Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
  • B01J13/02—Making microcapsules or microballoons
  • B01J13/06—Making microcapsules or microballoons by phase separation
  • B01J13/14—Polymerisation; cross-linking
  • B01J13/18—In situ polymerisation with all reactants being present in the same phase
  • B01J13/185—In situ polymerisation with all reactants being present in the same phase in an organic phase
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D20/00—Heat storage plants or apparatus in general; Regenerative heat-exchange apparatus not covered by groups F28D17/00 or F28D19/00
  • F28D20/02—Heat storage plants or apparatus in general; Regenerative heat-exchange apparatus not covered by groups F28D17/00 or F28D19/00 using latent heat
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
  • B01J13/02—Making microcapsules or microballoons
  • B01J13/06—Making microcapsules or microballoons by phase separation
  • B01J13/14—Polymerisation; cross-linking
  • B01J13/18—In situ polymerisation with all reactants being present in the same phase
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K5/00—Heat-transfer, heat-exchange or heat-storage materials, e.g. refrigerants; Materials for the production of heat or cold by chemical reactions other than by combustion
  • C09K5/02—Materials undergoing a change of physical state when used
  • C09K5/06—Materials undergoing a change of physical state when used the change of state being from liquid to solid or vice versa
  • C09K5/063—Materials absorbing or liberating heat during crystallisation; Heat storage materials
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D20/00—Heat storage plants or apparatus in general; Regenerative heat-exchange apparatus not covered by groups F28D17/00 or F28D19/00
  • F28D20/02—Heat storage plants or apparatus in general; Regenerative heat-exchange apparatus not covered by groups F28D17/00 or F28D19/00 using latent heat
  • F28D20/023—Heat storage plants or apparatus in general; Regenerative heat-exchange apparatus not covered by groups F28D17/00 or F28D19/00 using latent heat the latent heat storage material being enclosed in granular particles or dispersed in a porous, fibrous or cellular structure
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/14—Thermal energy storage

Definitions

• the present invention relates to microcapsules comprising a paraffin composition as a capsule core and a polymer as a capsule wall composed of C1-C24 alkyl esters of acrylic and / or methacrylic acid, ethylenically unsaturated crosslinkers and optionally other monomers. Moreover, the present invention relates to a process for their preparation and their use in binders, textiles and heat transfer fluids.
• PCM phase change material
• EP-A-1 029 018 and EP-A 1 321 182 teach the use of microcapsules having a capsule wall of highly crosslinked methacrylic acid ester polymer and a latent heat storage core in bonding building materials such as concrete or gypsum.
• DE-A-101 39 171 describes the use of microencapsulated latent heat storage materials in plasterboard.
• the microcapsule walls are constructed by polymerizing methyl methacrylate and butanediol diacrylate in the presence of inorganic solid particles as a protective colloid.
• organic paraffins are used as latent heat storage materials which melt when the phase transition is exceeded. Be such materials
• Microcapsules used in porous building materials such as concrete or gypsum it can be observed for capsules with insufficient tightness over a longer period, a low leakage of paraffins. However, such exhalations are particularly undesirable indoors, so that the present invention is based on denser capsules as a task.
• WO 201 1/004006 teaches that modified microcapsule walls, built up by polymerization of methyl methacrylate and pentaerythritol tri / tetraacrylate, lead to microcapsules with lower emissions in the range of application temperatures.
• microcapsules are low in construction applications, ie have a low evaporation rate and yet have a high heat capacity of> 100, in particular of> 120 kJ / kg microcapsules.
• microcapsules have been found comprising a paraffin composition as a capsule core and a polymer as a capsule wall being built up
• ethylenically unsaturated crosslinkers (monomers II), where at least 80%, based on the ethylenically unsaturated crosslinker, is a crosslinker having three or more ethylenically unsaturated radicals, and
• n-hexadecane 0 to 50 wt .-% n-hexadecane, each based on the paraffin composition comprises.
• the application further relates to a process for their preparation and their use in binders, textiles and heat transfer fluids. It was surprising found that the paraffin composition has an influence on the tightness of the capsules.
• the microcapsules according to the invention comprise the paraffin composition according to the invention as capsule core and a polymer as capsule wall.
• the average particle size of the capsules (D [4,3] by means of light scattering) is 1 to 50 ⁇ .
