Radiation-curable adhesive tape

Abstract: There is provided a radiation-curable adhesive tape comprising a radiation-curable adhesive layer which is formed on a radiation transmitting-substrate. The radiation-curable adhesive layer is composed of an acrylic adhesive and radiation-curable compound having carbon-carbon double bonds. The radiation-curable tape can be used preferably in processing steps for the production of semiconductor wafer, ceramics and glass employing a direct picking-up system.

Description: The present invention relates to an adhesive tape that is used in a working step, wherein a semiconductor wafer (for example, consisting of Si and GaAs), ceramics, glass, etc. is cut or abraded. Hitherto, in semiconductor wafer dicing to make chips, a direct picking-up system has been used, wherein the semiconductor wafer is stuck and secured on an adhesive tape, the wafer is cut with a rotating circular blade along the chip shape, the securing adhesive tape is expanded radially to lower the adhesive force securing the chips a little, thereby enabling the chips to be picked up one by one from the adhesive tape, and immediately after that the chips are mounted on die. In the above system, when the semiconductor wafer is cut with a rotating circular blade, for the purpose of cooling the rotating circular blade and to eliminate the cuttings, washing water pressurized to approximately 2 kg/cm² is discharged against the rotating circular blade and the semiconductor wafer. Therefore, the chip-securing adhesive force in the dicing process is required to withstand the cutting impact force of the rotating circular blade and this water pressure, and in this sense, the greater the adhesive force the better. However, if the chip-securing adhesive force is excessive, the picking-up of the chips from the adhesive tape becomes difficult. That is, it is required that the chip-securing adhesive force for the dicing process and the chip-securing adhesive force for the picking-up are controlled in accordance with the size of the chip, and therefore the adhesive force of the adhesive tape must be set in accordance with the size of the chip. Further, in the case of chips having a size of 25 mm² or over, such as chips for recent LSI, whose integration degree has increased, the individual chip-securing adhesive force becomes high, so that a problem occurs in that the picking-up from the adhesive tape becomes difficult, not allowing direct picking-up to be applied. To overcome this problem, adhesive tapes for securing a semiconductor wafer have been suggested that comprise a support through which radiation, such as ultraviolet rays or ionizing radiation such as an electron beam, can pass, and an adhesive layer that is applied on the support and is cured when irradiated, the chip-securing adhesive force in the dicing process is made high, and after the semiconductor wafer is cut and separated into chips, the tape is irradiated from the support side with radiation to cure the radiation-curable adhesive layer, thereby lowering the chip-securing adhesive force considerably, so that chips, regardless of size, such as of size of 25 mm² or over, can be easily picked up. These suggestions provide semiconductor wafer-securing adhesive tapes having a radiation-transmitting support coated with a radiation-curable adhesive based on the principle that the radiation-curable compound in the adhesive is cured to cause the adhesive to have a three-dimensional structure so that the fluidity of the adhesive is greatly lowered, and as a result the chip-securing adhesive force is lowered remarkably. Examples of such adhesive tapes are those disclosed in Japanese Patent Application (OPI) Nos. 196956/1985, 201642/1985, 28572/1986, and 10180/1987. However, in the semiconductor wafer processing steps using a radiation-curable tape (e.g., sticking, cutting, grinding, polishing, radiation, and picking-up) such problems as described below may occur. However, the surface state of semiconductor wafers that will be stuck on semiconductor wafer-securing adhesive tapes are not always specular or almost specular. That is, usually the wafer surface is subjected to a grinding treatment, etching treatment, or special treatment wherein a metal such as gold is deposited, and this results in a number of fine crevices in the wafer surface. Consequently, fluidization of the adhesive cannot be fully prevented by simply causing the adhesive layer to have a three-dimensional network after irradiation, and therefore the chip-securing adhesive force changes conspicuously depending on the surface state of the wafer. As a result, in some cases the picking-up of even chips having a size of 25 mm² or below becomes difficult. Thus the change in the chip-securing adhesive force after irradiation due to the surface state of the chips where sticking will be effected leads to the problem that the picking-up workability lowers greatly lowering the productivity of the chips. Further, a film comprising a single resin layer, for example of polyvinyl chloride or ethylene-vinyl acetate copolymer is usually used as the substrate of a radiation-curable adhesive tape, but when it is desired to process the semiconductor wafer at a higher speed and more efficiently on an industrial production level, further problems mentioned below may arise. When a semiconductor wafer or the like is diced using a radiation-curable adhesive tape, considerable tension is exerted on the adhesive tape because the support film is under the influence of impact due to the cutting work by a rotating circular blade into the semiconductor wafer stuck on the adhesive tape, as well as being under the influence of the weight of the semiconductor wafer itself. Due to the tension, the support film is expanded, and sometimes the middle part of the adhesive tape may slacken and sink. When the thus-slackened adhesive tape is housed in a carrier cassette to be transported to the next step, such problems as the tape failing be housed or the wafer-to-wafer contact in the carrier cassette arise. Also, due to the slackening of the adhesive tape, the interval between the chips becomes narrow, and the adjacent ends of the chips touch, damaging the chips, which is another problem. Further, the radiation-curable adhesive tape will be subjected to irradiation to lower the chip-securing adhesive force as the pretreatment for picking up the chips. In the irradiation process the adhesive tape is heated by light in the infrared range that falls on the adhesive tape. As a result, further expansion or partial wrinkling of the adhesive tape is caused by the heat or the like. Since this expansion or wrinkling will be retained until the final step where the radiation-curable adhesive is cured and the chips are picked up, the expansion and wrinkling not only present the adhesive tape from being housed in a carrier cassette used for transportation between the steps, but also cause uneven intervals between the chips, leading to incomplete picking-up of the chips. On the other hand, in such a system wherein the adhesive force is lowered by providing a three-dimensional network to the adhesive by the curing reaction of a radiation-curable compound, the rubber-like properties of the adhesive tape retained during the dicing step almost disappear when the picking-up operation is performed. Therefore, such a problem will arise that the radial expansion of the adhesive tape that has hitherto been performed cannot be done. This expansion of the tape, which will be carried out or will not be carried out depending on the performance of the wafer processing apparatus or the size of the chips, is carried out to prevent the adjacent chips from touching and damaging the circuit surface when the chips are-picked up from the adhesive tape because the interval between the chip cut by the rotating circular blade is too small. As a method of obviating this problem, an adhesive tape is suggested that will be irradiated after the tape has been expanded, as disclosed in Japanese Patent Application (OPI) No. 