(Cyclic) aliphatic polycarbonate polyol compositions

Abstract

The present invention relates to (cyclo) aliphatic polycarbonate polyol compositions by reacting at least one (cyclo) aliphatic polyol and at least one alkyl carbonate in the presence of at least one basic catalyst and subsequently using at least one strong acid having a pKa value based on the corresponding acid-base pair of 1 or less and at least one ester having gt; medium-strong acids having a pKa value based on the corresponding acid-base pair of 1 to 7 can be obtained or produced by neutralizing the catalyst.

Description

[0001] The present invention relates to (cyclo)aliphatic polycarbonate polyol compositions, processes for their production and the use of certain neutralizing agents as terminating agents in the production of polycarbonate polyols. The invention further relates to aqueous polyurethane dispersions, two-component systems or thermoplastic polyurethanes obtainable from said (cyclo)aliphatic polycarbonate polyols, and to coatings or moldings obtainable from said articles.

[0002] Oligocarbonate polyols or polycarbonate polyols are important precursors, for example in the production of plastics, paints and adhesives. They react, for example, with isocyanates, epoxides, (cyclic) esters, acids or acid anhydrides (DE-A1955902, EP-A0343572). In principle, they can be produced from aliphatic polyols by reaction with phosgene (for example DE-A1595446, US-A4533729); dichloro carbonate (for example DE-A857948), diaryl carbonate (for example DE-A1915908), cyclic carbonate (for example DE-A2523352, US-A787632, DE-A1495299) or dialkyl carbonate (for example DE-A2555805, EP-A0343572, EP0533275).

[0003] WO2018 / 114827A1 describes a process for producing (cyclo)aliphatic polycarbonate polyols, in which an organic sulfonic acid having a molecular weight of 250 to 1000 g / mol and at least one branched or unbranched alkyl substitution having at least 4 carbon atoms is used as a strong neutralizing agent for a basic catalyst, such that the reactivity of the polyol, in particular towards isocyanate groups, is not increased. Comparative examples in this document include the neutralization of the basic catalyst with dibutyl phosphate, which did not result in sufficient neutralization.

[0004] A disadvantage of the process in WO2018 / 114827A1 is that the organic sulfonic acid used itself has a catalytic effect, so that an increase in the reactivity of the (cyclo)aliphatic polycarbonate polyol can still occur despite successful neutralization.

[0005] Since the synthesis of (cyclo)aliphatic polycarbonate polyols is a polymerization reaction without complex purification steps, for example, the continuously fluctuating quality of the input materials and reaction management must be taken into account, and it is not possible to fully foresee how the reactivity of individual batches of (cyclo)aliphatic polycarbonate polyols towards other co-reactants (such as isocyanates) will behave.

[0006] Accordingly, an object of the present invention is to provide an (alicyclic) aliphatic polycarbonate polyol composition that is neither colored nor turbid and does not exhibit increased reactivity, especially towards isocyanates. Another object of the present invention is to provide a process for producing an (alicyclic) aliphatic polycarbonate polyol that neither causes coloration nor turbidity in the product and does not increase the reactivity of the (alicyclic) aliphatic polycarbonate polyol, especially towards isocyanates.

[0007] In view of this need, the subject matter of the present invention is an (alicyclic) aliphatic polycarbonate polyol composition obtainable or producible by reacting at least one (alicyclic) aliphatic polyol and at least one alkyl carbonate in the presence of at least one basic catalyst and subsequently neutralizing the catalyst with at least one strong acid having a pKa value of 1 or lower based on the corresponding acid-base pair and at least one medium-strength acid having a pKa value of >1 to 7 based on the corresponding acid-base pair.

[0008] Also in view of this need, the subject matter of the present invention is a process for producing an (alicyclic) aliphatic polycarbonate polyol composition according to the present invention, which comprises the steps of:

[0009] a) reacting at least one (alicyclic) aliphatic polyol and at least one alkyl carbonate in the presence of at least one basic catalyst, and

[0010] b) neutralizing by adding at least one strong acid having a pKa value of 1 or lower based on the corresponding acid-base pair and at least one medium-strength acid having a pKa value of >1 to 7 based on the corresponding acid-base pair,

[0011] wherein step b) is carried out after step a).

