Method for producing alkyl silicone resin

Abstract

The present invention relates to a process for producing an alkyl silicone resin (A) comprising at least 80% by weight of a compound of the general formula (I) R 1 a (R 2 O) b (HO) d R 3 c SiO (4‑a‑b‑c‑d) / 2 (I), provided that the sum of a+b+c is less than or equal to 3, in at least 50% of the units of formula (I) the sum of a+b is equal to 0 or 1, and in at least 40% of the units of formula (I) c is equal to 1, the alkoxy group R 2 The content of O is equal to 3-20% by weight. In the first reaction step (R1), the general formula (II) R 1 a R 3 c Si(OR 2 ) (4‑a‑c) The alkylalkoxysilane (Al) of (II) selectively reacts with a pK of at most 5 S A pure acid (S) with a pK value of at most 5, at least 5% by weight S Aqueous solution of acid (S) or general formula (III) R 1 a R 3 c Si(X) (4‑a‑c) (III) wherein X represents a halogen atom, R 1 、R 3 , a and c have the above meanings. Water is then added in at least one further reaction step (R2), R 1 、R 2 、R 3 , a, b, c and d have the meanings mentioned in claim 1.

Description

Technical Field

[0001] The present invention relates to a method for producing alkyl silicone resins by acidic hydrolysis of alkylalkoxysilanes. Background Art

[0002] Organosilicon compounds have a long history of use in building preservation due to their excellent impregnation action towards water and dirt, their environmental compatibility and their physiological safety.

[0003] The established impregnation compositions herein comprise alkoxysilanes having a hydrophobic alkyl group, of which alkyl groups having 8 carbon atoms, more particularly n-octyl or 1,4,4-trimethylpentyl, are particularly well-established. Typical representatives of this class of hydrophobic silanes are n-octyltriethoxysilane and 1,4,4-trimethylpentyltriethoxysilane.

[0004] Two fundamental forms of application can be distinguished here. In the first case, pre-existing structures, such as concrete bridges, house facades, or roof tiles, are retroactively hydrophobized with a coating formulation. In this case, the coating material, applied at least in conjunction with porous building materials, is also able to penetrate the substrate and thus develop at least a certain depth of effect. Thus, in contrast to a merely surface-applied varnish or paint, relatively minor surface damage does not automatically lead to a loss of the hydrophobic protective effect. However, in the case of merely surface-impregnated materials, more severe damage (either drilling, cutting, sawing, or breaking edges) does lead to a loss of protective effect in the affected area.

[0005] Although retrospective surface hydrophobization is often the only feasible impregnation method for existing structures, when producing components based on hydraulic binders (such as concrete or fiber cement), the hydrophobizing agent can even be added before the curing operation. The advantage of this mass hydrophobization is that the entire volume of the component (not just its surface) is protected against water. Therefore, the protective effect is not lost if the component is damaged or intentionally sawn open or drilled. In addition, the mass hydrophobization saves the additional operating step of retrospectively coating the cured component.

[0006] A particularly important position in the building elements to be hydrophobized is occupied by fiber-reinforced cementitious composite materials.

[0007] To produce these materials, a highly diluted slurry of fibers and cement (usually common Portland cement) is typically first dewatered to form films of approximately 0.3 mm thickness, which are then wound onto rolls of the desired thickness. The rolled fiber-cement layer is then cut and flattened to form planar panels, which can then be cut into the desired shape and size. Curing can occur over several days (typically 1-2 weeks) in air or more rapidly by high-pressure treatment at elevated temperatures. For the latter method, 40-60% sand can also be added to the fiber cement and reacted with excess lime in the cement at elevated autoclave temperatures to form calcium silicate hydrates.

[0008] The fibers used are mainly asbestos, cellulose, polyvinyl acetate (PVA), polyvinyl alcohol (PVOH) or polypropylene (PP) fibers. However, carbon fibers and polyacrylonitrile fibers can also be used. With regard to their properties, asbestos fibers, in particular, have many advantages because they are not only strong and hard, but also as inorganic materials they can be firmly bonded to cementitious matrices. For example, in contrast to cellulose fibers, asbestos fibers are also corrosion-resistant.

[0009] However, due to the health risks posed by asbestos, this fiber material is in retreat, especially in Western industrial countries; in Europe and North America, related products have completely disappeared.

[0010] In the case of non-autoclaved fiber cement boards, the health-acceptable alternatives used are usually combinations of cellulose fibers with PVA, PVOH, PP, or PET fibers. Since PVA, PP, and PET are destroyed by the autoclaving process, this method typically uses only cellulose as an asbestos substitute. However, because fiber cement boards without PVA, PP, PET, or asbestos have only moderate mechanical properties, in Europe and the US, autoclaved products are primarily used for facades, while non-autoclaved products are typically used for load-bearing walls or roof elements.

[0011] Especially for exterior applications, hydrophobized fiber cement boards are increasingly used; due to the advantages mentioned above, the trend away from retrospective coatings and towards mass hydrophobization is clear.

[0012] The overall hydrophobization of fiber cement components using formulations whose components include alkoxysilanes with hydrophobizing alkyl groups has been known for a long time and was described in DE 411449 as early as 1991.

[0013] However, one of the disadvantages of using alkoxysilanes is that during use, large amounts of alcohol are released from the silanes by hydrolysis of their alkoxysilyl groups. In the case of the aforementioned alkyltriethoxysilanes whose alkyl groups contain 8 carbon atoms, the weight of ethanol released corresponds almost exactly to 50% of the amount of silane used.

[0014] This poses a major problem particularly for the bulk hydrophobization of fiber cement, since, as mentioned above, a highly diluted slurry of fibers and cement is dewatered there. To avoid excessive wastewater, the process water removed during dewatering is usually returned to the process. When silanes are used for bulk hydrophobization, the released highly water-soluble alcohol remains in the process water and thus gradually accumulates with each cycle of water returned to the process. Its removal would necessitate a technically very complex process and is rarely feasible in practice for cost reasons.

[0015] Furthermore, it has been found that monomeric alkylalkoxysilanes exhibit only moderate effectiveness when used for global hydrophobization.

[0016] As an improvement, as described in WO 2019 / 141377, it has been proposed to use corresponding oligomeric alkylalkoxysilane resins instead of monomeric alkylalkoxysilanes in building preservation, particularly in connection with the overall hydrophobization of fiber cement. This results in a decisive improvement.

[0017] WO 2019 / 141377 also describes a method for producing these resins, wherein, in a continuous operation, the corresponding monomeric alkyltrichlorosilane is reacted with a mixture of water and an alcohol to produce an oligomeric alkyl silicone resin. This operation produces extremely large amounts of hydrogen chloride as a byproduct. While this method can be very cost-effective, as described in WO 2019 / 141377, this advantage can only be exploited when implemented in very specific equipment. If this equipment is not available, the operation is complex and therefore has low economic benefits simply because of the very large amounts of hydrogen chloride that are released and ideally should be recycled. Equally complex and therefore expensive is the required safe transportation and reliable handling of the alkyltrichlorosilane reactant, which can spontaneously release hydrogen chloride upon contact with air.

