Silicone pressure-sensitive adhesives with control removal property
First Claim
1. A pressure sensitive adhesive, having improved control removal properties, said adhesive comprising a resin/organopolysiloxane composition curable to produce a pressure sensitive adhesive said organopolysiloxane composition curable to produce a pressure sensitive adhesive comprising about 50 to about 75 parts by weight of a benzene toluene-soluble siloxane resin, about 25 to about 50 parts by weight of vinyl-and hydride-containing organopolysiloxanes, a Pt catalyst, and from 0 to about 40 weight percent organic solvent and from about 0.5 to about 15 weight percent based upon the resin/organopolysiloxane composition of a chemically compatible high molecular weight organopolysiloxane having the general formula:
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space="preserve" listing-type="equation">RR.sup.1.sub.x SiO(R.sup.1.sub.2 SiO).sub.x (RR.sup.2 SiO).sub.y SiR.sup.1.sub.2 R (1)wherein each R1 is independently an alkyl or aryl group having from 1 to about 10 carbon atoms, each R2 is independently an alkyl or aryl group having from 1 to about 10 carbon atoms, each R is independently chosen from R1 or R2, x is an integer, and y is an integer, x and y having values such that the chain-length dependent viscosity of the chemically compatible high molecular weight polyorganosiloxane is at least 1500 cps at 25°
C.
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Accused Products
Abstract
Distortion and haze of pressure sensitive tapes upon removal can be minimized by incorporating a small amount of chemically compatible, high molecular weight silicone polymer release modifier to the curable PSA compositions. Organopolysiloxanes of the general formula:
RR.sup.1.sub.2 SiO(R.sup.1.sub.2 SiO).sub.x (RR.sup.2 SiO).sub.y
SiR12 R
are used as the release modifier, wherein each R1 and R2 is independently an aryl or alkyl group having from 1 to about 10 carbon atoms, each R is independently chosen from the following groups: R1, R2, alkenyl having from 1 to about 10 carbon atoms, hydrogen, alkoxy (such as methoxy, ethoxy, propoxy, etc.) hydroxy, epoxy, amino, and fluoroalkyl having up to 10 carbon atoms; x and y are each an integer such that the value of (x+y) is sufficient to yield a composition having a viscosity of from at least 1500 cps at room temperature to as high as the viscosity of silicone gums. When compared to similar compositions without the release modifier, a cured silicone PSA with much less distortion, a smoother surface, and clearer optics is obtained upon removal or dispensing.
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Citations
9 Claims
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1. A pressure sensitive adhesive, having improved control removal properties, said adhesive comprising a resin/organopolysiloxane composition curable to produce a pressure sensitive adhesive said organopolysiloxane composition curable to produce a pressure sensitive adhesive comprising about 50 to about 75 parts by weight of a benzene toluene-soluble siloxane resin, about 25 to about 50 parts by weight of vinyl-and hydride-containing organopolysiloxanes, a Pt catalyst, and from 0 to about 40 weight percent organic solvent and from about 0.5 to about 15 weight percent based upon the resin/organopolysiloxane composition of a chemically compatible high molecular weight organopolysiloxane having the general formula:
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space="preserve" listing-type="equation">RR.sup.1.sub.x SiO(R.sup.1.sub.2 SiO).sub.x (RR.sup.2 SiO).sub.y SiR.sup.1.sub.2 R (1)wherein each R1 is independently an alkyl or aryl group having from 1 to about 10 carbon atoms, each R2 is independently an alkyl or aryl group having from 1 to about 10 carbon atoms, each R is independently chosen from R1 or R2, x is an integer, and y is an integer, x and y having values such that the chain-length dependent viscosity of the chemically compatible high molecular weight polyorganosiloxane is at least 1500 cps at 25°
C. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification