A process for the production of flexographic printing plates by laser engraving, in which the recording layer of a crosslinkable, laser-engravable flexographic printing element is crosslinked by the combination of a full-area crosslinking step with a crosslinking step which only acts at the surface, and a printing relief is engraved into the crosslinked recording layer by means of a laser, and flexographic printing plates obtainable by the process.

The present invention relates to a process for the production of flexographic printing plates by laser engraving in which the recording layer of a crosslinkable, laser-engravable flexographic printing element is crosslinked by the combination of a full-area crosslinking step with a crosslinking step acting only at the surface, and a printing relief is engraved into the crosslinked recording layer by means of a laser. The present invention furthermore relates to flexographic printing plates which can be produced by the process.
In the technique of laser direct engraving for the production of relief printing plates, for example flexographic printing plates, a relief which is suitable for printing is engraved directly into a relief layer which is suitable for this purpose. With the appearance of improved laser systems, this technique is increasingly also attracting commercial interest.
For the production of flexographic printing plates by laser engraving, it is in principle possible to employ commercially available photopolymerizable flexographic printing elements. U.S. Pat. No. 5,259,311 discloses a process in which, in a first step, the flexographic printing element is photochemically crosslinked by full-area irradiation and, in a second step, a printing relief is engraved by means of a laser.
EP-A 640 043 and EP-A 640 044 disclose single-layer or multilayer elastomeric laser-engravable recording elements for the production of flexographic printing plates. The elements consist of xe2x80x9creinforcedxe2x80x9d elastomeric layers. For the production of the layer, use is made of elastomeric binders, in particular thermoplastic elastomers, for example SBS, SIS or SEBS block copolymers. In addition, the layer may comprise IR radiation-absorbent, generally strongly colored substances. The so-called reinforcement increases the mechanical strength of the layer. The reinforcement is achieved either by means of fillers, photochemical or thermochemical crosslinking, or combinations thereof.
EP-B 640 043 also discloses, on page 8, lines 52-59, various techniques for removing surface tackiness of reinforced laser-engravable flexographic printing elements, including exposure to UV-C light or treatment with bromine or chlorine solutions. The irradiation can be carried out before or after the laser engraving of the printing relief. As shown in the cited specification, treatment of this type for removing surface tackiness does not, however, represent further photochemical or thermochemical crosslinking of the relief layer.
The relief layers of laser-engravable flexographic printing elements should in the ideal case not melt during the laser engraving, but instead a direct transition of the degradation products into the gas phase should if possible take place. Melting of the layer may result in formation of melt borders around the printing elements, and the edges of the relief elements become less sharp. Flexographic printing plates having irregularities of this type give prints of worse quality than with printing plates without such defects.
The comparatively soft relief layers of flexographic printing plates, in particular those having thermoplastic elastomers as binders, tend to form melt borders during laser engraving.
Although this problem can generally be at least greatly reduced and in some cases even avoided by using very large amounts of IR absorbers, such as carbon black, in the order of from 30 to 50% by weight of all constituents of the layer, excessively high contents of IR absorber are, however, disadvantageous since the laser-engravable layer should not only be as sensitive as possible to laser radiation, but must also achieve the mechanical and printing performance features of conventionally produced flexographic printing plates. Excessively high absorber contents result, for example, in an impairment in important properties, such as elasticity, flexibility, cliche hardness and ink transfer behavior of the finished flexographic printing plate. In addition, the edges of the relief elements tend to fray if the IR absorber contents are too high.
Furthermore, it is in certain cases also extremely attractive to omit the addition of IR absorbers completely. Although the sensitivity of conventional thermoplastic-elastomeric binders to the radiation of Nd:YAG lasers is poor, the sensitivity to CO2 is at least sufficiently good that commercially available photopolymeric flexographic printing elements that have been exposed to actinic light over the entire area can in principle be engraved by means of CO2 lasers even without the need to add additional IR absorbers, as disclosed, for example, in U.S. Pat. No. 5,259,311. Although the engraving rate by CO2 lasers is not always ideal without additional absorbers, the omission of strongly colored absorbers has the advantage that laser-engravable flexographic printing elements can be produced in the conventional manner by photopolymerization, and the person skilled in the art can continue to utilize his entire knowledge on the formulation of photopolymerizable recording layers for flexographic printing, the structure-property relationships and production technology.
It is an object of the present invention to provide a process for the production of flexographic printing plates by laser engraving by means of which the occurrence of melt borders can be prevented in a simple and straightforward manner without mechanical or printing performance features being impaired compared with those of conventional flexographic printing plates. In particular, it should be possible to use the process for transparent flexographic printing elements which contain no colored absorbers for laser radiation.
We have found that this object is achieved by a process for the production of flexographic printing plates by laser engraving in which the recording layer of a laser-engravable flexographic printing element is crosslinked by the combination of a full-area crosslinking step with a crosslinking step acting only at the surface, and a printing relief is engraved into the crosslinked recording layer by means of a laser. In a further aspect, we have found flexographic printing plates which can be produced by the process.
In a particular embodiment of the process according to the invention, the crosslinking step acting only on the surface is carried out through the action of UV-C radiation according to certain boundary conditions.
Surprisingly, it has been found that the novel combination of two different crosslinking steps significantly improves the quality of the resultant print relief compared with a printing relief which has been crosslinked only once. In particular, melt borders which impair the print appearance are almost completely prevented without the mechanical properties of the print relief, such as hardness, flexibility or rebound resilience, being impaired. This effect is evident in a particularly positive manner in the case of flexographic printing elements without absorbers for laser radiation.
The following details apply to the invention:
The term xe2x80x9claser-engravablexe2x80x9d is taken to mean that the relief layer has the property of absorbing laser radiation, in particular the radiation from an IR laser, so that it is removed or at least delaminated at the points at which it is exposed to a laser beam of sufficient intensity. The layer is preferably evaporated or decomposed thermally or oxidatively in advance without melting, so that its decomposition products in the form of hot gases, vapors, fumes or small particles, can be removed from the layer.
Examples of suitable dimensionally stable supports for the crosslinkable, laser-engravable flexographic printing element employed as starting material are plates, films and conical and cylindrical tubes (sleeves) made from metals such as steel, aluminum, copper or nickel or plastics, such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate, polyamide, polycarbonate, optionally also woven and nonwoven fabrics, such as woven glass fiber fabrics, and composite materials, for example made from glass fibers and plastics. Suitable dimensionally stable supports are in particular dimensionally stable support films, such as polyester films, in particular PET or PEN films.
Of particular advantage are flexible metallic supports. For the purposes of the present invention, the term xe2x80x9cflexiblexe2x80x9d is taken to mean that the supports are sufficiently thin that they can be bent around the printing cylinder. On the other hand, however, they are also dimensionally stable and sufficiently thick that the support is not kinked during production of the laser-engravable element or during mounting of the finished printing plate on the printing cylinder.
Suitable flexible metallic supports are in particular thin sheets or foils made from steel, preferably stainless steel, magnetizable spring steel, aluminum, zinc, magnesium, nickel, chromium or copper, it also being possible for the metals to be alloyed. It is also possible to employ combined metallic supports, for example steel sheets coated with tin, zinc, chromium, aluminum, nickel or also combinations of various metals, or also metal supports obtained by lamination of identical or different metal sheets. It is furthermore also possible to employ pretreated sheets, for example phosphated or chromatized steel sheets or anodized aluminum sheets. In general, the sheets or foils are degreased before use. Preference is given to sheets made from steel or aluminum. Particular preference is given to magnetizable spring steel.
The thickness of flexible metal supports of this type is usually from 0.025 mm to 0.4 mm and depends, besides on the desired degree of flexibility, also on the type of metal employed. Supports made from steel usually have a thickness of from 0.025 to 0.25 mm, in particular from 0.14 to 0.24 mm. Supports made from aluminum usually have a thickness of from 0.25 to 0.4 mm.
The starting material for the process furthermore comprises at least one crosslinkable, laser-engravable recording layer, which is applied to the support either directly or optionally via further layers. The crosslinkable recording layer comprises at least one binder. It may comprise further components for supporting the crosslinking, for example polymerizable monomers or oligomers, and/or compounds which are able to initiate the crosslinking reaction, for example initiators.
The recording layer can be crosslinked by high-energy radiation and/or thermally. Crosslinking by high-energy radiation can be carried out, in particular, photochemically by means of short-wave visible or long-wave ultraviolet light. However, radiation of higher energy, such as short-wave UV light or X-rays, an electron beam orxe2x80x94given suitable sensitizationxe2x80x94also longer-wave light is of course in principle also suitable. Thermal crosslinking is carried out, in particular, by warming, but can in principle also be carried out at room temperature.
Particularly suitable binders for the layer are elastomeric binders. However, it is in principle also possible to employ non-elastomeric binders. The crucial factor is ultimately that the crosslinkable recording layer has elastomeric properties after crosslinking step (a) has been carried out. The recording layer may, for example, take on elastomeric properties through the addition of plasticizers, or it is also possible to employ crosslinkable oligomers, which only form an elastomeric network through reaction with one another.
Suitable elastomeric binders for the laser-engravable layer are, in particular, polymers which comprise 1,3-diene monomers, such as isoprene or butadiene. Examples which may be mentioned are natural rubber, polyisoprene, styrene-butadiene rubber, nitrile-butadiene rubber, butyl rubber, styrene-isoprene rubber, polynorbornene rubber or ethylene-propylene-diene rubber (EPDM). However, it is also in principle possible to employ ethylene-propylene, ethylene-acrylate, ethylene-vinyl acetate or acrylate rubbers. Also suitable are hydrogenated rubbers or elastomeric polyurethanes.
