JP4313614B2 - Release film - Google Patents

Description

【００７０】
【発明の効果】
本発明によれば、離形フィルム表面の大きな突起が成形シートに転写しない優れた表面特性を有するとともに、加工適性に優れ、シリコーン転写の無い離型フイルムを提供することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a release film.
[0002]
[Prior art]
Release films are used, for example, for resin sheet molding, adhesive release, medical use, and electrical / electronic component manufacturing.
[0003]
In a molded body such as a resin sheet molded from a release film, flattening the surface of the molded body is an important issue. It is no exaggeration to say that the quality of a molded product formed from a film depends on the accuracy and quality of the surface, that is, the accuracy and quality of the surface of the release film (Japanese Patent Laid-Open No. 11-348186). Publication). Furthermore, it has been studied to reduce the transfer of silicone as much as possible for release films used in the production of electric / electronic parts (Japanese Patent Laid-Open No. 11-268194). Unreacted substances cannot be completely removed, and slight transcription occurs. Silicone transferred to the molded part hinders contamination and adhesion in subsequent manufacturing processes, resulting in defects in quality and durability.
[0004]
The release film itself forms a resin layer having releasability on the polyester film. Normally, polyester film is blended with particles to improve processability, for example, slipperiness and winding properties, but generally, the addition of the particles improves handling, but the film surface becomes rough. . If the blending of the particles is stopped in order to avoid this and create a flat surface property, the resulting film will be extremely slippery and air bleed and will not wrinkle or roll in processing. Become.
[0005]
In addition, when the film is accompanied by a release coating layer, the coating layer covers and hides the protrusions on the surface of the polyester film. Conventionally, in a molded body or a molded sheet molded from a release film, there is no strict requirement for the surface characteristics, and even a certain degree of roughness does not cause a quality problem. However, in recent years, the requirements for the surface characteristics of a molded sheet using a release film have become very strict.
[0006]
For example, in the case of a sheet of vinyl chloride resin or urethane resin, these resin solutions are cast on a release film to form a sheet. In these sheets, particularly high gloss may be required on the molding surface.
[0007]
Moreover, in the release film for adhesive tape, since the unevenness of the release film surface is transferred to the surface of the adhesive layer of the adhesive tape, for example, when the adhesive tape is applied to the glass surface, It becomes impossible to get a clean appearance. Therefore, surface flatness is required.
[0008]
Furthermore, release films used as process materials for electronic parts have particularly high demands on surface characteristics. For example, when preparing a thin layer sheet of a ceramic capacitor, a ceramic slurry in which ceramic powder and a binder agent are dispersed in a liquid medium is applied on a release film to form a very thin sheet of 3 μm or less. As the sheet becomes thinner, the surface irregularities of the release film directly lead to an increase in the defective rate of the molded sheet. Also, when used as a process material for display applications, smoothing of the surface of the release film is required by thinning the molded sheet.
[0009]
The release film used in the semiconductor field requires surface flatness, but also considers transfer of silicone as a very problem, and the demand for release film without silicone transfer has become very high. Yes.
[0010]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-348186
[Patent Document 2]
Japanese Patent Laid-Open No. 11-268194
[Problems to be solved by the invention]
An object of the present invention is to solve the drawbacks of the prior art, with a large projection of the releasing film surface has excellent surface characteristics that do not transfer to the molded sheet, excellent processability aptitude, without releasing film of silicone transfer It is to provide.
[0013]
[Means for Solving the Problems]
That is, the present invention, the surface of the port re ester film, a releasing film having a parting layer of 300nm or less in thickness containing fine inert particles, the center line surface roughness Ra of the release layer is 5nm or less The ten-point average roughness Rz is 30 nm or less, and the release layer is composed of a compound containing a long-chain alkyl group and not containing polydimethylsiloxane, and is inactive with the thickness (t [nm]) of the release layer. the average particle diameter of the particles (d [nm]) satisfies the following equation,
0.3d ≦ t ≦ 2.5d
It is a release film in which the relationship between the number of protrusions on the surface of the release film and the protrusion height satisfies the following formula.
