylic acid.

Kawamura et al. (Kawamura, C., Ito, K., Nishida, R., Yoshihara, I., Numa, N. Coating resins synthesized from recycled PET. Progress in Organic Cooings, vol. 45, pp. 185-191, 2002.) developed post-consumer PET resin resins for post-synthesized paint replacing ethylene glycol and terephthalic acid, which had the same structures and characteristics as those composed of conventional polyester. The developed polyester was first obtained from the depolymerization of PET with neopentylglycol and otrimethylolpropane in the presence of catalyst. The temperature used was 210 ° C and maintained until the reaction medium became clear (4h). After this step isophthalic acid was added and the medium heated to 240 ° C for 3h until the desired acidity index was reached.

Kawamura and colleagues also synthesized an alkyd resin from PET (US 6,686,399 B1, 2004), replacing part of the ethylene glycol and phthalic anhydride, which was used to manufacture paints for ambient temperature curing. The products developed presented characteristics and properties similar to commercial alkyd resins. In this work pentaerythritol and ethylene glycol were first added to the reactor. The medium was heated to 140 ° C until complete fusion of pentaerythritol. Zinc acetate (catalyst) and recycled PET were added. The medium was heated to 230 ° C and kept at this temperature for 1h for PET depolymerization. The temperature was lowered to 180 ° C for addition of soybean oil fatty acid, phthalic anhydride and xylene for reflux. After the reagents were added, the system was heated to 240 ° C and maintained under these conditions for 3h. After synthesis, alesic aresine was diluted with turpentine.Bersh (Bersh, Ρ.I., Master's dissertation: Chemical recycling depoli (ethylene terephthalate): Obtaining resins for paints. Pontifical Catholic University of Rio Grande do Sul. Mara OliveiraEinloft and Jeane Dullius, 2005) performed the synthesis of a post-consumer PET-based alkyd resin by the alcoholysis method. In the first stage, the soybean oil alcoholization was sandblasted and in the second stage the polyesterification reaction was performed. The reactor was charged with soybean oil, lithium catalyst hydroxide and water. The medium was heated to 200 ° C and opentaerythritol was added and maintained under these conditions for 1h (alcohololysis). After complete alcoholysis the medium is heated to 230 ° C and the PET and debuthydroxy tin oxide are added and maintained at this temperature for 30 min until all PET melts and decreases to 190 ° C. In the second step, ethylene glycol, phthalic anhydride and fumaric acid are added. The system is reheated to 190 ° C for 30min and adds pentaerythritol and xylene for reflux. The medium is then heated at 230 ° C for 2h and added more xylene and maintained at 230 ° C until the desired acidity is reached. After resin synthesis, the medium temperature is reduced to 180 ° C and diluted with turpentine. The total esterification time lasted from 150 min to 225 min, depending on the amount of PET used.

Karayannidis et al. (Karayannids, GP, Achilias, DS, Sideridou, ID, Bikiaris, DN. Alkyd resins derived from glycolized wastepoly (ethylene terephthalate). European Polymer Journal, vol. 41, p.201-210,2005.) of post-consumption PET glycolysis by diethylene glycol (DEG) and the products obtained from this glycolysis were used in the synthesis of unsaturated polyester resin for paint production. PET polymerization was performed using different proportions of diethylene glycol / PET (1:20 and 1:60). The catalyst used for transesterification was magnesium acetate (0.5% w / w). The reactor was heated for 4 h at 210 ° C under argon atmosphere. The glycolysis products were taken to an ice bath and then filtered. The oligomers produced were extracted with dichloromethane and washed with water to remove traces of DEG. The unsaturated polyester resin was synthesized under an inert argon atmosphere and constant stirring. The reactor was charged with phthalic anhydride, maleic anhydride, propylene glycol and oligomers from PET glycolysis. The reaction medium is heated to 200 ° C for approximately 9h. After removal of a predetermined amount of water, the system was cooled to 90-1000 ° C and styrene-diluted.

