DE102004049341A1 - New polyurethane rigid foam material comprising an encapsulated latent heat storage, where the heat storage material is e.g. n-hexadecane, n-octadecane, cyclodecane, benzene, dodecyl benzol and lauryl alcohol - Google Patents

Abstract

Polyurethane rigid foam material (A) comprising encapsulated latent heat storage, is new. An independent claim is also included for the preparation of (A).

Description

The The invention relates to rigid polyurethane foams, optionally Can contain isocyanurate, containing encapsulated Latent heat storage (I). Furthermore The invention relates to processes for the production of rigid polyurethane foams by reacting (a) isocyanates with (b) compounds with towards isocyanate groups reactive hydrogen atoms in the presence of (c) propellant and optionally Catalysts (d), (e) additives, particularly preferably foam stabilizers and flame retardants, wherein the reaction in the presence of encapsulated latent heat storage (i) performs.

Polyurethane foams and methods of making these foams are general known and diverse described.

task the invention was to develop rigid polyurethane foams, the improved thermal insulation properties and have an excellent mechanical property profile. The rigid foams should be improved by an improved process accessible be that by improved temperature stability in the Reaction of the isocyanates with the polyols, a total of a temperature drop and shorter Demoulding time distinguishes.

The The task was solved by the rigid polyurethane foams described at the beginning, which may optionally have isocyanurate structures are dissolved.

The Inventive latent heat storage are temperature managers: the ambient temperature increases Heat up, she falls, give them heat from. This is especially for the summer or winter heat protection advantageous because here Energy can be saved. During the phase transformation the temperature remains constant.

One special advantage regarding The rigid foams consist in the delayed rise in temperature during the Foaming. This offers the possibility a faster demolding and thus increase the production capacity.

at the latent heat storage containing capsules (i) are particles with a capsule core and a capsule wall. Subsequently, these particles are called microcapsules designated. The capsule core contains predominantly, preferably more than 95% by weight of latent heat storage materials. The Capsule wall contains in general, polymeric materials. The capsule core is ever solid or liquid after the temperature.

Latent heat storage materials are usually lipophilic substances that have their solid / liquid phase transition in the temperature range of -20 up to 120 ° C, more preferably between 25 and 100 ° C have. In the context of this invention however, become latent heat storage materials preferably used their solid / liquid phase transition in the area just below the human body temperature have or significantly below the temperature development the setting time is .. Preferably, such latent heat storage materials used their solid / liquid Phase transition in the temperature range from 15 to 80 ° C, preferably from 20 to 70 ° C, in particular from 24 to 66 ° C to have.

• – aliphatische Kohlenwasserstoffverbindungen wie gesättigte oder ungesättigte C₁₀-C₅₀-Kohlenwasserstoffe, die verzweigt oder bevorzugt linear sind, z.B. wie n-Hexadecan, n-Octadecan, n-Eicosan, sowie cyclische Kohlenwasserstoffe, z.B. Cyclodecan;
• – aromatische Kohlenwasserstoffverbindungen wie Benzol, Naphthalin, C₁-C₄₀-alkylsubstituierte aromatische Kohlenwasserstoffe wie Dodecylbenzol, Tetradecylbenzol, oder Decylnaphthalin;
• – gesättigte oder ungesättigte C₆-C₃₀-Fettsäuren wie Laurin-, Stearin-, Öl- oder Behensäure, bevorzugt eutektische Gemische aus Decansäure mit z.B. Myristin-, Palmitin- oder Laurinsäure;
• – Fettalkohole wie Lauryl-, Stearyl-, Oleyl-, Myristyl-, Cetylalkohol,
• – C₆-C₃₀-Fettamine, wie Decylamin, Dodecylamin, Tetradecylamin oder Hexadecylamin;
• – Ester wie C₁-C₁₀-Alkylester von Fettsäuren wie Propylpalmitat, Methylstearat oder Methylpalmitat sowie bevorzugt ihre eutektischen Gemische;
• – natürliche und synthetische Wachse wie Montansäurewachse, Montanesterwachse, Carnaubawachs, Polyethylenwachs, oxidierte Wachse, Polyvinyletherwachs, Ethylenvinylacetatwachs oder Hartwachse nach Fischer-Tropsch-Verfahren;
• – halogenierte Kohlenwasserstoffe wie Chlorparaffin, Bromoctadecan, Brompentadecan, Bromnonadecan, Bromeicosan, Bromdocosan.

