VISCOELASTIC ELEMENT BASED ON A POLYURETHANE FOAM

Abstract

The present invention relates to a viscoelastic element comprising a polyurethane foam, wherein the polyurethane foam can be obtained by reacting at least one isocyanate-functional prepolymer (V1) in the presence of a special polyurethane urea dispersion (V2), wherein the reaction of the prepolymer (V1) takes place in the presence of the polyurethane urea (V2) with a medium containing isocyanate-reactive groups. The invention also relates to a method for producing the viscoelastic element and to the use thereof.

Claims

1. A viscoelastic element including a polyurethane foam, obtained by reaction of a reaction mixture comprising at least the following components: (V1) an isocyanate-functional prepolymer obtained by reaction of at least the following components: V1A) an aliphatic diisocyanate, and V1B) a di- to hexafunctional polyalkylene oxide having an ethylene oxide content of 50 to 100 mol %, based on a total amount of oxyalkylene groups present; and (V2) a polyurethaneurea dispersion comprising polyurethaneurea, wherein the polyurethaneurea is obtained by reacting a dispersion reaction mixture comprising at least the following components: V2A) an aliphatic polyisocyanate component having an average isocyanate functionality of 1.8 and 2.6, V2B) a polymeric polyether polyol component, V2C) an amino-functional chain extender component having at least 2 isocyanate-reactive amino groups, comprising at least one of an amino-functional compound C1) that does not have any ionic or ionogenic groups and an amino-functional compound C2) that has ionic or ionogenic groups, V2D) optionally an additional hydrophilizing component different than C2), V2E) optionally a hydroxy-functional compound having a molecular weight of 62 to 399 g/mol, V2F) optionally at least one further polymeric polyol different than V2B), V2G) a compound having exactly one isocyanate-reactive group or a compound having more than one isocyanate-reactive group, wherein only one of the isocyanate-reactive groups reacts with isocyanate groups present in the dispersion reaction mixture, and V2H) optionally an aliphatic polyisocyanate component having an average isocyanate functionality of 2.6 and 4, wherein the reaction mixture comprises a medium containing isocyanate-reactive groups.

2. The viscoelastic element as claimed in claim 1, wherein components (V1) and (V2) are present in the reaction mixture at a weight ratio of 5:1 to 1:1, based on a total weight of components (V1) and (V2).

3. The viscoelastic element as claimed in claim 1, wherein the viscoelastic element has at least one of the following properties: i. damping of 0.40 to 0.90, as measured according to DIN EN ISO 3386-1:2015-10; ii. breaking stress within a range from 0.12 MPa to 0.40 MPa, as measured according to DIN EN ISO 527-2; iii. elongation at break within a range from 150% to 300%, as measured according to DIN EN ISO 527-2; iv. water absorption of 1800% (g/g), or preferably of 1700% (g/g), or preferably of 1500 (g/g), based on dry foam weight, as measured according to DIN EN 13726-1; v. water retention of 80%, or preferably of 70%, or preferably of 60% based on a maximum absorption; vi. recovery time of from 2 to 50 seconds after compression of an original volume by 50% (at a pressure of 7 kPa) to at least 90% of the original volume at standard pressure and room temperature; vii. volume within a range from 0.1 cm.sup.3 to 1 m.sup.3; viii. density within a range of 150 to 400 g/l; ix. loss factor 0.140, preferably a loss factor within a range from 0.140 to 0.400, as measured according to DIN EN ISO 6721-1 x. modulus of elasticity based on DIN EN ISO 527-2 within a range from 0.08 MPa to 0.25 MPa, or preferably from 0.08 MPa to 0.2 MPa, or preferably from 0.08 MPa to 0.15 MPa.

4. The viscoelastic element as claimed in claim 1, comprising component V2F), wherein components V2B) and V2F) together contain 30% by weight of component V2F), based on the total mass of components V2B) and V2F).

5. The viscoelastic element as claimed in claim 1, wherein component V2A) comprises at least one of isophorone diisocyanate and hexamethylene diisocyanate.

6. The viscoelastic element as claimed in claim 1, wherein component V2B) comprises a poly(tetramethylene glycol) polyether polyol.

