JP3774982B2 - Release film - Google Patents

Description

比較例２〜４
実施例１において、プライマー層用塗布剤１の代わりにポリエステル系樹脂１００部（比較例２）、ポリウレタン系樹脂１００部（比較例３）、ポリエステル系樹脂３５部およびポリウレタン系樹脂６５部（比較例４）、のそれぞれ１０重量％の水分散液を調整し塗布する以外は実施例１と同様にしてプライマー塗布された微細気泡含有ポリエステルフィルムを得た。得られたポリエステルフィルムは、塗布層と微細気泡含有ポリエステルフィルムとがブロッキングを起こし塗布層が微細気泡含有ポリエステルフィルムへ転着し、硬化性シリコーン樹脂の塗布まで至らなかった。
【００４９】
比較例５
実施例１において、プライマー層用塗布剤１の代わりにポリアクリレート系樹脂１００部の１０重量％水分散液を調整し塗布する以外は実施例１と同様にして離型フィルムを得た。得られたフィルムは剥離力の変動が大きく不均一なものであった。
【００５０】
比較例６
実施例１において、プライマー層用塗布剤１をプライマー層用塗布剤５に変更する以外は実施例１と同様にしてプライマー塗布された微細気泡含有ポリエステルフィルムを得た。得られたフィルムのプライマー層は凝集が激しく、表面が粗面化した状態であった。次に、実施例１と同様にして離型フィルムを得たが得られたフィルムは、剥離力の変動が大きく不均一なものであった。
【００５１】
【発明の効果】
本発明の離型フィルムは、微細気泡含有ポリエステルフィルムと硬化シリコーン樹脂塗膜との経時密着性および離型性に優れ、各種の離型フィルムとして使用された場合に、特に印刷等が施される離型フィルムとして使用された場合に、極めて有用である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a release film, and in particular, relates to a release film excellent in adhesiveness with time and adhesion between a microbubble-containing polyester film and a cured silicone resin coating film and an adhesive. More specifically, the present invention is a release film suitable for a release film for electronic seal photography and the like, and is thermally transferred to the substrate surface via an adhesive laminated on the back surface of the release film or on the release layer side. The present invention relates to a release film that can provide a clear image or the like due to its cushioning properties when printed by a law or the like.
[0002]
[Prior art]
Conventionally, various release films coated with a silicone resin for protecting an adhesive surface such as an adhesive have been developed. Japanese Patent Application Laid-Open No. 47-34447 discloses a silicone that cures by a condensation reaction. A resin composition, Japanese Examined Patent Publication No. 52-40918, describes a silicone releasable film that cures by an addition reaction.
[0003]
The conventional release film is mainly a release film in which a silicone resin coating film having a releasability is formed on a base material such as a polyester film. It is known that the sex is bad. As a method for improving the adhesion with the substrate, for example, in Japanese Patent Application Laid-Open No. 64-5838 and Japanese Patent Application Laid-Open No. 3-120042, an undercoat layer using a silane coupling agent is provided on the polyester surface, A method of providing a release layer thereon is described.
[0004]
However, in the method of providing an undercoat layer using a silane coupling agent on the polyester surface, a part of the silane coupling agent evaporates in the process of providing the undercoat layer, for example, in-line coating or offline coating, and adheres in the process. The problem of depositing occurs. The deposits can sometimes fall into the film and degrade the quality of the film.
[0005]
Japanese Patent Publication No. 62-2986 discloses a method of forming a film comprising a crosslinkable silicone and a silane coupling agent. However, the silicone film consisting of a crosslinkable silicone and a silane coupling agent has the disadvantage that the silicone resin that can be used is limited due to the influence of the added silane coupling agent and the design range as a release film is narrowed. In addition, when the adhesion to the base material is increased, it is difficult to reduce the peeling force.
[0006]
In JP-A-5-25303, the surface of the polyester is changed to a certain range by corona treatment or the like, and a thermosetting silicone resin layer is formed thereon. Is still few. In addition, in order to improve the adhesion between the polyester film and the release layer, there is a method using a non-silicone release layer such as silicone-modified urethane or acrylic resin, but in this case, light release properties cannot be obtained. It is a fact.