• the average particle size of the capsules is 1, 5 to 15 ⁇ , preferably 3 to 10 ⁇ .
• preferably 90% of the particles have a particle size of less than twice the average particle size.
• the weight ratio of capsule core to capsule wall is generally from 50:50 to 95: 5.
• Preferred is a core / wall ratio of 70:30 to 93: 7.
• microcapsules of a preferred embodiment of the invention have their solid / liquid phase transition in the temperature range of 25-27 ° C due to their paraffin composition.
• the microcapsules have their solid / liquid phase transition in the temperature range of 22-24 ° C due to their paraffin composition.
• the paraffin composition comprises as essential components n-octadecane, at least one C2o-C24-aliphatic and / or diisopropylnaphthalene and at least one wax with a melting point> 40 ° C and optionally n-hexadecane in the abovementioned proportions.
• n-octane can be used according to the invention in an amount of 35-98, preferably from 70 to 98 and in particular from 75 to 97 wt .-% based on the paraffin composition.
• n-octadecane in> 90% purities, as commercially available. These have a content of n-octadecane based on its total amount of> 92%, preferably> 95%, and for example, under the trade names Parafol ® 18-97 (Sasol Olefins and Surfactants GmbH) or n-octadecane (Chevron Phillips, Roper Thermais) available.
• the Oktadecan in the form of a C-18 paraffin mixture whose n-octadecane content is at least 40 wt .-%. If a paraffin mixture is used, the amount of paraffin mixture is chosen such that the n-octadecane amount contained therein is in the range according to the invention.
• a paraffin mixture is understood as meaning a mixture of alkanes having the general empirical formula C n H 2n + 2. The number n is in the range of 18 and 32. Paraffin blends are obtained from lube cuts of the vacuum distillation of fossil raw materials and further purified or obtained by the Fischer-Tropsch process (Sasol, Shell).
• n-alkanes predominantly unbranched n-alkanes are obtained.
• paraffin mixtures are obtainable, for example, under the name Linpar 18-20 (Sasol), the composition of which contains 45-70% by weight of n-octadecane and 4-12% by weight of eicosane.
• the C2o-C24 aliphatic and / or diisopropylnaphthalene is used according to the invention in an amount of 1-10, preferably from 1 to 5 wt .-% based on the Paraffinzusammen- setting.
• Suitable C2o-C24 aliphatic compounds are n-eicosane, n-tetracosane, and a mixture of C20-C24 aliphatics.
• One example is white oil.
• White oil is a paraffin oil.
• Aliphatic n-eicosane and diisopropylnaphthalene are preferred as C20-C24.
• wax with a melting point> 40 ° C is used according to the invention in an amount of 1-5, preferably from 1 to 3 wt .-% based on the paraffin composition.
• waxes are to be understood as meaning substances which are solid at 20 ° C. and melt above 40 ° C. without decomposition. They are low viscosity in the liquid state. Suitable waxes are
• Hard waxes such as hydrogenated jojoba waxes (see jojoba oil), montan wax and salivary waxes
• Hydrocarbon waxes such as polyalkylene waxes (polyolefin waxes,
• wax with a melting point> 40 ° C prevents the sometimes occurring at the non-polar substances crystallization delay.
• waxes with a melting point> 40 ° C as suitable compounds Sasolwax 6805, British wax 1357, stearic acid and chlorinated paraffins are exemplary.
• Hydrocarbon waxes which include Fischer-Tropsch (FT) waxes (see Fischer-Tropsch paraffins) and the polyolefin waxes, are made from coal, gas and petrochemical raw materials, high, medium, and high molecular weight Low pressure polymerization process forth.
• Fatty acids C16-C22 are the basis for mono-, bis- and polyamide waxes.
• the n-hexadecane is used according to the invention in an amount of 0-50, preferably from 0 to 25 wt .-% based on the paraffin composition.
• the amount of hexadecane added depends on the desired melting temperature of the paraffin composition. According to one embodiment for a paraffin composition with a melting point of 22-24 ° C, the n-hexadecane is 5 to 20 wt .-%. According to another embodiment for a paraffin composition having a melting point of 25-27 ° C, the n-Hexadecananteil 0 to 10 wt .-% based on the paraffin composition.
