MXPA06010042A - Aliphatic ester compounds as slip agents in polyester polymers - Google Patents

Abstract

Use of a compound of general formula (1) as a slip agent in a PET polymer, wherein:R and R1 represent hydrocarbon moieties, each hydrocarbon moiety comprising 6 to 24 carbon atoms and wherein R and/or R1 may be linear, branched chain, saturated or contain one or more double a bonds;X represents one of the moieties (a), wherein A represents a hydrocarbon moiety comprising 2 to 36 carbon atoms and may be linear, branched chain, saturated or contain one or more double bonds.

Description

ALIPHATIC ESTER COMPOUNDS AS SLIDING AGENTS IN POLYESTER POLYMERS FIELD OF THE INVENTION The present invention relates to polymer additives, it is particularly applicable to additives that reduce the coefficient of friction in a polyester polymer such as PET.

BACKGROUND OF THE INVENTION Poly (ethylene terephthalate) (PET) is an important plastic material, widely used in the manufacture of molded polyester articles and films. The key advantages of using PET are: High clarity Light weight Good processability Excellent barrier properties against oxygen and carbon dioxide Good impact resistance Strong-virtually non-breaking Economic. By far as a result of the above properties, the most important application of plastic for PET homopolymers and copolymers is the manufacture of bottles. PET bottles are produced predominantly using a blow molding process with double voltage stage. First, a preform is produced by injection molding. This is a relatively thick wall part with the characteristics of the neck molded during this process. The preform is then reheated in an overheated blow machine that stresses the preform into a tension pin and inflates it by blowing air into the mold to give it the desired shape. This gives a biaxially oriented vessel that provides improved properties such as clarity and gas barrier performance. This is especially important for containers with carbonated drinks. PET bottles can also be made by injection blow molding, which is a two-stage technique developed on a simple machine. The preform is molded by injection and while it is still hot it is moved to a blowing station where it is blown to achieve the desired shape. This is the preferred technique for small containers that require a specific neck or terminal detail and produce containers that are less biaxially oriented. A major difficulty in manufacturing PET articles is the relatively high coefficient of friction of the polymer. In bottle making this problem can manifest itself in a number of ways: Less than optimum packing density when preforms repackaged in a box with the attendant high storage and transportation costs. • Poor flow over the transport equipment and thus reduced flow. Defects in surface due to poor resistance to peeling. There is thus a need for an effective additive system for PET that reduces the coefficient of friction of the polymer and thus solutions the previous deficiencies. Additives that are effective in reducing the coefficient of friction of polymers are known in the industry as slip additives. However, in order to be acceptable for beverage containers, the manufactured PET bottle must exhibit low color and high clarity, with low taste and odor and not be toxic. This imposes other important requirements on the slip agent in addition to its properties of reducing friction. Conventional slip agents of choice in the plastics industry are fatty amides. These additives are widely used in polyolefins such as polyethylene, polypropylene, and related copolymers. Fatty amides used with slip additives are generally made from fatty acids containing between 16 and 22 carbon atoms and are characterized by a variety of structural forms: Primary amides which may be monounsaturated (as exemplified by erucamide and oleamide) or saturated (as exemplified by stearamide and behenamide). The secondary amides exemplified by stearyl erucamide and oleyl palmitamide. Bis amides such as ethylene bis stearamide. In view of its wide use in polymer systems, it might seem logical to consider fatty amides as slip agents for polyesters such as PET. However, we have established that before the fatty amides do not show some friction reduction properties in the PET, the decrease in the coefficient of friction is much less than in the polyolefins. Moreover, all amides cause discoloration in injection molded PET that will severely restrict its usefulness in this polymer. Those skilled in the art will be aware that separate and different classes of polymers have widely different chemical compositions and different molecular architectures. Thus, polyester polymers such as PET can not be compared with polyvinyl chloride (PVC), polyamides such as nylon, or other kinds of polymers. Not only do they behave differently as polymers, but different slip agents are required with different kinds of polymer. That is, one can not extrapolate or predict how a particular compound or mixture of compounds will behave as slip agents in an agent based on its performance as a slip agent in a different class of polymers. The technology of conventional slip agents can not therefore be easily applied in PET. This is particularly the case of bottle making (preform) where the addition of a low coefficient of friction, other strict requirements regarding color, taste and odor must be met.

