GB2344595A

GB2344595A - Poly epsilon-caprolactone plasticizers and vinylic polymer compositions plastified therewith

Info

Publication number: GB2344595A
Application number: GB9827427A
Authority: GB
Inventors: Dominique Grandjean; Andree Lahaye; Claude Dehennau
Original assignee: Solvay SA
Current assignee: Solvay SA
Priority date: 1998-12-11
Filing date: 1998-12-11
Publication date: 2000-06-14
Also published as: KR20010040862A; AU1983000A; GB9827427D0; EP1053283A1; CA2320046A1; CN1296514A; JP2003517045A; WO2000036009A1; BR9907824A

Abstract

Use of low molecular weight e -caprolactone homopolymers having an average molecular weight of at least about 500 g/mol. and no more than about 2000 g/mol. as a plasticizer for vinylic polymer compositions. The plasticizers may be incorporated into vinylic polymer compositions, such as PVC compositions and give the vinylic polymer composition into which they are incorporated properties approximating those which contain traditional plasticizers, such as DOP, DOA and TOTM while avoiding various disadvantages associated therewith.

Description

Poly s-caprolactone plasticizers and vinylic polymer compositions plastified therewith The present invention concerns plasticizers and vinylic polymer compositions, and in particular, poly s-caprolactone polymers (-PCL) and polyvinyl chloride (PVC) compositions having said plasticizers.

Many different organic molecules have been employed as plasticizers for vinylic polymer compositions, such as PVC. Notable among these plasticizers are phtalates, such as dioctylphtalate (DOP), adipates, such as dioctyl adipate (DOA) and trimellitates, and in particular trioctyl trimellitate (TOTM). Use of DOP and TOTM in particular are widespread for their advantageous properties of mechanical strength and permeability to 02 and C02.

While perhaps being the most preferred of those plasticizers now available, DOP, DOA and TOTM nonetheless also possess several properties which are disadvantageous and desireable to eliminate. One such property is the tendency for those plasticizers to escape or be extracted from the plasticized vinylic polymer composition (by, for example, volatilization and evaporation). This is particularly problematic when the composition is used in applications where it is exposed to elevated temperatures, such as an insulating medium for wires and cables, or to lipids (in the case of medical blood bags). Other such properties are that they are not biodegradable and that they have a tendency to absorb the active ingredients (such as diazepam) present in various medications, a property which is particularly problematic where medical perfusion bags are involved.

Furthermore, the consideration of phtalates (such as DOP) as being potentially toxic makes their use in medical devices, such as blood bags and perfusion bags problematic.

Accordingly, it has long been sought to identify other molecules which may serve as such plasticizers and which possess advantageous properties that approximate those positive properties of DOP, DOA and TOTM while not possessing the disadvantageous properties of DOP, DOA and TOTM.

In this regard, the use of specific polycaprolactones (capro-3 lactone and capro-4 lactone) are known as being useful as a plasticizer in replacement of DOP, TOTM and other such molecules.

For example, United States patent number 3, 592, 877 discloses plasticized thermoplastic vinylic resins plasticized with a plasticizing amount of relatively high molecular weight, solid, linear polymers of lactones, including poly capro-3 lactone and capro-4 lactone copolymers.

Similarily, Derwent publications 84-265927/43 (of Japanese patent application published 59/161419-A) and 86-192285 (ofJapanese patent application published 61/123645-A) disclose compositions having grafted PVC/polycaprolactone copolymers. The former discloses a PVC obtained either by grafting vinyl chloride onto polycaprolactone or by grafting a mixture of vinyl chloride and another comonomer onto polycaprolactone. The latter discloses kneading of, inter alia, PVC with polycaprolactone. While both disclosures state that the average molecular weight of the PCL as being between 103 and 106, these polycaprolactones are essentially of a relatively high molecular weight.

Further, Derwent publication 88-230506/33 (of Japanese patent application published 63/162721-A) discloses modified polycaprolactones having relatively high molecular weights of 1000-55000.

While being useful, those polycaprolactones having relatively high molecular weights crystallize rapidly into the polymer matrix causing an important loss in the plastification and a loss of transparency of the polymeric composition.

Finally, WO 94/11445 discloses polymeric compositions comprised of a structural polymer and at least one oligomer as a plasticizer. The structural polymer, which may be PCL, has an average molecular weight of 50000. The oligomer, which has an average molecular weight of 2000 or less, is apparently an oligohydroxy-alkanoate (OHA).

Accordingly, it can be seen that there remains a need to identify and provide a plasticizer for vinylic polymer compositions, and in particular for PVC compositions, which does not crystallize into the polymer matrix and which avoids the disadvantages experienced with DOP, DOA and TOTM but which gives results which approximate those of DOP, DOA and TOTM.

