Rubber composition containing additive and use thereof

Abstract

The present invention relates to a rubber composition containing rubber and at least one rubber additive, characterized in that the at least one rubber additive comprises fatty acid esters, which fatty acid ester is produced from at least one C8 to C22 fatty acid and at least one compound selected from C2 to C4 alkoxylate of a polyol, polyethylene glycol, polypropylene glycol and / or copolymer of ethylene oxide and propylene oxide. The present invention further relates to the use of the rubber additive in a rubber composition and to a tire, in which at least one component is at least partially produced from the rubber composition according to the invention, as well as to processes for the production thereof.

Description

Rubber composition containing additive and use thereof Field of the invention The present invention relates to a rubber composition which contains rubber and at least one rubber additive based on a fatty acid ester. Furthermore, the present invention relates to the use of the rubber additive in a rubber composition, and to a tire in which at least one component is made at least partially from the rubber composition according to the invention, as well as to processes for its production. Background of the invention The trend in the development of tread compounds for all-season and winter tires in recent years has been determined by improvements in the properties of tire grip (road adhesion) at low temperatures and tire abrasion (stiffness). In order to achieve this, the respective rubber compositions contain, for example, rubbers with a long chain length.This results in poor processing (high viscosity, lack of green strength) of the rubber compound. In the rubber industry, a variety of processing aids exist, but their use impairs at least one other property, such as lower stiffness (= higher tire wear, poorer handling) or higher rolling resistance. Typically, (cold) plasticizers are added to the rubber formulation for this purpose. This compromise between processing and the performance criteria of tire grip at low temperatures / tire wear and tire rolling resistance is no longer accepted in today's tire compound development, as safety aspects (shorter braking distances at low temperatures) and discussions about particulate matter (tire wear, microplastics) are arguments in favor. are effective marketing and thus significantly influence tire sales. US 2017 / 0051134 A1 relates to a tire rubber composition with improved dispersibility of silica in a rubber and tires made therefrom. The composition comprises a rubber compound and glycerol fatty acid monoesters as well as silica. US 2019 / 0233622 A1 discloses ethoxylated glycerol esterified with fatty acids for use in rubber compositions for tires with improved processability and abrasion resistance (see claim 1, paragraphs

[0001] until

[0003] Tire wear is largely determined by the glass transition temperature of the rubber (tan delta max peak, DMA). An improvement in the rolling resistance of the tires produced is not described in US 2019 / 0233622 A1. Rolling resistance is influenced by materials that change the tan delta at 60°C. Wear and rolling resistance are independent variables, and a person skilled in the art would not necessarily conclude from an improvement in one that the other is improved. One object of the present invention is to develop a new additive for winter and all-season tires that improves the processing properties of the rubber composition used to produce these tires.At the same time, the other performance properties of the tires, in particular rolling resistance and snow grip and dry grip, as well as tire wear, should not be impaired or even at least partially improved. A further object of the invention is to improve the extrusion properties as well as the quality of the surfaces and edges of extrudates (Garvey dies) produced from the rubber composition. Summary of the invention The object is achieved according to the invention by a rubber composition which contains rubber and at least one rubber additive, characterized in that the at least one rubber additive comprises fatty acid esters, which fatty acid esters consist of at least one C8 to C 22-fatty acid and at least one compound selected from C2- to C4-alkoxylate of a polyol, polyethylene glycol, polypropylene glycol and / or copolymer of ethylene oxide and propylene oxide. A further aspect of the present invention relates to the use of fatty acid esters of at least one C8- to C 22-fatty acid and at least one compound selected from C2 to C4 alkoxylate of a polyol, polyethylene glycol, polypropylene glycol and / or copolymer of ethylene oxide and propylene oxide as a rubber additive in a rubber composition for improving the Mooney viscosity and / or extrusion properties of the rubber composition and / or for improving at least one of abrasion, wet grip and / or rolling resistance of a tire produced from the rubber composition. A further aspect of the present invention relates to a process for producing a tire, characterized in that one or more components of the tire are produced from a rubber composition as defined herein and the rubber composition is cured.A further aspect of the present invention relates to a tire in which at least one component is at least partially made from a rubber composition as defined herein, and the tire is preferably an all-season or winter tire, wherein the component is in particular a tread. Preferred embodiments are the subject of the dependent claims. Embodiments of the invention include the following. the listed components and can in particular consist of these. Brief description of the figures Figures 1a-d show various extrudates (after 24 hours and after one week, at 60 l / min and 15 l / min) which were produced from the rubber compositions A and B as described in example 3 (Figure 1a: after 24 hours at 15 l / min; Figure 1b: after 24 hours at 60 l / min; Figure 1c: after one week at 15 l / min; Figure 1d: after one week at 60 l / min). Figures 2a-b show various extrudates after 24 hours (at 60 l / min and 15 l / min) which were produced from the rubber compositions C and D as described in example 4 (Figure 2a: after 24 hours at 15 l / min; Figure 2b: after 24 hours at 60 l / min).Figures 3a-d show various extrudates (after 24 hours and after one week, at 60 rpm and 15 rpm) produced from rubber compositions E and F as described in Example 5 (Figure 3a: after 24 hours at 15 rpm; Figure 3b: after 24 hours at 60 rpm; Figure 3c: after one week at 15 rpm; Figure 3d: after one week at 60 rpm). Figures 4a-b show various extrudates (at 15 rpm and 60 rpm) produced from rubber compositions G to J as described in Example 6 (Figure 4a: after 24 hours at 15 rpm; Figure 4b: after 24 hours at 60 rpm). Figure 5 shows the material pressure curve of the rubber compositions G to J from Example 6 at various shear rates. Detailed Description of the Invention The inventors have surprisingly found that fatty acid esters consisting of at least one C8 to C. 22- fatty acid (fatty acid component, as further defined below) and at least one compound selected from C2 to C4 alkoxylate a polyol, polyethylene glycol, polypropylene glycol and / or copolymer of ethylene oxide and propylene oxide (polyol component, as defined in more detail below), have positive properties in a rubber composition. The components of the rubber composition according to the invention are described in more detail below. All statements also apply to the tire according to the invention, in which at least one component consists at least partially of the rubber composition according to the invention, its production and the inventive use of the fatty acid esters defined herein. The term phr (parts per hundred parts of rubber by weight) used in this document is the quantity commonly used in the rubber industry for mixture formulations.The dosage of the parts by weight of the individual substances in this document is based on 100 parts by weight of the total mass of all high-molecular-weight and therefore solid rubbers present in the mixture. Polyol component The fatty acid ester according to the invention is prepared from at least one compound selected from C2 to C4 alkoxylate of a polyol, polyethylene glycol, polypropylene glycol and / or copolymer of ethylene oxide and propylene oxide (polyol component), which is polymerized with a C8 to C. 22 -fatty acid. In one embodiment, the polyol component has 2 to 8 hydroxyl groups, such as 2 to 6 hydroxyl groups. Preferably, the polyol component has between 2 and 4 hydroxyl groups. In a particularly preferred embodiment, the polyol component used to produce the fatty acid ester has 2 or 3 hydroxyl groups. In a preferred embodiment, the polyol component has no aromatic groups. In a preferred embodiment, the polyol component according to the invention consists only of carbon, hydrogen, and oxygen. In one embodiment, the fatty acid ester is C8 to C 22-fatty acid and at least one polyether such as polyethylene glycol (PEG), polypropylene glycol (PPG) and / or a copolymer of ethylene oxide and propylene oxide. The copolymers of ethylene oxide and