OBJECTS AND BRIEF DESCRIPTION OF THE INVENTION It is therefore an object of the present invention to provide compositions that have improved slip and bimetability characteristics when using polymers such as PET and where other polymer properties are not adversely affected. According to a first aspect of the present invention, the use of a compound of general formula 1 as a slip agent in a polyester polymer is provided. R-X-R1 (1) Where. R and R1 represent hydrocarbon portions, each hydrocarbon portion comprises 1 to 34 carbon atoms and wherein R and / or R can be a straight, branched, saturated chain or contain one or more double bonds; and where X represents one of the portions O Jl -C-O- o o fí II -O- C-A- C - Q- O O H Jt -C-O-A O-C - wherein A represents a hydrocarbon portion comprising 2 to 36 carbon atoms and can be straight chain, branched, saturated or contain one or more double bonds. Preferably the total number of carbon atoms R, R1 and X is greater than 16 and more preferably greater than 22. In a particularly preferred embodiment the total number of carbon atoms in R, R1 and X is greater than 35. Preferably X represents Serving and the total number of carbon atoms in R, R1 and X is between 23 and 44. In a particularly preferred embodiment the composition of general formula 1 is selected from the group comprising stearyl stearate, stearyl behenate, behenyl behenate, ethylene glycol distearate , ethyl behenate, behenyl acetate, palmityl myristate, palmityl palmate or mixtures of these. In a particularly preferred embodiment, the polyester polymer is selected from the group consisting of: Poly (butylene terephthalates) Poly (cyclohexanedimethylene terephthalate) Poly (ethylene isophthalate) Poly (ethylene 2,6-naphthalene dicarboxylate) Poly (ethylene phthalate) Poly (ethylene terephthalate) Preferably said composition of general formula 1 is present in said polymer in an amount between 0.1% to 1.0% w / w. In a particularly preferred embodiment said composition is present in said polymer in an amount between 0.2% to 0.75% w / w. According to a second aspect of the invention, a polyester polymer is provided that incorporates one or more slip agents in general formula 1: RX-R1 0) Where: R and R1 represent hydrocarbon portions, each hydrocarbon portion comprises 1 to 34 carbon atoms and wherein R and / or R1 may be a straight, branched, saturated chain or contain 1 or more doubles links; and where X represents one of the portions: OR II OO (I II -O- CA- C -O- oo li II -C-OAO-C- wherein A represents a hydrocarbon portion comprising 2 to 36 carbon atoms and can be a straight, branched, saturated or contain one or more double bonds Preferably the total number of carbon atoms in R, R1 and X is greater than 16 and more preferably greater than 22. In a particularly preferred embodiment the total number of carbon atoms in R, R1 and X is greater than 35. Preferably X represents the portion and the total number of carbon atoms in R, R1 and X is between 23 and 44. In a particularly preferred embodiment the slip agent of general formula 1 is selected from the group comprising stearyl stearate, stearyl behenate, behenyl behenate, ethylene glycol distearate, ethyl behenate, behenyl acetate, palmityl myristate, palmityl palmate or mixtures of these. Where the polymer is intended for fiber production the slip agent is preferably not a stearyl ester such as stearyl stearate or other additives especially named in GB2152061 (Snia fiber SpA). The additives referred to in GB2152061 are described in the context of the fibers extracted, not in the context of the slip additive, or in the context of preforms or bottles as in the present application. Preferably said polymer is selected from the group consisting of: Poly (butylene terephthalate) Poly (cyclohexanedimethylene terephthalate) Poly (ethylene softalate) Poly (ethylene 2,6-naphthalene dicarboxylate) Poly (ethylene phthalate) Poly (ethylene terephthalate) And copolymers thereof. Preferably said slip agents are present in said polyester polymer in an amount between 0.1% to 1.0% w / w.

