Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From reactant having at least one -n=c=x group as well as...
Reexamination Certificate
2002-01-11
2003-07-29
Gorr, Rachel (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From reactant having at least one -n=c=x group as well as...
C528S049000, C528S085000, C521S118000, C521S129000, C521S164000
Reexamination Certificate
active
06600001
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to alkylamino oxamides that are derived from the condensation of primary N,N-(dialkylaminoalkyl)amines (or mixtures of primary N,N-(dialkylaminoalkyl)amines) with oxalate esters (or oxalic acid). There is thus provided a class of catalysts containing active hydrogen groups that have unique utility as low odor, non-fugitive catalysts for the preparation of polyurethanes. The use of these catalysts permits the preparation of urethane foams having improved physical properties relative to those obtained using conventional amine catalysts.
2. Description of Related Art
Polyurethane foams are produced by allowing a polyisocyanate to react with a compound containing two or more active hydrogen groups. The active hydrogen-containing compounds are typically polyether or polyester polyols, primary and/or secondary polyetheramines, and water. Two major reactions occur between these reactants during the preparation of polyurethane foam. These reactions must proceed simultaneously and at a competitively balanced rate during the process in order to yield polyurethane foam with desired physical characteristics.
Reaction between the isocyanate and the polyol or polyamine, usually referred to as the gel reaction, leads to the formation of a polymer of high molecular weight. This reaction is predominant in solid polyurethane elastomers and in foams blown exclusively with low boiling point organic compounds such as methylene chloride or pentane. This reaction increases the viscosity of the mixture and generally contributes to crosslink formation when polyfunctional polyols, polyamines or polyisocyanates are used.
The second major reaction occurs between the isocyanate and water. This reaction also adds to urethane polymer growth, and is important for producing carbon dioxide gas, which promotes foaming. As a result, this reaction often is referred to as the blow reaction. Both blow and gel reactions occur in foams blown partially or totally with carbon dioxide gas. In fact, the in situ generation of carbon dioxide by the blow reaction plays an essential part in the preparation of “one-shot”, water blown polyurethane foams. Water-blown polyurethane foams, particularly flexible foams, are produced using either molded or slabstock foam processes.
In order to obtain good urethane foam structure and properties, the gel and blow reactions must proceed simultaneously and at optimum balanced rates. For example, if the carbon dioxide evolution is too rapid in comparison with the gel reaction, the foam tends to collapse. Alternatively, if the gel reaction is too rapid in comparison with the blow reaction generating carbon dioxide, foam rise will be restricted, thus resulting in a high-density foam. Also, poorly balanced crosslinking (gel) reactions will have an adverse effect on foam stability. In practice, the balancing of these two reactions is controlled by the nature of the catalysts used in the process.
Typically, the catalysts used for making polyurethanes are of two general types: tertiary amines (mono and poly) and organo-tin compounds. Organometallic tin catalysts predominantly favor the gelling reaction, while amine catalysts exhibit a more varied range of blow/gel balance. Using tin catalysts in flexible foam formulations also increases the quantity of closed cells contributing to foam tightness. Tertiary amines can be effective as catalysts for both the blow and the chain extension reactions and are often used in combination with the organic tin catalysts. Typical tertiary amine catalysts include bis-(dimethylaminoethyl)ether and triethylenediamine, among others, and typical organometallic compounds are stannous octoate and dibutyltindilaurate.
Most tertiary amines (including those noted above) used for the catalysis of polyurethane foam forming reactions are of the fugitive type. Fugitive amines are so designated because they are not bound to the urethane polymer matrix and, therefore, can leave the matrix under certain conditions. This fugitivity results in the emission of fumes from hot foam in both molded and slabstock foam processes. Airborne amine vapors can be an industrial hygiene problem in foam production plants. A particular effect of the amine vapor is glaucopsia, also known as blue-haze or halovision. It is a temporary disturbance of the clarity of vision. Fugitive amines can also cause problems, such as the fogging of automotive windshields, when they are used in the preparation of fully fabricated interior automotive parts. Many prior art fugitive amines also impart an unacceptably strong amine odor to the polyurethane foam. Because of these issues, there is increasing demand in the industry for low fugitivity, low odor catalysts.
Many approaches have been taken to define amine catalysts with reduced fugitivity. Some examples are given below.
Various active hydrogen containing polyurethane catalysts are described in the article: “Factors Affecting the Discoloration of Vinyl That Has Been Molded Against Urethane Foam”, R. L. Zimmerman and T. L. Austin, Polyurethane World Congress, Sep. 29-Oct. 2, 1997, pp. 693-697, 1987.
U.S. Pat. No. 3,073,787 discloses the use of various propionamide derivatives as polyurethane catalysts.
U.S. Pat. No. 3,234,153 discloses the use of various acetamides as catalysts for the preparation of polyurethanes.
U.S. Pat. No. 3,243,389 discloses a variety of aminourethane and/or aminourea catalysts for the preparation of polyurethane plastics.
U.S. Pat. No. 3,784,599 discloses the use of water-soluble quaternary ammonium phthalocyanine dyestuffs useful in the dyeing art.
U.S. Pat. No. No. 4,007,140 discloses a tertiary amine having the general formula:
wherein X is the residue of an organic acid X(OH)
n
, n being the number of acidic groups present in the acid. The amines are said to be useful as low odor catalysts in the production of polyurethanes.
U.S. Pat. No. 4,049,591 discloses compounds of the formula
where n is 2, R″ is lower alkyl, R is hydrogen or lower alkyl and Y is selected from the group consisting of CN, CONH
2
, CO
2
R′, CONR
2
and COR′ where R′ independently is hydrogen, lower alkyl or aryl. A method of producing a polyurethane by utilizing said above compounds as catalysts in reacting an organic polyisocyanate with an organic polyester polyol or polyether polyol in the presence of said catalyst is also disclosed.
U.S. Pat. No. 4,194,069 discloses N-(3-dimethylaminopropyl)-N′-(3-morpholinopropyl)urea and a method of producing a polyurethane by utilizing this compound as a catalyst in reacting an organic polyisocyanate with an organic polyester polyol or polyether polyol in the presence of said catalyst.
U.S. Pat. No. 4,348,536 discloses compounds and the use thereof in producing polyurethane resins. The compounds correspond to the following formula:
wherein n is an integer of from 1 to 5, R is a C
1
-C
5
alkyl group, Y is a C
1
-C
5
alkyl group or a
and Z is a
where n=0 or 1, X is —O— or
and R′ is an aliphatic group having from 1 to 15 carbon atoms and may contain ester, ether, or amide groups or tertiary nitrogen and, when m=0, R′ may be a hydrogen atom.
U.S. Pat. No. 4,644,017 discloses composite polyisocyanate addition products formed from (1) the reaction product of a compound having at least two isocyanate-reactive hydrogen atoms and a molecular weight of from 400 to 10,000, a polyisocyanate and a catalyst which is a diffusion stable amino alkyl urea having tertiary amino groups and corresponds to the formula
in which R
1
, R
2
, R
3
, R
4
, R
5
, R
6
, R
7
and n each represent specified groups or values and (2) another different material such as polyvinyl chloride, ABS, lacquers and textiles.
U.S. Pat. No. 5,489,618 discloses a process for preparing a polyurethane foam according to the one-shot foaming process by reactions between a polyisocyanate and an active hydrogen-containing component including water and an organic polyol wherein said reactions are conducted in the presence
Dererian Edmond J.
Gerkin Richard M.
Robinson Karena Kaye
Crompton Corporation
Dilworth Michael P.
Gorr Rachel
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