HD5 (number of protrusions of 5 nm or more) ≧ 500 pieces / mm ²
HD10 (number of protrusions with a height of 10 nm or more) ≦ 100 / mm ²
[0014]
Hereinafter, the present invention will be described in detail.
[0015]
[Polyester film]
[polyester]
In the present invention, a polyester film is used as the base film. In the present invention, the polyester is a polyester having an aromatic dicarboxylic acid as a main acid component and an aliphatic glycol as a main glycol component. Such polyesters are substantially linear and have film formability, particularly film formability by melt molding.
[0016]
Examples of aromatic dicarboxylic acids include terephthalic acid, naphthalenedicarboxylic acid, isophthalic acid, diphenoxyethanedicarboxylic acid, diphenyldicarboxylic acid, diphenylether dicarboxylic acid, difelsulfone dicarboxylic acid, diphenylketone dicarboxylic acid, and anthracene dicarboxylic acid. Can do.
[0017]
Examples of the aliphatic glycol include polymethylene glycol having 2 to 10 carbon atoms such as ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol and decamethylene glycol, and an alicyclic diol such as cyclohexanedimethanol. Can be mentioned.
[0018]
In the present invention, as the polyester, those mainly comprising alkylene terephthalate or alkylene naphthalate are preferably used.
[0019]
As such polyester, polyethylene terephthalate or polyethylene-2,6-naphthalate is preferable.
[0020]
Polyethylene terephthalate includes a copolymer in which, for example, 80 mol% or more of all dicarboxylic acid components are terephthalic acid, and for example, 80 mol% or more of all glycol components are ethylene glycol.
[0021]
Polyethylene-2,6-naphthalate includes a copolymer in which 80 mol% or more of all dicarboxylic acid components are 2,6-naphthalenedicarboxylic acid and 80 mol% or more of all glycol components are ethylene glycol, for example. Is done.
[0022]
In the case of such a copolymer, 20 mol% or less can be a dicarboxylic acid component other than terephthalic acid or 2,6-naphthalenedicarboxylic acid, and the dicarboxylic acid component is, for example, the above aromatic cigarbonic acid. Can do. Further, for example, it may be an alicyclic dicarboxylic acid such as adipic acid or sebacic acid; an alicyclic dicarboxylic acid such as cyclohexane-1,4-dicarboxylic acid.
[0023]
In addition, 20 mol% or less of the total glycol component can be a glycol component other than ethylene glycol, and the glycol component can be, for example, the above-described glycol, such as hydroquinone, resorcin, 2,2-bis (4-hydroxy). An aromatic diol such as phenyl) propane; an aliphatic diol having an aromatic ring such as 1,4-dihydroxydimethylbenzene; a polyalkylene glycol (polyoxyalkylene glycol) such as polyethylene glycol, polypropylene glycol, polytotetramethylene glycol, etc. Can be.
[0024]
In the polyester of the present invention, a component derived from an oxycarboxylic acid such as an aromatic oxyacid such as hydroxybenzoic acid or an aliphatic oxyacid such as ω-hydroxycaproic acid is used as a dicarboxylic acid component and an oxycarboxylic acid component. Copolymerization or bonding is included in an amount of 20 mol% or less based on the total amount.
[0025]
Further, the polyester contains a tri- or higher functional polycarboxylic acid or polyhydroxy compound such as trimellitic acid or pentaerythritol in an amount within a substantially linear range, for example, an amount of 2 mol% or less based on the total acid component. Copolymerized products are also included.
[0026]
The polyester is known per se and can be produced by a method known per se. The polyester preferably has an intrinsic viscosity of 0.4 to 0.9 determined by measurement at 35 ° C. as a solution in o-chlorophenol.
