Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2/00—Processes of polymerisation
  • C08F2/12—Polymerisation in non-solvents
  • C08F2/16—Aqueous medium
  • C08F2/22—Emulsion polymerisation
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F218/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an acyloxy radical of a saturated carboxylic acid, of carbonic acid or of a haloformic acid
  • C08F218/02—Esters of monocarboxylic acids
  • C08F218/04—Vinyl esters
  • C08F218/08—Vinyl acetate
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B24/00—Use of organic materials as active ingredients for mortars, concrete or artificial stone, e.g. plasticisers
  • C04B24/24—Macromolecular compounds
  • C04B24/26—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • C04B24/2623—Polyvinylalcohols; Polyvinylacetates
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  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B24/00—Use of organic materials as active ingredients for mortars, concrete or artificial stone, e.g. plasticisers
  • C04B24/24—Macromolecular compounds
  • C04B24/26—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • C04B24/2641—Polyacrylates; Polymethacrylates
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  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B24/00—Use of organic materials as active ingredients for mortars, concrete or artificial stone, e.g. plasticisers
  • C04B24/24—Macromolecular compounds
  • C04B24/26—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • C04B24/2682—Halogen containing polymers, e.g. PVC
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
  • C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
  • C04B28/14—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing calcium sulfate cements
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
  • C04B28/24—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing alkyl, ammonium or metal silicates; containing silica sols
  • C04B28/26—Silicates of the alkali metals
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F18/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an acyloxy radical of a saturated carboxylic acid, of carbonic acid or of a haloformic acid
  • C08F18/02—Esters of monocarboxylic acids
  • C08F18/04—Vinyl esters
  • C08F18/08—Vinyl acetate
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2/00—Processes of polymerisation
  • C08F2/01—Processes of polymerisation characterised by special features of the polymerisation apparatus used
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2/00—Processes of polymerisation
  • C08F2/12—Polymerisation in non-solvents
  • C08F2/16—Aqueous medium
  • C08F2/22—Emulsion polymerisation
  • C08F2/24—Emulsion polymerisation with the aid of emulsifying agents
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L31/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an acyloxy radical of a saturated carboxylic acid, of carbonic acid or of a haloformic acid; Compositions of derivatives of such polymers
  • C08L31/02—Homopolymers or copolymers of esters of monocarboxylic acids
  • C08L31/04—Homopolymers or copolymers of vinyl acetate
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
  • C04B2103/0045—Polymers chosen for their physico-chemical characteristics
  • C04B2103/0057—Polymers chosen for their physico-chemical characteristics added as redispersable powders
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
  • C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
  • C04B2111/00482—Coating or impregnation materials
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
  • C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
  • C04B2111/00663—Uses not provided for elsewhere in C04B2111/00 as filling material for cavities or the like
  • C04B2111/00672—Pointing or jointing materials

Definitions

• the invention relates to a process for the preparation of aqueous polymer dispersions by means of free-radically initiated emulsion polymerization of ethylenically unsaturated monomers in the presence of protective colloids and / or emulsifiers in a continuously operated tubular reactor, and the use of the process products obtained therewith.
• Aqueous polymer dispersions are used as binders in a wide range of applications, for example in adhesives,
• aqueous dispersions are usually prepared by aqueous emulsion polymerization in stirred batch reactors or also continuous stirred tank cascades, as described in EP 1 323 752 B1.
• the process efficiency is limited by the dissipation of the released heat via cooling surfaces, for example cooling coils and reactor wall. For this reason, there have been repeated investigations into transferring the process from stirred kettles to tubular reactors without internals in order to benefit from the greater surface to volume ratio and correspondingly better cooling. Unfortunately, this shows that with a correspondingly narrow tube cross-section, these tube reactors quickly become clogged by deposits, known as fouling (polymer fouling), and the system operating time is drastically reduced.
• tubular reactors with built-in stirrers were used. But even here polymer fouling cannot be avoided and limits the availability of the system. This polymer fouling also occurs in traditional stirred tanks, but the impairment of the system availability is not as serious as with tubular reactors due to the smaller cooling surface and changed reactor geometry. In stirred kettles, one helps to slow down the build-up of deposits by coating the surfaces with antifouling agents, as described in EP 3 256 497 B1. In However, this effect is not sufficient for tubular reactors. In DE-AS 1137216, a tubular reactor is described with a stirrer or scraper that goes through the wall. With this procedure, the wall covering is not avoided, but mechanically removed by a subsequent measure.