It is also possible to employ modified binders in which crosslinkable groups are introduced into the polymeric molecule by grafting reactions.
Particularly suitable elastomeric binders are thermoplastic elastomeric block copolymers comprising alkenylaromatic compounds and 1,3-dienes. The block copolymers can be either linear block copolymers or free-radical block copolymers. They are usually three-block copolymers of the A-B-A type, but can also be two-block copolymers of the A-B type, or those comprising a plurality of alternating elastomeric and thermoplastic blocks, for example A-B-A-B-A. It is also possible to employ mixtures of two or more different block copolymers. Commercially available three-block copolymers frequently comprise certain proportions of two-block copolymers. The diene units may be 1,2- or 1,4-linked. They may also be fully or partially hydrogenated. It is possible to employ both block copolymers of the styrene-butadiene and of the styrene-isoprene type. They are commercially available, for example under the name KRATON(copyright). It is furthermore possible to employ thermoplastic-elastomeric block copolymers having end blocks of styrene and a random styrene-butadiene central block which are commercially available under the name STYROFLEX(copyright).
The type and amount of binder employed are selected by the person skilled in the art depending on the desired properties of the printing relief of the flexographic printing element. In general, an amount of from 50 to 95% by weight of binder, based on the amount of all constituents of the laser-engravable layer, has proven successful. It is also possible to employ mixtures of different binders.
The crosslinkable, laser-engravable layer has crosslinkable groups which are able to form polymeric networks thermally, photochemically or under the action of high-energy radiation, either directly or by means of suitable initiators. Crosslinkable groups may be constituents of the elastomeric binder itself. The crosslinkable groups can be in the main chain, or can be terminal groups and/or pendant groups. It is of course possible for an elastomeric binder to have crosslinkable groups both as side groups and terminally or in the main chain.
It is furthermore possible to add monomeric or oligomeric compounds, each having crosslinkable groups, to the laser-engravable recording layer.
The number and type of the further components for crosslinking of the layer depends on the desired crosslinking method and are selected correspondingly by the person skilled in the art.
In the case of photochemical crosslinking, the recording layer comprises at least one photoinitiator or a photoinitiator system. Suitable initiators for the photopolymerization are, in a known manner, benzoin or benzoin derivatives, such as xcex1-methylbenzoin or benzoin ethers, benzil derivatives, for example benzil ketals, acylarylphosphine oxides, acylarylphosphinic acid esters, and polycyclic quinones, without the list being restricted thereto. Preference is given to photoinitiators which have high absorption between 300 and 450 nm.
If the polymeric binder has crosslinkable groups to a sufficient extent, the addition of additional crosslinkable monomers or oligomers is unnecessary. In general, however, further polymerizable compounds or monomers are added for photochemical crosslinking. The monomers should be compatible with the binders and have at least one polymerizable, olefinically unsaturated group. Esters or amides of acrylic acid or methacrylic acid with monofunctional or polyfunctional alcohols, amines, aminoalcohols or hydroxyethers and -esters, styrene or substituted styrenes, esters of fumaric or maleic acid or allyl compounds have proven particularly advantageous. Examples of suitable monomers are butyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol diacrylate, trimethylolpropane triacrylate, dioctyl fumarate and N-dodecylmaleimide. It is also possible to employ suitable oligomers having olefinic groups. It is of course also possible to employ mixtures of different monomers or oligomers, provided that these are compatible with one another. The total amount of any monomers employed is determined by the person skilled in the art depending on the desired properties of the recording layer. In general, however, 30% by weight, based on the amount of all constituents of the laser-engravable laser, should not be exceeded.
The thermal crosslinking can on the one hand be carried out analogously to the photochemical crosslinking using a thermal polymerization initiator instead of a photoinitiator. Polymerization initiators which can be employed are in principle commercially available thermal initiators for free-radical polymerization, for example suitable peroxides, hydroperoxides or azo compounds. As in photochemical crosslinking, additional monomers or oligomers can be employed, depending on the nature of the binder.
The thermal crosslinking may furthermore be carried out by adding a thermally curing resin, for example an epoxy resin, to the layer or by thermally crosslinking binders themselves containing sufficient amounts of polymerizable groups directly by means of suitable crosslinking agents.
The crosslinkable, laser-engravable flexographic printing element may furthermore comprise an absorber for laser radiation. It is also possible to employ mixtures of different absorbers for laser radiation. Suitable absorbers for laser radiation have high absorption in the region of the laser wavelength. In particular, suitable absorbers are those which have high absorption in the near infrared, and in the long-wave VIS region of the electromagnetic spectrum. Absorbers of this type are particularly suitable for the absorption of the radiation from Nd:YAG lasers (1064 nm) and from IR diode lasers, which typically have wavelengths of between 700 and 900 nm and between 1200 and 1600 nm.
Examples of suitable absorbers for the laser radiation are dyes which absorb strongly in the infrared spectral region, for example phthalocyanines, naphthalocyanines, cyanines, quinones, metal/complex dyes, for example dithiolenes, or photochromic dyes.
Other suitable absorbers are inorganic pigments, in particular intensely colored inorganic pigments, for example chromium oxides, iron oxides, carbon black or metallic particles.
Particularly suitable absorbers for laser radiation are finely divided carbon black grades having a particle size of from 10 to 50 nm.
The amount of optionally added absorber is selected by the person skilled in the art depending on the properties of the laser-engravable recording element that are desired in each case. In this connection, the person skilled in the art will take into account that the added absorbers influence not only the rate and efficiency of engraving of the elastomeric layer by laser, but also other properties of the relief printing element obtained as the end product from the process, for example its hardness, elasticity, thermal conductivity or ink transfer behavior. In general, it is therefore advisable to employ not more than a maximum of 20% by weight, preferably not more than 10% by weight and very particularly preferably not more than a maximum of 5% by weight of absorber for laser radiation. However, it is of course also possible to employ laser-engravable elements having higher contents of absorber in individual cases for the process.
In general, it is not advisable to add absorbers for laser radiation which also absorb in the UV region to recording layers which are to be photochemically crosslinked, since this greatly impairs the photopolymerization.
The laser-engravable layers according to the invention may furthermore also comprise additives and auxiliaries, for example dyes, dispersion aids, antistatics, plasticizers or abrasive particles. However, the amount of such additives should generally not exceed 10% by weight, based on the amount of all components of the crosslinkable, laser-engravable layer of the recording element.
The crosslinkable, laser-engravable recording layer may also be built up from a plurality of recording layers. These laser-engravable, crosslinkable sub-layers may have the same, approximately the same or different material compositions. A multilayer structure of this type, particularly a two-layer structure, is sometimes advantageous since it allows surface properties and layer properties to be modified independently of one another in order to achieve an optimum print result. For example, the laser-engravable recording element may have a thin laser-engravable upper layer whose composition has been selected with respect to optimum ink transfer, while the composition of the underlying layer has been selected with a view to optimum hardness or elasticity.
The thickness of the crosslinkable, laser-engravable recording layer or all recording layers together is generally from 0.1 to 7 mm. The thickness is selected suitably by the person skilled in the art depending on the desired application of the printing plate.
The crosslinkable, laser-engravable flexographic printing element employed as starting material may optionally comprise further layers.
Examples of such layers include an elastomeric underlayer of a different formulation which is located between the support and the laser-engravable layer(s) and need not necessarily be laser-engravable. Underlayers of this type allow the mechanical properties of the relief printing plates to be modified without affecting the properties of the actual printing relief layer.
The same purpose is served by so-called elastic substructures, which are located below the dimensionally stable support of the laser-engravable recording element, i.e. on the opposite side to the laser-engravable layer. Elastic substructures or elastic underlayers may be crosslinkable and likewise crosslinked during crosslinking step (a). However, they may also already be crosslinked and be joined to the other layers, for example by lamination.
Further examples include adhesion layers, which bond the support to overlying layers or various layers.
Furthermore, the laser-engravable flexographic printing element may be protected against mechanical damage by a protective film, for example consisting of PET, which is located on the uppermost layer in each case, and which in each case must be removed before the laser engraving. In order to simplify removal, the protective film may also be siliconized or provided with a suitable release layer.
The laser-engravable flexographic printing element can be produced, for example, by dissolving or dispersing all components in a suitable solvent and casting the solution or dispersion onto a support. In the case of multilayer elements, a plurality of layers can be cast one on top of the other in a manner known in principle. Alternatively, the individual layers can be cast, for example, onto temporary supports, and the layers subsequently bonded to one another by lamination. Photochemically crosslinkable systems in particular can be produced by extrusion and/or calendering. This technique can in principle also be employed for thermally crosslinkable systems so long as use is only made of components which do not yet crosslink at the process temperature.
The crosslinkable, laser-engravable flexographic printing element employed as starting material is crosslinked over the entire area in the first process step (a) of the process according to the invention. This crosslinking step acts on the entire volume of the layer.
Depending on the type of crosslinking system selected, the recording element is to this end irradiated with high-energy radiation, for example with UV-A radiation or with electron beams, or the recording element is warmed. The irradiation or warming should be carried out as uniformly as possible in order to avoid as far as possible inhomogeneities in the degree of crosslinking of the layer. Uniform irradiation can also be achieved, for example, by irradiating the layer on the one hand from the upper side and in addition from the lower side through the dimensionally stable support. A prerequisite for this is of course that the support is transparent to the respective radiation. It is of course also possible for the two crosslinking methods to be combined with one another. Although homogeneity is desirable, the present invention does not exclude the crosslinking density having inhomogeneities. For example, the crosslinking density may have a gradient.