7. The viscoelastic element as claimed in claim 1, wherein component (V1) is an isocyanate-functional prepolymer having a proportion by weight of low molecular weight, aliphatic diisocyanates having a molar mass of 140 to 278 g/mol of 1.0% by weight, based on the prepolymer, obtained by reaction of V1A) a low molecular weight, aliphatic diisocyanate of molar mass from 140 to 278 g/mol, preferably 168 to 258 g/mol; V1B) a di- to hexafunctional polyalkylene oxide of OH number from 22.5 to 112 mg KOH/g and of ethylene oxide content from 50 to 100 mol %, based on the total amount of oxyalkylene groups present; V1C) optionally a heterocyclic 4-membered or 6-membered ring oligomer of low molecular weight, aliphatic diisocyanates having a molar mass of 140 to 278 g/mol, preferably 168 to 258 g/mol; V1D) optionally a catalyst; V1E) optionally an alkali metal salt of an inorganic acid; V1F) optionally a surfactant; V1G) optionally a mono- or polyhydric alcohol; V1H) at least one of the following components: V1H1) one or more of a low molecular weight, aliphatic diisocyanate having a molar mass of 140 to 278 g/mol, preferably 168 to 258 g/mol or a polyisocyanate preparable therefrom having an isocyanate functionality of 2 to 6, V1H2) one or more monofunctional polyalkylene oxides having an OH number of 10 to 250 and an ethylene oxide content of 50 to 100 mol %, based on the total amount of the oxyalkylene groups present, and V1H3) a hydrophilic isocyanate component obtainable by reaction of components V1H1) and V1H2).

8. A process for producing a viscoelastic element, comprising: I) mixing an isocyanate-functional polyurethane prepolymer (V1) with at least one polyurethaneurea dispersion (V2) in the presence of a medium containing isocyanate-reactive groups to obtain a polyurethane prepolymer/medium mixture, the medium preferably being water; II) applying the polyurethane prepolymer/medium mixture from step I) to a substrate; III) curing the polyurethane prepolymer/medium mixture from step II) to obtain the viscoelastic element; and IV) optionally removing the viscoelastic element from the substrate.

9. The process as claimed in claim 8, wherein applying the polyurethane prepolymer/medium mixture to the substrate in step II) is performed within 3 to 90 seconds of completing the mixing in step I).

10. An earplug for insertion into an ear, comprising a viscoelastic element as claimed in claim 1.

11. (canceled)

12. A kit for producing a viscoelastic element, consisting of (V1) an isocyanate-functional polyurethane prepolymer; (V2) a polyurethaneurea dispersion comprising polyurethaneurea.

13. The kit as claimed in claim 12, wherein component (V2) is an aqueous dispersion.

14. The kit as claimed in claim 12, wherein component (V1) is obtained by reaction of at least the following components: V1A) an aliphatic diisocyanate, and V1B) a di- to hexafunctional polyalkylene oxide having an ethylene oxide content of 50 to 100 mol %, based on a total amount of the oxyalkylene groups present.

15. The kit as claimed in claim 12, wherein the polyurethaneurea of the polyurethaneurea dispersion V2) is obtainable by reacting at least V2A) an aliphatic polyisocyanate component having an average isocyanate functionality of 1.8 and 2.6, V2B) a polymeric polyether polyol component, V2C) an amino-functional chain extender component having at least 2 isocyanate-reactive amino groups, comprising at least one of an amino-functional compound C1) that does not have any ionic or ionogenic groups and an amino-functional compound C2) that has ionic or ionogenic groups, V2D) optionally an additional hydrophilizing component different than C2), V2E) optionally a hydroxy-functional compound having a molecular weight of 62 to 399 g/mol, V2F) optionally at least one further polymeric polyol different than V2B), V2G) a compound having exactly one isocyanate-reactive group or a compound having more than one isocyanate-reactive group, wherein only one of the isocyanate-reactive groups reacts with isocyanate groups present in the dispersion reaction mixture, and optionally an aliphatic polyisocyanate component having an average isocyanate functionality of 2.6 and 4.

16-20. (canceled)

Description

EXAMPLE 1 (B1): ADHESIVE-FREE WOUND CONTACT FOAM

[0257] 125 g of Baymedix FP505 (V1), available from Covestro Germany AG, was mixed with 75 g of an aqueous solution of 0.44% by weight of sodium hydrogencarbonate (available from Fluka, Germany), 1.6% by weight of Pluronic PE6800 (available from BASF SE, Germany), 0.13% by weight of citric acid monohydrate (available from ACROS Organics) and 66.6% by weight of Baymedix AD111 (V2) (available from Covestro) with vigorous stirring for 7 s with the aid of a stirrer system having an anchor stirrer blade (Labordissolver 5 green 037 from Pendraulik GmbH) at 930 rpm and then applied in x-y direction to a release paper of the Y 05200 type from Felix Schller Group, Osnabrck, using a squeegee with a 1.5 mm gap. Thereafter, the surface of the reaction mixture extending in x-y direction was covered with a needled variant (including holes having a diameter of 0.1 mm.sup.2 and a hole density of 10 per cm.sup.2) of the same paper.

