Contact adhesive product based on polyurethane resin, production thereof, and corresponding contact adhesive

Abstract

The invention relates to a contact adhesive product, comprising a substrate and a polyurethane resin, which can be obtained by reacting at least A) an aliphatic polyisocyanate component having an average isocyanate functionality of 1.8 and 2.6, B) a polymeric polyether polyol component, C) an amino-functional chain extender component having at least 2 isocyanate-reactive amino groups, containing at least one amino-functional connection C1), which has no ionic or ionogenic group and/or an amino-functional compound C2), which has ionic or ionogenic groups, D) possibly further hydrophilic components which are different from C2), E) possibly hydroxy-functional compounds having a molecular weight of 62 to 399 mol/g, F) possibly further polymeric polyols which are different from B), G) a compound, which has precisely one isocyanate-reactive group, or a compound, which has more than one isocyanate-reactive group, wherein only one of the isocyanate-reactive groups reacts under the selected reaction conditions with the isocyanate groups present in the reaction mixture, and H) possibly an aliphatic polyisocyanate component having an average isocyanate functionality of >2.6 and 4, wherein the components B) and F) together contain 30 wt % on component F), based on the total mass of the components B) and F). The invention further relates to a method for producing the contact adhesive product, to a special polyurethane resin, and to a contact adhesive comprising said polyurethane resin.

Claims

1. A contact-adhesive product comprising a substrate and a polyurethaneurea obtained by reacting at least A) one aliphatic polyisocyanate component having an average isocyanate functionality of 1.8 and 2.6, B) one polymeric polyetherpolyol component, C) one amino-functional chain extender component having at least 2 isocyanate-reactive amino groups, containing at least one amino-functional compound C1) that does not have any ionic or ionogenic groups and/or an amino-functional compound C2) that has ionic or ionogenic groups, D) optionally further hydrophilizing components different than C2), E) optionally hydroxy-functional compounds having a molecular weight of 62 to 399 mol/g, F) optionally at least one further polymeric polyol different than B), G) one compound having exactly one isocyanate-reactive group or one compound having more than one isocyanate-reactive group, where only one of the isocyanate-reactive groups reacts with the isocyanate groups present in the reaction mixture under the reaction conditions chosen, and H) optionally one aliphatic polyisocyanate component having an average isocyanate functionality of >2.6 and 4, wherein components B) and F) together contain 30% by weight of component F), based on the total mass of components B) and F).

2. The product as claimed in claim 1, characterized in that component A) is isophorone diisocyanate and/or hexamethylene diisocyanate.

3. The product as claimed in claim 1, characterized in that component B) contains or consists of poly(tetramethylene glycol) polyetherpolyols (such as (HO(CH.sub.2CH.sub.2CH.sub.2CH.sub.2O).sub.xH).

4. The product as claimed in claim 1, characterized in that component B) contains or consists of a mixture of poly(tetramethylene glycol) polyetherpolyols, wherein the poly(tetramethylene glycol) polyetherpolyols differ in their number-average molecular weights.

5. The product as claimed in claim 1, characterized in that component D) comprises nonionically hydrophilizing components.

6. The product as claimed in claim 1, characterized in that component H) is used and the molar ratio of component G) to component H) is 5:1 to 1:5.

7. The product as claimed in claim 1, characterized in that the polyurethaneurea is obtained by preparing isocyanate-functional polyurethane prepolymers a) from components A), B) and optionally D) and/or C2), and optionally compounds E) and/or H), and the free NCO groups thereof are then wholly or partially reacted with the amino-functional chain-extender component C), and also component G) and optionally components D) and H).

8. The product as claimed in claim 1, characterized in that the polyurethaneurea is amorphous and has a Tg25 C., determined by means of dynamic differential calorimetry in accordance with DIN EN 61006, Method A.

9. The product as claimed in claim 1, characterized in that the substrate has a maximum tensile force of 100 to 500 N, determined to DIN EN ISO 13934-1.

10. The product as claimed in claim 1, characterized in that the product is a plaster, a dressing, a tape or a bandage or at least a constituent of these end products.

11. A process for producing a contact-adhesive product as claimed in claim 1, comprising the steps of I) applying the polyurethaneurea to the substrate in the form of an aqueous polyurethaneurea dispersion and II) thermally drying the treated substrate at temperatures 20 C. and 200 C.

