Method for producing sioc-linked, linear polydialkylsiloxane-polyether block copolymers and the use thereof

Abstract

The invention relates to a method for producing SiOC-linked, linear polydialkylsiloxane-polyoxyalkylene block copolymers having repeating (AB) units, comprising the reaction of a linear, α,ω-(SiH)-functional polydialkylsiloxane (a) with a linear, α,ω-(OH)-functional polyoxyalkylene (b), using one or more compounds of elements of the third main group and / or third subgroup as catalyst (c), the two reactants (a) and (b) being preferably reacted in equimolar amounts and with controlled hydrogen formation until quantitative SiH conversion.

Description

[0001] Process for the preparation of SiOC-linked, linear polydialkylsiloxane-polyether block copolymers and their use

[0002] The present invention lies in the fields of silicone chemistry and polyurethane chemistry and relates to a process for the preparation of SiOC-linked, linear polydialkylsiloxane-polyoxyalkylene block copolymers with repeating (AB) units and their use in the production of polyurethanes (PU for short).

[0003] The process principle for producing SiOC-linked polydialkylsiloxane-polyoxyalkylene block copolymers by reacting SiH-functional polyorganosiloxanes with alcohols or OH-functional polyoxyalkylene polymers using one or more elemental compounds of main group III and / or transition group III as catalyst is known in principle from EP 1460099 B1. Therein, a preferred conversion of at least an equimolar up to a three-fold excess of alcohol groups to SiH groups is described. This process was used to react linear and / or branched polyorganosiloxanes with alcohols and / or OH-functional polyoxyalkylenes.

[0004] Furthermore, a process for producing SiOC-linked, linear polydimethylsiloxane-polyether block copolymers with repeating (AB) units is also known from EP 1935922 B1, wherein the polydimethylsiloxane-polyoxyalkylene block copolymers thus produced are used as surface-active additives for the production of polyurethane foams. EP 1935922 B1 describes the reaction of linear α,co-(SiH)-functional polydimethylsiloxanes with linear, α,co-(OH)-functional polyetherdiols using one or more element compounds of main group III and / or transition group III as catalyst.The process, which can be carried out neat or in the presence of solvent, is essentially characterized in that the (SiH) functions of the polydimethylsiloxane are used in a molar excess of preferably 1.1 to 2.0 relative to the (OH) functions of the polyoxyalkylene and the reaction is continued until no more (SiH) groups can be detected by gas volumetric analysis.

[0005] However, the excessive use of polysiloxane, which is significantly more expensive than the polyetherdiol component, and the subsequent long post-reaction for the quantitative conversion of the excess (SiH) groups is disadvantageous from an economic point of view.

[0006] Therefore, it was the object of the present invention to provide a simple, economically viable and stable process with which the production of SiOC-linked, linear polydialkylsiloxane-polyoxyalkylene block copolymers with repeating (AB) units is made possible reproducibly and with an improved property profile, preferably with the focus on using them as surface-active additives for the production of polyurethane foams, in particular for the production of rigid polyurethane foams.Surprisingly, it has now been found that the use of preferably equimolar amounts of (SiH) functions of a linear, α,co-(SiH)-functional polydialkylsiloxane relative to the (OH) functions of a linear α,co-(OH)-functional polyoxyalkylene, in conjunction with controlled hydrogen evolution according to claim 1, enables the provision of particularly high-molecular-weight products that are of higher quality than those obtainable by the process published in EP 1935922 B1. The controlled hydrogen evolution can be achieved by controlled dosage. Furthermore, the process according to the invention proves to be significantly more stable and less prone to errors.

[0007] The invention relates to a process for the preparation of SiOC-linked, linear polydialkylsiloxane-polyoxyalkylene block copolymers having repeating (AB) units, comprising the reaction of a linear, a,co-(SiH)-functional polydialkylsiloxane (a) with a linear a,co-(OH)-functional polyoxyalkylene (b), using one or more element compounds of main group III and / or transition group 3 as catalyst (c), optionally in the presence of a solvent (d), wherein the two reactants (a) and (b) are preferably reacted in equimolar amounts and with controlled hydrogen evolution until quantitative SiH conversion is achieved.

[0008] Reactant (a) in the sense of this invention is: linear a,co-(SiH)-functional polydialkylsiloxane.

[0009] Reactant (b) in the sense of this invention is: linear a,co-(OH)-functional polyoxyalkylene.

[0010] If the linear a,co-(SiH)-functional polydialkylsiloxane used in the process according to the invention has SiH values ​​between 0.25 and 3.0 mol / kg, preferably between 0.5 and 2.0 mol / kg, in particular between 0.75 and 1.5 mol / kg, then a particularly preferred embodiment of the invention is present. The determination of the molar amount of SiH units in the linear a,co-(SiH)-functional polydialkylsiloxanes is based on the known method of alkali-catalyzed SiH value determination.

[0011] A further object of the invention are the SiOC-linked, linear polydialkylsiloxane-polyether block copolymers with repeating (AB) units, prepared according to the process of the invention.

[0012] The terms “SiOC-linked, linear polydialkylsiloxane-polyether block copolymers” and “SiOC-linked, linear polydialkylsiloxane-polyoxyalkylene block copolymers” are used synonymously in the context of this invention.

[0013] The invention further relates to the use of the SiOC-linked, linear polydialkylsiloxane-polyether block copolymers with repeating (AB) units produced by the process according to the invention as surface-active additives, in particular as cell openers, for the production of polyurethane foams (PU foams), preferably rigid polyurethane foams, in particular rigid polyurethane foams with a high degree of open cell density. A particularly preferred rigid polyurethane foam is one-component PU canned foam (construction foam, assembly foam, one-component foam / OCF). Particular preference is given to rigid polyurethane foams for which a high degree of open cell density is advantageous, such as open-cell spray foam, packaging foam, roof lining foam, pipe insulation foam, floral foam, and / or thermoformable rigid foams, etc.

[0014] A further subject matter of the invention is a polyurethane foam, preferably rigid polyurethane foam, in particular a rigid polyurethane foam with high open cell density, produced using SiOC-linked, linear polydialkylsiloxane-polyether block copolymers according to the invention with repeating (AB) units.

[0015] A further subject matter of the invention is the use of the polyurethane foam according to the invention, preferably rigid polyurethane foam, in particular rigid polyurethane foam with a high degree of open cell density, for producing foam moldings, spray foam, insulating foam, sealing compounds, adhesive compounds, insulating compounds, assembly compounds, and / or filling compounds.

[0016] Short description of the figures FIG 1 to FIG 6:

[0017] FIG 1 shows the course of the gas volume released by the reaction progress as a function of the added siloxane mass for Example 1 from the experimental part, each as target and actual conversion.

[0018] FIG 2 shows the course of the gas volume released by the reaction progress as a function of the added siloxane mass for Example 2 from the experimental part, each as target and actual conversion.

[0019] FIG 3 shows the course of the gas volume released by the reaction progress as a function of the added siloxane mass for Example 3 from the experimental part, each as target and actual conversion.

[0020] FIG 4 shows the course of the gas volume released by the reaction progress as a function of the added siloxane mass for Example 4 from the experimental part, each as target and actual conversion.

[0021] FIG 5 shows the course of the gas volume released by the reaction progress as a function of the added siloxane mass for Example 5 from the experimental part, each as target and actual conversion.

[0022] FIG. 6 shows the deviation of the target conversion from the actual conversion in % as a function of the metered siloxane mass for Examples 1 to 5 from the experimental section. The linear α,α-(SiH)-functional polydialkylsiloxanes used in the process according to the invention are known per se. They can be equilibrated in a known manner using any prior art method (preferably acidic).

[0023] They preferably have weight-average molecular weights between approximately 650 and 7000 g / mol, preferably between 1000 and 6000 g / mol, in particular between approximately 1500 and 4500 g / mol. This corresponds to a preferred embodiment of the invention. The determination of the average molecular weights is based on known methods of GPC analysis.

[0024] Preferably, linear a,co-(SiH)-functional polydialkylsiloxanes of the general formula (I) are used:

[0025] M' - Da - M' Formula (I) where

[0026] M' = [HR 1 2SiOi / 2]

[0027] D= [R 1 2SiO2 / 2] a = 8 - 100, preferably 10 - 60, particularly preferably 20 - 50,

[0028] R 1 = independently of one another identical or different hydrocarbon radicals having 1 - 20 carbon atoms, preferably methyl, ethyl, propyl or butyl, particularly preferably methyl.