[0012] It is particularly surprising that the addition of a weak acid, such as dibutyl phosphate, results in a lower reactivity of highly reactive (alicyclic) aliphatic polycarbonate polyols, but hardly affects (i.e., neither accelerates nor makes it more reaction-inert) the reactivity of less reactive, but still sufficiently reactive, (alicyclic) aliphatic polycarbonate polyols. This is particularly evident from examples using, for example, 100 ppm of dibutyl phosphate.

[0013] In the present context, the pKa values of the present invention are defined under standard conditions at 25 °C. The reference is oxonium (also known as oxidanium, hydroxonium or hydronium) or protonated water (H3O + )). The pKa value of the oxonium ion is -1.74.

[0014] For polybasic acids, the lowest value is considered to be the pKa value in this case. For example, for phosphoric acid, it is pKa1 of 2.16, rather than the further values pKa2 = 7.20 and pKa3 = 12.33.

[0015] According to the present invention, the terms "comprising", "containing", etc. are preferably understood to mean "consisting essentially of", and particularly preferably to mean "consisting of". Further embodiments mentioned in the claims and the description can be combined as required, provided that the context does not clearly indicate the contrary.

[0016] As used herein, "at least one" means one or more, such as 2, 3, 4, 5, 6, 7, 8, 9 or more. With respect to the components of the compounds described herein, this value does not refer to the absolute number of molecules, but rather to the type of component. "At least one (cyclic) aliphatic polyol" is thus understood to mean, for example, that there may be only one type of (cyclic) aliphatic polyol or multiple different types of (cyclic) aliphatic polyols, rather than indicating the amounts of the individual compounds.

[0017] The numerical values given herein without decimal places each refer to the fully shown value with one decimal place. Thus, for example, "99%" represents "99.0%".

[0018] A numerical range given in the format "x to y" includes the stated values. If multiple preferred numerical ranges are given in this format, it is understood that all ranges obtained by combination of the various endpoints are also included.

[0019] In the present invention, the neutralization in step b) is also referred to as termination. Thus, strong acids and moderately strong acids are also collectively or individually referred to as terminators hereinafter. The combination of the basic catalyst of the present invention with strong acids and moderately strong acids is also referred to as a catalyst system in the context of the present invention.

[0020] In the present invention, the terms "subsequent neutralization" and "wherein step b) is carried out after step a)" should be understood to mean, respectively, that the neutralization with strong acids and medium strong acids can be carried out essentially only after the reaction of at least one (cyclo)aliphatic polyol and at least one alkyl carbonate in the presence of at least one basic catalyst, and that step b) can be carried out essentially only after the reaction in step a) in the presence of a basic catalyst. However, this term should not be understood to mean that step b) must be carried out immediately after step a). Thus, it is possible to carry out any desired optional steps, such as purification steps, after step a) and then carry out step b), wherein the neutralization of the reaction product obtained in step a) is preferably carried out with strong acids to an extent of 70% to 110%, preferably to an extent of 90% to 100%, particularly preferably to an extent of 95% to 99%, and with medium strong acids to an extent of 1% to 50%, preferably to an extent of 2% to 30%, particularly preferably to an extent of 3% to 20% (in each case in moles, based on the molar amount of the base in the basic catalyst from a), where in the case of polyacids, only the group with the lowest pKa is taken into account). The molar amount of the acid is based on the initial amount of the basic catalyst used in step a) (not the amount after the first neutralization sub-step).

[0021] Preferably, after the reaction in step a), there is a further reaction step for removing the terminal alkyl carbonate groups from the polymer. For this purpose, preferably under reduced pressure, the reaction mixture is subjected to an elevated temperature of 150 °C to 250 °C, preferably 170 °C to 220 °C, particularly preferably 180 °C to 210 °C, and the alcohol formed is distilled off.

