Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
1997-10-30
2001-08-28
Lipman, Bernard (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S329300, C525S332600, C525S347000, C525S374000
Reexamination Certificate
active
06281295
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to vulcanization accelerators consisting of compounds belonging to the group of enamines.
More specifically, the present invention relates to vulcanization accelerators consisting of compounds, deriving from primary or secondary aliphatic amines, belonging to the group of enamines and a process for their preparation.
2. Discussion of the Background
It is known that the vulcanization of natural or synthetic rubbers takes place by the cross-linking between polymeric chains owing to the use of sulfur or peroxides.
The vulcanization process in the presence of sulfur has been optimized by the use of accelerators capable of limiting the vulcanization times and guaranteeing repeated results with respect to the properties of the end-products.
There are many known products which are used as vulcanization accelerators as described, for example, by Kirk-Othmer: “Encyclopedia of Chemical Technology”, Vol. 20, pages 337-364. Among these mercaptobenzothioazol and its sulfenamides, dithiocarbamates and thiuram disulfides, can be mentioned.
Frequently, in order to obtain good results, these products are not used alone but are combined with each other.
Among vulcanization accelerators there is a group of products defined as secondary accelerators, used as activators of primary accelerators with a thiazole base. Examples of these products are: N,N′-diphenylguanidine (DPG), N,N′-diortho-toluylguanidine (DOTG), 2,4,6-tris-dimethylaminomethylphenol and the condensation products of aromatic amines with aliphatic aldehydes.
European patent application 634.448, filed by the Applicant, describes vulcanization accelerators consisting of compounds belonging to the group of enamines having the following general formula:
wherein:
R′
1
and R′
2
, the same or different, represent a C
1
-C
18
alkyl group, linear or branched; a C
2
-C
18
alkenyl group; a C
3
-C
8
cycloalkyl group; a C
6
-C
18
aryl group; a C
7
-C
20
alkylaryl or arylalkyl group; or R′
1
and R′
2
, considered jointly with the nitrogen atom, represent a C
3
-C
8
heterocyclic group possibly containing a second heteroatom selected from O, S and N;
R′
3
and R′
4
, the same or different, represent a hydrogen atom; a C
1
-C
18
alkyl group, linear or branched; a C
2
-C
18
alkenyl group; a C
6
-C
18
aryl group; a C
7
-C
20
alkylaryl or arylalkyl group; or R′
3
and R′
4
, considered jointly with the double bond C═C to which they are linked, represent a C
3
-C
12
cycloalkenyl group;
R′
5
represents a hydrogen atom; a C
1
-C
18
alkyl group, linear or branched; a C
2
-C
18
alkenyl group; or, when R′
3
represents a hydrogen atom, a linear or branched C
1
-C
18
alkyl group, a C
2
-C
18
alkenyl group, a C
6
-C
18
aryl group or a C
7
-C
20
alkylaryl or arylalkyl group, R′
4
and R′
5
, considered jointly with the carbon atom which has the double bond C═C, represent a C
3
-C
12
cycloalkylene group.
The Applicant has now found compounds, deriving from primary or secondary aliphatic amines, belonging to the group of enamines, which can be used as vulcanization accelerators and have improved properties with respect to those known in the art. In fact, the above enamines are less volatile, are not irritating and generally have no odour.
SUMMARY OF THE INVENTION AND BRIEF DESCRIPTION OF THE DRAWINGS
The present invention therefore relates to vulcanization accelerators consisting of compounds belonging to the group of enamines having general formula (I):
wherein:
R
1
and R
2
, the same or different, represent a hydrogen atom; a C
1
-C
18
alkyl group, linear or branched; a C
2
-C
8
alkoxyalkyl group, linear or branched; a C
3
-C
8
cycloalkyl group possibly containing a heteroatom selected from oxygen, nitrogen and sulfur; a C
7
-C
20
arylalkyl group; or R
1
and R
2
, considered jointly with the nitrogen atom, represent a C
3
-C
8
heterocyclic group possibly containing a second heteroatom selected from oxygen, nitrogen and sulfur;
R
3
represents a C
1
-C
18
alkyl group, linear or branched; a C
6
-C
18
aryl group; a C
7
-C
20
alkylaryl or arylalkyl group; a C
1
-C
8
alkoxyl group linear or branched.
Examples of R
1
and R
2
radicals, apart from the hydrogen atom, are methyl, ethyl, propyl, butyl, octyl, cyclohexyl, benzyl, methoxyethyl, etc.
Examples of C
3
-C
8
heterocyclic groups, when R
1
and R
2
are considered jointly with the nitrogen atom, are morpholine, pyrrolidine, piperidine, piperazine, thiomorpholine, thiazolidine, benzothiazolidine, etc.
Examples of R
3
radicals are methyl, ethyl, propyl, phenyl, oxymethyl, oxyethyl, etc.
The capacity of the compounds having general formula (I) to act as vulcanization accelerators was shown by rheometric curves which are indicated in
FIGS. 2-4
(the time is indicated in abscissa; the torque in ordinate; the meanings of the letters appearing on the rheometrical curves will be provided later) obtained by measuring the stress of an oscillating disk englobed in a rubber sample during vulcanization. The rheometrical curves were determined using a Rheometer 100 of Monsanto.
The compounds having general formula (I) can be used alone or combined with other vulcanization accelerators such as, for example, mercapto-benzothiazole sulfenamides.
REFERENCES:
patent: 1780334 (1930-11-01), Burnett
patent: 4082706 (1978-04-01), Danielson
patent: 0 634 448 (1995-01-01), None
Chem Abst, 84:4878z (1976).*
Chem Abst, 88:22305x (1978).*
Chem Abst, 104:50616s (1986).*
Chemical Abstracts, vol. 112, No. 10, AN 79168, Mar. 5, 1990, JP-A-01 172 437, Jul. 7, 1989.
Organikum, pp. 479-482, 1977, “Reaktionen Von Aldehyden Und Ketonen Mit Aminoverbindungen”.
Rubber Journal, vol. 154, No. 1, pp. 24 and 26, Jan. 1, 1972, S.H. Morrell, et al., “Accelerators Based on Phenyl-&bgr;-Aminoketones”.
Y, Kawaoka, “Recent Problems in Vulcanisation”, Nippon Gomu Kyokaisha, 1981, No. 8, p. 517.
Kirk-Othmer Encyclopedia, vol. 20, pp. 335-360.
Kirk-Othmer Encyclopedia, 4thEdition, vol. 21, pp. 460-464 and 468.
Adovasio Mauro
Broussard Fabio
Callierotti Corrado
Roncalli Jose
Taroni Gianbattista
Great Lakes Chemical Italia S.r.l.
Lipman Bernard
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
LandOfFree
Enamines as vulcanization accelerators for natural or... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Enamines as vulcanization accelerators for natural or..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Enamines as vulcanization accelerators for natural or... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2511545