WO2000031199A9 - A pressure-sensitive adhesive laminate, a method and a device for modifying an initial release force in such a laminate - Google Patents
A pressure-sensitive adhesive laminate, a method and a device for modifying an initial release force in such a laminateInfo
- Publication number
- WO2000031199A9 WO2000031199A9 PCT/BE1999/000151 BE9900151W WO0031199A9 WO 2000031199 A9 WO2000031199 A9 WO 2000031199A9 BE 9900151 W BE9900151 W BE 9900151W WO 0031199 A9 WO0031199 A9 WO 0031199A9
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- radiation
- laminate
- release
- release layer
- adhesive layer
- Prior art date
Links
Classifications
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J7/00—Adhesives in the form of films or foils
- C09J7/40—Adhesives in the form of films or foils characterised by release liners
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J7/00—Adhesives in the form of films or foils
- C09J7/10—Adhesives in the form of films or foils without carriers
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J2301/00—Additional features of adhesives in the form of films or foils
- C09J2301/40—Additional features of adhesives in the form of films or foils characterized by the presence of essential components
- C09J2301/416—Additional features of adhesives in the form of films or foils characterized by the presence of essential components use of irradiation
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J2475/00—Presence of polyurethane
- C09J2475/005—Presence of polyurethane in the release coating
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J2483/00—Presence of polysiloxane
- C09J2483/005—Presence of polysiloxane in the release coating
Definitions
- the invention relates to a pressure-sensitive adhesive 5 laminate comprising an adhesive layer and a release layer contacting each other.
- PSA laminates are well-known in the art and commonly used as tapes, decals labels and the like. PSA laminates made with radiation-curable silicones are described in the
- a drawback of the known PSA laminates is that once the initial release force is set, the latter can not be changed at a later stage.
- a PSA laminate comprising a release layer and an adhesive layer contacting each other
- said PSA laminate being characterised in that said adhesive layer comprises a first compound that is reactive on application of an ionising radiation or an actinic radiation, in order to modify an initial release force between said adhesive layer and said release layer.
- the addition of the first compound in the adhesive layer enables to obtain a laminate that can be irradiated after manufacturing in order to modify the initial release force.
- the use of a reactive compound in the release layer not only enables to modify the release force between the release layer and the adhesive layer, but also between the carrier and the release layer. In such a manner, the adhesiveness of the laminate can be modified by modifying the release force at one or both interfaces of the release layer .
- the reactive compound is chosen among : free radical initiators, cationic initiators, acetophenone and derivatives, benzophenone and derivatives, benzoin and derivatives, quinone and derivatives, xanthones, acridones, titanocenes, polymer-bound photoinitiators, dye/coinitiator systems, 4,4'-bis(N,N-di-n-butylamino)-E- stilbene, biphotonic photoinitiators, acetylacetonate of Co or Cr or Mn, organometallic compounds based on at least one element of the groups 4,5,6,7,8 or 10; or a mixture of them.
- free radical initiators cationic initiators
- acetophenone and derivatives acetophenone and derivatives
- benzophenone and derivatives benzoin and derivatives
- quinone and derivatives quinone and derivatives
- xanthones acridones
- titanocenes polymer-bound
- the invention also relates to a method for modifying an initial release force between an adhesive layer and a release layer of a pressure-sensitive adhesive laminate, wherein the adhesive layer comprises a first reactive compound, having first predetermined reactive properties.
- the method according to the invention is characterised in that a final release force to be obtained between said adhesive layer and said release layer is set, and in that a radiation dose is determined on the basis of the final release force and the reactive properties of the first compound, said radiation dose being then applied on said laminate by means of an ionising radiation or an actinic radiation.
- the pressure-sensitive adhesive laminate according to the invention enables to modify the initial release force, the requested final release force can be set in function of the client's requirements. Once the final release force is set, and taking the reactive properties of the used compound into account, the radiation dose requested to obtain that final release force can be determined. After determination of this dose, the laminate is irradiated in accordance with that dose.
- the compound will react in order to modify the release force between the adhesive layer and the release layer, between the release layer and the carrier, or both. As the dose is determined, the requested final release force will be obtained.
- a predetermined segment of the pressure-sensitive adhesive laminate is masked in order to prevent said radiation to reach the masked segment of the laminate.
- the release force can be modified only in the unmasked segments of the laminate. This is for example of interest for laminates where only a segment of the front layer, for example that segment containing a particular item, has to be removed. By changing the release force of the latter, the delamination force is modified in order to make delamination easier.
- a topography of locations of the laminate to be irradiated is determined, and a radiation is applied on said locations.
- At least one segment of said laminate is selected and for said segment a radiation gradient is determined, said radiation dose being applied on said segment according to said radiation gradient.
- the front layer of a pressure-sensitive adhesive according to the invention can be formed by an image carrier on which an image field can be printed.
- an image of the product is printed on the front layer.
- the method according to the present invention provides an elegant solution.