[0022] (Cyclo)aliphatic polycarbonate polyols should be understood here to mean that there are alicyclic structural units and / or branched aliphatic structural units and / or unbranched aliphatic structural units. Preferably, unbranched aliphatic structural units are present.

[0023] Suitable basic catalysts are, for example, substances having a pKb value based on the corresponding acid-base pair of less than 7, preferably less than 2, very particularly preferably less than 0. Specific examples include sodium hydroxide, potassium hydroxide, sodium methoxide, potassium methoxide, sodium acetate, potassium acetate, titanium tetraisopropoxide, titanium tetrabutoxide, other titanium alkoxides, ytterbium acetylacetonate, other rare earth acetylacetonates, zinc acetylacetonate, tin acetylacetonate, sodium acetylacetonate, tin octoate, technical mixtures thereof, aluminium isopropoxide, other aluminium alkoxides, and strong amine bases such as 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) or 1,5-diazabicyclo[4.3.0]non-5-ene (DBN).

[0024] In another preferred embodiment, the basic catalyst is a basic salt selected from the alkali metal series. The alkali metal series is to be understood as meaning lithium, sodium, potassium, rubidium and cesium, particularly preferably lithium, sodium and potassium, very particularly preferably sodium and potassium, and especially preferably sodium.

[0025] As anions of suitable basic catalysts, preference is given to those which are basic or which are able to exhibit basic properties under the reaction conditions. Examples include: hydroxides, oxides, carbonates, hydrogencarbonates, phosphates, silicates, alkoxides, such as methoxides, ethoxides, propoxides, and salts of organic acids, such as formates, acetates, propionates. Such salts can also be generated in-situ, for example by reacting a metal alkali metal with the corresponding alcohol or acid.

[0026] Specific examples of particularly preferred suitable basic catalysts are sodium hydroxide, potassium hydroxide, sodium methoxide, potassium methoxide, sodium acetate, potassium acetate. Sodium methoxide or potassium methoxide are particularly preferred.

[0027] Mixtures of two or more basic catalysts can also be used according to the invention.

[0028] The basic catalyst used according to the invention can be used both as a solid and as a solution.

[0029] The concentration of the catalyst and / or mixture used according to the invention is preferably between 1 ppm and 10,000 ppm, more preferably between 5 ppm and 500 ppm, particularly preferably between 20 ppm and 150 ppm, in each case based on the total weight of the (cyclic) aliphatic polyol and the dialkyl carbonate used.

[0030] In order to produce an aliphatic oligocarbonate polyol having a molar mass between 500 and 5000 g / mol, the reaction temperature of the transesterification reaction of the organic carbonate with the aliphatic polyol in the presence of the catalyst used according to the invention is preferably between 40 °C and 250 °C, preferably between 60 °C and 200 °C, particularly preferably between 90 °C and 170 °C, especially between 110 °C and 160 °C.

[0031] Alkyl carbonates which can be used include, for example, dimethyl carbonate (DMC), diethyl carbonate (DEC), ethylene carbonate, propylene carbonate. Preference is given to using a dialkyl carbonate, dimethyl carbonate or diethyl carbonate. Very particular preference is given to using dimethyl carbonate.

[0032] Comonomers useful for the transesterification of organic carbonates using a catalyst according to the invention to produce aliphatic oligocarbonate polyols include (cyclo)aliphatic polyols having 2 to 25 carbon atoms and an OH functionality ≥ 2 (linear, cyclic, branched, unbranched, saturated or unsaturated), where the OH functionality can be primary, secondary or tertiary, preferably primary or secondary, and any desired mixture of these OH functionalities can also be present. Particularly preferably, the OH functionality is primary.

[0033] Examples include: ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 2-ethylhexanediol, 2-methyl-1,3-propanediol, cyclohexanedimethanol, dimer diol, diethylene glycol, dipropylene glycol, tripropylene glycol, dibutylene glycol, trimethylolpropane, pentaerythritol, hydrogenated bisphenol A, tricyclodecane dimethanol.

