DIMER FATTY ACID-POLYESTER DIOL-BASED POLYMER, CONTAINING ISOCYANATE GROUPS

Abstract

A polyester urethane polymer containing isocyanate groups and being liquid at ambient temperature, obtained by reacting at least one monomeric diisocyanate and dimer fatty acid-based polyester diol having OH-number ranging between 28 and 120 mg KOH/g in NCO/OH ratio of at least 3/1, and by subsequently removing large part of monomeric diisocyanate by means of suitable separation process, wherein polymer has NCO content ranging between 1.5 and 6% by wt. and maximum monomeric diisocyanate content of 0.5% by wt. The polymer permits the production of moisture-curing polyurethane compositions for application in ambient temperatures, having improved properties in terms of open time, adhesion, application and weather resistance, with unchanged good properties of storage stability, curing rate, strength, ductility, elasticity and hazardous material classification. Compositions of this type are particularly suitable for use as elastic adhesives in replacement glass for vehicles.

Claims

1. A room temperature liquid polyester urethane polymer containing isocyanate groups, obtained from the reaction of at least one monomeric diisocyanate and a dimer fatty acid-based polyester diol having an OH number in the range from 28 to 120 mg KOH/g in an NCO/OH ratio of at least 3/1, followed by removal of a majority of the monomeric diisocyanate by means of a suitable separation method, wherein it has an NCO content in the range from 1.5% to 6% by weight and a monomeric diisocyanate content of not more than 0.5% by weight.

2. The polyester urethane polymer as claimed in claim 1, wherein the monomeric diisocyanate is diphenylmethane 4,4′-diisocyanate.

3. The polyester urethane polymer as claimed in claim 1, wherein the dimer fatty acid-based polyester diol is amorphous.

4. The polyester urethane polymer as claimed in claim 1, wherein the NCO/OH ratio is in the range from 3/1 to 10/1.

5. The polyester urethane polymer as claimed in claim 1, wherein it has a viscosity at 20° C. in the range from 100 to 1'000 Pa.Math.s, determined with a cone-plate viscometer having a cone diameter 25 mm, cone angle 1, cone tip-plate distance of 0.5 mm, at a shear rate of 50 s.sup.−1.

6. The use of the polyester urethane polymer as claimed in claim 1 as adhesion promoter in a moisture-curing polyurethane composition.

7. The use as claimed in claim 6, wherein the polyester urethane polymer is used in an amount in the range from 0.5% to 15% by weight, based on the overall polyurethane composition.

8. A moisture-curing polyurethane composition suitable as elastic adhesive and/or sealant, comprising at least one polyether urethane polymer containing isocyanate groups, and the polyester urethane polymer containing isocyanate groups as claimed in claim 1.

9. The moisture-curing polyurethane composition as claimed in claim 8, wherein the polyether segments in the polyether urethane polymer consist of at least 80% 1,2-propyleneoxy units.

10. The moisture-curing polyurethane composition as claimed in claim 8, wherein the polyether urethane polymer has an NCO content in the range from 1% to 5% by weight.

11. The moisture-curing polyurethane composition as claimed in claim 8, wherein at least one further constituent selected from meltable components, blocked amines, fillers, plasticizers, diisocyanate oligomers, catalysts and stabilizers is present.

12. The moisture-curing polyurethane composition as claimed in claim 8, wherein it contains 20% to 60% by weight of polyether urethane polymer containing isocyanate groups, 0.5% to 10% by weight of inventive dimer fatty acid-based polyester urethane polymer containing isocyanate groups, 0% to 5% by weight of meltable component, 20% to 60% by weight of fillers, 0% to 35% by weight of plasticizers, and optionally further constituents.

13. The moisture-curing polyurethane composition as claimed in claim 8, wherein a total of less than 0.1% by weight of monomeric diisocyanates is present.

14. A method of bonding or sealing, comprising the steps of (i) applying the polyurethane composition as claimed in claim 8 to a first substrate and contacting the composition with a second substrate within the open time of the composition, or to a first and to a second substrate and joining the two substrates within the open time of the composition, or between two substrates, (ii) curing the composition by contact with moisture.

