Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
1999-11-30
2002-05-21
Wu, David W. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C526S318200, C526S318000, C526S317100, C526S319000, C526S329700
Reexamination Certificate
active
06391996
ABSTRACT:
This invention concerns copolymers that can be obtained by the ATRP method and concentrates and lubricant oils that contain these copolymers, a method for preparation of these copolymers as well as their use as pour point depressants.
Lubricants, especially mineral oils obtained from petroleum by distillation, for example, contain as a rule long-chain n-alkanes, which on the one hand bring about good viscosity/temperature, but on the other hand precipitate out in crystalline form upon cooling and in this way have an adverse effect on the flow of the oil or completely prevent (“plug”) it. An improvement of low temperature flow properties can be achieved, for example, by dewaxing. However, costs rise considerably if complete dewaxing is supposed to be achieved. For this reason a pour point range down −15° C. is achieved by partial dewaxing, and this pour point can. be further lowered by the addition of the so called pour point depressants or pour point improvers. These agents can effectively reduce the pour point even in concentrations of 0.01 to 1% by weight.
However, the mode of action of these compounds has not yet been completely clarified. In any case it is assumed that paraffin-like compounds become incorporated into the growing paraffin crystal surfaces and so stop further crystallization and in particular the formation of extended crystal structures.
Certain structural elements are known to have pour point depressant activity. In particular, polymers with sufficiently long alkyl side chains exhibit a pour point and flow improving effect. Here it is assumed that these alkyl groups become incorporated into the growing paraffin crystals and disrupt crystal growth (see Ullmann's Encyclopedia of Industrial Chemistry, 4
th
Edition, Vol. 20, Verlag Chemie, 1981, p. 548). On top of that, it is required of industrially usable pour point depressants that they have good thermal, oxidative and chemical stability, shear strength, etc. Moreover, it should be possible to produce the pour point and flow improvers on a cost favorable basis, since they are used in large quantities.
Polymethacrylates with long chain alkyl residues are used to a wide extent as pour point depressants or flow improvers. These compounds are described, for example, in U.S. Pat. Nos. 2,091,627, 2,100,993, 2,114,233 and EP-A-0 236 844. In general, these pour point depressants are produced by radical polymerization. Accordingly, they can be produced on a cost favorable basis. Their low temperature properties, which follow for example from the pour points in accordance with ASTM D-97, the minirotary viscosimetry test values in accordance with ASTM D-4684 or the scanning Brookfield results in accordance with ASTM D-5133, are usable for many applications, but all the same the low temperature properties are still not sufficient for many application.
Here one should take into account that more effective additives could be added in a smaller quantity in order to achieve a desired flow property at low temperatures. With the amounts of lubricants and diesel biofuels that are used there would be a considerable potential for savings even with relatively small differences.
Taking into consideration the prior art, it is now a task of this invention to make available additives through which improved flow properties of lubricants and diesel biofuels at low temperatures can be achieved, compared to the traditional additives. In addition, a task of the invention was to make available additives that have high stability with respect to oxidation and thermal stress as well as high shear strength. At the same time, the new additives are supposed to be produceable in a simple and economical way.
These as well as other not explicitly mentioned tasks, which, however, can easily be derived or developed from the introductory material, are solved by a polymer with all of the characteristics of claim
1
. Expedient modifications of the copolymers in accordance with the invention are provided protection in the claims that refer back to claim
1
. With regard to the concentrate as lubricant additive, claim
4
provides the solution of the underlying task, while claims
6
and
9
protect lubricants or diesel biofuels that contain the polymers in accordance with the invention. Claims
11
and
14
represent a solution of the problem with respect to the method for preparation of copolymers and their use.
Copolymers that have high efficiency as pour point depressants or flow improvers are obtained by the fact that ethylenically unsaturated monomers are polymerized by means of initiators that have a transferable atomic group, and one or more catalysts that contain at least one transition metal, in the presence of ligands that can form a coordination compound with the metallic catalyst(s), where the mixture of ethylenically unsaturated monomers consists of
a) 0 to 40% by weight of one or more ethylenically unsaturated ester compounds of formula (I)
where R is hydrogen or methyl, R
1
means a linear or branched alkyl residue with 1 to 5 carbon atoms, R
2
and R
3
independently represent hydrogen or a group of the formula —COOR′, where R′ means hydrogen or a alkyl group with 1 to 5 carbon atoms,
b) 10 to 98% by weight of one or more ethylenically unsaturated ester compounds of formula (II)
where R is hydrogen or methyl, R
4
means a linear or branched alkyl residue with 6 to 15 carbon atoms, R
5
and R
6
independently are hydrogen or a group of the formula —COOR″, where R″ means hydrogen or an alkyl group with 6 to 15 carbon atoms,
c) 0 to 80% by weight of one or more ethylenically unsaturated ester compounds of formula (III)
where R is hydrogen or methyl, R
7
means a linear or branched alkyl residue with 16 to 30 carbon atoms, R
8
and R
9
independently are hydrogen or a group of the formula —COOR′″ where R′″ means hydrogen or an alkyl group with 16 to 30 carbon atoms,
d) 0 to 50% by weight comonomer,
where the data in % by weight refer in each case to the total weight of the ethylenically unsaturated monomers. The pour point depressant effect can be determined, for example, in accordance with ASTM D 97.
Moreover, lubricants that contain the copolymers in accordance with the invention produce excellent minirotary viscosmetry values (MRV), which can be produced in accordance with ASTM D 4684, and scanning Brookfield results, as are obtained in accordance with ASTM D 5133.
Diesel biofuels, which contains copolymers of the present invention, exhibit exceptional results in cold filter plugging point measurements by IP 309 or low temperature flow tests in accordance with ASTM D 4539.
If certain flow properties at a given temperature are supposed to be achieved, the amount of additive can be reduced through this invention.
At the same time a number of other advantages can be achieved through the copolymers in accordance with the invention. Among these are:
The copolymers of this invention are characterized by a narrow molecular weight distribution. A high stability toward shearing effects is achieved through this.
The copolymers in accordance with the invention can be produced on a cost favorable basis.
The copolymers exhibit high resistance to oxidation and are chemically very stable.
Copolymers are substantially known; they are polymers that are obtained by polymerization of two or more different monomers. This term is to be understood broadly, so that statistical copolymers, block copolymers which contain two, three or more blocks, graft copolymers and gradient polymers are included in it.
The compositions from which the copolymers in accordance with the invention contain, in particular, (meth)acrylates, maleates and fumarates that have different alcohol residues. The term (meth)acrylates includes methacrylates and acrylates as well as mixtures of the two. These monomers are to a large extent known. Here the alkyl residue can be linear, cyclic or branched.
Mixtures from which the copolymers in accordance with the invention can be obtained can contain 0 to 40% by weight, especially 0.5
Scherer Markus
Souchik Joan
Cheung William K
RohMax Additives GmbH
Wu David W.
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