[0029] The linear α,α-(OH)-functional polyoxyalkylenes used in the process according to the invention (hereinafter also referred to simply as "polyetherdiols" for the purposes of this invention) are also known per se. They can be prepared by any known prior art process. They preferably correspond to the general formula (II):

[0030] HO-(CnH( 2n -m)R 2 mO-)bH Formula (II) b = 1 - 200, preferably 10 - 100, particularly preferably 25 - 60, n = 2 - 4, m = 0 or 1,

[0031] R 2 = independently of one another identical or different hydrocarbon radicals having 1 - 12 carbon atoms, preferably methyl, ethyl, propyl or butyl, particularly preferably methyl or ethyl.

[0032] The polyether diols are preferably addition products of at least one alkylene oxide selected from the group consisting of ethylene oxide, propylene oxide, butylene oxide, dodecene oxide, and / or tetrahydrofuran with difunctional starters such as water, ethylene glycol, or propylene glycol. The polyether diols are preferably composed of at least two monomer units, particularly preferably ethylene oxide and propylene oxide.

[0033] The polyether diols preferably consist essentially of oxyethylene units or oxypropylene units, preferred are mixed oxyethylene and oxypropylene units with an oxyethylene content of about 25 to 70 wt.% and 70 to 25 wt.% oxypropylene content based on the total content of oxyalkylene units.

[0034] The oxyethylene units or oxypropylene units can be structured either randomly or in blocks, but they are preferably structured in blocks.

[0035] The weight-average molecular weight Mw of each polyetherdiol is preferably between about 600 and 10,000 g / mol, more preferably 1,000 to 5,000 g / mol, and particularly preferably 1,500 to 3,500 g / mol. The determination of the average molecular weights is based on known methods for determining the OH number.

[0036] The molar ratio of linear α,α-(SiH)-functional polydialkylsiloxane to linear α,α-(OH)-functional polyoxyalkylene preferably used in the process according to the invention is in the equimolar range. This means the use of preferably equimolar amounts of (SiH) functions of the linear, α,α-(SiH)-functional polydialkylsiloxane relative to the (OH) functions of the linear α,α-(OH)-functional polyoxyalkylene.

[0037] When, in the context of this invention, reference is made to equimolar ratios or equimolar amounts of the two reactants (a) and (b), this specifically encompasses the range from 0.9 to 1.10, preferably 0.98 to 1.02, of linear a,co-(SiH)-functional polydialkylsiloxane to linear a,co-(OH)-functional polyoxyalkylene. In particular, this ratio is precisely equimolar, i.e., 1 to 1.

[0038] The total siloxane block content (A) in the SiOC-linked, linear polydialkylsiloxane-polyoxyalkylene block copolymer with repeating (AB) units is preferably between 20 and 60 wt. %, in particular 40 to 50 wt. %, and the content of polyoxyalkylene blocks (B) is preferably between 80 and 40 wt. %, more preferably 60 to 50 wt. It is preferred if the block copolymer has an average weight-average molecular weight Mw of at least 10,000 g / mol to approximately 250,000 g / mol, preferably 15,000 g / mol to approximately 225,000 g / mol, in particular 20,000 g / mol to approximately 200,000 g / mol. The determination of the average molar masses is based on known methods of GPC analysis.

[0039] Depending on the application and the desired product properties, the process can be carried out either in the presence or absence of a solvent. If particularly high-molecular-weight and therefore particularly high-viscosity SiOC-linked copolymers are to be produced, the use of a solvent is particularly advantageous.

[0040] Advantageously used solvents include alkanes, isoalkanes, cycloalkanes and / or alkyl aromatics.

[0041] Alkanes that can be used advantageously are, for example, n-hexane, n-heptane, n-octane, n-nonane, n-decane, n-undecane and / or n-dodecane.

[0042] Cycloalkanes which can be used advantageously are, for example, cyclohexane, methylcyclohexane, cycloheptane, cyclooctane, cyclononane, cyclodecane, cycloundecane, cyclododecane and / or decalin.

[0043] Advantageously used alkyl aromatics are toluene, xylene, cumene, n-propylbenzene, ethylmethylbenzene, trimethylbenzene, solvent naphtha and / or any industrially available alkylbenzenes.

[0044] High-boiling solvents with boiling points > 120°C are preferably used, particularly preferably high-boiling alkylbenzenes.

[0045] The choice of type and quantity of the optional solvent depends on the specific application and can be varied within wide limits.

[0046] In order to achieve particularly good product quality and particularly good efficiency of the process, in a preferred embodiment of the invention, preferably between 40% by weight and 75% by weight of solvent are used in relation to the sum of the amounts of reactants (a), (b) and the amount of solvent (c), particularly preferably between 55% by weight and 65% by weight.

[0047] In a preferred embodiment of the invention, the reaction temperature for preparing the block copolymers according to the invention is preferably from 60°C to 140°C, particularly preferably from 100°C to 120°C.

[0048] The catalysts which can preferably be used in the process according to the invention in a preferred embodiment of the invention are Lewis acid element compounds of main group III, in particular boron-containing and / or aluminum-containing element compounds.

[0049] Of the Lewis acid element compounds of subgroup 3, scandium-containing, yttrium-containing, lanthanum-containing and / or lanthanide-containing Lewis acids are particularly preferred. The element compounds of main group III and / or subgroup 3 can particularly preferably be used as halides, alkyl compounds, fluorine-containing, cycloaliphatic and / or heterocyclic compounds. A preferred embodiment of the invention provides for the use of fluorinated and / or non-fluorinated organoboron compounds as catalysts, in particular those selected insbesondere Tris(Perfluortriphenylboran) [1109-15-5], Bortrifluorid-Etherat [109-63-7], Boran- Triphenylphosphinkomplex [2049-55-0], Triphenylboran [960-71-4], Triethylboran [97-94-9] und Bortrichlorid [10294-34-5], Tris(pentafluorophenyl)-Boroxin (9CI) [223440-98-0], 4, 4, 5, 5,- Tetramethyl-2-(pentafluorophenyl)-1 ,3,2-Dioxaborolan (9CI) [325142-81-2], 2-(Pentafluorophenyl)- 1 ,3,2-Dioxaborolan (9CI) [336880-93-4], Bis(pentafluorophenyl)cyclohexylboran [245043-30-5], Di- 2,4-cyclopentadien-1-yl(pentafluorophenyl)-Boran (9CI) [336881-03-9], (Hexahydro-3a(1 H)- pentalenyl) bis(pentafluorophenyl) boran (9CI) [336880-98-9], 1 ,3-[2-[Bis(pentafluorophenyl)- boryl]ethyl]tetramethyldisiloxan [336880-99-0], 2,4,6-Tris(pentafluorophenyl)borazin (7CI, 8CI, 9CI) [1 110-39-0], 1 ,2-Dihydro-2-(pentafluorophenyl)-1 ,2-azaborin (9CI) [336880-94-5], 2-(Pentafluoro- phenyl)-1 ,3,2-benzodioxaborol (9CI) [336880-96-7], Tris(4-trifluoromethoxyphenyl)boran [336880- 95-6],Tris(3-trifluoromethylphenyl)borane [24455-00-3], tris(4-fluorophenyl)borane [47196-74-7], tris(2,6-difluorophenyl)borane [146355-09-1], tris(3,5-difluorophenyl)borane [154735-09-8], methylium triphenyltetrakis(pentafluorophenyl)borate [136040-19-2] and / or N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate as well as mixtures of the above catalysts can preferably be used.

[0050] A further preferred embodiment of the invention provides that fluorinated and / or non-fluorinated organoaluminium compounds are used as catalysts, in particular those selected from:

[0051] AlCh [7446-70-0], aluminum acetylacetonate [13963-57-0], AlF3 [7784-18-1], aluminum trifluoromethanesulfonate [74974-61-1], di- / so-butylaluminium chloride [1779-25-5], di- / so-butylaluminium hydride [1191-15-7] and / or triethylaluminium [97-93-8] and mixtures thereof.

[0052] A further preferred embodiment of the invention provides that fluorinated and / or non-fluorinated organoscandium compounds are used as catalysts, in particular those selected from:

[0053] Scandium(III) chloride [10361-84-9], scandium(III) fluoride [13709-47-2], scandium(III) hexafluoroacetylacetonate [18990-42-6], scandium(III) trifluoromethanesulfonate [144026-79-9] and / or tris(cyclopentadienyl)scandium [1298-54-0] and mixtures thereof.