A primary goal of the present invention is to provide a plasticizer for vinylic polymer compositions, and in particular for PVC compositions, which does not crystallize rapidly into the polymer matrix, which does not give plate out and which avoids the disadvantages experienced with DOP, DOA and TOTM but which gives results which approximate those of DOP, DOA and TOTM.

Another primary goal is to provide a vinylic polymer composition, and in particular a PVC composition, which includes the plasticizer.

Still other goals are to provide a process for making the said composition plasticized with the said plasticizers and to provide for usage of the said compositions.

In accordance with the teachings of the present invention, disclosed herein is the use of low molecular weight e-caprolactone homopolymers as a plasticizer for vinylic polymer compositions. These -caprolactone homopolymers have an average molecular weight of at least about 500 g/mol. These -caprolactone homopolymers further have an average molecular weight of no more than about 2000 g/mol.

As used herein, the term"plasticizer"is used to refer to those liquids or solids which lower the glass transition temperature (Tg) of the vinylic/vinyl polymers and polymer compositions of the present invention.

As used herein, the term"low molecular weight -caprolactone"refers to those polyesters derived from s-caprolactone which terminate in at least one hydroxy group and that have an average molecular weight of no more than about 2000 g/mol.

Preferably, the"low molecular weight s-caprolactone"are polyol polyesters derived from e-caprolactone which terminate in hydroxy groups that have an average molecular weight of no more than about 2000 g/mol.

Preferably, the low molecular weight -caprolactone homopolymers have an average molecular weight of at least about 800 g/mol. More preferred, the low molecular weight -caprolactone homopolymers have an average molecular weight of at least about 900 g/mol. Also preferred is that the low molecular weight -caprolactone homopolymers have an average molecular weight of at least about 1100 g/mol. Most preferred are low molecular weight -caprolactone homopolymers having an average molecular weight of at least about 1000 g/mol.

Preferably, the low molecular weight s-caprolactone homopolymers have an average molecular weight of no more than about 1500 g/mol. More preferred are low molecular weight -caprolactone homopolymers having an average molecular weight of no more than about 1100 g/mol. Also preferred is that the low molecular weight e-caprolactone homopolymers have an average molecular weight of no more than 900 g/mol. Most preferred are low molecular weight - caprolactone homopolymers having an average molecular weight of no more than about 1000 g/mol.

The low molecular weight s-caprolactone homopolymers are preferably linear homopolymers. Also preferred are branched homopolymers having at least one short branching chain.

As used herein, the term"short branching chain"refers to those chains which have no more than twelve (12) atoms of carbon.

In further accordance with the teachings of the present invention, disclosed herein is a vinylic polymer composition having a vinylic (homo or co) polymer and a plasticizing amount of the said low molecular weight -caprolactone homopolymer. These e-caprolactone homopolymers have an average molecular weight of at least about 500 g/mol. These -caprolactone homopolymers further have an average molecular weight of no more than about 2000 g/mol.

As used herein, the term"vinylic polymers"and"vinyl polymers"are used to refer to those homopolymers and copolymers of halogenated monomers and, in particular, those homo and copolymers of halogenated monomers such as vinylidene fluoride, vinyl fluoride, vinyl chloride and vinylidene chloride as well as the copolymers of these halogenated monomers and at least one other ethylenically unsaturated monomer.

As used herein, the terms"vinylic polymer compositions"and"vinyl polymer compositions"refers to those compositions which include at least 50% (w/w) of vinyl homopolymers or copolymers.

Preferably, the vinylic (homo or co) polymer includes a halogenated vinyl (homo or co) polymer with vinyl chloride (homo or co) polymers being more preferred. Most preferred are polyvinyl chloride (homo or co) polymer. Among homopolymers, polyvinylchloride is preferred. Among copolymers, vinylchloride/vinyl acetate (VC/VAc) copolymers are preferred.

As used herein, the terms"halogenated vinyl polymers"and"halogenated vinylic polymers"are used to refer to homopolymers and copolymers of halogenated vinyl monomers, such as vinyl chloride, vinylidene chloride, vinylidene fluoride and vinyl fluoride. Examples of such copolymers include copolymers of the two or more of these halogenated vinyl monomers and copolymers of at least one of these halogenated monomers and at least one other monomer containing ethylenic unsaturation, such as vinyl esters like vinyl acetate, acrylic or methacrylic esters, nitriles and amides.

As used herein, the term"vinyl chloride polymer"is used to refer to both homopolymers of vinyl/vinylic chloride monomers, such as vinyl chloride and vinylidene chloride, and copolymers of such vinyl/vinylic chloride monomers and at least one other ethylenically unsaturated monomer which can be polymerized by radical polymerization. Mention may be made, as examples of conventional comonomers of vinyl chloride which can be employed in the process of the present invention, of olefins, halogenated olefins, vinyl ethers, vinyl esters, such as vinyl acetate (VAc) and acrylic esters, nitriles and amides.

