WO2015050685A1

WO2015050685A1 - Benzoate blend

Info

Publication number: WO2015050685A1
Application number: PCT/US2014/055361
Authority: WO
Inventors: George F. Schaefer; Ronald J. RALEIGH, Jr.; Brenda Hollo; John D. Bradshaw; Larry J. Baldwin
Original assignee: Ferro Corporation
Priority date: 2013-10-03
Filing date: 2014-09-12
Publication date: 2015-04-09

Abstract

A liquid ester composition includes aryl polyol esters: (a) a first diester of the formula ArC(O)(OCH₂CH₂)₂O(0)CAr, (b) a triester of the formula ArC(O)(OCH₂CH(OC(O) ArCH₂O(O)CAr, and (c) a second diester of the formula ArC(O)(OCH(R)CH(R)O)n(0)CAr, wherein (d) Ar represents a phenyl radical, and R represents -CH₃ or H wherein only 1 of the groups R is a H atom in the triester, and n is 1 to 3, wherein, the weight ratio of the first diester to the triester is 1:1 to 20:1 and wherein the weight ratio of the first diester to the second diester is 1:1 to 3.5:1.

Description

Benzoate Blend

BACKGROUND OF THE INVENTION

1. Field of Invention

[0001] The invention relates to plasticizers having a lower freezing point than known plasticizers. The plasticizer mixture of the invention is highly compatible with thermoplastic resins such as PVC, polyacrylates and polyurethane resulting in an easy-to-process mixture allowing for production of a variety of products with a reduced carbon footprint.

2. Description of Related Art

[0002] Plasticizers are compounds or mixtures of compounds that are added to polymer resins to impart softness and flexibility. Most commercial plasticizers are sourced from fossil-based materials such as crude oil.

[0003] Esters derived from benzoic acid and aliphatic glycol or an oligomer thereof together with methods of preparing such esters are known in the art.

[0004] Certain of these esters, particularly, esters derived from glycols containing from 2 to 9 carbon atoms, constitute a preferred class of plasticizers for polyvinyl chloride and other thermoplastic polymers because of the esters' ability to improve the processability of rigid polymers without adversely affecting their desirable physical properties.

[0005] U.S. 4,656,214 teaches diesters of (1) linear glycols containing 2-8 carbon atoms, (2) a first carboxylic acid of formula R¹ R² R³ C(0)OH and (3) a second carboxylic acid of the formula R⁴ C(0)OH, wherein R¹ and R² are individually selected from alkyl groups having 1 -4 carbon atoms, and R³ is hydrogen or a Ci -C₆ alkyl group. R⁴ is selected from phenyl, mono- di and trialkyl-substituted phenyl containing 9 to 12 carbon atoms, and -(CH₂)_nPh where Ph isphenyl and n is 1 to 6. The esters contain 16-19 carbon atoms.

[0006] JP 54/18859 describes esters derived from benzoic acids used as plasticizers.

[0007] European Patent Application No. 244,107 describes plasticizer compositions for elastomers comprising (1) trimellitate ester, (2) saturated linear dicarboxylate ester obtained by reacting (a) a dicarboxylic acid with at least one monohydric alcohol or (b) an aliphatic monocarboxylic acid with diethylene glycol and (3) a dialkyl ester of thiodicarboxylic acid. [0008] U.S. 4,444,933 describes cyanoacrylate adhesives containing a plasticizer selected from the group consisting of dipropylene glycol dibenzoate, diethyl ene glycol dibenzoate, a mixture of the foregoing, butylbenzyl phthalate, dibutyl phthalate, or a benzoate ester of a di- or

polyhydroxy branched aliphatic compounds.

[0009] U.S. 5,990,214 and 6,184,278 describe di-and Methylene glycol esters of benzoic acid and toluic acids blended in a limited range of proportions having a freezing point below that of the individual esters and useful as plasticizers.

[0010] Research disclosure No. 17943, (cited in U.S. 6,184,278), published March 1979 describes road marking compositions containing 10-50 wt% of a benzoic acid plasticizer exemplified by glyceryl tribenzoate, neopentyl dibenzoate, triethylene glycol dibenzoate and trimethylol ethane tribenzoate or a polyester.

[0011] Diethylene glycol dibenzoate has a relatively high freezing point, 25 °C, which reduces market value because of processability problems. Glyceryl tribenzoate has an even higher freezing point, 68 °C.

[0012] It would be useful in the plastics and plasticizers industries to provide biobased plasticizers to thereby reduce the carbon footprint of industrial processes.