59684/1987. In that case, as a resin having rubber-like properties, use is made of a resin such as polybutene, polyurethane, and 1,2-polybutadiene. Before irradiation these resins can be expanded to form an interval between the chips enough to prevent the chips from touching, but if it is tried to make the interval between the chips large enough as is required by a picking-up apparatus that recognizes an image when the chips are picked up, the intervals between the chips become ununiform due to necking of the film itself, and also the film is deteriorated due to the irradiation or due to expanding after the irradiation, resulting in a disappearance of the rubber-like properties, so that such enlargement of the interval becomes impossible. The adhesive of this adhesive tape is identical with that disclosed in Japanese Patent Application (OPI) No. 19695/1985, and the expansion of the adhesive tape is to be performed before the irradiation. Generally, when expansion is carried out after irradiation, since the expanded tape is heated by the heat of the irradiation, the case suffers from the disadvantage that the chips are not arranged uniformly (the aligning property becomes poor). Further, in such a method, apparatuses for picking up chips that have been conventionally used by semiconductor manufacturers cannot be suitably used. (Generally an expanding mechanism is incorporated in a picking-up apparatus, and irradiation is performed before the step of expanding the adhesive tape.) BRIEF SUMMARY OF THE INVENTION The main object of the present invention is to provide a radiation-curable adhesive tape that retains the advantages of conventional radiation-curable adhesive tapes and is free from the above problems. That is, the main object of the present invention is to provide a radiation-curable adhesive tape suitable for the processing steps of a semiconductor wafer and the like, employing a direct picking-up system. One of the objects of the present invention is to provide a radiation-curable adhesive tape wherein the advantages of conventional radiation curable adhesive are retained and the dependence of the chip-securing adhesive force on the surface state of a semiconductor wafer has been remarkably reduced for the later picking-up step. Another object of the present invention is to provide a radiation-curable adhesive tape that will neither be extended nor slackened when a semiconductor wafer is stuck on the adhesive tape and diced, and also will not be further extended or partially wrinkled when the adhesive tape is irradiated to lower the chip-securing adhesive force for the attainment of the picking-up system. Another object of the present invention is to provide a radiation-curable adhesive tape such that if the adhesive tape is extended or slackened by some external factors, the extended state or the slackened state of the adhesive tape is amended quickly by the heating action during irradiation and by cooling after irradiation. A still further object of the present invention is to provide a radiation-curable adhesive tape such that after being irradiated the adhesive tape is provided with rubber-like properties, the chip-securing adhesive force can be lowered, and the adhesive tape can be expanded for the attainment of the picking-up system. Other and further objects, features, and advantages of the invention will become apparent more fully from the following description. DETAILED DESCRIPTION OF THE INVENTION The term "adhesive tape" means a pressure-sensitive adhesive tape, and the term "adhesive" means a pressure-sensitive adhesive, in this specification and the claims. The inventors have studied many ways to overcome the defects of the prior radiation-curable adhesive tapes, and have found that when a certain radiation polymerizable cyanurate compound or isocyanurate compound is used in a prescribed proportion in an acrylic adhesive, the adhesive can be cured by irradiation to form a three-dimensional structure, and at the same time the cured adhesive is rendered flexible, and the chip-securing adhesive force can be caused to lower stably, independent of the roughness of the surface of the chips where the sticking is effected, all of which have led to the completion of the present invention. With respect to radially expandable adhesive tapes, although the inventors initially paid attention to, as support films for adhesive tapes, soft vinyl chloride film having rubber-like properties that can be expanded uniformly, it has been confirmed that such soft vinyl chloride resin film is deteriorated, for example, by ozone in the atmosphere that has been activated through irradiation, thereby allowing chlorine in the molecule to be set free readily, and there is residual adhesive on the chip that is considered to be brought about by chlorine gas entering the adhesive layer. A first embodiment of the invention concernes a radiation-curable, pressure-sensitive adhesive tape which comprises a radiation-transmitting multi-layer film comprising at least three radiation-transmitting resin layers, wherein a soft poly(vinyl chloride) or an elastomer is used as an intermediate layer, the radiation-transmitting film having a radiation-curable adhesive layer formed thereon which comprises 100 parts by weight of an acrylic adhesive and 5 to 500 parts by weight of at least one isocyanurate compound selected from the group consisting of: tris (acryloxyethyl) isocyanurate, tris (methacryloxyethyl)isocyanurate, tris-4-acryloxy-n-butylisocyanurate tris (1,3-diacryloxy-2-propyloxycarbonylamino-n-hexyl) isocyanurate, tris (1-acryloxy-3-methacryloxy-2-propyloxycarbonylamino-n-hexyl)isocyanurate, and bis (2-acryloxyethyl)-2-(5-acryloxy)hexyloxyethyl isocyanurate. Further, it is found that the chip-securing force is more stably lowered irrespective of the state of the surface of the chip, where the sticking is effected, by adding a silicone acrylate in a prescribed proportion into a radiation-curable acrylic adhesive. The acrylic adhesives used in the present invention comprise homopolymers whose major component is an ester of acrylic acid, or methacrylic acid, and copolymers of acrylic acid, or methacrylic acid, or its ester, or its acid amide with other copolymerizable monomers, and mixtures of these polymers. As the monomers and comonomers can be mentioned, for example, alkyl esters of acrylic acid or methacrylic acid, such as methyl esters, ethyl esters, butyl esters, 2-ethylhexyl esters, octyl esters, glycidyl esters, hydroxymethyl esters, 2-hydroxyethyl esters, and hydroxypropyl esters; and amides and N-substituted amides of acrylic acid and methacrylic acid, such as N-hydroxymethylacrylic acid amide, or methacrylic acid amide. If required, those can be used that contain a crosslinking agent, such as polyisocyanate compounds or alkyletherified melamine compounds. The acrylic adhesives per se are known and described, for example, in the Japanese Patent Applications referred to above. The content of the isocyanurate compound in the radiation-curable adhesive of the present invention is 5 to 500 parts by weight, preferably 60 to 150 parts by weight, for 100 parts by weight of the acrylic adhesive. If the content is too small, it is not preferable because the three-dimensional network of the radiation-curable adhesive that is formed by the irradiation becomes inadequate, it cannot prevent fluidization of the acrylic adhesive, and the chip-securing adhesive force cannot be lowered enough to allow the chips to be picked up easily. In contrast, if the content is too high, the plasticizing effect on the acrylic adhesive becomes too high, and the chip-securing adhesive force obtained will not be strong enough to withstand the cutting impact force by the rotating circular blade or the water pressure of the washing water in the dicing process. In the present invention a silicone (metha)acrylate (i.e., acrylate or methacrylate) is a silicone resin modified with a (metha)acrylate, and, for example, can be synthesized by a demethanolation reaction, wherein an organofunctional