CA1051593A - Alkanedioicacid-branched glycol-monoaromatic acid polyester plasticizers and polyvinylchloride compositions containing the same - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

Improved chain-stopped polyester plasticizers for polyvinyl chloride homopolymers and copolymers are provided.
The chain-terminated polyester has an average molecular weight between 1500 and 10000, and is obtained from the esterification of (a) an alpha-omega alkanedioic acid containing from 4 to 12 carbon atoms and (b) a branched chain dihydric alcohol containing from 4 to 10 carbon atoms and having only primary and secondary hydroxyl groups with (c) 3 to 15 mol percent, based on the total organic acids, of an aromatic monocarboxylic acid containing from 7 to 20 carbon atoms. The plasticizers show little or no tendency to migrate from PVC, yet they are readily processable with the PVC. While being extremely compatible with PVC the present plasticizers bave very low affinity for ABS and poly-styrene resins and therefore can be used in applications where plasticized PVC comes in contact with these other resins.

Description

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This inv~ntion relates to polyester compositions.

In order for a compound to function as a plasticizer for polyvinyl chloride (PVC1 it must have sufficient affinity for the PVC to resist migra~ion from ~he internal regions to tne surface, ho-~ever, some de~ree of mob~llty must be maintained ~itnin the polymer s.ructure if flexi~ility is to be achieved.
~ proper balance ~et~een these two conflictlng considerations must be maintained for effective and useful plasticization of PVC. Tne pro~lem of the selection of a suitable plasticizer for PVc ~s further complicated when the plasticized PVC ~ill come in contact with another dissimilar polymeric material.
In these situations the p~sticizer should not have affinity for the second polymer, other~ise the plasticizer will migrate to the surface of the PVC and into tlle other polymer substrate.
In addition to reducing the amount of plasticizer in the PVC
and thus detracting from the physical properties this uncontrol~
migration can be even more detrimental to the other polymeric material. Migr~tion of plasticizer to certain elastomeric , polymers can for example, cause s~elling of the ela~tomer. In the case of plasticizer migration to~ri~id materials stress cracki,ng and embrittlement comm~nly occur.
. . , . -: ' Plasticizer migration is particularly troublesome in situations ~llere plasticized PVC is contacted with polystyrene ~ ~ ' and acrylonitrile-butadienestyrene (ABS) resins. With ABS, marring of the ABS surface at the interface is common when`
conventional easy-processing type PVC plasticizers are used.
The surface of the ~BS becomes dull and is often acco~panied by noticeable softening ands~.JelIing. In addition to a~fec~ing the appearance adversely, the polymer may be affected internally as evidenced by deterioration of the physical properties. `
Stress crackina (the formation of numerous tiny internal and surface cracks aligned in the s,a,me d;`rection and usually ' arrang~d in more or less parallel plains) is the result of plasticizer migration ana is attended by a loss in the physical strength of the polymer. Polystyrene resins are particularly . ~' ' .
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prone to stress cracking (crazing) i~ the~ are placed in~
contact with PVC coml)ositions plasticized with known easy~
processing plasticizer types. I
In view of the above-mentioned difficulties it would be highly desirable and advantageous to develope plasticizers for PVC which are readily processable and compatible with PVC
but are essentially non-migrating. It would be even more desirable it these plasticizers had little or no aEfinity for ABS or polystyrene resins.
Lo Non-migrating polyester plasticizers have now been discovered which preferably have 210F viscosities of 200-250 `~
centistokes and which are readily processable with PVC homopoly~
mers and copolymers. These polyesters have the further advantage ; ~;
that they have little or no affinity for ABS and polystyrene resins and therefore when plasticized PVC comes ln contact with these resins, marring and crazing of the ABS and polystyrene is virtually elimintated. The presen-t improved plasticizer compositions of one aspect of this invention are chain-stopped polymers having average molecular weights from 1500 to 10000,-and more preferably from 2000 to 5000, the composition being obtained from the esterification of (a) an alpha-omega alkanedioic acid containing fronl 4 to 12 carbon atoms and tb) a branchèd chain dihydric ; alcphol containing from 4 to 10 carbon atoms and having only primary and secondary hydroxyl groups with tc) 3 to 15 mol percent, based on the total organic acids, of an aromatic mono-carboxylic acid con-taining from 7 to 20 carbon atoms.
By one variant thereof, ta) is an aliphatic dicarboxylic ~ ?~
acid containing 6 to 10 carbon-atoms and wherein (b) is selected from the group consisting of 2-hydroxymethyl-2-methylpropyl-2-hydroxymethyl 2-methyl-propionate, neopentyl glycol, 2-methyl-1, .. . .... . . .. .
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. ~' :, :L[)5~593 3-propane diol, 3-methyl-1,5-pentane diol, 2,2,4 trimethyl-1,3-pentane diol,