SUMMARY

[0013] Plasticizers based on carbon from flora or fauna sources provide improved sustainability and also reduce the amount of carbon dioxide being added to the atmosphere.

[0014] The inventors have discovered that combining glyceryl tribenzoate, 2,2,4- triemthylpentane-l,3-disobutanoate or 2,2,4-trimethylpentane-l-benzoate-3-isobutanoate or 2,2,4-trimethylpentane- 1,3 -dibenzoate or mixtures of the above with diethylene glycol dibenzoate and dipropylene glycol dibenzoate in a relatively limited range of proportions unexpectedly results in not only a lower freezing point than either the glyceryl tribenzoate and the diethylene glycol dibenzoate, but also a mixture that is highly compatible with the thermoplastic resins such as polyvinyl chloride, polyacrylates, polyvinyl acetate and

polyurethane, resulting in an easily processed mixture that allows for production of a variety of products with a reduced carbon footprint because glycerol can be derived from flora or fauna oils. Products include materials that are formed by calendaring for example films or materials formed by extrusion for example toys or materials in the form of a latex or plastisol for example sealants, caulks and adhesives.

[0015] The invention involves a liquid ester composition comprising aryl polyol esters as follows:

(a) a first diester of the formula ArC(0)(OCH₂CH₂)₂0(0)CAr,

(b) a triester of the formula ArC(0)(OCH₂CH(OC(0)ArCH₂0(0)CAr, and

(c) a second diester of the formula ArC(0)(OCH(R)CH(R)0)_n(0)CAr, wherein

(d) Ar represents a phenyl radical, and R represents -CH₃ or H wherein only 1 of the groups R is a H atom the triester, and n is 1 to 3 and wherein,

(e) the weight ratio of the first diester to the triester is 1 :1 to 20: 1 and wherein

(f) the weight ratio of the first diester to the second diester is 1 : 1 to 3.5 : 1.

[0016] In a preferred embodiment, the weight ratio of the first diester to the triester is 3 : 1 to 20: 1, more preferably 5: 1 to 20:1 , still more preferably 5:1 to 15:1.

[0017] In a preferred embodiment, the weight ratio of the first diester to the second diester is 2: 1 to 3.5:1, more preferably 2.5:1 to 3.5: 1.

[0018] In a preferred embodiment, the first, second and third esters constitute at least 50 wt% of the liquid ester composition. The third ester is the triester.

[0019] The liquid ester compositions herein are useful as plasticizers.

[0020] The invention provides a liquid ester composition comprising diol esters as follows:

(a) a first diester of the formula ArC(0)(OCH₂CH₂)₂0(0)CAr,

(b) a second diester of the formula R'C(0)(OCH₂C(C)(C)CH₂CHO(CH)(CH3)₂(0)CR'

(c) a third diester of the formula ArC(0)(OCH(R)CH(R)0)_n(0)CAr, wherein

Ar represents a phenyl radical, R represents -CH₃ or H, and R' represents either a phenyl radical or CH(CH₃)₂ and n = 2, wherein

the weight ratio of the first diester to the second diester is 1 :1 to 20:1 and wherein, and the weight ratio of the first diester to the third diester is 1 :1 to 3.5:1.

[0021] In a preferred embodiment, the weight ratio of the first diester to the second diester is 3 : 1 to 20: 1, more preferably 5:1 to 20:1, still more preferably 5: 1 to 15:1. In a more preferred embodiment, the weight ratio of the first diester to the third diester is 2: 1 to 3.5:1, more preferably 2.5: 1 to 3.5:1. In a preferred embodiment, the first, second and third esters constitute at least 50 wt% of the liquid ester composition. [0022] Another embodiment of the invention is a method of reducing the melting point of a plasticizer, comprising adding to a conventional plasticizer a biobased plasticizer made by a method comprising:

(a) providing a first, biobased, diester of the formula ArC(0)(OCH₂CH₂)₂0(0)CAr,

(b) providing a biobased triester of the formula ArC(0)(OCH₂CH(OC(0)ArCH₂0(0)CAr, and

(c) providing a second biobased diester of the formula ArC(0)(OCH(R)CH(R)0)n(0)CAr,

(d) blending the biobased triester with the first and second biobased diesters,

wherein Ar represents a phenyl radical, and R represents -CH₃ or H wherein only 1 of the groups R is a H atom in the triester, and n is 1 to 3 and wherein, the weight ratio of the first diester to the triester is 1 :1 to 20:1 and wherein the weight ratio of the first diester to the second diester is 1 :1 to 3.5: 1.

