JP2001525867A - Polymer composition - Google Patents

Abstract

  (57) [Summary] Aliphatic containing at least 10 carbon atoms obtained by polymerization of at least one olefinically unsaturated compound in a continuous aqueous phase containing at least one polymer B containing a thixotropic hydrophilic polymer and a surfactant. A polymer composition comprising a dispersion of at least one polymer A having hydrocarbon side chains, a process for the preparation of this composition and its use as pour point depressant.

Description

The present invention relates to polymer compositions, their preparation, and their use as pour point depressants. Crude oil (crude mineral oil) and certain fuels derived therefrom (oils), such as wax-containing fuel oils and diesel fuels, can contain significant amounts of wax. When such materials are cooled, the wax gradually separates, and at sufficiently low temperatures, the materials solidify completely. The lowest temperature at which a waxy material is still flowable as found in a standard laboratory test (ASTM D.97) is referred to as the "pour point" of the material. In order to overcome the problems encountered during cooling in storage or transportation of such materials in tankers and pipelines, certain polymers have been developed and added to such materials to lower the pour point of the material. I have. Such polymers are typically those obtained by the polymerization of at least one olefinically unsaturated compound, the polymer being at least 10%, such as, for example, a C ₁₀ -C ₃₀ aliphatic hydrocarbon side chain. Has an aliphatic hydrocarbon side chain having three carbon atoms. Typically, these polymers have molecular weights ( _Mn ) in the range of 10,000 to 1,000,000. Examples of such polymers include UK Patent Application No. 1154966, UK Patent Application No. 116118, UK Patent Application No. 1285087, UK Patent Application No. 1410819, European Patent Application No. 012 0512, European Patent Application No. 0236844. And U.S. Patent Application No. 4457202. Although these polymers are very effective as pour point depressants, and thus have proven to be useful flow improvers, they are typically used as concentrates in solvents such as toluene or xylene. As sold, this solution can itself have a relatively high pour point. For the distribution of crude or fuel oil in tanks, this is normally present without any problems. Examples of commercially available flow improvers include a 50% by weight solution of an alkyl acrylate polymer in xylene as solvent sold by Royal Dutch / Shell Group under the trademark "SHELLSWIM-5X" (pour point 27 ° C.), and a 50% by weight solution of an alkyl acrylate / vinyl pyridine copolymer in toluene (having a pour point of 18 ° C.) sold under the trademark “Shell Swim-11T”. However, if it is desirable to pass the flow improver itself along a pipeline located in a cold environment, such as the North Sea or the Arctic, pour points that readily maintain flow at low environmental temperatures It would be advantageous to have a concentrated formulation of a depressant. In European Patent Application 0448166 it is disclosed that the concentrate formulation contains an alkyl acrylate polymer, a surfactant, a polyol and various amounts of water. It is clear from the patent that the best results (long-term storage stability) are obtained when preparing and using formulations containing limited amounts of water. Surprisingly, it has been found that formulations containing high amounts of water constitute an attractive pour point depressant when containing a thixotropic hydrophilic polymer. In the present invention, it is obtained by polymerization of at least one olefinically unsaturated compound in a continuous aqueous phase containing a surfactant and at least one polymer B containing a thixotropic hydrophilic polymer. And a polymer composition comprising a dispersion of at least one polymer A having an aliphatic hydrocarbon side chain containing at least 10 carbon atoms. The polymer compositions of the present invention advantageously exhibit low viscosity under transport conditions and long term storage stability. Suitable polymers A are disclosed in British Patent Application No. 1154966, British Patent Application No. 116118, British Patent Application No. 1285087, European Patent Application No. 0120512, European Patent Application No. 0236844 and U.S. Patent Application No. ing. These polymers are typically molecular weight (M _n) in the range of 10,000 to 1,000,000, and having a C ₁₀ -C ₃₀ aliphatic hydrocarbon side chain. Preferred polymers A have a molecular weight ( _Mn ) in the range of 20,000 to 250,000, more preferably 25,000 to 100,000, for example 30,000 to 80,000. Polymer A is preferably a homo- or copolymer of one or more (C _18-30 n-alkyl) acrylates or methacrylates, such as 1-dodecyl acrylate (C ₂₂ ), 1-octadecyl acrylate (C ₁₈ ) and 1-eicosyl acrylate (C ₂₀ ). Suitable copolymers are monoolefinically unsaturated compounds having nitrogen-containing groups, such as acrylonitrile, acrylamide, p-aminostyrene, N-vinylpyrrolidone or 4-vinylpyridine, and one or more (C _18-30 n-alkyl) acrylate or methacrylate copolymers. Most preferred polymer A is a polymer of one or more (C _18-26 n-alkyl) acrylates or a copolymer of one or more (C _18-26 n-alkyl) acrylates and 4-vinylpyridine. Various nonionic and ionic surfactants are suitable for incorporation into the compositions of the present invention. Preferably, these surfactants are selected from ethoxy sulfate alcohol surfactants or lignosulfonate surfactants. Such surfactants are typically alkali metal or ammonium salts. Ethoxy sulfate alcohol surfactants typically have the _{formula: RO- (CH 2 CH 2 O} ) n -SO 3 -M ( wherein, m is sodium or ammonium, R represents C _12-18 alkyl And n is 2 or 3.). The composition of the present invention suitably comprises 0.1 to 20, preferably 1 to 15, more preferably 1 to 10 parts by weight of surfactant per 100 parts by weight of polymer A. Polymer B comprises a thixotropic hydrophilic polymer. Such polymer solutions have been found to have high viscosities at low shear rates and low viscosities at high shear rates. Suitable polymers B include, for example, polysaccharides (eg, xanthan gum) and partially hydrated polyacrylamide. These polymers typically have a number average