methoxysilane and a silanol-group-containing polysiloxane are condensed. If the functional number is expressed as the number of the (metha)acryl groups present in the molecular chain of the silicone (metha)acrylate, two or more functions are preferable, and particularly a silicone (metha)acrylate having four to six functions is preferable in the present invention. In the present invention the amount of such a silicone (metha)acrylate to be added is generally 0.01 to 20 parts by weight, preferably 0.1 to 10 parts by weight, and more preferably 0.5 to 4 parts by weight for 100 parts by weight of the acrylic adhesive. In the present invention the term "radiation" means light rays, such as ultraviolet rays or ionizing radiations such as an electron beam, and ultraviolet rays are used preferably. If the adhesive tape of the present invention is cured with ultraviolet ray irradiation, photopolymerization initiators can additionally be used, for example, isopropylbenzoin ether, isobutylbenzoin ether, benzophenone, Michler's ketone, chlorothioxanthone, dodecylthioxanthone, dimethylthioxanthone, diethylthioxanthone, benzyldimethylketal, α-hydroxycyclohexyl phenyl ketone, and 2-hydroxymethylphenylpropane. When one or more of these are added to the adhesive layer, if the curing reaction time is shortened or the amount of ultraviolet rays for irradiation is reduced, the curing reaction can be allowed to efficiently proceed to lower the chip-securing adhesive force. If necessary, the radiation-curable adhesive used in the present invention may contain, for example, a tackifier, a viscosity modifier, a surface-active agent, or other modifiers, and conventional components. As the support film of the radiation-curable adhesive tape of the present invention suitable for radial expansion, is made of at least three radiation-transmitting constitutional resin layers, with a soft PVC(poly (vinyl chloride)) resin or elastomer (rubber) used as the intermediate layer, and one that has that rubber-like properties that allow the film to be expanded uniformly. As soft polyvinyl chlorides used in the present invention are used typically those to which a phthalate, such as dibutyl phthalate, dioctyl phthalate, dinonyl phthalate, and diisodecyl phthalate; other polyester-type plasticizer; epoxy-type plasticizer, or trimellitate-type plasticizer has been added, but vinyl chloride-type copolymers such as urethane/vinyl chloride copolymers, ethylene/vinyl chloride copolymers, vinyl acetate/vinyl chloride copolymers, and ethylene/vinyl acetate/vinyl chloride copolymers, and mixtures of these, or mixtures of these with other resins or elastomers can also be used. These copolymers naturally include graft copolymers, and the above mixtures naturally include so-called alloys. As an elastomer (rubber), use can be made of common rubbers such as polyisoprene, and thermoplastic elastomers such as olefin-type thermoplastic elastomers. It is required to use, as a resin layer other than the soft polyvinyl chloride resin or thermoplastic elastomer of the intermediate layer in the support film, one that does not deteriorate the rubber-like properties of the support film, allows the transmission of radiation, and is flexible. Polymers that can be used as such a resin include homopolymers or copolymers of α-olefins, such as polyethylenes, ethylene/propylene copolymers, polypropylenes, ethylene/vinyl acetate copolymers, polybutene, polymethylpentenes, ethylene/ethyl acrylate copolymers, ethylene/methyl acrylate copolymers, and ethylene/acrylic acid copolymers, and ionomers, and mixtures thereof. Preferred are a high density polyethylene or polypropylene layer having a Vicat softening point of 120°C or more. Herein the term "rubber-like properties" of the support film means properties such that, in the tensile strength and elongation measurement (JIS-Z0237), the ratio of 50% modulus (20°C) to 25% modulus (20°C) is at least 1.2, preferably 1.5 or over, and 25% modulus (20°C) is 60 kg/cm² or below. The thickness of the support film is preferably 30 to 300 µm in view of the transmission of radiation. Of these, the thickness of the intermediate layer of soft PVC resins or thermoplastic elastomers is 25 to 290 µm, which is set arbitrarily in accordance with required properties. In the present invention, although there is no particular limit on the thickness of the radiation-curable adhesive layer, the thickness is generally 2 to 50 µm. Generally, the radiation-curable adhesive tape of the present invention has a separator film on the radiation-curable adhesive layer. Therefore, in many cases the state of the radiation-curable adhesive tape of the present invention before it is used has such a constitution that it has three layers, that is, a substrate, an adhesive layer, and a separator. The separator is made, for example, of polyolefin film, such as polypropylene film or the like, or polyethylene terephthalate film. It is a matter of course that the separator is removed when the radiation-curable adhesive tape is used. A second embodiment of the invention concerns a radiation-curable, pressure-sensitive adhesive tape, which tape comprises a radiation transmitting substrate having a ratio of 50% modulus (20° C) to 25% modulus (20° C) of at least 1.2 with the 25% modulus (20° C) being 60 kg/cm² or less, and which tape comprises a radiation transmitting substrate comprising at least two kinds of resin layers and being composed of a multi-layer film having at least three layers including an intermediate layer having rubber-like properties and being selected from a soft poly(vinyl chloride) or an elastomer, and a radiation-curable adhesive layer comprising an acrylic adhesive formed on one side of the substrate containing 5 to 500 parts by weight of an isocyanurate compound per 100 parts by weight of the acrylic adhesive; the isocyanurate compound being selected from the group consisting of: tris (acryloxyethyl)isocyanurate, tris (methacryloxyethyl)isocyanurate, tris-4-acryloxy-n-butylisocyanurate, tris (1,3-diacryloxy-2-propyloxycarbonylamine-n-hexyl) isocyanurate, tris (1-acryloxy-3-methacryloxy-2-propyloxycarbonylamino-n-hexyl)isocyanurate and bis (2-acryloxyethyl)-2-(5-acyrloxy)hexyloxyethyl-isocyanurate. As regards the acrylic adhesives used in the present invention reference is made to the foregoing description. The content of the isocyanurate compound in the radiation-curable adhesive of the present invention is 5 to 500 parts by weight, preferably 60 to 150 parts by weight, for 100 parts by weight of the acrylic adhesive. Again, in the present invention a silicone (metha)acrylate (i.e., acrylate or methacrylate) is a silicone resin modified with a (metha)acrylate, and, for example, can be synthesized by a demethanolation reaction, wherein an organofunctional methoxysilane and a silanol-group-containing polysiloxane are condensed. If the functional number is expressed as the number of the (metha)acryl groups present in the molecular chain of the silicone (metha)acrylate, two or more functions are preferable, and particularly a silicone (metha)acrylate having four to six functions is preferable in the present invention. In the present invention the amount of such a silicone (metha)acrylate to be added is generally 0.01 to 20 parts by weight, preferably 0.1 to 10 parts by weight, and more preferably 0.5 to 4 parts by weight for 100 parts by weight of the acrylic adhesive. Again in the present invention the term "radiation" means light rays, such as ultraviolet rays or ionizing radiations such as an electron beam, and ultraviolet rays are used preferably. Again, if the adhesive tape of the present invention is cured with ultraviolet ray irradiation, photopolymerization initiators can additionally be used. Again, if necessary, the radiation-curable adhesive used in the present invention may contain, for example, a tackifier, a viscosity modifier, a surface-active agent, or other modifiers, and conventional components. Again, as the support film of the radiation-curable adhesive tape of the present