Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Cellular products or processes of preparing a cellular...
Reexamination Certificate
2002-01-25
2003-10-28
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...
C521S130000, C521S159000, C521S170000, C521S172000, C521S173000, C428S423100
Reexamination Certificate
active
06638990
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to polyurethane flexible block foams which are flame-laminable and have high peel strength, a process for their production and the use thereof for textile lamination.
Webs of foam produced from polyurethane foam blocks by cutting processes are often used for lamination with many different kinds of textiles for various applications. This is carried out by a bonding or surface melting process, such as flame lamination. Due to their particular suitability, polyester-polyurethane foams are typically used for conventional flame lamination. The ester groups in the polyol component result in a good hot-melting behavior with optimal setting behavior; and the foams exhibit an exceptionally strong bonding to textiles. Such polyester-polyurethane foam/textile laminates have peel strengths of 18 to 22 N, in accordance with DIN 53 357. Moreover, they exhibit elongations at break of about 300% and tensile strengths of about 200 kPa, and accordingly, permit high laminating speeds. Furthermore, at certain bulk densities such polyester foams are self-extinguishing in accordance with FMVSS 302 (SE). Therefore, polyester foams are mainly used as foamed-plastic film for the lamination process. However, their fogging behavior in accordance with DIN 75 201 is unfavorable. This is due to the method of production of the polyester polyols which results in the presence of fogging-active low-molecular components in the polyester polyols. They also have a high proportion of closed cellular structures.
An alternative is the use of polyether foams. These, however, do not have a satisfactory laminability. Various methods of increasing the laminability of polyether foams have been proposed.
Thus, in EP-A 25 549, the addition of neopentyl glycol hydroxypivalate ester during the production of the foam is proposed. This results in good laminability and a good high-frequency weldability, but high values for the compression set are obtained even at bulk densities which are relatively high for ether foams.
EP-A 35 687 discloses the use of solutions of reaction products of diisocyanates with diprimary diols in high-molecular polyethers having mainly secondary hydroxyl groups for the production of flame-laminable foams. However, the foams thus obtained are not resistant to aging. Thus, for example, a poorer recovery after continuous stress is found. These disadvantages are even more marked at lower bulk densities and when flameproofing agents are added in order to achieve self-extinguishing properties.
U.S. Pat. Nos. 5,891,928 and 5,900,087 describe the addition of aliphatic diols or polymeric diols to polyether foam formulations in order to improve the flame laminability. However, the resulting peel strengths of the laminated parts, at 8 to 14 N, are significantly less than those of the laminated polyester foams, which attain values of 18 to 22 N. Experience shows that a peel strength of approximately 16 N is required for a good adhesion.
It has now been found that, the addition of aromatically modified glycols or aromatically modified ether glycols, it is possible to produce flame-laminable ether foams whose peel strength, tensile strength and elongation at break are comparable with those of polyester foams, and which moreover exhibit the favorable aging and fogging behavior of polyether foams. This is true even in the case of foams which have been made self-extinguishing in compliance with FMVSS 302.
SUMMARY OF THE INVENTION
The invention provides flame-laminable polyether-polyurethane foams, which comprise the reaction product of:
A) at least one polyisocyanate or polyisocyanate prepolymer; with
B) at least one polyether polyol having a functionality of 2 to 6 and a number average molecular weight of 1,000 to 10,000 g/mole;
C) optionally, one or more aliphatic chain extenders having a molecular weight of 62 to 800;
D) at least one aromatic polyol component that is at least bifunctional;
E) a blowing agent comprising water, and optionally, CO
2
, which is preferably present in liquid form, and/or other organic blowing agents;
F) optionally, one or more stabilizers;
G) optionally, one or more activators; and
H) optionally, one or more flameproofing agents and other additives.
The aromatic polyol components that are at least bifunctional, i.e. component D) above, result in flame-laminable polyether polyurethane foams.
The present invention also relates to a process for the production of a flame-laminable polyether-polyurethane foam. This process comprises reacting:
A) at least one polyisocyanate or polyisocyanate prepolymer; with
B) at least one polyether polyol having a functionality of 2 to 6 and a number average molecular weight of 1,000 to 10,000 g/mole;
C) optionally, one or more aliphatic chain extenders having a molecular weight of 62 to 800;
D) at least one aromatic polyol component that is at least bifunctional;
E) a blowing agent comprising water, and optionally, CO
2
, which is preferably present in liquid form, and/or other organic blowing agents;
F) optionally, one or more stabilizers;
G) optionally, one or more activators; and
H) optionally, one or more flameproofing agents and other additives.
The present invention also relates to a process for the production of a composite material comprising laminating a layer of polyether-polyurethane foam with a textile layer.
In the process according to the present invention, organic di- or polyisocyanates or polyisocyanate prepolymers are suitable for component A). Suitable di- or polyisocyanates include, for example, aliphatic, cycloaliphatic, araliphatic, aromatic and heterocyclic polyisocyanates, such as are described in Justus Liebigs Annalen der Chemie, 562 (1949) 75, for example, those corresponding to the formula:
Q(NCO)
n
wherein:
n represents an integer from 2 to 4, preferably 2, and
Q represents an aliphatic hydrocarbon group having 2 to 18 carbon atoms, preferably 6 to 10 carbon atoms, a cycloaliphatic hydrocarbon group having 4 to 15 carbon atoms, preferably 5 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 15 carbon atoms, preferably 6 to 13 carbon atoms, or an araliphatic hydrocarbon group having 8 to 15 carbon atoms, preferably 8 to 13 C atoms.
Polyisocyanates of the type described in U.S. Pat. No. 4,263,408, the disclosure of which is herein incorporated by reference, are preferred. As a rule, the technically readily accessible polyisocyanates are particularly preferred such as, for example, 2,4-and 2,6-tolylene diisocyanate as well any mixtures of these isomers (“TDI”), polyphenyl polymethylene polyisocyanates, as produced by aniline-formaldehyde condensation and subsequent phosgenation (“crude MDI”), and polyisocyanates containing carbodiimide groups, urethane groups, allophanate groups, isocyanurate groups, urea groups or biuret groups (“modified polyisocyanates”), in particular those modified polyisocyanates which are derived from 2,4- and/or 2,6-tolylene diisocyanate or from 4,4′- and/or 2,4′-diphenylmethane diisocyanate. Prepolymers of the above-mentioned isocyanates and organic compounds having at least one hydroxyl group may also be used. Examples of compounds having at least one hydroxyl groups which may be given are polyols or polyesters having one to four hydroxyl groups and (number average) molecular weights of 60 to 1,400. Most preferably used are the technically obtainable polyisocyanates by the name of “polymeric diphenylmethane diisocyanate”, having a functionality of higher than 2.0, as well as prepolymers produced from them.
In accordance with the present invention, polyol component B) comprises at least one polyether polyol (i.e. a poly(oxyalkylene) polyol) having a functionality of from about 2 to about 6 and a number average molecular weight of from about 1,000 to about 10,000 g/mole. Mixtures of such polyols may also be used as component B).
The poly(oxyalkylene) polyols sutiable for the present invention include those which can be prepared by, for example, the polyaddition of one or more alkylene oxides to one or more polyfunctional starter comp
Gossner Matthäus
Haas Peter
Herzog Klaus-Peter
Bayer Aktiengesellschaft
Brown N. Denise
Cooney Jr. John M.
Gil Joseph C.
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