MXPA96005612A - Silicone compositions curable by radiation and / or hume - Google Patents

Abstract

The present invention relates to: A silicone composition curable by radiation and / or humidity, comprising: a silanol-containing silicone, a silane crosslinker for silicone, said crosslinker having directly linked to silicon lattice thereof, an ethylenically unsaturated functional group and at least two hydrolysable functional groups, and an effective photoinitiator for the radiation cure of the silicone composition. Also described is a "liquid packaging system" formulation, which is subsequently irradiated to be delivered to the packaging site (64), so that a cover layer of the cured surface resulting from the radiation (102) is superposed and contains (cooperatively with the associated binding surface (s) of the packaging site) the uncured liquid (100), while a packaged structural element (66) is encapsulated in the uncured liquid medium (buffered

Description

SILICONE COMPOSITIONS CURABLE BY RADIATION AND / OR MOISTURE FIELD OF THE INVENTION The present invention relates to silicone compositions curable by radiation and / or moisture, and to a method of making and using the same. Description of the Related Art Silicone materials are widely used in the industry as well as in consumer markets such as sealants, adhesives, coatings, packaging compounds, etc. These materials include the so-called vulcanizable silicones at room temperature (RTV) that are curable under ambient conditions (room temperature), in the presence of atmospheric humidity. Typically, silicone materials vulcanizable at room temperature are manufactured by terminating the end of silicones terminated by α, β-silanol with various crosslinkers such as alkoxysilanes, oximinosilanes, acetoxysilanes, aminosilanes, and other silanes with hydrolyzable groups attached to the silicon atom or atoms of the same. The vulcanizable silicone materials at room temperature are stored in moisture-proof containers. During the application the materials are extruded or applied in another way and exposed to environmental conditions for their cure. The moisture in the air will then hydrolyze the hydrolysable groups (alkoxy, oximino, acetoxy, amino, etc.) in the silicon atom (s) to form silanol, either with or without the aid of an added catalyst. The resulting silanol can then further react with the remaining non-hydrolyzed groups in a condensation reaction, to form a. Siloxane bond resulting in the cure of the silicone material. The reactions mentioned above are illustrated below: -Yi-0H + RnSiX4.n? Si-0SiR "X3.n + HX (1) where R = alkyl, aryl and so on, X = 0R, oximino, acetoxy, amino, amido and so on, and n = 0-2. Depending on the group X, the above reaction may or may not require the aid of a catalyst.

Yes-0SÍRnX3. "+ H20? Si-OSiRnX2.il (OH) + HX (2) Again, depending on the group X, there may or may not be catalyst or catalysts.