invention suitable for radial expansion, preferable use is made of one that is made of at least three radiation-transmitting constitutional resin layers, with a soft PVC(poly (vinyl chloride)) resin or elastomer (rubber) used as the intermediate layer, and one that has that rubber-like properties that allow the film to be expanded uniformly. As regards soft polyvinyl chlorides and elastomers (rubbers) used in the present invention reference can be made to the foregoing description. It is required to use, as a resin layer other than the soft polyvinyl chloride resin or thermoplastic elastomer of the intermediate layer in the support film, one that does not deteriorate the rubber-like properties of the support film, allows the transmission of radiation, and is flexible. Polymers that can be used as such a resin include homopolymers or copolymers of α-olefins, such as polyethylenes, ethylene/propylene copolymers, polypropylenes, ethylene/vinyl acetate copolymers, polybutene, polymethylpentenes, ethylene/ethyl acrylate copolymers, ethylene/methyl acrylate copolymers, and ethylene/acrylic acid copolymers, and ionomers, and mixtures thereof. Preferred are a high density polyethylene or polypropylene layer having a Vicat softening point of 120°C or more. Herein the term "rubber-like properties" of the support film means properties according to JIS-Z0237. In the tensile strength and elongation measurement the ratio of 50% modulus (20°C) to 25% modulus (20°C) is preferably 1.5 or over. As regards the thickness of the support film, the thickness of the radiation-curable adhesive layer and a separator film on the radiation-curable adhesive layer reference can be made to the foregoing description. A third embodiment of the invention concerns a radiation-curable, pressure-sensitive adhesive tape which comprises a multi-layer radiation-transmitting substrate comprising at least three radiation-transmitting resin layers with at least one member selected from a soft poly(vinyl chloride) or an elastomer used as an intermediate layer; the substrate having a radiation-curable adhesive layer formed thereon which comprises: 100 parts by weight of an acrylic adhesive; 5 to 500 parts by weight of at least one isocyanurate compound selected from the group consisting of: tris (acryloxyethyl) isocyanurate, tris (methacryloxyethyl) isocyanurate, tris-4-acryloxy-n-butylisocyanurate, tris (1,3-diacryloxy-2-propyloxycarbonylamino-n-hexyl) isocyanurate, tris (1-acryloxy-3-methacryloxy-2-propyloxycarbonylamino-n-hexyl) isocyanurate, and bis (2-acryloxyethyl)-2-(5-acryloxy)hexyloxyethyl isocyanurate; and 0.5 to 100 parts by weight of a urethane acrylate compound having carbon-carbon double bonds, per 100 parts by weight of the acrylic adhesive. As regards adding a silicone acrylate into a radiation-curable acrylic adhesive, reference is made to the foregoing description. A further excellent tape can be obtained when, as the composition of the adhesive, the composition mentioned below is used. That is, it has been found that when, as the radiation-curable adhesive layer to be applied on one surface of the support film, an urethane acrylate compound that includes carbon-carbon double bonds in a prescribed proportion in an acrylic adhesive, and an adhesive consisting of a cyanurate or isocyanurate compound that will have rubber-like properties as physical properties after irradiation are used, the radiation-curable adhesive layer can be cured through irradiation, thereby forming a three-dimensional network, and that at the same time flexibility can be provided, and a stable effect of the chip-securing adhesive force can be exhibited irrespective, for example, of the surface roughness of the chips, and the present invention has been completed on the basis of this finding. Thus, according to one of the preferable embodiments of the present invention, there is provided a radiation-curable adhesive tape that comprises a support film made up of at least three radiation-transmitting constitutional resin layers, with the intermediate layer being a soft vinyl chloride resin or elastomer (rubber), and a radiation-curable adhesive layer formed on one surface of said support film containing an urethane acrylate compound. As regards the acrylic adhesives used in the present invention reference is made to the foregoing description, The content of the isocyanurate compound in the radiation-curable adhesive of the present invention is 5 to 500 parts by weight, preferably 60 to 150 parts by weight, for 100 parts by weight of the acrylic adhesive. The urethane acrylate compound used in the radiation-curable adhesive of the present invention is a compound that contains two carbon-carbon double bonds polymerizable by irradiation, has rubber-like properties as physical properties after curing by irradiation, and is a urethane acrylate-type compound having a linear aliphatic molecular structure, such as polyesters or polyols having a urethane bond in the molecule, which may be in the form of a monomer or an oligomer. Such a compound can be synthesized by using, as raw material, for example, methacrylic acid, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrytate, or polyethylene glycol acrylate, and a polyvalent isocyanate compound such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, and diphenylmethane-4,4-diisocyanate. Herein the term "rubber-like properties" of the urethane acrylate-type compounds after curing by irradiation means properties such that, in the tensile strength and elongation measurement (JIS-K7113), the tensile strength at break is 100 kg/cm² or below, preferably 50 kg/cm² or below, and the tensile elongation at break is at least 50%. The content of the urethane-type acrylate compound in the radiation-curable adhesive of the present invention is preferably 10 to 100 parts by weight, for 100 parts by weight of the acrylic adhesive. The inclusion of the urethane-type acrylate compound affects the flexibility of the three-dimensional network of the radiation-curable adhesive formed by irradiation preventing the plasticizing effect on the acrylic adhesive. As regards the term "radiation" reference is made to the foregoing description. Again, if the adhesive tape of the present invention is cured with ultraviolet ray irradiation, photopolymerization initiators can additionally be used, Again, if necessary, the radiation-curable adhesive used in the present invention may contain, for example, a tackifier, a viscosity modifier, a surface-active agent, or other modifiers, and conventional components. Again as the support film of the radiation-curable adhesive tape of the present invention suitable for radial expansion, preferable use is made of one that is made of at least three radiation-transmitting constitutional resin layers, with a soft PVC(poly (vinyl chloride)) resin or elastomer (rubber) used as the intermediate layer, and one that has that rubber-like properties that allow the film to be expanded uniformly. As regards soft polyvinyl chlorides and elastomers (rubbers) used in the present invention reference can be made to the foregoing description. It is required to use, as a resin layer other than the soft polyvinyl chloride resin or thermoplastic elastomer in the support film, one that does not deteriorate the rubber-like properties of the support film, allows the transmission of radiation, and is flexible. Reference is made to the foregoing description. As regards the term "rubber-like properties" of the support film, the thickness of the support film, the thickness of the radiation-curable adhesive layer, and a separator film on the radiation-curable adhesive layer reference can be made to the foregoing description. A fourth embodiment of the invention concerns a radiation-curable, pressure-sensitive adhesive tape which comprises a radiation-transmitting substrate having a radiation-curable adhesive layer formed thereon which comprises: 100 parts by weight of an acrylic adhesive; 5 to 500 parts by weight of at least one cyanurate and/or isocyanurate compound selected