Stock material or miscellaneous articles – Composite – Of polyester
Patent
1997-05-09
1998-11-10
Acquah, Samuel A.
Stock material or miscellaneous articles
Composite
Of polyester
528272, 528274, 528283, 528296, 528297, 528302, 528306, 528308, 525437, 522 6, 428480, B32B 2706, C08G 6312
Patent
active
058341188
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to new hyperbranched polyesters and a process for the production thereof and curable resins comprising the polyesters.
Radiation-curable resins are increasingly used in various industrial applications, replacing conventional thermally cured and solvent based coatings and adhesives. The radiation-curable resins have favourable properties, e.g., high speed and low energy consumption of cure, solvent-free formulations, room temperature operation and high quality end-products. The principal components of a radiation-curable resin are oligomers (or prepolymers) and comonomers. The oligomers constitute the backbone of the three-dimensional polymer network formed by curing. Important types of oligomers commonly used for coating are acrylated epoxies, acrylated polyurethanes, unsaturated polyesters and acrylated polyesters (or polyethers) which give desired properties of the final cured films. However, those oligomers usually consist of linear molecular chains. The viscosity of the resin increases rapidly with increasing chain length of the oligomer. To obtain an operational viscosity of the formula for spraying, dipping, roll coating, etc., large amounts of multifunctional comonomer are required for the primary function of viscosity control. In addition, the comonomers have important effects on the cure reaction and the properties of the final product. Some of the comonomers have low cure rate, cause shrinkage of the film during curing, and have high costs and a limited shelf life. Multifunctional acrylates are the preferred monomers in radiation-curable systems because of their rapid curing rates and low prices. The common acrylate monomers are volatile and toxic, and have strong odour. Therefore, the trend is to use radiation-curable oligomers with viscosity close to the required application viscosity in order to reduce or eliminate the use of comonomers.
An object of the present invention therefore was to obtain oligomers with reduced viscosity compared to known oligomers with similar molecular weight.
A further object of the invention was to present oligomers which in resin applications needs a lower amount of multifunctional comonomers or none at all, while the resins still have a low viscosity, a high cure rate, an acceptable degree of curing and the final products have good mechanical properties.
A further object of the invention was to offer a process for the production of such oligomers.
The objects of the invention was solved by the hyperbranched polyester, the process for the production of these hyperbranched polyesters and resin comprising them, as claimed in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 depicts a reaction scheme for the synthesis of the hyperbranched polyester.
FIG.2 depicts an IR spectra of the products at different stages.
FIG. 3 depicts the molecular structure of the three polyester isomers.
FIG. 4 depicts an idealized formula of the hyperbranched methacrylated polyester with 8 double bonds.
FIG. 5 depicts an idealized formula of the hyperbranched methacrylated polyester with 16 double bonds.
FIG. 6 depicts molecular mass distribution of the hyperbranched methacrylated polyester D-1 analyzed with GPC analysis.
FIG. 7 depicts the dynamic, viscosity of the hyperbranched (meth)acrylated polyester.
FIG. 8 depicts flow time of hyperbranched polyesters and MUP using viscometric cup.
FIG. 9 depicts curing time and belt speed to tack-free state for UV cured polyester films.
FIG. 10 depicts glass transition temperatures of the cured hyperbranched polyesters.
Oligomers with a strongly branched structure are a new family of polymers which has been attracting increasing interest for many applications, e.g., in agriculture, medicine, cosmetics, adhesives and coatings. The oligomers are referred to as hyperbranched polyesters with a three-dimensional molecular architecture and possessing starburst topology (D. A. O'Sullivan, Chem. Eng. News, 20 (1993); D. A. Tomalia, A. M. Naylor, and W. A. Goddard III, Angew. Chem. Int. Ed. Engl., 29, 138 (1990). An impo
REFERENCES:
patent: 4557991 (1985-12-01), Takagiwa et al.
patent: 4558075 (1985-12-01), Suss et al.
patent: 5241019 (1993-08-01), Otsuki et al.
R.ang.nby Bengt
Wenfang Shi
Acquah Samuel A.
Neste Oy of Keilaniemi
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