PL189028B1 - Method of obtaining a polyester plasticiser - Google Patents

Abstract

1. The method of producing polyester plasticizers consists in carrying out polycondensation of a dicarboxyl acid, especially adipic acid, and/or an acid anhydride, especially phthalic anhydride, with glycol or a mixture of glycols, followed by esterification of the final groups by means of a monocarboxylic acid or a monohydric alcohol, while condensation water is educed and removed. It is characterised in that adipic acid, phthalic anhydride or their mixture are subjected to polycondensation with the glycol with the general formula HO-CH2-CR1R2-CH2-OH, where: R1 is different from R2; if R1 refers to a methyl group, R2 refers to an atom of hydrogen or an ethyl group; if R1 refers to an ethyl group, R2` refers to an n-butyl group; or else, R1 and R2 together refer to a cyclic group (CH2)5 and form a cyclohexane cycle with the central hydrogen atom in the general formula HO-CH2-CR1R2-CH2-OH. Or else, they are subjected to polycondensation with a mixture of the glycol with the general formula HO-CH2-CR1R2-CH2-OH, where R1 and R2 have the meaning defined above, with an ethylene glycol, diethylene glycol, neopentyl glycol, 1,4-butylene glycol, 1,2-propylene glycol or 1,3-propylene glycol. The mixture of glycols contains at least 5 percent (molar) of the glycol with the general formula HO-CH2-CR1R2-CH2-OH. The final groups of the resultant product are esterified, preferably with 2-ethylhexanol.

Description

The present invention relates to a process for the production of polyester plasticizers by polycondensation of a dicarboxylic acid or acid anhydride with glycols and end-group blocking by esterification. The main application of the polyesters obtained in this way is the plasticization of poly (vinyl chloride) [PVC].

Known methods for the production of polyester plasticizers, intended primarily for the softening of PVC, consist in the polycondensation of adipic acid or phthalic anhydride with glycols. As glycols, 1,2-propylene, 1,3-butylene, ethylene, 1,4-butylene or neopentyl glycol are used, either separately or in binary mixtures, for example ethylene glycol together with 1,4-butylene glycol. The end groups in the polyester are blocked by esterification with a monofunctional reagent; this blocking usually consists in esterification of carboxyl end groups with n-butanol or 2-ethylhexanol. During the polycondensation and esterification of the end groups, water is released, which is drained from the reaction medium. The molecular weight of the known polyester plasticizers is generally 1000-3000, especially around 2000.

The individual polyester plasticizers are characterized by a specific complex of properties, especially the plasticizers used to soften PVC. The following properties are of particular importance: plasticizer viscosity, PVC softening performance, thermal stability, volatility and resistance to extraction.

The aim of the invention was to develop a method for the production of polyester plasticizers, especially for PVC, characterized by the desired set of properties, especially low viscosity and high softening efficiency.

It has been found that the plasticizers polyester having the desired properties is achieved in such a way that, adipic acid, phthalic anhydride, or a mixture thereof is subjected to polycondensation with a glycol of the formula HO-CH2-CR1R2-CH2-OH, wherein R 1 and R ₂ are different and - if R1 is a methyl group, then R2 is a hydrogen atom or an ethyl group, and if R1 is an ethyl group, then R2 is an n-butyl group, or R1 and R2 together represent a ring group (CH2) 5 and together with the central carbon atom in by the general formula HO-CH2-CR 1-R2-CH2-OH form a cyclohexane ring. In the process according to the invention, glycols of the general formula HO-CH2CR1-R2-CH2-OH are also used in which R1 and R2 are as defined above, in a mixture with ethylene, diethylene, neopentyl, 1,4-butylene glycol, 1,2 -propylene or 1,3-propylene, the content of glycol of the general formula HO-CH2-CR1R2-CH2-OH in the glycol mixture is at least 5 mole%. For esterification of the end groups, preferably 2-ethylhexanol is used as the monohydric alcohol.