molecular weight ( _Mn ) in the range of 1 × 10 ⁵ to 1 × 10 ⁷ , preferably in the range of 5 × 10 ⁵ to 5 × 10 ⁶ . Suitably, these polymers have a molecular weight distribution ( _Mw / _Mn , where _Mw is defined as the weight average molecular weight) of 1 to 5, preferably 1 to 2, most preferably 1 to 1.5. Range. Polymer B is preferably a polysaccharide. The most preferred polymer B is xanthan gum. The composition of the present invention suitably contains 0.01 to 20, preferably 0.1 to 10, and more preferably 0.2 to 5 parts by weight of polymer B per 100 parts by weight of polymer A. These amounts include a small amount of a solvent, such as ethanol, that may be present in the surfactant selected to mix into the composition. Small amounts of other additives such as antioxidants, corrosion inhibitors or metal deactivators may be incorporated into the compositions of the present invention. The composition of the present invention suitably contains 20 parts by weight or more of water, preferably 50 parts by weight or more, more preferably 80 parts by weight or more based on 100 parts by weight of the polymer A. The presence of the thixotropic polymer, even in small amounts, has a beneficial effect on reducing viscosity under transport conditions. A suitable continuous aqueous phase can contain two or more different types of thixotropic hydrophilic polymers. The present invention further provides a process for preparing the polymer composition of the present invention, the process comprising emulsifying a mixture of polymer A, a surfactant and polymer B at a temperature above the melting point of polymer A, the resulting emulsion. Cooling the liquid to a temperature below the melting point of Polymer A. The upper temperature limit of the process is determined by the lowest decomposition points of the various components of the mixture. It has been found to be very effective to use an acrylate polymer as polymer A, an ethoxysulfate alcohol surfactant and / or a lignosulfonate surfactant and emulsify the mixture at a temperature in the range of 50-100 ° C. And a temperature of 60-100 ° C is preferred. The present invention further provides for the use of the compositions of the present invention in lowering the pour point of crude mineral oils or wax-containing fuel oils or diesel oils. The polymer compositions of the present invention are particularly useful in the applications of the present invention in preventing and / or reducing wax deposition in crude oil pipelines. The fact that the aqueous composition is liquid at lower temperatures than a single solution of the relevant polymer at a corresponding concentration in a solvent such as toluene or xylene, makes it easier to handle in cold environments. Brings significant improvement in terms. Furthermore, since the present aqueous formulations contain little or no such solvents, they constitute a very favorable material compared to conventional formulations from a safety point of view. The present invention will be further understood by the following illustrative examples. In the examples, polymer I was prepared by gel permeation chromatography (GPC) (polyacrylate scale) prepared from a blend of linear alkyl acrylates including 1-dodecyl acrylate, 1-octadecyl acrylate and 1-eicosyl acrylate. An alkyl acrylate polymer having a measured molecular weight (M _n ) in the range of 49,000 to 76,000 and a melting point of 51 ° C. “DOBANOL 25-3A / 60” ™ ethoxysulfate is a 60% by weight solution of ammonium ethoxysulfate (C _12-15 alcohol) containing 3 moles of ethylene oxide / mole in aqueous ethanol (2: 1 w / w) (the density at 20 ° C. is 1.04 kg / L). Examples 1-6 Stir water (44.6 g), "Dobanor 25-3A / 60" ethoxysulfate (5 g) and partially hydrated polyacrylamide (PHAM) (0.4 g) in a 150 ml beaker, A homogeneous solution was obtained at room temperature (20 ° C.). Polymer I (50 g) was added and the bottle was placed in a constant temperature oil bath at 80 ° C. The two-layer mixture was emulsified for 1 minute using an “Ultralux T25” ™ laboratory emulsifier (1.8 cm disperser, 24,000 rpm). The obtained emulsion of Polymer I in the aqueous phase was taken out of the oil bath, cooled, and air-cooled to room temperature (20 ° C.) to obtain a desired composition as a free-flowing suspension. Another suspension (Examples 2-6) was prepared as in Example 4 except that xanthan gum was used instead of PHAM and hexadecyltrimethyl ammonium bromide (HDTMA B) was used instead of ethoxysulfate. In Comparative Example 5, glycerol was used in place of PHAM, the temperature of the thermostatic oil bath was set to 96 ° C., and the mixture was emulsified for 2 minutes; and in Comparative Example 6, PHAM was used instead of PHAM. The temperature of the constant temperature oil bath was adjusted to 101 ° C., and the mixture was slowly emulsified for 1 minute, and then water was added. Details of all six suspensions and their preparation are given in Table I. In each case, the suspension was stable at room temperature (20 ° C.) for at least one month. All of these suspensions were liquid at least down to 5 ° C. These suspensions were tested by adding Far East crude and evaluating the pour point according to ASTM D.97. The pour point of the undoped crude was 24 ° C. for Examples 1-3, while it was 30 ° C. for Examples 4-6. The test results for the suspensions of Examples 1 to 6 are summarized in Table II. Viscosity was measured at 20 ° C. on a Carri-Med “CSL 500” rheometer using a cone and plate system. From Table II, it can be seen that the suspensions of the invention (Examples 1-4) show an attractive flow with improved low viscosity when compared to suspensions outside the scope of the invention (Examples 5 and 6). It will be clear that points are shown.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme court ゛ (Reference) C10L 1/22 C10L 1/22 CA (81) Designated country EP (AT, BE, CH, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE), OA (BF, BJ, CF, CG, CI, CM, GA, GN, ML, MR, NE, SN, TD, TG), AP (GH, KE, LS, MW, SD, SZ, UG), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, CA, CH, CN, CU, CZ, DE, DK, EE, ES, FI, GB, GE, GH, HU, IL , IS, JP, KE, KG, KP, KR, KZ, LC, LK, LR, LS, LT, LU, LV, MD, MG, MK, MN, MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI, SK, TJ, TM, TR, TT, UA, UG, UZ, VN, YU Bad Heissweg 3

