EP4259684A1

EP4259684A1 - Production of polyurethane foam

Info

Publication number: EP4259684A1
Application number: EP21810379.4A
Authority: EP
Inventors: Michael SUCHAN; Michael Ferenz; Carsten Schiller
Original assignee: Evonik Operations GmbH
Current assignee: Evonik Operations GmbH
Priority date: 2020-12-08
Filing date: 2021-11-22
Publication date: 2023-10-18
Also published as: JP2023553096A; KR20230117741A; CA3201374A1; CN116568721A; WO2022122360A1; US20240043646A1

Abstract

A composition for producing polyurethane foam, in particular rigid polyurethane foam, comprising at least one isocyanate component, a polyol component, optionally a catalyst that catalyzes the formation of a urethane or isocyanurate bond, and a blowing agent, the composition comprising polyester polysiloxane block copolymers.

Description

Production of polyurethane foam

The present invention is in the field of polyurethanes, particularly polyurethane foams. In particular, it relates to the production of polyurethane foams using polyester-polysiloxane block copolymers and also to the use of these foams. These are in particular rigid polyurethane foams.

In the context of the present invention, polyurethane (PU) is understood to mean in particular a product obtainable by reaction of polyisocyanates and polyols or compounds having isocyanate-reactive groups. In addition to the polyurethane, other functional groups can also be formed, such as uretdiones, carbodiimides, isocyanurates, allophanates, biurets, ureas and/or uretimines. For the purposes of the present invention, PU is therefore understood to mean both polyurethane and polyisocyanurate, polyureas and polyisocyanate reaction products containing uretdione, carbodiimide, allophanate, biuret and uretimine groups. In the context of the present invention, polyurethane foam (PU foam) is understood to mean foam which is obtained as a reaction product based on polyisocyanates and polyols or compounds with isocyanate-reactive groups. In addition to the polyurethane that gives the product its name, other functional groups can also be formed, such as allophanates, biurets, ureas, carbodiimides, uretdiones, isocyanurates or uretimines.

In connection with the provision of PU foams, in particular PU rigid foams, it is a fundamental concern to produce such PU foams which have good flame retardant properties. For this reason, corresponding flame retardants which have flame-retardant properties are described in the known prior art. Against this background, there is still a great need for agents which enable good flame retardant properties to be produced when PU foams are made available.

Against this background, the specific object of the present invention was to make it possible to provide PU foams, in particular rigid PU foams, with good flame retardant properties.

This object is solved by the subject matter of the invention. The subject of the invention is a composition for producing PU foam, in particular PU rigid foam, comprising at least one isocyanate component, a polyol component, blowing agent, optionally a catalyst which catalyzes the formation of a urethane or isocyanurate bond, the composition includes polyester-polysiloxane block copolymers.

The subject of the invention is associated with a variety of advantages. It enables the provision of PU foams, in particular rigid PU foams, with good flame retardant properties. This is advantageously made possible without impairing the other properties of the foam, in particular its mechanical properties. Especially with a view to the provision of PU rigid foams, particularly fine-celled, uniform and low-defect foam structures are also made possible. This makes it possible to provide corresponding PU foams with particularly good performance properties, and in particular the thermal insulation capacity of rigid PU foams is positively influenced. The invention makes it possible in particular to improve the flame retardant properties of corresponding PU foams in such a way that the amount of conventional flame retardants used in the production of corresponding PU foams can be reduced. The polyester-polysiloxane block copolymers of this invention also act as foam stabilizers.

Polyester-polysiloxane block copolymers and their preparation have long been known to those skilled in the art. They can be prepared, for example, by reacting organofunctional siloxanes with cyclic esters with the addition of catalysts, e.g. by reacting hydroxy-alkylsiloxanes with s-caprolactone in the opposite direction of an organotin compound as a catalyst. In the experimental part, the synthesis of block copolymers that can be used according to the invention is described by means of 4 examples.

According to a particularly preferred embodiment of the invention, polyester-polysiloxane block copolymers of the Formzji oroie-- l 1 used, or

^R1R1R1 ^_ ^_

-Si-O- -Si-0 — Si-R ²

^R3 ^R4 R1 ^abc

Formula 1 in it

R ¹ = identical or different aliphatic or aromatic hydrocarbon radicals having 1 to 16 carbon atoms, preferably aliphatic or aromatic hydrocarbon radicals having 1 to 8 carbon atoms, in particular methyl or phenyl,

R ² = identical or different radicals from the group R ¹ , R ³ or R ⁴ , preferably R ¹ ,

R ³ = identical or different polyester radicals, preferably polyester radicals of the formula 2,

R ⁵ = identical or different divalent alkyl radicals which are optionally interrupted by one or more oxygen atoms, preferably -(CH2)3-, -(CH2)B-, -(CH2)3OCH2CH2- or -(CH2)3OCH2CH(CH3)-

R ^e = O or NH or NMe, preferably O, R ⁷ = identical or different divalent alkyl radicals having 1 to 20 carbon atoms, preferably alkyl radicals of the general formula -[CR ⁹ 2]e-,

R ⁹ = identical or different alkyl radicals having 1 to 8 carbon atoms or H, preferably methyl or H,

