Method and system for producing a polyurethane polymer by means of a supported catalyst

Abstract

A process for preparing a polyurethane polymer comprises the step of: I) mixing a first component (100) comprising a polyisocyanate with a second reactant component (200) comprising a compound having Zerewitinoff-active hydrogen atoms in a mixing vessel (300) to obtain a reaction mixture (400), wherein the first reactant component (100) and/or the second reactant component (200) are contacted with a catalyst bed (500) before they are mixed in the mixing vessel (300) and/or the reaction mixture (400) is contacted with a catalyst bed (500), wherein the catalyst bed (500) contains a catalyst reversibly sorbed on a substrate, the catalyst catalyses the reaction of isocyanate groups with themselves or with Zerewitinoff-active compounds and the catalyst is released into the first component (100), second component (200) or reaction mixture (400) that is in contact with the catalyst bed (500), such that a reaction mixture (410) containing the catalyst is obtained.

Claims

1. A process for preparing a polyurethane polymer, comprising the step of: I) mixing a first reactant component comprising a polyisocyanate with a second reactant component comprising a compound having Zerewitinoff-active hydrogen atoms in a mixing vessel to obtain a reaction mixture, wherein the first reactant component and/or the second reactant component are contacted with a catalyst bed before they are mixed in the mixing vessel and/or the reaction mixture is contacted with a catalyst bed, wherein the catalyst bed contains a catalyst reversibly sorbed on a substrate, the catalyst catalyses the reaction of isocyanate groups with themselves or with Zerewitinoff-active compounds, and the catalyst is released into the first component, second component or reaction mixture that is in contact with the catalyst bed, such that a reaction mixture containing the catalyst is obtained.

2. The process according to claim 1, wherein: a stream of the first reactant component is combined with a stream of the second reaction component in a mixer to obtain a stream of the reaction mixture and at least one stream selected from the stream of the first reactant component, the stream of the second reactant component and the stream of the reaction mixture flows through the catalyst bed, such that the catalyst is released into the stream that flows through the catalyst bed.

3. The process according to claim 1, wherein the catalyst is released in such a way that the reaction mixture containing the catalyst contains the catalyst in a proportion of ≥1 ppm to ≤5000 ppm, based on the weight of the reaction mixture.

4. The process according to claim 1, wherein the reaction mixture comes into contact with the catalyst bed, and the first and second reactant components do not come into contact with the catalyst bed.

5. The process according to claim 1, wherein the first and second reactant components do not contain any catalyst before being mixed in the mixing vessel.

6. The process according to claim 1, wherein the substrate in the catalyst bed comprises particles having channels that have an extent of ≥1 angstrom to ≤50 angstroms in at least one spatial direction.

7. The process according to claim 1, wherein the catalyst selected is dimethyltin dilaurate, dibutyltin dilaurate, dioctyltin dilaurate, tin bis(dodecylmercaptide), tin bis(2-ethylhexylthioglycolate), tin diacetate, tin maleate, bisthioglyceroltin, octyltin tris(2-ethylhexylthioglycolate), bis(β-methoxycarbonylethyl)tin dilaurate, tetraisopropyl titanate, tetra-tert-butyl orthotitanate, tetra(2-ethylhexyl)titanium and bis(ethylacetoacetato)titanium diisopropoxide, bismuth(III) tris(2-ethylhexanoate), bismuth laurate or mixtures thereof.

8. The process according to claim 1, wherein the catalyst bed is in the form of at least one exchangeable cartridge.

9. The process according to claim 1, wherein the catalyst bed is in the form of a multitude of mutually fluidically sealed channels which contain substrates and catalysts sorbed thereon, and through which the first reactant component, the second reactant component or the reaction mixture flows independently of one another on instruction by a control unit.

10. The process according to claim 1, wherein the catalyst bed has been purged with a solvent prior to commencement of the process.

11. A system for preparation of a polyurethane polymer, comprising a mixing vessel for mixing of a first and second reactant component to obtain a reaction mixture, wherein the system has at least one catalyst bed with which the first or second reactant component comes into contact before it enters the mixing vessel and/or which is contacted by the reaction mixture before it leaves the mixing vessel, and wherein the catalyst bed contains a catalyst sorbed reversibly on a substrate for catalysis of the reaction of isocyanate groups with themselves or with Zerewitinoff-active compounds.

12. The system according to claim 11, wherein the catalyst bed is in the form of at least one exchangeable cartridge.

13. The system according to claim 11, wherein the catalyst bed is in the form of a multitude of mutually fluidically sealed channels which contain substrates and catalysts sorbed thereon, and through which the first reactant component, the second reactant component or the reaction mixture flows independently of one another on instruction by a control unit.

14. The system according to claim 11, wherein the system is designed as a spray gun with a conduit (320) for transport of the reaction mixture out of the mixing vessel to a nozzle and the catalyst bed is disposed in said conduit.