15. An article obtained from the method as claimed in claim 14.

Description

EXAMPLES

[0182] Working examples are adduced hereinafter, which are intended to elucidate the invention described. The invention is of course not limited to these described working examples.

[0183] “Standard climatic conditions” (“SCC”) refer to a temperature of 23±1° C. and a relative air humidity of 50±5%.

[0184] Unless otherwise stated, the chemicals used were from Sigma-Aldrich Chemie GmbH.

[0185] Polyols Used: [0186] Priplast® 1837: dimer fatty acid-based amorphous polyester diol, OH number 110 mg KOH/g, liquid at room temperature (from Croda) [0187] Priplast® 1838: dimer fatty acid-based amorphous polyester diol, OH number 56 mg KOH/g, liquid at room temperature (from Croda) [0188] Priplast® 3196: dimer fatty acid-based amorphous polyester diol, OH number 37 mg KOH/g, liquid at room temperature (from Croda) [0189] Priplast® 3197: dimer fatty acid-based amorphous polyester diol, OH number 56 mg KOH/g, liquid at room temperature (from Croda) [0190] Desmophen® 5031 BT: glycerol-started ethylene oxide-terminated polyoxypropylene triol, OH number 28 mg KOH/g (from Covestro) [0191] Acclaim® 4200: polyoxypropylene diol, OH number 28 mg KOH/g (from Covestro) [0192] Dynacoll® 7360 room temperature solid, semicrystalline polyester diol, OH number 34 mg KOH/g (from Evonik)

[0193] Preparation of Polymers Containing Isocyanate Groups:

[0194] Viscosity was measured with a thermostated Rheotec RC30 cone-plate viscometer (cone diameter 25 mm, cone angle 1°, cone tip-plate distance 0.5 mm, shear rate 50 s.sup.−1).

[0195] Monomeric diisocyanate content was determined by means of HPLC (detection via photodiode array; 0.04 M sodium acetate/acetonitrile as mobile phase) after prior derivatization by means of N-propyl-4-nitrobenzylamine.

[0196] Polymer DP-1:

[0197] 597.5 g of Priplast® 1838 and 402.5 g of diphenylmethane 4,4′-diisocyanate (Desmodur® 44 MC L, from Covestro) were reacted at 80° C. to give a polyester urethane polymer having an NCO content of 11.0% by weight, a viscosity of 36 Pa.Math.s at 20° C. and a diphenylmethane 4,4′-diisocyanate content of about 26% by weight.

[0198] Subsequently, the volatile constituents, especially a majority of the diphenylmethane 4,4′-diisocyanate, were removed by distillation in a short-path evaporator (jacket temperature 180° C., pressure 0.1 to 0.005 mbar, condensation temperature 47° C.). The polyester urethane polymer thus obtained was slightly cloudy and was of fluid, viscous consistency at room temperature. It had an NCO content of 2.8% by weight, a viscosity of 312 Pa.Math.s at 20° C., 119 Pa.Math.s at 30° C., 48 Pa.Math.s at 40° C. and 11.5 Pa.Math.s at 60° C., and a diphenylmethane 4,4′-diisocyanate content of 0.09% by weight.

[0199] Polymer DP-2:

[0200] 445.0 g of Priplast® 1837 and 555.0 g of diphenylmethane 4,4′-diisocyanate (Desmodur® 44 MC L, from Covestro) were reacted at 80° C. to give a polyester urethane polymer having an NCO content of 14.8% by weight, a viscosity of 6.5 Pa.Math.s at 20° C. and a diphenylmethane 4,4′-diisocyanate content of about 35% by weight.

[0201] Subsequently, the volatile constituents, especially a majority of the diphenylmethane 4,4′-diisocyanate, were removed as described for polymer DP-1. The polyester urethane polymer thus obtained was slightly cloudy and was of fluid, viscous consistency at room temperature. It had an NCO content of 4.8% by weight, a viscosity of 11 Pa.Math.s at 60° C. and a diphenylmethane 4,4′-diisocyanate content of 0.06% by weight.

[0202] Polymer DP-3:

[0203] 663.0 g of Priplast® 3196 and 337.0 g of diphenylmethane 4,4′-diisocyanate (Desmodur® 44 MC L, from Covestro) were reacted at 80° C. to give a polyester urethane polymer having an NCO content of 9.4% by weight, a viscosity of 57 Pa.Math.s at 20° C. and a diphenylmethane 4,4′-diisocyanate content of about 23% by weight.

