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
2002-05-21
2004-04-20
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, C528S053000, C528S054000, C528S073000, C521S128000, C521S129000, C521S164000, C521S166000
Reexamination Certificate
active
06723819
ABSTRACT:
The present invention relates to a catalyst for production of a polyurethane resin such as a flexible polyurethane foam, a semi-rigid polyurethane foam, a rigid polyurethane foam or a polyurethane elastomer, and a method for producing a polyurethane resin employing such a catalyst. More particularly, it relates to a catalyst and a method for producing a polyurethane resin and a polyurethane foam, which do not substantially discharge a volatile amine.
A polyurethane resin is produced by reacting a polyol with a polyisocyanate in the presence of a catalyst and, if necessary, a blowing agent, a surfactant, a cross-linking agent, etc. Heretofore, it has been known to employ various metal compounds or tertiary amine compounds as catalysts for production of such polyurethane resins. These catalysts are industrially used alone or in combination.
Among these catalysts, tertiary amine compounds are particularly excellent in productivity and moldability and thus widely used as tertiary amine catalysts for production of polyurethane resins. They include, for example, conventional compounds such as triethylenediamine, N,N,N′,N′-tetramethyl-1,6-hexanediamine, bis(2-dimethylaminoethyl)ether, N,N,N′,N″,N″-pentamethyldiethylenetriamine, N-methylmorpholine, N-ethylmorpholine and N,N-dimethylethanolamine.
Metal catalysts tend to be poor in productivity and moldability, and in most cases, they are used in combination with tertiary amine catalysts, and they are rarely employed alone.
However, the tertiary amine catalysts will remain in a free form in polyurethane resin products and will gradually be discharged as volatile amines, whereby various problems will be brought about. For example, a volatile amine discharged from a polyurethane foam in the interior of an automobile creates an odor problem. Further, in recent years, there has been a so-called fogging problem, such that a volatile component in a polyurethane foam will deposit on a window glass of an automobile thereby to bring about fogging of the window glass and thereby to reduce the commercial value. In addition to such problems, there is a pollution problem such that a volatile amine discharged from such a polyurethane product will pollute other materials.
As a method for solving such problems caused by the volatile tertiary amine catalysts, it has been proposed to employ an amine catalyst having in its molecule, primary and secondary amino groups or a hydroxyalkyl group which is capable of reacting with a polyisocyanate (JP-A-46-4846, JP-A-59-191743, JP-B-61-31727, JP-B-57-14762). It is said that the above problems can be avoided, since the amine catalyst will be fixed in the polyurethane resin skeleton in the form as reacted with a polyisocyanate.
However, most of such amine catalysts having a reactive group undergo an incomplete reaction, and a small amount thereof will remain in a free form in polyurethane resin products and will gradually be discharged as volatile amines. Further, although they may once react with the polyisocyanate and be fixed in the polyurethane resin skeleton, they will be discharged as free amines in a small amount when the polyurethane products are brought to a high temperature to bring decomposition of bonds. Further, with the amine catalysts having primary and secondary amino groups, curing of the polyurethane resin tends to be inadequate, thereby to bring about a decrease in the productivity, and further, moldability and physical properties of polyurethane products to be produced tend to be inadequate.
Further, as a method for solving such problems caused by the volatile tertiary amine catalysts, it has been proposed to employ an amine catalyst having a ureide group (such as CONH
2
) in its molecule (JP-A-61-85431). It is disclosed that with such an amine catalyst having a ureide group, volatility and odor tend to decrease as compared with an amine catalyst having no such functional group. Further, it is disclosed that the catalyst having a ureide group is fixed in the polyurethane resin skeleton in the form as reacted with a polyisocyanate, whereby the fogging problem may be avoided. However, the amine catalyst having a ureide group usually has a low or modest level of catalytic activity, whereby productivity of the urethane resin tends to be poor.
Further, metal catalysts other than the amine catalysts, such as organic tin compounds, will not bring about the above problems, but by their single use, the productivity, physical properties and moldability tend to be poor, and further, environmental problems due to metals remaining in products have been pointed out.
The present invention has been made in view of the above problems, and its object is to provide a method for producing such a polyurethane resin that substantially no amine is discharged from products, with good productivity and moldability, and a catalyst to be used for the method.
The present inventors have conducted extensive studies to overcome the above problems and as a result, have found that substantially no volatile amine is generated, no decomposition of bonds takes place, and further, a polyurethane resin can be obtained with good moldability and productivity, by using as an amine catalyst in production of a polyurethane resin, a catalyst selected from the group consisting of a catalyst (A) containing an amine compound of the following formula (1):
wherein each of R
1
and R
2
which are independent of each other, is a C
1-4
alkyl group, and A is a C
5-10
straight chain or branched chain alkylene group, which contains one primary amino group and one tertiary amino group in its molecule, the carbon number of the alkylene group between the two amino groups being from 5 to 10; a catalyst (B) containing an amine compound of the following formula (2):
which has a quinuclidine skelton containing a primary amino group in its molecule;
a catalyst (C) containing a urea-addition product of 3-aminoquinuclidine of the following formula (3):
a catalyst (D) containing an amine compound of the following formula (5):
wherein each of R
3
, R
4
and R
5
which are independent of one another, is a hydrogen atom or a C
1-4
alkyl group, R
6
is a hydrogen atom, a functional group of the following formula:
wherein R
7
is a hydrogen atom or a C
1-4
alkyl group, and p is an integer of from 1 to 3, or a 3-aminopropyl group, and an amine compound of the following formula (6):
wherein X is a nitrogen atom or an oxygen atom, each of R
8
and R
9
which are independent of each other, is a methyl group or a functional group of the following formula:
wherein R
10
is a hydrogen atom or a C
1-4
alkyl group, and q is an integer of from 1 to 3, and each of m and n is an integer of from 1 to 2, provided that when X is a nitrogen atom, R
8
and R
9
are not simultaneously methyl groups, and that when X is an oxygen atom, R
9
is a functional group of the following formula:
wherein R
10
is a hydrogen atom or a C
1-4
alkyl group, and q is an integer of from 1 to 3; and
a catalyst (E) containing an amine compound of the following formula (7):
wherein each of R
11
, R
12
and R
13
which are independent of one another, is a hydrogen atom or a C
1-4
straight chain or branched chain alkyl group, and R
14
is a C
1-4
straight chain or branched chain alkylene group. The present invention has been accomplished on the basis of this discovery.
Namely, the present invention provides a method for producing a polyurethane resin, which comprises reacting a polyol with a polyisocyanate in the presence of a catalyst selected from the group consisting of the above catalysts (A), (B), (C), (D) and (E), and a catalyst for production of a polyurethane resin.
Now, the present invention will explained in detail with reference to the preferred embodiments.
In the present invention, the amine compound of the formula (1) contains one primary amino group and one tertiary amino group in its molecule, and the carbon number of the alkylene group between the two amino groups is from 5 to 10. The carbon number is preferably from 5 to 8 in view of the am
Masuda Takahiro
Nakamura Hiroaki
Tamano Yutaka
Gorr Rachel
Tosoh Corporation
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