The present invention relates to a composition comprising (a) chlorinated polyvinyl chloride and (b) at least one ester of polyglycerol with at least one fatty acid and a process for producing said composition. The invention further relates to a use of said ester as lubricant and/or mold release agent for chlorinated polyvinyl chloride.

BACKGROUND OF THE INVENTION

Chlorinated polyvinyl chloride (abbreviated in the following as CPVC or PVCC) is a polymer often used in pipes for industrial and commercial structures because of its retained strength in the presence of high heat temperatures of solids and fluids travelling through such pipe. For instance, the pipes are used for the transportation of hot water. Nowadays there are PVCC pipes on the market which have only limited food contact approval and are not allowed in US and Europe.

PVCC can be produced by chlorination of polyvinyl chloride (PVC) in a fluidized bed, dispersion or solution process. PVCC has a higher heat resistance compared to PVC and is also more resistant against chemicals. Typical formulations for processing of PVCC are disclosed in EP 0 743 339. The processing of PVCC is more difficult compared to PVC-U (unplasticized polyvinyl chloride) and it is of particular importance which lubricants are used, since the material is more rapidly damaged and the thermal residual stability is reduced.

EP 0 743 339 discloses complex ester in addition to other lubricants in order to process PVCC. Fatty acid complex esters are also disclosed in Plastics Additives Handbook, 5th Edition, (Hanser Verlag, 2001, page 538). JP 5680464 B2 discloses the usage of polyglycerol ester for improving the plate-out of PVC-U.

Thus, especially based on the above identified disadvantages, there is a general need in the art for lubricants and/or mold release agents which can be used in order to improve the processing of PVCC and to get food contact approval. SUMMARY OF THE INVENTION

The present invention provides in an aspect a composition comprising

(a) chlorinated polyvinyl chloride and

(b) at least one ester of polyglycerol with at least one fatty acid, wherein

i. the polyglycerol has a degree of polymerization ranging from 2 to 10, preferably 3 to 6, and

ii. the at least one ester has a degree of esterification ranging from 1 to 12, preferably 3 to 8, and

iii. wherein the at least one fatty acid has a carbon chain ranging from C12 to C30, preferably C14 to C24.

As shown in the examples, the esters of the invention improve the processability of PVCC. Especially the combination with paraffins allows a gentle processing of PVCC according to which a slower plasticization and a prolongation of the thermal stability are obtained.

In a further aspect of the present invention the use of at least one ester of polyglycerol with at least one fatty acid is provided. In a further aspect the process for producing the composition of the present invention is provided.

DETAILED DESCRIPTION OF THE INVENTION

Before the present invention is described in detail below, it is to be understood that this invention is not limited to the particular methodology, protocols and reagents described herein as these may vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present invention which will be limited only by the appended claims. Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art. In the following passages different aspects of the invention are defined in more detail. Each aspect so defined may be combined with any other aspect or aspects unless clearly indicated to the contrary. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features indicated as being preferred or advantageous. Nothing herein is to be construed as an admission that the invention is not entitled to antedate such disclosure by virtue of prior invention.

The present invention relates to a composition comprising

(a) chlorinated polyvinyl chloride and

(b) at least one ester of polyglycerol with at least one fatty acid, wherein

i. the polyglycerol has a degree of polymerization ranging from 2 to 10, preferably 3 to 6,

ii. the ester has a degree of esterification ranging from 1 to 12, preferably 3 to 8, iii. wherein the at least one fatty acid has a carbon chain ranging from C12 to C30, preferably C14 to C24.

In context with the present invention“chlorinated polyvinyl chloride” is a polyvinyl chloride produced by chlorination of polyvinyl chloride (PVC), preferably via a free radical chlorination reaction. The chlorinated polyvinyl chloride comprises preferably the repeating units [CHC1-CHC1] and [CH ₂ -CHCl] This chlorination reaction is typically initiated by application of thermal or UV energy.

In the chlorination process, chlorine gas is preferably decomposed into free radical chlorine which is then reacted with PVC, wherein essentially a portion of the hydrogen is replaced with chlorine in the PVC.

Depending on the method, a varying amount of chlorine can be introduced into the PVC polymer. The chlorine content may vary and can be from 56 % to 74% by mass, preferably 60% to 70% by mass, preferably 63% to 69% by mass (based on the total mass of the PVCC). As the chlorine content in CPVC is increased, compared to PVC, e.g. its glass transition temperature (Tg) increases significantly, compared to PVC. In context with the present invention “polyvinylidene chloride” (PVDC) is a homopolymer of vinylidene chloride and is composed of the repeating units [CH2-CCI2].