• the object was to provide an improved process for the production of aqueous polymer dispersions that at the same time ensures high plant availability with high space-time performance (process efficiency).
• the invention relates to a process for the preparation of aqueous polymer dispersions by means of free-radically initiated emulsion polymerization of ethylenically unsaturated monomers in the presence of protective colloids and / or emulsifiers in a continuously operated tubular reactor, characterized in that the flow direction of the reactor contents (polymerization mixture) along the longitudinal axis of the reactor at regular time intervals is reversed.
• the process according to the invention can in principle be applied to all reactors with a pipe-like geometry.
• This includes, for example, stirred tubular reactors, unstirred tubular reactors, tubular reactors with internals such as static mixing elements, and also Taylor reactors with a cylindrical stirrer. Stirred tubular reactors are preferred.
• the tubular reactor preferably has a cylindrical geometry.
• the tubular reactor is largely characterized by the ratio of length to diameter.
• the ratio of length to diameter is preferably from 8: 1 to 40: 1, particularly preferably from 10: 1 to 25: 1.
• With smaller ratios one approaches too closely the Geometry of traditional stirred kettles, with strong back-mixing of the medium to be reacted. With larger values, the reactor becomes very long, which limits the practical implementation, since the tubular reactor is preferably vertical and is limited by the building dimensions.
• the tubular reactor can - viewed in the longitudinal direction or in the flow direction - be stored vertically, horizontally or in a position between these two directions.
• the longitudinal direction of the tubular reactor is generally the distance from the reactor bottom to the reactor cover. Vertical storage is preferred. If the tubular reactor is not mounted horizontally, the reaction medium can flow through it with gravity from top to bottom or, preferably, against gravity from bottom to top.
• a stirred tubular reactor can use any stirrer technology, preferably single-dimensioned paddle stirrers are used as stirring elements.
• the speed of the stirrer depends on the overall dimensions of the reactor and is between 200 and 2000 revolutions per minute, preferably between 500 and 1500 revolutions per minute.
• One revolution stands for one revolution of the stirrer around its longitudinal axis or around the axis that is parallel to the direction of flow.
• the stirrer can be driven in a conventional manner, for example via a mechanical gear, and sealed via a magnetic coupling or a mechanical seal.
• the mean residence time of the polymerization mixture in the tubular reactor is generally from 10 minutes to 5 hours, preferably from 15 minutes to 2 hours, particularly preferably from 20 minutes to 1 hour and most preferably from 25 minutes to 45 minutes.
• the mean residence time can be set, for example, via the metering speed or the dimensions of the tubular reactor.
• the direction of flow of the tubular reactor contents is reversed at a time interval (time interval) of 60 minutes to 48 hours, particularly preferably the direction of flow is reversed at a time interval (time interval) of 6 hours to 12 hours.
• a tubular reactor for carrying out the process according to the invention is shown in FIG. 1 as a tubular reactor (1).
• the embodiment in FIG. 1 is purely illustrative for explaining the method and in no way restrictive for the present invention.
• the tubular reactor (1) in which the polymerization takes place is constructed from a steel tube, preferably a jacketed tube (2), which has an axially arranged agitator shaft (3) inside which is equipped with several agitator elements (4).
• the tubular reactor (1) is equipped with a metering line (5) which is connected to an upstream mixing unit (6) for mixing the starting materials.
• the tubular reactor (1) is connected via a withdrawal line (7) to a downstream container (8) in which the polymerization product is collected and, if necessary, after-treated.
• the starting materials can be introduced into the tubular reactor (1), preferably continuously, via the metering line (5).
• the polymerization product can be discharged from the tubular reactor (1), preferably continuously, through the withdrawal line (7).
• additional metering devices (9a) to (9e) further substances, preferably initiators, can be fed to the tubular reactor along the tubular reactor.
• the procedure can be such that the educt mixture (pre-emulsion) from the mixing unit (6) via the branch (5a) of the metering line (5) and via the open valve (10) to the tubular reactor (1) is supplied.
