SK7977Y1 - Rubber compositions and their use - Google Patents

Abstract

There are described a rubber compositions containing at least one rubber, triacetin and at least one filler selected from the group of cellulose and / or cellulose derivatives. The compositions are suitable for the production of vulcanizates and / or shaped articles, e.g. as fill a golf balls.

Description

The present utility model relates to novel rubber compositions comprising cellulose and / or cellulose and triacetin derivatives, their use for the manufacture of rubber vulcanizates and rubber vulcanizates made therefrom, as well as a novel rubber additive.

BACKGROUND OF THE INVENTION

The rolling resistance of passenger car tires increases fuel consumption by 20 to 25 percent, and for trucks by up to about 30 percent. These values have prompted the European Commission to issue a regulation on the mandatory use of low rolling resistance tires for the automotive industry. For new cars, this obligation came into force in 2011. However, much of the market is made up of tires that will be used to replace the old and used ones. Since 2012, these have to be labeled with regard to their fuel efficiency, moisture resistance and rolling noise (driving noise). A system of classifications from A (best performance) to G (worst performance), similar to the already established system for classifying household appliances, is intended to provide consumers with greater clarity and essential assistance in purchasing new tires.

Since the European Union has been addressing the limit values for carbon dioxide in the flue gases of passenger cars, car manufacturers have been looking for economic options to achieve a CO ₂ emission value of 130 g / km or less. They are largely concerned with the development of low rolling resistance tires, which do less work to change shape while driving, resulting in reduced fuel consumption. The harder the tire tread adheres to the road surface, the greater the energy loss due to abrasion and shape change. Consequently, the rubber compound intended for the tire tread must not be too soft.

At the same time, the requirements for moisture resistance and noise during driving were set so that the rolling resistance reduction would not have a negative effect on other important characteristics. The first indication of shear retention capability on wet and rolling surfaces resists tan δ loss coefficient. At 0 ° C it should preferably have a high value (good skid retention on wet surfaces), at 60 to 70 ° C as low as possible (reduced rolling resistance).

There is, therefore, a great demand for improved rubber compositions which, when introduced into tire manufacturing, result in products with better properties, lower rolling resistance and noise and better adhesion on wet surfaces.

It is known that reinforcing fillers are added to the rubber compositions during the preparation to improve these properties. These may be carbon black, silicic acid, cellulose, or layered silicates.

Strengthening of elastomeric materials is generally understood as extending the service life, improving mechanical properties such as strength, abrasion resistance or rolling resistance, but also improving dynamic properties based on the interaction of the polymer network and the filler.

While these reinforcing fillers can often improve the properties of the product, they often have a negative effect on the processability of the rubber composition. For this reason, it is common to add to the rubber composition in addition to reinforcing reinforcing fillers also auxiliaries which are intended to improve the processability of the rubber composition. Thus, for example, fatty acid esters, fatty acid salts or softening oils may be used to improve the flowability of the rubber compositions. While these additives advantageously reduce the flowability of the rubber compositions (low Mooney viscosity), at the same time they increase the stress values at high extensibility (e.g. from 100% to 300%), respectively. the disadvantage is that they reduce the hardness of the vulcanizate, whereby the reinforcing effect of the filler fails on losses. However, too low a hardness or inflexibility of the vulcanizate will again adversely affect the properties of the product. If tires are made from vulcanizate of too low a hardness, the driving characteristics, especially in curves, will be unsatisfactory. Increasing the dosage of the reinforcing filler results in an increase in the hardness of the vulcanizate, but at the same time an increase in the viscosity of the mixture, which in turn adversely affects the processability of the vulcanizate. The same applies to the removal of the softening oil addition.

The addition of silicic acid as a filler has proven successful in the manufacture of vulcanizates intended for passenger car tire treads. Silicic acid contributes to a good combination of properties, rolling resistance, slip retention ability on wet surfaces and friction wear.

In order to achieve the desired combination of properties, it is important that the silicic acid is well dispersed in the rubber preparation process and optimally bonded to the rubber network during vulcanization. It is known in the art that organic sulfur-containing silanes (e.g. B.DE-A 24 47 614) or certain polysulftdic silanes (e.g. EP-A1 0 0670 347 and US-A) are added to the rubber mixtures as reinforcing agents. -4,709,065). However, in the case of polysulfide silanes, relatively large amounts of these expensive additives are required to achieve acceptable processability.

It is already known from EP-A 1728821 that short fibers, e.g. 0.1-12 mm cellulose fibers. Various plasticizers with a molecule have been used to improve fiber dispersion

EN 7977 Υ1 with a mass greater than 400 g / mol.

EP-A 2072574 discloses a rubber structure with sulfur in a network that contains a chemically modified, e.g. acetylated, microfibrous cellulose. This vulcanized rubber structure can be used to manufacture tires. According to EP-A 2072574, the addition of 1 to 50 parts by weight of acetylated cellulose relative to rubber resulted in a 6% increase in tan δ. One skilled in the art is to understand the deterioration of the rolling resistance, i.e. according to this document, when cellulose and its derivatives are used as a filler in rubber compositions, and if these compositions are used in the manufacture of tires, the result would be a deterioration of the rolling resistance.

It is well known that rubber compositions may contain plasticizers. They interact with the rubber and lead to greater mobility of the chain segments, possibly to dissolution / release of crystalline ranges / regions. They cause the stress value, the hardness to decrease and the elasticity and the cold resistance to increase. There are oil softeners such as e.g. paraffinic, naphthenic and aromatic as well as synthetic emollients which can be classified as aliphatic and aromatic esters, polyesters, phosphates, ethers and thioethers. Typical ester-based plasticizers are o. i. violet acid esters, aliphatic esters, phosphoric acid esters, adipic acid, trimellitic acid, citric acid esters, glycol esters.

The use of triacetin as a cellulose acetate plasticizer is described in GB 317443.