R ⁸ = identical or different radicals of the general formula -C(O)R ¹⁰ or H, preferably H,

R ¹⁰ = identical or different alkyl radicals having 1 to 16 carbon atoms, preferably methyl,

R ⁴ = identical or different polyether radicals, preferably identical or different polyether radicals of the formula 3

formula 3

R ¹¹ = identical or different divalent alkyl radicals having 2 to 12 carbon atoms, preferably divalent alkyl radicals having 3 to 6 carbon atoms, in particular -(CFhh-,

R ¹² = identical or different alkyl radicals having 1 to 12 carbon atoms, preferably methyl, ethyl or phenyl,

R ¹³ = identical or different radicals from the group: -C(O)R ¹⁰ , H and alkyl radicals with 1-8 carbon atoms, preferably -C(O)CH3, H or methyl, a=5-200, preferably 5-100 , particularly preferably 10 - 80, b = 1 - 20, preferably 1 - 15, particularly preferably 2 - 10, c = 0 - 20, preferably 0 - 15, particularly preferably 0, d = 2 to 80, preferably 2 to 60, particularly preferably 3 to 40 e=1-16, preferably 1 to 12, particularly preferably 1 to 6 x=0 to 80, preferably 0 to 60, particularly preferably 3 to 40 y=0 to 80, preferably 0 to 60, particularly preferably 3 to 40 z=0 to 60, preferably 0 to 20, particularly preferably 0, with the proviso that x+y+z>2, and with the proviso that at least one radical R ³ must be present in the molecule, and preferred at least two different radicals R ⁷ are present in the molecule.

Corresponding compositions show particularly advantageous results with regard to the advantages according to the invention described above, such as in particular flame retardancy and foam stabilization.

It corresponds to a further particularly preferred embodiment of the invention if the polyester-polysiloxane block copolymers according to the invention are produced by reacting cyclic esters, their cyclic dimers or higher analogues with alcohol and/or amino functional siloxanes, preferably derived from formulas 1 and 2, are obtained.

Furthermore, it is preferred that at least two or more different cyclic esters, in particular selected from propiolactone, lactide, caprolactone, butyrolactone or valerolactone, are used to produce the polyester-polysiloxane block copolymers according to the invention. This corresponds to a further particularly preferred embodiment of the invention.

If the polyester-polysiloxane block copolymers are used in a total amount of 0.01 to 15 parts, preferably 0.1 to 10 parts, particularly preferably 0.1 to 5 parts, based on 100 parts of polyols, this corresponds to a further particularly preferred one embodiment of the invention.

Furthermore, it was surprisingly found that the combined use of polyester-polysiloxane block copolymers according to the invention with certain blowing agents gives particularly advantageous results with regard to the advantages according to the invention mentioned above, such as in particular flame retardancy and foam stabilization.

And so it corresponds to a particularly preferred embodiment if the composition according to the invention contains water, hydrocarbons having 3, 4 or 5 carbon atoms, preferably cyclo-, iso- and/or n-pentane, fluorocarbons, preferably HFC 245fa, HFC 134a and /or HFC 365mfc, chlorofluorocarbons, preferably HCFC 141 b, hydrofluoroolefins (HFO) or hydrohaloolefins such as 1234ze, 1234yf, 1224yd, 1233zd(E) and/or 1336mzz, oxygen-containing compounds such as methyl formate, acetone and/or dimethoxymethane, or chlorinated hydrocarbons , preferably dichloromethane and/or 1,2-dichloroethane, water, cyclopentane, isopentane and/or n-pentane, 1233zd(E) or 1236mzz being used in particular.

Furthermore, it may be possible for polyester-polysiloxane block copolymers according to the invention to also contain polyether side chains in addition to the polyester side chains. This corresponds to a further preferred embodiment of the present invention.

The polyester-polysiloxane block copolymers according to the invention not only improve the flame retardant properties of the PU foam, but also act as a foam stabilizer. It even allows the complete substitution of conventional foam stabilizers, which are usually polyether siloxanes, which in turn do not contain any polyester side chains. Thus, a composition according to the invention in which exclusively polyether-containing siloxane-based foam stabilizers (= silicone polyether copolymers which do not contain any polyester side chains), based on the total amount of foam stabilizers, corresponds to less than 15% by weight, preferably less than 10% by weight, in particular less than 5% by weight or none at all, a preferred embodiment of the invention. Nevertheless can mixtures with other foam stabilizers can also be used, in particular with polyether-containing siloxane-based foam stabilizers.

Furthermore, it corresponds to a preferred embodiment of the invention if Si-containing foam stabilizers, based on the total amount of foam stabilizers, are more than 10% by weight, in particular more than 20% by weight and particularly preferably more than 50% by weight. are contained in the composition according to the invention.

Another subject of the invention is a process for the production of PU foams, in particular PU rigid foams, based on foamable reaction mixtures containing polyisocyanates, compounds with reactive hydrogen atoms, blowing agents, and optionally other additives, with polyester-polysiloxane block copolymers being used, preferably as previously described in more detail, in particular as previously described in more detail in the preferred embodiments.

The process according to the invention for the production of PU foams can be carried out according to the known methods, e.g. by hand mixing or preferably with the aid of foaming machines. If the process is carried out using foaming machines, high-pressure or low-pressure machines can be used. The process according to the invention can be carried out either batchwise or continuously.

