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
2001-02-05
2003-11-18
Mulcahy, Peter D. (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...
C524S098000, C524S315000, C524S354000, C524S357000, C524S481000, C524S483000, C524S484000
Reexamination Certificate
active
06649681
ABSTRACT:
FIELD OF INVENTION
The present invention concerns an adhesive composition primarily intended for use in medical applications, and more particularly an adhesive composition primarily intended for use in bonding polymeric fittings to olefin-containing components of articles used in medical applications.
BACKGROUND OF THE INVENTION
For many years, polyvinyl chloride (PVC) has been the most prevalently used polymer in medical applications such as, for example, IV and blood bags, surgical tubing and related components, catheters, and inhalation masks. Alone, PVC is a hard and rigid substance. However, when PVC is plasticized with any one of several U.S. Food and Drug Administration (FDA) sanctioned plasticizers such as, for example, di-ethylhexyl phthalate (DEHP), tri (2-ethylhexyl) trimellitate (TOTM), and citrate esters, PVC becomes flexible yet strong, kink resistant, and can be easily solvent welded to other polymeric components using solvents such as cyclohexanone.
Although PVC has been widely used in medical applications successfully for many years, medical device manufacturers have recently been developing products that are fabricated from materials other than PVC. Several companies such as Ferro Corporation, the assignee of the present invention, are now marketing strong, flexible, transparent, FDA sanctioned olefin-containing compositions (which are also sometimes referred to as polyolefin alloys) as an alternative to PVC for use in medical applications. These proprietary olefin-containing compositions generally offer improved strength and flexibility characteristics when compared with PVC, but more importantly also provide a non-plasticized DEHP-free product.
While olefin-containing compositions offer some advantages over PVC and other polymers used in medical applications, the use of such olefin-containing materials has been hindered to some degree by the difficulties presented in bonding such materials to fittings made from polymeric materials such as polyester, high density polyethylene, acrylonitrile butadiene styrene, polyolefins, polycarbonate, and acrylic. Due to their low solubility in many solvents and their low surface energy, it is difficult, generally speaking, to obtain good adhesion of polymeric fittings to olefin-containing components using conventional adhesives.
For these and other reasons, an adhesive composition is needed that can be used to bond a polymeric fitting to an olefin-containing component of an article used in medical applications. Such an adhesive composition must contain only FDA sanctioned materials (e.g., materials that meet the requirements for USP Class VI) and must provide excellent adhesion between olefin-containing components and fittings formed from a variety of polymers.
SUMMARY OF INVENTION
The present invention provides an adhesive composition for use in bonding a polymeric fitting to an olefin-containing component of an article used in medical applications. The adhesive composition according to the invention comprises an adhesive polymer system dissolved in a solvent system. The solvent system comprises an organic solvent having a solubility parameter within the range of from about 7.5 to about 10 (cal/cm
3
)
1/2
. Subsequent to forming a bond between the polymeric fitting and the olefin-containing component, the adhesive composition can meet the requirements for USP Class VI materials. In a preferred embodiment of the invention, the adhesive composition comprises a low shear mixture of an adhesive polymer system comprising an atactic polypropylene and a low density polyethylene that is dissolved in a solvent system comprising a blend of d-limonene and a ketone selected from the group consisting of 4-heptanone and cyclohexanone.
The adhesive composition can be used, for example, to bond polymeric fittings made of materials such as, but not limited to, acrylic, polycarbonate, polyvinyl chloride polyolefin, acrylonitrile butadiene-styrene, and polyester, to olefin-containing components of articles used in medical applications such as, but not limited to, tubing. The present invention also provides a method of making the adhesive composition and a method of bonding a polymeric fitting to an olefin-containing component of an article used for medical applications using the adhesive composition.
DETAILED DESCRIPTION
The present invention provides an adhesive composition for use in bonding a polymeric fitting to an olefin-containing component of an article used in medical applications. Unless the context clearly indicates otherwise, as used in the instant specification and in the appended claims, the term “olefin-containing” means that the material contains one or more thermoplastic polymers derived from olefin monomers. Olefin-containing materials can be homopolymers of olefin monomers, copolymers derived in part from olefin monomers, and polyblends that contain such olefinic homopolymers and/or copolymers blended with other polymers. Olefin-containing materials of this type are sometimes referred to herein as olefin alloys. As noted above, this application claims benefit of U.S. Provisional Application Ser. No. 60/179,978, filed Feb. 3, 2000, which is hereby incorporated by reference in its entirety.
Most of the commercial producers of olefin alloys used in medical applications regard the exact formulation of their materials as proprietary information. In general, these commercially available olefin alloys contain a major part of an olefinic homopolymer or copolymer and minor amounts of other polymers and other additive materials. For example, Ferro Corporation, the assignee of the present invention, markets a line of proprietary polyolefin alloys under the trade designation RxLoy™, such as Ferro Product Code No. NPP00NR02NA (hereinafter “Ferro NR02”), which includes a major amount of low density polypropylene, a lesser amount of metallocene copolymer of ethylene octene and hexene, and a minor amount of ethylene vinyl acetate and other functional additives.
The adhesive composition according to the present invention is particularly useful for bonding polymeric fittings to olefin-containing components used in medical applications such as NR02 tubing. Polymeric fittings used in medical applications are typically formed from materials such as, for example, polycarbonate resin, high density polyethylene, acrylic resin, acrylonitrile-butadiene-styrene resin, polyester resin, olefin-containing alloys, and block copolymers of polystyrene and polyisoprene.
The adhesive composition according to the present invention comprises an adhesive polymer system dissolved in a solvent system. Subsequent to forming a bond between the polymeric fitting and the olefin-containing component, the adhesive composition according to the invention is capable of meeting the requirements for USP Class VI materials. As used in the instant specification and in the appended claims, phrases such as “meets the requirements for USP Class VI materials” or the like mean that a material meets or exceeds the “Biological Reactivity Tests, in Vivo” for Class VI materials set forth in USP XXIII. These tests are described in detail at col. 4, line 35 through col. 11, line 26 of Lee et al., U.S. Pat. No. 5,925,246, and that portion of Lee et al. is hereby incorporated by reference.
Each of the components of the adhesive composition, as well as the most preferred embodiment of the invention, is separately discussed in greater detail below.
Solvent System
The adhesive composition according to the present invention comprises a solvent system. Preferably, the solvent system comprises from about 65% to about 97% of the adhesive composition by weight. The solvent system preferably comprises a blend of at least two compatible organic solvents. Compatible organic solvents are solvents that are miscible and do not undergo phase separation upon standing.
The solvents in the solvent system preferably have a solubility parameter within the range of from about 7.5 to about 10 (cal/cm
3
)
1/2
, more preferably from about 7.9 to about 9.0 (cal/cm
3
)
1/2
, and most preferably from about 8.1 t
Birch Timothy W.
Chundury Deenadayalu
Kempthorn James T.
Rohn Andrew M.
Scheibelhoffer Anthony S.
Ferro Corporation
Mulcahy Peter D.
Rankin, Hill Porter & Clark LLP
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