Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Patent
1995-02-06
1996-04-30
Michl, Paul R.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
524481, 524515, 525240, C08K 501, C08L 9108, C08L 2300
Patent
active
055126251
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to a thermoplastic hotmelt adhesive based on a polymer blend of polyolefins and to its use.
BACKGROUND OF THE INVENTION
Hotmelt adhesives are adhesives which are solid at room temperature and which are applied to the substrates to be joined in the form of a melt, solidifying on cooling after the substrates have been joined together. In the case of thermoplastic adhesives, this operation can be repeated indefinitely because they do not cross-link. They are essentially based on polymers, such as polyamides, polyesters or polyolefins. These polymers critically determine the properties of the adhesive layer in regard to adhesion, strength and temperature behavior. In order to obtain special properties for specific applications, additives are incorporated, for example tackifiers to increase adhesion, plasticizers to increase flexibility, waxes to shorten the open time or crystallization accelerators to improve morphology. However, the properties of the hotmelt adhesives can also be modified as required by mixing basic polymers of the same type or of different types. It is known that polymer blends such as these can increase impact strength and notched impact strength, for example, under certain conditions. Their morphology is crucial in this regard. This morphology is generally composed of a crystalline hard-elastic matrix phase and a disperse soft-elastic phase. On exposure to loads at high deformation rates, the stresses occurring are largely absorbed by the soft-elastic phase.
RELATED ART
It is generally known that polyolefins of the following types can be used as raw materials for hotmelt adhesives: ethylene/vinyl acetate copolymers, ethylene/ethyl acrylate copolymers or polyisobutene. "Polyolefins" in this context are understood to be polymers with the following general structure: branched, saturated, aliphatic or cycloaliphatic or aromatic group. The polyolefins also include copolymers thereof with olefins containing hetero atoms, such as acrylic acid, maleic acid or vinyl esters, including their derivatives. Where R.sub.1 is hydrogen, the polyolefins are known as poly-.alpha.-olefins.
Polyolefins such as these are described, for example, by Schleinzer (cf. Materiaux et Techniques (1990), pages 47-52). Interest centers on terpolymers of ethylene, propylene and but-1-ene. They may be used for lamination, for assembly, in the hygiene field and for packaging and labeling. Various polymer blends are proposed for the particular applications. Thus, up to 30% by weight of tackifiers are said to be added to improve tackiness (see page 49, left-hand column, upper half and page 50, left-hand column, paragraph 4). To increase the softening temperature, melt viscosity and heat resistance, isotactic polypropylene above all is said to be added (see page 49, middle). To make the mixture of the terpolymer and wax less brittle and more compatible, polyisobutylene is said to be added (page 49, left-hand column, middle). Hotmelt adhesives of the terpolymer, a tackifier, a polyethylene wax or a polypropylene wax and, optionally, an additional polyisobutylene are described for packaging purposes (see page 51, right-hand column and page 52). To improve adhesion to polar substrates, such as metal and glass, the amorphous poly-.alpha.-olefin may be modified by functional groups (see page 48, right-hand column, second paragraph).
BRIEF DESCRIPTION OF THE INVENTION
Against the background of this prior art, the problem addressed by the present invention was to improve both the production properties and the processing properties of hotmelt adhesives and also their performance properties. In particular, the invention set out to improve toughness, heat resistance, viscosity behavior and low-temperature properties in the range from -30.degree. to +130.degree. C. and preferably above 20.degree. C.
The solution to this problem as provided by the invention is defined in the claims. It is essentially based on the use of an oligomer of .alpha.-olefins containing at least 4 carbon atoms
REFERENCES:
patent: 4022728 (1977-05-01), Trotter et al.
patent: 4120916 (1978-10-01), Meyer, Jr. et al.
patent: 4186258 (1980-01-01), Schmidt et al.
patent: 4761450 (1988-08-01), Lakshmanan et al.
Andres Johannes
Butterbach Ruediger
Kopannia Siegfried
DeWitt LaVonda R.
Henkel Kommanditgesellschaft auf Aktien
Jaeschke Wayne C.
Michl Paul R.
Ortiz Daniel S.
LandOfFree
Thermoplastic hotmelt adhesive does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Thermoplastic hotmelt adhesive, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Thermoplastic hotmelt adhesive will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-629404