SELF-EXTINGUISHING AND INTUMESCENT FLAME RETARDANT POLYURETHANE ELASTOMER COMPOSITIONS

Abstract

The present invention relates to an elastomeric polyurethane comprising at least a first flame retardant in an amount of 5% to 9% by weight based on the total weight of the elastomeric polyurethane and at least one mineral filler in an amount of 3% to 5% by weight based on the total weight of the elastomeric polyurethane, wherein the at least a first flame retardant is at least one phosphorous comprising polyol, wherein the at least one mineral filler is selected from the group consisting of carbonates, sulfates, silicates, mixtures and hydrated modifications thereof and wherein the total amount of the first flame retardant and the mineral filler is in the range of 10% to 14% by weight, based on the total weight of the elastomeric polyurethane, to a process for the preparation of said elastomeric polyurethane, to the use of these elastomeric polyurethane in offshore applications, mine and quarries applications, pulp and paper applications, shoe soles applications, handling applications, military application, transport application, railway and industrial rolls, industrials tires, electric encapsulation, wheels, rollers, doctor blades, hydro cyclones, sieves, sport tracks, insulating panels, acoustic insulations, wind blades or bumpers, and to offshore applications, mine and quarries applications, pulp and paper applications, shoe soles applications, handling applications, military application, transport application, railway and industrial rolls, industrials tires, electric encapsulation, wheels, rollers, doctor blades, hydro cyclones, sieves, sport tracks, insulating panels, acoustic insulations, wind blades or bumpers comprising such a polyurethane.

Claims

1. An elastomeric polyurethane composition comprising at least a first flame retardant in an amount of 5% to 9% by weight based on the total weight of the elastomeric polyurethane and at least one mineral filler in an amount of >3% to 5% by weight based on the total weight of the elastomeric polyurethane, wherein the first flame retardant is a polyol comprising at least one phosphorous, wherein the mineral filler is selected from the group consisting of carbonates, sulfates, silicates, mixtures and hydrated modifications thereof and wherein the total amount of the first flame retardant and the mineral filler is in the range of 10% to 14% by weight, based on the total weight of the elastomeric polyurethane.

2. The composition of claim 1, wherein the phosphorous comprising polyol corresponds to general formula (3) ##STR00004## wherein R.sub.5, R.sub.6, R.sub.7, R.sub.8 and n have independently of another the following meanings: an integer between 1 and 100, R.sub.5 an alkylene group having 1 to 15 carbon atoms, preferably 2 to 10 carbon atoms, R.sub.6 to R.sub.8 independently of another, identical or different, hydrogen or carbon entities.

3. The composition of claim 1 wherein the mineral filler is selected from the group consisting of carbonates, sulfates, mixtures and hydrated modifications thereof.

4. The composition of claim 1, wherein the composition comprises at least a second flame retardant which is different from the first flame retardant, preferably in an amount of >0.1 to 10% by weight based on the total weight of the elastomeric polyurethane.

5. The composition of claim 1, wherein the composition comprises at least one additional filler, which is different from the mineral filler.

6. The composition of claim 1, wherein the composition is a reaction product of a prepolymer and a chain extender comprising the first flame retardant.

7. The composition of claim 6, wherein the prepolymer is a reaction product of a polyisocyanate and a polyol, and the chain extender is a mixture of a polyol and a flame retardant.

8. The composition of claim 6, wherein the molar ratio of isocyanate reactive groups in the chain extender to isocyanate groups in the prepolymer is 0.7 to 1.3.

9. The composition of claim 7, wherein the stoichiometric ratio of isocyanates groups being present in the at least one polyisocyanate to hydroxyl groups being present in the at least one polyol in the prepolymer is 1.5 to 20.

10. The composition of claim 1, wherein the elastomeric polyurethane has a hardness of 55A to 65A, according to ISO 48-4:2018, or a tensile strength of 5 to 9 Mpa, according to DIN 53504:2017, or a tear strength without nick of 15 to 25 kN/m, according to ISO 34-1:2015, and/or a compression set of less than 20%, sired-according to ISO 815-1:2020.