[0204] Subsequently, the volatile constituents, especially a majority of the diphenylmethane 4,4′-diisocyanate, were removed as described for polymer DP-1. The polyester urethane polymer thus obtained was slightly cloudy and was of fluid, viscous consistency at room temperature. It had an NCO content of 2.2% by weight, a viscosity of 17 Pa.Math.s at 60° C. and a diphenylmethane 4,4′-diisocyanate content of 0.06% by weight.

[0205] Polymer DP-4:

[0206] 600.0 g of Priplast® 3197 and 400.0 g of diphenylmethane 4,4′-diisocyanate (Desmodur® 44 MC L, from Covestro) were reacted at 80° C. to give a polyester urethane polymer having an NCO content of 10.7% by weight, a viscosity of 28 Pa.Math.s at 20° C. and a diphenylmethane 4,4′-diisocyanate content of about 25% by weight.

[0207] Subsequently, the volatile constituents, especially a majority of the diphenylmethane 4,4′-diisocyanate, were removed as described for polymer DP-1. The polyester urethane polymer thus obtained was slightly cloudy and was of fluid, viscous consistency at room temperature. It had an NCO content of 2.8% by weight, a viscosity of 16 Pa.Math.s at 60° C. and a diphenylmethane 4,4′-diisocyanate content of 0.08% by weight.

[0208] Polymer DP-5:

[0209] 620.0 g of Priplast® 1838 and 379.9 g of 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (Vestanat® IPDI, from Evonik) were reacted in the presence of 0.01 g of dibutyltin dilaurate at 80° C. to give a polyester urethane polymer having an NCO content of 11.8% by weight, a viscosity of 17 Pa.Math.s at 20° C. and a 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane content of about 20% by weight. Subsequently, the volatile constituents, especially a majority of the 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane, were removed by distillation in a short-path evaporator (jacket temperature 160° C., pressure 0.1 to 0.005 mbar). The polyester urethane polymer thus obtained was slightly cloudy and was of fluid, viscous consistency at room temperature. It had an NCO content of 3.1% by weight, a viscosity of 153 Pa.Math.s at 20° C. and a 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane content of 0.23% by weight.

[0210] Polymer PP-1:

[0211] 725.0 g of Desmophen® 5031 BT and 275.0 g of diphenylmethane 4,4′-diisocyanate (Desmodur® 44 MC L, from Covestro) were reacted by a known method to give a polyether urethane polymer having an NCO content of 7.6% by weight, a viscosity of 6.5 Pa.Math.s at 20° C. and a diphenylmethane 4,4′-diisocyanate content of about 20% by weight.

[0212] Subsequently, the volatile constituents, especially a majority of the diphenylmethane 4,4′-diisocyanate, were removed as described for polymer DP-1. The polyether urethane polymer thus obtained had an NCO content of 1.7% by weight, a viscosity of 19 Pa.Math.s at 20° C. and a diphenylmethane 4,4′-diisocyanate content of 0.04% by weight.

[0213] Polymer PP-2:

[0214] 727.0 g of Acclaim® 4200 and 273.0 g of diphenylmethane 4,4′-diisocyanate (Desmodur® 44 MC L, from Covestro) were reacted by a known method to give a polyether urethane polymer having an NCO content of 7.6% by weight, a viscosity of 5.2 Pa.Math.s at 20° C. and a diphenylmethane 4,4′-diisocyanate content of about 18% by weight.

[0215] Subsequently, the volatile constituents, especially a majority of the diphenylmethane 4,4′-diisocyanate, were removed as described for polymer DP-1. The polyether urethane polymer thus obtained had an NCO content of 1.8% by weight, a viscosity of 15.2 Pa.Math.s at 20° C. and a diphenylmethane 4,4′-diisocyanate content of 0.08% by weight.

[0216] Polymer M:

[0217] 1000 g of Dynacoll® 7360 and 142 g of diphenylmethane 4,4′-diisocyanate (Desmodur® 44 MC L, from Covestro) were reacted at 80° C. to give a room temperature solid polymer having an NCO content of 2.0% by weight and a diphenylmethane 4,4′-diisocyanate content of 2.3% by weight.

