TW202103943A - Film and method for manufacturing recovered film using same - Google Patents

Abstract

Provided is a film for satisfactorily removing a release layer by using a film having a thickness of 500 [mu]m or less and having an absorbance peak with a peak absorptivity of at least 10% at the peak top of absorption at wavelengths from 800 nm to 1200 nm or having a mean absorptivity of at least 15% at wavelengths from 800 nm to 1200 nm.

Description

Film and manufacturing method of recycled film using it

The present invention relates to a film that is excellent in removing the release layer provided on the film, and a method for manufacturing a recycled film using the film.

Films are used in various industrial fields. In recent years, with the development of the Internet of Things (IOT, Internet of Things), electronic devices such as CPUs (Central Processing Units) mounted on computers or smartphones have increased dramatically, and they are used to drive electronic devices. The number of multilayer ceramic capacitors (MLCC, Multi-layer Ceramic Capacitors) required has also increased explosively. The usual manufacturing method of MLCC, firstly, on the mold release film formed by disposing the mold release layer on the base film, laminate the ceramic green sheet and the electrode, and then dry and solidify, to form a laminated body including the ceramic green sheet and the electrode ( After the release object), the laminate is peeled from the release film. Next, the laminate including the ceramic green sheet and the electrode peeled from the release film is laminated and fired. In this step, the release film is discarded as useless after peeling the layer containing the ceramic green sheet and the electrode.

That is, due to the explosive increase in the number of MLCCs in recent years, the release film discarded as useless materials has increased, and the load on the environment has gradually become a problem. From the viewpoint of mold releasability, the composition of the mold release layer contained in the mold release film used in the manufacturing step of MLCC is usually a different composition from the composition of the film, so the mold release layer When the release film is directly remelted, the components of the release layer are present in the molten material in the form of foreign matter, and therefore cannot be reused. Patent Document 1 discloses a technique of kneading wax in a film and using it as a film for mold release. In addition, Patent Document 2 discloses a method of washing the release film with a metal brush and reusing it. [Prior Technical Literature] [Patent Literature]

Patent Document 1: International Publication No. 2013/15260 Patent Document 2: Japanese Patent Laid-Open No. 2012-171276

(The problem to be solved by the invention)

However, when wax is used as a release agent, the coating properties of the ceramic slurry used to form the ceramic green sheet to be released, or the release properties of the green sheet obtained by drying the slurry are not full. In addition, since wax is a substance different from the composition of the film, it becomes a problem of foreign matter when it is remelted. In addition, when the mold release film is cleaned with a metal brush, there is a problem that it cannot be cleaned uniformly, or the removability of the release layer is insufficient. (Technical means to solve the problem)

In order to solve the above-mentioned problems, the present invention adopts the following configuration. which is, [I] A thin film with a thickness of 500 μm or less and an absorption peak with an absorbance of 10% or more at the top of a peak with a wavelength of 800 nm or more and 1200 nm or less, or an average absorbance of a wavelength of 800 nm or more and 1200 nm or less 15% or more. [II] The film as in [I], wherein the contact angle between at least one side surface and water is 90° or more. [III] The film of [I] or [II], which has a layer (base material layer) mainly composed of a thermoplastic resin having a melting point of 250° C. or higher, and a layer containing an infrared absorber. [IV] The film of [III], wherein the above-mentioned infrared absorber has sublimation properties. [V] The film as in [IV], wherein the sublimation temperature of the infrared absorber is 280°C or more and 400°C or less. [VI] The film of any one of [III] to [V], wherein the above-mentioned infrared absorber has a phthalocyanine skeleton. [VII] The film according to any one of [III] to [VI], wherein the above-mentioned substrate layer is a layer mainly composed of polyester. [VIII] The film of any one of [I] to [VII], which is used for demolding purposes. [IX] The film of any one of [I] to [VIII], which is used for the following purposes: a release layer is provided on the above-mentioned film, and then the release layer of the film having the release layer is provided to be released After that, the part to be released is demolded from the film with the release layer containing the part to be released, and then the part to be released is removed from the film with the release layer of the part to be released. Residue and release layer. [X] The film as in [IX], wherein the above-mentioned film with the release layer of the released object removes the residue of the release object and the release layer by irradiating at a wavelength of 800 nm or more and 1200 It is implemented with a laser with an oscillation wavelength below nm. [XI] A method of using a film, which is the method of using a film in any of [I] to [X], including: The step of disposing a release layer on the film; The step of arranging the release object on the release layer of the film with the release layer; The step of demolding the object to be released from the film having the release layer containing the release object; and The step of removing the residue of the mold-releasing object and the mold-releasing layer from the film having the mold-releasing layer of the mold-releasing object. [XII] A manufacturing method of recycled film, which is a manufacturing method of recycled film using any one of films [I] to [X], including: Step of setting a release layer on the film of any one of [I] to [X]; The step of arranging the release object on the release layer of the film with the release layer; The step of demolding the mold-released object from the film having the mold-releasing layer containing the mold-released object; and The step of removing the residue of the demolded object and the demolding layer from the film having the demolded release layer of the demolded object. [XIII] The film according to any one of claims [III] to [VIII], wherein the layer containing the above-mentioned infrared absorber has a release agent. [XIV] A film such as [XIII], which is used for the following purposes: set a release object on the film, and then release the release object from the film with the release object, and then release it from the mold The stripped film removes the residue of the stripped object and the layer containing infrared absorber. [XV] A film such as [XIV], wherein the above-mentioned film has been released from the release object to remove the residue of the release object and the layer containing the infrared absorber by irradiating at a wavelength above 800 nm and below 1200 nm Implemented with a laser with an oscillating wavelength. [XVI] A method of using the film, which is the method of using any one of the films from [XIII] to [XV], including: The step of setting the release object on the film; The step of demolding the demolded object from the film with the demolded object; and The step of removing the residue of the released object and the layer containing the infrared absorber from the released film of the released object. [XVII] A method of manufacturing a recycled film, which is a method of manufacturing a recycled film using any one of the films [XIII] to [XV], including: Steps of setting the release object on the film of any one of [XIII] to [XV]; The step of demolding the demolded object from the film with the demolded object; and The step of removing the residue of the released object and the layer containing the infrared absorber from the released film of the released object. (Compared with the effect of previous technology)

According to the present invention, it is possible to provide a film that has good coating properties such as ceramic slurry and is excellent in removing the release layer from the substrate after use, and a method for producing a recycled film using the film.

Hereinafter, specific examples are given to explain the present invention in detail.

The film of the present invention preferably has a resin as a main component. The resin used in the present invention may be any of a thermoplastic resin and a thermosetting resin, and from the viewpoint of good moldability, a thermoplastic resin is preferred.

烯、聚環戊烯等之聚烯烴；以尼龍6、尼龍11、尼龍12、尼龍66為代表之聚醯胺；以乙烯/丙烯共聚物、乙烯/乙烯基環己烷共聚物、乙烯/乙烯基環已烯共聚物、乙烯/丙烯酸烷基酯共聚物、乙烯/丙烯醯基甲基丙烯酸酯共聚物、乙烯/降

烯共聚物、乙烯/乙酸乙烯酯共聚物、丙烯/丁二烯共聚物、異丁烯/異戊二烯共聚物、氯乙烯/乙酸乙烯酯共聚物等為代表之乙烯系單體之共聚物；以聚丙烯酸酯、聚甲基丙烯酸酯、聚甲基丙烯酸甲酯、聚丙烯醯胺、聚丙烯腈等為代表之丙烯酸樹脂；以聚對苯二甲酸乙二酯、聚對苯二甲酸丙二酯、聚對苯二甲酸丁二酯、聚2,6-萘二甲酸乙二酯等為代表之聚酯；以聚環氧乙烷、聚環氧丙烷、聚丙烯二醇為代表之聚醚；以雙乙醯纖維素、三乙醯纖維素、丙醯基纖維素、丁醯基纖維素、乙醯基丙醯基纖維素、硝化纖維素為代表之纖維素酯；以聚乳酸、聚丁二酸丁酯等為代表之生物降解性聚合物；此外亦可使用：聚氯乙烯、聚偏二氯乙烯、聚乙烯醇、聚乙烯醇縮丁醛、聚縮醛、聚乙醇酸、聚碳酸酯、聚酮、聚醚碸、聚醚醚酮、改質聚苯醚、聚苯硫醚、聚醚醯亞胺、聚醯亞胺、聚矽氧烷、四氟乙烯、三氟乙烯、三氟氯乙烯、四氟乙烯-六氟丙烯共聚合體、聚偏二氟乙烯等。As the thermoplastic resin, you can use: polyethylene, polypropylene, poly(1-butene), poly(4-methylpentene), polyisobutylene, polyisoprene, polybutadiene, polyvinylcyclohexyl Alkane, polystyrene, poly(α-methylstyrene), poly(p-methylstyrene), polystyrene

Polyolefins such as olefins and polycyclopentene; polyamides represented by nylon 6, nylon 11, nylon 12, and nylon 66; ethylene/propylene copolymer, ethylene/vinyl cyclohexane copolymer, ethylene/ethylene Cyclohexene copolymer, ethylene/alkyl acrylate copolymer, ethylene/propylene methacrylate copolymer, ethylene/

Copolymers of vinyl monomers represented by ethylene copolymers, ethylene/vinyl acetate copolymers, propylene/butadiene copolymers, isobutylene/isoprene copolymers, vinyl chloride/vinyl acetate copolymers, etc.; Acrylic resin represented by polyacrylate, polymethacrylate, polymethyl methacrylate, polyacrylamide, polyacrylonitrile, etc.; to polyethylene terephthalate, polytrimethylene terephthalate , Polybutylene terephthalate, polyethylene 2,6-naphthalate, etc. as the representative polyester; polyethylene oxide, polypropylene oxide, polypropylene glycol as the representative polyether; Cellulose esters represented by diacetyl cellulose, triacetyl cellulose, acryl-based cellulose, butyryl cellulose, acetyl-propyl cellulose, nitrocellulose; polylactic acid, polysuccinic acid Butyl ester and other biodegradable polymers are represented; in addition, it can also be used: polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl butyral, polyacetal, polyglycolic acid, polycarbonate, Polyketone, polyether ether, polyether ether ketone, modified polyphenylene ether, polyphenylene sulfide, polyetherimide, polyimide, polysiloxane, tetrafluoroethylene, trifluoroethylene, trifluorochloride Ethylene, tetrafluoroethylene-hexafluoropropylene copolymer, polyvinylidene fluoride, etc.