2,3-dimethyl, 2,3-butane diol, 1,2-propylene glycol, 1,3-butylene glycol, 1,2-butanediol, 1,2-pentanediol~ 1,3-pentane-diol, 1,4-pentanediol.
By another variant, ta) comprises an aliphatic saturated dicarboxy-lic acid containing 6 to 10 carbon atoms; and wherein (b) comprises 2-hy-drox~nethyl-2-methylpropyl-2-hydroxy~ethyl-2-methylp~opionate having the structural formula:

HOCH2--I--CH2--0~--Cl CH20H
C~13 CH2 By a variation thereof, the polyester composition has an average molecular weight in the range 2000 to 5000 and a viscosity at 210F of 200 to 250 centistokes.
By yet another variant, (a) is adipic acid, azelaic acid or sebacic acid and (c) is benzoic acid or a Cl_4 alkyl substituted benzoic acid.
By a further variant, ~c~ constitutes 6 to 12 mol percent of the total organic acids. _ By another aspect, an improved polymer composition is provided comprising polyvinyl chloride homopolylner or polyvinyl chloride copolymer and 10 to 150 parts by weight per 100 parts vinyl resin of a chain-termina-ted polyester having an average molecular weight between 1500 and 10000, said composition being obtained from the esterification of (a) an alpha-omega alkanedioic acid containing from 4 to 12 carbon atoms and (b) a branched chain dihydric alcohol containing from 4 to 10 carbon atoms and having only primaly and secondary hydroxyl groups with ~c) 3 to 15 mol percent, based on the total organic acids, of an aromatic monocarboxylic acid containing fTom 7 to 20 carbon atoms.
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:105~5~3 By one variant, the polyester has an average molecular weight in the range 2000 to 5000 and a viscosity at 210F of 200 to 500 centi-stokes and is obtained fTom the esterification of (a) adipic acid, azelaic acid or sebacic acld and (b) a dihydric alcohol selected from the group ~;
consisting of 2-hydroxynethyl-2-methylpropyl-2-hydroxymethyl-2-methyl-propionate, neopentyl glycol, 2-methyl-1,3-propane diol, 3-methyl 1,5- .
pentane diol, 2,2,4-trimethyl-1,3-pentane diol, 2,3-dimethyl, 2,3-butane diol, 1,2-propylene glycol, 1,3-butylene glycol, 1,2-butanediol, 1,2-pen-tanediol, 1,3-pentanediol, 1,4-pentanediol with (c) 6 to 12 perc`ent based `~
on the total organic acids of benzoic acid or Cl 4 alkyl substituted benzoic acid. ~ `
By another variant, the polyester has an average molecular weight in the range 2000 to 5000 and a viscosity at 210F of 200 to 250-centistokes and is obtained from the esterification of (a) adipic acid, azelaic acid or sebacic acid and ~b) 2-hydroxymethyl-2-methylpropyl-2-hydroxymethyl-2-methylpropionate having the structural formula:
.

By still another variant, the polyester composition contains

3.0 to 110 parts polyester per 100 parts resin.