- the method is characterised in that a cutting is applied along a border line and in that a final release force, to be obtained between said layers, is determined for at least one of the fields, in function of said predetermined third reactive properties, a radiation dose being determined on the basis of the final release force, said radiation dose being applied on said field for which said radiation dose was determined, by means of an ionising radiation or an actinic radiation.
- the image field is dissociated from the rest of the image carrier.
- the application of a radiation on either the image field or the non-image field, or even on both, provided in the latter case the dose is different, will modify the release force in the irradiated field(s) so as to enable an easier removal of the image or non-image field.
- an adhesive sheet is applied on the side on which the borderline was cut.
- the use of an adhesive sheet, also called transfer film, facilitates the removal of the image or non-image field.
- the present invention further relates to a device for the application of the method described herein before.
- said device comprises a radiation source provided for emitting an actinic radiation or an ionising radiation onto said laminate and is characterised in that it further comprises a cutting tool having an input for supplying a predetermined cutting profile and comprising a first transport member provided for moving said cutting tool along said profile over said laminate, said radiation source having a further input for receiving a predetermined value indicating a radiation dose to be applied, and said radiation source being mounted on a second transport member provided for moving a radiation beam emitted by said source over a predetermined area of said laminate to be irradiated.
- a further problem of pressure-sensitive adhesive laminates that is solved by the present invention, is the bleeding of the adhesive layer. Bleeding signifies that the adhesive substance, present in the adhesive layer, shows a tendency to flow towards the edges of the laminate. In particular when the laminates are stacked or wound into a roll, the pressure applied on the adhesive layer due to stacking can make the adhesive substance flow.
- the method of the present invention is characterised in that a radiation dose for increasing the initial release force between said adhesive and said release layer is determined and thereafter said dose is applied on said edge by means of an actinic radiation or an ionising radiation.
- the release force between the adhesive layer and the release layer is increased, causing the adhesive substance to better stick to the release layer at the edges and thus decreasing the bleeding.
- the adhesive layer comprises a compound reactive upon irradiation, that adhesive layer could also be hardened by irradiation.
- the present invention proposes a method wherein a radiation dose for increasing the release force between said adhesive and said release layer is determined and thereafter said dose is applied on at least two edges of the laminate by means of an actinic or ionising radiation.
- the release force between the adhesive layer and the release layer is increased, and thus the release force between the front sheet and the carrier is increased at those edges, causing a stronger binding between the front sheet and the carrier and thus decreasing the shrinkage of the front sheet.
- Delamination is often mechanically realised, for instance in order to apply labels onto objects. A problem that occurs during mechanical delamination is that the release force is too high on the impact border, which is the border at which delamination is initiated. Reducing the overall release force is not an appropriate solution as this would cause an insufficient adhesion.
- the solution provided by the present invention is characterised in that an ionising or actinic radiation dose is applied before delamination on said impact border and/or on a further border opposite to said impact border for modifying the release force on said irradiated border.
- an ionising or actinic radiation dose is applied before delamination on said impact border and/or on a further border opposite to said impact border for modifying the release force on said irradiated border.
- the invention also relates to a device for applying on an object a label which is part of a pressure-sensitive laminate comprising an adhesive layer and a release layer contacting each other, wherein a side of said release layer opposite to the one contacting said adhesive layer is applied on a carrier, and wherein a side of said adhesive layer opposite to the one contacting said release layer is applied on a front sheet, said device comprising a supply station provided for supplying said labels, said device further comprising a delamination station downstream of said supply station and provided for delaminating said labels.
- Such a device is characterised in that said delamination station comprises a first selection unit provided for selecting among said supplied labels a first series of labels which have to be delaminated, and in that said device also comprises a radiation station coupled to a second selection unit provided for selecting among said supplied labels a second series of labels which have to be at least partially irradiated, said radiation station being provided for applying a radiation dose on said second series of labels.
- the invention further provides a solution for modifying an adhesiveness of a pressure-sensitive laminate.
- a method according to the invention is characterised in that at least one segment of said laminate wherein said adhesiveness has to be modified is determined, said segment being divided in a first set and second set of mutually exclusive fields, a radiation dose being determined on the basis of the reactive properties of the third reactive compound and the adhesiveness value to be obtained, said radiation dose being applied by means of an actinic or an ionising radiation on the fields for which the adhesiveness value is determined.
- figure 1 shows a cross-section through a pressure-sensitive adhesive laminate according to the invention
- figure 2 illustrates the method and the device for irradiating a laminate according to the invention
- figure 3, 4 and 5 show schematically the effect of an irradiation of a laminate
- figure 6 shows examples of laminates where only segments are irradiated
- figure 7 shows schematically a device for automatically selecting and delaminating labels.
- FIG. 1 shows a cross-section through an elementary embodiment of a pressure-sensitive adhesive (PSA) laminate 1 according to the present invention.
- the laminate comprises a carrier 2 generally made of paper or plastic on which a release layer 3 is applied. A first side or underside of the release layer 3 is in contact with the carrier, whereas a second opposite side or upper-side is in contact with an adhesive layer 4.
- a front layer or front sheet 5 contacts the upper side of the adhesive layer 4.
