Selective polyurethane prepolymer synthesis

Abstract

The present invention relates to a selective process for producing polyurethane prepolymers, to the polyurethane prepolymers obtainable from this process, and also to a process for producing moisture-crosslinking silylated polymers, more particularly silane-functional hybrid polymers, and also to the use thereof in CASE sectors (coatings, adhesives, sealants and elastomers).

Claims

1. Process for the production of polyurethane prepolymers with a molecular weight profile, measured by gel permeation chromatography, of the polyurethane prepolymers from 2000 Da (x.sub.1) to 200000 Da (x.sub.3) along an x-axis has a first section with an area integral F.sub.I and a second section with an area integral F.sub.II, for which a ratio F.sub.II/F.sub.I is between 0 up to and including 0.4, where the first section extends from x.sub.1 to x.sub.2 and the second section extends from x.sub.2 to x.sub.3, and x.sub.2 defines an extreme point between the last intensity maximum (M1a) in the first section, situated in the region of the molecular weight of the hydroxy-functionalized polymer, and a subsequent intensity maximum (M2) in the second section, by a reaction of I. isophorone diisocyanate (IPDI) with II. a hydroxy-functionalized polymer having a number-average molecular weight Mn of 3500 to 100000 Da, in the presence of a catalyst, characterized in that, the molar ratio of NCO groups to hydroxyl groups in the reaction of I. with II. is from 3.0:1 to 1.8:1 and that the temperature in the reaction of I. with II. is between 20 C. and 90 C. and wherein the catalyst is heptaisobutyl POSS-titanium (IV) ethoxide (TiPOSS) and the total catalyst amount is between 3 and 80 ppm, based on the total weight of the hydroxy-functionalized polymer used.

2. Process according to claim 1, wherein the peak (M1a) corresponds to the molecular weight range of polyurethane prepolymers of the following formula A, ##STR00014## in which R.sup.Iso is the structural unit of IPDI and R.sup.Poly is the structural unit of the hydroxy-functionalized polymer, where n is x+y and the functionality n indicates the number of OH groups in the hydroxy functionalized polymer.

3. Process according to claim 1, characterized in that the hydroxy-functionalized polymer is selected from the group consisting of polyether polyols, polyester polyols, polycarbonate polyols and a mixture thereof.

4. Process according to claim 1, characterized in that the hydroxy-functionalized polymer is selected from the group consisting of polyoxyalkylene diols, polyoxyalkylene triols, and mixtures thereof.

5. Process according to claim 1, characterized in that the hydroxy-functionalized polymer is selected from the group consisting of polyester polyols and polyether polyols.

Description

EXAMPLES

(1) I. GPC Data

(2) Instrument and Parameters of STD-GPC Measurement:

(3) Chromatographic System:

(4) Degasser: Agilent 1260 Infinity Degasser Pump: Agilent 1260 Infinity IsoPump Autosampler: Agilent 1260 Infinity ALS Column oven: Agilent 1290 Infinity II TCC RI detector: Agilent 1260 Infinity RID Software: PSS WinGPC UniChrom V 8.31, Build 8417
Chromatographic Conditions: DIN: DIN EN ISO 16014-1, DIN 55672-1 Column: 1. PLgel 5 Mixed D (Agilent Technologies) 2. PLgel 5 Mixed D (Agilent Technologies) 3. PLgel 3 m Mixed E (Agilent Technologies) Mobile Phase: Tetrahydrofuran Flow rate: 1 mL/min Temperature: 35 C. Injection volume: 100 L Sample concentration: 1 g/L Molecular weight standards: PSS Polymer-Standards-Service GmbH, Mainz; Germany M.sub.p [Da]: 66000; 42400; 25500; 15700; 8680; 6540; 4920; 3470; 2280; 1306; 370; 266

(5) *The calibration curve is valid between 266 Da and 66000 Da. Values outside these limits are extrapolated.

(6) II. Viscosity

(7) The viscosities were determined using a Brookfield Rheometer DV-3T Extra at 25 C. Spindle size and spindle speed were selected such that the torque is >90%.

(8) III. Infrared (IR) Spectroscopy:

(9) IR monitoring was measured using a ThermoScientific Nicolet iS5 and iD7ATR unit. Evaluation took place with Omnic 9 Software.