The comonomers are employed in amounts not exceeding 50 molar % and, generally 35 molar % of the mixtures employed in the copolymerization.

As used herein, the term"polyvinyl chloride"is used to refer to both homopolymers of vinyl chloride monomers and copolymers of vinyl chloride monomers and at least one other ethylenically unsaturated monomer which can be polymerized by radical polymerization. Mention may be made, as examples of conventional comonomers of vinyl chloride which can be employed in the process of the present invention, of olefins, halogenated olefins, vinyl ethers, vinyl esters, such as vinyl acetate (VAc) and acrylic esters, nitriles and amides.

Among such VC/VAc copolymers, preferred are such VC/VAc copolymers having more than about 2% (w/w) VAc. Particularly preferred are such copolymers having about 6% (w/w) VAc. Further preferred are such copolymers having no more than about 12% (w/w) VAc.

If desired, the formulation can also have stabilizers, lubricants, fillers and processing aids, as is commonly known in art.

The concentration of the low molecular weight E-caprolactone homopolymers in the vinylic polymer compositions of the present invention can be varied as desired and needed.

Preferably, the concentration of the low molecular weight s-caprolactone homopolymers in the vinylic polymer compositions of the present invention be at least about 0. 5 phr (per hundred parts of PVC resin (w/w)). Further preferred is that the concentration of the low molecular weight E-caprolactone homopolymers in the vinylic polymer compositions of the present invention be at least about 10 phr. Also preferred is that the concentration of the low molecular weight s-caprolactone homopolymers in the vinylic polymer compositions of the present invention be at least about 60 phr. Most preferred is that the concentration of the low molecular weight e-caprolactone homopolymers in the vinylic polymer composition be at least about 55 phr.

Preferably, the concentration of the low molecular weight e-caprolactone homopolymers in the vinylic polymer compositions of the present invention be no more than about 65 phr. Further preferred is that the concentration of the low molecular weight e-caprolactone homopolymers in the vinylic polymer compositions of the present invention be no more than about 60 phr. Also preferred is that the concentration of the low molecular weight s-caprolactone homopolymers in the vinylic polymer compositions of the present invention be no more than about 10 phr. Most preferred is that the concentration of the low molecular weight e-caprolactone homopolymers in the vinylic polymer composition be no more than about 55 phr.

In another aspect of the present invention, disclosed herein is a process for making the vinylic polymer compositions of the present invention. This process includes the steps of : mechanically blending resins of the vinylic polymers of the present invention with resins of the e-PCL of the present invention and, if present, the usually used additives such as stabilizers, fillers, lubricants, processing aids, whereby a dry powder blended composition of vinylic polymer/s-PCL resin/additives is formed, compounding the dry powder blend of vinylic polymer/s-PCL resin/additives, whereby a compound of vinylic polymer/E-PCL resin/additives is formed, and of extruding or injecting the compound of vinylic polymer/e-PCL resin/additives, whereby a finished article is obtained.

If desired this process may further include the step of grinding the blended compounded vinylic polymer/E-PCL resin (before extrusion), whereby a ground vinylic polymer/s-PCL resin is formed.

In still another aspect of the present invention, disclosed herein is the use of the plasticized vinylic polymer compositions of the present invention for the fabrication of formed products.

As used herein, the terms"plasticizing amount"and"plasticizing quantity" refer to that amount or quantity of the plasticizer which is needed to lower the glass transition temperature of the homopolymer/copolymer composition into which the plasticizer is incorporated.

As used herein, the terms"plasticized vinyl polymer","plasticized vinylic polymer","plasticized vinyl polymer composition"and"plasticized vinylic polymer composition"refer to those vinylic/vinyl polymers and vinylic/vinyl polymer compositions, which have at least one plasticizer incorporated therein.

A particular aspect of the present invention is the specific choice of a particular type of plasticizer for vinylic polymer compositions, and in particular for PVC, which avoids the disadvantages associated with the use of DOP, DOA and TOTM while possessing the advantages thereof.

The plasticizers of the present invention are low molecular weight e-caprolactone homopolymers. These e-caprolactone homopolymers have an average molecular weight of at least about 500 g/mol. These e-caprolactone homopolymers further have an average molecular weight of no more than about 2000 g/mol.

Preferably, the average molecular weight of the low molecular weight s-caprolactone homopolymer plasticizers of the present invention is at least about 800 g/mol. More preferred is that the average molecular weight of the low molecular weight -caprolactone homopolymer plasticizers of the present invention is at least about 900 g/mol. Also preferred is that the average molecular weight of the low molecular weight e-caprolactone homopolymer plasticizers of the present invention is at least about 1100 g/mol. Most preferred is that the average molecular weight of the low molecular weight e-caprolactone homopolymer plasticizers of the present invention is about 1000 g/mol.