In a particularly preferred embodiment said slip agents (S) are present in said polymer in an amount between 0.2% to 0.75% w / w. According to a third aspect of the present invention there is provided a method for treating the polymer to increase the slippage of said polymer said method comprises incorporating into said polymer a composition of general formula 1 as defined above. Preferably said polymer is selected from the group comprising: Poly (butylene terephthalate) Poly (cyclohexanedimethylene terephthalate) Poly (ethylene isophthalate) Poly (ethylene 2,6-naphthalene dicarboxylate) Poly (ethylene phthalate) Poly (ethylene terephthalate) And copolymers thereof Preferably the said composition of general formula 1 is present in said polymer in an amount of between 0.1% to 0.1% w / w. In a particularly preferred embodiment said composition of general formula 1 is present in said polymer in an amount of between 0.2% to 0.75% w / w. According to further aspects of the present invention, a preform and a container made of a polymer as described herein is provided, which incorporates a slip agent of general formula 1. Preferably said container is formed of a polymer selected from a group that comprises: Poly (butylene terephthalate) Poly (cyclohexanedimethylene terephthalate) Poly (ethylene isophthalate) Poly (ethylene 2,6-naphthalene dicarboxylate) Poly (ethylene phthalate) Poly (ethylene terephthalate) and copolymers thereof According to a further aspect of the present invention a film made of a polyester polymer is provided as described herein incorporating a slip agent of the general formula 1. Preferably said film is formed of a polymer selected from a group comprising: Poly (butylene terephthalate) Poly (cyclohexanedimethylene terephthalate) ) Poly (ethylene isophthalate) Poly (ethylene 2,6-naphthalene dicarboxylate) Poly (ethylene phthala) to) Poly (ethylene terephthalate) And copolymers thereof The present invention is also extended to include a composition comprising a copolymer of a polyester and a compound of general formula 1 wherein: R and R1 represent hydrocarbon portions, each hydrocarbon portion comprises 1 to 34 carbon atoms and / or R 1 can be a straight, branched, saturated chain or contain 1 or more double bonds; X represents one of the portions: o II - C -O - or 0 II II - G-A - -O- 0 or fl ll -C - 0- -A -O - C wherein A represents a hydrocarbon portion comprising 2 to 36 carbon atoms and can be a straight, branched, saturated chain or contain one or more double bonds.

BRIEF DESCRIPTION OF THE DRAWING Figure 1 is a schematic diagram of the test apparatus.

DETAILED DESCRIPTION The present invention therefore relates to the discovery of a novel range of slip additives for polyester polymers such as PET that are highly effective in lowering the coefficient of friction of the manufactured article while maintaining a low color and high clarity. More particularly, the additives conforming to this invention achieve a rapid reduction in the coefficient of friction which is maintained during a long-term storage of the molded part.

This is particularly critical in the production of PET preforms and bottles. The term "PET" as used herein to describe this invention has a broad meaning. This includes all polymeric and copolymeric forms and poly (ethylene terephthalate). The compounds of this invention are also effective slip agents for other polyester polymers and copolymers as exemplified by polybutylene terephthalate and poly (ethylene naphthalate). Thus the term PET should be considered, in this context, as a generic term to include all polymers derived from aromatic diacids including all polymers of terephthalate and their derivatives, both those known as those still to be discovered. The additives of this invention make up the general structure: R - X- R1 where R and R 'are hydrocarbon portions, each comprising 1 to 34 carbon atoms, and can be a straight or branched chain, and can be completely saturated or contain one or more double bonds. X forms one of the following structures: -C (O) O- or -0 (0) CAC- (0) O- or -C (O) -OAO- (O) C- wherein A is a hydrocarbon portion comprising 2 to 36 carbon atoms , and can be linear or branched and be completely saturated or contain one or more double bonds. In a preferred embodiment of the invention the total number of carbon atoms contained within R, R 'and X is greater than 22 and preferably greater than 35. Examples of referred additives which form this invention are stearyl stearate, behenate stearyl, behenyl behenate, ethylene glycol distearate, ethyl behenate, behenyl acetate, palmityl medistate, palmityl palmate or mixtures thereof. In order to achieve and achieve the required level of performance of P ET, the additives of this invention are incorporated at levels between 0.1% and 1% and preferably between 0.2% and 0.75% w / w. The displacement additives of this invention can be incorporated into the polymer by a number of processes well known to those skilled in the art. For example, they can be added directly to the resin by melting doses at the extrusion point, by adding conventional master batch or by incorporation using liquid color systems.

