Process for preparing polyorganosiloxane copolymers

Abstract

A process useful for preparing a poly (dimethyl / methylvinyl) siloxane copolymer is provided. The method includes the use of Raman spectroscopy.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application Serial No. 63 / 352,260, filed on June 15, 2022. U.S. Provisional Patent Application Serial No. 63 / 352,260 is hereby incorporated by reference. Technical Field

[0003] The present invention discloses a method for preparing a polyorganosiloxane copolymer. More specifically, the method produces a polyorganosiloxane copolymer having the formula R'RSiO 2 / 2 Unit (D Vi A copolymer having a desired sequence distribution of 1,2-dimethyl-1,2-dihydrocarbyl units), wherein each R is a monovalent hydrocarbon group or a halogenated hydrocarbon group and each R' is an alkenyl group. Background Art

[0004] U.S. Patent No. 3,183,209 discloses vinyl-containing organopolysiloxane and a method for producing the same. Vinyl-containing organopolysiloxane can be prepared by heating decamethyltetrasiloxane and cyclic siloxanes, namely methylvinylcyclosiloxane, octamethylcyclotetrasiloxane and octaphenylcyclotetrasiloxane, in the presence of potassium dimethylsilanol.

[0005] Methylvinylsiloxane copolymers have been characterized by NMR, but the disadvantage is that it is difficult, expensive and impractical to use NMR techniques to analyze the reaction mixture used to produce methylvinylsiloxane copolymers on a commercial scale in real time. Therefore, previous methods may have the disadvantage of low productivity because it may be desirable to stop the reaction when the desired product structure is reached or very shortly thereafter to minimize the processing time. However, the time to reach the desired product structure may vary from batch to batch for a variety of reasons, including the specific siloxane selected as the reactant, and the variability of the process conditions such as the selected temperature. Therefore, the time required to obtain the desired product will vary from batch to batch. Summary of the invention

[0006] The present invention provides a method for preparing a polyorganosiloxane copolymer. The method comprises:

[0007] 1) combining starting materials, the starting materials comprising

[0008] A) Formula (R2SiO 2 / 2 ) is derived from siloxane units,

[0009] B) Formula (RR'SiO 2 / 2 ) is derived from siloxane units,

[0010] wherein each R is independently selected from an alkyl group and a haloalkyl group, and R'

[0011] represents an alkenyl group, and

[0012] C) a base catalyst,

[0013] Thus forming a mixture;

[0014] 2) stirring the mixture at a temperature sufficient to form a reaction mixture comprising the copolymer via an equilibrium reaction;

[0015] 3) using Raman spectroscopy to monitor a spectral region including a characteristic Raman band corresponding to the decoupled (RR'SiO 2 / 2 ) unit concentration and coupled (RR'SiO 2 / 2 ) units, wherein R and R' are as described above;

[0016] 4) Stopping the equilibrium reaction when a target value associated with the characteristic Raman band is reached. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The integrated peak area of ​​the decoupled -OSiMeVi- portion over time is shown for three different samples having different -OSiMeVi- contents in weight percent generated according to Reference Example C. Note that while peak area is used in all examples, other ways of quantifying peak intensity, such as peak height, may also be used.

[0018] Figure 2 The spectral changes that can be observed based on in situ Raman reaction spectroscopy are demonstrated, as well as how the peak areas of coupled and decoupled-OSiViMe- species can be used to track the progress of the reaction.

[0019] Figure 3 Comparison of the in situ Raman results with the off-line NMR analysis is shown. Remarkable agreement is observed. DETAILED DESCRIPTION

[0020] Step 1) of the method described herein comprises combining starting materials comprising: A) a formula (R2SiO 2 / 2 ) of the siloxane unit source, B) of the formula (RR'SiO 2 / 2 ) a source of siloxane units, wherein each R is independently selected from an alkyl group and a haloalkyl group, and C) a base catalyst, thereby forming a mixture.

[0021] The starting materials A) and B) may be one or more polyorganosiloxanes comprising the unit formula: (R3SiO 1 / 2 ) t (R2R'SiO 1 / 2 ) u (R2SiO2 / 2 ) v (RR'SiO 2 / 2 ) w (RSiO 3 / 2 ) x (R'SiO 3 / 2 ) y (SiO 4 / 2 ) z , wherein the subscripts t, u, v, w, x, y and z represent the amount of each unit and have an average value such that t≥0, u≥0, v≥1, w≥1, x≥0, y≥0, z≥0, provided that the amount (v+w)≥3, the amount (x+y+z) is from 0 to a value sufficient to provide up to 20 mol% of siloxane units in the molecule; the amount (t+u+v+w)≥3. Alternatively, (t+u+v+w) may have a value greater than or equal to 3, alternatively 3 to 2,000; alternatively 3 to 1,000; alternatively 3 to 500; alternatively 3 to 300; and alternatively 3 to 200. In this unit formula, each R is independently selected from an alkyl group and a haloalkyl group. Alternatively, when the polyorganosiloxane is linear or cyclic, the amount (x+y+z)=0.