-YES-OSÍRnX2.n (OH) + -Si-OSiR, ^ ,, -Si-OSiRnX2n-0-SiRnX2-? P-Si + HX (3! Although materials vulcanized at room temperature are very reliable and possess superior properties in the aforementioned end-use applications (sealants, adhesives, coatings, packaging compounds, etc.), frequently vulcanizable materials at room temperature cure very slowly. For example, a typical silicone formulation often needs to be cured overnight before fully acceptable healing properties can be realized for the intended end-use applications. As a result, there is a "need to" fix, ie, spatially immobilize, vulcanizable material at room temperature applied rapidly, so that the applied material does not move from the intended site of use, before a complete cure is achieved. of the vulcanizable silicone at room temperature This migration can be extremely detrimental.For example, if a vulcanizable sealant formulation is applied at room temperature to a joint to effect the waterproof sealing thereof, migration may occur as a fall or Seal of the seal (in the absence of adequate cure of the formulation.) The migrated sealing formulation as a result may no longer be on the joint to be sealed, so that the joint structure considered may be deficient or even useless for its intended purpose, considering other applications of silicone materials, silicone shaped coatings They are widely used in the protection of delicate electronic components such as printed circuit boards as well as abrasion resistant coatings for plastic lenses. Typically, the shaped coatings are heat cured using hydrosilylation reactions, or also cured with moisture using vulcanization at conventional room temperature. In the formulation and use of heat-cured shaped silicone coatings, the silicone fluids with vinyl functional groups are reacted with silicone fluids containing silicon-hydrogen bonds in the presence of a transition metal catalyst, such as for example chloroplatinic acid. The severity of the required healing conditions, together with the high cost of transition metal catalysts, has placed a serious obstacle to the use of these heat-cured silicone coatings. The deficiencies of conformal silicone coatings cured with moisture with respect to their slow cure speed have already been noted above. This slow speed places a severe limitation on the manufacture of coated components, since complete curing of the coated components is needed before the components can be used in the next step of the manufacturing process. Due to the aforementioned limitations involved with silicone formulations heat or moisture curable, a third mode of curing, UV curing (uv) has recently gained wide acceptance. The curing of radiation curable silicones by ultraviolet light or other actinic radiation is relatively fast and harmless to substrates. In situations where the portions of the coating material become overshadowed during curing by ultraviolet light, a secondary cure mode may also be incorporated, usually moisture cure. Typically, healing by ultraviolet light can be achieved either by a thiolene cure or by acrylate cure. In the thiolene cure, a functional thiol silicone is reacted with a functional vinyl silicone. The healing is quick and the surface dries to the touch after finishing the healing. However, the finished coating poorly resists heat aging and the formulation tends to be unstable in storage. On the other hand, functional acrylate silicone is usually storage stable and cured coatings exhibit excellent high temperature resistance. However, acrylate cure typically exhibits oxygen inhibition. That is, in the presence of atmospheric oxygen, the surface cure tends to be incomplete and the resulting cured coatings tend to be viscous. The art has proposed a wide variety of silicone compositions, but these compositions have failed to satisfactorily overcome the aforementioned deficiencies of conventional room temperature vulcanizable silicones, heat cured silicones, and radiation curable silicones. U.S. Patent No. 4,526,955 to Bennington et al. Discloses radiation polymerizable compositions that include organopolysiloxanes having -N-Si or N-O-Si bonds. Japanese Patent Application No. 4-69901 filed on February 12, 1992 by Three-Bond Co., Ltd. discloses a silicone composition of the addition polymerization type, with cure by ultraviolet light which is curable at room temperature. The described silicone composition comprises a polydiorganosiloxane containing vinyl groups and a polydiorganosilane in which at least 4 silicon atoms are directly linked in the formula R5 (Si (R3) (R4)) "R6 in which R3-R6 are alkyl or aryl, and n is 4 or greater, with the proviso that R5 and R6 can be directly linked to each other. An addition polymerization catalyst is also included in the composition, such as a platinum catalyst. The composition is curable by ultraviolet light with the occurrence of radical addition polymerization. Hoffman, V., and collaborators J. Mol. Struct. , 293, 253-256 (1993) discloses oligomers that include a vinyl group containing dimethylsiloxane that are thermally crosslinkable as well as photochemically. Roth,., And collaborators, ^ Adv. ater , 2 (10), 497-498 (1990) describes a methylvinyl-dimethylsiloxane composition lacking photoinitiators, and undergoes radical cross-linking when exposed to laser radiation. Barrall, E., and collaborators, J. Polym. Sci., Polym. Svmp. 71, 189-202 (1984) describes ultraviolet-cured polydimethylsiloxanes containing pendant vinyl groups, wherein curing involves dicumyl peroxide-mediated vulcanization. U.S. Patent No. 4,064,027 to Gant discloses an ultraviolet light curable composition consisting essentially of a siloxane containing vinyl and silicon-bonded hydrogen atoms, containing siloxane, in which a mercaptofunctional silicone may be employed. as an accelerator of healing. U.S. Patent No. 4,742,092 to Inoue et al. And U.S. Patent No. 4,595,471 to Preiner et al. Show silicones curable by ultraviolet light and ultraviolet / dual moisture light employing silicones containing groups (metha) acryloxy and isopropenyloxy photocurable in combination with silicones containing mercapto. European Patent EP 0492828 describes ultraviolet light curable silicones of polydiorganosiloxanes terminated in alkoxy in combination with an alkoxy silicone compound which is capable of photoreactivity. However, this patent shows compositions wherein the silanol-terminated diorganopolysiloxane first reacts with only hydrolyzable groups containing capper ends. As a result, silicones do not end with groups activated by ultraviolet light. European Patent EP 0539234 relates to a composition for a liquid packing having both ultraviolet light curing property and a moisture curing property that is prepared by combining polysiloxane having at least one molecular group which can be met ( acryl), a polyorganosiloxane having silanol groups at both molecular ends, an organosilane having at least one hydrolysable group at one molecular end and a photopolymerization catalyst and a condensation catalyst. The compositions described in this reference are highly viscous, face a curing in volume and are inconvenient for shaped coatings. Japanese Patent Application No. 92143102 for Tokyo Three Bond Co. Ltd. describes moisture curable and ultraviolet light curable compositions of a composition prepared by adding polysiloxane relative to less reactive equivalent silane compounds having two or three hydrolyzable groups, methacryloyl groups or epoxy groups and reacting the composition with compounds having at least one vinyl group and methacryl groups and a wet cure catalyst. U.S. Patent No. 5,179,134 to Chu et al. Describes an acryloxy functional capped silicone which is formed as a. product of the reaction of a silyl diacrylate compound and a silicone having at least one functionality which is reactive with an acryloxy functionality of the silyl diacrylate compound to produce the functionally capped silicone by acryloxy. Accordingly, it would be a substantial advance in the art, and therefore it is an object of the present invention, to provide a vulcanizable silicone composition at room temperature that is easily "stable" at the application site following the application of the formulation at that site, so that the effects of migration (dropping, non-sticking, loss of sealing integrity of the joint, exposure of components that are intended to be encapsulated, etc.) are minimized or eliminated, but which is curable in a conventional manner under conditions of exposure to the ambient atmosphere for its wet cure and achieve superior complete healing properties. It would also be a substantial advance in the art, and it is therefore an object of the present invention, to provide a silicone coating composition formed dually curable by ultraviolet light and curable by moisture wherein the ultraviolet light curing of the composition gives as resulting in a coating that is dry to the touch without the common viscous surface often associated with a cure by acrylate. Another object of the present invention is to provide a vulcanizable silicone composition at room temperature, which is easily formulated in a convenient manner using resin and conventionally available formulation components. Still another object of the present invention is to provide an improved room temperature vulcanizable shaped silicone coating composition characterized in that it is conveniently formulated conveniently using conventionally available formulation components. Other objects and advantages of the invention will appear more clearly in the following description and the appended claims. COMPENDIUM OF THE INVENTION The present invention relates in general to silicone compositions curable by radiation and / or humidity. In a broad aspect the invention relates to a silicone composition curable by radiation and / or moisture, comprising: (A) a silicone formed as the reaction product of a silanol-terminated silicone and a silane crosslinker including a ethylenically unsaturated functional group and at least two hydrolysable functional groups, and (B) an effective photoinitiator for radiation curing of the silicone composition; wherein the silicone (A) is selected from the group consisting of: (I) silicones (A) whose silicone terminated in precursor reactive silanol has at least 60 mole percent Si-OH end groups and a viscosity at ambient temperature which does not exceed 1000 centipoise, and whose precursor silane crosslinker includes as the ethylenically unsaturated functional group a monovalent ethylenically unsaturated functional group, and wherein the silicone (A) is present in the silicone composition, in combination with a second silicone fluid , having both radiation-curable (meth) acryl functional groups and hydrolyzable functional groups curable by moisture, wherein the molar ratio of the ethylenically unsaturated groups against the (meth) acryl functional groups is from 5:95 to 4: 6; and (II) silicones (A), capped end with an ethylenically unsaturated functional group, having an average molecular weight number determined by nuclear magnetic resonance of at least 5000, and whose precursor silane crosslinker lacks mercapto functional groups and has this ethylenically unsaturated functional group and the at least two hydrolyzable functional groups together bound to a silicon atom of the silane crosslinker. A particular aspect of the broad invention described above refers to a vulcanizable silicone composition at room temperature curable by surface radiation which, after surface radiation treatment thereof, is characterized to be internally (under the surface or "layer"). curated by radiation of the composition) curable by moisture. This silicone composition vulcanizable at room temperature, of radiation-curable character on the surface, and subsequently internally curable by moisture, can conveniently comprise: (i) an end-capped silicone of ethylenically unsaturated functional group formed by the reaction of a finished silicone by silanol with a non-mercapto group containing silane crosslinker for the eicicone, and a photoinitiator to effect surface cure by radiation of the silicone composition. The crosslinker in this composition has attached directly to a silicon atom thereof an ethylenically unsaturated functional group and at least 2 hydrolyzable groups. The capped end silicone has an average molecular weight number of at least about 10,000, determined by nuclear magnetic resonance techniques. The silanol-terminated silicone used in the vulcanizable silicone composition at room temperature is preferably predominantly linear in character, locating the functionality of the silanol (-SiOH) at the end of a polysiloxy portion (- (S0) x-) in the silicone. The non-mercapto group containing the silane crosslinker in this composition can conveniently have the formula RaSiXb where: R is selected from the group consisting of monovalent ethylenically unsaturated radicals, 1 to 8 carbon atoms, aryl of 6 to 12 carbon atoms, arylalkyl of 7 to 18 carbon atoms, alkylaryl of 7 to 18 carbon atoms, and X; X is a monovalent functionality that imparts moisture curability to the reaction product of the silicone functionalized by silanol and the silane crosslinker; a has a value of 1 or 2; b has a value of 2 or 3; and a + b = 4 with the proviso that when a is 1, R is a monovalent ethylenically unsaturated radical, and that when a is 2, at least one R is a monovalent ethylenically unsaturated radical. Specific examples of monovalent ethylenically unsaturated R radical groups of the silane crosslinker include vinyl, propenyl, butenyl, pentenyl, hexenyl, octenyl, allyl, alkenyloxy, alkenylamino, allyloxy, allylamino, furanyl, phenyl, and benzyl groups. Illustrative species specific to the non-mercapto group containing the crosslinker include vinyltrimethoxysilane, vinyltriaminosilane, vinyltri-amidosilane, vinyltrioximinosilane, and vinyltriacetoxysilane. In another aspect, the invention relates to a packaging material for application to an encapsulation site. The encapsulation site includes a boundary surface delimiting a packaging volume in which an encapsulation structure can be arranged. By this configuration, the encapsulation structure can be packaged in a liquid medium superimposed by a coating layer adhesively bonded to the boundary surface. This packaging material comprises: (a) an end-capped silicone by an ethylenically unsaturated functional group having (i) no hydrolysable group, and (ii) an average molecular weight number of at least 5000 determined by nuclear magnetic resonance technique; and (b) an effective photoinitiator for the radiation surface cure of the silicone composition. In the use of this packaging composition, the packaging material is curable by the radiation of the material to form the cover layer covering the packaging material. Subsequent to the formation of this superposed cover layer, the packaging material underlying the cover layer is non-hydrolysable and remains in a liquid state. In yet another broad aspect, the present invention relates to a structural item of packaged element, comprising: a structural element defining an encapsulation site that includes a boundary surface that delimits an encapsulation volume; a structural element disposed in the encapsulation volume; a packaging means that encapsulates the structural element in the encapsulation volume, wherein the packaging means comprises a liquid silicone medium covered by a solid silicone film which wraps and is adhesively bonded to the boundary surface, so that the element is packaged in the liquid silicone medium, and the liquid silicone medium is contained in the encapsulation volume by the solid silicone film. The packaging means in such packaged article structural element conveniently comprises a radiation-curing packaging composition formed by radiation surface cure of a silicone composition comprising: a functional vinyl silicone lacking hydrolyzable groups; an effective photoinitiator for radiation surface cure of the silicone composition, wherein the packaging material is curable on the surface by the radiation of the material to form the cover wrap layer, after the formation of which the material of Packaging that is below the wrapping layer is not moisture curable. Yet another aspect of the present invention relates to a method for packaging an element in a structural encapsulation site that includes a boundary wall surface. This method includes: arranging this element in the encapsulation site; applying to the encapsulation site a silicone packaging composition as described hereinabove; and irradiating the silicone packaging composition at the encapsulation site, to superficially cure it and form a solid silicone layer of the wrapping packaging material that is adhesively bonded to the boundary surface, and to superimpose an uncured portion of the packaging material. In the packaging method described above, if the vinyl-finished silicone does not have hydrolyzable groups, then the composition not cured by radiation may be incurable by subsequent exposure to moisture. in that case, the packaging composition not cured by radiation is kept in an uncured condition, so that the structural element in the encapsulation site is packaged in the packaging composition not cured by radiation, and the packaging material not cured by radiation in turn is covered and retained physically or on position by the superimposed layer of the packaging material that cures the surface. Alternatively, the packaging composition not cured by radiation may be moisture curable, and the relevant packaging or manufacturing process may further comprise the moisture cure of the packaging composition not cured by radiation after the radiation passage. Another aspect of the composition of the present invention relates to curable, room temperature curable silicone compositions by ultraviolet light and moisture radiation, useful as conformal coating compositions. This silicone composition curable by radiation and moisture may conveniently comprise: (i) a first silicone fluid comprising an endcapped silicone of ethylenically unsaturated functional group which is a product of the reaction of a silicone terminated by silanol and a silane crosslinker having a monovalent ethylenically unsaturated functional group attached directly to a silicon atom thereof and when monkeys two hydrolyzable groups; (ii) a second silicone fluid comprising a silicone functionalized by (meth) acrylic, for example a silicone having both radiation curable (meth) aryl functional groups and hydrolyzable functional groups curable by moisture; and (iii) an effective photoinitiator for radiation cure of the silicone composition. In this silicone composition curable by radiation and moisture, the molar ratio of the ethylenically unsaturated groups against the (meth) acryl functional groups can be in the order of 5:95 to 4: 6. The silanol-terminated silicone in this radiation and moisture curable silicone composition preferably comprises a linear polydiorganosiloxane having a viscosity measured in a Brooksfield viscometer at room temperature (about 25 ° C) not exceeding about 1000 centipoise, preferably that does not exceed 750 centipoise and more preferably does not exceed approximately 200 centipoise. In the preferred silanol-terminated silicone of predominantly linear character, the silanol (-SiOH) is preferably functionally located at the end of a polysiloxy portion (- (SiO) x-) in the silicone molecule. Other aspects and features of the invention will become more fully apparent from the following description and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a partially sectional side view of an electronic fuel flow sensor assembly, packaged with a silicone composition according to one embodiment of the present invention. Figure 2 is a partially sectioned side view of an electronic fuel flow sensor assembly, packaged with a silicone composition according to another embodiment of the present invention.

DETAILED DESCRIPTION, AND PREFERRED MODALITIES FOR CARRYING OUT THE INVENTION The silicone compositions of the present invention utilize polysilane crosslinkers containing an olefinically unsaturated group or groups attached to the silicon atom of the crosslinker. This crosslinker by reaction with a silanol-terminated silicone (as shown in equation (1) hereinabove allows for the formulation of vulcanizable silicones at room temperature for packaging, shaped coating, or other applications, however, the present inventors also they discovered unexpectedly that the materials thus prepared, after the formulation with common photoinitiators such as diethoxyacetophenone, can undergo a slight cure (exposure to actinic radiation) to form a firm, non-viscous surface "cover" that possesses structural integrity, that is to say it is strong and non-migratory character, and protects the vulcanizable silicone composition at room temperature not cured underneath, but does not prevent moisture cure of the vulcanizable formulation at room temperature.

