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
2001-01-19
2003-03-11
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...
C524S589000, C524S590000, C524S591000, C524S839000, C524S840000
Reexamination Certificate
active
06531536
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to polyisocyanates which contain at least some d-limonene as an additive.
BACKGROUND OF THE INVENTION
The use of isocyanate-based coatings, and particularly emulsifiable and emulsified isocyanate coatings are known. In the case of isocyanate-reactive coatings, water presents a problem in that the isocyanate groups react with water. The prior art has suggested the use of emulsifiable adducts which are the reaction products of polyisocyanates and hydroxy functional polyethers, to overcome the problem. These adducts have isocyanate functionality to assist in crosslinking of the water based coating and sufficient hydrophilic character to keep the water based coating composition dispersed in an aqueous medium. These adducts, however, tend to react with water to form urea reaction products which reduce the working life of the emulsifiable polyisocyanate. Moreover, exposure of these emulsifiable polyisocyanates to heat can form undesirable polyureas which greatly reduces the pot life of the emulsifiable polyisocyanate.
A further problem with certain prior art coatings, when used to coat, for example, concrete forms, is the tendency of such coatings to bubble. Most concrete surfaces are not smooth, but rather porous and rough. This porosity and surface roughness is typically referred to as “bug holes” or “void pockets”. The bubbling of prior art coatings is typically most pronounced at the “bug holes” or “void pockets”. A need exists for a coating with a suitable working life, which additionally reduces or eliminates bubbling.
SUMMARY OF THE INVENTION
The invention relates to polyisocyanates which employ at least some d-limonene as an additive. It has been surprisingly found that the addition of a small amount of d-limonene to the polyisocyanate results in a coating material with little or no bubbling when applied to a surface. The d-limonene is added to the polyisocyanate, for example by simple hand-mixing, in an effective amount to reduce bubbling in the coating. After d-limonene addition, the polyisocyanate can be combined with a suitable polyisocyanate-reactive composition, for example a polyol, to form the coating mixture. In an aspect of the invention, the d-limonene can be added to the polyisocyanate-reactive composition, rather than adding it to the polyisocyanate. Moreover, d-limonene can be added to both the polyisocyanate and the polyisocyanate-reactive component. Typically, the polyisocyanate is mixed with the polyisocyanate-reactive composition in a 50:50 by weight ratio. In an aspect of the invention, the polyisocyanate is an emulsifiable polyisocyanate which is subsequently emulsified. In an aspect of the invention an emulsifiable polyisocyanate that includes an isocyanate, a polyisocyanate derived adduct, and d-limonene is used as a coating material. The adducts are the reaction products of a urethane prepolymer and a capping agent, and contains no residual free —NCO groups. The capping agent is any of methoxypolyoxyethylene monols, polyoxyethylene-polyoxypropylene monols, and mixtures thereof. The urethane prepolymer is the reaction product of a di(or higher)hydroxy functional polyol and an isocyanate. The preferred dihydroxy functional polyol is any of polyoxyethylene glycol and polyoxyethylene polyoxypropylene glycols. Preferably, the methoxypolyoxyethylene monols have a molecular weight of about 350 to about 750, and the polyoxyethylene-polyoxypropylene monols have a molecular weight of about 270 to about 3930.
In yet another aspect, the invention relates to an aqueous emulsion having greatly improved stability. The aqueous emulsion includes emulsifiable polyisocyanate. In one embodiment the emulsifiable polyisocyanate may include an isocyanate, a polyisocyanate derived adduct, and d-limonene. The polyisocyanate derived adduct includes the reaction product of a urethane prepolymer and a capping agent, and is free of residual unreacted —NCO groups. The capping agent may be any of methoxypolyoxyethylene monols, polyoxyethylene-polyoxypropylene monols, and mixtures thereof. The urethane prepolymer is the reaction product of a dihydroxy functional polyol and an isocyanate.