[0018] What is needed here is a simple and rapid operation, starting from substantially less critical monomeric alkylalkoxysilanes, which are oligomerized into corresponding resins by reaction with an appropriate amount of water. However, the problem with this chemical method is that the production of the required hydrophobic alkyl silicone resin requires equally hydrophobic alkylalkoxysilanes. Logically, these hydrophobic alkylalkoxysilanes are not miscible with water. Therefore, the corresponding reaction must occur in a two-phase system, which always leads to a long reaction time because the chemical reaction can only occur at the phase boundary. This is on the one hand quite detrimental to the space-time yield, and on the other hand may also have an adverse effect on product quality because long reaction times at elevated temperatures can not only lead to secondary reactions but also to undesirable discoloration. And, of course, such an operation is also desired, wherein the product is directly obtained with sufficiently good quality without further purification. Summary of the Invention

[0019] It was therefore an object of the present invention to provide a process for producing hydrophobic alkyl silicone resins (A) which no longer has the disadvantages and limitations affecting the processes described in the prior art.

[0020] The subject of the present invention is a process for producing an alkyl silicone resin (A) comprising at least 80% by weight of units of the general formula (I)

[0021] R 1 a (R 2 O) b (HO) d R 3 c SiO (4-a-b-c-d) / 2 (I),

[0022] in

[0023] R 1 which may be identical or different and are monovalent, SiC-bonded, unsubstituted or substituted aliphatic hydrocarbon groups having not more than 4 carbon atoms,

[0024] R 2 may be the same or different and are hydrogen or a monovalent, unsubstituted or substituted hydrocarbon radical having not more than 4 carbon atoms,

[0025] R 3 which may be identical or different and are monovalent, SiC-bonded, unsubstituted or substituted hydrocarbon radicals having at least 5 carbon atoms,

[0026] a is 0, 1, 2, or 3,

[0027] b is 0, 1, 2, or 3, and

[0028] c is 0, 1 or 2, provided that the sum of a+b+c is less than or equal to 3, and in at least 50% of the units of formula (I), the sum of a+b is 0 or 1, and in at least 40% of the units of formula (I), c is 1,

[0029] d is 0 or 1, and

[0030] Among them, the alkoxy group R 2 The amount of O is 3-20wt%,

[0031] wherein the alkylalkoxysilane (A1) of the general formula (II) is reacted in the first reaction step (R1) with a silane having a pK of not more than 5 a pure acid (S), or with at least 5 wt% of a compound having a pK not greater than 5 a An aqueous solution of an acid (S) or a mixture of a halogenated silane compound (A2) of the general formula (III) R 1 a R 3 c Si(OR 2 ) (4-a-c) (II),

[0032] where R 1 、R 2 、R 3 , a and c have the above definitions,

[0033] R 1 a R 3 c Si(X) (4-a-c) (III),

[0034] Where X is a halogen atom and R 1 、R 3 , a and c have the above definitions,

[0035] And subsequently water is added in at least one further reaction step (R2).

[0036] The optionally used halosilane compounds (A2) spontaneously release hydrogen halide on contact with water, so that their effect is similar to that of direct addition of the corresponding hydrohalic acid.

[0037] pK as a measure of acid strength a are familiar to the skilled person; suitable definitions are to be found in "Grundlagen derallgemeinen und anorganischen Chemie", Hans-Rudolf Christen, 9th edition, 1988, section 10.3.

[0038] It is preferred to use a halogenated silane compound (A2) or a pK a The acid (S) of not more than 3 is more preferably a halogenated silane compound (A2) or phosphoric acid, phosphonic acid, sulfonic acid, sulfuric acid or a hydrohalic acid, and particularly preferably a halogenated silane compound (A2) or a hydrohalic acid. A preferred hydrohalic acid is hydrochloric acid.

[0039] The halosilane compound (A2) or the acid (S) is preferably used in an amount of 0.01 to 100 g, more preferably in an amount of 0.1 to 25 g, particularly preferably in an amount of 0.2 to 10 g, in each case based on 1000 g of alkoxysilane (A1). When the acid (S) is used as an aqueous solution, as is preferred, these amounts are based on the pure acid (S) present in the aqueous solution.

[0040] When an acid (S) is used, it is preferably used in the form of an aqueous solution having an acid concentration of at least 10 wt %, more preferably at least 15 wt % and especially preferably at least 20 wt %.

[0041] In a preferred version, the halosilane compound (A2) or at least 5% by weight, more preferably at least 10% by weight, particularly preferably at least 20% by weight, of aqueous hydrochloric acid is used in an amount of 0.1 g to 25 g, preferably 0.2 g to 10 g, based on 1000 g of alkoxysilane (A1), this amount being based on the halosilane compound (A2) or the pure hydrochloric acid present in the aqueous hydrochloric acid solution.

[0042] In a preferred embodiment, the partial reaction step (R1) is to stir or otherwise uniformly mix the reaction mixture after adding the halosilane compound (A2), the pure acid (S) or the aqueous solution of the acid (S) until the halosilane compound (A2), the pure acid (S) or the aqueous solution of the acid (S) have completely dissolved in the reaction mixture and the latter is clear.

[0043] Reaction step (R1) is preferably carried out at a temperature between 0°C and 100°C, more preferably between 10°C and 100°C, more particularly between 20°C and 90°C.

[0044] In a preferred embodiment, the addition of water in reaction step (R2) is carried out at a low rate such that the reaction mixture remains clear and without noticeable turbidity throughout the addition of water.

[0045] In a preferred embodiment, the partial reaction step (R2) is to homogeneously mix the reaction mixture, more particularly to stir it, after the addition of water is complete, for a further 1 min to 10 h, more preferably for 5 min to 5 h, and particularly preferably for 15 min to 3 h, in order to achieve complete reaction between the added water and the silane (A1).

[0046] Reaction step (R2) is preferably carried out at a temperature between 0°C and 100°C, more preferably between 20°C and 100°C, especially preferably between 40°C and 90°C.

[0047] The present invention is based on the surprising discovery that, when using the process according to the invention, the reaction between the alkylalkoxysilane (A1) and water, referred to as silane hydrolysis, can be carried out completely or at least largely in a single-phase reaction mixture, despite the hydrophobicity of the silane (A1) used. The single-phase nature of this mixture is evident from the fact that at the end of reaction step (R1), the reaction mixture is clear and remains clear during the addition of water in the second reaction step (R2). In these cases, the reaction proceeds very rapidly, and in particular, a significant exothermic heating of the reaction mixture is evident during the addition of water.

[0048] In contrast, according to the invention, if the acid (S) and water used as catalyst are not added continuously to the alkoxysilane (A1), but rather in this case in the form of a more diluted acid solution, the result is a two-phase reaction mixture, as expected. In this case, the reaction mixture remains turbid until the added water has been almost completely consumed by the reaction at the end of the reaction. Due to this two-phase behavior, even with very intensive stirring, reaction times of >10 h are required. Since the reaction progresses very slowly, exothermic heating of the reaction mixture is not observable.