from the group consisting of: tris (acryloxyethyl) isocyanurate, tris (methacryloxyethyl) isocyanurate, tris-4-acryloxy-n-butylisocuanurate, tris (1,3-diacryloxy-2-propyloxycarbonylamino-n-hexyl) isocyanurate tris (1-acryloxy-3-methacryloxy-2-propyloxycarbonylamino-n-hexyl) isocyanurate, and bis (2-acryloxyethyl)-2-(5-acryloxy)hexyloxyethyl isocyanurate; 0.5 to 100 parts by weight of a urethane acrylate compound having carbon-carbon double bonds, per 100 parts by weight of the acrylic adhesive; and 0.01 to 20 parts by weight of a silicone acrylate compound, per 100 parts by weight of the acrylic adhesive. As regards adding a silicone acrylate into a radiation-curable acrylic adhesive, reference is made to the foregoing description. Further it is found that an adhesive tape having more excellent properties can be provided by using, as the film substrate, a multilayer film having two or more different constitutional layers, leading to the present invention. Thus, according to one of the preferable embodiments of the present invention, there is provided a radiation-curable adhesive tape that comprises a radiation-curable adhesive layer that is formed on a radiation transmitting substrate consisting of a multi-layer film having at least two different constitutional layers, and which contains 100 parts by weight of an acrylic adhesive and 5 to 500 parts by weight of a compound having a carbon-carbon double bond. The inventors also have variously studied to obtain such adhesive tapes that when a wafer is stuck on the adhesive tape and dicing is carried out, the tape will not be extended or slackened, or even if the tape is extended or slackened, the extended state or the slackened state is canceled after irradiation. As a result, it has been found that when the support film of the radiation-curable adhesive tape consists of at least two types of resins, and as at least one of the resins, use is made of a high-density polyethylene, preferably or polypropylene, even a non-oriented film can be shrunk favorably by irradiation, and the extended or slackened state formed by tension or the like exerted on the adhesive tape can be canceled well. Thus, according to one of the preferable embodiments of the present invention, there is provided a radiation-curable adhesive tape that includes, as the radiation-transmitting support film, at least two different resin layers, and a radiation-curable adhesive layer provided on one surface of the support film, with at least one of the layers constituting the support film being a high-density polyethylene resin layer or polypropylene resin layer. With respect to radially expandable adhesive tapes, although the inventors initially paid attention to, as support films for adhesive tapes, soft vinyl chloride film having rubber-like properties that can be expanded uniformly, it has been confirmed that such soft vinyl chloride resin film is deteriorated, for example, by ozone in the atmosphere that has been activated through irradiation, thereby allowing chlorine in the molecule to be set free readily, and there is residual adhesive on the chip that is considered to be brought about by chlorine gas entering the adhesive layer. Various studies have been made to overcome these defects, and as a result it has been found that when a film consisting of three-different radiation transmitting constitutional resin layers, with the intermediate layer being soft vinyl chloride resin (hereinafter referred to as PVC resin) or elastomer (rubber), is used as a support film of a radiation-curable adhesive tape, the intervals between the chips cut and separated by a rotating circular blade can be spread uniformly, and the intervals between the chips required for a picking-up apparatus that recognizes an image when the chips are picked up can be increased considerably. Since the composition of the adhesive comprises an urethane acrylate compound as the composition mentioned before does, a further excellent tape can be obtained As regards the acrylic adhesives used in the present invention reference is made to the foregoing description Cyanurate compounds used in the radiation-curable adhesive of the present invention are compounds that have a triazine ring or isotriazine ring in the molecule, contain radiation-polymerizable carbon-carbon double bonds, and they may be in the form of a monomer, oligomer, or a mixture thereof. Compounds having a triazine ring or an isotriazine ring can generally be synthesized by the usual cyclization reaction using, as raw material, halocyan compounds, dianiline compounds, diisocyanates compounds, and the like. Further, a radiation-curable carbon-carbon double bond-containing group, for example, a functional group containing a vinyl group, an allyl group, an acryloxy group, or a methacryloxy group is introduced into the thus-synthesized compound to give a compound that will be used in the present invention. In the present invention, one containing an acryloxy group or methacryloxy group is preferably used. In the present invention, although beside the above-mentioned point there is no particular limitation on the cyanurate compounds, it is preferable that the carbon-carbon double bond introduced into the triazine ring or isotriazine ring does not have a so-called rigid molecular structure, that is, does not contain, for example, an aromatic group or a heterocyclic group. This is because the adhesive of the present invention becomes excessively brittle if the radiation polymerizable compound is made excessively rigid by the introduction of a carbon-carbon double bond-containing group. Therefore, it is preferable that the linking group between the carbon-carbon double bond and the triazine ring or isotriazine ring is a group wherein the atoms can rotate freely. Examples of such a group are aliphatic groups such as alkylene groups and alkylidene groups, which may have a -O-, -OCO-, -COO-, -NHCO- or -NHCOO-bond. If the carbon-carbon double bond is linked to the triazine ring or isotriazine ring via -O-, it is desirable that the number of carbon atoms between carbon of the double bond and the oxygen is two or more. Examples of the cyanurate compounds include 2-propenyl di-3-butenylcyanurate. Generally the number of radiation polymerizable carbon-carbon double bonds per monomer of the said cyanurate compound used in the present invention or per repeating unit of the oligomer thereof is preferably at least 2, and more preferably 2 to 6. If the number of the double bonds is less than 2, a degree of crosslinking enough to lower the adhesive strength by irradiation cannot be obtained, while if the number exceeds 6, sometimes the brittleness of the adhesive after the radiation cure becomes excessive. The content of the cyanurate compound or isocyanurate compound in the radiation-curable adhesive of the present invention is 5 to 500 parts by weight, preferably 60 to 150 parts by weight, for 100 parts by weight of the acrylic adhesive. As regards the urethane acrylate compound used in the radiation-curable adhesive of the present invention reference can be made to the foregoing description, Herein the term "rubber-like properties" of the urethane acrylate-type compounds after curing by irradiation means properties such that, in the tensile strength and elongation measurement (JIS-K7113), the tensile strength at break is 100 kg/cm² or below, preferably 50 kg/cm² or below, and the tensile elongation at break is at least 50%. The content of the urethane-type acrylate compound in the radiation-curable adhesive of the present invention is preferably 10 to 100 parts by weight, for 100 parts by weight of the acrylic adhesive. The inclusion of the urethane-type acrylate compound affects the flexibility of the three-dimensional network of the radiation-curable adhesive formed by irradiation preventing the plasticizing effect on the acrylic adhesive. As regards the term "radiation" reference is made to the foregoing description, Again, if the adhesive tape of the present invention is cured with ultraviolet ray irradiation, photopolymerization