- the front layer is also made for example of paper or plastic and can be used as an image carrier when an image has to be printed on the PSA laminate.
- FIG 1 only one adhesive and only one release layer are shown. However several adhesive and release layers can be provided and the layers can be of different compositions depending on the required properties. So, for example the adhesive layer could be sandwiched between two release layers.
- the release layer preferably comprises a substance chosen among silicone, acrylated silicone, silicone comprising ethylenically unsaturated groups, urethane, polysilane, polysilylether or polyphtalaldehyde.
- the release layer can be heat-curable or radiation- curable.
- the pressure-sensitive adhesive layer comprises for instance an acrylic- or rubber-based polymer.
- a first compound is added to the adhesive layer and a second compound is added to the release layer. It is however not necessary to add the compound to each layer and the addition of a single compound to either the adhesive or the release layer could be sufficient for application of the present invention. Generally spoken, one could consider that at least one third compound is added to at least one of the adhesive or release layers.
- the adhesive layer comprises a first reactive compound and the release layer a second reactive compound. The compound is reactive on application of an ionising radiation and/or an actinic radiation.
- the ionising radiation can be formed by a beam of electrons, of neutrons or of other physical particles whereas the actinic radiation can be formed by a light or photon beam comprising either a well defined wavelength or a range of wavelength for example between 100 nm and 1000 nm, preferably between 150 nm and 750 nm.
- the purpose of adding a compound in the release and/or adhesive layer is to be able to modify the initial release force after manufacturing the PSA laminate.
- the present invention proposes to add during manufacturing a compound that is reactive to ionising or actinic radiation. In such a manner, the initial release force can be changed, in a controlled manner, after manufacturing of the PSA laminate, by irradiation with a suitable radiation dose.
- the radiation applied on the PSA laminate to which the compound was added will modify the initial release force at one or more layers, because it will modify the physical and/or chemical interactions of that or those layers which comprise the reactive compound.
- the result will be either an increased or a decreased release force.
- the release force is defined as the force, expressed in Newton, required for separating the carrier with the release layer from the adhesive front sheet according to a predetermined angle of 180° and at a predetermined separation speed, such as set forth by the FINAT method (see for example Technical Manual FINAT, 4 th edition 1995 and published by FINAT, LAAN COPES VAN CATTENBURCH 74, NL - 2585 EW THE HAGUE).
- the release force is measured by separating the release layer from the adhesive layer, although in some cases in the present invention, the release force is measured by separating the release layer from the carrier.
- the degree at which the release force will be changed will depend on the radiation dose and on the reactive properties of the compound, and generally also on the composition of the layer(s) contacting the radiation-activable layer.
- a radiation dose has to be determined taking into account the set final release force and the reactive properties of the reactive compound used. Once the radiation dose is applied, the final release force will remain stable.
- an adhesive which has radiation- sensitive properties could also be considered, i.e. an adhesive or release layer which already has a reactive compound in its composition.
- an adhesive or release layer which already has a reactive compound in its composition.
- the adhesive Acronal 3429 and 3458 of BASF have such properties.
- the viscosity of the adhesive is reduced whereas the elasticity is increased by ultraviolet irradiation.
- the irradiation causes the chemical and/or physical bondings between the polymer chains to modify and to harden or soften the adhesive, depending on the radiation and the substance used.
- Figure 2 illustrates schematically a device and a method according to the invention.
- the device comprises one or two radiation sources 9, 10, of which one (10) is placed under the laminate 1 and the other one above the laminate.
- the radiation beam emitted by the source can be oriented by means of a transport member, for example adjustable mirrors in the case of actinic radiation or magnetic and/or electrical fields in the case of ionising radiation.
- the transport member is preferably controlled by a computer 11 in order to accurately control the movement of the beam.
- the computer 11 is further connected to an input unit 12, for example a keyboard enabling the user to enter data such as the set final release force and the characteristics of the compound present in the adhesive and/or release layer.
- the computer 11 is preferably charged with a program suitable to calculate the radiation dose based on the set final release force and the reactive properties.
- the computer is further programmed to control the radiation once the dose has been calculated.
- the beam of radiation is usually normal to the surface of the PSA laminate. However for particular applications, such as for instance for irradiating the edges of the laminate in order to decrease the bleeding of the adhesive or the shrinkage of the front layer, as will be described hereinafter, the beam will be oriented in parallel to the layers of the laminate.
- the beam can also be inclined under an angle of less than 90°, if for example only a segment has to be irradiated.
- the radiation is preferably applied on a laminate that is supplied by a roll 7 and wound on a further roll 8 after irradiation.
- the side that is irradiated has to be at least partially transparent for the applied radiation in such a manner that the beam reaches the activable layer(s) to be irradiated.
- the radiation can be applied over the whole surface of the layer to be irradiated or only on one or more segments of the surface depending on the locations at which the release force has to be modified.
- the intended use of the laminate will determine which locations have to be irradiated.