In context with the present invention“chlorinated polyethylene” (CPE) is produced by the chlorination of polyethylene and has preferably a chlorine content of 25 to 35 % by weight, preferably 28 to 33% by weight.

In context with the present invention the term“ester of polyglycerol with at least one fatty acid” means that at least one ester group is present which is formed between one hydroxyl group of the polyglycerol and one carboxylic group of a fatty acid. The maximum degree of esterification can be expressed by the degree of polymerization of polyglycerol plus 2. For instance, in case of triglycerol (degree of polymerisation = 3) the maximum degree of esterification is 5 (= 3 + 2).

In context with the present invention“degree of polymerization of polyglycerol” means the number of glycerols present in the polyglycerol. For instance, diglycerol has a degree of polymerisation of 2. In order to produce polyglycerol glycerol is preferably heated to above 200 °C in the presence of an alkaline catalyst.

In context with the present invention the term“paraffin wax” is commonly known in the art and is to be understood as white or colourless soft solid derivable from petroleum, coal or oil shale, that comprises, preferably consists of, a mixture of hydrocarbon molecules containing between 20 and 40 carbon atoms. It is preferably solid at room temperature and begins preferably to melt above approximately 37 °C (99 °F). Its boiling point is preferably above 370 °C (698 °F).

The feedstock for paraffin is preferably slack wax, which is a mixture of oil and wax, a by-product from the refining of lubricating oil. The first step in making paraffin wax is preferably to remove the oil (de-oiling or de -waxing) from the slack wax. The oil is preferably separated through crystallization. Most commonly, the slack wax is preferably heated, mixed with one or more solvents such as a ketone and then cooled. As it cools wax crystallizes out of the solution, leaving only oil in the solution. This mixture is preferably filtered into two streams: solid (wax plus some solvent) and liquid (oil and solvent). After the solvent is preferably recovered by distillation, the resulting products are called "product wax" (or "press wax") and "foots oil". In context with the present invention the term “oxidized polyethylene wax” is commonly known in the art and the oxidized polyethylene wax can be produced by the oxidation of polyethylene. Preferably, oxidized polyethylene waxes are prepared by oxidizing polyethylene waxes with oxygen or oxygen-containing gases, e.g. ozone, at from 120 to 250 °C under a pressure of from 1 to 200 bar.

Preferably, the composition of the present invention comprises at least one ester having the formula I

Formula I wherein R is independently selected from the group consisting of H and fatty acid moieties, wherein at least one R is a fatty acid moiety, and n ranges from 2 to 10, preferably 3 to 6.

Preferably, the composition of the present invention comprises a mixture of esters, wherein the mixture of esters is formed by reacting a mixture of polyglycerols and at least one fatty acid. Preferably, the mixture of esters is produced by reacting a mixture of polyglycerols with one, two or more fatty acids.

Preferably, the mixture of polyglycerols comprises triglycerol and tetraglycerol. Preferably, the mixture of polyglycerols comprises diglycerol, triglycerol, tetraglycerol and pentaglycerol.

Preferably, the mixture of polyglycerols has a content of diglycerol of at least 30%, preferably at least 35%, preferably at least 40%, preferably at least 50%, preferably at least 60%, preferably at least 70% (based on the total molar amount of polyglycerols). Preferably, the mixture of polyglycerols has a content of diglycerol of 30 to 60%, preferably 40 to 50% (based on the total molar amount of polyglycerols). Preferably, the mixture of polyglycerols has a content of triglycerol of at least 15%, preferably at least 20%, preferably at least 30%, preferably at least 40%, preferably at least 50%, preferably at least 55%, preferably at least 60%, preferably at least 65%, preferably at least 70% (based on the total molar amount of poly glycerols). Preferably, the mixture of polyglycerols has a content of triglycerol of 10 to 40%, preferably 20 to 30% (based on the total molar amount of polyglycerols).

Preferably, the mixture of polyglycerols has a content of tetraglycerol of at least 10%, preferably at least 20%, preferably at least 30%, preferably at least 35%, preferably at least 40%, preferably at least 45%, preferably at least 50% (based on the total molar amount of polyglycerols). Preferably, the mixture of polyglycerols has a content of tetraglycerol of 5 to 20%, preferably 10 to 15% (based on the total molar amount of polyglycerols).

Preferably, the mixture of polyglycerols has a content of pentaglycerol of at least 5%, preferably at least 10 %, preferably at least 15%, preferably at least 20%, preferably at least 25% (based on the total molar amount of polyglycerols). Preferably, the mixture of polyglycerols has a content of pentaglycerol of 1 to 15%, preferably 5 to 10% (based on the total molar amount of polyglycerols).