[0007]
[Problems to be solved by the invention]
This invention makes it a solution subject to provide the release film excellent in the time-dependent adhesiveness and release property of a microbubble containing polyester film and a cured silicone resin coating film.
[0008]
[Means for Solving the Problems]
In view of the above circumstances, the present inventors have conducted intensive studies on a release film with good release characteristics and improved adhesion between the fine bubble-containing polyester film and the silicone release layer. The inventors have found that this can be realized by providing a specific primer layer on the top and forming a curable silicone resin coating on the primer layer, thereby completing the present invention.
[0009]
  That is, the gist of the present invention is that at least one selected from a water-soluble or water-dispersible polyester-based resin, a water-soluble or water-dispersible polyurethane-based resin, a water-soluble or water-dispersible polyacrylate resin on one surface of the fine-bubble-containing polyester film. A coating agent containing one resin and at least one melamine-based or epoxy-based crosslinking agentApplication amount is 1-10 g / m ² In the rangeProvide the applied primer layer, on the primer layerAddition reaction type with a coating thickness of 0.02 to 0.5 μm after curingIt exists in the release film which provides a silicone release layer.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail.
In the present invention, the polyester is obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol. Examples of the aromatic dicarboxylic acid include terephthalic acid and 2,6-naphthalenedicarboxylic acid, and examples of the aliphatic glycol include ethylene glycol, diethylene glycol, and 1,4-cyclohexanedimethanol. Representative polyesters include polyethylene terephthalate (PET), polyethylene-2,6-naphthalenedicarboxylate (PEN), and the like. Among these, polyethylene terephthalate (PET) is preferably used in terms of versatility and economy. In the present invention, the polyester used may be a copolyester containing less than 20 mol% of the third component. Examples of the dicarboxylic acid component of the copolymer polyester include isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, and oxycarboxylic acids (for example, P-oxybenzoic acid). 1 type or 2 types or more are mentioned, As a glycol component, 1 type or 2 types or more, such as ethylene glycol, diethylene glycol, propylene glycol, butanediol, 1, 4- cyclohexane dimethanol, neopentyl glycol, etc. are mentioned.
[0011]
In the present invention, the microbubble-containing polyester film is not particularly limited as long as it is a polyester film containing microbubbles. For example, a substantially incompatible thermoplastic resin is melt-dispersed in the polyester. Examples thereof include a microbubble-containing polyester film obtained by film-forming and stretching a polyester that has been formed.
[0012]
Specific examples of the thermoplastic resin substantially incompatible with the above polyester include polyolefins such as polypropylene, polyethylene, polymethylpentene, and polymethylbutene, and thermoplastic resins such as polystyrene and polycarbonate. . Among these, polypropylene is practical in terms of cost and productivity.
[0013]
As said polypropylene, the crystalline polypropylene whose propylene unit is 95 mol% or more normally is used, Preferably the crystalline polypropylene whose 98 mol% or more is a propylene unit is used. Moreover, the melt flow index (MFI) of the polypropylene used is not particularly limited, but is usually in the range of 0.5 to 30 g / 10 minutes, preferably 1 to 15 g / 10 minutes.
[0014]
The content in the microbubble-containing polyester film of the thermoplastic resin substantially incompatible with the polyester is usually 5 to 45% by weight, preferably 5 to 35% by weight, more preferably 10 to 25% by weight. It is a range. When the content is less than 5% by weight, since the amount of bubbles formed in the film is small, the cushioning property is reduced, and the adhesive is laminated on the back surface of the release film or the release layer side. When printing is performed on the substrate surface by a thermal transfer method or the like, a clear image or the like may be difficult to obtain. Moreover, when the said content exceeds 45 weight%, there exists a tendency for it to be easy to fracture | rupture at the time of film forming.
[0015]
The density of the microbubble-containing polyester film is usually 0.4 to 1.3 g / cm.^Three , Preferably 0.55 to 1.2 g / cm^Three , More preferably 0.7 to 1.1 g / cm^Three Range. The density of the film is 0.4 g / cm^Three If it is less than 1, the film tends to be broken at the time of film formation, so that the productivity tends to deteriorate. The density of the film is 1.3 g / cm^Three When it exceeds, there exists a tendency for cushioning properties to be impaired.
