RO128212B1 - Oligoester plasticizers for pvc and process for preparing the same from wastes of polyethyleneterephthalate - Google Patents

Abstract

The invention relates to plasticizers for PVC and to a process for preparing the same. According to the invention, the plasticizers comprise, in molar percentage as compared with the acid component, 50...75% terephthalic structural units, 25...50% structural units as derivatives of dicarboxylic or polycarboxylic acids, aliphatic or aromatic acids, and 20...52% ethylene glycol structural units as compared with the diol component, and 48...80% structural units of linear or branched aliphatic monohydroxyl alcohol, as compared with the total alcoholic component. The process claimed by the invention consists, in a first stage, in the alcoholysis of PET wastes with monohydroxyl alcohols, in the presence of esterification-transesterification catalysts, at 180...220°C and atmospheric pressure, for 2...4 h, esterification of some dicarboxylic or polycarboxylic acids, aliphatic or aromatic acids or anhydrides with the product resulting from the first stage, at 140...180°C and atmospheric pressure, for 2 h, esterification of the resulting products with monohydroxyl alcohols, at temperatures of 180...250°C, for 4 h, and distillation of free alcohols with increase of molecular mass, by applying a vacuum of 50 mmHg for 1...2 h, at a temperature of 250°C.

Description

The invention relates to oligoesteric plasticizers for vinyl polychloride, PVC, and to a flexible process for obtaining them, starting from polyethylene terephthalate waste, PET, as a raw material.

Polyethylene terephthalate is an aromatic polyester with excellent thermal and mechanical properties, and remarkable chemical properties, used in quantities of millions of tonnes per year, among others, in the manufacture of packaging, in particular, bottles for food and non-food liquids. The widespread use of this polymer and the fact that it is not biodegradable creates huge amounts of waste. Therefore, a key problem in recent years is the conversion of PET waste into reusable materials. PET recycling is also important for the conservation of oil resources. Numerous methods of PET recycling are known. Among them, chemical recycling has been intensively investigated in recent years, being, to a large extent, consistent with the principles of sustainability. The chemical structure of the PET chain can be modified using suitable comonomers so as to result in oligomers with chemical structure and directed properties.

In the context of friendly interaction with the environment, a great interest is also present in the manufacture of environmentally friendly, non-toxic materials. In this respect, the regulations of the European Parliament and of the Council of Europe already prohibit the use of six monomer phthalates (phthalic acid diesters), namely: di- (2-ethylhexy I) phthalate, di butyl phthalate, benzyl butyl phthalate, di-n- octyl phthalate, di-isodecyl phthalate, di-isononyl phthalate, as plasticizers for PVC, in concentrations greater than 0.1%, in the manufacture of toys and other articles for the care of children, as well as in the manufacture of medical articles, existing , further, concerns about restricting their use. This created the need to increase efforts to replace them with other compounds, which have similar performance properties, do not migrate to the environment and are cheap.

In this context, it has been found that, through the chemical destruction of PET waste, it is possible to obtain compounds with bis-ester structure, which can be used as plasticizers for PVC processing.

The obtaining of plasticizers by the chemical destruction of PET is cited in US 5101064 and US 5319128 (Dupont, et al.), Which describe the obtaining of terephthalic acid diesters by PET alcoholization, in the presence of various alcohols with high molecular weight.

Although these compounds do not contain crimped o-phthalic acid, their ability to migrate into the environment is somewhat similar to that of o-phthalic diesters, being monomeric esters of the same molecular mass as that of the corresponding o-phthalic diesters.

US Patent 5068395 (Bathe) discloses a process for the preparation of polyester plasticizers by chemical destruction of PET waste, in the presence of trimelitic anhydride esters with a polyol with molecular weight 60-650 and a linear alcohol with 8-10 carbon atoms. , previously obtained.

The resulting copolymer, containing terminal hydroxyl groups, is then reacted with a 12-18 carbon atom.

However, the process described is quite complicated (involves the use of a large number of raw materials and synthesis stages) and expensive.