Preferably, the mixture of polyglycerols has a content of diglycerol of 30 to 60%, preferably 40 to 50%, tri glycerol of 10 to 40%, preferably 20 to 30%, tetraglycerol of 5 to 20%, preferably 10 to 15%, and pentaglycerol of 1 to 15%, preferably 5 to 10% (each based on the total molar amount of polyglycerols).

Preferably, the degree of esterification is at least 55%, preferably at least 60%, preferably at least 70%, preferably at least 80%, preferably at least 90%, preferably at least 95%, preferably at least 99% (based on the total amount of hydroxyl groups present in the polyglycerol or in the mixture of polyglycerols). Preferably, the degree of esterification of polyglycerols with a degree of polymerization of 2 to 10, preferably 3 to 6, is at least 90%, preferably at least 95%, preferably at least 99% (based on the total amount of hydroxyl groups present in the polyglycerol or in the mixture of polyglycerols). Preferably, the composition is free of chlorinated polyethylene and/or polyvinylidene chloride.

In a preferred embodiment the present invention relates to a composition, wherein the chlorinated polyvinyl chloride has a chlorine content of 60 to 70 % by weight, based on the total weight of the chlorinated polyvinyl chloride (a), and/or a density of 1.5 to 1.6 g/cm ³ .

In a preferred embodiment the present invention relates to a composition, wherein the content of polyglycerol is from 5 to 30 % by weight, preferably from 10 to 20 % by weight, based on the total weight of the at least one ester (b).

Preferably, the at least one ester or the mixture of esters has an acid value of at most 10, preferably at most 5, preferably 1.0 to 1.5, preferably 1.1 to 1.2 (mg KOH/g) measured according to DIN EN ISO 2114.

Preferably, the at least one ester or the mixture of esters has a hydroxyl value of 10 to 30, preferably of 12 to 18 (mg KOH/g) measured according to DIN 53240.

Preferably, the at least one ester or the mixture of esters has a dropping point of preferably 50°C to 60°C, preferably 50 to 55°C, preferably 55°C to 60°C measured according to DIN ISO 2176.

In a preferred embodiment the present invention relates to a composition, wherein the at least one fatty acid has a straight or a branched chain.

In a preferred embodiment the present invention relates to a composition, wherein the at least one fatty acid is a saturated or unsaturated fatty acid. Saturated fatty acids are preferred.

In a preferred embodiment the present invention relates to a composition, wherein the at least one fatty acid is a naturally occurring or artificially produced.

In a preferred embodiment the present invention relates to a composition, wherein the at least one saturated fatty acid is selected from the group consisting of lauric acid (C12), tridecylic acid (C13), myristic acid (Cl 4), pentadecylic acid (C15), palmitic acid (C16), margaric acid (Cl 7), stearic acid (Cl 8), nonadecylic acid (Cl 9), arachidic acid (C20), heneicosylic acid (C21), behenic acid (C22), tricosylic acid (C23), lignoceric acid (C24), pentacosylic acid (C25), cerotic acid (C26), heptacosylic acid (C27), montanic acid (C28), nonacosylic acid (C29), melissic acid (C30) and any mixture thereof.