A preferred rigid PU foam formulation for the purposes of this invention has a density of 5 to 900 kg/m ³ and has the composition given in Table 1.

Table 1 :

Composition of a preferred PU rigid foam formulation

For further preferred embodiments and configurations of the method according to the invention, reference is also made to the statements made above in connection with the composition according to the invention. A further object of the present invention is a PU foam, in particular a rigid PU foam, produced by the aforementioned method according to the invention, in particular using a composition according to the invention.

If the PU foam according to the invention, in particular PU rigid foam, has a density of 5 to 900 kg/m ³ , preferably 5 to 350 kg/m ³ , in particular 10 to 200 kg/m ³ , this is a preferred embodiment of the invention .

Another object of the present invention relates to the use of PU foam according to the invention, in particular PU rigid foam, as mentioned above, as insulating material and/or as a construction material, in particular in construction applications, in particular in spray foam or in the cooling area, as acoustic foam for sound absorption, as packaging foam, as headliners for automobiles or pipe coatings for tubes.

Another object is the use of polyester-polysiloxane block copolymers according to the invention, in particular as defined in one of the claims, in the production of PU foams, preferably rigid PU foams, in particular using a composition according to the invention, in particular as defined in one of the claims of the invention, the polyester-polysiloxane block copolymers being used in particular as foam-stabilizing components in the production of PU foams, preferably PU rigid foams. Preference is given to reducing the flammability of PU foam, preferably rigid PU foam, in particular to improving the fire resistance of the PU foam, preferably the flame resistance and/or reducing the height of the flame, in particular to meeting the fire protection standard of at least B2 according to DIN 4102-1:1998-05.

A preferred composition according to the invention contains the following components: a) polyester-polysiloxane block copolymers according to the invention b) isocyanate-reactive components, in particular polyols c) at least one polyisocyanate and/or polyisocyanate prepolymer d) a catalyst which promotes the reaction of polyols b) with the isocyanates c) accelerates or controls e) optionally another silicon-containing compound as surfactant f) one or more blowing agents g) optionally further additives, fillers, flame retardants, etc.

According to a preferred embodiment of the invention, a component having at least 2 isocyanate-reactive groups, preferably a polyol component, a catalyst and a polyisocyanate and/or a polyisocyanate prepolymer are used to produce the PU foams. In this case, the catalyst is in particular via the polyol component brought in. Suitable polyol components, catalysts and polyisocyanates and/or polyisocyanate prepolymers are known per se, but are also described further below.

Polyols suitable as the isocyanate-reactive component or polyol component b) for the purposes of the present invention are all organic substances having one or more groups which are reactive toward isocyanates, preferably OH groups, and preparations thereof. Preferred polyols are all for the production of polyurethane systems, in particular polyurethane coatings, polyurethane elastomers or foams; commonly used polyetherpolyols and/or polyesterpolyols and/or hydroxyl-containing aliphatic polycarbonates, in particular polyetherpolycarbonatepolyols and/or polyols of natural origin, so-called “natural oil-based polyols” (NOPs). The polyols usually have a functionality of 1.8 to 8 and number-average molecular weights in the range from 500 to 15,000. The polyols with OH numbers in the range from 10 to 1200 mg KOH/g are usually used.

Polyols or mixtures thereof are preferably used to produce PU rigid foams, with the proviso that at least 90 parts by weight of the polyols present, based on 100 parts by weight of polyol component, have an OH number greater than 100, preferably greater than 150, in particular greater than 200 exhibit. The basic difference between flexible foam and rigid foam is that flexible foam shows elastic behavior and can be reversibly deformed. If the flexible foam is deformed by the application of force, it returns to its original shape as soon as the application of force is removed. Hard foam, on the other hand, is permanently deformed.

Polyether polyols can be prepared by known processes, for example by anionic polymerization of alkylene oxides in the presence of alkali metal hydroxides, alkali metal alcoholates or amines as catalysts and with the addition of at least one starter molecule that preferably contains 2 or 3 reactive hydrogen atoms or by cationic polymerization of alkylene oxides in the presence of Lewis -Acids such as antimony pentachloride or boron trifluoride etherate or by double metal cyanide catalysis. Suitable alkylene oxides contain 2 to 4 carbon atoms in the alkylene radical. Examples are tetrahydrofuran, 1,3-propylene oxide, 1,2- or 2,3-butylene oxide; ethylene oxide and 1,2-propylene oxide are preferably used. The alkylene oxides can be used individually, cumulatively, in blocks, alternately one after the other, or as mixtures. In particular, compounds with at least 2, preferably 2 to 8, hydroxyl groups or with at least two primary amino groups in the molecule are used as starter molecules. Examples of starter molecules that can be used are water, di-, tri- or tetrahydric alcohols such as ethylene glycol, 1,2- and 1,3-propanediol, diethylene glycol, dipropylene glycol, glycerol, trimethylolpropane, pentaerythritol, castor oil, etc., higher polyfunctional polyols, in particular sugar compounds such as glucose, sorbitol, mannitol and sucrose, polyhydric phenols, resols such as oligomeric condensation products of phenol and formaldehyde and Mannich condensates of phenols, formaldehyde and dialkanolamines and melamine, or amines such as aniline, EDA, TDA, MDA and PMDA , particularly preferably TDA and PMDA. Choosing the right one Starter molecule depends on the particular area of application of the resulting polyether polyol in polyurethane production.