• the polymerisation product is fed to the container (8) via the opened valve (11) and the section (7a) of the removal line (7).
• the valve (12) and the valve (13) are closed in this phase of operation.
• valves (10) and (11) are closed, and then valve (12) and valve (13) are opened.
• the educt mixture is discharged from the mixing unit (6) via the branch (5b) of the metering line (5) via the open Valve (12) fed to the tubular reactor (1), and the polymerisation product removed via the now open valve (13) and fed to the container (8) via section (7b) of the removal line (7).
• valves (12) and (13) are closed and valves (10) and (11) are opened again.
• the polymerization takes place according to the emulsion polymerization process in an aqueous medium, preferably no organic solvents are used.
• the polymerization temperature of the polymerization mixture in the tubular reactor is preferably between 40.degree. C. and 120.degree. C. and particularly preferably between 50.degree. C. and 110.degree.
• the pressure in the tube reactor depends on whether the monomers to be polymerized are liquid or gaseous at the respective polymerization temperature and is preferably 1 to 110 bar abs. In the copolymerization of gaseous comonomers such as ethylene, 1,3-butadiene or vinyl chloride, under Pressure, and particularly preferably at 10 to 80 bar abs . polymerized.
• the constituents of the reaction mixture can be mixed beforehand in a mixing unit and fed continuously to the tubular reactor.
• the constituents of the reaction mixture are preferably mixed continuously in a mixing unit to form a pre-emulsion and this is transported into the tubular reactor.
• the procedure is preferably such that no oxidation catalyst is added to the pre-emulsion.
• the procedure is preferably such that the reduction initiator is added to the pre-emulsion and the oxidation initiator is preferably added to the tubular reactor.
• the transport takes place by means of pumps or via the pure mass flow when the mixing unit is completely filled.
• the mixing unit can be, for example, a stirred tank or a static mixing section.
• the mixing unit can be provided with a double jacket in order to cool or heat, if necessary, during mixing.
• the starting materials can be tempered before being introduced into the tubular reactor.
• the starting materials must be kept at a temperature between 10 ° C. and the polymerization temperature.
• a mixture pre-emulsion
• the aforementioned mixtures are preferably heated to a temperature between the polymerization temperature and 20 ° C. below the polymerization temperature, in particular to 10 ° C.
• Initiators in particular oxidation initiators, are particularly preferably added to a mixture heated in this way directly before entry into the tubular reactor or metered directly into the tubular reactor.
• the temperature control can take place before, during or after their thorough mixing. Common heat exchangers can be used for this purpose.
• the tube reactor can be tempered with common cooling and / or heating devices, such as jacket coolers or jacket heaters. Cooling and / or heating devices can, for example, be attached to the tubular reactor on the wall or to built-in cooling coils.
• the outer reactor wall can be provided with a cooling or heating jacket (double-jacket tube), the intermediate space of which is traversed by a temperature control liquid.
• a tubular reactor with a jacketed tube is preferably used.
• the tubular reactor is preferably filled with a polymer dispersion which preferably corresponds to the end product of the polymerization in terms of polymer composition, type and amount of protective colloid, and particle size and solids content.
• a polymer dispersion which preferably corresponds to the end product of the polymerization in terms of polymer composition, type and amount of protective colloid, and particle size and solids content.
• the tubular reactor can be filled with a mixture which comprises the starting materials but no initiators, in particular no oxidation initiators.
• the tubular reactor must be filled with water, preferably exclusively with water, before the start of the process according to the invention.
• the tubular reactor is generally operated continuously.
• the starting materials in particular ethylenically unsaturated monomers, protective colloids and / or emulsifiers and / or initiators, are introduced into the tubular reactor during the emulsion polymerization and the polymerization product is removed from the tubular reactor.
• the entering mass flows should correspond to the exiting mass flows.
• the polymerization is generally carried out up to a conversion of at least 85% by weight, preferably up to a conversion of 90 to 99% by weight, of the monomers which are liquid under polymerization conditions.
• the polymerization product is then transferred to a collecting tank (expansion tank).
• the transport takes place by means of pumps or due to the pressure difference between the tubular reactor and the collecting tank.