The essence of the technical solution

The object of the present utility model was to provide improved methods for preparing filler-containing rubber having good technical-processing properties, from which vulcanizates and the outer surfaces of the tires produced therefrom demonstrate reduced rolling resistance.

New rubber compositions have been found including cellulose and / or cellulose derivatives as filler and triacetin as plasticizer.

Surprisingly, the new rubber compositions have longer vulcanization jump times in combination with shorter vulcanization times, thus providing better workability, without adversely affecting properties (hardness, elongation at break, tensile strength, friction wear) of vulcanizates, were made on their basis. Surprisingly, the vulcanizates produced from the new rubber compositions also have a better surface quality, which results in, for example, a better rolling resistance of the outer surface of the automobile tires thus produced.

In addition to expanding the range of technical applications, economic and environmental aspects are also playing an increasingly important role. Not only the rising prices of raw materials, but also the increased sensitivity of modern society to the environmental aspects of production, consumption and material removal are motivating industry to develop production processes with respect to raw material consumption and to bring products that are both environmentally and consumer friendly.

In this regard, there is a further advantage of the rubber compositions according to the present utility model in that the cellulose and triacetin contained therein can be obtained from renewable raw material sources. Triacetin is produced from plant derived glycerin; cellulose from vegetable fibers.

The subject of the present utility is rubber compositions comprising at least one rubber, triacetin and at least one filler of the cellulose and / or cellulose derivatives series.

In the literature, the ratio of the other components to the rubber component in the rubber compounding compositions is normally given in relative quantity phr " parts per hundred parts rubber ". This quantity marking is also given in the following.

The rubber compositions according to the present utility model generally comprise 0.1 to 100 phr of at least one cellulose and / or cellulose derivative, preferably 0.2 to 50 phr, in particular 0.3 to 30 phr.

The rubber compositions according to the present utility model generally comprise 0.1 to 80 phr of triacetin, preferably 0.2 to 60 phr, and particularly preferably 0.5 to 45 phr, especially 5-30 phr.

rubber

Compositions for preparing the rubber of the present utility model include at least one rubber. Preference is given to diene-based rubbers, in particular double-bonded rubbers, which contain practically no gel content and which are referred to as R-rubbers according to DIN / ISO 1629. These rubbers have double bonds on the backbone. For example, these rubber components are preferably used

NR: natural rubber

SBR: styrene / butadiene rubber

BR; polybutadiene rubber

IR: polyisoprene

SIBR: styrene / isoprene rubber

NBR: nitrile rubber

SK 7977 Υ1

IIR: butyl rubber (isobutene / isoprene rubber)

HNBR: hydrogenated nitrile rubber SNBR: styrene / butadiene / acrylonitrile rubber

CR: polychloroprene

XSBR: carboxylated styrene / butadiene rubber

XNBR: carboxylated butadiene-acrylonitrile rubber

ENR: epoxidized natural rubber

ESBR: epoxidized styrene-butadiene rubber and mixtures thereof.

According to the present utility model, rubbers containing double bonds are those which, according to DIN / ISO 1629, are M-rubbers and, in addition to the saturated backbone, have double bonds on the side chains. These include, for example, EPDM.

According to the present utility model, the rubbers are NR, BR, SBR, IIR and EPDM.

Particular preference is given to NR, BR, styrene-diolefin rubbers and mixtures of these rubbers.

Among styrene-diolithic (especially butadiene) rubbers, there are also abbreviated soluble SBR rubbers (or "solution rubbers"), abbreviated as: L-SBR, and emulsion SBR rubbers, for short: E-SBR. L-SBR refers to rubbery polymers which are produced by a dissolution process based on vinylaromates and conjugated dienes. Suitable vinylaromatic monomers are styrene, o-, m- and p-methylstyrene, technical mixtures of methylstyrenes, p-tert-butylstyrene, p-methoxystyrene, vinylnaphthalene, divinylbenzene, trivinylbenzene and divinylnthalene. Styrene is preferred. The content of the polymerized vinylaromate is preferably 5 to 50 wt. %, more preferably 10 to 40 wt. %. Suitable diolefins are 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, 1-phenyl-1,3-butadiene and 1,3-hexadiene. Preferably 1,3-butadiene and isoprene. The content of polymerized dienes is generally 50 to 95 wt. %, preferably 60 to 90 wt. %. The vinyl content of the polymerized diene is generally 10 to 90%, the 1,4-trans double bond content is 20 to 80%, and the 1,4-cis double bond content is complementary to the sum of the vinyl and double bond configurations 1. , 4-trans. The vinyl content of L-SBR is> 20%.

Polymerized monomers and dienes of various configurations are usually represented statistically in polymers. Also, rubbers with a block-formed structure, referred to as integral rubber, fall within the definition of L-SBR (A). L-SBR can be understood to include both linear and branched or end-modified rubbers.

The solution polymerized rubbers based on vinyl aromatics / diolefins are preferably characterized by Mooney values of from 20 to 150 Mooney units (ME), preferably in the range of 30 to 100 ME.

Particularly high molecular weight E-SBR species with Mooney values > 80 ME may contain oils in amounts of from 30 to 100 parts by weight relative to 100 parts by weight of rubber. Oil-free L-SBR rubbers have glass transition temperatures in the range of -80 to +20 ° C, as determined by DSC.

E-SBR refers to rubbery polymers which are produced in an emulsion process based on vinylaromates, conjugated dienes and optionally other monomers. Vinylaromates are styrene, p-methylstyrene and .alpha.-methylstyrene, the dienes in particular butadiene and isoprene. Among the monomers, it is in particular acrylonitrile. The vinyl aromatic contents range from 10 to 60 wt. %, glass transition temperature from -50 to +20 ° C (determined by DSC) and Mooney values between 20 and 150 ME. In particular, high molecular weight E-SBR species having Mooney values > 80 ME may contain oils in amounts of from 30 to 100 parts by weight relative to 100 parts by weight of rubber. Oil-free L-SBR rubbers have glass transition temperatures in the range of -80 to +20 ° C, as determined by differential thermal analysis (DSC).