Preferably, the average molecular weight of the low molecular weight e-caprolactone homopolymer plasticizers of the present invention is no more than about 1500g/mol. More preferred is that the average molecular weight of the low molecular weight e-caprolactone homopolymer plasticizers of the present invention is no more than about 1100 g/mol. Also preferred is that the average molecular weight of the low molecular weight e-caprolactone homopolymer plasticizers of the present invention is no more than about 900 g/mol. Most preferred is that the average molecular weight of the low molecular weight s-caprolactone homopolymer plasticizers of the present invention is no more than about 1000 g/mol.

As used herein, the term"E-caprolactone"refers to internal esters of hydroxycaproic acid.

As used herein, the term"Poly s-caprolactone"refers to those polyesters derived from e-caprolactone and which terminate in at least one hydroxy group.

As used herein, the terms"Poly e-caprolactone homopolymer"and "s-caprolactone homopolymers"refers to those polyesters derived from s-caprolactone and which terminate in at least one hydroxy group and has only s-caprolactone units having the following formula :

It is noted that the low molecular weight e-caprolactone homopolymers of the present invention may be either linear or branched. In those cases where branched polymers are involved, it is preferred that the polymer has a principle branch with at least one short branching chain. Linear polymers are preferred.

A particularly preferred low molecular weight s-caprolactone homopolymers of the present invention is that preferred low molecular weight e-caprolactone homopolymers sold under the name CAPAs 214 (SOLVAY INTEROX Ltd.).

The use of the E-PCL plasticizers of the present invention provide advantages over the use of DOP, DOA and TOTM in that it is biodegradable, and nontoxic while still possessing good properties : properties of mechanical strength, low exsudation, low permeability to 02 and CO2 and low fogging.

The low molecular weight e-caprolactone homopolymers of the present invention, such as CAPAs 214, have a low polydispersity (preferrably, are substantially monodispersed). These properties result in the presence of small amounts of oligomers of low molecular weight in the mixture, thereby reducing exsudation.

As used herein, the term"monodispersed"refers to a E-PCL which has only one molecular mass.

As used herein, the term"substantially monodispersed"refers to a E-PCL which has a polydispersity of more than about 1 but no more than about 1. 7.

As used herein, the term"low polydispersity"refers to a s PCL which has a polydispersity of no more than about 1. 7.

Preferably, the low molecular weight e-caprolactone homopolymers of the present invention have a polydispersity of no more than about 1. 7. Further preferred are those low molecular weight e-caprolactone homopolymers of the present invention have a polydispersity of about 1. 3. Most preferred are those low molecular weight e-caprolactone homopolymers which have a polydispersity of about 1.

The vinylic polymer is, preferably, a halogenated vinyl polymer, such as PVDC, PVDF, etc.. Particularly preferred is that the vinylic polymer is polyvinyl chloride.

The vinylic polymers of the present invention may be either homopolymers or copolymers. Preferred among homopolymers is polyvinylchloride. Preferred among copolymers is vinylchloride/vinyl acetate (VC/VAc) copolymers.

Among such VC/VAc copolymers, preferred are such VC/VAc copolymers having more than about 2 % (w/w) VAc. Particularly preferred are such copolymers having about 6 % (w/w) VAc. Further preferred are such copolymers having no more than about 12 % (w/w) VAc.

If desired, the formulation can also have stabilizers, lubricants, fillers and processing aids, as is commonly known in the art.

The vinylic polymer compositions of the present invention may be fabricated in the same manner as that presently utilized for fabricating vinylic polymer compositions which have DOP, DOA and TOTM as plasticizers. That is to say, making of the plasticized vinylic polymer compositions of the present invention includes the steps of obtaining resins of the s-PCL and the vinylic polymer, mechanically blending the two resins, whereby a blended resin is obtained, compounding the PCL/vinylic polymer resins (i. e., with an intenal mixer), whereby a blended compounded resin is formed, and extruding the blended and compounded PCL/vinylic polymer resin, whereby the vinylic polymer compositions of the present invention are formed into the final product desired.

The vinylic polymer compositions of the present invention may be further fabricated by grinding the blended, compounded PCL/vinylic polymer resins (before extruding), whereby a ground blended and compounded resin is formed.

Extrusion may be either monoextrusion or coextrusion, as desired or needed.

These vinylic polymer compositions may be obtained either already prepared or they may be prepared themselves by polymerization, such as suspension, emulsion and/or microsuspension polymerization, under conditions well known to those skilled in the art. Examples of such polymerization conditions are set forth in and can be found by reference to the Encyclopedia of PVC, 2nd edition, (Nass and Heiberger, eds.), Vol. 1 (Mariel Dekker, Inc.).