[0034] Also usable according to the invention are polyols obtained by the ring-opening reaction of lactones with aliphatic alcohols (linear, cyclic, branched, unbranched, saturated or unsaturated) having an OH functionality ≥ 2 (primary, secondary or tertiary), such as adducts of ε-caprolactone with 1,6-hexanediol or ε-caprolactone with trimethylolpropane and mixtures thereof.

[0035] Short-chain polyethers can also be used, preferably polyethylene glycol, polypropylene glycol or polybutylene glycol. The molecular weight of such short-chain polyethers is not greater than 800 g / mol, preferably less than 500 g / mol. Such short-chain polyethers are preferably bifunctional.

[0036] Finally, mixtures of different above-mentioned (cyclo)aliphatic polyols can also be used as reactants.

[0037] Preferred are aliphatic or alicyclic, branched or unbranched primary or secondary polyols having an OH functionality ≥ 2. Particularly preferred are aliphatic, branched or unbranched primary polyols having a functionality ≥ 2. Very particularly preferably, 1,6-hexanediol and / or 1,5-pentanediol are used.

[0038] The transesterification reaction between organic carbonates and aliphatic polyols using a catalyst according to the invention can be carried out both at atmospheric pressure and at a reduced or elevated pressure of 10 -3 to 10 3 bar, preferably 1 to 10 bar.

[0039] It is essential for the present invention to add a terminator to the (cyclo)aliphatic polycarbonate polyol, preferably after removing the terminal alkyl carbonate groups. Used as terminator according to the invention are at least one strong acid having a pKa value of 1 or lower based on the corresponding acid-base pair and at least one medium-strength acid having a pKa value of >1 to 7 based on the corresponding acid-base pair.

[0040] In another preferred embodiment, the at least one strong acid has a pKa value of -1 or lower, preferably -2 or lower, based on the corresponding acid-base pair.

[0041] In another preferred embodiment, the at least one strong acid is an organic sulfonic acid, preferably an alkylsulfonic acid or an arylsulfonic acid, particularly preferably an arylsulfonic acid having at least one alkyl substituent, very particularly preferably an organic sulfonic acid having a molecular weight of from 250 to 1000 g / mol, preferably from 300 to 500 g / mol and at least one branched or unbranched alkyl substituent having at least 4 carbon atoms. The organic sulfonic acid preferably has a molecular weight of from 300 to 500 g / mol and at least one branched or unbranched alkyl substituent having at least 8 carbon atoms. Examples of such organic sulfonic acids are tetrapropylenebenzenesulfonic acid or dodecylbenzenesulfonic acid or isomers thereof. Preferably, the organic sulfonic acid is tetrapropylenebenzenesulfonic acid, dodecylbenzenesulfonic acid and / or a technical isomer mixture of dodecylbenzenesulfonic acid. Particularly preferably, it is dodecylbenzenesulfonic acid or a technical isomer mixture thereof.

[0042] In another preferred embodiment, the at least one medium-strength acid has a pKa value of from 2 to 5 based on the corresponding acid-base pair.

[0043] In another preferred embodiment, the at least one medium-strength acid is a hydrogen phosphate, preferably dibutyl phosphate or phosphoric acid, in particular dibutyl phosphate.

[0044] The terminator composed of a strong acid and a medium-strength acid is used to neutralize the basic catalyst and is used in another preferred embodiment such that the neutralization of the basic catalyst is carried out to an extent of 70% to 110%, preferably to an extent of 90% to 100%, particularly preferably to an extent of 95% to 99% with the strong acid and to an extent of 1% to 50%, preferably to an extent of 2% to 30%, particularly preferably to an extent of 3% to 20% (in each case in moles, based on the molar amount of the base, where in the case of polybasic acids, only the group having the lowest pKa is counted).