Among them, polyolefin, acrylic, polyester, cellulose ester, polyvinyl butyral, polycarbonate, and polyether are more preferred. From the standpoint of strength, formability, and heat resistance, polyester is more preferred. .

The polyester referred to in the present invention has a dicarboxylic acid component and a diol component. In addition, in this specification, the term "constituents" means the smallest unit that can be obtained by hydrolyzing polyester. Examples of the dicarboxylic acid constituents constituting the polyester include terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, and 2,6-naphthalenedicarboxylic acid. Aromatic dicarboxylic acids such as formic acid, 1,8-naphthalenedicarboxylic acid, 4,4'-diphthalic acid, and 4,4'-diphenyl ether dicarboxylic acid, or ester derivatives thereof.

In addition, as the diol component constituting the polyester, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,2-butanediol, 1, Aliphatic diols such as 3-butanediol, alicyclic diols such as cyclohexanedimethanol and spirodiol, those formed by connecting a plurality of the above-mentioned diols, etc. Among them, from the viewpoint of mechanical properties and transparency, as polyester, polyethylene terephthalate (PET), polyethylene 2,6-naphthalate (PEN), and polyesters can be suitably used. Part of the dicarboxylic acid component of PET is a polyester obtained by copolymerizing isophthalic acid or naphthalene dicarboxylic acid, and a part of the glycol component of PET is copolymerized with cyclohexane dimethanol, spirodiol, and diethylene glycol. Chengzhi polyester.

The film of the present invention must have an absorption peak with an absorbance of 10% or more at the top of a peak with a wavelength of 800 nm or more and 1200 nm or less, or an average absorbance of 15% or more with a wavelength of 800 nm or more and 1200 nm or less. Furthermore, the film of the present invention as long as it has at least an absorption peak with an absorbance of 10% or more at the top of a peak with a wavelength of 800 nm or more and 1200 nm or less, or an average absorbance of 15% or more with a wavelength of 800 nm or more and 1200 nm or less. can. Therefore, a film having a peak top with a wavelength of 800 nm or more and 1200 nm or less with an absorbance of 10% or more, and a film having an average absorbance of 15% or more with a wavelength of 800 nm or more and 1200 nm or less is certainly included in the present invention . The absorbance at the top of the absorbance peak is more preferably 15% or more, and still more preferably 20% or more. In addition, the average absorbance at a wavelength of 800 nm or more and 1200 nm or less is preferably 20% or more. Since this wavelength has an absorption peak, the release layer can be easily removed by irradiating laser light having an oscillation wavelength with a wavelength of 800 nm or more and 1200 nm or less.

The thickness of the film of the present invention must be 500 μm or less. When it exceeds 500 μm, there is a phenomenon that the operability when removing the release layer is poor. It is preferably 250 μm or less, more preferably 100 μm or less, still more preferably 37 μm or less, and most preferably 24 μm or less. If the thickness of the film becomes thinner, the strength may be insufficient, and the removal of the release layer or the transport of the film may not be possible. Therefore, it is preferably 10 μm or more.

The film of the present invention preferably has a contact angle of at least one side surface with water of 90° or more. When the contact angle with water of at least one side surface is 90° or more, when the film of the present invention is used as a film for mold release, the mold release property becomes good. For example, when a ceramic green sheet is made on the surface of the film of the present invention, the mold release of the green sheet is good. The upper limit of the water contact angle is not particularly limited, but it is preferably 110° or less. When it exceeds 110°, there is the following phenomenon: when the ceramic slurry is coated on the film, the slurry is repelled and the green sheet cannot be obtained.

The film of the present invention preferably has a layer (base material layer) mainly composed of a thermoplastic resin having a melting point of 250°C or higher, and a layer containing an infrared absorber. The infrared herein refers to a wavelength of 800 nm or more and 1200 nm The light below. In addition, the "main component of resin having a melting point of 250°C or higher" means that the content of the resin having a melting point of 250°C or higher in the base layer is 50% by weight or higher, more preferably 90% by weight or higher. If it has a layer containing a thermoplastic resin with a melting point of 250°C or higher as the main component, the heat resistance is improved, and therefore, the operability when used as an engineering film or the like is good. In addition, when the layer containing the infrared absorber is destroyed and removed by the following method, the damage to the substrate layer can be reduced. The melting point of the thermoplastic resin constituting the base layer of the film of the present invention is more preferably 250°C or higher and 340°C or lower, and still more preferably 252°C or higher and 300°C or lower. The film of the present invention has a layer mainly composed of a thermoplastic resin with a melting point of 250°C or higher, and a layer containing an infrared absorber. Therefore, the layer mainly composed of a resin with a melting point of 250°C or higher can improve handleability. , It is easy to set the absorbance at the wavelength of 800 nm to 1200 nm in the preferred range by the layer containing the infrared absorber. As a method of providing a layer containing an infrared absorber, a method of forming a substrate layer and a layer containing an infrared absorber by co-extrusion, or by gravure coating, Meyer rod coating, air knife coating, etc. A method of applying cloth, knife coating, spin coating, etc., to provide a layer containing an infrared absorber on the substrate layer. From the viewpoint that the infrared absorber can be contained at a higher concentration, the method of providing the layer containing the infrared absorber is preferably a method using coating. In the film of the present invention, the preferred layer thickness ratio between the substrate layer and the infrared absorber-containing layer is the thickness of the substrate layer relative to the thickness of the infrared absorber-containing layer (thickness of the substrate layer/infrared absorber The thickness of the layer) is 10 or more. More preferably, it is 15 or more. The upper limit of the thickness ratio is preferably 1000 or less.

In the present invention, if the base material layer contains polyester as a main component, the handleability can be particularly good, and the release layer can be easily removed by the following method, which is preferable.

Furthermore, in the present invention, the base material layer preferably has an average absorbance of 10% or less with a wavelength of 800 nm or more and 1200 nm or less. By setting the absorbance of the substrate layer in this range, when the film of the present invention is irradiated with a laser having an oscillation wavelength of 800 nm or more and 1200 nm or less, energy can be concentrated on the layer containing the infrared absorber. Therefore, not only the removability becomes good, but also the deterioration of the resin constituting the base layer can be suppressed. More preferably, it is 8% or less.

Examples of the infrared absorber in the film of the present invention include pigments containing metals such as Al, Cu, Au, Ag, and Ti, or inorganic substances such as carbon black, or organic substances as main components. If the layer containing the infrared absorber is irradiated with a laser with a wavelength of 800 nm or more and 1200 nm or less with an oscillation wavelength, the infrared absorber absorbs infrared rays and has heat energy. Therefore, if there is a layer containing an infrared absorber or a layer adjacent to it At this time, these layers are easily destroyed and removed.

In addition, the infrared absorber in the film of the present invention preferably has sublimation properties. In the case of sublimation, the volume of the infrared absorber increases sharply when energy greater than the heat of sublimation is applied to the infrared absorber. Therefore, when there is a layer containing an infrared absorber and a layer adjacent to it, these layers are easily broken and removed, which is preferable. The sublimation temperature of the infrared absorber is preferably 280°C or higher and 400°C or lower. When the temperature is less than 280°C, in the step of using the film of the present invention as a release film (a step of placing a release object on the film, etc.), there is a phenomenon of sublimation of the infrared absorber, which prevents When used as a release film. When the temperature exceeds 400°C, the energy required for the sublimation of the infrared absorber may increase, so the removal performance of the release layer may be poor. Moreover, it is preferable that the said infrared absorber has a phthalocyanine skeleton. Since it has a phthalocyanine skeleton, it has high solubility in organic solvents such as toluene or ethanol, and the solvent can be used to coat the substrate layer at a high concentration, which is preferable.

In the film of the present invention, the layer containing the infrared absorber may also contain a substance that is easily vaporized due to the heat generated by the infrared absorber absorbing light with a wavelength of 800 nm to 1200 nm. As the easily vaporized substance, for example, nitrocellulose can be suitably used. Especially when the infrared absorber has sublimation properties, the substance easily vaporized by the energy of sublimation also vaporizes, so that the layer adjacent to the layer containing the infrared absorber can be effectively removed.