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-3b-~ ' ~ Molecular weights within these ranges are obtained by the use of an appropriate amount of the chain-stopping agent which is a monobasic aromatic acid containing 7 to 20 ~ :
carbon atoms. Benzoic acid and lower alkyl-substitute benzoic acids are especially useful aromatic acids for this purpose.
Glycols ;
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employed are branched chain C4-C10 diols having either pri-mary or secondary hydroxyl gxoups. Ester-diol (2-1~ydroxy- ~, methyl-2-methylpropyl-2-hydroxymethyl-2-methylpropionate) . .
and'neopentyl glycol are very useful branched chain glycols 5 for the preparation of the present plasticizers. The useful .
dibasic acids are alpha-omega alkanedioic acids containing from 4 to 12, and more preferably from 6 to lO, carbon atoms.
The polyesters of aspects of the present invention are ob- ~
tained using conventional esterification procedures. `' The plasticizer compositions of aspects of the present invention are useful for PVC homopolymers and PVC copol'ymers wherein one or more other ethylenically unsaturated monomers is copolymerize.'d with vinyl chloride. Comonomers useful in ~ ~;
tlhe preparation of the polyvinyl chloridè copolymers include:
vinyl bromide; vinyl- acet`ate; vinylidene chloride; lower allyl ' esters; vinyl alkyl ethers, acrylonitrile and methacrylonitrile;
acrylic acid and methacrylic acid; ac~ylic and methacrylic esters such as methyl acryla~e, ethyl acrylate and methyl ' methacrylate; styrene; and the like. Copolymers obtained by 'the copolymerization of vinyl chloride'with vinyl acetate, vinyl chloride with vinyi butyrate, vinyl chloride with vinyl '' propionate~ vinyl chloride and vinyl methacrylate, vinyl chlor- , ide with vinylidene chloride and vinyl chloride with two or - ~ , , more comonomers such as mlxtures of vlnylidene chloride ànd ' ~' 25 . 2-ethylhexlacrylate find particular utility with the present ; polymeric polymerized vinyl chloride and more preferably 75 wt. X or more bound vinyl chloride. ' ~, , , The improved poly~eric plastici~ers of aspects of this invention are chain-stopped polyesters hsving average mole- ~ , ,-~cular weights ranginSg from 1500 to lO000. Pre~erably the ~ polyesters will r~ange between 2000 and 5000 molecular weight.
-' These polyesters axe obtained by the condensation reaction of , '; ' ' , ` ' ' ' ~4'~ ' ' ' ' " "' ,'' ``~;' ` ,' - ~L05~L5g3 ~
a dibasic acid, a glycol and a quantity of monobasic acid suffi~ient to terminate the chain ends and obtain mol~cular weights in the above defined ranges.
Dibasic acids useful in the formation of the polymeric plasticizers are alpha-omega alkanedioic acid acids contain-ing from 4 to 12 carbon atoms and more preferably from 6 to 10 carbon atoms. Representative aliphatic dicarboxylic acids -of ehe above types include glutaric acid, succinic acid, adipic acid, pimelic acid, suberic-acid, azelaic acid, sebacic acid and dodecanedioic acid. In addition ~o the acids the corre-sponding acid anhydrides may be successfully utilized. Small ~;
amounts of acid impurities, such as, for example, aromatic dicarboxylic acids, may be present without significantly affecting the overall properties of the plasticizers. Adipic acid, azelaic acid and sebacic acid are especially useful for the present invention because of their commer^ial availability and the superior characteristics i.e., ready compatibility wlth the PVC without destroying the processing characteristics ~ ;
of the PVC and little or no eendency to migrate, of plasti-cizers obtained when thesè acids are reacted with ~ranched chain tiols and monobasic aromatic acids which ~ill subse-quently be more fully deccribed.
The glycols used are branched-chain dihydric alcohols -;
containing from about 4 to 10 carbon atoms. The hydroxyl groups ~ay be either primary or secondary, however, glycols containing tertiary groups are not recommended. For the pur-pose of ~hio invention a ~lycol containing a secondary hydroxyl group is considered eo be a branched-chain alcolol. Useful glycols of the above ~ype include: 2-hydroxymethyl-2-methyl-propyl-2-hydroxymethyl-2-methylpropionate (hereinafter re-~erred to as ester-diol), neopentyl glycol, 2-methyl-1,3 propane diol, 3-methyl-1,5-pentane diol, 2,2,4-trimethyl~
- 3-pentane dlol, 2,3-dlmethyl, 2,3-butane dioi-, 1,2-propylene ~-;~ ` `- ~5~
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~051593 glycol, 1,3-butylene glycol, 1,2-butanediol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, and the like. E~cep~ional results are obtained when neopentyl glycol or ester-diol are used as the branched-chain diol, either by themselves or in combination with other diols.
While branched chain glycols are essential if plas-ticizers having the desired low ~igration and compatibility with PVC are to be obtained, it is not necessary ~hat the `
.
total glycol charge consist of branched-chain diols. Up to .
30 wt. % of the total glycol charge can consist of linear diols, however, it is preferred when linear glycols are ?
present that they comprise less than 20% of the total gly-col charge. Other glycols which can be included in the diol . .
charge are linear aliphatic primary glycols containing from 2 to 12 carbon atoms, such as, for example, ethylene glycol, 1,3-propylene glycol, 1,4-butylene glycol and the like.`

- - To achieve plasticizers having the desired balance , -of migration properties and compa~ibility with PVC and which ..
have molecular weights in the above defined ranges it is essential tha~ an aromatic monobasic acid be employed as a chain terminator.~ These aromatic ~onocarboxylic acids will contain from 7 to 20 carbon atoms. They may additionally contain one or more other substituents on the aromatic nucleus ~
such as, for example, alkyl, nitro, halo, alkoxyl and acyl ~ ;
groups. Typical mono~asic aromatic àcids of the above types ; include benzoic acid, the toluic acids, the nitrobenzoic "~ ;

acids, the methoxybenzoic acids, the chlorobenzoic acids and the like. ~ecause of their ready availability and the superior results obtained therewith, the benzoic acid and ~-Cl 4 alkyl substituted benzoic acids are preferred for use . .

