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
2002-08-10
2004-07-13
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...
C521S164000, C521S167000, C252S182260, C564S505000
Reexamination Certificate
active
06762274
ABSTRACT:
The present invention pertains to low emission polyurethane polymer products based on autocatalytic polyols and to the process for their manufacture.
BACKGROUND OF THE INVENTION
Polyether polyols based on the polymerization of alkylene oxides, and/or polyester polyols, are the major components of a polyurethane system together with isocyanates. These systems generally contain additional components such as cross-linkers, chain extenders, surfactants, cell regulators, stabilizers, antioxidants, flame retardant additives, eventually fillers, and typically catalysts such as tertiary amines and/or organometallic salts.
Organometallic catalysts, such as lead or mercury salts, can raise environmental issues due to leaching upon aging of the polyurethane products. Others, such as tin salts, are often detrimental to polyurethane aging.
The commonly used tertiary amine catalysts give rise to several problems, particularly in flexible, semi-rigid and rigid foam applications. Freshly prepared foams using these catalysts often exhibit the typical odor of the amines and give rise to increased fogging (emission of volatile products).
The presence, or formation, of even traces of tertiary amine catalyst vapors in polyurethane products having vinyl films or polycarbonate sheets exposed thereto can be disadvantageous. Such products commonly appear in automotive interiors as seats, armrests, dashboards or instrument panels, sun visors, door linings, noise insulation parts either under the carpet or in other parts of the car interior or in the engine compartment, as well as in many domestic applications such as shoe soles, cloth interliners, appliance, furniture and bedding. While these materials perform excellently in these applications, they possess a deficiency that has been widely recognized. Specifically, the tertiary amine catalysts present in polyurethane foams have been linked to the staining of the vinyl film and degradation of polycarbonate sheets. This PVC staining and polycarbonate decomposition problems are especially prevalent in environments wherein elevated temperatures exist for long periods of time, such as in automobile interiors, which favor emission of amine vapors.
Various solutions to this problem have been proposed. For instance, U.S. Pat. No. 4,517,313 discloses the use of the reaction product of dimethylaminopropylamine and carbonic acid as a catalyst for use in the manufacture of polyurethane. The use of this catalyst is stated to reduce odor and vinyl staining relative to the use of standard triethylenediamine catalysts. However this amine catalyst cannot match the performance of a standard catalyst such as triethylenediamine in polyurethane curing since it is a much weaker catalyst. EP 176,013 discloses the use of specific aminoalkylurea catalysts in the manufacture of polyurethanes. Use of these catalysts is also said to reduce odor and vinyl staining through the use of relatively high molecular weight amine catalysts. Due to their high molecular weight, these amine catalysts are unable to readily migrate through a polyurethane foam and thus their propensity to produce odors and stain vinyl films is reduced. However, when subjected to elevated temperatures as are commonly encountered in automobile interiors parked outside during summer time, these compounds migrate within a foam to some degree.
Use of amine catalysts which contain a hydrogen isocyanate reactive group such as a hydroxyl or a primary and/or a secondary amine are proposed by catalyst suppliers. One such compound is disclosed in EP 747,407. A reported advantage of the catalyst composition is that they are incorporated into the polyurethane product. However those catalysts usually have to be used at high levels in the polyurethane formulation to compensate for their lack of mobility during the reactions to get normal processing conditions. As a result generally not all of these molecules have time to react with isocyanates and some traces of free amine are typically present in the final product, especially in the case of fast gelling and fast curing systems.
Pre-polymerization of reactive amine catalysts with a polyisocyanate and a polyol is reported in PCT WO 94/02525. These isocyanate-modified amines show comparable or enhanced catalytic activity compared with the corresponding non-modified amine catalysts. However, this process gives handling difficulties such as gel formation and poor storage stability.
Specific crosslinkers are proposed in U.S. Pat. No. 4,963,399 to produce polyurethane foams that exhibit a reduced tendency to stain vinyl films. These crosslinkers cannot be used at levels sufficient to get the desired catalytic activity, since they negatively affect foam processing, due to too fast gelling, and foam properties such as tear strength and elongation at break are detrimentally affected due to a level of crosslinking density which is too high. Such disadvantages would also be present for long chain tertiary aminoalcohol crosslinkers as disclosed in EP 488,219.
Modification of polyols by partial amination has been disclosed in U.S. Pat. No. 3,838,076. While this gives additional reactivity to the polyol, this does not allow adjustment of processing conditions since these aminated functions are rapidly tied in the polymer by reacting with the isocyanate. Hence they give fast initiation of the reactions but subsequently loose most of their catalytic activity and do not provide proper final curing.
Use of specific amine-initiated polyols is proposed in EP 539,819 and in U.S. Pat. No. 5,672,636 as applied in semi-rigid and rigid polyurethane foam applications.
Acid modified polyoxypropyleneamine are used as catalysts in U.S. Pat. No. 5,308,882 but still require the use of an organometallic co-catalyst.
Therefore, there continues to be a need for alternative means to control vinyl staining and polycarbonate decomposition by polyurethane compositions.
There also remains a need to eliminate or reduce the amount of amine catalysts and/or organometallic salts in producing polyurethane products.
It is an object of the present invention to produce polyurethane products containing a reduced level of conventional tertiary amine catalysts, a reduced level of reactive amine catalysts or polyurethane products produced in the absence of such amine catalyst. It an another objective of the present invention to produce polyurethane products containing a reduced level of organometallic catalyst or to produce such products in the absence of organometallic catalysts. With the reduction of the amount of amine and/or organometallic catalysts needed or elimination of such catalysts, the disadvantages associated with such catalysts as given above can be minimized or avoided.
It is a further object of the present invention to provide polyols containing autocatalytic activity so that the industrial manufacturing process of the polyurethane product is not adversely affected and may even be improved by the reduction in the amount of conventional or reactive amine catalysts or in elimination of the amine catalyst, and/or by reduction or elimination of organometallic catalysts.
In another aspect, the use of the autocatalytic polyols of the present invention could reduce the level of amine catalysts to which workers would be exposed in the atmosphere in a manufacturing plant.
SUMMARY OF THE INVENTION
The present invention is a process for the production of a polyurethane product by reaction of a mixture of
(a) at least one organic polyisocyanate with
(b) a polyol composition comprising
(b1) from 0 to 95 percent by weight of a polyol compound having a functionality of 2 to 8 and a hydroxyl number of from 20 to 800 and
(b2) from 5 to 100 percent by weight of at least one polyol compound having a functionality of 1 to 8 and a hydroxyl number of from 20 to 800
wherein the weight percent is based on the total amount of polyol component (b), and (b2) is
(b2a) obtained by alkoxylation of at least one initiator molecule of the formula
H
m
A-(CH
2
)
n
—(R)-(CH
2
)
p
-AH
m
Formula (I)
where n and p are independently in
Casati Francois M.
Elwell Richard J.
Sonney Jean-Marie L.
Storione Antoine
Waddington Simon
Dow Global Technologies Inc.
Gorr Rachel
LandOfFree
Low emission polyurethane polymers made with autocatalytic... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Low emission polyurethane polymers made with autocatalytic..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Low emission polyurethane polymers made with autocatalytic... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3199827