In particular, polybutadiene (BR) comprises two different types of polybutadiene types. In the first class, 1,4-cis dienes are at least 90% and are produced by the action of Ziegler-Natta transition metal catalysts. Catalyst systems based on titanium (Ti), nickel (Ni), cobalt (Co) and neodymium (Nd) are preferably used. The glass transition temperature of this polybutadiene is preferably < -90 ° C (determined by DSC).

The second class of polybutadienes is produced with the participation of lithium (Li) catalysts and the vinyl content is in the range of 10 to 80%. The glass transition temperatures of these polybutadiene rubbers range from -90 to +20 ° C (determined by DSC).

According to the present utility model, the rubbers are preferably selected from the group of styrene / butadiene rubbers and polybutadiene, which rubbers can also be adjusted with petroleum oils.

Cellulose and cellulose derivatives

The preparation of the rubber composition of the present utility model comprises at least one cellulose and / or one cellulose derivative. The cellulose used is preferably commercial fibrous cellulose or powdered or pulverulent, respectively. in the form of tablets (CAS-Nr.:9004-34-6). Suitable cellulose derivatives are, in particular, the following products of the reaction of cellulose with phenyl isocyanate, n-butyric anhydride, acetic anhydride, butyl isocyanate, stearyl chloride, stearyl isocyanate, butyric acid chloride. Preferred are cellulose derivatives resulting from the transesterification of cellulose with organic acids (carboxylic acids4).

SK 7977 Yl mi), e.g. with acetic acid. Of particular preference among cellulose derivatives is cellulose acetate (CAS-Nr .: 9004-35-7). Cellulose can be used alone or in any mixture with said cellulose derivatives. It is preferred to use cellulose acetate alone.

triacetin

The preparation of the rubber composition according to the present utility model comprises at least one triacetin. Triacetin is also known as glycerol triacetate or 1,2,3-propanetriol triacetate (CAS-Nr .: 102-76-1, commercial product of Lanxess Deutschland GmbH).

ingredients

The preparation of the rubber compositions according to the present utility model may optionally contain other additives. Examples of suitable fillers, crosslinking systems, sulfur-based vulcanization accelerators, plasticizers, compounds that improve the technical processability of the compositions, anti-aging, UV and ozone protective agents, as well as other additives such as tackifiers, pigments, dyes, blowing agents, adhesion enhancers and adhesives and reversals.

The amount of additives used in the preparation of the rubber compositions according to the present utility model can vary considerably. Generally, the preparation of the rubber according to the present utility model comprises 0.1 to 100 phr, preferably 0.1 to 95 phr and particularly preferably 0.1 to 90 phr of one or more additives.

fillers

There are several options for classifying fillers. It is expedient to divide according to the interaction with rubber, into reinforcing (active) and inactive fillers.

Inactive fillers:

Other suitable fillers in the sense of the present utility model are in particular carbon black, in particular ldquor; carbon black ”, which are preferably produced in gas black, furnace black, lamp black and thermal black processes and are designated according to the new ASTM nomenclature (ASTM D 1765 and D 2516) as N 110, N 115, N 121, N 125 , N 212, N 220, N 231, N 234, N 242, N 293, N 299, S 315, N 326, N 330, N 332, N 339, N 343, N 347, N 351, N 375, N 472, N 539, N 550, N 582, N 630, N 642, N 650, N 660, N 683, N 754, N 762, N 765, N 772, N 774, N 787, N 907, N 908, N 990, N 991, S 3, etc. The soot used in accordance with the present utility model has a specific surface area determined by the BET method of preferably from 5 to 200 m ² / g.

In the preparation of the rubber compositions according to the present utility model, carbon black may be used in amounts of 0 to 120 phr, preferably in the range of 1 to 100 phr, particularly preferably in the range of 5 to 80 phr.

If the process for the preparation of the rubber according to the present utility model includes carbon black, the total amount of oxygen-containing filler containing hydroxyl groups and carbon black is preferably in the range of 20 to 160 phr, preferably 25 to 140 phr.

Other fillers that may be used include:

- synthetic silicates, e.g. aluminum silicate, alkaline earth element silicates, such as magnesium or calcium silicate having a BET specific surface area of 20 to 400 m ² / gas with a primary particle diameter of 5 to 400 nm,

- natural silicates, e.g. kaolin and other naturally occurring silicas,

- metal oxides, e.g. zinc oxide, calcium oxide, magnesium oxide, aluminum oxide,

- metal carbonates, e.g. calcium, magnesium, zinc carbonate,

- sulphates of metal, e.g. calcium sulfate, barium sulfate,

- metal hydroxides, e.g. aluminum and magnesium hydroxide,

- glass fibers and glass fiber products (plates, cords or glass microspheres).

Active fillers:

The rubber composition compositions of the present utility model preferably comprise at least one additional filler of the series of oxygen-containing hydroxyl-containing fillers. In the category of oxygen-containing oxygen-containing fillers, it is preferable to use a hydroxyl-containing filler and silicon, particularly preferably silicic acid. In hydrophilic silicas, hydroxyl groups are particularly on the surface.

For the purposes of the present utility model, silicic acid or silicic acid is used in particular as pyrogenic silicic acid or as silicic acid with reduced activity, preferably silicic acid with reduced activity. The specific surface area for reduced activity silicas is 5 to 1000 m ² / g according to BET, preferably 20 to 400 m ² / g. They are prepared from water glass and inorganic acids, with sulfuric acid being preferred. The silicas may also be present as a mixture of oxides with other metal oxides, e.g. with oxides of aluminum, magnesium, calcium,

Y 79 barium, zinc, zirconium, titanium.