• the paraffin composition may contain other aliphatic impurities other than C20-C24 aliphatic or a wax with a melting point> 40 ° C, for example aliphatic compounds such as Heptadecane, n-nonadecane, their stereoisomers and the stereoisomers of n-octadecane and n-hexadecane.
• the paraffin composition consists of 35 to 98 wt .-% n-octadecane, 1 to 10 wt .-% of at least one C2o-C24 aliphatic and / or diisopropylnaphthalene, 1 to 5 wt .-% of at least one wax having a melting point> 40 ° C, up to
• n-hexadecane 50% by weight of n-hexadecane and up to 30 preferably up to 7% by weight of one of these various aliphatic compounds.
• a paraffin composition is included
• n-hexadecane 0 to 25 wt .-% n-hexadecane, each based on the paraffin composition.
• the mixture can be prepared from the individual components.
• the eicosan it is also possible, for example, for the eicosan to be metered in admixture with the octadecane since, in the case of a C-18 paraffin mixture, it may already be present in the octadecane.
• the components of the paraffin composition are mixed in advance and used as a mixture. It is advisable to heat the mixture to temperatures of 50 to 100 ° C in order to better mixing in the To achieve melt. It can be stirred in addition. Following a procedure, the octadecane is introduced and the remaining components of the paraffin composition are added.
• the paraffin composition (paraffin composition A) comprises from 70 to 85% by weight of n-octadecane,
• the paraffin composition (paraffin composition B) comprises
• the polymers of the capsule wall generally contain at least 40 wt .-%, preferably at least 45 wt .-% and in a particularly preferred form at least 50 wt .-% and generally at most 90 wt .-%, preferably at most 80 wt. % and in a particularly preferred form at most 75% by weight of C1-C24
• the polymers of the capsule wall generally contain at least 10 wt .-%, preferably at least 15 wt .-%, preferably at least 20 wt .-% and generally at most 60 wt .-%, preferably at most 55 wt .-% and in particular preferably at least 50 wt .-% of one or more ethylenically unsaturated crosslinkers (monomers II) copolymerized, based on the total weight of the monomers, wherein at least 80 wt.%, Preferably at least 95 wt .-%, in particular 100% based on the ethylenically unsaturated Crosslinker is a crosslinker having three or more ethylenically unsaturated radicals.
• the polymers of the capsule wall contain as monomers II only crosslinkers with three or more ethylenically unsaturated radicals in copolymerized form.
• the polymers may contain up to 30% by weight, preferably up to 20% by weight, in particular up to 10% by weight, particularly preferably 0 to 5% by weight, of one or more monoethylenically unsaturated monomers (monomer III) from the monomo- I are different, in copolymerized form, based on the total weight of the monomers.
• microcapsules according to the invention whose capsule wall is built up
• the capsule wall is composed only of monomers of groups I and II.
• Suitable monomers I are C 1 -C 24 -alkyl esters of acrylic and / or methacrylic acid. Preference is given to isopropyl, isobutyl, sec-butyl and tert-butyl acrylate and isopropyl, isobutyl, sec-butyl and tert-butyl methacrylate. Particularly preferred monomers I are methyl, ethyl, n-propyl and n-butyl acrylate and the corresponding methacrylates. Generally, the methacrylates are preferred.
• Crosslinkers having three or more ethylenically unsaturated radicals are, for example, the polyesters of polyols with acrylic acid and / or methacrylic acid, and also the polyallyl and polyvinyl ethers of these polyols.
• pentaerythritol tetraacrylate is generally present in industrial blends mixed with pentaerythritol triacrylate and minor amounts of oligomerization products.
• the ethylenically unsaturated crosslinker may be crosslinkers having two ethylenically unsaturated radicals.
• Crosslinkers with vinyl, allyl, acrylic or methacrylic groups are preferably used.
• Suitable crosslinkers having two ethylenically unsaturated radicals are, for example, divinylbenzene and divinylcyclohexane and preferably the diesters of diols with acrylic acid or methacrylic acid, furthermore the diallyl and divinyl ethers of these diols.
• Examples which may be mentioned are ethanediol diacrylate, ethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, diethylene glycol diacrylate, dipropylene glycol diacrylate, methallyl methacrylamide, allyl acrylate and allyl methacrylate.
• Particularly preferred are propanediol, butanediol, pentanediol and hexanediol diacrylate and the corresponding methacrylates.
• monomers III are simply ethylenically unsaturated monomers (monomer III), which are different from the monomers I, into consideration.