In the film of the present invention, it is also one of the preferred embodiments that the layer containing an infrared absorber contains a release agent. By making the layer containing the infrared absorber contain a release agent, it is not necessary to separately provide a release layer with good release properties, and therefore it is possible to produce a film with excellent step stability. As the mold release agent used in the present invention, for example, alkyd resin mold release agent, polyolefin mold release agent, long-chain alkyl containing resin mold release agent, fluorine-based mold release agent, silicone-based mold release agent, Release agent, mixed of organic and polysiloxane or copolymerized resin release agent, etc. Among them, in terms of the coating properties of the ceramic slurry used to make ceramic green sheets, and the mold release properties of the ceramic green sheets obtained by drying and curing it, it is particularly suitable to use a silicone release agent .

On the other hand, it can also be cited as a preferable aspect that the film of the present invention is additionally provided with a layer containing a release agent. By setting it as this structure, it is easy to make the releasability of a to-be-released object good.

Next, as the detailed form and usage method of the film of the present invention, the film having a layer mainly composed of polyester and a layer containing an infrared absorber is described, but the present invention is not limited to these .

In the film of the present invention, the layer containing polyester as the main component can suitably use a method of melting polyester to form a film. That is, the layer mainly composed of polyester can use a polyester film obtained by passing through the following steps: the step of cooling and solidifying the polyester from a molten state to obtain a sheet, and the glass transition of the polyester in the stretching step A step of sequential biaxial stretching or simultaneous biaxial stretching at a temperature above the temperature, and a step of heat treatment at a temperature below the melting point of the polyester. Next, the method of providing the layer containing the infrared absorber will be described. As a method of providing a layer containing an infrared absorber, the infrared absorber can be dissolved in a solvent such as toluene or methyl ethyl ketone (MEK), and then a solution that has been sufficiently stirred with a homogenizer is applied by coating. The method of setting on the substrate layer is the preferred method. When the infrared absorber-containing layer contains the above-mentioned release agent, it is preferable to use the same solvent as the infrared absorber, and dissolve the release agent such as silicone resin in the same solvent as the infrared absorber. . In particular, as a mold release agent, a polysiloxane mold release agent having a structure of a polysiloxane that is cured by an addition reaction by heating has high solubility in toluene, MEK, etc., and is easily contained in an infrared absorber. Therefore, it is better.

The solution containing the infrared absorber and silicone resin obtained as described above is coated on a polyester film by coating, and the solvent is evaporated by drying in an oven or the like, thereby obtaining the film of the present invention . As the coating method, general coating methods such as gravure coating, Meyer bar coating, air knife coating, and knife coating can be used.

In the film of the present invention, it is also a preferred embodiment to separate the infrared absorber-containing layer and the release layer. In this case, if a layer containing an infrared absorber is provided on the substrate layer, and a release layer is further provided thereon, the contact angle between the film of the present invention and water can be set in a preferable range. Better. When the infrared absorber-containing layer and the release layer are separately provided, the method of providing the infrared absorber-containing layer can be listed as follows: production is preliminarily provided with an infrared absorber by in-line coating A method of setting a layer containing a release agent as the release layer; or using a die nozzle or the like to simultaneously carry out two-layer tandem coating to provide a layer containing an infrared absorber and a release layer containing The method of the layer of release agent.

唑啉樹脂、三聚氰胺樹脂、環氧樹脂、碳二醯亞胺樹脂、異氰酸酯樹脂作為交聯劑亦為較佳之實施形態。When a layer containing an infrared absorber is provided by tandem coating, it is preferable to disperse the infrared absorber in polyester resin, polycarbonate resin, epoxy resin, alkyd resin, acrylic resin, urea resin, etc. Polyurethane resin. Especially when the infrared absorber has a phthalocyanine skeleton, from the viewpoint of dispersibility, an acrylic resin is preferred. If the infrared absorber is uniformly dispersed in the layer containing the infrared absorber, it is easy to destroy and remove the layer containing the infrared absorber by irradiating the following laser with an oscillation wavelength at a wavelength of 800 nm or more and 1200 nm or less. In addition, from the viewpoints of environmental protection, resource saving, and exhaust of organic solvents during manufacturing, the above-mentioned resin for dispersing the infrared absorber is preferably an emulsion type dispersed in water. Also, from the viewpoint of adhesion to the substrate, that is, the film, add

Oxazoline resins, melamine resins, epoxy resins, carbodiimide resins, and isocyanate resins are also preferred embodiments as crosslinking agents.

When two layers are applied in tandem at the same time using a die nozzle, etc., and a layer containing an infrared absorber and a layer containing a release agent as a release layer are provided, the environment is protected, resources are saved, and organic solvents are used during manufacturing. From the viewpoint of the problem of air exhaust or the coatability of the infrared absorbing layer, it is preferable to use a release agent obtained by dispersing polysiloxane in water as an emulsion.

In the case where the layers are provided by tandem coating, from the viewpoint of drying the coating film, in the case of obtaining a film as a base layer by simultaneous biaxial stretching, it is preferable to coat before stretching On the film, when the film is obtained by successive biaxial stretching, coating is preferably performed after the longitudinal stretching step.

Taking the case of using the film as a step film for multilayer ceramic capacitors (MLCC) as an example, the preferred method of using the film of the present invention obtained as described above will be described below.

When the mold-released object provided on the film of the present invention is used as a film for the step of MLCC, it is formed of a ceramic slurry containing a dielectric paste. The so-called dielectric paste refers to the compound oxide or various compounds of oxides, such as carbonates, nitrates, hydroxides, organometallic compounds, etc. powders, which are used as dielectric materials, are mixed with an organic carrier to form a paste. By. The so-called organic carrier system refers to a binder resin dissolved in an organic solvent. As the binder resin used in the organic vehicle, a polyvinyl butyral resin can be suitably used from the viewpoint of coatability. The organic solvent used in the organic vehicle is not particularly limited. For example, organic solvents such as terpineol, ethanol, butyl carbitol, acetone, and toluene are used. The ceramic slurry containing the dielectric paste is applied on the film of the present invention by die nozzle coating method, doctor blade method, etc., and dried at a temperature of 50°C to 100°C to be formed into a sheet shape. Peel off. The peeling method is not particularly limited, and it is usually cut into a cut of a predetermined size to be peeled off and performed by suction.

The film of the present invention can be suitably used for the following purposes: a release layer is provided on the film of the present invention, and then an object to be released is placed on the film, and the object to be released is demolded, and then removed from the film to be released. Residues and layers containing infrared absorbers. As a method of removing the residue of the mold-released object and the layer containing the infrared absorber from the film of the present invention, it is preferably performed by irradiating a laser having an oscillation wavelength of 800 nm or more and 1200 nm or less. By irradiating the film of the present invention with a laser having the oscillation wavelength, the layer containing the infrared absorber of the film of the present invention efficiently absorbs the photon energy of the laser, and the layer decomposes and foams. Thereby, it is possible to destroy and remove the infrared-absorbing layer and the layer adjacent to it, and to destroy and remove the layer (the release layer or the residue of the released object) further adjacent to it. By destroying and removing the infrared-absorbing layer and the layer adjacent to it, and destroying and removing the layer adjacent to it (the release layer or the residue of the released object), only the film that becomes the substrate (hereinafter, there are It is called recycling film). As a result, the recovered film is re-melted and formed into fragments, used as a regenerated raw material for film production, thereby making it again into a film for purposes such as providing a layer containing a release agent on the film and reuse it, so it can be reused. Reduce waste and reduce consumption of petroleum resources.

When a release agent is contained in the infrared absorber-containing layer of the film of the present invention, it can be suitably used for the following purposes: set the release object on the film, and then release the release object from the film Removal of the residue of the demolded object and the layer containing infrared absorber.

As laser irradiation, for example, the laser light having an oscillation wavelength at a wavelength of 800 nm or more and 1200 nm or less is applied to a layer having an absorption peak at a wavelength of 800 nm or more and 1200 nm, especially a layer containing an infrared absorber. Therefore, it can be irradiated from the substrate side of the film of the present invention, and can also be irradiated from the side where the residue of the release material exists.

The laser may be a pulse wave or a continuous wave. From the viewpoint of irradiating the film continuously and without omission, it is preferably a continuous wave. Furthermore, from the viewpoint of the efficiency of the reactivity of the layer containing the infrared absorber, the oscillation intensity of the laser light is preferably 5 W or more and 50 W or less. The irradiation time is not particularly limited, but the irradiation is preferably 0.1 second or longer.

As described above, the film of the present invention can obtain only the film (recycled film) as the base material after removing the residue of the release object and the release layer from the film of the present invention. As a result, the recovered film is remelted and formed into fragments, which can be used as a regenerated raw material for film production, or it can be reused as a film with a layer containing a release agent provided on the film, thereby reducing waste , To reduce the consumption of oil resources.

[Characteristic evaluation method] A. Absorbance of film (%) The absorbance was measured using a spectrophotometer (U-4100 Spectrophotomater) manufactured by Hitachi, Ltd. Furthermore, the frequency band parameter is set to 2/servo, the gain is set to 3, and the detection speed is 120 nm/min. in the range of 800 nm to 1200 nm.

Subtract the transmittance of the film from 100 and use it as the absorbance of the film. In the range of 800 nm to 1200 nm, when there is a peak with a half-value width of 100 nm or less, find the absorbance at the top of the peak, and when there is no peak, find the absorbance at 800 nm to 1200 nm The average value is taken as the absorbance of the film.