[0022] Suitable alkyl groups for R are exemplified by methyl, ethyl, propyl (including n-propyl and / or isopropyl), butyl (including n-butyl, tert-butyl, sec-butyl and / or isobutyl), pentyl (including cyclopentyl, n-pentyl and branched isomers with 5 carbon atoms), hexyl (including cyclohexyl, n-hexyl and branched isomers with 6 carbon atoms), heptyl (including cycloheptyl, n-heptyl and branched isomers with 7 carbon atoms), octyl (including cyclooctyl, n-octyl and branched isomers with 8 carbon atoms), nonyl (including cyclononyl, n-nonyl and branched isomers with 9 carbon atoms) and decyl (including cyclodecyl, n-decyl and branched isomers with 10 carbon atoms). Suitable haloalkyl groups for R are alkyl groups (such as those described above) in which one or more hydrogen atoms bonded to a carbon atom have been formally replaced by a halogen atom. The halogenated alkyl group includes a fluorinated alkyl group such as trifluoromethyl (CF3), fluoromethyl, trifluoroethyl, 2-fluoropropyl, 3,3,3-trifluoropropyl, 4,4,4-trifluorobutyl, 4,4,4,3,3-pentafluorobutyl, 5,5,5,4,4,3,3-heptafluoropentyl, 6,6,6,5,5,4,4,3,3-nonafluorohexyl, 8,8,8,7,7-pentafluorooctyl, 2,2-difluorocyclopropyl, 2,3-difluorocyclobutyl, 3,4-difluorocyclohexyl and 3,4-difluoro-5-methylcycloheptyl; and a chlorinated alkyl group such as chloromethyl, 3-chloropropyl, 2,2-dichlorocyclopropyl and 2,3-dichlorocyclopentyl. Alternatively, each R can be selected from methyl, ethyl, propyl or butyl; Alternatively methyl or ethyl; And alternatively, each R can be methyl.

[0023] In the above formula, each R' is an independently selected alkenyl group. Suitable alkenyl groups for R' may be selected from vinyl, allyl, and hexenyl; alternatively vinyl and hexenyl; and alternatively vinyl.

[0024] When the polyorganosiloxane has (R2SiO 2 / 2 ) unit and (RR'SiO 2 / 2 ) units, the starting materials A) and B) can be the same molecule. Alternatively, the starting materials A) and B) can be different molecules.

[0025] For example, the starting material A) may be selected from: A1) having a unit formula (R2SiO 2 / 2 ) c Cyclic polyorganosiloxane, wherein 3≤c≤12; A2) contains a unit formula (R3SiO 1 / 2 ) a (R2R'SiO 1 / 2 ) d (R2SiO 2 / 2 ) bA linear polyorganosiloxane wherein the amount (a+d) = 2, and 3≤b≤200; and A3) a combination of A1) and A2). In the unit formulas of A1) and A2), R and R' are as described above. Alternatively, in the starting material A1), the subscript c may be greater than or equal to 3, alternatively 3≤c≤9, alternatively 3≤c≤6, alternatively 4≤c≤6. Alternatively, in the starting material A2), the subscript d may be 0. Cyclic polydiorganosiloxanes suitable for use as starting material A1) are known in the art and commercially available. For example, examples of dimethylcyclosiloxanes octaorganocyclotetrasiloxanes such as 2,2,4,4,6,6,8,8-octamethylcyclotetrasiloxane; decaorganocyclopentasiloxanes such as 2,2,4,4,6,6,8,8-decamethylcyclopentasiloxane; and dodecaorganocyclohexasiloxanes such as 2,2,4,4,6,6,8,8,10,10-dodecamethylcyclohexasiloxane are known in the art and are commercially available from various sources, such as Dow Silicones Corporation, Midland, Michigan, USA; Gelest, Inc., Morrisville, Pennsylvania, USA; Sigma-Aldrich, Inc., St. Louis, Missouri, USA. Suitable linear polyorganosiloxanes suitable for use as starting material A2) include trimethylsiloxy-terminated polydimethylsiloxanes, which are also known in the art and commercially available from the same sources listed above. Trimethylsiloxy-terminated polydimethylsiloxanes with viscosities of 5 cSt, 10 cSt, 50 cSt, 500 cSt and 1,000 cSt are commercially available from Dow Silicones, Midland, Michigan, USA. Viscosity can be measured at 0.1 RPM to 50 RPM on a Brookfield DV-III cone and plate viscometer with a #CP-52 spindle at 25°C. Those skilled in the art will recognize that the rotation rate decreases as viscosity increases, and will be able to select an appropriate rotation rate when measuring viscosity using this test method. Alternatively, suitable dimethylvinyl-siloxy-terminated polydimethylsiloxanes can be used as starting material A2), and these are also known in the art and can be purchased under the trade name: DMS- V00 、DMS- V05 、DMS- V21 and DMS- V31 It is commercially available from various suppliers including Gilster Corp. Alternatively, the starting material A) may be free of silicon-bonded alkenyl groups.

[0026] The starting material B) is alkenyl-functional and can be selected from: B1) having the unit formula (RR'SiO 2 / 2 ) c Cyclic polyorganosiloxane, wherein 3≤c≤12; B2) has a unit formula (R3SiO 1 / 2 ) a (R2R'SiO 1 / 2 ) d (RR'SiO 2 / 2 ) e A linear polyorganosiloxane wherein the amount (a+d) = 2, and 3≤e≤200; and B3) a combination of B1) and B2). In the unit formulas of B1) and B2), R and R' are as described above. Alternatively, in the unit formula of B1), the subscript c may be greater than or equal to 3, alternatively 3≤c≤9, alternatively 3≤c≤6, and alternatively 4≤c≤6. Alternatively, in the unit formula of B2), the subscript d may be 0.