[0049] The same practically expected results are achieved if water and alkoxysilane (A1) are first mixed and the reaction is subsequently initiated by adding a catalytic amount of acid. Also under these conditions, the reaction mixture remains biphasic and turbid, no exothermic heating is observable, and the same long reaction time is required.

[0050] Finally, the same, relatively unfavorable reaction profile is also found when a mixture of water and acidic catalyst is introduced and the alkoxysilane (A1) is metered into this mixture.

[0051] Finally, the type of catalyst is also crucial. Thus, bases are generally well-established and therefore well-established catalysts for silane hydrolysis and condensation. However, if, as in the case of the reaction according to the present invention, a basic catalyst is used instead of an acid, the reaction mixture exhibits the expected behavior, remaining biphasic and turbid, regardless of the specific procedure, until the added water has been almost completely consumed by the reaction at the end of the reaction. Also under these conditions, very long reaction times are necessary, and due to the slow course of the reaction, no exothermic heating of the reaction mixture is observed. It is noteworthy that the use of basic catalysis, as opposed to the acidic catalysis according to the present invention, does not lead to any better results, even with the order of addition and reaction scheme according to the present invention.

[0052] The groups R are preferably given 1 is an unsubstituted group, ie, an alkyl group, such as methyl, ethyl, n-propyl, isopropyl, 1-n-butyl, 2-n-butyl, isobutyl and tert-butyl, among which methyl and ethyl are particularly preferred, and methyl is especially preferred.

[0053] Group R 2 An example is for the group R 1 Definitions indicated. Group R 2 Preferred are alkyl groups optionally substituted by halogen atoms and having 1 to 4 carbon atoms, more particularly methyl and ethyl groups.

[0054] Group R 3 Preferably, it contains an unsubstituted cyclic, branched or unbranched alkyl group having 6 to 18 carbon atoms. 3 Examples of are n-hexyl, cyclohexyl, n-octyl, 1,4,4-trimethylpentyl, decyl, dodecyl, tetradecyl, hexadecyl or octadecyl radicals.

[0055] Group R 3 More preferably, it comprises an alkyl group having 8 to 16 carbon atoms, more particularly an n-octyl, 1,4,4-trimethylpentyl or n-hexadecyl group.

[0056] The alkyl silicone resin (A) preferably comprises at least 90 wt% of units of formula (I). More preferably, component (A) consists only of units of formula (I).

[0057] In the alkyl silicone resin (A), preferably, all groups R 1 At least 90 mol% of the groups R 2 At least 90 mol % of the groups R are methyl, ethyl, propyl or isopropyl groups. In the alkyl silicone resin (A), preferably, all groups R 3At least 90 mol % of the alkyl groups are unsubstituted alkyl groups having 8 to 16 carbon atoms.

[0058] In the alkyl silicone resin (A), independently of one another, a is preferably 0 or 1, b is preferably 0, 1 or 2, c is preferably 0 or 1, and d is preferably 0. Preferred alkyl silicone resins (A) are those which have at least 40%, more preferably at least 60%, of units of the formula (I) in which a is 0 and c is 1, in each case based on the total number of units of the formula (I). In a specific embodiment of the invention, the alkyl silicone resin (A) has only units of the formula (I) in which a is 0 and c is 1.

[0059] One version of the invention uses alkyl silicone resins (A) having up to 50%, more preferably up to 40%, very preferably up to 20%, of units of the general formula (I) in which a has the value 2, based in each case on the total number of units of the general formula (I).

[0060] Preferred alkyl silicone resins (A) are those having 8 to 65%, more particularly 10 to 45%, very particularly 12 to 16%, of units of the formula (I) in which b has the value 0, based in each case on the total number of units of the formula (I).

[0061] Preferred alkyl silicone resins (A) are those which have 30 to 70%, more particularly 45 to 63%, of units of the formula (I) in which b has the value 1, based in each case on the total number of units of the formula (I).

[0062] Preferred alkyl silicone resins (A) are those having 5 to 45%, more particularly 22 to 40%, of units of the formula (I) in which b has the value 2, based in each case on the total number of units of the formula (I).

[0063] Preferred alkyl silicone resins (A) are those having 0 to 5%, more preferably 0 to 2%, more particularly 0 to 1%, of units of the formula (I) in which b has the value 3, based in each case on the total number of units of the formula (I).

[0064] Preferred alkyl silicone resins (A) are those which have at least 80%, more preferably at least 90%, more particularly at least 95%, of units of the formula (I) in which d is 0, based in each case on the total number of units of the general formula (I).

[0065] Examples of alkyl silicone resins (A) are organopolysiloxane resins which consist to an extent of at least 95%, preferably exclusively, of the formula SiO 4 / 2 、Si(OR 4 )O 3 / 2 、Si(OR 4)2O 2 / 2 and Si(OR 4 )3O 1 / 2 (Q) unit; formula Alk-SiO 3 / 2 、Alk-Si(OR 4 )O 2 / 2 and Alk-Si(OR 4 )2O 1 / 2 、Me-SiO 3 / 2 、Me-Si(OR 4 )O 2 / 2 and Me-Si(OR 4 )2O 1 / 2 (T) unit; formula Me2SiO 2 / 2 and Me2Si(OR 4 )O 1 / 2 (D) unit; and formula Me3SiO 1 / 2 wherein Me is a methyl group, Alk is an unsubstituted alkyl group having 8 to 16 carbon atoms, and R 4 is an alkyl group having 1 to 4 carbon atoms, and the resin preferably contains 0-2 moles of (Q) units, 0-2 moles of (D) units, and 0-2 moles of (M) units per mole of (T) units.

[0066] Preferred examples of alkyl silicone resins (A) are organopolysiloxane resins which consist at least 95%, preferably exclusively, of the formula AlkSiO 3 / 2 、AlkSi(OR 4 )O 2 / 2 and AlkSi(OR 4 )2O 1 / 2 T unit, and there is also the formula MeSiO 3 / 2 、MeSi(OR 4 )O 2 / 2 and MeSi(OR 4 )2O 1 / 2 T unit, and there is also the formula Me2SiO 2 / 2 and Me2Si(OR 4 )O 1 / 2 The D unit is composed of Me, Alk and R 4 Having the above definitions, and the molar ratio of (T) to (D) units is between 1.0 and 10.0.

[0067] Other preferred examples of alkyl silicone resins (A) are organopolysiloxane resins which consist to an extent of at least 95%, preferably exclusively, of the formula AlkSiO 3 / 2 、AlkSi(OR 4 )O 2 / 2 and AlkSi(OR4 )2O 1 / 2 T unit, and there is also the formula MeSiO 3 / 2 、MeSi(OR 4 )O 2 / 2 and MeSi(OR 4 )2O 1 / 2 The T unit is composed of Me, Alk and R 4 Having the above definition, the molar ratio of Alk to Me units is from 0.5 to 4.0.

[0068] Further preferred examples of alkyl silicone resins (A) are organopolysiloxane resins which consist to an extent of at least 95%, preferably exclusively, of the formula AlkSiO 3 / 2 、AlkSi(OR 4 )O 2 / 2 and AlkSi(OR 4 )2O 1 / 2 The T unit consists of Alk and R 4 With the above definition.

