Method for producing SiOC-bonded linear polydialkylsiloxane-polyether-block copolymers and their use

Abstract

1. A process for producing SiOC-bonded linear polydialkylsiloxane-polyoxyalkylene block copolymers having (AB) repeating units, comprising reacting a linear a,ω-(SiH)-functional polydialkylsiloxane (a) with a linear a,ω-(OH)-functional polyoxyalkylene (b) using a compound of one or more elements of main group III and / or minor group III as a catalyst (c), wherein the two reactants (a) and (b) are reacted preferably in equimolar amounts and under controlled hydrogen evolution until quantitative SiH conversion occurs.

Description

[Technical Field]

[0001] The present invention is in the field of silicone chemistry and polyurethane chemistry and relates to a method for preparing SiOC-bonded linear polydialkylsiloxane-polyoxyalkylene block copolymers having (AB) repeating units and their use in the production of polyurethanes (abbreviated as PU).

[0002] The principle of the process for preparing SiOC-bonded polydialkylsiloxane-polyoxyalkylene block copolymers by reacting SiH-functional polyorganosiloxanes with alcohols or OH-functional polyoxyalkylene polymers using compounds of one or more elements of main group III and / or subgroup III as catalysts is known from EP 1 460 099 B1. The preferred reaction of alcohol groups with SiH groups is described therein in an at least equimolar to up to a three-fold excess. This process was used to react linear and / or branched polyorganosiloxanes with alcohols and / or OH-functional polyoxyalkylenes.

[0003] Furthermore, EP 1935922 discloses a method for preparing SiOC-bonded linear polydimethylsiloxane-polyether block copolymers having (AB) repeating units, which are used as surfactant additives for the production of polyurethane foams. EP 1935922 describes the reaction of a linear a,ω-(SiH)-functional polydimethylsiloxane with a linear a,ω-(OH)-functional polyetherdiol using one or more compounds of elements from main group III and / or subgroup III as catalysts. This method, which can be carried out without a solvent or in the presence of a solvent, is essentially characterized in that the (SiH) functional groups of the polydimethylsiloxane are used in a molar excess of preferably 1.1 to 2.0 relative to the (OH) functional groups of the polyoxyalkylene, and the reaction is continued until the (SiH) groups are no longer detectable by gas volumetric analysis.

[0004] However, the use of an excess of polysiloxane, which is significantly more expensive than the polyetherdiol component, and the subsequent lengthy post-reaction for quantitative conversion of the excess (SiH) groups are disadvantageous from an economic point of view.

[0005] The object of the present invention was therefore to provide a simple, economically viable and stable process which allows the reproducible preparation of SiOC-linked linear polydialkylsiloxane-polyoxyalkylene block copolymers having (AB) repeating units with an improved property profile, with an advantageous focus on their use as surface-active additives for the production of polyurethane foams, in particular for the production of polyurethane rigid foams.

[0006] Surprisingly, it has been found that the use of (SiH) functional groups of linear a,ω-(SiH)-functional polydialkylsiloxanes, preferably in equimolar amounts relative to the (OH) functional groups of linear a,ω-(OH)-functional polyoxyalkylenes, combined with controlled hydrogen evolution, according to claim 1, makes it possible to provide products of qualitatively higher quality than those obtainable according to the method disclosed in EP 1 935 922, in particular products with higher molecular weights. Control of hydrogen evolution can be achieved by controlling the metering. Furthermore, the method according to the invention has been found to be significantly more stable and less prone to defects.

[0007] The subject of the present invention is a method for preparing SiOC-bonded linear polydialkylsiloxane-polyoxyalkylene block copolymers having (AB) repeating units, which comprises reacting a linear a,ω-(SiH)-functional polydialkylsiloxane (a) with a linear a,ω-(OH)-functional polyoxyalkylene (b) using a compound of one or more elements of main group III and / or subgroup III as catalyst (c), optionally in the presence of a solvent (d), wherein the two reactants (a) and (b) are reacted, preferably in equimolar amounts, while controlling the hydrogen evolution, until quantitative SiH conversion occurs.

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

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

[0010] In a particularly preferred embodiment of the present invention, the linear a,ω-(SiH)-functional polydialkylsiloxane used in the process according to the invention has an SiH value of 0.25 to 3.0 mol / kg, preferably 0.5 to 2.0 mol / kg, in particular 0.75 to 1.5 mol / kg, wherein the determination of the amount of substance of SiH units in the linear a,ω-(SiH)-functional polydialkylsiloxane is based on known methods for determining SiH values ​​with alkali catalysts.

[0011] A further subject of the present invention are SiOC-bonded linear polydialkylsiloxane-polyether block copolymers having (AB) repeating units, prepared according to the process according to the invention.

[0012] The terms "SiOC-bonded linear polydialkylsiloxane-polyether block copolymer" and "SiOC-bonded linear polydialkylsiloxane-polyoxyalkylene block copolymer" are used synonymously within the meaning of the present invention.

[0013] Another object of the present invention is the use of SiOC-linked linear polydialkylsiloxane-polyether block copolymers having (AB) repeating units, prepared according to the method of the present invention, as a surface-active additive, particularly as a cell opener, for the production of polyurethane foam materials (PU foam materials), preferably rigid polyurethane foam materials, especially rigid polyurethane foams with an open cell content. Particularly preferred rigid polyurethane foam materials are one-component PU canned foams (architectural foams, construction foams, one-component foams / OCF). Particularly preferred are polyurethane rigid foam materials in which a high open cell content is advantageous, such as open-cell spray foams, packaging foams, roof liner foams, pipe insulation foams, flower arrangement foams, and / or thermoformable rigid foams.

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

[0015] A further subject of the present invention is the use of the polyurethane foams, preferably rigid polyurethane foams, in particular rigid polyurethane foams with a high open cell content, according to the invention for the production of foam moldings, spray foams, insulation foams, sealing compounds, adhesive compounds, insulating compounds, assembly compounds and / or filling compounds. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 2 shows the evolution of the gas volume released as the reaction progresses as a function of the metered siloxane mass of Example 1 from the experimental part, in each case the target conversion and the actual conversion. [Figure 2] FIG. 2 shows the evolution of the gas volume released as the reaction progresses as a function of the metered siloxane mass of Example 2 from the experimental part, in each case the target conversion and the actual conversion. [Figure 3] FIG. 2 shows the evolution of the gas volume released as the reaction progresses as a function of the metered siloxane mass of Example 3 from the experimental part, in each case the target conversion and the actual conversion. [Figure 4] FIG. 2 shows the evolution of the gas volume released as the reaction progresses as a function of the metered siloxane mass of Example 4 from the experimental part, in each case the target and actual conversions. [Figure 5]FIG. 2 shows the evolution of the gas volume released as the reaction progresses as a function of the metered siloxane mass of Example 5 from the experimental part, in each case the target conversion and the actual conversion. [Figure 6] FIG. 1 shows the difference between the target and actual conversion in % as a function of the metered siloxane mass for Examples 1 to 5 from the experimental part.

[0017] The linear a,ω-(SiH)-functional polydialkylsiloxanes used in the process according to the invention are known per se and can be equilibrated (preferably acidic) in a known manner according to any of the methods of the prior art.

[0018] They advantageously have a weight-average molecular weight of about 650 to 7000 g / mol, preferably 1000 to 6000 g / mol, in particular about 1500 to 4500 g / mol, which corresponds to a preferred embodiment of the present invention, where the determination of the average molecular weight is based on known methods of GPC analysis.