[0054] A further preferred embodiment of the invention provides that fluorinated and / or non-fluorinated organoyttrium compounds are used as catalysts, in particular those selected from: tris(cyclopentadienyl)yttrium [1294-07-1], yttrium(III) chloride [10361-92-9], yttrium(III) fluoride [13709-49-4], yttrium(III) hexafluoroacetylacetonate [18911-76-7] and / or yttrium(III) naphthenate [61790-20-3] and mixtures thereof.

[0055] A further preferred embodiment of the invention provides that fluorinated and / or non-fluorinated organolanthanum compounds are used as catalysts, in particular those selected from:

[0056] Lanthanum(III) chloride [10099-58-8], lanthanum(III) fluoride [13709-38-1], lanthanum(III) iodide [13813-22-4], lanthanum(III) trifluoromethanesulfonate [52093-26-2] and / or tris(cyclopentadienyl)lanthanum [1272-23-7] and mixtures thereof.

[0057] A further preferred embodiment of the invention provides that fluorinated and / or non-fluorinated organolanthanoid compounds are used as catalysts, in particular those selected from:

[0058] Cerium(III) bromide [14457-87-5], cerium(III) chloride [7790-86-5], cerium(III) fluoride [7758-88-5], cerium(IV) fluoride [60627-09-0], cerium(III) trifluoroacetylacetonate [18078-37-0], tris(cyclopentadienyl)cerium [1298-53-9], europium(l ll)fluoride [13765-25-8], europium(ll) chloride [13769-20-5], praesodymium(lll)hexafluoroacetylacetonate [47814-20-0], praesodymium(lll)fluoride [13709-46-1], Praesodymium(III)trifluoroacetylacetonate [59991-56-9], samarium(III) chloride [10361-82-7], samarium(III) fluoride [13765-24-7], samarium(III) naphthenate [61790-20-3], samarium(III) trifluoroacetylacetonate [23301-82-8], ytterbium(III) fluoride [13760-80-8], ytterbium(III) trifluoromethanesulfonate [54761-04-5] and / or tris-(cyclopentadienyl)ytterbium [1295-20-1] and mixtures thereof.

[0059] The catalysts are preferably used in amounts of about 0.01 to about 0.2 wt.%, in particular 0.03 to 0.10 wt.%, based on the sum of the amounts of reactants (a) and (b).

[0060] The catalyst(s) can be used homogeneously or as heterogeneous catalyst(s). The catalyst(s) can be added dissolved or suspended. Advantageously, the catalyst can be suspended in a small portion of the solvent or polyetherdiol, or dissolved and added; particularly preferably, it can be added dissolved in the solvent.

[0061] In a preferred embodiment of the process according to the invention, the polyetherdiol is initially introduced and dried under vacuum at elevated temperature, optionally in the presence of the solvent, in order to prevent the potential side reaction of Si-H to Si-OH in the presence of water. This can be carried out, for example, by vacuum distillation. The dehydrogenative coupling can be promoted by establishing a weakly acidic medium. To make the alcohol to be reacted weakly acidic, diammonium phosphate (DAP; 100 to 500 ppm), for example, can be added before, during, or after distillation. In a preferred embodiment of the process according to the invention, the preferably dried polyetherdiol (reactant (b)) is heated to reaction temperature, the catalyst is added, and the mixture is thoroughly mixed. The linear, α,α-(SiH)-functional polydialkylsiloxane (reactant (a)) is then metered in with controlled hydrogen evolution.

[0062] In a preferred embodiment of the process according to the invention, the preferably dried polyetherdiol (reactant (b)) is heated to reaction temperature, the catalyst is added and mixed thoroughly. Then, the siloxane (reactant (a)), diluted with a solvent, is added with controlled hydrogen evolution.

[0063] In a preferred embodiment of the process according to the invention, the preferably dried polyetherdiol (reactant (b)) is heated to reaction temperature, diluted with solvent, and the catalyst is added and mixed thoroughly. The siloxane (reactant (a)) is then metered in with controlled hydrogen evolution.

[0064] In a preferred embodiment of the process according to the invention, the preferably dried polyetherdiol (reactant (b)) is heated to reaction temperature, diluted with solvent, and the catalyst is added and mixed thoroughly. The siloxane (reactant (a)), diluted with a solvent, is then added with controlled hydrogen evolution.

[0065] The following applies to each of these four aforementioned preferred embodiments: The addition is preferably continuous, allowing a controlled reaction progress, which is noticeable by a corresponding continuous gas release. Once the gas release has ceased, the reaction is complete, which can also be verified by sampling and external SiH value determination.

[0066] In another preferred embodiment, the addition of the pure or solvent-diluted siloxane (reactant (a)) in the four embodiments mentioned above can also be carried out in intervals instead of continuously. In this case, the siloxane (reactant (a)) is then added in intervals. This means that after each dosing interval there is a dosing pause, which advantageously lasts until the lack of hydrogen evolution indicates quantitative SiH conversion of the previously dosed portion. Then the next interval is added. The dosage amounts and times per interval are preferably kept constant, but adjustments can be made by the person skilled in the art for the specific application. For example, larger amounts of siloxane can be dosed per interval at the beginning of the synthesis and smaller amounts towards the end, or vice versa.

[0067] During dosing, it is always extremely beneficial to ensure efficient mixing.

[0068] According to the invention, the reaction of reactants (a) and (b) takes place with controlled hydrogen evolution until quantitative SiH conversion is achieved. In the context of this invention, this means that the deviation between the actual conversion and the target conversion is as small as possible, preferably in the range from 0 to 10%, preferably from 0 to 7.5%, and particularly preferably from 0 to 5%. The term target conversion is understood to mean the amount of hydrogen that can be released upon quantitative SiH conversion of the amount of hydrogen siloxane present in the reaction system at any given time. The term actual conversion is understood to mean the amount of hydrogen actually released at any given time. This controlled hydrogen evolution can be achieved by a controlled dosage of component (a) to component (b). If the deviation between the target and actual conversion is too high, for example, the addition rate of component (a) can be throttled.A preferred method for controlling hydrogen evolution is described in detail in the examples section.

[0069] The SiOC-linked, linear polydialkylsiloxane-polyoxyalkylene block copolymers with repeating (AB) units, prepared by the process according to the invention, can be used particularly advantageously as surface-active additives, in particular as cell openers, for the production of polyurethanes, preferably polyurethane foams, in particular for the production of rigid polyurethane foams. Particular preference is given to one-component PU can foam (construction foam, assembly foam, one-component foam / OCF) and / or other rigid polyurethane foams for which a high degree of open-cell density is advantageous (such as open-cell spray foam, packaging foam, roof lining foam, pipe insulation foams, floral foam and / or thermoformable rigid foams, etc.). These uses are therefore also the subject of the present invention.

[0070] For the aforementioned preferred applications, it is preferably desirable that the finished PU foam, preferably rigid PU foam, exhibits minimal change in geometric dimensions during and especially after the curing process. This desirable dimensional stability, i.e., low shrinkage or low post-expansion, can preferably be achieved by a high degree of open-cell foam. At the same time, it is desirable that this open-cell foam does not result in any serious foam defects such as voids: the foam cells should preferably remain fine and not exhibit any coarsening.

[0071] For this reason, it may be advantageous to use a polyol-isocyanate prepolymer in the production of such PU foams. However, it is particularly advantageous to add a cell opener in addition to the foam stabilizer usually present (usually a polyether siloxane). The SiOC-linked, linear polydialkylsiloxane-polyether block copolymers of the invention have proven particularly effective for this application.

[0072] The SiOC-linked, linear polydialkylsiloxane-polyether block copolymers obtainable by the process according to the invention and containing repeating (AB) units can therefore be used with particular advantage as cell openers in the production of polyurethane foams, in particular rigid polyurethane foams. The term "cell opener" is known per se to those skilled in the art in connection with the production of PU foams. Cell openers are understood to be substances that are suitable for, or whose function is to, induce increased open-cell density during the production of a polyurethane foam, preferably rigid polyurethane foam, which would otherwise usually be largely closed-cell (namely, in the case of rigid PU foam, usually less than 30%, preferably less than 20%, particularly preferably less than 10% open cells, based on the total number of cells).The inventive use of SiOC-linked, linear polydialkylsiloxane-polyether block copolymers obtainable by the inventive process, with repeating (AB) units as cell openers, enables a high degree of open-cell density in the resulting PU foam, especially rigid PU foam. The term "high degree of open-cell density" is defined below.