propylene oxide can be random copolymers or block copolymers. It is known to those skilled in the art that polyethers with higher molecular weights are polymolecular, ie, they consist of distributions of macromolecules with different molecular weights. According to the invention, polyethylene glycols, polypropylene glycols and / or copolymers of ethylene oxide and propylene oxide with an average molecular weight in the range of about 200 to 1500 g / mol can be used, e.g. 200 to 800 g / mol, such as about 400 g / mol, to produce the fatty acid ester. In one embodiment, the fatty acid ester according to the invention is prepared from polyethylene glycol (PEG), polypropylene glycol (PPG) and / or copolymer of ethylene oxide and propylene oxide, which is provided with a C8 to C 22-fatty acid. In one embodiment, the fatty acid ester according to the invention is prepared from polyethylene glycol or polypropylene glycol. In one embodiment, the fatty acid ester is prepared from at least one polyethylene glycol or polypropylene glycol having a molecular weight of 200 to 800 g / mol, in particular 400 g / mol to 600 g / mol. In one embodiment, the fatty acid ester is prepared from at least one polyethylene glycol having a molecular weight of 200 (PEG 200) to 800 g / mol (PEG 800), such as 400 to 600 g / mol, in particular 400 g / mol (PEG 400). In a further embodiment, the fatty acid ester is prepared from at least one polypropylene glycol having a molecular weight of 200 to 800 g / mol, such as 400 to 600 g / mol, in particular 600 g / mol. In one embodiment, the fatty acid ester is prepared from at least one random copolymer of ethylene oxide and propylene oxide having a molecular weight of 200 to 800 g / mol, such as 400 to 600 g / mol, in particular 400 g / mol. In a preferred embodiment, the random copolymer of ethylene oxide and propylene oxide has an ethylene oxide group content of 10 to 30 wt. %. In a further embodiment, the fatty acid ester is prepared from at least one block copolymer of ethylene oxide and propylene oxide having a molecular weight of 50 to 4500 g / mol, such as 200 to 3000, and in particular 500 to 2500 g / mol. According to a preferred embodiment, the ethylene oxide / propylene oxide block copolymer has an ethylene oxide group content of 10 to 80 wt.-%, such as 10 to 55 wt.%. The block copolymers can be constructed by having polyoxyethylene groups in the middle of the polypropylene glycol molecule and at both ends. The ethylene oxide / propylene oxide block copolymers to be used according to the invention are commercially available compounds. They can be produced by reacting polypropylene glycol with ethylene oxide. Examples of ethylene oxide / propylene oxide block copolymers are the Pluronic PE polymers from BASF SE, such as Pluronic PE 3100, Pluronic PE 3500, Pluronic PE 4300, Pluronic PE 6100, Pluronic PE 6120, Pluronic PE 6200, Pluronic PE 6400, Pluronic PE 6800, Pluronic PE 8100, Pluronic PE 9200, Pluronic PE 9400, Pluronic PE 10100, Pluronic PE 10300, Pluronic PE 10400, and Pluronic PE 10500. In a further embodiment, the fatty acid ester is made from at least one C2 to C4 alkoxylate of a polyol. Polyols are understood to be substances that have at least two free hydroxyl groups.The hydrocarbon part of the polyol is a group containing carbon and. Contains hydrogen, with at least two carbon atoms bonded to a hydroxyl group. It can be straight-chain or branched, especially straight-chain, and optionally interrupted by a heteroatom. A C2- to C4-alkoxylate of a polyol is a polyol that has been reacted with a C2- to C4-alkylene oxide, where several reactions can take place in succession at one hydroxyl group of the polyol. Examples of C2- to C4-alkylene oxides are ethylene oxide, propylene oxide, and 1-butene oxide. The reaction of the polyols with the C2- to C4-alkylene oxide is carried out using conventional methods. It is also possible to use mixed C2 to C4 alkoxylates in which a polyol is reacted using a mixture of C2 to C4 alkylene oxides (mixture of ethylene oxide and propylene oxide and / or 1-butylene oxide). In a preferred embodiment, the fatty acid ester is made from at least one polyol alkoxylate with up to 10, such as 5 to 10, e.g.7 alkylene oxide units. The C2- to C4 alkoxylate of a polyol can have an average molecular weight in the range of about 200 to 1500 g / mol, such as about 200 to 800 g / mol, in particular 300 to 500 g / mol. In one embodiment, the C2- to C4 alkoxylate of a polyol has 2 to 8 hydroxyl groups, such as 2 to 6 hydroxyl groups. In a preferred embodiment, the C2- to C4 alkoxylate of a polyol used to prepare the fatty acid ester has between 2 and 4 hydroxyl groups, such as 2 or 3 hydroxyl groups. In a preferred embodiment, the fatty acid ester is prepared from at least one polyol ethoxylate having up to 10, such as 5 to 10, e.g. 7 ethylene oxide units (EO units). In a further preferred embodiment, the fatty acid ester consists of at least one polyol propoxylate with up to 10. such as 5 to 10, e.g., 7, propylene oxide units (PO units). The polyol ethoxylate or polyol propoxylate preferably has between 2 and 4 hydroxyl groups. The polyol of the C2- to C4-alkoxylate can be a C2- to C 15 -polyol. This means that the polyol has 2 to 15 carbon atoms. As C2- to C 15 -Polyol component of the alkoxylate is preferably C2 to C 10-Polyol and in particular C2- to C6- polyol are used. The polyols preferably have 2 to 8 hydroxyl groups, such as 2 to 8 and in particular 2 to 4 hydroxyl groups, such as 2 or 3 hydroxyl groups. Examples of polyols that can be reacted with a C2-C4 alkylene oxide are ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,3-propanediol, glycerin, pentaerythritol, dipentaerythritol, tripentaerythritol, trimethylolethane, trimethylolpropane and mixtures thereof. Preferably, the polyol of the C2- to C4 alkoxylate is selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, glycerin and mixtures thereof and is in particular glycerin. Sugar alcohols such as sorbitol, maltitol, mannitol, xylitol and mixtures thereof can also be used as polyols that can be reacted with a C2-C4 alkylene oxide.This has the further advantage that the fatty acid esters produced in this way can be produced more sustainably. In a preferred embodiment, the polyol component of the fatty acid ester is a substance from the group consisting of polyethylene glycol, polypropylene glycol, ethoxylated glycerin, ethoxylated trimethylolpropane, ethoxylated pentaerythritol, ethoxylated sorbitol, and / or mixtures thereof. In a particularly preferred embodiment, the fatty acid ester is from C8 to C 22-fatty acid and ethoxylated glycerol, which in particular has up to 10, such as 5 to 10, e.g. 7, ethylene oxide units. A glycerol of this kind according to the invention is commercially available, for example, as Aduxol-Gly-07 from Schärer & Schläpfer. In one embodiment, only one polyol component is used to produce the fatty acid ester (this includes, however, those higher molecular weight alcohols which have a certain molecular weight distribution, such as PEG 400). In a further embodiment, at least two different polyol components are used to produce the fatty acid ester. For example, a mixture of PEG, PPG and / or PEG-PPG copolymer can be used to produce the fatty acid ester. Fatty acid component The fatty acid component according to the invention is based on C8 to C 22-fatty acids. This means that the fatty acids have 8 to 22 carbon atoms. It should be noted that fatty acids are usually understood to mean aliphatic saturated and unsaturated carboxylic acids with almost exclusively unbranched carbon chains (see, for example, Römpp Chemie Lexikon, 9th edition 1990, Volume 2, p. 1343). According to the invention, "fatty acids" also include acids that have unsaturation. Furthermore, branches or heteroatoms may be present, as long as this does not significantly impair the aliphatic character of the acids. The fatty acid component according to the invention is thus based on at least one saturated or unsaturated, branched or unbranched (= linear) C8 to C 22 -fatty acid. In one embodiment of the invention, the fatty acid component according to the invention consists of a mixture of different fatty acids. The fatty acid component can contain at least two, such as at least three, four or five different C8 to C 22 - fatty acids. Typical examples of fatty acids that can be used as fatty acid components in the present invention are caprylic acid, pelargonic acid, capric acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, palmitoleic acid, margaric acid, stearic acid, oleic acid, elaidic acid, vaccenic acid, petroselinic acid, linoleic acid, linolenic acid, ricinoleic acid, 12-hydroxystearic acid, arachidic acid, gadoleic acid, gondoic acid, behenic acid, cetoleic acid and erucic acid. In a preferred embodiment, the fatty acid component according to the invention consists only of carbon, hydrogen and oxygen. The fatty acid component according to the invention can contain at least one saturated or unsaturated, branched or unbranched (= linear) C 10 - to C 22 – fatty acid. Preferably, the fatty acid component according to the invention comprises at least