B. The contact angle of water on the side of the release layer of the film (°) After placing the sample in a gas environment with a room temperature of 23°C and a humidity of 65% for 24 hours, use the contact angle meter CA-D (manufactured by Kyowa Interface Science Co., Ltd.) in this gas environment and store it under the same conditions. The distilled water is measured.

C. The thickness of each layer of the film (μm) When the film is a laminated film, the thickness of each layer is obtained by the following method. Use a slicer to cut out the cross section of the film in a direction parallel to the width direction of the film. Observe the cross section under a scanning electron microscope at a magnification of 5000 times, and measure the thickness of each layer of the build-up layer.

D. Coatability of dielectric paste (part to be released) 100 parts by weight of barium titanate (trade name HPBT-1 manufactured by Fuji Titanium Industry Co., Ltd.), 10 parts by weight of polyvinyl butyral (trade name BL-1 manufactured by Sekisui Chemical Co., Ltd.), phthalic acid 5 parts by weight of dibutyl formate and 60 parts by weight of toluene-ethanol (30:30 by weight) were added with glass beads with a number average particle size of 2 mm, mixed and dispersed by a jet mill for 20 hours, and then filtered. Prepared as a paste-like dielectric paste. The obtained dielectric paste is coated on the film of the present invention in such a way that the thickness after drying becomes 2 μm using a die nozzle coater, is dried, and is wound to obtain a green sheet with a release film. The rolled blank sheet is rolled out and visually observed without peeling from the release film to confirm the presence or absence of pinholes or the coating state of the sheet surface and ends. Furthermore, the observed area is 300 mm wide and 500 mm long. The green sheet formed on the release film was irradiated from the back with a 1000 lux backlight unit while observing pinholes due to coating defects, and evaluated as follows. A has good manufacturability. A: The number of pinholes is 5 or less. B: There are 6 or more pinholes. E. Peelability of dielectric paste (part to be demoulded) Put a polyester adhesive tape (No. 31B manufactured by Nitto Denko Corporation, 19 mm in width) on the surface of the blank with release film obtained in D., using VPA manufactured by Kyowa Interface Chemistry (Stock) -H200 and measure the strength of 180° peeling, and evaluate as follows.

A: The peel strength is 30 mN/50 mm or less.

B: The peel strength exceeds 30 mN/50 mm.

F. Removability of the release layer Irradiate laser light on the film after peeling off the part to be released by the method described in item E. While irradiating, it attracts the dust generated on the surface of the film.

(F-1) Determination of Si element content by photoelectron spectroscopy (atom%) Under the following equipment and conditions, obtain the element concentration of Si element (atom%) on the surface of the film on the release layer side after laser light irradiation . The element concentration (atom %) of Si element on the film surface on the release layer side after laser light irradiation represents the residual amount of Si compound used as a release agent. When the amount is small, it means that the release layer is removed . Device: K-Alpha+ (manufactured by Thermo Scientific) Excitation X-ray: Monochrome Al Kα _{1 , 2} rays (1486.6 eV) X-ray diameter: 400 μm Photoelectron escape angle: 90° (the inclination angle of the detector relative to the sample surface ) A: Si element concentration is less than 10 atomic% B: Si element concentration is 10 atomic% or more and less than 15 atomic% C: Si element concentration is 15 atomic% or more and less than 20 atomic% D: Si element concentration is 20 At least atomic%. (In Example 12, the same evaluation was performed using the F element concentration (atom %) of the film surface on the release layer side after laser light irradiation.) (F-2) For the laser light irradiation on the release layer side For the surface of the film, calculate the contact angle of water in the same way as in item B. The lower the contact angle of the water on the release layer side after the laser light is irradiated, the more the release layer is removed.

A: The contact angle is less than 80° B: The contact angle is 80° or more and less than 90° C: The contact angle is more than 90° and less than 100° D: The contact angle is 100° or more. G. Melting point Tm (℃) of the base material of the film Using the method based on JISK 7122 (1999), using the differential scanning calorimetry device "Robot DSC-RDC220" manufactured by Seiko Instruments Inc., and using the DISC Session "SSC/5200" in the data analysis, implement the following procedures Determination. Weigh a 5 mg sample in the sample pan, and heat the sample from 25°C to 300°C (1st RUN) at a temperature increase rate of 10°C/min. Obtain a differential scanning calorimetry chart of 1st RUN (the vertical axis is heat energy, and the horizontal axis is temperature). The peak temperature of the endothermic peak of the differential scanning calorimetry chart of this 1st Run was calculated and set as Tm (°C). [Example]

Hereinafter, the present invention will be described with reference to examples, but the present invention is not necessarily limited to these.

[Production of PET-1] Using terephthalic acid and ethylene glycol, using antimony trioxide as a catalyst, polymerization is carried out by conventional methods to obtain melt polymerized PET. The obtained melt polymerized PET has a glass transition temperature of 81°C, a melting point of 255°C, an intrinsic viscosity of 0.62, and a terminal carboxyl group content of 20 eq./t.

[Production of PET-A] To 99.7 parts by weight of PET-1, add 0.3 parts by weight of infrared absorber FDN-010 (Vanadium phthalocyanine complex, sublimation temperature 340℃) manufactured by Yamada Chemical Industry Co., Ltd., and use the attached row The pore extruder is kneaded while the pressure is kept below 1 kPa to obtain PET-A containing infrared absorber. The glass transition temperature is 81°C, the melting point is 255°C, the intrinsic viscosity is 0.61, and the amount of terminal carboxyl groups is 30 eq./t.

[Production of PET-B] Add 1 part by weight of infrared absorber FDN-010 (phthalocyanine vanadium complex, sublimation temperature 340℃) manufactured by Yamada Chemical Industry Co., Ltd. to 99 parts by weight of PET-1. The pore extruder is kneaded while the pressure is kept below 1 kPa to obtain PET-B containing infrared absorber. The glass transition temperature is 81°C, the melting point is 255°C, the intrinsic viscosity is 0.59, and the amount of terminal carboxyl groups is 38 eq./t.

[Production of PET-C] To 95 parts by weight of PET-1, 5 parts by weight of infrared absorber FDN-010 (phthalocyanine vanadium complex, sublimation temperature 340℃) manufactured by Yamada Chemical Industry Co., Ltd. is added, and the attached row is used. The pore extruder is kneaded while the pressure is kept below 1 kPa to obtain PET-C containing infrared absorber. The glass transition temperature is 78°C, the melting point is 251°C, the intrinsic viscosity is 0.50, and the amount of terminal carboxyl groups is 51 eq./t.

[Production of Paint A] Using toluene as a solvent, 100 parts by weight of addition reaction type silicone resin release agent (manufactured by Dow Corning Toray Silicone (stock), trade name LTC750A, with polysiloxane structure), platinum 2 parts by weight of the catalyst (manufactured by Dow Corning Toray Silicone Co., Ltd., trade name SRX212) was adjusted to a solid content of 5% by weight, and coating agent A was obtained.

[Production of paint B] In 100 parts by weight of an aqueous dispersion of polysiloxane release agent (with polysiloxane structure) containing alkenyl groups/12 parts by weight of aqueous dispersion of polysiloxane containing Si-H groups, An aqueous dispersion of a nonionic acrylic resin (emulsifier: nonionic emulsifier) described later as an alkyl resin is mixed, diluted with water, and adjusted so that the solid content concentration becomes 5% by weight to obtain coating B .

[Preparation of Coating Agent C] The non-silicone release agent FS9200 manufactured by Nippon Chemical Co., Ltd. was used, diluted with toluene, and adjusted so that the solid content concentration became 10% by weight to obtain coating agent C.

[Preparation of paint a] 50 parts by weight of acrylic resin and 50 parts by weight of methylol-type melamine crosslinking agent ("NIKALAC (registered trademark)" MW12LF manufactured by Sanwa Chemical Co., Ltd.), the solid content concentration is 8 Mix and stir in water to obtain paint a by weight%.

[Production of paint D] 60 parts by weight of 878B manufactured by Taiping Chemical Co., Ltd., which contains carbon black and nitrocellulose, and 20 parts by weight of Epikote828 manufactured by Mitsubishi Chemical Co., Ltd., which is used as epoxy resin. Hardener: 19 parts by weight of melamine resin ("U-VAN (registered trademark)" 2061 manufactured by Mitsui Chemicals Co., Ltd.) and 1 part by weight of catalyst (Lightester PM manufactured by Kyoei Chemical Co., Ltd.), based on solid content concentration It was dissolved in a solvent (90 parts of methyl isobutyl ketone, 10 parts by weight of dimethylformamide) so as to become 10% by weight, and paint D was obtained.

[Production of paint E] 60 parts by weight of "Clear Lacquer (registered trademark)" manufactured by Hwashin Paint Co., Ltd. as a paint containing nitrocellulose, and manufactured by Mitsubishi Chemical Co., Ltd. as epoxy resin Epikote828 20 parts by weight, 19 parts by weight of melamine resin ("U-VAN (registered trademark)" 2061 manufactured by Mitsui Chemicals Co., Ltd.) as hardener and 1 part by weight of catalyst (Lightester PM manufactured by Kyoei Chemical Co., Ltd.) Mix together to obtain paint D.

