Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Cellular products or processes of preparing a cellular...
Reexamination Certificate
2001-10-10
2003-07-01
Cooney, Jr., John M. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Cellular products or processes of preparing a cellular...
C252S182260, C252S182270, C521S170000, C521S172000, C521S173000, C521S174000
Reexamination Certificate
active
06586490
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to polyol mixtures which are suitable for the preparation of rigid polyurethane foams and comprise addition products of alkylene oxide on aromatic di- or polyamines, and rigid foams prepared with these polyol mixtures.
Rigid foam polyether-polyols conventionally have a viscosity of 2,000 to 15,000 mPas at 25° C., and in exceptional cases base polyols with viscosities of up to 40,000 mPas at 25° C. are also found. Polyols with OH numbers of 350 to 500 are conventionally employed. In their preparation, a starter with active hydrogen atoms, e.g. a polyalcohol, such as sucrose or sorbitol, or a primary or secondary polyamine, e.g. ethylenediamine or toluylenediamine, is as a rule reacted with an alkyl oxide, a basic catalyst being co-used. In the case of amines specifically, a procedure is often followed in which in each case one alkylene oxide per NH group is first added on to the amine. The addition of further alkylene oxide then takes place only after the addition of the basic catalyst, e.g. KOH. As a result of this, the overall process becomes complicated and is slowed down. This is particularly pronounced in the case of the PO-polyethers which are of industrial interest and are started on aromatic amines. Such polyethers have a very favourable influence on thermal conductivities, strength, curing and blowing agent (alkane) solubility.
Polyethers based on aromatic amines in which a maximum of one alkylene oxide, preferably predominantly propylene oxide (PO), is added on per NH group can be prepared in a one-stage process. In spite of their easy accessibility and their economic properties, such products hitherto so far had only a low industrial importance, since such products have too high a viscosity or are solid at room temperature.
EP-A 826 708 discloses polyol mixtures which comprise addition products of alkylene oxides on di- or polyamines containing primary or secondary amino groups and castor oil and/or reaction products of the addition products mentioned with castor oil. The addition products have OH numbers of at least 500. In addition, the polyol mixture can also comprise further compounds which have at least two hydrogen atoms which are reactive towards isocyanates and a molecular weight of 200 to 12,500 g/mol, such as polyether-polyols or polyester-polyols.
SUMMARY OF THE INVENTION
It has now been found that addition products of alkylene oxide on primary and secondary di- and polyamines, a maximum of in each case one alkylene oxide molecule being added on per NH group, have outstanding processing properties if they are mixed with other polyether- or polyester-polyols which have OH numbers of 250 to 500. The addition product is mixed here with a low-viscosity polyol before, during or after the preparation. It is particularly surprising that these short-chain aminic polyols already have an unexpectedly favourable influence on curing and therefore on the mould dwell time of the foams even at a low concentration.
DETAILED DESCRIPTION OF THE INVENTION
The invention thus provides polyol mixtures which comprise a) 5 to 60 wt. %, preferably 10 to 30 wt. % of one or more addition product(s) of alkylene oxide on aromatic di- or polyamine, the molar ratio in the addition product of alkylene oxide to hydrogen atoms bonded to nitrogen in the aromatic di- or polyamine being not more than 1:1, and b) 40 to 95 wt. %, preferably 70 to 90 wt. % of polyols with OH numbers of 250 to 500.
Polyols with OH numbers of 250 to 500 which are preferably employed are polyether-polyols (in particular poly(oxyalkylene) polyols) and polyester-polyols.
The polyether-polyols are prepared by known methods, preferably by base-catalysed polyaddition of alkylene oxides on to polyfunctional starter compounds containing active hydrogen atoms, such as e.g. alcohols or amines. Examples which may be mentioned are: ethylene glycol, diethylene glycol, 1,2-propylene glycol, 1,4-butanediol, hexamethylene glycol, bisphenol A, trimethylolpropane, glycerol, pentaerythritol, sorbitol, sucrose, degraded starch, water, methylamine, ethylamine, propylamine, butylamine, aniline, benzylamine, o- and p-toluidine, &agr;,&bgr;-naphthylamine, ammonia, ethylenediamine, propylenediamine, 1,4-butylenediamine, 1,2-, 1,3-, 1,4-, 1,5- and/or 1,6-hexamethylenediamine, o-, m- and p-phenylenediamine, 2,4- and 2,6-toluylenediamine, 2,2′-, 2,4- and 4,4′-diaminodiphenylmethane and diethylenediamine.
