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...
Reexamination Certificate
2002-03-12
2004-01-27
Wu, David W. (Department: 1713)
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...
C524S538000, C525S178000, C525S245000, C525S420000
Reexamination Certificate
active
06683128
ABSTRACT:
The present invention relates to fluorinated compounds usable as additives for hydrogenated resins, for example polyolefins, elastomers and polymers from, polycondensation. The additives of the invention do not negatively affect the processability during the extrusion of hydrogenated resins, on the contrary they improve it and the finished manifactured article shows an improved mould release. Besides, the finished manufactured article (hydrogenated resin added with the invention additives) shows lasting improved surface properties.
More particularly the present invention relates to additives formed by perfluoropolyether chains and functionalized polyolefins. Said additives can be obtained in solid form (granules, powder or pellets) and are compatible with hydrogenated polymers with which they form homogeneous mixtures. Therefore masterbatches at various additive concentrations, even very high, can be prepared, with hydrogenated resins, even of the order of 50% by weight of additive.
In the prior art the use of fluorinated additives to improve the polymer properties is known. U.S. Pat. No. 4,278,776 describes the use of polyamides obtained from perfluoropolyethers as process additives for blends of curable fluorinated rubbers. Tests carried out by the Applicant showed that polyamides obtained from perfluoropolyethers do not allow to prepare masterbatches with hydrogenated resins at high concentration of this additive. Besides even at low concentrations of this additive a homogeneous masterbatch is not obtained. Therefore these masterbatches are not in practice usable in extrusion since finished manufactured articles are obtained having non uniform properties. (See the comparative Examples). U.S. Pat. No. 5,061,759 describes perfluorinated perfluoropolyether additives or having bromine end groups for fluorinated rubbers curable by peroxidic way, the additive amount being in the range 0.5-1% by weight. These additives improve the processability of the fluorinated rubbers and the mould release. Also these additives when used for hydrogenated resins to obtain masterbatches to be used for preparing manufactured articles give the same drawbacks of the polyamides obtained from perfluoropolyethers.
U.S. Pat. No. 3,899,563 describes. monofunctionalized fluoro alkyl additives, such as amides, diamides, triazines, substituted ureas, for thermoplastic resins. In said patent no mention is made to the possibility to prepare masterbatches of above additives with hydrogenated resins, in particular no mention is made to polyolefins.
U.S. Pat. Nos. 5,143,963 and 5,286,773 describe fluorinated additives for hydrogenated thermoplastic polymers. Among the various additives, perfluoropolyether additives are mentioned and only perfluoropolyethers having perfluorinated end groups are exemplified. The additive amount is in the range 0.01%-<1% by weight. The finished manufactured articles have a surface tension lower than that of the thermoplastic polymer and show a higher fluorine content on the surface than inside the compound. The manufactured article is characterized by a higher hydrophobicity and antiadherence, a lower friction and a smoother surface. The fluorinated compounds used as additives can be under the form of oil, grease, or rubber. With these additives it is not possible to prepare masterbatches having a high content of additives, for example of 20% (see the comparative Examples). Besides, to additivate the liquid fluorinated compounds, particular equipments must be used so as to have a high mixing efficiency and therefore twin-screw extruders are used. Tests carried out by the Applicant have shown that by using the standard single screw extruders, widely used industrially, it is not possible to prepare masterbatches even at concentrations lower than 1% by weight.
U.S. Pat. No. 5,025,052 describes fluorinated dioxazolidinones as additives for thermoplastic resins. Also in this case no mention is made to the preparation of masterbatches with high additive concentrations.
U.S. Pat. Nos. 5,681,963 and 5,789,491 describe the use of imides based on monofunctional perfluoroalkyl compounds as additives in the production of fibers (polyolefins, polyesters, polyamides) water-repellent, alcohols and fluids having a low surface tension. In said patents it is stated that fluorinated polymer derivatives are not suitable for this kind of use due to their insufficient capability to migrate on the surface. Patent applications WO 97/22,576 and WO 97/22,659 describe the use of mono- and diesters of fat acids, excluding the stearic acid, with monofunctional fluoroalkyl alcohols to give idro/oilrepellent properties to polymer fibres, in particular polypropylene fibres. Also in this case the polymer additives are considered unsuitable as above mentioned.
Patent application WO 99/23,149 describes the preparation of manufactured articles resistant to creaking by addition of a generic fluorinated additive under the form of oil, wax or rubber, in amounts in the range 0.01%-5% by weight, to a hydrogenated polymer such as polyurethane or both thermoplastic and thermosetting resins. Also perfluoropolyethers even having functional end groups, and their homologues having a higher molecular weight, with a fluorine content higher than 50% belong to the class of fluorinated additives. In said patent application it is indicated that when the polymer is thermoplastic, to prepare these compositions the polymer is melted and mixed in the liquid state with the fluorocarbon additive, and the additive feeding into the mixing equipment takes place by addition devices for liquids. Therefore this mixing process shows the drawback to require a particular equipment since the components, as said, must be added at the liquid state. Also perfluoropolyethers having perfluoroalkyl end groups are indicated as usable. Also for said patent application the above same considerations are valid.
Patent application WO 99/23.148 describes manufactured articles resistant to abrasion obtained by addition of 0.01% up to 1% of one of the fluorinated additives described in the previous patent application for thermosetting resins. No reference is made to masterbatches.
Patent application WO 99/23,147 describes linear or crosslinked polymers having a Shore A hardness from 10 to 90, modified by addition of fluorinated additives in amounts between 1 and 10%, to obtain an improved abrasion resistance. In above patent application fluorinated additives oils, rubbers or greases formed by fluorocarbons which can contain functional groups are indicated as suitable. The mixing equipment is the one used to mix liquid compounds described in patent application WO 99/23,149 and therefore also this mixing process shows the same above mentioned drawback.
U.S. Pat. No. 5,451,622 describes the use of partially fluorinated piperazines with monofunctional fluoroalkyl segments, containing a fluorine amount between 20 and 70% by weight as hydro/oilrepellent additives for hydrogenated resins, such as for example polypropylene. Also in said patent no mention is made to masterbatches having a high concentration of additive.
Generally according to the above prior art the fluorinated additives can be used as process additives, or as additives to give improved surface properties to the finished manufactured article. The addition procedure of the fluorinated additive into the hydrogenated resin is generally a complicated step and requires, as seen, particular equipments for the dosage of the fluorinated additive in extrusion. The additive indeed is often under the liquid form and high efficiency equipments as twin-screw extruders for the homogeneization with the resin are required. With the liquid fluorinated additives of the prior art it is difficult to prepare masterbatches having a high additive concentration in the hydrogenated resin, in particular at concentrations higher than 10% by weight of additive. When perfluoropolyethers are used as additives, masterbatches having a maximum concentration of additive of 1-2% by weight can be prepared. (See comparative Examples). Th
Sanguineti Aldo
Scicchitano Massimo
Turri Stefano
Arent Fox Kintner Plotkin & Kahn
Ausimont S.p.A.
Hu Henry S
Wu David W.
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