Preferably, the at least one saturated fatty acid is selected from the group consisting of myristic acid (Cl 4), pentadecylic acid (Cl 5), palmitic acid (Cl 6), margaric acid (Cl 7), stearic acid (Cl 8), nonadecylic acid (Cl 9), arachidic acid (C20), heneicosylic acid (C21), behenic acid (C22), tricosylic acid (C23), lignoceric acid (C24), pentacosylic acid (C25), cerotic acid (C26) and any mixture thereof Preferably, the at least one saturated fatty acid is selected from the group consisting of lauric acid (Cl 2), myristic acid (C14), palmitic acid (Cl 6), stearic acid (Cl 8), behenic acid (C22) and any mixture thereof In a preferred embodiment the present invention relates to a composition, wherein the at least one unsaturated fatty acid is selected from the group consisting of myristoleic acid (C14, cis-9), palmitoleic acid (Cl 6, cis-9), sapienic acid (Cl 6, cis-9), oleic acid (Cl 8, cis-9), elaidic acid (C18, trans-9), vaccenic acid (C18, cis-l l), gadoleic acid (C20, cis-9), eicosenoic acid (C20, cis-l l), erucic acid (C22, cis-l3), nervonic acid (C24, cis- 15), linoleic acid (C18, cis-9, cis-l2), eicosadienoic acid (C20, cis-l l, cis-l4), docosadienoic acid (C22, cis-l3, cis-l6), a- linolenic acid (Cl 8, cis-9, cis- 12, cis- 15), g-linolenic acid (Cl 8, cis-6, cis-9, cis- 12), pinolenic acid (C18, cis-5, cis-9, cis-l2), a-eleostearic acid (C18, trans-9, trans-l l, cis-l3), b- eleostearic acid (C18, trans-9, trans-l l, trans-l3), mead acid (C20, cis-5, cis-8, cis-l l), dihomo-y-linolenic acid (C20, cis-8, cis-l l, cis-l4), eicosatrienoic acid (C20, cis-l l, cis-l4, cis- 17), stearidonic acid (Cl 8, cis-6, cis-9, cis- 12, cis- 15), arachidonic acid (Cl 8, cis-5, cis-8, cis-l l, cis-l4), eicosatetraenoic acid (C20, cis-8, cis-l l, cis-l4, cis-l7), adrenic acid (C22, cis-7, cis-lO, cis-l3, cis-l6), bosseopentaenoic acid (C18, cis-5, cis-8, trans-lO, trans-l2, cis- 14), eicosapentaenoic acid (C20, cis-5, cis-8, cis-l l, cis-l4, cis-l7), ozubondo acid (C22, cis- 4, cis-7, cis-lO, cis-l3, cis-l6), sardine acid (C22, cis-7, cis-lO, cis-l 3, cis-l6, cis-l9), tetracosanolpentaenoic acid (C24, cis-9, cis-l2, cis- 15, cis-l 8, cis-2l), docosahexaenoic acid (C22, cis-4, cis-7, cis-lO, cis-l3, cis-l6, cis-l9), herring acid (C24, cis-6, cis-9, cis-l2, cis-l5, cis- 18, cis-2l) and any mixture thereof

Preferably, a mixture of at least two, preferably of exactly two fatty acids is present in the at least one ester of the present invention. Preferably, the ester comprises a mixture of stearic acid and at least one further fatty acid, preferably selected from the group consisting of palmitic acid, lauric acid, myristic acid, behenic acid and a mixture thereof. Preferably, a mixture of at least one saturated fatty acid and at least one unsaturated fatty acid is present in the at least one ester.

In a preferred embodiment the present invention relates to a composition, which further comprises paraffin wax. In a preferred embodiment the present invention relates to a composition, which further comprises polyethylene and/or, preferably oxidized, polyethylene wax.

In a preferred embodiment the present invention relates to a composition, wherein the at least one ester (b) is present in an amount ranging from 0.10 to 10 parts, 0.5 to 6, preferably 1 to 6 parts, preferably 0.6 to 1.9, parts per hundred parts of the chlorinated polyvinyl chloride. In a preferred embodiment the present invention relates to a composition, which is present in form of a dry blend or in co-extruded form.

The present invention also relates to use of at least one ester of polyglycerol with at least one fatty acid, wherein i. the polyglycerol has a degree of polymerization ranging from 2 to 10, preferably 3 to 6,

ii. the at least one ester has a degree of esterification ranging from 1 to 12, preferably 3 to 8, and

iii. the at least one fatty acid has a carbon chain ranging from C12 to C30,

preferably C14 to C24,

as lubricant and/or mold release agent for chlorinated polyvinyl chloride.

A“mold release agent” is a chemical used to prevent other materials from bonding to surfaces. Mold release agent preferably provides a critical barrier between a molding surface and the PVCC, facilitating separation of the cured part from the mold. Without such a barrier in place the substrate can become fused to the mold surface, resulting in difficult clean-up and dramatic loss in production efficiency.

In contrast thereto,“plate-out” is an extrusion phenomenon that causes formulators and processors significant problems when processing PVC or PVCC. It is an unwanted deposit that is formed on different sections of extrusion equipment that can cause unacceptable streaking and scoring on the final product through continued deposition. Thus, plate out is an uncontrolled formation of frequently troublesome deposits or coatings on hot or cold metal surfaces in a processing line of PVC or PVCC.

Preferably, the at least one ester or the mixture of esters is used for reducing and/or avoiding plate-out during the processing of PVCC.

Preferably, a composition according to the present invention or according to one or more preferred embodiments is used as lubricant for chlorinated polyvinyl chloride and/or in a composition comprising chlorinated polyvinyl chloride and/or mold release agent in the processing of chlorinated polyvinyl chloride. The present invention also relates to a process for producing a composition, preferably according to the present invention or to one or more preferred embodiments, wherein the process comprises the following process steps:

(a) providing chlorinated polyvinyl chloride and at least one ester of polyglycerol with at least one fatty acid, wherein

i. the polyglycerol has a degree of polymerization ranging from 2 to 10, preferably 3 to 6,

ii. the at least one ester has a degree of esterification ranging from 1 to 12, preferably 3 to 8, and

iii. the at least one fatty acid has a carbon chain ranging from C12 to C30,

preferably C14 to C24;

(b) mixing the chlorinated polyvinyl chloride and the at least one ester provided in step (a); and

(c) obtaining the composition.