[0019] Preferably, the general formula (I): M'-D a -M' expression (I) [In the formula, M'=[HR 1 2SiO 1 / 2 ] D=[R 1 2SiO 2 / 2 ] a=8 to 100, preferably 10 to 60, particularly preferably 20 to 50; R 1 = independently of one another, identical or different hydrocarbon radicals having 1 to 20 carbon atoms, preferably methyl, ethyl, propyl or butyl, particularly preferably methyl] A linear a,ω-(SiH)-functional polydialkylsiloxane of the formula:

[0020] The linear a,ω-(OH)-functional polyoxyalkylenes used in the process according to the invention (hereinafter also referred to for the purposes of the present invention for brevity as "polyether diols") are likewise known per se. They can be prepared according to any method of the prior art. Preferably, they have the general formula (II): HO-(C n H (2n-m) R 2 m O-) b -H formula (II) is equivalent to b=1 to 200, preferably 10 to 100, particularly preferably 25 to 60; n=2-4, m=0 or 1, R 2 = independently of one another, identical or different hydrocarbon radicals having 1 to 12 carbon atoms, preferably methyl, ethyl, propyl or butyl, particularly preferably methyl or ethyl.

[0021] Preferably, the polyether diol is an addition product of at least one alkylene oxide selected from the group consisting of ethylene oxide, propylene oxide, butylene oxide, dodecene oxide and / or tetrahydrofuran with a difunctional starter such as water, ethylene glycol or propylene glycol.

[0022] Advantageously, the polyether diol is composed of at least two monomer units, particularly preferably ethylene oxide and propylene oxide.

[0023] The polyether diol advantageously consists essentially of oxyethylene units or oxypropylene units, preferably a mixed unit of oxyethylene units and oxypropylene units having an oxyethylene ratio of about 25 to 70% by weight and an oxypropylene ratio of about 70 to 25% by weight based on the total content of oxyalkylene units.

[0024] The oxyethylene units or oxypropylene units may be arranged randomly or in blocks, and are preferably arranged in blocks.

[0025] The weight average molecular weight M of each polyether diol w is advantageously about 600 to 10,000 g / mol, preferably 1,000 to 5,000 g / mol, particularly preferably 1,500 to 3,500 g / mol, whereby the determination of the average molecular weight is based on known methods for measuring the OH number.

[0026] The molar ratio of the linear a,ω-(SiH)-functional polydialkylsiloxane to the linear a,ω-(OH)-functional polyoxyalkylene preferably used in the process according to the invention is in the equimolar range, which means that the (SiH) functional groups of the linear a,ω-(SiH)-functional polydialkylsiloxane are preferably used in equimolar amounts relative to the (OH) functional groups of the linear a,ω-(OH)-functional polyoxyalkylene.

[0027] In the context of the present invention, when an equimolar ratio or equimolar amounts of two reactants (a) and (b) is mentioned, this very particularly includes, in the sense of the present invention, a range of 0.9 to 1.10, preferably 0.98 to 1.02, of linear a,ω-(SiH)-functional polydialkylsiloxane to linear a,ω-(OH)-functional polyoxyalkylene. In particular, this ratio is very precisely equimolar, i.e., 1 to 1.

[0028] The overall proportion of siloxane blocks (A) in the SiOC-bonded linear polydialkylsiloxane-polyoxyalkylene block copolymers having (AB) repeating units is advantageously 20-60% by weight, in particular 40-50% by weight, and the proportion of polyoxyalkylene blocks (B) is advantageously 80-40% by weight, preferably 60-50%. The block copolymers have a weight-average molecular weight M of at least 10,000 g / mol to about 250,000 g / mol, advantageously 15,000 g / mol to about 225,000 g / mol, in particular 20,000 g / mol to about 200,000 g / mol. wIn this case, the determination of the average molar mass is based on known methods of GPC analysis.

[0029] Depending on the application and desired product properties, the process can be selectively carried out in the presence or absence of a solvent.

[0030] The use of solvents is particularly advantageous when SiOC-bonded copolymers of particularly high molecular weight and therefore particularly high viscosity are to be prepared.

[0031] Advantageously usable solvents are, for example, alkanes, isoalkanes, cycloalkanes and / or alkylaromatics.

[0032] Advantageously usable alkanes are, for example, n-hexane, n-heptane, n-octane, n-nonane, n-decane, n-undecane and / or n-dodecane.

[0033] Advantageously usable cycloalkanes are, for example, cyclohexane, methylcyclohexane, cycloheptane, cyclooctane, cyclononane, cyclodecane, cycloundecane, cyclododecane and / or decalin.

[0034] Advantageously usable alkylaromatics are toluene, xylene, cumene, n-propylbenzene, ethylmethylbenzene, trimethylbenzene, solvent naphtha and / or alkylbenzenes available on an industrial scale.

[0035] High-boiling solvents with boiling points >120° C., particularly preferably high-boiling alkylbenzenes, can be used with advantage.

[0036] The choice of type and amount of optional solvent will depend on the particular application and can vary over a wide range.

[0037] In the context of a preferred embodiment of the present invention, in the sense of particularly good product quality and particularly good efficiency of the process, advantageously 40% to 75% by weight, particularly preferably 55% to 65% by weight, of solvent is used, based on the sum of the amounts of reactants (a), (b) and the amount of solvent (c).

[0038] The reaction temperature for the preparation of the block copolymers according to the invention is advantageously between 60°C and 140°C, particularly preferably between 100°C and 120°C, in the context of a preferred embodiment of the invention.

[0039] Catalysts which can be used advantageously in the process according to the invention in the context of preferred embodiments of the invention are Lewis acidic element compounds of main group III, in particular boron- and / or aluminum-containing element compounds.

[0040] Among Lewis acidic compounds of subgroup 3, scandium-, yttrium-, lanthanum- and / or lanthanoid-containing Lewis acids are particularly preferred. Compounds of elements of main group III and / or subgroup 3 can be used particularly preferably as halides, alkyl compounds, fluorine-containing compounds, alicyclic compounds and / or heterocyclic compounds.

[0041] A preferred embodiment of the present invention uses as catalysts fluorinated and / or non-fluorinated organoboron compounds, in particular: [ka] [ka] [ka] [ka] In particular, tris(perfluorotriphenylborane) [1109-15-5], boron trifluoride etherate [109-63-7], borane-triphenylphosphine complex [2049-55-0], triphenylborane [960-71-4], triethylborane [97-94-9] and boron trichloride [10294-34-5], tris(pentafluorophenyl)boroxine (9CI) [223440-98-0], 4,4,5,5-tetramethyl-2-(pentafluorophenyl)-1,3,2-dioxaborolane (9CI) [325142- 81-2], 2-(pentafluorophenyl)-1,3,2-dioxaborolane (9CI) [336880-93-4], bis(pentafluorophenyl)cyclohexylborane [245043-30-5], di-2,4-cyclopentadien-1-yl(pentafluorophenyl)borane (9CI) [336881-03-9], (hexahydro-3a(1H)-pentalenyl)bis(pentafluorophenyl)borane (9CI) [336880-98-9], 1,3-[2-[bis(pentafluorophenyl)boryl]ethyl]tetramethyl Disiloxane [336880-99-0], 2,4,6-tris(pentafluorophenyl)borazine (7CI, 8CI, 9CI) [1110-39-0], 1,2-dihydro-2-(pentafluorophenyl)-1,2-azaborine (9CI) [336880-94-5], 2-(pentafluorophenyl)-1,3,2-benzodioxaborole (9CI) [336880-96-7], tris(4-trifluoromethoxyphenyl)borane [336880-95-6], tris(3-trifluoromethylphenyl)borane [24455-0 0-3], 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, and mixtures of the aforementioned catalysts can preferably be used.