By central carbon is meant the C atom in the general formula HO-CH2-CR1R2 CH2-OH.

In the process according to the invention, the glycol of the general formula HO-CH2 CR 1R2-CH2-OH is most preferably used 2-methyl-1,3-propanediol or 2-ethyl-2-methyl-1,3-propanediol, especially in a mixture with glycol. ethylene or 1,2-propylene, or 2-butyl-2-ethyl-1,3-propanediol, especially in a mixture with ethylene or diethylene glycol, or 1,1-bis (hydroxymethyl) cyclohexane, especially in a mixture with neopentyl glycol or 1, 4-butylene.

Said glycols and glycol mixtures are subjected to polycondensation with adipic acid, phthalic anhydride or mixtures of these starting components in which the molar ratio of the amounts of adipic acid and phthalic anhydride is from 1:10 to 10: 1.

The polyester plasticizers according to the invention are intended for softening polyvinyl chloride as well as other polymers, especially copolymers of vinyl chloride with vinyl acetate or with vinylidene chloride.

The method of producing the polyester plasticizers according to the invention, using glycols of the general formula HO-CH2-CR 1R2-CH2-OH, in which R1 and R2 are as defined above, allows obtaining products with a wide range of properties. Depending on the chemical composition, e.g. low-viscosity liquid polyesters or different solid state polyesters are obtained. The polyester plasticizers selected from this group make it possible to obtain PVC plasticizers with the desired complex of properties, such as low brittleness temperature, favorable correlation between the plasticizer content and hardness (Shore), tensile strength, elongation at break and brittleness temperature.

Other advantageous properties are resistance to migration, for example to polystyrene, low volatility and thermal stability at elevated temperatures, and low water absorption.

A typical composition of PVC plasticizers using polyester plasticizers (in parts by weight) is as follows: PVC (100), polyester plasticizer (60-90), Ba-Zn stabilizer (1), stearic acid (0.4). In addition, the plasticizer may contain a mineral filler, such as chalk (up to 50). Part of the polyester plasticizer may be replaced with a liquid low molecular weight plasticizer, for example di- (2-ethylhexyl) phthalate, to facilitate processing.

The following examples illustrate the process of the invention and some of the possibilities it offers.

Example I. Adipic acid (217.7 g) and 2-methyl-1,3-propanediol (122.6 g) are heated at 180-200 ° C while distilling off water until the acid number is obtained

189,028 mgKOH / g. Then 2-ethylhexanol (67.5 g) was added and heated at 200-220 ° C while distilling off water and excess 2-ethylhexanol. The resulting polyester has an acid number of 2.0 mgKOH and a viscosity of 3.5-4.5 Pa.s at 23 ° C.

Example II. Phthalic anhydride (196 g) and 2-ethyl-2-methyl-1,3-propanediol (240 g) were heated at 180-200 ° C with distillation of water to an acid number of 15 mgKOH / g. Then, 2-ethyl-heptane carboxylic acid (86 g) was added and the mixture was heated at 200-220 ° C, distilling off water and excess acid. The obtained polyester has a viscosity of 7-10 Pa.s at 23 ° C.

Further examples of methods for making the polyester plasticizers of the invention are shown in Table 1; they are analogous to that described in example I.

Table]

Manufacture of polyester plasticizers

Example Acid adipic g Anhydride phthalic g Glycol 1 g Glycol 2 g 2-Ethyl- hexanol g Product properties Acid number mgKOH / g Viscosity at 23 ° C Pa.s III 227.8 - BEPD, 130.0 - 65 2.0 3.5 IV 292.0 - BHMC, 219.0 - 65 1.5 5.0 V - 250.0 MPD, DEG 40.0 75 3.0 8.0 VI - 225.0 BEPD, 136.2 EG, 53.4 60 2.5 9.3 VII 438.0 - BHMC- 292.0 NPG, 52.0 130 2.0 4.2