[0027] Cyclic polyorganosiloxanes suitable for use as starting material B1) are known in the art and are commercially available. Examples of cyclic alkenyl-functional polydiorganosiloxanes include 2,4,6-trimethyl-2,4,6-trivinyl-cyclotrisiloxane; 2,4,6,8-tetramethyl-2,4,6,8-tetravinyl-cyclotetrasiloxane; 2,4,6,8,10-pentamethyl-2,4,6,8,10-pentavinyl-cyclopentasiloxane; and 2,4,6,8,10,12-hexamethyl-2,4,6,8,10,12-hexavinyl-cyclohexasiloxane. These cyclic alkenyl-functional polydiorganosiloxanes are known in the art and are commercially available from, for example, Sigma-Aldrich, St. Louis, Missouri, USA; Milliken (Spartanburg, South Carolina, USA); and other suppliers.

[0028] The starting material (B2) may comprise an alkenyl functional polydiorganosiloxane such as i) bisdimethylvinylsiloxy terminated poly(dimethylsiloxane / methylvinylsiloxane), ii) bisdimethylvinylsiloxy terminated polymethylvinylsiloxane, iii) bistrimethylsiloxy terminated poly(dimethylsiloxane / methylvinylsiloxane), iv) bistrimethylsiloxy terminated polymethylvinylsiloxane), v) bisdimethylhexenylsiloxy terminated poly(dimethylsiloxane / methylvinylsiloxane), iii) bistrimethylsiloxy terminated poly(dimethylsiloxane / methylvinylsiloxane), iv) bistrimethylsiloxy terminated polymethylvinylsiloxane, iv) bistrimethylsiloxy terminated poly(methylvinylsiloxane), iv) bisdimethylhexenylsiloxy terminated poly(dimethylsiloxane / methylvinylsiloxane), ...methylvinylsiloxane), iv) bisdimethylhexenylsiloxy terminated poly( The invention also includes poly(dimethylsiloxane / methylhexenylsiloxane) terminated with bis(dimethylsiloxane / methylhexenylsiloxane), vi) poly(dimethylsiloxane / methylhexenylsiloxane) terminated with bis(dimethylsiloxane / methylhexenylsiloxane), vii) poly(dimethylsiloxane / methylhexenylsiloxane) terminated with bis(trimethylsiloxy)siloxy), viii) poly(dimethylsiloxane / methylhexenylsiloxane) terminated with bis(trimethylsiloxy)siloxy, ix) poly(dimethylsiloxane / methylhexenylsiloxane) terminated with bis(dimethylvinylsiloxy), and x) combinations of two or more thereof.

[0029] Methods for preparing the linear alkenyl functional polydiorganosiloxanes described above for starting material (B2), such as hydrolysis and condensation of the corresponding organohalosilanes and oligomers or equilibration of cyclic polydiorganosiloxanes with hydroxyl functional polydiorganosiloxanes, are known in the art, see, for example, U.S. Pat. Nos. 4,772,515 and 5,317,072, which disclose the preparation of linear polydiorganosiloxanes having alkenyl groups. Examples of linear polydiorganosiloxanes having alkenyl groups are available from, for example, Gilster, Inc. of Morrisville, Pennsylvania, USA, under the trade name VDT- 123 、VDT- 127 、VDT- 131 、VDT- 431 、VDT- 731 and VDV- 0131 Commercially available.

[0030] Starting material C) is a base catalyst suitable for catalyzing the equilibrium reaction in the method described herein. The catalyst can be homogeneous or heterogeneous. Suitable catalysts include alkali metal hydroxides such as potassium hydroxide and sodium hydroxide; tetrabutylphosphonium hydroxide; tetramethylammonium hydroxide, phosphazene bases and silicon alkoxides such as potassium trimethylsiliconate and ammonium tetramethylsiliconate. Catalysts suitable for use as starting material C) are known in the art, such as base catalysts disclosed in U.S. Pat. No. 3,183,209, U.S. Pat. No. 4,772,515 or U.S. Pat. No. 6,448,196, and can be commercially obtained from various suppliers such as Millipore Sigma, St. Louis, Missouri, USA.

[0031] The amount of starting material C), i.e., catalyst, is sufficient to catalyze the equilibrium reaction. The exact amount of C) catalyst depends on various factors, such as whether the catalyst is homogeneous or heterogeneous and whether the process is carried out batchwise or in a continuous manner, however, the amount of catalyst may be >0% to 10% by weight, alternatively >0% to 5%, and alternatively >0% to 0.1% by weight; this is based on the combined weight of the starting materials A), B), C) and D) used in the process. Alternatively, the amount of heterogeneous catalyst used in a batch process may be >0% to 5%, alternatively >0% to 2%, alternatively 0.5% to 5%, alternatively 1% to 5%, and alternatively 1% to 2%, based on the combined weight of the starting materials A), B), C) and D) used in step 1) of the process. Alternatively, when the process is carried out batchwise with a homogeneous catalyst, the amount of catalyst may be >0% to 1%. Alternatively, when the process is carried out continuously, the amount of catalyst may be different. For example, a heterogeneous catalyst may be used in a packed bed in a continuous process, where the amount of catalyst will depend on the size of the reactor.

[0032] The starting materials used in the method may be free of water. Without wishing to be bound by theory, it is believed that water can inhibit C) the base catalyst. "Free of water" means that the starting materials are free of water, alternatively contain an undetectable amount of water, and alternatively contain water in an amount insufficient to inhibit C) the base catalyst. The starting materials used in the method may also optionally include one or more additional starting materials. For example, the additional starting materials may be selected from D) an end-capping agent, E) a quenching agent, or both.