[0023] In the method, the weight ratio of the first diester to the triester may be 3:1 to 20:1, preferably 2:1 to 3.5: 1. Other ratios of esters disclosed elsewhere herein are suitable for this method. In a preferred embodiment of this method, the first diester is diethyl ene glycol dibenzoate, the second diester is dipropylene glycol dibenzoate, and the triester is glyceryl tribenzoate.

[0024] The liquid ester compositions disclosed herein are useful as plasticizers.

[0025] The reduction in melting point of the plasticizers of the invention leads to improved processability ultimately requiring less energy. The melt points achievable by the inventive liquid ester compositions can be 25 °C or lower, 20 °C or lower, 15 °C or lower, 10 °C or lower, 5 °C or lower, 0 °C or lower, -5 °C or lower, -10 °C or lower, or -15 °C or lower. The preceding sentence is intended to also define melt points between the aforementioned values, which are also achievable.

[0026] Glycerol derived from vegetable oils such as corn and soybean oil or derived from tallow can be esterified by heating glycerol and aryl carboxylic acids in the presence of a catalyst to form triesters of glycerin. Such acids can (but need not) be substituted, with one or more aromatic hydrogens being replaced by alkyl, or ether substituent groups. Suitable aryl acids include, for example, benzoic acid, 2-methylbenzoic acid, 3-methylbenzoic acid, 4- methylbenzoic acid, 2-ethylbenzoic acid, 3-ethylbenzoic acid, 4-ethylbenzoic acid, 4- isopropylbenzoic acid, 4-tertiary butylbenzoic acid, 4-(l-methylpropyl)benzoic acid, 2- ethoxybenzoic acid, 3,4-dimethoxybenzoic acid, 4-methoxy-2-methylbenzoic acid, 4- acetylbenzoic acid. In order to fully esterify one mole of glycerol, three moles of acids are needed. In the preferred embodiment of the invention, for every mole of glycerol that is esterified, a three mole mixture of different acids is used. It will be appreciated that in excess of three moles of aryl acids can be charged to the reactor for every mole of glycerin to be esterified, but only three moles of acids per mole of glycerol will actually react. Excess acids in mole ratios (acid(s) to glycerol) of 3.01, 3.05, 3.1, 3.15, 3.2 and other values in between are suitable. A particularly preferable aryl acid is benzoic acid with 3.03 moles of benzoic acid per mole of glycerol esterified.

[0027] Tri-esters of glycerol according to the present invention are preferably formed by heating glycerin and aryl acids under a partial vacuum in the presence of a catalyst to form the triesters. Suitable catalysts include, for example, acid catalysts such as benzene sulfonic acid and toluene sulfonic acid, metal oxide catalysts such as zinc oxide and titanium oxide, tin (II) 2- ethylhexanoate, dibutyl tin oxide, and zirconium-based catalysts such as zirconium acetate and zirconium oxide. A small excess amount of acid provides reflux for continuous water removal. At the end of the reaction, excess acids can be vacuum stripped from the resulting crude mixture of glycerin triesters, and the crude mixture of glycerin triesters can be further refined to remove color producing species, excess acid, and catalyst.

[0028] Biobased aryl acids can be manufactured by:

1) Processing lignocellusose to synthesis gas.

2) Using the synthesis gas to make biobased methanol.

3) Using the biobased methanol according to U.S. 4,511 ,749 to form toluene.

4) Using the biobased toluene and biobased methanol to produce xylenes according to U.S 7,049,260.

5) Using biobased toluene and alkylating to form alkylated toluene.

6) Oxidizing toluene or xylenes or alkylated toluenes to benzoic acid or alkylated benzoic acid.

[0029] An embodiment of the invention is a method of making a liquid ester composition comprising:

(a) providing a first, biobased, diester of the formula ArC(0)(OCH₂CH₂)₂0(0)CAr, (b) providing a biobased triester of the formula ArC(0)(OCH₂CH(OC(0)ArCH₂0(0)CAr, and

(c) providing a second, biobased diester of the formula ArC(0)(OCH(R)CH(R)0)n(0)CAr,

(d) blending the first and second diesters and triester, wherein

(e) Ar represents a phenyl radical, and R represents -CH₃ or H wherein only 1 of the groups R is a H atom in the triester, and n is 1 to 3 and wherein, the weight ratio of the first diester to the triester is 1 :1 to 20: 1 and wherein the weight ratio of the first diester to the second diester is 1 : 1 to 3.5:1.