[0045] Another subject of the present invention is also an (alicyclic) aliphatic polycarbonate polyol composition which contains at least one (alicyclic) aliphatic polycarbonate polyol, 10 to 200 weight ppm of sulfur based on the total weight of the (alicyclic) aliphatic polycarbonate polyol composition, and 0.1 to 10 weight ppm of phosphorus based on the total weight of the (alicyclic) aliphatic polycarbonate polyol composition. The contents of sulfur and phosphorus are based on the chemical bonding ratio of the elements and are determined by elemental analysis after microwave digestion.

[0046] The (alicyclic) aliphatic polycarbonate polyol according to the invention and / or the (alicyclic) aliphatic polycarbonate polyol composition according to the invention has a number-average molecular weight (Mn) of 250 g / mol to 5000 g / mol, preferably 500 g / mol to 3000 g / mol, particularly preferably 800 g / mol to 2500 g / mol. The number-average molecular weight is determined by combining the OH functionality with the OH value.

[0047] The OH functionality of the (alicyclic) aliphatic polycarbonate polyol according to the invention and / or the (alicyclic) aliphatic polycarbonate polyol composition according to the invention is between 1.8 and 3.0; preferably between 1.9 and 2.5, very particularly preferably between 1.94 and 2.00. The OH functionality can be determined by 1 H NMR spectroscopy.

[0048] Another subject of the present invention is also the use of at least one strong acid having a pKa value of 1 or lower based on the corresponding acid-base pair and at least one medium strong acid having a pKa value of >1 to 7 based on the corresponding acid-base pair as terminators in the production of an (alicyclic) aliphatic polycarbonate polyol composition to reduce the reactivity of the polycarbonate polyol and / or improve its turbidity stability.

[0049] The (alicyclic) aliphatic polycarbonate polyol according to the invention and / or the (alicyclic) aliphatic polycarbonate polyol composition according to the invention are, for example, suitable as structural units for the production of aqueous polyurethane dispersions. These polyurethane dispersions are used, for example, as paint raw materials for paint coatings, where in particular the combination of hydrolysis resistance, chemical resistance and high elasticity as well as impact strength is important. Another use of these polyurethane dispersions containing the (alicyclic) aliphatic polycarbonate diol according to the invention and / or the (alicyclic) aliphatic polycarbonate polyol composition according to the invention is fabric coating. Here, too, the combination of hydrolysis resistance, chemical resistance and high elasticity is important.

[0050] Another subject of the present invention is thus also an aqueous polyurethane dispersion which contains at least one (cyclo)aliphatic polycarbonate polyol according to the invention which reacts with at least one isocyanate group-containing compound and / or a (cyclo)aliphatic polycarbonate polyol composition according to the invention which contains at least one which reacts with at least one isocyanate group-containing compound. The aqueous polyurethane dispersion according to the invention is produced in a manner known per se to the person skilled in the art (for example as known from US 7,452,525 B1) by reacting the polyol according to the invention with at least one isocyanate group-containing compound. Hydrophilic compounds, optionally chain extenders and optionally other short-chain or long-chain polyols are also used in this case.

[0051] Another subject of the invention is a two-component system which contains component A) and component B), where component A) comprises at least one (cyclo)aliphatic polycarbonate polyol according to the invention and / or at least one (cyclo)aliphatic polycarbonate polyol composition according to the invention and component B) comprises at least one polyisocyanate. The (cyclo)aliphatic polycarbonate polyol according to the invention and / or the (cyclo)aliphatic polycarbonate polyol composition according to the invention can also be used in two-component polyurethane casting resin systems. In this case, lightfastness, yellowing resistance at high temperatures and chemical resistance are important.