Thus, the ethylenically saturated silane-capped species, such as vinylmethoxysilane, vinyltrioxysilane and vinyltriacetoxysilane, were used to cap the ends of the silanol-terminated fluids, to form functional vinyl products such as the fluids terminated by vinyl dimethoxy, vinyl-dioximinoxy and vinyl diacetoxy, respectively. It was found that these fluids, after the addition of photo-cyclists, undergo ultraviolet light curing to form strong, non-viscous films. When they are exposed. to the convenient actinic radiation of a curatively effective nature, the resulting radiation-cured surface film is typically strong enough to protect., and to support the uncured liquid underlying film even when the substrate element that supports the silicone layer cured by radiation it is reversed in relation to its exposure position to the initial radiation. When these functional vinyl products are added to silicones functionalized by (meth) acrylic, after the addition of photoinitiators, these fluids undergo ultraviolet light curing to form strong, non-viscous films when exposed to convenient actinic radiation of a curatively effective nature. The resulting radiation-cured shaped coating is typically strong enough to provide the required protection to the substrate it covers. The inventors also discovered that exposure conditions at room temperature (generally, from about 0 ° C to about 30 ° C), atmospheric humidity (normal relative humidity (RH), for example, from about 2 percent to 100 percent percent relative humidity), can be used, after the aforementioned "light-induced coating cure", to effect moisture cure of the vulcanizable silicone material at room temperature below the radiation-cured cover stage and, surprisingly, the formation of the film cured by initial surface radiation does not change the hardness of the vulcanizable silicone at room temperature after this cure by final moisture. In the shaped coating applications, the silanol-terminated crosslinker / silicone reaction forms the monovalent ethylenically unsaturated functional end capped silicone. The composition comprising the ethylenically unsaturated functional group capped silicone and at least one silicone functionalized by (meth) acrylic provides a dual ultraviolet / moisture curable conformable coating composition having improved surface viscosity and relatively high cure time. . In a preferred embodiment, the silicone curable by radiation and humidity of the shaped coating composition of the invention comprises a first silicone fluid, a second silicone fluid and an effective photoinitiator for radiation curing of the silicone composition. Preferably the first silicone fluid comprises a reaction product of a silicone terminated by silanol having at least 60 mole% of Si-OH end groups and a viscosity, at room temperature, of 1000 centipoise or less, and a silane crosslinker which it has an ethylenically unsaturated functional group curable by radiation and at least two hydrolysable groups. The second silicone fluid preferably has both (meth) acrylic functional groups and hydrolyzable moisture curable groups. The molar ratio of the ethylenically unsaturated groups to the (meth) acryl functional groups is preferably from about 5:95 to about 4: 6 and more preferably from about 1: 5 to about 35:65. The present invention includes silicone compositions wherein the first and second silicone fluids are prepared at the same time from a silanol-terminated silicone having at least 60 mol% Si-OH end groups and a viscosity at room temperature , 1000 centipoise or less, and at least two silane re iculators. One of the crosslinkers has an ethylenically saturated radiation curable group, monovalent, and at least two hydrolysable groups, and at least one other eilane has a functional group of (meth) acrylic and at least two hydrolyzable groups. It has been unexpectedly discovered that even when the first and second silicone fluids, each has a viscosity that is preferably less than or equal to about 1000 centipoise and which in and of itself has poor light-curing capability when present in the silicone shaped coating compositions, after formulation with common photoinitiators, such as diethoxyacetophenone, these silicone fluids can undergo light cure (exposure to actinic radiation) in a relatively short period of time to form a non-viscous surface "layer", firm, that has structural integrity. In these coating applications the silicone compositions of the invention, as a result of their susceptibility to be cured by the incidence of radiation, as well as (or alternatively) by curing by vulcanizable moisture at room temperature, thereby allowing great flexibility in use, particularly in cases where the geometric or positional nature of the substrate or substrates to which the compositions are applied would otherwise cause opaqueness of the silicone composition from the source of actinic radiation. In these cases the applied silicone formed coating composition of the invention can be cured by moisture via the vulcanizable crosslinking at room temperature where the slow cure by moisture should be allowed to take place under conditions of exposure to normal atmospheric humidity. Alternatively, in cases where the applied silicone coated coating material is not susceptible to the opaque phenomenon, the material can be totally and only cured by exposure to actinic radiation. The composition of the present invention is curable under ambient temperature conditions, without any net addition or application of heat to this silicone composition. In this way the formulations of the present invention can be cured polymodally in. sequence, by initial actinic radiation, for example curing by ultraviolet light, and subsequent curing by moisture, and these silicone formulations are also curable in toto by moisture cure alone. In any case (polymodal cure involving superficial healing by initial radiation in sequence followed by moisture healing of the inner volume, or unimodal cure involving only moisture cure of the entire silicone formulation), the physical properties of the respective cured materials are substantially the same. The present invention, as a result of its susceptibility to be surface cured by the incidence of radiation, as well as (or alternatively) by curing by vulcanizable moisture at room temperature, by this allows great flexibility in use, particularly in cases where that the geometry or position of the substrate or the substrates to which the composition is applied would otherwise cause a detrimental drop or migration of the silicone composition before it can be cured by moisture - by vulcanizable crosslinking at room temperature. In these cases the applied silicone composition of the invention can be superficially cured selectively by exposure to radiation, in regions that are latently susceptible to falling or migrating or alternatively on the entire surface of the mass of the applied composition, and then it can allow slow curing by moisture to be carried out under conditions of exposure to normal atmospheric humidity. Alternatively, in cases where the applied silicone material is not susceptible to the phenomenon of fall or migration, the material can be completely and solely curable by exposure to humidity under conditions of relative humidity and normal ambient temperature. The composition of the present invention is curable under ambient temperature conditions, without any net addition or application of heat to the silicone composition. The invention can be very useful in many applications. For example, in compound packaging applications, after extruding a silicone packaging material according to the present invention, into the interior cavity or volume of the structure in which the component or components or other material or materials are To package for encapsulation thereof, the applied packaging material can be subjected to rapid light irradiation to form a firm film of low viscousity or without viscoeity, with sufficient strength to structurally lock the vulcanizable silicone composition at room temperature below of surface surface healing. The resulting packaged structural article can then be easily transported, while allowing moisture curing to take place during transport and storage of the article. In this way the packaging operation can be quickly concluded in the manufacturing facilities, so that the packaged items are immediately ready for transport and packaging, avoiding by this the substantial inventory of the uncured packaged items that in the previous practice has had to be substantially cured by moisture before this transport and packaging. The present invention may also be useful for forming non-viscous coatings that are not inhibited by the presence of oxygen, as is often the case with ultraviolet light curing involving the (meth) acrylate functional groups. In the silicone compositions, according to the invention, in which the silicone containing (meth) acryl functionality is present, there may be some inhibition between the (meth) acryl groups, but this phenomenon seems to be masked in these compositions by the presence of monovalent ethylenically unsaturated groups, especially vinyl groups. As used herein, the term "non-viscous" with reference to the surface of a mass of silicone composition subjected to radiation exposure, means that this surface is deformable, but resilient to the touch or non-adherent to, and not deformed by, the touch, that is, contact of a human finger with said surface. The present invention also contemplates the provision of a dual cure silicone composition comprising a dielectric gel of ultraviolet light cure / moisture cure, in applications in which ultraviolet radiation used to effect ultraviolet light curing is not accessible to the entire surface of the dielectric gel mass, so that the exterior of the mass includes regions accessible to radiation (direct incidence), as well as hidden regions that are blocked to the incidence of radiation (for example by housing structures or component structures packaged in packaging applications; by mask or other elements of layers of material in formed coating applications; etc) . In these applications of "hidden healing" of dielectric gel or other compositions of. The silicone of the present invention, both the regions of radiation curing, directly influencing / moisture curing of the composition matrix, and the hidden regions where only moisture cure is carried out, would exhibit physical and similar properties (e.g. hardness, resistance, thermal resistance, resistance to traction, re-entitlement to fracture, temperature stability, re-entitlement to compression, etc.) in the final cured material. The silicone shaped coatings of the invention can be cured by exposure to any radiation exposure condition that is curatively effective for the composition. Similarly, the photocurable eilicone compositions on the surface of the invention can be surface cured by exposure to any radiation condition that is curatively surface effective for the composition. Suitable types of radiant energy that can be usefully employed in the broad practice of the invention include electron beam radiation, ultraviolet radiation, visible light radiation, gamma radiation, x-rays, β-rays, and so on. Preferably, the photocurable radiation is actinic radiation, i.e. electromagnetic radiation having a wavelength of about 700 nm or less, which is capable of effecting the required cure, for example the surface cure of the silicone composition in the case of packaging or other volumes of silicone formulation of extended depth, or the curing of the total volume (in the case, for example, of thin shaped coatings) of the silicone composition. More preferably, the photocure radiation comprises ultraviolet radiation containing a wavelength of for example from about 200 to about 540 nm. It will be recognized that the type and character of the photocure radiation, for example, the surface healing radiation that is used to form a cured layer or film of the silicone composition maea of the present invention, after its application to the substrate or to another site of use, or the healing radiation of the whole body to cure an extended deep mass of the eicicone composition, ee may vary widely within the broad scope of the present invention, and that the curative times of exposure to the radiation in any given application with correspondingly variable, with respect to and depending on factors such as: the particular eyliconic formulation used, the type and light response of the specific photoinitiator used, the wavelength and the flux of variation, the concentration of the photoinitiator in the composition and thickness of the coating or other form of the applied composition mass. Generally the exposure time to the variation is relatively short, that is, less than about 3 minutes. Exposure of the composition to excessive amounts of radiation can "overcure" the composition, resulting in poor physical and performance properties. The amount of radiation that is excessive varies with the given formulation of the silicone composition, the coating thickness, the radiation source, etc., and can be easily determined by the skilled artisan even with proper experimentation. Similarly, the component of the radiation-cured layer that is effective to provide the required structural e? Ectability and the containment of the uncured underlying silicone composition (e.g., liquid or solid (eemi)) in a surface cure system, or to provide the required structural stability and protection of the substrate in a complete cure system, are easily determined within the skill of the art by simple and routine experimentation. Generally the shaped coatings are in the order of less than about 0.38 centimeters thick, typically from about 3 to about 0.025 centimeters thick. For example, the depth of cure required in a given end-use application can be established empirically by exposing corresponding amounts of the composition of separate substrate samples to vary amounts of radiation (or other parameters of variation, e.g. samples of respective composition of photoinitiator; o Quantity of filler; or diet between the applied composition maea and the source of radiation and so on) followed by the translation, inversion, etc. of the samples to determine which samples of the composition fall or migrate, for example, in the case of packaging or volume masses High depth of silicone formulation.