Kilinc, S.; lyim, T. B.; Emik, S.; Ozgumuș, S. Polimer, Plastics Technology and Engineering. 2005, Volume 44, Numbers 8-9, describe the obtaining of a polyester plasticizer for PVC, by depolymerizing polyethylene terephthalate with ethylene glycol in the presence of catalyst, zinc acetate. The reaction product, with high content of terminal hydroxyl groups, was reacted with adipic acid in equivalent amount. The process leads to the obtaining of secondary plasticizers, usable, in combination with di-octylphthalate, to the PVC laminating.

RO 128212 Β1

The product obtained is a polymer (aliphatic-aromatic copolyester), with terminal groups 1 hydroxyl or carboxyl, which does not contain in the chemical structure structural units of Chil Ice with high molecular weight (C8-C10), in end-chain or side-chain positions, which can print 3 plasticizer to certain specific properties.

The technical problem that the invention solves consists of: obtaining oligoesters 5 usable capiastifiers in PVC processing, presenting the chemical structure and molecular mass directed according to the performance properties, followed for the specific applications of the 7 PVC compound, assures the PVC which- l incorporates physical-mechanical properties similar to those printed by the consecrated plasticizers and has the reduced tendency of migration compared to 9 diphtyl phthalates, in the international context of the restrictions imposed on the latter; performing a flexible synthesis process, designed to provide the respective oligoesters with a controlled chemical structure and estimated molecular mass, depending on the performance characteristics of the PVC embedding, and which, at the same time, constitute a process of 13 chemical recycling of polyethylene terephthalate waste.

The oligoester plasticizers, according to the invention, remove the disadvantages mentioned above 15, in that they consist of: 50 ... 75%, molar percentage of total acid component, terephthalic structural units, coming from polyethylene terephthalate, PET; 17

25 .. .50%, molar percentage of total acid component, structural units derived from other dicarboxylic or polycarboxylic acids, aliphatic or aromatic; 20 ... 52%, molar percentage compared to 19 of total diol component, ethylene glycol structural units from polyethylene terephthalate, PET; 48 ... 80%. molar percent of total alcohol component, 21 structural units of monohydroxyl, aliphatic, linear or branched alcohols. They have a directed chemical structure and molecular mass, depending on the performance properties, 23 tracked for specific applications, have a hydroxyl index <12 mg KOH / g and an acidity index <5 mg KOH / g and print to the compound. vinyl polychloride, PVC, 25 specific physical-mechanical properties, such as Shore A hardness, elongation at break, tensile strength at break, elongation at tear comparable or higher compared to 27 consecrated plasticizers, under the same processing conditions, have tendency of reduced migration and come from polyethylene terephthalate waste, PET. 29

The process of obtaining oligoesteric plasticizers for vinyl polychloride, PVC, according to the invention, is carried out in several stages consisting of: (1) the alcoholization of waste 31 bottles of polyethylene terephthalate, PET, with high molecular weight aliphatic monohydroxyl alcohols, with linear or branched chain, at an alcohol: PET 33 molar ratio

1 .. .1.2: 1, depending on the degree of cleavage of polyethylene terephthalate, in the presence of esterification-transesterification catalysts in the proportion of 0.05 ... 0.3% molar compared to the total 35 acids, at 18O temperatures ... 22 ° C and atmospheric pressure, a time of 2 ... 4 h; (2) esterification of aliphatic or aromatic di- or polycarboxylic acids, added or derived thereof, 37 selected from anhydrides, with products! obtained in step (1), at an acid molar ratio:

PET of 0.4 ... 1: 1, at temperatures of 140 ... 180 ° C and atmospheric pressure, for two hours, 39 until an acidity index corresponding to complete esterification of a carboxyl functional group is reached; (3) esterification of the products obtained in step (2) with 41 aliphatic monohydroxyl alcohols with its branched linear chain, at a molar ratio of monohydroxyl alcohol: di- or polycarboxylic acid of 0 ... 1,7: 1, at temperatures of 180. ..250Ό, for four hours, up to 43 distillation of the stoichiometric quantity of water resulting from the esterification reactions, and (4) distillation of the non-esterified free alcohols and increasing the molecular mass by applying a maximum vacuum45 of 50 mm Hg, for 1 ... 2 h, at 250 ° C, until a hydroxyl index <12 mg KOH / g is reached and an acidity index <5 mg KOH / g.47