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~051.593 as the chain terminator.
Although each Qf the components of the polymeric plast1cizers of aspects of this invention is kno~n in the prior art, the plasticizer compositiGns of aspects of this invention are novel and possess unique properties. This is a result of the particular combination of reactants and ' the proportions at which they are employed. Absence of ~
branched chain glycols or failure to chain terminate with a monobasic aromatic acid will not yield plasticizers hav- ' . . .
ing the desired properties, that is, which are readily com-patible with PVC yet have little or no tendency to migrate from ~he PVC to ABS or polystyrene, thus eliminating craz-' ' ing and marring of the ABS and polystyrene polymers.
.
. . .
' The plasticizers of aspects of this invention may ~-be used with the'above-described vinyl resins both as pri-mary plasticizers and in combination with secondary~plasti-- clzers. It Is preferred that t~ese polyesters be the solè -~
plasticizer in a'pplications where the polymer will come in '. contact with ABS and polystyrene resins if crazing and mar~
0 ring is to be eliminated. Nhere these are not important ~;'' ; ' considerations, however, P~C resin formulations can be pre-' ' 'pared having a wide range of properties by varying the ;'~
propostion and types of plasticizers used in con~uction ' vith the instant polyesters. The proportion of the poly- ~' estèr plastici2er in the resin may ba varied widely and can . .
' . range from 10 to 150 parts, and preferably from 30 to 110 ' parts by weight, per 100 parts by weight of the vinyl chloride ', homopolymer or copolymer. Nhen ~he plasticizers of aspects of this invention are combined with others the total amount of plasticizer should generally fall in the prescribed ranges.

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lCJ S~S~3 In accordance with aspects of the present invention other ~, compounding ingredients can also be emPloYed in conjunction ~ith the plastici~er/polymer mixture. For example, stabili-'`- zers to protect the resin against the deleterious affects of oxidative, thermal and photochemical degradation, fillers, pigments, dyes, lubricants and other proeessing aids can be incorporated in the plasticized PVC composition. As is - evident to those skilled in the art of compounding and formu-- lating PVC ~udicious selection of the compounding ingredients may be required to maintain the desired physical characteris-tics of the PVC.
' The reaction of the'dicarboxylic acid, branched- ;` ' chain glycol and monobasic aromatic acid terminator to ob~
tain the desired polyester plasticizer compositions is'carried' ';
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~ 15 out in conventional equipment using established esterlEication ~' . .
procedures. The reactants are added to a suitable esterifi-cation kettle as a unit charge. The reaction is then typically heated at a temperature from 150C to 250~C at atmospheric - ' ' pressure for a period of timè sufficient to substantially 20- complete the esterification, usuallY about 3 to 8 hours. ;' ,~ . .
The reaction is generally conducted to an acid value;less than 10 and acid values of 5 or below are even more pre- -~' erred. The rate of esterification can be enhànced by the ' use of suitabie esterification catalyst's such as, for ex-; ; .
' 25 ample, phosphoric acid, sulfuric acid, p-toluene sulfonic ';~
acid, ~ethane sulfonic ac'id, stannous oxalate, alkyl tin ` ~' oxides, tetrabutyl titanate, zinc acetate, sodium carbonate ~ ~' and the like. The amount and type of catalyst can be widely varied, however, most often the amount of catalyst will 'range from 0.1 to 1.0~ by weight of the tqtal reactant charge. '' At the completion~of reaction the catalyst may be deactivated or removed by filtering or other conventional means. While 8~

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- ~0~3L593 the reaction may be conducted en~irely at atmospheric pres-sure it is generally more desirable to apply a vacuum (typi-cally 2-50 mm Hg at 200-250 C) to the system during the latter stages of the reaction. This is particularly advan-tageous if low acid values are to be obtained. It alsofacilitates removal of any excess glycol and small amounts ! o~ other volatile materials which may be present.
Inert diluents such as, for example, benzene, toluene, ;
xylene and the like can be employed in carrying out the re-action, however, they are not necessary. In fact, it isgenerally considered desirable to conduct the reaction with-out diluents since the polymeric plastici~er i6 then suit~ble ;
for use as it is obtained from ~he esterification reactor.
While ehe practice of charging the reactants to form 15 the polyesters ~ill vary it is preferred that the ~onobasic `;
aromatic acid, ehe dibasic acid and branched-chain glycol or mixture of glycols be charged to the reactor with a small excess tbased on the stoichiometric to equivalent amount calculated for the acid present) of the glycol component.