A coating material may be formed by combining together the polyisocyanate or isocyanate emulsion, d-limonene and a suitable polyisocyanate-reactive material. The obtained coating material is a polyisocyanate-derived polymer containing at least some d-limonene therein. Suitable polyisocyanate-reactive materials are well known to those skilled in the art and include, for example, polyols, castor oil, water and combinations thereof. Preferred polyols are polyether polyols. Although the polyisocyanate containing d-limonene can be mixed with any suitable amount of polyisocyanate-reactive material, typically the polyisocyanate containing d-limonene is mixed with the polyisocyanate-reactive material at about a 50:50 ratio, based on weight.
Having summarized the invention, the invention is described in detail below by reference to the detailed description below and the following non-limiting examples.
DETAILED DESCRIPTION OF THE INVENTION
Glossary of Terms and Definitions
1. Carbowax 550 is a methoxypolyoxyethylene monol of the formula CH
3
—(OCH
2
CH
2
)
n
—OH where n has an average number of 12. Carbowax 550 is available from Union Carbide Chemicals and Plastics and has a molecular weight of 550.
2. Castor oil is a trifunctional, low molecular weight fatty ester polyol that has a hydroxyl No. of 164 mg-KOH/g, with a specific gravity at 25° C. of 0.96, available from CasChem Chemical.
3. D-limonene has a chemical structure of C
10
H
16
(1-Methyl-4-(1-methylenyl)cyclohexene), and is an industrial grade d-limonene available from Florida Chemical Company.
4. Jeffol® 3709 is a polyether polyol with a nominal functionality of 2 and a hydroxy value of 30, available from Huntsman Corp.
5. Ucon 75-H-450 is a polyoxyethylene-polyoxypropylene glycol of the formula HO—(CH
2
CH
3
CHO)
m
—(CH
2
CH
2
O)
n
—H and has 75 weight percent of oxyethylene and 25 weight percent oxypropylene groups. Ucon 75-H-450 is available from Union Carbide Chemicals and plastics and has a molecular weight of 980.
6. Rubinate® M is polymeric methane diphenyl diisocyanate that has an isocyanate value of 31.5% and a functionality of 2.7 from Huntsman Polyurethanes.
7. Rubinate® 44 is 4,4′-diphenylmethane diisocyanate that has a %NCO value of 33.5 and a functionality of 2.0, available from Huntsman Polyurethanes.
8. Rubinate® 9457 is 4,4′-diphenylmethane diisocyanate that has a % NCO value of 15.3 and a functionality of 2.4, available from Huntsman Polyurethanes.
9. Rubinol® R-241 is a polyether polyol triol, with a functionality of 3 and a hydroxy value of 240 mg-KOH/g, available from Huntsman Polyurethanes.
10. Rubinol® F-481 is a polyether polyol diol, with a functionality of 2 and a hydroxy value of 30 mg-KOH/g, available from Huntsman Polyurethanes.
11. 33LV is a catalyst available from Air Products.
All molecular weights, unless otherwise specified, are number average.
Materials
Isocyanates
Suitable isocyanates which may be employed include known aliphatic, cycloaliphatic, aromatic and heterocyclic polyisocyanates. Also suitable are polyisocyanates which contain carbodiimide groups, urethane groups, allophanate groups, isocyanurate groups, biuret groups, and urea groups.
Examples of aromatic isocyanates which may be employed include but are not limited to 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-toluene diisocyanate (TDI), 2,6-toluene diisocyanate, diphenyl methane-2,4′-diisocyanate(2,4′MDI), diphenyl methane-4,4′-diisocyanate (4,4′MDI), naphthalene-1,5-diisocyanate, triphenyl methane-4,4′,4″-triisocyanate, polymethylene polyphenylene polyisocyanates and mixtures thereof.
Examples of aliphatic polyisocyanates which may be employed include but are not limited to 2,4-hexahydrotoluene diisocyanate, 2,6-hexahydrotoluene diisocyanate, ethylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate (HDI), 2,4,
Huntsman International LLC
Peffer Nicole
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