DE-102015218746-B4 - rubber compound and vehicle tires

Abstract

Containing sulfur-crosslinkable rubber compound - 20 to 70 phr of at least one functionalized styrene-butadiene copolymer A, wherein the functionalized styrene-butadiene copolymer is functionalized at at least one end of each polymer chain with an amino group-containing alkoxysilyl group and at least one further alkoxysilyl group(s) and/or at least one further amino group-containing alkoxysilyl group(s), and - 10 to 50 phr of at least one emulsion-polymerized styrene-butadiene rubber B, which in the unvulcanized state has a styrene content of 5 to 30 wt.%, and a vinyl content based on the butadiene content of 5 to 70 wt.%, and - 20 to 300 phr silica and/or carbon black.

Inventors

• Viktoria Pavon Sierra
• Norbert Müller
• Catarina Sá

Assignees

• CONTINENTAL REIFEN DEUTSCHLAND GMBH

Dates

Publication Date

20260513

Application Date

20150929

Claims (10)

1. Sulfur-crosslinkable rubber compound containing - 20 to 70 phr of at least one functionalized styrene-butadiene copolymer A, wherein the functionalized styrene-butadiene copolymer is functionalized at at least one end of each polymer chain with an amino-group-containing alkoxysilyl group and at least one further alkoxysilyl group(s) and/or at least one further amino-group-containing alkoxysilyl group(s), and - 10 to 50 phr of at least one emulsion-polymerized styrene-butadiene rubber B, which in the unvulcanized state has a styrene content of 5 to 30 wt.% and a vinyl content based on the butadiene content of 5 to 70 wt.%, and - 20 to 300 phr of silica and/or carbon black.
2. rubber compound according to Claim 1 , characterized in that the functionalized styrene-butadiene copolymer A is a solution-polymerized styrene-butadiene copolymer.
3. Rubber compound according to one of the preceding claims, characterized in that the functionalized styrene-butadiene copolymer A has a styrene content of 5 to 30 wt.%.
4. Rubber compound according to one of the preceding claims, characterized in that the functionalized styrene-butadiene copolymer A has a glass transition temperature of -15 to -70 °C.
5. Rubber compound according to one of the preceding claims, characterized in that the functionalized styrene-butadiene copolymer A comprises a further group selected from the group consisting of alkoxysilyl groups and amino group-containing alkoxysilyl groups.
6. Rubber compound according to one of the preceding claims, characterized in that it contains 3 to 30 phr of natural polyisoprene.
7. Rubber compound according to one of the preceding claims, characterized in that it contains 45 to 55 phr of the functionalized styrene-butadiene copolymer (A) and 25 to 35 phr of the ESBR (B) and 15 to 25 phr of at least one natural polyisoprene.
8. Rubber compound according to one of the preceding claims, characterized in that it contains 70 to 90 phr silica.
9. Vehicle tire which in at least one component contains at least one vulcanizate or at least one sulfur-curable rubber compound according to at least one of the Claims 1 until 8 exhibits.
10. Vehicle tires Claim 9 , characterized in that the component is at least the tread.

Description

The invention relates to a sulfur-crosslinkable rubber compound, in particular for treads of vehicle tires, and to a vehicle tire. The rubber composition of the tread largely determines the driving characteristics of a vehicle tire, especially a pneumatic tire. Similarly, the rubber compounds used in belts, hoses, and straps, particularly in areas subject to high mechanical stress, are essential for the stability and durability of these rubber products. Therefore, very high demands are placed on these rubber compounds used in vehicle tires, belts, and hoses. The partial or complete replacement of carbon black with silica in rubber compounds has, for example, improved the overall driving characteristics of tires in recent years. However, the well-known conflicts of objectives arising from opposing tire properties still exist even with silica-containing tread compounds. Thus, improvements in wet grip and dry braking performance generally still result in a deterioration of rolling resistance, winter performance, and wear characteristics. These properties are also important quality criteria for technical rubber products such as belts, straps, and hoses. Particularly with vehicle tires, numerous attempts have been made to positively influence tire properties by varying the polymer components, fillers, and other additives, especially in the tread compound. The focus here is primarily on rolling resistance and abrasion. It must be considered that an improvement in one tire property often leads to a deterioration of another. For example, within a given compound system, there are various known ways to optimize rolling resistance. These include lowering the glass transition temperature of the rubber compound, reducing the filler content, and changing the polymer system. All of these measures inevitably lead to a deterioration of at least one other tire property, such as abrasion resistance, wet grip, tear resistance, and/or handling characteristics of the given compound. To optimize the rolling resistance behavior or to optimize various other properties of rubber compounds relevant for use in tires without deteriorating the rolling resistance behavior, it is known to functionalize the diene rubber used in such a way that it bonds to the filler(s). For example, in the EP 2357211 A1 A rubber compound is disclosed which contains at least one aliphatic and/or aromatic hydrocarbon resin, at least one filler, and at least one functionalized diene monomer rubber, the functionalization of which is present along the polymer chain and/or at the end and enables binding to fillers. Hydroxyl groups are disclosed as functionalizations in Table 1 for binding the polymers to silica. As can be seen from the examples, 20 phr of a hydrocarbon resin are necessary as a plasticizer for the desired improvement in abrasion resistance and wet grip properties, although this deteriorates the rolling resistance. Also in the EP 0806452 A1 A rubber mixture is described which contains a functionalized diene rubber that carries, among other things, hydroxy groups as functional groups for bonding to silica. In the EP 1457501 A1 A functionalized styrene-butadiene copolymer is disclosed, which carries a primary amino group and an alkoxysilyl group as functional groups per styrene-butadiene copolymer chain. Furthermore, in the EP 1457501 A1 The study revealed rubber compounds containing this styrene-butadiene copolymer, as well as tires whose treads are made from this rubber compound. The tires are said to be characterized by a good balance between abrasion resistance, durability, hysteresis loss, and wet grip. Also from the EP 1837370 A1 A rubber compound is produced in which a functionalized styrene-butadiene copolymer is present, with each styrene-butadiene copolymer chain containing a primary amino group and an alkoxysilyl group as functional groups. In combination with a specific type of carbon black, this rubber compound exhibits improved tire properties such as wet braking, abrasion resistance, and rolling resistance. Also in the EP 2098384 B1 A rubber compound is disclosed which contains a solution-polymerized styrene-butadiene copolymer bearing an amino group and an alkoxysilyl group (amino-siloxane group) as functional groups. This results in an improvement in dry conditions. braking, handling, wet braking and abrasion behavior were achieved, although the influence on rolling resistance in the conflict of objectives is not disclosed. In the US 20070185267 A1 A rubber mixture is disclosed which may contain a conjugated diene-based copolymer which may be functionalized with an alkoxysilyl group and two amino groups. DE 11 2011 101 778 T5 Disclosing a rubber composition comprising a diene rubber containing three types of rubber (E-SBR, modified S-SBR and natural rubber (NR)) in a total amount of 80 wt.% or more; and a filler material in an amount of 100 to 140 parts by weight, based on 100 parts by weight of the diene rubber, wherein the filler