15. The system according to claim 11, wherein the mixing vessel is designed as a mixing head that mixes a stream of the first reactant component with a stream of second reactant component to obtain a stream of the reaction mixture and at least one stream selected from the stream of the first reactant component, the stream of the second reactant component and a stream of the reaction mixture flows through the catalyst bed, such that the catalyst is released into the stream that flows through the catalyst bed.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is further described by reference to the figures that follow, but without being limited thereto. The figures show:

(2) FIGS. 1 and 2 schematics of systems according to the invention in the form of a spray gun

(3) FIGS. 3, 4 and 5 schematics of systems according to the invention in the form of a mixing head

(4) FIG. 1 shows a system according to the invention in the form of a spray gun. Already present in the mixing vessel 300 is a reaction mixture 400 of the first reactant component 100 comprising a polyisocyanate and the second reactant component 200 comprising a polyol. If compressed air is applied to the conduit section 310, the effect of this is that reaction mixture 400 is sucked into the suction tube 320. The reaction mixture 400 passes through the catalyst bed 500 disposed in an exchangeable cartridge 600 in the flow path of the reaction mixture 400. As it passes through the catalyst bed, catalyst is released to the reaction mixture, such that catalyst-containing reaction mixture 410 can leave the spray gun. This reaction mixture 410 can then be applied as paint to a surface. The cartridge 600 may be introduced into the conduit 320, for example by means of two screw threads at their ends.

(5) FIG. 2 shows a further system according to the invention in the form of a spray gun. Already present in the mixing vessel 300 is a reaction mixture 400 of the first reactant component 100 comprising a polyisocyanate and the second reactant component 200 comprising a polyol. If compressed air is applied to the conduit section 310, the effect of this is that reaction mixture 400 is sucked into the suction tube 320. The reaction mixture 400 passes through the catalyst bed 500 disposed in an exchangeable cartridge 600 in the flow path of the reaction mixture 400. As it passes through the catalyst bed, catalyst is released to the reaction mixture, such that catalyst-containing reaction mixture 410 can leave the spray gun. This reaction mixture 410 can then be applied as paint to a surface. The cartridge 600 may be introduced into the conduit 320, for example by means of two screw threads at their ends. By contrast with the spray gun shown in FIG. 1, the cartridge 600 with the catalyst bed 500 is disposed closer to the nozzle. According to the application, the cartridge 600 may also constitute the discharge nozzle for the paint.

(6) FIG. 3 shows a system according to the invention that is suitable for continuous applications. The mixing vessel here is designed as a mixing head 300 in which a stream of the first reactant component 100 comprising a polyisocyanate and a stream of the second reactant component 200 comprising a polyol meet and are mixed, and form the non-catalyst-containing reaction mixture 400. The stream of this reaction mixture 400 passes through the catalyst bed 500 disposed in an exchangeable cartridge 600 in the flow path of the reaction mixture 400. As it passes through the catalyst bed, catalyst is released to the reaction mixture, such that catalyst-containing reaction mixture 410 can leave the spray gun. This reaction mixture 410 can then be applied as paint to a surface. The cartridge 600 may be introduced between the mixing head outlet and further conduits, for example, by means of two screw threads at their ends.

(7) FIGS. 4 and 5 show variants of the positioning of the cartridge 600 compared to the embodiment shown in FIG. 3. In FIG. 4, the cartridge is disposed in the flow path of the first reactant component 100 before it enters the mixing head 300. In FIG. 5, the cartridge is disposed in the flow path of the second reactant component 200 before it enters the mixing head 300.

(8) The invention is illustrated in detail by the examples which follow, but without being restricted thereto. The substrate used in Examples 1 and 2 was Sylobead MS 548, a molecular sieve of the 13× type having a pore size of about 10 angströms and an average particle size of 1.5 mm. The isocyanate component (B) and the polyol component (A) had the following compositions (figures in parts by weight):

(9) TABLE-US-00001 Component A Setalux D A HS 1272 (about 72% in BA); 137.75 polyacrylate polyol Tego Airex 945 0.50 Tinuvin 292 (50% in butyl acetate) 1.48 Tinuvin 384-2 (50% in butyl acetate) 2.20 Butyl acetate 4.35 Butyl acetate/methoxypropyl acetate/ 20.35 xylene (1/1/1) Component B Desmodur N 3900; aliphatic 47.63 polyisocyanate resin based on HDI BuAc/MPA/xylene (1/1/1) 35.70 Sum 249.96

(10) In the examples, the abbreviations “BA” and “BuAc” each mean butyl acetate. “MPA” stands for methoxypropyl acetate.

(11) Flow times in seconds (s) were determined with a 4 mm DIN cup in accordance with DIN EN ISO 2431 RT: room temperature (20° C.).