Polyester polyols are based on esters of polybasic aliphatic or aromatic carboxylic acids, preferably having 2 to 12 carbon atoms. Examples of aliphatic carboxylic acids are succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, decanedioic acid, maleic acid and fumaric acid. Examples of aromatic carboxylic acids are phthalic acid, isophthalic acid, terephthalic acid and the isomeric naphthalenedicarboxylic acids. The polyester polyols are obtained by condensing these polybasic carboxylic acids with polyhydric alcohols, preferably diols or triols having 2 to 12, particularly preferably 2 to 6, carbon atoms, preferably trimethylolpropane and glycerol.

Polyether polycarbonate polyols are polyols containing carbon dioxide bound as a carbonate. Since carbon dioxide is produced in large quantities as a by-product in many processes in the chemical industry, the use of carbon dioxide as a comonomer in alkylene oxide polymerizations is of particular commercial interest. Partial replacement of alkylene oxides in polyols with carbon dioxide has the potential to significantly reduce the cost of polyol production. In addition, the use of CO2 as a comonomer is ecologically very advantageous, since this reaction represents the conversion of a greenhouse gas into a polymer. The production of polyether polycarbonate polyols by addition of alkylene oxides and carbon dioxide onto H-functional starter substances using catalysts has been known for a long time. Various catalyst systems can be used here: The first generation represented heterogeneous zinc or aluminum salts, as described, for example, in US Pat. No. 3,900,424 or US Pat. No. 3,953,383. Furthermore, mono- and binuclear metal complexes have been used successfully for the copolymerization of CO2 and alkylene oxides (WO 2010/028362, WO 2009/130470, WO 2013/022932 or WO 2011/163133). The most important class of catalyst systems for the copolymerization of carbon dioxide and alkylene oxides are the double metal cyanide catalysts, also referred to as DMC catalysts (US-A 4500704, WO 2008/058913). Suitable alkylene oxides and H-functional starter substances are those which are also used for the preparation of carbonate-free polyether polyols, as described above.

Polyols based on renewable raw materials "Natural oil-based polyols" (NOPs) for the production of PU foams are of increasing interest and are already widely used in view of the long-term limited availability of fossil resources, namely oil, coal and gas, and against the background of rising crude oil prices described in such applications (WO 2005/033167; US 2006/0293400, WO 2006/094227, WO 2004/096882, US 2002/0103091, WO 2006/116456 and EP 1678232). A number of these polyols from various manufacturers are now available on the market (WO 2004/020497, US 2006/0229375, WO 2009/058367). Depending on the basic raw material (e.g. soybean oil, palm oil or castor oil) and the subsequent processing, polyols with different properties result. Here you can Essentially, two groups can be distinguished: a) polyols based on renewable raw materials, which are modified to such an extent that they can be used 100% for the production of polyurethanes (WO 2004/020497, US 2006/0229375); b) polyols based on renewable raw materials which, due to their processing and properties, can only replace the petrochemical-based polyol to a certain extent (WO 2009/058367).

The so-called packed polyols (polymer polyols) represent a further class of usable polyols. These are characterized in that they contain solid organic fillers up to a solids content of 40% or more in disperse distribution. Among others, SAN, PHD and PIPA polyols can be used. SAN polyols are highly reactive polyols containing a dispersed styrene/acrylonitrile (SAN)-based copolymer. PHD polyols are highly reactive polyols which also contain polyurea in dispersed form. PIPA polyols are highly reactive polyols containing a polyurethane in dispersed form, e.g., formed by the in situ reaction of an isocyanate with an alkanolamine in a conventional polyol.

A further class of polyols which can be used are those which are obtained as prepolymers by reacting polyol with isocyanate in a molar ratio of preferably 100:1 to 5:1, preferably 50:1 to 10:1. Such prepolymers are preferably prepared as a solution in the polymer, with the polyol preferably corresponding to the polyol used to produce the prepolymers.

Another class of polyols that can be used are so-called recycling polyols, ie polyols that are obtained from the recycling of polyurethanes. Recycling polyols are known per se. In this way, polyurethanes can be split by solvolysis and thus brought into a soluble form. Almost all chemical recycling processes for polyurethanes use such reactions, e.g. B. glycolysis, hydrolysis, acidolysis or aminolysis, with a variety of process variants are known in the art. The use of recycling polyols represents a preferred embodiment of the invention.

A preferred ratio of isocyanate and polyol, expressed as the formulation index, i.e. as the stoichiometric ratio of isocyanate groups to isocyanate-reactive groups (e.g. OH groups, NH groups) multiplied by 100, is in the range of 10 to 1000, preferred 40 to 400. An index of 100 represents a 1 to 1 molar ratio of the reactive groups.

One or more organic polyisocyanates having two or more isocyanate functions are preferably used as isocyanate components or polyisocyanate c). One or more polyols having two or more isocyanate-reactive groups are preferably used as polyol components.