Suitable substances may be mentioned by way of example:

• Aliphatic hydrocarbon compounds, such as saturated or unsaturated C ₁₀ -C ₅₀ -hydrocarbons, which are branched or preferably linear, for example, such as n-hexadecane, n-octadecane, n-eicosane, and cyclic hydrocarbons, for example cyclodecane;
• Aromatic hydrocarbon compounds such as benzene, naphthalene, C ₁ -C ₄₀ -alkyl-substituted aromatic hydrocarbons such as dodecylbenzene, tetradecylbenzene or decylnaphthalene;
• - saturated or unsaturated C ₆ -C ₃₀ fatty acids such as lauric, stearic, oleic or behenic acid, preferably eutectic mixtures of decanoic acid with, for example, myristic, palmitic or lauric acid;
• Fatty alcohols such as lauryl, stearyl, oleyl, myristyl, cetyl alcohol,
• C ₆ -C ₃₀ fatty amines, such as decylamine, dodecylamine, tetradecylamine or hexadecylamine;
• Esters, such as C ₁ -C ₁₀ -alkyl esters of fatty acids, such as propyl palmitate, methyl stearate or methyl palmitate, and preferably their eutectic mixtures;
• Natural and synthetic waxes such as montanic acid waxes, montan ester waxes, carnauba wax, polyethylene wax, oxidized waxes, polyvinyl ether wax, ethylene vinyl acetate wax or Fischer-Tropsch wax waxes;
• Halogenated hydrocarbons such as chlorinated paraffin, bromoctadecane, bromopentadecane, bromononadecane, bromeicosane, bromodocosan.

Farther Mixtures of these substances are suitable as long as it is not too a melting point depression outside the desired Area comes in, or the heat of fusion of the mixture for a meaningful Application becomes too low.

For example can the above-mentioned halogenated hydrocarbons as a flame retardant admixed become. Furthermore, can also flame retardants such as decabromodiphenyl oxide, octabromodiphenyl oxide, Antimony oxide or flame retardant additives described in US Pat. No. 4,797,160 be added.

Farther it is advantageous to the capsule core forming substances in them soluble Add compounds, so in part to the non-polar substances to prevent occurring freezing point depression. Advantageous As described in US Pat. No. 5,456,852, compounds are used with a 20 to 120 ° C higher Melting point as the actual core substance. Suitable compounds are the fatty acids mentioned above as lipophilic substances, fatty alcohols, fatty amines and aliphatic hydrocarbon compounds, such as. B. n-alkanes.

The Capsule wall usually contains organic polymers. Preferred wall materials, as they are very aging-resistant, are thermosetting polymers. Under duroplastic are wall materials to understand, which do not soften due to the high degree of cross-linking, but decompose at high temperatures. Suitable thermosetting Wall materials are, for example, formaldehyde resins, polyureas and polyurethanes and highly crosslinked methacrylic acid ester polymers.

• – Triazinen wie Melamin
• – Carbamiden wie Harnstoff
• – Phenolen wie Phenol, m-Kresol und Resorcin
• – Amino- und Amidoverbindungen wie Anilin, p-Toluolsulfonamid, Ethylenharnstoff und Guanidin,

oder ihren Mischungen.Formaldehyde resins are understood as meaning reaction products of formaldehyde with

• - Triazines such as melamine
• - Carbamides such as urea
• Phenols such as phenol, m-cresol and resorcinol
• Amino and amido compounds such as aniline, p-toluenesulfonamide, ethyleneurea and guanidine,

or their mixtures.

Preferred formaldehyde resins are urea-formaldehyde resins, urea-resorcin-formaldehyde resins, urea-melamine resins and melamine-formaldehyde resins. Also preferred are the C ₁ -C ₄ alkyl, in particular methyl ether of these formaldehyde resins and the mixtures with these formaldehyde resins. In particular, melamine-formaldehyde resins and / or their methyl ethers are preferred.

Capsule walls made of polyureas and polyurethanes are also possible. The capsule walls are formed by reaction of NH ₂ groups or OH-containing reactants with di- and / or polyisocyanates.