12. A polyurethaneurea obtained by reacting at least A) one aliphatic polyisocyanate component having an average isocyanate functionality of 1.8 and 2.6, B) one polymeric polyetherpolyol component, C) one amino-functional chain extender component having at least 2 isocyanate-reactive amino groups, containing at least one amino-functional compound C1) that does not have any ionic or ionogenic groups and/or an amino-functional compound C2) that has ionic or ionogenic groups, D) optionally further hydrophilizing components different than C2), E) optionally hydroxy-functional compounds having a molecular weight of 62 to 399 mol/g, F) optionally further polymeric polyols different than B), G) one compound having exactly one isocyanate-reactive group or one compound having more than one isocyanate-reactive group, where only one of the isocyanate-reactive groups reacts with the isocyanate groups present in the reaction mixture under the reaction conditions chosen, and H) one aliphatic polyisocyanate component having an average isocyanate functionality of >2.6 and 4, wherein components B) and F) together contain 30% by weight of component F), based on the total mass of components B) and F), and components G) and H) are present in a relative molar ratio of 5:1 to 1:5.

13. An adhesive comprising a polyurethaneurea as claimed in claim 12.

14. An object produced by bonding two or more substrates by means of a polyurethaneurea as claimed in claim 12.

15. An aqueous dispersion comprising a polyurethaneurea as claimed in claim 12.

Description

EXAMPLES

(1) Methods:

(2) Unless indicated otherwise, all percentages are based on weight and the total amount or on the total weight of the compositions.

(3) Unless stated otherwise, all analytical measurements relate to measurements at temperatures of 23 C.

(4) Solids contents were ascertained in accordance with DIN EN ISOL 3251 by heating a weighed sample to 105 C. to constant weight. At constant weight, the solids content was calculated by reweighing the sample.

(5) Unless explicitly mentioned otherwise, NCO values were determined by lumetric means to DIN-EN ISO 11909.

(6) The check for free NCO groups was conducted by means of IR spectroscopy (hand at 2260 cm.sup.1).

(7) The viscosities reported were determined by means of rotary viscometry to DIN 53019 at 23 C. with a rotary viscometer from Anton Paar Germany GmbH, Ostfildern, DE (1 Pa s=1 N/m.sup.2*s).

(8) Average particle sizes (the number-average is specified) of the polyurethane dispersions were determined after dilution with deionized water by means of laser correlation spectroscopy (instrument: Malvern Zetasizer 1000, Malvern Inst. Limited).

(9) The pH was measured by the method described in DIN ISO 976 on the undiluted sample.

(10) Glass transition temperature T.sub.g was determined by dynamic differential calorimetry (DSC) in accordance with DIN EN 61006, Method A, using a DSC instrument (Perkin-Elmer Pyris Diamond DSC calorimeter) calibrated with indium and lead for determination of T.sub.g. 10 mg of the substance to be analyzed are weighed into a sealable aluminum crucible, which is sealed. Three directly successive runs of a heating operation from 100 C. to +150 C., at a heating rate of 20 K/min, with subsequent cooling at a cooling rate of 320 K/min are undertaken, and the third heating curve is used to determine the values. T.sub.g is the temperature determined at half the height of a glass transition step.

(11) The air permeability of the substrates in the unstretched state was determined to DIN EN ISO 9237.

(12) The maximum tensile force of the substrates was determined by a tensile strip test according to DIN EN ISO 13934-1.

(13) The stretching range of the substrates was determined by determining the tensile characteristics of the substrates by means of repeated tensile stress between constant extension limits, and the determination of the total extension to DIN 53835 Part 2.

(14) Substances and Abbreviations Used:

(15) TABLE-US-00001 Diaminosulfonate: NH.sub.2CH.sub.2CH.sub.2NHCH.sub.2CH.sub.2SO.sub.3Na (45% in water) PolyTHF 1000 poly(tetramethylene glycol) polyetherdiol having number-average molar mass 1000 g/mol, BASF SE, Ludwigshafen, DE PolyTHF 2000 poly(tetramethylene glycol) polyetherdiol having number-average molar mass 2000 g/mol, BASF SE, Ludwigshafen, DE Water water demineralized by ion exchanger

(16) The isocyanate components used are commercial products from Covestro Deutschland AG, Leverkusen, DE. Further chemicals were purchased from Sigma-Aldrich Chemie GmbH, Taufkirchen, DE. Unless stated otherwise, the raw materials were used without further purification or pretreatment.