[0052] The (cyclo)aliphatic polycarbonate polyol according to the invention and / or the (cyclo)aliphatic polycarbonate polyol composition according to the invention can also be used for the production of thermoplastic polyurethanes and polyesters. Such plastics are particularly impact-resistant and abrasion-resistant, chemical-resistant and, depending on the composition, also lightfast. Another subject of the present invention is thus a thermoplastic polyurethane which contains at least one (cyclo)aliphatic polycarbonate polyol according to the invention which reacts with at least one isocyanate group-containing compound and / or a (cyclo)aliphatic polycarbonate polyol composition according to the invention which contains at least one which reacts with at least one isocyanate group-containing compound.

[0053] Another subject of the present invention is a molded article or a coating which can be obtained or has been obtained from at least one thermoplastic polyurethane according to the invention or by curing at least one aqueous polyurethane dispersion according to the invention or by curing at least one two-component system according to the invention.

[0054] Suitable isocyanate group-containing compounds are any desired compounds known to the person skilled in the art. The invention is explained in more detail below with reference to examples and comparative examples, but is not limited thereto. Examples

[0055] Unless otherwise specified, all percentage data relate to percentages by weight.

[0056] The determination of the NCO content in % is carried out by back - titration with 0.1 mol / l hydrochloric acid after reaction with butylamine, based on DIN EN ISO 11909:2007.

[0057] The OH value is determined according to DIN 53240 - 1:2013.

[0058] The viscosity measurement of the polycarbonate polyol is carried out at 23 °C at a shear rate of 47.94 / s using a plate - plate rotational viscometer RotoVisko 1 from Haake GmbH, Germany, according to DIN EN ISO 3219:1990.

[0059] The contents of sulfur and phosphorus are determined by elemental analysis after microwave digestion.

[0060] Polycarbonate diol is produced according to Example 7 of WO2018 / 114827A1. The resulting product is partially neutralized: 0.61 g of 4 - dodecylbenzenesulfonic acid is admixed at 100 °C per 1000 g of the polycarbonate diol produced according to Example 7 and stirred for about 1 hour.

[0061] Obviously, the reactivity of the individual batches of polycarbonate diol fluctuates significantly. Four batches of polycarbonate diol (batches A, B, C, and D) are further analyzed below. A reactivity test is established in order to be able to classify the batches with respect to reactivity.

[0062] Testing the reactivity of polycarbonate diol

[0063] To test the reactivity of the polycarbonate diol, these are dissolved in butyl acetate at a concentration of 66% and reacted with twice the amount (in terms of the NCO - OH ratio) of toluene diisocyanate (Desmodur T 80, Covestro AG, Leverkusen, NCO:OH = 2.0) at 80 °C. This reaction is carried out while regularly checking the isocyanate content by titration.

[0064] Reactivity measurement 1 (batch A - highly reactive batch):

[0065] Time after the start of the reaction [min] Isocyanate content [%] 30 2.1 60 1.7 120 [Unable to measure, sample gelled]

[0066] Batch A is too reactive for most applications. Despite a high molar excess of the isocyanate component, this test batch gelled after 120 °C, thus indicating a high degree of side reactions.

[0067] Reactivity measurement 2 (batch B - reactive batch):

[0068] Time after the start of the reaction [min] Isocyanate content [%] 30 2.6 60 2.2 120 1.8

[0069] The reactivity of Batch B is significantly lower than that of Batch A, but it is still too reactive for some applications.

[0070] Reactivity Measurement 3 (Batch C - Medium Reactivity Batch):

[0071] Time after the start of the reaction [min] Isocyanate content [%] 30 3.0 60 2.6 120 2.3

[0072] Batch C corresponds to the typical range of the required reactivity.

[0073] In the following examples of the present invention, in each case, 0.1 g of dibutyl phosphate was further added to 1000 g of the polycarbonate diol from the above batches at 100 °C with stirring and stirred for 1 hour. After subsequent cooling, the corresponding reactivity measurements were carried out.

[0074] Furthermore, 500 g each were filled into transparent glass bottles, the bottles were sealed and stored in a circulating air oven at 70 °C for 17 hours, and the optical evaluation was carried out directly. None of the samples with subsequent addition of dibutyl phosphate showed any perceptible product turbidity or discoloration.