Prefers are microcapsules whose capsule wall is a methacrylic ester polymer, which is preferably crosslinked contains. The degree of crosslinking can for example, with a crosslinker content of 10 wt .-%, based to the total polymer.

The preferred microcapsules are preferably 30 to 95 wt .-% constructed from 30 to 100 wt .-%, of one or more C ₁ -C ₂₄ alkyl esters of acrylic and / or methacrylic acid as monomers I, In addition, the microcapsules of up to 80 wt .-%, preferably from 5 to 60 wt .-%, in particular from 10 to 50 wt .-%, of one or more bi- or polyfunctional monomers as monomers II, which are not soluble in water or are difficult to dissolve and be composed of up to 40 wt .-%, preferably up to 30 wt .-% of other monomers III.

Suitable monomers I are C ₁ -C ₂₄ -alkyl esters of acrylic and / or methacrylic acid. Particularly preferred monomers I are methyl, ethyl, n-propyl and n-butyl acrylate and / or the corresponding methacrylates. Iso-propyl, isobutyl, sec-butyl and tert-butyl acrylate and the corresponding methacrylates are preferred. Further, methacrylonitrile is mentioned. Generally, the methacrylates are preferred.

suitable Monomers II are bi- or polyfunctional monomers which are dissolved in water not soluble or sparingly soluble but have good to limited solubility in the lipophilic Have substance. Under low solubility is a solubility less than 60 g / l at 20 ° C to understand.

Under bi- or polyfunctional monomers are compounds, which have at least 2 non-conjugated ethylenic double bonds.

especially Divinyl and polyvinyl monomers contemplated crosslinking the capsule wall during cause the polymerization.

preferred bifunctional monomers are the diesters of diols with acrylic acid or Methacrylic acid, furthermore the diallyl and divinyl ethers of these diols.

preferred Divinyl monomers are propanediol, butanediol, pentanediol and hexanediol diacrylate or the corresponding methacrylates.

preferred Polyvinyl monomers are trimethylolpropane triacrylate and methacrylate, Pentaerythritol triallyl ether and pentaerythritol tetraacrylate.

When Monomers III, other monomers are contemplated, are preferred Monomers IIIa such as styrene, α-methylstyrene, b-methylstyrene, butadiene, Isoprene, vinyl acetate, vinyl propionate and vinyl pyridine.

Especially preferred are the water-soluble Monomers IIIb, e.g. Acrylonitrile, methacrylamide, acrylic acid, methacrylic acid, itaconic acid, maleic acid, maleic anhydride, N-vinylpyrrolidone, 2-hydroxyethyl acrylate and methacrylate and acrylamido-2-methylpropanesulfonic acid.

The In the context of this invention, microcapsules used by a so-called in situ polymerization can be produced. In this Procedure becomes common from the monomers, a radical initiator, optionally a protective colloid and the lipophilic substance to be encapsulated, a stable oil-in-water emulsion in which they are present as a disperse phase. The proportion of oil phase in the oil-in-water emulsion is preferably at 20 to 60 wt .-%.

Then you can initiate the polymerization of the monomers by heating, the resulting Polymers form the capsule wall, which encloses the lipophilic substance.

In general, the polymerization is carried out at 20 to 100 ° C, preferably at 40 to 80 ° C. The dispersion and polymerization temperature is preferably above the melting temperature of the lipophilic substances. In general, the microcapsules are prepared in the presence of at least one organic protective colloid. A preferred method is, for example, in EP 457 154 described.

It is preferred that the capsules of the latent heat storage are in the form of a particle size distribution, with the proviso that the average particle diameter of the distribution (D _m ) is between 1 and 20 microns and at least 80% of the particles, based on 100% of those present in the distribution Particle (N), have a diameter which has a value between 0.2 D _m and 3 D _m .

The particle size of the microcapsules can be influenced by the production process. Usually, according to the preparation process, the microcapsules are in the form of a particle distribution, provided that no further steps, such as sieving, are carried out. It is preferred that the average particle diameter of the distribution (D _m ) is between 1 and 20 μm, preferably between 2 and 18 μm, more preferably between 3 and 14 μm, and at least 80% of the particles, based on 100% of that in the distribution particles present (N), have a diameter which _m has a value between 0.2 D _m to 3 D, preferably between 0.3 and 2.5 _m D D _m, more preferably between 0.5 and 1.5 _m D D _m has.