[0033] The capping agent is different from the starting materials A) and B) and may comprise units of the formula (R3SiO 1 / 2 ) e (R2R'SiO 1 / 2 ) f (R2SiO 2 / 2 ) g (RR'SiO 2 / 2 ) h , wherein R and R' are as described above, subscript e is 0, 1 or 2; subscript f is 0, 1 or 2; the amount (e+f) = 2; subscript g ≥ 0, subscript h ≥ 0; and 0 ≤ (g+h) ≤ 3. Alternatively, the amount (c+d) may be from 0 to 2, and alternatively from 0 to 1. Capping agents are known in the art and are commercially available. Examples of capping agents may include 1,3-divinyl-1,1,3,3-tetramethyldisiloxane; 1,1,1,3,3-pentamethyl-3-vinyl-disiloxane; 1,1,1,3,5,5,5-heptamethyl-3-vinyl-trisiloxane, all of which are commercially available, for example, from Gayles, Inc., Morrisville, Pennsylvania, USA, or Sigma-Aldrich, Inc., St. Louis, Missouri, USA.

[0034] The end-capping agent is optional. However, for example, when using cyclic starting materials A1) and B1) in the method, the end-capping agent can be used. According to the combined weight of starting materials A), B), C) and D), the end-capping agent can be used in an amount of 0% to 44.5%, alternatively 0% to 40%, alternatively 0% to 30%, alternatively 0% to 25%. The balance of the starting materials used in the method can be starting materials A) and B). Alternatively, according to the combined weight of starting materials A), B), C) and D) used in the method, starting materials A) and B) can account for 45.5% by weight to <100% by weight, alternatively 50% to <100%, alternatively 60% to <100%, and alternatively 75% to <100%.

[0035] Steps 1) and 2) of the method can be performed in any convenient manner using conventional equipment. For example, the starting materials can be combined in a jacketed container equipped with an agitator. The starting materials can be added to the container in any order. Step 1) and step 2) can be performed sequentially or simultaneously. When the equilibrium reaction occurs, step 2) can be performed by mixing with an agitator while controlling the temperature in the container at 100°C to 160°C, alternatively 140°C to 150°C.

[0036] The equilibrium reactions described herein are illustrated by the following exemplary reaction schemes:

[0037]

[0038] Wherein R and R' are as described above, subscript m is 1 to 10, subscript n is 1 to 10, subscript o is 0 to 3, and the amount (p+q) ≥ 3, mainly 3 to 9, and the amount (r+s) = 10 to 1,000. Alternatively, subscript s may be 10 to 500, alternatively 30 to 250, and subscript r may be 3 to 70. Alternatively, each R may be methyl, subscript m may have an average value of 2, subscript n may have an average value of 2, and subscript o may be 0. In the above reaction scheme, the reaction includes a balance of ≡Si-O-Si≡ bonds from one molecule to another, including the opening of the cyclic siloxane and end-capping by the end-capping agent shown above. It may be desirable to produce a fully balanced product.

[0039] Using the above reaction scheme, in step 2), a polyorganosiloxane copolymer product and mixed cyclic byproducts are formed. The copolymer comprises a polyorganosiloxane having the formula (R2SiO 2 / 2 ) and a D unit having the formula (RR'SiO 2 / 2 ) Vi Without wishing to be bound by theory, it is believed that during step 2), the copolymer has a block distribution of difunctional units when it is first formed, i.e. D ViAs the equilibrium reaction proceeds, D and D Vi The position of the units will change to a more random sequence in the copolymer backbone. Raman spectroscopy can be used to determine the molecular mass corresponding to the coupled D Vi Unit and Decoupling D Vi The characteristic Raman band (peak on the spectrum) of the unit. Coupling refers to the D Vi Unit with another D Vi Decoupling refers to the D Vi Unit does not communicate with another D Vi The units are adjacent.

[0040] The present inventors have found that Raman spectroscopy can be used to monitor the reaction mixture in real time in step 3) of the above method. In addition, Raman spectroscopy can be used to monitor the reaction mixture in situ. The present inventors surprisingly found that Raman spectroscopy can detect D and D in the main chain of the polyorganosiloxane copolymer. Vi In addition, Raman spectroscopy as described herein can be used to modify the sequence of D:D Vi The copolymer has a D:D ratio of at least 1:1, alternatively at least 1.5:1, and alternatively at least 2:1. Vi can be at most 30:1, alternatively at most 15:1, alternatively at most 10:1, alternatively at most 5:1, and alternatively at most 3:1. Alternatively, the Raman spectroscopy described herein can be used for D:D Vi Copolymers having a ratio of 1:1 to 30:1, alternatively 1:1.5 to 1:2.5, and alternatively 1:2 to 1:3. Alternatively, the Raman spectroscopy described herein can be used for D:D Vi Copolymers in ratios of 100:1 to 1:100, alternatively 75:1 to 1:75, alternatively 50:1 to 1:50, alternatively 30:1 to 1:30, alternatively 5:1 to 1:5, alternatively 3:1 to 1:3, alternatively 2.5:1 to 1:2.5, alternatively 2:1 to 1:2, and alternatively 1.5:1 to 1:1.5.

[0041] When the equilibrium reaction is carried out, the intensity of the characteristic Raman band (for example, the peak height and / or peak area on the spectrum measured by Raman spectroscopy) can be measured after a time interval. The peak area and peak height of the decoupled Si-R' Raman band increase with the increase of reaction time, while the peak area and peak height of the coupled Si-R' Raman band decrease with the increase of reaction time. U.S. Patent Application 2004 / 0198927 discloses a device for measuring the intensity of the characteristic Raman band (to obtain peak height and peak area) using Raman spectroscopy. These Raman features can be used to set a target value for when to stop the reaction to optimize the characteristics of the polyorganosiloxane copolymer and / or optimize the reaction batch time. The target value can be set based on the decoupled Si-R' peak area, the decoupled Si-R' peak height, the coupled Si-R' peak area and / or the coupled Si-R' peak height. When the value of any one or more of these features reaches the target value, the reaction can be controlled by stopping the reaction. Those skilled in the art can set the target value for each of these parameters to optimize application performance while minimizing batch time. The target value may also be set based on the rate of change of any of these parameters. For example, as the reaction proceeds, the decoupled Si-R' peak area increases until it reaches a maximum value, and then as follows, for example Figure 1 and Figure 3 Flattened as shown in .

