Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
1998-06-15
2001-03-06
Szekely, Peter A. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C156S291000, C156S327000, C427S002310, C427S208200, C427S286000, C427S288000, C427S420000, C427S422000, C524S505000, C525S314000, C525S098000, C604S389000, C428S3550BL
Reexamination Certificate
active
06197845
ABSTRACT:
RELATED APPLICATION
This application claims priority to EP 97109865.2, filed Jun. 17, 1997.
FIELD OF THE INVENTION
The present invention relates to a hot melt adhesive composition useful for articles such as plasters, bandages and tapes which are adhesively adhered to skin. The adhesive may be coated continuously and preferably, discontinuously onto a substrate. More preferably, the hot melt adhesive composition is pattern-coated. The adhesive is permanently adhered to at least one substrate of the article and removably or releasably attachable to skin. The adhesive advantageously does not cause skin irritation nor transfers adhesive to the skin upon removal.
BACKGROUND OF THE INVENTION
Hot melt adhesives have been used to bond a variety of materials to many substrates. James P. Szymanski et al., U.S. Pat. No. 5,204,390, discloses pressure-sensitive hot melt adhesives comprising substantially saturated block copolymers, tackifying resin, and polybutene. This hot melt composition exhibits adhesive stability when exposed to ultra-violet light and is stable when contacted with plasticized surfaces.
Removable or releasable hot melt pressure-sensitive adhesives (PSA's) for articles such as feminine napkins, adult incontinent pads and the like are described as “garment attachment” or “positioning” adhesives. During manufacture of such articles, the hot melt PSA is typically slot-coated directly or transfer coated onto a polyolefin film substrate and then covered with a release liner. There are a multitude of patents pertaining to adhesive compositions for tapes, labels, adhesive bandages and the like. Collins et al., U.S. Pat. No. 4,136,699 specifically relates to hot melt PSA positioning adhesive compositions comprising substantially saturated block copolymers for feminine napkins.
In recent years, manufacturers have attempted to replace the continuous slot-coat method with various discontinuous methods, particularly by spray application methods, such as spiral spray and melt blown techniques or by pattern coating methods, otherwise referred to as screen-printing. There are several advantages in using a pattern coating technique, including aesthetic advantages due to the variety of screen designs as well as the ability to strategically place adhesive in precise locations. The primary advantage pattern coating offered is the ability to vastly reduce adhesive consumption, since the surface area per mass of adhesive is greatly increased.
However, hot melt PSAs employed for slot-coat applications tend to exhibit hot melt adhesive transfer to the surface it is removed from when coated discontinuously onto a substrate. Further, the hot melt adhesives known from the prior art have the drawback that they cause skin irritation when in contact with skin for a period of time. To counteract such skin irriation, the adhesive compositions of the prior art necessitate the addition of zinc oxide. Moreover, articles constructed from these hot melt adhesives often do not adhere properly to skin and thus can easily shift and become unattached. Finally, the hot melt adhesive compositions known from the prior art can separate from the substrate permanently adhered to due to mechanical influence.
Hence, industry would find advantage in a hot melt adhesive composition wherein the adhesive is permanently adhered to a substrate and is removably attachable to skin in order to secure an article for a period of time and can be subsequently removed without causing skin irritation or adhesive transfer.
SUMMARY OF THE INVENTION
The present invention is a hot melt adhesive composition comprising a block copolymer, a tackifying resin, an extending agent and optionally additives, wherein all the ingredients employed are substantially saturated. Preferably, the block copolymer has styrenic end block(s) and a midblock comprising ethylene/butylene, ethylene propylene, and mixtures thereof. Most preferred block copolymers have a solution viscosity of at least 50 cPs or greater, more preferably about 100 cPs, and most preferably about 200 cPs up to about 2000 for a 25 wt-% solution of the polymer in toluene at 25° C. and a diblock content of greater than about 35 wt-%, more preferably greater than about 50 wt-%, and most preferably ranging from about 70 wt-% to about 100 wt-% diblock.
The adhesive exhibits a combination of properties which are amenable to hot melt PSA pattern coating. The adhesive composition exhibits a ring and ball softening point of up to 125° C., a viscosity at 175° C. of from about 500 to about 20,000 mPa.s, a tensile strength of 0.10 to 0.80 N/mm
2
, an elongation at break from 500% to 1500%, and a needle pentration of 3 to 12 mm.
REFERENCES:
patent: 4032492 (1977-07-01), Englund et al.
patent: 4087824 (1978-05-01), Bronstert et al.
patent: 4136699 (1979-01-01), Collins et al.
patent: 4286077 (1981-08-01), St. Claire et al.
patent: 4314926 (1982-02-01), Allison, III
patent: 4460364 (1984-07-01), Chen et al.
patent: 4785996 (1988-11-01), Ziecker et al.
patent: 4833193 (1989-05-01), Sieverding
patent: 4857594 (1989-08-01), Lakshmanan et al.
patent: 5001179 (1991-03-01), Kauffman et al.
patent: 5057571 (1991-10-01), Malcolm et al.
patent: 5143776 (1992-09-01), Givens
patent: 5204390 (1993-04-01), Szymanski et al.
patent: 5217798 (1993-06-01), Brady et al.
patent: 5418052 (1995-05-01), Sugie et al.
patent: 5459193 (1995-10-01), Anderson et al.
patent: 5507901 (1996-04-01), Limina et al.
patent: 5559165 (1996-09-01), Paul
patent: 5569348 (1996-10-01), Hefele
patent: 5618883 (1997-04-01), Plamthottam et al.
patent: 5703162 (1997-12-01), Anderson
patent: 5719226 (1998-02-01), Kesley
patent: 5738689 (1998-04-01), Suzuki et al.
patent: 5741840 (1998-04-01), Lindquist et al.
patent: 5863977 (1999-01-01), Fisher et al.
patent: 0 616 018 (1994-09-01), None
patent: WO 94/02123 (1994-02-01), None
Endriss Gerhard
Janssen Annegret
H.B. Fuller Licensing & Financing Inc.
Quan Nancy N.
Szekely Peter A.
LandOfFree
Hot melt adhesive compositions for adherence to skin and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Hot melt adhesive compositions for adherence to skin and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Hot melt adhesive compositions for adherence to skin and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2548019