initiators can additionally be used. Again, if necessary, the radiation-curable adhesive used in the present invention may contain, for example, a tackifier, a viscosity modifier, a surface-active agent, or other modifiers, and conventional components. For the radiation transmitting substrate used in the present invention, plastic or elastmer ("Resin" or "polymer" is given in this specification and claims as a general term to these) is preferably used, and there is no particular limit on the material as long as it can transmit radiation. If the radiation-curable adhesive is cured by irradiation with ultraviolet rays, it is required to use, as a substrate for it, one good in light transmission. Examples of polymers used for such a substrate include homopolymers or copolymers of α-olefins such as polyethylenes, polypropylenes, ethylene/propylene copolymers, polybutene-1, poly-4-methylpentene-1, ethylene/vinyl acetate copolymers, ethylene/ethyl acrylate copolymers, ethylene/methyl acrylate copolymers, ethylene/acrylic acid copolymers, and ionomers, or mixtures thereof; vinyl chloride-type homopolymers, or copolymers such as polyvinyl chloride, vinyl chloride/ethylene copolymers, vinyl chloride/vinyl acetate copolymers, and vinyl chloride/ethylene/vinyl acetate copolymers; fluorine-type polymers, such as vinyl fluoride/ethylene copolymers, vinylidene fluoride/ethylene copolymers, and FEP(fluorinated ethylene propylene); and engineering plastics, such as polyethylene terephthalate, polycarbonate, and polymethyl methacrylate. The substrate is generally in the form of a sheet or film (referred to as film in this specification and claims), and it is desirable that the thickness of the substrate is generally on the order of 10 to 1000 µm. Although there is no particular limit on the thickness of the radiation-curable adhesive layer on the substrate, the thickness of the radiation-curable adhesive layer is generally 2 to 50 µm. In the present invention, when a multilayer film is used, the constitutional layers have different properties from each other. At least one of them is a constitutional layer acting mainly to provide required mechanical properties (e.g., rigidity, strength, extensibility and softness), and at least one other layer is a constitutional layer acting mainly to give a firm adhesion with the adhesive. As the radiation-transmitting substrate used in the present invention, preferably use can be made, for example, of plastics and elastomers, and there is no particular limit on the substrate material as long as it can transmit radiation. In the present invention, at least one of the layers constituting the multilayer film is used to provide mechanical properties, as mentioned before, and examples of polymers that can be used for such a constitutional layer include such polymers as enumerated above for radiation-transmitting substrate. The thickness of the said constitutional layer is generally 10 to 500 µm, and preferably 30 to 300 µm. In this invention, one other layer constituting the multilayer film is used mainly to give firm adhesion with the adhesive, as mentioned before, and the polymer that constitutes said layer is a so-called adhesive polymer, specifically a copolymer of an α-olefin. Specific examples thereof include ethylene/vinyl acetate copolymers, ethylene/ethyl acrylate copolymers, ethylene/methyl acrylate copolymers, ethylene/acrylic acid copolymers, and ionomers. The thickness of said adhesive layer is preferably 2 to 50 µm. The adhesive layer surface is, in some cases, modified, for example, by a corona treatment or anchoring treatment to make the adhesion of the adhesive layer surface firm to the adhesive. Examples of constitutions of the multi-layer film used as a substrate in the present invention include one with a layer to provide mechanical properties (referred to as layer A), on which a layer for providing adhesion with the adhesive (referred to as layer B) is laminated; a constitution having layer A and layers B, with layer A sandwiched between the layers B; and a constitution wherein two or more layers A and two or more layers B are alternatively laminated. In these constitutions, in order to increase the adhesion between-the layer A and B layer, in some cases, a bonding agent is interposed between them. The high-density polyethylene used in the present invention is one obtained by the known polyethylene polymerization method, and also includes those represented by moderate pressure and low pressure polyethylenes. Preferably, high-density polyethylenes or polypropylenes having a Vicat softening point of at least 120°C are used. Generally, the suitable thickness of such a support film is 30 to 300 µm in view of the strength/elongation properties and radiation-transmitting properties. The thickness of the resin layer made of high-density polyethylenes or polypropylenes is arbitrarily set in accordance with the required properties for the support film, and is generally in the range of 3 to 90% of the total thickness of the support film. As the support film of the radiation-curable-adhesive tape of the present invention suitable for radial expansion, preferable use is made of one that is made of at least three radiation-transmitting constitutional resin layers, with a soft PVC(poly (vinyl chloride)) resin or elastomer (rubber) used as the intermediate layer, and one that has that rubber-like properties that allow the film to be expanded uniformly. As regards soft polyvinyl chlorides and elastomers (rubbers) used in the present invention reference can be made to the foregoing description, As regards the term "rubber-like properties" of the support film, the thickness of the support film, the thickness of the radiation-curable adhesive layer and a separator film on the radiation-curable adhesive layer reference can be made to the foregoing description. A fifth embodiment of the invention concerns a radiation-curable, pressure-sensitive adhesive tape which comprises a radiation-curable adhesive layer that is formed on a radiation-transmitting substrate and that contains 100 parts by weight of an acrylic adhesive, 5 to 500 parts by weight of cyanurate compounds, isocyanurate compounds, polyacrylates of aliphatic polyols and/or polymethacrylates of aliphatic polyols and 0.01 to 20 parts by weight of a silicone acrylate compound. As regards adding a silicone acrylate into a radiation-curable acrylic adhesive, reference is made to the foregoing description, Again, Further it is found that an adhesive tape having more excellent properties can be provided by using, as the film substrate, a multilayer film having two or more different constitutional layers, leading to the present invention. Reference is made to the foregoing description. Again, a further excellent tape can be obtained if the composition of the adhesive comprises an urethane acrylate compound as described before. As regards the acrylic adhesives used in the present invention reference can be made to the foregoing description, Cyanurate compounds or isocyanurate compounds used in the radiation-curable adhesive of the present invention are compounds that have a triazine ring or isotriazine ring in the molecule, contain radiation-polymerizable carbon-carbon double bonds, and they may be in the form of a monomer, oligomer, or a mixture thereof. Compounds having a triazine ring or an isotriazine ring can generally be synthesized by the usual cyclization reaction using, as raw material, halocyan compounds, dianiline compounds, diisocyanates compounds, and the like. Further, a radiation-curable carbon-carbon double bond-containing group, for example, a functional group containing a vinyl group, an allyl group, an acryloxy group, or a methacryloxy group is introduced into the thus-synthesized compound to give a compound that will be used in the present invention. In the present invention, one containing an acryloxy group or methacryloxy group is preferably used. In the present invention, although beside the above-mentioned point there is no particular limitation