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
1998-08-04
2001-11-27
Lipman, Bernard (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...
C524S773000, C524S775000, C524S789000, C526S298000
Reexamination Certificate
active
06323275
ABSTRACT:
The present invention relates to a cyanoacrylate adhesive composition having a weakened adhesion to the skin and can widely be used in various industries, medical fields, leisure fields, and household fields where cyanoacrylate adhesives are utilized as an instantaneous adhesive.
Cyanoacrylate adhesives containing 2-cyanoacrylate as a principal component have favorably been used in various industries, medical fields, leisure fields, and household fields as an instantaneous adhesive, since the adhesives have the property that 2-cyanoacrylate as a principal component is readily anionic-polymerized to rapidly cure in the presence of a very small amount of moisture or a basic substance.
However, 2-cyanoacrylate adhesives have such problems that the adhesives bond a part of the skin with another part of the skin of a person who handles the adhesive or that the adhesives bond the skin with other adherends than the skin if the adhesives were used incorrectly, while the adhesives have such a convenient property that they can join glass, metal, plastic, wood, fabric, and paper instantaneously.
The troubles are caused by the existence of moisture and basic substances contained in sweat and secretions on the surface of human skin. The moisture and basic substances accelerate anionic polymerization of 2-cyanoacrylate adhesives so that the skin is readily bonded.
Since the skin adheres to another part of the skin or other adherends through 2-cyanoacrylate adhesives with a high bonding strength, if the adhered skin was forced to be torn off, the skin or subcutaneous tissue may be seriously injured.
Based on the background mentioned above, the development of an instantaneous adhesive is strongly desired, which lowers such a trouble that the adhesive adheres to the skin at the time of adhesion operation and which can be handled more easily and safely than conventional instantaneous adhesives.
As a result of the study to solve the problems mentioned above, it has been found that a cyanoacrylate adhesive composition containing at least one specific aliphatic alcohol, aliphatic carboxylic acid ester, or carboxylic acid ester of a carbocyclic compound has a low bonding rate on the skin, but bonds adherends other than the skin such as woods, plastics, rubbers, metals, and ceramics instantaneously.
The present invention relates to a cyanoacrylate adhesive composition having a lowered adhesion to the skin, which comprises at least one compound selected from the groups mentioned below and an anionic polymerization accelerator:
A: An aliphatic alcohol in which the aliphatic group contains 6 or more carbon atoms directly bonded with each other;
B: An aliphatic carboxylic acid ester in which the aliphatic group contains 6 or more carbon atoms directly bonded with each other;
C: An aliphatic carboxylic acid ester having at least 2 aliphatic groups in which the aliphatic group contains 4 or more carbon atoms directly bonded with each other; and
D: A carboxylic acid ester of a carbocyclic compound having an aliphatic group as a carboxylic acid residue or an alcohol residue, in which said aliphatic group contains 5 or more carbon atoms directly bonded with each other.
The adhesive composition of the present invention will be described in detail below.
A principal component of cyanoacrylate adhesives is a 2-cyanoacrylate. Various kinds of 2-cyanoacrylates can be used as a principal component even in the adhesive composition of the present invention as in conventional cyanoacrylate adhesives, and specific examples of the 2-cyanoacrylates include methyl, ethyl, chloroethyl, n-propyl, i-propyl, allyl, propargyl, n-butyl, i-butyl, n-pentyl, n-hexyl, cyclohexyl, phenyl, tetrahydrofurfuryl, heptyl, 2-ethylhexyl, n-octyl, n-nonyl, oxononyl, n-decyl, n-dodecyl, 2-ethoxyethyl, 3-methoxybutyl, 2-ethoxy-2-ethoxyethyl, butoxy-ethoxy-ethyl, 2,2,2-trifluoroethyl, or hexafluoroisopropyl ester of 2-cyanoacrylic acid.