It is essential for the process according to the invention that not all groups in the layer which are crosslinkable in principle are reacted during said full-area crosslinking during process step (a) with formation of a polymeric network, but instead as yet unreacted, crosslinkable groups remain in the crosslinked recording layer.
This incomplete reaction can be achieved, for example, by selecting the irradiation time or the duration of the warming in such a way that the reaction is still incomplete when the warming or irradiation of the flexographic printing element is terminated. It can also be effected, for example, by restricting the amount of initiator, so that the latter is used up before complete conversion of crosslinkable groups is achieved.
The incomplete reaction can also be achieved by employing a laser-engravable flexographic printing element whose layer has crosslinkable groups of different reactivity, and selecting the reaction conditions in such a way that preferentially only one type of crosslinkable groups reacts during the crosslinking reaction, while the other type is not yet reacted. The recording layer may also have, for example, both thermally and photochemically crosslinkable groups and be only thermally or only photochemically crosslinked, so that groups of one type remain over.
The methods can of course also be combined with one another. The degree of reaction during the crosslinking is prescribed by the person skilled in the art depending on the desired properties of the crosslinked layer.
Crosslinking step (b) which only acts at the surface only affects parts of the laser-engravable layer. Further crosslinking does not take place throughout the laser-engravable layer, but instead only in a part-volume of the layer. The effectiveness of the crosslinking step (b) has a penetration depth which is limited when viewed from the surface of the laser-engravable recording layer, so that the uppermost zone of the laser-engravable layer is crosslinked to a greater extent than would be the case on exclusive use of process step (a). All or some of the crosslinkable groups which are not reacted in process step (a) are reacted here.
Process step (b) is preferably carried out after process step (a), but the two process steps can also be carried out simultaneously. In special cases, (b) can be carried out first, followed by (a).
The width of the zone within which the crosslinking density is raised by step (b) or the effective penetration depth of the measure taken for crosslinking is generally at least 5 xcexcm and not greater than 200 xcexcm, seen from the surface of the recording layer, without the width definitely being limited thereto. The penetration depth is preferably 5-150 xcexcm and particularly preferably 5-100 xcexcm.
If the starting materials employed for the process according to the invention are multilayer laser-engravable recording elements, it is also possible for a plurality of layers, depending on the respective thickness of the layer, to be affected by process step (b). It goes without saying that the crosslinking density of the recording layers of different composition may be different. The process according to the invention increases the crosslinking density in each of these layersxe2x80x94up to the maximum penetration depthxe2x80x94beyond the extent achieved in process step (a).
The transition from the zone whose crosslinking density is increased during step (b) beyond the extent from process step (a) to the zone which is no longer affected by process step (b) may be abrupt, comparatively steep or gradual. The penetration depth is defined using the inflexion point of the crosslinking density as a function of the penetration depth.
A plurality of methods are available to the person skilled in the art for carrying out process step (b). The choice of method is restricted only inasmuch as the method must not adversely affect other properties of the flexographic printing element.
For example, the flexographic printing element can be irradiated at the surface with high-energy radiation or warmed at the surface. The element can also be treated with polymerization initiators or crosslinking agents, optionally followed by irradiation or warming.
In the case of laser-engravable flexographic printing elements which also have photochemically crosslinkable groups, an embodiment which has proven particularly successful is one in which the crosslinked laser-engravable flexographic printing element is irradiated with UV light having a wavelength of from 200 nm to 300 nm, so-called UV-C light. The method is particularly suitable if the layer has olefinic double bonds as crosslinkable groups. Due to the comparatively strong scattering of the short-wave light in the layer, the intensity of UV-C radiation drops considerably with increasing penetration depth, so that only the uppermost zone of the flexographic printing element is effectively crosslinked.
The requisite exposure time depends on the power and arrangement of the UV-C light source and on the type of flexographic printing element, in particular on its content of IR absorbers. The irradiation with UV-C also results in the effect according to the invention in the case of more highly filled plates.
It should expressly be pointed out at this point that the surface crosslinking with UV-C light does not require that the layer must have been photochemically crosslinked in the preceding process step (a). It is also possible to employ thermally crosslinked recording elements, provided that they still have crosslinkable olefinic double bonds.
Crosslinking by means of UV-C light is possible without an additional photoinitiator. However, a particularly advantageous embodiment of the invention is to employ a laser-engravable recording element whose recording layer comprises a photoinitiator which is activated by light having a wavelength of from 200 to 300 nm. An initiator of this type is added to the laser-engravable layer during the production process and is converted into the layer together with all other components, or the layer is treated with the initiator just before step (b). In the case of multilayer recording elements, it is furthermore advantageous not to add said photoinitiator to all layers, but only to the uppermost layer(s).
Examples of suitable initiators which absorb in the UV-C region include aryl ketones of the general formula Rxe2x80x94CO-aryl, where R is, in particular, alkyl groups, such as methyl, ethyl or propyl, or alternatively substituted alkyl groups, such as a benzyl group. The aryl radical may also be further substituted.
If process step (a) is carried out photochemically, the full-area crosslinking should generally not be carried out with UV-C light, although an embodiment of this type should not be excluded for special cases.
The additional crosslinking in the uppermost zone can also be carried out by surface warming of the layer, which causes thermally crosslinkable groups still present to crosslink further. The surface warming can be carried out, for example, by brief irradiation with IR radiation. Particularly suitable for this purpose are high-power heat radiators, with which the surface of the element can be warmed briefly, but strongly, for example by passing the recording elements slowly under an IR emitter on a conveyor belt. It is important that uniform warming of the element as a whole is avoided. The surface warming can also be carried out, for example, by treatment with microwaves. It is furthermore possible to add to the recording element an additional thermal polymerization initiator which only decomposes at the temperatures of the surface warming, but not at the production temperatures of the layer. In the case of multilayer flexographic printing elements, it is furthermore advantageous not to add said initiator to all layers, but only to the uppermost layer(s).
It is also possible not to add polymerization initiators to the laser-engravable recording layer, but instead to treat the surface of the laser-engravable flexographic printing element with a suitable polymerization initiator. The surface can, for example, be brought into contact with a solution of the initiator. Solvents can be employed here which slightly swell the surface of the recording element in order to facilitate penetration of the polymerization initiator. However, excessive swelling should be avoided since otherwise the printing properties of the finished flexographic printing plate could be impaired. Examples of polymerization initiators include thermally labile organic peroxides or peresters, for example those which are able to form t-butoxy, cumyloxy, methyl or phenyl radicals, hydrogen peroxide or inorganic peroxides. It is furthermore possible to employ thermally labile azo compounds, for example azobisisobutyronitrile or similar compounds. Further examples include halogens in pure or dissolved form, sulfur/halogen compounds or redox initiator systems.
For the dissolution or in order to complete the surface crosslinking, the laser-engravable flexographic printing element can, after the treatment with initiator, be irradiated at the surface or warmed at the surface, again as mentioned above.
In process step (c), a printing relief is engraved into the crosslinked, laser-engravable layer by means of a laser. It is advantageous to engrave image elements in which the edges of the pixels initially fall off vertically and only spread out in the lower region of the image element. This results in a good shoulder shape of the image dots, but nevertheless low dot gain. However, it is also possible to engrave image dot edges of a different shape.
Particularly suitable for laser engraving are CO2 lasers having a wavelength of 10,640 nm, but also, depending on the material situation, Nd:YAG lasers (1064 nm) and IR diode lasers or solid-state lasers, which typically have wavelengths of from 700 to 900 nm and from 1200 to 1600 nm. However, it is also possible to employ lasers having shorter wavelengths, provided that the lasers have adequate intensity. For example, a frequency-doubled (532 nm) or frequency-tripled (355 nm) Nd:YAG laser or excimer lasers (for example 248 nm) can also be employed. The image information to be engraved is transferred directly from the layout computer system to the laser apparatus. The lasers can be operated either continuously or in pulsed mode.
In general, the flexographic printing plate obtained can be employed directly. If desired, however, the flexographic printing plate obtained can subsequently be cleaned. A cleaning step of this type removes layer constituents which have been detached, but have not yet been completely removed from the plate surface. In general, simple treatment with water or alcohols is entirely sufficient.
The process according to the invention can be carried out in a single production operation in which all process steps are carried out one after the other. However, the process can also advantageously be terminated after process step (b). The crosslinked, laser-engravable recording element can be packaged and stored and only converted further into a flexographic printing element by laser engraving at a later time. It is advantageous here to protect the flexographic printing element, for example using a temporary cover film, for example made of PET, which must of course be removed again before the laser engraving.
The advantages of the process according to the invention with two-stage crosslinking are evident from the flexographic printing plate obtained. Due to process step (b), the surface of the laser-engravable flexographic printing element is cured without thereby impairing the elastic properties of the layer. The layer crosslinked in this way can be engaged by lasers without causing melt borders by the engraving process.