In the case of shaped coatings, the step of determining motif or susceptibility to migration or migration can be replaced by a corresponding step of touching the samples to determine which composition samples are viscous to the touch. The eilanol-terminated silicone used in the packaging or the volume-deposited silicone compositions of the present invention may conveniently comprise a linear polydiorganosiloxane, or other linear silicone, having an average molecular weight which may for example vary from about 1,000 to about 300,000, preferably from about 10,000 to about 80,000, and more preferably from about 10,000 to about 50,000. The silanol-terminated silicone which is preferably used to form the end-capped silicone by an ethylenically unsaturated functional group in the shaped coating compositions of the present invention may conveniently comprise a linear polydiorganosiloxane, or other linear silicone, which has an average weight of molecular weight which for example ranges from about 166 to about 20,000 preferably from about 500 haeta to about 12,000, and more preferably from about 800 to about 8,000. This silicone terminated by eilanol has a viscosity at room temperature (about 25 ° C) of monkeys or equal to about 1000 centipoise, preferably less than or equal to about 750 centipoise, and more preferably less than or equal to about 200 centipoise. Although this eyliconone is preferably linear in conformation, other nonlinear eiciconae, eg, branched, cyclic or macromeric, can be usefully employed in the broad practice of the present invention. Preferably, the silicone (polysiloxane) is predominantly linear in character. The silanol functionality (-SiOH) is located in the term of a polysiloxy portion (- (SiO) x-) in the silicone molecule, for example the hydroxy functionality is covalently bound to the terminal silicon atom of the polysiloxy central structure, in the case of a linear silicone, or a terminal silicon atom of a main or side chain or other aggregation of eyloxy repeating units in the case of a branched non-linear silicone molecular conformation or otherwise. Preferably, the polysiloxane is a linear molecule both of which groups are terminated to comprise hydroxy groups. Thus, for example, the polysiloxane material may comprise a hydroxy-terminated polydimethylsiloxane, or a hydroxy-terminated polydiphenylsiloxane. Preferably, the silicone is an organopolysiloxane whose organic substituents are predominantly methyl. A particularly useful polysiloxane material that has been used in the packaging of volume-deposited silicone compositions of the present invention is hydroxy-terminated polydimethylsiloxane of linear configuration, which has an average molecular weight weight determined by the chromatography technique. gel permeation in the order of 10,000 to 50,000. A particularly preferred polysiloxane material which has been useful for use in the formed coating compositions according to the present invention is hydroxy-terminated polydimethylsiloxane of linear configuration, which has an average molecular weight weight determined by the "magnetic resonance" technique. of the order of 4,000. The silane crosslinker which does not contain a mechapto group used in the compositions of the invention for the crosslinking of the eilanicone terminated in eilanol, as well as the silane crosslinker used in compositions of the invention to cover the ends of the finished silicone L itself to obtain the capped silanol by monovalent ethylenically unsaturated functional group conveniently comprises a silane compound having an ethylenically unsaturated functional group and at least two hydrolyzable functional groups attached directly to a silicon atom thereof. The silane crosslinker can for example have the formula RaSiXb wherein: R is selected from the group consisting of monovalent ethylenically unsaturated radicals, hydrogen, alkyl, 1 to 8 carbon atoms, aryl of 6 to 12 carbon atoms, arylalkyl of 7 to 18 carbon atoms, alkylaryl of 7 to 18 carbon atoms, and X; X is a monovalent functionality that imparts moisture curability to the reaction product of the silicone functionalized by silanol and the silane crosslinker; a has a value of 1 or 2; b has a value of 2 or 3; and a + b = 4 with the proviso that when a ee 1, R ee is a monovalent ethylenically unsaturated radical, and that when a is 2, at least one R is a monovalent ethylenically unsaturated radical. In this crosslinker formula, the monovalent ethylenically unsaturated radical can, for example, contain from 2 to 12 carbon atoms. The monovalent ethylenically unsaturated radicals for the crosslinker include vinyl, propenyl, butenyl, pentenyl, hexenyl, octenyl, allyl, alkenyloxy, alkenylamino, allyloxy, allylamino, furanyl, phenyl and benzyl groups. Preferably, the monovalent ethylenically unsaturated radical is selected from the group consisting of vinyl and allyl groups, and more preferably, the monovalent ethylenically unsaturated radical is vinyl. Specific illustrative species of the non-mercapto group containing crosslinker include vinyltrimethoxy silane, vinyltriaminosilane, vinyltriamidosilane, vinyltri-oximinosilane, vinyltriisopropenyloxysilane and vinyltri-acetoxysilane. As used in the preeent, the term "vinyl" refers to the group CH2 = CH-. The silane crosslinker ee can be used at any convenient concentration in the silicone composition of the present invention which is crosslinkingly effective for the silicone, as can be determined stoichiometrically in a direct manner within the skill of the art, or as can be empirically determined from easy way with the experience of the technique varying the concentration of the crosslinker in relation to the finished silica of silanol in the composition of eilicone, and crosslinking the composition in the presence of moisture, with and / or without surface healing by initial radiation of the composition. In conformal coating applications, for example, the amount of crosslinker is preferably less than slightly less to slightly more than the stoichiometric amount based on SiOH with the goal being to plug the ends of all available SiOH. By way of example, in the case of packaging or volume deposited compositions of the present invention using species of silane crosslinker such as vinyltrimethoxysilane, vinyltriaminosilane, vinyltriamido-silane, vinyltrioximinosilane, and vinyltriacetoxysilane, the concentration of crosslinker. is from about 1 percent to 10 percent by weight, based on the weight of the silicone-terminated silanol, and more preferably from about 1.5 percent to 5 percent by weight, on. same basis of the weight of eilicone terminated by silanol. In conformal coating applications utilizing the above silane crosslinker species or species such as vinyltriisopropenyloxysilane, the concentration of crosslinker is generally in the range of from about 1 percent to 50 percent by weight, based on the weight of the finished silicone. silanol. Compared to the compositions described in Bennington in U.S. Patent No. 4,526,955, which discloses the use of an organosilicon compound having an average of at least and preferably 3 or 4 groups per molecule having Si bonds. -N and / or Si-ON, the crosslinking eilanes used in the present invention comprise compounds having an ethylenically unsaturated functional group directly linked to a silane silicon atom and at least 2 hydrolyzable functional groups linked directly to a silicon atom of the silane, with this silane, and the resulting silicone product (polysiloxane) formed by the reaction of the crosslinker and the silicone functionalized by silanol, which has linked portions Si-C and / or Si-O-C. In the shaped coating applications of the invention, as well as in other applications, the composition may further comprise a capped silicone of non-reactive portion to modify the viscosity of the silicone fluid. The capped end silicones of non-reactive portions suitable for use in the present invention include, but are not limited to, silicone having an end cap of alkyl, aryl, arylalkyl and alkylaryl. An example of a capped end silicone of a specific non-reactive portion suitable for use in the invention is the trimethylylyl capped polydimethylsiloxane. In the compositions of the invention having utility for shaped coating compositions, the at least one silicone functionalized by (meth) acrylic has a functional group which is selected from the group consisting of the groups acryl, (meth) acryl, propenyl, butenyl , pentenyl, hexenyl, octenyl, allyl, alkenyloxy, alkenylamino, allyloxy, allylamino, furanyl, phenyl and benzyl, and at least one hydrolyzable group selected from the same hydrolyzable groups in the capped end silicones of monovalent ethylenically unsaturated functional group. Preferred functionalized silicones are silicone functionalized (meth) acryloxy or acryloxy alkyl or (meth) acryloxy or acryloxy alkenyl. Suitable silicones functionalized by (meth) acrylic for use in the present invention include, but are not limited to, silicone terminated by methacryloxypropyl dimethoxysilyl, silicone terminated by acryloxypropylmethoxysilyl or a mixture thereof. Silicones functionalized by (meth) acryl are known and can be prepared according to any known method including those exemplified in United States of America Patents No. 4,503,208; 4,504,629; 4,575,545; 4,575,546; 4,760,122; 4,290,869 and 4,595,471, the entire descriptions of which are incorporated herein by reference. The photoinitiator employed in the silicone compositions of the present invention may conveniently comprise a photoinitiator which may include any photoinitiator known in the art which is useful for photopolymerizing ethylenically unsaturated compounds (eg, vinyl or allyl) in the presence of curatively effective Potentially useful photoinitiators may include, by way of example, benzoin, substituted benzoins such as benzoin ethyl ether, benzophenone, benzophenone derivatives, Michler's ketone, dialcoxyacetophenones such as diethoxyacetophenone, acetophenone, benzyl, and other derivatives (substituted forms) and mixtures thereof. A particularly preferred photoinitiator material is diethyxyacetophenone. Although any convenient effective amount of photoinitiator can be employed in the photocurable surface-active silicone compositions of the invention, generally the concentration of photoinitiator will be usefully used in the range of about 0.1 percent to about 10 percent by weight, and more specifically and preferably from about 0.2 percent to about 5 percent by weight, based on the weight of the functional silicone per hydroxy. The photoinitiator employed in the photocurable compositions of the present invention may also be linked by polymer. These photoinitiators are described in U.S. Patent Nos. 4,477,326 and 4, 587,, 276. Other free radical initiators, such as peroxy thermal initiators, can be used in some of the lower molecular weight silicone formulations of the invention.

Moisture cure initiators suitable for use in various silicone compositions of the present invention include any of the initiators known in the art to include orthotitanate. The compositions of the present invention may also include other ingredients to modify the healing or non-healing properties of the composition as necessary or desirable for a specific end-use application. In cases where the species of silane crosslinker containing non-mercapto groups used in the present invention is vinyltrimethoxysilane, a catalyst may be necessary. Examples of curing catalysts include, but are not limited to, tin, titanium, aluminum, zirconium and any other convenient curing catalyst known in the art. Fillers or reinforcement materials may be usefully employed in compositions of the present invention to provide improved mechanical and, in some cases, surface curability by improved ultraviolet radiation properties of the composition. Among the preferred fillers are reinforcing silicones. Reinforcing silicones are smoked silicones that can not be treated (hydrophilic) or treated to make them hydrophobic.

