Plastic and nonmetallic article shaping or treating: processes – Recycling of reclaimed or purified process material – Of gaseous process material
Patent
1993-05-18
1995-06-20
Kuhns, Allan R.
Plastic and nonmetallic article shaping or treating: processes
Recycling of reclaimed or purified process material
Of gaseous process material
264115, 264123, 264DIG69, B29C 4302
Patent
active
054259045
DESCRIPTION:
BRIEF SUMMARY
This invention relates to a process for activating vulcanized (cured) waste rubber particles by treating the waste rubber particles with a non-vulcanized rubber polymer and a vulcanizing agent.
In order to prevent waste rubber and in particular the growing quantity of scrapped automobile tires from becoming damaging to the environment, it is highly desirable to recycle this material. Recycling of waste rubber can be carried out by grinding and adding the waste rubber particles to rubber mixtures for manufacturing new products. This process, however, leads to a strong deterioration of the physical properties. Another method of recycling is to reclaim the waste rubber in which the network formed by vulcanization is thermally degraded. The reclaimed material can be added to rubber mixtures for manufacturing new products. This process leads to a loss of physical properties, because the properties of the reclaimed material are poor in comparison with virgin polymers which due to the random decomposition of the network during reclaiming. U.S. Pat. No. 4,481,335 proposes a process for activating cured waste rubber particles. In this process 100 parts by weight of particulate, cured rubber are mixed with from 1 to 5 parts by weight of a liquid, sulfur-curable polymeric binder having ethylenic unsaturation and being soluble in hexane and/or benzene and having a viscosity at 140.degree. C. of not greater than about 10.sup.6 cp, and with a curing agent in a quantity of from 50 to 500% by weight of the polymeric binder.
The polymeric binder is preferably a homopolymer or copolymer of 1,4-butadiene. The applied polymers have a molecular weight of from 1000 to 100,000, and preferably from 1000 to 50,000. The polymeric binder is obtained by drying a commercially available aqueous emulsion, e.g. by stirring the emulsion in a Waring mixer at approximately 65.degree. C. The curing agent may be any of the curing agents commonly used, such as sulfur or sulfur donors. The waste rubber particles, the polymeric binder and the curing agent are mixed at a temperature of approximately 60.degree. to 140.degree. C. until a homogeneous, dry mixture is obtained.
The obtained activated waste rubber particles can be added in a quantity of preferably 25 to 75% by weight to rubber mixtures for producing rubber-like products, wherein the loss of physical properties is considerably reduced in comparison with the application of untreated waste rubber particles. The subsequent PCT-application WO 88/02313 of the same applicant as that of the above-mentioned U.S. patent specification relates to a vehicle tire having a tread portion comprising the cured product of a rubber molding composition containing from 20 to 80% by weight of waste rubber particles activated by the process of the above U.S. patent specification. The tensile strength and the elongation-at-break properties of the treads are less than those by applying rubber mixtures without activated rubber particles, while the wear resistance is as good as that when applying rubber mixtures without activated rubber particles. Thus a mixture of 40% by weight of activated rubber particles and 60% by weight of styrene-butadiene rubber compound gives a product having an approximately 25% lower tensile strength than when only the styrene-butadiene rubber compound i used.
DE-A-2,009,869 discloses a process for manufacturing an article wherein vulcanized waste rubber particles are mixed with a rubber latex and a vulcanizing system. A crumbly product is obtained which is brought into moulds and compressed. Then the filled moulds are dried by blowing air. Finally the moulded product is optionally subjected to a second compression yielding a more dense product. Using the process of DE-A-2,009,869 it is only possible to make rubber-like articles entirely consisting of activated waste rubber particles. Said articles have relatively poor physical properties.
The object of the present invention is to provide a more simple process for activating vulcanized waste rubber particles. Further it is an object of
REFERENCES:
patent: 4003408 (1977-01-01), Turner
patent: 4125578 (1978-11-01), Sear
patent: 4290470 (1981-09-01), Williams et al.
patent: 4320082 (1982-03-01), Houle
patent: 4382052 (1983-05-01), Arimatsu
patent: 4440208 (1984-04-01), Trickel et al.
patent: 4481335 (1984-11-01), Stark, Jr.
patent: 5075057 (1991-12-01), Hoedl
patent: 5094905 (1992-03-01), Murray
patent: 5114648 (1992-05-01), Kuc, Sr.
Derwent Publications Ltd., London GB. Class A, AN81-03101D, re JP55145 744.
Kuhns Allan R.
Vredestein Icopro B.V.
LandOfFree
Process for activating vulcanized waste rubber particles and a p does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for activating vulcanized waste rubber particles and a p, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for activating vulcanized waste rubber particles and a p will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1842724