[0069] Particularly preferred examples of the alkyl silicone resin (A) are organopolysiloxane resins having one of the compositions described in the preceding four paragraphs, wherein Alk is an n-octyl, 1,4,4-trimethylpentyl or n-hexadecyl group, more specifically an n-octyl or 1,4,4-trimethylpentyl group.

[0070] The alkyl silicone resin (A) preferably has an average molar mass (number average) M of at least 400 g / mol and more preferably at least 600 g / mol. n Average molar mass M n Preferably it is at most 400,000 g / mol, more preferably at most 10,000 g / mol, more particularly at most 1,500 g / mol.

[0071] Molar mass was determined by GPC. Instruments: Agilent 1200 Iso pump, Agilent 1200 autosampler, Agilent 1260 column oven, Agilent 1200 RID detector, Agilent 300×7.5 mm Oligopore 4500D cutoff column, column material: highly cross-linked polystyrene / divinylbenzene, 25% eluent: toluene, flow rate: 0.7 ml / min, injection volume: 10 μl, concentration: 1 g / l (in toluene), PDMS (polydimethylsiloxane) calibration (Mp 28500D, Mp 25200D, Mp 10500D, Mp 5100D, Mp 4160D, Mp 1110D, Mp 311D).

[0072] At 23° C. and 1000 hPa, the alkyl silicone resin (A) may be solid or liquid, and the alkyl silicone resin (A) is preferably liquid. The silicone resin (A) preferably has a viscosity of 10 to 100,000 mPas, preferably 50 to 1000 mPas, more particularly 100 to 500 mPas.

[0073] In the context of the present invention, the viscosity is determined after adjusting to 23° C. a DV 3P rotational viscometer from A. Paar (Brookfield system) according to ISO 2555 using spindle 5 at 2.5 rpm.

[0074] In the first reaction step (R1), either pure alkylalkoxysilanes (A1) of the general formula (II) or two or more alkoxysilanes (A1) can be used.

[0075] In a preferred embodiment of the process according to the invention, reaction steps (R1) and (R2) according to the invention are followed by a further reaction step (R3) in which a base (B) is added in an amount that is greater than the amount of base (B) required to completely neutralize the amount of acid (S) present in the reaction mixture when the base (B) is added or greater than the amount of base (B) required to completely neutralize the amount of hydrogen halide released from the halosilane compound (A2) and present when the base (B) is added.

[0076] Here, the base (B) preferably has a pK of not more than 5. b and more preferably a pK no greater than 3.6 b The base (B) is particularly preferably a hydroxide or carbonate of an alkali metal or alkaline earth metal, and the use of alkali metal hydroxides such as sodium hydroxide and potassium hydroxide is particularly advantageous.

[0077] Likewise preferably used as base (B) are alkali metal alkoxides, more preferably sodium and potassium alkoxides, very particularly sodium ethoxide and potassium methoxide.

[0078] pK b The measure of base strength is known to the skilled worker; a suitable definition is to be found in "Grundlagen derallgemeinen und anorganischen Chemie", Hans-Rudolf Christen, 9th edition, 1988, section 10.3.

[0079] The base (B) can be added in pure form or in the form of an aqueous or alcoholic solution. When the base (B) is a solid, it is preferably added in the form of an aqueous solution. In particular, an alkali metal alkoxide is used as the alcoholic solution. When the base (B) is used in the form of an aqueous or alcoholic solution, the concentration of the base (B) in the solution is preferably at least 5 wt%, particularly preferably at least 10 wt%, and even more preferably at least 15 wt%. The upper limit of each concentration is determined by the maximum solubility of the base (B).

[0080] In a preferred embodiment, the partial reaction step (R3) is that after the addition of the base (B) is completed, the reaction mixture is stirred or otherwise uniformly mixed together for a period of 1 min to 20 h, more preferably 5 min to 5 h, and particularly preferably 15 min to 3 h, after the addition of the base (B) is completed.

[0081] At the end of reaction step (R3), the reaction mixture preferably has a pH of at least 6.0, more preferably at least 6.5 and especially preferably at least 7.

[0082] Reaction step (R3) is preferably carried out at a temperature between 0°C and 100°C, more preferably between 20°C and 100°C, especially preferably between 40°C and 90°C.

[0083] This preferred embodiment results from the further surprising finding that the reaction between silane (A1) and water (known as silane hydrolysis) can indeed be carried out in a single-phase reaction mixture and therefore works particularly well using the acidic catalysis of the invention, but under acidic conditions the relatively large number of silanol functions (Si—OH groups) (formed as a result of silane hydrolysis) do not condense or condense only very slowly.

[0084] This is a disadvantage because in this way a relatively high portion of the silanol functional groups remains in the final product (A). During storage, these silanol groups can slowly react with the alkoxy groups of the resin (A) of the invention to form Si-O-Si ridges and release alcohol R 2 OH. Since the latter are generally highly flammable, this lowers the flash point of the resulting resin (A), which is now contaminated with alcohol. For the end users of the alkyl silicone resin (A), usually manufacturers of cement products (such as fiber cement slag), who are not equipped to handle flammable substances, this is often a serious problem.

[0085] Here, in addition to the likewise acidic silanol groups, the pH in reaction step (R3) does not have to be greater than 7—all that is crucial is that the amount of base (B) is greater than that required to neutralize the amount of acid still present in the reaction mixture when the base (B) is added.

[0086] The base (B) added in excess reacts with some of the Si-OH groups present in the reaction mixture, and the reaction mixture is therefore ultimately located in the pH range of the silanol-silanolate buffer system. However, surprisingly, it has been found that even under these conditions, i.e. even at pH levels well below 7, the silanolate groups present undergo a reaction with the alkoxysilyl groups (R) present in the resin (A). 2 O—Si groups) and possibly also rapid condensation with the silanol groups present to form Si—O—Si bridges. In other words, even under the conditions of a silanol-siliconate buffer system, i.e. at a pH level below 7, there is still rapid decomposition of the silanol groups.

[0087] Thus, in many cases, another phenomenon that occurs is that the reaction mixture immediately after the addition of the base (B) still has a pH far below 6, possibly even far below 5, which however itself, even without the addition of further base (B), rises at the end of reaction step (R3) to a level greater than 6.0, preferably 6.5, more particularly at least 7. This generally occurs within 1 to a maximum of 60 minutes, typically within 1 to a maximum of 15 minutes.

[0088] In a particularly preferred embodiment (AF1), reaction step (R3) is carried out as follows: after the end of reaction steps (R1) and (R2), a base (B) is added to the reaction mixture in an amount greater than the amount required to completely neutralize the acid (S) used in reaction step (R1) or the hydrogen halide released from the halosilane compound (A2) used in reaction step 1.

[0089] The alcohol R released in the process of the invention 2 The OH groups are preferably removed distillatively in a further process step (R4).

[0090] The distillation is preferably performed at a liquid phase temperature of 60 to 150°C and more preferably 70 to 120°C.