In general, fillers can be employed at any convenient concentration in the curable silicone composition, but are generally present in concentrations of from about 5 to about 45 weight percent, based on the weight of the polysiloxane. Generally, any other mineral, carbonaceous, glass or ceramic filler can potentially be conveniently employed. Examples include ground quartz, tabular aluminum, diatomaceous earth, silicone balloons, calcium carbonate, carbon black, titanium oxide, aluminum oxide, aluminum hydroxide, zinc oxide, glass fiber, and the like. In addition, the silicone compositions of the present invention can optionally also contain an adhesion promoter, to increase the adhesiveness of the composition for a specific substrate (eg, met a 1, vi di, pottery, etc.) when the Composition is used as an adhesive to join elements or members of the same. Any adhesion promoter constituent can be employed for this purpose, depending on the specific elements or eubstrate members employed in a given application. For example, the adhesion promoter could be chosen to increase the adhesion of the composition to substrates comprising materials such as metals, glasses, ceramics, plastics, and mixtures, fuels, compuets, and combinations (or the same.) Various organosilane compounds can be used. useful for this purpose, and these compounds may also have oxirane functionality, such as silicon-bonded alkoxy substituents, to provide extensive adhesive bonding utility., functionality a can provide a glycidoxial substitute than a silicon atom of the silane compound. A particularly preferred adhesion promoter of this type is g 1 i c idox i ropi 1 t i i methoxysilane. In addition, other additives such as MU or MD resins may be incorporated, to vary the properties of the eylicon composition as desired. In addition to the constituents identified above as optionally included in the silicone compositions of the present invention, other optional constituents include anti oxidants, flame retardants and pigments, and so on, as well as free-flowing adjuvants, for example those which are optional. at an filler such as hydroxy-terminated vinylmethoxysiloxane, for the treatment of quartz filler or similar fillers when used in the composition. With respect to other filler components of the silicone compositions of the present invention, it will be appreciated that the use of filler materials can significantly alter the depth of the surface cure of the composition mass, and the fillers can therefore be used in a manner useful to achieve a desired cured layer thickness on the outer surface of the composition mass. The surface cure by radiation exposure of the silicone compositions of the present invention may be conveniently carried out in an ambient atmosphere or in an inert atmosphere such as nitrogen or argon. Moisture cure of the moisture curable compositions of the present invention is typically conveniently carried out under ambient air exposure conditions, but this cure can alternatively be carried out in a cabinet with high humidity or other high temperature synthetic environment. moisture for the period of curing by moisture required, which can easily be determined within the skill in the art with regard to the determination of the moisture-curing properties of the final product. The silicone compositions of the present invention utilize components that are readily synthesized within the skill in the art, and / or are readily available in the market. To make the silicone compositions of the present invention, the silicone component terminated in silanol and the non-mercapto group containing silane crosslinker can be reacted with each other at room temperature, for example at room temperature in the range of 20 ° C - 30 ° C for long enough to complete the reaction, typically 0.5 to 4 hours. Alternatively, elevated temperature can be used to accelerate the reaction rate, however, ambient temperature conditions are generally satifactory and are preferred to facilitate synthesis. The reaction mixture may optionally, if desired, include a convenient catalyst, such as an organometallic compound (eg, butyl lithium) to facilitate the reaction between the silanol-terminated eicicone reagent and the silane crosslinker. After the desired duration of reaction, the catalyst ee can be dampened, for example by the addition of acid in the case of organometallic reagents. After the reaction between the finished silicone reagent in eilanol and the silane crosslinker has been carried out, the product of the silicone fluid reaction is simply mixed with the photoinitiator for the subsequent exposure of the resulting composition to the photopolymerisingly effective radiation to cure (superficially or by volume) the composition.

In this way the product of the silicone fluid reaction can be mixed with the photoinitiator under conditions of non-exposure to radiation, and the resulting mixed composition can be stored in containers that do not transmit photopolymerisingly effective radiation, as a single package composition for later use. Alternatively, the product of the silicone fluid reaction can be used as a two-part or two-pack system, in which the product of the silicone fluid reaction is mixed with the component to be used at the time of use. , immediately before the application thereof on the use site, and of the curatively effective radiation of the applied mixed composition. The silicone compositions, at least partially silicone curable of the present invention can be formulated in a variety of ways for convenient use in any variety of applications including use as sealant, adhesive, encapsulating compounds, impact or shock absorbing means, coatings shaped, etc. In some applications of the present invention, as described more fully hereinbelow with reference to Example 7 herein, it may be desirable to formulate the silicone composition surface-curable by radiation so that the film surface-cured by radiation of the composition it will be moisture transmitting, but the ethylenically unsaturated functional group capped silicone does not have hydrolyzable groups, so that moisture curing of the underlying composition not cured by radiation is not carried out. These compositions can be used for coating, encapsulating or other applications, in which it is desired to provide a solid cured silicone film (layer) superimposed on uncured silicone liquid. In packaging applications, for example, this mass of the composition, comprising a surface-cured surface capable of retaining the underlying liquid at the packing site by adhesive bonding of the solid cured silicone surface layer to the surface or Frontier surfaces of the packaging site, can protect the packaged element, for example an electromechanical mechanism in the underlying liquid. The underlying liquid consequently functions as a means of fluid damping which may in fact be superior to solid packaging materials to secure the packaged element against damage or displacement which might otherwise arise in cases where the assembly of the Packaged element is subjected to impact, shock, vibration, and so on.

Figure 1 shows a partially sectioned side view of an electronic fuel flow sensor assembly, packaged with a silicone composition according to an embodiment of the present invention. The sensor assembly 62 comprises a housing 64 in which a solenoid element 66 is disposed. The solenoid element is connected to a suitable electronic coupling element for the connecting elements. female 71 which allows the seneor assembly to be installed in an automotive electronic system to monitor fuel flow. The sensor assembly comprises an inlet port 68 and an outlet port 70 provided for the flow of fuel through the device. In the housing of the sensor assembly there is an interior space 72 surrounding the solenoid element 66 and its associated electronic coupling element, to which the packaging composition of the invention can be introduced and cured in sequence as described above. The packaging mass comprises a radiation-cured top surface 102 which is a cured silicone solid film or layer, and which at its periphery is adherently bonded (bonded) to the side walls of the housing 64. By this configuration, the surface cured by radiation 102 is eobreposed, and covers (together with the side walls of the housing), the uncured liquid silicone composition 100. If the surface 102 is permeable to moisture in character, but the liquid silicone is not moisture curable as described more fully later in the present in relation to Example 7 hereof, then the silicone liquid 100 is permanently maintained in the liquid state, and constitutes a liquid packing medium for the solenoid element 66 and the structure of associated elements. Figure 2 is a partially sectioned side view of a corresponding electron fuel flow sensor, packaged with a silicone composition according to another embodiment of the present invention. The corresponding parts and elements are numbered in Figure 2 with the same reference numerals used in Figure 1. In the embodiment of Figure 2, the packaging composition comprises the surface layer surface-cured by radiation 102 superimposed on the mass of moisture-cured silicone .100 which surrounds and encapsulates the solenoid element 66 and the structure of associated elements. In this embodiment of Figure 2, the upper layer 100 subsequent to the formation of the surface cure by radiation thereof remains permeable to moisture, so that the transmission of moisture through the euperior layer 102 has given as a result moisture cure of the underlying packaging material 100 to a solid state. In the embodiments of Figures 1 and 2, the surface layer 102 can be of the order of 0.025 to 0.152 centimeters, depending on the type and character of radiation used to effect the formation by curing them. The radiation and moisture curable silicone compositions of the present invention then have a rapid and convenient element for packaging an element, in which the initial exposure to the radiation forms a solid surface layer which allows subsequent moisture cure the composition of eilicone eubyacente, but which at the same time allows the immediate handling, transport and storage of the packaged item cured superficially. If this possibility of immediate handling is not required, the entire mass of the composition can be completely cured by moisture, without the record of radiation exposure to form the upper surface layer. The features and advantages of the invention are more fully illustrated in the following non-limiting examples, wherein all parts and percentages are by weight, unless otherwise expressly stated.

EXAMPLE 1 Five hundred ninety-four grams of a silanol-terminated polydimethylsiloxane fluid with an average molecular weight of 18,000 (gel permeation chromatography) were reacted with 10 grams of vinyltrimethoxysilane using a butyl lithium catalyst for 2 hours. The catalyst was then buffered with acid. The material thus obtained is a silicone fluid terminated by vinyl dimethoxy. To 20 grams of the above fluid were added 0.30 grams of diethoxyacetophenone and 0.10 grams of titanium tetraisopropoxide and the resulting composition (hereinafter referred to as "Base Composition") was mixed thoroughly. The Base Compound mixture was separated into two equal fractions and poured into aluminum plates. One of these fractions, denoted here as Sample A, was subjected to ultraviolet light radiation using a Fusion System ultraviolet light source with a light intensity of -75 milliwats per square centimeter (m / cm2) for one minute. The irradiated material formed a non-viscous surface surface having a pale yellowish tint, and with uncured liquid enclosed below the surface. The tentative determination of the hardness of the material using a Durometer (00) meter did not record a reading (hardness 0). However, the surface film was firm enough so that the Durometer meter needle did not penetrate (break) the film. The inversion of the aluminum plate did not cause the liquid enclosed in the film to spill through it to break the film. The other of the fractions, denoted here as Sample B, was not superficially cured by radiation or otherwise exposed to curatively effective radiation. Both samples were cured by humidity during the night and readings were taken with Durpmeter (00) the next day for each one. The Durometer value (00) measured for Sample A was 70 and the Durometer value (00) measured for Sample B was 67. As a comparison, the basic composition of s? modified by adding only 1.5 percent detoxyacetophenone and without titanium tetraisopropoxide therein (hereinafter denoted "Modified Composition A"). Modified Composition A was cured by ultraviolet radiation (using the radiation system member described above) to produce a firm layer of non-viscous surface with liquid encased in it. However, the enclosed liquid would not be cured by moisture. The inversion of the aluminum plate did not cause the liquid to spill through the cover. As another comparison, a mixture of 594 grams of the above silanol-terminated fluid and 10 grams of the vinyltrimethoxysilane was made. Twenty grams of this mixture was formulated with 0.30 grams of detoxyacetophenone. The formulated mixture (hereinafter referred to as "Modified Composition B") was subjected to the same ultraviolet light radiation system as that described above and only a very thin layer of viscous surface was obtained. The inversion of the aluminum plate caused the liquid below the surface to spill through the thin surface. The surface was easily removed by touching it with your finger. As yet another comparison, 370.4 grams of the same silanol fluid was reacted with 5.6 grams of methyltrimethoxysilane using butyl lithium catalyst for 2 hours. The catalyst was then buffered by acid. The material thus obtained was an eylicone fluid terminated by methyldimethoxy. To 20 grams of this fluid, he added 0.30 grams of diethyxyacetophenone. The resulting mixture (hereinafter denoted "modified composition C") was subjected to the same ultraviolet light radiation system as described above. Only a very thin surface layer or film was formed. By inverting the container of the mixture after curing with ultraviolet light it caused the enclosed liquid to flow through the thin film immediately. The film in it was so weak that when I touched the film lightly, it caused the film to rise out of the liquid.