RO 128212 Bl

The process for obtaining oligoesteric plasticizers according to the invention has monohydroxyl, aliphatic alcohols, used for the alcoholization of polyethylene terephthalate waste and, optionally, for the complete esterification of di- or polycarboxylic acid modifiers, which are selected from: n-hexaneol , n-decanol, 2-ethylhexanol, isononanol, isodecanol or mixtures thereof; esterification - transesterification catalysts are preferably selected from tetraisopropyl or tetrabutyl titanate or tin oxide; the di- or polycarboxylic acids are selected from adipic acid, italic anhydride, trimelitic anhydride or mixtures thereof.

The advantages of applying the invention in relation to the prior art consist in the achievement of the following;

- diversification of the production of plasticizers for PVC processing;

- the reduction of the costs with the raw materials, by using a significant quantity (25 ... 50% gravimetric from the final composition of the oligoesteric plasticizer) of polymeric waste (PET);

- the development of a flexible technology, which allows to obtain products with a controlled chemical structure, thus leading to obtaining certain properties of the final products, depending on the performance characteristics required for the specific application of the PVC compound;

- developing a technology for recycling a polymeric waste (PET) that accumulates in very large quantities and is not biodegradable;

- reducing the consumption of raw materials from petroleum processing.

The content of the invention is described in detail below.

In terms of consumption, PVC is one of the most important plastics available, which can acquire, by mixing with different additives, a wide range of physical, chemical and mechanical properties, useful in many applications, ranging from packaging to medical devices, toys, building materials, electrical cable insulation, clothing or furniture.

The selection of the optimal plasticizer for use in a particular application is guided by economic criteria, toxicological regulations, ease of processing and performance in the finished product.

The key performance properties of the plasticizers are depending on the plasticizer concentration (%) and the chemical structure.

The chemical structure, molecular mass and molecular architecture of the plasticizer affect the properties of the mixture; thus, changes in the estimation of the plasticizer structure can be used to modify the performance of the final material.

The different plasticizers will have different characteristics both in the ease with which they form the plasticized material, as well as in the mechanical and physical characteristics resulting from the flexible product, due to the differences in the strength of the plasticizer-polymer or plasticizer-plasticizer interactions.

Such effects can be illustrated in the following examples:

- In PVC seals for refrigerators, plasticizers suitable for low temperature and which have a controlled migration are used, to avoid microfissuring the inner part (the lining) of the PVC doors;

- for electric cables, the plasticizer selection depends on the performance of the insulating material, so the products used at higher temperatures require the use of a plasticizer with better permanence properties;

- Plasticizers that melt at low temperatures improve the processability and stain resistance of vinyl floor coverings or protect the fibers that make up certain types of carpets or carpets, due to volatilization;

RO 128212 Β1

- products designed for outdoor use will require plasticizers with a better 1 permanence;

- the molded products used for the car interiors will use plasticizers resistant to 3 extraction in water, due to the performances of resistance to steam, required by the manufacturers;

- Adhesives and sealing agents generally use plasticizers with improved solvency 5 and lower melting temperature.

For a plasticizer to be effective and useful in PVC, it must contain two types of 7 structural units, polar and non-polar. The polar portion of the molecule must be capable of reversibly binding to the PVC by softening it, while the nonpolar portion of the molecule allows the control of the interactions so that the plasticizer is not such a strong solvent that it destroys the crystallinity of the polymer. . The balance between the polar and nonpolar portions of the 11 molecule is critical for controlling the solubilization effect.

Examples of polar components may be carbonyl groups of ester functions and, to a lesser extent, aromatic nuclei; the nonpolar portion may be an aliphatic side chain of an ester or polyester. 15

Highly solvent plasticizers have higher polarity and / or aromaticity.