- Figure 3 shows an example where the PSA laminate is formed by a series of labels 1-a, 1-b, 1-c and 1-d. Only the borders of two subsequent labels are irradiated as indicated by the shade on the labels. In that figure the front or the back border are irradiated. It is however also possible to irradiate both the front and the back border, or to irradiate both borders with a different dose in order to obtain a different release force between the font and the back edge.
- the latter application is for example advantageous for a mechanical application of labels on products.
- the front side or impact border needs a weak release force in order to easily initiate the delamination, whereas the back side needs a stronger release force in order to avoid that the label would insufficiently adhere to the release layer.
- Another application of the label pictured in figure 3 is the ability to delaminate and to apply selectively label 1-a and 1-b when the band is going from the left to the right and to apply selectively the labels 1 -c and 1 -d when the band is going from the right to the left, because the labels are not easily delaminated when the release force at their impact border is high.
- Figure 4a + 4c show an example where the radiation is only applied on a central part c of the laminate so that upon delamination a part 3-c of the release layer remains adhered to the adhesive layer 4.
- a different dose is applied on the part c with respect to the parts a an b, so that in part c the adhesive layer 4 remains adhered to the release layer 3, whereas in part a and b, the adhesive layer remains adhered to the front layer 5.
- Figure 5a + 5b show a self-wound laminate with adhesive layers 4 and 4' and release layers 3 and 3'.
- a radiation dose A is applied on the parts d and b, whereas on the parts a, c and f, a radiation dose B is applied.
- the adhesiveness of the laminate at the top and bottom external surfaces can thus be changed in mutual exclusive fields of the laminate by application of a radiation dose.
- the active ionising or actinic radiation that can be used for the modification of the release force can be chosen in the following, non- limitative list : electron beam, neutrons, x-rays, gamma rays, beta rays, alpha particles, electron corona discharge, actinic light.
- the actinic light can be provided for instance by mercury lamp, xenon lamp, deuterium lamp, pulsed lamp, excimer laser, excimer lamp, microwave driven lamps, laser or pulsed laser.
- the ultraviolet wavelength range is considered to be between 200 nm and 400 nm.
- a release layer, nearly one micron thick, of a silicone mixture of Tego RC 726, 70 parts and Tego RC 750, 30 parts (Th. Goldschmidt AG, Essen, Germany, in parts by weight) is applied onto a 50-micron BOPP transparent carrier film.
- the silicone layer Under a nitrogen blanketing, with less than 50 ppm oxygen in the irradiation zone, the silicone layer is cured, at a speed of 100m/min, by irradiating the siliconised BOPP with ultraviolet light emitted by two medium-pressure mercury lamps ( 2x 80W/cm) with reflectors.
- An adhesive layer of Acronal V210 ( BASF, Ludwigshafen, Germany) is applied onto the silicone layer and dried in a thermal oven.
- the coating weight of adhesive after drying is 20g/m 2 .
- a 100-microns polyethylene film is applied onto the adhesive layer.
- the release force increases as shown in the following table.
- the speed of the samples under the UV lamp is 20 m/min, the power of the lamp is 80 W/cm, the lamp is a medium-pressure mercury lamp, parallel to the sample and perpendicular to the transport direction of the laminate.
- the samples were irradiated 1,2,3,4, or 5 times successively, the UV light being applied onto the BOPP.
- the release values of the samples are given in the table, measured just after UV irradiation and after six-months storage in the dark.
- FTM 4 speed 80 m/min all values are in N/ 25mm.
- the release layer is for example made of the following products :
- Tego 450, Tego 711 , Tego 726 and Tego 750 are products from Th. Goldschmidt AG, Essen, Germany.
- Darocur 1173 is from Ciba Specialities.
- BDBS is 4,4'-bis(N,N-di-n-butylamino)-E-stilbene
- Tego 726 Tego 711 : Darocur 1173 of about 70:30:2.
- Formula 2 A mixture of Tego 726 : Tego 711 : Darocur 1173 of about 70:30:2.
- Tego 726 Tego 711 : Darocur 1173 : BDBS of about 70:30:2:1.
- Tego 450 Tego 726 : Tego 711 : Darocur 1173 : BDBS of about 30:30:20:2:1.
- each formula is coated on a 50-microns BOPP film which serves as carrier.
- Each coated siliconised liner is cured with ultraviolet light under nitrogen (less than 50 ppm oxygen) at 50 m/min, the power of the medium-pressure mercury lamps being 80 W/cm.
- An adhesive made of about 82.5 weight percent Acronal V 205 (BASF) and about 17.5 weight percent Snowtack 352 A (Akzo-Nobel ) is then coated on the siliconised BOPP and dried in a thermal oven in order to form the adhesive layer. The coated weight of dried adhesive is about 20 g/m 2 .
- a 100-micron polyethylene film is then applied on the adhesive layer.
- the laminates are stored for one month, in absence of light, before subsequent irradiations.
- the pressure-sensitive laminates formed with the silicones formulas 1 to 6 are called laminates 1 to 6.
- the initial release force (test FTM 3) is between about 0.1 N/25mm and 0.3 N/25 mm for the laminates 1 to 6.