The total number of particles (N) present in the distribution is given by the integral of D _min biS D _max :

The average particle diameter Dm (which is also referred to as the mean value of the particle size) is the arithmetic mean value of the particle size weighted by the distribution function. First, multiply each diameter D between D _min (particles having the smallest diameter occurring in the distribution) and D _max (particles having the largest diameter occurring in the distribution) with the number n (d) of the particles having this diameter and form the sum , This is described by

In order to form the mean, then this sum must be divided by the total number of particles (N), ie

• 1 D_min
• 2 D_max
• 3 D_h (= häufigste, in der Verteilung vorkommende Teilchengröße)
• 4 D_z (= Halbwertsdurchmesser, teilt die Fläche in zwei gleich große Teile)
• 5 D_m
• 6 n(D)

Frequently, D _{m is} also referred to as the "center of gravity" of the particle size distribution. To illustrate D _m , D _min , D _max will open 1 directed. In 1 means:

• 1 D _min
• 2 D _max
• 3 D _h (= most common particle size occurring in the distribution)
• 4 D _z (= half-value diameter, divides the area into two equal parts)
• 5 D _m
• 6n (D)

The Determination of particle sizes in the Distribution according to the dynamic light scattering according to ISO13323-1, Edition: 2000-11 (Determination of particle size distribution - Single-particle light interaction methods - Part 1: Light interaction considerations) and ISO / DIS 13323-2, Ausgabe: 2000-09 (Determination of Particle Size Distribution - Particle Measurement by light scattering on single particles - Part 2: Equipment and implementation for light scattering on individual particles).

The Microcapsules can as a powder in the polyols (b) are incorporated. It will be generally from 1 to 40% by weight, preferably from 5 to 15% by weight, especially preferably 7 to 12 wt .-% microcapsules (i), based on the total weight the polyol component (b) containing compound (b), blowing agent (C), catalyst (d) and optionally additive (e) incorporated.

method for the production of rigid polyurethane foams by reaction of (a) isocyanates with (b) isocyanate-reactive compounds, preferably by reacting (a) isocyanates with (b) compounds with opposite Isocyanate-reactive hydrogen atoms preferably in the presence of catalysts (d), (c) blowing agents and optionally (e) additives, particularly preferred is foam stabilizers and flame retardants well known. The inventive method is characterized inventive in that the reaction in the presence of the latent heat storage (i) performs.

To the other components (a) to (e) are as follows accept.

(A) As polyisocyanates are the usual aliphatic, cycloaliphatic and in particular aromatic Di- and / or polyisocyanates in question. Preferably used Toluylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI) and in particular Mixtures of diphenylmethane diisocyanate and Polyphenylenpolymethylenpolyisocyanaten (Crude MDI). The isocyanates can also be modified, for example by incorporation of uretdione, Carbamate, isocyanurate, carbodiimide, allophanate and in particular Urethane groups. For the production of rigid polyurethane foams In particular, crude MDI is used. Preference is also the Use of polymer MDI as isocyanate (a). In the prior art it may be customary Incorporate isocyanurate groups in the polyisocyanate. The isocyanurate formation leads to flame-retardant PIR foams, which are preferred in the technical Hard foam, for example in construction as insulation board or sandwich elements, be used.

