Water-Vapour Permeable Composite Parts

Abstract

The invention relates to water-vapour permeable, flat composite parts consisting of at least two layers, at least one layer being made of a particular wax-containing thermoplastic polyurethane. The invention also relates to the use thereof.

Claims

1. A water vapour-permeable, flat composite component comprising at least two layers, wherein at least one layer comprises a thermoplastic polyurethane comprising a reaction product of component comprising: A) one or more organic diisocyanates; B) one or more components each having two hydroxyl groups and a number-average molecular weight of 60 to 490 g/mol as chain extenders; C) one or more linear aliphatic hydroxyl-terminated polyether polyols each having number-average molecular weights of 500 to 5000 g/mol and a number-average functionality of component C) of 1.8 to 2.5; wherein the molar ratio of the NCO groups in A) to the isocyanate-reactive groups in components B) and C) is 0.9:1 to 1.2:1; wherein the reaction is effected with addition of: G) 0.02% to 3% by weight, based on the overall weight of the thermoplastic polyurethane, of at least one component selected from the group consisting of: i) maleic anhydride-grafted polyolefins; ii) diesters of branched diols which may contain further hydroxyl groups with mixtures of linear or branched, saturated or unsaturated mono- and dicarboxylic acids; iii) mixtures of salts of linear or branched, saturated or unsaturated monocarboxylic acids and diesters of linear or branched, saturated or unsaturated monocarboxylic acids with linear diols; iv) reaction products of alkylenediamines, with 12-hydroxystearic acid; and v) reaction products of alkylenediamines with 12-hydroxystearic acid and one or more linear fatty acids; and wherein the water vapour permeability of the layer of the thermoplastic polyurethane decreases by not more than 10% after ageing at 70 C. over 24 hours.

2. The flat composite component according to claim 1, wherein the diisocyanate A) is selected from the group consisting of: diphenylmethane 4,4-diisocyanate, isophorone diisocyanate, hexamethylene 1,6-diisocyanate, naphthylene 1,5-diisocyanate dicyclohexylmethane 4,4-diisocyanate and a mixture of any thereof.

3. The flat composite component according to claim 1, wherein the chain extender B) is an aliphatic diol chain extender.

4. The flat composite component according to claim 1, wherein the chain extenders B) comprise at least two aliphatic diol chain extenders.

5. The flat composite component according to claim 4, wherein the chain extenders B) comprise at least two compounds selected from the group consisting of: ethanediol, propanediol, butanediol, hexanediol, 1,4-di(beta-hydroxyethyl)hydroquinone, and 1,4-di(beta-hydroxyethyl)bisphenol A).

6. The flat composite component according to claim 1, wherein the polyether polyols in C) comprise one or more compounds selected from the group consisting of: poly(ethylene glycols), poly(1,2-propylene glycols), poly(1,3-propylene glycols), poly(tetramethylene glycols) and polyether polyols formed from ethylene oxide units and propylene oxide units.

7. The flat composite component according to claim 1, wherein the polyester polyols in D) are aliphatic polyester polyols.

8. The flat composite component according to claim 1, wherein the at least one component in G) is present in an amount of 0.02%-1.0% by weight, based on the overall weight of the thermoplastic polyurethane.

9. The flat composite component according to claim 1, wherein the component in G) comprises component (i), and wherein component (i) comprises maleic anhydride-grafted polyethylenes.

10. The flat composite component according to claim 1, wherein the component in G) comprises component (ii), and wherein component (ii) comprises diesters of adipic acid, oleic acid and pentaerythritol.

11. The flat composite component according to claim 1, wherein the component in G) is selected from the group consisting of: mixtures of reaction products of ethylenediamine with stearic acid and of ethylenediamine with 12-hydroxystearic acid; mixtures of reaction products of ethylenediamine with stearic acid and of ethylenediamine with 12-hydroxystearic acid and stearic acid; mixtures of reaction products of ethylenediamine with 12-hydroxystearic acid and of ethylenediamine with 12-hydroxystearic acid and stearic acid; mixtures of reaction products of ethylenediamine with stearic acid and of ethylenediamine with 12-hydroxystearic acid and of ethylenediamine with 12-hydroxystearic acid and stearic acid; and combinations of any of the mixtures thereof.