[0218] Polymers DP-1 to DP-5 are dimer fatty acid-based polyester urethane polymers. Polymers PP-1 and PP-2 are polyether urethane polymers. Polymer M is a room temperature solid polymer that was used as meltable component.

[0219] Moisture-Curing Polyurethane Compositions:

[0220] Compositions Z1 to Z5:

[0221] For each composition, the ingredients specified in table 1 were well mixed in the amounts specified (in parts by weight) by means of a planetary mixer under reduced pressure and with exclusion of moisture, and the composition was dispensed into a tubular bag with an airtight seal and stored at room temperature.

[0222] For rapid curing, a water-containing accelerator component was added to the composition on application. For this purpose, the composition was applied from a PowerCure dispenser (available from Sika Schweiz AG), with metered addition of 2% by weight of a water-containing paste into the composition on expression and mixing-in by means of a dynamic mixer.

[0223] Adhesion to residual adhesive bead was determined on a cured and aged adhesive layer. For this purpose, a commercially available polyurethane adhesive for bonding of panes (Sikaflex® -250 SV-3, from Sika Automotive Hamburg GmbH) was applied in the form of a triangular bead of width about 8 mm and height about 10 mm to a glass body, covered with a silicone-coated release paper, pressed to a layer thickness of about 5 mm and cured under standard climatic conditions for 7 days, the release paper was removed and the compressed adhesive bead was aged at 80° C. for 14 days. Subsequently, the cured and aged an adhesive bead was cut away from the glass body down to a layer thickness of about 1 mm.

[0224] Thereafter, under standard climatic conditions, the accelerated composition was applied from the PowerCure dispenser in the form of a triangular bead of width about 8 mm and height about 10 mm to strips of silicone-coated release paper. After the wait time specified in each case in table 1, the triangular beads applied to the release paper were upturned and placed onto the residual adhesive bead remaining on the glass body in such a way that the release paper was on top and the composition was in contact with the residual adhesive bead. Subsequently, the composition was pressed to a layer thickness of about 5 mm and cured under standard climatic conditions for 7 d, then the release paper was removed and the adhesion of the cured composition on the residual adhesive bead was tested by making an incision into the cured composition at the narrow end just above the bond surface, holding the incised end of the composition with rounded tweezers and attempting to pull the composition away from the substrate (=residual adhesive bead). Then the composition was incised again down to the substrate, the part that had been cut away was rolled up with the rounded tweezers and an attempt was again made to pull the composition away from the substrate. In this way, the composition was cut away from the substrate by pulling. Subsequently, bonding was assessed with reference to the failure profile using the following scale:

[0225] “very good” represents more than 95% cohesive failure,

[0226] “good” represents 75% to 95% cohesive failure,

[0227] “moderate” represents 50% to 75% cohesive failure,

[0228] “poor” represents less than 50% cohesive failure, and

[0229] “no adhesion” represents 0% cohesive failure or 100% adhesive failure

[0230] The results are reported in table 1.

[0231] Compositions labeled “(Ref.)” are comparative examples.

TABLE-US-00001 TABLE 1 Composition (in parts by weight) and properties of Z1 to Z5. .sup.1 2,2′-dimorpholinodiethyl ether Z5 Composition Z1 Z2 Z3 Z4 (Ref.) Polymer DP-1 5.0 — — — — Polymer DP-2 — 5.0 — — — Polymer DP-3 — — 5.0 — — Polymer DP-4 — — — 5.0 — Polymer PP-1 36.8 36.8 36.8 36.8 41.8 Polymer M 2.8 2.8 2.8 2.8 2.8 Dioctyl adipate 17.1 17.1 17.1 17.1 17.1 Chalk 20.0 20.0 20.0 20.0 20.0 Carbon black 18.0 18.0 18.0 18.0 18.0 DMDEE .sup.1 0.3 0.3 0.3 0.3 0.3 Adhesion to very good good very good very good moderate residual adhesive very good good very good very good good bead very good good very good very good moderate after wait time 0 min very good moderate very good good poor 5 min 7 min 10 min

[0232] Compositions Z6 and Z7:

[0233] Each composition was produced as described for composition Z1 using the ingredients specified in table 2 in the amounts specified (in parts by weight), dispensed into an aluminum cartridge with an airtight seal, and stored at room temperature.