Dullius et al. (Dullius, J., Ruecker, C., Oliveira, V., Ligabue1 R., Einloft, S. .. Chemical recycling of post-consumer PET: Alkyd resins sintesis.Progress in Organic Coatings, vol. 57, p -123-127, 2006) synthesized alkyd resin using various vegetable oils, fatty acids and post-consumer PET for alkyd paints. In this study, the reaction time and resin properties were evaluated using soybean oil, linseed oil and sunflower oil; and the fatty acids of coconut oil and tall oil (mixture of pitch-based fatty acid from the pulp industry) with different catalysts (lithium hydroxide, potassium hydroxide and tin oxide). According to the reagents used (vegetable oil or fatty acid) different routes were adopted. For vegetable oil syntheses, first the reactor was charged with the oil and the catalyst (LiOH or KOH), the medium was then heated to 235 ° C for the addition of pentaerythritol. For alcohololysis the system was kept heated for 1h at 240 ° C. After alcoholysis, a tin based catalyst, PET flake, phthalic anhydride and ethylene glycol were added. The medium was heated to 240 ° C until the esterification reaction was completed and the acidity index of 18mgKOH / g resin was reached, which led to a time of about 4h30min. For fatty acid synthesis, the fatty acid and catalyst (LiOH or KOH) are normally added. The medium was heated to 235 ° C for addition of pentaerythritol. The temperature was maintained at 240 ° C for 1h and the tin-based catalyst, PET and ethylene glycol added. The medium was heated to 240 ° C until the esterification reaction was completed and the acidity index of 18mgKOH / g of resin was reached, which took around 2h.

The esterification reaction via synthesized fatty acid was low, but to achieve this result Dullius used two catalysts, one in the first phase and another in the second when PET was added. In addition, this fatty acid process uses a raw material that is not easy to store because it is more unstable than vegetable oil. In Brazil due to the ease of obtaining vegetable oils, the preference is to use this raw material. Another advantage of viaololysis (vegetable oil) synthesis is in the process temperature, which may be lower than in fatty acid synthesis.

US 3,951,886 (1976) describes a process for producing polyester resins from the use of discarded polyesters, such as saturated polyester comoresin, alkyd resin and unsaturated polyester resin. In this process the post-consumer polyester is depolymerized with at least one polyol in the presence of titanium-based catalysts and subsequent polycondensation of the depolymerization products with a polyacid or anhydride. In this invention PET, neopentyl glycol and catalyst (titanium depotassium oxalate in the proportion of 0.01 to 0.10% of the post-consumption polyester mass) are first added. The mixture is heated under nitrogen to 2100 ° C for 30 min and kept at this temperature for an additional 1h30min. After this time, the sebacic acid is added, kept for 30 min at 220 ° C and then warmed to 250 ° C for an additional 30 min. After this time the system pressure is reduced to 1mmHg, warmed to 280 ° C and maintained at 30min. The system is cooled and the polyester resin formed. The total time of this synthesis was approximately 4h, but in order to obtain this low processing time it was necessary to work with reduced pressure in one of the reaction steps and also to use very high temperatures, which caused a dark product.

US Patent 5,252,615 (1993) describes post-consumer aqueous PET coating systems. In this work, PET is first submitted to alcohololysis splits to decrease its molar mass and later daresin synthesis. PET alcohololysis is performed in a stirred reactor, atmospheric container and condenser. The reactor is charged with PET1 trimethylol propane, tin and xylene catalyst. The medium is heated to 238 ° C until all components are melted and the solution clear. The solution is cooled to 163 ° C and trimellitic anhydride and castor oil fatty acid added. The system is heated to 243 ° C and maintained under these conditions until it reaches the specified acidity index. After cooling the medium the resin is diluted with water and triethylamine in proportion: 65g resin / 65g water / 6.1g triethylamine.

Ito et al. (US 6,534,624 B2, 2003) were one of the researchers to patent the use of terephthalic acid from PET chemical recycling to make alkyd resin. The process consists of post-consumption PET depolymerization along with the esterification reaction. In this synthesis pentaerythritol, ethylene glycol, soybean oil fatty acid, soybean oil and phthalic anhydride are first added. The medium is heated to a temperature of 140 ° C, when a mixture of catalyst composed of lithium and acetate teninco (0.3% of each) is added. At this stage PET is also added. The reaction medium is heated to 240 ° C. The esterification reaction time was 4-6h.

US 6,686,399 B1 (2004) describes the production of an alkyd resin produced by depolymerising PET with pentaerythritol containing a small amount of ethylene glycol. In the first step, ethylene glycol, pentaerythritol and soya fatty acid (S-fa) were charged and heated to melt. Post-consumer PET and the tin-based catalyst were added to the molten mixture and then heated to 230 ° C. This temperature was held for 2 h until the reaction mixture was clear. In the next step, phthalic anhydride, refluxing xylene and the rest of the S-fa were added to the product. It was heated (240 ° C) for a period of 3h until it reached the desired viscosity and formed the alkyd resin.