EXAMPLE 2 Twenty grams of fluid terminated by silanol with a molecular weight of 18,000 was mixed with 0.72 grams of vinyltrioximinosilane [CH 2 = CHSi (ON = CMeEt) 3]. The mixture was further formulated with 0.30 grams of diethoxyacetophenone and 0.10 grams of dimethyl tin bis (neodecanoate). The mixture was separated into two equal fractions, hereinafter denoted as "Mues" tra C "and Sample D", respectively, The Molecule C ee subjected to ultraviolet light curing as described in Example 1 while Sample D ee cured by moisture.The ultraviolet light-cured C-unit was an initial pale yellowish gel with a firm, non-viscous surface with fluid under the gel.The film was firm enough so that when the aluminum plate was inverted, it was not spilled liquid encased through the film As a comparison, vinyltrioximinosilane was replaced by methyltrioximinosrl not in the formulation process described above and the resulting composition (Mueetra E) was irradiated with the same ultraviolet light curing process as Sample C produced a material with a very thin, viscous surface that was easily lifted by lightly touching the surface with the fingers. pour the dish, the liquid under the surface immediately flowed through the film.

EXAMPLE 3 Twenty grams of the fluid terminated by silanol with an average molecular weight of 18,000 was mixed with 0.72 grams of vinyltrioximinosilane. To this mixture was added in addition 0.80 grams of ethyltriacetoxysilane, 0.30 grams of diethyxyacetophenone, and 0.10 grams of dimethyliso tin neodecanoate.The formulation was listed in doe denoted hereafter as Sample F and Sample G, Sample F was subjected to ultraviolet light curing as described above for Sample C. The mixture formed a firm, non-viscous surface film layer after curing by ultraviolet light. No liquid was spilled through the sample. The film when the aluminum plate containing the surface cured material was inverted, both Sample F and Sample G were cured by humidity for 72 hours, after which the Durometer (00) value was determined. F and G gave Durometer (00) readings of 60. For comparison, the order of addition of vinyltrioximinosilane and ethyltriacetoxysilane was invested in the process above, and the resulting material (Sample H) after curing by ultraviolet light (by the same radiation procedure as that of Mueetra C) formed a very thin viscous film that was easily lifted with the touch of a finger. By inverting the aluminum plate containing this surface-cured material, an immediate flow of the liquid through the film was caused. This formulation was then cured by humidity for 72 hours, producing a cured silicone material that had a hardness value in the Durometer (00) of 60.

EXAMPLE 4 Vinyltriacetoxysilane (0.47 grams) was added to 20.74 grams of silicone fluid terminated by eilanol with an average molecular weight of 20,000. To this mixture was added 0.30 grams of diethoxyacetophenone and 0.10 grams of dimethyl tin bis (neodecanoate). The formulation was thoroughly mixed and deaerated. The resulting mixture was then separated into two equal fractions denoted herein as Sample I and Sample J. Sample I was cured by ultraviolet light by the same radiation method as that described above for Sample C to produce a cured silicone material. superficially it had a firm non-viscous surface which was strong enough to hold the uncured liquid below the surface when the aluminum plate was inverted. Both Sample I and Sample J were cured by moisture overnight to form a cured silicone rubber product. Both cured materials (Sample I and Sample J) had the same hardness value in the Durometer (00) of 73. EXAMPLE 5 Silanol-terminated polydimethylsiloxane fluids with an average molecular weight of 20,000 were partially capped at the end with trimethylchlorosilane and hexamethyldisilazane. The resulting fluids were filtered and capped at the ends with vinyltrioximinosilane. Fluids after the addition of 1.5 percent diethoxyacetophenone and 0.5 percent bis (neodecanoate) dimethyl tin were found to be surface curable by ultraviolet light (using the radiation method described for Sample C) to produce a material of irradiated silicone that has a non-viscous surface. It was determined that these formulations were also moisture curable to form silicoiumes. It was found that the hardness of the gums of the cured product was completely correlated with the levels of trimethylsilyl end groups. Specifically, the higher the trimethylsilyl level in the formulation, the softer the gum from the cured product. It was found that the hardness of the rubber samples of the cured product was not related to the curing mode. Thus, both the dual cure (ultraviolet / moisture) silicone rubber products and the silicone rubber products cured only by moisture exhibited similar hardness levels as shown in Table I below. TABLE I HARDNESS VALUES FOR CURED SAMPLES IN SEQUENCE BY INITIAL EXPOSURE TO ULTRAVIOLET LIGHT FOLLOWED BY HUMIDITY CURE (DUAL HEALING), AGAINST CURED SAMPLES COMPLETELY ONLY BY HUMIDITY CURE (MONOCRUIDE) EXAMPLE 6 The formulation process of the silicone composition of Example 5 was repeated using the following photoinitiators in place of dietoxyacetophenone: Darocur 1116 ((CH3) 2HC6H4C = OC (CH3) 2OH), 1173 (2-hydroxy-2-methyl) l-phenyl-propan-l-one), 1664 (owner, EM Industries), and 2273 (owner, EM Industries).

In all cases the radiation of the compositions applied to the substrate (aluminum tray) by the radiation procedure of Example 1 produced surface-cured radiation materials having films of non-strong surface layers with characteristics similar to those obtained using the photoinitiators of Example 5.

EXAMPLE 7 A vinyl-terminated silicone polymer having an average molecular weight of 93,000 ee formulated with 1.5 percent diethoxyacetophenone. The resulting silicone material after ultraviolet light radiation formed a gel with liquid under a surface cover layer. This material, however, would not be cured by moisture. This composition illustrates an embodiment of the invention that may be useful in cases where the formation of a strong and physically continuous film of a fluid is desired to send the underlying (uncured) fluid to migrate. The silicone composition of this Example can thus be used as a packaging material, in which the silicone composition is applied in a housing containing a mechanism, structural element, or other material (or materials) for the encapsulation of the honeycomb. . After application, the composition is irradiated with curatively effective radiation on the surface to form a stable cover layer fixedly, firmly on the upper surface of the encapsulation mass. Under this superposed cured silicone layer, contained by the front surfaces of the housing, is the uncured liquid silicone composition. The underlying liquid, as a result of its confinement by the surface cured cover and the surfaces of the boundary cavity to which the cover is adhesively bonded, functions as a fluid encapsulation and shock damping system. As a result of this viscous damping character, the uncured packaging material contained by the superposed cured layer of packaging material is markedly superior to the solid packaging (fully cured resin) compositions of the prior art., with respect to protecting the encapsulated structure of material from damage or displacement that may occur otherwise due to shocks, vibration, impact, etc. exerted on the encapsulation system (packaging). In addition, the "liquid packaging" formulation of the invention is not subjected to differential thermal expansion effects that adversely affect solid packing masses by making cracks and stress fractures and the tensile, compressive and torsional forces associated in the mechanisms or elements that are being encapsulated by the packaging means. For these reasons, the liquid packaging structure of the present invention, comprising a cover healed by surface radiation and an underlying uncured liquid, in a cavity or other containment site, is a remarkable advance in the packaging and encapsulation technique.

EXAMPLE 8 Forty grams of 100 centipoise (Brooksfield viscometer) of silanol-terminated polydimethylsiloxane fluid with an average molecular weight number of 5,000 (nuclear magnetic resonance) was mixed (capped) with 5.00 grams of vinyltris (methylethylketoximino) silane. The initially cloudy mixture cleared up in a matter of seconds when the end cap was finished. To the mixture was further added 0.675 grams of diethoxyacetophenone. To an aluminum plate with a diameter of 65 millimeters, 0.5 grams of the previous formulation was added. The material was left to distribute to cover the entire plate. The thickness of the coating cover was approximately 0.015 centimeters. Ultraviolet light radiation from the coating using a Fusion System lamp (medium pressure mercury lamp) at a radiation flow of approximately 75 milli ats / square centimeter for one minute resulted in a soft cured silicone coating that was dry to the touch . The coating will also be cured by moisture to give a strong silicone coating. In contrast, when methyltrie- (methylethylketoximino) silane was used in place of yinyltris (methylethyl ketoximino) silane in the above formulation, the resulting material showed no ultraviolet light curing ability under identical cure conditions. The material remained liquid after trying to cure by ultraviolet light. The material was cured by moisture for a silicone coating after remaining a few hours.

EXAMPLE 9 Six hundred grams of 40 centipoise (Brooksfield viscometer) of silicone fluid, 80 percent of which had terminal ends of silanol and 20 percent of which had trimethylsilyl ends and was mixed with two hundred and fifty seven branches of methacryloxypropyltrimethoxyethylane in a reactor with nitrogen dispersion. Butyl lithium catalyst (1.6 M, 0.36 grams) was added to the mixture. The mixture was stirred with nitrogen dispersion for 90 minutes and then dispersed with carbon dioxide for 30 minutes. The mixture was removed under vacuum at 70 ° C for one hour to obtain a silicone fluid terminated at 80 percent by methacryloxypropyl dimethoxy and terminated at 20 percent by trimethylsilyl and designated Fluid M.