• Post-polymerization can optionally be carried out in the collecting tank using known methods, for example by post-polymerization initiated with a redox catalyst.
• the volatile residual monomer content is then optionally removed by passing over or preferably passing inert entrainment gases such as air, nitrogen or preferably water vapor over / through the aqueous polymerization mixture in a manner known to the person skilled in the art (stripping).
• inert entrainment gases such as air, nitrogen or preferably water vapor over / through the aqueous polymerization mixture in a manner known to the person skilled in the art (stripping).
• the polymerization product is removed from the collecting tank and stored in a silo, for example.
• the ethylenically unsaturated monomers are preferably selected from the group comprising vinyl esters, (meth) acrylic acid esters, vinyl aromatics, olefins, 1,3-dienes and vinyl halides and optionally other monomers copolymerizable therewith.
• Suitable vinyl esters are those of carboxylic acids having 1 to 18 carbon atoms.
• Vinyl acetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate, vinyl laurate, 1-methyl vinyl acetate, vinyl pivalate and vinyl esters of alpha-branched monocarboxylic acids with 9 to 11 carbon atoms are preferred Atoms, for example VeoVa9 ® or VeoVa10 ® (trade names of Hexion).
• Vinyl acetate is particularly preferred.
• Suitable monomers from the group of acrylic acid esters or methacrylic acid esters are, for example, esters of unbranched or branched alcohols having 1 to 15 carbon atoms.
• Preferred methacrylic acid esters or acrylic acid esters are methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, n-butyl acrylate, n-butyl methacrylate, t-butyl acrylate, t-butyl methacrylate, 2-ethylhexyl acrylate.
• Methyl acrylate, methyl methacrylate, n-butyl acrylate, t-butyl acrylate and 2-ethylhexyl acrylate are particularly preferred.
• Preferred vinyl aromatics are styrene, methyl styrene and vinyl toluene.
• the preferred vinyl halide is vinyl chloride.
• the preferred olefins are ethylene, propylene and the preferred dienes are 1,3-butadiene and isoprene.
• auxiliary monomers can also be copolymerized. It is preferred to use from 0.1 to 5% by weight of auxiliary monomers.
• auxiliary monomers are ethylenically unsaturated mono- and dicarboxylic acids, preferably acrylic acid, methacrylic acid, fumaric acid and maleic acid; ethylenically unsaturated carboxamides and nitriles, preferably acrylamide and acrylonitrile; Mono- and diesters of fumaric acid and maleic acid such as the diethyl and diisopropyl esters and maleic anhydride; ethylenically unsaturated sulfonic acids or their salts, preferably vinyl sulfonic acid, 2-acrylamido-2-methyl-propane sulfonic acid.
• pre-crosslinking comonomers such as poly-ethylenically unsaturated comonomers, for example dialyl phthalate, divinyl adipate, diallyl maleate, allyl methacrylate or triallyl cyanurate, or post-crosslinking comonomers, for example acrylamidoglycolic acid (AGA), methyl acrylamido-methyl ester (AGA), methyl acrylamidoglycolate N-methylol methacrylamide, N-methylol allyl carbamate, alkyl ethers such as isobutoxy ether or esters of N-methylol acrylamide, N-methylol methacrylamide and N-methylol allyl carbamate.
• AGA acrylamidoglycolic acid
• AGA methyl acrylamido-methyl ester
• alkyl ethers such as isobutoxy ether or esters of N-methylol acrylamide, N-methylol methacrylamide
• Epoxy-functional comonomers such as glycidyl methacrylate and glycidyl acrylate are also suitable.
• Other examples are silicon-functional comonomers such as acryloxypropyltri (alkoxy) and methacryloxypropyltri (alkoxy) silanes, vinyltrialkoxysilanes and vinylmethyldialkoxysilanes, it being possible for example to contain ethoxy and ethoxypropylene glycol ether radicals as alkoxy groups.
• Monomers with hydroxy or CO groups may also be mentioned, for example methacrylic acid and acrylic acid hydroxyalkyl esters such as hydroxyethyl, hydroxypropyl or hydroxybutyl acrylate or methacrylate, and compounds such as diacetone acrylamide and acetylacetoxyethyl acrylate.