[0042] A further preferred embodiment of the present invention is to use as catalyst fluorinated and / or non-fluorinated organoaluminum compounds, in particular: AlCl3 [7446-70-0], aluminum acetylacetonate [13963-57-0], AIF3 [7784-18-1], aluminum trifluoromethanesulfonate [74974-61-1], diisobutylaluminum chloride [1779-25-5], diisobutylaluminum hydride [1191-15-7] and / or triethylaluminum [97-93-8] and mixtures thereof It is contemplated to use a material selected from:

[0043] A further preferred embodiment of the present invention is the use of fluorinated and / or non-fluorinated organoscandium compounds as catalysts, in particular: 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 It is contemplated to use a material selected from:

[0044] A further preferred embodiment of the present invention is to use as catalyst fluorinated and / or non-fluorinated organic yttrium compounds, in particular: 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 It is contemplated to use a material selected from:

[0045] A further preferred embodiment of the present invention is to use as catalyst fluorinated and / or non-fluorinated organolanthanum compounds, in particular: 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 It is contemplated to use a material selected from:

[0046] A further preferred embodiment of the present invention is to use fluorinated and / or non-fluorinated organolanthanoid compounds as catalysts, in particular the following: 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(III) fluoride [13765-25-8], europium(II) chloride [13769-20-5], praseodymium(III) hexafluoroacetylacetonate [47814-20-0], praseodymium(III) fluoride [13709-4 6-1], praseodymium(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 It is contemplated to use a material selected from:

[0047] The catalyst is advantageously used in an amount of from about 0.01 to about 0.2% by weight, in particular from 0.03 to 0.10% by weight, based on the sum of the amounts of reactants (a) and (b).

[0048] The catalyst can be used as a homogeneous or heterogeneous catalyst. In this case, the catalyst(s) can be added in a dissolved or suspended state. Advantageously, the catalyst can be added in a suspended or dissolved state in a small amount of solvent or polyether diol, and particularly preferably, it can be added in a dissolved state in a solvent.

[0049] In a preferred embodiment of the process according to the invention, the polyether diol is first charged and dried in a vacuum at elevated temperature, optionally in the presence of a solvent, to prevent the potential side reaction of Si-H to Si-OH in the presence of water. This can be done, for example, by vacuum distillation. The dehydrocoupling can be promoted by providing a weakly acidic medium. To provide a weakly acidic medium for the converted alcohol, diammonium phosphate (DAP; 100-500 ppm) can be added before, during, or after the distillation.

[0050] In a preferred embodiment of the process according to the invention, the preferably dried polyether diol (reactant (b)) is heated to the reaction temperature, the catalyst is added and thoroughly mixed, and then the linear a,ω-(SiH)-functional polydialkylsiloxane (reactant (a)) is metered in while controlling the hydrogen evolution.

[0051] In a preferred embodiment of the process according to the invention, the preferably dried polyether diol (reactant (b)) is heated to the reaction temperature, the catalyst is added and thoroughly mixed, and then the solvent-diluted siloxane (reactant (a)) is metered in while controlling the hydrogen evolution.

[0052] In a preferred embodiment of the process according to the invention, the preferably dried polyether diol (reactant (b)) is heated to the reaction temperature, diluted with a solvent, the catalyst is added and thoroughly mixed, and then the siloxane (reactant (a)) is metered in while controlling the hydrogen evolution.

[0053] In a preferred embodiment of the process according to the invention, the preferably dried polyether diol (reactant (b)) is heated to the reaction temperature, diluted with a solvent, the catalyst is added and thoroughly mixed, and then the solvent-diluted siloxane (reactant (a)) is metered in while controlling the hydrogen evolution.

[0054] For these four previously mentioned preferred embodiments, the following applies in each case: the metering is preferably carried out continuously, which allows a controlled reaction to proceed, which is recognizable by the corresponding continuous gas release. After gas release is complete, the reaction is finished, which can also be confirmed by sampling and external SiH value measurement.

[0055] In another preferred embodiment, the addition of pure siloxane or siloxane diluted with a solvent (reactant (a)) can also be carried out in each case at intervals rather than continuously as in the four embodiments described above. In this case, the siloxane (reactant (a)) is metered in at intervals. After each metering interval, the metering is paused, preferably until the absence of hydrogen generation indicates quantitative SiH conversion of the previously metered portion. The next interval is then added. Advantageously, the metered amount and time per interval are kept constant, but those skilled in the art can adapt this to specific applications. For example, a larger amount of siloxane can be added per interval at the beginning of the synthesis and a smaller amount towards the end, or vice versa.

[0056] During metering, it is always very advantageous to ensure efficient thorough mixing.

[0057] According to the present invention, the reaction of reactants (a) and (b) is carried out until quantitative SiH conversion is achieved while controlling hydrogen generation. In the context of the present invention, this is understood to mean that the difference between the actual conversion and the target conversion is as small as possible, preferably in the range of 0 to 10%, preferably 0 to 7.5%, and particularly preferably 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 each point in time. The term actual conversion is understood to mean the amount of hydrogen actually released at each point in time. This control of hydrogen generation can be achieved by controlling the metering of component (a) to component (b). For example, if the difference between the target conversion and the actual conversion is too large, the addition rate of component (a) can be reduced. A preferred method for controlling hydrogen generation is described in detail in the Examples section.

[0058] The SiOC-bonded linear polydialkylsiloxane-polyoxyalkylene block copolymers having (AB) repeating units produced according to the process of the invention can be particularly advantageously used as surface-active additives, in particular cell openers, for the production of polyurethanes, preferably polyurethane foam materials, in particular polyurethane rigid foam materials; in this case, particular preference is given to one-component PU canned foams (architectural foams, construction foams, one-component foams / OCF) and / or other polyurethane rigid foams in which a high open cell content is advantageous (e.g., open-cell spray foams, packaging foams, roof liner foams, pipe insulation foams, flower arrangement foams, thermoformable rigid foams, etc.). These uses are therefore also the subject of the present invention.

[0059] In the preferred applications mentioned above, it is advantageous for the finished PU foam, preferably a PU rigid foam, to exhibit slight changes in geometric dimensions during and especially after the curing process. This desired dimensional stability, i.e., slight shrinkage or slight post-expansion, can be achieved advantageously by a high open cell content of the foam. At the same time, it is desirable that the PU foam does not have serious foaming defects in the sense of cavities due to this open cell content: the cells of the foam are preferably still fine and do not have any coarse portions.

[0060] Therefore, in the production of such PU foams, it may be advantageous in some cases to use polyol-isocyanate prepolymers, in particular to add a cell opener in addition to the foam stabilizers usually present (usually polyether siloxanes), and the SiOC-bonded linear polydialkylsiloxane-polyether block copolymers according to the present invention have proven particularly effective for this purpose.

[0061] The SiOC-bonded linear polydialkylsiloxane-polyether block copolymers having (AB) repeating units obtainable according to the process of the invention can thus be used particularly advantageously as cell openers in the production of polyurethane foams, in particular rigid polyurethane foams.

[0062] The term "cell opener" is known per se to those skilled in the art in the production of PU foams. Cell opener is understood to mean a substance suitable for or capable of increasing the open cell content during the production of polyurethane foams, preferably rigid polyurethane foams, that would otherwise be predominantly closed (i.e., in the case of rigid polyurethane foams, typically have less than 30%, preferably less than 20%, and particularly preferably less than 10% open cells, based on the total number of cells). The use of SiOC-bonded linear polydialkylsiloxane-polyether block copolymers with (AB) repeating units, obtainable according to the process of the invention, as cell openers in accordance with the present invention allows the resulting polyurethane foams, in particular rigid polyurethane foams, to have a high open cell content. The term "high open cell content" is defined below.

[0063] The use concentration of the SiOC-bonded linear polydialkylsiloxane-polyoxyalkylene block copolymers having (AB) repeating units according to the invention as surface-active additives, in particular as cell openers, in the polyurethane foams to be produced, preferably rigid polyurethane foams, is advantageously 0.01% to 10% by weight, preferably 0.05% to 7% by weight, particularly preferably 0.1% to 5% by weight, in each case based on the total polyurethane foam formulation.

[0064] The term polyurethane foam is known per se to those skilled in the art (see, for example, Adam et al., "Polyurethanes", Ullmann's Encyclopedia of Industrial Chemistry - Paragraph 7", 2012, Wiley VCH-Verlag, Weinheim).

