DD161062A3 - METHOD FOR THE PRODUCTION OF TRIMETHYL SILICONE-STYLENE-STABILIZED LIQUID POLY (DIMETHYL-METHYLHYDROGEN-SILOXANE) COPOLYMERS - Google Patents

Abstract

The invention relates to the field of silicones. There are obtained by special regulations and process stages, especially by maintaining a - hydrolysis of equal / less than 20 degrees C, a - equilibration temperature of 60-80 degrees C and a - water content of the catalyst of less than or equal to 3 wt .-% silicon-functional polymethylhydrosiloxanes characterized by randomly distributed D high H units, a molecular weight distribution corresponding to a modified Stockmeyer distribution and a polydispersity of less than or equal to 2.5. These compounds can be added without side reactions, which proceed with elimination of hydrogen, and rearrangements of ungesettigte copolymers of ethylene and propylene oxide.

Description

^::,:; : - -. , -1- · 220 884.,.

Process for the preparation of trimethylsiloxy-endblocked liquid poly-idi-ethyl-methylhydrogen

siloxane HJCopolymeren

Field of application of the invention

The invention relates to the preparation of chain-broken polymers of methyl-methylhydrogen-siloxane-type copolymers in which the methylhydrogensiloxy units are randomly distributed over the siloxane chain. The copolymers are intermediates for silicone chemistry and are particularly suitable for addition to unsaturated group-containing hydrocarbons, e.g., due to their content of Si-H groups. Polyoxyalkylenes, for the preparation of foam stabilizers and cell structure regulators for polyurethane chemistry. They are generally applicable where organic substances are to be organosilicon-modified. They do not tend to undesirable side reactions and are characterized by a low polydispersity, a modified Stockmayerverteilung and a low acid number.

Characteristic of the known technical solutions

The preparation of poly (dimethyl-methylhydrogen-siloxane) copolymers can be carried out by various methods typical for silicone chemistry. In order to keep the number of forming Süoxanindividuen small, in particular, the methods of equilibration in the presence of proton-active catalysts are. However, the reproduction of the molecular weight distribution, the proportion and the composition of the forming low molecular weight, volatile linear and cyclic siloxanes in these methods and the ratio of oligomer content to polymer content can not be safely controlled. Due to this fact arise differently composite poly (dimethyl-methylhydrogen-siloxane) ^J copolymers, which make an exact reproduction of the utility properties of derivatives thereof derived from, for example, polysiloxane-polyoxyalkylene Blockkopolymerisaten impossible. Thus, the formation of by-products in the addition reaction, in the case of use in the field of foam stabilizers, ü. U. cause complete destruction of the foam. The presence of the catalyst proved to be partially disadvantageous, why its removal z. B. was proposed by neutralization with sodium carbonate. Low boiling by-products were separated from the equilibrate; Volatile eliminated by volatilization, for example by introducing an inert gas (nitrogen) or applying a vacuum. Nevertheless, difficulties in producing the paly {dimethyl-methylhydro-siloxane) copolymer could not be overcome. It relied on the production of other siloxane blocks, although they required a more unfavorable manufacturing economy. Thus, inter alia, a poly (dimethyl-methylhydrogen-siloxane) block with alpha-omega-terminal Cl atoms was assumed, to the Si-H-Binduhgen dimethylvinylchlorosilane is added. Subsequently, all SiCI groups (with elimination of HCl) are reacted with polyether alcohols. This results in foam stabilizers whose carbo- and silicofunctional polymer moieties are bonded via Si-O-C bridges. Since the Si-0-C bridges hydrolyze more easily than Si-C bridges, these copolymers have the disadvantage of increased susceptibility to hydrolysis. ; <jj - · '' .., ..

Object of the invention

The aim of the present invention is to provide a simple production process for poly (-dimethyl-methylhydrogen-siloxane) copolymers, which ensures the recovery of copolymers having the following properties:

- stable against redistribution, *

- negligible tendency to side reactions, eg. B. under H ₂ or SO ₂ evolution, - high storage stability,

Low acid number,

• constant mass ratio of oligomer to polymer fraction,

The same percentage of methyl-hydrogen-siloxy units in the case of oligomeric as in the polymer fraction,

Addition to allylated polyether results in copolymers with excellent foam stabilizers and cell regulators.