It is noted that despite the advances in the chemical recycling technique of PET for application in the coating industries, there is still a need to decrease the synthesis time of alkyd resin in order to provide shorter production times and less process water generation.

In this proposal, part of the polyacid to be consumed in the synthesis of the alkyd resin was replaced by polyester, PET, from post-consumer carbonated beverage bottles or not. We have also sought to vary the process parameters of the alkyd resin synthesis in order to decrease the reaction time at the lowest possible cost.

Broadly, the present invention relates to a process for obtaining synthesized alkyd resin by inserting poly (ethylene terephthalate), PET1 from post-consumer or non-consumed packaging, specifically through the chemical recycling process of PET.

The syntheses were performed under inert atmosphere and stirring. To perform the synthesis of the alkyd resin, the triglyceride soybean oil was first converted to di- and monoglyceride. This first reaction is called alcohololysis and is processed by reacting the vegetable oil with a

polyalcohol in the presence of a catalyst. At the end of the alcoholysis phase, preparation of the reaction medium is started to receive the remaining reagents and then to the esterification sand to form the alkyd resin.

(a) provide post-consumed PET feedstock with moisture content in the range 0.01 to 1% and intrinsic viscosity, V.I., in the range: 0.84 - 0.70 g / dL for blown feedstock; 0.63-0.70 g / dL for fibers; 0.72 to 0.84 g / dL for virgin PET; 0.46 to 0.76 g / dL for post-consumption PET;

b) Alcoholizing the vegetable oil in the presence of an ecatalyst polyalcohol under agitation and inert atmosphere;

(c) The temperature of the reaction medium for the alcohololysis phase of vegetable oil is 220-270 ° C;

d) After 20-60min, the solubility analysis in methanol is performed to monitor the alcohololysis reaction;

e) In the esterification step the reaction medium is cooled to 170-210 ° C for addition of the other reagents.

f) Addition of PET and temperature rise to 220 ° -260 ° C for 5-30 min.

g) After melting the PET, the temperature is lowered to 160-200 ° C and then the polyacid and also the refluxing solvent are added.

h) Heating the reaction medium to 200-230 ° C and after 60min of esterification, the first acidity index analysis is performed.

i) After reaching the desired acidity and viscosity index, the system is cooled to 180 ° C and dilutes the reaction medium with the appropriate solvent. DETAILED DESCRIPTION OF THE INVENTION

The aspect of the invention is therefore a process of obtaining post-consumer PET-based alkyd resin. Specifically, the use of PET was improved for the production of alkyd resin for application in the coating industry for the manufacture of varnish and alkyd paint with a decrease in alcoholic time from the use of specific catalyst and reaction process optimization.

For the invention, the following parameters are considered: catalyst, process temperature, nitrogen flow, refluxing solvent and process water generation.

The process of the invention may be included in the methods of obtaining alkyd deresine from the chemical recycling of PET, post-consumer or not. Synthesis of alkyd resin that was based on the process via alcoholysis and esterification for alkyd resin synthesis, which has been modified to allow the use of post-consumer PET.

The synthesis comprises the following alcoholization steps:

1) Nitrogen flow should be controlled at 60-70 bubbles / min and vigorous agitation;

2) Soybean oil is added and heating is started;

3) Next, the glycerol is added, continuing to warm the reaction until the temperature reaches 130-180 ° C, specifically between 140-160 ° C;

4) The catalyst (0.05-3.00% w / w) is added when the reaction medium reaches 140-160 ° C;

5) The temperature of the reaction medium is increased to 220-270 ° C, preferably 230-250 ° C, maintained for 20-60min;

6) After 20-60min, solubility analysis in methanol is performed to monitor the alcohololysis reaction;

The synthesis also comprises the esterification steps, as follows:

7) After alcoholization is complete, ie after the reaction product is tersolubilized in methanol, the reaction medium is cooled to 170-210 ° C for addition of the other reagents.8) Addition of PET (1-40% w / w) and temperature rise to 220 ° -260 ° C for 5-30 min.

9) After melting of PET1 the temperature is lowered to 160-200 ° C and then phthalic anhydride is added and also xylene for reflux.

10) Heat the reaction medium to 200-230 ° C. The reaction medium should be heated, as the reactants when added are at room temperature and therefore an initial drop in temperature occurs.

11) After 60min of esterification, acidity index analysis is performed. At the beginning of esterification, the acidity index should be followed every one hour and when approaching the desired value the analysis should be performed every 30 minutes.

