摘要:
A novel method is disclosed for the preparation of a (meth)acryloxyalkyl group-containing organopolysiloxane having a linear structure by the ring-opening siloxane rearrangement polymerization reaction of a (meth)acryloxyalkyl group-containing cyclic organopolysiloxane oligomer either alone or in combination with a cyclic organopolysiloxane oligomer having no (meth)acryloxyalkyl groups. Different from conventional acidic catalyst, the reaction can be promoted by the use of a cation-exchange resin in the H.sup.+ form which can be readily removed from the polymerization mixture after completion of the polymerization reaction leaving no acidic matter which influences on the stability of the product. The catalytic efficiency of the cation-exchange resin can be further enhanced when the resin is, prior to contacting with the cyclic organopolysiloxane oligomer(s), impregnated or swollen with a polar organic solvent such as tetrahydrofuran.
摘要:
A radiation curable organopolysiloxane-containing composition is disclosed which is curable by the irradiation with actinic rays in a relatively low dose to give a cured layer having excellent surface-releasability so that the composition is useful, for example, as a coating agent of release paper for temporary protection of adhesive surface. The composition comprises (a) 0.1 to 20 parts by weight of a linear organopolysiloxane having at least one vinylphenyl or isopropenylphenyl group bonded to only one of the terminal silicon atoms in the molecular chain and (b) 99.9 to 80 parts by weight of a (meth)acrylate compound which is a (meth)acrylic acid ester of a polyhydric alcohol or a polyester of a polyhydric alcohol and a dibasic carboxylic acid esterified with (meth)acrylic acid at the residual hydroxy groups.
摘要:
A solventless curable silicone release composition contains (A) a branched organopolysiloxane having a vinyl group attached to a silicon atom at an end of its molecular chain, (B) an organohydrogenpolysiloxane having at least three SiH groups in a molecule, and (C) a platinum group metal catalyst. The composition is easily applicable to a thin gage and cures into a releasable silicone coating ensuring light release at high speeds. A release sheet having the cured coating formed thereon has improved release characteristics.
摘要:
Proposed is an improved radiation-curable organopolysiloxane composition capable of giving a cured surface film on a substrate surface which exhibits excellent releasability against sticky substances. The composition is obtained by combining two kinds of (meth)acryloxyalkyl-containing organopolysiloxanes in a specified weight proportion, of which one has a relatively large degree of polymerization but contains only a relatively small amount of the silicon-bonded (meth)acryloxyalkyl groups while the other has a relatively small degree of polymerization but contains a relatively large amount of the silicon-bonded (meth)acryloxyalkyl groups. By virtue of this unique formulation, the surface-release sheet provided with a cured surface film of this organopolysiloxane composition and attached to a sticky surface for temporary protection is safe from generation of a peeling noise which is unavoidable in the prior art when a surface-release sheet is peeled off from the sticky surface at a high peeling velocity, especially, when the peeling resistance is great.
摘要:
Disclosed is a method for imparting anti-sticking surface-releasability to the surface of a substrate which comprises: coating the surface with a novel radiation-curable (meth)acryloxy-containing organopolysiloxane; and curing the coating layer by the irradiation with radiation such as electron beams and ultraviolet light. Different from conventional radiation-curable (meth)acryloxy-containing organopolysiloxanes, the novel organopolysiloxane here used is characteristic in comprising at least one trifunctional organosiloxane unit in a molecule, by virtue of which the (meth)acryloxy-containing organopolysiloxane has good curability by the irradiation to exhibit excellent surface-releasability with high durability against aging.
摘要:
A novel organopolysiloxane compound is proposed which has, in a molecule, at least three (meth)acryloxy groups localized at only one of the molecular chain ends of the polysiloxane chain. By virtue of the localization of the (meth)acryloxy groups, the organopolysiloxane compound is highly curable by the irradiation with a radiation, e.g., electron beams and ultraviolet light, to give a cured coating film on a substrate surface exhibiting excellent releasability against sticky substances. A synthetic route for the preparation of such a one-end crosslinkable organopolysiloxane compound is described.
摘要:
Proposed is a radiation-curable organopolysiloxane composition which is useful as a coating agent for the formation of a releasable coating film on a substrate to serve as a releasable sheet without the problem due to generation of peeling noises. The composition essentially comprises, as a blend, (a) a first organopolysiloxane having a specified viscosity and containing (meth)acryloxyalkyl groups bonded to the silicon atoms in a specified content and (b) a second organopolysiloxane having a specified viscosity and containing (meth)acrylaminoalkyl groups bonded to the silicon atoms in a specified content, the weight proportion of the second organopolysiloxane to the first organopolysiloxane being in a specified range.
摘要:
A liquid silicone rubber coating composition exhibiting high adhesion for an airbag base fabric; a curtain airbag having a silicone rubber coating layer of the cured composition formed on at least one surface of the base fabric; and a method for producing such curtain airbag are provided. The composition comprises (A) an organopolysiloxane having at least 2 alkenyl groups bonded to the silicon atoms per molecule; (B) an organohydrogenpolysiloxane having at least 2 structural units represented by formula (1) per molecule, the structural units being linked by a non-siloxane structural unit not containing SiH group; (C) an addition catalyst; (E) an organosilicon compound having an epoxy group and an alkoxy group bonded to the silicon atom in the molecule; and (F) a titanium compound and/or a zirconium compound; and preferably (D) a fine powder silica having a specific surface area of at least 50 m2/g.
摘要:
A solvent-free silicone composition for release paper, comprising: (A) an organopolysiloxane represented by the following average compositional formula (1) (B) an organopolysiloxane represented by the following average compositional formula (2) (C) an organopolysiloxane having alkenyl groups only at its ends, represented by the following formula (3) and (D) an organohydrogenpolysiloxane represented by the following formula (4) , wherein the component (A) is contained in an amount of from 10 to 30 wt %, the component (B) is contained in an amount of from 10 to 30 wt %, the component (C) is contained in an amount of from 40 to 80 wt %, based on a total weight of the components (A), (B) and (C), and the component (D) is contained in such an amount that a molar ratio of the hydrogen atom or atoms bonded to a silicon atom to a total of the alkenyl groups of the components (A), (B) and (C) ranges from 1.0 to 4.0. The composition forms a tight release layer whose release force largely increases with release speed.
摘要:
A solvent-free silicone composition for release paper, comprising a mixture prepared by i) subjecting the organopolysiloxane (I) which is composed of R13SiO1/2 units, SiO4/2 units and (HO)SiO3/2 units, and has an OH group content of from 0.02 to 0.1 mol/100 g, to a partial condensation reaction in an organic solvent in the presence of an alkaline catalyst and the organopolysiloxane (II) represented by the following formula (2), and ii) removing the organic solvent, said mixture having an OH group content of less than 0.02 mol/100 g. The composition forms a tight-release layer stable with time.