• One or more monomers are preferably selected from the group comprising vinyl esters; Vinyl ester mixtures containing several monomers from the group comprising vinyl esters, olefins, vinyl aromatics, vinyl halides, acrylic acid esters, methacrylic acid esters, fumaric and / or maleic acid mono- or diesters; (Meth) acrylic acid esters; (Meth) acrylic acid ester mixtures containing one or more monomers from the group comprising methacrylic acid esters, acrylic acid esters, olefins, vinyl aromatics, vinyl halides, fumaric and / or maleic acid mono- or diesters; Monomers or monomer mixtures of dienes such as butadiene or isoprene, and of olefins such as ethene or propene, it being possible for the dienes to be polymerized, for example, with styrene, (meth) acrylic esters or the esters of fumaric or maleic acid; Monomers or monomer mixtures
• Monomer mixtures of vinyl acetate with 1 to 50% by weight of ethylene are particularly preferred; Monomer mixtures of vinyl acetate with 1 to 50% by weight of ethylene and 1 to 50% by weight of one or more further comonomers from the group of vinyl esters with 3 to 12 carbon atoms in the carboxylic acid radical, such as vinyl propionate, vinyl laurate, vinyl esters of alpha-branched ones Carboxylic acids with 9 to 11 carbon atoms such as VeoVa9 ® , VeoValO ® ; Monomer mixtures of one or more vinyl esters, 1 to 50% by weight of ethylene and preferably 1 to 60% by weight of (meth) acrylic acid esters of unbranched or branched alcohols having 1 to 15 carbon atoms, in particular n-butyl acrylate.
• (Meth) acrylic acid ester monomer mixtures are particularly preferred, such as monomer mixtures of n-butyl acrylate or 2-ethylhexyl acrylate or copolymers of methyl methacrylate with n-butyl acrylate and / or 2-ethylhexyl acrylate; Styrene-acrylic acid ester monomer mixtures with one or more monomers from the group consisting of methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate; Vinyl acetate / acrylic acid ester monomer mixtures with one or more monomers from the group consisting of methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate and, if appropriate, ethylene; Styrene-1,3-butadiene monomer mixtures; where the mono
• Examples of particularly preferred comonomers for vinyl chloride monomer mixtures are ⁇ -olefins such as ethylene and propylene, vinyl esters such as vinyl acetate, acrylic acid esters and methacrylic acid esters of alcohols with 1 to 15 carbon atoms such as methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, n-butyl acrylate , t-butyl acrylate, n-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl acrylate, fumaric and maleic acid mono- or diesters such as the dimethyl and diethyl esters of maleic acid and fumaric acid.
• ⁇ -olefins such as ethylene and propylene
• vinyl esters such as vinyl acetate
• monomer mixtures with vinyl acetate and 5 to 50% by weight of ethylene Monomer mixtures with vinyl acetate and 1 to 50% by weight of ethylene and 1 to 50% by weight of a vinyl ester of -branched monocarboxylic acids having 9 to 11 carbon atoms; Monomer mixtures with 30 to 75% by weight of vinyl acetate, 1 to 30% by weight of vinyl laurate or a vinyl ester an ⁇ -branched carboxylic acid having 9 to 11 carbon atoms, and 1 to 30% by weight (meth) acrylic acid esters of unbranched or branched alcohols having 1 to 15 carbon atoms, which optionally also contain 1 to 40% by weight ethylene ; Monomer mixtures with vinyl acetate, 5 to 50 wt .-% ethylene and 1 to 60 wt .-% vinyl chloride; as well as monomer mixtures containing 60 to 98% by weight of vinyl chloride and 1 to 40% by weight of ethylene, the monomer mixtures each also being able to contain auxiliary monomers in the
• the selection of monomers and the selection of the proportions by weight of the comonomers are carried out in such a way that, in general, a glass transition temperature Tg of -50 ° C to + 50 ° C, preferably -20 ° C to + 30 ° C, results.
• the glass transition temperature Tg of the polymers can be determined in a known manner by means of differential scanning colorimetry (DSC).
• Tgn the glass transition temperature in Kelvin of the homopolymer of the monomer n. Tg values for homopolymers are given in Polymer Handbook 2nd Edition, JU. Wiley & Sons, New York (1975).