The excess glycol serves as the reaction medlum and is dis-tilled off as the esterification reaction is carried to com-pletion. The removed glycol may be recycled to the esteri-fication reactor if desired. Usually 24% by weight excess glycol (above theory) will suffice for thls purpose, however, more can be utilized if desired. To obtain polyesters in the deslred molecular weight range 3 to 15 mol percent of the organic acid charge will be monobasic aromatic acid. ~ `
` , ~ore usually, the monobasic aromatic acid constitutes 6 to 12 ~mole percent oE the total organic acids.
The following examples serve to illustraee the inven-. . , ~ , .
tion more fully. tIn ehe examples all weights -and percentages are on a weight basis unless otherwise lndicated. ~ ~

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EXA '`~P LE I
PREPAR~TION OF A T~PICAL PLASTICIZER .
The esterification was carried out in a 3-necked round bottom flask e~uipped wit~ a suita~l~ stirrer, a thermometer and a medium len~t~ yigreaux distIllation column and a con-denser. The condenser was arranged so that material could be distilled from the reaction at either atmospheric or reduced pressure. The reactant charge was as follows:

Azelaic Acid 0.970 equivalent Ester Diol 0.2il equivalent*
1,2-propylene Glycol 0.729 equivalent*
Benzoic Acid 0.030 equivalent *A small excess o~ the glycols was employed.