[0075] Reactivity Measurement 4 (Batch A - Highly Reactive Batch with an additional 100 ppm of dibutyl phosphate):

[0076] Time after the start of the reaction [min] Isocyanate content [%] 30 2.6 60 2.3 120 2.2

[0077] Reactivity Measurement 5 (Batch B - Reactive Batch with an additional 100 ppm of dibutyl phosphate):

[0078] Time after the start of the reaction [min] Isocyanate content [%] 30 2.9 60 2.5 120 2.3

[0079] Reactivity Measurement 6 (Batch C - Medium Reactivity Batch with an additional 100 ppm of dibutyl phosphate):

[0080] Time after the start of the reaction [min] Isocyanate content [%] 30 2.9 60 2.5 120 2.3

[0081] It was found that all three batches with the addition of dibutyl phosphate had good medium reactivity. The reaction rates of the highly reactive batch and the reactive batch decreased significantly, and the reaction was thus controllable. Surprisingly, the reaction rate of the medium reactivity batch - which was already within a manageable range before the addition of dibutyl phosphate - was hardly affected by the addition of dibutyl phosphate. This is very beneficial because it enables the convergence of reactivity at various starting levels and despite the addition of the same amount of a lower-strength acid.

[0082] The reactivity of the three products after the addition of dibutyl phosphate was approximately the same in each case. Therefore, if necessary, acceleration can be achieved by adding a catalyst without the need to check the reactivity of individual batches or adjust the catalyst dosage according to the batch.

[0083] To test the reactivity of the polycarbonate diol towards aliphatic isocyanates, another sample of the above polycarbonate diol was dissolved in butyl acetate at a concentration of 67% and reacted with twice the amount (in terms of the NCO-OH ratio) of hexamethylene diisocyanate (Desmodur H, Covestro AG, Leverkusen, NCO:OH = 2.0) at 80 °C. The reaction was carried out while regularly checking the isocyanate content by titration.

[0084] Reactivity measurement 7 (batch D - reactivity batch):

[0085]

[0086]

[0087] In the following examples of the present invention, in each case, 0.01 g of phosphoric acid (85% concentration in water) was further added to 1000 g of the polycarbonate diol from the above batch at 100 °C with stirring and stirred for 1 hour. After subsequent cooling, the corresponding reactivity measurements were carried out.

[0088] Reactivity measurement 8 (batch D - reactivity batch after addition of 10 ppm phosphoric acid (85% concentration)):

[0089] Time after the start of the reaction [min] Isocyanate content [%] 30 4.5 60 4.4 120 4.2 240 3.6

[0090] It is obvious that the added phosphoric acid also causes a decrease in reactivity, and the effect is also achieved in aliphatic isocyanates that are more reaction-inert compared to aromatic isocyanates.

Claims

1. An (alicyclic) aliphatic polycarbonate polyol composition obtainable or producible by reacting at least one (alicyclic) aliphatic polyol and at least one alkyl carbonate in the presence of at least one basic catalyst and subsequently neutralizing the catalyst with at least one strong acid having a pKa value of 1 or lower based on the corresponding acid-base pair and at least one medium-strength acid having a pKa value of >1 to 7 based on the corresponding acid-base pair.

2. The (cyclo)aliphatic polycarbonate polyol composition according to claim 1, characterized in that The basic catalyst is a substance having a pKb value of less than 7, preferably less than 2, and very particularly preferably less than 0 based on the corresponding acid-base pair.

3. The (cyclo)aliphatic polycarbonate polyol composition according to claim 1 or 2, characterized in that The basic catalyst is a basic salt selected from the alkali metal series, preferably sodium alkoxide or potassium alkoxide.

4. The (cyclo)aliphatic polycarbonate polyol composition according to any one of claims 1 to 3, characterized in that The at least one strong acid has a pKa value of -1 or lower, preferably -2 or lower based on the corresponding acid-base pair.