According to the present utility model, silicas with a specific surface area of 5 to 1000 m ² / g, particularly preferably 20 to 400 m ² / g, determined according to BET, are preferably used.

Generally, the rubber composition compositions of the present utility include 5 to 100 phr of at least one hydroxyl group-containing oxygen filler, preferably 30 to 100 phr and particularly preferably 50 to 90 phr, wherein the hydroxyl-group oxygen-containing filler is preferably at least 30%, but especially at least 50% based on the total amount of fillers used.

The silicic acid surface can also be modified with silanes. Such a chemical reaction can be performed with all fillers having silanol groups on the surface. The silanol groups react relatively easily with silanes to form organic siloxanes. Modification of OH groups with silanes (mono- and bifunctional organic silanes) improves the interaction with non-polar rubbers.

Silanes (usable) for surface modification of silicas

Compositions for preparing rubber in accordance with the present utility model may include one or more mono- and bifunctional organic silanes. Suitable silanes are, in particular, sulfur-containing organic silicon compounds. Particular preference is given to those sulfur-containing organic silicon compounds which contain one or more alkoxy-silyl groups, in particular one or more trialkoxysilyl groups.

Particularly particularly preferred sulfur-containing organic silicon compounds are bis (tri-ethoxy-silyl-propyl-polysulfan; these products are, for example, under the trade names Silan Si 75 and Silan Si 69 (CAS-Nr .: 40372-72-3) available from the company Degussa.

Organic silicon compounds containing sulfur in an amount of 0.1 to 14 phr, in particular in an amount of 0.2 to 12, may be used in the rubber composition compositions of the present utility model.

In the case where the rubber compositions according to the present utility model comprise an oxygen-containing hydroxyl-containing filler, it is preferred to use at least one silane which ensures the bonding of the hydroxyl-containing oxygen-containing filler to the rubber network. These silanes are also referred to as enhancing additives. They are particularly suitable from the series of organic sulfur-containing silicon compounds. By way of example, bifunctional organosilanes with netting groups - vinyl or thio - may be mentioned. Preferably, at least one bis (triethoxysilyl-propyl) -tetrasulfide or bis (triethoxysilylpropyl) -disulfide has been used as the reinforcing additive for oxygen-containing hydroxyl-containing fillers in the preparation of the rubber according to the present utility model.

Network forming system

Compositions for preparing rubber in accordance with the present utility model may include one or more mesh forming systems. It is particularly preferred to use sulfur or sulfur donors, for example dithiomorpholine (DTDM) or 2- (4-morpholine-dithio) benzothiazole (MBSS). Sulfur and sulfur donors may be used in amounts of 0.1 to 15 phr, preferably 0.1 to 10 phr. Network forming systems may be used alone or in combination with vulcanization accelerators.

Vulcanization accelerators

Suitable vulcanization accelerators are, for example, mercaptobenzothiazole, sulfenamide, guanidine, thiuram disulfide, dithiocarbamates, thioureas, thiocarbonates as well as dithiophosphates and the like.

The vulcanization accelerators may be used in amounts of 0.1 to 15 phr, preferably 0.1 to 10 phr.

Compositions for the preparation of rubber within the meaning of the present utility model include at least one vulcanization accelerator. Alternatively, several accelerators may be used in combination with conventional activators.

Reversing preparations

Compositions for the preparation of rubber within the meaning of the present utility model may comprise one or more reversible agents, e.g. 1,6-bis- (N, N-dibenzylthiocarbamoyldithio) hexane (CAS-Nr .: 151900-44-6), 1,3-bis (3-methyl-2,5-dioxopyrrol-1-yl) methyl ) benzene (CAS-Nr .: 119462-56-5) or hexamethylene-1,6-bis (thiosulfate) disodium dihydrate (CAS-Nr .: 5719-73-3). Particular preference is given to using 1,6-bis- (N, N-dibenzylthiocarbamoylditio) hexane. Said reversal agents may be used individually or in any mixture with each other: preferably in amounts of 0.1 to 20 phr relative to the rubber.

Aging protective equipment

In preparing the rubber composition of the present utility model, it is desirable to add one or more anti-aging agents, i. j. substances inhibiting the effect of heat and oxygen. Suitable are e.g. phenol-derived substances, alkylated phenols, styrene phenol, phenols with spherical barriers such as e.g. 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-p-cresol (BHT), 2,6-di-tert-butyl-4-ethylphenol, spherical barrier phenols containing ester functional groups, phenol with spherical impediments containing thioether functional groups, 2,2-methylene-bis- (4-methyl-6-tert-butylphenol) (BPH) as well as thiobisphenols with steric impediments.

SK 7977 Yl

If the coloring of the rubber is not implied, amine-based anti-aging agents, e.g. mixtures of diaryl-β-phenylenediamines (DTPD), octylated diphenylamine (ODPA), phenyl-α-naphthylamine (PAN), phenyl-3-naphthylamine (PBN), in particular phenylenediamine-based compounds. For example, N-isopropyl-N'-phenyl-p-phenylenediamine, N1,3-dimethylbutyl-N'-phenyl-p-phenylenediamine (6PPD), N1,4-dimethylpentyl-N'-phenyl-p-phenylenediamine (7PPD), N, N'-bis-1,4- (1,4-dimethylpentyl) -β-phenylenediamine (77PD).