12. The flat composite component according to claim 1, wherein the component in G) does not comprise a montanic ester.

13. A roofing underlayment or an exterior underlayment comprising the flat composite component according to claim 1.

14. The flat composite component according to claim 1, wherein the reaction components further comprise: D) polyester polyols each having number-average molecular weights of 500-5000 g/mol and a number-average functionality of component D) of 1.8 to 2.5.

15. The flat composite component according to claim 1, wherein the molar ratio of the NCO groups in A) to the isocyanate-reactive groups in components B) and C) is 0.9:1 to 1.2:1.

16. The flat composite component according to claim 15, wherein the molar ratio of the NCO groups in A) to the isocyanate-reactive groups in components B), C), and D) is 0.9:1 to 1.2:1.

17. The flat composite component according to claim 1, wherein the reaction is conducted in the presence of: E) catalysts.

18. The flat composite component according to claim 1, wherein the reaction is with an addition of: F) auxiliaries and/or additives.

19. The flat composite component according to claim 1, wherein component G) is at least one component selected from the group consisting of: ii) diesters of branched diols which may contain further hydroxyl groups with mixtures of linear or branched, saturated or unsaturated mono- and dicarboxylic acids used in a stoichiometric excess; iii) mixtures of salts of linear or branched, saturated or unsaturated monocarboxylic acids and diesters of linear or branched, saturated or unsaturated monocarboxylic acids with linear diols used in a stoichiometric excess; iv) reaction products of ethylenediamine with 12-hydroxystearic acid; and v) reaction products of ethylenediamine with 12-hydroxystearic acid and one or more linear fatty acids.

Description

[0042] The invention is to be illustrated in more detail by the examples which follow.

EXAMPLES

[0043] TPU Preparation

[0044] For experiments 1 to 16, a reaction vessel was initially charged with 100 parts by weight of polytetrahydrofuran (Terathane 2000 (OH number: 56 mg KOH/g, poly(tetrahydrofuran)); BASF SE, Ludwigshafen, DE) having a temperature of 190 C., in which 0.33 part by weight of Irganox 1010 (BASF SE, Ludwigshafen, DE) and 0.4 part by weight of the particular wax 1 to 6 (except for wax 2:0.8 part by weight) had been dissolved. Then 5.5 parts by weight of butane-1,4-diol (BASF SE, Ludwigshafen, DE), 27.8 parts by weight of diphenylmethane 4,4-diisocyanate at 60 C. (Desmodur 44 M; Bayer MaterialScience AG, Leverkusen, DE) and 50 ppm of tin di(2-ethylhexanoate) were added while stirring, and the overall reaction mixture was stirred vigorously for about 30 seconds. Subsequently, the viscous reaction mixture was poured onto a coated metal sheet and heat-treated at 80 C. for a further 30 minutes. The cast sheets obtained were cut and pelletized.

[0045] Comparative examples 17 to 20 were produced in a continuous TPU reaction in a tubular mixer/extruder (Werner/Pfleiderer ZSK 120 extruder) by the known prepolymer method, as described in example 1 of EP-A 571 828: 73.5 parts by weight of polytetrahydrofuran (Terathane 2000 (OH number: 56 mg KOH/g, poly(tetrahydrofuran)); BASF SE, Ludwigshafen, DE), 0.24 part by weight of Irganox 1010 (BASF SE, Ludwigshafen, DE), 0.51 part by weight of Tinuvin 328 (BASF SE, Ludwigshafen, DE), 0.3 part by weight of Tinuvin 622 (BASF SE, Ludwigshafen, DE), 0.01 part by weight of KL3-2049 stabilizer, 0.4 or 0.8 part by weight of wax 1 or 2, 4 parts by weight of butane-1,4-diol (BASF SE, Ludwigshafen, DE), 20.3 parts by weight of diphenylmethane 4,4-diisocyanate (Desmodur 44 M; Bayer MaterialScience AG, Leverkusen, DE) and 250 ppm of tin di(2-ethylhexanoate). The housing temperatures of the 13 housings were 70 C. to 240 C. The speed of the screw was set to 210 rpm. The total metering rate was 990 kg/h. The TPU was extruded as a molten strand, cooled in water and pelletized.