• Suitable monomers III are monounsaturated monomers such as vinyl acetate, vinyl propionate, vinylpyridine and styrene or ⁇ -methylstyrene, acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, vinylphosphonic acid, maleic anhydride, 2-hydroxyethyl acrylate and methacrylate, acrylamido-2-methylpropanesulfonic acid, Methacrylonitrile, acrylonitrile, methacrylamide, N-vinylpyrrolidone, N-methylolacrylamide, N-methylolmethacrylamide, dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate.
• microcapsules according to the invention can be prepared by a so-called in situ polymerization.
• the principle of microcapsule formation is based on the fact that the monomers, free radical initiator, protective colloid and the lipophilic substance to be encapsulated are used to prepare an oil-in-water emulsion in which the monomers and the paraffin composition are in the form of a disperse phase. According to one embodiment, it is possible to add the radical initiator only after the dispersion.
• the polymerization of the monomers is initiated by heating and optionally controlled by further increase in temperature, wherein the resulting polymers form the capsule wall, which encloses the paraffin composition.
• This general principle is described, for example, in DE-A-10 139 171, to the contents of which reference is expressly made.
• the microcapsules are prepared in the presence of at least one organic and / or inorganic protective colloid.
• organic and inorganic protective colloids may be ionic or neutral.
• Protective colloids can be used both individually and in mixtures of several identically or differently charged protective colloids.
• the microcapsules are preferably prepared in the presence of an inorganic protective colloid, in particular in combination with an organic protective colloid.
• Organic protective colloids are preferably water-soluble polymers which reduce the surface tension of the water from 73 mN / m to a maximum of 45 to 70 mN / m and thus ensure the formation of closed capsule walls and microcapsules with preferred particle sizes in the range of 0.5 to 50 ⁇ , preferably 0 , 5 to 30 ⁇ particular 0.5 to 10 ⁇ form.
• Organic anionic protective colloids are sodium alginate, polymethacrylic acid and their copolymers, the copolymers of sulfoethyl acrylate and methacrylate, Sulfopropyl acrylate and methacrylate, N- (sulfoethyl) -maleimide, 2-acrylamido-2-alkylsulfonic acids, styrenesulfonic acid and vinylsulfonic acid.
• Preferred organic anionic protective colloids are naphthalenesulfonic acid and naphthalenesulfonic acid-formaldehyde condensates and above all polyacrylic acids and phenolsulfonic acid-formaldehyde condensates.
• Organic neutral protective colloids are, for example, cellulose derivatives such as hydroxyethylcellulose, methylhydroxyethylcellulose, methylcellulose and carboxymethylcellulose, polyvinylpyrrolidone, copolymers of vinylpyrrolidone, gelatin, gum arabic, xanthan, casein, polyethylene glycols, polyvinyl alcohol and partially hydrolyzed polyvinyl acetates and also methylhydroxypropylcellulose.
• Preferred organic neutral protective colloids are polyvinyl alcohol and partially hydrolyzed polyvinyl acetates and methylhydroxy (C 1 -C 4) alkyl cellulose.
• a combination of a protective colloid based on SiC> 2 and a methylhydroxy (C 1 -C 4) -alkylcellulose is preferably used. It has been shown that the combination with a low molecular weight methylhydroxy (Ci-C4) -alkylcellulose leads to advantageous properties.
• Methylhydroxy- (C 1 -C 4) -alkylcellulose is to be understood as meaning methylhydroxy- (C 1 -C 4) -alkylcellulose of very different degrees of methylation, as well as degrees of alkoxylation.
• Methylhydroxy- (C 1 -C 4) -alkylcelluloses are prepared in known manner by two reaction steps.
• the alkoxylation of cellulose with alkylene oxides takes place in one step.
• the second step the methylation of existing hydroxyl groups takes place with a methyl halide.
• These two reactions usually take place in succession, but can also be carried out simultaneously.
• the degree of substitution of the cellulose varies.
• the average degree of substitution (DS) indicates how many hydroxyl units have been etherified on a dehydroglucose unit on average and can be from 0 to 3.
• the molar degree of substitution (MS) indicates the average number of alkoxy units per dehydroglycose unit, and can also be greater than 3 by the construction of side chains during the alkoxylation.