11. A process for preparing an elastomeric polyurethane comprising the following steps: (A) providing a prepolymer comprising a polyisocyanate and a polyol, (B) Providing a chain extender comprising a polyol, a first flame retardant and a mineral filler and optionally at least a second flame retardant which is different from the first flame retardant or optionally at least one additional filler which is different, and (C) Reacting the prepolymer from step (A) and the chain extender from step (B) to obtain the elastomeric polyurethane, wherein the at least a first flame retardant is a polyol comprising at least one phosphorous, wherein the at least one mineral filler is selected from the group consisting of carbonates, sulfates, silicates, mixtures and hydrated modifications thereof, wherein the first flame retardant in an amount of 5% to polyurethane.

12. The process of claim 11, wherein the steps of the process according to the present invention can either be done by hand or by @ low-pressure dispensing machines.

13-14. (canceled)

15. The composition of claim 5, wherein the additional filler is selected from the group consisting of SiO.sub.2, CaO, MgO, Na.sub.2O, K.sub.2O, B.sub.2O.sub.3, Fe.sub.2O.sub.3, P.sub.2O.sub.5, zirconia, cerium oxide, TiO.sub.2, Al(OH).sub.3, mixtures and hydrated modifications thereof.

16. The composition of claim 5, wherein the additional filler is Al(OH) 3.

17. The composition of claim 3, wherein the mineral filler is selected from the group of Li.sub.2CO.sub.3, Na.sub.2CO.sub.3, K.sub.2CO.sub.3, MgCO.sub.3, CaCO.sub.3, BaCO.sub.3, mixtures and hydrated modifications thereof.

18. The composition of claim 2, wherein n is an integer between 2 and 10.

19. The composition of claim 2, wherein R.sub.5 is an alkylene group having 2 to 10 carbon atoms.

20. The composition of claim 2, wherein R.sub.6 to R.sub.8 are independently of another, identical or different, alkyl, aryl, alkenyl, acyl or hydroxyalkyl carbon entities.

21. The composition of claim 2, wherein R.sub.6 to R.sub.8 are independently of another, identical or different, carbon entities, wherein the number of carbon atoms in each substituent is from 1 to 15.

22. The composition of claim 2, wherein R.sub.6 to R.sub.8 are independently of another, identical or different, carbon entities, wherein the number of carbon atoms in each substituent is from 2 to 10.

Description

EXAMPLES

[0112] Test procedure in respect of Combustion Duration, Droplet Formation and Fire Test

[0113] The test procedure is inspired by standards IEC60695 Nov. 10:1999 (internal method UL94, and NF P 92-503 (21 Nov. 2002)). The principle is based on inflammability of a casted elastomer sample when this sample is submitted to a flame. The duration that is necessary to start flame ignition was measured. Additionally, the possible presence or not of burned droplets that could drop on a cotton, set 30 cm far from the sample, was taken into account.

[0114] A sample of the material to be analyzed was cut into the dimension of 1.3 mm1.3 mm12.7 mm. These cut samples were then hung up at a laboratory stand at a height of 30 cm between the lowest part of the sample and the surface of the table. A piece of white cotton is placed below the sample.

[0115] A torch was set and switched-on once the sample and cotton were placed as described above. One should ensure the torch to provide a blue fame with a flame dimension of 1.9 cm. The distance between the sample and the flame should be equal to 1.0 cm.

[0116] The test is based on the norm NF 92-503 and was run according to the following: [0117] Switch on the torch and the stopwatch. [0118] Put the flame on the inferior board of the sample for 10 seconds and then remove the torch. [0119] Measure the combustion duration. This is the time needed for the full inflammation of the sample. If this duration is superior to 15 seconds, one can conclude the sample has flame-retardant properties. If there is no combustion after the torch removal, thus means the sample is self-extinguishing, which is the optimal goal. [0120] Take also into account if there are droplet and if they burns or not. [0121] Take also into account if the cotton burns or not. [0122] At the end of the test, look at the sample to determine if there is a charcoal crust or not. If a charcoal crust can be observed it means the sample is intumescent. [0123] A good fire test means a combustion duration >15 s (or no combustion), intumescence effect and no droplets appearance and a sheet able to demold

[0124] The fire classes according to NF P92-503 are described in the table below. [0125] M0: non-combustible, non-flammable (self-extinguish) [0126] M1: combustible, non-flammable [0127] M2: combustible, hardly flammable [0128] M3: combustible, slightly flammable [0129] M4: combustible, easily flammable

TABLE-US-00001 Non- combustion Combustion Combustion Non-fire Fire of the of the duration Droplets droplets droplets cotton cotton Fire class <5 s No M0 No M1 Yes X X M1 Yes X X M4 Yes X X M2 Yes X X M4 >5 s No M2 Yes X X M2 Yes X X M4 Yes X X M3 Yes X X M4

[0130] The measurement of the hardness was carried out in accordance with standard ISO 48-4:2018.