Isocyanates suitable as isocyanate components for the purposes of this invention are all isocyanates which contain at least two isocyanate groups. In general, all known in itself aliphatic, cycloaliphatic, arylaliphatic and preferably aromatic polyfunctional isocyanates can be used. Isocyanates are particularly preferably used in a range from 40 to 400 mol % relative to the sum of the isocyanate-consuming components.

Examples which may be mentioned here are alkylene diisocyanates having 4 to 12 carbon atoms in the alkylene radical, such as 1,12-dodecane diisocyanate, 2-ethyltetramethylene 1,4-diisocyanate, 2-methylpentamethylene 1,5-diisocyanate, tetramethylene 1,4-diisocyanate and preferably hexamethylene diisocyanate -1,6 (HMDI), cycloaliphatic diisocyanates such as cyclohexane-1,3- and 1-4-diisocyanate and any mixtures of these isomers, 1-isocyanato-3,35-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate or IPDI for short ), 2,4- and 2,6-hexahydrotoluylene diisocyanate and the corresponding isomer mixtures, and preferably aromatic di- and polyisocyanates, such as 2,4- and 2,6-toluene diisocyanate (TDI) and the corresponding isomer mixtures, naphthalene diisocyanate, diethyltoluene diisocyanate, mixtures from 2,4'- and 2,2'-diphenylmethane diisocyanates (MDI) and polyphenylpolymethylene polyisocyanates (crude MDI) and mixtures of crude MDI and toluene diisocyanates (TDI). The organic di- and polyisocyanates can be used individually or in the form of their mixtures. Corresponding “oligomers” of the diisocyanates can also be used (IPDI trimer based on isocyanurate, biurete-urethdione.) It is also possible to use prepolymers based on the isocyanates mentioned above.

It is also possible to use isocyanates which have been modified by the incorporation of urethane, uretdione, isocyanurate, allophanate and other groups, so-called modified isocyanates.

Particularly suitable organic polyisocyanates and therefore particularly preferably used are various isomers of toluene diisocyanate (2,4- and 2,6-toluene diisocyanate (TDI), in pure form or as isomer mixtures of different composition), 4,4'-diphenylmethane diisocyanate (MDI), that so-called "crude MDI" or "polymeric MDI" (contains not only the 4,4'- but also the 2,4'- and 2,2'-isomers of MDI and polynuclear products) as well as the binuclear product referred to as "pure MDI". from predominantly 2,4'- and 4,4'-isomer mixtures or their prepolymers. Examples of particularly suitable isocyanates are listed, for example, in EP 1712578, EP 1161474, WO 00/58383, US 2007/0072951, EP 1678232 and WO 2005/085310, to which reference is made here in its entirety. d) catalysts

Suitable catalysts d) for the purposes of the present invention are all compounds which are able to accelerate the reaction of isocyanates with OH functions, NH functions or other isocyanate-reactive groups. The usual catalysts known from the prior art can be used here, including, for example, amines (cyclic, acyclic; monoamines, diamines, oligomers with one or more amino groups), ammonium compounds, organometallic compounds and metal salts, preferably those of tin, iron , bismuth, potassium and zinc. In particular, mixtures of several components can be used as catalysts.

Optional component e) can be further surface-active silicon-containing compounds that serve as an additive in order to optimize the desired cell structure and the foaming process. Therefore, such additives are also called foam stabilizers. Within the scope of this invention, all Si-containing compounds that support foam production (stabilization, cell regulation, cell opening, etc.) can be used here. These compounds are well known from the prior art.

All known compounds which are suitable for the production of PU foam can be used as further surface-active Si-containing compounds.

Corresponding siloxane structures that can be used within the meaning of this invention are described, for example, in the following patent specifications, although the use there is only described in classic PU foams, as molded foam, mattresses, insulation material, construction foam, etc.:

CN 103665385, CN 103657518, CN 103055759, CN 103044687, US 2008/0125503, US 2015/0057384, EP 1520870 A1, EP 1211279, EP 0867465, EP 0275563. of the disclosure of the present invention.

The use of blowing agents f) is basically optional, depending on which foaming process is used. Chemical and physical blowing agents can be used. The choice of propellant depends heavily on the type of system.

Depending on the amount of blowing agent used, a high or low density foam is produced. In this way, foams with densities of 5 kg/m ³ to 900 kg/m ³ can be produced. Preferred densities are 5 to 350, particularly preferably 10 to 200 kg/m ³ , in particular 20 to 150 kg/m ³ .

Corresponding compounds with suitable boiling points can be used as physical blowing agents. Chemical blowing agents that react with NCO groups and release gases, such as water or formic acid, can also be used. Particularly preferred blowing agents for the purposes of this invention include hydrocarbons having 3, 4 or 5 carbon atoms, hydrofluoroolefins (HFO), hydrohaloolefins and/or water.

All substances known from the prior art that are used in the production of polyurethanes, in particular PU foams, such as crosslinkers and chain extenders, stabilizers against oxidative degradation (so-called antioxidants), flame retardants can be used as additives g). , surfactants, biocides, cell refining additives, cell openers, solid fillers, antistatic additives, nucleating agents, thickeners, dyes, pigments, color pastes, fragrances, emulsifiers, etc.