one C12 - to C 22 – Fatty acid, especially a mono- or polyunsaturated, branched or unbranched (= linear) C 16 - to C 20 -fatty acid or mixtures thereof. In a preferred embodiment, the fatty acid component according to the invention comprises at least one mono- or di-unsaturated C 16 - to C 20 -fatty acid. A diunsaturated fatty acid is a fatty acid whose carbon chain has two double bonds. In a particularly preferred embodiment, the fatty acid component according to the invention comprises at least one monounsaturated C 16 - to C 20 fatty acid and at least one diunsaturated C 16 - to C 20 -fatty acid. In a further particularly preferred embodiment, the fatty acid component according to the invention comprises at least one monounsaturated C 16 - to C 20-fatty acid, at least one diunsaturated C 16 - to C 20 fatty acid and at least one triunsaturated C 16 - to C 20 -fatty acid. In a preferred embodiment, the fatty acid component according to the invention comprises at least one C 18 - fatty acid, especially a C 18:1 - fatty acid, such as oleic acid and / or a C 18:2 - fatty acid. A C 18:1 - Fatty acid is a fatty acid with 18 carbon atoms, whose carbon chain has a double bond. A C 18:2 - Fatty acid is a fatty acid with 18 carbon atoms, whose carbon chain has two double bonds. In a preferred embodiment, the fatty acid component according to the invention comprises at least one C 18:1 - fatty acid and at least one C 18:2 - fatty acid. In a further preferred embodiment, the fatty acid component according to the invention comprises at least one C 18:1- fatty acid, at least one C 18:2 - fatty acid and at least one C 18:3 - Fatty acid. It is known to those skilled in the art that commercial products used to produce fatty acid esters generally contain mixtures of fatty acids. Furthermore, the fatty acids can also be in the form of technical cuts, such as those obtained during pressure splitting or saponification of natural fats and oils, for example palm oil, palm kernel oil, coconut oil, olive oil, soybean oil, sunflower oil, rapeseed oil, or beef tallow. In one embodiment, the fatty acid ester according to the invention is produced from a mixture of fatty acids containing at least 50% by weight, such as at least 75% by weight, in particular at least 90% by weight of C8 to C10 22 -fatty acids. In one embodiment, the fatty acid ester according to the invention is prepared from a mixture of fatty acids which contains at least 50 wt.%, such as at least 75 wt.%, in particular at least 90 wt.% C 12 - to C 20-fatty acids. In one embodiment, the fatty acid ester according to the invention is prepared from a mixture of fatty acids containing at least 50% by weight, such as at least 75% by weight, in particular at least 90% by weight of C 16 - to C 20 -fatty acids. Preferably, the mixture of fatty acids comprises 50 to 100 wt.%, such as 75 to 100 wt.%, in particular 90 to 100 wt.% C 16 - to C 20 - fatty acids. In one embodiment, the fatty acid ester according to the invention is prepared from a mixture of fatty acids containing at least 50% by weight, such as at least 65% by weight, in particular at least 75% by weight of saturated or mono- or polyunsaturated C 18 -fatty acids. In one embodiment, the fatty acid ester according to the invention is prepared from a mixture of fatty acids containing 50 to 95% by weight, such as 65 to 90% by weight, in particular 70 to 85% by weight of saturated or mono- or polyunsaturated C 18- fatty acids. Preferably, the mixture of fatty acids used for the preparation contains at least 1 wt.% saturated C 18 - Fatty acid, 10 wt% C 18:1 - fatty acid and / or at least 5% by weight C 18:2 - fatty acid. In one embodiment, the mixture of fatty acids comprises at least 50 wt%, such as at least 65 wt%, in particular at least 70 wt% C 18:1 - Fatty acid, especially oleic acid. In one embodiment, the mixture of fatty acids comprises 50 to 90 wt%, such as 65 to 85 wt%, in particular 70 to 80 wt% C 18:1 - Fatty acid, especially oleic acid. In one embodiment, the mixture of fatty acids comprises 0.1 to 30 wt.%, such as 1 to 15 wt.%, in particular 5 to 12 wt.% C 18:2 - Fatty acid, especially linoleic acid. In a preferred embodiment, the mixture of fatty acids comprises 65 to 85 wt% C 18:1 - fatty acid and 1 to 15 wt% C 18:2- fatty acid. In a further embodiment, the mixture of fatty acids comprises at least 5 wt%, such as at least 10 wt%, in particular at least 15 wt% C 18:1 - Fatty acid, especially oleic acid. The mixture of fatty acids may contain 5 to 50 wt%, such as 10 to 40 wt%, especially 15 to 35 wt% C 18:1 - fatty acid, especially oleic acid. The mixture of fatty acids may contain 10 to 90 wt%, such as 25 to 75 wt%, especially 40 to 65 wt% C 18:2 - fatty acid, especially linoleic acid. In a preferred embodiment, the mixture of fatty acids comprises 10 to 40 wt.% C 18:1 - fatty acid and 25 to 75 wt% C 18:2 - Fatty acid, such as 15 to 35 wt% C 18:1 - fatty acid and 40 to 65 wt% C 18:2 - fatty acid. Furthermore, the mixture of fatty acids can contain 0.1 to 30 wt.%, such as 1 to 20 wt.%, in particular 2 to 15 wt.% C 18:3- fatty acid. In a particularly preferred embodiment, the mixture of fatty acids comprises 10 to 40 wt.% C 18:1 - Fatty acid, 25 to 75 wt% C 18:2 - fatty acid and 1 to 20 wt% C 18:3 - fatty acid. In particular, the mixture of fatty acids comprises 15 to 35 wt% C 18:1 - fatty acid and 40 to 65 wt% C 18:2 - fatty acid and 2 to 15 wt% C 18:3 - Fatty acid. The acid number of the fatty acid or fatty acid mixture used is preferably 100 to 300 mg KOH / g, especially 150 to 250 mg KOH / g. The acid number is measured using DIN EN ISO 2114. The saponification number of the fatty acid or fatty acid mixture used is preferably 100 to 300 mg KOH / g, in particular 150 to 250 mg KOH / g. The saponification number indicates the amount of potassium hydroxide in mg required to saponify 1 g of the sample to be analyzed. The saponification number is measured using DIN EN ISO 3681. The iodine number of the fatty acid or fatty acid mixture used is preferably 10 to 200 g iodine / 100 g, in particular 50 to 150 g iodine / 100 g. The iodine number indicates the degree of unsaturation of the sample. The iodine number is measured using DIN EN ISO 39612018-1. Fatty acid esters The esterification of the polyols with the fatty acids can be carried out in a known manner.Acidic catalysts that can be used here include, for example, hypophosphorous acid, methanesulfonic acid, butanesulfonic acid, p-toluenesulfonic acid, naphthalenesulfonic acid, alkylbenzenesulfonic acid, sulfosuccinic acid, and / or mixtures thereof. It is also recommended to carry out the esterification at elevated temperatures, for example at 140 to 250°C, preferably at 180 to 240°C. In a preferred embodiment, the fatty acid ester is prepared by heating in hypophosphorous acid. As described above, the fatty acid ester can be prepared from a mixture of different fatty acids and / or polyols. In one embodiment, the fatty acid ester according to the invention consists only of carbon, hydrogen, and oxygen. In one embodiment, the fatty acid ester according to the invention is prepared from at least one C2 to C4 alkoxylate of a C2 to C6 polyol and at least one C. 12 - to C 22-fatty acid, preferably at least one unsaturated C 16 - to C 20 - fatty acid. The fatty acid ester is preferably a partial ester (ie not all -OH groups of the polyol from which the ester is formed are esterified) and is in particular at least 40 wt.%, such as at least 70 wt.%, based on the total mass of partial and complete esters, a mono-fatty acid ester of one or a mixture of C8 to C 22 - fatty acids. In one embodiment, the fatty acid ester according to the invention consists essentially of monofatty acid ester. In one embodiment, the fatty acid ester according to the invention is a monofatty acid ester of C2 to C4 alkoxylate of a C2 to C6 polyol and at least one C 16 - to C 20 -fatty acid, preferably an unsaturated C 16 - to C 20-fatty acid. In a further embodiment, the fatty acid ester according to the invention is a monofatty acid ester of polyethylene glycol and at least one C 12 - to C 22 -fatty acid, preferably at least one unsaturated C 16 - to C 20 -fatty acid. In a further embodiment, the fatty acid ester according to the invention is a monofatty acid ester of polypropylene glycol and at least one C 12 - to C 22 -fatty acid, preferably at least one unsaturated C 16 - to C 20 -fatty acid. In a further embodiment, the fatty acid ester according to the invention is a monofatty acid ester of a copolymer of ethylene oxide and propylene oxide and at least one C 12 - to C 22 - fatty acid, preferably at least one unsaturated C 16 - to C 20-fatty acid. The copolymer of ethylene oxide and propylene oxide can be a random copolymer or block copolymer. In one embodiment, the fatty acid ester according to the invention is a mixture of monofatty acid esters of polyethylene glycol or polypropylene glycol, wherein the mixture of fatty acids used for the preparation contains at least 50 wt.