[0065] A preferred composition according to the invention of a PU foam, advantageously a polyurethane rigid foam, comprises the following constituents: a) SiOC-bonded linear polydialkylsiloxane-polyoxyalkylene block copolymers according to the present invention having (AB) repeating units b) Polyol component c) (Poly)isocyanate component d) Catalyst e) Foam stabilizers as needed f) Foaming agent g) further additives as required, preferably fillers, liquid or solid flame retardants, dispersants, etc. Contains:

[0066] In this case, the SiOC-bonded linear polydialkylsiloxane-polyoxyalkylene block copolymers according to the invention having (AB) repeating units are used as surface-active additives, preferably as cell openers.

[0067] The terms polyurethane and polyurethane foam are well-established terms of art and have long been known to those skilled in the art.

[0068] Polyurethane (PU) is understood in the context of the present invention to mean in particular the product obtained by reaction of a polyisocyanate component with a polyol component.

[0069] In addition to polyurethanes, further functional groups may also be formed here, such as uretdione, carbodiimide, isocyanurate, allophanate, biuret, urea and / or uretonimine groups, etc. PU is therefore understood within the meaning of the present invention to mean not only polyurethanes, but also polyisocyanurates, polyureas and polyisocyanate reaction products containing uretdione, carbodiimide, allophanate, biuret and / or uretonimine groups.

[0070] Accordingly, polyurethane foams (PU foams) are understood in the context of the present invention to mean foams obtained as the reaction product of a polyisocyanate component with a polyol component, where, in addition to the polyurethane from which the name is derived, further functional groups such as, for example, allophanate, biuret, urea, carbodiimide, uretdione, isocyanurate or uretonimine may also be formed.

[0071] PU rigid foam (polyurethane rigid foam material) is an established technical term. The known fundamental difference between flexible and rigid foams is that flexible foams exhibit elastic behavior, resulting in reversible deformation, while rigid foams are permanently deformed. More information on polyurethane rigid foam materials can also be found in "Kunststoffhandbuch, Band 7, Polyurethane", Carl Hanser Verlag, 3. Auflage 1993, Kapitel 6. The terms foam and "foam material" are treated as synonyms within the meaning of the present invention. In this case, the same applies to derived terms such as rigid foam or rigid foam material.

[0072] Particularly preferred PU foams within the meaning of the present invention are polyurethane rigid foams, in particular one-component can foams, open-cell spray foams, packaging foams, roof liner foams, pipe insulation foams, flower arranging foams, thermoformable rigid foams and / or further polyurethane rigid foams in which a high open-cell content is particularly advantageous.

[0073] The polyol component (b) can be one or more organic compounds having OH groups, SH groups, NH groups and / or NH2 groups and a functionality of 1.8 to 8. In this case, the polyol component contains at least one compound having at least two isocyanate-reactive groups selected from OH groups, SH groups, NH groups and / or NH2 groups, particularly OH groups.

[0074] A functionality of, for example, 1.8 can be achieved by mixing at least one compound having a higher functionality, for example, 2 or greater, with at least one compound having a functionality of, for example, 1. This can occur in particular when a polyisocyanate component (c) having a functionality of 2 or greater or an additional crosslinker is used as an optional additive.

[0075] The corresponding compounds typically used in the production of PU foams are known to those skilled in the art and are described, for example, in "Kunststoffhandbuch, Band 7, Polyurethane", Carl Hanser Verlag, 3. Auflage 1993, Kapitel 3.1. Compounds having an OH number in the range of 10 to 1200 mg KOH / g are typically used.

[0076] Particularly preferred compounds are all polyether polyols and polyester polyols which are customarily used in the production of polyurethane systems, in particular polyurethane foam materials.

[0077] Additionally, polyether polycarbonate polyols, natural oil-based polyols (NOPs; as described in WO 2005 / 033167, US 2006 / 0293400, WO 2006 / 094227, WO 2004 / 096882, US 2002 / 0103091, WO 2006 / 116456, EP 1 678 232), filler polyols, prepolymer-based polyols and / or recycled polyols may be used.

[0078] Recycled polyols are, for example, polyols obtained from the chemical recycling of polyurethanes by solvolysis, such as glycolysis, hydrolysis, acidolysis or aminolysis, etc. The use of recycled polyols constitutes a particularly preferred embodiment of the present invention.

[0079] A preferred embodiment of the present invention is presented when the polyol component contains a polyol-isocyanate-prepolymer.

[0080] As the isocyanate or polyisocyanate component (c), one or more polyisocyanates having two or more isocyanate groups can generally be used. Suitable polyisocyanates within the meaning of the present invention are all organic isocyanates having two or more isocyanate groups, in particular the aliphatic, cycloaliphatic, arylaliphatic and preferably aromatic polyisocyanates known per se.

[0081] Mention may be made here by way of example of alkylene diisocyanates having 4 to 12 carbon atoms in the alkylene group, such as 1,12-dodecane diisocyanate, 2-ethyltetramethylene-1,4-diisocyanate, 2-methylpentamethylene-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'-methylenedicyclohexane Examples of suitable diisocyanates include silyl diisocyanate (H12MDI), isophorone diisocyanate (IPDI), 2,4- and 2,6-methylcyclohexyl diisocyanate and the corresponding isomer mixtures, and preferably aromatic diisocyanates 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-polyisocyanate (PMDI, "polymeric MDI"). The organic polyisocyanates can be used alone or in the form of mixtures. Similarly, the corresponding "oligomers" of diisocyanates, such as IPDI trimers based on isocyanurates, biurets, or uretdione, can also be used. Furthermore, prepolymers based on the isocyanates specifically mentioned above can also be used. Particularly suitable are mixtures of MDI and higher condensed analogues with an average functionality of 2 to 4, known as "polymeric MDI" (also called "crude MDI" or "raw MDI"), as well as various isomers of TDI in pure form or as isomer mixtures. It is also possible to use isocyanates modified by incorporating urethane, uretdione, isocyanurate, allophanate and other groups, so-called modified isocyanates.Examples of particularly suitable isocyanates are detailed, for example, in EP 1 712 578 A1, EP 1 161 474 A1, WO 00 / 58383 A1, US 2007 / 0072951 A1, EP 1 678 232 A1 and WO 2005 / 085310 A1, which are hereby incorporated by reference in their entirety.

[0082] The preferred ratio of polyisocyanate component to polyol component is expressed as a formulation index, i.e., the stoichiometric ratio of isocyanate groups to isocyanate-reactive groups (e.g., OH groups, NH groups) multiplied by 100, and ranges from 10 to 1000, preferably 40 to 500. An index of 100 represents a 1:1 molar ratio of reactive groups.

[0083] Suitable catalysts (d) for the production of polyurethanes, especially PU foams, are known to those skilled in the art; within the meaning of the present invention, any compound capable of catalyzing the reaction of isocyanate groups with OH groups, NH groups, or other isocyanate-reactive groups, and / or with each other, can be used. Conventional catalysts known from the prior art can be used here, including, for example, amines (cyclic, acyclic; monoamines, diamines, oligomers containing 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.

[0084] Foam stabilizers (e) and their use in the production of PU foams are known to those skilled in the art. The use of a foam stabilizer is optional, although it is advantageous to use one or more foam stabilizers. In particular, surface-active compounds (surfactants) can be used as foam stabilizers. They help to achieve the desired cell structure and optimize the foaming process. In particular, in the context of the present invention, Si-containing compounds can be used that support foam production (stabilization, cell regulation, cell opening, etc.). These compounds are well known in the prior art. Particularly preferably, at least one foam stabilizer based on polyethersiloxane (polydialkylsiloxane-polyether copolymer) can be used. Corresponding siloxane structures that can be used within the meaning of the present invention are described, for example, in the following patent documents: CN 103665385, CN 103657518, CN 103055759, CN 103044687, US Patent Publication No. 2008 / 0125503, US Patent Publication No. 2015 / 0057384, EP 152087, 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, EP-A-2295485 describes the use of lecithin, and US-A-3746663 describes the use of vinylpyrrolidone-based structures as foam stabilizers for the production of PU rigid foams. Further Si-free foam stabilizers are described, for example, in EP-A-2511328, DE-A-1020011007479, DE-A-3724716, EP-A-0734404, EP-A-1985642, DE-A-2244350 and US-A-5236961.