[0016]
In the fine bubble-containing polyester film, it is preferable to add a white pigment for the purpose of improving the concealing property and the print sharpness. The white pigment is not particularly limited, but titanium oxide fine particles are preferably used. The average particle diameter of the white pigment is usually 0.05 to 1 μm, preferably 0.05 to 0.7 μm, more preferably 0.05 to 0.5 μm. The content of the white pigment is usually 0.5 to 25% by weight, preferably 1 to 20% by weight, more preferably 2 to 20% by weight. When the content of the white pigment is less than 0.5% by weight, the concealing property may be lowered and the print sharpness may be lowered. Moreover, when content exceeds 25 weight%, there exists a tendency for a fracture | rupture to occur easily at the time of film forming.
[0017]
The method for containing the white pigment in the fine-bubble-containing polyester film is not particularly limited, but first, the raw material in which the white pigment is contained in the polyester raw material is used, and an arbitrary ratio at the time of extrusion. It is preferable to blend and use.
The method of blending the white pigment with the polyester is not particularly limited, and a known method can be adopted. For example, it can be added at any stage of producing the polyester, but it is preferably added as a slurry dispersed in ethylene glycol or the like at the stage of esterification or before the start of the polycondensation reaction after completion of the transesterification reaction, The polycondensation reaction may proceed. Also, a method of blending a slurry of a white pigment dispersed in ethylene glycol or water with a vented kneading extruder and a polyester raw material, or a white pigment and a polyester raw material dried using a kneading extruder. It is performed by the method of blending.
[0018]
In the present invention, the method of blending the incompatible thermoplastic resin with the polyester is not particularly limited, but the dried polyester raw material and the thermoplastic resin substantially incompatible with the polyester are used. Can be contained by subjecting to an extruder.
In the present invention, an additive such as a fluorescent brightening agent, an antioxidant, a thermal stabilizer, a lubricant, an antistatic agent, a dye, and a pigment is added to the polyester or incompatible thermoplastic resin as necessary. May be.
[0019]
The microbubble-containing polyester film in the present invention can be produced according to a conventionally known method as follows.
First, the raw material is melted by an extruder, and an unstretched sheet is obtained by extruding it from a die onto a rotary cooling drum in a sheet form and solidifying by cooling, and then stretching the obtained unstretched sheet in a biaxial direction. Orient.
[0020]
In the above production method, an electrostatic application adhesion method or a liquid application adhesion method is preferably employed in order to improve the adhesion between the unstretched sheet and the rotary cooling drum to improve the flatness of the sheet. In the present invention, both may be used together as necessary.
In the above production method, the unstretched sheet can be stretched as follows, for example. First, stretching is performed in one direction by a roll or tenter type stretching machine. The stretching temperature is usually 70 to 120 ° C., preferably 80 to 110 ° C., and the stretching ratio is usually 2.5 to 7 times, preferably 3.0 to 6 times. Next, stretching is performed in a direction orthogonal to the first-stage stretching direction. The stretching temperature is usually 70 to 120 ° C., preferably 80 to 115 ° C., and the stretching ratio is usually 3.0 to 7 times, preferably 3.5 to 6 times. Subsequently, heat treatment is performed at a temperature of 170 to 250 ° C. under tension or relaxation within 30% to obtain a biaxially stretched film.
[0021]
Examples of water-soluble or water-dispersible polyester resins used in the present invention include JP-B 47-40873, JP-A 50-83497, JP-A 50-121336, and JP-A 52-155640. Polyesters known in the gazette and the like or polyesters based thereon can be used.
For example, as the dicarboxylic acid component of polyester, terephthalic acid, isophthalic acid, 2,5-naphthalenedicarboxylic acid and ester-forming derivatives thereof are used as examples of aromatic dicarboxylic acid, and as examples of aliphatic dicarboxylic acid, Oxybenzoic acid and its ester-forming derivatives are used.