Other anti-aging agents include phosphoric acid derivatives, e.g. tris- (nonylphenyl) phosphite, polymerized 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ), 2-mercaptobenzimidazole (MBI), zinc methylmercaptobenzimidazole (ZMMBI) Phosphites are commonly used in combination with phenolic anti-aging agents. Peroxide vulcanized rubbers have been used TMQ, MBI and MMBI, and the anti-aging agents can be added to the rubber compositions in the usual amounts, for example 0.1 to 5 phr, in accordance with the present utility model.

antioxidants

The ozone resistance of the rubber prepared according to the present utility model can be increased by known antioxidants, e.g. N 1, 3-dimethylbutyl-N'-phenyl-p-phenylenediamine (6PPD), N 1, 4-dimethylpentyl-N'-phenyl-p-phenylenediamine (7PPD), N, N'-bis-1,4- (1, 4-dimethylpentyl) 4-dimethylpentyl) -p-phenylenediamine (77PD), enol ether or cyclic acetals. The antioxidants may be added to the rubber compositions prepared in accordance with the present utility model in amounts usually e.g. 0.1 to 5 phr.

emollients

The rubber compositions of the present utility model may include conventional plasticizers such as petroleum oil and / or synthetic esters, for example, esters of violet acids, adipic, phosphoric, citric, benzoic, trimellitic or acetic acid. Amounts of 0.11 to 80 phr, preferably 0.2 to 60 phr, in particular 0.5 to 45 phr, were used.

Preparations improving the workability of rubber mixtures

The rubber composition of the present utility may also contain other conventional formulations improving processability. These additives should be active between the rubber particles and counteract the frictional forces during mixing, plasticizing and shaping. The rubber composition prepared in accordance with the present utility model may contain all conventional plasticizers suitable for processing plastics in the usual amounts.

Other additives

Alternatively, other additives may be used in the preparation of the rubber composition of the present utility model, e.g. flame retardants, blowing agents, antistatic agents, biocides, petroleum oils, surface adhesion enhancers, dyes, pigments, waxes, resins, bulking agents, organic acids, vulcanization retardants, vulcanization activators, e.g. zinc oxide, stearic acid as well as zinc stearate, metal oxides, as well as other filler activators such as e.g. triethanolamine, trimethylolpropane, polyethylene glycol, hexanetriol, aliphatic trialkoxysilanes or others known in the rubber industry. They are commonly used in amounts of 1 to 50 phr.

Plastic materials

Other plastics may also be included in the rubber composition according to the present utility, which act, for example, as polymer processing aids or as impact improvers. These plastics are from the group of homo- and copolymers based on ethylene, propylene, butadiene, styrene, vinyl acetate, vinyl chloride, glycidyl acrylate, glycidyl methacrylate, acrylates and methacrylates with a branched or unbranched C 1 -C 10 -alcohol alcohols. Particular mention may be made of polyacrylates with the same or different alcohol substituents from the group C ₄ to C ₈ -alcohols, in particular butanol, hexanol, octanol and 2-ethylhexanol, polymethyl methacrylate, methyl methacrylate-butyl acrylate copolymers, methyl methacrylate copolymer, ethyl methacrylate copolymer, chlorinated polyethylene, copolymers of ethylene with propylene, copolymers of ethylene, propylene and dienes.

Multiple ingredients in any combination may be included.

Preference is given to a rubber composition comprising at least one rubber, 0.2 to 50 phr of cellulose and / or cellulose acetate, 0.2 to 60 phr of triacetin and 0 to 10 phr of at least one sulfur-based acceleration system and 0 to 95 phr of at least one additional additives.

Particularly preferred are rubber compositions comprising at least one rubber of the synthetic rubber series, 0.3 to 30 phr cellulose and / or 0.3 to 30 phr cellulose acetate, and 0.5 to 45 phr triacetin, 0 to 10 phr of at least one accelerator. a sulfur-based system of a series of sulfur / sulfenamide systems and 50 to 90 phr of at least one oxygen-containing hydroxyl group filler and 0.2 to 12 phr of at least one silane

From a series of sulfur-containing organic silicon compounds.

Particularly preferred are rubber compositions comprising at least one of the styrene-butadiene polybutadiene rubber series, 0.3 to 30 phr cellulose and / or 0.3 to 30 phr cellulose acetate and 0.5 to 45 triacetin, 0 to 10 phr of at least one accelerator. a sulfur-based system of a series of sulfur / sulfenamide systems, 50 to 90 phr of silicic acid having a specific surface area of 5 to 1000 m ² / g as determined by the BET method and 0.2 to 12 phr of at least one crosslinker from bis (triethoxysilylpropyl) -tetrasulfide and bis (triethoxy-silylpropyl) disulfide.

The preparation of the rubber according to the present utility model can be carried out by a known process in which, for example, the individual components and, if appropriate, other additives are mixed with one another. Mixing is conveniently carried out in a non-continuous mixing process (on mixers and rollers) at a temperature of e.g. 80-150 ° C.

The cellulose and / or cellulose derivative and triacetin rubber components may be added individually or as a mixture in any mixing ratio and at each mixing stage during the mixing process.

Of the rubber compositions according to the present utility, they can be subsequently used in a mixing apparatus at a temperature of e.g. 150 to 200 ° C, preferably at 130 to 180 ° C and optionally under a pressure of 1 to 100 bar, to produce rubber vulcanizates.

A further object of the utility model is to use a composition comprising at least one cellulose and / or a cellulose and triacetin derivative as a rubber additive.

The compositions useful according to the utility model comprise at least one cellulose and / or a cellulose derivative. Fiber cellulose (pure cellulose description, CAS-Nr .: 9004-34-6) was used. Suitable cellulose derivatives are, in particular, the following products of the reaction of cellulose with phenyl isocyanate, n-butyric anhydride, acetic anhydride, butyl isocyanate, stearyl chloride, stearyl isocyanate or butyric acid chloride.

Preference is given to cellulose derivatives which are obtained by esterifying cellulose with organic, carbonic acids, e.g. with acetic acid. Cellulose acetate (CAS-No .: 9004-35-7) is particularly preferred. Cellulose alone or in any mixture with said cellulose derivatives may be used.

The most useful utility according to the utility model is a mixture of cellulose acetate and triacetin.