• the polymerization is initiated with the initiators customary for emulsion polymerization, in particular redox initiator combinations of oxidation initiator and reduction initiator.
• suitable oxidation initiators are the sodium, potassium and ammonium salts of peroxodisulfuric acid, hydrogen peroxide and azobisisobutyronitrile.
• the sodium, potassium and ammonium salts of peroxydisulfuric acid and hydrogen peroxide are preferred.
• the initiators mentioned are generally used in an amount of from 0.01 to 2.0% by weight, based on the total weight of the monomers.
• Suitable reducing agents are the sulfites and bisulfites of alkali metals and of ammonium, for example sodium sulfite; the derivatives of sulfoxylic acid such as zinc or Alkali formaldehyde sulfoxylates, for example sodium hydroxymethanesulfinate (Bruggolite) and ascorbic acid, isoascorbic acid or its salts, or formaldehyde-free reducing agents such as 2-hydroxy-2-sulfinato-acetic acid disodium salt (Bruggolite FF6).
• the amount of reducing agent is preferably 0.015 to 3% by weight, based on the total weight of the monomers.
• regulating substances can be used during the polymerization. If regulators are used, they are usually used in amounts between 0.01 and 5.0% by weight, based on the monomers to be polymerized. Examples of such substances are n-dodecyl mercaptan, tert. -Dodecylmer- captan, mercaptopropionic acid, ethyl mercaptopropionate, isopropanol and acetaldehyde. Preferably no regulating substances are used.
• Suitable protective colloids are partially saponified polyvinyl alcohols; Polyvinylpyrrolidones; Polyvinyl acetals; Polysaccharides in water-soluble form such as starches (amylose and amylopectin), celluloses and their carboxymethyl, methyl, hydroxyethyl, and hydroxypropyl derivatives; Proteins such as casein or caseinate, soy protein, gelatin, lignosulfonates; synthetic polymers such as poly (meth) acrylic acid, copolymers of (meth) acrylates with carboxyl-functional comonomer units, poly (meth) acrylamide, polyvinylsulfonic acids and their water-soluble copolymers; Melamine formaldehyde sulfonates, naphthalene formaldehyde sulfonates, styrene maleic acid and vinyl ether maleic acid copolymers; cationic polyvinyl alcohols; Polyvinylpyrrolidone
• Preferred protective colloids are partially saponified or fully saponified polyvinyl alcohols.
• Partially saponified polyvinyl alcohols with a degree of hydrolysis of 80 to 95 mol% and a Höppler viscosity, in 4% aqueous solution, of 1 to 30 mPas are particularly preferred.
• Partially saponified, hydrophobically modified polyvinyl alcohols with a degree of hydrolysis of 80 to 95 mol% and a Höppler viscosity of 4% are also particularly preferred iger aqueous solution, from 1 to 30 mPas.
• Examples of these are partially saponified copolymers of vinyl acetate with hydrophobic comonomers such as isopropenyl acetate, vinyl pivalate, vinyl ethylhexanoate, vinyl esters of saturated alpha-branched monocarboxylic acids with 5 or 9 to 11 carbon atoms, dialkyl maleate and dialkyl fumarates such as diisopropyl, vinyl fumarate ethers such as vinyl fumarate ethers, such as vinyl fumarate and diisopropyl chloride Vinyl butyl ether, olefins such as ethene and decene.
• the proportion of the hydrophobic units is preferably 0.1 to 10% by weight, based on the total weight of the partially saponified polyvinyl alcohol. Mixtures of the polyvinyl alcohols mentioned can also be used.
• polyvinyl alcohols with a degree of hydrolysis of 85 to 94 mol% and a Höppler viscosity, in 4% aqueous solution, of 3 to 15 mPas (Höppler method at 20 ° C., DIN 53015).
• the protective colloids mentioned are accessible or commercially available by means of processes known to the person skilled in the art.
• the protective colloids are generally added in the course of the polymerization in a total amount of 1 to 20% by weight, based on the total weight of the monomers.