- a high-tack silicone tape is applied on the siliconised side of the BOPP, for each of the sample 1 to 6, and the laminates are stored for one week. The release force between the BOPP and the silicone release layer is then measured for the 6 samples.
- One sample of each of the six laminates (laminates 1 to 6) is irradiated with ultraviolet light on the 50-micron BOPP liner, by applying a 1 W/cm 2 or 5 W/cm 2 dose, with a medium-pressure mercury lamp. After irradiation, the release force (FTM3) of the laminates is increased by more than 20 % for each sample and each dose, compared to the values before ultraviolet irradiation.
- One sample of each of the six laminates is irradiated with a pulsed laser (600 nm) on the 50-micron BOPP liner.
- the global irradiation dose is around 1 W/cm 2 or 5 W/cm 2 .
- the release force ( FTM 3) of the laminates is increased by more than 20 % for each sample and each dose, compared to the values before laser irradiation.
- Another series of samples of the laminates 1 to 6 is delaminated, and the silicone side of their UV-cured liner is applied on the adhesive side of a tape bearing a high-tack silicone pressure-sensitive adhesive, in order to measure the release force between the 50-micron BOPP and the cured silicone. After 10 days, the tape is separated from the liner, dragging off the silicone release layer. The release force between the UV-cured silicone layer and the BOPP liner is measured by cleavage at the interface between the BOPP carrier and the UV-cured release layer.
- the release force of the laminate is measured. After delamination, the release layer stays anchored on the adhesive layer.
- the release value measured between the silicone layer and the BOPP is increased by more than 20 % compared to the value before irradiation.
- Irradiation by visible light One sample of each of the six laminates is irradiated with a pulsed laser (600 nm) on the 50-micron BOPP liner.
- the global irradiation dose is around 1 W/cm 2 or 10 W/cm 2 .
- the release value measured between the silicone layer and the BOPP is increased by more than 20 % compared to the value before laser irradiation.
- One sample of each of the six laminates is irradiated with an electron beam, on the BOPP film, with a 1-Mrad dose or a 10-Mrad dose (200 KeV).
- the release value measured between the silicone layer and the BOPP is increased by more than 20 %, compared to the values before electron irradiation.
- the release force and/or the adhesive properties of the PSA laminates can be modified in selected areas and to a selected level, by irradiation of the PSA laminate with a selected type and dose of actinic or ionising radiation.
- the radiation can modify the interactions between an adhesive layer and a release layer and/or the interactions between a carrier and a release layer.
- the whole zone can be irradiated, or only specific areas in the zone can be irradiated, in order to modify the average release properties.
- the PSA laminate is irradiated on selected areas with a specific dose and type of irradiation.
- the anchorage of the release layer on the adhesive layer is higher than the anchorage of the release layer on the carrier in the irradiated areas, but lower in the non-irradiated areas, and, during the removal of the release liner, the release layer is transferred onto the adhesive layer on the areas that were irradiated.
- the percentage of the adhesive surface covered with a release layer after removal of the release liner is generally directly related to the decrease of adhesiveness (FTM1 and FTM9 values) of the adhesive layer.
- An aluminium (thickness 0.5 mm) mask with a gradient of holes (5 x10 mm) is applied on the BOPP liner of the PSA laminates.
- a dose of ultraviolet light about 1 W/cm 2 or about 10 W/cm 2 , is applied on the BOPP liner of the laminates, through the aluminium mask.
- the laminates are cut into stripes (25 mm width), the BOPP liner is removed, and the adhesive side of the stripes of laminates are applied on glass plates, in order to measure the adhesive properties.
- the anchorage of the release liner is higher on the adhesive than on the BOPP liner.
- the adhesive surface of the PSA laminate is partially covered with a silicone layer in the zones that were partially masked, the adhesive surface is totally covered with the release layer in the zones that were totally irradiated, and the adhesive surface is free of silicone in the areas that were not irradiated.
- the adhesive properties of the laminate are roughly proportional to the surface of adhesive that is not covered with the silicone release layer.
- the release layer is not pressure-sensitive.
- the release layer, based on silicone is a pressure-sensitive adhesive
- the layer contacting said release layer is a pressure-sensitive adhesive based on an acrylic polymer.
- the laminate is irradiated through a mask, in the same way as that described previously in example 3.
- the adhesion properties are those of the acrylic adhesive in the areas that are free of silicone, are substantially equivalent to those of the silicone in the zones totally covered with the release layer, and are comprised between the properties of the acrylic adhesive and those of the (adhesive) silicone in the adhesives zones that are partially covered with the release layer.
- the silicone-based pressure-sensitive adhesives have high adhesion at low temperatures, or when applied onto substrates having low surface tension, however their price is much higher than that of acrylic- or rubber-based adhesives.
- a PSA laminate having a PSA layer partially or totally covered with a pressure-sensitive adhesive silicone release layer can be obtained with the method described in the present invention.