[0030] The foregoing and other features of the invention are hereinafter more fully described and particularly pointed out in the claims, the following description setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principles of the invention may be employed.

DETAILED DESCRIPTION OF THE INVENTION

[0031] The compounds of the invention are used to soften thermoplastic polymer resins that would otherwise be brittle and inappropriate for many applications. Plasticizers improve flexibility and tensile strength in such resins.

[0032] It will be appreciated that the liquid ester compositions of the invention are useful as plasticizers for a variety of thermoplastic polymer resins, elastomers, and thermoplastic elastomer compositions. Examples of the foregoing include polyolefms, styrenic polymers, polyamides, polyesters, polyacrylics, polyurethanes, polycarbonates, and copolymers and polymer blends and alloys of the foregoing. Among these, PVC resins, polypropylene and polyethylene are noted.

[0033] The invention provides a liquid ester composition comprising aryl polyol esters as follows:

(a) a first diester of the formula ArC(0)(OCH₂CH₂)₂0(0)CAr,

(b) a triester of the formula ArC(0)(OCH₂CH(OC(0)ArCH₂0(0)CAr, and

(c) a second diester of the formula ArC(0)(OCH(R)CH(R)0)_n(0)CAr, wherein

(e) the weight ratio of the first diester to the triester is 1 : 1 to 20: 1 and wherein

[0034] In a preferred embodiment, the weight ratio of the first diester to the triester is 3: 1 to 20: 1, more preferably 5:1 to 20: 1 , still more preferably 5: 1 to 15:1.

[0035] In a preferred embodiment, the weight ratio of the first diester to the second diester is 2 :1 to 3.5: 1, more preferably 2.5:1 to 3.5: 1.

[0036] An embodiment of the invention is a method of making a liquid ester composition comprising:

(c) providing a second, biobased diester of the formula ArC(0)(OCH(R)CH(R)0)n(0)C Ar,

(d) blending the first and second diesters and triester, wherein Ar represents a phenyl radical, and R represents -CH₃ or H wherein only 1 of the groups R is a H atom in the triester, and n is 1 to 3 and wherein, the weight ratio of the first diester to the triester is 1 :1 to 20:1 and wherein the weight ratio ofthe first diester to the second diester is 1 :1 to 3.5: 1.

[0037] Examples of liquid esters that can be present in the inventive ester compositions include (a) diesters derived from benzoic acid and diols containing from 3 to 10 carbon atoms; (b) diesters derived from benzoic acid and monohydric alcohols containing from 8 to 15 carbon atoms (c) aliphatic esters of the formula R¹0(0)C(CH₂)iiC(0)0 R¹; (d) esters derived from phthalic acid and alcohols containing from 4 to 12 carbon atoms, (e) esters derived from cyclohexane 1,2- dicarboxylic acid and alcohols containing from 1 to 13 carbon atoms. In the preceding formula, R¹ represents alkyl groups independently selected from the group consisting of alkyl radicals and aryl radicals having 4 to 12 carbon atoms and n is an integer from 2 to 10.

[0038] In a preferred embodiment, the first, second and third esters (the third ester being the triester) constitute at least 50 wt% of the liquid ester composition. The remaining ingredients of such preferred embodiment are esters having freezing points below 25 °C, including, for example: 1,2-propanediol dibenzoate; 1,3 -propanediol dibenzoate; 1,2-butanediol dibenzoate;

1.3- butanediol dibenzoate; 1 ,4-butanediol dibenzoate; 2,2-dimethyl-l,3-propanediol dibenzoate;

1.4- butanediol dibenzoate; 2,2,3-trimethyl-l,3-pentanediol dibenzoate; tri ethyl citrate; acetyl tri ethyl citrate; Acetyl tributyl citrate; 1,10-decanediol dibenzoate; benzyl butyl 1,2- cyclohexanedicarboxylate; di-isononyl 1 ,2-cyclohexanedicarboxylate; di-2-ethylhexyl terephthalate; isosorbide dibenzoate; methyl esters of epoxidized fatty acids from vegetable oils; di-2-ethylhexyl adipate; n-octyl benzoate; 2-ethylhexyl benzoate, isooctyl benzoate; nonyl benzoate; isononyl benzoate; decyl benzoate; isodecyl benzoate; undecyl benzoate; dodecyl benzoate; tridecyl benzoate; tetradecyl benzoate; pentadecyl benzoate.