EXAMPLES To demonstrate the effectiveness of the aforementioned additives in reducing the friction of PET surfaces, the following procedure is adopted. A PET co-polymer (IV 0.8) suitable for the manufacture of bottles and other food packaging containers by injection molding, blow molding or a combination of both is used. The PET is dried for 8 hours at 145 ° C and the additive coated directly on the surface of the polymer by a mixing drum while the polymer is still hot. The PET is molded into 100 x 50 x 2 mm plates on a 35 ton insurance injection molding machine using the following conditions: Temperature: All zones at 270 ° C Injection pressure: 85 Bar Shot size: 29.0mm Packing: 20 Bar; 3 seconds Support: 75 Bar; 3 seconds Cooldown 20 seconds Tool temperature: 10 ° C The coefficient of friction (static and kinetic) of the resultant plates are then measured in a Lloyd LRX voltage tester and a 10N load cell in the following time intervals after molding 1 hour, 24 hours, 1 week and 2 weeks. The friction method is adapted from ASTM 1894. The weight of the sled includes the plate that is 1000g and the area of the contact surface between the two plates is 50mm x 50mm (see diagram). The test was run over a distance of 60mm to 150mm / min. Each test is conducted 5 times for each time interval using new plates for each race. A diagram of the test apparatus is shown in Figure 1. Due to the nature of the PET the friction can vary from day to day depending on the process conditions and environment and its hygroscopic nature. The coefficient of friction recorded for the PET if n additives was generally between 0.5 and 1.2. To allow comparisons with respect to the experiments carried out on different days that carried out the white races before and after each series of PET + additives in each day. The results are reported as a percentage of the target as this was observed given an additive that could give a proportionally lower result on the day where low friction is recorded for the target. A number of mixed ester composition additives were also tested and the representative compositions are given in Table II labeled formulations 1-6.

