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EP-4061857-B1 - POLYMER DISPERSION MADE FROM (METH)ACRYLATES HAVING LONG SIDE CHAINS

EP4061857B1EP 4061857 B1EP4061857 B1EP 4061857B1EP-4061857-B1

Inventors

  • SCHENDERLEIN, Helge
  • SCHMITT, GEROLD
  • EBERT, MARTINA
  • OSCHMANN, Hans-Jörg

Dates

Publication Date
20260506
Application Date
20210325

Claims (14)

  1. Polymer dispersion containing (a) 10 to 70 parts by weight of copolymers, the units of which are derived from (a1) 50% to 99.9% by weight of one monomer or multiple monomers from the group of the alkyl (meth)acrylates having the general formula (1): where R = C n H 2n+1 with n ≥ 16 and R' = CH 3 or H; (a2) 0.1% to 10% by weight of ethylenically unsaturated monocarboxylic acids, dicarboxylic acids, or salts thereof or acid anhydrides thereof; (a3) 0% to 49.9% by weight of one monomer or multiple monomers from the group of the alkyl (meth)acrylates of the general formula (2): where R" = C n H 2n+1 with n = 8 to 15 and R' = CH 3 or H; (a4) 0% to 30% by weight of one monomer or multiple monomers selected from the group consisting of (meth)acrylamide, N-alkyl(meth)acrylamides or N,N-dialkyl(meth)acrylamides where alkyl = C n H 2n+1 wherein n can be between 1 and 60, N-vinylpyrrolidone, 2-vinylpyridine, 4-vinylpyridine, styrene, vinyl acetate, isobornyl (meth)acrylate, tert-butyl (meth)acrylate, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, cyclohexyl (meth)acrylate, isohexyl (meth)acrylate, n-hexyl (meth)acrylate, benzyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, 2-dimethylaminoethyl (meth)acrylate, 2-diethylaminopropyl methacrylate, 3-dimethylaminopropyl(meth)acrylamide, trimethylaminopropyl (meth)acrylate chloride, 3-trimethylammoniopropyl(meth)acrylamide chloride, hydroxyethylethylurea (meth)acrylate, N-methylol(meth)acrylamide, polyalkylene glycol ether (meth)acrylates of the general formula (3), hydroxyethyl (meth)acrylate phosphate, an alkyl (meth)acrylate of the general formula (2) but with radical R" with n < 8; where n = 1 to 200; R' = CH 3 or H; R‴ = C m H 2m+1 with m = 1 to 30; Rʺʺ = CH 3 or H; (b) 0.5 to 20 parts by weight of an emulsifier system consisting of at least two different emulsifiers from the group of the sulfosuccinates independently selected from the group consisting of sodium bis(2-ethylhexyl) sulfosuccinate, sodium bistridecyl sulfosuccinate, sodium bisisooctyl sulfosuccinate, sodium biscyclohexyl sulfosuccinate, sodium bisoctyl sulfosuccinate, sodium diamyl sulfosuccinate, sodium diisobutyl sulfosuccinate, sodium dihexyl sulfosuccinate, disodium lauryl sulfosuccinate, disodium salt of ethoxylated nonylphenol sulfosuccinate, disodium ethylhexyl sulfosuccinate, and disodium N-octadecyl sulfosuccinate; (c) 1 to 40 parts by weight of a water-miscible cosolvent or a mixture of multiple water-miscible cosolvents; (d) 0 to 20 parts by weight of one or more further emulsifiers which do not belong to the group of the sulfosuccinates; (e) 0 to 20 parts by weight of further components and (f) water to 100 parts by weight.
  2. Polymer dispersion according to Claim 1, wherein the emulsifier system contains a sulfosuccinate having at least one C 10 to C 15 alkyl radical and also a further sulfosuccinate having at least one C <10 alkyl radical.
  3. Polymer dispersion according to Claim 1 or 2, wherein the at least two different emulsifiers are dialkyl sulfosuccinates in each case.
  4. Polymer dispersion according to any one of the preceding claims, wherein the emulsifier system contains sodium bis(2-ethylhexyl) sulfosuccinate and sodium bistridecyl sulfosuccinate.
  5. Polymer dispersion according to Claim 4, wherein sodium bis(2-ethylhexyl) sulfosuccinate and sodium bistridecyl sulfosuccinate are used in the ratio of 1:10 to 10:1.
  6. Polymer dispersion according to any one of the preceding claims, wherein the monomer from the group of the alkyl (meth)acrylates is behenyl (meth)acrylate and/or wherein the unsaturated monocarboxylic acids, dicarboxylic acids, or salts thereof or acid anhydrides thereof are (meth)acrylic acid and derivatives thereof.
  7. Polymer dispersion according to any one of the preceding claims, wherein the water-miscible cosolvent(s) is/are selected from the group consisting of short-chain alcohols, dialcohols, trialcohols, glycols and glycol ethers, ketones, and ethers.
  8. Polymer dispersion according to any one of the preceding claims, wherein the further emulsifier(s) (d) is/are selected from the group of the water-in-oil emulsifiers (W/O emulsifiers) or mixtures of these emulsifiers preferably having a Griffin HLB value of less than 9 or mixtures yielding together an HLB value of less than 9.
  9. Process for preparing a polymer dispersion according to any one of Claims 1 to 8 by free-radical emulsion polymerization in water in the presence of at least one cosolvent and in the presence of an emulsifier system comprising at least two different emulsifiers from the group of the sulfosuccinates.
  10. Process according to Claim 9, wherein initiators selected from the group consisting of peroxides, organic hydroperoxides, peracids and peroxodisulfates are used for the free-radical emulsion polymerization.
  11. Process according to Claim 9 or 10, wherein at least one chain transfer agent selected from the group of the alkyl mercaptans is used for the free-radical emulsion polymerization.
  12. Process according to any one of Claims 9 to 11, wherein the polymerization reaction is carried out at a temperature of 20°C to 100°C and/or wherein a buffer substance is added.
  13. Process according to any one of Claims 9 to 12, wherein an emulsifier selected from the group of the water-in-oil emulsifiers (W/O emulsifiers) or mixtures of these emulsifiers preferably having a Griffin HLB value of less than 9 or mixtures yielding together an HLB value of less than 9 is added after completion of the polymerization.
  14. Use of polymer dispersions according to any one of Claims 1 to 8 for inhibiting the deposition of paraffins in crude mineral oils and/or for reducing the pour point of crude mineral oils.

