Hydroxyl group-containing diene rubber

Details Hydroxyl group-containing diene rubber Hydroxyl group-containing diene rubber

2002-01-18

2004-02-24

Nutter, Nathan M. (Department: 1711)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Mixing of two or more solid polymers; mixing of solid...

C525S232000, C525S241000, C526S335000, C526S336000, C524S492000, C524S495000

Reexamination Certificate

active

06696523

ABSTRACT:

FIELD OF THE INVENTION
The present invention provides rubber mixtures which contain a diene rubber with a concentration of primary hydroxyl groups of 0.1 to 2 wt. % and a glass transition temperature of −120 to −50° C. and their mixtures with fillers, optionally other rubbers and rubber auxiliary substances and vulcanisates prepared therefrom. Rubber mixtures according to the invention are suitable for producing highly reinforced, abrasion-resistant moulded items, in particular for producing tires which have particularly high wet skidding resistance.
BACKGROUND OF THE INVENTION
Double bond-containing solution rubbers, such as solution polybutadiene and solution styrene/butadiene rubbers, have advantages over the corresponding emulsion rubbers when producing low rolling resistance tire treads. The advantages are based, inter alia, on the ability to control the vinyl content, cis content and glass transition temperature and molecular branching associated therewith. Particular advantages in relation to abrasion, wet skidding resistance and rolling resistance of the tires result therefrom in a practical application. Thus, U.S. Pat. No. 5,227,425 describes the production of tire treads from a solution SBR rubber and silica. To further improve the properties, numerous methods for modifying the end groups have been developed, as is described e.g. in EP-A 334 042, with dimethylaminopropyl-acrylamide or, as described in EP-A 447,066, with silyl ethers. However, due to the high molecular weight of the rubber, the proportion by weight of end groups is small and can therefore have only a small effect on the interaction between filler and rubber molecule. The present invention is intended to provide solution diene rubbers such as solution polybutadiene and polyisoprene with a much higher concentration of effective groups for interacting with fillers.
A process for preparing hydroxyl group-containing solution polybutadiene rubbers is also described in DE-OS 2,653,144. These rubbers, however, have a much higher concentration of hydroxyl groups, associated with much higher glass transition temperatures.
EP-A 464,478 describes a process for hydroxylating rubber, wherein, however, secondary hydroxyl groups are introduced which are far less effective than the primary hydroxyl groups in the present invention.
Hydroxyl group-containing emulsion and solution rubbers are also described in EP-805,452 A1, wherein the hydroxyl concentrations described here for solution rubbers lie within a much lower range (0.009 to 0.061%), depending on the process used, and the glass transition temperatures are substantially higher (>−40° C.), depending on the styrene content, for the emulsion rubbers described.
SUMMARY OF THE INVENTION
It has now been found that rubber mixtures and rubber vulcanisates with surprisingly improved dynamic damping characteristics in the temperature range relevant to wet skidding resistance and the temperature range relevant to rolling resistance and also improved abrasion behaviour can be prepared from hydroxyl group-containing solution diene rubbers with a concentration of 0.1 to 2 wt. % of bonded primary hydroxyl groups and a glass transition temperature of −120 to −50° C. Further surprising advantages were obtained when the rubber mixture was prepared not in conventional compounders but by mixing a solution of hydroxyl group-containing rubber and oxidic or siliceous fillers in organic solvents and the solvent was then removed using steam, since then the filler is fully precipitated with the rubber and does not remain in the waste water, as when using an unmodified rubber.


REFERENCES:
patent: 3627856 (1971-12-01), Thienot
patent: 5070150 (1991-12-01), Hopper
patent: 5227425 (1993-07-01), Rauline
patent: 5409969 (1995-04-01), Hamada
patent: 5496883 (1996-03-01), Hamada
patent: 6252008 (2001-06-01), Scholl et al.
patent: 6319994 (2001-11-01), Scholl et al.
patent: 1 470 920 (1969-03-01), None
patent: 1 954 446 (1970-05-01), None
patent: 1 816 394 (1970-07-01), None
patent: 0 334 042 (1993-11-01), None
patent: 0 806 452 (1997-11-01), None
patent: 1575115 (1980-09-01), None
**C.S. Marvel et al.: “Polybutadiene Modified by Addition of Thiols Containing Polar Groups”, Industrial and Engineering Chemistry, band 45, No. 9, 1953,pp. 2090-2093 XP002144506.

Affiliated with

Also associated with

Rating

Hydroxyl group-containing diene rubber does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Hydroxyl group-containing diene rubber, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Hydroxyl group-containing diene rubber will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3301581