[0042] The rate of change of the intensity of each characteristic Raman band in each time interval can be calculated. When the rate of change is close to 0, this indicates that the copolymer is completely balanced (with D and D ViThe random distribution of units). Therefore, when a random copolymer is required, the target value can be set to a value of 0% to 10% of the maximum absolute value of the rate of change within a selected time interval, such as a 15-minute average value that can be measured during the equilibrium reaction for terminating the reaction in step 4). Alternatively, the target value can also be set to stop the reaction when the rate of change reaches a predetermined value of any one of the features of decoupled Si-R' peak area, decoupled Si-R' peak height, coupled Si-R' peak area or coupled Si-R' peak height, as described and illustrated in the embodiments herein below. Alternatively, the target value can also be set to stop the reaction when the decoupled Si-R' peak height or the decoupled Si-R' peak area reaches its maximum value or 90% to 100% of its maximum value. Alternatively, the target value can be set to stop the reaction when the coupled Si-R' peak height or the coupled Si-R' peak area reaches its minimum value or 0% to 10% of its minimum value. The target value can be set and / or determined when the target value has been reached using one or more of the features described herein. Alternatively, mathematical transformations of peak height, peak area or rate of change data can be used to smooth the resulting data, including but not limited to averaging multiple instrument readings or fitting the data to a mathematical equation (such as an exponential decay or logistic function). Chemometric analysis such as classical least squares (CLS), partial least squares (PLS), principal component regression (PCR) can also be used to replace the above univariate analysis to set the target.

[0043] Stopping the reaction in step 4) can be carried out by any convenient means, such as cooling and / or filtering to remove the catalyst (when a heterogeneous catalyst is used) or neutralizing with E) a quenching agent (when a homogeneous catalyst is used) to form a salt, which can then be removed by filtering in batch or continuous mode. Quenching agents are known in the art and are exemplified by acetic acid, silyl phosphates, silyl phosphonates and carbon dioxide.

[0044] The methods described herein may also optionally include one or more additional steps. For example, the method may also include step 5): recovering the polyorganosiloxane copolymer. During the equilibrium reaction, byproducts (such as mixed cyclics described above in the exemplary reaction scheme) may be formed and / or unreacted starting materials A) and / or B may be present in the reaction mixture. Recovery may be performed, for example, by any convenient means, such as stripping and / or distillation to remove unreacted starting materials and / or byproducts from the polyorganosiloxane copolymer.

[0045] The method may further optionally include step 6): repeating the steps including 1) to 4) (and optionally 5) while reusing the catalyst in step 1) (when a heterogeneous catalyst is used).

[0046] The methods described herein can produce polyorganosiloxane copolymers comprising the following unit formula: (R3SiO 1 / 2) tt (R2R'SiO 1 / 2 ) uu (R2SiO 2 / 2 ) vv (RR'SiO 2 / 2 ) ww (RSiO 3 / 2 ) xx (R'SiO 3 / 2 ) yy (SiO 4 / 2 ) z z , wherein the subscripts tt, uu, vv, ww, xx, yy and zz represent the average number of each unit in the copolymer, and the subscripts tt≥0, uu≥0, vv≥1, ww≥1, xx≥0, yy≥0, zz≥0, provided that the amount (vv+ww)≥3, the amount (xx+yy+zz) is from 0 to a value sufficient to provide up to 20 mol% of siloxane units in the copolymer molecule; the amount (tt+uu+vv+ww)≥3. Alternatively, the amount (tt+uu+vv+ww) may be greater than or equal to 5. Alternatively, (tt+uu+vv+ww) may have a value of 5 to 2,000; alternatively 5 to 1,000; alternatively 10 to 500; alternatively 25 to 300; and alternatively 50 to 200. The copolymer differs from the starting materials (A) and (B) in at least one property, such as molecular weight, (R2SiO 2 / 2 ) and (RR'SiO 2 / 2 ) units and the formula (R2SiO 2 / 2 ) and the formula (RR'SiO 2 / 2 The molar ratio of the units (D:D Vi The copolymer also contains D and D Vi Unit. D:D Vi The ratio may be 100:1 to 1:100, alternatively 75:1 to 1:75; alternatively 50:1 to 1:50; alternatively 30:1 to 1:30; alternatively 5:1 to 1:5; alternatively 3:1 to 1:3; alternatively 2.5:1 to 1:2.5; alternatively 2:1 to 1:2; and alternatively 1.5:1 to 1:1.5; alternatively 1:1 to 30:1; alternatively 1:1.5 to 1:2.5; alternatively 1:2 to 1:3. Alternatively, the copolymers prepared by the methods described herein may be linear, and when the subscripts xx=0, yy=0, and zz=0, the copolymers may have the unit formula (R3SiO 1 / 2 ) tt (R2R'SiO 1 / 2 ) uu (R2SiO 2 / 2 ) vv (RR'SiO2 / 2 ) ww , subscript tt is 0, 1 or 2; subscript uu is 0, 1 or 2; the amount (tt+uu)=2; subscript vv>1, subscript ww>1, and wherein subscripts vv and ww have such that D:D Vi The ratios are the values ​​described above.