(Example 1) Using paint a, add FDN-010 (vanadium phthalocyanine) manufactured by Yamada Chemical Industry Co., Ltd. as an infrared absorber at a concentration of 1% by weight relative to the total solid content of the paint. The sublimation temperature is 340°C ) Stir to obtain paint a-1. In addition, after drying the PET-1 in vacuum at 160°C for 2 hours, it was put into an extruder, melted at 280°C, and extruded through a die nozzle onto a casting drum with a surface temperature of 25°C. The sheet is not stretched. Then, after preheating the sheet with a heated roll set, it stretched 3.5 times in the longitudinal direction (MD direction) at a temperature of 90°C, and then cooled it with a roll set at a temperature of 25°C to obtain a single sheet. Axis stretch film. After the coating agent a-1 was stretched and dried to a thickness of 0.1 μm by using a Meyer rod, the uniaxially stretched film was applied to the obtained uniaxially stretched film. While holding the two ends of the film with a clamp, the film was placed in the tenter. The heating zone at a temperature of 110°C extends 4.0 times along the width direction (TD direction) at right angles to the longitudinal direction. Furthermore, the heat treatment area in the tenter frame was heat-fixed for 10 seconds at a temperature of 230°C. Then, after uniformly slow cooling in the cooling zone, it was wound up to obtain a film having a substrate layer with a thickness of 30 μm and a layer with an infrared absorber with a thickness of 0.1 μm. On the surface of the layer with infrared absorber of the obtained film, coating agent A is further applied, and the coating thickness after drying is applied with a gravure coater so that the coating thickness after drying becomes 0.1 μm, and the film is dried and cured at 100°C for 20 seconds , Thereby obtaining a film laminated with a release layer. The properties of the film are shown in the table. It is a film with no problems with the coating and peeling properties of the dielectric paste.

In addition, the removability of the release layer of the film was evaluated in accordance with item F. That is, the blank produced according to item D. is peeled into a size of 10 cm×10 cm according to the method of item E., and the part is irradiated with continuous wave laser light with a wavelength of 1064 nm and an intensity of 20 W, which attracts the film After the dust generated on the surface, the residual of the release layer was evaluated by measuring the Si element content or the contact angle of water. The laser device uses the laser marker MDX1500 manufactured by Keynes. Since the amount of Si element as a component of the release agent is relatively small, and the contact angle with water is less than 90°C, it is a film with excellent removability of the release layer.

(Examples 2～4, 16) Except changing the infrared absorber concentration and coating thickness of the infrared absorbing layer, and the film thickness of the substrate as shown in the table, the same procedure as in Example 1 was carried out to obtain a film. The characteristics are shown in the table.

In Example 2, the concentration of the infrared absorber was higher, and in Example 3, the coating thickness of the layer containing the infrared absorber was thicker, so it was a film with excellent release layer removability. In Example 4, the intensity of the laser light was set to 10 W, and sufficient removability was still obtained.

In Example 16, the thickness of the base film is made thinner, so the peeling force of the dielectric paste is reduced, and it is a film with excellent operability.

(Example 5) Use the carbon black (non-sublimable) water dispersion (WD-CB2) manufactured by Daito Chemical Industry Co., Ltd. instead of the infrared absorber of Example 1, and add it to the concentration described in the table, except Other than that, it carried out similarly to Example 1, and obtained the film. The characteristics are shown in the table. Although the film of Example 5 does not show a clear peak (maximum value) in the frequency band of wavelengths above 800 nm and below 1200 nm, the average absorbance at wavelengths above 800 nm and below 1200 nm is relatively high. It is a part of the release layer. Film with excellent removability.

(Example 6) Use the infrared absorber FDN-003 (copper phthalocyanine complex, sublimation temperature 380°C) manufactured by Yamada Chemical Industry Co., Ltd. instead of the infrared absorber of Example 1, and add it to the concentration stated in the table Except for this, the same procedure as in Example 1 was carried out to obtain a film. The characteristics are shown in the table. In addition, in order to remove the mold release layer, the laser device uses a pulse laser diode (L11348-307-05) manufactured by Hamamatsu Photonics, which is performed by continuous wave. The removability of the release layer is shown in the table. It is a film with no problem with the removability of the release layer.

(Example 7) Add the infrared absorber FDN-003 (copper phthalocyanine complex, sublimation temperature is 380℃) manufactured by Yamada Chemical Industry Co., Ltd. and FDN manufactured by Yamada Chemical Industry Co., Ltd. at a concentration of 1% by weight. Except for -010 (vanadium phthalocyanine, sublimation temperature: 340°C) instead of the infrared absorber of Example 1, the same procedure as in Example 1 was carried out to obtain a thin film. The characteristics are shown in the table. In addition, in order to remove the mold release layer, the laser device uses MDX1500 and L11348-307-05 to perform continuous wave. The removability of the release layer is shown in the table. It is a film with no problem with the removability of the release layer.

(Example 8) After the PET-1 was vacuum-dried at 160°C for 2 hours, it was put into an extruder, melted at 280°C, and extruded through a die nozzle onto a casting drum with a surface temperature of 25°C to produce unstretched Sheet. Then, the sheet is preheated by a heated roller set, and then stretched 3.5 times in the longitudinal direction (MD direction) at a temperature of 90°C, and then cooled by a roller set at a temperature of 25°C to obtain a uniaxial Stretch film. On the obtained uniaxially stretched film, the coating agent a-1 is adjacent to the film, and then the coating agent B is adjacent to the layer formed by the coating agent a-1, and the coating agent is applied by the die nozzle coating method. a-1 and coating agent B are adjusted so that the thickness after stretching and drying becomes 0.1 μm respectively, and the coating is carried out at the same time. While holding the two ends of the film with a clamp, it is heated at a temperature of 110 ℃ in the tenter. The area extends 4.0 times in the width direction (TD direction) at right angles to the longitudinal direction. Furthermore, the heat treatment area in the tenter frame was heat-fixed for 10 seconds at a temperature of 230°C. Then, after uniformly slow cooling in the cooling zone, winding was performed to obtain a film having a substrate layer with a thickness of 30 μm, a layer with an infrared absorber with a thickness of 0.1 μm, and a release layer with a thickness of 0.1 μm. The removal of the release layer was performed in the same manner as in Example 1. The characteristics and the removability of the release layer are shown in the table. It is a film with no problem with the removability of the release layer.

(Example 9) Add FDN-010 (vanadium phthalocyanine, sublimation temperature 340°C) manufactured by Yamada Chemical Industry Co., Ltd. as an infrared absorber so that the concentration of solid content of paint A becomes 3% by weight, and stir. Obtain paint A-1. In addition, after drying the PET-1 in vacuum at 160°C for 2 hours, it was put into an extruder, melted at 280°C, and extruded through a die nozzle onto a casting drum with a surface temperature of 25°C to produce a fabric. Extend the sheet. Then, the sheet is preheated by a heated roller set, and then stretched 3.5 times in the longitudinal direction (MD direction) at a temperature of 90°C, and then cooled by a roller set at a temperature of 25°C to obtain a uniaxial Stretch film. One side uses a clamp to hold the two ends of the obtained uniaxially stretched film, and the other side stretches 4.0 times in the width direction (TD direction) at right angles to the longitudinal direction of the heating zone at a temperature of 110°C in the tenter. Furthermore, the heat treatment area in the tenter frame was heat-fixed for 10 seconds at a temperature of 230°C. Then, after uniformly slow cooling in the cooling zone, it was wound up to obtain a film with a thickness of 30 μm. Use coating agent A-1 on one side of the obtained film to coat with a gravure coater so that the coating thickness after drying becomes 0.1 μm, and dry and harden at 100°C for 20 seconds, whereby the laminate has infrared absorption Layer of agent and release agent to obtain a film. The characteristics are shown in the table.

In addition, the removability of the release layer was implemented in the same manner as in Example 1. It can be seen that since the infrared absorber and the release agent are contained in the same layer, they are easy to react, and it is a film with excellent release properties.

(Example 10) In Example 10, the content of the infrared absorber was changed as shown in the table, except that the film was obtained in the same manner as in Example 9, and the removability of the release layer was confirmed. The characteristics are shown in the table. It is a film with a large amount of infrared absorber added and excellent removability of the release layer.

(Example 11) The film of Example 10 was used, and the laser light intensity for removing the mold release layer was changed as shown in the table, and the evaluation was performed in the same manner as in Example 10, except that the intensity of the laser light was changed. The results are shown in the table. It can be seen that the addition amount of the infrared absorber is large, and even if the intensity of the laser light is reduced, the removability of the release layer is excellent.

(Example 12) The following paint was prepared as paint C-1: the paint was added with FDN-010 manufactured by Yamada Chemical Industry Co., Ltd. so that the solid content concentration of paint C became 1% by weight. Furthermore, after drying the PET-1 in vacuum at 160°C for 2 hours, it was put into an extruder, melted at 280°C, and extruded through a die nozzle onto a casting drum with a surface temperature of 25°C to produce unstretched Sheet. Then, the sheet is preheated by a heated roller set, and then stretched 3.5 times in the longitudinal direction (MD direction) at a temperature of 90°C, and then cooled by a roller set at a temperature of 25°C to obtain a uniaxial Stretch film. One side uses a clamp to hold the two ends of the obtained uniaxially stretched film, and the other side stretches 4.0 times in the width direction (TD direction) at right angles to the longitudinal direction of the heating zone at a temperature of 110°C in the tenter. Furthermore, the heat treatment area in the tenter frame was heat-fixed for 10 seconds at a temperature of 230°C. Then, after uniformly slow cooling in the cooling zone, it was wound up to obtain a film with a thickness of 30 μm. On one side of the obtained film, use Coating Agent C-1 to coat with a gravure coater so that the coating thickness after drying becomes 0.1 μm, and dry and harden at 100°C for 20 seconds, whereby the laminate has infrared rays A layer of absorbent and release agent to obtain a film. The characteristics are shown in the table. It can be seen that the contact angle of water is slightly larger, and the number of shrinkage tends to increase slightly in the coating properties of the dielectric paste. In addition, it can be seen that the evaluation of the removability of the release layer is the same as in Example 9 except that the element concentration measurement by XPS (X-ray photoelectron spectroscopy) in the item (F-1) is changed to fluorine. Implemented in the same way, there is no problem with the removability of the release layer.