(17) Inventive Polyurethaneurea Dispersion 1

(18) 360 g of PolyTHF 1000 and 1680 g of PolyTHF 2000 were heated to 70 C. Subsequently, a mixture of 180.6 g of hexamethylene diisocyanate and 238.7 g of isophorone diisocyanate was added, and the mixture was stirred at 100-115 C. until the NCO value had eone below the theoretical value. The finished prepolymer was dissolved with 4400 g of acetone at 50 C. and then a solution of 19.6 g of ethylenediamine, 86.3 g of diaminosulfonate, 27.9 g of diethanolamine and 380 g of water was metered in. The mixture was stirred for a further 15 min. This was followed by dispersion by addition of 2100 g of water. Subsequently, the solvent was removed by distillation under reduced pressure, and a storage-stable dispersion was obtained; the solids content was adjusted by addition of water.

(19) Solids content: 52%

(20) Particle size (LKS): 292 nm

(21) Viscosity: 440 mPa s

(22) Tg of polyurethaneurea: 78.7 C.

(23) Inventive Polyurethaneurea Dispersion 2

(24) 75 g of PolyTHF 1000 and 350 g of PolyTHF 2000 were heated to 70 C. Subsequently, a mixture of 33.9 g of hexamethylene diisocyanate, 49.7 g of isophorone diisocyanate and 8.7 g of Desmodur N 3300 (HDI trimer having an NCO content of about 21.8% to DIN EN ISO 11 909) was added, and the mixture was stirred at 100-115 C. until the NCO value had gone below the theoretical value. The finished prepolymer was dissolved with 920 g of acetone at 50 C. and then a solution of 3.2 g of ethylenediamine, 12.9 g of diaminosulfonate, 11.7 g of diethanolamine and 145 g of water was metered in. The mixture was stirred for a further 15 min. This was followed by dispersion by addition of 1080 g of water. Subsequently, the solvent was removed by distillation under reduced pressure, and a storage-stable dispersion was obtained; the solids content was adjusted by addition of water.

(25) Solids content: 52%

(26) Particle size (LKS): 307 nm

(27) Viscosity: 105 mPa s

(28) Tg of polyurethaneurea: 78.0 C.

(29) Polyurethaneurea Dispersion C1 (Comparison 1)

(30) 450 g of PolyTHF 1000 and 2100 g of PolyTHF 2000 were heated to 70 C. Subsequently, a mixture of 225.8 g of hexamethylene diisocyanate and 298.4 g of isophorone diisocyanate was added, and the mixture was stirred at 100-115 C. until the NCO value had gone below the theoretical value. The finished prepolymer was dissolved with 5460 g of acetone at 50 C. and then a solution of 29.5 g of ethylenediamine, 143.2 g of diaminosulfonate and 610 g of water was metered in. The mixture was stirred for a further 15 min. This was followed by dispersion by addition of 1880 g of water. Subsequently, the solvent was removed by distillation under reduced pressure, and a storage-stable dispersion was obtained; the solids content was adjusted by addition of water.

(31) Solids content: 56%

(32) Particle size (LKS): 276 nm

(33) Viscosity: 1000 mPas

(34) Tg of polyurethaneurea: 79.1 C.

(35) Polyurethane Dispersion C2 According to U.S. Pat. No. 5,692,937 (Comparision 2)

(36) The polyurethane dispersion described in U.S. Pat. No. 5,692,937 example 1 (column 4 lines 15 to 34) was reworked. This was done using the IPDI and the polyols from Covestro AG, Leverkusen, Del., while all other chemicals were sourced from Sigma-Aldrich Chemie GmbH, Taufkirchen, Del.

(37) The polyurethane dispersions from the comparative examples were prepared in apparatuses and under conditions comparable to those in U.S. Pat. No. 5,692,937 and the inventive examples.

(38) Use Tests:

(39) Materials Used:

(40) Ypsiflex bandage from Holthaus Ref. 12906S: Air permeability in the unstretched state: 5548 f/m2*s, stretching range: 160%, maximum tensile force: 155.9 N;

(41) Ypsifix bandage from Holthaus Ref. 12223

(42) Testing of Contact Tack:

(43) After the polyurethaneurea composition has been applied and dried to a 30 cm-long Ypsifix bandage (Ref. 12223) or Ypsiflex bandage (Ref 12906S), it is bound around a pin such that the windings are one on top of another. After 14 days, the contact adhesion force of the product to itself is examined. This is done by placing two pieces of length 3 cm one on top of the other, using fingers to gently press them together at room temperature for 10 s, and directly thereafter visually ascertaining the detachment characteristics by pulling the two pieces apart. The scale assessment ranges from 1 (no sticking together) to 5 (sticking very firmly together). Contact tack is considered to be sufficient over and above a classification of 3.