% C 16 - to C 20 - fatty acids, preferably at least 50% by weight saturated or (poly)unsaturated C 18 - fatty acid. The product used to produce The mixture of fatty acids used in the preparation may contain 50 to 95 wt%, such as 65 to 90 wt%, in particular 70 to 85 wt% saturated or (poly)unsaturated C 18 -fatty acids. Preferably, the mixture comprises at least 10% C 18:1 - fatty acid and / or at least 5% by weight C 18:2- fatty acid. In a preferred embodiment, the fatty acid ester according to the invention is a mixture of monofatty acid esters of polyethylene glycol or polypropylene glycol, wherein the mixture of fatty acids used for the preparation contains 65 to 85 wt.% C 18:1 - fatty acid and / or 1 to 15 wt% C 18:2 - fatty acid. In a further preferred embodiment, the fatty acid ester according to the invention is a mixture of monofatty acid esters of polyethylene glycol or polypropylene glycol, wherein the mixture of fatty acids used for the preparation contains 10 to 40 wt.% C 18:1 - fatty acid and / or 25 to 75 wt% C 18:2 - fatty acid and / or 1 to 20 wt% C 18:3 - fatty acid. In particular, the mixture of fatty acids comprises 15 to 35 wt% C 18:1 - fatty acid and 40 to 65 wt% C 18:2 - fatty acid and 2 to 15 wt% C 18:3- fatty acid. In one embodiment, the fatty acid ester according to the invention is an ester of polyol ethoxylate or polyol propoxylate and a C8 to C 22 -Fatty acid ester mixture, preferably a C 12 - to C 22 -Fatty acid ester mixture. In one embodiment, the fatty acid ester according to the invention is an ester of ethoxylated glycerol or trimethylolpropane, which has up to 10, such as 5 to 10, ethylene oxide units, and a fatty acid ester mixture, wherein the mixture of fatty acids used for the preparation contains at least 50 wt.% C 16 - to C 20 - Fatty acids, preferably 50 to 95 wt% saturated or unsaturated C 18 - fatty acid. In a preferred embodiment, the fatty acid ester according to the invention is an ester of ethoxylated glycerol or ethoxylated trimethylolpropane, which has up to 10, such as 5 to 10 ethylene oxide units, and a fatty acid ester mixture, wherein the mixture of fatty acids used for the preparation contains 65 to 85 wt.% C 18:1 - fatty acid and / or 1 to 15 wt% C 18:2 - fatty acid. In a further preferred embodiment, the fatty acid ester according to the invention is an ester of ethoxylated glycerol or ethoxylated trimethylolpropane, which has up to 10, such as 5 to 10, ethylene oxide units, and a fatty acid ester mixture, wherein the mixture of fatty acids used for the preparation contains 10 to 40 wt.% C 18:1 - fatty acid and / or 25 to 75 wt% C 18:2 - fatty acid and / or 1 to 20 wt% C 18:3- fatty acid. In a preferred embodiment, the fatty acid ester according to the invention is a monoester of ethoxylated glycerol or ethoxylated trimethylolpropane, which has 5 to 10 ethylene oxide units, and a fatty acid ester mixture, wherein the mixture of fatty acids used for the preparation preferably contains at least 50% by weight of saturated or unsaturated C 18 - Fatty acid, in particular 65 to 85 wt%, C 18:1 - fatty acid and / or 1 to 15 wt% C 18:2 - fatty acid. In a further preferred embodiment, the fatty acid ester according to the invention is a monoester of ethoxylated glycerol or ethoxylated trimethylolpropane, which has up to 10, such as 5 to 10, ethylene oxide units, and a fatty acid ester mixture, wherein the mixture of fatty acids used for the preparation contains 10 to 40 wt.% C 18:1 - fatty acid and / or 25 to 75 wt% C 18:2 - fatty acid and / or 1 to 20 wt% C 18:3- fatty acid. In one embodiment, the fatty acid ester has an acid number (AN) of 0 to 10 mg KOH / g, such as 2 to 8 mg KOH / g. The acid number can be measured using DIN EN ISO 2114. In one embodiment, the fatty acid ester has a hydroxyl number (OHN) of 5 to 200 mg KOH / g, such as 100 to 190 mg KOH / g and 120 to 180 mg KOH / g. The hydroxyl number is the amount of potassium hydroxide (KOH) in milligrams (mg) corresponding to the hydroxyl groups that are acetylated in 1 gram of the tested product under specified test conditions. The hydroxyl number can be measured using DIN-EN-ISO 4629-1:2016-12. In one embodiment, the fatty acid ester has a pour point of 5 to -50°C, such as 0 to -40°C and -10 to -30°C. The pour point is the lowest temperature at which the oil just flows when cooled under specified conditions. The pour point can be measured using DIN-ISO 3016. In one embodiment, the fatty acid ester has a dynamic viscosity of 50 to 1000 mPas, such as 70 to 700 mPas and 100 to 400 mPas. Dynamic viscosity is defined as the quotient of the shear stress and the velocity gradient. Dynamic viscosity can be measured using DIN-ISO 3219.A viscometer (e.g., a Roto Visko 1 viscometer from Haake) or a rheometer (e.g., Modular Compact 302 from Anton Paar) can be used for this purpose. Rubber additive: The rubber composition according to the invention contains at least one rubber additive comprising fatty acid esters. In one embodiment, the rubber additive can consist of the fatty acid ester. Alternatively, the rubber additive contains at least 50% by weight, preferably at least 70% by weight, in particular at least 90% by weight of fatty acid ester. In addition to the fatty acid ester, the rubber additive can also comprise further constituents. In a preferred embodiment, the rubber additive contains fatty acid esters and / or fatty acid soaps, in particular zinc and / or potassium fatty acid soaps. The rubber additives of the present invention can preferably be present in a blend containing one or more solid carrier materials and one or more fatty acid esters, as well as optionally further constituents. Preferably, inorganic fillers (such as, for example, silicas) or waxy materials (such as, for example, polyethylene waxes) can be used as the carrier material. In a preferred variant, a silica is used as the carrier material. Examples of commercially available silicas that can be used in the blend of the present invention are Sipernat 22 and Sipernat 50 from Evonik. Amides, amino alcohols, and soaps, for example, can be used as further constituents in the blend. It is also possible for several fatty acid esters according to the invention to be present in one blend.The weight ratio of carrier material to fatty acid ester in the blend is, for example, 10 / 90 to 90 / 10, more preferably 20 / 80 to 80 / 20, and particularly preferably about 30 / 70 or 33 / 67. The use of a blend facilitates handling of the fatty acid esters, in particular when they are liquid at room temperature. Rubber The rubber composition according to the invention contains at least one rubber. In a preferred embodiment, the rubber is a rubber that can be crosslinked by sulfur crosslinking. According to the invention, rubbers are used that are particularly suitable for producing tread compounds that can be used in tire production. Preferred rubbers are diene rubbers. Diene rubbers are rubbers that are formed by polymerization or copolymerization of dienes and / or cycloalkenes and thus have C=C double bonds either in the main chain or in the side groups. Preferred diene rubbers are butadiene rubber, polyisoprene, and styrene-butadiene rubber. In a preferred embodiment, the rubber composition comprises at least one styrene-butadiene rubber, natural rubber, polyisoprene, and / or butadiene rubber, and optionally functionalized forms thereof. In a preferred embodiment, the rubber composition contains at least one styrene-butadiene rubber (styrene-butadiene copolymer).This can be either solution-polymerized styrene-butadiene rubber (SSBR) or emulsion-polymerized styrene-butadiene rubber (ESBR), although a mixture of at least one SSBR and at least one ESBR can also be used. The terms "styrene-butadiene rubber" and "styrene-butadiene copolymer" are used synonymously within the scope of the present invention. The styrene-butadiene copolymer(s) used can be end-group modified and / or functionalized along the polymer chains. The modification may be one with hydroxy groups and / or ethoxy groups and / or epoxy groups and / or siloxane groups and / or amino groups and / or aminosiloxane and / or carboxy groups and / or phthalocyanine groups and / or silane sulfide groups.However, other modifications known to the expert, also referred to as functionalizations, are also possible. Such functionalizations can include metal atoms. The butadiene rubber (= BR, polybutadiene) can be any type known to the expert. These include, among others, the so-called high-cis and low-cis types, with polybutadiene having a cis content of greater than or equal to 90 wt.