A summary of the additives tested is given below: TABLE 1 Coefficient of friction (% of white) Static Dynamic Example Conc% initial 1 day 7 days Start! 1 day Erucamida 0.5 85 NR 76 78 NR Behenamide 0.5 62 NR 100 71 NR GMS 90 0.5 0 NR 109 0 NR GMB 0.5 0 NR 124 0 NR Dierucato 0.5 89 NR 140 72 NR PEG200 Dieloate 0.5 NR F NR NR F PEG200 Dieloate 0.5 NR F F NR F pentaerythritol Monooleate 0.5 NR F F NR F pentaerythritol Monolaurate 0.5 NR F F NR F PEG400 Monoseaurate 0.5 NR FF NR F sorbitan This time of 0.5 NR NR 124 NR NR Calcium Tetraesterato 0.5 95 NR 86 107 NR pentaerythritol Stearate of 0.5 86 NR 87 70 NR butyl Stearate of 0.5 80 NR 83 62 NR Ethylexyl Palmitate of 0.5 74 NR 85 63 NR lauryl Behenate of 0.5 122 NR 173 80 NR oleyl Behenate of 0.5 98 NR 94 118 NR behenyl Behenate 0.5 55 NR 55 62 NR lauryl Behenate 0.2 60 NR 72 57 NR lauryl Eurocate 0.5 123 NR F 114 F Oleyl EGDS 0.5 92 90 68 86 95 Eftalate 0.5 45 83 82 54 95 Cetosteryl Behenate 0.05 49 83 34 57 64 Butyl Behenate 0.1 33 65 33 52 62 Butyl Behenate 0.2 18 38 24 42 55 Butyl Behenate 0.5 15 30 16 27 33 Butyl Formulation 0.1 64 50 58 91 59 ester 1 Formulation 0.2 38 38 36 45 38 ester 1 Formulation 0.3 29 34 30 32 30 ester 1 Formulation 0.2 69 51 80 62 ester 2 Formulation 0.2 67 54 64 44 ester 3 Stearate 0.1 100 92 77 131 92 stearyl stearate • 0.2 34 41 37 41 39 stearyl stearate 0.3 33 40 33 32 36 stearyl Behenate 0.1 60 70 58 135 122 stearyl Behenate 0.2 33 41 91 43 44 stearyl Behenate 0.3 42 49 53 57 48 stearyl Palmitate from 0.1 175 109 312 270 162 stearyl Palmitate from 0.2 62 49 89 69 54 stearyl Palmitate from 0.3 33 39 30 43 36 stearyl Formulation 0.2 48 46 48 56 48 ester 4 Formulation 0.2 68 57 74 72 55 ester 5 Formulation 0.2 58 46 72 85 63 ester 6 Behenate 0.2 42 49 59 33 42 ethyl Acetate 0.2 34 42 54 31 34 behenyl Succinate 0.2 74 69 68 59 dilauril TABLE 2 Formulation 1 Lauryl alcohol Miristyl palmityl stearyl arachidyl . . , Laurato < 1 < 1 < 1 < 1 < 1 Acid .. ,, Minstato < 1 14-17 8-12 4-6 < 1 Palmitate < 1 32-38 20-24 8-12 < 1 stearate < 1 < 1 < 1 < 1 < 1 Formulation 2 Lauryl alcohol Miristyl palmityl stearyl Arachidyl Laurate < 1 < 1 < 1 < 1 < 1 Myristate acid < 1 13-16 30-34 12-14 < 1 Palmitate < 1 8-10 18-22 7-10 < 1 stearate < 1 < 1 < 1 < 1 < 1 Formulation 3 Alcohol Lauryl Miristyl Palmitoyl Stearyl Arachidyl Laurato < 1 < 1 < 1 < 1 < 1 Myristate acid < 1 < 1 18-22 9-11 < 1 Palmitate '< 1 1.5-1.5 41-45 20-24 < 1 stearate < 1 < 1 < 1 < 1 < 1 -ormulai 3ión 4 Alcohol Laurilo Miristilo palmitilo stearyl araquidilo Laurato < 1 < 1 < 1 < 1 < 1 Myristate acid < 1 7-9 4-6 2-4 < 1 Palmitate < 1 16-19 10-12 5-7 < 1 stearate < 1 < 1 2-4 40-45 < 1 Formulation 5 lauryl myristyl palmityl stearyl alcohol; arachidyl Laurato < 1 < 1 < 1 < 1 < 1 Miristato < 1 14-17 8-12 4-6 < 1 Acid Palmitate < 1 32-38 20-24 8-12 < 1 0 Stearate < 1 < 1 < 1 < 2 < 1 Araquidate < 1 < 1 < 1 1-3 < 1 behenate < 1 < 1 < 1 40-45 < 1 Formulation 6 Alcohol Lauryl myristyl palmityl stearyl arachidyl Laurate < 1 < 1 < 1 < 1 < 1 Myristate acid < 1 7-9 4-6 2-4 < 1 Palmitate < 1 16-19 10-12 48-53 < 1 stearate < 1 < 1 < 1 < 1 < 1 Formulation 1 Lauryl alcohol Miristyl palmityl stearyl arachidyl Laurato < 1 < 1 < 1 < 1 < 1 Acid Miristato < 1 14-17 8-12 4-6 < 1 or Palmitate < 1 32-38 20-24 8-12 < 1 stearate < 1 < 1 < 1 < 1 < 1 Formulation 2 Lauryl alcohol Miristyl palmityl stearyl Arachidyl Laurate < 1 < 1 < 1 < 1 < 1 Acid Miristato < 1 13-16 30-34 12-14 < 1 or Palmitate < 1 8-10 18-22 7-10 < 1 stearate < 1 < 1 < 1 < 1 < 1 Formulation 3 lauryl alcohol Miristyl palmityl stearil araquidyl Laurato < 1 < 1 < 1 < 1 < 1 Myristate acid < 1 < 1 18-22 9-11 < 1 Palmitate < 1 1.5-1.5 41-45 20-24 < 1 stearate < 1 < 1 < 1 < 1 < 1 Formulation 4 Lauryl alcohol Miristyl palmityl stearil araquidyl Laurato < 1 < 1 < 1 < 1 < 1 Acid Miristato < 1 7-9 4-6 2-4 < 1 or Palmitate < 1 16-19 10-12 5-7 < 1 stearate < 1 < 1 2-4 40-45 < 1 Formulation 5 Alcohol lauryl myristyl palmityl stearyl arachidyl Laurate < 1 < 1 < 1 < 1 < 1 Miristato < 1 14-17 8-12 4-6 < 1 Acid Palmitate < 1 32-38 20-24 8-12 < 1 0 Stearate < 1 < 1 < 1 < 2 < 1 Araquidate < 1 < 1 < 1 1-3 < 1 behenate < 1 < 1 < 1 40-45 < 1 Formulation 6 Alcohol lauryl myristyl palmityl stearyl arachidyl Laurato < 1 < 1 < 1 < 1 < 1 Acid Miristato < 1 7-9 4-6 2-4 < 1 or Palmitate < 1 16-19 10-12 48-53 < 1 stearate < 1 < 1 < 1 < 1 < 1 The superior performance of the additives of this invention can be easily appreciated by reference to the above results.