Mn Determination:

[0131] The number-average molecular weight (Mn) was determined by gel permeation chromatography (GPC) in tetrahydrofuran at 23 C. The procedure is according to DIN 55672-1: Gel permeation chromatography, Part 1-Tetrahydrofuran as eluent (SECurity GPC System from PSS Polymer Service, flow rate 1.0 ml/min; columns: 2PSS SDV linear M, 8300 mm, 5 m; RID detector). Polystyrene samples of known molar mass are used for calibration. The number-average molecular weight is calculated with software support. Baseline points and evaluation limits are fixed in accordance with DIN 55672 Part 1.

Isocyanate Value:

[0132] Measurements of Isocyanate value (%) were done in accordance with ISO 14896:2009.

TABLE-US-00002 TABLE 1 used raw materials Isocyanate Hydroxyl molecular Commercial value value weight name Supplier Type (%) (mgKOH/g) (g/mol) Functionality Initiator MDI 1806 Covestro 45:55 mixture of 2 dicyclohexylmethane-4,4- and -2,4- diisocyanate POLYETHER Covestro PPG polypropylene 534.3 2 PG L 800 glycol (propylene glycol) MDI CD-S Covestro Carbodiimide- 29.5 2 modified MDI: methylenediphenyl diisocyanate, oligomers HYPERLITE Covestro Polyproylene glycol 21.6 3 PG + POLYOL 1650 styrene acrylonitrile SAN DESMOPHEN Covestro Polypropylene glycol 550.1 2 PG 4011T ARCOL Covestro Polypropylene glycol 27 2 PG POLYOL 1374 SUSTERRA Covestro Propane diol 1474.6 76.1 2 PROPANE DIOL DABCO 33 LV Evonik Catalyst Exolit OP550 Clariant Phosphorus polyol 660 2 Nofia OL1000 FRX Phosphanate 1 Polymers oligomer BRITOMYA V Omya UK Calcium carbonate 100.1 powder BARYTMEHL Venator Baryum sulfate 233.4 901 (EX powder Sachtleben) Aluminium Thermo Aluminium 78 hydroxyde fisher hydroxyde powder

Experimental Part:

Example 1: Manufacturing of the Prepolymer Used for all PUs

[0133] 363 g of methylene diphenyl diisocyanate (MDI), having a specific proportion of 55% by weight of 2,4-MDI and 45% by weight of 4,4-MDI, was stirred at 50 C. under dry nitrogen. 560 g of Carbodiimide-modified MDI was added. 76 g of a polyether glycol based on propylene oxide and propylene glycol (Polyether L800) was also added, and the mixture was stirred for 3 to 6 hours at approximately 80 C. The NCO content was measured and was found around 25.6% by weight.

Example 2: Manufacturing of the Chain Extender Used for all PUs

[0134] A polyol mixture of 406,0 g Hyperlite Polyol 1650 (Covestro Deutschland AG, M 5400 g/mol), 32,1 g of polyol 4011 T (based on trimethylol propane and PO, M 400 g/mol) and 545,4 g of Arcol Polyol 1374 (based on glycerol, ethylene oxide and propylene oxide, M 4200 g/mol) was stirred at room temperature. 15,2 g of Propandiol (SUSTERRA) is incorporated. Then 4,0 of catalyst component (Dabco 33LV from EVONIK) were added.

[0135] While still stirring, flame-retardant additives are added from 4 to 9% by weight to the elastomer. The mixture was stirred for additional time if need, from 0 to 1 hour.

Manufacturing of an Elastomer:

[0136] The chain extender, mineral fillers and the prepolymer were stirred together for 30 seconds to 1 minute. A vacuum was then applied to degas the reaction mixture until bubble free. The mixture was poured into a closed mold with a temperature of 23 C. and cured for 24 hours at room temperature.