Explanation of the essence of the invention

Surprisingly, it has been found that it is possible to obtain from mixtures of hydrolysates, equilibrates, cyclolosans and / or disiloxanes by equilibration poly (dimethyl-methyl-hydrosiloxane) copolymers which can be added without complications, preferably to allyl-terminated polyethers to give excellent foam stabilizers. The poly (dimethyl-methylhydrogen-siloxane) copolymers are obtained by equilibrating starting mixtures which are composed according to the target stoichiometry in the presence of virtually anhydrous equilibration catalysts, wherein temperatures of between 60 and 80 ° C. are to be maintained. After reaching a constant viscosity is still 10 to 30% of the time, which was necessary until reaching the constant viscosity, weiterzuäquilibrieren.

The composition of the starting mixtures can be carried out from hydrolysates, cohydrolyzates, equilibrates, cyclo siloxanes and / or disiloxanes. It is only important that the target stoichiometry is maintained. Suitable equilibration catalysts are virtually anhydrous cation exchangers which are added in an amount of 1 to 5% by mass, based on the mass of the starting mixture. 96% sulfuric acid can also be used as the catalyst, quantities of from 5 to 10 g per kg of starting mixture being required. The siloxane copolymers according to the invention are characterized by a very low polydispersity which is less than or at most 2.5. In addition, they have a modified stock market distribution and the methyl-hydrogen-siloxy groups are randomly distributed throughout the copolymer. The oligomer content is constant and amounts to a maximum of 13% by mass. The oligomer content, which can be detected by gas chromatography, volatile and cyclic fractions, have the same percentage of methylhydrogensiloxy units as well as the polymer content. The acid number is a maximum of 0.015 mg KOH / g and is so low that a neutralization of the product can be omitted without causing adverse consequences in their further processing.

2- 220 884

The poly (dimethyl-methyl-hydrosiloxane) copolymers prepared according to the invention are particularly suitable for additions to polyoxyalkylenes for obtaining foam stabilizers and cell structure regulators for the.

Polyurethane chemistry.

Examples: ', -'''.'.'.'. . ' ,. '. ''. ''' ^:

The Kohydrolysate be prepared from mono- and difunctional chlorosilanes (trimethylchlorosilane, dimethyldichlorosilane, Methyldiehlorsilan) based on known methods by discontinuously added to the desired molar ratios as a mixture with stirring in an excess of water and saponified in contrast to other methods so that 20-25% hydrochloric acid is formed and the temperature during the hydrolysis 2O ⁰ C does not exceed. The Kohydrolysate be separated, neutralized with soda and the neutralization sludge is drained through a tundish. The resulting oil cloud is clarified in a continuous centrifuge. The hydrolyzates obtained have acid numbers which are less than or equal to 0.015 mg KOH / g. These Kohydrolysate the general formula M ₂ D _n ^ and M ₂ D ^ D _n (m, η - integers or broken numbers) can be in any way with other Kohydrolysaten and / or equilibrates, Dimethylcyclo- and Methylhydrozyklosiloxangemischen and Hexamethyldisiloxan in the presence of acidic and cationic ion exchanger to equilibrate to a desired target stoichiometry. The hydrogen distribution between the polymer and the F igchtigehanteil is the same. The distribution functions of the polymer portion, the distribution of the polymer content in the aquilibrate is adequate and very well reproducible

 The results are summarized in Table 1 below.

Table 1 1 2 "' 522g 3 4 - Sample Nf. M ₂ DgD ₃₃ ,, Use products for 450g Equilibration or _H Zyklehge- Umäquilibrierung: 368g! mixed 12.5kg 11.9 kg M ₂ D _n JD _n (co-hydrolyzate) M ₂ DgD ₃₃₂ - '.' .-. M ₂ DgD _{33> 2} M ₂ DgD ₃₃ ,, .... 622g 17.6 kg 15,1kg D _n -: ^. //. UV: ' Zyklenge - 1 ''':'' Zyklenge Zyklenge mixed mixed mixed TOgMM 0,136 kg MM 0.325 kg MM mm '"-'ν ' ·. ''; Catalyst (sulphonated Ί. ' ^: '. ^: "^;; - ^: 60 2 ... '·. nated polystyrene): 12 % By weight referred to Äquilibriergem. M ₂ DgD _M , ₂ Äquilibriertemperatur 80 «5400 ' 80 80: "· · (° c): :;; '/;'. ..'... 8.5 8.0 7 '". , 6.5 Äquilibrierdauer (h): 0,972 Siloxane block M ₂ D _n JD _n : M ₂ D ^ D ₆₇₄ 1.4038 M ₂ DgD ₇₅ M ₂ DiJD ₅₆ Zielstöchiometrie: «5400 ' 95.8 "6025 "4555 Numeric ben molecular weight: 16.9 93.1 15.0 14.0 MolverhältriisD / D ^H : 0.971 , -. · ''_;'. * 0.970 0.969 Density (df): 1.4040 0,020 1.4040 1.4040 Refractive index (n _D ²⁰ ): 92.1 99.7 78.5 Viscosity: V ₂₀ [CSt]: 89.4 96.7 76.1 r / ₂ o [mPa -S = cP]: - '. 0,149 104 115 Flash point [ ⁰ C]: 0,020 0,151 0.009 0,020 Acid number [mg KOHg " ¹ ]: Bonded to Si Hydrogen: 0,075 - 0.084 0,089 H _Si % (calculated):: 0,076 0.083 0.087 ^; - (Found,) - _Hs%: -. oligomers: - ''. '". By VaL-Destill.  - '' '- - determined (%): By gas chromatogra - 5:34. ' ' 7.27 phie best. (%):  - - 2.2 2.4 Polydispersity (a):