[0234] Each composition was applied between two silicone-coated release papers, pressed to a film of thickness 2 mm and stored under standard climatic conditions for 14 days. After the release papers had been removed, rectangular test specimens (75×150 mm) were cut out of the cured film and tested in a QUV weathering device for the time specified in table 2, and then the weathered surface was tested for carbon black staining by first pressing a transparent adhesive tape onto the surface by hand and then sticking it to a white printer paper. Carbon black staining was rated as “no” if a light gray stain was then visible, carbon black staining was rated as “moderate” in the case of a dark gray stain, and carbon black staining was rated as “severe” in the case of a black stain.

[0235] The results are reported in table 2.

[0236] Compositions labeled “(Ref.)” are comparative examples.

TABLE-US-00002 TABLE 2 Composition (in parts by weight) and properties of Z6 and Z7..sup.1 Tinuvin ® 292 (from BASF) Z7 Composition Z6 (Ref.) Polymer DP-1 5.0 — Polymer PP-1 22.3 27.3 Polymer PP-2 10.0 10.0 Diisodecyl phthalate 16.6 16.6 Stabilizer.sup.1 1.0 1.0 Chalk 25.0 25.0 Carbon black 20.0 20.0 2,2′-Dimorpholinodiethyl ether 0.1 0.1 Carbon black staining: 200 h QUV no moderate 500 h QUV no severe 3′000 h QUV no severe

[0237] Compositions Z8 to Z16:

[0238] Each composition was produced as described for composition Z1 using the ingredients specified in tables 3 and 4 in the amounts specified (in parts by weight), dispensed into an aluminum cartridge with an airtight seal, and stored at room temperature.

[0239] Each composition was tested as follows:

[0240] Measures determined for processibility or applicability of the composition were expression force, sag resistance and threading. A low expression force, a high sag resistance and short threading are representative of good processibility or applicability.

[0241] Expression force was determined at 23° C. and at 5° C. A first closed cartridge was stored at 23° C. for 7 days, and a second was stored at 23° C. for 6 days and then at 5° C. for 24 hours. Then the expression force was measured in each case by means of an expression device (Zwick/Roell Z005), by screwing a nozzle of internal diameter 5 mm onto the cartridge and then measuring the force required to express the composition through the nozzle at an expression rate of 60 mm/min. The value reported is the average of the forces that were measured after an expression distance of 22 mm, 24 mm, 26 mm and 28 mm. The sag resistance of each composition was determined by, under standard climatic conditions, applying a triangular bead of width about 8 mm and height about 20 mm to a vertical corrugated cardboard surface in such a way that the triangular bead was arranged as a horizontal strip of width 8 mm with a protruding height (=tip) of 20 mm. After curing under standard climatic conditions, an assessment was made as to whether and how the position of the bead applied had changed. More particularly, the extent to which the tip, measured from the horizontal position, had sagged downward was determined. A sag of less than 1 mm was rated as “very good”, 1 to less than 3 mm as “good”, 4 to 7 mm as “average”, and 8 mm or more as “poor”. A “fluid” composition is defined as one where the material applied moved downward, i.e. ran downward, not just at the tip but also at the base of the triangular bead applied.

[0242] Threading was determined for some compositions by measuring the length of the thread formed by moving the application cartridge away from the triangular bead that had been applied for determination of sag resistance.

[0243] A measure determined for the processing time (open time) was the skin time. For this purpose, a few grams of the composition was applied to cardboard in a layer thickness of about 2 mm and, under standard climatic conditions, the first period of time after which no residues remained any longer on an LDPE pipette used to gently tap the surface of the composition was determined.

[0244] For determination of mechanical properties, each composition was pressed between two silicone-coated release papers to give a film of thickness 2 mm and stored under standard climatic conditions for 14 days. After removing the release papers, some test specimens were punched out and tested as described as follows:

[0245] For determination of tensile strength (“TS”), elongation at break (EaB) and modulus of elasticity at 0.5-5% elongation, dumbbells having a length of 75 mm with a bar length of 30 mm and a bar width of 4 mm were punched out of the film, and these were tested to DIN EN 53504 at a strain rate of 200 mm/min.