[0091] The distillation is preferably carried out at a pressure of 0.01 mbar to ambient pressure, more preferably at least partially under reduced pressure of 0.1 mbar to 100 mbar and especially preferably at least partially at a pressure of 1 mbar to 50 mbar.

[0092] The prepared alkyl silicone resin (A) preferably has an alcohol content of not more than 2 wt%, more preferably not more than 1 wt%, and especially preferably not more than 0.5 wt%.

[0093] When carrying out the particularly preferred embodiment (AF1) of the process according to the invention, the entire amount of alcohol released is preferably distilled off after the end of reaction step (R3). In this way, only a single distillation step is required to obtain the above-mentioned preferred low alcohol content in the alkyl silicone resin (A).

[0094] It is of course conceivable to insert a distillation step as early as after the end of process step (R2). However, this has the disadvantage that the alcohol (R3) released in process step (R4) is not removed. 2 OH), or an additional distillation step is required after the reaction step (R3). Therefore, in embodiment (AF1), this procedure is not preferred.

[0095] It is also conceivable to distill off part of the alcohol obtained early in process step (R2) (R 2 OH). However, since unreacted water can also be distilled off in that case, it is difficult to adjust the amount of water remaining in the reaction mixture with sufficient accuracy under these conditions, and thus adjust the degree of oligomerization of the resulting alkyl silicone resin (A). For this reason, this procedure is also not preferred in embodiment (AF1).

[0096] When carrying out the particularly preferred embodiment (AF1) of the process according to the invention, the pH obtained at the end of process step (R3) can be adjusted in a further process step (R5) to a pH in the largely neutral range, more preferably to a pH of 6.5 to 7.5, by adding an acid or base. This is particularly preferred when the amount of base used in process step (R3) is already sufficient for the resulting reaction mixture to have a pH of >7.5. In this case, process step (R5) can be carried out before or after the distillation (R4).

[0097] When carrying out preferred embodiment (AF1) of the process according to the invention, the salts obtained in process step (R3) due to the addition of the base and, where appropriate, the salts obtained in neutralization (R5) are preferably removed by a filtration step (R6). In this case, the filtration step (R6) can be carried out both after and before the distillation step (R4) and / or the neutralization (R5). Filtration is preferably the last process step.

[0098] Filtration (R6) can optionally be carried out with the aid of filter aids. Filter aids are chemically inert substances that physically and mechanically support filtration. Filter aids are used to make it easier to clean the actual filter or filter element, or to prevent solids from the suspension from clogging the filter or entering the filtrate. All recognized filter aids can be used. Examples of commonly used filter aids are cellulose, silica gel, diatomaceous earth, or perlite.

[0099] In another particularly preferred embodiment (AF2), reaction step (R3) is carried out as follows:

[0100] using a halosilane compound (A2) or a hydrohalic acid in reaction step (R1), particular preference being given to an aqueous hydrochloric acid solution having an acid concentration of at least 5 wt. % or a chlorosilane compound (A2) (i.e. a compound of formula (III) in which X is a chlorine atom),

[0101] During or preferably after reaction step (R2), at least 30%, preferably at least 60%, more preferably at least 80%, particularly preferably at least 90% of the alcohol released in the preceding reaction step (R 2 OH), wherein at least some, preferably a major part, of the hydrogen halide present in the reaction mixture is also distilled off,

[0102] • and subsequently adding a base (B) in an amount greater than that required to completely neutralize the amount of hydrohalic acid remaining in the reaction mixture.

[0103] Preferably, the alcohol (R 2 OH) and the distillation of the hydrohalic acid is such that less than 1000 ppm, more preferably less than 500 ppm, of the hydrohalic acid remaining in the reaction mixture is obtained. If the hydrohalic acid is hydrochloric acid, i.e. if in reaction step 1 hydrochloric acid or chlorosilane (A2) is used and the distillation is carried out such that the resulting reaction mixture contains less than 5 wt %, preferably less than 1 wt %, of alcohol (R 2 OH), this is particularly easy to achieve.

[0104] The distillation is preferably performed at a liquid phase temperature of 60°C to 150°C and more preferably at a liquid phase temperature of 70°C to 120°C.

[0105] The distillation is preferably carried out at a pressure of 0.01 mbar to ambient pressure, more preferably at least partially under reduced pressure of 0.1 mbar to 100 mbar and especially preferably at least partially at a pressure of 1 mbar to 50 mbar.

[0106] Likewise in the case of preferred embodiment (AF2), after completion of process step (R3), in a further distillation step (R4) any alcohol R still present in the reaction mixture is distilled off. 2 OH. Even in the preceding joint distillative removal of alcohol and acid, further alcohol (R 2 OH), also very low alcohol contents preferred according to the invention have been achieved, which is preferred.

[0107] This distillation (R4) is carried out exactly as described above, giving a product (A) having the above-mentioned preferred and particularly preferred low alcohol content.

[0108] In the case of particularly preferred embodiment (AF2), a neutralization step (R5) and / or a filtration step (R6) can also be performed. The procedure for these steps can be the same as described for embodiment (AF1). The order of the individual process steps (R4), (R5), and (R6) can also be changed as required in the case of preferred embodiment (AF2).

[0109] However, in the case of the particularly preferred embodiment (AF2), method steps (R5) and (R6) are preferably omitted. Method step (R5) can generally be omitted because only a very small amount of base needs to be added in method step (R3), so that, with suitable implementation of the method, even without an additional neutralization step, a final product (A) is successfully obtained, which, due to the aforementioned silanol-siliconate buffer, has a pH of 6.5 to 7.5. Method step (R6) can also generally be omitted because the amount of salt formed in method step (R3) is extremely small and therefore no longer disruptive in use.

[0110] The alkyl silicone resin (A) prepared according to the present invention is particularly useful for the overall hydrophobization of fiber cement. This use, its various forms, and the resulting advantages are described in detail in WO 2019 / 141377, starting on page 15, line 21, to page 20, line 27, and in the Examples. The corresponding paragraphs and Examples from WO 2019 / 141377 are therefore incorporated into the disclosure of this patent specification.

[0111] In the examples described below, all viscosity figures are based on a temperature of 23° C. Unless otherwise indicated, the following examples were conducted at ambient atmospheric pressure (in other words, about 1000 hPa) and at room temperature (in other words, about 23° C.) or at a temperature approximately at which the reactants would be combined at room temperature without additional heating or cooling, and at a relative humidity of about 50%. Furthermore, unless otherwise indicated, all parts and percentages are given by weight. DETAILED DESCRIPTION

[0112] Example

[0113] Inventive Example 1: Particularly Preferred Embodiment (AF1) of the Inventive Process

[0114] Device:

[0115] The reaction was carried out in a 1000 ml three-necked flask equipped with a heating device (oil bath with magnetic stirrer), a KPG stirrer, a dropping funnel and a reflux condenser.