[0022]
Furthermore, as the glycol component of the ester, aliphatic, alicyclic, aromatic diol and the like can be used. Examples thereof include ethylene glycol, 1,4-butanediol, diethylene glycol, triethylene glycol, 1,4-cyclohexanedimethanol. P-xylenediol and the like, and examples of poly (oxyalkylene) glycol include so-called polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and the like.
[0023]
As the polyester, not only the saturated linear polyester composed of the ester-forming component described above but also a polyester composed of a compound having a trivalent or less-valent ester-forming component or a polyester having a reactive unsaturated group can be used.
Examples of water-soluble or water-dispersible polyurethane resins used in the present invention include Japanese Patent Publication No. 42-24194, Japanese Patent Publication No. 46-7720, Japanese Patent Publication No. 46-10193, Japanese Patent Publication No. 49-37839, Known polyurethane resins can be used in Japanese Laid-Open Patent Publication Nos. 50-123197, 53-1226058, 54-138098, and the like.
[0024]
The main components of the polyurethane-forming component are polyisocyanates, polyols, chain extenders, crosslinkers and the like.
Examples of polyisocyanates include tolylene diisocyanate, phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate and the like.
[0025]
Examples of polyols include polyethers such as polyoxyethylene glycol, polyoxypropylene glycol, polyoxytetramethylene glycol, polyethylene adipate, polyethylene-butylene adipate, polyesters such as polycaprolactone, acrylic polyols, castor oil, etc. There is. Examples of chain extenders or crosslinking agents include ethylene glycol, propylene glycol, butanediol, diethylene glycol, trimethylolpropane, hydrazine, ethylenediamine, diethylenetriamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodicyclohexylmethane. There is water.
[0026]
The polyurethane resin is preferably a resin comprising a polyol having a molecular weight of 300 to 20000, a polyisocyanate, a chain extender having a reactive hydrogen atom, a group that reacts with an isocyanate group, and a compound having at least one anionic group.
The anionic group in the polyurethane resin is -SO._Three H, -OSO_Three It is used as lithium salt such as H, -COOH, sodium salt, potassium salt, or magnesium salt. Of these, sulfonate groups are particularly preferred.
[0027]
Examples of water-soluble or water-dispersible polyacrylate resins used in the present invention include JP-A-2-3473, JP-A-2-292376, JP-A-3-143912, JP-A-3-20365, Known polyacrylate resins or polyacrylate resins based thereon can be used as disclosed in JP-A-63-2223018, JP-A-62-212455, JP-A-62-14191, and the like.
[0028]
As a method for producing a polyacrylate resin, for example, an acrylate ester or a methacrylate ester is obtained by transesterification or esterification of methyl alcohol, ethyl alcohol, butyl alcohol, 2-ethylhexyl alcohol or the like with methyl methacrylate or methacrylic acid. These acrylic monomers are appropriately selected and polymerized using a radical initiator such as a peroxide, an azo compound, or a redox type to obtain a polyacrylate resin. At this time, a hydrophilic group is introduced into the resin skeleton to obtain a hydrophilic resin. Some of the acrylic monomers used for these may have a functional group useful for a crosslinking reaction such as a hydroxyl group, a glycidyl group, a carboxyl group, an amino group, a silyl group, and a phosphoric acid group.
[0029]
Examples of the melamine crosslinking agent used in the present invention include methoxymethylated melamine and butoxymethylated melamine which are alkylol or alkoxylated melamine compounds, and those obtained by co-condensing urea or the like with a part of melamine. Can be used. The epoxy-based crosslinking agent used in the present invention may be a compound having an epoxy group having a water solubility or a water solubilization rate of 50% or more.
[0030]
By adding a cross-linking agent, the adhesion, water resistance, solvent resistance and mechanical strength of the coating layer are improved. As a result, the adhesion with the topcoat layer is improved after the topcoat layer is applied. In particular, the melamine-based crosslinking agent has a high curing rate, and it is more effective when used in combination with a curing catalyst such as a protonic acid or an ammonium salt thereof. The amount of the curing agent used is preferably 0.1 to 60% by weight in the dry solid content of the coating film.