(Example 13) After the PET-B was vacuum dried at 160°C for 2 hours, it was put into an extruder, melted at 280°C, and extruded through a die nozzle onto a casting drum with a surface temperature of 25°C to produce an unstretched sheet. . Then, the sheet is preheated by a heated roller set, and then stretched 3.5 times in the longitudinal direction (MD direction) at a temperature of 90°C, and then cooled by a roller set at a temperature of 25°C to obtain a uniaxial Stretch film. One side uses a clamp to hold the two ends of the obtained uniaxially stretched film, and the other side stretches 4.0 times in the width direction (TD direction) at right angles to the longitudinal direction of the heating zone at a temperature of 110°C in the tenter. Furthermore, the heat treatment area in the tenter frame was heat-fixed for 10 seconds at a temperature of 230°C. Then, after uniformly slow cooling in the cooling zone, it was wound up to obtain a 30 μm thick film with an infrared absorber. On one side of the obtained film, use Coating Agent A to coat with a gravure coater so that the coating thickness after drying becomes 0.1 μm, and dry and harden at 100°C for 20 seconds, thereby laminating a release layer. Obtain the film. The characteristics are shown in the table. In addition, the evaluation of the removability of the release layer was carried out in the same manner as in Example 9. It can be seen that because the polyester film as the base layer also contains an infrared absorber, the laser light is absorbed by the polyester film as a whole, and the energy is dispersed. Therefore, it is a film with a slightly poorer removability of the release layer.

(Example 14) Put TF850H made by Prime Polymer as a polypropylene resin into the extruder, melt it at 240°C, and extrude it through a die nozzle onto a casting drum with a surface temperature of 25°C to produce an unstretched sheet material. Then, the sheet is preheated by a heated roller set, and then stretched 4.3 times in the longitudinal direction (MD direction) at a temperature of 125°C, and then cooled by a roller set at a temperature of 25°C to obtain a uniaxial Stretch film. On one side, the two ends of the obtained uniaxially stretched film are held by a clamp, and on the other side, the heating zone at a temperature of 160°C in the tenter extends 5.0 times in the width direction (TD direction) at right angles to the longitudinal direction. Then continue to heat fixation in the heat treatment zone in the tenter at a temperature of 140°C for 10 seconds. Then, after uniformly slow cooling in the cooling zone, it was wound up to obtain a film with a thickness of 30 μm. Use coating agent a-1 on one side of the obtained film, apply it with a bar coater so that the coating thickness after drying becomes 0.1 μm, and dry and harden at 100°C for 60 seconds to obtain A polypropylene film as a base layer is laminated with a film having a layer with an infrared absorber with a thickness of 0.1 μm. On the surface of the film obtained with the infrared absorber layer, use Coating Agent A to coat with a gravure coater so that the coating thickness after drying becomes 0.1 μm, and dry and harden at 100°C for 20 seconds. This obtains a film laminated with a release layer. The characteristics are shown in the table. Although the operability is poor due to the low melting point and the peelability of the dielectric paste is slightly poor, it is a film that is practically no problem.

In addition, the removability of the release layer was evaluated in accordance with item F. That is, the blank produced in accordance with item D. is peeled off into a size of 10 cm×10 cm, and the part is irradiated with a continuous wave laser light with a wavelength of 1064 nm and an intensity of 20 W, and then the Si element content or water contact is measured The corners of the mold were evaluated for the remaining of the release layer. The laser device uses the laser marker MDX1500 manufactured by Keynes. Since the amount of Si element as a component of the release agent is relatively small, and the contact angle with water is also less than 90°C, it is a film with excellent release layer removability.

(Example 15) The polyphenylene sulfide (PPS) film "TORELINA" (registered trademark) (30 μm) manufactured by Toray Co., Ltd. is used on one side of coating agent a-1 so that the coating thickness after drying becomes 0.1 μm. The coating was carried out with a bar coater, and dried and cured at 200°C for 40 seconds, thereby obtaining a film in which a layer with an infrared absorber having a thickness of 0.1 μm was laminated on a PPS film as a base layer. On the surface of the obtained film with infrared absorber layer, use Coating Agent A to coat with a gravure coater so that the coating thickness after drying becomes 0.1 μm, dry and harden at 100°C for 20 seconds, and then Obtain a laminated film with a release layer. The characteristics are shown in the table. It is a film with no problems in the coating and peeling properties of the dielectric paste.

In addition, the removability of the release layer was evaluated in accordance with item F. That is, the blank produced in accordance with item D. is peeled off into a size of 10 cm×10 cm, and the part is irradiated with continuous wave laser light with a wavelength of 1064 nm and an intensity of 20 W, and then the content of Si element or the contact with water is measured. The corners of the mold were evaluated for the remaining of the release layer. The laser device uses the laser marker MDX1500 manufactured by Keynes. Since the amount of Si element as a component of the release agent is small, and the contact angle with water is less than 90°C, it is a film with excellent release layer removability.

(Example 17) After the PET-1 was vacuum dried at 160°C for 2 hours, it was put into an extruder, melted at 280°C, and extruded through a die nozzle onto a casting drum with a surface temperature of 25°C to produce an unstretched sheet. . Then, the sheet is preheated by a heated roller set, and then stretched 3.5 times in the longitudinal direction (MD direction) at a temperature of 90°C, and then cooled by a roller set at a temperature of 25°C to obtain a uniaxial Stretch film. One side uses a clamp to hold the two ends of the obtained uniaxially stretched film, and the other side stretches 4.0 times in the width direction (TD direction) at right angles to the longitudinal direction of the heating zone at a temperature of 110°C in the tenter. Furthermore, the heat treatment area in the tenter frame was heat-fixed for 10 seconds at a temperature of 230°C. Then, after uniformly slow cooling in the cooling zone, it was wound up to obtain a film with a thickness of 30 μm. On one side of the obtained film, use coating agent D to coat with a gravure coater so that the coating thickness after drying becomes 0.3 μm, and dry and harden at 100°C for 20 seconds, thereby obtaining a substrate layer And the film of the infrared absorbing layer. Furthermore, in order to contact the infrared absorbing layer of the film having an infrared absorbing layer, the coating agent A was used in the same manner as in Example 1, and the release layer was applied by the gravure coating method to obtain a release layer having a release layer. film. The characteristics are shown in the table. Regarding the removability of the release layer, it was implemented in the same manner as in Example 1. It can be seen that although the film of Example 17 does not show a clear peak (maximum value) in the band of wavelengths above 800 nm and below 1200 nm, the average absorbance at wavelengths above 800 nm and below 1200 nm is relatively high, and the infrared absorber It is contained in the same layer as the release agent, so it is easy to react, and it is a film with excellent removability of the release layer.

(Examples 18, 19) In Examples 18 and 19, FDN-010 (Vanadium Phthalocyanine, Vanadium Phthalocyanine) manufactured by Yamada Chemical Industry Co., Ltd., which is an infrared absorber, was added to Paint E so as to have the concentration shown in the table. 340° C.) instead of the coating agent D of Example 17, and otherwise in the same manner as in Example 17, a film having a layer (release layer) containing an infrared absorber content and a release agent was obtained. The characteristics are shown in the table.

In addition, the removability of the release layer was implemented in the same manner as in Example 1. It can be seen that since the infrared absorber and the release agent are contained in the same layer, they are easy to react, and it is a film with excellent removability of the release layer.

(Example 20) In Example 20, when removing the film release layer produced in Example 17, a pulse wave laser was used instead of a continuous wave laser. Specifically, the laser device uses a laser marker MDX1500 manufactured by Keynes Co., Ltd., and irradiates the laser light by oscillating the laser light with a wavelength of 1064 nm, an output power of 20 W, and a frequency of 200 kHz. The characteristics are shown in the table. It is a film with excellent removability of the release layer.

(Comparative example 1) After the PET-1 was vacuum dried at 160°C for 2 hours, it was put into an extruder, melted at 280°C, and extruded through a die nozzle onto a casting drum with a surface temperature of 25°C to produce an unstretched sheet. . Then, the sheet is preheated by a heated roller set, and then stretched 3.5 times in the longitudinal direction (MD direction) at a temperature of 90°C, and then cooled by a roller set at a temperature of 25°C to obtain a uniaxial Stretch film. After the coating agent a is stretched and dried to a thickness of 0.1 μm by using a Meyer rod to apply to the obtained uniaxially stretched film, the two ends of the film are held by a clamp while the film is held at 110 in the tenter. The heating zone at a temperature of ℃ extends 4.0 times along the width direction (TD direction) at right angles to the longitudinal direction. Furthermore, the heat treatment area in the tenter frame was heat-fixed for 10 seconds at a temperature of 230°C. Then, after uniformly slow cooling in the cooling zone, it was wound up to obtain a film with a thickness of 30 μm. On one side of the obtained film, further use Coating Agent A to coat with a gravure coater so that the coating thickness after drying becomes 0.1 μm, and dry and harden at 100°C for 20 seconds, thereby laminating the release layer And a thin film is obtained. The characteristics are shown in the table. It is a thin film with no absorption peak at a wavelength above 800 nm and below 1200 nm, and a low average absorbance at a wavelength above 800 nm and below 1200 nm.