12) After reaching the desired acidity and viscosity index, the system is cooled to 180 ° C and dilute the reaction medium with solvent.

13) Go through a filtration process before storage.

Analyzes for reaction monitoring

During the alcohololysis reaction triglyceride fatty acids (vegetable oil) are transformed into alcohols (monoglycerides, diglycerides), however there is no internationally standardized evaluation method for the evaluation of the alcohololysis reaction due to the individual character of each formulation (composition and process). ). Generally, the analysis is based on empirical methods, proven by practical tests (Verona, CC.Master dissertation: Study of the impact of the resin resins on paint properties. Federal University of Rio Grande do Sul. Advisor: José Luis Duarte Ribeiro, 2004).

The methanol solubility test, which aims to verify the increase of alcoholic functional terminations present in the reaction medium, allows the monitoring of the alcohololysis reaction. The test is based on the principle of solubility of methanol in oil and solubility of it in monoglyceride.

The triglyceride form of the oil is not directly reactive in esterification reactions as it has no free carboxylic or hydroxyl functionality. Thus, the formation of reactive hydroxyl groups can be followed, which serve to incorporate the grease fraction into the forming polymer chain and make make the polyacid soluble in the medium as it is not soluble in oil.

The completed alcohololysis reaction is considered after the sample has reached 1: 3 solubility in methanol. The test identifies the amount of alcohols (monoglyceride and diglyceride) in the mixture by visual identification as defined below: 2 mL of reaction sample is removed and added to a 10mL flask; Add to this sample 6mL of methanol; Stir the sample for 1 min and observe the behavior of the mixture.

> If the final solution becomes cloudy and with phase separation, the reaction product will fail, ie it has not reached the reaction end point. Turbidity indicates the saturation of the reaction medium with triglycerides. Oil triglycerides are not soluble in methanol;

> If the final solution becomes slightly turbid and without phase separation, the final product will be approved, ie the alcoholysis reaction has already reached the desired degree of conversion and may continue the synthesis with the esterification reaction.

> If transparent solution, approved product. Transparency indicates that the amount of alcohols formed in the reaction medium is already in the desired concentration for esterification.

The acidity index analysis of the forming polymer is performed in order to accompany the esterification reaction, in which the carboxylic functionality (acid medium origin) is consumed for the formation of the ester product. The acidity level of the reaction product is indicative of the degree of conversion or polymerization achieved until the time of analysis. The results of this analysis provide relevant data for sequence decision making or reaction completion.

The acidity index of an alkyd resin is determined according to international standard ASTM D1639 (1994) by titration. For this analysis standard 0.1 N KOH solution, phenolphthalein indicator 1% alcoholic solution and xylene / ethyl alcohol solvent 1: 1. About 1 g of the reaction medium are sampled during the esterification phase and added to Erlenmeyer. The sample is dissolved in 20 ml of the xylene alcohol solution, 3 drops of phenolphthalein are added and the KOH solution is triturated to the tipping point (colorless to pink solution).

Considering the stoichiometry of the acid-base reaction involved in this titration, the acidity index is calculated according to Equation 1.

<formula> formula see original document page 13 </formula>

Where la = acidity index (mg KOH / g solids); V = volume of spent KOH (mL); C = KOH concentration (normality); ma = mass of sample (g).

The expression of the acidity index calculation given in Equation 1 already considers the appropriate units and conversion factors for this form of expression.

The invention will be illustrated below by Examples which are not to be construed as limiting.

EXAMPLES

The formulations cited in this paper were based on information mainly from the literature, however modifications were necessary to obtain a post-consumer PET-based end product within the alkyd resin specifications for use in coatings (Patton, T.C..

Alkyd Resins Technology: Formulating Techniques and Alleid Calculations. New York-London, John Wiley and Sons Publishing House, 1962; Fazenda, R .. Paints and Varnishes: Science and Technology, Vol 1. Publisher: ABRAFATI. 1993).

Example 1

In the first phase, the reactor containing nitrogen flow of 60 bubbles / min and the stirring was charged with 23.73% w / w soybean oil and 12.80% w / w glycerol. The system was slowly warmed to room temperature. 150 ° C and 0.20% w / w zinc acetate is added. After addition of the catalyst the medium was heated to 240 ° C and maintained under these conditions until the dealolysis reaction was completed. In this phase, methanol solubility analysis was performed to monitor the alcohololysis reaction. The alcohololysis reaction took 60min to complete.