[0085] Blowing agents and their use in the production of PU foams are known to those skilled in the art. The use of a blowing agent is optional, but advantageously a blowing agent is used. The use of one or a combination of several blowing agents (f) depends, in principle, on the type of foaming process used, the type of system, and the intended use of the resulting PU foam. Chemical and / or physical blowing agents, as well as combinations of both, can be used. Depending on the amount of blowing agent used, high- or low-density foams are produced. For densities of 3 kg / m3 and above, the use of a blowing agent of 3 kg / m3 is preferred. 3 ~900kg / m 3 , preferably 5 kg / m 3 ~350kg / m 3 , particularly preferably 8 kg / m 3 ~200kg / m 3 , especially 8 kg / m 3 ~250kg / m 3 The foam can be produced.

[0086] As physical blowing agents, it is advantageous to use one or more of the corresponding compounds having an appropriate boiling point and mixtures thereof, such as hydrocarbons having 3, 4 or 5 carbon atoms, preferably cyclopentane, isopentane, n-pentane, hydrofluorocarbons (HFCs), preferably HFC 245fa, HFC 134a or HFC 365mfc, hydrochlorofluorocarbons (HCFCs), preferably HCFC 141b, hydrofluoroolefins (HFOs) 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.

[0087] Likewise, gaseous blowing agents can also be used advantageously in pressurized cans, with any gas suitable for the purpose under pressure or in pressurized liquefied form coming into consideration, such as hydrocarbons such as butane isomers and propane isomers, dimethyl ether, nitrogen, air and further suitable gases.

[0088] As chemical blowing agents, it is possible to use advantageously one or more compounds which react with NCO groups to release a gas, such as, for example, water or formic acid, or one or more compounds which release a gas upon increasing the temperature during the reaction, such as, for example, sodium bicarbonate.

[0089] As optional additives (g) one or more of the substances known according to the prior art, which are used in the production of polyurethanes, in particular PU foams, can be used, such as crosslinkers, chain extenders, stabilizers against oxidative degradation (so-called antioxidants), flame retardants, biocides, cell refining additives, nucleating agents, further cell openers, solid fillers, antistatic agents, thickeners, dyes, pigments, color pastes, fragrances and / or emulsifiers, etc.

[0090] As an optional flame retardant, the composition according to the invention may 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 as triethyl phosphate (TEP), tris(1-chloro-2-propyl)phosphate (TCPP), tris(2-chloroethyl)phosphate (TCEP), dimethylmethane phosphate (DMMP), dimethylpropane phosphate (DMPP), ammonium polyphosphate or red phosphorus, chloroparaffins, 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 may also be used.

[0091] Unless the contrary is clear from this description, any preferred or particularly preferred embodiment of the present invention may be combined with one or more of the other preferred or particularly preferred embodiments of the present invention.

[0092] The process for producing PU foam can be carried out according to any known method, for example, by hand mixing or preferably by means of a foaming machine. When the process is carried out using a foaming machine, a high-pressure or low-pressure machine can be used. The process for producing PU foam can be carried out discontinuously or continuously, for example, using a 1K, 1.5K or 2K system as described in EP 3717538, U.S. Pat. No. 7776934, EP 1400547 or EP 2780384.

[0093] One-component PU canned foams are well known to those skilled in the art from the prior art. The term one-component PU canned foams, within the meaning of the present invention, advantageously includes polyurethane foams characterized by the presence of a polyol-isocyanate prepolymer that can be injected from a pressurized can with a gas as a blowing agent and thereby foamed.

[0094] Prepolymers suitable for this purpose are obtained, for example, by reacting polyols with (poly)isocyanates with one another, with or without a suitable catalyst (e.g., a blowing catalyst such as 2,2'-dimorpholinyl diethyl ether). The final curing of these prepolymers then takes place, for example, under the action of moisture from the environment. The areas of use for this foam type are the assembly, bonding and sealing of windows, door frames, pipes, bushings, etc., as well as the filling of gaps, cavities, cracks and joints in brickwork.

[0095] Spray foams are free-rising foams that are applied to substrates by spraying or spraying the liquid reactive components. The process is generally carried out using a spray foam machine, which may be configured as a high-pressure or low-pressure machine, in which the two components (polyol mixture and (poly)isocyanate) are combined and mixed. The foam is usually discharged using a static mixer in the form of a spray gun or gunner. However, in principle, the material or foam can be discharged by gas pressure from a larger container, similar to the principle of canned foam. Foams are used for insulating and structural purposes in walls, roofs, and floors and can be open-cell or closed-cell, depending on the application.

[0096] Packaging foams are used to help wrap, protect, and cushion delicate goods. They are typically low-density, open-cell foams designed to tightly encase the goods being protected and protect them from damage, impacts, etc. To this end, the foam is sometimes foamed directly into the space between the package and the goods.

[0097] Thermoformable rigid polyurethane foams are polyurethane rigid foams that are mechanically deformed after production, for example, by heat, water (steam), and pressure. Molded parts are produced from blocks of foam that are initially cut into pieces. Examples include roof liner foam (also called headliner foam) and hood liner foam (tailgate and lining foam).

[0098] Floral foams, used for example in flower arranging, are polyurethane foams whose low density, mechanical properties, and high open cell content make them suitable for holding flowers and other objects by inserting them into the foam.

[0099] Pipe insulation foams are polyurethane foams used to insulate pipes. They protect the pipe and its contents from heat and cooling losses, and from mechanical influences. In particular, in the field of underwater, submarine, and deep-sea pipes, a high open cell content is sometimes desirable for mechanical reasons.

[0100] The SiOC-linked linear polydialkylsiloxane-polyether block copolymers having (AB) repeating units described in the present invention can preferably be used as surface-active additives, in particular as cell openers, in particular in all other broad PU foam applications, especially in PU rigid foam applications, where a high open cell content is desirable and has a direct positive effect, for example, on the dimensional stability of the foam.

[0101] Determining the open or closed cell content of polyurethane rigid foams is straightforward for those skilled in the art and can advantageously be carried out in accordance with DIN ISO 4590:2016-12 "Determination of the volume fraction of open and closed cells in rigid-cell plastics" (Determination of the volume fraction of open and closed cells in rigid-cell plastics), for example using a gas pycnometer.

[0102] A "high open cell content" in the sense of the present invention is understood to mean that the open cell content of the PU foam, in particular the PU rigid foam, is advantageously ≧30%, more preferably ≧50%, in particular ≧70% of the cells. A possible upper limit for the open cell content may be, for example, 90% of the cells, or, for example, 80% of the cells, or, for example, 100% of the cells.

[0103] The measurement of the dimensional stability of one-component PU canned foams can advantageously be carried out according to FEICA (European Adhesives and Sealants Industry Association) method TM 1004:2013 ("Determination of the dimensional stability of OCF canister foams", Bruessel, 19.02.2013).

[0104] Experimental section: Measurement method: To determine the parameters or measurements, in the context of the present invention, the methods described below are advantageously used, in particular those methods used in the examples of the present intellectual property.