Plasticizers with improved low temperature properties are less than 17 solvents and have higher diffusivity, have a low polarity chemical structure (small polar / nonpolar structural units, are generally aliphatic) 19

Aliphatic dibasic esters have exceptional low temperature properties. Alcohol with a lower molecular weight is used with acids with a higher molecular weight, and vice versa, 21 so that the total carbon / molecule content is in the range C ₁₈ - C ₂₆ . This range maintains the non-polar / polar ratio required to ensure compatibility with 23 PVC, along with its properties at low temperature. Linear alkyl structures lead to low temperature performances as well as low volatility, while branched 25 alkyl structures are used in low temperature applications that require lower diffusivity.

On the negative side, low temperature plasticizers have a low compatibility 27 for PVC and a high loss due to diffusion in the finished products.

Plasticizers with low volatility generally have large molecular masses, which is also reflected in the low vapor pressure. On the contrary, plasticizers with low molecular weight are more volatile. In some cases, for example, in the case of phthalates, the increase of 31 molecular mass increases the ratio of nonpolar / polar functionalities, until the appearance of compatibility with higher molecular masses decreases. 33

Two chemical families are used as plasticizers with low volatility: trimels and polyesters. 35

Highly solvent plasticizers have poor diffusivity, due to the strong interactions with the polymer matrix. Poor diffusivity is also determined by the 37 large molecular mass and the strongly branched isomeric structure.

The higher the viscosity of the plasticizer, the higher its permanence is 39.

The polarity or O / C ratio also influences the extraction resistance of 41 compoundurilorpolymerics. The materials with lower polarity have a better resistance to polar fluids, such as soap water. 43

The polyester blenders confer, in addition to low volatility, low diffusivity and stability. 45

The process of synthesis from polyethylene wastes made of oligoester plasticizers for PVC, described by the present invention is an alcohol-esterification process in 47 melts.

RO 128212 Bl

For the physico-chemical and structural characterization of the oligoesters obtained according to the invention, the following methods were used:

- the acidity index (l _A ) of the oligoesters was determined according to ASTMD-4662 -98;

- the hydroxyl index (1 _oh ) of the oligoesters was determined according to ASTM-D4274;

- the water content (%) was determined by the Karl - Fischer method, according to ASTMD4672-05.

The dynamic viscosity of the oligoesters was determined on a rotary viscometer with coaxial cylinders, type Rheotest 2, at 25 ° C and, if necessary, at 50 ° C, at different shear gradients; from the determined values, the average dynamic viscosity (n) was calculated.

The ¹ H-NMR and sample spectra were recorded on a Varian Gemini 300 spectrophotometer with superconductor magnet.

Column chromatography

The plasticizer samples obtained were separated by silica gel column chromatography, eluents petroleum ether: methylene chloride = 4: 1, ethyl ether: methylene chloride = 1: 1.

For the physico-mechanical characterization of the PVC samples containing plasticizers obtained according to the invention, the following determinations were used:

- Shore A hardness, on specimens cut from plates of at least 6 mm thick, with Shore A durometer, according to STAS 868/1995;

- thermal stability at 180 ° C, with Congo Red, according to STAS 182-1 / 1998;

- loss of plasticizer by volatilization at 70 ° C with activated carbon, on disc-shaped specimens, with a diameter of 50 mm ± 1 mm and a thickness of 1.0 mm ± 1 mm, according to STAS 176/2000;

- breaking extension, tensile strength and tensile strength were determined using the INSTRON physical-mechanical test apparatus, the test speed of 200 mm / min, on type II tests, according to STAS 527-1 / 2000 and 527-2 / 2000.

The following are six examples of the realization of the oligoesteric plasticizers obtained by the process according to the invention.

Example 1. In a polycondensation autoclave made of stainless steel, with a capacity of 1000 cm, provided with a heated defilter jacket with electric resistors, with a temperature regulator, a stirring anchor with a speed of 60 ... 70 rpm, connection to the atmosphere inert, temperature recorder, pressure gauge, upstream / downstream refrigerant system partially reflux, stainless steel, connected to a distillate collection vessel, connected to the vacuum pump, loaded: 156 g (1.2 moles) 2-ethylhexanol (2-EH) - commercial product and 0.81 g - 0.65 ml (0.1% molar to total acids) octane tin - commercial product, catalyst. The heating was started in the bottom refrigerant mantle, up to a temperature of 100 ... 120 ° C and, under an inert atmosphere (nitrogen), the reaction mass was heated to 100 ° C, when 192 g (1 mol) was charged ethylene terephthalate (PET) pole waste from cut-off cylinders, with grain size ~ 5/5 mm, with the following main physico-chemical characteristics: molecular mass ~ 40,000, melting range 254 ... 260 ° C, l. _0H , 2 , 5 ... 3 mg KOH / g and humidity <0.2%.

