Stock material or miscellaneous articles – Layer or component removable to expose adhesive
Reexamination Certificate
1998-11-12
2001-05-22
Ahmad, Nasser (Department: 1772)
Stock material or miscellaneous articles
Layer or component removable to expose adhesive
C400S697100, C428S202000, C428S354000, C428S425100, C428S914000
Reexamination Certificate
active
06235364
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a pressure-sensitive correction tape comprising a tape-like foundation having a masking layer thereon. More particularly, it relates to a pressure-sensitive correction tape having performance wherein the masking layer thereof, once transferred on a receptor, can be readily removed with an eraser as required.
Heretofore, there has been known a method of using a multi-layer pressure-sensitive correction tape for masking erroneously typewritten letters or the like. A conventional pressure-sensitive correction tape of this type has a structure comprising a tape-like foundation having thereon a masking layer and a pressure-sensitive adhesive layer stacked in this order.
In conducting a masking operation using a pressure-sensitive correction tape, the masking layer is ocassionally erroneously transferred on a portion of a receptor which should not be masked. In this situation, it is necessary to remove the masking layer transferred on this portion. However, using the conventional pressure-sensitive correction tape, it is difficult to easily remove the transferred mashing layer from the receptor.
An object of the present invention is to provide a pressure-sensitive correction tape having high performance wherein the masking layer thereof, after being transferred onto a receptor, can be readily removed from the receptor.
The foregoing and other objects of the present invention will be apparent from the following detailed description.
SUMMARY OF THE INVENTION
In accordance with a first feature of the present invention, there is provided a pressure-sensitive correction tape comprising a foundation, a masking layer and a pressure-sensitive adhesive layer stacked on the foundation in this order, the masking layer comprising a masking agent, a polymer having rubber elasticity and an ester compound which is liquid at ordinary temperature and has a boiling point of not less than 130° C. at ordinary pressure.
In accordance with a second feature of the present invention, the pressure-sensitive correction tape with the first feature is further characterized in that the polymer having rubber elasticity comprises a styrene polymer and the ester compound being liquid at ordinary temperature comprises at least one member selected from the group consisting of di(2-ethylhexyl) adipate, di(2-ethylhexyl) sebacate, di(2-ethylhexyl) azelate, fatty acid triglyceride, trimethylolpropane trioctanoate, butyl benzyl phthalate, diisodecyl phthalate, trioctyl phosphate, tributyl phosphate, tri(butoxyethyl) phosphate, acetyl tributyl citrate and acetyl triethyl citrate.
In accordance with a third feature of the present invention, the pressure-sensitive correction tape with the first or second feature is further characterized in that a coating agent for the pressure-sensitive adhesive layer shows an adhesive strength of 10 to 70 g/25 mm according to the 180° peel method specified in JIS Z 0237.
The adhesive strength of the coating agent for the pressure-sensitive adhesive layer is a value determined according to the 180° peel method specified in JIS Z 0237-1991. A test specimen is prepared by the following method: A coating agent to be used for forming the pressure-sensitive adhesive layer is applied onto a 25 &mgr;m-thick polyethylene terephthalate film and dried to give a 1.2 &mgr;m-thick pressure-sensitive adhesive layer. A 25 mm-wide, 300 mm-long tape is cut off therefrom and used as a test specimen.
In the pressure-sensitive correction tape of the present invention, the masking layer comprises a masking agent, a polymer having rubber elasticity and an ester compound which is liquid at ordinary temperature and has a boiling point of not less than 130° C. at ordinary pressure.
By virtue of such a constitution of the masking layer, the polymer having rubber elasticity as a binder is modified by the plasticizing action of the ester compound being liquid at ordinary temperature and having a boiling point of not less than 130° C. at ordinary pressure, so that the polymer becomes soft and brittle and is endowed with tackiness. The masking layer thus lowered in its strength and endowed with tackiness is excellent in affinity with an eraser or the like, hence, is readily sticks thereto. As a result, the masking layer transferred onto a receptor can be readily broken by simple rubbing with an eraser or the like and readily removed.
In a preferred embodiment of the present invention, the polymer having rubber elasticity as a binder is a styrene polymer and the ester compound being liquid at ordinary temperature is at least one member selected from the group consisting of di(2-ethylhexyl) adipate, di(2-ethylhexyl) sebacate, di(2-ethylhexyl) azelate, fatty acid triglyceride, trimethylolpropane trioctanoate, butyl benzyl phthalate, diisodecyl phthalate, trioctyl phosphate, tributyl phosphate, tri(butoxyethyl) phosphate, acetyl tributyl citrate and acetyl triethyl citrate. In this embodiment, the binder is more effectively plasticized, thereby further facilitating the removal of the transferred masking layer.
In another preferred embodiment of the present invention, the adhesive strength according to the 180° peel method specified in JIS Z 0237 (hereinafter simply referred to as “adhesive strength”) of the coating agent for the pressure-sensitive adhesive layer is specified to a range of 10 to 70 g/25 mm. In this embodiment, the removal of the transferred masking layer is further facilitated without degrading the transferability of the masking layer.
The present invention will be more specifically explained.
Useful as the foundation are plastic films such as polyethylene terephthalate, polyethylene and polypropylene, and paper sheets such as glassine paper. The plastic films preferably have a thickness of about 10 &mgr;m to about 50 &mgr;m and the paper sheets preferably have a basis weight of about 30 to about 50 g/m
2
. As required, a releasing agent is applied on one or both sides of the foundation to reduce the adhesion of the adhesive layer to the back side of the foundation during the storage of the pressure-sensitive correction tape wound in the form of a roll or to facilitate the release of the masking layer from the foundation in transferring. Examples of the releasing agents include silicone resins and fluorine-containing resins. Also usable as the foundation are commercially available foundations previously coated with a releasing agent.
The masking layer in the present invention is composed of a masking agent, a polymer having rubber elasticity and an ester compound which is liquid at ordinary temperature and has a boiling point of not less than 130° C. at ordinary pressure.
Examples of specific polymers having rubber elasticity are styrene polymers, polyurethane rubbers, fluorine-containing rubbers, acrylonitrile-butadiene rubbers, ethylene-vinyl acetate copolymers, ethylene-alkyl acrylate copolymers, chlorosulfonated polyethylene and cyclized rubbers. These polymers may be used either alone or in combination of two or more species thereof in consideration of the transferability or the like of the masking layer.
The preferred polymers having rubber elasticity are styrene polymers for the ease of use with the ester compound which is liquid at ordinary temperature and has a boiling point of not less than 130° C. at ordinary pressure. Examples of the styrene polymers are styrene-butadiene-styrene block copolymer (SBS), styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-butadiene rubber, styrene-isoprene-styrene block copolymer (SIS), and styrene-ethylene/propylene block copolymer (SEP). These may be used either alone or in combination of two or more species thereof.
A resin may be used in combination with the polymer having rubber elasticity as a binder for the masking layer. By the combined use of the resin with the polymer, it is possible to improve the cut-off performance of the masking layer and to adjust the hardness of the masking layer. Examples of specific resins include hydrocarbon resins, styrene-acryl copolymer, ketone resins,
Imanishi Masayuki
Katsuro Noboru
Miyai Kazuo
Ahmad Nasser
Fish & Neave
Fujicopian Co. Ltd.
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