% being preferred. as high-cis type and polybutadiene with a cis content of less than 90 wt. % is referred to as low-cis type. An example of a low-cis polybutadiene is Li-BR (lithium-catalyzed butadiene rubber) with a cis content of 20 to 50 wt. %. The polybutadiene used can be end-group modified and / or functionalized along the polymer chains. Reference is made in this regard to the possibilities disclosed above in connection with the modification and functionalization of styrene-butadiene rubber, optionally adapted to the requirements of BR as a rubber material. According to a preferred embodiment, the rubber composition contains at least one styrene-butadiene rubber, preferably in amounts of 40 to 100 phr, particularly preferably 70 to 90 phr. Furthermore, oil-extended rubber can also be added to the rubber compositions according to the invention.With regard to the amounts of oil-extended rubber used, it is common practice to "weigh in" the oil content, which can result in formulations with "rubber" amounts of over 100 phr, such as up to 200 phr, e.g., in the range of 40 or 70 to 140 or 150 phr. Since the oil content is usually known, oil-extended rubber can, however, be added such that the sum of the solid rubber components (cf. the definition above) is such that a total of 100 parts by weight of rubber is present. In one embodiment, the rubber additive is used to reduce the amount of oil in oil-extended rubber. In this case, less oil is used in the rubber composition according to the invention than would be the case in a rubber composition with oil-extended rubber without the rubber additive.According to a preferred embodiment, the rubber composition contains at least one styrene-butadiene rubber which is present at the polymer chain ends and / or along the. Polymer chains (English: “backbone functionalized”) are functionalized with at least one of the above-mentioned groups. The functional groups are particularly preferably groups that can bind to silica, such as in particular hydroxyl groups and / or ethoxy groups and / or epoxy groups and / or siloxane groups and / or aminosiloxane and / or carboxy groups and / or silane sulfide groups. According to a preferred embodiment, the rubber composition contains 5 to 95 phr, preferably 10 to 30 phr, of at least one butadiene rubber. The rubber composition according to the invention can also contain natural and / or synthetic polyisoprene. Both cis-1,4-polyisoprene and 3,4-polyisoprene can be used here. The rubber composition preferably contains cis-1,4-polyisoprenes with a cis-1,4 content of more than 90 wt.%. Natural rubber is a rubber with a high cis-1,4 content.The polyisoprene used can also be end-group modified and / or functionalized along the polymer chains. Reference is made in this regard to the possibilities disclosed above in connection with the modification and functionalization of styrene-butadiene rubber, optionally adapted to the requirements of polyisoprene as a rubber material. The rubbers mentioned can also be present in combination with one another in the rubber composition. In a preferred embodiment, the rubber composition comprises at least one styrene-butadiene rubber and at least one butadiene rubber, in particular 5 to 95 phr of butadiene rubber and 5 to 80 phr of styrene-butadiene rubber. In a further preferred embodiment, the rubber composition comprises at least one styrene-butadiene rubber, at least one butadiene rubber and at least one natural rubber, in particular 5 to 80 phr of butadiene. Rubber, 5 to 80 phr of styrene-butadiene rubber, and 5 to 60 phr of natural rubber. In a preferred embodiment, the rubber composition comprises at least one liquid polymer (viscous liquids at normal temperature) such as LIR (liquid polyisoprene), LBR (liquid polybutadiene), and L-SBR (liquid styrene-butadiene). Examples of liquid polyisoprene that can be used are Kurapren LIR30 and Kurapren LIR50 from Kuraray Co., Ltd. Examples of liquid polybutadiene that can be used are LBR-302, LBR-307, LBR-305, LBR-352, or LBR-361 from Kuraray Co., Ltd. As liquid styrene-butadiene, for example, L-SBR-820 or L-SBR-841 from Kuraray Co., Ltd. can be used. In addition, the rubber composition according to the invention can contain other rubbers in comparatively small amounts, such as 0.1 to 50 phr.Further additives The rubber composition of the present invention may contain further additives and constituents, in particular one or more fillers, one or more catalysts or activators for sulfur crosslinking, and optionally further additives. In a preferred embodiment, the rubber composition of the present invention contains further additives and constituents suitable for the production of tread compounds for tires. The rubber composition preferably contains at least one filler. The rubber composition may contain 5 to 300 phr, preferably 30 to 300 phr, in particular 50 to 200 phr of at least one filler, where this refers to the total amount of all fillers present. According to a preferred embodiment of the invention, the total filler content is 30 to 150 phr, more preferably 60 to 140 phr, again preferably 80 to 130 phr, again more preferably 100 to 130 phr, and again most preferably 110 to 130 phr. These can be any fillers known to those skilled in the art, such as carbon black, carbon nanotubes, silica, aluminosilicates, layered silicates such as kaolin, calcium carbonate (chalk), starch, calcium carbonate, barium sulfate, magnesium oxides, aluminum oxides, titanium dioxide, or rubber gels. The rubber composition preferably contains at least one silica as filler. The silicas can be those known to those skilled in the art that are suitable as fillers for rubber compositions.However, it is particularly preferred to use a finely divided, precipitated silica which has a nitrogen surface area (BET surface area) (according to DIN ISO 9277) of 35 to 350 m2 / g, preferably of 35 to 260 m2 / g, particularly preferably of 100 to 260 m2 / g and very particularly preferably of 115 to 235 m2 / g, and a CTAB surface area (according to ASTM D 3765) of 30 to 400 m2 / g, preferably of 30 to 250 m2 / g, particularly preferably of 80 to 250 m2 / g and very particularly preferably of 80 to 230 m2 / g. Suitable silicas are therefore, for example: For example, both Ultrasil® 7000 GR (trade name) from Evonik and Ultrasil® VN3 (trade name) from Evonik, as well as highly dispersible silicas, so-called HD silicas (e.g. Zeosil® 1165 MP from Solvay), are used. To improve processability and to bind the silica and other potentially harmful substances,Silane coupling agents can be used in rubber compositions to bond existing polar fillers to the rubber. One or more different silane coupling agents can be used in combination. The rubber composition can thus contain a mixture of different silanes. The silane Coupling agents react with the surface silanol groups of the silica or other polar groups during mixing of the rubber or rubber composition (in situ) or even before the addition of the filler to the rubber, as a pretreatment (premodification). Silane coupling agents that can be used are all silane coupling agents known to the person skilled in the art for use in rubber compositions. Such coupling agents known from the prior art are bifunctional organosilanes that have at least one alkoxy, cycloalkoxy, or phenoxy group as a leaving group on the silicon atom and that have, as another functionality, a group that can, if necessary, enter into a chemical reaction with the double bonds of the polymer after cleavage.Furthermore, it is advantageous if the rubber composition according to the invention contains at least one plasticizer, the total amount of plasticizer preferably being 5 to 150 phr. The plasticizers used in the context of the present invention include all plasticizers known to the person skilled in the art, such as aromatic, naphthenic, or paraffinic mineral oil plasticizers, such as MES (mild extraction solvate) or RAE (residual aromatic extract) or TDAE (treated distillate aromatic extract), or rubber-to-liquid oils (RTL) or biomass-to-liquid oils (BTL), preferably with a polycyclic aromatics content of less than 3% by weight according to method IP 346 or factitious oils, or plasticizer resins or natural oils (sunflower oil, rapeseed oil). The rubber composition can contain 5 to 40 phr, preferably 10 to 30 phr, of plasticizer.In one embodiment, the rubber additive is used to reduce the amount of plasticizer in the rubber composition or to replace a plasticizer. In this case, less plasticizer is used in the rubber composition according to the invention than would be the case in a rubber composition without the rubber additive. This can be advantageous in certain cases, for example, for environmental or economic reasons. The rubber composition preferably also contains substances required for crosslinking, such as zinc oxide, accelerators, and / or sulfur. It is particularly advantageous if the rubber composition according to the invention contains zinc oxide or zinc-containing compounds for activating sulfur vulcanization. The vulcanization of the rubber composition is optionally carried out in the presence of sulfur and / or sulfur donors and with the aid of vulcanization accelerators, whereby some vulcanization accelerators can also act as sulfur donors, and sulfur and / or sulfur donors and vulcanization accelerators are used in the amounts known in the art. Sulfur and / or sulfur donors and one or more accelerators are added to the rubber composition in the stated amounts in the final mixing step.The accelerator is selected from the group consisting of thiazole accelerators and / or mercapto accelerators and / or sulfenamide accelerators and / or thiocarbamate accelerators and / or thiuram accelerators and / or thiophosphate accelerators and / or thiourea accelerators and / or xanthate accelerators and / or guanidine accelerators. Preference is given to the use of at least