The composition useful in the utility model generally comprises 99 parts by weight to 1 part by weight of at least one cellulose and / or cellulose derivative and 1 to 99 parts by weight of triacetin, preferably a mixture consisting of 60 to 2 parts by weight of at least one cellulose and / or cellulose derivative and 40 to 40 parts. 98 parts by weight of triacetin, particularly preferably mixtures comprising 50 to 3 parts by weight of cellulose and / or cellulose derivative and 50 to 97 parts by weight of triacetin, particularly preferably 40 to 4 parts by weight of cellulose and / or cellulose derivative and 60 to 96 parts by weight of triacetin.

The utility model can be a suitable rubber additive. Suitable rubbers are those which are listed as being conventional and preferred and mixtures thereof. The addition of the inventive compositions useful as rubber additives can improve the technical processability during the rubber preparation. In particular, the addition prolonged the time of vulcanization, while reducing the duration of vulcanization, without adversely affecting the properties of the rubber vulcanizate thus produced (such as hardness, extensibility or elongation at break, tensile strength, friction wear).

The rubber vulcanizates are produced in a multi-stage blending process, wherein at least one cellulose and / or cellulose derivative and triacetin and at least one rubber are mixed in amounts indicated for these components in general or preferentially, optionally in the presence of one or more additives, e.g. other fillers, anti-aging agents, anti-aging agents, antioxidants, plasticizers, and aids to facilitate processing at temperatures of 80-150 ° C in a mixing apparatus, e.g. in a mixer, roller and / or extruder, and vulcanized in the presence of at least one mesh forming system and / or vulcanization accelerator at a temperature of 150 ° C to 250 ° C, preferably 130 to 180 ° C, optionally under a pressure of 1 to 100 bar.

Filled rubber vulcanizates are produced by mixing at a temperature of 80 to 150 ° C in a mixing apparatus, e.g. mix in at least one rubber, at least one cellulose and / or cellulose derivative and triacetin, at least one hydroxyl group-containing oxygen filler and at least one mono- or bifunctional organic silane in the amounts specified for these components in a mixer, roller and / or extruder in a multi-stage mixing process in general or preferentially, optionally in the presence of one or more additives, e.g. other fillers, anti-aging agents, anti-aging agents, antioxidants, emollients and processability improvers, and vulcanizes in the presence of at least one network-forming system and / or vulcanizer at a temperature of 150 ° C to 250 ° C, preferably 130 to 180 ° C, optionally at a pressure of 1 to 100 bar.

In the manufacture of rubber vulcanizates according to the present utility model, it is preferable to include sulfur in the network with said network forming systems.

According to the present utility model, the rubber additives and possibly other additives are added, in particular in the first part of the mixing process, at a batch temperature of 100 to 200 ° C, but it is possible to add 8

SK 7977 Υ1 at lower temperatures (20 ° C to 100 ° C), eg. together with a sulfur-based netting additive and / or accelerator. Utility model additives can be added directly as a mixture consisting of cellulose and / or cellulose derivative and triacetin or as individual components.

The crosslinking additive and / or the vulcanization accelerator is expediently not added in one mixing step at elevated temperatures, when it activates an oxygen-containing filler containing hydroxyl groups (e.g. silicic acid) by the action of organic sulfur-containing silicon compounds, as this would lead to premature vulcanization mixture. The crosslinking additive and / or vulcanization accelerator are therefore preferably worked after addition of sulfur-containing organic silicon compounds, preferably at temperatures below 100 ° C.

The production of rubber vulcanizates according to the present utility model can be carried out, for example, in the following mixing stages:

Stage 1 mixing:

Put rubber (e.g. a mixture of SBR and BR) into the mixer and allow to stir for about 30 seconds.

Respectively. add an hydroxyl group-containing oxygen filler and a silane to modify the surface area (e.g., two-thirds of silicic acid, two-thirds of silane, allowed to mix for about 60 seconds, and a third of silicic acid, one-third of silane added, about 60 seconds).

A mixture of cellulose acetate and triacetin is added. carbon black, oil, anti-aging agent, zinc oxide as well as ozone-protecting waxes; the mixture is allowed to stir for about 60 seconds.

This mixing process can be carried out at temperatures of 20 to 200 ° C, preferably around 150 ° C.

2nd mixing stage:

Upon completion of the first stage of mixing, the mixture is transferred to an attached roller where it is formed into a plate, strip or tablet and stored at room temperature for 24 hours.

The processing temperatures do not exceed 60 ° C.

3rd degree of mixing:

In the third mixing step, at a temperature of 140 to 170 ° C, preferably at 150 ° C, additional cleavage, e.g. in a mixer / batch mixer.

4th degree of mixing:

Addition of additives such as vulcanization accelerators and / or sulfur-containing netting additives, preferably on a roller at low temperatures (<80 ° C).

Aggregates suitable for the production of mixtures are known and include, for example, rollers, batch mixers or even mixing extruders.

A further object of the present utility model is the use of a rubber composition according to the utility model for the manufacture of rubber vulcanizates, in particular filled rubber vulcanizates and molded rubber articles, in particular tires and prefabricated tire products.

A further object of the present utility model is rubber vulcanizates and molded articles of rubber which can be produced by vulcanization in a manner known from the preparation of rubber compositions in the sense of the present utility model.

The rubber vulcanizates produced are suitable for the production of various tire precast products, in particular tire treads, lower part of protectors, tire casing skeletons, sidewalls, reinforced sidewalls of coasting tires, apex mixtures, etc., as well as the production of technical rubber products, e.g. shock absorber elements, roller / rolling machine linings, transporters, belts, spindles, gaskets, golf ball pads, shoe soles, etc. The mixtures are particularly suitable for the production of tire treads, protector lower parts, tire casings and apex mixtures. Tires resp. the tire parts also include, for example, the treads of summer, winter and all-year tires, as well as passenger and truck tires.