Examples I

(10) Chemicals Used:

(11) Acclaim 18200 (Covestro AG; low mono polyoxypropylene diol, OH number 6.0 mg KOH/g, water content approx. 0.02% by weight) 3-Isocyanatomemyl-3,5,5-trimethyl cyclohexyl isocyanate (Desmodur I, Covestro AG, Leverkusen) TiPOSS (heptaisobutyl POSS-titanium(IV) ethoxide), 20% solution in Hexamoll DINCH, BASF) DBTL (dibutyltin dilaurate) BNT Chemicals DBA (di-n-butylamine) purity >99%, TCl Chemicals N-[3-(trimethoxysilyl)propyl]butylamine, DOG Deutsche Olfabrik VTMO, vinyltrimethoxysilane, Acros Organics
A) Production of the Polyurethane Prepolymers of the Invention

Example 1

(12) 200 g (11 mmol) of polypropylene glycol having an approximate number-average molecular weight M.sub.n of 18000 g/mol (OH number=6.01.0 mg KOH/g) were charged to a 500 ml three-necked flask and dried under reduced pressure at 80 C. for one hour. The reduced pressure was subsequently broken with nitrogen. The polyol was cooled to 25 C. 0.01 g (0.016 mmol) of DBTL catalyst and 5.19 g (23 mmol) of isophorone diisocyanate (IPDI) were added with stirring. As soon as the theoretical NCO content of 0.52 wt % was reached, a determination was made of the viscosity of the NCO prepolymer [46000 mPas (25 C., Brookfield viscometer)]. For the GPC analysis the prepolymer was reacted with 3.02 g (23 mmol) of di-n-butylamine and stirred at 25 C. for 20 minutes. The reaction was monitored by IR spectroscopy (disappearance of the NCO band (2270 cm.sup.1)). The ratio of the area integral F.sub.I in the first section (x.sub.1 to x.sub.2) of the molar weight distribution and the area integral F.sub.II in the second section of the molar weight distribution, F.sub.II/F.sub.I, is 0.29.

Example 2

(13) 200 g (11 mmol) of polypropylene glycol having an approximate number-average molecular weight M.sub.n of 18000 g/mol (OH number=6.01.0 mg KOH/g) were charged to a 500 ml three-necked flask and dried under reduced pressure at 80 C. for one hour. The reduced pressure was subsequently broken with nitrogen. The polyol was cooled to 25 C. 0.01 g (0.011 mmol, pure substance) of TiPOSS catalyst and 5.19 g (23 mmol) of isophorone diisocyanate (IPDI) were added and the reaction mixture was stirred. As soon as the theoretical NCO content of 0.52 wt % was reached, a determination was made of the viscosity of the NCO prepolymer [44000 mPas (25 C., Brookfield viscometer)]. For the GPC analysis the prepolymer was reacted with 3.02 g (23 mmol) of di-n-butylamine and stirred at 25 C. for 20 minutes. The reaction was monitored by IR spectroscopy (disappearance of the NCO band (2270 cm.sup.1)). The ratio of the area integral F.sub.I in the first section (x.sub.1 to x.sub.2) of the molar weight distribution and the area integral F.sub.II in the second section (x.sub.2 to x.sub.3) of the molar weight distribution, F.sub.II/F.sub.I, is 0.27.

(14) Examples 3 to 6 were prepared in accordance with the procedure of examples 1 and 2.

(15) TABLE-US-00001 TABLE 1 Example Catalyst Reaction Viscosity Not Area number Catalyst amount temperature [mPas] inventive x ratio 1 DBTL 50 ppm 25 C. 46 000 0.29 2 TiPOSS 50 ppm 25 C. 44 000 0.27 3 TiPOSS 10 ppm 80 C. 43 000 4 TiPOSS 50 ppm 80 C. 48 000 0.23 5 TiPOSS 37.5 ppm 40 C. 48 000 6 TiPOSS 84 ppm 25 C. 43 000 7 DBTL 50 ppm 80 C. 120 800 x 0.43
B) Production of the Silane-Terminated Polymers (STP), Also Called Silylated Polymers Silane-Terminated Polyols from the Reaction of Isocyanate Prepolymer.

Example 8

(16) 150.2 g (8.3 mmol) of polypropylene glycol having an approximate number-average molecular weight Ma of 18000 g/mol (OH number=6.01.0 mg KOH/g) were charged to a 500 ml three-necked flask and dried under reduced pressure at 90 C. for one hour. The reduced pressure was subsequently broken with nitrogen. The polyol was cooled to 80 C. 1.5 mg (0.0015 mmol, pure substance) of TiPOSS catalyst and 4.01 g (18 mmol) of isophorone diisocyanate (IPDI) were added with stirring. As soon as the theoretical NCO content of 0.52 wt % was reached, 4.97 g (21 mmol) of N-[3-(trimethoxysilyl)propyl]butylamine] were added with stirring and the system was cooled simultaneously to 25 C. The reaction was monitored by IR spectroscopy (disappearance of the NCO band (2270 cm.sup.1)). 2% by weight of VTMO was added to the completed STP. The viscosity of the product was 43000 mPas (25 C., Brookfield viscosity).