1. A continuous process for reacting synthetic poly(carboxylic acids) (A) containing at least 10 repeat structural units of the formula (I)
in which
R9 is hydrogen, a C1- to C4-alkyl group or a group of the formula \u2014CH2\u2014COOH
R10 is hydrogen or a C1- to C4-alkyl group
R11 is hydrogen, a C1- to C4-alkyl group or \u2014COOH,
with amines (B) of the formula (II)
HNR1R2 \u2003\u2003(II)
in which
R1 is a hydrocarbyl radical which has 3 to 50 carbon atoms and may be substituted or contain heteroatoms, and
R2 is hydrogen or a hydrocarbyl radical which has 1 to 50 carbon atoms, which may be substituted or contain heteroatoms, or
R1 and R2 together with the nitrogen atom to which they are bonded form a ring, by introducing a reaction mixture comprising at least one synthetic poly(carboxylic acid) (A) and at least one amine of the formula (II) in a solvent mixture comprising water and, based on the weight of the solvent mixture, 0.1-75% by weight of at least one water-miscible organic solvent, where the organic solvent has a dielectric constant measured at 25\xb0 C. of at least 10, into a reaction zone, and exposing it to microwave radiation as it flows through the reaction zone, the reaction mixture in the reaction zone being heated to temperatures above 100\xb0 C. by the microwave irradiation.
2. The process as claimed in claim 1, in which the poly(carboxylic acid) (A) is a homopolymer of acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid or itaconic acid or a copolymer of two or more of these monomers.
3. The process as claimed in claim 1, in which the poly(carboxylic acid) (A) is a copolymer of acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid andor itaconic acid, and at least one further ethylenically unsaturated monomer.
4. The process as claimed in one or more of claims 1 to 3, in which the poly(carboxylic acid) has a mean molecular weight of at least 700 gmol.
5. The process as claimed in one or more of claims 1 to 4, in which the amine is a primary amine.
6. The process as claimed in one or more of claims 1 to 4, in which the amine is a secondary amine.
7. The process as claimed in one or more of claims 1 to 6, in which R1 is an aliphatic radical.
8. The process as claimed in one or more of claims 1 to 7, in which R2 is an aliphatic radical.
9. The process as claimed in one or more of claims 1 to 8, in which the amine is a polyether amine of the formula (III)
\u2014(R3\u2014O)n\u2014R4 \u2003\u2003(III)
in which
R3 is an alkylene group having 2 to 6 carbon atoms and preferably having 2 to 4 carbon atoms, for example ethylene, propylene, butylene or mixtures thereof,
R4 is hydrogen, a hydrocarbyl radical having 1 to 24 carbon atoms, an acyl radical of the formula \u2014C(\u2550O)\u2014R12 in which R12 is a hydrocarbyl radical having 1 to 50 carbon atoms, or a group of the formula \u2014R3\u2014NR5R6,
n is a number between 2 and 100, preferably between 3 and 500 and especially between 4 and 25, for example between 5 and 10, and
R5, R6 are each independently hydrogen, an aliphatic radical having 1 to 24 carbon atoms and preferably 2 to 18 carbon atoms, an aryl group or heteroaryl group having 5 to 12 ring members, a poly(oxyalkylene) group having 1 to 50 poly(oxyalkylene) units, where the polyoxyalkylene units derive from alkylene oxide units having 2 to 6 carbon atoms, or R5 and R6 together with the nitrogen atom to which they are bonded form a ring having 4, 5, 6 or more ring members.
10. The process as claimed in one or more of claims 1 to 9, in which the amine is a polyamine of the formula (IV)
\u2014R7\u2014N(R8)m\u2014(R8) \u2003\u2003(IV)
in which
R7 is an alkylene group having 2 to 6 carbon atoms and preferably having 2 to 4 carbon atoms, for example ethylene, propylene or mixtures thereof,
each R8 independently of any other is hydrogen, an alkyl or hydroxyalkyl radical having up to 24 carbon atoms, for example 2 to 20 carbon atoms, a polyoxyalkylene radical \u2014(R3\u2014O)p\u2014R4, or a polyiminoalkylene radical \u2014R7\u2014N(R8)L-(R8), where R3, R4, R7 and R8 have the meanings given above, and q and p each independently are 1 to 50, and
m is a number from 1 to 20 and preferably 2 to 10, for example three, four, five or six. The radicals of the formula (I) contain preferably 1 to 50, in particular 2 to 20, nitrogen atoms.
11. The process as claimed in one or more of claims 1 to 10, in which the reaction mixture used for conversion contains 10 to 99% by weight of a mixture of water and a water-miscible organic solvent.
12. The process as claimed in one or more of claims 1 to 11, in which the ratio between water and water-miscible organic solvent is between 10:1 and 1:5.
13. The process as claimed in one or more of claims 1 to 12, in which the water-miscible solvent is a protic organic liquid.
14. The process as claimed in claim 13, in which the water-miscible solvent is an alcohol.
15. The process as claimed in one or more of claims 1 to 12, in which the water-miscible solvent is an aprotic organic liquid.
16. The process as claimed in claim 15, in which the water-miscible solvent is selected from formamide, N,N-dimethylformamide (DMF), N,N-dimethylacetamide, acetone, \u03b3-butyrolactone, acetonitrile, sulfolane and dimethyl sulfoxide (DMSO).
17. The process as claimed in one or more of claims 1 to 16, in which the reaction is performed at temperatures above 100\xb0 C.
18. The process as claimed in one or more of claims 1 to 17, in which the reaction mixture comprises an acidic catalyst.
19. The process as claimed in one or more of claims 1 to 18, in which the reaction mixture comprises a strong electrolyte.
20. The process as claimed in one or more of claims 1 to 19, in which the microwave irradiation is effected in a flow tube made from microwave-transparent, high-melting material.
21. The process as claimed in one or more of claims 1 to 20, in which the longitudinal axis of the reaction tube in the direction of propagation of the microwaves is within a monomode microwave applicator.
22. The process as claimed in one or more of claims 1 to 21, in which the microwave applicator takes the form of a cavity resonator.
23. The process as claimed in one or more of claims 1 and 3 to 22, in which the synthetic poly(carboxylic acids) (A) is a copolymer which contains the structural units of the formula (I) derived from ethylenically unsaturated carboxylic acids in block, alternating or random sequence.
24. Hydrophobically modified synthetic poly(carboxylic acids) preparable by the process as claimed in one of more of claims 1 to 23.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1-5. (canceled)
6. A vehicle suspension including a subassembly constituted by a coil spring mounted to bear between two supports of variable spacing, wherein at least one support among said two supports is constrained to move along a trajectory that is curved relative to the other support among said two supports, and wherein the variation in the pitch of an end portion of a corresponding end turn bearing against said at least one support is negative or zero.
7. A vehicle suspension according to claim 6, wherein said end turn is off-center relative to a general axis of said spring.
8. A vehicle suspension according to claim 6, wherein said end turn is of a diameter smaller than a mean diameter of other turns of said spring adjacent to said end turn.
9. A vehicle suspension according to claim 7, wherein said end turn is of a diameter smaller than a mean diameter of other turns of said spring adjacent to said end turn.
10. A vehicle suspension according to claim 8, wherein said end turn is substantially tangential to a cylinder defined by said other turns when said spring is in a non-stressed state.
11. A vehicle suspension according to claim 8, wherein said at least one support includes a stud shaped and dimensioned so as to fit in said end turn.
12. A vehicle suspension according to claim 10, wherein said at least one support includes a stud shaped and dimensioned so as to fit in said end turn.