Organic compounds -- part of the class 532-570 series – Organic compounds – Four or more ring nitrogens in the bicyclo ring system
Reexamination Certificate
2001-03-09
2003-02-04
Sergent, Rabon (Department: 1711)
Organic compounds -- part of the class 532-570 series
Organic compounds
Four or more ring nitrogens in the bicyclo ring system
C252S182200, C252S182210, C252S182220, C528S067000, C528S073000, C528S076000, C528S077000, C544S193000, C560S025000, C560S026000, C560S330000, C560S336000, C560S359000, C560S360000
Reexamination Certificate
active
06515125
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to liquid, partially trimerized polyisocyanate compositions. These liquid polyisocyanate products have an NCO group content of from 24 to 40% by weight, and comprise the partial trimerization product of: (A) 20 to 88% by weight of toluene diisocyanate, and (B) 12 to 80% by weight of a polyisocyanate of the diphenylmethane series, with the sum of the %'s by weight of (A) and (B) totalling 100% by weight. This invention also relates to a process for the preparation of these liquid polyisocyanate compositions which contain isocyanurate groups and have an NCO group content of 24 to 40%.
The trimerization of aromatic isocyanates to form polyisocyanurates is well known in the art. U.S. Pat. Nos. 4,743,627 and 4,382,125 both describe the partial trimerization of polymethylene polyphenylene polyisocyanate (p-MDI), having an average functionality of >2.2, to give stable liquid products having relatively high viscosity at 25° C. (i.e., 2000-100,000 mPa.s).
U.S. Pat. No. 4,284,730 relates to the trimerization of monomeric MDI which has been partially converted to carbodiimide/uretonimine, to give stable liquid polyisocyanurate compositions.
U.S. Pat. No. 5,124,370 describes liquid polyisocyanate mixtures containing isocyanurate groups and having an NCO content of 15 to 30% by weight. These mixtures are obtained by partial trimerization of the isocyanate groups of polyisocyanate mixtures of the diphenylmethane series containing 80 to 100% by weight diisocyanate diphenylmethane isomers and 0 to 20% by weight higher ring compounds of the diisocyanate diphenylmethane series.
The trimerization of toluene diisocyanate in a solvent to make a storage stable liquid is described in both U.S. Pat. No. 4,379,905 and DE 19,523,657. These products are disclosed as being suitable as isocyanate components in two-component polyurethane lacquers.
U.S. Pat. No. 4,456,709 describes storage-stable liquid polyisocyanates which have an NCO group content of 36.5 to 45%. These are prepared by mixing 25 to 70 parts of partially trimerized 2,4-TDI with 75 to 30 parts of unmodified 2,4- and/or 2,6-TDI.
Canadian Patent Application 2,113,890 relates to trimer catalyst systems for aliphatic and aromatic isocyanates. The trimer catalyst systems of this earlier application comprise (A) a lithium compound selected from the group consisting of: (i) lithium salts of aliphatic or aromatic monocarboxylic or dicarboxylic acids, (ii) lithium salts of hydroxyl group containing compounds having from 1 to 3 hydroxyl groups per compound, wherein the hydroxyl groups are directly attached to an aromatic ring, and (iii) lithium hydroxide; and (B) an organic compound containing at least one hydroxyl group. These trimer catalyst systems result in partially trimerized isocyanates which additionally can contain a significant amount of urethane groups.
In accordance with the disclosures of U.S. Pat. No. 4,379,905 and DE 19,523,657, it is necessary that a solvent be present in order to form liquid products. Due to the large quantity of solvent present, these products have restricted uses. In particular, these products are clearly designed for use in coatings applications only.
U.S. Pat. No. 4,456,709 requires pure 2,4-toluene diisocyanate in the first step. The process in this reference results in final products having a relatively narrow NCO content and a restricted distribution of oligomers due to the fact that the trimerization must be completed in the first step of the process.
