Method, a compound, and a blowing agent for making plastic foam

Details Method, a compound, and a blowing agent for making plastic foam Method, a compound, and a blowing agent for making plastic foam

1990-01-16

1990-10-30

Foelak, Morton

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Cellular products or processes of preparing a cellular...

252350, 521 98, 521155, C08J 914

Patent

active

049669214

DESCRIPTION:

BRIEF SUMMARY
The present invention relates to a method, a compound and a blowing agent for the production of foamed plastics, primarily of polyurethane.
The widespread production of PU foam products is based on the use of a mixture of a polyol system and a blowing agent embodied by a liquid having a relatively low boiling temperature, this mixture being brought to react with isocyanate to produce a polymerization of the polyol, whereby heat is generated sufficiently to cause the blowing agent to boil and to thereby produce vapour conditioning the formation of blisters or cells in the material.
A blowing agent well suited for this purpose is monofluortrichloromethane, also called Freon 11, CFC-11 or R-11, the boiling point of which is approximately 24.degree. C., i.e. just suitable for a foam production under normal room temperature conditions. A large proportion of the relevant products is used for heat insulation purposes, and to this end it is also important that R-11 has a high molecular weight, as the vapour filling of the cells will hereby contribute to a high insulation capacity.
Thus, through many years the production of PU foam products has been based on the use of the relatively cheap and easily accessible R-11, but as now known it has been found that there are heavy environmental problems connected therewith, as the R-11 seems responsible for a certain destruction of the protective ozone layer surrounding our planet.
On this background huge scientific efforts have been made for finding a practically applicable substitute for R-11, but so far without usable results. There are plenty of proposals from the world of the laboratories, where several presumed useful ingredients have been suggested, but practically all having the important drawback that neither now nor in any near future these ingredients will be accessible in any commercially realistic manner.
The methodic research for an R-11-substiture has, naturally, been concentrated primarily about the group of liquids related to R-11, i.e. the halogenated carbon hydrogens, of which several show the desired high molecular weight. Some of these liquids could be well usable as a blowing agent, even without badly influencing the said ozone layer, but unfortunately with certain unacceptable drawbacks. As an example, methylenechloride having a boiling point of some 47.degree. C. could perhaps be usable, but may be non-healthy. When such beforehand unusable liquids are sorted out from the said relevant group of liquids only very few liquids will be left, and the remaining liquids, unfortunately, suffer from the drawback that their boiling points are either far too high or far too low to be relevant for the required boiling at a temperature reasonably close to normal room temperatures. Thus, the boiling point of R-22 is some -40.degree. C.
It should be mentioned that just R-22 nevertheless has been suggested as a blowing agent long before the recent scientific research based on the said ozone problems. Thus, already in U.S. Pat. No. 3,391,093 it is emphasized that R-22 is advantageous to R-12 in that it is more easily soluble in the polyol, and a good solubility is decisive for the vapour generation conditioning a low density of the foam product. It is evident, however, that R-11 is or has been advantageous to R-12, partly because it is still better soluble and partly because it can be handled at room temperature at ambient pressure.
It has also been suggested to use as a blowing agent various mixtures of the different relevant liquids, e.g. R-11 and R-12 or R-11 and R-22, but this has not led to industrially usable results for mixtures without R-11. In most cases, where R-11 is not used, it is prescribed to use foaming machines, where an initial foaming takes place under the influence of one mixture component already in a delivery nozzle, while the other component is added separately immediately next to the nozzle, viz. such that until the mixing of the components it has been possible to handle the components separately by suitable respective temperature and pressure

REFERENCES:
patent: 4251639 (1981-02-01), Jarre et al.

Affiliated with

Also associated with

Rating

Method, a compound, and a blowing agent for making plastic foam does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Method, a compound, and a blowing agent for making plastic foam, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method, a compound, and a blowing agent for making plastic foam will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-275560