Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
2002-05-06
2003-11-04
Niland, Patrick D. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C428S423100, C524S590000, C524S591000, C524S839000, C524S840000
Reexamination Certificate
active
06642303
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to novel aqueous polyurethane-polyurea dispersions based on polycarbonate polyols and polytetramethylene glycol polyols, a process for their production and their use as coating compositions, in particular for flexible substrates such as textiles and leather.
In the coating of flexible substrates, in particular textiles and leather, solvent-containing systems are increasingly replaced by low-solvent or solvent-free aqueous systems. The properties required of textile and leather coating systems consist above all in a high resistance to chemicals and water, high mechanical resistance and high tensile strength and extensibility. These requirements are largely fulfilled by polyurethane-polyurea dispersions of the prior art, such as are described for example in DE-A 24 46 440, DE-A 25 51 094, DE-A 26 51 505, DE-A 26 51 506, DE-A 26 59 617 and DE-A 28 16 815. The systems cited therein are self-emulsifying due to hydrophilic groups and can be dispersed in water without the aid of external emulsifiers.
Polyurethane-polyurea dispersions, referred to below as PU dispersions, are used today in a growing number of sectors, which means that the resulting coatings have to satisfy very diverse ranges of requirements. Thus for the coating of flexible substrates, for example textiles and leather, in addition to the properties mentioned above, properties such as the attainment of thick deposits in a single coat or the production of stable foams are also desirable. The processing steps in the overall coating process can be rationalized and the associated production costs reduced in this way. Furthermore, properties such as good hydrolysis resistance combined with high folding endurance, scratch resistance and abrasion resistance should also be achieved.
It was an object of the present invention to provide alternative PU dispersions as coating compositions for flexible substrates, which meet the requirements of PU dispersions of the prior art but also display the above-mentioned properties.
It has been found that ionic and/or non-ionic hydrophilic, aqueous PU dispersions based on polycarbonate polyols and polytetramethylene glycol polyols allow coatings with the range of properties mentioned above to be produced on substrates. The coatings according to the invention display improved foaming characteristics, high abrasion resistance and extremely high folding endurance, scratch resistance and hydrolysis resistance.
SUMMARY OF THE INVENTION
The invention relates to an ionic and/or non-ionic hydrophilic, aqueous polyurethane (PU) dispersion containing
A1 a polyisocyanate,
A2 a mixture of a polycarbonate and a polytetramethylene glycol polyol,
A3 optionally a monoalcohol or a monoamine,
A4 a polyol, an amino polyol or a polyamine,
A5 optionally a polyoxyalkylene ether with at least one hydroxyl or amino group, and
A6 optionally an antioxidant and/or a light stabilizer and/or another auxiliary substance and/or an additive.
DETAILED DESCRIPTION OF THE INVENTION
In a preferred embodiment the invention relates to PU dispersions containing
A1. 5 to 30 wt. %, more preferred 10 to 25 wt. % and most preferred 13 to 20 wt. % of a polyisocyanate,
A2. 55 to 87 wt. %, more preferred 60 to 85 wt. % and most preferred 70 to 82 wt. % of a mixture of a polycarbonate and a polytetramethylene glycol polyol,
A3. 0 to 10 wt. % of a monoalcohol or monoamine,
A4. 1 to 20 wt. %, more preferred 1 to 15 wt. % and most preferred 1 to 10 wt. % of a polyol, aminopolyol or polyamine,
A5. 0 to 10 wt. %, more preferred 1 to 10 wt. % and most preferred 1 to 5 wt. %, of a polyoxyalkylene ether with at least one hydroxyl or amino group, and
A6. 0 to 10 wt. %, more preferred 0.5 to 8 wt. % and most preferred 1 to 6 wt. %, of antioxidants and/or light stabilizers and/or other auxiliary substances and additives, whereby the sum of the percentages by weight of components A1 to A6 is 100%.