[0116] Chemicals used in reaction steps (R1) to (R3):

[0117] 600.0 g of 1,4,4-trimethylpentyltriethoxysilane (2.17 mol)

[0118] 2.5 g of 25 wt% aqueous hydrochloric acid solution (0.017 mol HCl, 0.104 mol H2O)

[0119] 40.6 g water (2.26 mol)

[0120] 3.0 g of 50 wt% aqueous sodium hydroxide solution (0.038 mol NaOH, 0.083

[0121] mol H2O)

[0122] program

[0123] 600.0 g of 1,4,4-trimethylpentyltriethoxysilane were introduced and heated to 65° C. At this temperature, 2.5 g of 25% aqueous HCl solution were metered in at a uniform rate over the course of 20 minutes with vigorous stirring. The reaction mixture initially experienced slight turbidity (two-phase system). Stirring was continued at 65° C. for 10 minutes, at which point the reaction mixture became clear again.

[0124] Thereafter, 40.6 g of water were metered in over the course of 30 minutes, while maintaining the temperature. A noticeable exothermic reaction began, and the reaction temperature rose to ~70°C. To limit the temperature to 70°C, the reaction mixture was cooled after reaching this temperature. The reaction mixture remained clear throughout the entire time. After the metering was complete, stirring was continued at 65°C for 60 minutes.

[0125] Thereafter, without changing the temperature, a pH of ˜9-10 was established by adding 50% aqueous sodium hydroxide solution (3.0 g). Sodium chloride precipitated as a white solid, but the reaction mixture remained monophasic. It was then stirred at 65° C. for 30 min.

[0126] It was cooled to room temperature and neutralized to pH 7 by adding 25% HCl (2.1 g). Stirring was continued for 30 min, during which the pH could rise again. In that case, the pH had to be re-established at 7 by adding a small amount of acid.

[0127] After replacing the reflux condenser with a Claisen condenser with a short column (approximately 1-2 trays), low boilers were distilled off at an oil bath temperature of 120°C and atmospheric pressure until no further distillate was produced. The liquidus temperature was continuously raised to 110°C. During this operation, ~225 g of distillate were obtained. The pressure was then reduced to 10 mbar, yielding a further ~5 g of distillate. After ~15 min, no further distillate was produced even at this pressure, and the pressure was reduced to 5 mbar. Under these conditions, even very small residues of ethanol and / or water were removed from the reaction mixture for a further 30 min.

[0128] 406 g of a residue were obtained in the form of a colorless liquid containing sodium chloride formed as a white solid.

[0129] filter:

[0130] 10 g of Seitz EF filter aid were added to the material to be filtered (about 2.5 wt %) and distributed uniformly by stirring.

[0131] After homogenization of the filter aid, the suspension was placed at room temperature in a pressure suction filter on K100 filter material, and the filter was closed and subjected to compressed air (approximately 5 bar).

[0132] After a short time, the filtrate begins to flow into the corresponding collection container. It is clear from the start. The compressed air feed is continued until there is no more outflow.

[0133] Afterwards, turn off the compressed air, depressurize the pressure suction filter, and only then open the filter for cleaning.

[0134] Characterization of the final product (alkyl silicone resin (A)):

[0135] The final product was a clear liquid with a viscosity of 185 mPas (measured by the method indicated in the description).

[0136] pass 1 H and 29 The final product was analyzed by Si-NMR distribution to determine the amount of ethoxy groups, the distribution of Si units in the various condensation stages, the amount of silanol groups remaining in the product, and the amount of free ethanol remaining in the product. The results obtained in this case are as follows:

[0137] Ethoxy content: 13.4 wt% (based on the total weight of the final product)

[0138] Silanol content: 94ppm (calculated as O 1 / 2 H (molar mass = 9, based on the total weight of the final product)

[0139] Ethanol content: 0.03 wt% (based on the total weight of the final product)

[0140] Distribution of Si units at various condensation stages:

[0141] Si(OEt)3 unit: 0.8 mol% (monosilane)

[0142] Si(OEt)2O 1 / 2 Unit: 16.2 mol%

[0143] Si(OEt)O 2 / 2 Unit: 55.6 mol%

[0144] SiO 3 / 2 Unit: 27.4 mol%

[0145] Example 2 of the present invention: The present invention program of a particularly preferred embodiment (AF1)

[0146] The procedure was exactly the same as in Example 1 of the present invention, with the only difference being that the same amount of n-octyltriethoxysilane was used instead of 600.0 g of 1,4,4-trimethylpentyltriethoxysilane. The reaction process was confirmed to be exactly the same.

[0147] Characterization of the final product (alkyl silicone resin (A)):

[0148] The final product was a clear liquid with a viscosity of 223 mPas (measured by the method indicated in the description).

[0149] pass 1 H and 29 The final product was analyzed by Si-NMR distribution to determine the amount of ethoxy groups, the distribution of Si units in the various condensation stages, the amount of silanol groups remaining in the product, and the amount of free ethanol remaining in the product. The results obtained in this case are as follows:

[0150] Ethoxy content: 13.8 wt% (based on the total weight of the final product)

[0151] Silanol content: 35ppm (calculated as O 1 / 2 H (molar mass = 9, based on the total weight of the final product)

[0152] Ethanol content: 0.10 wt% (based on the total weight of the final product)

[0153] Distribution of Si units at various condensation stages:

[0154] Si(OEt)3 unit: 1.0 mol% (monosilane)

[0155] Si(OEt)2O1 / 2 Unit: 18.3 mol%

[0156] Si(OEt)O 2 / 2 Unit: 50.3 mol%

[0157] SiO 3 / 2 Unit: 30.4 mol%

[0158] Example 3 of the present invention: The present invention program of a particularly preferred embodiment (AF1)

[0159] The procedure is the same as in Example 1 of the present invention, with the following differences:

[0160] Instead of 2.5 g of 25 wt% aqueous hydrochloric acid, 2.0 g of

[0161] 1,4,4-Trimethylpentyltrichlorosilane (0.008 mol) was used as a catalyst. In the reaction with water, this silane released 0.024 mmol of hydrogen chloride.

[0162] Instead of 3.0 g of 50 wt% aqueous sodium hydroxide solution, reaction step (R3) used 4.7 g of a methanol solution of sodium methoxide (0.026 mol NaOCH3).

[0163] • The neutralization step (R5) was omitted because the reaction mixture already had a pH of 7 after the addition of sodium methoxide in reaction step (R3).

[0164] The other reaction scheme and reaction process are exactly the same as those described in Example 1 of the present invention.

[0165] Characterization of the final product (alkyl silicone resin (A)):

[0166] The final product was a clear liquid with a viscosity of 175 mPas (measured by the method indicated in the description).

[0167] pass 1 H and 29 The final product was analyzed by Si-NMR distribution, wherein the amount of ethoxy groups, the distribution of Si units in the various condensation stages, the amount of silanol groups remaining in the product and the amount of free ethanol remaining in the product were determined. The results obtained in this case are as follows:

[0168] Ethoxy content: 13.1 wt% (based on the total weight of the final product)

[0169] Methoxy content: 0.3 wt% (based on the total weight of the final product)

[0170] Silanol content: 174ppm (calculated as O 1 / 2H (molar mass = 9, based on the total weight of the final product)

[0171] Ethanol content: 0.05 wt% (based on the total weight of the final product)

[0172] Distribution of Si units at various condensation stages:

[0173] Si(OR)3 unit: 0.9 mol% (monosilane)

[0174] Si(OR)2O 1 / 2 Unit: 18.1 mol%

[0175] Si(OR)O 2 / 2 Unit: 55.8 mol%

[0176] SiO 3 / 2 Unit: 25.2 mol%

[0177] Wherein R = ethyl or methyl group.

