Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Cellular products or processes of preparing a cellular...
Patent
1997-07-15
1998-11-24
Gorr, Rachel
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Cellular products or processes of preparing a cellular...
521131, 25218225, 25218226, 528421, 564443, C08G 1850
Patent
active
058407812
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
It is known to manufacture rigid PUR foams using readily volatile alkanes and hydro-fluoro alkanes as blowing agents. The range of polyols is generally restricted in this case due to the low solubility of the above-mentioned blowing agents in most commercially available polyols and polyol mixtures. There are admittedly some polyol types with good solubility; trimethylolpropane- and ethylenediamine-started polyethers can be mentioned in particular here. In the case of trimethylolpropane ethers the low functionality has a disadvantageous effect on the mould retention time (curing of the foams obtained), while with higher concentrations of ethylenediamine-started polyethers an excessively high inherent activity of the foam formulation is obtained.
DETAILED DESCRIPTION OF THE INVENTION
It has now been found that propylene oxide polyethers started on o-toluylenediamine on the one hand produce foams with satisfactory curing and on the other also possess a sufficiently low inherent activity, so that they can be added in sufficient concentration to the formulation as is necessary for the solubility of alkanes and hydro-fluoro alkanes.
It has also been shown that the o-toluene diamine-started polyethers are distinguished by a relatively low viscosity. In the papers on these polyethers it has furthermore been noted that relatively low-viscosity polyols can be obtained if the toluene diamine is first of all reacted with 3 mol of propylene oxide and then the desired OH number is set after the addition of an alkaline catalyst and further amounts of propylene oxide.
Polyols are thus obtained which are harmoniously attuned as regards solubility in the blowing agents to be used according to the invention, viscosity, inherent activity, influence on the flow properties of the rigid foams and a short mould retention time.
The invention provides polyether polyols possessing tert. amino groups and having an OH number of 300 to 500, preferably 350 to 420, obtainable by the addition of exclusively propylene oxide to o-toluene diamine,
a method for the manufacture of such polyether polyols, characterised in that o-toluene diamine is reacted first of all with 3 mol of propylene oxide and then after the addition of an alkali catalyst with further amounts of propylene oxide, until an OH number of 300 to 500, preferably 350 to 420, has been reached, and
a polyol formulation for rigid polyurethane foams, containing 40 to 80 wt % of the above-mentioned polyether polyols possessing tert. amino groups.
Preferred is polyether polyols with an OH number of 350 to 500 or containing additionally a mixture of sucrose polyether polyols with an OH number of 350 to 500 and phthalic acid ester polyols, agent, blowing agent and as 1,1,1,4,4,4-hexafluoro-butane and/or 1,1,1,3,3-pentafluoropropane as blowing agent.
The invention also relates to the use of the above-mentioned polyol formulations for the manufacture of rigid polyurethane foams by reacting with organic poly-isocyanates, optionally further compounds with at least two hydrogen atoms reactive to isocyanates, optionally in the presence of water, and further blowing agents known per se as well as conventional auxiliaries and additives.
Use is made according to the invention for the manufacture of rigid polyurethane foams of:
1. the above-mentioned polyether polyols possessing tert. amino groups and having an OH number of 300 to 500, preferably 350 to 420, obtainable by the addition of exclusively propylene oxide to o-toluene diamine. Their manufacture takes place e.g. in such a way that o-toluene diamine is reacted first of all with 3 mol of propylene oxide and then after the addition of an alkali catalyst with further amounts of propylene oxide, until an OH number of 300 to 500, preferably 350 to 420, has been reached. For the manufacture of rigid polyurethane foams they are generally used as a polyol formulation in which their content generally comes to 40 to 80 wt %.
The polyol formulations often contain additionally sucrose polyether polyols having an OH n
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patent: 4904707 (1990-02-01), Lunney
patent: 4970018 (1990-11-01), Lunney
patent: 5260347 (1993-11-01), Krueger et al.
patent: 5461084 (1995-10-01), Doerge
patent: 5583197 (1996-12-01), Harrison et al.
Dietrich Karl-Werner
Dietrich Manfred
Klan Walter
Lamberts Wilhelm
Bayer Aktiengesellschaft
Gil Joseph C.
Gorr Rachel
Whalen Lyndanne M.
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