[0039] These additional esters are derived from mono- or polyhydric alcohols and aromatic or aliphatic mono- and/or dicarboxylic acids.

[0040] The combined weight of these additional plasticizers can constitute up to 50 and preferably from 10 to 35 wt% of the inventive compositions. The diols used herein can contain heteroatoms such as oxygen in the hydrocarbon chain.

[0041] An embodiment of the invention is a plastic mass or plastic article including any plasticizer made by any method disclosed herein or including any liquid ester composition herein. [0042] An embodiment of the invention is a plastic mass or plastic article including a liquid ester composition made by any method disclosed herein.

[0043] An embodiment of the invention is a method of plasticizing a plastic mass comprising combining any liquid ester composition disclosed herein with a plastic mass.

[0044] Examples:

[0045] Examples 1 through 6 are given in Table 1. Table 1 data was generated from results of DSC determination of the freezing point for the materials and mixtures listed. The DSC conditions were: Sample Cell purged with N2 at 25 mL/minute and sample was encapsulated in a hermetic pan and dipped in liquid nitrogen. The pan was immediately placed in the cell at a temperature of -60°C. The oven was ramped from -60°C to 50°C at 5°C/minute.

TABLE 1

Freezing Point

(weight % in composition) _

diethylene glycol dibenzoate (100) 25

dipropylene glycol dibenzoate (100) -6

glyceryl tribenzoate (100) 68

diethylene glycol dibenzoate (75) triethylene glycol

-18

dibenzoate 25

diethylene glycol dibenzoate (70) + dipropylene

-16

glyco[ dibenzoate (20) + glyceryl tribenzoate (10)

diethylene glycol dibenzoate (70) + dipropylene

glycol dibenzoate (20) + 2,2,4-trimethylpentane-l,3- dibenzoate (2.5) + 2,2,4-trimethylpentane-l- -17

benzoate-3-isobuterate (6.7), + 2,2,4- trimethylpentane 1,3 dibuterate (0.8)

Claims

1. A liquid ester composition comprising:

a. a first diester of the formula ArC(0)(OCH₂CH₂)₂0(0)CAr,

b. a triester of the formula ArC(0)(OCH₂CH(OC(0)ArCH₂0(0)CAr, and c. a second diester of the formula ArC(0)(OCH(R)CH(R)0)n(0)CAr, wherein d. Ar represents a phenyl radical, and R represents -CH₃ or H wherein only 1 of the groups R is a H atom in the triester, and n is 1 to 3 and wherein,

e. the weight ratio of the first diester to the triester is 1 :1 to 20: 1 and wherein f. the weight ratio of the first diester to the second diester is 1 : 1 to 3.5 : 1.

2. The liquid ester composition of claim 1 , wherein the weight ratio of the first diester to the triester is 3:1 to 20: 1

3. The liquid ester composition of claim 1, wherein the weight ratio of the first diester to the triester is 5:1 to 20:1.

4. The liquid ester composition of claim 1, wherein the weight ratio of the first diester to the triester is 5:1 to 15:1.

5. The liquid ester composition of claim 1, wherein the weight ratio of the first diester to the second diester is 2: 1 to 3.5:1.

6. The liquid ester composition of claim 1, wherein the weight ratio of the first diester to the second diester is 2.5:1 to 3.5:1.

7. A plastic mass or plastic article including the liquid ester composition of claim 1.

8. A plastic mass or plastic article including the liquid ester composition of claim 2.

9. A plastic mass or plastic article including the liquid ester composition of claim 3.

10. A plastic mass or plastic article including the liquid ester composition of claim 4.

11. The liquid ester composition of claim 1, wherein the triester is selected from the group consisting of glyceryl tribenzoate, 2,2,4-triemthylpentane-l,3-disobutnoate or 2,2,4- trimethylpentane-l-benzoate-3-isobutanoate or 2,2,4-trimethylpentane-l,3-dibenzoate or mixtures of any of the foregoing with at least one of diethylene glycol dibenzoate and dipropylene glycol dibenzoate.

12. The liquid ester composition of claim 1, wherein the first diester is diethylene glycol

dibenzoate, and the second diester is dipropylene glycol dibenzoate.

13. The liquid ester composition of claim 1, wherein the triester is selected from the group

consisting of glyceryl tribenzoate, 2,2,4-triemthylpentane-l,3-disobutanoate, 2,2,4- trimethylpentane- 1 -benzoate-3 -isobutanoate, 2,2,4-trimethylpentane- 1 ,3 -dibenzoate, and combinations thereof.