[0073] The use concentration of the SiOC-linked, linear polydialkylsiloxane-polyoxyalkylene block copolymers according to the invention with repeating (AB) units as a surface-active additive, in particular as a cell opener, in the polyurethane foam to be produced, preferably rigid polyurethane foam, is preferably between 0.01 wt.% and 10 wt.%, preferably between 0.05 wt.% and 7 wt.%, particularly preferably between 0.1 wt.% and 5 wt.%, in each case based on the total formulation of the polyurethane foam.

[0074] The term polyurethane foam is known to the person skilled in the art (see, for example, Adam et al., “Polyurethanes”, Ullmann's Encyclopedia of Industrial Chemistry - Paragraph 7”, 2012, Wiley VCH-Verlag, Weinheim).

[0075] A preferred composition according to the invention of a PU foam, preferably rigid polyurethane foam, contains the following components: a) SiOC-linked, linear polydialkylsiloxane-polyoxyalkylene block copolymer according to the invention with repeating (AB) units b) polyol component c) (poly)isocyanate component d) catalyst e) optionally foam stabilizer f) blowing agent g) optionally further additives, preferably fillers, liquid or solid flame retardants, dispersing aids, etc.

[0076] The SiOC-linked, linear polydialkylsiloxane-polyoxyalkylene block copolymer with repeating (AB) units according to the invention is used as a surface-active additive, preferably as a cell opener.

[0077] The terms "polyurethane" and "polyurethane foam" are established technical terms and have long been known to those skilled in the art. For the purposes of the present invention, polyurethane (PU) refers in particular to a product obtainable by reacting a polyisocyanate component with a polyol component.

[0078] In addition to polyurethane, other functional groups such as uretdiones, carbodiimides, isocyanurates, allophanates, biurets, ureas, and / or uretimines can also be formed. Therefore, PU in the context of the present invention refers to both polyurethane and polyisocyanurates, polyureas, as well as polyisocyanate reaction products containing uretdione, carbodiimide, allophanate, biuret, and / or uretimine groups.

[0079] Accordingly, polyurethane foam (PU foam) in the context of the present invention refers to a foam obtained as a reaction product of a polyisocyanate component and a polyol component. In addition to the eponymous polyurethane, other functional groups such as allophanates, biurets, ureas, carbodiimides, uretdiones, isocyanurates, or uretimines can also be formed.

[0080] PU rigid foam (polyurethane rigid foam) is a well-established technical term. The well-known and fundamental difference between flexible foam and rigid foam is that flexible foam exhibits elastic behavior and, consequently, deformation is reversible. Rigid foam, on the other hand, is permanently deformed. Further information on polyurethane rigid foams can be found in the "Kunststoffhandbuch, Volume 7, Polyurethane," Carl Hanser Verlag, 3rd edition 1993, Chapter 6. The terms "foam" and "cellular material" are used synonymously for the purposes of this invention. This also applies accordingly to related terms such as "rigid foam" and "rigid foam material," etc.

[0081] Particularly preferred PU foams within the meaning of the present invention are rigid polyurethane foams, such as in particular one-component can foam, open-cell spray foam, packaging foam, roof lining foam, pipe insulation foam, floral foam, thermoformable rigid foam and / or other rigid polyurethane foams in which a high degree of open cell density is particularly advantageous.

[0082] As polyol component (b), one or more organic compounds having OH groups, SH groups, NH groups and / or NH2 groups, with a functionality of 1.8 to 8, can be used. The polyol component comprises at least one compound having at least two isocyanate-reactive groups selected from OH groups, SH groups, NH groups and / or NH2 groups, in particular OH groups.

[0083] A functionality of, for example, 1.8 can result from mixing at least one compound with a higher functionality, for example greater than or equal to 2, with at least one compound with a functionality of, for example, 1. This can occur in particular when a polyisocyanate component (c) with a functionality greater than 2 or additional crosslinkers are used as optional additives. Corresponding compounds that can usually be used in the production of PU foams are known to the person skilled in the art and are described, for example, in "Kunststoffhandbuch, Volume 7, Polyurethane", Carl Hanser Verlag, 3rd edition 1993, Chapter 3.1. Compounds with OH numbers in the range from 10 to 1200 mg KOH / g are usually used.

[0084] Particularly preferred compounds are all polyether polyols and polyester polyols commonly used for the production of polyurethane systems, in particular polyurethane foams.

[0085] In addition, polyether polycarbonate polyols, natural oil-based polyols (NOPs; described in WO 2005 / 033167, US 2006 / 0293400, WO 2006 / 094227, WO 2004 / 096882, US 2002 / 0103091, WO 2006 / 116456, EP 1678232), filler polyols, prepolymer-based polyols and / or recycling polyols can be used.

[0086] Recycling polyols are polyols obtained from the chemical recycling of polyurethanes, for example, by solvolysis, such as glycolysis, hydrolysis, acidolysis, or aminolysis. The use of recycling polyols represents a particularly preferred embodiment of the invention.

[0087] If the polycomponent contains polyol-isocyanate prepolymers, this is a preferred embodiment of the invention.

[0088] As the isocyanate or polyisocyanate component (c), one or more polyisocyanates with two or more isocyanate groups can generally be used. Suitable polyisocyanates for the purposes of this invention are all organic isocyanates with two or more isocyanate groups, in particular the known aliphatic, cycloaliphatic, arylaliphatic, and preferably aromatic polyfunctional isocyanates.

[0089] 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-ethyl-tetramethylene-1,4-diisocyanate, 2-methyl-pentamethylene-1,5-diisocyanate, tetramethylene-1,4-diisocyanate, pentamethylene diisocyanate (PDI) and preferably hexamethylene-1,6-diisocyanate (HMDI), cycloaliphatic diisocyanates such as cyclohexane-1,3- and -1,4-diisocyanate and the corresponding isomer mixtures, 4,4'-methylenedicyclohexyl diisocyanate (H12MDI), isophorone diisocyanate (IPDI), 2,4- and 2,6-methylcyclohexyl 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, naphthylene diisocyanate, diethyltoluene diisocyanate, 4,4'- or 2,2'- or 2,4'- diphenylmethane diisocyanate (MDI) and polymethylene polyphenyl polyisocyanates (PMDI, “polymeric MDI”).The organic polyisocyanates can be used individually or in the form of mixtures. Corresponding "oligomers" of diisocyanates can also be used, such as the IPDI trimer based on isocyanurate, biuret, or urethdiones. Furthermore, the use of prepolymers, particularly based on the above-mentioned isocyanates, is possible. Particularly suitable is the mixture known as "polymeric MDI" (also called "crude MDI"), consisting of MDI and more highly condensed analogues with an average functionality of 2 to 4, as well as the various isomers of TDI in pure form or as a mixture of isomers. It is also possible to use isocyanates modified by the incorporation of urethane, uretdione, isocyanurate, allophanate, and other groups, so-called modified isocyanates. Examples of particularly suitable isocyanates include:in EP 1712578, EP 1161474, WO 00 / 58383, US 2007 / 0072951 , EP 1678232 and WO 2005 / 085310, which are incorporated herein by reference.

[0090] A preferred ratio of polyisocyanate component and polyol component, expressed as an index of the formulation, ie as a stoichiometric ratio of isocyanate groups to isocyanate-reactive groups (e.g. OH groups, NH groups) multiplied by 100, is in the range from 10 to 1000, preferably 40 to 500. An index of 100 represents a molar ratio of the reactive groups of 1 to 1.

[0091] Suitable catalysts (d) which can be used for the production of polyurethanes, in particular PU foams, are known to the person skilled in the art from the prior art; for the purposes of the present invention, all compounds which are capable of catalyzing the reaction of isocyanate groups with OH, NH, or other isocyanate-reactive groups and / or the reaction of isocyanate groups with one another can be used. The conventional 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 / or metal salts, preferably those of tin, iron, bismuth, potassium and / or zinc. In particular, mixtures of several such compounds can be used as catalysts.

[0092] Foam stabilizers (e) and their use in the production of PU foams are known to those skilled in the art. The use of foam stabilizers is optional; preferably, one or more foam stabilizers are used. Surface-active compounds (surfactants) can be used as foam stabilizers. They can serve to optimize the desired cell structure and the foaming process. Within the scope of this invention, Si-containing compounds can be used in particular, which support foam production (stabilization, cell regulation, cell opening, etc.). These compounds are sufficiently known from the prior art. With particular preference, at least one foam stabilizer based on a polyether siloxane (polydialkylsiloxane-polyether copolymer) can be used. Corresponding siloxane structures that can be used within the meaning of this invention are, for example,Described in the following patents: CN 103665385, CN 103657518, CN 103055759, CN 103044687, US 2008 / 0125503, US 2015 / 0057384, EP 152087 A1, EP 1211279, EP 0867464, EP 0867465, EP 0275563. In addition to surface-active Si-containing compounds, Si-free surfactants can also be used. For example, EP2295485 A1 describes the use of lecithin, and US 3746663 describes the use of vinylpyrrolidone-based structures as foam stabilizers for the production of rigid PU foam. Further Si-free foam stabilizers are described, for example, in EP 2511328 B1, DE 102001 1007479 A1, DE 3724716 C1, EP 0734404, EP 1985642, DE 2244350 and US 5236961.

