POLYURETHANE HYBRID POLYMERS AND PROCESS FOR THE PRODUCTION THEREOF

Abstract

The present invention relates to polyurethane hybrid polymers and to a process for producing same.

Claims

1. A method for preparing polyurethane hybrid polymers, comprising combining a polyisocyanates (A) with a compound (B) bearing isocyanate-reactive groups and optionally with a chain extender and/or a crosslinkers (C) and optionally in the presence of a catalysts (D) and optionally in the presence of an auxiliary and/or an additive (E) in a molar ratio of NCO groups to OH and/or NH groups of 0.8:1 to 3.5:1, wherein i) the polyisocyanate (A) is an NCO prepolymer having an NCO content of 10% to 40% by weight, which is prepared from a polyisocyanate (A) comprising at least one of an aliphatic and an aromatic polyisocyanate and a polyol component (B) comprising at least one of a polystyrene polyol having a number-average molecular weight of >1000 g/mol and a polyacrylonitrile polyol having a number-average molecular weight of >2000 g/mol and having the formula below and prepared as shown below:
2nRCHCH.sub.2H[OR-].sub.mOC(O)RSC(S)SRC(O)O[RO].sub.mH--------->H[OR-].sub.mOC(O)R[CH.sub.2CH(R)].sub.nSC(S)S[CH.sub.2CH(R)].sub.nRC(O)O[RO].sub.mH, wherein R represents C.sub.6H.sub.5 aromatic radical or a CN nitrile radical, n, n, m, and m are each an integer1, and R and R independently are alkylene radicals, and optionally at least one further polyol (B) comprising at least one of a polyester polyol, a polyether polyol, and a polyetherester polyol, and ii) the compound (B) bearing isocyanate-reactive groups comprises at least one of a polyester polyol, a polyether polyol, a polyetherester polyol, and an amino-terminated polyether.

2. A polyurethane hybrid polymer prepared from a polyisocyanate (A) and a compound (B) bearing isocyanate-reactive groups in a molar ratio of NCO groups to OH and/or NH groups of 0.8:1 to 3.5:1 comprising a reaction product of: a) an NCO prepolymer as polyisocyanate (A), b) a compound (B) bearing isocyanate-reactive groups comprising at least one of a polyester polyol, a polyether polyol, a polyetherester polyol, and an amino-terminated polyether, and c) optionally a chain extender and/or a crosslinker (C) in the presence of d) optionally a catalyst (D) e) optionally an auxiliary and/or an additive (E), wherein the NCO prepolymer has an NCO content of 10% to 40% by weight and is prepared from a polyisocyanate (A) comprising at least one of an aliphatic and an aromatic polyisocyanates and a polyol component (B) comprising at least one of a polystyrene polyol having a number-average molecular weight of >1000 g/mol and a polyacrylonitrile polyol having a number-average molecular weight of >2000 g/mol and having the formula below and prepared as shown below:
2nRCHCH.sub.2H[OR].sub.mOC(O)RSC(S)SRC(O)O[RO].sub.mH-------->H[OR-].sub.mOC(O)R[CH.sub.2CH(R)].sub.nSC(S)S[CH.sub.2CH(R)].sub.nRC(O)O[RO].sub.mH, wherein R represents a C.sub.6H.sub.5 aromatic radical or a CN nitrile radical, n, n, m, and m are each an integer1, and R and R independently are alkylene radicals, and optionally a further polyol (B) comprising at least one of a polyester polyol, a polyether polyol, and a polyetherester polyol.