• the preferred methylhydroxy (C 1 -C 4) -alkylcelluloses have an average degree of substitution DS of 1.1 to 2.5 and a molar degree of substitution MS of 0.03 to 0.9.
• Suitable methylhydroxy (C 1 -C 4) -alkylcellulose are, for example, methylhydroxyethylcellulose or methylhydroxypropylcellulose. Particularly preferred is methyl hydroxypropyl cellulose.
• Such methylhydroxy- (Ci-C4) are -alkylcelluloses examples game as available under the tradename Culminal ® of the company Hercules / Aqualon.
• the micro capsules are prepared by preparing an oil-in-water emulsion comprising, as essential components, the monomers, free radical initiator, inorganic protective colloid and the lipophilic substance to be encapsulated, and initiating the polymerization.
• the polymerization is controlled by increasing the temperature, the resulting polymers forming the capsule wall enclosing the paraffin composition.
• the inorganic protective colloid is preferably inorganic solid particles, so-called Pickering systems.
• a Pickering system can consist of the solid particles alone or additionally of auxiliaries which improve the dispersibility of the particles in water or the wettability of the particles by the lipophilic phase.
• auxiliaries which improve the dispersibility of the particles in water or the wettability of the particles by the lipophilic phase.
• the mode of action and its use is described in EP-A-1 029 018 and EP-A-1 321 182, to the contents of which reference is expressly made.
• the inorganic solid particles may be metal salts, such as salts, oxides and hydroxides of calcium, magnesium, iron, zinc, nickel, titanium, aluminum, silicon, barium and manganese. Mention may be made of magnesium hydroxide, magnesium carbonate, magnesium oxide, calcium oxalate, calcium carbonate, barium carbonate, barium sulfate, titanium dioxide, aluminum oxide, aluminum hydroxide and zinc sulfide. Silicates, bentonite, hydroxyapatite and hydrotalcites are also mentioned. Particular preference is given to SiO 2 -based silicas, magnesium pyrophosphate and tricalcium phosphate. Suitable SiO 2 -based protective colloids are finely divided silicas.
• colloidal dispersions of silica can be dispersed as fine, solid particles in water. But it is also possible to use so-called colloidal dispersions of silica in water. Such colloidal dispersions are alkaline, aqueous mixtures of silica. In the alkaline pH range, the particles are swollen and stable in water. For use of these dispersions as protective colloid, it is advantageous if the pH of the oil-in-water emulsion is adjusted to pH 2 to 7 with an acid. Preferred colloidal dispersions of silica at pH 9.3 have a specific surface area in the range of 70 to 90 m 2 / g.
• SiO 2 -based protective colloids preference is given to highly disperse silicas whose mean particle sizes in the range from 40 to 150 nm at pH values in the case of range from 8 - 1 1.
• Examples include Levasil® ® 50/50 (HC Starck), Köstrosol ® 3550 (CWK Bad Köstritz), and Bindzil ® mentioned 50/80 (Akzo Nobel Chemicals).
• a combination of an S1O2-based protective colloid and a methylhydroxy (Ci-C4) -alkylcellulose is used. It has been shown that the combination with a low molecular weight methylhydroxy (Ci-C4) -alkylcellulose leads to advantageous properties.
• a methylhydroxy (C 1 -C 4) -alkylcellulose having an average molecular weight (weight average) ⁇ 50,000 g / mol, preferably from the range from 5,000 to 50,000 g / mol, preferably from 10,000 to 35,000 g / mol , in particular 20 000 to 30 000 g / mol used.
• the protective colloids are used in amounts of 0.1 to 25 wt .-%, preferably 0.1 to 20, preferably from 0.5 to 15 wt .-%, based on the sum of paraffin composition and monomers.
• inorganic protective colloids preference is given to amounts of 0.5 to 20, preferably 0.5 to 18,% by weight, based on the sum of the paraffin composition and monomers.
• Organic protective colloids are preferably used in amounts of from 0.1 to 10% by weight, based on the microcapsule (core and wall). Those according to a preferred embodiment in combination with an SiO 2 -based
• Protective colloid used methylhydroxy (Ci-C4) -alkylcellulose is thereby preferably in an amount of 0.01 wt .-% to 1, 0 wt .-%, in particular from 0.05 wt .-% to 0.1 wt. % based on sum of paraffin composition and monomers used.