(b) As compounds having at least two isocyanate-reactive groups, that is to say having at least two isocyanate-reactive hydrogen atoms, it is generally possible to use compounds which are generally described below. Suitable compounds having at least two isocyanate-reactive groups are, in particular, those which have two or more reactive groups selected from OH groups, SH groups, NH groups, NH ₂ groups and CH-acidic groups, for example β -Diketo groups, carry in molecule. For the preparation of the rigid polyurethane foams preferably produced by the process according to the invention, in particular compounds having 2 to 8 OH groups are used Commitment. Preferably used are polyetherols and / or polyesterols. The hydroxyl number of the polyetherols and / or polyesterols used in the production of rigid polyurethane foams is preferably 100 to 850 mg KOH / g, more preferably 200 to 600 mg KOH / g, the molecular weights are preferably greater than 400 g / mol. Component (b) preferably comprises polyetherpolyols prepared by known processes, for example by anionic polymerization with alkali metal hydroxides, such as sodium or potassium hydroxide or alkali metal alkoxides, such as sodium methylate, sodium or potassium ethylate or potassium isopropoxide as catalysts and with the addition of at least one starter molecule 2 to 8, preferably contains 3 to 8 bonded reactive hydrogen atoms, or be prepared by cationic polymerization with Lewis acids such as antimony pentachloride, boron fluoride etherate, inter alia, or bleaching earth as catalysts of one or more alkylene oxides having 2 to 4 carbon atoms in the alkylene radical. Suitable alkylene oxides are, for example, tetrahydrofuran, 1,3-propylene oxide, 1,2- or 2,3-butylene oxide, styrene oxide and preferably ethylene oxide and 1,2-propylene oxide. The alkylene oxides can be used individually, alternately in succession or as mixtures. Suitable starter molecules are, for example, glycerol, trimethylolpropane, pentaerythritol, sucrose, sorbitol, methylamine, ethylamine, isopropylamine, butylamine, benzylamine, aniline, toluidine, toluenediamine, naphthylamine, ethylenediamine, diethylenetriamine, 4,4'-methylenedianiline, 1,3, - Propanediamine, 1,6-hexanediamine, ethanolamine, diethanolamine, triethanolamine and other dihydric or polyhydric alcohols or mono- or polyhydric amines. Further, component (b) may optionally contain polyesterols, chain extenders and / or crosslinkers. Suitable chain extenders and / or crosslinking agents are, in particular, difunctional or trifunctional amines and alcohols, in particular diols and / or triols having molecular weights of less than 400 g / mol, preferably from 60 to 300. Preference is given to using as compound (b) polyether polyols and / or polyester polyols having a hydroxyl number greater than 160, more preferably greater than 200 mg KOH / g and particularly preferably a functionality of between 2.9 and 8. The compound (b) is generally present in liquid form and preferably contains the encapsulated latent heat storage (i).

When Propellant component (c) are preferably used hydrocarbons. these can in admixture with water and / or other physical blowing agents be used. By this one understands connections, which in the Starting materials of polyurethane production are dissolved or emulsified and evaporate under the conditions of polyurethane formation. It acts for example, hydrocarbons, halogenated hydrocarbons, and other compounds, such as perfluorinated alkanes, such as perfluorohexane, chlorofluorocarbons, as well as ethers, esters, Ketones and / or acetals. The blowing agent component (c) is used preferably in an amount of 2 to 45 wt .-%, preferably 4 to 30 Wt .-%, particularly preferably 5 to 20 wt .-%, based on the total weight of components (b) to (e). It is further preferred that the Propellant component (c) less than 5% by weight, more preferably less than 2% by weight, more preferably less than 1% by weight, in particular 0% by weight, based on the total weight of the components (b) to (e), chlorofluorocarbons, chlorinated hydrocarbons or fluorocarbons. In a preferred embodiment contains the blowing agent mixture (c) thus exclusively hydrocarbons. Especially preferred hydrocarbons are n-pentane, cyclopentane, iso-pentane and / or Mixtures of isomers. In particular, n-pentane and / or cyclopentane used as blowing agent (c), in particular together with water.

When Catalysts (d) can from polyurethane chemistry well known catalysts (d) used become.