Use Example A1 (Inventive)

(44) 97 g of inventive polyurethaneurea dispersion 1 was initially charged together with 3 g of glycerol in a Speedmixer cup. Bubble-free mixing to give a polyurethaneurea composition was effected in the Speedmixer at a speed of 2750 min.sup.1 for 1 minute. For the spray experiment that followed, the Holthaus Ypsiflex gauze bandage (Ref. 12906S) (630 cm.sup.2) (substrate) that was to be wetted was fixed in a rigid frame. The formulation was transferred from the Speedmixer cup into the reservoir of a spray gun (SATA Jet RP Digital). By means of an air pressure of 1.5 bar, the polyurethaneurea composition was distributed in droplet form onto the substrate via a nozzle (diameter 1.6 mm). The substrate was sprayed once from each side. Drying at 100 C. in an air circulation drying cabinet for 10 min was preceded by predrying at RT for 20 min. After drying, the 30 cm-long coated bandage is wound around a pin such that the windings were one on top of another. The coated bandage stuck together only slightly in the wound arrangement, and did not bond even after storage for 14 days. Contact tack was assessed after 14 days and is listed in table 1.

Use Example A2 (Comparison)

(45) 97 g of the comparative polyurethaneurea dispersion C1 was initially charged together with 3 g of glycerol in a Speedmixer cup. Bubble-free mixing to give a polyurethaneurea composition was effected in the Speedmixer at a speed of rotation of 2750 min.sup.1 for 1 minute. For the spray experiment, the Holthaus Ypsiflex gauze bandage (Ref. 12906S) (630 cm.sup.2) (substrate) that was to be wetted was fixed in a rigid frame. The formulation was transferred from the Speedmixer cup into the reservoir of a spray gun (SATA Jet RP Digital). By means of an air pressure of 1.5 bar, the polyurethaneurea composition was distributed in droplet form onto the substrate via a nozzle (diameter 1.6 mm). The substrate was sprayed once from each side. Drying at 100 C. in an air circulation drying cabinet for 10 min was preceded by predrying at RT for 20 min. After drying, the 30 cm-long coated bandage was wound around a pin such that the windings were one on top of another. Contact tack was assessed after 14 days and is listed in table 1.

Use Example A3 (Inventive)

(46) For the spray experiment, the Ypsifix gauze bandage (Ref. 12223) (630 cm.sup.2) (substrate) that was to be wetted was fixed in a rigid frame. 100 g of the untreated inventive polyurethaneurea dispersion 2 were transferred into the reservoir of a spray gun (SATA Jet RP Digital). By means of an air pressure of 1.5 bar, the dispersion was distributed in droplet form onto the substrate via a nozzle (diameter 1.6 mm). The substrate was sprayed once from each side. Drying was effected at 100 C. in air circulation drying cabinet for 60 min. After drying, the 30 cm-long coated bandage was wound around a pin such that the windings were one on top of another. The coated bandage stuck together only slightly in the wound arrangement, and did not bond even after storage for 14 days. Contact tack was assessed after 14 days and is listed in table 1.

Use Example A4 (Inventive)

(47) 180 g of the inventive polyurethaneurea dispersion 1 were blended with 0.9 g of Rheolate 678 by means of a precision glass stirrer (speed: 1100 min.sup.1 and stirring time: 5 min) to give a polyurethaneurea composition. The Ypsiflex bandage (Ref.12906S) (630 cm.sup.2) (substrate) to be wetted was fixed in a stretcher of a Mathis oven. The polyurethaneurea composition produced was applied in the upper part of the fixed textile and then distributed homogeneously by drawing a coating bar over it. The coating bar gap was 100 m. Drying was effected in the Mathis oven at 120 C. for 2 min. The contact tack of the unrolled bandage was tested after 14 days and is listed in table 1.

Use Example A5 (Comparison)

(48) For the spray experiment, the Ypsiflex gauze bandage (Ref. 12906S) (630 cm.sup.2) (substrate) that was to be wetted was fixed in a rigid frame. 100 g of the untreated comparative polyurethaneurea dispersion C2 were transferred into the reservoir of a spray gun (SATA Jet RP Digital). By means of an air pressure of 1.5 bar, the dispersion was distributed in droplet form onto the substrate via a nozzle (diameter 1.6 mm). The substrate was sprayed once from each side. Drying at 100 C. in an air circulation drying cabinet for 10 min was preceded by predrying at RT for 20 min. After drying, the 30 cm-long coated bandage was wound around a pin such that the windings were one on top of another. Contact tack was assessed after 14 days and is listed in table 1.