[0178] Comparative Example 1: Non-inventive process reaction (joint addition of acid (S) and water):

[0179] The same apparatus, formulations, and amounts of the same chemicals as in Example 1 of the present invention were used. However, before the reaction began, hydrochloric acid and water were mixed and metered into trimethylpentyltriethoxysilane over 30 minutes at a reaction temperature of 65°C with vigorous stirring. Immediately after the addition began, the reaction mixture became turbid. Heating of the reaction mixture was not noticeable. After stirring at 65°C for 6 hours, the reaction mixture exhibited a slight brown discoloration.

[0180] Thereafter, the reaction was terminated, and the reaction mixture was cooled to room temperature and allowed to stand overnight.

[0181] After this time, about 50 ml of the clear upper phase had separated, whereas the lower phase, which continued to have a brownish discoloration, remained turbid. 1 H analysis of these two phases revealed that the upper phase consisted primarily of ethanol and monomeric silane, while the lower phase consisted of monomeric silane and oligomeric target product in a molar ratio of approximately 1:1, along with a small amount of ethanol. Therefore, the reaction was far from complete conversion. The reaction mixture was then discarded.

[0182] Comparative Example 2: Reaction procedure not according to the invention (addition of acid (S) and water in reverse order):

[0183] The same apparatus, formulations, and amounts of the same chemicals as in Example 1 of the present invention were used. However, water and trimethylpentyltriethoxysilane were first mixed with vigorous stirring, resulting in a turbid mixture. The mixture was then heated to 65°C, and 25% hydrochloric acid was metered in at this temperature over the course of 20 minutes with vigorous stirring. Heating of the reaction mixture was not noticeable. After stirring at 65°C for 6 hours, the reaction mixture exhibited a slight brown discoloration.

[0184] Thereafter, the reaction was terminated, and the reaction mixture was cooled to room temperature and allowed to stand overnight.

[0185] On the second day, the results were clearly substantially the same as those of Comparative Example 1.

[0186] Comparative Example 3: Non-inventive process reaction (using a basic catalyst instead of an acidic catalyst):

[0187] The apparatus used is the same as that in Example 1 of the present invention.

[0188] Chemicals used in reaction steps (R1) and (R2):

[0189] 600.0 g of 1,4,4-trimethylpentyltriethoxysilane (2.17 mol)

[0190] 3.1 g of a 30 wt% sodium methoxide solution in methanol (0.017 mol NaOCH3)

[0191] 42.5 g of water (2.36 mol)

[0192] program

[0193] 600.0 g of 1,4,4-trimethylpentyltriethoxysilane was introduced and heated to 65°C. At this temperature, 3.1 g of a 30 wt% solution of sodium methoxide in methanol was metered in at a uniform rate over the course of 20 minutes with vigorous stirring. The reaction mixture remained clear, but after only 5 minutes from the start of the addition, it began to develop a brown color. After the addition was complete, stirring was continued at 65°C for 10 minutes, during which time the brown color became more intense.

[0194] Thereafter, 42.5 g of water were metered in over the course of 30 minutes, while maintaining the temperature. Immediately after the start of the metered addition, the reaction mixture became noticeably turbid. A very slightly exothermic reaction began, with the reaction temperature rising by 2-4°C to 67-69°C. Cooling of the reaction mixture was not required. After the metered addition was complete, the previously dark brown and still turbid reaction mixture was stirred at 65°C for a further 5 hours.

[0195] Thereafter, the reaction was terminated, and the reaction mixture was cooled to room temperature and allowed to stand overnight.

[0196] After this time, about 200 ml of the upper phase with a slight brown discoloration had separated, while the lower phase with an intense brown discoloration was still turbid. 1 H analysis of the two phases showed that the upper phase consisted essentially of ethanol and monomeric silane, while the lower phase consisted of monomeric silane and oligomeric target product in a molar ratio of approximately 1:2, as well as a small amount of ethanol. The reaction mixture was then discarded.

[0197] Comparative Example 4: Non-inventive process reaction (using a basic catalyst instead of an acidic catalyst):

[0198] The procedure was as in Comparative Example 3, wherein 9.0 g (0.059 mol) of DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) was used instead of 3.1 g of a 30 wt% solution of sodium methoxide in methanol (0.017 mol NaOCH 3 ) as the basic catalyst.

[0199] Here again, the reaction mixture remained clear during the catalyst addition. There was no discoloration. However, upon starting the water addition, there was also an immediate clouding of the reaction mixture. However, there was no discoloration. No exothermic heating of the reaction mixture was observed.

[0200] After termination of the reaction, the reaction mixture was still turbid after a subsequent stirring time of 5 hours. Only a very small amount of the upper phase separated overnight. 1 H analysis showed that significantly more than half of the alkoxysilane used remained unchanged. The batch was then discarded.

[0201] Example 4 of the present invention: The present invention program of a particularly preferred embodiment (AF2)

[0202] The apparatus used is the same as that in Example 1 of the present invention.

[0203] Chemicals used in reaction steps (R1) and (R2):

[0204] 600.0 g of 1,4,4-trimethylpentyltriethoxysilane (2.17 mol)

[0205] 2.5 g of 25 wt% aqueous hydrochloric acid solution (0.017 mol HCl, 0.104 mol H2O)

[0206] 46.0 g of water (2.56 mol)

[0207] program

[0208] 600.0 g of 1,4,4-trimethylpentyltriethoxysilane were introduced and heated to 65° C. At this temperature, 1.3 g of 25% aqueous HCl solution were metered in at a uniform rate over the course of 20 minutes with vigorous stirring; the reaction mixture initially became slightly turbid (two-phase system). Stirring was continued at 65° C. for 10 minutes, at which point the reaction mixture became clear again.

[0209] Thereafter, 42.0 g of water were metered in over the course of 30 minutes, while maintaining the temperature. A noticeable exothermic reaction began, and the reaction temperature rose to ~70°C. To limit the temperature to 70°C, the reaction mixture was cooled after reaching this temperature. The reaction mixture remained clear throughout. After the metering was complete, stirring was continued at 65°C for 60 minutes.

[0210] After replacing the reflux condenser with a Claisen condenser with a short column (approximately 1-2 trays), low boilers were distilled off at an oil bath temperature of 120°C and atmospheric pressure until no more distillate was produced. The liquidus temperature was continuously raised to 110°C. In this case, ~220 g of distillate were obtained. Thereafter, the pressure was reduced to 10 mbar, yielding a further ~4 g of distillate. The resulting reaction mixture had a chloride content of 43 ppm.

[0211] The mixture was then cooled to 65° C. and 0.25 g of a 50% aqueous sodium hydroxide solution (0.003 mol) was added at this temperature until the reaction mixture was glass clear, becoming slightly opaque. Immediately after the addition of the base, the reaction mixture had a pH of 4, which rose to a pH of ˜6 after 5 min of stirring and to a pH of 7 after 10 min of stirring. After the addition of the base, the reaction mixture was stirred at 65° C. for a total of 45 min.