• Radical initiators for the free-radical polymerization reaction which can be used are the customary oil-soluble peroxo and azo compounds, advantageously in amounts of from 0.2 to 5% by weight, based on the weight of the monomers.
• Oil-soluble means that the radical starter is part of the oil phase of the oil-in-water emulsion and initiates the polymerization there.
• it can be fed as such, but preferably as a solution, emulsion or suspension, as a result of which, in particular, small amounts of radical initiator can be metered more precisely.
• Preferred free-radical initiators are tert-butyl peroxone-decanoate, tert-butyl
• free-radical initiators are di (3,5,5-trimethylhexanoyl) peroxide, 4,4'-azobisisobutyronitrile, tert-butyl perpivalate, dilauroyl peroxide, tert-butyl
• Butyl peroxoneodecanoate and dimethyl 2,2-azobisisobutyrate have a half-life of 10 hours in a temperature range of 30 to 100 ° C.
• the polymerization is carried out at 20 to 100 ° C, preferably at 40 to 95 ° C.
• the oil-in-water emulsion is to be formed at a temperature at which the core material is liquid / oily. Accordingly, a radical initiator must be selected whose decomposition temperature is above this temperature and the polymerization is also carried out 2 to 50 ° C above this temperature, so that optionally selects radical initiator whose decomposition temperature is above the melting point of the paraffin composition.
• a common process variant for paraffin compositions with a melting point up to about 60 ° C is a reaction temperature starting at 45 ° C, which is increased in the course of the reaction to 85 ° C.
• Advantageous free radical initiators have a 10-hour half life in the range of 45 to 65 ° C, such as t-butyl perpivalate.
• the polymerization is carried out at atmospheric pressure, but it is also possible at reduced or slightly elevated pressure z.
• the reaction times of the polymerization are normally 1 to 10 hours, usually 2 to 5 hours.
• aqueous microcapsule dispersions largely free of odor carriers, such as residual monomers and other volatile organic constituents.
• This can be achieved physically in a manner known per se by distillative removal (in particular via steam distillation) or by stripping with an inert gas.
• distillative removal in particular via steam distillation
• stripping with an inert gas.
• it can be done chemically, as described in WO 99/24525, advantageously by redox-initiated polymerization, as described in DE-A 44 35 423, DE-A 44 19 518 and DE-A 44 35 422.
• the re-addition of a radical initiator is required, which defines the onset of postpolymerization.
• post-polymerization with salts of the peroxodisulfonic acid as radical initiator is initiated.
• Suitable salts are, in particular, ammonium, sodium and potassium peroxodisulfuric acid.
• the alkali metal salts of peroxydisulphuric acid are water-soluble and start the postpolymerization in and out of the water phase.
• the salts of peroxodisulfuric acid are expediently used in amounts of from 0.2 to 5% by weight, based on the weight of the monomers. It is possible to dose them at once or over a certain period of time.
• the temperature for the post-polymerization is usually 60 to 100 ° C.
• the duration of the postpolymerization is usually 0.5 to 5 hours.
• the result is particularly low-odor microcapsules.
• the post-polymerization can be carried out by adding reducing agents such as sodium bisulfite even at lower temperatures.
• reducing agents such as sodium bisulfite even at lower temperatures.
• the addition of reducing agents can further reduce the residual monomer content.
• microcapsules having an average particle size in the range from 0.5 to 100 ⁇ m it being possible to adjust the particle size in a manner known per se by means of the shearing force, the stirring speed and its concentration.
• the microcapsules according to the invention can be processed directly as an aqueous microcapsule dispersion or in the form of a powder.
• the microcapsules according to the invention can optionally subsequently be isolated by spray drying.
• the spray drying of the microcapsule dispersion can be carried out in the usual way.
• the procedure is that the inlet temperature of the hot air flow in the range of 100 to 200 ° C, preferably 120 to 160 ° C, and the output temperature of the hot air flow in the range of 30 to 90 ° C, preferably 60 to 80 ° C.
• the spraying of the aqueous polymer dispersion in the stream of hot air can take place, for example, by means of single-fluid or multi-fluid nozzles or via a rotating disk.
• the deposition of the polymer powder is usually carried out using cyclones or filter separators.
• the sprayed aqueous polymer dispersion and the stream of hot air are preferably conducted in parallel.
• spray-auxiliaries are added to the spray-drying to facilitate spray-drying or to set certain powder properties, e.g.