[0093] Blowing agents and their use in the production of PU foams are known to those skilled in the art. The use of blowing agents is optional; preferably, blowing agents are used. The use of one or a combination of several blowing agents (f) depends fundamentally on the type of foaming process used, the type of system, and the application of the resulting PU foam. Chemical and / or physical blowing agents, or a combination of both, can be used. Depending on the amount of blowing agent used, a foam with a high or low density is produced. For example, foams with densities of 3 kg / m 3 up to 900 kg / m 3 , preferably 5 to 350, particularly preferably 8 to 200 kg / m 3 , especially 8 to 250 kg / m 3 be manufactured.

[0094] As physical blowing agents, preferably one or more of the corresponding compounds with suitable boiling points and mixtures thereof, such as hydrocarbons with 3, 4 or 5 carbon atoms, preferably cyclo-, iso-, n-pentane, fluorocarbons (HFC), preferably HFC 245fa, HFC 134a or HFC 365mfc, chlorofluorocarbons (HCFC), preferably HCFC 141 b, hydrofluoroolefins (HFO) or hydrohaloolefins, preferably 1234ze, 1234yf, 1224yd, 1233zd(E) or 1336mzz, esters, preferably methyl formate, ketones, preferably acetone, ethers preferably dimethoxymethane, or chlorinated hydrocarbons, preferably dichloromethane or 1,2-dichloroethane.

[0095] Likewise, gaseous propellants can also preferably be used in pressure cans, whereby all suitable gases under pressure or in pressure-liquefied form are suitable, for example hydrocarbons such as butane isomers and propane isomers, dimethyl ether, nitrogen, air and other suitable gases.

[0096] As chemical blowing agents, one or more compounds can preferably be used which react with NCO groups to release gases, such as water or formic acid, or which release gases due to the temperature increase during the reaction, such as sodium bicarbonate.

[0097] As optional additives (g) it is possible to use one or more of the substances known from the prior art which are used in the production of polyurethanes, in particular PU foams, such as crosslinkers, chain extenders, stabilizers against oxidative degradation (so-called antioxidants), flame retardants, biocides, cell-refining additives, nucleating agents, other cell openers, solid fillers, antistatic additives, thickeners, dyes, pigments, color pastes, fragrances and / or emulsifiers, etc. As optional flame retardants, the composition according to the invention can contain one or more of the known flame retardants suitable for the production of PU foams, such as halogen-containing or halogen-free organic phosphorus-containing compounds, such asTriethyl phosphate (TEP), tris(1-chloro-2-propyl) phosphate (TCPP), tris(2-chloroethyl) phosphate (TCEP), dimethylmethanephosphonate (DMMP), dimethylpropanephosphonate (DMPP), ammonium polyphosphate or red phosphorus, chlorinated paraffins, nitrogen-containing compounds such as melamine, melamine cyanurate or melamine polyphosphate, or halogenated compounds such as chlorinated and / or brominated polyether and / or polyester polyols. Mixtures of different flame retardants can also be used.

[0098] Unless otherwise apparent from this description, any preferred or particularly preferred embodiment of the invention may be combined with one or more of the other preferred or particularly preferred embodiments of the invention.

[0099] The process for producing PU foams can be carried out using all known methods, e.g., by hand mixing or, preferably, using foaming machines. If the process is carried out using foaming machines, high-pressure or low-pressure machines can be used. The process for producing PU foams can be carried out both batchwise and continuously, and 1K, 1.5K, or 2K systems, as described in EP 3717538 A1, US 7776934 B2, EP 1400547 B1, or EP 2780384 B2, can be used.

[0100] One-component PU can foam is well known to those skilled in the art from the prior art. For the purposes of the present invention, the term one-component PU can foam encompasses polyurethane foams that are preferably characterized by the presence of a polyol-isocyanate prepolymer that can be propelled from a pressurized can using gases as a blowing agent, thereby foaming it.

[0101] Prepolymers particularly suitable for this purpose are obtainable, for example, by reacting polyols and (poly)isocyanate with suitable catalysts (e.g., blowing catalysts such as 2,2'-dimorpholinyl diethyl ether) or without the use of a catalyst. The final curing of these prepolymers then occurs under the influence of moisture, for example, from the environment. This type of foam is used for the assembly, bonding, and sealing of windows, door frames, pipes, penetrations, etc., as well as for filling gaps, cavities, cracks, and joints in masonry.

[0102] Spray foam is a free-flowing foam that is applied to a substrate by spraying or squirting the liquid reactants. It is typically applied using a spray foam machine, which can be a high- or low-pressure machine and combines and mixes the two components (polyol mixture and (poly)isocyanate). The foam is typically dispensed using a static mixer in the form of a spray gun. In principle, however, the raw materials or foam can also be dispensed from a larger container using gas pressure, similar to the principle used for canned foams. The foam is used for insulation and for structural purposes on walls, roofs, and floors and can be open-cell or closed-cell, depending on the application.

[0103] Packaging foam is used for packaging, protecting, and cushioning delicate goods. Typically, a low-density, open-cell foam is used to tightly enclose the goods to be protected and protect them from damage, impact, etc. For this purpose, the foam may also be injected directly into the space between the packaging and the goods.

[0104] Thermoformable rigid polyurethane foams are rigid polyurethane foams that are mechanically shaped after production, for example, through the application of heat, water (steam), and pressure. This process produces a molded part from the initially block-shaped foam, which may be trimmed. Examples include roof liner foam (also called headliner foam) and hood liner foam (foam for trunk linings and trim).

[0105] Floral foam, which is used for arranging flowers, etc., is a polyurethane foam which, due to its low density, mechanical properties and high open cell structure, is suitable for holding flowers and other objects by inserting them into the foam.

[0106] Pipe insulation foam is a polyurethane foam used to insulate pipes. It protects the pipe and its contents from heat or cold loss, as well as from mechanical stress. Particularly in pipes laid in waterways, the ocean, and the deep sea, a high degree of open-cell density is sometimes desirable for mechanical reasons.

[0107] The SiOC-linked, linear polydialkylsiloxane-polyether block copolymers with repeating (AB) units described in this invention are preferably used as surface-active additives, in particular as cell openers, in particular also in all other PU foam, in particular PU rigid foam applications in which a high degree of open cell density is desired, which, for example, has a direct positive effect on the dimensional stability of the foam.

[0108] The measurement of the open-cell or closed-cell content of a rigid polyurethane foam is trivial for the expert and can be carried out preferably according to DIN ISO 4590:2016-12 “Determination of the volume fraction of open and closed cells in rigid foams”, e.g. using a gas pycnometer.

[0109] For the purposes of this invention, "high open-cell density" is defined as an open-cell density of the PU foam, in particular rigid PU foam, of preferably > 30%, more preferably > 50%, and especially > 70% of the cells. A possible upper limit for open-cell density may be, for example, 90% of the cells, or 80% of the cells, or 100% of the cells.

[0110] The measurement of the dimensional stability of a one-component PU canister foam can preferably be carried out according to the method TM 1004:2013 of the FEICA - Association of the European Adhesive & Sealant Industry (“Determination of the Dimensional Stability of an OCF Canister Foam”, Brussels, 19.02.2013).

[0111] Experimental part:

[0112] Measurement methods:

[0113] To determine parameters or measured values, the methods described below are preferably used within the scope of the present invention. In particular, these methods were used in the examples of the present patent.