[0212] Thereafter, low boilers were removed at an oil bath temperature of 120° C. and a pressure of 5 mbar, resulting in ˜5 g of distillate. After ˜30 min, no further distillate was obtained and the distillation was ended.

[0213] 403 g of residue were obtained in the form of a colorless liquid. The product exhibited very slight turbidity, but no appreciable amount of solids had precipitated even after 14 days of storage.

[0214] Characterization of the final product (alkyl silicone resin (A)):

[0215] The final product was a clear liquid with a viscosity of 238 mPas (measured by the method indicated in the description).

[0216] pass 1 H and 29The final product was analyzed by Si-NMR distribution to determine the amount of ethoxy groups, the distribution of Si units in the various condensation stages, the amount of silanol groups remaining in the product, and the amount of free ethanol remaining in the product. The results obtained in this case are as follows:

[0217] Ethoxy content: 13.1 wt% (based on the total weight of the final product)

[0218] Silanol content: 338ppm (calculated as O 1 / 2 H (molar mass = 9, based on the total weight of the final product)

[0219] Ethanol content: 0.11 wt% (based on the total weight of the final product)

[0220] Distribution of Si units at various condensation stages:

[0221] Si(OEt)3 unit: 0.7 mol% (monosilane)

[0222] Si(OEt)2O 1 / 2 Unit: 15.1 mol%

[0223] Si(OEt)O 2 / 2 Unit: 54.4 mol%

[0224] SiO 3 / 2 Unit: 29.8 mol%

[0225] Inventive Example 5: Inventive but non-preferred procedure for the method of the present invention.

[0226] The procedure is the same as in Example 1 of the present invention, with the only difference being the omission of the addition of sodium hydroxide (reaction step (R3)) and the neutralization of the final product (reaction step (R5)). The procedures and processes for all remaining reaction steps are as described in Example 1 of the present invention.

[0227] Characterization of the final product (alkyl silicone resin (A)):

[0228] The final product was a clear liquid with a viscosity of 125 mPas (measured by the method indicated in the description).

[0229] pass 1 H and 29 The final product was analyzed by Si-NMR distribution to determine the amount of ethoxy groups, the amount of silanol groups remaining in the product, and the amount of free ethanol remaining in the product. The results obtained in this case were as follows:

[0230] Ethoxy content: 14.3 wt% (based on the total weight of the final product)

[0231] Silanol content: 11800ppm (calculated as O 1 / 2 H (molar mass = 9, based on the total weight of the final product)

[0232] Ethanol content: 0.21 wt% (based on the total weight of the final product).

Claims

1. A process for producing an alkyl silicone resin (A) comprising at least 80 wt % of units of formula (I): R 1 a (R 2 O) b (HO) d R 3 c SiO (4-a-b-c-d) / 2 (I), in R 1 are identical or different and are monovalent, SiC-bonded, unsubstituted or substituted aliphatic hydrocarbon radicals having not more than 4 carbon atoms, R 2 are identical or different and are hydrogen or a monovalent, unsubstituted or substituted hydrocarbon radical having not more than 4 carbon atoms, R 3 are identical or different and are monovalent, SiC-bonded, unsubstituted or substituted hydrocarbon radicals having at least 5 carbon atoms, a is 0, 1, 2, or 3, b is 0, 1, 2, or 3, and c is 0, 1 or 2, provided that the sum of a+b+c is less than or equal to 3, and in at least 50% of the units of formula (I), the sum of a+b is 0 or 1, and in at least 40% of the units of formula (I), c is 1, d is 0 or 1, and in, Alkoxy R 2 The amount of O is 3-20wt%, wherein the alkylalkoxysilane (Al) of the general formula (II) is reacted in the first reaction step (R1) with a pK of not more than 5 a pure acid (S), or with at least 5 wt% of a compound having a pK not greater than 5 a An aqueous solution of an acid (S) or a mixture of a halogenated silane compound (A2) of formula (III) R 1 a R 3 c Si(OR 2 ) (4-a-c) (II), Among them, R 1 、R 2 、R 3 , a and c are the same as those defined in general formula (I), R 1 a R 3 c Si(X) (4-a-c) (III), Where X is a halogen atom and R 1 、R 3 , a and c are the same as those defined in general formula (I), and subsequently adding water in at least one further reaction step (R2), wherein reaction steps (R1) and (R2) are followed by a further reaction step (R3) in which a base (B) is added in an amount greater than the amount of base (B) required to completely neutralize the amount of acid (S) present in the reaction mixture at the time of addition of the base (B) or greater than the amount of base (B) required to completely neutralize the amount of hydrogen halide released from the halosilane compound (A2) and present at the time of addition of the base (B).

2. The method according to claim 1, wherein R 1 Selected from methyl and ethyl groups.

3. The method according to claim 1 or 2, wherein: R 2 Selected from methyl and ethyl groups.

4. The method according to claim 1 or 2, wherein: All groups R 3 At least 90 mol % of the alkyl groups are alkyl groups having 8 to 16 carbon atoms.

5. The method according to claim 1 or 2, wherein: The alkyl silicone resin (A) has at least 40 units of the formula (I) in which a is 0 and c is 1, based in each case on the total number of units of the formula (I).

6. The method according to claim 1 or 2, wherein: The base (B) is selected from hydroxides or carbonates of alkali metals or alkaline earth metals, and alkali metal alkoxides.

7. The method according to claim 1 or 2, wherein: In a further process step (R4), the alcohol R released during the process is 2 The OH is partially or completely distilled off.

8. The method according to claim 1 or 2, wherein: The salts obtained in reaction step (R3) by addition of the base and optionally also salts obtained in one or more further neutralization steps (R5) are removed by filtration step (R6).

9. The method according to claim 1 or 2, wherein: In the reaction step (R1), a halosilane compound (A2) or a hydrohalic acid is used, and during or after the reaction step (R2), at least 30% of the alcohol R released in the preceding reaction step is converted to 2 OH is distilled off, the hydrogen halide present in the reaction mixture is also at least partially distilled off, and then the base (B) is added in reaction step (R3), the amount of base (B) added being greater than the amount required to completely neutralize the amount of hydrohalic acid remaining in the reaction mixture.

10. The method according to claim 9, wherein: During or after reaction step (R2), at least 60% of the amount of alcohol R released in the preceding reaction step is converted to 2 OH was removed by distillation.

11. The method according to claim 9, wherein In a further distillation step (R4), the alcohol R still present in the reaction mixture after reaction step (R3) is distilled to 2 OH is partially or completely removed.

12. The method according to claim 9, wherein In the reaction step (R1), an aqueous hydrochloric acid solution having an acid concentration of at least 5 wt% or a chlorosilane compound (A2) which is a compound of formula (III) in which X is a chlorine atom is used.

13. The method according to claim 1 or 2, wherein: The alkyl silicone resin (A) produced has an alcohol content of not more than 2 wt %.