The plasticized vinylic polymer compositions of the present invention may be used for any number of purposes, well known to those skilled in the art, for which vinylic polymer compositions which have been plasticized with DOP, DOA and/or TOTM may be use. Examples, include the use of the plasticized vinylic polymer composition for the production of films for food wrapping, cables, medical pouches and bags (i. e., blood and perfusion bags) and automobile parts (such as dashboards, sideboards, etc), medical tubes (associated with medical packs and pouches), catheters, drains, etc., baby bottles, dummies for babys and dental bands.

In this regard, it is noted that when plasticized vinylic polymer compositions of the present invention may be used in complex multilayer structures formed by coextrusion, coinjection (such as for toys) and extrusion lamination to form articles having the plasticized vinylic polymer compositions included in at least one face. Such structures are particularly applicable where the formation of toys and medical or food bags are involved. Preferably, the non contacting layer (that is to say, the layer that is not in contact with the body of the user such as in the case of toys, or drug materials, such as solutions which are contained in, for example, medical pouches, etc.) is made with DOP, DOA or TOTM plasticized PVC.

Having thus described the plasticizers of the present invention, vinylic polymer compositions plasticized therewith, the process for the fabrication thereof and the use of such plasticized vinylic polymer compositions for the fabrication of various articles of manufacture, we now turn to the following examples which are illustrative of the present invention only and are not meant to, nor should they be taken as, limiting the scope of the present invention.

Example 1 A low molecular weight poly e-caprolactone homopolymer plasticizer available from SOLVAY INTEROX Limited under the name CAPA) 214 was obtained. CAPAe 214 is a diol-type, linear homopolymer having an average molecular weight of about 1000 g/mol. As such, CAPA6 214 is an example of a relatively low molecular weight poly s-caprolactone homopolymer plasticizer of the present invention.

For comparative purposes, conventional plasticizers DOP (sold under the trademark PALATINOL AH by BASF) and TOTM (sold under the trademark DIPLAST TM/ST by Lonza) were obtained.

For further comparative purposes, two high molecular weight poly e-caprolactone homopolymer plasticizers were also obtained from SOLVAY INTEROX Ltd. available, respectively, under the marks CAPAX 231 and CAPAs 240. CAPA8) 231 is a diol-type of linear homopolymer having an average molecular weight of about 3000 g/mol. CAPA 240 is a diol-type of linear homopolymer having an average molecular weight of about 4000 g/mol.

A polyvinyl chloride polymer composition, sold under the mark SOLVIC 271 GC (SOLVAY (S. A.)) was obtained. This PVC polymer composition is a polyvinylchloride homopolymer having a viscosity of 129 dm3/kg (measured according to Norm ISO 174).

Using each of the five (5) plasticizers, obtained as described above, five respective formulations were prepared having the following compositions : Formulation 1 (according to the present invention) : PVC resin (SOLVIC 271 GC) : 100 phr Poly E-caprolactone (CAPAe 214) : 55 phr Epoxidated soya oil : 5 phr Zinc stearate : 0. 4 phr Calcium stearate : 0. 2 phr phr = per hundred parts of PVC resin (w/w) (all is in comparison to the PVC resin which equals 100 phr).

Formulation 2 (comparative formulation) Formulation 2 was identical to Formulation 1 with the sole exception that in Formulation 2, instead of 55 phr poly s-caprolactone (CAPAs 214) as a plasticizer, 45 phr DOP was used as the plasticizer.

Formulation 3 (comparative formulation) Formulation 3 was identical to Formulation 1 with the sole exception that in Formulation 3, instead of 55 phr poly -caprolactone (CAPAg) 214) as a plasticizer, 55 phr TOTM was used as the plasticizer.

Formulation 4 (comparative formulation) Formulation 4 was identical to Formulation 1 with the sole exception that in Formulation 4, instead of 55 phr low molecular weight poly e-caprolactone (CAPA'214) as a plasticizer, 55 phr of a high molecular weight poly s-caprolactone (CAPA 231) having an average molecular weight of about 3000g/mol. was used as the plasticizer.

Formulation 5 (comparative formulation) Formulation 5 was identical to Formulation 1 with the sole exception that in Formulation 5, instead of 55 phr low molecular weight poly s-caprolactone (CAPA2) 214) as a plasticizer, 55 phr of a high molecular weight poly e-caprolactone (CAPA 240) having an average molecular weight of about 4000 g/mol. was used as the plasticizer.