on the cyanurate or isocyanurate compounds, it is preferable that the carbon-carbon double bond introduced into the triazine ring or isotriazine ring does not have a so-called rigid molecular structure, that is, does not contain, for example, an aromatic group or a heterocyclic group. This is because the adhesive of the present invention becomes excessively brittle if the radiation polymerizable compound is made excessively rigid by the introduction of a carbon-carbon double bond-containing group. Therefore, it is preferable that the linking group between the carbon-carbon double bond and the triazine ring or isotriazine ring is a group wherein the atoms can rotate freely. Examples of such a group are aliphatic groups such as alkylene groups and alkylidene groups, which may have a -O-, -OCO-, -COO-, -NHCO- or -NHCOO-bond. If the carbon-carbon double bond is linked to the triazine ring or isotriazine ring via -O-, it is desirable that the number of carbon atoms between carbon of the double bond and the oxygen is two or more. Examples of the cyanurate or isocyanurate compounds include 2-propenyl di-3-butenylcyanurate, 2-hydroxyethyl bis(2-acryloxyethyl) isocyanurate, tris-4-acryloxy-n-butylisocyanurate tris(acryloxyethyl) isocyanurate, tris(methacryloxyethyl) isocyanurate, bis(2-acryloxyethyl) 2-(5-acryloxy)-hexyloxyethyl isocyanurate, tris(1,3-diacryloxy-2-propyl-oxycarbonylamino-n-hexyl) isocyanurate, and tris(1-acryloxy-3-methacryloxy-2-propyl-oxycarbonylamino-n-hexyl) isocyanurate. Generally the number of radiation polymerizable carbon-carbon double bonds per monomer of the said cyanurate compound or isocyanurate compound used in the present invention or per repeating unit of the oligomer thereof is preferably at least 2, and more preferably 2 to 6. If the number of the double bonds is less than 2, a degree of crosslinking enough to lower the adhesive strength by irradiation cannot be obtained, while if the number exceeds 6, sometimes the brittleness of the adhesive after the radiation cure becomes excessive. The content of the cyanurate compound or isocyanurate compound in the radiation-curable adhesive of the present invention is preferably 60 to 150 parts by weight, for 100 parts by weight of the acrylic adhesive. Compounds having carbon-carbon double bonds as the curable adhesive of the present invention include, in addition to the above cyanurate or isocyanurate compounds, such other radiation-curable compounds as polyacrylates or polymethacrylates of aliphatic polyols. Examples of these compounds are acrylates or methacrylates of ethylene glycol, diethylene glycol, trimethylolpropane, 1,4-butanediol, 1,6-hexanediol, pentaerythritol, dipentaerythritol, and polyethylene glycols (having 3 to 14 carbon atoms), and their oligomers. These compounds can be used together with a cyanurate compound or isocyanurate compound having carbon-carbon double bonds, even when the latter is needed. In the present invention the amount of the silicone (metha)acrylate to be added is preferably 0.5 to 4 parts by weight for 100 parts by weight of the acrylic adhesive. As regards the term "radiation" reference is made to the foregoing description, are used preferably. Again, if the adhesive tape of the present invention is cured with ultraviolet ray irradiation, photopolymerization initiators can additionally be used, Again, if necessary, the radiation-curable adhesive used in the present invention may contain, for example, a tackifier, a viscosity modifier, a surface-active agent, or other modifiers, and conventional components. As regards the radiation transmitting substrate reference can be made to the foregoing description. The thickness of said adhesive layer is preferably 2 to 50 µm. The adhesive layer surface is, in some cases, modified, for example, by a corona treatment or anchoring treatment to make the adhesion of the adhesive layer surface firm to the adhesive. With reference to the foregoing description the support film of the radiation-curable adhesive tape of the present invention is again preferably made of at least three radiation-transmitting constitutional resin layers, with a soft PVC(poly (vinyl chloride)) resin or elastomer (rubber) used as the intermediate layer, and one that has that rubber-like properties that allow the film to be expanded uniformly. Further, as regards the term "rubber-like properties" of the support film, the thickness of the support film, and the thickness of the radiation-curable adhesive layer reference can be made to the foregoing description. Generally, the radiation-curable adhesive tape of the present invention has a separator film on the radiation-curable adhesive layer. Reference can be made to the foregoing description. When the radiation-curable adhesive tape of the present invention is used, for example, it exhibits such an excellent effect that the tape has a chip-securing adhesive force adequate to secure the severed chips when the semiconductor wafer is cut into chips (that is, when the dicing process is carried out), and since the adhesive layer takes a three-dimensional structure and is flexible after irradiation, a stable low adhesive force can be obtained irrespective of the surface property of the semiconductor wafer, and the severed chips can be picked up from the securing tape easily at all times. Further, the present invention exhibits such an excellent effect that, after the wafer is cut into chips, the adhesive tape is radially expanded, since the intervals between the chips can be spread uniformly, the chips can be picked up easily without being damaged. Thus, by use of the adhesive tape the processing including picking-up system can be conducted without any problems. The above advantages can also be applied to the processing of ceramics glass, etc.

Claims: A radiation-curable, pressure-sensitive adhesive tape which comprises a radiation-transmitting multi-layer film comprising at least three radiation-transmitting resin layers, wherein a soft poly(vinyl chloride) or an elastomer is used as an intermediate layer, the radiation-transmitting film having a radiation-curable adhesive layer formed thereon which comprises 100 parts by weight of an acrylic adhesive and 5 to 500 parts by weight of at least one isocyanurate compound selected from the group consisting of: tris (acryloxyethyl) isocyanurate, tris (methacryloxyethyl)isocyanurate, tris-4-acryloxy-n-butylisocyanurate tris (1,3-diacryloxy-2-propyloxycarbonylamino-n-hexyl) isocyanurate, tris (1-acryloxy-3-methacryloxy-2-propyloxycarbonylamino-n-hexyl)isocyanurate, and bis (2-acryloxyethyl)-2-(5-acryloxy)hexyloxyethyl isocyanurate. The radiation-curable, pressure-sensitive adhesive tape as claimed in claim 1, wherein the radiation-transmitting multi-layer film comprises at least one layer of polyethylene. The radiation-curable, pressure-sensitive adhesive tape as claimed in claim 1, wherein the radiation-transmitting multi-layer film comprises at least one high density polyethylene or polypropylene layer having a vicat softening point of 120° C or over. The radiation-curable, pressure-sensitive adhesive tape as claimed in claim 1, wherein the radiation-curable adhesive layer further comprises 0.01 to 20 parts by weight of silicone acrylate compound for 100 parts by weight of acrylic adhesive. The radiation-curable, pressure-sensitive adhesive tape as claimed in claim 1, wherein the radiation-curable adhesive layer comprises 60 to 150 parts by weight of isocyanurate compounds for 100 parts by weight of acrylic adhesive. The radiation-curable, pressure-sensitive adhesive tape as claimed in claim 1, wherein the radiation-curable adhesive layer further comprises 0.5 to 4 parts by weight of silicone acrylate compound for 100 parts by weight of acrylic adhesive. A radiation-curable, pressure-sensitive adhesive tape, which tape comprises a radiation transmitting substrate having a ratio of 50% modulus (20° C) to 25% modulus (20° C) of at least 1.2 with the 25% modulus (20° C) being 60 kg/cm² or less, and which tape comprises a radiation transmitting