[0105] The SiH conversion rate of the dehydrogenative coupling is determined by quantitatively determining the residual (SiH) in the sample by releasing it as hydrogen atoms using a butoxide catalyst. To determine the SiH value, a specified amount of the sample to be analyzed (0.3–10 g, depending on the expected SiH value) is weighed into a reaction vessel containing a magnetic stir bar on an analytical balance. The reaction vessel is equipped with a dropping funnel containing approximately 25 mL of sodium butoxide solution (5% in n-butanol). The reaction vessel is connected to a burette filled with 50 mL of water via a ground joint (Schliff) with a three-way stopcock. This burette is equipped with a balancing vessel filled with water via a hose. The reaction vessel is placed on a magnetic stir plate at eye level. The three-way stopcock is set so that all three paths are open at the start of the analysis. The balancing vessel is removed from its holder and brought close to the burette. The goal is to align the two liquid levels (burette and balancing vessel) to zero. Once this is achieved, the three-way stopcock is set so that only the path between the burette and the reaction vessel is open. After a 60-second wait, the liquid level is again adjusted to zero to check the tightness of the apparatus. If a leak is found, inspect the joint and, if necessary, re-grease it to create a sealed apparatus. If a leak is found and repaired, the zero level adjustment must be performed again. If the experimental apparatus is leak-free, set the magnetic stirrer to a low stirring speed and add the butoxide solution dropwise to ensure a steady flow of water in the burette. While doing this, occasionally overlap the liquid surface. If the volume of the displaced liquid remains stable, i.e., the volume does not change when the liquid surface is overlapped, the resulting volume is recorded as the maximum volume of gas released. Taking into account the Landolt-Bernstein pressure of water vapor, the SiH value can be calculated using the weighed amount and the general gas equation of state.

[0106] In the context of the present invention, the weight-average and number-average molecular weights of the prepared SiOC-bonded linear polydialkylsiloxane-polyoxyalkylene block copolymers and the used linear a,ω-(SiH)-functional polydialkylsiloxanes are determined by gel permeation chromatography (GPC) with calibration to polystyrene standards. In the following examples, the polydispersity index (PDI) is reported as an additional characteristic parameter to describe the molecular weight distribution. GPC was performed at 30°C and a flow rate of 1 mL / min (mobile phase: THF) using a PSS SECurity 1260 (Agilent 1260) equipped with an RI detector and an SDV 1000 / 10000 Å column combination consisting of a 0.8 cm × 5 cm precolumn and two 0.8 cm × 30 cm main columns. The sample concentration was 10 g / L, and the injection volume was 20 μL.

[0107] Wet chemical analyses were performed according to international standard methods: iodine number (IV; DGF CV 11 a (53); acid number (AN; DGF CV 2); OH number (ASTM D 4274 C).

[0108] Description of the preferred method for controlling hydrogen generation: The process according to the invention is characterized in that the two reactants (a) and (b) are reacted, preferably in equimolar amounts, and under controlled hydrogen evolution, until quantitative SiH conversion occurs, in particular by initially charging reactant (b) and metering in reactant (a). The term "controlled hydrogen evolution" contemplates that the rate of addition of component (a) to component (b) is such that the difference between the target and actual conversion is preferably in the range of 0-10%, preferably 0-7.5%, particularly preferably 0-5%.

[0109] A preferred method for determining hydrogen evolution is as follows: The reaction is carried out in a 1000 ml four-necked ground glass flask (Planschliff-Vierhalskolben) equipped with a stainless steel Sigma stirrer, an internal thermometer, and a reflux condenser with a gas outlet hose. A standard heating mantle controlled by PID fuzzy logic serves as the heating medium to set the target temperature. The siloxane to be dispensed (= component (a)) is pumped by a peristaltic pump through a storage container placed on a tared scale and transferred to the ground glass flask.

[0110] The gas outlet hose of the ground-glass flask is connected via an olive-equipped transition piece to a hermetically sealed 4-liter two-neck flask filled with boiling, gas-free water to eliminate dead volume. The flask is fitted with a gas inlet tube with an olive-equipped end that extends to just above the flask base. The flask is placed on a tared scale.

[0111] As soon as the siloxane metering begins, the reaction begins, causing a volume expansion of the entire system, transferring the product gases into the two-neck flask, which in turn forces water out of the flask through the inlet tube and into a separate collection vessel.

[0112] The rate at which the reaction between the two reactants (a) and (b) occurs to form the product can be displayed by continuously acquiring the individual masses via differential weighing of the siloxane and the two-neck flask. To achieve this, the data pair of the masses of the siloxane reservoir flask and the two-neck flask is plotted. The mass of the siloxane dispensed allows the theoretical gas volume occupied by the hydrogen (by-product) released in the condensation reaction at this point to be calculated. In this way, the target conversion rate for each reaction system can be calculated over the entire reaction time course, as shown by the dashed lines in Figures 1-5.

[0113] The actual gas volume evolved can be determined using the mass of water displaced and the density of water at a given temperature. The gas volume is then converted to standard conditions using the ideal gas law. In this way, the actual conversion rate for each reaction system can be determined over the entire reaction time course. This is shown by the solid lines in Figures 1-5.

[0114] The quotient of the actual gas volume evolved and the theoretical gas volume represents the degree of conversion of the reaction at this point.

[0115] As can be seen from the following examples and Figure 6, according to the present invention, it is highly preferred that the siloxane metering rate be selected so that the difference between the "target conversion rate" and the "actual conversion rate" is preferably in the range of 0 to 10%, preferably 0 to 7.5%, and particularly preferably 0 to 5%. Advantageously, this rule applies from a siloxane metering amount of 10% of the total amount to be metered, particularly preferably from a siloxane metering amount of 5% of the total amount to be metered. In this way, those skilled in the art can quickly determine the optimal siloxane metering rate by simple manual experimentation, and thus achieve optimal control of hydrogen generation.

[0116] Example 1 (according to the present invention): A 1000 ml ground-glass four-neck flask equipped with a stainless steel Sigma stirrer, a peristaltic pump metering unit, an internal thermometer, and a reflux condenser with a gas outlet hose is initially charged with 115.8 g of dry polyoxyalkylene diol with a water content of <0.02%. The polyoxyalkylene diol 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 linear alkylbenzene with a boiling point range of approximately 240-314 °C. The mixture is heated to a temperature of 105 °C. Next, 123.0 mg of tris(pentafluorophenyl)borane (600 ppm based on the total amount of reactants) dissolved in 20 g of the above alkylbenzene is added. After stirring for 5 minutes, 180 g of a 1:1 mixture of α,ω-hydrogen siloxane (average chain length N=30) and the above alkylbenzene are metered in at an equimolar ratio relative to the polyoxyalkylene diol used. The metering amount and metering rate are set by a program-controlled peristaltic pump so that the total mixture is divided into approximately 18 individual sections of 10 g each. A 2-minute actual metering period is immediately followed by a 10-minute metering pause. This procedure is repeated in the same way for all 18 sections. After the addition of the stoichiometric amount of siloxane, a clear viscosity increase is observed. The end of the reaction can be clearly determined by the weakening of gas evolution. SiH measurement by the gas volume method confirms complete conversion. A viscosity of 41950 mPa·s and a weight-average molecular weight M of 171400 g / mol are obtained. w A colorless, highly viscous product is obtained having a PDI of 3.214.

[0117] Implementation 2 (according to the present invention): A 1000 ml ground-glass four-neck flask equipped with a stainless steel Sigma stirrer, a peristaltic pump metering unit, an internal thermometer, and a reflux condenser with a gas outlet hose is initially charged with 210.9 g of dry polyoxyalkylene diol with a water content of <0.02%. The polyoxyalkylene diol 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 linear alkylbenzene with a boiling point range of approximately 240-314 °C. The mixture is heated to a temperature of 105 °C. Next, 260.0 mg of tris(pentafluorophenyl)borane (700 ppm based on the total amount of reactants) dissolved in 20 g of the alkylbenzene is added. After stirring for 5 minutes, 160.0 g of α,ω-hydrogen siloxane (average chain length N = 30) is metered in at an equimolar ratio relative to the polyoxyalkylene diol used. The metering amount and metering rate are set by a program-controlled peristaltic pump so that the total amount of hydrogen siloxane is metered continuously within 120 minutes. After the addition of the stoichiometric amount of siloxane, a clear increase in viscosity is observed. The end of the reaction is clearly indicated by the weakening of gas evolution. SiH determination by the gas volume method confirms complete conversion. A viscosity of 8786 mPa·s and a weight-average molecular weight M of 101800 g / mol are obtained. w A colorless, highly viscous product is obtained having a PDI of 2.465.