[0027]
In the present invention, the polyester film may or may not contain inert particles. Inert particles when containing an average particle size of preferably less than 1 [mu] m, more preferably from inert particles less than 1 [mu] m or more 0.01 [mu] m. As the inert particles, either organic particles or inorganic particles can be used, and mixed particles of organic particles and inorganic particles may be used. The inert particles may be formed of two or more components. The ratio of the major axis to the minor axis (major axis / minor axis) of the inert particles of each component is preferably 1.0 to 1.2. By blending these inert particles, very fine irregularities can be formed on the film surface. Specific examples of such inert particles include inorganic particles such as calcium carbonate, kaolin, silicon oxide, barium sulfate, titanium oxide, and alumina oxide; crosslinked polystyrene resin particles, crosslinked silicone resin particles, crosslinked acrylic resin particles, and crosslinked polystyrene resin particles. Organic resin particles such as, for example, may be particles in which an inorganic material and an organic material take the form of a shell core structure.
[0028]
[the film]
In the present invention, the polyester film may be a single layer film or a laminated film. In the case of a laminated film, it can be composed of at least two layers, and is preferably produced by coextrusion. In this case, the polyester constituting the layer may be the same or different, but the same is preferable.
[0029]
In the present invention, when the polyester film is a laminated film, if the types of polyester constituting the film are expressed as A, B, C, for example, a laminated structure of A / B, A / B / A, A / B / C is formed. Can take.
[0030]
As for the surface roughness of at least one side of the polyester film, the center line average roughness Ra is 5 nm or less, and the ten-point average roughness Rz is 30 nm or less. When Ra exceeds 5 nm, the smoothness of the surface is impaired in the thin-layer molded sheet, and when Rz exceeds 30 nm, thickness unevenness occurs in the molded sheet, resulting in poor electrical characteristics in electronic material applications.
[0031]
The total thickness of the polyester film is preferably 10 to 100 μm, more preferably 15 to 50 μm, both in the case of a single layer film and in the case of a laminated film.
[0032]
The polyester film itself can be obtained by a method conventionally known or accumulated in the art. In order to obtain a laminated biaxially oriented film, for example, a polyester unmelted film having an intrinsic viscosity of 0.4 to 0.8 dl / g by melting and co-extruding polyester at a temperature of melting point (Tm: ° C.) to (Tm + 70) ° C. Get. Next, the laminated unstretched film is uniaxially (longitudinal or transverse) at a temperature of (Tg-10) to (Tg + 70) ° C. (where Tg is the glass transition temperature of the polyester) 2.5 times or more, preferably 3 The film is stretched at a magnification of at least twice, and then stretched at a temperature of Tg to (Tg + 70) ° C. in a direction perpendicular to the stretching direction at a magnification of 2.5 times or more, preferably 3 times or more. Furthermore, you may extend | stretch again in the vertical direction and / or a horizontal direction as needed. Thus, the total draw ratio is preferably 9 times or more, more preferably 12 to 35 times, and particularly preferably 15 to 25 times as the area draw ratio. Furthermore, the biaxially oriented film can be heat-set at a temperature of (Tg + 70) ° C. to (Tm−10) ° C. (where Tm is the melting point of polyester), and is preferably 180 to 250 ° C., for example. The heat setting time is preferably 1 to 60 seconds.
[0033]
[Release layer]
[resin]
In the present invention, a release layer is provided on the surface of the polyester film. This release layer is composed of a compound containing a long- chain alkyl group and not containing polydimethylsiloxane. Therefore, the release layer is preferably formed of an organic resin having a long-chain alkyl group without having a polydimethylsilicone component.
[0034]
The organic resin may be either thermosetting or thermoplastic. For example, the main component is a resin such as acrylic, polyester, alkyd, melamine, epoxy, amide, imide, PVA, or a copolymer thereof, and the side chain has a long-chain alkyl group.
[0035]
The long chain alkyl group is preferably an alkyl group having 12 to 28 carbon atoms. If the number of carbon atoms is less than 12, the peeling properties are poor and peeling from the molded article is worsened. If the number of carbon atoms exceeds 28, the solubility of the resin becomes worse and a homogeneous thin film cannot be formed.
[0036]
In the present invention, the release layer can be applied by, for example, applying a coating liquid containing the components of the release layer to the film and drying by heating. As a coating method of this coating liquid, any known coating method can be applied. Examples of applicable coating methods include a roll coater method and a blade coater method. Heat drying for forming the coating layer is preferably performed at 70 to 170 ° C. for 30 to 90 seconds.