Method for laser engraving flexographic printing forms, and printing forms obtained thereby


A portable, pocketbook-sized computer is provided with the features of a palmtop computer as well as video conferencing ability. A hinged design is provided so that the unit can fold shut. On one side, a computer unit is housed, including a full keyboard and a monitor, while the other side houses a mobile telephone unit, including a numeric keyboard and similarly sized monitor. The spine included a rotating camera. The units communicated so that the monitors can serve as video phone monitors, each showing one of the communicating parties. In a computer mode, both monitors can operate to display text on figures. Recessed character keys and raised operator keys enable rapid operation despite closely spaced keys. A ball-ended pen is provided for this purpose, sized to fall into one of the recesses at a time. Additionally, the pen is provided with wireless communication with the computer unit to silently alert the owner of incoming calls, or to use as a microphone.

This application claims the foreign priority benefit under 35 U.S.C. xc2xa7119 to German Utility Model Application No. 200 21 842.5, filed Dec. 21, 2000.
1. Field of the Invention
The invention relates to a palmtop computer having the features and capabilities of video conferencing.
2. Background of the Invention
Today""s office computers and smaller notebook computers work mainly with CPU, RAM storage, hard drive storage and exchangeable storage media. Such computers are relatively large, heavy and have a relatively large energy consumption. The current trend is toward smaller computer units.
EP 0 750 245 A1 discloses a small computer with a notebook design. It is operated with a special electronic pen using a sensitive monitor surface for input and output. This monitor is framed with a flat frame and attached to a rectangular base housing. At one edge of the computer housing the flat frame with the monitor is hinged as a lid. The hinge is built like a pipe, and in the hollow space thereof a telescopic video camera is stored, which is pulled out for use. This notebook computer uses a completely different data input procedure from the established data input procedure of other computers, so that the user has to learn a new way of working. The user""s hand and the pen that is employed at least partly obscure the view of the monitor. A further disadvantage of this computer design is that the usable area of one monitor has to be divided among input and output. This problem is especially relevant for videoconferences with more than one communication partner.
The object of the present invention is to provide a small, lightweight and handy communications computer that affords effective usage and ergonomic operating functions.
This object may be achieved by a computer unit which is provided with a monitor and with a integrated keyboard that is small, but with a layout similar to well-known desktop and laptop keyboards, a mobile telephone unit with a second monitor and with a numeric keyboard that serves to dial telephone numbers and also as a numeric keyboard for the computer unit, and a digital video camera with a lens head having limited rotation.
All three components are connected to each others, such as by printed and flexible wiring or by the latest Bluetooth(trademark) techniques. The computer unit and mobile telephone unit each are provided with a monitor and each has its own input device, to allow data input in an ergonomic way.
The two monitors are connected to each other such that the first monitor shows a picture of the built-in video camera, while the second monitor shows the incoming picture. This allows for telephone communication between two partners or as a conference connection with many communication partners.
The outside design of the preferred embodiment uses a housing like a hardcover pocketbook with two hinges, connecting one back side or spine and two wings. The three inside units each have their own metal or plastic housing, for example in the shape and design depicted in the attached drawings. The complete unit is a small size, low weight, low energy consuming communication computer.
A special feature of the design is the lens head of the video camera, which rotates up to 200 degrees, thus making it possible to show not only the face of the user, but also items, letters or drawings placed on the desktop without moving the whole unit.
It is preferable that this computer have at least one processor and as much volatile memory (RAM) as possible, but a smaller amount of permanent storage; this permits a miniaturization of the design and a minimizing of the power consumption. This computer unit needs permanent storage only for the operating system. Application programs and data are imported into the memory as required via the broadband wireless communication connection. After use, this data may be returned to the home or office computer of the user or to a server of any Internet provider, or sent by email to any other address. The RAM is erased when the device is powered down.
One advantage of this device is that each unit has a full-featured keyboard; users are already familiar with the layout from other such keyboards, and so do not need to learn a new method of data input.
The very small computer keyboard preferably has two groups of keys; one group (preferably characters) is recessed from the main computer housing surface and operated, for example, with a 3 mm glass ball fixed to the rear side of a commercial ball pen. The other group (preferably operator and function keys) projects above the main computer housing surface and these keys are spaced widely enough to be operated with one finger. It is also advantageous for left or right handed users in that the user can hold the pen with his preferred hand, while the fingers of the weaker hand operate the operator keys, such as control, alt, shift, tab, enter and option keys.
It also preferable that the mobile telephone unit has a numeric key block that is also recessed and operated with the rear side of the ball pen. This key block is used for dialing telephone numbers as well as being the numeric key block for the computer unit.
Preferably, some special dedicated keys are also provided as main power switches, to operate the video camera, and to control play functions for recording video and audio data.
The cursor control touch pad is preferably operated with the rear end of the ball pen to facilitate exact positioning on the monitor, while the fingers are used to carry out mouse click functions using the keys to the left or right of the touch pad.
The combination or networking of the monitors and/or text input devices is advantageous in distributing key entry operations and in freely selecting one monitor or both monitors for display, which may enhance legibility in some cases. For example, when calculations involving a large amount of numeric entry are carried out, such as the addition of many numbers, the phone-side numeric keypad may be used, and the computer-side monitor may be used to show the process and result. Alternatively, the content of text or Internet pages can be distributed over the two monitors at an enlargement of 200%. Furthermore, one computer task can be displayed on one monitor and a second task can be displayed on the other monitor.
Further features include connecting ports for CD-ROM or DVD drives, hard drives, printers, scanners, professional video and still picture cameras, sensors and other devices. These may be connected via Firewire EEE 1394, USB, or telecom headset connections. These ports are to be seen at the front edges of the unit when it is closed. Advanced Bluetooth(trademark) transmitting techniques may also be integrated.
The computer unit may be connected with the video camera and with the mobile telephone unit most easily and cheaply using flexible printed circuits. However, this internal connection can also be made using Bluetooth(trademark) technology.
The video camera has its processing unit within the upper part of the square camera housing or spine, while the lower part is reserved for the power accumulators. The power accumulators can be charged with a charger unit, which also serves as a stand for the communications computer in its opened configuration. On the stand the communications computer is tilted approximately 10 degrees backward; this position facilitates use as a video telecommunication unit.
When the unit is used to make telephone conferences, it is preferable to provide a traffic light system to regulate communications between the communication partners. Under such a system, the green light indicates xe2x80x9ctalk,xe2x80x9d yellow can indicate xe2x80x9cstand by to talkxe2x80x9d and red for xe2x80x9cdo not talk.xe2x80x9d


There is disclosed an oral cleansing product comprising as an abrasive an alumnina in the form of particles having d10 below 3.5 xcexcm, d50 below 1.0 xcexcm, and a specific surface area below 6 m2/g.