EXAMPLES

In the following, the utility model is explained in the examples, but is not limited thereto. Components of rubber preparation according to the presented utility model:

(1) Buna® VSL 5025-1 from Lanxess Deutschland GmbH (2) Buna® CB 24 from Lanxess Deutschland GmbH (3) Vulkasil S from Lanxess Deutschland GmbH (4) Tudalen 1849-1 (5) Zinc Beloba Red Seal (Zinkweiss Rotsiegel ) from Grillo Zinkoxid GmbH

SK 7977 Υ1 (6) Edenor C 18 98-100 from Cognis Deutschland GmbH (7) 2,2,4-trimethylM, 2-dihydroquinoline, polymerized (Vulkanox® HS / LG from Lanxess Deutschland GmbH) (8) Nl, 3 -dimethylbutyl-N'-phenyl-p-phenylenediamine (Vulkanox® 4020 / LG from Lanxess Deutschland GmbH) (9) Antilux® 654 from RheinChemie GmbH (10) bis (triethoxysilylpropyl) polysulfide (Si 69 from Degussa Huls AG) (11) Corax N 339 from Degussa Húls AG (12) Soluble sulfur (ground sulfur 90/95 ° Chancel® from Solvay Barium Strontium) (13) N-Cyclohexyl-2-benzothiazylsulfenamide (Vulkacit® CZ from Lanxess Deutschland GmbH) (14) Diphenylguanidine ( Vulkacit® D / C from Lanxess Deutschland GmbH) (15) Cellulose acetate (CAS-Nr .: 9004-35-7) 4 weight percent, from Eastman, and 96 weight percent triacetin (CAS-Nr .: 102-76- 1) from Lanxess Deutschland GmbH

Production of rubber vulcanizates according to the present utility model

The vulcanizates were made according to the rubber recipes relating to Examples 1 and 2 as well as the reference example shown in Table 1. As shown below, the respective ingredients were mixed in a multi-stage mixing process (Examples 1 and 2 as well as a reference example) , and the mixtures were then cured at 170 ° C.

Stage 1 mixing:

The mixer charge (BUNA® CB 24 and BUNA® VSL 5025-1) was allowed to stir for about 30 seconds.

Add two thirds of VULKASIL® S, two thirds of SI® 69, stirring for about 60 seconds.

Add one third of VULKASIL® S, one third of SI® 69 as well as TUDALEN® 1849-1, stirring for about 60 seconds.

Addition of CORAX® N 339, EDENOR® C 18 98-100, a mixture of cellulose acetate with triacetin, VULKANOX® 4020 / LG, VULKANOX® HS / LG, zinc white Red Seal as well as ANTILUX® 654, mixing for about 60 seconds.

This stirring process was carried out at 150 ° C.

2nd mixing stage:

Upon completion of the first stage of stirring, the mixture was passed to an attached roller and formed into a plate that was stored at room temperature for 24 hours.

The processing temperatures did not exceed 60 ° C.

3. Stirring stage:

In the 3rd mixing stage, further digestion in the kneader at 150 ° C followed.

4th degree of mixing:

Addition of additives: CHANCEL ground sulfur 90/95, VULKACIT® CZ / C, VULKACIT® D / C for rolling machine at temperatures not exceeding 80 ° C.

The prepared rubber mixtures and vulcanizates were subjected to the technical tests described below. The measured values are also shown in Tab. First

Tests on prepared rubbers and vulcanizates

Mooney viscosity measurement

The viscosity can be determined by the force by which the rubbers (and mixtures of rubbers) resist their processing. In a parallel plate viscometer according to Mooney, the fluted disk is filled from above and below with the test substance and moved in a tempered chamber at a frequency of about 2 revolutions per minute. The force exerted on this is measured as torque and corresponds to the corresponding viscosity. As a rule, the sample is preheated to 100 ° C for one minute; The measurement, at a constant maintained temperature, takes an additional 4 minutes.

The viscosity shall be reported together with the relevant test conditions, eg. ML (1 + 4) 100 ° C (M = Mooney viscosity; L = wide, large, large, rotor; preheat and measurement duration in minutes; temperature of measurement).

The viscosity values of the prepared rubbers listed in Table 1 were measured using a Mooney shear disc viscometer.

The reaction of the mixture to the scorch (Scorch) can also be measured by the same test. In this utility model, a temperature of 130 ° C was selected. The rotor runs until the torque value rises to 5 Mooney units after the minimum has been exceeded relative to the minimum value (t5). The higher the value (in seconds), the slower the vulcanization starts (high Scorch values).

SK 7977 Yl

Rheometer (vulcameter) vulcanization time 170 ° C / t95

The progress of vulcanization on a moving die rheometer (MDR) and the relevant analytical data were obtained using an MDR 2000 rheometer from Monsanto according to ASTM D5289-95. The results of this test are collected in Tab. Second

During vulcanization, the time at which 95% of the rubber was crosslinked at the selected temperature of 170 ° C was measured.

Determination of hardness (Shore A)

In order to determine the hardness of the rubber composition prepared in accordance with the present utility model, rubber layers coated on a 6 mm thick cylinder were made from the rubber composition prepared according to the formulas shown in Table 1. Samples with a diameter of 35 mm were cut from these layers and the hardness (Shore A) was measured with a digital tester manufactured by Zwick GmbH & KG, Ulm.

Tear test

The tear test is used directly to measure the elastomer load limits. The length of the specimen at rupture with respect to the house to its original length corresponds to the relative elongation at rupture. The force is also measured at certain elongation degrees, mostly 50, 100, 200 and 300%, and is expressed as the value of stress (tensile strength at said 300% elongation or Module 300).

The results of the measurements are shown in Tab. First

Dynamic damping

Dynamic measurement processes were used to characterize the deformation reaction of elastomers exposed to periodic load changes. The externally applied voltage changes the conformation of the polymer chain.