[0118] Example 3 (according to the invention): A 1000 ml ground-glass four-neck flask equipped with a stainless steel Sigma stirrer, a peristaltic pump metering unit, an internal thermometer, and a reflux condenser with a gas outlet hose is initially charged with 135.4 g of dry polyoxyalkylene diol with a water content of <0.02%. The polyoxyalkylene diol 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 linear alkylbenzene with a boiling point range of approximately 240-314 °C. The mixture is heated to a temperature of 105 °C. Next, 167.0 mg of tris(pentafluorophenyl)borane (700 ppm based on the total amount of reactants) dissolved in 20 g of the above alkylbenzene is added. After 5 minutes of stirring, 205.4 g of a 1:1 mixture of α,ω-hydrogen siloxane (average chain length N=30) and the above alkylbenzene are metered in at an equimolar ratio relative to the polyoxyalkylene diol used. The metering amount and metering rate are set by a program-controlled peristaltic pump so that the total amount of the mixture is divided into approximately 18 individual sections of 11.4 g each. A 2-minute actual metering period is immediately followed by a 15-minute metering pause. This procedure is repeated in the same way for all 18 sections. After the addition of the stoichiometric amount of siloxane, a clear viscosity increase is observed. The end of the reaction can be clearly determined by the weakening of gas evolution. SiH measurement by the gas volume method confirms complete conversion. A viscosity of 6197 mPa·s and a weight-average molecular weight M of 91212 g / mol are obtained. w A colorless, highly viscous product is obtained having a PDI of 2.341.

[0119] Example 4 (according to the invention): A 1000 ml ground-glass four-neck flask equipped with a stainless steel Sigma stirrer, a peristaltic pump metering unit, an internal thermometer, and a reflux condenser with a gas outlet hose is initially charged with 160.9 g of dry polyoxyalkylene diol with a water content of <0.02%. The polyoxyalkylene diol 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 linear alkylbenzene with a boiling point range of approximately 240-314 °C. The mixture is heated to a temperature of 105 °C. Next, 201.0 mg of tris(pentafluorophenyl)borane (700 ppm based on the total amount of reactants) dissolved in 20 g of the above alkylbenzene is added. After stirring for 5 minutes, 160.0 g of α,ω-hydrogen siloxane (average chain length N=30) are metered in at an equimolar ratio to the polyoxyalkylene diol used. The metering amount and metering rate are set by a program-controlled peristaltic pump so that the total amount of hydrogen siloxane is metered in continuously within 221 minutes. After the stoichiometric amount of siloxane has been added, a clear increase in viscosity is observed. The end of the reaction can be clearly determined by the weakening of gas evolution. SiH determination by the gas volume method confirms complete conversion. A viscosity of 60210 mPa·s and a weight-average molecular weight M of 173600 g / mol are obtained. w A colorless, highly viscous product is obtained having a PDI of 3.095.

[0120] Example 5 (not according to the invention): A 1000 ml ground-glass four-neck flask equipped with a stainless steel Sigma stirrer, a peristaltic pump metering unit, an internal thermometer, and a reflux condenser with a gas outlet hose is initially charged with 115.8 g of dry polyoxyalkylene diol with a water content of <0.02%. The polyoxyalkylene diol 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 linear alkylbenzene with a boiling point range of approximately 240-314 °C. The mixture is heated to a temperature of 105 °C. Next, 123.0 mg of tris(pentafluorophenyl)borane (600 ppm based on the total amount of reactants) dissolved in 20 g of the above alkylbenzene is added. After stirring for 5 minutes, 180 g of a 1:1 mixture of α,ω-hydrogen siloxane (average chain length N=30) and the above alkylbenzene are metered in at an equimolar ratio relative to the polyoxyalkylene diol used. The metering amount and metering rate are set by a program-controlled peristaltic pump so that the total amount of hydrogen siloxane is metered in continuously within 17 minutes. After the addition of the stoichiometric amount of siloxane, a clear increase in viscosity is observed. The end of the reaction can be clearly determined by the weakening of gas evolution. SiH measurement by the gas volume method confirms complete conversion. A viscosity of 13780 mPa·s and a weight-average molecular weight M of 145100 g / mol are obtained. w A colorless, highly viscous product is obtained having a PDI of 2.689.

[0121] About Figures 1 to 6: Figures 1 to 6 illustrate Examples 1 to 5 of the present invention. Figures 1 to 5 show, in each case, the volume of hydrogen released as a function of the amount of hydrogen siloxane metered in Examples 1 to 5. The experiments differ, as previously described, with respect to the type of metering method (continuous or intermittent) and / or the metering rate. The dashed lines indicate the target conversion in each case. The solid lines indicate the actual conversion in each case.

[0122] In FIG. 6, the influence of the reaction procedure on the difference between the target and actual conversion is summarized as a function of the siloxane mass metered for Examples 1-5.

[0123] Example of the use of SiOC-bonded linear polydialkylsiloxane-polyether-block copolymers as cell openers in polyurethane formulations: The SiOC-bonded linear polydialkylsiloxane-polyether-block copolymers obtained in the above-described examples according to the present invention (Examples 1 to 4) and the example not according to the present invention (Example 5) were used as cell openers.

[0124] The following raw materials were used to prepare the polyurethane rigid foam: Rokopol® G 1000: Polyether polyol from Rokita Rokopol® D 1002: Polyether polyol from Rokita Desmophen® DE 10WF 15: Polyether polyol from Covestro Voranol® CP 3322: Polyether polyol from Dow PEG 600: Polyethylene glycol Stabilizer: TEGOSTAB® foam stabilizer from Evonik Operations GmbH, TEGOSTAB® B 84728 (One-component PU foam in a can) TEGOSTAB® B 8870 (packaging foam) TCPP: Tris(2-chloroisopropyl)phosphate (flame retardant) from Fyrol DABCO® DMDEE, an amine-based catalyst from Evonik Operations GmbH Dimethyl ether propane n-Butane Isobutane MDI: Desmodur® 44V20L from Covestro, diphenylmethane-4,4′-diisocyanate (MDI) including isomers and higher functional homologs.

[0125] Polyurethane foam production: For the one-component PU can foam tests, all ingredients of the formulation except for the blowing agent (see Table 1) were filled into an empty aerosol can. The can was then sealed with the appropriate valve, and finally the specified amount of blowing agent (LPG, DME) was added using a pressurized gas burette. The can was then shaken by hand for 1 minute and subsequently rotated on a rotary mixer for 30 minutes to create a homogeneous mixture and allow the formation of a homogeneous prepolymer.

[0126] To test for pore structure or internal defects, the contents of the can are discharged after 24 hours using a commercial foam gun. In this case, a foam strand is discharged onto paper, and after the foam has hardened, the quality of the foam is visually evaluated on a scale of 1 to 10 after 24 hours. To do this, the foam is cut in the middle. A value of 10 in this case represents a perfect foam with no internal defects or very fine cells; in contrast, a value of 1 represents collapsed foam or very coarse cells.

[0127] To determine the dimensional stability of one-component PU foams in cans, with respect to their shrinkage tendency or expansion behavior, FEICA (European Adhesives and Sealants Industry Association) method TM 1004:2013 ("Determination of the Dimensional Stability of OCF Canister Foams," Bruessel, February 19, 2013) is applied. For this purpose, two wooden panels are immersed in water for 30 seconds to allow the substrate to absorb a defined amount of water. Before applying the foam, the foam can is shaken by hand for 1 minute, discarding the initial spray of the can contents (approximately 3-5 seconds of foam gun operation). Subsequently, 15 g of foam is applied between the wooden panels. The wooden panels are fixed with spacers and wooden clamps, ensuring a constant distance of 2 cm between them. After 24 hours, the spacers and wooden clamps are removed, and the width between the two wooden panels is measured using a vernier caliper. Width measurements are repeated after 2, 3, 7, and 14 days, and the percentage difference compared to the starting 2 cm is recorded. In this case, as little shrinkage or post-expansion as possible is desirable, which correlates with a high open cell content of the foam.