Suitable diisocyanates (Al) include those having a number average molecular weight of 140 to 400 with aliphatically, cycloaliphatically, araliphatically and/or aromatically bonded isocyanate groups. Examples include 1,4-diisocyanatobutane, 1,6-diisocyanatohexane (HDI), 2-methyl-1,5-diisocyanatopentane, 1,5-diisocyanato-2,2-dimethylpentane, 2,2,4- or 2,4,4-trimethyl-1,6-diisocyanatohexane, 1,10-diisocyanatodecane, 1,3- and 1,4-diisocyanatocyclohexane, 1,3- and 1,4-bis(isocyanatomethyl) cyclohexane, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl cyclohexane (isophorone diisocyanate, IPDI), 4,4′-diisocyanatodi-cyclohexyl methane, 1-isocyanato-1-methyl-4(3)isocyanatomethyl cyclohexane, bis(isocyanatomethyl) norbornane, 1,3- and 1,4-bis(2-isocyanatoprop-2-yl) benzene (TMXDI), 2,4- and 2,6-diisocyanatotoluene (TDI), 2,4′- and 4,4′-diisocyanatodiphenyl methane, 1,5-diisocyanato-naphthaline or any blends of such diisocyanates.
Polyisocyanates or polyisocyanate blends with exclusively aliphatically and/or cycloaliphatically bonded isocyanate groups are preferred. More preferred starting components (A1) include polyisocyanates or polyisocyanate blends based on HDI, IPDI and/or 4,4′-diisocyanatodicyclohexyl methane.
Also suitable as polyisocyanates (A1) are any polyisocyanates produced by modification of simple aliphatic, cycloaliphatic, araliphatic and/or aromatic diisocyanates, based on at least two diisocyanates and having a uretdione, isocyanurate, urethane, allophanate, biuret, imino-oxadiazine dione and/or oxadiazine trione structure, including those described in J. Prakt. Chem. 336 (1994) 185-200, DE-A-1 670 666, DE-A-1 954 093, DE-A-2 414 413, DE-A-2 452 532, DE-A-2 641 380, DE-A-3 700 209, DE-A-3 900 053 and DE-A-3 928 503 or EP-A-0 336 205, EP-A-0 339 396 and EP-A-0 798 299, for example.
Component (A2) of the PU dispersions according to the invention contain a mixture of polycarbonate polyols and polytetramethylene glycol polyols. The proportion of polycarbonate polyols in the mixture is between 20 and 80 wt. %, the proportion of polytetramethylene glycol polyols is between 80 and 20 wt. %. A proportion of 30 to 75 wt. % of polytetramethylene glycol polyols and a proportion of 25 to 70 wt. % of polycarbonate polyols is preferred. A proportion of 35 to 70 wt. % of polytetramethylene glycol polyols and a proportion of 30 to 65 wt. % of polycarbonate polyols is more preferred, with the proviso in each case that the sum of the percentages by weight of polycarbonate and polytetramethylene glycol polyols is 100%.
The number-average molecular weight range of the polymeric polyols (A2) is between 400 and 6000. Suitable polymeric polyols (A2) include polyethers, polycarbonates and polyester carbonates having an OH functionality of at least 1.8 to 4. Polyols in a number-average molecular weight range of 600 to 4000 having an OH functionality of 2 to 3 are preferred. Polyols with average molecular weight ranges of 800 to 2500 are more preferred.
Suitable polycarbonates can be obtained by reaction of carbon acid derivatives, e.g. diphenyl carbonate, dimethyl carbonate or phosgene with diols. Suitable examples of such diols include ethylene glycol, 1,2- and 1,3-propanediol, 1,3- and 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, neopentyl glycol, 1,4-bishydroxymethyl cyclohexane, 2-methyl-1,3-propanediol, 2,2,4-trimethyl pentanediol-1,3, dipropylene glycol, polypropylene glycols, dibutylene glycol, polybutylene glycols, bisphenol A, tetrabromobisphenol A as well as lactone-modified diols. The diol component preferably contains 40 to 100 wt. % hexanediol, preferably 1,6-hexanediol and/or hexanediol derivatives. More preferably the diol component includes examples that in addition to terminal OH groups display ether or ester groups, e.g. products obtained by reaction of 1 mol hexanediol with at least 1 mol, preferably 1 to 2 mol caprolactone according to DE-A 1770245, or by etherification of hexanediol with itself to form dihexylene or trihexylene glycol. The production of such derivatives is known from DE-A 15 70 540, for example. The polyether polycarbonate diols described in DE-A 3717060 can
Hassel Tillmann
Kurek Gerald
Rische Thorsten
Schütze Detlef-Ingo
Urban Jürgen
Bayer Aktiengesellschaft
Gil Joseph C.
Matz Gary F.
Niland Patrick D.
Roy Thomas W.
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