Specific examples of the aliphatic alcohol, under the Group A mentioned above, having an aliphatic group in which 6 or more carbon atoms are directly bonded with each other include monohydric alcohols, such as n-hexyl alcohol, n-octyl alcohol, n-nonyl alcohol, 2-nonyl alcohol, decyl alcohol (decanol), lauryl alcohol (dodecyl alcohol/dodecanol), tridecyl alcohol (tridecanol), tetradecyl alcohol, pentadecyl alcohol, &bgr;-citronellol, 9-decene-1-ol, 1,1-dimethyl-5-methyl-6-heptene-1-ol, dihydromyrcenol, geraniol, 1,5-dimethyl-1-vinyl-4-hexene-1-ol, and &ohgr;-undecenyl alcohol. While alcohols mentioned above are preferable in the present invention, the aliphathic alcohol is not restricted to such alcohols.
The alcohol used in the present invention is an aliphatic alcohol having an aliphatic group in which 6 or more carbon atoms are directly bonded with each other. If all of the aliphatic groups in the molecule have 5 or less carbon atoms directly bonded with each other, the bonding rate on the skin becomes fast and troubles are caused at the time of adhesion operation so that such alcohols can not be used to achieve the purpose of the present invention.
Conversely, when the alcohol has, in its molecule, an aliphatic group in which 16 or more carbon atoms are bonded, the solubility of the alcohol in a cyanoacrylate becomes worse. Accordingly, aliphatic alcohols used for the present invention preferably have an aliphatic group in which 15 or less carbon atoms are directly bonded with each other, and more desirably the alcohols have an aliphatic group in which 8 to 15 carbon atoms, particularly, 9 to 15 carbon atoms are directly bonded with each other.
As will be clear from the specific examples mentioned above, the aliphatic group is preferably a hydrocarbon group (linear or branched polymethylene or polyolefin).
When the amount of the aliphatic alcohol to be added to the adhesive composition of the present invention is small, a sufficient inadhesiveness to the skin can not be obtained. When the amount is too much, however, the bonding rate on adherends other than the skin becomes slow, and thus, it is desirable to adjust the concentration of the alcohol in the cyanoacrylate adhesive composition to 10 to 40% by weight, and more desirably to 15 to 30% by weight.
Specific examples of the aliphatic carboxylic acid ester, under the Group B mentioned above, having an aliphatic group in which 6 or more carbon atoms are directly bonded with each other, and examples of the aliphatic carboxylic acid ester, under the Group C mentioned above, having at least 2 aliphatic groups in which 4 or more carbon atoms are directly bonded with each other include the following compounds:
Monocarboxylic Acid Ester
Cetyl 2-ethyl hexylate, methyl ester of coconut fatty acid, methyl laurate, isopropyl myristate, methyl caprate, methyl oleate, isobutyl oleate, octyl oleate, 2-ethylhexyl crotonate, octyl acrylate, decyl methacrylate, tridecyl methacrylate, lauryl methacrylate, and lauryl propiolate.
Polycarboxylic Acid Ester
Bis(2-ethylhexyl)adipate, bis(2-ethylhexyl)maleate, dimethyl sebacate, bis(2-ethylhexyl)sebacate, bis(2-ethylhexyl)decamethylenedicarboxylate, 2,2,4-trimethyl-1,3-pentanediolmonoisobutylate, 2,2,4-trimethyl-1,3-pentanedioldiisobutylate, triglyceride 2-ethyl hexanoate, triglyceride caprylate, diglyceride caprylate, and triglyceride caprate.
Carboxylic Acid Ester Having at Least 2 Aliphatic Groups
Diisobutyl fumarate, diisobutyl maleate, tributyl acetyl citrate, and triglyceride caproate.
As explained above, the aliphatic carboxylic acid ester used in the present invention has an aliphatic group in which 6 or more carbon atoms are directly bonded with each other, or has at least 2 aliphatic groups in which 4 or more carbon atoms are directly bonded with each other. When all of the aliphatic groups in the molecule has 5 or less carbon atoms directly bonded with each other, or the aliphatic carboxylic acid ester does not have at least 2 aliphatic groups in which 4 or more carbon atoms are directly bonded each other, the bonding rate on the skin becomes high and troubles are apt to be caused at the time of adhesion.
However, w
Horie Takahashi
Kaai Asako
Okuyama Toshio
Tajima Seitaro
Takahashi Shin
Brobeck Phleger & Harrison LLP
Lipman Bernard
Toagosei Co. Ltd.
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