Claims (1)

[Claims] 1. In a continuous aqueous phase containing at least one polymer B containing a thixotropic hydrophilic polymer and a surfactant, at least 10 carbon atoms obtained by polymerization of at least one olefinically unsaturated compound. A polymer composition comprising a dispersion of at least one polymer A having an aliphatic hydrocarbon side chain. 2. 2. The polymer composition according to claim 1, wherein the at least one polymer B is a polysaccharide or a partially hydrated polyacrylamide. 3. The composition according to claim 1 or 2, wherein the molecular weight ( _Mn ) of the polymer A is in the range of 20,000 to 250,000. 4. The composition according to any one of claims 1 to 3, comprising 0.1 to 20 parts by weight of a surfactant per 100 parts by weight of the polymer A. 5. The composition according to any one of claims 1 to 4, comprising 0.01 to 20 parts by weight of polymer B per 100 parts by weight of polymer A. 6. 6. The composition according to claim 1, comprising more than 20 parts by weight of water per 100 parts by weight of polymer A. 7. Polymer A is a polymer of one or more (C _18-26 n-alkyl) acrylates or a copolymer of one or more (C _18-26 n-alkyl) acrylates and 4-vinylpyridine. A composition according to any one of claims 1 to 6. 8. The composition according to any one of claims 1 to 7, wherein the surfactant is an ethoxy sulfate alcohol surfactant or a lignosulfonate surfactant. 9. 9. The method according to claim 1, further comprising emulsifying a mixture of the polymer A, the surfactant and the polymer B at a temperature higher than the melting point of the polymer A, and cooling the obtained emulsion to a temperature lower than the melting point of the polymer A. A method for producing the composition according to any one of the preceding claims. Ten. Use of the composition according to any one of claims 1 to 8, which lowers the pour point of crude mineral oil or wax-containing fuel oil or diesel oil.