[0031]
At least one resin selected from a water-soluble or water-dispersible polyester resin, a water-soluble or water-dispersible polyurethane resin, a water-soluble or water-dispersible polyacrylate resin, and at least one melamine-based or epoxy-based crosslinking agent Any known coating method can be applied as a method of applying the coating agent containing seeds to the fine-bubble-containing polyester film. For example, a rod coating method, a roll coating method, a gravure coating method, a roll brush method, a spray coating method, an air knife coating method, an impregnation method, a curtain coating method and the like can be applied alone or in combination.
[0032]
It is preferable to select these methods as appropriate and apply them to one side or both sides of the polyester film containing fine bubbles before crystal orientation is completed. The polyester film containing fine bubbles before the completion of the crystal orientation is an unstretched film obtained by extruding a raw material from a die of a melt extruder into a sheet on a rotating cooling drum and solidified by cooling. A uniaxially stretched film stretched in any one of the above, a biaxially stretched film before being stretched in a direction perpendicular to the stretching direction of the uniaxially stretched film, and completing orientation crystallization by heat setting. Especially, it is preferable that a coating liquid is apply | coated to a uniaxially stretched film, and it is guide | induced to a tenter and a coating liquid is dried while a microbubble containing polyester film is laterally stretched and heat-set.
[0033]
The solid content concentration of the coating agent is usually 30% by weight or less, preferably 15% by weight or less. The coating amount is 0.5-20 g / m² 1-10 g / m² Is preferred. The coating agent for the microbubble-containing polyester film of the present invention includes, as necessary, a coating property improver, a thickener, a lubricant, polymer particles, inorganic particles, a pigment, a dye, an antioxidant, an ultraviolet absorber, An infrared absorber, an antistatic agent, an antifoaming agent, a foaming agent and the like can be contained. Furthermore, since the coating solution uses water as a medium, it is possible to use a water-soluble resin such as gelatin or polyvinyl alcohol, or an emulsion such as a vinyl resin or an epoxy resin, if necessary.
[0034]
  In the present invention, it is necessary to provide a cured silicone resin coating film on one of the surfaces provided with the primer layer of the microbubble-containing polyester film. The cured silicone resin coating film is a layer that imparts release properties to the film, and is formed by coating a coating liquid containing a curable silicone resin, drying, and curing. As a curable silicone resinWithAdditive reaction typeUse.
[0035]
In the present invention, the curable silicone resin can be coated by a known method such as a reverse roll coating method, a gravure roll coating method, or an air knife coating method.
For example, the applied thermosetting silicone resin is subjected to a heat treatment at a temperature in the range of 50 ° C. to 150 ° C., preferably 80 ° C. to 130 ° C. within 2 minutes, preferably within 1 minute. Can be formed.
[0036]
The application amount of the curable silicone resin is 1 to 25 g / m.² And 2-20 g / m² The thickness of the cured silicone resin coating is preferably 0.01 to 1 μm, more preferably 0.02 to 0.5 μm. When the thickness of the coating film is less than 0.01 μm, the release performance tends to decrease. On the other hand, when the thickness of the coating film exceeds 1 μm, the curing of the coating film becomes insufficient, and the release performance may change over time.
[0037]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless the summary is exceeded. In the examples and comparative examples, “parts” means “parts by weight”.
The measuring method used in the present invention is as follows.
(1) Love-off test
After coating, the sample is left in a room at 23 ° C./50% RH for 30 days, then the coated surface is rubbed several times with a fingertip, and the degree of falling off of the cured silicone film is judged according to the following evaluation criteria. did.
[0038]
[Table 1]
○: No dropout (good adhesion)
Δ: Slightly dropped, but practically no problem
×: Dropped (adhesion failure)
(2) Peel strength test
No. made by Nitto Denko Co., Ltd. on the cured silicone resin coated surface of the release film. A 502 double-sided pressure-sensitive adhesive tape was affixed, pressure-bonded with a linear pressure of 450 g / cm using a rubber roller, cut into a width of 50 mm, and used as a sample for measuring peel force. After the pressure bonding, the sample was allowed to stand for 1 hour, and then peeled off in the 180 ° direction at a tensile speed of 300 mm / min using an Instron type tensile tester, and the average value of the stress was defined as the peeling force of the sample. This test was repeated 10 times, and the arithmetic mean of 10 times was used as the peel force. The atmosphere in which this test was performed is a standard state of 23 ° C./50% RH.