Conventional amide displacement agents, as de-simplified by erucamide (4), reduce the coefficient of friction between 62% and 71% of the target but result in severe yellowing of the polymer. In addition, the effect was short and after 7 days it returns to the control value.

The additives that make up this invention produce an equivalent or greater reduction in the coefficient of friction when compared to conventional displacement amide people but the polymer plates remain clear and transparent. In the examples of stearyl behenate, stearyl palmitate and ester formulation 4, which represents preferred embodiments of this invention, very low coefficients of friction (30% B to 50% of the blank) are achieved at addition levels of only 0.2 to 0.3%. It is to be noted that some polyethylene glycol esters (not conforming to this invention) as illustrated by the PEG 200 dierucate provided an initial reduction in suction coefficient but this defect decreased during the 14 day test period. This produces compounds of this low-value nature and as long-term slip agents for PET. It has been envisioned that slurry mixtures of the general formula 1 can be used in polymers and copolymers and that such agents can also be used in combination with known slip agents. Thus it can be clearly seen that the additives according to the present invention provide the only combination of a fast and durable reduction in the coefficient of friction of PET while maintaining low color and high transparency.

Although it is known that certain compounds of general formula 1 as defined herein have been reported as anti-slip agents in polymers this has not been generally reported in polyester type polymers and in particular not in PET polymers as defined herein. The activity of certain compounds, including, but by no means limited to, the group comprising wasterate stearate, wasate destearyl, venthyl starate, ethelenglycol distearate, ethyl isate, vehenil acetate, palmityl myristate, palmityl palmate or mixtures from them. These groups of compounds provide slip values in the order of 40% or better at the test concentrations when compared to the control. Such values are particularly high and represent a significant improvement over the additives currently used in this context.