The finished articles used for evaluation were prepared from respective formulations as described below : In the blending step, the respective resin powders of the vinylic polymer (the PVC) and the solid additives (zinc and calcium starate) were placed in the blending drum and blending commenced. When, under the effect of friction, the temperature of the resin mixture reached 80 C, the additives and plasticizers were added and the blending continued until the moment when the temperature of the mixture reached about 115 C-120 C. The blending was then gradually slowed to permit the resin mixture to cool until the resin mixture reached about 40 C-50 C when all blending was ceased and the resin blend was removed from blending drum.

In the compounding step, the resin blends of formulations 1, 2 and 3, which had been removed from the blending drum, were compounded (on GK) at a temperature of 145 C for about 3 minutes, whereby a resin cake was obtained.

The resin cakes were then cut-up into strips and granulated.

In the extrusion step, the granulated resin from the compounding step were fed into a monoscrew extruder (TROESTER UP30, 20D) equipped with a tubular die. The tube obtained was inflated and calibrated to an external diameter of 32 mm. The extrusion conditions were as follows : Barrel temperatures : zone 1 : 143 C zone 2 : 160 C zone 3 : 161 C zone 4 : 169 C Die temperature : 180 C Screw speed. 40 revolutions per minute (rpm) Using the above-described process, the e-caprolactone homopolymer plasticized vinylic polymer composition of the present invention was fabricated (from Formulation 1).

Similarily, using the same process, comparative plasticized vinylic polymer compositions having the different plasticizers were also fabricated (from formulations 2-3).

The resin blends of formulations 4 and 5 which had been removed from the blending drum, were compounded (on a Brabender internal mixer) at a temperature of 170 C for about 10 minutes and pressed, whereby a pressed resin cake was obtained.

Example 2 A measurement of elasticity (stretching until rupture at ambient temperature) was performed on the e-caprolactone homopolymer plasticized vinylic polymer composition of the present invention (made from formulation 1) and on those plasticized vinylic polymer compositions having other plasticizers (made from formulations 2 and 3).

This evaluation was performed following the procedure set forth in Norm ISO 527 on film (with extensionmeter-100 mm between grips).

The percentage of lengthening of each polymer composition until breaking was : Composition &num;1 (PVC/CAPA 214) : 279% Composition &num;2 (PVC/DOP) : 222% Composition&num;3 (PVC/TOTM) : 285% Example 3 An evaluation of elastic modulus at ambient temperature was performed on the s-caprolactone homopolymer plasticized vinylic polymer composition of the present invention (made from formulation 1) and on those plasticized vinylic polymer compositions having other plasticizers (made from formulations 2 and 3).

This evaluation was performed following the procedure set forth in Norm ISO 527 on film (without extensionmeter-100 mm between grips).

The results obtained were : Composition &num;1 (PVC/CAPAs 214) : 13. 9 MPa (Mega Pascal) Composition &num;2 (PVC/DOP). 18. 1 MPa (Mega Pascal) Composition &num;3 (PVClTO'TIvn : 18. 1 MPa (Mega Pascal).

Example 4 A determination of Tg by DMTA was performed on the e-caprolactone homopolymer plasticized vinylic polymer composition of the present invention (made from formulation 1) and on those plasticized vinylic polymer compositions having other plasticizers (made from formulations 2 and 3).

The measure of the DMTA was performed in traction (tensile) apparatus (POLYMER LABORATORIES) set at a frequency of 1 Hz and with a temperature increase of 3 C/minute in a temperature range of from-50 C to 200 C.

The Tg determined in this manner were as follows : Composition &num;1 (PVC/CAPA) 214) :-8. 15 C Composition &num;2 (PVC/DOP) :-9. 95 C Composition &num;3 (PVC/TOTM) :-7. 6 C Example 5 A measurement of dynamic viscosity in melted state was performed on the e-caprolactone homopolymer plasticized vinylic polymer composition of the present invention (made from formulation 1) and on those plasticized vinylic polymer compositions having other plasticizers (made from formulations 2 and 3).

The measure of the dynamic viscosity of the compositions in their melted states was performed on an ARES rheometer (Rheometric Scientific) having 25 mm diameter plates arranged in parallel, one above the other. The samples were introduced between the plates and heated at 190 C for about 10 minutes.

While the upper plate remains stationary, the lower plate was rotated (turned) at a frequency of about 10-1 rad/second until a strain of 10% was imposed.

The results obtained in this manner were as follows : Composition &num;1 (PVC/CAPA (2 214) : 1. 6 104 Pa. s (Pascal. second) Composition &num;2 (PVC/DOP) 1. 3 104Pa. s (Pascal. second) Composition&num;3 (PVC/TOTM) 104Pa. s (Pascal. second).

Example 6 A measurement of fogging was performed on the e-caprolactone homopolymer plasticized vinylic polymer composition of the present invention (made from formulation 1) and on those plasticized vinylic polymer compositions having other plasticizers (made from formulations 2 and 3).