<Production of polyester A for polyester film containing fine bubbles>
100 parts of dimethyl terephthalate, 60 parts of ethylene glycol, and 0.09 part of magnesium acetate tetrahydrate are placed in a reactor, and the temperature is raised while heating and methanol is distilled off. The temperature was raised to 230 ° C. to substantially complete the transesterification reaction. Next, after 0.04 part of ethyl acid phosphate and 0.04 part of antimony trioxide were added, the temperature was 280 ° C. and the pressure was 15 mmHg in 100 minutes, and thereafter the pressure was gradually reduced until finally 0.3 mmHg. did. After 4 hours, the system was returned to normal pressure to obtain polyester.
<Manufacture of polyester B for microbubble-containing polyester film>
85 parts of polyester A and 15 parts of titanium oxide particles having an average particle size of 0.27 μm were dry blended and extruded using a twin-screw kneading extruder to obtain polyester B. The content of titanium oxide in the polyester was 15% by weight.
<Manufacture of polyester C for polyester film containing fine bubbles>
93 parts of polyester A and 7 parts of titanium oxide particles having an average particle size of 0.27 μm were dry blended and extruded using a twin-screw kneading extruder to obtain polyester C. The content of titanium oxide in the obtained polyester was 7% by weight.
<Manufacture of polyester resin>
33.7 parts of dimethyl terephthalate, 20.0 parts of dimethyl isophthalate, 9.1 parts of 3-sodiosulfodimethylisophthalate, 40 parts of ethylene glycol, 10 parts of diethylene glycol, 0.047 part of calcium acetate monohydrate, Transesterification is carried out at 200-230 ° C. until the theoretical amount of methanol is distilled off.
[0039]
Next, 0.09 part of orthophosphoric acid was added, 0.025 part of antimony trioxide was further added, and polymerization was performed at 280 ° C. under reduced pressure. The specific viscosity of the polymer thus obtained was 1.53.
<Manufacture of polyurethane resin>
Polyethers containing sulfonate groups obtained by sulfonation of polyether of ethylene oxide extracted from allyl alcohol with sodium metabisulfite (SO_Three 192 parts by weight, polyethylene oxide content 83% by weight) 192 parts, polytetramethylene adipate (molecular weight 2250) 1013 parts, bisphenol A-initiated polypropylene oxide polyether (molecular weight 550) 248 parts, Dehydrated at 100 ° C. under vacuum. The mixture is brought to 70 ° C., to which is added a mixture of 178 parts of isophorone diisocyanate and 244 parts of hexamethylene-1,6-diisocyanate, and the resulting mixture is then heated from 80 ° C. to 90 ° C. until the isocyanate content is 5.6% by weight. Stir in the range of ° C.
[0040]
The prepolymer was cooled to 60 ° C., and 56 parts of biuret polyisocyanate obtained from 3 moles of hexamethylene diisocyanate and 1 mole of water, and 175 parts of bisketimine obtained from isophoronediamine and acetone were sequentially added.
Water preheated to 50 ° C. in which 15 parts of hydrazine hydrate was dissolved was added to this mixture with vigorous stirring to obtain a polyurethane water dispersion.
<Manufacture of polyacrylate resin>
First, about 20% of a mixture of ethyl acrylate 1320 parts, acrylic acid 95 parts, hydrogen peroxide 9.5% with respect to the monomer, octadecane sulfonic acid soda (14%) 30 parts, water 1800 parts at a low temperature is first 70-80 Polymerization was carried out in a stirrer equipped with a cooler at 80 ° C., and then 80% of the remaining liquid was gradually added over 2 to 3 hours, followed by stirring at 80 to 90 ° C. for 1 to 1.5 hours to complete the polymerization. . At this time, the unreacted monomer was driven off while sending a nitrogen stream to obtain an emulsion.