PREPARATION 1 materials 85/90% behenic acid, AV = 163.7 MG KOH / G, (MWT 342.7 G / MOL), 200.0 G (0.584 mol). n-butanol (butan-1-ol) 99.4 +% (Aldrich), (mwt 74.12 g / mol), 400.0 g (5.397 mol). Sulfuric acid (98% min) catalyst, 4.0g, or 1% by weight of butanol.

Process A bottle equipped with a stirrer and a vertical water-cooled reflux condenser was charged with the above materials and heated to and maintained at 110-120 ° C under atmospheric pressure at constant reflux of butanol for about 4.5 hours. The resulting mixture was transferred to a separate funnel and then 1 L of n-heptane @ 60 ° C was added followed by 2 L of saturated brine solution. The entire mixture was stirred and the phases allowed to separate. The aqueous phase was removed, and the ethane phase retained. The ethane phase was then repeatedly washed with about 1 L hot distilled water (60 ° C) until the washings gave a pH of 6. The ethane phase was then dried over sodium sulfate in hydrochloride. The filtrate was evaporated to a constant weight on a rotary evaporator @ 70 ° C under 700mmHg of vacuum. Finally, the upper part of the vessel was blown with nitrogen for about 15 minutes to remove traces of butanol odor.

Production 186g (maximum theoretical production = 232.9 g) 80% production.

Analysis of the final product: AV 4.6 mg KOH / g OHV 10.0 mg KOH / g Value Sap 137.3 mg KOH / g Moisture 0.02% by weight Color 156 in haze

Claims (27)

1. Use of a compound of general formula 1 as a slip agent in a polyester polymer: R-X-R1 (1) Wherein: R and R1 represent hydrocarbon portions, each hydrocarbon portion comprises 1 to 34 carbon atoms and wherein R and / or R1 may be a straight, branched, saturated chain or contain one or more double bonds; and where: where X represents: O ii -G-Ü-

2. The use of a component of General Formula 1 as a slip agent in a PET polymer as claimed in claim 1 wherein the total number of carbon atoms in R, R1 and X is greater than 16 and more preferably greater than 22

3. The use of a composition of general formula 1 as a slug agent is claimed in claim 1 or claim 2 wherein the total number of carbon atoms in R, R1 and X is greater than 35.

4. The use of a composition of general formula 1 as a slip agent in a polymer as claimed in any of the preceding claims wherein the total number of carbon atoms in R, R1 and X is between 36 and 44.

5. The use of a composition of general formula 1 as a slip agent in a PET polymer as claimed in any of the preceding claims wherein the composition of general formula 1 is selected from the group comprising stearyl stearate, stearyl behenate, behenate of behenyl, ethylene glycol distearate, ethyl behenate, behenyl acetate, palmityl medistate, palmityl palmate or mixtures thereof. This group of compounds provides sliding values of order of 40% or better in the test concentrations when compared to the target. Such values are particularly high and represent a significant improvement over additives currently used in this context.

6. The use of a general formula 1 composition as a slip agent in a polyester polymer as claimed in claim 6 wherein the PET polymer is selected from the group comprising: Poly (butylene terephthalate) Poly (cyclohexanedimethylene terephthalate) Poly (ethylene isophthalate) Poly (ethylene 2,6-naphthalene dicarboxylate) Poly (ethylene phthalate) Poly (ethylene terephthalate) or copolymers thereof.

7. The use of a composition of general formula 1 as a slip agent in a PET polymer according to any of the preceding claims wherein said composition of general formula 1 is present in said PET polymer in an amount between 0.1% to 1.0 % p / p.

8. The use of a composition of general formula 1 as a slip agent in a PET polymer according to claim 7 wherein said composition is present in said PET polymer in an amount of between 0.2% to 0.75% w / w.

9. The use of a composition of general formula as a slip agent in a PET polymer substantially as given herein.

10. A polyester polymer incorporating one or more slip agents of general formula 1: R-X-R1 (1) Wherein: R and R1 represent hydrocarbon portions, each hydrocarbon portion comprises 1 to 34 carbon atoms and wherein R and / or R1 may be a straight, branched, saturated chain or contain one or more double bonds; and where: where X represents: Or ii -ce-

11. A polymer as claimed in claim 10 incorporating 1 or more slip agents of general formula 1 wherein the total number of carbon atoms in R, R1 and X is greater than 16 and more preferably greater than 22.

