Dispersants prepared from high polydispersity olefin polymers

Details Dispersants prepared from high polydispersity olefin polymers Dispersants prepared from high polydispersity olefin polymers

2002-04-10

2002-12-31

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...

C525S191000, C525S213000, C525S215000, C525S216000, C525S222000, C525S224000, C525S240000, C525S241000, C525S374000, C525S379000, C525S384000

Reexamination Certificate

active

06500898

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention provides dispersants prepared from high polydispersity olefin polymers, which exhibit improved thickening properties especially in lubricant formulations. The invention also encompasses the intermediate acylating agents which react with amines to form such dispersants, as well as a process for preparing the same.
Dispersants are well known materials useful in a variety of applications, including especially lubricants for internal combustion engines. U.S. Pat. No. 4,234,435, Meinhardt et al., Nov. 18, 1980, discloses carboxylic acid acylating agents derived from polyalkenes and a dibasic, carboxylic reactant such as maleic or fumaric acid or certain derivatives thereof. The acylating agents can be reacted with a further reactant subject to being acylated such as polyethylene polyamines and polyols to produce derivatives useful as lubricant additives.
Polyolefins have been prepared by polymerization catalyzed with heteropolyacids. U.S. Pat. No. 5,710,225, Johnson et al., Jan. 20, 1998, discloses a method for producing polymers by polymerization of olefins, by contacting a C
2
-C
30
olefin or derivative thereof with a heteropolyacid. The heteropolyacid catalyst can be a partially or fully exchanged with cations from the elements in groups IA, IIA and IIIA of the periodic chart, Group IB-VIIB elements and Group VIII metals, including manganese, iron, cobalt, nickel, copper, silver, zinc, boron, aluminum, bismuth, or ammonium or hydrocarbyl-substituted ammonium salt. The heteropolyacids can be used in their initial hydrated form or they can be treated (calcined) to remove some or all of the water of hydration. The calcining is preferably conducted in air at a temperature of, for instance, up to 375° C.; temperatures much over 350° C. do not generally provide much advantage. In the resulting polymers, the combined terminal vinylidene and &bgr;-isomer content is preferably at least 30%.
U.S. Pat. No. 5,614,480, Salomon et al, Mar. 25, 1997, discloses lubricating compositions and concentrates which include carboxylic derivatives produced by reacting a substituted succinic acylating agent containing at least about 50 carbon atoms in the substituent, with certain amines. The substituent can be a polyalkene having an {overscore (M)}
n
value of 1300 to about 5000 and an {overscore (M)}
w
/{overscore (M)}
n
value of about 1.5 to about 4.5.
It is believed to be desirable to use highly reactive polyolefins to prepare hydrocarbyl-substituted acylating agents (e.g., anhydrides) by way of a thermal route rather than a chlorine catalyzed route. The thermal route avoids products containing chlorine. The reactivity of the polyolefin is believed to be related to the end group in the polymer with terminal olefins (terminal vinylidene) and terminal groups capable of being isomerized thereto being identified as the reactive species. The groups capable of being isomerized to the terminal vinylidene (I) group are the &bgr;-isomers (II) of Table 1.
The thermal route to substituted succinic anhydrides using highly reactive PIB's has been discussed in detail in U.S. Pat. Nos. 5,071,919, 5,137,978, 5,137,980 and 5,241,003, all issued to Ethyl Petroleum Additives, Inc.
The isomer content of a conventional (AlCl
3
) and high terminal vinylidene polyisobutylenes (PIB's) are shown in Table 1. Conventional PIB has terminal vinylidene content of roughly 5%. The terminal isomer groups of conventional PIB and high vinylidene PIB are given below in Table 1 and those published in EPO 0355 895. However, in this invention polyisobutylene containing relatively high content of vinylidene and &bgr;-isomers can be formed. Such materials can contain at least 30 percent terminal vinylidene (I) and &bgr;-isomer (II) groups, as shown below. In preferred cases the polyisobutylene can contain at least 30 percent terminal vinylidene (I) groups, and more preferably at least 60 percent terminal vinylidene groups.
TABLE 1
PIB
Percent in
Terminal Groups
Conventional PIB
4-5%