International standard ISO11609 of 1995 contains the following definitions:
Dentifrice: any substance or combination of substances specially prepared for the public for cleaning the accessible surfaces of teeth.
Toothpaste: any semi-solid dentifrice preparation presented in the form of a paste, cream or gel.
This invention is concerned with oral cleansing products, including dentifrices and (to the extent that they are not classed as dentifrices) chewing gum and candy.
An oral cleansing product invariably contains an abrasive powder for cleaning purposes. The cleaning and abrasive properties of the oral cleansing product depend on the concentration of the powder, on the Moh""s hardness of the abrasive, and on the shape and particle size and size distribution of the powder. The cleaning effect of an oral cleansing product concerns its effectiveness in removing adventitious stains and other deposits from the surface of teeth and other parts of oral cavity. The abrasive effect or abrasivity concerns undesired removal of surface components of teeth including enamel and dentine, and undesired damage in the oral cavity. An oral cleansing product having a high cleaning effect generally has a rather high abrasivity, and vice versa. ISO11609 provides methods for testing abrasivity and sets limits on dentifrices marketed in Europe. An earlier British standard BS5136 of 1981 also sets limits on abrasivity by comparison with a standard reference toothpaste, which is also used as a reference in ISO11609, and which has the formulation:
Precipitated calcium carbonate 40% w/w.
Glycol 25% w/w
Sodium carboxymethylcellulose 1.40% w/w
Dodecyl sodium sulphate 1.00% w/w
Sodium silicate (80xc2x0 TW of approximately pH 7) 0.05% w/w
Saccharin sodium 0.15% w/w
Formalin (40% (m/m) formaldehyde) 0.10 w/w
Peppermint flavouring 0.80% w/w
Water 33.05% w/w
Abrasive powders used or contemplated for use in oral cleansing products include silicas, including gels and precipitates, sodium bicarbonate, calcium and magnesium carbonates, calcium phosphates, alumina and hydrates thereof, aluminosilicates, aluminium and magnesium silicates, and thermosetting urea-formaldehyde and other plastics materials. There is a need in the industry for an abrasive for inclusion in oral cleansing products, which provides good cleaning properties, in particular stain removal, while showing relatively low abrasivity. In particular, there is a need for an abrasive which can be incorporated in a concentration large enough to provide an excellent cleaning effect with low abrasivity which nevertheless complies with the abrasivity requirements of the above-stated standard specifications. This invention addresses that need.
U.S. Pat. No. 3,957,968 teaches the use of flat flakes of xcex1-aluminium oxide in toothpaste. The flakes have a median particle size of 2 to 7 xcexcm. U.S. Pat. No. 4,060,599 discloses the use of a finer aluminium oxide (median 1 to 2 xcexcm) and specifically uses Reynolds RC152DBM which has a median size of around 1.7 xcexcm.
U.S. Pat. No. 4,632,826 teaches the use of a weakly calcined alumina polishing agent. This polishing agent consists of 10% to 50% by weight xcex3 aluminium oxide and 50% to 90% by weight xcex1 aluminium oxide.
GB-A-2155333 teaches the use of calcium hydrogenphosphate anhydride and an aluminium oxide having an average particle size of 0.5 xcexcm to 10 xcexcm. The alumina has a high a-content, as measured by X-ray diffraction.
WO-A-95/33441 teaches the use of cationically charged colloids of a metal compound. The colloid has a particle size of 0.001 xcexcm to 0.2 xcexcm.
GB-A-2037162 and GB-A-2009596 disclose the use of hydrated aluminas in dentifrice products.
The phrase xe2x80x9caluminaxe2x80x9d is sometimes loosely used to cover a number of aluminium oxide, oxide hydroxide and trihydroxide compounds. The correct designations and some crystalline phases are shown below:
This invention is concerned with alumina that is essentially Corundum. Corundum is produced by calcination of aluminium trihydroxides and oxide hydroxides. Depending on the form of aluminium trihydroxide and oxide hydroxide starting material, a number of forms of alumina (often described as activated aluminas) are produced before corundum is formed. Another form of alumina chemical is aluminium hydroxide gel, which is often formed by the neutralisation of an aluminium salt solution.
The invention provides an oral cleansing product comprising as an abrasive an alumina in the form of particles having d10 below 3.5 xcexcm, d50 below 1.0 xcexcm, and specific surface area below 6 m2/g.
According to a further aspect of the present invention, there is provided the use of alumina as an abrasive in an oral cleansing product, wherein the alumina is in the form of particles having d10 below 3.5 xcexcm, d50 below 1.0 xcexcm, and a specific surface area below 6 m2/g.
According to a further aspect of the present invention, there is provided the use of alumina as a whitening agent in an oral cleansing product, wherein the alumina is in the form of particles having d10 below 3.5 xcexcm, d50 below 1.0 xcexcm, and a specific surface area below 6 m2/g. In this way the alumina used may serve the purpose of replacing titania or the like in conventional products, thus resulting in a cost saving.
The surface area is measured by the following method. A sample of alumina of sufficient weight to give an estimated surface area of about 0.5 to 25 m2 is degassed in a Micrometrics Desorb 2300B at about 150xc2x0 C. until a stable reading is obtained. The sample is then transferred to a Micrometrics Flowsorb II 2300, cooled and immersed in a mixture of 30% N and 70% He gas. The total amount of N absorbed is measured from the change in thermal conductivity of the gas mixture preferably during desorption as the temperature is raised again to room temperature. Surface area per gram is then calculated from the total gas absorbed and the weight of the sample.
The particle size is measured as follows. Particle size distribution of a sample of alumina is measured in a Sedigraph 5100 instrument supplied, by Micrometrics Products.
The abrasive is preferably an anhydrous alumina, generally a calcined alumina or alternatively a tabular or fused alumina. Calcination is effected at a temperature of at least 900xc2x0 C. Higher calcination temperatures result in harder products. The alumina used in this invention is preferably fairly hard, such as may be obtained by calcination at above 1000xc2x0 C. The alumina in this invention is an xcex1-alumina. Preferably, the xcex1 content is greater than 90%, preferably greater than 93%, even more preferably greater than 95%, as measured by X-ray diffraction. In a preferred embodiment, the xcex3-content is less than 1%.
The abrasive is used in the form of particles having d10 below 3.5 xcexcm, preferably below 2.5 xcexcm. (d10, d50 and d90 are used in conventional manner to indicate that 10, 50 or 90 wt % of the product has a particle size above the stated value). Preferably, the alumina abrasive is a sub-micron product, having d50 of 0.1-1.0 xcexcm. Preferably the alumina abrasive has a relatively narrow particle size distribution, e.g. with d10 being no greater than four times d50.
The alumina abrasive has a specific surface area below 6 m2/g, preferably in the range of 4.5-5.0 m2/g. The specific surface area is related to the aforesaid parameters of hardness (harder products have lower specific surface areas) and particle size (more finely divided products have larger specific surface areas).
Alumina products of the kind described are readily available commercially, for they are produced in substantial quantities mainly for use in refractories and ceramics. Grinding may conveniently be effected by fluid energy or vibratory milling (micronising) or preferably by ball milling.
When an abrasive powder has excellent stain removal properties in one toothpaste, it is generally the case that it will be found to have excellent stain removal properties in other oral cleansing products. Although the abrasivity of an oral cleansing product does depend to a significant extent on the whole formulation, and not merely on the nature and concentration of the abrasive present in it, nevertheless an abrasive which shows high or low abrasivity in one formulation may generally be expected to show correspondingly high or low abrasivity in others.
The alumina abrasive is preferably present in the oral cleansing product at a concentration of 1-15% w/w, preferably higher than 2%, even more preferably higher than 3%, e.g. 3-12% w/w. Toothpastes and other oral cleansing products include a wide variety of components in a wide variety of concentrations. The alumina should be compatible with other ingredients. The following list is intended to be exemplary rather than definitive or restrictive.
Toothpastes are generally water-based. Other dentifrice formulations are typically water-based or are supplied dry and require water for activation. Chewing gums and candies are generally based on natural or synthetic elastomers or gum bases.
A binder or thickener is generally present. Examples of suitable materials are carboxyvinyl polymers, carrageenan, hydroxyethyl cellulose and water soluble salts of cellulose ethers such as sodium carboxymethylcellulose and sodium carboxymethyl hydroxyethyl cellulose. Natural gums and colloidal silica or silicate materials can also be used. Binders or thickeners are generally present in an amount from about 0.15 to about 5.0% w/w of the total composition.
A humectant is also generally used to keep the formulation from hardening on exposure to air. Examples of suitable humectants are glycerine, sorbitol, xylitol, polyethylene glycols and propylene glycol. Humectants are generally present in an amount from about 10% to about 70% w/w of the weight of the composition.
One or more particulate materials, regarded as abrasives or abrasive polishers or fillers, are also present. The alumina abrasive described above is one such, but others may also be present as noted above. Examples are:
Silicas, including gels and precipitates, sodium bicarbonate, calcium and magnesium carbonates, dicalcium phosphate dihydrate, alumina and hydrates thereof, aluminosilicates, aluminium and magnesium silicates, and thermosetting urea-formaldehyde and other plastics materials. It is preferred that the alumina is not present in combination with calcium hydrogenphosphate anhydride.
Abrasives are generally present at a level of about 10% to about 70%, preferably from about 15% to about 25%, w/w of the formulation.
A source of fluoride ion is preferably provided. Regulatory authorities in various countries may stipulate a maximum and/or a minimum total fluoride ion concentration.
Chewing gums are generally based on one or more of: natural and synthetic elastomers e.g. polybutene or polyisobutene, which may be softened with vegetable fats or oils or plasticisers; waxes; humectants such as xylitol; natural and synthetic resins and gum bases such as chicle.
Other components which may also be included in oral cleansing products in accordance with conventional practice, include sweeteners, flavours, colours, peroxides or other bleaching agents, anti-calculus agents, anti-plaque agents, anti-bacterial agents, preservatives and effervescence generators.
Toothpaste and other oral cleansing products may be manufactured by conventional techniques. The alumina abrasives with which this invention is concerned are rather easy to incorporate for, unlike some other abrasive powders, they are generally not prone to lumping.
Here is an example of a toothpaste formulation:
Dicalcium phosphate 40% w/w
Alumina 10%
Sorbitol 25%
Polyethylene glycol 2%
Carboxymethylcellulose 1.1%
Sodium Saccharin 0.2%
Sodium Lauryl Sulphate 1.5%
Benzoic Acid 0.15%
Sodium Benzoate 0.2%
Water 19.5%
This formulation based on dicalcium phosphate polishing agent/filler, has been used to test the properties of various alumina abrasives. In the experimental section below, a different formulation based on a silica polishing agent/filler was used. Although the results obtained with the two formulations were different in absolute terms, they were generally the same in relative terms, i.e. any particular alumina abrasive generally had the same or a similar effect on the properties of both formulations. This justifies the assertion that an abrasive showing valuable properties in one toothpaste may reasonably be expected to show corresponding valuable properties in other oral cleansing products.
The alumina abrasives used in the experimental section below are either commercial products or development products (designated BAX). available from Alcan Chemicals Limited, and are here identified by means of their trade names. This invention is based on the discovery that the development product BAX842 has unexpectedly and outstandingly good properties.