[0037]
The thickness of the release layer is 300 nm or less, preferably 30 nm or more and 300 nm or less, and more preferably 50 nm or more and 200 nm or less. When the release layer thickness exceeds 300 nm, blocking tends to occur. If it is less than 30 nm, the peeling properties are not stabilized, and peeling may become heavy, which is not preferable.
[0038]
[Inert fine particles]
The release layer in the present invention contains fine inert particles. The fine inert particles give many fine irregularities on the flat release layer surface, but the shape is so fine that it does not cause a problem even if it is transferred to a molded sheet. Transfer (blocking) and process suitability are improved. In order to satisfy such requirements, the average particle diameter of the inert particles is preferably 1 to 100 nm, more preferably 3 to 80 nm, still more preferably 5 to 80 nm, and further preferably 5 to 50 nm. As the inert particles, either organic particles or inorganic particles can be used, and mixed particles of organic particles and inorganic particles may be used.
[0039]
Specific examples of the inert particles include inorganic particles such as calcium carbonate, kaolin, silicon oxide, barium sulfate, titanium oxide, alumina oxide, magnesium oxide, and zirconium oxide; crosslinked polystyrene resin particles, crosslinked silicone resin particles, and crosslinked acrylic resin particles. , Organic resin particles such as crosslinked polystyrene resin particles can be mentioned, and the inorganic material and the organic material may be particles having a shell core structure.
[0040]
In particular, in the case of fine particles, inorganic particles are preferred, and the ratio of the major axis to minor axis (major axis / minor axis) of the inert particles is preferably 1.0 to 1.2. By blending the inert particles, very fine irregularities can be formed on the surface of the release layer.
[0041]
The addition amount is preferably 0.1 to 25% by weight, more preferably 0.3 to 5%, based on the weight of the release layer. If the amount added is less than 0.1% by weight, slipping or blocking of the release layer occurs, and the release characteristics of the release layer become unstable, and if it exceeds 25% by weight, the transparency is lowered and aggregation is likely to occur. An object is generated, which is not preferable.
[0042]
The surface roughness of the release layer of the release film in the present invention can be appropriately controlled by the resin used for the release layer and the fine particles to be added.
[0043]
Center line surface roughness Ra of the release layer is 5nm or less, ten point average roughness Rz Ru der below 30 nm. When Ra exceeds 5 nm, the smoothness of the surface is impaired in the thin-layer molded sheet, and when Rz exceeds 30 nm, thickness unevenness occurs in the molded sheet, and electrical characteristics are poor in the electronic material application, which is not preferable.
[0044]
The thickness (t [nm]) of the release layer and the average particle diameter (d [nm]) of the inert particles satisfy the following formula.
0.3d ≦ t ≦ 2.5d
[0045]
If the thickness of the release layer is less than 0.3d, particles fall off and cause foreign matter. On the other hand, if it exceeds 2.5 d, fine irregularities on the surface are not formed, resulting in poor sliding properties, and handling, winding properties, and peeling electrification failures occur.
[0046]
In the present invention, fine irregularities of a release film surface, the relationship of the projection speed and the projection height of the surface meet the following equation.
HD5 (number of protrusions of 5 nm or more) ≧ 500 pieces / mm ²
HD10 (number of protrusions with a height of 10 nm or more) ≦ 100 / mm ²
[0047]
When the HD5 is less than 500, slipperiness is poor, and handling, winding property, and peeling electrification failure occur. When the HD10 exceeds 100, the shape is transferred to the surface of the molded sheet, which is not preferable because it causes unevenness in the thickness of the sheet.
[0048]
Various known additives can be blended in the release layer as long as the object of the present invention is not hindered. For example, an ultraviolet absorber, a pigment, an antifoaming agent, a lubricant (talc, clay, alumina, etc.), and an antistatic agent may be added as necessary. In addition to the release layer, the polyester film surface may be coated with a combination of such an additive and a resin.