• Advantageous spray aids are, for example, water-soluble polymers of the polyvinyl alcohol or partially hydrolyzed polyvinyl acetates, cellulose derivatives such as Hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, methylhydroxyethylcellulose and methylhydroxypropylcellulose, starch, polyvinylpyrrolidone, copolymers of vinylpyrrolidone, gelatin, preferably polyvinyl alcohol and partially hydrolyzed polyvinyl acetates and methylhydroxypropylcellulose.
• cellulose derivatives such as Hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, methylhydroxyethylcellulose and methylhydroxypropylcellulose
• starch polyvinylpyrrolidone, copolymers of vinylpyrrolidone
• gelatin preferably polyvinyl alcohol and partially hydrolyzed polyvinyl acetates and methylhydroxypropylcellulose.
• latent heat storage materials are substances which have a phase transition in the temperature range in which heat transfer is to be carried out.
• the microcapsules according to the invention have their solid / liquid phase transition in the temperature range of 22-24 ° C. or 25-27 ° C.
• the microcapsules of the invention have a high
• a broad field of application for the microcapsules according to the invention is their use as latent heat storage material in binders with mineral, silicate or polymeric binders.
• microcapsules according to the invention are suitable for the modification of mineral binders (mortar-like preparations) containing a mineral binder consisting of 70 to 100 wt .-% cement and 0 to 30 wt .-% gypsum. This is especially true when cement is the sole mineral binder.
• mineral binders mortar-like preparations
• DE-A 196 23 413 Reference is made to WO 201 1/004006 and DE-A 196 23 413.
• the dry compositions of mineral binders contain, based on the amount of mineral binder, 0.1 to 50 wt .-%, preferably 5 to 40 wt .-%, particularly preferably 10 to 30 wt .-% microcapsules.
• the microcapsules of the invention are preferably used as an additive in mineral coating materials such as plaster.
• a plaster for the interior is usually composed of gypsum as a binder.
• the weight ratio of gypsum / microcapsules is from 95: 5 to 70: 30. Higher microcapsule proportions are, of course, possible.
• Exterior coatings such as exterior facades or damp rooms may contain cement (cementitious plasters), lime or waterglass (mineral or silicate plasters) or plastic dispersions (synthetic resin plasters) as binders together with fillers and optionally coloring pigments.
• cement cementitious plasters
• lime or waterglass mineral or silicate plasters
• plastic dispersions synthetic resin plasters
• the proportion of microcapsules in the total solids corresponds to the weight ratios for gypsum plasters.
• microcapsules of the invention are suitable as an additive in polymeric moldings or polymeric coating compositions. These are thermoplastic and thermosetting plastics to understand in their processing, the microcapsules are not destroyed. Examples are epoxy, urea, melamine, polyurethane and silicone resins and also paints both solvent-based, high-solids-based, powder coating or water-based paint and dispersion films.
• the microcapsule powder is also suitable for incorporation in plastic foams and fibers. Examples of foams are polyurethane foam, polystyrene foam, latex foam and melamine resin foam.
• microcapsules according to the invention are suitable as additives in lignocellulose-containing moldings, such as chipboard, MDF and HDF boards, cork boards or OSB boards as described in WO2005 / 1 16559, to which reference is expressly made.
• microcapsules according to the invention are processed in mineral moldings which are foamed.
• a particularly preferred embodiment for the incorporation of the microcapsules in mineral binders is the modification of gypsum plasterboards or magnesia panels as described in PCT / EP2010 / 059888 (WO 201 1/004006), to which reference is expressly made.
• the microcapsules according to the invention are advantageously suitable as latent heat storage for the modification of fibers and textile products as described in WO 201 1/004006 to the disclosure of which reference is expressly made.
• the microcapsules according to the invention are suitable as latent heat storage for the production of heat transfer fluid.
• the term heat transfer fluid in the context of this application both liquids for the transport of heat as well as liquids for the transport of cold, ie cooling liquids meant. The principle of heat energy transfer is the same in both cases and differs only in the direction of transfer.
• the particle size of the microcapsule dispersion was determined with a Malvern Particle Sizer Type 3600E and a Malvern Mastersizer 2000, respectively, according to a standard measurement method documented in the literature.
• the D [v, 0,1] value indicates that 10% of the particles have a particle size (by volume) up to this value.