In the second phase of the reaction the temperature was lowered to 200 ° C, the 5% w / w PET was added and the medium was reheated to 240 ° C and left under these conditions for 15min. The temperature was lowered to 200 ° C and 19.31% w / w phthalic anhydride and some xylene were added for reflux.

The temperature was gradually raised to 200 ° C and these conditions were maintained until the desired acidity index was reached. At the end of the esterification reaction, the medium was cooled to 180 ° C, diluted with 38.96% w / w xylene and filtered for later storage. Esterification reaction take place 6h.

Example 2 and 3

Same procedure as in Example 1 using as catalyst 0,20% w / w lithium hydroxide (Example 2) and solution of 0,5% w / w lithium octoate at 0,20% w / w (example 3). It took 1h of alcohololysis to complete the synthesis using lithium hydroxide and the esterification reaction occurred in 5h. For synthesis with lithium octoate solution the alcoholization time was 30 min and the esterification time was 4h.

Example 4

Same procedure as in the first phase of Example 1 using a 1.5% w / w lithium octoate solution as a catalyst at a concentration of 0.20% w / w. The alcoholization time was 30min. In the second phase of the reaction the temperature was decreased to 200 ° C. 10% w / w PET was added and the medium heated again to 230 ° C and left under these conditions for 15 min. The temperature was lowered to 200 ° C and 14.31% w / w anhydridophthalic was added and slightly of xylene for reflux. The temperature was gradually raised to 205 ° C and these conditions were maintained until the desired acidity index was reached. At the end of the esterification reaction the medium was cooled to 180 ° C, diluted with 38.96% w / w xylene and filtered through for later storage. 3h esterification time.

Example 5

Same procedure as in the first phase of Example 1 using a 1.5% w / w lithium octoate solution as a catalyst at a concentration of 0.20% w / w. The alcoholization time was 30min. In the second phase of the reaction the temperature was lowered to 200 ° C, 15% w / w PET was added. The medium was reheated to 240 ° C and left under these conditions for 15 min. The temperature was lowered to 200 ° C and 9.31% w / w anhydridophthalic and a little refluxing xylene were added. The temperature is gradually raised to 205 ° C and maintained under these conditions until the desired acidity is achieved. Upon completion of the esterification reaction the medium was cooled to 180 ° C, diluted with 38.96% w / w xylene and passed through. filter for later storage. 2h30min esterification time.

COMPARATIVE EXAMPLE

To the reactor was added 23.73% w / w soybean oil and 12.80% w / w deglycerol and the system was heated to 150 ° C to add 0.20% w / w lithium octoate (1 0.5% w / w). The reaction medium was slowly warmed to 240Â ° C and these conditions were maintained until the completion of the alcoholysis reaction (methanol desolubility analysis, 30min). In the second reaction phase the temperature was reduced to 200 ° C and 34.31% w / w phthalic anhydride and a xylene poucode were added for reflux. The temperature was gradually raised to 200 ° C and these conditions were maintained until the desired acidity index was reached. At the end of the esterification reaction the medium was cooled to 180 ° C, diluted with 38.96% w / w xylene and filtered through for later storage. 9h esterification time. Examples 1 to 3 show formulations that differ by catalyst type. The objective was to test with which catalyst the lesser alcohololysis times of the vegetable oil would have occurred. When comparing the three catalysts, it was found that the lithium octoate catalyst achieved better performance with shorter reaction times. In all syntheses that used 0.20% w / w lithium deoctoate (1.5% w / w), the same alcohololysis time (30 min) was observed.

The lithium octoate catalyst (1.5% w / w catalytic solution) showed a high efficiency and exceeded the standard alcoholization time observed in the literature, which was around 60min of process.

Zinc acetate catalyst provided long reaction times (60min). The syntheses processed with lithium hydroxide also did not present good results of alcohololysis, that is, even increased catalyst reactions did not reach a desired derating time, which was initially the same obtained in the literature (60min).

Oil length is an important variable in the formulation of the orchid resin. The progressive decrease in the amount of oil contributes to a three dimensional increase of the polymer. The low oil level in the resin produces a polymer with high hardness and viscosity, but low elasticity, solubility and adhesion. The shorter oil length enables greater post-consumer PET incorporation, so larger amounts of PET are recycled.

The length of the oil is related to the amount of oil used in the formulation. For this work, formulations were adopted which produced short alkyd resins in oil. Short oil resins utilize higher amounts of polyacid, and consequently have greater use of post-consumption PET.