The mixture ~as esterified by slowly heating the contents of the flask to 225-235 ~. while removing the water of re-action. The temperature was ~aintained at this level until ;
the rate of reaction slowed mate~ially as evidenced by a markedly reduced rate of water evolution. At this point a smail amount, about one gram~ of tetrabutyl titanate was added to the reactor and the reaction continued ~hile pulling a vacuum on the system. The pressure ~as gradually reduced ~ith the temperature at 225-250 C. at such a rate that a controlled distillation ~removal of water and excess glycol) took place to a ~inal pressure of about 3 mm. at 225 C. The ~
progr~ss of the reaction was follo~ted by determining the acid `
value tAV~ of the reaction mixture and the reaction was terminated ~hen the ~V reached about 0.5. The reaction mixture was then cooled to room temperature, ~iltered using diatomaceous earth ilter aid to remove catalyst residue and other impurities and then stored for subseque~t evaluation as a plasticizer. The ~inal polyester ~roduct. nad an AV of a . 47, a hydroxyl value of 19.1 and a 21~ F. viscosity of 236 centistokes. The average molecular weight of the resulting polyester determined by vapor pressure osmometry ~ras 4100. The clear light-colored poly~ster was used as a plasticizer, ~rithout further modifiFation : ` ' ' ' ' ' ' -' ' , - - . , ' ' . , . , :
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or p cessing. It ~as readily i~corporated into PVC resln using conv~ntional processin~ e~uipment to ~roduce a clear, pliablc s~eet~
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EXP~5PLES II-VI ' . . - `. .~
A variet~ of ot~er polyester plasticizer compositions '~
~ere prepared in accordance ~ith t~e procedure ~scribed in Exa~ple I. In these Examples an excess of glycol based on `
the total e~uivalents of acid present, was employed. Tne ~ ;
, compositions of these materials in equivalents are set forth in Table ~ as well as the acid-value, hydroxyl value and 210 F.
v~scosity. , ' .- . . .' ~ ' ' , ', . ~
EXAMPLE ~II ' ' , , ' FORMULA~IO~ OF PVC RESIN ' ~; , ' The polyesters prepared in the preceding examples ' '~; `
were evaluated as Plasticizers for P~C in accordance ~7ith the ;`
follo~ing recipe: ' ~, , -.: :- ` . ' ~:
, PVC Resin (k~wn by the trade mark o,f~Ge~n 93). . 100 parts ; Calcium carbonate. . . , . . . . . . . . 40 parts Stabil~zer ~triphenyl phosp~ite~ . , . . l part Stabilizer tmixed Ba-Cd soaps) , . . . . 2 parts Epoxidized soya (6.8-7 oxirane content). 4 parts ' Polyester plasticizer. . . . . . . ~ O ~ 86 parts ', ~ ., ' , ': ' :The PVC and other compounding ingredients were blended for ' ~ ', , about ten minutes on a standard t~o-roll'rub~er mill in which the 6 X 12 inch rolls were h~eated to about 17Q C. The sheets as obtained from the mill were then pressed in sheets of uni-form tnickness us;'ng a chrome~,plated ASTM mold at about 177 C
for six minùtes at a pressure o 15Q0 psi. Suitable specimens were then cut from t;~e pressed sheets for each of the various test~ to be conducted. Performance proper'ies of resins` , obtained in this manner and plasticized with the present poly-ester plasticizer aFe set forth below ` ' .` ' ,' , -10` , , , ,, ,, ,, " .,, : - ' ' . .
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Pyc ~I1'l1 PLASTICIZER OF EX~1~LE
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Elon~ation (%~ 40Q 35Q 345 370 100% Modulus (psi~ 70Q 850 75~ 740 Tensile Strenat~ C~si~19QQ 2050 1825 1950 Shore "A" Hardness 68 80 72 75 ~ittle Point L~C~~12.5 - i.5 -9.5 -12.5 -~,' ` . . ' '' ' . `
Extraction C~ ~rt. lossI:
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Hexane C25C;24 hrsl 2.g --- Q.4 1.`0 ` Oil (50 C; 24 hrs) 0.8 0.~ 0.7 0.
~` Soapy Water (90 C;24 hrs) 4.2 S.9 5.8 4.6 ~, . ' ' ' ,' , , . . ~ , The above data shows that excellent physlcal pro~erties ~
~;~ are obtained for PVC plas'ici2ed with the~resent pol~ester ~ ~-com~ositions and that these polyesters have little or no tenclency to migrate and are highly resistant to extraction.
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EXAMPLE VIII . ` - .
~, '. '' ~ .` '`;''.~' , The plasticizer o~ Example I for~ulated in accordance ~it~ Example VII was evaluated for a~ility to resist migration and marring of ABS resins and compare with comparable PVC
formulations ~lasticized with well-known commercially available plasticizers. In this test, referred to as the sand~icn test, a 1 X 1 inch specimen is cut from 75 mil com~ounded PVC sheet -~
and placed on the smooth side of the ~BS test panel. The panel and test specimen are then sand~iched between two 2ieces of glass and a pressure of 2 psi maintained. The assem~ly is th~n placed in a 7Q C. oven for 1~ days. ~t the completion of the test period the PVC is removed ~rom` the ABS panel and the ABS surface visually examined to determine the extent o - marring on the surface of the ABS. Using three differen~
commercially available ABS resins and PVC plasticized with the : -12-, ' . .' . ' ' . , .
',',' ''` . , . . : `'' , ` .' S~593 polyester of Exa~ple 1, no marring was observed for one oE the ABS samples and only sligllt marring was present with the other - two ABS samples. These same ABS resins tested with PVC formu-- ated in the same manner but using commercial plasticizers (known by the Trade Marks of Paraplex G-57 and Santicizer 429) showed significantly increased marring. With both commercial plasticizers seYere marring was obtained with two of the ABS
resins and moderate marring was observed with the other AB$
samples.
.10 EXAMPLE IX ~ ~;
To further demonstrate the resistance of the present ~,`
polyester composition to migration, thus minimizing or elim~
inating crazing when PVC plasticized therewith is cGntacted with polystyrene sheets the following test was` conducted.
` 15 Samples (3/4" X 5-1/4") were cut parallel to the extrusion ~
' direction from 0.090-0.1000" extruded polystyrene sheet known by the Trade Mark of ~lonsanto HT-92. Flexural strength of this material was at least 7000 psi. Each sample was measured .. , ~, with a micrometer at its center for width and thickness `
dimensions. The sample was then wrappèd with the rear side in tension over a brass jig of radius 7.000+ .002l1 and taped to the ~ig at the ends. This assembly was then placed against the tail of the PVC test gasket and forced against it by apply-ing 20 inch-pounds torque to a 1/4"-16.bolt against the ~op of the jig. the assembly was immediately placed ln a chamber ~`
at 50 C. and stored for 4 hours. After immediate dlsassembly ~ ~
the styrene part was allowed to stand at romm temperature for ` ' , at least 15 minutes and then tested for flexural strength AST~ D-790), using a 1" span and crosshead motion of .05"
per minute. Strength was calculated from the equation~
'` ' ` ~ ` . . ' , ' `' ' ' ' ' - 10~ s93 ~
3 X load ' Strength (psi) = - - 2 2 (thickness) (width) Results are the average of at least 5 samples. Percent reteDtion of strength compared to unexposed polystyrene is `
s 5 then reported. Ninety percent or greater retention is con- .
, sidered excellent. ~`
.
, ~ :
- ' ' . ' . `
. ' : ' - , ,' . . '' . ` :
g . ' ' -- , , ` .
:
. ~ . .

