Compositions: coating or plastic – Coating or plastic compositions – Bituminous material or tarry residue
Reexamination Certificate
1997-08-14
2003-01-21
Rickman, Holly (Department: 1773)
Compositions: coating or plastic
Coating or plastic compositions
Bituminous material or tarry residue
C106S281100, C524S571000, C428S489000
Reexamination Certificate
active
06508875
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a bituminous composition. In particular, the present invention relates to a bituminous composition for use in floor covering and/or sound or vibration damping applications.
BACKGROUND OF THE INVENTION
Bituminous compositions for use in sound or vibration damping applications are known in the art. A general overview is given in The SHELL Bitumen Industrial Handbook (1995) by P. Morgan and A. Mulder. An overview of sound and vibration damping is given in ASC Symposium Series (1989) Sound and Vibration Damping with Polymers by R. D. Corsaro and L. H. Sporling, editors.
One important sound or vibration damping application of bituminous compositions is in floor coverings. Floor coverings, e.g. carpets, carpet tiles, rugs etc., are known which comprise a fibrous material such as a woven or non-woven fabric. It is also known to provide certain floor coverings, especially those of the non-woven type e.g. felt or tufted floor coverings, with usually an integral backing layer to protect the floor covering against wear and to improve the dimensional stability thereof. It is important that the floor coverings provided with such backing layers are sufficiently flexible to prevent cracks forming in the backing layer during the transport, storage and laying thereof and are also, when in place on a floor, able to withstand heavy loads without the surface thereof remaining indented for an undesirable length of time after the heavy load has been removed.
For that purpose many backing layers nowadays comprise a polymer-modified bitumen component. In this respect reference can for instance be made to EP 0006674 B1 wherein the use has been described of a mixture containing a bitumen and a styrene-butadiene-styrene block copolymer for an integral backing layer of a fibrous floor covering. The amount of block copolymer to be used in such backing layers is, however, relatively high, making their use economically less attractive.
It would be desirable if economically attractive bituminous compositions could be provided for use in sound or vibration damping applications over a wide temperature range and/or a wide frequency range. It would further be desirable if bituminous compositions containing a relatively small amount of block copolymer could be provided for use as the backing layer of floor coverings.
SUMMARY OF THE INVENTION
Accordingly, the present invention provides a bituminous composition which comprises a bitumen component, less than 15% by weight of a block copolymer composition, based on total weight of block copolymer composition and bitumen component, and more than 40% by weight of a filler, based on total weight of the bitumen component, block copolymer composition, and filler, which block copolymer composition comprises at least one block of conjugated diene and at least two blocks of a monovinylaromatic hydrocarbon, wherein the block copolymer composition has a vinyl content of at least 25% by weight based on the total diene content and optionally a diblock content of 25 wt % or less, and any diblock copolymer present has an apparent molecular weight which is in the range of from 60,000 to 170,000.
With the term “apparent molecular weight” as used throughout the specification is meant the molecular weight of a polymer, as measured with gel permeation chromatography (GPC) using poly(styrene) calibration standards (according to ASTM D 3536).
By “diblock content”, there should be understood the amount of non-coupled diblock copolymer that is finally present in the prepared block copolymer composition. Where the block copolymer is prepared via the full sequential preparation method, normally only triblock copolymers are formed. The triblock copolymers typically have an apparent molecular weight in the range from 120,000 to 340,000. The diblock content is preferably less than 20% wt, more preferably 15 wt % or less.
DETAILED DESCRIPTION OF THE INVENTION
The block copolymer composition constituents may be either linear or radial; good results have been obtained with both copolymer types. The block copolymer composition constituents include linear triblock copolymers (ABA), multi-armed block copolymers ((AB)
n
X) and diblock copolymers (AB), with A representing a monovinyl aromatic hydrocarbon polymer block, B representing a conjugated diene polymer block, n being an integer of 2 or higher, preferably from 2 to 6 and X representing the residue of a coupling agent. The coupling agent may be any di- or polyfunctional coupling agent known in the art, for example, dibromoethane, silicon tetrachloride, diethyl adipate, divinylbenzene, dimethyldichlorosilane, methyl dichlorosilane. Particularly preferred in such a preparation route is the use of non-halogen containing coupling agents, for example gamma-glycidoxypropyl-trimethoxysilane and diglycidylether of bisphenol A.
The block copolymers, which are useful as modifiers in the bituminous compositions according to the present invention, may be prepared by any method known in the art including the well known full sequential polymerisation method, optionally in combination with reinitiation, and the coupling method, as illustrated in e.g. U.S. Pat. Nos. 3,231,635; 3,251,905; 3,390,207; 3,598,887 and 4,219,627 and EP 0413294 A2, 0387671 B1, 0636654 A1, WO 94/22931, which are herein incorporated by reference. The block copolymer may therefore, for example, be prepared by coupling at least two diblock copolymer molecules AB together.
Techniques to enhance the vinyl content of the conjugated diene portion are well known and may involve the use of polar compounds such as ethers, amines and other Lewis bases and more in particular those selected from the group consisting of dialkylethers of glycols. Most preferred modifiers are selected from dialkyl ether of ethylene glycol containing the same or different terminal alkoxy groups and optionally bearing an alkyl substituent on the ethylene radical, such as monoglyme, diglyme, diethoxyethane, 1,2-diethoxy-propane, 1-ethoxy-2,2-tert-butoxyethane, of which 1,2-diethoxypropane is most preferred.
The apparent molecular weight-of-diblock copolymer (AB) is in the range of from 60,000 to 170,000. Preferably, said diblock copolymer apparent molecular weight is in the range of from 60,000 to 130,000, more preferably from 70,000 to 120,000.
The content of monovinyl aromatic hydrocarbon of the final block copolymer is suitably in the range of from 10 to 55% by weight, preferably in the range of from 20 to 45% by weight, and more preferably 25 to 40% by weight, based on the total block copolymer. Suitable monovinyl aromatic hydrocarbons include styrene, o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 2,4-dimethylstyrene, &agr;-methylstyrene, vinylnaphthalene., vinyltoluene and vinylxylene, or mixtures thereof of which styrene is the most preferred.
Suitable conjugated dienes include those having from 4 to 8 carbon atoms, for example 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene and 1,3-hexadiene. Mixture of such dienes may also be used. Preferred conjugated dienes are 1,3-butadiene and isoprene, with 1,3-butadiene being the most preferred.
The total vinyl content of the block copolymer is at least 25% by weight. Typically, the vinyl content is in the range of from 30 to 80% by weight, preferably from 35 to 65% by weight, more preferably from 35 to 55% by weight, even more preferably from 45 to 55% by weight, and most preferably from 50 to 55% by weight.
It will be appreciated that with the term “vinyl content” actually is meant that a conjugated diene is polymerised via 1,2-addition. Although a pure “vinyl” group is formed only in the case of 1,2 addition polymerisation of 1,3 butadiene, the effects of 1,2 addition polymerisation of other conjugated dienes on the found final properties of the block copolymer and the blends of it with bitumen will be the same.
The bitumen component may be a naturally occurring bitumen or derived from a mineral oil. Also petroleum pitches obtained by a cracking process and coal t
Bodt Duco
Heimerikx Gerardus Wilhelmus Jozef
Kraton Polymers U.S. LLC
Rickman Holly
LandOfFree
Bituminous composition does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Bituminous composition, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Bituminous composition will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3072758