EXAMPLE 10 Two hundred forty-one grams of 40 centipoisee silicone fluid with 80 percent endings terminated by silanol and 20 percent ends by trimethylsilyl was allowed to react with ninety grams of acryloxypropyltrimethoxysilane in the presence of 0.5 milliliters of butyl lithium (1.6M) according to the procedure presented in Example 9 to obtain a silicone fluid terminated at 80 percent by acryloxypropylmethoxysilyl, and terminated at 20 percent by trimethylsilyl designated as Fluid A.

EXAMPLE 11 Two hundred and fifty seven grams of the 40 centipoise silicone fluid with 80 percent ends terminated by silanol and 20 percent endings terminated by trimethylsilyl were allowed to react with 61.7 grams of vinyltrimethoxysilane in the presence of 0.2 milliliters of butyl lithium (1.6 M) according to the procedure set forth in Example 9 to obtain an 80 percent silicone fluid terminated by vinyl dimethoxysilyl, 20 percent terminated by trimethylsilyl designated Fluid V.

EXAMPLE 12 Two hundred and sixty grams of the 40 centipoise silicone fluid with 80 percent ends terminated by silanol and 20 percent endings terminated by trimethylsilyl was allowed to react with 35 grams of methacryloxypropyltrimethoxysilane, 33 grams of acryloxypropyltrimethoxysilane and 21 grams of vinyltrimethoxysilane. in the presence of 0.3 milliliters of butyl lithium (1.6 M) according to the procedure described in Example 9 to obtain a silicone fluid of approximately 27 percent of methacryloxypropyl dimethoxy-ethyl ends, 26 percent of acryloxypropyl dimethoxysilyl ends, 27 percent vinyl dimethoxysilyl ends and 20 percent trimethylsilyl ends, designated Fluid MAV. Example 12 incorporates an alternative method for the preparation of the compositions of the present invention wherein the first and second silicone fluids are prepared at the same time by an appropriate eilanol or silanol mixture and the first silane having an ethylenically unsaturated group, radiation curable, monovalent and at least two groups hydrolysable and when less another silane having a functional group (meth) acryl and at least do hydrolysable groups. It is recognized that a silicone fluid can have both an ethylenically unsaturated radiation curable group and a radiation curable (meth) acryl functional group. However, due to the molar proportion of these portions, when some of the silicone fluids having the (meth) acryl functional groups do not ... they will have the ethylenically unsaturated group. The molar ratio of the eilanes depends on the level of monovalent, radiation-curable ethylenically unsaturated groups desired, the total amount of silanes being about the stoichiometric amount relative to the SiOH functionality of the initial silanol fluid.

EXAMPLE 13 Seven sample formulations were prepared (Samples 1-7) wherein the silicone fluids, obtained from the procedures set forth in Examples 9-12, were included in different proportions as described for each sample in the Table II later. A 6.5 percent amount of diethoxyacetophenone based on the weight of total silicones was added to each sample as a photoinitiator. Approximately 0.5 grams of each mueetra formulation was poured into an aluminum dish approximately 65 millimeters in diameter. The material was distributed to cover the entire base of the plate to a thickness of approximately 0.013 centimeters. The coating was subjected to ultraviolet radiation using a Fusion System ultraviolet light source with a light intensity of -60 milliwats per square centimeter (m / cm2) for various durations as presented in Table II. The viscosity of the resulting ultraviolet cured coatings was determined by lightly tapping the coating with a finger. The number from 0 to 5 was then assigned to each coating. The degree of number denotes the viscosity of the cured surface and is defined as follows: 0 = no cure 1 = some thickening of the coating fluid, the surface is still covered with liquid. 2 = significant thickening of the fluid, when touched, the fluid momentarily maintains a fingerprint mark, 3 = the coating cured as rubber, leaves a fingerprint mark when touched, 4 = the coating is cured but viscous, = the coating is completely cured with a dry surface to the touch. The sample formulations used and their viscosity performances at different levels of cure are shown in the following Table II TABLE II The results presented in Table II indicate that the presence of Fluid V results in a much better surface cure than that of Fluid M itself (Sample 1) or Fluid A itself (Sample 6). However, Fluid V itself (Mueetra 5) had low performance. The best performance was with the M1AV Fluid (Sample 7).

EXAMPLE 14 Some formulations of additional samples were prepared (Samples 8-14) wherein the silicone fluids obtained from the procedures presented in Examples 9-12 were included in different proportions as presented for each sample in Table III below. Diethyxyacetophenone, in an amount of 6.5% based on the weight of total silicones, was added as a photoinitiator and tetraisopropyl tetanyte was added as a moisture cure initiator. Each formulation coating was subjected to ultraviolet cure according to the procedure presented for samples 1-7 in Example 13 above. The samples were allowed to cure by moisture to non-viscous coatings. The surface was viscously immediately after curing by ultraviolet light, but moisture curing was previously determined as written in Example 13. The formulations for samples 8-14 and performances are presented in Table III below. .

TABLE II The results presented in Table III indicate that the partial replacement of the Fluid M by the Fluid V resulted in a much more improved edemal cure than that of the fluid M even when the same Fluid V lio cured the surface (Sample 12). The overall results were that the presence of vinyl provided a faster cure to touch cure. It is believed that the presence of catalyst to cure by moisture combined with photocuring increased the surface cure of the acrylate and methacrylate compositions. Even though the acrylate composition seems to perform almost as well as the vinyl-containing compounds, the resins do not have environmental, health and safety problems associated with functional silicone by acryl.

INDUSTRIAL APPLICABILITY OF THE INVENTION The radiation and moisture curable silicone compositions of the present invention have utility as sealants, adhesives, coatings, packaging compositions, and the like. In these applications the curability of the silicone composition allows the easy application and curing of the eylicon material and correspondingly the easier handling and further processing of the structure surfaces, parts and assemblies with which the silicone composition is employed. In addition, the liquid packaging application described herein may be used to package the mechanical and / or electrical assemblies, in a manner that uses the uncured packaging material as a viscous damping medium. This packaging configuration minimizes the susceptibility of the packaged structural element to being damaged or malfunctioning by shock, transfer and impact of the packaged assembly. Although the invention has been described illustratively herein with reference to several preferred features, aspects and embodiments, it will be appreciated that the invention is not so limited, and may vary widely with respect to variations, modifications and other alternative embodiments and therefore both the invention can be interpreted as including these alternative variations, modifications and other modalities, within the spirit and scope of the invention as claimed.

Claims (46)