Improved approaches for providing secure remote access to email resources maintained on private networks are disclosed. The secure access can be provided through a public network using a standard network browser. Multiple remote users are able to gain restricted and controlled access to email on a mail server within a private network through a common access point. The solution provided by the improved approaches allow not only native access to email resources but also robust authentication approaches.

1. Field of the Invention
The present invention relates to client-server computing and, more particularly, to client-server computing for securely accessing resources over a network.
2. Description of the Related Art
Network browsers (browser applications), such as Netscape Navigator or Microsoft Explorer, allow users of client machines to request and retrieve resources from remotely located server machines via the Internet. These network browsers can display or render HyperText Markup Language (HTML) documents provided by the remotely located server machines. Additionally, browsers are able to execute script programs embedded in the HTML documents to provide some local functionality.
Conventionally, network browsers are used to access public networks, such as the Internet. Private networks are normally protected by firewalls so that network browsers residing on computing machines outside the private network are not able to gain access to any resources on the private network.
While firewalls are effective at protecting against external access to private networks, there is often the need for external persons or businesses to gain at least limited access to the private networks of other persons or businesses. For example, a supplier of parts to a business customer may be able to better serve their business customer by having access to information (e.g., inventory levels or orders) maintained on the private network of the business customer. One conventional approach is to allow the supplier's machine to access the private network through the firewall via a public network. This provides a "hole" in the firewall that seriously compromises the security of the private network. Hence, this conventional approach is normally not permitted if security is an important concern. Another conventional approach is to establish a Virtual Private Network (VPN) with the supplier's machine. Here, the supplier's machine is also able to access the private network through the public network and the firewall, but all data transmissions are encrypted. Some firewalls support VPNs and protocols providing the encrypted communications, such as Point-to-Point Tunneling Protocol (PPTP), can be used. While VPNs offer remote secure access, they are difficult to arrange, configure and manage. Each VPN must also be provided for each external person or business given access to the private network. Still further VPNs are costly and each VPN provides some security exposure to the entire private network.
Thus, there is a need for improved approaches to providing secure remote access to resources maintained on private networks.


The field of the DISCLOSURE lies in active materials for organic image sensors. The present disclosure relates to naphthalene diimide-based molecules and naphthalene diimide dimer-based molecules. The present disclosure relates to transparent N materials and/or to transparent P materials including the molecule(s) according to the present disclosure and their use in absorption layer(s), photoelectric conversion layer(s) and/or an organic image sensor and methods for their synthesis. The present disclosure also relates to photoelectric conversion layer(s) including an active material according to the present disclosure, to a device, including active material(s) according to the present disclosure or photoelectric conversion layer(s) according to the present disclosure. Moreover, the present disclosure relates to an organic image sensor including photoelectric conversion layer(s) according to the present disclosure.

The field of the DISCLOSURE lies in active materials for organic image sensors.
The present disclosure relates to naphthalene diimide-based molecules and naphthalene diimide dimer-based molecules.
The present disclosure relates to transparent N materials and/or to transparent P materials including the molecule(s) according to the present disclosure and their use in absorption layers), photoelectric conversion layers) and/or an organic image sensor and methods for their synthesis.
The present disclosure also relates to photoelectric conversion layer(s) including an active material according to the present disclosure, to a device, including active material(s) according to the present disclosure or photoelectric conversion layer(s) according to the present disclosure.
Moreover, the present disclosure relates to an organic image sensor including photoelectric conversion layer(s) according to the present disclosure.

Specific N and P active materials for organic photoelectric conversion layers in organic photodiodes


The present invention relates to cleaning compositions which comprise the insect repellent ethyl 3-(N-butylacetamino)propionate and the use of this insect repellent in all types of cleaning compositions for repelling insects. This invention furthermore relates to a method for cleaning and for simultaneously repelling insects in which cleaning compositions comprising ethyl 3-(N-butylacetamino)propionate are used.