[0246] A number of test specimens were also punched out for determination of tear resistance and were tested in accordance with DIN ISO 34 at a strain rate of 500 mm/min.

[0247] Appearance and gloss were determined visually for the determination of the mechanical properties produced film. “Nice” was used to describe a nontacky, even film without blisters.

[0248] To determine the strength of an adhesive bond, lap shear strength (LSS) for some compositions was determined on glass. For this purpose, composite specimens were produced by bonding two glass plates that had been degreased with isopropanol and pretreated with Sika® Aktivator 100 (from Sika Schweiz) in such a way that the overlapping adhesive bond had dimensions of 12×25 mm and a thickness of 4 mm and the glass plates protruded at the top ends. After the composite specimens had been stored under standard climatic conditions for 14 d, lap shear strength was tested to DIN EN 1465 at a strain rate of 20 mm/min. As a measure of the heat and hydrolysis stability of the bond, further test specimens were additionally stored in an air circulation oven at 100° C. for 7 days or at 70° C./100% relative humidity for 7 days, cooled down under standard climatic conditions and tested in the same way. The results are given the addition “14d SCC” or “7d 100° C.” or “7d 70/100”.

[0249] The results are reported in tables 3 and 4.

[0250] Compositions labeled “(Ref.)” are comparative examples.

TABLE-US-00003 TABLE 3 Composition (in parts by weight) and properties of Z8 to Z13. Z9 Z11 Z13 Composition Z8 (Ref.) Z10 (Ref.) Z12 Ref.) Polymer DP-1 5.0 — 5.0 — 5.0 — Polymer PP-1 36.8 41.8 38.2 43.2 39.6 44.6 Polymer M 2.8 2.8 1.4 1.4 — — Dioctyl adipate 17.1 17.1 17.1 17.1 17.1 17.1 Chalk 20.0 20.0 20.0 20.0 20.0 20.0 Carbon black 18.0 18.0 18.0 18.0 18.0 18.0 DMDEE.sup.1 0.3 0.3 0.3 0.3 0.3 0.3 Expression 809 919 653 616 471 249 force 23° C. [N] 5° C. 1002 1235 812 869 685 468 Sag resistance very very very moderate very poor. good good good good fluid Thread formation 6 5 8 11 12 n.m. [mm] Skin time [min] 17 17 17 18 17 22 Tensile strength 8.3 7.6 8.6 [MPa] 8.4 7.7 490 466 513 8.2 Elongation at 502 487 5.5 5.2 4.6 477 break [%] Modulus of 6.1 5.8 4.0 elasticity [MPa] Tear resistance 12.3 11.7 12.0 11.2 11.7 10.0 [N/mm] Appearance/ nice/ nice/ nice/ nice/ nice/ nice/ gloss matt glossy matt glossy matt glossy LSS [MPa] 14 d SCC 4.7 4.5 4.1 4.5 4.6 4.2 7 d 100° C. 5.9 5.8 7.0 5.5 5.3 6.8 7 d 70/100 5.2 5.3 5.0 3.2 5.2 3.5 .sup.12,2′-dimorpholinodiethyl ether

TABLE-US-00004 TABLE 4 Composition (in parts by weight) and properties of Z14 to Z16. Composition Z14 Z15 Z16 Polymer DP-2 5.0 — — Polymer DP-3 — 5.0 — Polymer DP-4 — 5.0 Polymer PP-1 36.8 36.8 36.8 Polymer M 2.8 2.8 2.8 Dioctyl adipate 17.1 17.1 17.1 Chalk 20.0 20.0 20.0 Carbon black 18.0 18.0 18.0 2,2′-Dimorpholinodiethyl ether 0.3 0.3 0.3 Expression force [N] 23° C. 959 633 539 Sag resistance very good very good very good Skin time [min] 17 16 16 Tensile strength [MPa] 7.8 6.9 7.4 Elongation at break [%] 472 493 482 Modulus of elasticity [MPa] 8.1 5.1 5.6 Tear resistance [N/mm] 13.6 12.5 11.4 Appearance/gloss nice/matt nice/matt nice/matt