In addition, the evaluation of the removability of the release layer was carried out in the same manner as in Example 1, but since it did not contain an infrared absorber, there was no absorption peak at a wavelength of 800 nm or more and 1200 nm or less, and the wavelength was 800 A thin film with a low average absorbance between nm and 1200 nm, so the removal of the release layer is not excellent.

(Comparative example 2) After the PET-1 was vacuum dried at 160°C for 2 hours, it was put into an extruder, melted at 280°C, and extruded through a die nozzle onto a casting drum with a surface temperature of 25°C to produce an unstretched sheet. . Then, the sheet is preheated by a heated roller set, and then stretched 3.5 times in the longitudinal direction (MD direction) at a temperature of 90°C, and then cooled by a roller set at a temperature of 25°C to obtain a uniaxial Stretch film. On one side, both ends of the obtained uniaxially stretched film are held by a clamp, and on the other side, the heating area at a temperature of 110°C extends 4.0 times in the width direction (TD direction) at right angles to the longitudinal direction. Furthermore, the heat treatment area in the tenter frame was heat-fixed for 10 seconds at a temperature of 230°C. Then, after uniformly slow cooling in the cooling zone, it was wound up to obtain a film with a thickness of 30 μm. On one side of the obtained film, use Coating Agent A to coat with a gravure coater so that the coating thickness after drying becomes 0.1 μm, and dry and harden at 100°C for 20 seconds, thereby laminating a release layer. Obtain the film. The characteristics are shown in the table. It is a thin film with no absorption peak at a wavelength above 800 nm and below 1200 nm, and a low average absorbance at a wavelength above 800 nm and below 1200 nm.

In addition, the evaluation of the removability of the release layer was carried out in the same manner as in Example 1, but since it did not contain an infrared absorber, there was no absorption peak at a wavelength of 800 nm or more and 1200 nm or less, and the wavelength was 800 A thin film with a low average absorbance between nm and 1200 nm, so the removal of the release layer is not excellent.

(Comparative example 3) After the PET-A was vacuum dried at 160°C for 2 hours, it was put into an extruder, melted at 280°C, and extruded through a die nozzle onto a casting drum with a surface temperature of 25°C to produce an unstretched sheet . Then, the sheet is preheated by a heated roller set, and then stretched 3.5 times in the longitudinal direction (MD direction) at a temperature of 90°C, and then cooled by a roller set at a temperature of 25°C to obtain a uniaxial Stretch film. One side uses a clamp to hold the two ends of the obtained uniaxially stretched film, and the other side stretches 4.0 times in the width direction (TD direction) at right angles to the longitudinal direction of the heating zone at a temperature of 110°C in the tenter. Furthermore, the heat treatment area in the tenter frame was heat-fixed for 10 seconds at a temperature of 230°C. Then, after uniformly slow cooling in the cooling zone, it was wound up to obtain a film with a thickness of 30 μm. On one side of the obtained film, use Coating Agent A to coat with a gravure coater so that the coating thickness after drying becomes 0.1 μm, and dry and harden at 100°C for 20 seconds, thereby laminating a release layer. Obtain the film. The characteristics are shown in the table. It is a thin film with low infrared absorber content, no absorption peak at wavelengths above 800 nm and below 1200 nm, and low average absorbance at wavelengths above 800 nm and below 1200 nm.

In addition, the evaluation of the removability of the mold release layer was carried out in the same manner as in Example 1, but because there was no absorption peak at the wavelength of 800 nm or more and 1200 nm or less, and the average light absorption of the wavelength of 800 nm or more and 1200 nm or less A film with a lower rate, so the removal of the release layer is not excellent.

(Comparative Example 4) Although PET-C was vacuum-dried at 160°C for 2 hours, put into an extruder, melted at 280°C, and extruded through a die nozzle onto a casting drum with a surface temperature of 25°C, but due to infrared absorption The content of the agent is large, and the melt viscosity of the raw material is low, so it is impossible to obtain a sheet.

(Comparative Example 5) The release film provided with the release layer produced in Comparative Example 2 was wound into a roll, and the film feeding device and the winding device, and the cleaning brush set in the middle were used at a speed of 15 m/min on one side Roll out and peel off the release layer on one side. The cleaning brush set in the middle uses a stainless steel wire with a wire diameter of 0.1 mm and a pile length of 15 mm processed into a brush with an outer diameter of 180 mm. The support roller when the brush is in contact with the film is a free roller plated with hard chrome.

Shows the film characteristics after removal. It can be seen that the surface of the film is rough, so although the contact angle with water becomes slightly smaller, the element concentration of Si is higher, and the removal of the release layer is not sufficient.

[Table 1] [Table 1] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Substrate Substrate composition PET-1 PET-1 PET-1 PET-1 PET-1 PET-1 PET-1 PET-1 Tm(℃) 255 255 255 255 255 255 255 255 Average absorbance of wavelength above 800 nm and below 1200 nm (%) 8 8 8 8 8 8 8 8 Thickness (μm) 30 30 30 30 30 30 30 30 Layer containing infrared absorber Infrared absorber 1 Phthalocyanine vanadium Phthalocyanine vanadium Phthalocyanine vanadium Phthalocyanine vanadium Carbon black Copper Phthalocyanine Phthalocyanine vanadium Phthalocyanine vanadium Infrared absorber 2 - - - - - - Copper Phthalocyanine - Main components Acrylic Acrylic Acrylic Acrylic Acrylic Acrylic Acrylic Acrylic Concentration of infrared absorber relative to main constituents (wt%) 1 3 3 3 5 3 2 3 Thickness (μm) 0.1 0.1 0.3 0.3 0.1 0.1 0.1 0.1 Release layer composition Polysiloxane Polysiloxane Polysiloxane Polysiloxane Polysiloxane Polysiloxane Polysiloxane Polysiloxane Thickness (μm) 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1

) 100 100 100 100 100 100 100 100 介電膏 塗佈性 針孔個數 1 2 2 2 3 1 1 2 評價 A A A A A A A A 介電膏 剝離性 剝離力(mN/50 mm) 25 25 25 25 25 25 25 28 評價 A A A A A A A A 脫模層去 除條件、 去除後之 薄膜特性 雷射光 波長(nm) 1064 1064 1064 1064 1064 800 1064 800 1064 強度(W) 20 20 20 10 20 20 20 20 脫模層 之去除 性 元素 Si Si Si Si Si Si Si Si Si殘留(原子%) 15 11 5 7 14 11 4 11 殘留評價 C B A A B B A B 脫模層側之與水之接觸角(

) 88 81 75 75 83 80 74 81 接觸角評價 B B A A B B A B [Table 2] [Table 2] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 film Absorption peak (nm) 1014 1014 1014 1014 - 853 1014/ 853 1014 Peak of absorption peak (%) 12 17 17 17 - 17 16/16 17 Average absorbance of wavelength above 800 nm and below 1200 nm (%) - - - - 35 - - - The contact angle of the release layer side with water (

) 100 100 100 100 100 100 100 100 Dielectric paste coatability Number of pinholes 1 2 2 2 3 1 1 2 Evaluation A A A A A A A A Dielectric paste peelability Peeling force (mN/50 mm) 25 25 25 25 25 25 25 28 Evaluation A A A A A A A A Removal condition of release layer, film characteristics after removal laser Wavelength (nm) 1064 1064 1064 1064 1064 800 1064 800 1064 Strength (W) 20 20 20 10 20 20 20 20 Removability of release layer element Si Si Si Si Si Si Si Si Si residue (atomic %) 15 11 5 7 14 11 4 11 Residue evaluation C B A A B B A B The contact angle of the release layer side with water (

) 88 81 75 75 83 80 74 81 Contact angle evaluation B B A A B B A B

[table 3] [table 3] Example 9 Example 10 Example 11 Example 12 Example 13 Example 14 Example 15 Substrate Substrate composition PET-1 PET-1 PET-1 PET-1 PET-B PP PPS Tm(℃) 255 255 255 255 251 160 280 Average absorbance of wavelength above 800 nm and below 1200 nm (%) 8 8 8 8 13 18 15 Thickness (μm) 30 30 30 30 30 30 30 Layer containing infrared absorber Infrared absorber 1 Phthalocyanine vanadium Phthalocyanine vanadium Phthalocyanine vanadium Phthalocyanine vanadium - Phthalocyanine vanadium Phthalocyanine vanadium Infrared absorber 2 - - - - - - - Main components Polysiloxane Polysiloxane Polysiloxane fluorine Polysiloxane Acrylic Acrylic Concentration of infrared absorber relative to main constituents (wt%) 3 8 8 3 - 3 3 Thickness (μm) 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Release layer composition Integrate with the layer containing infrared absorber Polysiloxane Polysiloxane Thickness (μm) 0.1 0.1