5. The (cyclo)aliphatic polycarbonate polyol composition according to any one of claims 1 to 4, characterized in that The at least one medium-strength acid has a pKa value of 2 to 5 based on the corresponding acid-base pair.

6. The (cyclo)aliphatic polycarbonate polyol composition according to any one of claims 1 to 4, characterized in that The at least one strong acid is an organic sulfonic acid, preferably an alkylsulfonic acid or an arylsulfonic acid, particularly preferably an arylsulfonic acid having at least one alkyl substituent, very particularly preferably an organic sulfonic acid, and / or the at least one medium-strength acid is a hydrogen phosphate, preferably dibutyl phosphate or phosphoric acid, especially dibutyl phosphate.

7. A method for producing an (alicyclic) aliphatic polycarbonate polyol composition according to any one of claims 1 to 6, which comprises the steps of: a) reacting at least one (alicyclic) aliphatic polyol and at least one alkyl carbonate in the presence of at least one basic catalyst, and b) neutralizing by adding at least one strong acid having a pKa value of 1 or lower based on the corresponding acid-base pair and at least one medium-strength acid having a pKa value of >1 to 7 based on the corresponding acid-base pair, wherein step b) is carried out at least partially after step a).

8. The method for producing an (alicyclic) aliphatic polycarbonate polyol composition according to claim 7, characterized in that The basic catalyst is present in a concentration between 1 ppm and 10,000 ppm, preferably between 5 ppm and 500 ppm, particularly preferably between 20 ppm and 150 ppm, in each case based on the total weight of the (alicyclic) aliphatic polyol and alkyl carbonate used.

9. The method for producing an (alicyclic) aliphatic polycarbonate polyol composition according to claim 7, characterized in that The neutralization of the basic catalyst is carried out to an extent of 70% to 110%, preferably to an extent of 90% to 100%, particularly preferably to an extent of 95% to 99% with the strong acid, and to an extent of 1% to 50%, preferably to an extent of 2% to 30%, particularly preferably to an extent of 3% to 20% with the medium-strength acid, in each case in moles, based on the molar amount of the base, where in the case of a polybasic acid, only the group having the lowest pKa is taken into account.

10. An (alicyclic) aliphatic polycarbonate polyol composition containing at least one (alicyclic) aliphatic polycarbonate polyol, 10 to 200 weight ppm of sulfur based on the total weight of the (alicyclic) aliphatic polycarbonate polyol composition and 0.1 to 10 weight ppm of phosphorus based on the total weight of the (alicyclic) aliphatic polycarbonate polyol composition, wherein the contents of sulfur and phosphorus are chemically bonded.

11. Use of at least one strong acid having a pKa value based on the corresponding acid-base pair of 1 or lower, at least one moderately strong acid having a pKa value based on the corresponding acid-base pair of > 1 to 7, at least one organic sulfonic acid having a molecular weight of 250 to 1000 g / mol and at least one branched or unbranched alkyl substitution having at least 4 carbon atoms as a terminator in the production of a (cyclo)aliphatic polycarbonate polyol composition to reduce the reactivity of the polycarbonate polyol and / or improve its turbidity stability.

12. An aqueous polyurethane dispersion containing at least one (cyclo)aliphatic polycarbonate polyol composition according to any one of claims 1 to 6 or according to claim 10, which reacts with at least one isocyanate group-containing compound.

13. A two-component system containing component A) and component B), wherein component A) comprises at least one (cyclo)aliphatic polycarbonate polyol composition of the present invention according to any one of claims 1 to 6 or according to claim 10, and component B) comprises at least one polyisocyanate.

14. A thermoplastic polyurethane containing at least one (cyclo)aliphatic polycarbonate polyol composition of the present invention according to any one of claims 1 to 6 or according to claim 10, which reacts with at least one isocyanate group-containing compound.

15. A molded article or coating obtainable or obtained from at least one thermoplastic polyurethane according to claim 14 or by curing at least one aqueous polyurethane dispersion according to claim 12 or by curing at least one two-component system according to claim 13.

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