[0114] The SiH conversion of the dehydrogenative coupling is determined by butylate-catalyzed release of the residual (SiH) contained in the sample as elemental hydrogen and its quantitative determination. To determine an SiH value, a defined amount of the sample to be analyzed (between 0.3 and 10 g of sample, depending on the expected SiH value) is weighed on an analytical balance into a reaction vessel containing a magnetic stirrer bar. The reaction vessel is equipped with a dropping funnel filled with approximately 25 mL of a sodium butylate solution (5% in n-butanol). The reaction vessel is connected via a ground joint with a 3-way stopcock to a 50 mL water-filled burette, which in turn is connected via a hose to a water-filled compensation vessel. The reaction vessel stands on a magnetic stirrer plate located at approximately eye level. At the beginning of the analysis, the 3-way valve must be set so that all three ways are open.The equalizing vessel is removed from its holder and brought close to the burette. The aim is to bring the two liquid levels (burette & equalizing vessel) over each other at zero. When this is the case, the 3-way stopcock is adjusted so that only the path between the burette and the reaction vessel is open. After a waiting time of 60 seconds, the liquid levels are brought over each other again at zero to check the tightness of the apparatus. If there is a leak, the ground joints must be checked and re-greased if necessary to ensure a leak-free apparatus. Once a leak has been identified and rectified, the level adjustment at zero must be repeated. If the experimental setup is leak-tight, the magnetic stirrer is set to a low stirring speed and the butylate solution is added dropwise so that the falling water column in the burette does not break off. From time to time, the liquid surfaces are brought over each other again.If the displaced liquid volume remains stable, i.e., the volume remains unchanged when the liquid levels are placed one above the other, the achieved volume is recorded as the maximum released gas volume. Taking into account the pressure of the water vapor according to the Landolt-Börnstein equation, the SiH value can be calculated based on the weighed amount and using the general gas equation.

[0115] Within the scope of this invention, weight-average and number-average molecular weights are determined for the SiOC-linked, linear polydialkylsiloxane-polyoxyalkylene block copolymers prepared, as well as for the linear α,α-(SiH)-functional polydialkylsiloxanes used, calibrated against a polystyrene standard by gel permeation chromatography (GPC). In the following examples, the polydispersity index (PDI) is given as a further characteristic parameter for describing the molecular weight distribution. GPC was performed on a PSS SECurity 1260 (Agilent 1260) equipped with an RI detector and an SDV 1000 / 10000 Ä column combination consisting of a 0.8 cm x 5 cm guard column and two 0.8 cm x 30 cm main columns at a temperature of 30°C and a flow rate of 1 mL / min (mobile phase: THF). The sample concentration was 10 g / L and the injection volume was 20 pL.

[0116] The wet chemical analysis was carried out according to international standard methods: iodine number (IoD; DGF CV 11 a (53); acid number (Az; DGF CV 2); OH number (ASTM D 4274 C).

[0117] Description of a preferred method for controlling hydrogen evolution:

[0118] The process according to the invention is characterized in that the two reactants (a) and (b) are reacted, preferably in equimolar amounts and with controlled hydrogen evolution, until quantitative SiH conversion is achieved, with reactant (b) being initially introduced and reactant (a) being metered in. The term "controlled hydrogen evolution" specifically provides that the rate of addition of component (a) to (b) is such that the deviation of the actual conversion from the target conversion is preferably in the range from 0 to 10%, preferably from 0 to 7.5%, and particularly preferably from 0 to 5%.

[0119] A preferred method for determining hydrogen evolution is as follows:

[0120] The reaction is carried out in a 1000 ml flat-ground four-neck flask equipped with a stainless steel Sigma-Stirrer®, internal thermometer, and a reflux condenser with a gas vent tube. A standard heating element, controlled by PID fuzzy logic, serves as the heating medium. The siloxane to be dosed (component (a)) is drawn into a storage vessel placed on a tared scale using a peristaltic pump and transferred into the flat-ground flask.

[0121] The gas vent tube of the flat-ground flask leads via a transition piece with an olive into a gas-tight 4-liter two-neck flask, which is filled with boiled, gas-free water to a dead volume. The two-neck flask is also equipped with a gas inlet tube with an olive that extends just above the flask crown. The two-neck flask rests on a tared scale.

[0122] When the siloxane dosage is started, the reaction begins immediately, and the resulting gas, which causes volume expansion throughout the system, is transferred into the two-necked flask. This, in turn, forces the water content out of the flask via the inlet tube and collects it in another collecting container.

[0123] By continuously tapping the individual masses via differential weighing of the siloxane and the two-neck flask, it is possible to depict the rate at which the two reactants (a) and (b) react to form the product. For this purpose, data pairs of the masses of the siloxane feed flask and the two-neck flask are recorded. The mass of the metered siloxane can be used to calculate the theoretical gas volume occupied by the released hydrogen (a by-product) of the condensation reaction at this point in time. This allows the target conversion of the respective reaction system to be calculated over the entire reaction process. This is shown as a dashed line in Figures 1 to 5.

[0124] The actual gas volume evolved can be determined using the mass of displaced water and the water density at a given temperature. The gas volume is converted to standard conditions using the gas laws for ideal gases. This allows the actual conversion of the respective reaction system to be determined over the entire reaction process. This is shown as a solid line in Figures 1 to 5.

[0125] The quotient of the actual gas volume developed and the theoretical gas volume describes the degree of conversion of the reaction at that time.

[0126] As can be seen from the following examples according to the invention and from FIG. 6, it is particularly preferred according to the invention that the rate of siloxane dosing is selected such that the deviation of the "actual conversion" from the "target conversion" is preferably in the range from 0 to 10%, preferably from 0 to 7.5%, and particularly preferably from 0 to 5%. This specification preferably applies from a siloxane dosage amount of 10% of the total amount to be dosed and particularly preferably from 5% of the total amount to be dosed. The person skilled in the art can thus quickly set an optimal siloxane dosing rate through simple manual testing and thus achieve optimally controlled hydrogen evolution.

[0127] Example 1 (according to the invention):

[0128] In a 1000 ml flat-ground four-neck flask equipped with a stainless steel Sigma stirrer, dosing unit with peristaltic pump, internal thermometer, and reflux condenser with gas vent tube, 115.8 g of a dried polyoxyalkylenediol with a water content of <0.02% are placed. The polyoxyalkylenediol, with a weight-average molecular weight of 2,800 g / mol and an ethylene oxide / propylene oxide ratio of approximately 1:1, is combined with 198.0 g of a linear alkylbenzene with a boiling range of approximately 240 to 314°C. The mixture is heated to 105°C. Now 123.0 mg of tris(pentafluorophenyl)borane (600 ppm based on the total amount of reactants) dissolved in 20 g of the alkylbenzene described above are added. After stirring for 5 minutes, 180.0 g of a 1:1 mixture of a,co-hydrogensiloxane (average chain length N=30) and the alkylbenzene described above are added in an equimolar ratio to the polyoxyalkylenediol used.The dosing quantity and rate are adjusted using a programmable peristaltic pump so that the total amount of the mixture is divided into approximately 18 individual intervals of 10 g each. The actual dosing time of 2 minutes is immediately followed by a dosing pause of 10 minutes. This process is repeated in the same way for all 18 intervals. After adding the stoichiometric amount of siloxane, a significant increase in viscosity is observed. The end of the reaction can be clearly determined by the decreasing gas evolution. Gas volumetric SiH determination confirms complete conversion. A colorless, highly viscous product is obtained with a viscosity of 41,950 mPa s, a weight-average molecular weight of Mw 171,400 g / mol, and a PDI of 3.214.

[0129] Example 2 (according to the invention):

[0130] In a 1000 ml flat-ground four-neck flask equipped with a stainless steel Sigma stirrer, dosing unit with peristaltic pump, internal thermometer, and reflux condenser with gas vent tube, 210.9 g of a dried polyoxyalkylenediol with a water content of <0.02% are placed. The polyoxyalkylenediol, with a weight-average molecular weight of 2,800 g / mol and an ethylene oxide / propylene oxide ratio of approximately 1:1, is combined with 536.4 g of a linear alkylbenzene with a boiling range of approximately 240 to 314°C. The mixture is heated to 105°C. Now, 260.0 mg of tris(pentafluorophenyl)borane (700 ppm based on the total amount of reactants) dissolved in 20 g of the alkylbenzene described above are added. After a stirring time of 5 minutes, 160.0 g of an a,co-hydrogensiloxane (average chain length N=30) are added in an equimolar ratio to the polyoxyalkylenediol used.The dosing rate and rate are adjusted using a programmable peristaltic pump so that the total amount of hydrogen siloxane is metered in continuously over 120 minutes. After adding the stoichiometric amount of siloxane, a significant increase in viscosity is observed. The end of the reaction can be clearly determined by the decreasing gas evolution. Gas volumetric SiH determination confirms complete conversion. A colorless, highly viscous product is obtained with a viscosity of 8786 mPa s, a weight-average molecular weight of Mw 101800 g / mol, and a PDI of 2.465. Example 3 (according to the invention):

