Polysiloxane-grafted copolymer pressure sensitive adhesive composition and sheet materials coated therewith
AssigneeMinnesota Mining and Manufacturing Company
InventorMieczyslaw H. Mazurek
Life of this patent
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Abstract
This invention provides pressure sensitive adhesive (PSA) compositions comprising a copolymer having a vinyl polymeric backbone having grafted thereto polysiloxane moieties. The compositions may contain other ingredients such as tackifier and/or plasticizer. An exposed surface of the PSA composition is initially positionable on a substrate to which it will be adhered but, once adhered, builds adhesion to form a strong bond. The PSA compositions may be used alone or in blends with unsiliconized PSA compositions. The invention also provides sheet materials coated with the PSA composition such as tape, labels, etc.
Claims21
A pressure sensitive adhesive composition comprising:
- (a) a copolymer which has a vinyl polymeric backbone having grafted to it monovalent siloxane polymeric moieties, said copolymer comprising A, C, and, optionally, B monomers wherein:
- A is at least one free radically polymerizable vinyl monomer;
- B, when used, is at least one reinforcing monomer copolymerizable with A, the amount by weight of B monomer being up to about 20% of the total weight of all monomers in said copolymer, said B monomer being selected from the group consisting of polar monomers and macromers having a T.sub.g or a T.sub.m above about 20.degree. C.;
- and
- C is a polymeric monomer having the general formula
- X(Y).sub.n Si(R).sub.3-m Z.sub.m
- wherein:
- The amount and composition of C monomer in the copolymer is such as to provide said pressure sensitive adhesive composition with a decrease in initial peel adhesion value relative to that of an adhesive composition comprising a polymer of A and B, if used, without C and in the same relative amounts of A and B, if used, and of substantially the same molecular weight;
- X is a vinyl group copolymerizable with the A and B monomers;
- Y is a divalent linking group;
- R is a hydrogen, lower alkyl, aryl, or alkoxy;
- Z is a monovalent siloxane polymeric moiety having a number average molecular weight of at least about 500 and is essentially unreactive under copolymerization conditions and is pendant from said vinyl polymeric backbone;
- n is zero or one;
- m is an integer of from one to three
- (b) up to about 150 parts by weight compatible tackifying resin per 100 parts copolymer;
- and
- (c) up to about 50 parts by weight of compatible plasticizer per 100 parts copolymer,
- said adhesive composition having a peel adhesion value which is lower initially when an exposed surface of said adhesive composition is first applied to a substrate but which builds with time once applied to approach the peel adhesion value of the adhesive composition without C.
The tape of 18 in roll form.
Dependencies are inferred from the claim text.