[0128] For packaging foam formulations, the tests were carried out by the manual mixing method. For this, all components according to the formulation in Table 2, except for the polyisocyanate (MDI), were weighed into a beaker and mixed with a plate stirrer (6 cm diameter) at 1000 rpm for 30 seconds. Subsequently, the polyisocyanate (MDI) was added, and the reaction mixture was stirred with the described stirrer at 3000 rpm for 5 seconds, and the mixture was mixed in a 27 x 27 cm footprint. 2 The foam was removed from the mold after 10 minutes. After 24 hours, the foam was visually evaluated for shrinkage behavior. Also after 24 hours, the degree of internal defects and pore structure were visually evaluated on a scale of 1 to 10, with 10 representing a defect-free foam and 1 representing a highly defective foam.

[0129] [Table 1]

[0130] [Table 2]

[0131] The results of the foaming experiments on the one-component PU canned foams according to the examples are summarized in Table 3. Foam strands were produced as described above and subjected to DMS testing. The degree of internal defects or pore fineness was rated on a scale of 1 to 10. Dimensional stability (DMS) is expressed as the percentage of shrinkage (negative value) or expansion (positive value) of the foam's original thickness. Measurements were taken after 1, 2, 3, 7, and 14 days.

[0132] [Table 3]

[0133] This experiment clearly shows that the cell openers according to the invention (Examples 1 to 4) have a significantly improved dimensional stability compared to the non-inventive product from Example 5. In this case, no adverse effects on the pore structure and internal defects are observed.

[0134] The results of the foaming experiments on the packaging foams according to the examples are summarized in Table 4. The internal defects and pore structure were rated on a scale of 1 to 10, similar to the tests on the one-component PU canned foams.

[0135] [Table 4]

[0136] This experiment clearly shows that the cell opener according to the present invention effectively prevents shrinkage without adversely affecting the pore structure and internal defects (Example 11). In Example 12, which is not according to the present invention, slight shrinkage of the foam molding was observed after 24 hours, which was due to insufficient cell opening. At the same time, the pore structure and internal defects were worse than those of Example 11.

Claims

1. A process for preparing SiOC-bonded linear polydialkylsiloxane-polyoxyalkylene block copolymers having (AB) repeating units, comprising reacting a linear a,ω-(SiH)-functional polydialkylsiloxane (a) with a linear a,ω-(OH)-functional polyoxyalkylene (b) using a compound of one or more elements of main group III and / or minor group III as a 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 under controlled hydrogen evolution until quantitative SiH conversion occurs.

2. 2. The process according to claim 1, wherein the linear a,ω-(SiH)-functional polydialkylsiloxane used has a SiH value of 0.25 to 3.0 mol / kg, preferably 0.5 to 2.0 mol / kg, in particular 0.75 to 1.5 mol / kg.

3. The linear a,ω-(SiH)-functional polydialkylsiloxane has the general formula (I): M'-D ａ -M' formula (I) [In the formula, M'=[HR １ ２ Yes １／２ ] D=[R １ ２ SiO ２／２ ] a = 8 to 100, preferably 10 to 60, particularly preferably 20 to 50; R １ = independently of one another identical or different hydrocarbon radicals having 1 to 20 carbon atoms, preferably methyl, ethyl, propyl or butyl, particularly preferably methyl.

3. The method according to claim 1 or 2, characterized in that:

4. The linear a,ω-(OH)-functional polyoxyalkylene has the formula (II): HO-(C ｎ H( ２ｎ－ｍ） R ２ ｍ O-) ｂ -H Formula (II) in accordance with b=1 to 200, preferably 10 to 100, particularly preferably 25 to 60; n=2 to 4, m=0 or 1, R ２ 4. The process according to claim 1, wherein: = are, independently of one another, identical or different hydrocarbon radicals having 1 to 12 carbon atoms, preferably methyl, ethyl, propyl or butyl, particularly preferably methyl or ethyl.

5. 5. The process according to claim 1, wherein the oxyalkylene units in the linear a,ω-(OH)-functional polyoxyalkylene consist essentially of oxyethylene units and / or oxypropylene units, in particular a mixed unit of oxyethylene and oxypropylene units having an oxyethylene proportion of 25 to 70% by weight and 70 to 25% by weight of oxypropylene units, based on the total content of oxyalkylene units.

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

1.

7. 7. The process according to claim 1, characterized in that it is carried out in the presence of a solvent, which is added to reactants (a) and / or (b), the overall proportion of solvent based on the total amount of reactants (a), (b) and solvent being preferably 40% to 75% by weight, in particular 55% to 65% by weight, of solvent.

8. The reaction of reactants (a) and (b) is carried out by initially charging reactant (b) and metering reactant (a), said metering being carried out continuously or at intervals, in particular (i) heating reactant (b) to reaction temperature, adding catalyst and mixing thoroughly, and then metering in reactant (a) while controlling hydrogen evolution; (ii) reactant (b) is heated to the reaction temperature, the catalyst is added and mixed thoroughly, and then reactant (a) diluted with a solvent is metered in while controlling the hydrogen evolution; (iii) reactant (b) is heated to the reaction temperature, diluted with a solvent, the catalyst is added and mixed thoroughly, and then reactant (a) is metered in while controlling the hydrogen evolution; or (iv) reactant (b) is heated to the reaction temperature, diluted with a solvent, the catalyst is added and mixed thoroughly, and then reactant (a) diluted with a solvent is metered in while controlling the hydrogen evolution.

8. The method according to claim 1, wherein the method is carried out as follows:

9. 9. The process according to claim 1, wherein the reaction temperature for preparing the SiOC-bonded linear polydialkylsiloxane-polyoxyalkylene block copolymers having (AB) repeating units is in the range of 60°C to 140°C, in particular 100°C to 120°C.

10. 10. The process according to claim 1, wherein the catalyst is used in an amount of 0.01 to 0.2% by weight, preferably 0.03 to 0.10% by weight, based on the sum of the amounts of reactants (a) and (b), and the compound of an element of main group III, preferably a boron- and / or aluminum-containing catalyst, and / or the compound of an element of subgroup 3, preferably a scandium-, yttrium-, lanthanum- and / or lanthanoid-containing catalyst, is used.

11. 11. The method according to claim 1, wherein the rate at which component (a) is added to component (b) is such that the difference between the target conversion and the actual conversion is 0 to 10%, preferably 0 to 7.5%, particularly preferably 0 to 5%, in order to control the hydrogen generation.

12. 12. A SiOC-linked linear polydialkylsiloxane-polyether-block copolymer having (AB) repeating units produced by the method of any one of claims 1 to 11.

13. The overall proportion of siloxane blocks (A) is 20 to 60% by weight, in particular 40 to 50% by weight, and the overall proportion of polyoxyalkylene blocks (B) is 80 to 40% by weight, preferably 60 to 50% by weight, based on the entire block copolymer, and the block copolymer advantageously has a weight-average molecular weight M, measurable by GPC, of ​​at least 10,000 g / mol to about 250,000 g / mol, advantageously 15,000 g / mol to about 225,000 g / mol, in particular 20,000 g / mol to about 200,000 g / mol. ｗ 13. The block copolymer of claim 12, wherein

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

15. 14. Polyurethane foams, preferably rigid polyurethane foams, in particular rigid polyurethane foams with a high open cell content, produced using SiOC-bonded linear polydialkylsiloxane-polyether block copolymers having (AB) repeating units according to claim 12 or 13.

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

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