[0049]
In the present invention, a corona treatment or an adhesive layer may be provided between the polyester film and the release layer in order to enhance the adhesion between the polyester film and the release layer. For this adhesive layer, for example, resins such as polyester, acrylic, and urethane, copolymer resins thereof, or silane coupling agents can be preferably used. The preferable thickness of the adhesive layer is about 0.005 to 0 and 1 μm, and particularly preferably 0.01 to 0.1 μm. When the thickness of the adhesive layer is within the above range, the adhesion between the polyester film and the release layer is improved.
[0050]
【Example】
Hereinafter, the present invention will be further described with reference to examples.
Each characteristic value of the film was measured by the following method.
[0051]
(1) Average particle diameter (d)
Measured using a CP-50 Centrifuggle Particle Size Analyzer (Shimadzu Corporation). The particle size corresponding to 50 mass percent is read from the integrated curve of the particles of each particle size calculated based on the obtained centrifugal sedimentation curve and the abundance thereof, and this value is taken as the average particle size (Book “particle size measurement”). Technology ", published by Nikkan Kogyo Shimbun, 1975, pages 242-247).
[0052]
(2) Centerline average roughness (Ra (nm))
The center line average roughness (Ra) is a value defined by JIS-B0601, and in the present invention, it is measured using a non-contact type surface roughness meter of WYKO CORPORATION NT-2000. The measurement conditions are as follows.
(A) Measurement area: 0.0462 μm
(B) Measurement magnification: 25 times
(3) Ten-point average roughness Rz (nm)
The ten-point average roughness (Rz) is a value defined by JIS-B0601 and is measured by the same model as the centerline average roughness Ra measurement in the present invention. In the part extracted by the reference length from the cross-sectional curve of the obtained data, the value of the difference between the average value of the altitude at the top of the fifth peak and the average value of the altitude at the bottom of the valley from the deepest to the fifth is shown.
[0054]
(4) HD5 and HD10
HD5 and HD10 are measured by the same model as the centerline average roughness Ra measurement. The projection density distribution is calculated from the obtained data, and the number of projections with a projection height of 5 nm or more is HD5, and the number of projections with a projection height of 10 nm or more is HD10.
[0055]
(5) Film thickness measurement (Tsi (nm))
The thickness of the release layer is measured by cleaving the cross section of the release film with a microtome and observing the obtained sample with a TEM.
[0056]
(6) Measurement of Silicone Containing Silicone content is determined by measuring the release film surface with ESCA and confirming the presence or absence of Si peak. However, when silicon oxide is contained in the polyester film, elemental analysis from the cross section is performed to determine the presence or absence of the Si peak.
[0057]
(7) Handling property blocking:
The release film is rolled up into 1000 rolls, and after aging at 60 ° C. for 1 month, the sticking phenomenon is visually confirmed on the release surface of the film and its back surface.
○: No blocking ×: Breakfast Russia Kkingu there slip properties:
A release film is passed through the processing machine, and a visual check is performed to check whether wrinkles are generated on the release film on the roll surface (conditions: tension 7 kg / m width, speed 50 m / min).
○: Without wrinkles ×: With wrinkles
The film surface is worn with black drawing paper, and white powder is visually confirmed.
○: No white powder ×: White powder exists [0058]
[Example 1]
First, dimethyl terephthalate and ethylene glycol were polymerized by a conventional method using manganese acetate as a transesterification catalyst, antimony trioxide as a polymerization catalyst, phosphorous acid as a stabilizer, and intrinsic viscosity (orthochlorophenol, 35 C.) 0.62 polyethylene terephthalate A was obtained.
[0059]
Polyethylene terephthalate A pellets are fed to an extruder hopper after drying at 170 ° C. for 3 hours, melted at a melting temperature of 280 to 300 ° C., and rotated with an extrusion die at a surface finish of about 0.3 s and a surface temperature of 20 ° C. The film was extruded onto a cooling drum to obtain an unstretched film having a thickness of 540 μm.