[0047] Example

[0048] The following examples are intended to illustrate the invention to those skilled in the art and should not be construed as limiting the scope of the invention set forth in the claims. The reactants and other starting materials used in the examples are shown in Table 1 below. As used in the following examples, "calculated" refers to the D:D of the copolymer calculated based on the amount of each starting material used. Vi and DP.

[0049] Table 1 - Starting Materials

[0050]

[0051]

[0052] In Table 1, DSC refers to Dow Silicones Corporation, Midland, Michigan, USA, and TDCC refers to The Dow Chemical Company, Midland, Michigan, USA.

[0053] Reference Example A - Raman spectroscopy

[0054] The reaction progress was monitored by Raman spectroscopy using the following equipment and setup: BWTek i-Raman Pro; Probe: Immersion Optics: Kaiser Optical Systems, Inc. 0.5" ODx 10" L Hastelloy C-276 shaft and gold sealed sapphire lens and 785 nm excitation. Raman cutoff 150 cm -1 . Laser fiber 105um core FC / PC terminated. Raman fiber 300um core FC / PC terminated. Fiber length 1.5m. Spectra were collected with 2 averages using 10 second exposure time. Spectra were then processed to determine the peak area trend lines for the coupled and decoupled -OSiMeVi- parts.

[0055] Reference Example B - Copolymerization Equipment

[0056] A 500 mL two-part batch reactor was used to prepare poly(dimethyl / methylvinyl)siloxane copolymers. The top (flange) portion of the reactor had 3×29 / 42 ports in line, 2×1 / 4" Ace threaded ports and a 3 / 8" Ace threaded port on one side and a 24 / 40 port on the other side. The middle 29 / 42 port had a stirring shaft connected to an overhead stirrer with a 3-blade glass impeller. One 29 / 42 port had a Dean Stark water trap connected to a condenser connected to a chiller running a Syltherm XLT at 10°C. The condenser was connected to a nitrogen inlet via a T that could purge the reaction headspace or place it under a nitrogen blanket. The nitrogen line was discharged through a mineral oil bubbler. The other 29 / 42 contained a sampling port with a Teflon tube extending into the reactor. The 3 / 8" Ace thread is used to insert the Raman probe for in situ analysis and for the 1 / 4" port, one contains the glass thermowell and thermocouple and the other contains the nitrogen inlet. The 24 / 40 neck contains the Raman probe connected via a rubber septum. TM A friction-teflon-coated O-ring seals the bottom reactor section. This is clamped in place using a compression clamp and secured with an insulated C-clamp. A heating mantle with a thermocouple in it is placed over the bottom of the reactor and secured in place with a ring clamp and a lab jack.

[0057] Reference Example C - Copolymerization Procedure

[0058] Copolymerization of cyclic reactants was carried out according to the following reaction scheme:

[0059]

[0060] A 500 mL glass reactor equipped with an overhead stirrer with a glass impeller, a thermocouple, a 1 / 8" Teflon sampling tube with a three-way valve, a Dean-Stark trap with a water-cooled reflux condenser, a nitrogen purge, and a Raman spectrometer probe was used. The flask was charged with D4, V4, and a capping agent M Vi D 7.2 M Vi , and stop nitrogen purge. Start Raman spectroscopy and acquire spectra every 20 seconds. The reaction mixture is stirred at 250rpm and heated to 160°C using a heating mantle with a temperature controller. The catalyst in the amount shown in Table 2 below is added to the reaction mixture and chased with about 2mL D4. The reaction is stopped after three hours and quenched with 5.9g neutralizer (2.5 wt % in D4).

[0061] Table 2 - Copolymerization of Cyclic Reactants

[0062]

[0063] In Table 2, W represents a working example, and C represents a comparative example. Figure 1 The integrated peak area of ​​the decoupled -OSiMeVi- portion over time is shown for three different samples with different -OSiMeVi- contents in weight percent. Sample C1 is a homopolymer of V4 (at Figure 1 The homopolymer does not show any randomization since all the side groups are identical. This is shown by the 750 cm -1 It is evident that the peak area at remains constant throughout the experiment. Two additional experiments were performed with 90:10D4:V4 (sample W4, circles) and 50:50D4:V4 (samples W1 to W3, squares). Increasing the V4 content allows for more randomization along the backbone, and therefore greater normalized Raman intensity at the end of the run. The rates at which randomization reaches equilibrium are significantly different for the 90:10D4:V4 and 50:50D4:V4 samples.

[0064] Reference Example D - Copolymerization with linear reactants

[0065] The copolymerization with the chain reactants was carried out according to the following reaction scheme:

[0066]

[0067] A 500 mL glass reactor equipped with an overhead stirrer with a glass impeller, a thermocouple, a 1 / 8" Teflon sampling tube with a three-way valve, a Dean-Stark trap with a water-cooled reflux condenser, a nitrogen purge, and a Raman spectrometer probe was used. The flask was charged with 29.4 g (21.3 mmol) of MeVi homopolymer (cyclic compounds were removed before use) and 168.8 g of PDMS (243 mmol), and the nitrogen purge was discontinued. Raman spectroscopy was started, and spectra were acquired every 20 seconds. The reaction mixture was stirred at 250 rpm and heated to 160°C using a heating mantle with a temperature controller. 1.8 g (36 ppm K+) of Catalyst 2 (12 wt%) was added to the reaction mixture, chased with about 2 mL of toluene. The reaction was stopped after 4 hours and quenched with 2.16 g of 4-6085 neutralizer (2.5 wt% in D4). The data in Table 3 below show that this method can be performed with linear reactants.