In a preferred embodiment the present invention relates to a process, wherein in step (b) least one of paraffin wax, polyethylene and, preferably oxidized, polyethylene wax is added. Preferably, paraffin wax and oxidized polyethylene wax is added in step (b).

Preferably, the mixing of step (b) is obtained by (co-)extruding the chlorinated polyvinyl chloride and the at least one ester provided in step (a), preferably together with least one of paraffin wax, polyethylene and, preferably oxidized, polyethylene wax. Preferably, the process is carried out in order to obtain the composition according to the present invention or according to one or more preferred embodiments.

Various modifications and variations of the invention will be apparent to those skilled in the art without departing from the scope of the invention. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments.

The following examples are merely illustrative of the present invention and should not be construed to limit the scope of the invention as indicated by the appended claims in any way.

EXAMPLES

Example 1 : Production of polyglycerol

Polyglycerol was produced according to the process disclosed in EP 0 151 755, wherein 1 % by weight sodium hydroxide and no hypophosphorous acid was used as catalyst. The product had a hydroxyl value of 1046, a refractive index (20°C) of 1.4965 and a content of free glycerine of 6.9%.

Example 2: Production of polyglyceryl stearate Polyglyceryl stearate was produced according to the process disclosed in EP 2 666 813. The polyglycerol of example 1 and stearic acid (EDENOR ST 1) from the company KLK were deployed. The produced polyglyceryl ester had the following properties:

Acid value: 1.13 (mg KOH/g) DIN EN ISO 2114

Saponification value: 182 (mg KOH/g) DIN EN ISO 3681 Hydroxyl value: 15 (mg KOH/g) DIN 53240

Dropping point: 52.3 (°C) DIN ISO 2176

Examples 3 to 5: Production of dryblends

A dryblend was produced made of a PVCC powder and the components listed in the table 1, below by using a mixer of the company Vorwerk. 400g of the components were mixed at a temperature of l00°C. Subsequently, the mixture was cooled to room temperature. The compositions were as shown in Table 1:

The unit is phr (= per hundred resin) used in tables 1, 3 and 5 below. Table 1

The produced dryblends were plasticized in a torque rheometer (measuring mixer) of the company Brabender (Plasti-Corder Lab-Station W 50 EHT) at a temperature of l80°C and a rotational speed of 30 rpm. The weigh-in was 50g and the torque over the time was measured. The mixtures were remained in the mixer for 10 minutes. The time until the maximal torque is reached is also designated as plasticizing time. B3 is a comparative example with a complex ester. The compositions B4 and B5 are according to the present invention. The thermal stability of the kneaded materials was determined according to the Congo red method (EN 60811) at 200°C. Table 2

The polymer formulations were plasticized in a slower and more gentle way, when the lubricants according to the present invention were used, which results to a lower damage of the material and consequently to the longer thermal stability (see table 2, above). Examples 6 to 8: Production of dryblends (+ paraffin)

Dryblends were produced from the components as listed in table 3, below. The dryblends were extruded to flat-bands by a conic twin screw extruder of the company Brabender. The temperature profde was Z1/Z2/Z3/AD/D (zone 1 / zone 2 / zone 3 / adapter / die) = 160/170/180/180/180°C and the rotational speed of 50 rpm.

Table 3

The pressure in the extruder nozzle was determined: Table 4

The combination of paraffin and polyglyceryl ester allows a more gentle processing (lower pressure) compared to the sole usage of paraffin or polyglyceryl ester (table 4, above).

Examples 9 and 10: Production of dryblends (+ paraffin + oxidized PE wax)

The dryblends were produced and plasticized in a torque rheometer (measuring mixer) of the company Brabender (Plasti-Corder Lab-Station W 50 EHT) at a temperature of l80°C and a rotational speed of 30 rpm. The compositions were as shown in table 5:

Table 5

The thermal stability of the kneaded materials was determined according to the Congo red method (EN 60811) at 200°C.

Table 6

The combination of paraffin, oxidized PE wax and polyglyceryl ester allows an even more gentle processing (lower pressure) and longer thermal stability compared to the usage of paraffin and polyglyceryl ester (table 6, above).