- This PSA laminate has new and interesting properties, that are intermediate between the properties of the adhesive and the properties of the pressure-sensitive adhesive release layer: good adhesion at low temperatures, good adhesion on low-surface-tension substrates and a cost much lower than that of a purely silicone-based adhesive.
- the acrylic pressure-sensitive adhesive of the laminate can be replaced by a rubber-based adhesive or an adhesive based on another polymer.
- the method described for increasing the release force can be adapted for decreasing the release force.
- a compound that is depolymerised by radiation can be incorporated in the release layer, and treated similarly as described previously.
- Such compounds can be selected among: polysilanes, polyphtalaldehydes, silicones containing silylether groups or tertiary polycarbonates groups in the main chain, silicones, cationic initiators, or a mixture of them.
- Figure 6 shows examples of labels made of a PSA laminate where only segments of some labels, indicated by shade, are irradiated.
- the device is provided with a mask-carrier member provided to carry the mask.
- the mask-carrier member is placed in the path of the radiation beam in order to prevent the beam from reaching the masked segments.
- That topography is for example formed by sets of co-ordinates identifying the location on the laminate. That set is then entered into the computer, which will control the radiation beam in such a manner that only the predetermined locations are irradiated.
- the release force and/or adhesiveness is modified in the irradiated segments.
- the release force between the release layer and the adhesive layer is increased to a level higher than the release force between the release layer and the carrier in a specific segment, the release layer will remain on the adhesive after delamination, thus modifying the adhesiveness of the PSA laminate. A gradient of adhesiveness on a segment can thus be obtained.
- Another problem is the printing and delamination of pressure-sensitive labels applied on a carrier roll.
- the release force at the front edge of the labels When a roll of pressure-sensitive laminate bearing die-cut labels is printed, the release force at the front edge of the labels must be sufficiently high in order not to have delamination of some labels in the printing machine. However, when the labels are subsequently delaminated, the release force at the front edge of the labels must be low in order to have an easy delamination of the labels, especially with the automatic machines delaminating the labels and applying them onto objects.
- the labels currently existing on the market generally have a medium release force on their whole surface in order to be rather easily printed and delaminated.
- the release force at the front edges of the labels is increased by irradiation, before printing, thus preventing the labels to be delaminated in the printing machine. After printing the labels, the roll is wound up.
- the roll is then unwound in the reverse direction and the high release edge, that was the front edge, is now the back edge.
- the present front edge has a low release and the labels can easily be delaminated and applied onto objects.
- the release force increases or decreases gradually over a segment of the laminate. For example in mechanically applying labels a gradual change of the release force will enable to have a weak release at the front that grows to a stronger one thus enabling an easy release at the front and a more stronger towards the end.
- a gradient on the final release force that gradient can be applied on the radiation dose thus obtaining a changing radiation dose and thus a changing release force.
- the gradient value can be introduced by means of the input unit 12.
- Pressure-sensitive adhesive laminates are often used for advertising purposes and an image of the product is applied on the front layer which is then made of a material that can be printed on and serves as an image carrier.
- the laminates are often originally rectangular shaped or have a larger dimension than the image, and as the image is not necessarily rectangularly shaped, the image-field, that is the field on which the image of the product is applied, has to be separated from the rest or non-image field.
- a cutting tool is used, for example made of a knife or a laser that is driven along a border line, delimiting the image field from the non-image field.
- the cutting tool is controlled by a computer in order to enable an accurate cutting operation either through the whole laminate or at least through the front sheet .
- the cutting tool enables to separate the image field from the non-image field.
- the image field As generally only the image field needs to be delaminated, the latter is irradiated in order to modify the initial release force and enable an easier delamination.
- the irradiation can be applied only on the image field or only on the non-image field after printing the image, a more accurate process is possible.
- the irradiation is done either before or after cutting, but preferably after cutting as a more reliable radiation is possible on the already cut-out image field.
- the PSA laminate is the one described in the figure 1
- the release force FTM3 is about 0.3 N/25 mm before irradiation. Signs are cut in the whole thickness of the front sheet of the laminate, the adhesive layer being generally partially or totally cut.
- An irradiation device similar to the one of figure 2 irradiates selectively parts of the surface or the whole surface of the non-image fields of the laminate. After irradiation, the release force in the non-image fields that were irradiated is significantly increased, for instance to 2N/ 25mm.
- the adhesive surface of a transfer film is applied with some pressure onto the whole surface of the front sheet of the PSA laminate; the adhesion between the adhesive of the transfer film and the front sheet of the PSA laminate is 1 N/25 mm (FTM1).
- the transfer film is separated from the laminate.
- the irradiated non-image fields of the PSA laminate have a release force (FTM3 :2 N/25 mm) that is higher than the adhesion between the front sheet of the PSA laminate and the adhesive present on the transfer film (FTM3: 1 N/ 25mm).
- the image fields have a low release force (FTM3: 0.3N/ 25 mm).
- the cut pieces of the front sheet of the PSA laminate are transferred onto the transfer film, while the non-image fields are remaining on the carrier.