[0068] Table 3 - Copolymerization with linear reactants

[0069] sample PDMS(g) MeVi homopolymer (g) Catalyst(g) Selected catalyst W8 144 50 0.04 2 W9 168 29 1.8 2

[0070] Without wishing to be bound by theory, it is believed that the benefit of the present invention is that this method can be used to select D and D in the backbone of the polyorganosiloxane copolymer produced by the method. ViThe desired degree of randomization of the units while minimizing the batch time. For example, a high peak area target value, such as ≤ 10% of the maximum 15-minute average absolute value change rate, can be selected to obtain a highly randomized copolymer. Alternatively, for example, when a copolymer with a more blocky structure is acceptable, the target value can be set to have a lower decoupled SiR' peak area (or other suitable target value) to minimize the batch time for producing the copolymer.

[0071] Industrial Applicability

[0072] Polyorganosiloxane copolymers are intermediates that can be used to synthesize various organofunctional siloxane products. In particular, polyorganosiloxane copolymers having the formula (R2SiO 2 / 2 ) and the D unit of formula (RR'SiO 2 / 2 ) Vi Such copolymers of units are useful, for example, as crosslinkable base polymers in various cure systems such as free radical and / or hydrosilylation reaction curable products.

[0073] Without wishing to be bound by theory, it is believed that the distribution of alkenyl functional groups along the polysiloxane backbone can affect the physical and chemical properties of the resulting polyorganosiloxane copolymer. For example, a block structure can have a different reactivity than a random structure. The degree of randomness can affect physical properties such as elongation, stretch or hardness in downstream applications. During equilibrium and polymerization, it is desirable to achieve a consistent sequence distribution along the polysiloxane backbone to promote consistent performance.

[0074] The polyorganosiloxane produced by the methods described herein may have a block backbone structure (e.g., DDDDD Vi D Vi D Vi D Vi DDD), where multiple D units are combined together and multiple D Vi The units are grouped together in "blocks". However, without wishing to be bound by theory, the inventors have found that D and D Vi A more random backbone structure where the units are more randomly distributed along the backbone (e.g., DDDDD Vi DDDD Vi DD Vi DDD Vi DDDDDDDD Vi ) may be desirable for certain applications, such as using these copolymers in curable silicone compositions such as hydrosilylation curable silicone elastomer compositions. In addition, the polyorganosiloxanes produced by the methods described herein may be used in conjunction with D and D ViWhen the distribution of units in the backbone is random, it takes different times (sometimes long before) to reach its target molecular weight. This can lead to different degrees of "randomness" in the siloxane backbone structure from batch to batch and affect physical properties and performance. Moreover, the degree of randomness can affect the properties of the copolymer. The methods described herein can be used to minimize batch time and maximize randomization of polyorganosiloxane copolymers by appropriately selecting the target value for stopping the reaction in the methods described herein.

[0075] Furthermore, without wishing to be bound by theory, it is believed that the Raman spectroscopy method described herein may alternatively be used to produce other polyorganosiloxane copolymers, such as those having the formula (RR"SiO 2 / 2 ) (wherein R" is an aryl group such as phenyl) instead of the formula (RR'SiO 2 / 2 ) (wherein R and R' are as described above).

[0076] Definition and usage of terms

[0077] Unless otherwise specified, all amounts, ratios and percentages are by weight. The amount of all starting materials in the composition is 100% by weight. Summary of the invention and abstract are incorporated by reference. Unless otherwise specified in the context of this specification, the articles "one", "a kind of" and "said" each refer to one (a kind) or more (multiple). Unless otherwise specified, the singular includes plural meanings. The term "comprising" and its derivative meanings, such as "having" and "containing" are used in this article with its broadest sense, meaning and covering the concepts of "including", "essentially consisting of..." and "consisting of...". Using "for example", "for example", "such as" and "including" to list exemplary examples does not mean to be limited to the listed examples. Therefore, "for example" or "such as" means "for example, but not limited to" or "such as, but not limited to" and covers other similar or equivalent examples.

[0078] The term "decoupling Vi ” and “decoupling (RR'SiO 2 / 2 )" refers to the siloxane backbone of the copolymer that is not connected to other (RR'SiO 2 / 2 ) units adjacent to each other (RR'SiO 2 / 2 ) units. For example, in the part -(R2SiO 2 / 2 )-(RR'SiO 2 / 2 )-(R2SiO 2 / 2 )-, (RR'SiO 2 / 2 ) unit is decoupling (RR'SiO 2 / 2 ). Decoupling in the copolymer main chain (RR'SiO 2 / 2) the more random the copolymer is, with the exception of completely alternating copolymer backbones, which are not favored by the equilibrium reactions described herein.

[0079] The term "coupling Vi " and " coupling (RR'SiO 2 / 2 )" refers to other (RR'SiO 2 / 2 ) units adjacent to each other (RR'SiO 2 / 2 ) units. For example, in the part -(RR'SiO 2 / 2 )-(RR'SiO 2 / 2 )-(RR'SiO 2 / 2 )-, (RR'SiO 2 / 2 The more SiR's are coupled in the copolymer, the more block characteristics it has.

[0080] It should be understood that the appended claims are not limited to the specific and particular compounds, compositions or methods described in the detailed description, which may vary between specific embodiments falling within the scope of the appended claims. With respect to any Markush group used herein to describe specific features or aspects of various embodiments, different, special and / or unexpected results can be obtained from each member of each Markush group independent of all other Markush members. Each member of the Markush group can be relied upon individually and / or in combination and provides sufficient support for specific embodiments within the scope of the appended claims.