U.S. Pat. Nos. 6,028,158 and 6,063,891 disclose freeze-stable, allophanate-modified toluene diisocyanurates having an NCO group content of about 15 to about 42%. These freeze-stable compositions are prepared by reacting A) toluene diisocyanate, and B) an organic compound containing at least one hydroxyl group, in the presence of a catalytic amount of C) at least one allophanate-trimer catalyst, or an allophanate-trimer catalyst system. These compositions contain both isocyanurate groups and allophanate groups. Also, this patent discloses blends of these allophanate-modified toluene diisocyanurates with polymethylene poly(phenylisocyanates) (i.e. PMDI), wherein the blend has an NCO content of about 16.8 to 41.6%; and urethane prepolymers of these allophanate-modified toluene diisocyanurates, as well as the blends of these with PMDI, which have NCO group contents of from about 14 to about 40%.
U.S. Pat. No. 4,518,761 discloses a process for the preparation of mixed trimers by at least partially trimerizing the isocyanate groups of two isocyanate components with different reactivities (with respect to trimerization) in the presence of a trimerization catalyst, and mixed trimers prepared by this process. The process comprises (a) adding a less reactive isocyanate component to a vessel, (b) trimerizing at least about 0.1% of the isocyanate groups of the less reactive isocyanate component in the presence of a trimerization catalyst, (c) metering the more reactive isocyanate component into the reaction vessel, and optionally, (d) terminating the trimerization reaction at the desired degree of trimerization by thermal decomposition of the trimer catalyst and/or adding a catalyst stopper/poison. It is essential according to the '761 patent, that the two isocyanate components have different reactivities. Thus, it is possible to use an isocyanate having aliphatically bound and/or cycloaliphatically bound isocyanate groups with an isocyanate having aromatically bound isocyanate groups; or to use an isocyanate having aliphatically or cycloaliphatically bound isocyanate groups with an isocyanate having heteroaromatically bound isocyanates groups; etc. Since aliphatic isocyanates give liquid trimer products, this approach allows for the incorporation of an aromatic isocyanate into a trimer product that could be a liquid. It is not, however, disclosed or suggested by U.S. Pat. No. 4,518,761 that two different aromatic isocyanate components can be used to form a liquid product.
Although U.S. Pat. No. 4,772,639 relates to a process for the production of molded polyurethane, it also discloses polyisocyanate mixtures that contain trimer groups. These isocyanates are either (1) mixtures of (i) isophorone diisocyanate and (ii) a polyisocyanate containing isocyanurate groups based on 1,6-diisocyanato-hexane; or (2) mixtures of (i) isophorone diisocyanate and (ii) a polyisocyanate containing isocyanurate groups based on 1,6-diisocyanato-hexane and isophorone diisocyanate.
U.S. Pat. No. 5,798,431 describes a process for the production of polyisocyanates containing isocyanurate groups by catalytically trimerizing a mixture of a) a low molecular weight isocyanate component having aliphatically bound isocyanate groups, an average molecular weight of 128 to 800 and an average NCO functionality of 1.7 to 2.2, and b) a low molecular weight isocyanate component having an aromatically bound isocyanate groups, an average molecular weight of 148 to 800 and an average NCO functionality of 1.7 to 2.2, in the presence of c) an aminosilyl compound. Any excess distillable isocyanate is subsequently removed to form a polyisocyanate having a monomer content of less than 0.7%, based on the weight of polyisocyanate solids. The examples are directed to toluene diisocyanate and hexamethylene diisocyanate.
A process for the preparation of a polyurea resin is disclosed by U.S. Pat. No. 5,319,058. It comprises (A) mixing (a) an aromatic polyamine component which comprises a combination of at least two aromatic polyamine compounds corresponding to specified formulas and (b) an aliphatic polyisocyanate to form a mixture, and (B) heating the mixture to effect the reaction between the amino groups and the isocyanato groups. Suitable polyisocyanates for component (b) comprise (b1) an aliphatic diisocyanate, and (b2) a cyclic trimer of an aliphatic polyisocyanate.
U.S. Pat. No. 5,102,918 describes a process for producing a modified organic polyisocyanate having an isocyanurate ring. This process comprises adding a trimerization catalyst, an organic pho
Kemp, II Hersel T.
Slack William E.
Yonek Kenneth P.
Bayer Corporation
Brown N. Denise
Gil Joseph C.
Sergent Rabon
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