- the transfer film carrying the image fields cut in the front sheet is then applied with some pressure onto the object that has to be decorated, the transfer film is removed from the object, leaving the object decorated with the image fields of the PSA laminate.
- the advantage provided by the method of the invention is that the non-image fields ( weed zones) are automatically separated from the image fields. In the prior-art methods, the non-image fields are manually separated, necessitating a long manual work for the technician.
- Another advantage of the present invention is the possibility to use the positive (image fields) and negative (non-image fields) cut in the front sheet of the same PSA laminate.
- the non-image fields remain on the release layer because of their high release force (FTM3 : 2 N/25 mm).
- a transfer film with a high adhesion ( FTM1: 4 N/25 mm) on the front sheet is applied onto the whole surface of the front sheet of the PSA laminate, then the separation of the carrier from the transfer film leaves the whole negative image onto the transfer film.
- FTM1 high adhesion
- the PSA laminates are often either stacked or wound into a roll. This however causes the adhesive layer to be compressed due to the pressure of the stacked sheets or the wound roll. Therefore this compression causes a bleeding of the adhesive substance embedded into the adhesive layer(s). Due to the applied pressure, the adhesive substance thus tends to flow to the edges of the laminate. Although the adhesiveness of the adhesive substance on the front layer is generally high, the adhesive substance in contact with the release layer, where the adhesion force is lower, tends to flow towards the edges causing an accumulation of adhesive substance on the edges where a rim is then formed. This accumulation of adhesive substance at the edges causes the different laminates to stick together and to disturb unwinding or de-stacking.
- the present invention offers a solution to this bleeding problem by irradiating the edges of the laminates.
- the irradiation causes the initial release force to be modified so that a stronger release force is obtained at the edge, thus preventing a bleeding at that edge.
- the adhesive substance will more strongly adhere to the release layer at the edges so that the tendency to flow under influence of the applied pressure will be reduced.
- the radiation dose applied on the edge can be determined.
- the irradiation is done on a width that is smaller than 1 millimetre so as not to modify the average release force of the laminate.
- the present invention offers a solution is the shrinkage of the front sheet.
- the front sheet is printed in order to apply a multicolour image thereon, that printing process is carried out in several steps, comprising the printing of the different colours, the heating and cooling of the laminate.
- the front sheet is often made of a polymer material, the latter tends to shrink after heating. That shrinking then leads to positioning problems between the printing of the different colours.
- the present invention proposes to irradiate at least two edges of the laminate by means of an actinic or ionising radiation.
- the two edges are preferably opposite to each other and preferably extend lengthways. By irradiating those edges, the release force increases at those edges, causing an improved adhesion at them and thus decreasing the shrinkage as the front layer adheres more strongly to the carrier along those edges.
- Figure 7 shows schematically a device for delaminating labels of a PSA laminate, in order to apply these labels onto objects in a subsequent step.
- the device selects at station 21 those labels with a weak release force and those labels can be applied onto objects ( not shown).
- the carrier bearing the remaining labels is then wound, which enables to save those unused labels.
- the angles are only indicative for a better understanding of the device.
- the irradiation device 9 is placed upstream of station 21, in order to irradiate selected labels.
- the irradiation device is controlled by the computer (such as shown in figure 2).
- This computer comprises a first selection unit provided for selecting among the supplied labels a first series of labels which have to be delaminated by one of the stations 21 , 22 or 23.
- the computer also comprises a second selection unit provided for selecting among the supplied labels of the first series those which have to be irradiated.
- the computer will send a control signal to the source 9 each time one of such labels of the second series has reached the beam of the source.
- the source Under control of the latter signal the source will emit a radiation burst towards the label in order to modify, the required level, the release force at that location of the label.
- the label At the irradiated location the label will thus have the required release force in order to enable delamination at station 22.
- the labels of the second series can comprise all those of the first series, or some of them.