63-67%

22-28%


5-8%

Other
 0-10%
Conventional PIBs are commercially available under various tradenames including Parapol® from Exxon, Lubrizol® 3104 and 3108 from Lubrizol, Indopol® from Amoco, and Hyvis® from BP. Conventional PIBs have number average molecular weight in the range of 300-5000, but the preferred number average molecular weight is in the range of 500-2000.
SUMMARY OF THE INVENTION
The present invention provides a dispersant which is the reaction product of an amine, an alcohol, or mixtures thereof, and a hydrocarbyl-substituted acylating agent, wherein the hydrocarbyl-substituent comprises at least one polymerized olefin, the resulting polyolefin having {overscore (M)}
w
/{overscore (M)}
n
of greater than 4 or 5, preferably 6 or 7.5 to 20. The polyolefin preferably has {overscore (M)}
n
of at least 1500, and preferably at least 30% terminal vinylidene (I) groups.
The invention further provides a dispersant above wherein the polyolefin is prepared by contacting (a) at least one C
2
-C
30
olefin or polymerizable derivatives thereof with (b) a catalyst comprising a partially or fully neutralized ammonium salt of a heteropolyacid, wherein said catalyst has been calcined, preferably at above 350° C. to 500° C.
The present invention further provides a method for preparing a dispersant, comprising the steps of reacting a hydrocarbyl-substituted acylating agent, wherein the hydrocarbyl group is a polyolefin having {overscore (M)}
w
/{overscore (M)}
n
of greater than 5, with an amine.
The present invention further provides a hydrocarbyl-substituted acylating agent, wherein the hydrocarbyl group is a polyolefin as described above.
DETAILED DESCRIPTION OF THE INVENTION
The dispersants of the present invention include acylated amines, that is, a reaction product of one or more hydrocarbyl substituted acylating agents, particularly hydrocarbyl-substituted carboxylic acylating agents, and one or more amines characterized by the presence within its structure of at least one >N—H group. The acylated amines are prepared in a well-known manner by reacting normally a stoichiometric excess of amine with a hydrocarbyl-substituted carboxylic acylating agent. That is, preferably greater than 1 equivalent of amine is reacted with each equivalent of carboxylic acid of the acylating agent. In certain preferred embodiments, at least 1.2 or 1.4 equivalents, and up to 8, preferably 7, 6, or 4 equivalents of amine are reacted with each equivalent of carboxylic group of the acylating agent. In another preferred embodiment, 1.0 to 1.5 equivalents of amine are reacted with each equivalent of carboxylic acid of the acylating agent.
The acylating agents used to prepare the dispersants are hydrocarbyl-substituted acylating agents. The hydrocarbyl group is substantially a polyolefin, with polydispersity and other features as described below; generally it has a number average molecular weight of at least 600, 700, or 800, to 5000, 3000, 2500, 1600, 1300, or 1200. The hydrocarbyl group is typically derived from a polyalkene, including homopolymers and interpolymers of olefin monomers having 2 to 16, to 6, or to 4 carbon atoms, and mixtures thereof. In a preferred embodiment the polyalkene is polyisobutene. Such polyalkenes are prepared by the methods set forth in greater detail in the present invention.
Suitable olefin polymer hydrocarbyl groups, having suitable polydispersity, can be prepared by heteropolyacid catalyzed polymerization of olefins under certain conditions. Preparation of polyolefins under such conditions is also described in copending U.S. application No. 09/344,129 filed Jun. 24, 1999.
Heteropolyacids are well known materials. Such catalysts can exist as the free acid or as a salt of a heteropolyanion. Heteropolyanions are polymeric oxoanions formed by a condensation reaction of two or more different oxoanions, e.g.,
 12WO
4
2−
+HPO
4
2−
+23H
+
→(PW
12
O
40
)
3−
+12H
2
O
A variety of structures are known for these materials; they can hav

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