MPD: 2-methyl-1,3-propanediol

EMPD: 2-ethyl-2-methyl-1,3-propanediol

BEPD: 2-Butyl-2-ethyl-1,3-propanediol

BHMC: 1,1-bis (hydroxymethyl) cyclohexane

EG: ethylene glycol

DEG: diethylene glycol

NPG: neopentyl glycol

The chemical composition of PVC plasticizers containing the polyesters prepared in Examples 1-7 and some properties of these plasticizers are given in Table 2. All plasticizers were prepared using (in parts by weight) equal amounts of PVC (100), Ba / Zn stabilizer (1) and stearic acid (0.4). The amounts of plasticizers vary and are given in Table 2.

189 028

Table 2 PVC plasticizers

Example Polyester plasticizer, according to the example, parts by weight Di (2-ethylhexyl) phthalate, parts by weight Shorr A hardness Frost resistance, ° C .- .. Strength aa stretches- aie, MPa and_ Elongation at break, % Volatility at temperature 100 ° C Response to migration,% AND 40 15 79 -8 8.2 300 0.20 0.14 II 45 twenty 76 -10 8.7 300 0.26 0.34 III 45 twenty 77 -10 7.9 270 0.30 0.25 IV 40 25 56 -twenty 11.3 310 0.30 0.40 V 40 25 64 -twenty 12.5 290 0.25 0.32 VI 45 twenty 72 -15 9.1 254 0.20 0.20 VII 45 twenty 74 -10 8.6 230 0.15 0.15

189 028

Publishing Department of the UP RP. Circulation of 50 copies

Price PLN 2.00.

Claims (5)

Patent claims 1. Method for the preparation of polyester plasticizers by polycondensation of a dicarboxylic acid, especially adipic acid, and / or an acid anhydride, especially phthalic anhydride, with glycol or a mixture of glycols and esterification of end groups with a monocarboxylic acid or a monohydric alcohol, with the separation and removal of condensation water, characterized by in that adipic acid, phthalic anhydride or their mixture is polycondensed with a glycol of the general formula HO-CH2CR1R2-CH2-OH in which R1 and R2 are different and - if R1 is a methyl group, R2 is a hydrogen atom or an ethyl group , and if R1 is ethyl, then R2 is n-butyl, or R1 and R2 together represent a ring group (CH2) 5 and together with the central carbon atom in the general formula HO-CH2-CR1R2-CH2-OH form a cyclohexane ring, or is subjected to polycondensation with a glycol mixture of the general formula HO-CH2CR1R2-CH2-OH, wherein R1 and R2 are as defined above, with glycol ethylene, diethylene, neopentyl, 1,4-butylene, 1,2-propylene or 1,3-propylene oles, the content of glycol of the general formula HO-CH2CR1R2-CH2-OH in the glycol mixture is at least 5 mole%, and the end groups of the product obtained are preferably esterified with 2-ethylhexanol. 2. The method according to p. A process as claimed in claim 1, characterized in that 2-methyl-1,3-propanediol or 2-ethyl-2-methyl-1,3-propanediol is used as the glycol or component of the glycol mixture, especially in a mixture with ethylene or 1,2-propylene glycol. . 3. The method according to p. A process as claimed in claim 1, characterized in that 2-butyl-2-ethyl-1,3-propanediol is used as the glycol or component of the glycol mixture, especially in a mixture with ethylene or diethylene glycol. 4. The method according to p. A process as claimed in claim 1, characterized in that 1,1-bis (hydroxymethyl) cyclohexane is used as the glycol or component of the glycol mixture, in particular in a mixture with neopentyl or 1,4-butylene glycol. 5. The method according to p. The process according to any of the claims 1-4, characterized in that the mixture of adipic acid and phthalic anhydride is used in which the molar ratio of adipic acid and phthalic anhydride is from 1:10 to 10: 1.