Under an inert atmosphere (N ₂ ), the temperature was raised and kept for three hours at

180 .. .200'C, total reflux. After lowering the temperature to 140 ° C, 148 g (1 mol) phthalic anhydride (AF) - commercial product was introduced. A temperature of 140 ... 180'0 was maintained for two hours until an acid mass index of 115 mg KOH / g was reached. Add 156 g (1.2 moles) 2-ethylhexanol (2-EH) and continue heating to

180 .. .250'0, for three hours, when about 15 ml of water and 4 ml of distilled 2-ethylhexanol are distilled, the acidity index of the reaction products being about 15 mg KOH / g. A progressive vacuum of up to 50 mm Hg was then applied for one hour, maintaining the temperature at 250 ° C. 12.5 ml of water and ethylene glycol were mixed in vacuo and 33 ml of 2-ethylhexanol.

RO 128212 Β1

Approximately 570 g of final PI oligoester, a light brown-green liquid, was obtained. After evacuation, the oligoester was filtered through a 0.75 mm metal screen. The physico-chemical properties of the oligoester are presented in table 1. By corroborating the information 3 obtained by column chromatography and NMR spectroscopy separation of the oligoester sample, the following composition was highlighted: free alcohols: 1.5% molar compared to 5 total alcohols (ratio EG / 2-EH = 1 / 1,1, monomers: 18% molar to total acids (ratio approximately dioctyl phthalate / dioctylterephthalate = 1 / 1.5, dimers: 79% molarfetal acid, oligomers 7 higher: 3 % of total acids.

Example 2. The procedure described in Example 1 was repeated, with the exception that the alcohol 9 used for the PET alcoholization was n-decylalcohol, in the amount of 237.42 g (1.5 moles), the alcohol reaction was held at a temperature of 19O. At 22 ° C, for four hours, the catalyst for alcohololysis 11 was stannous octane, in the amount of 1.62 g -1.3 ml (0.2 molar% of total acids), the carboxylic acid modifier was trimellitic anhydride In the amount of 192 g (1 mol), the additional alcohol 13 added for the total esterification of the trimelitic anhydride was n-decylalcohol, in the amount of 269 g (1.7 moles), during the esterification reaction at atmospheric pressure. 15 distilled approximately 32 ml water and 7 ml n-decyl alcohol, and in the vacuum application stage, 13.5 ml of water and ethylene glycol were distilled and 19 ml n-decyl alcohol, 17

Approximately 780 g of final P2 oligoester, solid, light brown were obtained.

The physico-chemical properties of the oligoester are shown in table 1. 19

Example 3. The procedure described in Example 1 was repeated, with the exception that titanium tetraisopropoxide was used as catalyst in alcoholization in the amount of 0.5 g, 0.55 ml (0.1% 21 molar to total acids), the modifying carboxylic acid was adipic acid in the amount of 146 g (1 mol). During the esterification reaction of the first carboxyl group of the modifying acid, 17.5 ml of water and 4.5 ml of 2 - ethylhexanol were distilled. Additional 2-ethylhexanol added for the total esterification of adipic acid was 130 g (1 mol). During the atmospheric pressure esterification reaction of the second carboxylic group of adipic acid, about 15.5 ml of water and 3.5 ml of 2-ethylhexanol were distilled, and in the vacuum application stage, 27 s 12.5 ml of water and ethylene glycol and 17 ml 2-ethylhexanol were distilled.

Approximately 535 g of final P3 oligoester, a light brown liquid, was obtained. 29 The physico-chemical properties of the oligoester are presented in table 1.