ο

220 884

Table 1 (continued) 5 .6 7 '. ^8th ' Example no.   - Use products for - ·. ' Equilibration or Umäquilibrierung: 1000 kg 1 000 kg -. 2 ' . 1000 kg 631 kg M ₂ DSD _n (co-hydrolyzate) M ₂ DgD ₇₆ M ₂ DiJD ₆₆ M ₂ Dg; _2B D _{52> 2} M ₂ DgD ₄₄₁₆ Äquilibrat - 70 - - ν · ¹ . , ^: - 13 -. , 11 kg MM MM Catalyst (sulphonated 2 M ₂ DlJD ₆₆ '. 2. '' 5 nated polystyrene): = 4555 Gevy .-% based on 14.0 Äquilibriergem. 70 0.969 80 80 ! Equi ibriertemp (° C).: 11 1.4040 11 10.5 Äquilibrierdauer (h): 80.1 Siloxane block M ₂ DmD _n : M ₂ DgD ₇₅ 77.6 M ₂ DU ₂₅ D ₅₂₂ M ₂ D ^ ₂₅ D ₅₂₂ Zieistöchiometrie: = 6025 95. = 4290 = 4290 Numeric ber. Molar mass: 15.0 0,020 12.3 12.3 Molar ratio D / D ^H : 0.970 0.970 0.969 Density (df): 1.4041 1.4040 1.4040 Refractive index (n _D ²⁰ ): 106.7 0,089 80.8 ^! 75.5 Viscosity: v ₂₀ (cSt): 103.5 0.087 78.4 72.6 ? 7 _2O [mPa-s = cP]: 99 105 103 Flash point ( ⁰ C): 0,020 0,020 0,013 Acid number (mg KOHg- ¹ ): 9.8 Bonded to Si Hydrogen: 0.084 10.11 0,100 0,100 H _Si % (over,): 0.084 2.4 0,102 0.103 H _Si % (gef.): oligomers: By vacuum distillation. 10.6 10.5 11.0 determined (%): By gas chromatogra 10.73 11.7 13.9 phie (%): 2.2 2.5 2.5 Polydispersity (a): D ^H = CH ₃ HSiO D = (CH ₃ I ₂ SiO M = (CH ₃ I ₃ SiOV ₂

Claims (3)

-4-220,884 invention claims 1. A process for the preparation of trimethylsiloxy-terminated liquid poly (dimethylhydrogensiloxane) copolymers having randomly distributed over the siloxane chain Methylhydrogensiloxyein'neiten, with an acidity! less than or equal to 0.015 mg KOH / g, with a modified stock market distribution of the molecular weights which cause no side reactions under H ₂ - or SO ₂ evolution in the addition to unsaturated polyether and even here · subject to no rearrangement and with a content of less than 13 Mass% of up to 220 ° C by gas chromatography as linearly detectable linear or cyclic oligomers having the same content of methylhydrogen-siloxy units as the polymer content, by equilibration or re-equilibration between 50 and 90 ⁰ C, preferably between 60 and 8O ⁰ C of mixtures according to the target stoichiometry composed of hydrolysates, Kohydrolysaten, equilibrates, cyclolosans and / or disiloxanes, characterized in that according to the target stoichiometry composite or correspondingly composed mixtures in the presence of nearly anhydrous equilibration the 1.1 to 1.3 times Zei t, based on the equilibration time required to reach a constant viscosity. 2. The method according to item 1, characterized in that 1 to 3 mass% sulfonated ion exchangers based on polystyrene and / or divinylbenzene are used as equilibration catalyst. 3. The method according to item 1, characterized in that as equilibration catalyst 0.5 to 1 mass%, based on the mass of the equilibration, 96% sulfuric acid is used.