[0131] In a 1000 ml flat-ground four-neck flask equipped with a stainless steel Sigma stirrer, dosing unit with peristaltic pump, internal thermometer, and reflux condenser with gas vent tube, 135.4 g of a dried polyoxyalkylenediol with a water content of <0.02% are placed. The polyoxyalkylenediol, with a weight-average molecular weight of 2,800 g / mol and an ethylene oxide / propylene oxide ratio of approximately 1:1, is combined with 234.4 g of a linear alkylbenzene with a boiling range of approximately 240 to 314°C. The mixture is heated to a temperature of 105°C. 167.0 mg of tris(pentafluorophenyl)borane (700 ppm based on the total amount of reactants) dissolved in 20 g of the above-described alkylbenzene are then added. After a stirring time of 5 minutes, 205.4 g of a 1:1 mixture of a,co-hydrogensiloxane (average chain length N=30) and the alkylbenzene described above are added in an equimolar ratio to the polyoxyalkylenediol used.The dosing quantity and speed are adjusted using a programmable peristaltic pump so that the total amount of the mixture is divided into approximately 18 individual intervals of 11.4 g each. The actual dosing time of 2 minutes is immediately followed by a dosing pause of 15 minutes. This process is repeated in the same way for all 18 intervals. After adding the stoichiometric amount of siloxane, a significant increase in viscosity is observed. The end of the reaction can be clearly determined by the decreasing gas evolution. Gas volumetric SiH determination confirms complete conversion. A colorless, highly viscous product is obtained with a viscosity of 6197 mPa s, a weight-average molecular weight of Mw 91212 g / mol, and a PDI of 2.341.

[0132] Example 4 (according to the invention):

[0133] 160.9 g of a dried polyoxyalkylenediol with a water content of <0.02% are placed in a 1000 ml flat-ground four-neck flask equipped with a stainless steel Sigma stirrer, dosing unit with peristaltic pump, internal thermometer, and reflux condenser with gas discharge tube. The polyoxyalkylenediol, with a weight-average molecular weight of 2,800 g / mol and an ethylene oxide / propylene oxide ratio of approximately 1:1, is combined with 410.6 g of a linear alkylbenzene with a boiling range of approximately 240 to 314°C. The mixture is heated to a temperature of 105°C. 201.0 mg of tris(pentafluorophenyl)borane (700 ppm based on the total amount of reactants) dissolved in 20 g of the above-described alkylbenzene are then added. After a stirring time of 5 minutes, 160.0 g of an a,co-hydrogensiloxane (average chain length N=30) are added in an equimolar ratio to the polyoxyalkylenediol used.The dosing rate and rate are adjusted using a programmable peristaltic pump so that the total amount of hydrogen siloxane is metered in continuously over 221 minutes. After adding the stoichiometric amount of siloxane, a significant increase in viscosity is observed. The end of the reaction can be clearly determined by the decreasing gas evolution. Gas volumetric SiH determination confirms complete conversion. A colorless, highly viscous product is obtained with a viscosity of 60,210 mPa s, a weight-average molecular weight of Mw 173,600 g / mol, and a PDI of 3.095. Example 5 (not according to the invention):

[0134] In a 1000 ml flat-ground four-neck flask equipped with a stainless steel Sigma stirrer, dosing unit with peristaltic pump, internal thermometer, and reflux condenser with gas vent tube, 115.8 g of a dried polyoxyalkylenediol with a water content of <0.02% are placed. The polyoxyalkylenediol, with a weight-average molecular weight of 2,800 g / mol and an ethylene oxide / propylene oxide ratio of approximately 1:1, is combined with 198.0 g of a linear alkylbenzene with a boiling range of approximately 240 to 314°C. The mixture is heated to a temperature of 105°C. 123.0 mg of tris(pentafluorophenyl)borane (600 ppm based on the total amount of reactants) dissolved in 20 g of the above-described alkylbenzene are then added. After a stirring time of 5 minutes, 180 g of a 1:1 mixture of a,co-hydrogensiloxane (average chain length N=30) and the alkylbenzene described above are added in an equimolar ratio to the polyoxyalkylenediol used.The dosing rate and rate are adjusted using a programmable peristaltic pump so that the total amount of hydrogen siloxane is continuously added within 17 minutes. After adding the stoichiometric amount of siloxane, a significant increase in viscosity is observed. The end of the reaction can be clearly determined by the decreasing gas evolution. Gas volumetric SiH determination confirms complete conversion. A colorless, highly viscous product is obtained with a viscosity of 13,780 mPa*s, a weight-average molecular weight of Mw 145,100 g / mol, and a PDI of 2.689.

[0135] Regarding the figures FIG 1 to FIG 6:

[0136] Figures 1 to 6 illustrate examples 1 to 5 of the invention. Figures 1 to 5 each show the released hydrogen volume as a function of the added amount of hydrogen siloxane for examples 1 to 5. The experiments differ in terms of the dosage type (continuous or interval) and / or dosage rate, as previously described. The dashed line indicates the target conversion. The solid line indicates the actual conversion.

[0137] Figure 6 summarizes the influence of the reaction procedure on the deviation from the target to the actual conversion as a function of the dosed siloxane mass for examples 1 to 5.

[0138] Examples of the use of SiOC-linked, linear polydialkylsiloxane polyether block copolymers as cell openers in polyurethane formulations:

[0139] The SiOC-linked, linear polydialkylsiloxane-polyether block copolymers obtained in the aforementioned inventive (Ex. 1-4) and non-inventive (Ex. 5) examples were used as cell openers. The following raw materials were used to produce rigid polyurethane foams:

[0140] Rokopol® G 1000: Polyether polyol from Rokita

[0141] Rokopol® D 1002: Polyether polyol from Rokita

[0142] Desmophen® DE 10WF 15: Polyether polyol from Covestro

[0143] Voranol® CP 3322: Polyether polyol from Dow

[0144] PEG 600: Polyethylene glycol

[0145] Stabilizer: TEGOSTAB® foam stabilizers from Evonik Operations GmbH,

[0146] TEGOSTAB® B 84728 (one-component PU can foam)

[0147] TEGOSTAB® B 8870 (packaging foam)

[0148] TCPP: Tris(2-chloroisopropyl)phosphate from Fyrol (flame retardant)

[0149] DABCO® DMDEE, from Evonik Operations GmbH, amine-based catalyst dimethyl ether

[0150] Propane n-butane iso-butane

[0151] MDI: Desmodur® 44V20L from Covestro, diphenylmethane-4,4'-diisocyanate (MDI) with isomers and higher functional homologues.

[0152] Production of polyurethane foams:

[0153] For testing in one-component PU can foam, all components of the formulation (see Table 1) except the propellant were filled into empty aerosol cans. The cans were then sealed with the appropriate valves, and finally, the specified amount of propellant (LPG, DME) was added via compressed air burettes. The cans were then shaken manually for 1 minute and subsequently rotated in a rotary mixer for 30 minutes to achieve a homogeneous mixture and form a uniform prepolymer.

[0154] To test the pore structure and internal defects, the contents of the can are dispensed after 24 hours using a standard foam gun. A foam strand is dispensed onto paper, and the foam quality is visually assessed after curing the foam after 24 hours using a scale of 1 to 10. For this purpose, the foam is cut in half. A value of 10 represents a perfect foam with no internal defects or an extremely fine cell; a value of 1 represents a collapsed foam or extremely coarse cells.

[0155] To determine the dimensional stability of a one-component PU canister foam with regard to its susceptibility to shrinkage and expansion behavior, the dimensional stability test (DMS test) was used according to method TM 1004:2013 of the FEICA - Association of the European Adhesive & Sealant Industry ("Determination of the Dimensional Stability of an OCF Canister Foam", Brussels, February 19, 2013). For this test, two wooden panels were immersed in water for 30 seconds to allow the substrate to absorb a defined amount of water. Before applying the foam, the foam cans were shaken by hand for 1 minute and a preliminary portion of the can contents was discarded (by pressing the foam gun for approximately 3-5 seconds). Subsequently, 15 g of foam was applied between the wooden panels. The wooden panels were secured with spacers and wooden clamps so that they maintained a constant distance of 2 cm from each other.After 24 hours, the spacers and wooden clamps are removed, and the width between the two wooden panels is determined using a caliper. The width measurement is repeated after 2, 3, 7, and 14 days, and the deviation from the 2 cm starting point is calculated as a percentage and recorded. Minimal shrinkage or subsequent expansion is desirable, which correlates with a high degree of open-cell foam.