[0046] Waxes used:

[0047] Wax 1=Loxamid 3324 (N,N-ethylenebisstearylamide; Cognis Oleochemicals GmbH, Dsseldorf, DE)

[0048] Wax 2=Licowax E (montanic esters (C24-C34, dihydric alcohol); Clamant, Frankfurt, DE)

[0049] Wax 3=Licolub FA6 (amide wax formed from ethylenediamine/12-hydroxystearic acid/stearic acid; Clariant, Gersthofen, DE)

[0050] Wax 4=Loxiol G78 (calcium soaps and fatty acid esters (acid number <12); Cognis Oleochemicals GmbH, Dsseldorf, DE)

[0051] Wax 5=PU1747 (adipic acid/oleic acid/pentaerythritol ester (acid number <2; OH number 51); Bayer MaterialScience AG, Leverkusen, DE)

[0052] Wax 6=Licocene PEMA4221 (maleic anhydride-grafted polyethylene; Clariant, Frankfurt, DE)

[0053] TPU Film Production

[0054] The pelletized TPU materials 1 to 20 were each melted in a single-shaft extruder (Brabender Plasticorder PL 2100-6 30/25D single-shaft extruder) (metering rate about 3 kg/h; 185-215 C.) and extruded through a slot die to give a flat film in each case.

[0055] Measurement of water vapour permeability (WVP) of the composite component by measuring the WVP of the TPU films used

[0056] The water vapour permeability (WVP) of the films produced was determined by the following two methods:

[0057] A) to ISO 15106-1 (85% air humidity, 23 C., set of conditions D, Goretex standard 2200 g/m.sup.2/d), sample diameter 90 mm,

[0058] B) based on DIN 53122 (storage of the films which have been tensioned and fixed over a 50 ml vessel filled with 40 g of silica gel granules (diameter 1-3 mm, with indicator) which have been baked at 130 C. for 12 h beforehand, over saturated aqueous potassium chloride solution (air humidity about 85%) in a desiccator at room temperature, determination of weight every 2 h until the increase in weight is constant (6-8 h)), sample diameter 46.5 mm.

[0059] To determine the WVP ageing, the films produced were first placed in an oven at 70 C. for 24 h and then the WVP was determined by the methods described above.

TABLE-US-00001 TABLE 1 WVP and WVP after ageing by method A) Film WVP thick- WVP after Wax ness after ageing [pts. Heat approx. WVP ageing [%], WVP Film by wt.] treatment [m] [g/m.sup.2/d] [g/m.sup.2/d] as 100% 1* 1 none 230 245 0.4 2* 1 24 h 70 C. 250 129 53 0.4 3* 2 none 230 210 0.8 4* 2 24 h 70 C. 250 138 66 0.8 5 3 none 250 226 0.4 6 3 24 h 70 C. 260 224 99 0.4 7* none none 200 258 0 8* none 24 h 70 C. 220 268 104 0 *comparative examples

TABLE-US-00002 TABLE 2 WVP and WVP after ageing by method B) Film WVP Wax thick- WVP after No. ness after ageing [pts. Heat approx. WVP ageing [%], WVP Film by wt.] treatment [m] [g/m.sup.2/d] [g/m.sup.2/d] as 100% 9 3 none 60 276 0.4 10 3 24 h 70 C. 60 261 95 0.4 11 4 none 100 176 0.4 12 4 24 h 70 C. 90 179 102 0.4 13 5 none 60 293 0.4 14 5 24 h 70 C. 50 298 102 0.4 15 6 none 70 253 0.4 16 6 24 h 70 C. 70 244 96 0.4 17* 1 none 70 328 0.4 18* 1 24 h 70 C. 70 285 87 0.4 19* 2 none 80 289 0.8 20* 2 24 h 70 C. 80 103 36 0.8 *comparative examples

[0060] The results show that only in the case of use of waxes 3 to 6 used in accordance with the invention did the water vapour permeability of the thermoplastic polyurethane films remain virtually unchanged after ageing at 70 C. over 24 hours. In addition, the wax-free comparative examples 7 and 8, which likewise did not show any drop in water vapour permeability after ageing, demonstrate that the different degrees of loss of water vapour permeability after ageing in the case of the wax-containing examples 1 to 6 and 9 to 20 were caused not by the polymer matrix but by the waxes alone. The wax-free TPUs, however, have distinct disadvantages in terms of producibility and processing characteristics, and are therefore unsuitable for the production of composite components.