[0081] Any range and sub-range relied upon in describing the various embodiments of the present invention falls within the scope of the appended claims independently and collectively, and should be understood to describe and contemplate all ranges including the following: all and / or part of the values ​​therein, even if these values ​​are not explicitly stated herein. It will be readily appreciated by those skilled in the art that the enumerated ranges and sub-ranges fully describe the various embodiments of the present invention and enable them, and such ranges and sub-ranges can be further depicted as related halves, thirds, quarters, fifths, etc. As just one example, the range of "20 to 110" can be further depicted as the lower third (i.e., 20 to 49), the middle third (i.e., 50 to 79), and the upper third (i.e., 80 to 110), which are individually and collectively within the scope of the appended claims, and can be individually and / or collectively relied upon and provide sufficient support for the specific embodiments within the scope of the appended claims. In addition, with respect to the language such as "at least", "greater than", "less than", "not more than", etc., which limits or modifies the range, it should be understood that such language includes sub-ranges and / or upper or lower limits. Further, a single number within the disclosed ranges may be relied upon and provides adequate support for specific embodiments within the scope of the appended claims.

[0082] The abbreviations used herein are defined in Table 4.

[0083] Table 4 - Abbreviations

[0084]

Claims

1. A method for preparing a polyorganosiloxane copolymer, wherein the method comprises: 1) combining starting materials, the starting materials comprising A) Formula (R2SiO 2 / 2 ) is derived from the siloxane units, B) Formula (RR'SiO 2 / 2 ) is derived from siloxane units, wherein each R is independently selected from an alkyl group and a haloalkyl group, and R' represents an alkenyl group, and C) a base catalyst, Thus forming a mixture; 2) stirring the mixture at a temperature sufficient to form a reaction mixture comprising the copolymer via an equilibrium reaction; 3) using Raman spectroscopy to monitor a spectral region including a characteristic Raman band corresponding to the decoupled (RR'SiO 2 / 2 ) unit concentration and coupled (RR'SiO 2 / 2 ) units, or both; 4) Stopping the equilibrium reaction when a target value associated with the characteristic Raman band is reached.

2. The method according to claim 1, wherein the target value is selected from i) Characteristic Raman band height or area, ii) the rate of change of the characteristic Raman band height or area, iii) a mathematical transformation of one or more of i) and ii), and iv) chemometric analysis of said spectral region comprising said characteristic Raman band.

3. The method according to claim 2, wherein the target value is the change rate of the characteristic Raman band height or the change rate of the characteristic Raman band area, and the change rate has a value of 0% to 10% of its maximum absolute value that can be measured during the equilibrium reaction.

4. The method according to claim 2 or claim 3, wherein a decoupled (RR'SiO 2 / 2 ) Characteristic Raman band area.

5. The process according to any one of claims 1 to 4, wherein the starting materials A) and B) comprise units of the formula (R3SiO 1 / 2 ) t (R2R'SiO 1 / 2 ) u (R2SiO 2 / 2 ) v (RR'SiO 2 / 2 ) w (RSiO 3 / 2 ) x (R'SiO 3 / 2 ) y (SiO 4 / 2 ) z , wherein the subscripts t, u, v, w, x, y and z represent the amount of each unit, t≥0, u≥0, v≥1, w≥1, x≥0, y≥0, z≥0, provided that the amount (v+w) is from 3 to 300, the amount (x+y+z) is from 0 to a value sufficient to provide up to 20 mol% of the unit in the molecule; the amount (t+u+v+w) is ≥3.

6. The process according to any one of claims 1 to 5, wherein the starting material A) is selected from: A1) contains the unit formula (R2SiO 2 / 2 ) c Cyclic polydiorganosiloxane, wherein 3≤c≤12; A2) contains the unit formula (R3SiO 1 / 2 ) a (R2R'SiO 1 / 2 ) d (R2SiO 2 / 2 ) b A linear polydiorganosiloxane wherein 0≤a≤2, 0≤d≤2, the amount (a+d)=2, and 3≤b≤200; and A3) A combination of A1) and A2).

7. The process according to any one of claims 1 to 6, wherein the starting material B) is selected from: B1) has a unit formula (RR'SiO 2 / 2 ) c A cyclic alkenyl functional polydiorganosiloxane wherein 3≤c≤12; B2) has a unit formula (R3SiO 1 / 2 ) a (R2R'SiO 1 / 2 ) d (RR'SiO 2 / 2 ) e A linear alkenyl functional polydiorganosiloxane wherein 0≤a≤2, 0≤d≤2, the amount (a+d)=2, and 3≤e≤200; and B3) A combination of B1) and B2).

8. The process according to any one of claims 1 to 5, wherein the polydiorganosiloxane comprises both starting materials A) and B) in the same molecule.

9. The process according to any one of the preceding claims, wherein the process is performed batchwise.

10. The process according to any one of the preceding claims, wherein the catalyst is a heterogeneous catalyst.

11. The process according to any one of the preceding claims, wherein the starting material in step 1) is free of water.

12. The process according to any one of the preceding claims, wherein the starting material in step 1) further comprises D) a capping agent.

13. The method of claim 12, wherein the capping agent comprises a unit formula: (R3SiO 1 / 2 ) e (R2R'SiO 1 / 2 ) f (R2SiO 2 / 2 ) g (RR'SiO 2 / 2 ) h , where 0≤e≤2, 0≤f≤2, the quantity (e+f)=2; subscript g≥0, subscript h≥0; and 0≤(g+h)≤30.

14. The method according to any one of the preceding claims, wherein the monitoring in step 3) is performed via real-time and in situ analysis of the reaction mixture.

15. The method of any one of the preceding claims, wherein each R' is selected from vinyl, allyl and hexenyl.

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