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
2002-12-03
2004-04-20
Gorr, Rachel (Department: 1711)
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...
C524S796000, C525S131000
Reexamination Certificate
active
06723787
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to solvent-free, two-component, polyurethane reactive compositions (2C-PUR) modified with special soft resins, for the production hydrophobic coatings that have good elongation, withstand cathodic protection and have long term temperature resistance.
BACKGROUND OF THE INVENTION
To protect oil and gas pipelines, and also the ballast tanks of ships, from corrosion, coatings are required that are highly hydrophobic, are impact-resistant, have good elongation and withstand cathodic protection. Fusion bonded epoxide (FBE) systems, applied as a primer (optionally 2 coats) are known for coating pipelines. Here the powder is reacted on the hot pipe. The FBE coating is coated with polyethylene/polypropylene (PE/PP) by the sintering process, or a coating is built up with adhesive, PU foam and polyethylene. PUR systems applied as wet coatings both to the cold pipe or the field joints also known in the prior art. The pre-coated pipes are bent on site before incorporation into the pipeline network.
A disadvantage of the prior art is that the FBE coatings are brittle and do not have either stone impact resistance or elongation. The bending stresses arising when laying pipelines lead to the formation of cracks in the coating and thus the loss of corrosion protection. FBE systems can be applied for repairs on site or to coat field joints only at great cost (higher energy requirement) and with low productivity. EP-Wet systems cannot be used on site below 0° C. The disadvantages of the pure some cases have lower tolerance of cathodic protection. The hydrophilic properties of the 2C-PUR systems require layer thicknesses of >1000 &mgr;m for corrosion protection of pipes and ballast tanks.
An object of the present invention is to provide solvent-free, liquid primers for the corrosion protection of pipes, which
a) have a long term temperature resistance of up to 30° C. and at the same time withstand cathodic protection,
b) have an elongation at break of at least >5% and are impact resistant,
c) provide long term protection even in thinner coats of 600-900 pm because they are more hydrophobic,
d) can be applied both on site and in a workshop, and cure at temperatures below 0° C.,
e) can be used both for the pipe and for the field joints and
f) have a longer pot life (up to 15 minutes) and a longer surface-working time (up to 50 minutes).
These objects may be achieved with the polyurethane reactive compositions of the present invention as described hereinafter.
SUMMARY OF THE INVENTION
The present invention relates to a solvent-free, two-component polyurethane coating composition that is suitable for the production of coatings that have long term resistance to temperatures of to 30° C., have good elongation and withstand cathodic protection, which contains
A) a solvent-free polymer mixture containing
I) 5 to 50 wt. % of a component free from OH groups and containing
a) 0 to 100 wt. % of a chlorinated paraffin or dibutoxybenzene,
b) 0 to 100 wt. % of a di-[phenoxy-alkyl]formal,
c) 0 to 100 wt. % of a polyacrylonitrile,
wherein the percentages of I-a), I-b) and I-c) add up to 100 wt. %, based on the weights of I-a) to I-c), and
II) 50 to 95 wt. % of a component having hydroxyl groups comprising
a) 40 to 100 wt. % of a component which contains hydroxy groups and ether groups, has a functionality of >3.5 and a number average molecular weight of 280 to 1000, and is different from b),
b) 0 to 60 wt. % of a hydroxy-functional polyether polyacrylate and
c) 0 to 60 wt. % of a hydroxy-functional compound other than a) and b),
wherein the wt. % of 11-a) to 11-c) add up to 100 wt. %, based on the weight of component 11) and
B) a polyisocyanate component comprising at least one organic polyisocyanate, wherein the NCO:OH equivalent ratio is 0.8:1 to 1.5:1.
DETAILED DESCRIPTION OF THE INVENTION
In accordance with the present invention component 1) of solvent-free polymer mixture A) preferably contains
d) a mixture of a) and b) wherein the weight ratio of a):b) is 99:1 to 1:99,
e) a mixture of a) and c) wherein the weight ratio of a):c) is 99:1 to 1:99
or
f) a mixture of b) and c) wherein the weight ratio of b):c) is 99:1 to 1:99.
Suitable OH group-free components I-a) include chlorinated paraffins such as Hordaflex®, Types LC and SP, (Hoechst), Cerechlor®, Types 70/42 (ICI), Rishichlor® (Rishiroop), or polychlorodibutoxybenzene (Rishiroop).
