POLYOL ESTER PVC PLASTICIZERS

Abstract: Plasticized PVC compositions are disclosed which are heat resistant and which exhibit low smoke generation where the platicizer is a pentaerythritol ester of mixed C5, C7 and C9 alkanoic acids.

Description: POLYOL ESTER PVC PLASTTCTZERS This invention reiates to compositions that are useful as piasticizers for thermoplastic poiyvinvlchloπde (commonly referred to as PVC). More particularly, it reiates to piasticizers for PVC intended for use in high temperature resistant applications and which are characterized as having iow smoke generating properties. Poiy( vinyl chloride), hereafter referred to as PVC, is extensively used in many applications. In use. PVC is plasticized to permit it to be processed into a flexible material. In addition, other additives such as thermal stabilizers, lubricants, pigments, fillers, impact modifiers, and flame retardants are generally employed to produce PVC compositions having desired properties. Despite its thermal instability, unmodified PVC has relatively good flame retardant properties due to its high chlorine content. However, the piast-άzer necessary for flexibility and good processing properties generally increases the flammabiiity of PVC compositions, especially if used at high levels. Moreover, when PVC bums, it produces considerable smoke, and the addition of some flame retardants to plasticized compositions to reduce their flammabiiity generally increases smoke generation upon burning. It is desirable to have a PVC plastiάzer which is compatible with the resin and provides to the composition the required physical properties and at the same time exhibits iow smoke generating properties, obviating the need for special smoke suppressant additives. Poiyoi esters have been used in PVC compositions as disclosed, for example, in U.S. Patent 4.605.694 (issued August 12, 1986 to Walker), where they are taught for use in combinauon with tπ eilitate as an extender and secondary piastiάzer. U.S. Patent 4,421.886 (issued Dec 20, 1983 to Worschek et al.) discloses PVC compositions, where the partial ester of pentaerythritol is used in combination with a poiybasic lead compound as a stabilizer-lubricant combination. German application 1618586 (published April 1, 1971) in the abstract makes a general disclosure that paniai esters of pentaerythritol are useful as piasticizers and stabilizers for polymers. The present invention is based on the discovery that pentaerythritol, when ully esteriήed with a mixture of certain alkyl carboxylic acids, provides a heat resistant PVC piasticizer which is compatible with PVC over a range of 20-70 phr (parts by weight per hundred pans by weight of resin), and which exhibits desirable low smoke generating properties when measured in accordance with ASTM E-662. According to the invention, there has been discovered heat-resistant, low smoke-generating plasticized PVC blended with a piasticizing composition characterized in that the piasticizing composition is in an amount of about 20-70, such as 50-70, e.g., wire formulations are typically 30-35, phr and consists essentially of a pentaerythritol alkanoic add ester, wherein the alkanoic add is a mixture of C5, C7, and C9 monocarboxyiic alkanoic adds (C5 means five carbon atoms, Cη means seven carbon atoms and Cq means -nine carbon atoms), the C5 add being a straight or branched chain add and comprising about 0-50 wt. of the add mixture, such as 30- 50 wt. %. the Cη add bang straight or branched chain, preferably an -S0-C7 add having only one or two methyl branches and comprising about 40-92 wt. % of the add mixture, and the Cq add bang 3,5,5-trimethyihexanoic add and comprising about 8- 12 wt. % of the add mixture. The pentaerythritol alkanoic add esters useful in accordance with this invention are made by completely esterifying pentaerythritol, using methods well known to those skilled in the an. with the mixture of C5, Cη, and Cq monocarboxyiic alkanoic adds. Pentaerythritol used in accordance with this invention is monopentaerythritol or a mixture of at least 70% by wάght monopentaerythritol and one or more poiyperaaerythritois. such as for example, technical pentaerythritol, which is a mixture of monopentaerythritol and about 12% by wdght poiypeπtaerythritois, mostly dipentaerythritol. Preferably stabilizers, such as for example lead phthalate, are also added dining piasticizing to prevent dehydrochlorination and oxidation of the PVC during processing and later use. Other useful additives are known and include, for example, pigments, fillers, and lubricants (i.e., processing aids), which uses depend on the specific PVC application and will be apparent to those skilled in the an. The term "poiyvinyi chloride" as used herein is intended to cover those homo- and copoiymer resins of vinyl chloride known to persons of ordinary skill in the an. Generally speaking, copoiymers of vinyl chloride (containing up to about 20% of such monomers as vinyl acetate, propyiene. ethylene. diethyi maieate, dimethyl fumarate, and other ethvlenicaiiv unsaturated monomers) are intended to be covered. The compositions of the plasticized poiyvinyi chloride resins of the present invention may be formulated, in addition to the above described piasticizers, with various kinds of additives according to need. For example, additives which contribute to improvement of properties such as heat stability, lubridty, weathering resistance and the like, are exemplified by metal soaps such as caldum stearate, zinc stearate, lead stearate, barium stearate. cadmium stearate and the like, tribasic lead sulfate, dibasic lead phosphite, organotin compounds such as dibutyitin dilaurate, dibutyitin dimaleate, di-n-octy in mercaptide. dimethyltin mercaptide and the like as a stabilizer, and esters such as butyl stearate. aliphatic add amides such as ethylene bistearamide, higher fatty adds such as stearic acid and polyethylene waxes as a lubricant, fillers, anti-oxidams, ultraviolet absorbers, anti-static agents, aπti-fogging agent, pigments, dyestufiEs, crossiinking aids and the like. As stabilizers there can be dted, for example, metal soaps (e.g., potassium stearate, zinc stearate. aluminum stearate and the like), inorganic add salts (e.g., dibasic phosphorous acid salt, dibasic sulfuric add salt and the like), and organic metal compounds (e.g., dibutyitin maieate, dioctyitin maieate, dioctyitin bis(2-ethylhexyl maleate) and the like as organic tin stabilizer, epoxyiated soybean oil, or epoxy resin and the like). As fillers there can be dted, for example, inorganic fillers (e.g., hydrate silica, caldum carbonate, talc, diatomaceous earth, kaolin clay, sedimented barium sulfate and the like), and organic alloying polymers such as thermoplastic resins (e.g., cellulose-, polyethylene terephthaiate-. acrylic rubber- and urethane-based resins). The lubricant includes various kinds of paraffins and waxes, fatty add amides, fatty add esters, fluorohydrocarbons, organic siiicones, as well as metal soaps. The pigment may be of any type as far as it is suited for coloring. There can be used various pigments such as inorganic pigments (e.g., titanium oxide and red oxide) and organic pigments (e.g., carbon black, phthalocyanin blue singly or in the form of a mixture). ■ 4 - EXAMPLES Pentaerythriioi esters were prepared from a mixture composed of 50 wt. % n- Cs acid, 40 wt o-Cη acid. 10 wt. % 3,5,5-trimethylhexanoic add (ESTER A), 38 wt. % n-C ξ aαd. 54 w % iso-Cη add. and 8 wt. % 3,5,5-trimethylhexanoic add (ESTER B). Both ESTER A and ESTER B were compatible over the range of 20-70 phr when compounded with PVC. These esters were evaluated for smoke generation in flexible PVC in accordance with ASTM E-662, which compares the smoke generation with a standard plasticizcr. diisodecvi phthaiate (DIDP), and ESTER A and ESTER B exhibited an average smoke reduction of 12-24% as reported below in Table 1. "DS g" means density of smoke per gram. TABLE 1