The invention relates to all types of cleaning compositions which comprise the insect repellent ethyl 3-(N-butylacetamino)propionate and are therefore used for cleaning and for simultaneously repelling insects from the surfaces and rooms to be cleaned.
In many respects, insects are a nuisance or even a threat to humans. In addition to the damage caused by some species of insects (for example the destruction of entire harvests), both humans and also many animals are troubled in one way or another, bitten and otherwise plagued by a wide range of insects. This can lead to infections and the transmission of dangerous diseases.
Insecticides are the main weapon in the fight against insects, but their use and toxicity profiles are not always without problems. These toxins often have undesirable effects on humans and animals, so that their use is limited or even banned.
However, measures such as the use of insecticides are not absolutely necessary to prevent the immediate nuisance. Some insects, such as, for example, cockroaches, in any case cannot be eradicated completely, and efforts are therefore increasingly directed more at repelling these insects than at destroying them.
Furthermore, protection of the environment is nowadays very much in the foreground, and preventive measures are therefore preferably taken.
Insect repellents are therefore now preferred to insecticides in combating insects, since the former are directed merely towards stopping insects from remaining and nesting on certain surfaces or in rooms.
Chemicals for repelling or destroying, for example, cockroaches, flies, mosquitoes or ants have been on the market for a long time, but many are dangerous to humans and animals or have a very unpleasant smell, so their adverse properties severely limit their use.
In view of the relatively small number of insect repellents which are not only effective but also acceptable from the toxicological aspect, great efforts to provide suitable products continue to be made in this field.
The object of the present invention was therefore to provide an insect repellent which effectively keeps away all types of insects, is easy to use and is toxicologically acceptable to humans and pets.
The substance ethyl 3-(N-butylacetamino)propionate is a proven insect repellent which has been known for a long time and is also employed as such in cosmetics formulations. It can be obtained commercially, for example from Merck KGaA, Darmstadt.
This substance, with its outstanding properties in respect of skin and mucosa tolerance without toxic, allergizing or sensitizing properties, has hitherto been used in cosmetics formulations in order to protect humans directly from attack by, for example, mosquitoes or flies.
This substance furthermore has a high chemical stability, i.e. it cannot be hydrolysed, cannot be photooxidized, cannot be oxidized and has a high heat stability.
Surprisingly, it has now been found that ethyl 3-(N-butylacetamino)propionate can also be incorporated into formulations of cleaning compositions of all types, and can therefore be used to drive off and keep away insects permanently from the surfaces cleaned with them, which can be hard or soft in nature.
It is known from the literature (U.S. Pat. No. 3,018,217), for example, to incorporate an insect repellent into a polishing composition for domestic floors, dibutyl succinate having been employed as the repellent. EP 0 525 893 also describes compositions for cleaning comprising various insect repellents, such as, for example, N,N-diethyl-m-toluamide (DEET). However, nowhere are cleaning compositions which comprise the abovementioned ethyl 3-(N-butylacetamino)propionate described.
In contrast to the prior art, the invention employs an insect repellent which has hitherto been used directly on humans, and the cleaning compositions according to the invention can thus be regarded as toxicologically acceptable and are therefore highly superior to the compositions known to date.
The term xe2x80x9cinsectxe2x80x9d is used here in the broadest sense and is intended to include, for example, common cockroaches (German cockroaches and also American roaches), fleas, flies, mosquitoes, ants, lice, ticks, bugs and even spiders.
The invention thus relates to a cleaning composition which is characterized in that it comprises an active amount, which is sufficient to repel insects after treatment with this cleaning composition, of the insect repellent ethyl 3-(N-butylacetamino)propionate.
The invention furthermore relates to the use of the insect repellent ethyl 3-(N-butylacetamino)propionate in cleaning compositions for repelling insects.
The invention furthermore relates to a process for cleaning and simultaneously repelling insects, which is characterized in that a cleaning composition comprising an active amount, which is sufficient to repel insects, of the insect repellent ethyl 3-(N-butylacetamino)propionate is used on the surfaces to be cleaned.
The cleaning compositions according to the invention preferably comprise 0.1 to 20% by weight of ethyl 3-(N-butylacetamino)propionate, particularly preferably 0.1 to 10% by weight, especially preferably 0.1 to 6% by weight.
The insect repellent of the present invention can be incorporated into all types of cleaning compositions, preferably into domestic cleaners. If appropriate, these domestic cleaners can additionally comprise, as well as the ethyl 3-(N-butylacetamino)propionate according to the invention, one or more insect repellents in each case in an amount of 0.1 to 20% by weight. These can be both synthetic substances, such as, for example, diethyltoluamide, 2-ethyl-1,3-hexanediol, dimethyl phthalate or dibutyl succinate, and also essential oils which are naturally occurring or identical to those in nature and act as insect repellents, such as, for example, menthol oil, citronella oil or lemon oil.
The insect repellent is preferably incorporated into solutions (aqueous or aqueous-alcoholic) or dispersions (or dispersed in a pulverulent carrier), into cleaning agent compositions such as detergents, floor or wall cleaners (tile cleaners), window cleaners, upholstery or carpet cleaners, also in shampoo form, into solid or liquid soaps, into wax, into creams or into sprays.
It can be incorporated into any other suitable formulation in which it could be of benefit, for example into insecticides or antibacterial compositions, furniture polishes or, floor waxes or else into compositions for cleaning certain hand tools which are used, for example, for animal husbandry or in horticulture.
The use of the cleaning compositions according to the invention causes insects to avoid contact with the cleaned surface after the hard or soft surfaces have been cleaned, since a film of this cleaning composition comprising the insect repellent has been formed as a result of the cleaning process.
The insects are additionally kept away from the area of the cleaned surface by the smell of this composition.
Thus, for example, ants, common cockroaches and other insects can be stopped from penetrating into storage rooms by cleaning shelves, walls and the floor with a cleaning composition according to the invention.
Cleaning upholstery or carpets with suitable shampoos can also stop the insects from nesting there and laying their eggs therein.
Detergents can furthermore prevent insects from entering linen cupboards and therefore into clothes.
From the above description, it is obvious that a wide range of compositions are possible for the cleaning agent according to the invention, and the cleaning compositions can be used for many different purposes.
However, the invention is preferably used in the field of domestic cleaners.
Such cleaners are composed of a large number of components.
For example, they comprise organic (soaps) or preferably synthetically organic surface-active, wash-active substances (surfactants), which can be anionic, amphoteric, ampholytic, zwitterionic, nonionic or cationic in nature, or else a mixture thereof. The anionic detergent bases are by far the most important here. Many such detergents are described in xe2x80x9cSurface Active Agents and Detergentxe2x80x9d, Volume II, by Schwartz, Perry and Berch (1958 Interscience Publishers, Inc.). However, the expert can also read about the most common surfactants in all the major reference works of chemistry (for example Rxc3x6mpp, Beilstein and the like).
The cleaners furthermore comprise builders and, if appropriate, bleaching agents, fragrances and auxiliaries.
Any detergent suitable for this purpose can be used as an anionic surfactant. Anion-based surfactants usually include, for example, fatty alcohol sulfates, paraffinsulfonates, fatty acid condensation products and alkylbenzenesulfonates and -phosphonates, and also alkyl sulfates and phosphates. The anionic surfactants are preferably sodium salts, but potassium, ammonium and triethanolammonium salts are also often employed in some liquid compositions. The alkyl radicals are preferably straight-chain and preferably have 12 to 16 carbon atoms.
Synergistic combinations, primarily with fatty alcohol polyglycol ethers, have proved suitable as the base for many compositions.
Suitable nonionic raw materials are condensation products of lipophilic components and lower alkylene oxides or polyalkyleneoxy units. The fatty alcohol polyglycol ethers mentioned, the alkylphenol polyglycol ethers or else fatty acid alkylamides, for example, are preferably employed.
Cationic surfactants can also be used, for example aliphatic quaternary ammonium salts.
The substances known as builders are also generally known and can be inorganic or organic in nature and water-soluble or insoluble. Substances such as polyphosphates, for example pentasodium triphosphate, carbonates or bicarbonates, for example sodium carbonate or sodium bicarbonate, zeolites, for example zeolite A, polycarboxylates, for example sodium salts of copolymers of acrylic acid and maleic acid, and also borates and silicates, for example laminar sodium silicate, are preferred.
Further auxiliaries or additives which can be added are fragrances and dyestuffs, bleaching agents or brighteners, antistatic agents, antibacterial agents, fungicides, foam-forming reagents and also anti-foaming substances, antioxidants and enzymes.
The abovementioned substances for composing cleaning compositions are intended to be examples and have no limiting character for the formulations according to the invention.
All the substances known in the prior art which are described for formulating such cleaning compositions can be mixed according to the invention with ethyl 3-(N-butylacetamino)propionate.
The cleaning compositions according to the invention can be present in solid form, as a powder, as tablets, in block or piece form, as a paste, as a gel, in liquid form, as a wax, as a cream, as an emulsion, as a dispersion, as a foam or as a spray (aerosol form) or as other suitable forms appropriate for the particular use.
The quantitative composition of the individual components for the various formulation possibilities is well-known to the expert in this field and does not have to be listed here in more detail.
According to the invention, the content of ethyl 3-(N-butylacetamino)propionate in the particular formulations is 0.1 to 20% by weight, preferably 0.1 to 10% by weight, especially preferably 0.1 to 6% by weight.
The cleaning compositions according to the invention are preferably present as an aqueous or aqueous-alcoholic solution, as a detergent, as a wax, as a gel, as an emulsion, as a cream, as a shampoo, as a spray, as a dispersion or as a solid product.
The methods for the preparation of such products are generally known to the expert in the field of preparation of soaps and detergents and do not have to be explained in more detail here.
To prepare an aqueous or aqueous-alcoholic solution, the insect repellent is preferably dissolved in a suitable solvent, such as water (which usually means demineralized water), lower alcohols, such as, for example, ethanol, or mixtures thereof. These mixtures can of course also additionally comprise other substances, such as, for example, esters, aldehydes, ketones, hydrocarbons and also halogenated hydrocarbons. Examples of the latter which may be mentioned are isobutane, dichlorodifluoromethane, monofluorotrichloromethane and other chlorinated and/or fluorinated methanes, ethanes or propanes. Such substances include those liquefiable gases which remain in the liquid state in pressurized containers ready for use as sprays.
Particularly preferred cleaning compositions of this invention comprise, as a synthetic organic surfactant, an anionic or nonionic surfactant, or mixtures thereof, builders and/or fillers and the insect repellent.
These cleaning compositions or detergents can be present in particle form or in liquid form. The liquid form comprises the same individual components, but in addition a liquid medium, and if appropriate also emulsifying substances and other auxiliaries.
Preferred shampoos for cleaning upholstery or carpets also comprise water-soluble soaps and synthetic wash-active substances, builder salts, the insect repellents, and usually water as the liquid medium. Such shampoos can also be formulated as a gel or in paste or powder form.
Solid products according to the invention in block, tablet or piece form (bars of soap), which can be used for cleaning laundry, carpets and/or hard surfaces, such as, for example, floors and walls, can also be prepared.
In all these formulations, the ratios of soaps or synthetic organic surfactants, builders and auxiliaries to insect repellent are similar and can be varied within wide ranges. Preferably, the formulations comprise 1 to 40% of surfactants or soaps, 10 to 90% of builders and fillers and 0.1 to 20% of ethyl 3-(N-butylacetamino)propionate (figures in % by weight). Water, alcohols, auxiliaries and/or emulsifying substances are usually added for completion (to 100% by weight).
The various cleaning compositions described can be prepared by methods known to the expert. Such processes include spray drying, dry mixing, dissolving and/or dispersing and/or emulsifying, grinding or alternatively pressing.
When the cleaning compositions according to the invention are applied by spraying, wiping, rubbing or other methods to the surfaces to be cleaned, the insect repellent which they comprise is deposited on these surfaces in a sufficiently high concentration or amount to act as a repellent against insects.
Particularly preferred cleaning compositions of this invention are those in liquid form.
The following formulations, which are used as general-purpose cleaners, are especially preferred embodiments according to the invention.
Amphoteric surfactants, for example those based on cocamidoalkylbetaine, alone or mixed with anionic, cationic and nonionic surfactants, are preferably employed in these general-purpose cleaners. Neutral formulations as well as alkaline or acidic compositions can be prepared with these.
Salt-free capryl iminodipropionate is preferably employed as a further amphoteric surfactant for use in highly alkaline or strongly acidic formulations.
Further particularly preferred surfactant groups are the amine oxides and the alkyl poly-glucosides, which are particularly readily mixed with betaines and lauryl ether sulfates.
General-purpose cleaners can be employed universally, as the name implies. They are usually neutral to slightly alkaline formulations.
Formulations according to the invention of this type with antibacterial additives are also particularly preferred.
The cleaning compositions according to the invention have a particularly good action against ants and common cockroaches.
With the cleaning compositions of the present invention, the consumer thus has available essentially non-toxic and therefore highly environment-friendly but nevertheless highly active products.
By using the cleaning compositions according to the invention and the process according to the invention, it has been possible to demonstrate in practice that, for example, significantly fewer cockroaches were to be found behind cupboards or under refrigerators compared with beforehand.
If floors, walls, sinks, doors or cupboards in a house or flat are therefore treated regularly with the cleaning compositions according to the invention, the incidence of insects, in particular cockroaches or ants, is reduced practically to zero.
Without further embodiments, it is also assumed that an expert can use the above description in the broadest scope. The preferred embodiments are therefore to be interpreted merely as a descriptive and not in any way as a limiting disclosure.
The complete disclosure of all the Applications, Patents and publications mentioned above and below is introduced into this Application by reference.
The following examples are intended to illustrate the invention.