<Preparation of primer layer coating agent 1>
25 parts of a polyester resin, 65 parts of a polyurethane resin, and 10 parts of a methoxymethylated melamine were weighed out to prepare a primer layer coating composition 1 by adjusting a 10% by weight aqueous dispersion.
<Adjustment of primer layer coating agent 2>
20 parts of a polyester resin, 70 parts of a polyacrylate resin, and 10 parts of a methoxymethylated melamine were weighed out to prepare a primer layer coating agent 2 by adjusting a 10% by weight aqueous dispersion.
<Adjustment of primer layer coating agent 3>
Weigh 20 parts of polyester resin, 50 parts of polyacrylate resin, 10 parts of methoxymethylated melamine, and 20 parts of water-soluble epoxy crosslinking agent, and adjust the 10% by weight aqueous dispersion to prepare primer layer coating composition 3 did.
<Adjustment of primer layer coating agent 4>
50 parts of a polyester resin, 40 parts of a polyurethane resin, and 10 parts of a water-soluble epoxy crosslinking agent were weighed out to prepare a 10% by weight aqueous dispersion, thereby preparing a primer layer coating agent 4.
<Adjustment of primer layer coating 5>
25 parts of polyester resin, 65 parts of polyurethane resin, 10 parts of aziridine crosslinking agent Chemitite PZ-33 (trade name, manufactured by Nippon Shokubai Co., Ltd.) are each weighed and adjusted to a 10% by weight aqueous dispersion for primer layer The coating agent was 5.
[0041]
  Example 1
  A raw material obtained by dry blending 83 parts of polyester B dried in an inert gas atmosphere at 180 ° C. for 4 hours and 17 parts of crystalline polypropylene having a melt flow index (MFI) of 10 g / 10 min at 290 ° C. by a melt extruder. It was melt-extruded and cooled and solidified on a cooling roll having a surface temperature set to 40 ° C. using an electrostatic application adhesion method to obtain an unstretched sheet. The obtained sheet was stretched 3.4 times in the longitudinal direction at 85 ° C. Next, the primer layer coating agent 1 is applied onto a uniaxially stretched film by a roll coating method, and then the film is guided to a tenter and stretched in the transverse direction at 110 ° C. by 3.2 times, followed by heat setting at 230 ° C. A fine bubble-containing polyester film having a thickness of 100 μm coated with a primer layer was obtained. Next, on the microbubble-containing polyester film coated with the primer layerAddition reaction typeUsing a coating solution comprising 100 parts by weight of a curable silicone resin (KS-779 manufactured by Shin-Etsu Chemical Co., Ltd.), 1 part by weight of a curing agent (CAT PL-8 manufactured by Shin-Etsu Chemical Co., Ltd.) and 2200 parts by weight of a methyl ethyl ketone / toluene mixed solvent. The release film on which a cured silicone resin film was formed was applied by an off-line coating method using a roll coating method so that the coating thickness after curing was 0.1 μm.
[0042]
Example 2
In Example 1, a release film was obtained in the same manner as in Example 1 except that polyester B was changed to polyester C.
Example 3
A release film was obtained in the same manner as in Example 1 except that the primer layer coating agent 1 was changed to the primer layer coating agent 2 in Example 1.
[0043]
Example 4
A release film was obtained in the same manner as in Example 1 except that the primer layer coating agent 1 was changed to the primer layer coating agent 3 in Example 1.
Example 5
A release film was obtained in the same manner as in Example 1 except that the primer layer coating agent 1 was changed to the primer layer coating agent 4 in Example 1.
[0044]
Example 6
100 parts by weight of curable silicone resin (KS-723A manufactured by Shin-Etsu Chemical Co., Ltd.), 25 parts of KS-723B manufactured by Shin-Etsu Chemical Co., Ltd. A release film was obtained in the same manner as in Example 1 except that a coating solution composed of 5 parts by weight of CAT PS-3) manufactured by Kogyo Co., Ltd. and 2200 parts by weight of a mixed solvent of methyl ethyl ketone / toluene was used.