one sulfenamide accelerator selected from the group consisting of N-cyclohexyl-2-benzothiazolesufenamide (CBS) and / or N,N-dicyclohexylbenzothiazole-2-sulfenamide (DCBS) and / or benzothiazyl-2-sulfenemorpholide (MBS) and / or 2,2'-dibenzothiazyl disulfide (MBTS) and / or N-tert-butyl-2-benzothiazylsulfenamide (TBBS). Multiple accelerators can also be used. A sulfenamide accelerator, particularly CBS, is preferred in combination with the guanidine accelerator DPG (1,3-diphenylguanidine).The amount of DPG is 0 to 5 phr, preferably 0.1 to 3 phr, particularly preferably 0.5 to 2.5 phr, most preferably 1 to 2.5 phr. Furthermore, the rubber composition may contain conventional additives in conventional parts by weight. The additives may be selected from the list consisting of anti-aging agents, activators, waxes, resins, mastication aids, and processing aids, and mixtures thereof. Examples of anti-aging agents that may be used are N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine (6PPD), N,N'-diphenyl-p-phenylenediamine (DPPD), N,N'-ditolyl-p-phenylenediamine (DTPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), and 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ). The rubber composition according to the invention preferably comprises 0.1 to 3 phr of anti-aging agent. Examples of activators that can be used include zinc oxide and fatty acids (e.g., stearic acid) or zinc complexes such as zinc ethylhexanoate. The rubber composition according to the invention preferably comprises 0.5 to 10 phr, more preferably 2 to 5 phr, of activators.The rubber composition according to the invention preferably comprises 0.1 to 3 phr of waxes. Suitable resins are, in particular, plasticizer resins, such as, for example, C5 petroleum resin, C9 petroleum resin, terpene resin, coumarone indene resin, or a hydrocarbon resin made from alpha-methylstyrene and styrene (AMS resin). The rubber composition according to the invention preferably comprises 5 to 150 phr, more preferably 15 to 50 phr of resins. 2,2'-dibenzamidodiphenyl disulfide (DBD), for example, can be used as a mastication aid. The rubber composition according to the invention preferably comprises 0.1 to 3 phr of mastication aid. Suitable processing aids are, for example, fatty acid salts, such as, for example, zinc soaps. The rubber composition according to the invention preferably comprises 0.5 to 10 phr, preferably 2 to 5 phr, of processing aids. In particular, the rubber composition contains a) 0.1 to 3 phr of anti-aging agents, b) 0.5 to 10 phr, preferably 2 to 5 phr of activators, c) 0.1 to 3 phr of waxes, d) 5 to 100 phr, preferably 15 to 50 phr of resins, e) 0.1 to 3 phr of mastication aids, and f) 0.5 to 10 phr, preferably 2 to 5 phr of processing aids. The proportion of the total amount of further additives is 3 to 150 phr, preferably 3 to 100 phr, and particularly preferably 5 to 80 phr. Composition The rubber composition preferably contains between 0.1 to 40 phr of fatty acid esters, as well as 1 to 40, 2 to 40, 3 to 40, 4 to 40 or 5 to 40. In a preferred embodiment, the rubber composition contains 1 to 30 phr, as well as 2 to 30, 3 to 30, 4 to 30 and in particular 5 to 30 phr of fatty acid esters.The fatty acid esters according to the invention can either be added to an existing rubber composition in a so-called "on top" use (in addition to other plasticizers). In such a case, use concentrations between 0.5 and 5 phr are preferred. The fatty acid esters according to the invention can also be used to replace other plasticizers entirely or at least partially. In such a case, significantly higher use concentrations are advantageous, in particular 5 to 40 or 5 to 30 phr. In a preferred embodiment, the composition has a rolling resistance, tan delta, that is at least 5%, preferably 10%, in particular 15% lower after vulcanization. 60°C, and / or 5%, preferably 10%, in particular 15% higher wet grip, tan delta at 0°C. Furthermore, the composition preferably has improved processability, in particular a Mooney viscosity that is at least 5%, preferably 10%, in particular 15% lower and / or a correspondingly lower material pressure during extrusion. Furthermore, the composition preferably has improved stiffness, in particular a tear strength and / or elongation at break and / or tensile strength modulus 100% and / or tensile strength modulus 300% that is at least 5%, preferably 10%, in particular 15% higher. The above-mentioned improvements (lower rolling resistance, higher wet grip, improved processability, increased stiffness) can be determined in comparison to an otherwise identical composition which, instead of the additive according to the invention, comprises a rubber additive known from the prior art in an identical amount.For testing, two otherwise identical rubber compositions are produced and their properties are then compared. Furthermore, the above-mentioned improvements (lower rolling resistance, higher wet grip, improved processability, increased stiffness) can be determined in comparison to an otherwise identical composition which, instead of the additive according to the invention, comprises a plasticizer known from the prior art in an identical amount. Commercially available materials, such as Tudalen 4192, can be used as known plasticizers. For testing, two otherwise identical rubber compositions are produced and their properties are then compared. The above-mentioned improvements can also be determined in comparison to an otherwise identical composition. which does not contain the rubber additive according to the invention. For testing purposes, two identical rubber compositions are prepared, and the rubber additive according to the invention is additionally added to one of them. The properties of the two rubber compositions are then compared. The rubber composition is preferably suitable for the production of tread compounds for tires. The rubber composition according to the invention is also suitable for treads consisting of different tread compounds arranged side by side and / or one below the other (multi-component treads). Production The rubber additive defined above is generally produced by simply mixing the components. This is continued until a desired homogeneous mixture is achieved. Suitable mixing devices are known to those skilled in the art.The rubber composition according to the invention is produced in a conventional manner, whereby first, as a rule, a base mixture containing all components with the exception of the vulcanization system (sulfur and vulcanization-influencing substances) is prepared in one or more mixing stages. The finished mixture is then produced by adding the vulcanization system. The composition can then be further processed, e.g., by an extrusion process, and brought into the appropriate form, e.g., the form of a tread blank. The general process for producing rubber compositions and their vulcanizates is described in “Rubber Technology Handbook,” W. Hofmann, Hanser Verlag, 1994. It is known to those skilled in the art that, depending on the mixture, particularly the filler content, further mixing stages may be necessary after the first. Basic mixing stage are to be carried out in order to achieve a better reduction in viscosity and better homogenization. Tires The present invention also relates to a tire in which at least one component was produced at least partially from a rubber composition according to the invention. The tire is preferably an all-season or winter tire. In the context of the present invention, tires are understood to mean pneumatic vehicle tires and solid rubber tires, including tires for industrial and construction vehicles, truck tires, passenger cars and two-wheel tires. According to a preferred embodiment of the invention, the tire has the rubber composition according to the invention at least in the tread. The present invention further relates to a process for producing a tire, wherein one or more components of the tire are produced from the rubber composition according to the invention and the rubber composition is cured.The use of the rubber composition according to the invention can significantly improve the process for producing tires and treads. Use The present invention further relates to the use of fatty acid esters of at least one C8 to C12 group. 