Fogging is a problem that results from the exsudation and evaporation of the plasticizer under the effects of heat.

The measure of the amount of fogging was determined by gravimetry.

Respective two gram samples of the respective polymer compositions were deposited in a receptacle which was then covered by a aluminium sheet. This cell was then maintained for 16 hours at about 100 C.

During the 16 hours, the plasticizer in the respective polymer compositions progressively evaporated and condensed on the aluminium. At the end of this 16 hours period, the aluminium paper was removed from the receptacle and weighed.

Using the weight of 2 grams of the sample as a baseline, the percentage of plasticizer (by comparison with the initial 2 gram quantity of the original) which is found on the aluminium paper was determined. These results were as follows : Composition &num;1 (PVC/CAPA 214) : 0. 16% (w/w) Composition &num;2 (PVC/DOP) : 0. 54% (w/w) Composition &num;3 (PVC/TOTM) : 0. 05% (w/w) Example 7 A determination of the permeability of the various compositions to 02 and C02 was made on the e-caprolactone homopolymer plasticized vinylic polymer composition of the present invention (made from formulation 1) and on those plasticized vinylic polymer compositions having other plasticizers (made from formulations 2 and 3).

The measurements of the permeability were performed following the procedure set forth in Norm ISO/CD 15105-2 : (E) attemperatures of 23 C, 35 C and 50 C.

The results of these measurements of permeability of the various compositions to 02 (expressed in cm3 mm/m2 24H atm) are set forth below in Table 1.

Table 1 Permeability to O2

....................

Composition 23 C 35 C 50 C Composition #1 60 170 340 (PVC/CAPA *214) Composition &num;2 230 430 550 (PVC/DOP) Composition &num;3 340 900 1010 (PVC/TOTM) The results of these measurements of permeability of the various compositions to C02 (expressed in cm3-mm/m2 24H atm) are set forth below in Table 2.

Table 2 Permeability to C02

Composition 23 C 35 C 50 C Composition &num;1 660 1280 2560 (PVC/CAPA) 214) Composition &num;2 1330 2440 4460 (PVC/DOP) Composition &num;3 1840 3090 5230 (PVC/TOTM) Example 8 A determination of the exsudation properties of the relatively low molecular weight e-caprolactone homopolymer plasticized vinylic polymer composition of the present invention (made from formulation 1), on those plasticized vinylic polymer compositions having other plasticizers (made from formulations 2 and 3) and on those having the relatively high molecular weight e-caprolactone homopolymer plasticized vinylic polymer compositions (made from formulations 4 and 5) was performed.

The respective polymer compositions were stored at ambient temperature and humidity with visual observations thereof being made at regular intervals of one week starting one week after storage commenced.

Visual observation of the respective samples revealed that, those vinylic polymer compositions having the relatively high molecular weight e-caprolactone homopolymer plasticizer (made from formulations 4 and 5) displayed an important exsudation of the plasticizer after about 6 days which increased over time. This exsudation resulted in the polymer composition becoming opaque. Contrary thereto even after approximately eight months, the composition of the present invention (composition &num;1) and compositions &num;2 and 3 were still totally transparent and no exsudation of the plasticizer was observed.

Example 9 The ability of the various compositions to withstand sterilization by water vapor was measured on the relatively low molecular weight s-caprolactone homopolymer plasticized vinylic polymer composition of the present invention (made from formulation 1) and on those plasticized vinylic polymer compositions having other plasticizers (made from formulations 2 and 3).

Sheaths (films) of the compositions were welded by high frequency for forming bags having pockets of 100ml. The bags were then filled with respective 60ml samples of demineralized water, sealed and then sterilized by water vapor for 30 minutes at 120 C with compensation for pressure during cooling.

The ability of the formulations was substantially identical, being opaque when exiting the sterilizer due to water which had penetrated into the walls and becoming transparent within the next 24 hours.

However, the walls of the bags of formulations 2 and 3 which were in contact during the sterilization permanently fused together while the walls of the bag of formulation 1 did not. The walls of the bag of formulation 1 lightly adhere together and can be separated by simply pulling. This presents an important advantage in the field of medical bags which must, in fact, be either first filled or expanded with helium before sterilization.

Example 10 A determination of the ability of the compositions to act as a barrier to DOP was performed on the relatively low molecular weight E-caprolactone homopolymer plasticized vinylic polymer composition of the present invention (made from formulation 1).

Four sheets of PVC/DOP, each having 30% (w/w) of DOP and a constant thickness of 350 pm, were obtained. The composition of formula 1 was formed into three respective sheets of PVC/s-PCL, each having a thickness of about 100 um. Each of the films of formula 1 were then laminated onto a respective film of PVC/DOP and each of the laminated sheets then stored at a respective temperature of 23 C, 37 C and 55 C.