In this measurement, the loss factor tan δ is determined indirectly from the ratio of the loss module G 'and the storage module G ´.

Table 1

References. Example 1 Example 2 phr phr phr BUNACB 24 30 30 30 BUNAVSL 5025-1 96 96 96 CORAX N 339 6.4 6.4 6.4 VULKASIL S 80 80 80 TUDALEN 1849-1 8 8 0 EDENORC 1898-100 1 1 1 Vulkanox 4020 / LG 1 1 1 Vulcanox HS / LG 1 1 1 Zinc Beloba Red seal 2.5 2.5 2.5 ANTILUX 654 1.5 1.5 1.5 SI 69 6.4 6.4 6.4 Ground sulfur 90/95 CHANCEL 1.5 1.5 1.5 VULKACIT CZ / C 1.5 1.5 1.5 VULCACIT D / C 2 2 2 Cellulose acetate with triacetin 10 20 Mooney viscosity (ML 1 + 4) DIN 53523 [Me] 91 66 66 Cure time according to ASTMD (MS-t5) 5289-95 WITH 1085 1582 1468 Vulcanization time (t95%) DIN 53529 with 1213 1091 940 Hardness DIN 53505 [Shore A] 70 70 69 Module 300 DIN 53504 MPa 16 14 12 Elongation at break DIN 53504 % 338 377 388 Tensile strength DIN 53504 MPa 18 19 16 Friction wear DIN 53516 85 89 94 tan 5 (-1 ° C) indication of shear resistance on wet surfaces 0,458 0,416 0,399 Tan 5 (60 ° C) rolling resistance indication 0,147 0,142 0,123

SK 7977 Yl

As the results of Example 1 show, the tan value at 60 ° C (rolling resistance indicator) was reduced by the addition of an additive composed according to the present utility model of cellulose acetate and triacetin in an amount of 10 phr based on rubber. Simultaneously, the flowability (Mooney viscosity) decreased. In addition, the curing time of the vulcanization as well as the relative elongation at break were increased, and the duration of the curing was reduced while maintaining good shear resistance on wet surfaces (> 0.380). If, as can be seen in the results of Example 2, the amounts of softening oil (TUDALEN 1849-1) are omitted but the amount of cellulose acetate and triacetin used is further increased to 20 phr relative to the rubber, it turns out surprisingly that the rolling resistance and hence tan 5 can be greatly reduced without compromising other mechanical properties, such as e.g. elongation at break, tensile strength and hardness. Also in Example 2, it was possible to increase the cure time of the vulcanization, thereby increasing the safety of production as well as shortening the cure time.

PROTECTION REQUIREMENTS

Claims (15)

comprising at least one rubber, triacetin comprising 0.1 to 100 phr by that like by that he- by that like by that he- CLAIMS 1. Rubber mixtures, characterized by, and at least one filler from the series of cellulose and / or cellulose derivatives. Rubber mixtures according to claim 1, characterized in that. at least one cellulose and / or cellulose derivative and 0.1 to 80 phr triacetin. Rubber mixtures according to claims 1 and 2, characterized in that they comprise at least one rubber selected from the group of styrene-butadiene rubbers and polybutadiene rubbers. Rubber mixtures according to at least one of claims 1 to 3, characterized in that the cellulose derivative comprises cellulose acetate. Rubber mixtures according to at least one of Claims 1 to 4, characterized in that they comprise at least one further filler of the series of oxygen-containing hydroxyl-containing fillers. Rubber mixtures according to at least one of Claims 1 to 5, characterized in that the further filler comprises silicic acid having a specific surface area of 5 to 1000 m ² / g. Rubber mixtures according to at least one of claims 1 to 6, characterized in that they comprise at least one rubber of the series of synthetic rubbers, 0.3 to 30 phr cellulose and / or 0.3 to 30 phr cellulose acetate, 0.5 to 45 phr triacetin, to 10 phr at least one sulfur-containing acceleration system of a series of sulfur / sulfenamide systems, 50 to 90 phr of at least one oxygen-containing hydroxyl-containing filler, and 0.2 to 12 phr of at least one silane of a series of organic sulfur-containing silicon compounds. Rubber mixtures according to at least one of claims 1 to 7, characterized in that they comprise at least one rubber of the series of styrene-butadiene and polybutadiene rubbers, 0.3 to 30 phr cellulose and / or cellulose acetate and 0.5 to 45 phr triacetin, up to 10 phr of at least one sulfur-containing acceleration system from a series of sulfur / sulfenamide systems, 50 to 90 phr of silica having a specific surface area of 5 to 1000 m ² / g and 0.2 to 12 phr of at least one silane of bis (triethoxysilylpropyl) -tetrasulfide and bis ( triethoxysilylpropyl) disulfide. Use of a composition comprising at least one cellulose and / or a cellulose derivative and triacetin as an additive for the preparation of a rubber composition according to any one of claims 1 to 8. Use according to claim 9, characterized in that the mixture comprises at least 99 to 1 part by weight of at least one cellulose and / or cellulose derivative and 1 to 99 parts by weight of triacetin. Use of a rubber composition according to any one of claims 1 to 8 for the production of rubber vulcanizates or molded rubber product. Use according to claim 11, wherein the rubber vulcanizate and / or molded rubber product is in the form of a tire or tire part selected from the group consisting of tire treads, sidewalls, reinforced sidewalls of coasting tires, and apex mixtures. Use according to claim 11, wherein the rubber vulcanizate and / or molded rubber product is in the form of a technical rubber product selected from the group consisting of parts of dampers, cylinder linings, conveyor belts, belts, spindles and seals. Use according to claim 11, wherein the rubber vulcanizate and / or the shaped rubber product is in the form of a golf ball filling. Use according to claim 11, wherein the rubber vulcanizate and / or the shaped rubber product is in the form of a sole. End of document