[0156] The packaging foam formulation was tested using a hand-mixing method. All components according to the formulation in Table 2, with the exception of the polyisocyanate (MDI), were weighed into a beaker and mixed with a 6 cm diameter plate stirrer for 30 seconds at 1000 rpm. The polyisocyanate (MDI) was then added, and the reaction mixture was stirred with the described stirrer for 5 seconds at 3000 rpm. The mixture was then transferred to a 27 x 27 cm box. 2The foam is applied to the base surface. The foam molding is demolded after 10 minutes. After 24 hours, the foam molding is visually assessed for shrinkage behavior. The degree of internal defects and the pore structure are also visually assessed after 24 hours using a cross-sectional area of ​​the foam on a scale of 1 to 10, with 10 representing an undisturbed foam and 1 representing an extremely severely disturbed foam.

[0157] Table 1 (Formulation for one-component PU can foam) Table 2 (Formulation for two-component packaging foam)

[0158] The results of the foaming tests in one-component PU canned foam using the examples are summarized in Table 3. Foam strands were produced as described above, and strain gauge tests were conducted. Internal defects, or pore fineness, were rated on a scale of 1-10. Dimensional stability (DMS) is expressed as % shrinkage (negative values) or expansion (positive values) relative to the original foam thickness. Measurements were taken after 1, 2, 3, 7, and 14 days.

[0159] Table 3: Results of the foaming tests in one-component PU can foam

[0160] It is clearly evident from the experiments that the cell openers according to the invention (Examples 1-4) achieve significantly improved dimensional stability compared to the non-inventive product from Example 5. No negative influence on the pore structure and internal disturbances can be observed.

[0161] The results of the foaming tests in the packaging foam with the examples are summarized in Table 4. The internal defects and pore structures were rated on a scale of 1-10, analogous to the tests in the one-component PU can foam. Table 4: Results of the foaming tests in the two-component packaging foam

[0162] From the experiments it is clearly evident that the cell opener according to the invention effectively prevents shrinkage without showing a negative influence on the pore structure and internal disturbances (e.g.

[0163] 11). In non-inventive Example 12, slight shrinkage of the foam molding was observed after 24 hours, caused by insufficient cell opening. At the same time, the pore structure and internal defects were deteriorated compared to Example 11.

Claims

Patent claims:

1. A process for the preparation of SiOC-linked, linear polydialkylsiloxane-polyoxyalkylene block copolymers having repeating (AB) units, comprising the reaction of a linear, a,co-(SiH)-functional polydialkylsiloxane (a) with a linear, a,co-(OH)-functional polyoxyalkylene (b), using one or more element compounds of main group III and / or transition group 3 as catalyst (c), optionally in the presence of a solvent (d), characterized in that the two reactants (a) and (b) are reacted preferably in equimolar amounts and with controlled evolution of hydrogen until quantitative SiH conversion.

2. Process according to claim 1, characterized in that the linear (a,co-SiH)-functional polydialkylsiloxane used has SiH values ​​between 0.25 and 3.0 mol / kg, preferably between 0.5 and 2.0 mol / kg, in particular between 0.75 and 1.5 mol / kg.

3. Process according to claim 1 or 2, characterized in that the linear a,co- (SiH)-functional polydialkylsiloxane satisfies the general formula (I): M' - Da - M' Formula (I) where M' = [HR 1 2SiOi / 2] D = [R 1 2SiO2 / 2] a = 8 - 100, preferably 10 - 60, particularly preferably 20 - 50, R 1 = independently of one another identical or different hydrocarbon radicals having 1 - 20 carbon atoms, preferably methyl, ethyl, propyl or butyl, particularly preferably methyl.

4. Process according to one of claims 1 to 3, characterized in that the linear a,co-(OH)-functional polyoxyalkylene satisfies the formula (II): HO-(CnH( 2n -m)R 2 mO-)bH Formula (II) b = 1 - 200, preferably 10 - 100, particularly preferably 25 - 60, n = 2 - 4, m = 0 or 1, R 2= independently of one another identical or different hydrocarbon radicals having 1 - 12 carbon atoms, preferably methyl, ethyl, propyl or butyl, particularly preferably methyl or ethyl.

5. Process according to one of claims 1 to 4, characterized in that the oxyalkylene units in the linear a,co-(OH)-functional polyoxyalkylene consist essentially of oxyethylene units and / or oxypropylene units, preferably mixed oxy- ethylene and oxypropylene units, in particular with an oxyethylene content of 25 to 70 wt.% and 70 to 25 wt.% oxypropylene content, based on the total content of oxyalkylene units.

6. Process according to one of claims 1 to 5, characterized in that the molar ratio of the two reactants (a) to (b) is in the range from 0.9 to 1.10, preferably 0.98 to 1.02, in particular 1 to 1.

7. Process according to one of claims 1 to 6, characterized in that it is carried out in the presence of solvent, wherein solvent is added to the reactants (a) and / or (b), wherein the total solvent content based on the total amount of reactants (a), (b) and solvent is preferably between 40 wt.% and 75 wt.% solvent, in particular between 55 wt.% and 65 wt.%.

8. Process according to one of claims 1 to 7, characterized in that the reaction of reactants (a) and (b) is carried out in such a way that reactant (b) is initially introduced and reactant (a) is metered in, wherein the metering is carried out continuously or in intervals, in particular as follows: (i) Reactant (b) is heated to reaction temperature, catalyst is added and mixed, then reactant (a) is added under controlled hydrogen evolution, (ii) Reactant (b) is heated to reaction temperature, catalyst is added and mixed, then reactant (a), diluted with solvent, is added under controlled hydrogen evolution, (iii) Reactant (b) is heated to reaction temperature, diluted with solvent and the catalyst is added and mixed, then reactant (a) is added with controlled hydrogen evolution, or (iv) Reactant (b) is heated to reaction temperature, diluted with solvent, the catalyst is added and mixed, then reactant (a), diluted with solvent, is added under controlled hydrogen evolution.

9. Process according to one of claims 1 to 8, characterized in that the reaction temperature for the preparation of the SiOC-linked, linear polydialkylsiloxane-polyoxyalkylene block copolymers with repeating (AB) units is in the range from 60°C to 140°C, in particular 100°C to 120°C.

10. A process according to any one of claims 1 to 9, characterized in that the catalyst is used in amounts of 0.01 to 0.2% by weight, preferably 0.03 to 0.10% by weight, based on the sum of the amount of reactants (a) and (b), wherein the element compounds of main group III are preferably a boron-containing and / or aluminum-containing containing catalyst and / or as element compounds of the 3rd subgroup preferably a scandium-containing, yttrium-containing, lanthanum-containing and / or lanthanide-containing catalyst.

11. Process according to one of claims 1 to 10, characterized in that, in order to control the evolution of hydrogen, the rate of addition of component (a) to (b) is such that the deviation of the actual conversion from the target conversion is from 0 to 10%, preferably from 0 to 7.5% and particularly preferably from 0 to 5%.

12. SiOC-linked, linear polydialkylsiloxane-polyether block copolymers having repeating (AB) units, prepared according to a process according to any one of claims 1 to 11.

13. Block copolymer according to claim 12, characterized in that the total siloxane block proportion (A) is between 20 and 60 wt.%, in particular 40 to 50 wt.%, and the proportion of polyoxyalkylene blocks (B) is between 80 and 40 wt.%, preferably 60 to 50 wt.%, based on the total block copolymer, wherein the block copolymer preferably has an average weight-average molecular weight Mw of at least 10,000 g / mol to 250,000 g / mol, preferably 15,000 g / mol to 225,000 g / mol, in particular 20,000 g / mol to 200,000 g / mol, determinable by GPC.

14. Use of the SiOC-linked, linear polydialkylsiloxane-polyether block copolymers having repeating (AB) units according to claim 12 or 13 as surface-active additives, in particular as cell openers, for producing polyurethane foams, preferably for producing rigid polyurethane foams, in particular for producing rigid polyurethane foams with a high degree of open cell density.

15. Polyurethane foam, preferably rigid polyurethane foam, in particular rigid polyurethane foam with high open-cell density, produced using SiOC-linked, linear polydialkylsiloxane-polyether block copolymers with repeating (AB) units according to claim 12 or 13.

16. Use of a polyurethane foam, preferably rigid polyurethane foam according to claim 15 for the production of foam moldings, spray foam, insulating foam, sealing compounds, adhesive compounds, insulating compounds, assembly compounds, and / or filling compounds.

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