Alkylene oxides which are employed are, preferably, ethylene oxide, propylene oxide, butylene oxide and mixtures thereof. The construction of the polyether chains by alkoxylation can be carried out with only one monomeric epoxide, or it can take place randomly or also in block form with two or three different monomeric epoxides.
Processes for the preparation of such polyether-polyols are described in “Kunststoffhandbuch, volume 7, Polyurethane, in “Reaction Polymers” and e.g. in U.S. Pat. No. 1,922,451, U.S. Pat. No. 2,674,619, U.S. Pat. No. 1,922,459, U.S. Pat. No. 3,190,927 and U.S. Pat. No. 3,346,557.
Methods for the preparation of polyester-polyols are also well-known and are described e.g. in the two abovementioned literature references (“Kunststoffhandbuch, volume 7, Polyurethane”, “Reaction Polymers”). The polyester-polyols are in general prepared by polycondensation of polyfunctional carboxylic acids or derivatives thereof, such as e.g. acid chlorides or anhydrides, with polyfunctional hydroxyl compounds.
Polyfunctional carboxylic acids which can be used are, for example: adipic acid, phthalic acid, isophthalic acid, terephthalic acid, oxalic acid, succinic acid, glutaric acid, azelaic acid, sebacic acid, fumaric acid or maleic acid.
Polyfunctional hydroxyl compounds which can be used are, for example: ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, 1,12-dodecanediol, neopentylglycol, trimethylolpropane, triethylolpropane or glycerol.
The preparation of the polyester-polyols can furthermore also be carried out by ring-opening polymerization of lactones (e.g. caprolactone) with diols and/or triols as starter compounds.
The polyol mixtures according to the invention preferably comprise 30 to 70 wt. %, preferably 40 to 60 wt. % of a polyol with a viscosity of less than 3,000 mPas (25° C.), preferably less than 2,000 mPas (25° C.), based on the total amount of addition product(s) of alkylene oxide on aromatic di- or polyamine.
In another preferred embodiment, the polyol mixtures according to the invention comprise up to 20 wt. %, preferably up to 10 wt. %, based on the total amount of the polyol mixture, of a phthalic acid, terephthalic acid or adipic acid ester with an OH number of 200 to 400, preferably 250 to 300.
From experience, such polyesters, have a very favourable influence on the thermal conductivity, but on the other hand, curing of the foam is as a rule delayed by their addition. Due to the high reserves which the polyol mixtures according to the invention have in respect of curing, such concentrations of aromatic esters can be co-used without the mould dwell time of the foams being adversely influenced.
In another preferred embodiment, the polyol mixtures according to the invention comprise up to 20 wt. %, preferably up to 10 wt. %, based on the total amount of polyol mixture, of a polypropylene glycol with an OH number of 100 to 300.
Ethylene oxide (EO), propylene oxide (PO), butylene oxide, dodecyl oxide or styrene oxide, for example, can be employed as alkylene oxide for the preparation of the addition compounds; propylene oxide is preferably used.
Starter compounds which are employed for the preparation of the addition compounds are aromatic di- or polyamines which contain primary or secondary amino groups, e.g. phenylenediamines, toluylenediamines (2,3-toluylenediamine, 3,4-toluylenediamine, 2,4-toluylenediamine, 2,5-toluylenediamine, 2,6-toluylenediamine or mixtures of the isomers mentioned), diaminodiphenylmethanes (2,2′-diaminodiphenylmethane, 2
Dietrich Karl-Werner
Dietrich Manfred
Heinemann Torsten
Bayer Aktiengesellschaft
Cooney Jr. John M.
Gil Joseph C.
Whalen Lyndanne M.
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