3. (canceled)

Description

EXAMPLES

Raw Materials Used:

[0055]

TABLE-US-00001 KOH purity 98% Sigma-Aldrich Chemie GmbH CS.sub.2 purity 99% Sigma-Aldrich Chemie GmbH 2-Bromopropionic acid purity >99% Sigma Aldrich Chemie GmbH Cr(III)Cl.sub.3 purity 99% Acros Organics Toluene purity 99.8% Sigma-Aldrich Chemie GmbH PO (propylene oxide) purity 99.5% Sigma-Aldrich Chemie GmbH

Preparation of the RAFT Reagent:

[0056] Provision of Potassium Trithiocarbonate (K.sub.2CS.sub.3) and Reaction of K.sub.2CS.sub.3 with 2-Bromopropionic Acid to Form Trithiocarbonate Intermediate Compound I

[0057] Potassium trithiocarbonate was prepared in accordance with the method disclosed in Macromolecules (2015), vol. 45, page 4958. A flask was charged with 1230 ml of deionized water and 215 g of KOH while stirring and then 273 g of carbon disulfide was added and stirring continued.

[0058] To this was added dropwise at room temperature 250 g of 2-bromopropionic acid and stirring was continued for 72 hours. The reaction solution was washed with CH.sub.2Cl.sub.2 and acidified with concentrated HCl, filtered, and dried. Volatiles were removed on a rotary evaporator. The yield of intermediate compound I is 45.32 g or 36% (theoretical: 207.8 g, 0.82 mol).

Propoxylation of Intermediate Compound I to Form RAFT Reagent II

[0059] An autoclave was charged under nitrogen with 18.75 g of intermediate compound I in 120 g of toluene and 0.16 of catalyst CrCl.sub.3. 58 g of propylene oxide was then metered in under a nitrogen atmosphere and the mixture was heated to 80 C. and stirred for 3.5 hours. The temperature was then increased to 100 C. and stirring was continued at this temperature for 6 hours.

[0060] After cooling of the autoclave, the mixture was filtered and evaporated to dryness on a rotary evaporator. The yield was 86%.

[0061] The RAFT reagent II may have, by way of example, the following structure:

H[OCH.sub.2CH(CH.sub.3)].sub.mOC(O)CH(CH)SC(S)SCH(CH.sub.3)C(O)O[CH.sub.2CH(CH.sub.3)O-].sub.mH where m and m1

Reaction of RAFT Reagent II with Styrene to Form ,-Polystyrene Diol III

[0062] A three-necked flask was charged with 19.31 g of RAFT reagent II, 108.5 g of styrene, 521.8 g of dioxane, and 2.58 g of 2,2-azobis(2,4-dimethylvaleronitrile). The atmosphere inside the apparatus was then replaced by nitrogen. The reaction was carried out at 60 C. under nitrogen for 22 hours. At the end of the reaction, the mixture was evaporated to dryness on a rotary evaporator and dried under reduced pressure. The yield was 87.97 g (69%). The number-average molecular weight was 2100 g/mol.

Preparation of Polyurethane-Polystyrene Hybrid Polymers and Polyurethane Polymers Via NCO Prepolymers

Starting Compounds Used:

[0063]

TABLE-US-00002 Polystyrene diol III: number-average molecular weight M.sub.w: 2100 g/mol, glass transition temperature T.sub.g: 40 C., decom- position temperature T.sub.d: 190 C. Catalyst Dabco 33LV from Air Products Polyisocyanate 1 4,4-diphenylmethane diisocyanate having an isocyanate content of 33.6% by weight (Desmodur 44M from Covestro Deutschland AG) Polyisocyanate 2 4,4-diphenylmethane diisocyanate containing oligomeric uretonimines, having an isocyanate content of 29.5% by weight (Desmodur CD-S from Covestro Deutschland AG) Polyether polyol 1 glycerol-started polyether polyol obtained from propylene oxide, having an OH value of 42 mg KOH/g Polyether polyol 2 linear, propylene glycol-started propylene oxide polyether polyol, having an OH value of 56 mg KOH/g Polyether polyol 3 glycerol-started polyether polyol obtained from propylene oxide and ethylene oxide, having an OH value of 35 mg KOH/g Tripropylene glycol Polystyrene diol III was ground in a mortar and added at 80 C. to the polyisocyanate component, causing it to dissolve and react to form the NCO prepolymer.

[0064] The second NCO prepolymer was prepared in the same way using the corresponding liquid polyol mixture.