[0258] The following measurement results were ascertained:

TABLE-US-00001 Test method: Unit Result: Density g/l 277 Absorption % 1080 Retention % 55 Breaking stress MPa 0.19 Elongation at break % 255 Modulus of elasticity MPa 0.094 Recovery time s 13 Loss factor (tan ) at 1 Hz 0.286 Damping (from compression 0.52 hardness)

EXAMPLE 2 (B2) ADHESIVE-FREE WOUND CONTACT FOAM

[0259] 125 g of Baymedix FP505 (V1), available from Covestro Germany AG, was mixed with 50 g of an aqueous solution of 0.66% by weight of sodium hydrogencarbonate (available from Fluka, Germany), 2.4% by weight of Pluronic PE6800 (available from BASF SE, Germany), 0.2% by weight of citric acid monohydrate (available from ACROS Organics) and 50.0% by weight of Baymedix AD111 (V2) (available from Covestro) with vigorous stirring for 7 s with the aid of a stirrer system having an anchor stirrer blade (Labordissolver 5 green 037 from Pendraulik GmbH) at 930 rpm and then applied in x-y direction to a release paper of the Y 05200 type from Felix Schller Group, Osnabrck, using a squeegee with a 1.5 mm gap. Thereafter, the surface of the reaction mixture extending in x-y direction was covered with a needled variant (including holes having a diameter of 0.1 mm.sup.2 and a hole density of 10 per cm.sup.2) of the same paper.

[0260] The following measurement results were ascertained:

TABLE-US-00002 Test method: Unit Result: Density g/l 210 Absorption % 1409 Retention % 46 Breaking stress MPa 220 Elongation at break % 0.14 Modulus of elasticity MPa 0.096 Recovery time s 4 Loss factor (tan ) at 1 Hz 0.187 Damping (from compression 0.47 hardness)

COMPARATIVE EXAMPLE (VB1) (NOT ACCORDING TO THE INVENTION)

[0261] 125 g of Baymedix FP505 (V1), available from Covestro Germany AG, was mixed with 25 g of an aqueous solution of 1.32% by weight of sodium hydrogencarbonate (available from Fluka, Germany), 4.8% by weight of Pluronic PE6800 (available from BASF SE, Germany), 0.4% by weight of citric acid monohydrate (available from ACROS Organics, Belgium) with vigorous stirring for 7 s with the aid of a stirrer system having an anchor stirrer blade (Labordissolver 5 green 037 from Pendraulik GmbH) at 930 rpm and then applied in x-y direction to a release paper of the Y 05200 type from Felix Schller Group, Osnabrck, using a squeegee with a 1.5 mm gap. Thereafter, the surface of the reaction mixture extending in x-y direction was covered with a needled variant (including holes having a diameter of 0.1 mm.sup.2 and a hole density of 10 per cm.sup.2) of the same paper.

TABLE-US-00003 Test method: Unit Result: Density g/l 133 Absorption % 1874 Retention % 71 Breaking stress MPa 0.09 Elongation at break % 129 Modulus of elasticity MPa 0.078 Recovery time s 1 Loss factor (tan ) at 1 Hz 0.137 Damping (from compression 0.35 hardness)

COMPARATIVE EXAMPLE (VB2) (NOT ACCORDING TO THE INVENTION)

[0262] 125 g of prepolymer mixture from patent BMS111012 (Example 1) was mixed with 22.5 g of an aqueous solution of 2.6% by weight of sodium oleate (available from abcr GmbH, Germany), and 55.6% by weight of Baymedix FD10, available from Covestro Deutschland AG, with vigorous stirring for 7 s with the aid of a stirrer system having an anchor stirrer blade (Labordissolver 5 green 037 from Pendraulik GmbH) at 930 rpm and then applied in x-y direction to a release paper of the Y 05200 type from Felix Schller Group, Osnabrck, using a squeegee with a 1.5 mm gap. Thereafter, the surface of the reaction mixture extending in x-y direction was covered with a needled variant as described in (B1) of the same paper.

TABLE-US-00004 Test method: Unit Result: Density g/l not determined (n.d.) Absorption % n.d. Retention % n.d. Breaking stress MPa n.d. Elongation at break % n.d. Modulus of elasticity MPa n.d. Recovery time s 1 Loss factor (tan ) at 1 Hz n.d. Damping (from compression 0.26 hardness)

COMPARATIVE EXAMPLE (VB3) (NOT ACCORDING TO THE INVENTION)

[0263] 125 g of prepolymer mixture from patent BMS111012 (Example 2) was mixed with 55.8 g of an aqueous solution of 1.1% by weight of sodium oleate (available from abcr GmbH, Germany), and 78.5% by weight of Baymedix FD103, available from Covestro Deutschland AG, with vigorous stirring for 7 s with the aid of a stirrer system having an anchor stirrer blade (Labordissolver 5 green 037 from Pendraulik GmbH) at 930 rpm and then applied in x-y direction to a release paper of the Y 05200 type from Felix Schller Group, Osnabrck, using a squeegee with a 1.5 mm gap. Thereafter, the surface of the reaction mixture extending in x-y direction was covered with a needled variant as described in (B1) of the same paper.

TABLE-US-00005 Test method: Unit Result: Density g/l n.d. Absorption % n.d. Retention % n.d. Breaking stress MPa n.d. Elongation at break % n.d. Modulus of elasticity MPa n.d. Recovery time s 1 Loss factor (tan ) at 1 Hz n.d. Damping (from compression 0.26 hardness)