22 -fatty acid and a compound selected from C2 to C4 alkoxylate of a polyol, polyethylene glycol, polypropylene glycol and / or copolymer of ethylene oxide and propylene oxide as a rubber additive in a rubber composition for improving the Mooney viscosity and / or extrusion properties of the rubber composition and / or for improving at least one of abrasion, wet grip, and / or rolling resistance of a tire produced from the rubber composition. In a preferred embodiment of the use according to the invention, at least one of the stated properties is improved compared to a rubber composition which comprises a known rubber additive in an identical amount instead of the rubber additive according to the invention. Materials known in the prior art that are used as rubber additives can be used as known rubber additives. For testing, two otherwise identical rubber compositions are prepared, and their properties are subsequently compared with one another.In a preferred embodiment, at least one of the stated properties is improved by at least 5%, preferably at least 10%, compared to a rubber composition which comprises a known rubber additive in an identical amount instead of the rubber additive according to the invention. In a preferred embodiment, at least one of the stated properties is improved by at least 5%, preferably at least 10%, compared to an otherwise identical rubber composition, ie, the rubber additive according to the invention is additionally added to the rubber composition. For testing, in this case, two identical rubber compositions are produced, and the rubber additive according to the invention is additionally added to one of them. The properties of the two rubber compositions are then compared.In a preferred embodiment, at least one of the stated properties is improved by at least 5%, preferably at least 10%, compared to a rubber composition which, instead of the rubber additive according to the invention, comprises a known plasticizer in an identical amount and is otherwise identical. Known plasticizers can be com- Commercially available materials, such as Tudalen 4192, can be used. In a preferred embodiment, the extrusion properties of the rubber composition are improved compared to a rubber composition which, instead of the rubber additive according to the invention, comprises a known plasticizer in an identical amount or which does not comprise a plasticizer and is otherwise identical. Extrusion properties are understood to mean properties such as extrusion speed, injection swell, extrusion rate, material pressure, material temperature, and / or the surface / edge quality of the extrudate. In a preferred embodiment, the surface quality and / or edge quality of the extrudate is improved. The surface is rated using a grading system from AE, with A being the best grade. The edges are rated using a grading system from 1-10, with 10 being the best grade (each according to ASTM D 2230).The rubber additive according to the invention can be used in particular in a rubber composition for treads. In a preferred embodiment, the inventive use employs a mixture which contains a) one or more solid carrier materials, and b) one or more fatty acid esters, and c) optionally further constituents such as amides, amino alcohols, and / or soaps. Preferably, inorganic fillers (such as, for example, silicas) or waxy materials (such as, for example, polyethylene waxes) can be used as the carrier material. In a preferred embodiment, a silica is used as the carrier material. The weight ratio of carrier material to fatty acid ester in the mixture is, for example, 10 / 90 to 90 / 10, more preferably 20 / 80 to 80 / 20, and particularly preferably approximately 30 / 70 or 33 / 67. Working Examples The invention will now be explained in more detail using comparative and working examples, without, however, being limited to these examples. Example 1 - Preparation of the Rubber Additives According to the Invention a) Rubber Additive A 1217.8 g of ethoxylated glycerol (Aduxol GLY-07 from Schärer + Schläpfer), 835.7 g of fatty acid, and 2.0 g of hypophosphorous acid were initially introduced. The fatty acid used was an oleic acid mixture containing 72.5% C 18:1 , 8% C 18:2 , 6% C 16:1 , 4.5% C 16 , 4% C 14+14:1 , ≤ 4% C 14 , ≤ 3% C 18 , ≤ 2.5% C 18:3 and ≤ 1% C 12contains. The oleic acid mixture had an acid number of 201.0 mg KOH / g, a saponification number of 202.0 mg KOH / g and an iodine number of 100.0 g iodine / 100 g. The iodine number was determined according to DIN EN ISO 3961 2018-11 and the saponification number according to DIN EN ISO 3681. The mixture was slowly heated to 230 °C and a vacuum was applied. The course of the reaction was monitored by measuring the acid number. The fatty acid ester produced had an acid number of 4.6 mg KOH / g. From the measurement of the hydroxyl number it could be deduced that predominantly a monoester was obtained. b) Rubber additive B 592.2 g polyethylene glycol 400, 408.7 g fatty acid and 1.0 g hypophosphorous acid were initially charged. Dist. Soybean oil fatty acid is used, which contains 2 - 6 % C 18 , 20 – 29% C 18:1 , 47 – 58 % C 18:2 , 4-10% C 18:3 , 9 - 12% C 16 , 0 - 1 % C 16:1 , and 0 - 1 % C 12+14The soybean oil fatty acid used had an acid number of 194 to 204 mg KOH / g, a saponification number of 195-206 mg KOH / g, and an iodine number of 125-139 g iodine / 100 g. The mixture was slowly heated to 230 °C and a vacuum was applied. The reaction progress was monitored by measuring the acid number. The fatty acid ester produced had an acid number of 1.9 mg KOH / g. The kinematic viscosity at 20 °C of the produced fatty acid ester was 95.1 mm2 / sec, and the dynamic viscosity at 20 °C was 94.8 mPa s. b) Rubber Additive C: 352.8 g of polypropylene glycol 600, 161.8 g of soybean fatty acid (see Rubber Additive B), and 0.5 g of hypophosphorous acid were initially introduced. The mixture was slowly heated to 230 °C and a vacuum was applied. The reaction progress was monitored by measuring the acid number. The produced fatty acid ester had an acid number of 1.7 mg KOH / g.The kinematic viscosity at 20 °C of the fatty acid ester produced was 107.1 mm2 / sec. Example 2 – Preparation of a Rubber Additive According to the Invention Preparation of the Rubber Composition The mixture was prepared under conventional conditions in one or more mixing stages. It was then further processed, e.g., by extrusion, and formed into the appropriate shape. The various components of the individual mixtures are listed in the tables below. Table 1 For all compound examples included in the table, the quantities given (parts by weight) are based on 100 parts by weight of total rubber (phr). Test specimens were prepared from all compounds, and material properties typical for the rubber industry were determined using these specimens using the test methods specified below: ^ Mooney viscosity (MS 1+4, 100 °C), after each mixing stage and after aging, in each case according to DIN EN ISO 289-1, ^ Extrusion properties (extrusion speed, injection swell, extrusion rate, material pressure, material temperature) surface assessment (Garvey Die: surface AE with A as the best grade, edges 1-10 with 10 as the best grade), each according to ASTM D 2230, ^ Material pressure at various shear rates was measured with a HDK - Göttfert Rheograph 25 (measurement temperature 100°C, nozzle geometry: round, length 10 mm, diameter 1 mm).^ Rebound resilience at RT, measured according to ASTM D-8059 ^ Shore A hardness at room temperature (RT), measured according to DIN EN ISO 868, ^ Tear strength, elongation at break and tensile strength measured according to DIN 53 504, parameters for stiffness, also for tire abrasion, ^ Stress values ​​at 100 and 300% elongation at room temperature (modulus 100%, modulus 300%), according to DIN 53504, ^ Loss factor tan delta at -20 °C, 0 °C and 60 °C according to DIN 53545, o Dynamic mechanical analysis, where the vulcanized material is clamped and dynamically loaded, o Adhesion to snow is correlated with the tan delta at -20 °C (the higher the tan delta at -20 °C, the better the snow adhesion), as described in the Encyclopedia of Polymer Blends, Volume 2: Processing, edited by Avraam I.Isayev, Sanjay Palsule, o Wet grip is correlated with the tan delta at 0°C (the larger the tan delta at 0°C, the better the wet grip), o Rolling resistance is correlated with the tan delta at 60°C (the smaller the tan delta at 60°C, the lower the rolling resistance), ^ Rebound according to DIN 53512. Example 3 - Comparison against Process Oil In this example, the properties of a rubber composition containing Additive A prepared in Example 1 (Composition B) were compared with the properties of an otherwise identical rubber composition containing only TDAE oil (Composition A). The comparison shows improved processing properties, as well as improved tire handling and comparable tire grip properties, of the inventive rubber composition B. In addition, the inventive rubber composition exhibits, in particular, a lower rolling resistance, tan delta, at 60°C. The corresponding information and data are shown in Table 2 below. Table 2 Images of various extrudates of compositions A and B (after 24 hours and after one week, at 60 rpm and 15 rpm) are shown in Figures 1a-d. Figure 1a shows extrudates of compositions A and B after 24 hours at 15 rpm, Figure 1b shows extrudates of compositions A and B after 24 hours at 60 rpm, Figure 1c shows extrudates of compositions A and B after one week at 15 rpm, and Figure 1d shows extrudates of compositions A and B after one week at 60 rpm. As shown, the extrudates of rubber composition B according to the invention have significantly fewer edges and an improved surface structure in all cases. In addition, rubber composition B according to the invention has better processability (lower Mooney viscosity) and improved rolling resistance (lower tan delta at 60°C). Example 4 – Comparison with Composition Without Inventive Rubber Additive This example compares the properties of a rubber composition containing Additive A from