The form of agitation used in the syntheses is of great importance with regard to reaction conversion. Agitation is responsible for promoting greater contact between the immiscible synthesis reagents (oil spills and glycerol). The agitation process accelerates alcoholysis and the esterification reaction by causing shocks between the reactant molecules. Stirring was done mechanically and by inert gas insufflation into the reaction medium. The gasiner is responsible for removing possible air contamination initially in the reaction (the presence of O2 can cause decor development by oxidation) and promote better removal of products released during sanding, such as water.

According to Patton (Patton, T.C. Alkyd Resins Technology:

Formulating Techniques and Alleid Calculations. New York-London1 Publisher JohnWiley and Sons, 1962.) Inadequate agitation (agitation speed <10 ft / s) leads to long reaction times and low quality resins.

In this process, besides the removal of water by the inert gas

In the reaction medium, the carrier solvent also assisted in this removal, in which it formed an azeotropic mixture with water, to accelerate its removal from the meioreaction. The "solvent" process increases the reaction rate and assists in the reduction of phthalic anhydride loss by sublimation. Thus the solvent process was chosen for the synthesis of PET based alkyd resins.

The esterification reaction was controlled by the acidity index of the major reaction. Initially there are higher acidity values due to the presence of polyacid. During the reaction, the polyacid is consumed and the medium becomes less acidic (lower acidity). The esterification time is directly influenced with the acidity value, due to this variable to determine the end of synthesis.

The syntheses were conducted to have resin acidity index values around 5mgK0H / g. The resin synthesized in example 3 (5% PET) had an esterification time of 4h while the resin synthesized in example 4 (10% PET) the time was 3h. The esterification time of the synthetic resin synthesized in example 5 (15% PET) was only 2h30min.

The inclusion of post-consumption PET in the alkyd resin decreased the esterification time and therefore the total synthesis time. Alkyd resins containing 15% m of PET were synthesized in 2h30min as described above (esterification reaction) while the standard resin took 9h. esterification This result generates energy savings due to the reduction of the process time. During the synthesis of the alkyd resin there is the formation of the byproduct water, which is generated due to the polycondensation reaction of the esterification phase. This formed water needs to be removed from the process for sandstone to be converted, shifting its equilibrium to form more product. Water withdrawn from the process must be treated before disposal.

The addition of post-consumer PET to the alkyd resin led to a decrease in water formed as shown in Table 1.

Table 1. Amount of water generated during alkyd resin synthesis.

<table> table see original document page 18 </column> </row> <table>.

Table 2. Characterization of alkyd resin

<table> table see original document page 18 </column> </row> <table> Another aspect of the invention is the manufacture of varnish or paint obtained from alkyd resins synthesized with the process of the invention, whose general characteristics include percentage of non-volatiles 0-70%, viscosity U-Z6 and acidity from 3 to 25mg KOH / g resin.

Still another aspect of the invention is the article of manufacture obtained from the varnish or paint applied on metallic or non-metallic artifacts that require weather protection.

Claims (3)

1. Process for obtaining poly (ethylene terephthalate) PET1 alkyd resin from post-consumer packaging, characterized in that it comprises the following steps: (a) using post-consumed PET raw material in the form of flake or not, intrinsic viscosity, VI, in the range: 0.84 - 0.70 g / dL for raw materials; 0.63-0.70 g / dL for fibers; 0.72 to 0.84 g / dL for virgin PET; 0.46a 0.76 g / dL for post-consumer PET (b) Use inert gas flow between 60-70 bubbles / min (c) Process of alcoholization of vegetable oil using the lithium octoate catalyst 0.05 -3.00% w / w; d) Process of alcohololysis of vegetable oil with reaction medium temperature between 220-270 ° C for 20-30min; e) Process of chemical recycling of PET by glycolysis reaction of DOP at temperature of 220 ° C. ° -260 ° C for 5-30 min.f) Addition of PET in the amount of 1-40% m / mg) Process of esterifying the PET oligomers with the polyolepid alcohol with reaction medium temperature up to 200-230 ° C. Varnish or paint obtained from the process synthesized alkyd resins of the invention, the general characteristics of which include a non-volatile percentage of 0-70%, a viscosity of U-Z6 and an acidity of 3 to 25mg KOH / g resin. 3. Article of manufacture obtained from the varnish or paint applied on metallic or non-metallic articles requiring weather protection.