Example 4. The procedure described in Example 1 was repeated, except that the carboxylic acid modifying 31 was italic anhydride, in the amount of 59.2 g (0.4 mol), no additional 2-ethylhexanol was added, and the esterification reaction of the second carboxyl group 33 of phthalic acid at atmospheric pressure led to the distillation of 6.5 ml of water and 1.5 ml of ethylated 2-ethylene hexane, and in the vacuum application step, 12 ml of distillate were distilled. water and 35 ethylene glycol and 32 ml 2-ethylhexanol.

Approximately 318 g of final P4 oligoester, solid, light gray-brown, were obtained. 37 The physico-chemical properties of the oligoester are shown in table 1.

Example 5. The procedure described in Example 1 was repeated, with the exception that, at 39 PET alcoholization, 143 g (1.1 moles) of 2-ethylhexanol was used, the catalyst used was titanium tetraisopropoxide in an amount of 1.19 g, 1.28 ml (0.3 molar% of total acids), 41 carboxylic acid modifier was adipic acid, in amount of 58.4 g (0.4 mol), the esterification reaction of adipic acid at atmospheric pressure proceeded in a single step, as 43 additional 2-ethylhexanol was no longer added and distilled 13 ml of water and 4 ml

Trained 2-ethylhexanol, and in the vacuum application step, 11 ml of water and 24 ml of 2- 45 ethylhexanol were distilled.

Approximately 312 g of final P5 oligoester, viscous liquid, light brown 47 were obtained.

RO 128212 Bl

The physico-chemical properties of the oligoester are presented in table 1.

Table 1

Oligoester code Oligoester structure l _A (mgKO H / g) Iqh (mgKO H / g) Humidity % Appearance at ambient temperature Π (cP) P 1 1o, s Fo, ₅ E o, ₂₉ EH _o , ₇₁ 4.8 10.7 0.0137 Light greenish brown liquid 950/25 ° C P2 T 0.5 ^ 0.5 0.5 E 0.24 DA ₀ , ₇₆ 4.9 9.8 0.0125 light brown solid 147 / SOC P3 I Ο, βδΑ 0.3 E 0.31 EH 0.69 4.7 10.2 0.0087 light brown liquid 750/25 ° C P4 T 0.7 | F 0.29 ^ 0.4sEH 0.55 4.1 11.9 0.0135 solid, light gray-brown 2350/50 ° C P5 T 0.71 'Ao, 2gE 0.4sEH 0.52 3.8 11.4 0.0092 viscous liquid, light brown 2560/25 ° C

T = terephthalic, F = phthalic, Tr = trimelitic, A = adipic, E = ethylene glycol, EH = 2-Ethylhexanol, DA = n-decyl alcohol.

Example 6. The oligoesters obtained by the procedures described in Examples 1, 2 and 3 were tested as plasticizers for PVC additives.

For testing the plasticizers, the dedicated recipe was used to obtain a plasticized PVC product, the product YT2, intended for the manufacture of footwear used in a temperate climate, presented in table 2.

Table 2

Nr. crt. Name of ingredient Quantity (g) 1. PVC kw 70 100 2. Dioctyl phthalate (DOF) 68 3. Stearic acid 0.40 4. Calcium stearate 0.60 5. Lead tribasic sulphate 2.80

Work was done with PVC k-wert 70. The behavior of processing new recipes was followed; weighed on the analytical balance, with an accuracy of 0.001 g, the quantities of additives according to their recipes.

The mixtures, consisting of PVC-S, stabilizers and plasticizers, were homogenized in a porcelain capsule, at room temperature and subjected to rolling on the laboratory roll, under the following conditions: cylinder temperature: 145 ... 150'0 ; screw speed: 30 rpm; friction coefficient: 1: 1; roll processing time: 5 min. 1 mm thick PVC film was obtained.

All the samples of PVC compound additives with the plasticizers obtained according to the invention showed a behavior corresponding to the processing on the laboratory roll.

The films obtained were characterized from the point of view of the physico-mechanical properties.

The test specimens were made of plates of different thicknesses. These plates were obtained, in the laboratory press, from the previously processed sheets on the laboratory roll, under the following conditions: pressing temperature: 160 ° C; preheating time: 3 ... 5 min; pressing time, depending on the thickness of the plate: 3 ... 5 min; cooling time from 160 to 50 ° C:

15 ... 30 min; working pressure: 250 atm.