As flame retardants, the composition according to the invention can contain all known flame retardants suitable for the production of polyurethane foams. Suitable flame retardants for the purposes of this invention are preferably liquid organic phosphorus compounds, such as halogen-free organic phosphates, e.g. triethyl phosphate (TEP), halogenated phosphates, e.g. tris(1-chloro-2-propyl) phosphate (TCPP) and tris(2-chloroethyl) phosphate (TCEP) and organic phosphonates, e.g. dimethyl methane phosphonate (DMMP), dimethyl propane phosphonate (DMPP), or solids such as ammonium polyphosphate (APP) and red phosphorus. Also suitable as flame retardants are halogenated compounds, e.g. halogenated polyols, and solids, such as expandable graphite, aluminum oxides, antimony compounds and melamine.

The use of the polyester-polysiloxane block copolymers according to the invention enables the reduction of flame retardants, which leads to unsatisfactory results with conventional foam stabilizers.

The objects according to the invention have been and will be described below by way of example, without the invention being restricted to these exemplary embodiments. If ranges, general formulas or compound classes are given, they should not only include the corresponding ranges or groups of compounds that are explicitly mentioned, but also all sub-ranges and sub-groups of compounds that are obtained by removing individual values (ranges) or compounds be able. If documents are cited in the context of the present description, their content, in particular with regard to the facts in which the document was cited, should belong entirely to the disclosure content of the present invention. Unless otherwise stated, percentages are percentages by weight. If mean values are given, they are weight averages unless otherwise stated. If parameters are given that were determined by measurement, the measurements were carried out at a temperature of 25 °C and a pressure of 101,325 Pa, unless otherwise stated.

The present invention is described by way of example in the examples listed below, without the invention, the scope of which results from the entire description and the claims, being restricted to the embodiments mentioned in the examples. Examples:

Example 1: Synthesis of polyester-polysiloxane block copolymers

All reactions were carried out under an inert gas atmosphere.

Block copolymer A:

813.9 g of 2-allyloxyethanol (CAS: 111-45-5) were placed in a 5 L three-necked flask with a KPG stirrer, thermometer and dropping funnel and heated to 100.degree. Then 1.5 g of a toluene solution of the Karstedt catalyst (w(Pt)=2%) were added. Then 2186.1 g of a siloxane of the general formula Me3SiO(SiMe2O)n(SiMeHO)3SiMe3 were metered in over two hours. An exothermic reaction started. The reaction temperature was maintained between 100 and 110°C. After the metered addition was complete, the mixture was stirred for a further 2 hours. Complete conversion of the SiH functions was determined by gas volumemetry. The reaction mixture was then heated to 130° C. and freed from volatile constituents at 1 mbar for 1 hour. A clear, slightly yellowish liquid (stage 1) was obtained.

1175 g of the 1st Level together with 825 g s-Caprolactone (CAS: 502-44-3), 500 g Dilactid (CAS: 95-96-5) and 2.5 g KOSMOS® 29 (tin catalyst from Evonik) in a 5 L - Submitted a three-necked flask with a KPG stirrer and thermometer. The mixture was stirred at 140° C. for 5 h. A liquid polyester-polysiloxane block copolymer was obtained.

Block copolymer B:

500.4 g of 2-allyloxyethanol (CAS: 111-45-5) were placed in a 5 L three-necked flask with a KPG stirrer, thermometer and dropping funnel and heated to 100.degree. Then 1.5 g of a toluene solution of the Karstedt catalyst (w(Pt)=2%) were added. Then 2449.6 g of a siloxane of the general formula Me3SiO(SiMe2O)5i(SiMeHO)ySiMe3 were metered in over two hours. An exothermic reaction started. The reaction temperature was maintained between 100 and 110°C. After the metered addition was complete, the mixture was stirred for a further 2 hours. Complete conversion of the SiH functions was determined by gas volumemetry. The reaction mixture was then heated to 130° C. and freed from volatile constituents at 1 mbar for 1 hour. A clear, slightly yellowish liquid was obtained (stage 1).

1288 g of the 1st Stage together with 621 g s-Caprolactone (CAS: 502-44-3), 391 g Dilactide (CAS: 95-96-5) and 2.3 g KOSMOS® 29 (tin catalyst from Evonik) in a 5 L - Submitted a three-necked flask with a KPG stirrer and thermometer. The mixture was stirred at 140° C. for 5 h. A liquid polyester-polysiloxane block copolymer was obtained.

Block copolymer C:

1175 g of the 1st Step from synthesis example 1 (see block copolymer A) together with 825 g s-caprolactone (CAS: 502-44-3), 500 g y-butyrolactone (CAS: 96-48-0) and 2.5 g KOSMOS® 29 (Tin catalyst from Evonik) in a 5 L three-necked flask with KPG stirrer and thermometer. The mixture was stirred at 140° C. for 5 h. A liquid polyester-polysiloxane block copolymer was obtained.

Block copolymer D:

1288 g of the 1st Step from synthesis example 2 (see block copolymer B) together with 621 g s-caprolactone (CAS: 502-44-3), 391 g y-butyrolactone (CAS: 96-48-0) and 2.3 g KOSMOS® 29 (tin -Catalyst from Evonik) in a 5 L three-necked flask with a KPG stirrer and thermometer. The mixture was stirred at 140° C. for 5 h. A liquid polyester-polysiloxane block copolymer was obtained.