substrate comprising at least two kinds of resin layers and being composed of a multi-layer film having at least three layers including an intermediate layer having rubber-like properties and being selected from a soft poly(vinyl chloride) or an elastomer, and a radiation-curable adhesive layer comprising an acrylic adhesive formed on one side of the substrate containing 5 to 500 parts by weight of an isocyanurate compound per 100 parts by weight of the acrylic adhesive; the isocyanurate compound being selected from the group consisting of: tris (acryloxyethyl)isocyanurate, tris (methacryloxyethyl)isocyanurate, tris-4-acryloxy-n-butyl isocyanurate, tris (1,3-diacryloxy-2-propyloxycarbonylamino-n-hexyl) isocyanurate, tris (1-acryloxy-3-methacryloxy-2-propyloxycarbonylamino-n-hexyl)isocyanurate and bis (2-acryloxyethyl)-2-(5-acryloxy)hexyloxyethyl-isocyanurate. The radiation-curable, pressure-sensitive adhesive tape as claimed in claim 7, wherein an outer layer of the multi-layer film is composed of a resin selected from polyethylene, ethylene/propylene copolymer, polypropylene, ethylene/vinyl acetate copolymer, polymethylpentene, ethylene/ethyl acrylate copolymer, ethylene/methyl acrylate copolymer, and ethylene/acrylic acid copolymer. The radiation-curable, pressure-sensitive adhesive tape as claimed in claim 7, wherein an outer layer of the multi-layer film is composed of a ethylene/vinyl acetate copolymer. The radiation-curable, pressure-sensitive adhesive tape as claimed in claim 7, wherein the tape is for expansion use. The radiation-curable, pressure-sensitive adhesive tape as claimed in claim 7, wherein the radiation-curable adhesive layer further comprises 0.01 to 20 parts by weight of a silicone acrylate compound for 100 parts by weight of acrylic adhesive. The radiation-curable, pressure-sensitive adhesive tape as claimed in claim 7, wherein the radiation-curable adhesive layer comprises 60 to 150 parts by weight of isocyanurate compounds for 100 parts by weight of acrylic adhesive. The radiation-curable, pressure-sensitive adhesive tape as claimed in claim 7, wherein the radiation-curable adhesive layer further comprises 0.5 to 4 parts by weight of silicone acrylate compound for 100 parts by weight of acrylic adhesive. The radiation-curable, pressure-sensitive adhesive tape as claimed in claim 7, which further comprises a separator film on the radiation-curable adhesive layer. The radiation-curable, pressure-sensitive adhesive tape as claimed in claim 7, wherein the tape is radiation-curable with ultraviolet ray. A radiation-curable, pressure-sensitive adhesive tape which comprises a multi-layer radiation-transmitting substrate comprising at least three radiation-transmitting resin layers with at least one member selected from a soft poly(vinyl chloride) or an elastomer used as an intermediate layer; the substrate having a radiation-curable adhesive layer formed thereon which comprises: 100 parts by weight of an acrylic adhesive; 5 to 500 parts by weight of at least one isocyanurate compound selected from the group consisting of: tris (acryloxyethyl) isocyanurate, tris (methacryloxyethyl) isocyanurate, tris-4-acryloxy-n-butyl isocyanurate, tris (1,3-diacryloxy-2-propyloxycarbonylamino-n-hexyl) isocyanurate, tris (1-acryloxy-3-methacryloxy-2-propyloxycarbonylamino-n-hexyl) isocyanurate, and bis (2-acryloxyethyl)-2-(5-acryloxy)hexyloxyethyl isocyanurate; and 0.5 to 100 parts by weight of a urethane acrylate compound having carbon-carbon double bonds, per 100 parts by weight of the acrylic adhesive. The radiation-curable, pressure-sensitive adhesive tape as claimed in claim 16, wherein the radiation-curable adhesive layer comprises 60 to 150 parts by weight of isocyanurate compounds for 100 parts by weight of the acrylic adhesive. The radiation-curable, pressure-sensitive adhesive tape as claimed in claim 16, wherein the radiation-curable adhesive layer comprises 10 to 100 parts by weight of the urethane acrylate compound for 100 parts by weight of the acrylic adhesive. The radiation-curable, pressure-sensitive adhesive tape as claimed in claim 16, wherein the urethane acrylate compound after curing by irradiation has a tensile strength of 100 kg/cm² or below, and a tensile elongation at breaking of at least 50%. A radiation-curable, pressure-sensitive adhesive tape which comprises a radiation-transmitting substrate having a radiation-curable adhesive layer formed thereon which comprises: 100 parts by weight of an acrylic adhesive; 5 to 500 parts by weight of at least one cyanurate and/or isocyanurate compound selected from the group consisting of: tris (acryloxyethyl) isocyanurate, tris (methacryloxyethyl) isocyanurate, tris-4-acryloxy-n-butyl isocuanurate, tris (1,3-diacryloxy-2-propyloxycarbonylamino-n-hexyl) isocyanurate tris (1-acryloxy-3-methacryloxy-2-propyloxycarbonylamino-n-hexyl) isocyanurate, and bis (2-acryloxyethyl)-2-(5-acryloxy)hexyloxyethyl isocyanurate; 0.5 to 100 parts by weight of a urethane acrylate compound having carbon-carbon double bonds, per 100 parts by weight of the acrylic adhesive; and 0.01 to 20 parts by weight of a silicone acrylate compound, per 100 parts by weight of the acrylic adhesive. The radiation-curable, pressure-sensitive adhesive tape as claimed in claim 20, wherein the radiation-transmitting substrate is a multi-layer film composed of at least two different layers. The radiation-curable, pressure-sensitive adhesive tape as claimed in claim 20, wherein the radiation transmitting substrate is a multi-layer film made of at least three radiation-transmitting resin layers with poly(vinyl chloride) and/or an elastomer used as an intermediate layer. The radiation-curable, pressure-sensitive adhesive tape as claimed in claim 20, wherein the radiation-curable adhesive layer comprises 60 to 150 parts by weight of cyanurate or isocyanurate compounds for 100 parts by weight of the acrylic adhesive. The radiation-curable, pressure-sensitive adhesive tape as claimed in claim 20, wherein the radiation-curable adhesive layer comprises 10 to 100 parts by weight of the urethane acrylate compound for 100 parts by weight of the acrylic adhesive. The radiation-curable, pressure-sensitive adhesive tape as claimed in claim 20, wherein the urethane acrylate compound after curing by irradiation has a tensile strength of 100 kg/cm² or below, and a tensile elongation at breaking of at least 50%. A radiation-curable, pressure-sensitive adhesive tape which comprises a radiation-curable adhesive layer that is formed on a radiation-transmitting substrate and that contains 100 parts by weight of an acrylic adhesive, 5 to 500 parts by weight of at least one compound selected from the group consisting of cyanurate compounds, isocyanurate compounds, polyacrylates of aliphatic polyols and/or polymethacrylates of aliphatic polyols and 0.01 to 20 parts by weight of a silicone acrylate compound. The radiation-curable, pressure-sensitive adhesive tape as claimed in claim 26, the radiation-curable adhesive layer comprises 60-150 parts by weight of cyanurate or isocyanurate compound for 100 parts by weight of acrylic adhesive. The radiation-curable, pressure-sensitive adhesive tape as claimed in claim 26, wherein the radiation-curable adhesive layer further comprises 0.5 to 4 parts by weight of silicone acrylate compound for 100 parts by weight of acrylic adhesive. The radiation-curable, pressure-sensitive adhesive tape as claimed in claim 26, which comprises a separator film on the radiation-curable adhesive layer. The radiation-curable, pressure-sensitive adhesive tape as claimed in claim 26, wherein the radiation is ultraviolet ray.

Inventors: FUNAYAMA YOSHIYUKI, ISHIWATA SHINICHI, IWAMOTO KAZUSHIGE, NAKAE HIROYUKI, NOGUCHI ISAMU, UEYAMA MICHIO - RUNE-KAMIHOSHI, FUNAYAMA, YOSHIYUKI, ISHIWATA, SHINICHI, IWAMOTO, KAZUSHIGE, NAKAE, HIROYUKI, NOGUCHI, ISAMU, UEYAMA, MICHIO 3-410, RUNE-KAMIHOSHIKAWA
Applicants: FURUKAWA ELECTRIC CO LTD, THE FURUKAWA ELECTRIC CO., LTD.
Application year: 1988
Main classification: C09J7
IPC codes: C09J4, C09J7