[0060]
The unstretched laminated film thus obtained is preheated to 75 ° C., and further heated by a single IR heater with a surface temperature of 900 ° C. from above 15 mm between low-speed and high-speed rolls and stretched 3.6 times. Then, it was rapidly cooled, then supplied to a stenter, and stretched 3.9 times in the transverse direction at 105 ° C. The obtained biaxially oriented film was heat-fixed at a temperature of 205 ° C. for 5 seconds to obtain a heat-fixed biaxially oriented laminated polyester film having a thickness of 38 μm. In addition, after uniaxial stretching, the water-soluble polyester resin liquid was apply | coated by the kiss coat method as an anchor process of a release layer.
[0061]
On this film, a resin having a main skeleton of amino alkyd resin having a C18 alkyl group as a side chain and further silicon oxide particles (R972, manufactured by Nippon Aerosil Co., Ltd., having an average particle size of 30 nm) as inorganic particles are 0.5 wt% per resin component. Addition. A solution having a total solid content concentration of 1% was prepared, and a release film coated with a dry film thickness of 45 nm was obtained by a conventional roll coating method. Heat drying was performed at 150 ° C. for 30 seconds. Table 1 shows the characteristics of this release film.
[0062]
[Example 2]
Dimethyl terephthalate and ethylene glycol, manganese acetate as the transesterification catalyst, antimony trioxide as the polymerization catalyst, phosphorous acid as the stabilizer, and silicon oxide with an average particle size of 0.1 μm as the inert particles of the lubricant 0.12 wt% was blended and polymerized by a conventional method to obtain polyethylene terephthalate B having an intrinsic viscosity (orthochlorophenol, 35 ° C.) of 0.62.
[0063]
In addition, after uniaxial stretching, the water-soluble polyester resin liquid was apply | coated by the kiss coat method as an anchor process of a release layer.
[0064]
On this film, a resin having a main skeleton of amino alkyd resin having a C18 alkyl group as a side chain and further silicon oxide particles (R972, manufactured by Nippon Aerosil Co., Ltd., having an average particle size of 30 nm) as inorganic particles are 0.2 wt% per resin component. Addition. A solution having a total solid content concentration of 1% was prepared, and a release film coated with a dry film thickness of 45 nm was obtained by a conventional roll coating method. Heat drying was performed at 150 ° C. for 20 seconds. Table 1 shows the characteristics of this release film.
[0065]
[Comparative Example 1]
A release film was obtained in the same manner as in Example 1 except that the inorganic particles in the release layer of Example 1 were not used.
[0066]
[Comparative Example 2]
A release film was obtained in the same manner as in Example 1 except that the thickness of the release layer in Example 1 was 1000 nm.
[0067]
[Comparative Example 3]
A release film was obtained in the same manner as in Example 1 except that the amount of particles added to the release layer in Example 1 was 30%.
[0068]
[Comparative Example 4]
A release film was obtained in the same manner as in Example 1 except that the release layer of Example 1 was mainly composed of polydimethylsiloxane.
[0069]
[Table 1]

[0070]
【The invention's effect】
According to the present invention, which has excellent surface properties large projections of releasing the film surface is not transferred to the molded sheet, excellent processability aptitude can provide no release film of silicone transfer.

Claims (3)

On the surface of the port re ester film, a releasing film having a parting layer is 300nm or less thick containing fine inert particles, the center line surface roughness Ra of the release layer is 5nm or less, ten point average roughness The thickness Rz is 30 nm or less, and the release layer is composed of a compound containing a long-chain alkyl group and not containing polydimethylsiloxane, and the thickness (t [nm]) of the release layer and the average particle diameter of the inert particles (D [nm]) satisfies the following formula ,
0.3d ≦ t ≦ 2.5d
A release film in which the relationship between the number of protrusions on the surface of the release film and the protrusion height satisfies the following formula.
HD5 (number of protrusions of 5 nm or more) ≧ 500 pieces / mm ²
HD10 (number of protrusions with a height of 10 nm or more) ≦ 100 / mm ²   The release film according to claim 1, wherein the long-chain alkyl group of the release layer has 12 to 28 carbon atoms.   The release film according to claim 1, wherein the fine inert particles in the release layer are inorganic particles having an average particle diameter of 5 to 80 nm.