• D [v, 0.5] means that 50% of the particles and D [v, 0.9] means that 90% of the particles have a particle size (by volume) less than or equal to this value.
• the span value results from the quotient of the difference D [v, 0,9] - D [v, 0,1] and D [v, 0,5].
• the D [4,3] value is the weight average.
• VOC volatile organic compounds
• gypsum plasterboard The emission of VOC (volatile organic compounds) from gypsum plasterboard is determined after defined storage by means of a FLEC measurement and by a GC / MS system qualitatively and quantitatively, in accordance with DIN ISO 16000-6, DIN ISO16000-10 and DIN ISO 16017- 1 determined.
• the gypsum board is first conditioned in a metal frame (internal dimensions: 10.5 x 14.0 x 1.5 cm) incl. Base plate for 24 hours at 30 ° C in a drying oven (Heraeus T 5042 EK).
• the exhaust air is passed through an adsorption tube filled with Tenax TA.
• the VOCs emitted from the plate are then thermally desorbed from the Tenax tube (thermal desorber: Turbomatrix ATD from Perkin Elmer with GC 6890 and MS 5973 from Agilent or Thermodesorber TD20 with GC / MS-QP 2010 S from Shimadzu) and at the gas chromatograph, as known to those skilled in the art analyzed.
• Linpar 18-20 C-18 paraffin mixture containing n-octadecane and eicosan
• aqueous phase was initially introduced at 40 ° C., into which the molten and homogeneously mixed oil phase was added and dispersed for 40 minutes with a high-speed dissolver stirrer (disk diameter 5 cm) at 3500 rpm.
• Addition 1 was added.
• the emulsion was heated to 67 ° C. with stirring with an anchor raker in the course of 60 minutes and to 90 ° C. within a further 60 minutes.
• Feed 1 was metered into the resulting microcapsule dispersion with stirring at 90 ° C. for 90 minutes and then stirred for 60 minutes at this temperature. It was then cooled to room temperature and neutralized with aqueous sodium hydroxide solution.
• Example 1 a microcapsules was prepared by only the eicosan was replaced by the same amount of Baysilone oil (Example 1 b - not according to the invention) or white oil (Example 1 c).
• the proportion of inorganic protective colloid is in all examples 15 wt .-% based on the solid.
• the solids content of the microcapsule dispersion, the microcapsule size, the evaporation rate (ADR), as well as the heat capacity and the emission in a gypsum board are shown in Table 1. Table 1: Properties of the microcapsules
• Microcapsules were prepared analogously to Example 2a by replacing only the diisopropyl naphthalene with the same amount of white oil (Example 2b) or naphthalene (Example 2c - not according to the invention).
• the proportion of the inorganic protective colloid in all examples is 17.5% by weight, based on the amount of monomers and paraffin composition used.
• the solids content of the microcapsule dispersion, the microcapsule size, the evaporation rate (ADR), and the heat capacity and the emission in a gypsum board are shown in Table 2. Table 2: Properties of the microcapsules
• a microcapsule dispersion with an average particle size D [4,3] of 4.0 ⁇ m and a solids content of 43% was obtained.
• the evaporation rate (2 h 105 ° C, 1 h 180 ° C) was 41, 1%.
• the SVOC values measured in the FLEC amounted to 60 ⁇ g / m 3 . Examples 4b-4g
• Microcapsules were prepared analogously to Example 4a by replacing only the eicosan.
• the proportion of inorganic protective colloid in all examples is 15% by weight, based on the amount of monomers used and paraffin composition.
• the solids content of the microcapsule dispersion, the microcapsule size, the evaporation rate (ADR), and the heat capacity and the emission in a gypsum board are shown in Table 3.
• Luwax LG montan wax ester, octacosanoic acid transesterified with natural alcohols
• the examples show that polymeric waxes instead of C20-24 aliphatic compounds give poor results.
• a microcapsule dispersion with an average particle size D [4.3] of 3.9 ⁇ m and a solids content of 44.6% was obtained.
• the evaporation rate (2 h at 105 ° C, 1 h at 180 ° C) was 36.6%.
• the SVOC values measured in the FLEC amounted to 1 18 ⁇ g / m 3 .

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• 2012
  • 2012-02-13 JP JP2013553889A patent/JP6005067B2/ja not_active Expired - Fee Related
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