A phase change memory includes a memory element and a selection element. The memory element is embedded in a dielectric and includes a resistive element having at least one sublithographic dimension and a storage region in contact with the resistive element. The selection element includes a chalcogenic material embedded in a dielectric. The chalcogenic material and the storage region are part of a stack having a common etched edge.

The present invention relates to a phase change memory.
Phase change memories use a class of materials that have the property of switching between two phases having distinct electrical characteristics, associated to two different crystallographic structures of the material, and precisely an amorphous, disordered phase and a crystalline or polycrystalline, ordered phase. The two phases are hence associated to resistivities of considerably different values.
Currently, the alloys of elements of group VI of the periodic table, such as Te or Se, referred to as chalcogenides or chalcogenic materials, can be used advantageously in phase change memory cells. The currently most promising chalcogenide is formed from an alloy of Ge, Sb and Te (Ge2Sb2Te5).
In the chalcogenides, the resistivity may vary by two or more orders of magnitude when the material passes from the amorphous (more resistive) phase to the crystalline (more conductive) phase, and vice versa.
Phase change can be obtained by locally increasing the temperature. Below 150° C., both the phases are relatively stable, with an amorphous bit tending to gradually crystallize over a period of years if held at 150° C. Starting from an amorphous state, and raising the temperature above 200° C., where there is a rapid nucleation of the crystallites and, if the material is kept at the crystallization temperature for a sufficiently long time, it undergoes a phase change and becomes crystalline. Preferably, the material is cooled off slowly to better assure the crystalline state. To bring the chalcogenide back to the amorphous state it is necessary to raise the temperature above the melting temperature (approximately 600° C.) and then rapidly cool off the chalcogenide.

Phase change memory with ovonic threshold switch


A composite cable unit having an optical sub-unit including at least one optical fiber, and an electrical sub-unit including at least one electrical conductor for power or transmission. The optical and electrical sub-units are removably connected together by a common jacket material. The composite cable unit can be used singly or in, for example, fan-out or break-out cables.

The present invention relates to composite cables having combined optical and electrical power and/or transmission capabilities.
Conventional fiber optic cables include optical fibers that conduct light which is used to transmit voice, video, and data information. Conventional composite cables combine the advantages of optical transmission components, e.g., large bandwidth and low power loss, with the advantages of electronic/electrical transmission components which include low cost and straightforward termination procedures. Typical applications for composite cables include fiber-to-the-curb (FTTC), fiber-to-the-home (FTTH), fiber-to-the-desk (FTTD), plenum, riser, and local area networks (LANs). In a premises environment, composite cables can be used to interconnect hardware, for example, computers and telephones.
A conventional cable design is illustrative of transmission electrical cables. U.S. Pat. No. 5,681,179 discloses a conventional electrical zip cord with stranded electrical conductors only. The zip cord can be terminated with an electrical connector with relative ease, but the cable does not include optical transmission components.
Conventional composite cables can include a row of optical fibers and a separate row of electrical conductors. For example, U.S. Pat. No. 5,039,195 discloses a composite cable with two distinct cable units. A first cable unit includes optical fiber sub-units connected to strength members by a common jacket having interconnecting web sections. A second cable unit includes metal conductors connected by a common jacket having interconnecting web sections. Both cable units are surrounded by a cable jacket.
As disclosed in U.S. Pat. No. 5,602,953, a composite cable can include a combination of loose-buffered optical fibers and electrical conductors in a common jacket. The common jacket defines a flat structure including box-shaped sub-units, apparently formed by an injection molding process, with twisted electrical leads and optical fibers disposed in buffer tubes. The cable is designed to be separated into the box-shaped sub-units.
It is an object of the present invention to provide a composite cable unit having an optical sub-unit including at least one optical fiber, and an electrical sub-unit including at least one electrical conductor. The optical and electrical sub-units are removably connected together by a common jacket material.
It is an object of the present invention to provide a fan-out cable having a central member with cable units therearound. At least one of the cable units comprises a composite cable unit, the composite cable unit including an optical sub-unit with at least one optical fiber, and an electrical sub-unit including at least one electrical conductor, the optical and electrical sub-units being removably connected together by a common jacket material.