• emulsifiers for example anionic and / or nonionic emulsifiers
• anionic emulsifiers are alkyl sulfates with a chain length of 8 to 18 carbon atoms, alkyl or alkylaryl ether sulfates with 8 to 18 carbon atoms in the hydrophobic radical and up to 40 ethylene oxide or propylene oxide units, alkyl or alkylaryl sulfonates with 8 to 18 C atoms, esters and half esters of sulfosuccinic acid with monohydric alcohols.
• nonionic emulsifiers are C12-C14 fatty alcohol ethoxylates with a degree of ethoxylation of 2 to 20 ethylene oxide units.
• the aqueous dispersions obtainable with the process according to the invention have a solids content of 30 to 75 wt. -%, preferably from 50 to 60 wt. -%.
• the aqueous dispersions can be used to produce polymer powders that are redispersible in water.
• the aqueous dispersions optionally after the addition of protective colloids as an atomizing aid, are dried by means of fluidized bed drying, freeze drying or, preferably, spray drying.
• aqueous polymer dispersions and the water-redispersible polymer powders can be used in the areas of application typical for them.
• binders such as cements, gypsum and water glass
• construction adhesives in particular tile adhesives and thermal insulation adhesives, plasters, leveling compounds, floor leveling compounds, leveling compounds, sealing slurries, grout and paints.
• binders for coating agents and adhesives or as coating agents or binders for textiles and paper are also as binders for coating agents and adhesives or as coating agents or binders for textiles and paper.
• the polymerization was carried out in a tubular reactor (1) with a length of 1600 mm and an internal diameter of 100 mm.
• the reactor volume was approx. 12.5 liters.
• the reaction mixture was mixed transversely to the longitudinal axis by a stirrer (3) with 8 stirrer blades (4) measuring 50 mm x 50 mm, the distance between the stirrer blades and the reactor wall was 25 mm, thus avoiding contact with the reactor wall.
• a stirrer (3) with 8 stirrer blades (4) measuring 50 mm x 50 mm, the distance between the stirrer blades and the reactor wall was 25 mm, thus avoiding contact with the reactor wall.
• 9a) to (9e) for initiator.
• the tubular reactor (1) was continuously supplied with the mixture of substances to be polymerized from an upstream pressure vessel (6) with a volume of 16 liters.
• the upstream pressure vessel (6) was continuously filled with the relevant substances via pumps.
• the product After emerging from the tubular reactor (1), the product was transferred via a pressure-maintaining valve (14) or (15) to a pressureless container (8) with a volume of 1000 liters and collected. At the end of the experiment, the product mixture was aftertreated and bottled.
• composition to be polymerized is a composition to be polymerized:
• This mixture was transferred to the tubular reactor (1) at a rate of 20 kg / h.
• the initiator potassium persulfate was metered in as a 3% strength by weight aqueous solution at the metering points (9a) to (9e).
• the finished product left the tubular reactor (1) with a conversion of approx. 92% and was collected in a pressureless container (8) in vacuo.
• the mixture to be polymerized was introduced at the lower end of the tubular reactor (1) and the product removed at the upper end.
• the valves (10) and (11) were open, the valves (12) and (13) closed.
• the flow rate was approx. 20 liters / h.
• the stirrer speed was 800 revolutions / minute.
• the pressure in the reactor (1) was adjusted to 55 bar via the transfer valve (14).
• the initiator dosing rates were
• the polymerization was ended and the free volume of the reactor (1) was determined by filling it up with water and weighing the amount of water. With this procedure, the reactor volume was determined to be 11.2 liters, that is, in "normal operation" according to the prior art, the reactor loses approx. 1.3 liters volume after 24 hours, equivalent to a corresponding build-up of wall covering.
• the mixture to be polymerized was introduced at the lower end of the reactor (1) and the product was removed at the upper end.
• the valves (10) and (11) were open, the valves (12) and (13) closed.
• the flow rate was approx. 20 liters / h.
• the stirrer speed was 800 revolutions / minute.
• the pressure in the reactor (1) was adjusted to 55 bar via the transfer valve (14).
• the initiator dosing rates were
• Viscosity (Brookfield at 23 ° C and 20 rpm) 1500 mPas

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• 2019
  • 2019-04-30 CN CN201980050622.6A patent/CN112513106A/zh active Pending
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