Example 2: PUR rigid foam

The following foam formulation was used for the application-related comparison:

*Daltolac® R 471 from Huntsman, OH number 470 mg KOH/g

**POLYCAT® 8 from Evonik Operations GmbH

*** Polyester-polysiloxane block copolymers as described in Example 1 or polyether siloxanes

Company Evonik Operations GmbH as a reference

****Polymeric MDI, 200 mPa*s, 31.5% NCO, functionality 2.7.

The comparative foamings were carried out using the hand mixing method. For this purpose, polyol, catalysts, water, surfactant and blowing agent were weighed into a beaker and mixed with a plate stirrer (6 cm diameter) at 1000 rpm for 30 s. The amount of propellant evaporated during the mixing process was determined by weighing again and replenished. The MDI was then added, the reaction mixture was stirred with the stirrer described for 7 s at 2500 rpm and immediately transferred into an open mold measuring 27.5×14×14 cm (W×H×D).

After 10 minutes, the foams were removed from the mold. The foams were analyzed one day after foaming. The pore structure and the surface were assessed subjectively using a scale from 1 to 10, with 10 representing an (idealized) undisturbed, very fine foam and 1 representing an extremely severely disturbed, coarse foam. The results are summarized in the following table:

The results show that with the block copolymers A-D pore structures and foam qualities can be achieved that are on the same level as or better than those of polyethersiloxane-based foam stabilizers. Density, compressive strength and the thermal insulation capacity are not or only insignificantly influenced by the block copolymers according to the invention and are on the same level as polyethersiloxane-based foam stabilizers.

Example 3: PUR rigid foam

The following foam formulation was used for the application-related comparison:

*Daltolac® R 471 from Huntsman, OH number 470 mg KOH/g

**POLYCAT® 8 from Evonik Operations GmbH

Company Evonik Operations GmbH as a reference

****Polymeric MDI, 200 mPa*s, 31.5% NCO, functionality 2.7.

The comparative foamings were carried out using the hand mixing method. For this purpose, polyol, catalysts, water, surfactant, flame retardant and blowing agent were weighed into a beaker and mixed with a plate stirrer (6 cm diameter) at 1000 rpm for 30 s. The amount of propellant evaporated during the mixing process was determined by weighing again and replenished. Now the MDI was added, the reaction mixture with that described Stirred with stirrer for 7 s at 2500 rpm and immediately transferred into an open mold measuring 27.5×14×14 cm (W×H×D).

After 10 minutes, the foams were removed from the mold. One day after foaming, the fire behavior was determined using a small burner test (B2) in accordance with DIN 4102-1:1998-05.

The results are summarized in the following table:

The results show that with the block copolymers A-D, a lower flame height can be achieved compared to conventional polyethersiloxanes and thus an improvement in the fire behavior and the fire protection standard of at least B2 can be met.

All other foam properties relevant for use are not or only insignificantly influenced by the copolymers according to the invention.

Example 4: (PIR) polyisocyanurate rigid foam

The following foam formulation was used for the application-related comparison:

*Stepanpol® PS 2352 from Stepan, OH number 250 mg KOH/g

**POLYCAT® 5 from Operations GmbH ***KOSMOS® 75 from Operations GmbH

****Polyester-polysiloxane block copolymers as described in Example 1 or polyether siloxanes from Evonik Operations GmbH as a reference

*****Polymeric MDI, 200 mPa*s, 31.5% NCO, functionality 2.7.

The comparative foamings were carried out using the hand mixing method. For this purpose, polyol, catalysts, water, surfactant, flame retardant and blowing agent were weighed into a beaker and mixed with a plate stirrer (6 cm diameter) at 1000 rpm for 30 s. The amount of propellant evaporated during the mixing process was determined by weighing again and replenished. The MDI was then added, the reaction mixture was stirred with the stirrer described for 5 s at 3000 rpm and immediately transferred into an open mold measuring 27.5×14×14 cm (W×H×D).

After 10 minutes, the foams were removed from the mold. One day after foaming, the foams were subjected to a cone calorimeter test according to ISO 5660-1 AMD 1:2019-08, and the burning time, defined as the time between the ignition of the foam and the flame going out, was determined at a heating rate of 25 kW/m ² .

The results are summarized in the following table:

The results show that with the block copolymers A-D a shorter burning time can be achieved compared to conventional polyethersiloxanes and thus an improvement in the fire behavior.

Claims

Patent Claims:

1. Composition for the production of PU foam, in particular PU rigid foam, comprising at least one isocyanate component, a polyol component, blowing agent, optionally a catalyst which catalyzes the formation of a urethane or isocyanurate bond, characterized in that the composition is polyester -Polysiloxane block copolymers includes.