~:' ` ' ' ' . ' .- . .~
~:. ' ' ' ' ' ' ' , , ,, ' ' , ' ' ";'' ~' ''.

~ . ' `'. ~' ' ''.' ' , `'' , "':' ',' '`' `' t . ~ . . . . . .. .. . . .

~.: . - . . ' , . :, ~`,'"`:" '` ',"' ' '. `'' " ' ' ', ','' ' ,'''~`,'~ ' .

,:
~'1 ` ~ ` ' . ' , ' ` ' ' '' ' 1`" ` ' ` '. ' ' . ' . ` , . . `

,'"`:. ` ' '' . .' ' ',' ~ '. .,~:

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- ~13a~
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l ;`. ., ` .
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l ~L~5~593 ~ ~
Results obtained were as follows; . ' I . ............. ............... .... :. -I PLASTICIZER OF EXAMPLE -STRE~\lGTH RETENTI021 (%) ::
I ~ - ` .
¦ I 9Q.4 I,V 92.9 96.1 ' ¦ , VI , 91.4 , `'' -I ., ' . . . . ~:
l EXA~LE X ' ` I -- - . . . '''` ' Additional testing was conducted with the P~C compositions ¦ ~lasticized with t~e polyesters prepared a~ove ~o demonstrate ~ , ¦ the superior migration characteristics, i.e. little`or no ~;
¦ tendency to migrate,' of these polyesters. In this instance I a ~ending form test was employed ~ith polystyrene resin.
I . ' ' ' . . . ' . .. .
¦ ~tress free molded polystyrene sheet (0.125 +.005"j was ;
l condi,tioned and tested ~in duplicatel in a room maintained ct ' ¦ 72~ F. ~1 F. and sa +2 percent RoH~ Strips of polystyrene ¦ (1/2''X 8"~ were cut with a circul,ar table saw using a veneer I type blaae taking care to prevent ~inger markina by handling ¦ onlx wi,th gloves. The edges of each test bar were then' ¦ scraped with a knife to re~ove burrs left from cutting. Each p~lystyrene test strip was wrapped in white mi~eograph paper ;;
~ and s,andwiched bet-~een glass plates and placed in a forced ¦ air oven (150 F.l for 24 hours. The assembled ~lass and , I strips were removed and allowed to cool to room temperature ¦ for at least 4 hours.
I , .
¦ Seven inch X 3/16" strips were,cut from the compounded ¦ ~ mil ~VC sheet and ~iped t~ith methanol to remove any con- ,;
¦ tamination., The smooth side o~ the vinyl strip was then placed directly a~ainst the polystyrene test strip and lisht pressure~
applied to the vinyl to insure good contact while centerina as close as possible on the test strip. The assembly was "
I then placed on the eliptical bending ~ar between the 18 and 12 ' ,~
mark~ and clamped so that the test strip conformed to the ~ I

I ` t ~ ~
I -,14- ' ' 1 - - ` ~
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.., ~. I ~

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, . ,.
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~051593 - `
. . .
contour of the b~nding bar. The bending form ~as placed horizontally on a table ~tith the test specimen up~ard and allowed to stand undisturbed for 4 days after which time the PVC test strip was removed. The point at which the pattern ~f crazing has stopped is then determined by visual examination and re-orted as inches of craze. The lower this value is the better the performance of the plasticizer. Results obtained employing the plasticizers of Examples I, IV, V and VI were ,' ,` ' , "' `' ` . ` " ' ,, '` ' . , , : , . ~ ~ ' .' ', ' .~','. '':' '''' . , . ' . ' ` ' . ' .: .
` . ' ' .. . . . .