[0065] The materials and amounts used are given in table 1.

TABLE-US-00003 TABLE 1 Example 1 Example 2 [wt.-%] Comparison [wt.-%] Polystyrene diol III 35.45 Polyether polyol 1 3.0 Polyether polyol 2 20.0 Tripropylene glycol 6.0 Diphenylmethane diisocyanate 58.3 66.0 Polyisocyanate 2 6.25 5.0 Sum 100.0 100.0 Isocyanate content of the 20.0 19.8 prepolymer in [wt.-%] Viscosity at 25 C. in [mPas] 260 650

[0066] The two NCO prepolymers were reacted to form the polyurethane under typical conditions in polyurethane chemistry (room temperature, vigorous stirring).

[0067] The two NCO prepolymers were reacted to form the polyurethane or polyurethane-polystyrene hybrid polymer in the amounts shown in table 2.

TABLE-US-00004 TABLE 2 Example 2 Example 1 Comparison [parts by [parts by weight] weight] Polyether polyol 3 100 100 Catalyst 0.1 0.1 NCO prepolymer from 14.5 example 2 NCO prepolymer from 14.5 example 1 Content of polystyrene diol in [wt.-%] 4.5 end product Compatibility reached after [min] 2 2 Gel time [min] 24 23 Properties of the end product: after 24 hours tack-free tacky Hardness after 15 days Shore A 42 37 Hardness after 21 days Shore A 42 42 DSC TG1 [ C.] 59.7 61.1 Water absorption [wt.-%] 4.1 4.4 Tensile test/elongation at break [%] 104 106 Stress at 100% extension [N/mm.sup.2] 1.12 1.09

[0068] There were no significant differences to begin with during processing. The reaction mixtures had become clear after stirring for two minutes, but the reaction mixture containing the polystyrene diol prepolymer solidified appreciably more swiftly.

[0069] Surprisingly, the end product showed an appreciably lower tendency (approx. 7%) to absorb water, even at a low content (4.5% by weight in the end product) of polystyrene diol, whereas the other physico-mechanical properties were equally good compared to the comparison product.

Production of Test Specimens:

[0070] The catalyst was first intimately mixed with the polyol using an IKA RW20 stirrer for 5 minutes. This mixture was then added at room temperature to the initial charge of the respective prepolymer in a paper cup and gently stirred with a wooden stick. The approx. 80 g mass was transferred to an unheated aluminum mold (992 cm.sup.3) having a removable frame. The reaction mixture was allowed to cure under these conditions.

Test Methods:

[0071]

TABLE-US-00005 NCO content in [wt.-%] in EN ISO 11909: 2007 accordance with Viscosity in [mPas] in DIN 53019-1 (2008) at 25 C. accordance with Hardness in [Shore A] in DIN 53506 accordance with Water absorption in [wt.-%] based on ISO 15512(2016): Round disks with a diameter of 5 cm and a thickness of approx. 1 cm were punched out of the cast plates. These were dried to constant weight for 4 days at 50 C. in a desiccator containing drying agent. The drying agent was then replaced with water. The samples were stored for three days at 50 C. under these conditions, after which the absorption of water was determined as the increase in weight. Tensile/stress measurement DIN 53571 (1986) in [N/mm.sup.2] in accordance with DSC measurement in EN ISO 11357-1 (2009) accordance with Gel time in [min] is the time interval from the start of the mixing process until reaching the gel point. The gel point was determined using the Gel Timer from Gelnorm. Compatibility in [min] is the time taken for the stirred reaction components to be transformed from a turbid emulsion to a clear homogeneous mixture.

[0072] It was surprisingly not possible to prepare polyurethane hybrid polymers by the so-called one-shot method. Even at a processing temperature of 50 C., the polystyrene diol seemingly does not dissolve in a reaction mixture consisting of polyether polyol, catalyst, and diphenylmethane diisocyanate with sufficient rapidity for it to be able to take part in the reaction. However, it was surprisingly found that preparation can be carried out without solvent if preparation is carried out via the prepolymer route.