2. Composition according to claim 1, characterized in that polyester-polysiloxane

formula 1

R ³ = identical or different polyester radicals, preferably polyester radicals of the general formula 2,

R ⁵ = identical or different divalent alkyl radicals which are optionally interrupted by one or more oxygen atoms, preferably - (CH2) 3-, - (CH2) B, - (CH ₂ ) 3OCH ₂ CH2- or - (CH ₂ ) 3OCH ₂ CH(CH3)-

R ^e = O or NH or NMe, preferably O,

R ⁷ = identical or different divalent alkyl radicals having 1 to 20 carbon atoms, preferably alkyl radicals of the general formula -[CR ⁹ 2]e-,

R ⁸ = identical or different radicals of the general formula -C(O)R ¹⁰ or H, preferably H, R ¹⁰ = identical or different alkyl radicals having 1 to 16 carbon atoms, preferably methyl, R ⁴ = identical or different polyether radicals, preferably identical or different

Polyether residues of formula 3

R ¹¹ = identical or different divalent alkyl radicals having 2 to 12 carbon atoms, preferably divalent alkyl radicals having 3 to 6 carbon atoms, in particular -(CH2)3-,

R ¹³ = identical or different radicals from the group: -C(O)R ¹⁰ , H and alkyl radicals with 1-8 carbon atoms, preferably -C(O)CH3, H or methyl, a=5-200, preferably 5-100 , particularly preferably 10 - 80, b = 1 - 20, preferably 1 - 15, particularly preferably 2 - 10, c = 0 - 20, preferably 0 - 15, particularly preferably 0, d = 2 to 80, preferably 2 to 60, particularly preferably 3 to 40 e=1-16, preferably 1 to 12, particularly preferably 1 to 6 x=0 to 80, preferably 0 to 60, particularly preferably 3 to 40 y=0 to 80, preferably 0 to 60, particularly preferably 3 to 40 z=0 to 60, preferably 0 to 20, particularly preferably 0, with the proviso that x+y+z>2, and with the proviso that at least one radical R ³ must be present in the molecule, and preferred at least two different radicals R ⁷ are present in the molecule. Composition according to Claim 1 or 2, characterized in that the polyester-polysiloxane block copolymers are obtained by reacting cyclic esters, their cyclic dimers or higher analogues with alcohol- and/or amino-functional siloxanes, preferably derived from formulas 1 and 2. Composition according to one of Claims 1 to 3, characterized in that at least two or more different cyclic esters, in particular selected from propiolactone, lactide, caprolactone, butyrolactone or valerolactone, are used to produce the polyester-polysiloxane block copolymers. Composition according to any one of Claims 1 to 4, characterized in that the polyester-polysiloxane block copolymers are present in a total amount of from 0.01 to 15 parts, preferably 0.1 to 10 parts, particularly preferably 0.1 to 5 parts, based on 100 parts of polyols are used. Composition according to one of Claims 1 to 5, characterized in that the composition contains hydrocarbons with 3, 4 or 5 carbon atoms, preferably cyclopentane, isopentane and/or n-pentane, fluorocarbons preferably HFC 245fa, HFC 134a and/or or HFC 365mfc, perfluorinated compounds such as perfluoropentane, perfluorohexane and/or perfluorohexene, hydrofluoroolefins or hydrohaloolefins, preferably 1234ze, 1234yf, 1224yd, 1233zd(E) and/or 1336mzz, water, oxygen-containing compounds such as methyl formate, acetone and/or dimethoxymethane, and/or chlorinated hydrocarbons, preferably dichloromethane and/or 1,2-dichloroethane. Composition according to one of Claims 1 to 6, characterized in that the polyester-polysiloxane block copolymer also contains polyether side chains in addition to the polyester side chains. Composition according to any one of claims 1 to 7, characterized in that exclusively polyether-containing siloxane-based foam stabilizers, based on the total amount of foam stabilizers, less than 15 wt .-%, preferably less than 10 wt .-%, in particular less than 5% by weight or not included at all. Composition according to one of Claims 1 to 8, characterized in that Si-containing foam stabilizers, based on the total amount of foam stabilizers, are more than 10% by weight, in particular more than 20% by weight and particularly preferably more than 50% by weight % are included. Process for the production of PU foams, in particular PU rigid foams, based on foamable reaction mixtures containing polyisocyanates, compounds with reactive hydrogen atoms, blowing agents and optionally other additives, characterized in that polyester-polysiloxane block copolymers are used, preferably as in one of the Claims 1 to 9 as defined, in particular using a composition as defined in any one of claims 1 to 9. PU foam, in particular PU rigid foam, produced by the method according to claim 10. Use of PU foam, in particular PU rigid foam, according to claim 11 as an insulating material and/or as a construction material, in particular in construction applications, in particular in spray foam or in the cooling area, as acoustic foam for sound absorption, as packaging foam, as headlining for automobiles or pipe sheathing for tubes. 21 Use of polyester-polysiloxane block copolymers, in particular as defined in any one of claims 2 to 4, in the production of PU foams, preferably PU rigid foams, in particular using a composition according to any one of claims 1 to 9. Use according to claim 13 as a foam-stabilizing component in the production of PU foams, preferably PU rigid foams. Use according to claim 13 or 14 to reduce the flammability of PU foam, preferably PU rigid foam, in particular to improve the fire resistance of the PU foam, preferably the flame resistance and/or reduce the flame height, in particular to meet the fire protection standard of at least B2 according to DIN 4102-1 .