(49) TABLE-US-00002 TABLE 1 Test of contact tack after 14 days: Example Example A2 A5 After 14 Example (compar- Example Example (compar- days A1 ative) A3 A4 ative) Assessment 3 1 4 3 1-2
Test of Discoloration:

(50) The color values (L, a and b as per CIELab system) were determined on films of layer thickness 100 m that had been produced on 20 cm*10 cm glass plates of thickness 3 mm from Glas & Fenster Engelbrecht GmbH, Leiehlingen (Rhineland), Germany (application with an applicator frame of gap width 200 m and subsequent drying). The measurement of layer thickness was ascertained with a compressed air gauge connected to a display from Heidehain (MT25P) to display the layer thickness. A thickener was added to all formulations for better film formation (0.5% by weight to 100% by weight of dispersion).

(51) The color value was measured in transmission with the Konica Minolta CMS instrument, the color values were calculated to DIN 11664-4, and the measurement geometry was fixed according to DIN 5033-7 with the parameters d/8, D65 and SCi. The b value describes the yellow color of a film. Table 2 lists test results. The measurement was conducted about 10 days after production of the films. The deviation in the thickness of the films was only a maximum of 1%, based on the thickest point in the film.

(52) It is apparent that the b values of the inventive samples have distinctly lower discoloration compared to the comparative samples. Particularly the aliphatic isocyanates, unlike aromatic isocyanates, are not light-sensitive. While aromatic isocyanates show yellow discoloration on exposure to sunlight, aliphatic isocyanates do not show any discoloration at all through UV radiation such as sunlight.

(53) Formulations used for the color measurement:

Use Example A6 ((Inventive), Corresponding to A1 and A4)

(54) 100 g of inventive polyurethaneurea dispersion 1 were initially charged together with 3 g of glycerol and 0.5 g of Rheolate 210 in a Speedmixer cup. Bubble-free mixing to give a polyurethaneurea composition was effected in the Speedmixer at a speed of 2750 min.sup.1 for 1 minute. After application by means of a coating bar, drying at 50 C. for 10 min and at 120 C. for 3 min in an air circulation drying cabinet was preceded by predrying at RT for 20 min.

Use Example A7 ((Comparison), Corresponding to A2)

(55) 100 g of comparative polyurethaneurea dispersion C1 were initially charged together with 3 g of glycerol and 0.5 g of Rheolate 210 in a Speedmixer cup. Bubble-free mixing to give a polyurethaneurea composition was effected in the Speedmixer at a speed of 2750 min.sup.1 for 1 minute. After application by means of a coating bar, drying at 50 C. for 10 min and at 120 C. for 3 min in an air circulation drying cabinet was preceded by predrying at RT for 20 min.

Use Example A8 ((Inventive), Corresponding to A3)

(56) 100 g of inventive polyurethaneurea dispersion 2 were initially charged together with 0.5 g of Rheolate 210 in a Speedmixer cup. Bubble-free mixing to give a polyurethaneurea composition was effected in the Speedmixer at a speed of 2750 min.sup.1 for 1 minute. After application by means of a coating bar, drying at 50 C. for 10 min and at 120 C. for 3 min in an air circulation drying cabinet was preceded by predrying at RT for 20 min.

Use Example A9 ((Comparison), Corresponding to A5)

(57) 100 g of comparative polyurethaneurea dispersion C2 were initially charged together with 0.5 g of Rheolate 210 in a Speedmixer cup. Bubble-free mixing to give a polyurethaneurea composition was effected in the Speedmixer at a speed of 2750 min.sup.1 for 1 minute. After application by means of a coating bar, drying at 50 C. for 10 min and at 120 C. for 3 min in an air circulation drying cabinet was preceded by predrying at RT for 20 min.

(58) TABLE-US-00003 TABLE 2 Measurement of color values: Example A7 Example A9 Example A6 (comparative) Example A8 (comparative) Layer 73 98 87 83 thickness (m) L value 96.6 96.6 96.6 96.4 a value 0.5 0.5 0.5 0.6 b value 0.3 0.2 0.3 1.0