14. The liquid ester composition of claim 12, wherein the triester is selected from the group consisting of glyceryl tribenzoate, 2,2,4-triemthylpentane-l,3-disobutanoate, 2,2,4- trimethylpentane- 1 -benzoate-3 -isobutanoate, 2,2,4-trimethylpentane- 1 ,3 -dibenzoate, and combinations thereof.

15. The liquid ester composition of claim 1, wherein the triester is glyceryl tribenzoate.

16. The liquid ester composition of claim 1, wherein the triester is 2,2,4-triemthylpentane-l,3- disobutanoate.

17. The liquid ester composition of claim 1, wherein the triester is 2,2,4-trimethylpentane- 1- benzoate-3 -isobutanoate.

18. The liquid ester composition of claim 1, wherein the triester is 2,2,4-trimefhylpentane-l,3- dibenzoate.

19. A method of reducing the melting point of a plasticizer, comprising adding to a conventional plasticizer a biobased plasticizer made by a method comprising:

a. providing a first, biobased, diester of the formula ArC(0)(OCH₂CH₂)₂0(0)CAr, b. providing a biobased triester of the formula

ArC(0)(OCH₂CH(OC(0)ArCH₂0(0)CAr, and

c. providing a second, biobased diester of the formula

ArC(0)(OCH(R)CH(R)0)n(0)CAr,

d. blending the biobased triester with the first and second biobased diesters, wherein Ar represents a phenyl radical, and R represents -CH₃ or H; wherein,

only 1 of the groups R is a H atom in the triester, and n is 1 to 3; wherein, the weight ratio of the first diester to the triester is 1 :1 to 20:1; and wherein, the weight ratio of the first diester to the second diester is 1 : 1 to 3.5 : 1.

20. The method of claim 19, wherein at least one of the diesters and triester is formed by

esterifying biobased glycerol.

21. The method of claim 20, wherein esterifying biobased glycerol includes providing a biobased compound selected from the group consisting of biobased glycerol, biobased 2,2,4- triemthylpentane-1 ,3-disobutnoate, biobased 2,2,4-trimethylpentane-l -benzoate-3- isobutanoate biobased 2,2,4-trimethylpentane-l, 3 -dibenzoate or mixtures of the foregoing with at least one biobased aryl acid in a ratio of at least 3 moles aryl acid per mole of biobased compound.

22. The method of claim 21, wherein the at least one biobased aryl acid is selected from the group consisting of benzoic acid, 2-methylbenzoic acid, 3-methylbenzoic acid, 4- methylbenzoic acid, 2-ethylbenzoic acid, 3-ethylbenzoic acid, 4-ethylbenzoic acid, 4- isopropylbenzoic acid, 4-tertiary butylbenzoic acid, 4-(l-methylpropyl)benzoic acid, 2- ethoxybenzoic acid, 3,4-dimethoxybenzoic acid, 4-methoxy-2-methylbenzoic acid, 4- acetylbenzoic acid.

23. The method of claim 20, wherein esterifying biobased glycerol includes providing a catalyst.

24. The method of claim 23, wherein the catalyst is selected from the group consisting of

benzene sulfonic acid, toluene sulfonic acid, metal oxide catalysts, zinc oxide, titanium oxide, tin (II) 2-ethylhexanoate, dibutyl tin oxide, zirconium-based catalysts, zirconium acetate and zirconium oxide.

25. The method of claim 19, wherein the first diester is di ethylene glycol dibenzoate, the second diester is dipropylene glycol dibenzoate, and the triester is glyceryl tribenzoate.

26. A plastic mass or plastic article including the liquid ester composition made by the method of claim 19.

27. A method of plasticizing a plastic mass comprising combining the liquid ester composition of any of claims 1-6 with a plastic mass.

28. A method of making a liquid ester composition comprising:

a. providing a first, biobased diester of the formula ArC(0)(OCH₂CH₂)₂0(0)CAr, b. providing a biobased triester of the formula

ArC(0)(OCH₂CH(OC(0)ArCH₂0(0)CAr, and

c. providing a second, biobased diester of the formula

ArC(0)(OCH(R)CH(R)0)n(0)CAr,

d. blending the first and second , di esters and triester, wherein

Ar represents a phenyl radical, and R represents -CH₃ or H wherein only 1 of the groups R is a H atom in the triester, and n is 1 to 3 and wherein, the weight ratio of the first diester to the triester is 1 :1 to 20:1 and wherein the weight ratio of the first diester to the second diester is 1 :1 to 3.5:1.