Claims: CLAIMS : 1. A plasticized poiyvinyl chloride composition exhibiting heat resistant and low smoke generating propeπies wherein the piastidzer consists essentially of a pentaerythritol ester of a mixture of about 0-50 wt. % of C5 alkyl carboxylic add, 40- 92 wt. % of C7 alkyl carboxylic acid, and 8-12 wt. % of 3,5,5-trimethyihexanoic add and is present in an amount equal to 20-70 pans per hundred pans of resin. 2. The composition of claim 1 wherein the C5 and C7 adds are methyl branched chain acids 3. The composition of claim 1 wherein the C5 add is present in an amount of about 38%, the C7 acid is present in an amount of about 54%, and the 3,5.5-trimethylhexanoic acid is present in an amount of about 8%. 4. The composition of claim 1 wherein the C5 add is present in an amount of about 50%. the C7 acid is present in an amount of about 40%, and the 3,5,5-trimethyihexanoic acid is present in an amount of about 8%. 5. The composition of claims 1, 2, 3 or 4 wherein the piastidzer is present in an amount of 50-70 pans per hundred pans of resin.

Inventors: BENITEZ FRANCISCO MANUEL, GERALD JAMES DARRELL, HOOTON JOHN ROBERT, KRAUSKOPF LEONARD GORDON, SCHLOSBERG RICHARD HENRY, BENITEZ, FRANCISCO, MANUEL, GERALD, JAMES, DARRELL, HOOTON, JOHN, ROBERT, KRAUSKOPF, LEONARD, GORDON, SCHLOSBERG, RICHARD, HENRY
Applicants: EXXON CHEMICAL PATENTS INC, EXXON CHEMICAL PATENTS INC.
Application year: 1995
Main classification: C08K5
IPC codes: C07C69, C08K5