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Laminated Bodies (AREA)
- Adhesive Tapes (AREA)
- Adhesives Or Adhesive Processes (AREA)
Abstract
Description
Claims
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP99972666A EP1153097A1 (en) | 1998-11-23 | 1999-11-23 | A pressure-sensitive adhesive laminate, a method and a device for modifying an initial release force in such a laminate |
CA002351367A CA2351367A1 (en) | 1998-11-23 | 1999-11-23 | A pressure-sensitive adhesive laminate, a method and a device for modifying an initial release force in such a laminate |
JP2000584016A JP2002530510A (en) | 1998-11-23 | 1999-11-23 | Pressure sensitive adhesive laminates, methods and apparatus for altering the initial peel force of such laminates |
BR9915564-8A BR9915564A (en) | 1998-11-23 | 1999-11-23 | Pressure sensitive adhesive laminate, method and device for modifying an initial release force on such laminate |
AU13682/00A AU1368200A (en) | 1998-11-23 | 1999-11-23 | A pressure-sensitive adhesive laminate, a method and a device for modifying an initial release force in such laminate |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP98122119.5 | 1998-11-23 | ||
EP98122119 | 1998-11-23 | ||
EP99108587.9 | 1999-05-06 | ||
EP99108587 | 1999-05-06 |
Publications (2)
Publication Number | Publication Date |
---|---|
WO2000031199A1 WO2000031199A1 (en) | 2000-06-02 |
WO2000031199A9 true WO2000031199A9 (en) | 2001-04-05 |
Family
ID=26149813
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/BE1999/000151 WO2000031199A1 (en) | 1998-11-23 | 1999-11-23 | A pressure-sensitive adhesive laminate, a method and a device for modifying an initial release force in such a laminate |
Country Status (7)
Country | Link |
---|---|
EP (1) | EP1153097A1 (en) |
JP (1) | JP2002530510A (en) |
CN (1) | CN1331736A (en) |
AU (1) | AU1368200A (en) |
BR (1) | BR9915564A (en) |
CA (1) | CA2351367A1 (en) |
WO (1) | WO2000031199A1 (en) |
Families Citing this family (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6852409B2 (en) * | 2002-02-08 | 2005-02-08 | Bic Corporation | Radiation-cured correction tape |
TW200401237A (en) | 2002-07-05 | 2004-01-16 | Lintec Corp | Laminate sheet, laminate sheet roll, and producing methods therefor |
DE10349963A1 (en) * | 2003-10-24 | 2005-06-02 | Leonhard Kurz Gmbh & Co. Kg | Process for producing a film |
JP4677758B2 (en) * | 2004-10-14 | 2011-04-27 | 日立化成工業株式会社 | Die-bonded dicing sheet, method for manufacturing the same, and method for manufacturing a semiconductor device |
JP4883748B2 (en) * | 2005-01-27 | 2012-02-22 | 日東電工株式会社 | Peeling force adjusting method, pressure-sensitive adhesive layer for optical member and method for producing the same, optical member with pressure-sensitive adhesive, and image display device |
EP1724739B1 (en) * | 2005-03-22 | 2008-10-01 | Schreiner Group GmbH & Co. KG | Labels protected against adhesive bleeding |
CN103119663B (en) * | 2010-09-28 | 2015-06-24 | 三菱制纸株式会社 | Conductive material precursor and conductive material |
CN103496608B (en) * | 2013-09-29 | 2016-01-13 | 大连橡胶塑料机械股份有限公司 | Film continuous lamination device |
AU2014376158B2 (en) * | 2014-01-08 | 2018-05-31 | Avery Dennison Corporation | Articles, compositions, systems, and methods using selectively detackified adhesives |
CN104312453A (en) * | 2014-10-16 | 2015-01-28 | 山东科技大学 | Preparation method of ultraviolet cured silicon-containing acrylate conductive printed adhesive |
FR3030856B1 (en) * | 2014-12-19 | 2018-02-02 | Arjobex | ADHESIVE LABEL |
CN109328218A (en) | 2016-02-22 | 2019-02-12 | 艾利丹尼森公司 | The saturating clear extension content tab of tacky adhesive is removed with selectivity |
CN108546525A (en) * | 2018-06-28 | 2018-09-18 | 四川羽玺新材料股份有限公司 | A kind of release film |
CN115415288B (en) * | 2022-09-02 | 2024-01-23 | 重庆远达烟气治理特许经营有限公司科技分公司 | Laminate processing apparatus |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4201808A (en) * | 1978-06-12 | 1980-05-06 | Union Carbide Corporation | Radiation curable silicone release compositions |
JPS5815537A (en) * | 1981-07-22 | 1983-01-28 | Fujimori Kogyo Kk | Production of release paper |
US4822687A (en) * | 1988-01-22 | 1989-04-18 | Minnesota Mining And Manufacturing Company | Silicone release compositions |
US4985274A (en) * | 1989-08-09 | 1991-01-15 | Dow Corning Corporation | Method for controlling release forces in release coatings |
DE4406976C1 (en) * | 1994-03-03 | 1995-06-22 | Lohmann Therapie Syst Lts | Transfer of adhesive material sections |
-
1999
- 1999-11-23 WO PCT/BE1999/000151 patent/WO2000031199A1/en not_active Application Discontinuation
- 1999-11-23 CA CA002351367A patent/CA2351367A1/en not_active Abandoned
- 1999-11-23 EP EP99972666A patent/EP1153097A1/en not_active Withdrawn
- 1999-11-23 JP JP2000584016A patent/JP2002530510A/en active Pending
- 1999-11-23 BR BR9915564-8A patent/BR9915564A/en not_active IP Right Cessation
- 1999-11-23 AU AU13682/00A patent/AU1368200A/en not_active Abandoned
- 1999-11-23 CN CN99814952A patent/CN1331736A/en active Pending
Also Published As
Publication number | Publication date |
---|---|
EP1153097A1 (en) | 2001-11-14 |
WO2000031199A1 (en) | 2000-06-02 |
BR9915564A (en) | 2001-10-02 |
CA2351367A1 (en) | 2000-06-02 |
AU1368200A (en) | 2000-06-13 |
JP2002530510A (en) | 2002-09-17 |
CN1331736A (en) | 2002-01-16 |
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