1. CLAIMS 1. A silicone composition curable by radiation and / or humidity which when exposed to radiation cures the surface to form a firm surface covering layer covering a moisture curable interior volume of the composition, this composition comprises: (A) a silicone formed as the product of the reaction of a silanol-terminated silicone and a silane crosslinker including an ethylenically unsaturated functional group and at least two hydrolyzable functional groups, and (B) an effective photoinitiator for radiation curing of the silicone composition; wherein the silicone (A) is selected from the group consisting of: (I) silicones (A) whose silicone terminated in precursor reactive silanol has at least 60 mole percent Si-OH end groups and a viscoeity at room temperature which does not exceeds 1000 centipoisee, and whose precursor silane crosslinker includes as the ethylenically unsaturated functional group a monovalent ethylenically unsaturated functional group, and wherein the silicone (A) is present in the silicone composition, in combination with a second silicone fluid, having both radiation-curable (meth) acrylic functional groups and hydrolyzable functional groups curable by moisture, wherein the molar ratio of the ethylenically unsaturated groups against the functional groups (meth) acryl is from 5:95 to 4: 6; and (II) silicones (A), capped end with an ethylenically unsaturated functional group, having an average molecular weight number determined by nuclear magnetic resonance of at least 5000, and of which, the precursor silane crosslinker lacks mercapto functional groups and it has this ethylenically unsaturated functional group and the at least two hydrolysable targeting functional groups attached to a silicon atom of the silane crosslinker.
2. 2. A silicone composition according to claim 1, said precursor silane crosslinker has the formula: R., SiXb wherein: R is selected from the group consisting of monovalent ethylenically unsaturated radicals, hydrogen, alkyl of 1 to 8 carbon atoms, carbon, aryl of 6 to 12 carbon atoms, arylalkyl of 7 to 18 carbon atoms, alkylaryl of 7 to 18 carbon atoms, and X. X is a monovalent functionality that imparts moisture curability to the product of the silicone reaction terminated by silanol and the silane crosslinker; a has a value of 1 or 2; b has a value of 2 or 3; ya + b = 4 3. A silicone composition in liquid phase vulcanizable at room temperature surface curable by radiation forms a solid surface layer superimposed on uncured liquid of the composition, and which after surface curing by radiation thereof , it is of a moisture curable character internally in the uncured liquid covered by the solid surface layer formed by the exposure to radiation, the vulcanizable silicone composition comprising at room temperature being surface curable by radiation, subsequently internally curable by moisture: a silicone end capped with ethylenically unsaturated functional group wherein the capped end silicone is formed by reacting a silicone terminated by silanol with a non-mercapto group containing silane crosslinker for the silicone, the crosslinker having attached directly to a silicon atom thereof a ethylenic functional group unsaturated and at least two hydrolysable functional groups and capped silicon have an average molecular weight number of at least about 5000 determined by nuclear magnetic resonance; and an effective photoinitiator for the surface cure by radiation of the silicone composition. 4. A composition according to claim 3, wherein the capped end silicone has an average molecular weight number of at least about 10., 000 A composition according to claim 3, wherein the silicone terminated by silanol comprises a linear polydiorganosiloxane having an average molecular weight weight of from about 5,000 to about 300,000 determined by gel permeation chromatography. 6. A composition according to claim 3, wherein the silicone terminated by silanol is predominantly linear in character, having the silanol functionality (-SiOH) located at the end of a polysiloxy portion (- (SiO) x-) in the molecule of sylicon. A composition according to claim 3, wherein the silicone terminated by silanol is a linear molecule where both of its terminal functional groups comprise hydroxy groups. 8. A composition according to claim 3, wherein the silicone terminated by silanol is an organopolysiloxane whose organic substituents are predominantly methyl. 9. A composition according to claim 2, wherein the monovalent ethylenically unsaturated radical contains from 2 to 12 carbon atoms. 10. A composition according to claim 2, wherein the monovalent ethylenically unsaturated radical is selected from the group consisting of the groups vinyl, propenyl, butenyl, pentenyl, hexenyl, octenyl, allyl, alkenylaxy, alkenylamino, allyloxy, allylamino, furanyl, phenyl and benzyl. 11. A composition according to claim 2, wherein the monovalent ethylenically unsaturated radical is selected from the group consisting of the vinyl and allyl groups. 12. A composition according to claim 2, wherein the monovalent ethylenically unsaturated radical is vinyl. 13. A composition according to claim 3, wherein the silane crosslinker is selected from the group consisting of vinyltrimethoxysilane, vinyltriamine-silane, vinyltriamidosilane, vinyltrioximinosilane, vinyltri-isopropenyloxysilane and vinyltriacetoxysilane. 14. A composition according to claim 1, wherein the photoinitiator is selected from the group consisting of benzoin, benzophenone, Michler's ketone, dialkoxy acetophenones, acetophenone, benzyl, and derivatives and mixtures thereof. 15. A composition according to claim 1, wherein the photoinitiator is dietoxyacetophenone. 16. A composition according to claim 1, wherein the photoinitiator has a concentration of from about 0.1 percent to about 10 percent by weight, based on the weight of the silicone terminated by silanol. 17. A liquid phase silicone packaging material surface curable by radiation to be applied to an encapsulation site including a boundary surface delimiting a volume in which an encapsulation structure is available for packaging in a liquid medium covered by a wrapping layer adhesively bonded to the boundary surface, wherein the packaging material after exposure to radiation forms a solid surface layer that constitutes the cubitite layer, covering the uncured liquid of the packaging material, and where the packaging material after surface radiation treatment thereof comprises internally uncured liquid as a liquid medium, the packaging material comprising: an end-capped silicone with ethylenically unsaturated functional group wherein the end-capped silicone is formed by the reaction of a silicone finished by silanol with a group or non-mercapto containing silane crosslinker for the silicone, the crosslinker having attached directly to a silicon atom thereof an ethylenically unsaturated functional group and at least two hydrolyzable functional groups and the capped silicon has an average number of molecular weight of when minus approximately 5000 determined by nuclear magnetic resonance; and an effective photoinitiator for the radiation surface cure of the silicone composition, wherein the packaging material is surface curable by the radiation of the material to form the overlying cover layer and where after the formation of the same the material of Packaging under the cover layer is moisture curable. 18. A structural item of packaged element, comprising: an element for defining an encapsulation site that includes a boundary surface delimiting an encapsulation volume; an element arranged in the encapsulation volume; and a packaging means that encapsulates the element in the encapsulation volume, the packaging means comprising a liquid silicone medium covered by a solid silicone film enclosing and adhering adhesive. to the boundary surface, so that the element is packaged in the liquid silicone medium, and the liquid silicone medium is contained in the encapsulation volume by the solid silicone film. 19. A structural item of packaged item according to claim 18, wherein the element defining an encapsulation site comprises a housing that includes lateral boundary walls that provide the boundary wall surface. 20. A structural item of packaged element according to claim 18, wherein the packaged element comprises at least one member selected from the group consisting of electrical, mechanical, electronic, optical, acoustic, and material elements. 21. A structural item of packaged element according to claim 18, wherein the packaged element is an electromechanical element. 22. A structural item of packaged element according to claim 18, wherein the packaging means comprises a radiation-cured packaging composition formed by the radiation surface cure of a silicone composition comprising: a capped end silicone with ethylenically unsaturated functional group having an ethylenically unsaturated functional group and non-hydrolysable groups directly attached to a silicon atom thereof and the capped silicon having an average molecular weight number of at least about 5000 determined by nuclear magnetic resonance; and an effective photoinitiator .. for the euphemial healing by radiation of the silicone composition. wherein the packaging material is surface curable by the radiation of the material to form the superposed cover layer and where after the formation of the same the packaging material underlying the cover layer is not moisture curable. 23. A method of packaging an element in a structural encapsulation site that includes a boundary wall surface, the method comprising: arranging the element at the encapsulation site; applying to the encapsulation site a packaging composition of eilicone curable suporlioially by radiation, in liquid phase, which when exposed to radiation forms a solid surface layer covering uncured liquid of the composition, and which after healing The radiation surface thereof comprises internally uncured liquid by the solid surface layer formed by the radiation exposure, the silicone composition being surface-curable by radiation: an end-capped eylicon with an ethylenically unsaturated functional group which has at least two hydrolysable functional groups and the capped silicon has an average molecular weight number of at least about 5000 determined by nuclear magnetic resonance; and an effective photoinitiator-, for the superficial curing by radiation of the eilicone composition; and irradiating the silicone packaging composition at the encapsulation site, to superficially cure it and form a layer of eylicone eolide adhesively bonded and enveloping the boundary surface, and covering the packaging composition not cured by radiation. 24. A method according to claim 23, wherein the capped end silicone has no hydrolysable groups and the packaging composition not cured by radiation is incurable by exposure to moisture, and the packaging composition not cured by radiation is maintained. in an uncured state, so that the element on the encapsulation site is packaged in the packaging composition not cured by radiation. 25. A method according to claim 23, wherein the packaging compo sition not cured by radiation is a liquid. 26. A method according to claim 23, wherein the packaging composition not cured by radiation after the passage of radiation is curable by moisture, further comprising moisture curing the packaging composition not cured by radiation. 27. A silicone conformal coating composition curable by radiation and moisture which upon exposure to radiation is surface cured to form a firm, non-viscous surface coating that covers an uncured inner volume of the composition, the composition comprising the composition A first silicone fluid composed of a reaction product of a silanol-terminated silicone having at least 60 mole percent of Si-OH end groups and a viscosity, at room temperature, of 1000 centipoiees or less and a silane crosslinker which has an ethylenically unsaturated functional group curable by radiation, monovalent, and at least do hydrolysable groups; a second silicone fluid having both radiation curable (meth) acryl functional groups and moisture curable hydrolyzable groups; and an effective photoinitiator for the radiation cure of the silicone composition, wherein the molar ratio of the ethylenically unsaturated groups against the (meth) acryl functional groups is from 5:95 to 4: 6. 28. A composition according to claim 27, wherein the first and second eylicone fluids are prepared at the same time from an eilanone terminated by eilanol having at least 60 mole percent of Si-OH end groups and a viscosity, at room temperature, of 1000 centipoisee or less and at least two silane crosslinkers, one of the crosslinkers having an ethylenically unsaturated radiation curable group, monovalent, and at least two hydrolysable groups and the at least one other silane having a functional group ( met) acryl and at least two hydrolyzable groups. 29. A composition according to claim 27, wherein the molar ratio of the ethylenically unsaturated groups against the (meth) acryl functional groups is from 1: 5 to 35:65. 30. A composition according to claim 27, wherein the silicone terminated by silanol has a viscosity measured at room temperature of less than or equal to about 750 centipoise. 31. A composition according to claim 30, wherein the silanol-terminated silicone has a viscosity measured at ambient conditions of less than or equal to about 200. 32. A composition according to claim 27, further comprising an ethylene silicone. end capped per portion not reactive. 33. A composition according to claim 27, further comprising a moisture cure initiator. 34. A composition according to claim 27, wherein the monovalent ethylenically unsaturated functional group contains from 2 to 12 carbon atoms. 35. A composition according to claim 27, wherein the monovalent ethylenically unsaturated radical is selected from the group consisting of the vinyl, propenyl, and allyl groups. 36. A composition according to claim 27, wherein the monovalent ethylenically unsaturated radical is vinyl. 37. A composition according to claim 36, wherein the silane crosslinker is selected from the group consisting of vinyltrimethoxylaine, vinyltriaminosilane, vinyltriamidosilane, vinyltrioximino-silane, vinyltris (methylethylketoximino) silane, vinyltrisopro-penyloxysilane and vinyltriacetoxysilane. 38. A composition according to claim 27, wherein the (meth) acryl functional group is selected from the group consisting of acryl, (meth) acryl, butenyl, pentyl, hexenyl, octenyl, achenyloxy, alkenylamino, allyloxy, allylamino groups , furanyl, phenyl and benzyl. 39. A composition according to claim 27, wherein the second silicone fluid ee selects from the group consisting of silicone terminated by (meth) acryloxypropyl dimethoxysilyl, silicone terminated by acryloxypropyl dimethoxysilyl and a mixture thereof. 40. A composition according to claim 32, wherein the non-reactive portion capped silicone is selected from the group consisting of end silicone capped by alkyl, aryl, arylalkyl, and alkylaryls. 41. A composition according to claim 32, wherein the non-reactive portion capped silicone is trimethylsilyl capped end silicone. 42. A composition according to claim 27, wherein the photoinitiator is selected from the group consisting of benzoin, benzophenone, Michler's ketone, dialkoxy acetophenones, acetophenone, benzyl, and derivatives and mixtures thereof. 43. A composition according to claim 27, wherein the photoinitiator is diethoxyacetophenone. 44. A composition according to claim 27, wherein the photoinitiator has a concentration of from about 0.1 percent to about 15 weight percent, based on the weight of the silicone terminated by eilanol. 45. A composition according to claim 33, wherein the moisture cure initiator is an orthotitanate. 46. A composition according to claim 27, wherein the first silicone fluid is present in an amount of from about 20 to about 35 parts by weight, the second silicone fluid is present in an amount of from about 80 to about about 65 parts by weight, and the photoinitiator is present in an amount of from about 1 to about 15 parts by weight.