TABLE-US-00003 TABLE 2 Manufacturing of the elastomers: Mass of the poyol mixture Amount (different Mass of from the Mass of Mass of Mass of of mass of Additive Amount Mass of flame Exolit calcium baryum aluminium Nofia in of Filler Prepolymer retardant) OP550 carbonate sulfate trioxyde OL1000 No. Additive wt-% Filler in wt-% (in g) (in g) (in g) (in g) (in g) (in g) (in g) C1 100 507.2 C2 Exolit 10% 100 362.4 50 OP550 C3 Exolit 13% 100 324.3 64 OP550 C4 Exolit 17% 100 288.9 77 OP550 C5 CaCO.sub.3 4% 100 507.2 24.3 C6 CaCO.sub.3 6% 100 507.2 36.4 C7 Exolit 10% CaCO.sub.3 3% 100 362.4 50 13.9 OP550 C8 Exolit 5% CaCO.sub.3 3% 100 422.3 28 15.7 OP550 C9 Exolit 5% CaCO.sub.3 4% 100 422.3 28 20.9 OP550 10 Exolit 5% CaCO.sub.3 5% 100 422.3 28 26.1 OP550 11 Exolit 9% CaCO.sub.3 3% 100 362.4 50 18.5 OP550 12 Exolit 9% CaCO.sub.3 4% 100 362.4 50 22.4 OP550 13 Exolit 9% CaCO.sub.3 4% 100 362.4 50 22.4 OP550 14 Exolit 9% CaCO.sub.3 5% 100 362.4 50 27.7 OP550 15 Exolit 9% BaSO4 4% 100 362.4 50 22.4 OP550 C16 Exolit 9% CaCO.sub.3 6% 100 362.4 50 32.4 OP550 C17 Exolit 2% CaCO.sub.3 9% 100 465.9 12 56.6 OP550 C18 Exolit 2% CaCO.sub.3 5% 100 465.9 12 27.7 OP550 C19 Exolit 13% CaCO.sub.3 4% 100 324.3 64 20.9 OP550 20 Exolit 9% CaCO3 + 4% + 4% 100 362.4 50 22.4 22.4 OP550 Al(OH)3 C21 Exolit 5% CaCO3 + 3% + 3% 100 422.3 28 15.7 15.7 OP550 Al(OH)3 22 Exolit 9% + 5% CaCO3 4% 100 362.4 50 22.4 26.7 OP550 + Nofia OL1000 C: comparative example

TABLE-US-00004 TABLE 3 Fire tests results for the manufactured elastomers: Amount Amount Molding Sheet Combustion Droplet Fire No. Additive of Additive Filler of Filler Hardness Temp. Aspect Duration [s] formation Test C1 60 shore A RT OK >60 Yes M4 C2 Exolit 10% 60 shore A RT OK 6 Yes M2 OP550 C3 Exolit 13% 60 shore A RT OK 6 Yes M2 OP550 C4 Exolit 17% 60 shore A RT OK 8.5 Yes M2 OP550 C5 CaCO3 4% 60 shore A RT OK 12.5 Yes M2 C6 CaCO3 6% 60 shore A RT OK 7 Yes M2 C7 Exolit 10% CaCO3 3% 60 shore A RT OK >60 No M1 OP550 C8 Exolit 5% CaCO3 3% 60 shore A RT OK 10 s Yes M2 OP550 C9 Exolit 5% CaCO3 4% 62 shore A RT OK 15 Yes M2 OP550 10 Exolit 5% CaCO3 5% 60 shore A RT OK No No MO0 OP550 combustion 11 Exolit 9% CaCO3 3% 62 shore A RT OK No No M0 OP550 combustion 12 Exolit 9% CaCO3 4% 60 shore A RT OK No No M0 OP550 combustion 13 Exolit 9% CaCO3 4% 60 shore A 50 C. OK No No M0 OP550 combustion 14 Exolit 9% CaCO3 5% 60 shore A RT OK No No M0 OP550 combustion 15 Exolit 9% BaSO4 4% 60 shore A 50 C. OK No No M0 OP550 combustion C16 Exolit 9% CaCO3 6% 60 shore A RT OK 15 Yes M4 OP550 C17 Exolit 2% CaCO3 9% 60 shore A RT OK 20 Yes M4 OP550 C18 Exolit 2% CaCO3 5% 60 shore A RT OK 25 Yes M4 OP550 C19 Exolit 13% CaCO3 4% 60 shore A RT OK 11 Yes M2 OP550 20 Exolit 9% CaCO3 + 4% + 4% 60 shore A RT OK No No M0 OP550 Al(OH)3 combustion C21 Exolit 5% CaCO3 + 3% + 3% 60 shore A RT OK 20 Yes M2 OP550 Al(OH)3 22 Exolit OP550 9% + 5% CaCO3 4% 60 shore A RT OK No No M0 Nofia OL1000 combustion C: comparative example