Suitable components I-b) include di(phenoxy-ethyl)formal such as Desavin® (Bayer).
Suitable components I-c) include polyacrylonitriles having a average molecular weight of 600 to 3000.
Suitable components II-a), which contain hydroxyl groups, are polyether polyols, which can be obtained by known in known manner by the addition of cyclic ethers (such as ethylene oxide, propylene oxide, styrene oxide, butylene oxide or tetrahydrofuran) to starter molecules (such as polyvalent alcohols, aminoalcohols or amines free from ether groups, which have a number average molecular weight of 280 to 1000, preferably 350 to 700 and more preferably 400 to 500. The functionality of the starter molecules, with regard to the reaction with cyclic ethers, must be ≧3.5, preferably ≧4. Polyethers, which contain at least 50%, preferably at least 90%, based on the weight of the repeating units, of —CH(CH
3
)CH
2
O group, are especially preferred.
Polyvalent alcohols suitable for use as starter molecules include glycerine, trimethylolpropane, butanetriol-(1,2,4), hexanetriol-(1,2,6), bis(trimethylolpropane), pentaerythritol, mannitol or methylglycoside.
Suitable aminoalcohols include 2-aminoethanol, diethanolamine, 3-amino-1-propanol, 1-amino-2-propanol, diisopropanolamine, 2-amino-2-hydroxymethyl-1,3-propanediol and mixtures thereof.
Suitable polyvalent amines include aliphatic or cycloaliphatic amines, such as ethylene diamine, 1,2-diaminopropane, 1,3-diamino-propane, 1,4-diaminobutane, 1,3-diamino-2,2-dimethylpropane, 4,4-diaminodicyclohexyl-methane, isophorone diamine, hexamethylene diamine, and 1,12-dodecane diamine; aromatic amines such as the isomers of toluylene diamine; and mixtures thereof.
Polyhydroxy component II-b), which is optionally present in the binder mixture according to the invention, can be produced e.g. according to EP-A 825210 (U.S. Pat. No. 6,130,285, herein incorporated by reference).
Suitable alcohol components 11-c) have a (number average) molecular weight of 32 to 1000, preferably 32 to 350. Examples include methanol, ethanol, propanol, butanol, hexanol, 2-ethylhexanol, cyclohexanol, stearyl alcohol, ethylene glycol, diethylene glycol, triethylene glycol, propanediol-1,2 and -1,3, dipropylene glycol, tripropylene glycol, butanediol-1,2, -
1,3 -1,4
and -2,3, pentanediol-1,5,3-methylpentanediol-1,5, hexanediol-1,6,2-ethylhexanediol-1,3,2-methylpropenediol-1,3, 2,2-dimethylpropanediol-1,3,2-butyl-2-ethylpropanediol-1,3,2,2,4-trimethylpentanediol-1,3, octanediol-1,8, higher molecular weight &agr;-alkanediols containing 9 to 18 carbon atoms, cyclohexanedimethanol, cyclohexanediol, glycerine, trimethylolpropane, butanetriol-1,2,4, hexanetriol-1,2,6, bis(trimethylolpropane), pentaerythritol, mannitol and methylglycoside are preferred.
The hydroxy polyesters, hydroxy polyester amides, hydroxy polyethers having a functionality of <3.5, polythioether polyols, hydroxy polycarbonates and hydroxy polyacetals having a number average molecular weight of up to 1,000, which are known from polyurethane chemistry, can optionally also be used as component II-c).
Known stabilizers from coatings technology, such as antioxidants and light stabilizers, can optionally be added to polymer mixture A) to further improve the light- and weather stability of the polyether polyacrylates. The binder mixtures according to the invention are preferably used without stabilizers.
Suitable antioxidants include stearically-hindered phenols such as 4-methyl-2,6-di-tert.-butylphenol (BHT) or other substituted phenols, thioethers (e.g. Irganox PS®, Ciba Geigy) or phospites (e.g. Irgaphos®, Ciba Geigy) available from Ciba Geigy under the
Homann Malte
Kolping Karl-Heinz
Schwindt Jürgen
Bayer Aktiengesellschaft
Gil Joseph C.
Gorr Rachel
Matz Gary F.
Roy Thomas W.
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