To measure the barrier to DOP, the laminated sheets were cut up into a 60 mm disk which was placed into a brass cell (Laitron cell) having two chambers, one above the other. The laminated sheets of the composition of formula 1 and of those formulas containing DOP were placed between the two chambers and the upper chamber was filled with n-hexane (a DOP solvent) which is in contact with the PVC/s-PCL compositions or the PVC/DOP for the reference. The cell was then agitated for 1 minute at ambient temperature to remove the DOP from the surface of the film. An aliquot of n-hexane was taken and the DOP present therein was measured by gas chromatography (g/m2).

A first measurement was performed after 24 hours of storage. Other measurements were performed after 8, 15, 22, 29, 36, 43, 57, 64 and 71 days of storage. The results of these measurements are presented below in Table 3.

Table 3

days after storage 23 C 37 C 55 C 1 0.08 0.125 0.235 8 0.165 0.31 0.47 15 0. 19 0. 395 0. 775 22 0. 185 0. 46 0. 735 29 0. 39 0. 7 0. 865 36 0. 37 0. 8 0. 91 43 0. 43 0. 87 0. 82 57 0. 495 0. 81 0. 945 64 0. 465 0. 895 0. 84 71 0. 515 0. 885 0. 865 Reference DOP n. d. 4 4 (1 day) n. d. = not determined The results of this test, clearly demonstrate the ability of the relatively low molecular weight e-caprolactone homopolymer plasticized vinylic polymer composition of the present invention (made from formulation 1) to considerably limit the migration Qf DOP towards the surface of the article.

Claims

1-Use of low molecular weight e-caprolactone homopolymers as a plasticizer for vinylic polymer compositions characterized by said e-caprolactone homopolymers having an average molecular weight of no more than about 2000 g/mol.

2-The use of the low molecular weight -caprolactone homopolymers according to claim 1, further characterized in that the low molecular weight -caprolactone homopolymers have an average molecular weight of about 1000 g/mol.

3-The use of the low molecular weight -caprolactone homopolymers according to claims 1 or 2, further characterized in that the low molecular weight -caprolactone homopolymers have an average molecular weight of at least about 500 g/mol.

4-The use of the low molecular weight -caprolactone homopolymers according to any of claims 1 to 3, further characterized in that the low molecular weight s-caprolactone homopolymers are linear homopolymers.

5-The use of the low molecular weight e-caprolactone homopolymers according to claims 1 to 4, further characterized in that the low molecular weight -caprolactone homopolymers are substantially monodispersed.

6-The use of the low molecular weight e-caprolactone hamopolymers according to claims 1 to 3, further characterized in that the low molecular weight E-caprolactone homopolymer is branched having at least one short branching chain.

7-A vinylic polymer composition having a vinylic polymer and a plasticizing amount of a plasticizer, characterized in that the plasticizer is a low molecular weight e-caprolactone homopolymer having an average molecular weight of no more than about 2000 g/mol.

8-The vinylic polymer composition according to claim 7, further characterized in that the plasticizer is a low molecular weight -caprolactone homopolymer having an average molecular weight of at least about 500 g/mol.

9-The vinylic polymer composition according to either of claims 7 or 8, further characterized in that the plasticizer is any of the low molecular weight e-caprolactone homopolymers of claims 1 to 8.

10-The vinylic polymer composition according to any of claims 7 to 9, further characterized in that the vinylic polymer is a halogenated vinyl polymer.

11-The vinylic polymer composition according to any of claims 7 to 9, further characterized in that the vinylic polymer is a vinyl chloride polymer.

12-The vinylic polymer composition according to any of claims 7 to 11, further characterized in that the vinylic polymer is polyvinyl chloride.

13-The vinylic polymer composition according to any of claims 7 to 12, further characterized in that the vinylic polymer is a polyvinyl chloride/vinyl actetate copolymer.

14-The vinylic polymer composition according to any of claims 7 to 13, further characterized in that the plasticizer is present in a quantity of about 55 phr.

15-A process for making the vinylic polymer compositions according to any of claims claims 7 to 14 characterized by the steps of mechanically mixing the said vinylic polymer resin with the resin of a low molecular weight s- caprolactone homopolymers having an average molecular weight of no more than about 2000 g/mol, compounding the mixed resins and extruding the mixed resins, whereby the plasticized vinylic polymer composition is obtained.

16-Use of the plasticized vinylic polymer compositions according to any of claims 7-14 for the fabrication of formed products.

17. A vinylic polymer composition comprising an c-caprolactone homopolymer having an average molecular weight of no more than 2000mol substantially as hereinbefore described with reference to Example 1.