The reaction of (a) with (b) is optionally carried out in the presence of (e) additives, such as flame retardants, fillers, cell regulators, foam stabilizers, surface-active compounds and / or stabilizers against oxidative, thermal or microbial degradation or aging, preferably flame retardants and / or or foam stabilizers. Foam stabilizers are substances which promote the formation of a regular cell structure during foaming. For example: silicone-containing foam stabilizers, such as siloxane-oxalkylene copolymers and other organopolysiloxanes. Further alkoxylation of fatty alcohols, oxo alcohols, fatty amines, alkylphenols, dialkylphenols, alkylcresols, alkylresorcinol, naphthol, alkylnaphthol, naphthylamine, aniline, alkylaniline, toluidine, bisphenol A, alkylated bisphenol A, polyvinyl alcohol, and further alkoxylation of condensation products of formaldehyde and alkylphenols, formaldehyde and Dialkylphenols, formaldehyde and alkylcresols, formaldehyde and alkylresorcinol, formaldehyde and aniline, formaldehyde and toluidine, formaldehyde and naphthol, formaldehyde and alkylnaphthol and formaldehyde and bisphenol A. As alkoxylation, for example, ethylene oxide, propylene oxide, poly-THF and higher homologs can be used. As flame retardants, the flame retardants known from the prior art can generally be used. Suitable flame retardants are, for example, brominated ethers (isole), brominated alcohols such as dibromoneopentyl alcohol, tribromoneopentyl alcohol and PHT-4-diol, and also chlorinated phosphates such as tris (2-chloroethyl) phosphate, tris (2-chloroisopropyl) phosphate (TCPP), Tris (1,3-dichloroisopropyl) phosphate, Tris (2,3-dibromopropyl) phosphate and tetrakis (2-chloroethyl) ethylenediphosphate. Besides the abovementioned halogen-substituted phosphates, it is also possible to use inorganic flameproofing agents such as red phosphorus, red phosphorus-containing finishes, aluminum oxide hydrate, antimony trioxide, arsenic oxide, ammonium polyphosphate and calcium sulfate or cyanuric acid derivatives such as melamine or mixtures of at least two flame retardants such as ammonium polyphosphates and melamine and optionally starch used for flameproofing the PU rigid foams produced according to the invention. Diethyl ethane phosphonate (DEEP), triethyl phosphate (TEP), dimethyl propyl phosphonate (DMPP), diphenyl cresyl phosphate (DPK) and others can be used as other liquid halogen-free flame retardants. The flame retardants are in the context of the present invention preferably in an amount of 0 to 65 wt .-%, particularly preferably from 10 to 65 wt .-%, in particular from 15 to 60 wt .-%, particularly preferably between 20 to 50 wt. %, based on the total weight of components (b) to (e) used.

More details about the above and other starting materials are the specialist literature, for example the Kunststoffhandbuch, Volume VII, Polyurethane, Carl Hanser Verlag Munich, Vienna, 1st, 2nd and 3rd editions 1966, 1983 and 1993 can be seen.

to Preparation of the rigid polyurethane foams are the polyisocyanates (a) and components (b) to optionally (e) in such amounts brought to implementation that the isocyanate index of the foam 90 to 350, preferably 100 to 180, particularly preferably 110 to 140 is.

The Polyurethane rigid foams can discontinuously or continuously by known methods (eg double band). The invention described here refers to both methods, but preferably to the continuous one Double belt process.

When It has proved to be particularly advantageous according to the two-component process to work and the latent heat storage according to the invention with the component (b) together with the blowing agents (c), the catalysts (d) and, where appropriate, the additives (e) to a so-called Polyol component (in this document also above as polyol component to combine) and these with the polyisocyanates or Mixtures of the polyisocyanates and optionally blowing agents, also referred to as isocyanate component to bring to implementation. The polyol component without the blowing agent preferably has a viscosity greater than 1000 mPas on.

In a further preferred embodiment, the polyurethane foams have a density, preferably apparent density of less than 100 g / l, particularly preferably less than 60 g / l, in particular less than 50 g / l. Furthermore, the polyurethane foams generally have a compressive strength according to DIN 53 421 of 0.3 N / mm ² or more, more preferably from 0.35 to 0.5 N / mm ² .

The rigid polyurethane foams according to the invention preferably have a closed cell size greater than 90%. The advantages according to the invention, e.g. in terms of Entformeigenschaften, but also arise for open-celled Rigid PU foams, e.g. such for the vacuum technology.

Of the Use of the polyurethane rigid foams according to the invention takes place in particular for thermal insulation, for example of refrigerators, containers or buildings, e.g. in the form of insulated Pipes, boilers, sandwich panels, insulation boards or refrigerators. When Polyurethanes within the meaning of the present patent application are also understood polymeric isocyanate adducts, in addition to urethane groups still contain other groups, such as by reaction the isocyanate group arise with itself, for example isocyanurate groups, or by reaction of the isocyanate groups with other groups as arise with hydroxyl groups, said groups usually together with the urethane groups in the polymer.