Description

Field of the invention The invention, as defined in the appended claims, relates to polymer dispersions made from (meth)acrylates having long side chains that can be used as paraffin inhibitors and have good low-temperature applicability here. Prior art Flow aids are commonly used to improve the flow properties of crude oils and/or mineral oil fractions. They are especially necessary for allowing the flowability of the oil even at low temperatures, at which the untreated oil is already solid or viscous as a result of precipitation or crystallization of dissolved solid constituents, such as longer-chain paraffins and/or asphaltenes, or solid deposits occur which, for example, lead to a narrowing of the pipelines. Here, the flow aid can lower the pour point of the (crude) oil, and this prevents solidification of the oil below a certain temperature. In this case, the flow improver acts as a co-called pour point depressant. Furthermore, the flow aid can lead to an inhibition or reduction of paraffin deposits on (cold) surfaces (e.g., the inner wall of pipelines). In this case, the flow aid acts as a so-called paraffin inhibitor. One or else both of these properties may be important, depending on the (crude) oil. The performance of a flow aid is to be rated according to its ability to shift the pour point of the oil to lower temperatures and/or its ability to reduce the amount of deposited wax on (cold) surfaces. Polymers which have long side chains (i.e. alkyl side chains ≥ C16) and act as crystallization inhibitors by cocrystallization with the longer-chain paraffins are commonly used as flow aids. The aforementioned polymers are commonly (co)polymers of (meth)acrylates having long side chains of the general formula (1) where R = CnH2n+1 with n ≥ 16 and R' = CH3 or H. Since such polymers are present as solids at the customary use temperatures, but must be distributed as homogeneously as possible in the oil in the end use, they are customarily used as solutions in organic solvents, usually in aromatic organic solvents. Besides the negative properties due to said organic solvents such as flammability and toxicity, such polymer solutions have further disadvantages. For instance, the flow aids themselves are not pourable at low temperatures owing to the side-chain crystallization of the polymers, and this hampers or prevents metering at low temperatures into the oil to be treated. To counteract this problem, either the tank farms and supply lines for metering the flow aid can be heated, this being associated with high energy costs, or the inherent pour point of the flow aid can be lowered in a certain range by further dilution with organic solvent to < 10% active content. This however likewise being associated with high additional costs (solvent costs, transport costs, greater need of storage space, additional safety measures due to the flammability of the solvents). To circumvent this problem, polymer dispersions in a continuous phase (e.g. water or mixtures of water with a water-miscible solvent) can be used instead of polymer solutions in organic solvents. The advantage of this is that the viscosity and the flow behaviour of the formulation are hardly dependent on the properties and the amount of the polymer in the disperse phase, but are instead substantially dependent on the properties of the continuous phase. This allows, firstly, the use of highly concentrated formulations which can be pumped to their site of use without any problems owing to their low viscosity even at very low temperatures. Secondly, when selecting the polymers, the solubility behaviour thereof in organic solvents need not be heeded; instead, when selecting the polymers, it is possible to focus more on the performance as flow improver. The laid-open specifications WO9833846 A1, US20100025290 A1 and WO2019057396 A1 describe the preparation of such dispersions in the form of a secondary dispersion. This is a multistage process in which polymerization in organic solvent takes place first of all, followed by dispersion into a continuous phase. To generate the secondary dispersion with small particle sizes, what is necessary here is a high degree of shearing (e.g. via Ultraturrax, high-pressure homogenizer, ultrasound) in order to achieve a sufficient stability of the dispersions, this being complicated on an industrial scale. Where appropriate, it is moreover necessary at the end to distil off the organic solvent. WO2019048663A1 and WO2017153462A1 describe the preparation of such dispersions via a so-called mini-emulsion polymerization. In this case, very small monomer droplets are formed before the actual polymerization with the aid of high shear rates (e.g. ultrasound treatment or high-pressure homogenization) in an aqueous phase, which are then subsequently converted to polymer particles by polymerization. However, such a process can only be implemented with difficulty on an industrial scale and is moreover very costly. A further possibil