) 75 74 75 75 90 86 83 評價 A A A A C B B [Table 4] [Table 4] Example 9 Example 10 Example 11 Example 12 Example 13 Example 14 Example 15 film Absorption peak (nm) 1014 1014 1014 1014 1014 1014 1014 Peak of absorption peak (%) 17 26 26 14 30 17 17 Average absorbance of wavelength above 800 nm and below 1200 nm (%) - - - - - - - The contact angle between the side of the release layer and the water (°) 100 100 100 110 100 100 100 Dielectric paste coatability Number of pinholes 2 1 3 9 1 2 2 Evaluation A A A B A A A Dielectric paste peelability Peeling force (mN/50 mm) 26 25 twenty four 11 25 33 25 Evaluation A A A A A B A Removal conditions of release layer, film characteristics after removal laser Wavelength (nm) 1064 1064 1064 1064 1064 1064 1064 Strength (W) 20 20 10 10 40 20 20 Removability of release layer element Si Si Si F Si Si Si Residual (atomic %) 8 4 5 F residue: 8 18 15 13 Evaluation A A A A C B B The contact angle of the release layer side with water (

) 75 74 75 75 90 86 83 Evaluation A A A A C B B

[table 5] [table 5] Example 16 Example 17 Example 18 Example 19 Example 20 Substrate Substrate composition PET-1 PET-1 PET-1 PET-1 PET-1 Tm(℃) 255 255 255 255 255 Average absorbance of wavelength above 800 nm and below 1200 nm (%) 8 8 8 8 8 Thickness (μm) 20 30 30 30 30 Layer containing infrared absorber Infrared absorber 1 Phthalocyanine vanadium Carbon black Phthalocyanine vanadium Phthalocyanine vanadium Carbon black Infrared absorber 2 - - - - - Main components Acrylic Epoxy resin Epoxy resin Epoxy resin Epoxy resin Concentration of infrared absorber relative to main constituents (wt%) 3 2 3 5 2 Thickness (μm) 0.3 0.3 0.3 0.3 0.3 Release layer composition Polysiloxane Polysiloxane Polysiloxane Polysiloxane Polysiloxane Thickness (μm) 0.1 0.1 0.1 0.1 0.1

) 100 100 100 100 100 介電膏塗佈性 針孔個數 2 2 2 2 2 評價 A A A A A 介電膏剝離性 剝離力 (mN/50 mm) 21 21 21 21 21 評價 A A A A A 脫模層去除條件、 去除後之薄膜特性 雷射光 波長(nm) 1064 1064 1064 1064 1064 強度(W) 20 20 20 20 20 脫模層之去除性 元素 Si Si Si Si Si 殘留(原子%) 5 3 3 1 9 評價 A A A A A 脫模層側之與水之接觸角(

) 75 75 75 75 75 評價 A A A A A [Table 6] [Table 6] Example 16 Example 17 Example 18 Example 19 Example 20 film Absorption peak (nm) 1014 - 1014 1014 - Peak of absorption peak (%) 17 - 17 28 - Average absorbance of wavelength above 800 nm and below 1200 nm (%) - 40 - - 40 The contact angle of the release layer side with water (

) 100 100 100 100 100 Dielectric paste coatability Number of pinholes 2 2 2 2 2 Evaluation A A A A A Dielectric paste peelability Peeling force (mN/50 mm) twenty one twenty one twenty one twenty one twenty one Evaluation A A A A A Removal condition of release layer, film characteristics after removal laser Wavelength (nm) 1064 1064 1064 1064 1064 Strength (W) 20 20 20 20 20 Removability of release layer element Si Si Si Si Si Residual (atomic %) 5 3 3 1 9 Evaluation A A A A A The contact angle of the release layer side with water (

) 75 75 75 75 75 Evaluation A A A A A

[Table 7] [Table 7] Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 Comparative example 5 Substrate Substrate composition PET-1 PET-1 PET-A PET-C PET-1 Tm(℃) 255 255 253 250 255 Average absorbance of wavelength above 800 nm and below 1200 nm (%) 8 8 9 - 8 Thickness (μm) 30 30 30 - 30 Layer containing infrared absorber Infrared absorber 1 - - - - - Infrared absorber 2 - - - - - Main components Acrylic Polysiloxane Polysiloxane - Polysiloxane Concentration of infrared absorber relative to main constituents (wt%) - - - - - Thickness (μm) 0.1 0.1 0.1 - 0.1 Release layer composition - - - - - Thickness (μm) - - - - -

) 100 100 100 - 100 介電膏塗佈性 針孔個數 1 1 1 - 1 評價 A A A - A 介電膏剝離性 剝離力 (mN/50 mm) 25 25 25 - 25 評價 A A A - A 脫模層去除條 件、去除後之 薄膜特性 雷射光 波長(nm) 1064 1064 1064 - - 強度(W) 40 40 40 - - 脫模層之去除性 元素 Si Si Si - Si 殘留(原子%) 25 25 25 - 22 評價 D D D - D 脫模層側之與水之接觸角(

) 105 105 105 - 81 評價 D D D - B (產業上之可利用性)[Table 8] [Table 8] Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 Comparative example 5 film Absorption peak (nm) - - - - - Peak of absorption peak (%) - - - - - Average absorbance of wavelength above 800 nm and below 1200 nm (%) 8 8 9 - 8 The contact angle of the release layer side with water (

) 100 100 100 - 100 Dielectric paste coatability Number of pinholes 1 1 1 - 1 Evaluation A A A - A Dielectric paste peelability Peeling force (mN/50 mm) 25 25 25 - 25 Evaluation A A A - A Removal conditions of release layer, film characteristics after removal laser Wavelength (nm) 1064 1064 1064 - - Strength (W) 40 40 40 - - Removability of release layer element Si Si Si - Si Residual (atomic %) 25 25 25 - twenty two Evaluation D D D - D The contact angle of the release layer side with water (

) 105 105 105 - 81 Evaluation D D D - B (Industrial availability)

Since the film of the present invention is excellent in mold release properties, particularly in the coating properties and peelability of the dielectric paste, it can be suitably used as a film for the manufacturing step of multilayer ceramic capacitors (MLCC). In addition, the release layer can be easily removed after the film of the present invention is used in the MLCC manufacturing process or the like, so it is possible to easily manufacture the recovered film from which the release layer is removed.

Claims (17)

A film with a thickness of 500 μm or less, and an absorption peak with an absorbance of 10% or more at the top of the peak at a wavelength above 800 nm and below 1200 nm, or an average absorbance with a wavelength above 800 nm and below 1200 nm 15% or more. Such as the film of claim 1, wherein the contact angle between at least one side surface and water is 90° or more. The film of claim 1 or 2, which has a layer (substrate layer) mainly composed of a thermoplastic resin having a melting point of 250° C. or higher, and a layer containing an infrared absorber. The film of claim 3, wherein the infrared absorber has sublimation properties. The film of claim 4, wherein the sublimation temperature of the infrared absorber is 280°C or more and 400°C or less. The film according to any one of claims 3 to 5, wherein the infrared absorber has a phthalocyanine skeleton. The film according to any one of claims 3 to 6, wherein the substrate layer is a layer mainly composed of polyester. Such as the film of any one of claims 1 to 7, which is used for demolding purposes. Such as any one of Claims 1 to 8, which is used for the following purposes: a release layer is provided on the above-mentioned film, and then a release object is provided on the release layer of the film with the release layer, and then the quilt The release object is demolded from the film having the release layer containing the release object, and then the residue of the release object and the release layer are removed from the film having the release layer of the release object. The film of claim 9, wherein the above-mentioned film having a release layer from which the release object has been released is used to remove the residue of the release object and the release layer by irradiating at a wavelength of 800 nm or more and 1200 nm or less Implemented with a laser with an oscillating wavelength. A method of using a film, which is the method of using a film in any one of Claims 1 to 10, including: The step of disposing a release layer on the film; The step of arranging the release object on the release layer of the film with the release layer; The step of demolding the mold-released object from the film having the mold-releasing layer containing the mold-released object; and The step of removing the residue of the mold-releasing object and the mold-releasing layer from the film having the mold-releasing layer of the mold-releasing object. A manufacturing method of recycled film, which is a manufacturing method of recycled film using any one of claims 1 to 10, and includes: The step of setting a release layer on the film of any one of claims 1 to 10; The step of arranging the release object on the release layer of the film with the release layer; The step of demolding the mold-released object from the film having the mold-releasing layer containing the mold-released object; and The step of removing the residue of the demolded object and the demolding layer from the film having the demolded release layer of the demolded object. The film according to any one of claims 3 to 8, wherein the layer containing the infrared absorber has a release agent. For example, the film of claim 13, which is used for the following purposes: set a release object on the above-mentioned film, then release the release object from the film with the release object, and then release the release object from the film. The release film removes the residue of the release object and the layer containing infrared absorber. The film of claim 14, wherein the above-mentioned film from which the mold has been demolded removes the residue of the mold release and the layer containing the infrared absorber by irradiating the film with a wavelength of 800 nm or more and 1200 nm or less with oscillation Laser of wavelength is implemented. A method of using film, which is the method of using film in any one of Claims 13 to 15, including: The step of setting the release object on the film; The step of demolding the demolded object from the film with the demolded object; and The step of removing the residue of the released object and the layer containing the infrared absorber from the released film of the released object. A method for manufacturing a recycled film, which is a method for manufacturing a recycled film using the film of any one of claims 13 to 15, comprising: Steps of setting the release object on the film of any one of Claims 13 to 15; The step of demolding the demolded object from the film with the demolded object; and The step of removing the residue of the released object and the layer containing the infrared absorber from the released film of the released object.