[0045]
Example 7
100 parts by weight of curable silicone resin (X-62-5039A manufactured by Shin-Etsu Chemical Co., Ltd.) and 5 weight of curing agent (X-62-5039B manufactured by Shin-Etsu Chemical Co., Ltd.) on the polyester film coated with the primer layer coating agent 1 A release film was obtained in the same manner as in Example 1 except that a coating solution consisting of 2200 parts by weight of a methyl ethyl ketone / toluene mixed solvent was used.
[0046]
Comparative Example 1
The polyester is dried at 180 ° C. for 4 hours in an inert gas atmosphere, melt-extruded at 290 ° C. by a melt extruder, and cooled and solidified on a cooling roll having a surface temperature set to 40 ° C. using an electrostatic application adhesion method. Thus, an unstretched sheet was obtained. The obtained sheet was stretched 3.2 times in the longitudinal direction at 85 ° C. Next, the film was guided to a tenter and stretched transversely at 100 ° C. by 3.2 times, followed by heat setting at 230 ° C. to obtain a 38 μm thick polyester film. The polyester film comprises 100 parts by weight of a curable silicone resin (KS-779 manufactured by Shin-Etsu Chemical Co., Ltd.), 1 part by weight of a curing agent (CAT PL-8 manufactured by Shin-Etsu Chemical Co., Ltd.), and 2200 parts by weight of a methyl ethyl ketone / toluene mixed solvent. Using the coating solution, a release film having a cured silicone resin film formed thereon was applied by an off-line coating method using a roll coating method so that the coating thickness after curing was 0.1 μm.
[0047]
The obtained results are summarized in Table 1 below.
[0048]
[Table 2]

Comparative Examples 2-4
In Example 1, instead of primer layer coating agent 1, 100 parts of polyester resin (Comparative Example 2), 100 parts of polyurethane resin (Comparative Example 3), 35 parts of polyester resin and 65 parts of polyurethane resin (Comparative Example) 4), a fine-bubble-containing polyester film coated with a primer was obtained in the same manner as in Example 1 except that 10% by weight of each aqueous dispersion was prepared and applied. In the obtained polyester film, the coating layer and the microbubble-containing polyester film were blocked, and the coating layer was transferred to the microbubble-containing polyester film, and the curable silicone resin was not applied.
[0049]
Comparative Example 5
In Example 1, a release film was obtained in the same manner as in Example 1 except that a 10 wt% aqueous dispersion of 100 parts of a polyacrylate resin was prepared and applied instead of the primer layer coating agent 1. The obtained film had a large variation in peeling force and was non-uniform.
[0050]
Comparative Example 6
In Example 1, a primer-coated microbubble-containing polyester film was obtained in the same manner as in Example 1 except that the primer layer coating agent 1 was changed to the primer layer coating agent 5. The primer layer of the obtained film was agglomerated and the surface was roughened. Next, a release film was obtained in the same manner as in Example 1, but the obtained film had a large variation in peeling force and was non-uniform.
[0051]
【The invention's effect】
The release film of the present invention is excellent in adhesion and release properties over time between the microbubble-containing polyester film and the cured silicone resin coating film, and is particularly printed when used as various release films. This is extremely useful when used as a release film.

Claims (5)

At least one resin selected from a water-soluble or water-dispersible polyester resin, a water-soluble or water-dispersible polyurethane resin, a water-soluble or water-dispersible polyacrylate resin, and a melamine-based resin on one side of the microbubble-containing polyester film Or the primer layer which apply | coated the coating agent containing at least 1 sort (s) of an epoxy type crosslinking agent in the range whose application quantity is 1-10 g / m < ² > is provided, and the coating-film thickness after hardening is 0 on the said primer layer. A release film provided with an addition reaction type silicone release layer having a thickness of 0.02 to 0.5 μm . The microbubble-containing polyester film contains 5 to 45% by weight of a thermoplastic resin substantially incompatible with polyester and has a density of 0.4 to 1.3 g / cm ³ . Release film.   The release film according to claim 2, wherein the thermoplastic resin substantially incompatible with polyester is polypropylene.   The release film according to any one of claims 1 to 3, wherein the fine-bubble-containing polyester film contains 0.5 to 25% by weight of a white pigment.   The release film according to claim 4, wherein the white pigment is titanium oxide.