From the plates obtained, the test specimens were cut.

The results of the testing of PVC plastic samples with oligoesters according to the invention, compared with samples obtained from DOF plasticized PVC, obtained under the same conditions and considered as a standard, are presented in table 3.

RO 128212 Β1

Table 3 1

Nr. test tube Determination (UM) \ Sample code Shore hardness A (Degrees) Thermal stability at 180 "C with Congo Red (min) Loss of plasticizer (%) Breaking extension (mm) Tensile strength (N / mm ² ) Stress resistance to breaking (%) 1 DOF (standard) 36.00 35 0.917 156.67 10.25 195.83 2 P1 31,50 39 0.672 184.44 14.95 230.56 3 P2 36.00 53 0.795 163.33 11.33 204.17 4 P3 32.00 54 0.884 201.11 10.43 251.39

The oligoesters according to the invention had similar physico-mechanical characteristics similar to or superior to dioctyl phthalate, and the losses of plasticizer were inferior to it. 13

Claims (4)

claims 1. Oligoesteric plasticizers for vinyl polychloride, PVC, characterized in that they consist of: 50 ... 75%, molar percent of total acid component, terephthalic structural units from polyethylene terephthalate, PET; 25 ..50%, molar percentage of total acid component, structural units derived from other dicarboxylic or polycarboxylic, aliphatic or aromatic acids; 20 ... 52%, molar percentage of total diol component, ethylene glycol structural units from polyethylene terephthalate, PET; 48 ... 80%, molar percent of total alcohol component, structural units of monohydroxyl, aliphatic, linear or branched alcohols. The oligoester plasticizers for vinyl polychloride, PVC according to claim 1, characterized in that they have an hydroxyl index <12 mg KOH / g and an acidity index <5 mg KOH / g. 3. Process for obtaining oligoesteric plasticizers for vinyl polychloride, PVC, characterized in that it is carried out in several stages, consisting of: (1) the alcoholization of food-bottle wastes from polyethylene terephthalate, PET, with molecular weight aliphatic monohydroxyl alcohols large, linear or branched chain, at an alcohol molar ratio: PET of 1,2: 1, depending on the degree of cleavage of the polyethylene terephthalate, in the presence of esterification-transesterification catalysts in the proportion of 0.05 ... 0.3% molar percentage of total acids, at temperatures 180 ... 220 ° C and atmospheric pressure, for 2 ... 4 h; (2) esterification of di- or polycarboxylic, aliphatic or aromatic acids or derivatives thereof, selected from anhydrides, with the products obtained in step (1), at an acid molar ratio: PET between 0.4 and 1: 1, latemperature from 140 ... 180 ° C and atmospheric pressure, for two hours, until an acidity index corresponding to the complete esterification of a carboxyl functional group is reached; (3) esterification of the products obtained in step (2) with monohydroxyl, aliphatic alcohols, with straight or branched chain, at a molar ratio monohydroxyl alcohol: di- or polycarboxylic acid of 0 ... 1,7: 1, at temperatures of 18O ... 25O ⁰ C, for four hours, until the stoichiometric amount of water resulting from the esterification reactions is distilled, and (4) the distillation of the non-esterified free alcohols and the increase of the molecular mass by applying a maximum vacuum of 50 mm Hg, during 1 ... 2 h, at a temperature of 250 ° Ο, until a hydroxyl index <12 mg KOH / g and an acidity index <5 mg KOH / g are reached. 4. Process for obtaining oligoesteric plasticizers according to claim 3, characterized in that the monohydroxyl, aliphatic alcohols, used for the alcoholization of polyethylene terephthalate waste, optionally for the complete esterification of the di- or polycarboxylic acid modifiers, are selected from: n-hexaneol , n-octanol, n-decanol, 2-ethylhexanol, isononanol, isodecanol or mixtures thereof; esterification - transesterification catalysts are preferably selected from tetraisopropyl or tetrabutyl titanate or tin oxide; these polycarboxylic acids are selected from adipic acid, phthalic anhydride, trimelitic anhydride or mixtures thereof.