Polyol 1:

mit Saccharose und Glycerin gestartet, propoxiliert, Hydroxylzahl 465-515mg/KOH/g; Funktionalität 4,3

Polyol 2:

mit Trimethylolpropan gestartet, propoxiliert, Hydroxylzahl (OHZ) 155-165, Funktionalität 3

The invention will be illustrated by the following examples. Examples

Polyol 1:

started with sucrose and glycerol, propoxylated, hydroxyl number 465-515 mg / KOH / g; Functionality 4.3

Polyol 2:

started with trimethylolpropane, propoxylated, hydroxyl number (OHN) 155-165, functionality 3

information in the table represent parts by weight.

As the stabilizer, Tegostab ^® B8467 the firm Th.Goldschmidt was used; dimethylcyclohexylamine is used as catalyst and cyclopentane as blowing agent. As a microencapsulated latent heat storage (Phase Change Materials, also referred to as PCM in this document) was used Ceracap TM NB 1001 x BASF Aktiengesellschaft. These are microcapsules with a capsule wall of a highly crosslinked methacrylic ester polymer and a paraffin wax with a melting point of 28 ° C as latent heat storage core. The average diameter of the capsules is about 6-10 microns, the particle distribution is narrow, ie there are in the distribution particles with a diameter of about 1 to 20 microns available. As the isocyanate component PMDI was used Lupranat M20S ^® (BASF Aktiengesellschaft) with an NCO content of 31.5. It was foamed at index number 110. The bulk density was 45 +/- 1 g / l, the setting time to 55 +/- 1 sec.

The curing of the rigid foam was quantified by bolt test. The flowability was measured by means of a tube test.

It showed at medium filler contents a minor one Improvement in curing, without affecting the flow properties deteriorated.

The thermal conductivity was using fox device at medium temperature 23 ° C (36 ° C and 10 ° C) measured with NIST standard. The change the thermal conductivity Over time, it was tracked as a measure of how fast a balance is building up the heat flow established. With the heat storage the equilibrium, i. e. the thermal conductivity slower. Of the Foam thus has a high resistance. After 5min shows that the Foam without PCM a thermal conductivity of 21.8mW / mK has a foam with PCM 22 as well as 23.8mW / mK. It must more heat supplied to reach equilibrium.

Based from electron micrograph could be detected that the latent heat storage do not destroy the cell structure. This remains complete received, however, are the latent heat storage predominantly in the Stegen.

The Heat of fusion which is needed for the phase transformation is tracked by DSC. It turned out that below 30 ° C the Phase transformation takes place, they also get in the foam remained and the enthalpy of fusion is greater, the more microcapsules be used.

Maximaltemperatur °C

On the basis of these measurements it became apparent that by using the latent heat storage device, the temperature development can thus be lowered during foaming. When using the microcapsules, the temperature lowers, so that the maximum temperature is lower and the cooling is faster. This results in the same flow properties or mold filling properties, but faster cooling to significantly better demolding or better dimensional stability.

Maximum temperature ° C

Claims (7)

Rigid polyurethane foam containing encapsulated Latent heat storage (I). Polyurethane rigid foam according to claim 1, characterized in that the capsules of the latent heat storage are in the form of a particle size distribution, with the proviso that the average particle diameter of the distribution (D _m ) is between 1 and 20 microns and at least 80% of the particles based on 100% of the particles (N) present in the distribution, have a diameter which has a value between 0.2 D _m and 3 D _m . Process for the production of rigid polyurethane foam by reacting (a) isocyanates with (b) compounds with towards isocyanate groups reactive hydrogen atoms in the presence of (c) propellant and if appropriate, catalysts (d), (e) additives, characterized that is the reaction in the presence of encapsulated latent heat storage (i) performs. Process for the production of rigid polyurethane foam according to claim 3, characterized in that the capsules of the latent heat storage material are in the form of a particle size distribution, with the proviso that the mean particle diameter of the distribution (D _m ) is between 1 and 20 μm and at least 80% of the particles, based on 100% of the particles (N) present in the distribution, have a diameter which has a value between 0.2 D _m and 3 D _m . Process for the production of rigid polyurethane foam according to claim 3, characterized in that as compound (b) polyether polyols and / or polyester polyols having a hydroxyl number greater than 160 mg KOH / g. Process for the production of rigid polyurethane foam according to claim 3, characterized in that as isocyanate (a) polymer MDI starts. Process for the production of rigid polyurethane foam according to claim 3, characterized in that the rigid polyurethane foam a Closed cell size greater than 90% having.