12. A polymer as claimed in claim 10 or 11 wherein the total number of carbon atoms in R, R1 and X is greater than 35.

13. A polymer as claimed in any one of claims 10. , 11 o 12 wherein the total number of carbon atoms in R, R1 and X is between 23 and 44.

14. A polymer as claimed in any of claims 10, 11., 12, or 13 which incorporates 1 or more glidants of general formula 1 wherein the composition is selected from the group compng stearyl stearate, stearyl behenate, behenyl behenate, ethylene glycol distearate, ethyl behenate, ethyl acetate, behenyl, paimityl medistate, palmityl palmate or mixtures thereof.

15. A polymer as claimed in any of claims 10 to 14 and wherein said polymer is selected from a group compng: Poly (butylene terephthalate) Poly (cyclohexanedimethylene terephthalate) Poly (ethylene isophthalate) Poly (ethylene 2,6 -naphthalenedicarboxylate) Poly (ethylene phthalate) Poly (ethylene terephthalate) or copolymers thereof.

16. A polymer as claimed in any of claims 10 to 15 and inclusive that incorporates one or more glidants of general formula 1 wherein said glidants are present in said polymer in an amount between 0.1% to 1.0% p / p.

17. A polymer as claimed in claim 16 wherein said slip agents are present in said polymer in an amount between 0.2% to 0.75% w / w.

18. A polymer that incorporates one or more slip agents of general formula 1 substantially as described herein.

19. A method for treating a polyester polymer to increase the slippage of said polymer said method comps incorporating into said polymer a composition of general formula 1 as defined in any of claims 1 to 9 inclusive.

20. A method for treating a polymer as claimed in claim 19 wherein said polymer is selected from a group comprising: Poly (butylene terephthalate) Poly (cyclohexanedimethylene terephthalate) Poly (ethylene softalate) Poly (ethylene 2,6- naphthalenedicarboxylate) Poly (ethylene phthalate) Poly (ethylene terephthalate) or copolymers thereof.

21. A method according to claim 20 wherein said composition of general formula 1 is present in said polymer in an amount between 0.1% to 1.0% w / w.

22. A method according to claim 21 wherein said composition of general formula 1 is present in said polymer in an amount between 0.2% to 0.75% w / w.

23. A container made of a polymer as claimed in any of claims 10 to 18 inclusive.

24. A container as claimed in claim 23 wherein said container is formed from a polymer selected from a group comprising: PoIi (butylene terephthalate) Poly (cyclohexanedimethylene terephthalate) Poly (ethylene isophthalate) Poly (ethylene 2,6 -naphthalenedicarboxylate) Poly (ethylene phthalate) Poly (ethylene terephthalate) or copolymers thereof.

25. A film made of a polymer is claimed in any of claims 10 to 18 inclusive.

26. A film as claimed in claim 25 wherein said film is formed of a polymer selected from a group comprising: Poly (butylene terephthalate) Poly (cyclohexanedimethylene terephthalate) Poly (ethylene isophthalate) Poly (ethylene 2,6-naphthalenedicarboxylate) ) Poly (ethylene phthalate) Poly (ethylene terephthalate) or copolymers thereof.

27. A composition comprising a copolymer of a polyester and a compound of general formula 1 wherein: R and R1 represent parts of hydrocarbons each part of hydrocarbon comprises 1 to 34 carbon atoms and R and / or R1 can be straight or branched, saturated or containing one or more double bonds; and where X represents one or more parts: O JI ~ C-Q ~ or O (1 11 -OCACO- oo fl II -C-0 ~ A-0 ~ G ~ Where A represents a hydrocarbon part comprising 2 to 36 carbon atoms and can be a straight, or branched, saturated or that contains one or more double bonds.