~ ~ 15~
~ ~ ~ ' ",'` ' ~'""~ ,: ~
.: ~ ' ' ' ', , .~
:`-` . . . .
' . .. ~

Claims (11)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1, A polyester composition consisting essentially of a chain-terminated polyester having an average molecular weight between 1500 and 10000, said composition being obtained from the esterification of (a) an alpha-omega alkanedioic acid containing from 4 to 12 carbon atoms and (b) a branched chain dihydric alcohol containing from 4 to 10 carbon atoms and having only primary and secondary hydroxyl groups with (c) 3 to 15 mol percent, based on the total organic acids, of an aromatic mono-carboxylic acid containing from 7 to 20 carbon atoms.

2. The polyester composition of claim 1 wherein (a) is an aliphatic dicarboxylic acid containing 6 to 10 carbon atoms and wherein (b) is selected from the group consisting of:
2-hydroxymethyl-2-methylpropyl-2-hydroxymethyl 2-methyl-propionate, neopentyl glycol, 2-methyl-1,3-propane diol, 3-methyl-1,5-pentane diol, 2,2,4-trimethyl-1,3-pentane diol, 2,3-dimethyl, 2,3-butane diol, 1,2-propylene glycol, 1,3-butylene glycol, 1,2-butanediol, 1,2-pentanediol, 1,3-pentane-diol, 1,4-pentanediol.

3. The polyester composition of claim 1 wherein (a) comprises; an aliphatic saturated dicarboxylic acid containing 6 to 10 carbon atoms; and wherein (b) comprises 2-hydroxymethyl-2-mèthylpropyl-2-hydroxymethyl-2-methylpropionate having the structural formula:

4. The polyester composition of claims 1, 2, or 3 which has an average molecular weight in the range 2000 to 5000 and a viscosity at 210°F of 200 to 200 centistokes.

5. The polyester composition of claims 2 or 3 wherein (a) is adipic acid, azelaic acid or sebacic acid and (c) is benzoic acid or a C1-4 alkyl substituted benzoic acid.

6. The polyester composition of claims 2 or 3 wherein (a) is adipic acid, azelaic acid or sebacic acid and (c) is benzoic acid or a C1-4 alkyl substituted benzoic acid, wherein (c) constitutes 6 to 12 mol percent of the total organic acids.

7. The polyester composition of claims 2 or 3 wherein (a) is adipic acid, azelaic acid or sebacic acid and (c) is benzoic acid or a C1-4 alkyl substituted benzoic acid, wherein (c) constitutes 6 to 12 mol percent of the total organic acids and which has an average molecular weight in the range 2000 to 5000 and a viscosity of 210°F. of 200 to 250 centistokes.

8. An improved polymer composition comprising polyvinyl chloride homopolymer or polyvinyl chloride copolymer and 10 to 150 parts by weight per 100 parts vinyl resin of a chain-terminated polyester having an average molecular weight between l500 and 10000, said composition being obtained from the esterification of (a) an alpha-omega alkanedioic acid containing from 4 to 12 carbon atoms and (b) a branched chain dihydric alcohol containing from 4 to 10 carbon atoms and having only primary and secondary hydroxyl groups with (c) 3 to 15 mol percent, based on the total organic acids, of an aromatic monocarboxylic acid containing from 7 to 20 carbon atoms.

9. The polymer composition of claim 8 wherein the polyester has an average molecular weight in the range 2000 to 5000 and a viscosity at 210°F of 200 to 250 centistokes and is obtained from the esterification of (a) adipic acid, azelaic acid or sebacic acid and (b) a dihydric alcohol selected from the group consisting of 2-hydroxymethyl-2-methylpropyl-2-hydroxymethyl-2-methylpropionate, neopentyl glycol, 2-methyl-1, 3-propane diol, 3-methyl 1,5-pentane diol, 2,2,4-trimethyl-1,3-pentane diol, 2,3-dimethyl, 2,3-butane diol, 1,2 propylene glycol, 1,3-butylene glycol, 1,2-butanediol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol with (c) 6 to 12 mol percent based on the total organic acids of benzoic acid or C1-4 alkyl substituted benzoic acid.

10. The polymer composition of claim 8 wherein the polyester has an average molecular weight in the range 2000 to 5000 and a viscosity at 210°F of 200 to 250 centistokes and is obtained from the esterification of (a) adipic acid, azelaic acid or sebacic acid and (b) 2-hydroxymethyl-2-methylpropyl-2-hydroxymethyl-2-methylpropionate having the structural formula:

with (c) 6 to 12 mol percent based on the total organic acids of benzoic acid or C1-4 alkyl substituted benzoic acid.

11. The polymer eomposition of claims 8, 9, or 10 containing 30 to 110 parts polyester per 100 parts resin.