(12) Flow time as a measure for description of the progression of the reaction was monitored directly after mixing and up to a few hours thereafter. The samples according to the invention showed accelerated reaction compared to the uncatalysed variant.

(13) The parameters “T1” and “T3” relate to the monitoring of the degree of drying of the coatings applied by doctor blade according to DIN EN ISO 9117-5. The paints were applied to a glass plate with a doctor blade and predried (a) at room temperature (RT, 23° C., 50% rel. humidity) and (b) in a Heraus air circulation oven at 60° C. for 30 min, and then the attainment of the degree of drying was monitored at room temperature (23° C., 50% rel. humidity) over time.

EXAMPLE 1

(14) 30 g of the Sylobead MS 548 substrate containing 6 g (20% by weight) of DBTL (dibutyltin dilaurate) was used. In experiment Nos. 1-1 to 1-4, 250 g of the paint material in each case was passed through a high-speed sieve that contained the supported catalyst material, and was then collected again for the purpose of testing. No. 1-5 is a comparative example without catalysis of the reaction mixture.

(15) The catalyst was released to the paint material in such a way that elevated reactivity and drying rate was apparent even as the fourth portion of the paint material was being passed through:

(16) TABLE-US-00002 No. 1-5 (compar- 1-1 1-2 1-3 1-4 ison) Weight before 250 250 250 250 — passage [g] Flow time [s] .sup. 0 h 25 25 25 25 25 0.5 h >100 58 35 31 25 1.0 h — >100 78 50 25 1.5 h — — >100 100 26 Drying [h] T 1 1 1 2 2 >6 at RT T 3 2 4.5 7 >7 >7 Drying [h] T 1 imme- imme- imme- imme- imme- after 30 min. diate diate diate diate diate at 60° C. T 3 imme- imme- imme- iimme- >6 diate diate diate diate

EXAMPLE 2: COMPARISON OF CONVENTIONALLY CATALYSED PAINT SYSTEMS (NO. 1-3) WITH SUPPORTED CATALYST MATERIAL (NO. 4-6) IN SPRAY APPLICATIONS

(17) Coating Formulations:

(18) TABLE-US-00003 2-1 2-2 2-3 2-4 to 2-6 Component A Setalux D A HS 1272 53.64 53.64 53.64 53.66 (about 72% in BA) Byk 331 0.29 0.29 0.29 0.29 Byk 141 0.14 0.14 0.14 0.14 Tinuvin 292 (50% in BA) 0.57 0.57 0.57 0.58 Tinuvin 384-2 (50% in BA) 0.87 0.87 0.87 0.87 DBTL (1% in BA) 1.73 TIB Kat 216 (1% in BA) 1.73 K-Kat XK 651 (1% in BA) 1.73 BuAc/MPA/xylene (1/1/1) 10.22 10.22 10.22 11.11 Component B Desmodur N 3900 19.20 19.20 19.20 19.21 BuAc/MPA/xylene (1/1/1) 13.33 13.33 13.33 14.14 Sum 100.00 100.00 100.00 100.00

(19) In experiments 2-4 to 2-6, different catalysts were added to 30 g of the Sylobead MS 548 substrate. Experiment 2-4 contained 6 g (20% by weight) of DBTL (dibutyltin dilaurate). Experiment 2-5 contained 6 g (20% by weight) of TIB Kat 216 (dioctyltin dilaurate). Experiment 2-6 contained 6 g (20% by weight) of K-Kat XK 651 (bismuth carboxylate).

(20) Experiments 2-1 to 2-3 were designed as comparative examples (conventional catalysis) for spray application under conventional conditions for automotive clearcoat refinishing.

(21) Experiments 2-4 to 2-6 were each passed through a high-speed sieve containing the supported catalyst material prior to the spray application. Thereafter, the paint material was used to conduct an analogous spray application.

(22) A comparison of the drying properties shows that the inventive systems 2-4 to 2-6 showed much faster drying after application.

(23) TABLE-US-00004 Experiment Drying 2-1 2-2 2-3 2-4 2-5 2-6 30′ - 60° C. T 3 4 h  6 h  5 h  30 min immediate 1 h 35 min 33 min 35 min

(24) Comparison of the optical coating properties and processing time:

(25) TABLE-US-00005 Experiment 2-1 2-3 2-4 2-6 Application immediately after mixing of the paint systems (components A + B) Appearance: Gloss 20° 90 90 90 89 Haze 19 13 16 22 Application 3 h after mixing of the paint systems (components A + B) Appearance: Gloss 20° (ISO 2813) 74 87 90 90 Haze (ASTM D 1003) 220 94 15 17

(26) In the case of application immediately after mixing of components A and B, all paint systems showed good optical properties (high gloss and low haze). In the case of application three hours after mixing, only the inventive systems 2-4 and 2-6 examined showed good optical properties and hence a long processing time.