Example 1 (Composition D) with an otherwise identical rubber composition without the additive (Composition C). Table 3 Images of various extrudates of compositions C and D after 24 hours at 60 rpm and 15 rpm are shown in Figures 2a and b. Figure 2a shows extrudates at 15 rpm and Figure 2b shows extrudates at 60 rpm. As shown, the extrudates of the rubber composition D according to the invention have an improved surface structure in both cases. In addition, the rubber composition D according to the invention has better processability (lower Mooney viscosity), improved tire handling (higher stiffness), better abrasion properties (improved ultimate tear properties and lower DIN abrasion values) and improved wet grip (higher tan delta at 0°C) with a comparable rolling resistance (tan delta at 60°C).Example 5 - Comparison with Glycerol Monooleate In this example, the properties of a rubber composition containing Additive A prepared in Example 1 (Composition E) were compared with the properties of an otherwise identical rubber composition containing glycerol monooleate instead (Composition F). The comparison shows improved processing properties, improved tire handling, and comparable to improved tire grip properties of the inventive rubber composition E. In addition, the inventive rubber composition exhibits, in particular, a lower rolling resistance, tan delta, at 60°C. The corresponding information and data are shown in Table 4 below. Images of various extrudates of compositions E and F (after 24 hours and after one week, at 60 rpm and 15 rpm) are shown in Figures 3a-d. Figure 3a shows extrudates of compositions E and F after 24 hours at 15 rpm, Figure 3b shows extrudates of compositions E and F after 24 hours at 60 rpm, Figure 3c shows extrudates of compositions E and F after one week at 15 rpm, and Figure 3d shows extrudates of compositions E and F after one week at 60 rpm. As can be seen from Figures 3a-d, the extrudates of the rubber composition B according to the invention have significantly fewer edges and an improved surface structure in all cases. In addition, the rubber composition E according to the invention has improved tire handling (higher stiffness), improved snow grip (higher tan delta at -20 °C), improved wet grip (higher tan delta at 0 °C) and improved rolling resistance (lower tan delta at 60 °C).Example 6 – Comparison of Properties of Rubber Additive AC In this example, the properties of rubber compositions containing additives A to C prepared in Example 1 (composition HJ) were compared with the properties of an otherwise identical rubber composition that instead contains more TDAE process oil (composition G). The comparison (see the data in Table 5) shows improved processing properties. Depending on the additive used, processing can be specifically improved in various process steps (e.g., during mixing or extrusion). In addition, other material properties can be specifically optimized by selecting the additive. Table 5 In general, the inventive compositions H - J exhibit improved extrusion properties (low material pressure, improved extrudates) and lower mixed viscosities. Additive C (composition J), in addition to improved processing (lower Mooney MS values ​​and material pressures), exhibits better ultimate tear properties (tensile strength, elongation at break, and tear resistance) as an indicator of better C&C (cut & chip) properties, and higher tan delta values ​​at 0°C and 20°C as an indicator of better tire grip under wet and dry conditions. Additive B (composition I) shows an even more significant improvement in processability, evident from lower material pressures, especially at high shear rates, with simultaneous improved tear resistance, without negatively affecting the conflicting objectives of wet braking (comparable tan delta at 0°C) and rolling resistance (comparable tan delta at 60°C).

Claims

Claims: A rubber composition comprising rubber and at least one rubber additive, characterized in that the at least one rubber additive comprises a fatty acid ester, which fatty acid ester is prepared from at least one C8 to C22 fatty acid and at least one compound selected from a C2 to C4 alkoxylate of a polyol, polyethylene glycol, polypropylene glycol and / or a copolymer of ethylene oxide and propylene oxide. A rubber composition according to claim 1, characterized in that the fatty acid comprises at least one saturated or unsaturated C12 to C22 fatty acid, preferably at least one C16 to C20 fatty acid or mixtures thereof, in particular at least one C8:1 fatty acid and / or C18:

2. _Fatty acid. Rubber composition according to one of the preceding claims, characterized in that the fatty acid ester is produced from at least one polyethylene glycol, polypropylene glycol and / or statistical copolymer or block copolymer of ethylene oxide and propylene oxide, wherein preferably the polyethylene glycol, polypropylene glycol and / or statistical copolymer or block copolymer of ethylene oxide and propylene oxide has a molecular weight of 200 to 800 g / mol. Rubber composition according to one of the preceding claims, characterized in that the fatty acid ester is produced from at least one polyol ethoxylate with up to 10, such as 5 to 10, e.g. 7 ethylene oxide units (EO units) and / or polyol propoxylate with up to 10, such as 5 to 10, e.g. 7 propylene oxide units (PO units) are produced, wherein the polyol ethoxylate or polyol propoxylate preferably has between 2 and 4 hydroxyl groups.Rubber composition according to claim 4, characterized in that the polyol ethoxylate is ethoxylated glycerol. is that, in particular, up to 10, such as 5 to 10, e.g., 7 ethylene oxide units (EO units) are present. A rubber composition according to one of the preceding claims, characterized in that the fatty acid ester: • an acid number (AN) of 0 to 10 mg KOH / g; and / or • a hydroxyl number (OHZ) of 5 to 190 mg KOH / g; and / or • a pour point of 5 to -50 °C; and / or • exhibits a dynamic viscosity of 50–1000 mPas. Rubber composition according to one of the preceding claims, characterized in that the composition contains between 0.1 and 40 phr of fatty acid esters, preferably 1 to 30 phr, in particular 5 to 30 phr. Rubber composition according to one of the preceding claims, characterized in that the composition comprises at least one styrene-butadiene rubber, polyisoprene rubber, natural rubber and / or butadiene rubber, and optionally their functionalized forms.A rubber composition according to any of the preceding claims, characterized in that, compared to an identical composition comprising a known rubber additive in the same quantity instead of the rubber additive according to the invention, the composition has a Mooney viscosity that is at least 5%, preferably 10%, lower and / or a material pressure during extrusion that is at least 5%, preferably 10%, lower. A rubber composition according to any of the preceding claims, characterized in that, after vulcanization, the composition has a rolling resistance (tan delta at 60°C) that is at least 5%, preferably 10%, lower and / or a wet adhesion (tan delta at 0°C) that is 5%, preferably 10%, particularly 15% higher than that of the rubber additive according to the invention. A rubber composition according to one of the preceding claims, characterized in that the composition is suitable for the production of tread compounds for tires. The use of fatty acid esters of at least one Cs to C22 fatty acid and at least one compound selected from C2 to C4 alkoxylate of a polyol, polyethylene glycol, polypropylene glycol and / or copolymer of ethylene oxide and propylene oxide as a rubber additive in a rubber composition to improve the Mooney viscosity and / or the extrusion properties of the rubber composition and / or to improve at least one of the abrasion, wet grip and / or rolling resistance properties of a tire produced from the rubber composition.Use according to claim 12, wherein at least one of the aforementioned properties is improved by at least 5%, preferably at least 10%, compared to a rubber composition comprising a known rubber additive in an identical quantity instead of the rubber additive according to the invention. Use according to claim 12 or claim 13, characterized in that the fatty acid ester is as defined in any one of claims 1 to 6 and / or that the rubber composition is as defined in any one of claims 7 to 11. Use according to any one of claims 12 to 14, characterized in that a mixture is used which contains a) one or more solid carrier material(s), wherein silica is preferably used as the carrier material, b) one or more of the fatty acid esters, and c) optionally further components such as amides, amino alcohols, and / or soaps.Method for manufacturing a tire, characterized in that one or more components of the tire are made of a rubber composition according to one of claims 1 to 11 and the rubber composition is cured. Tire in which at least one component is at least partially made from a rubber composition according to one of claims 1 to 11, and the tire is preferably an all-season or winter tire, wherein the component is in particular a tread.

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