JP2001239618A - Release film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a release film which can inhibit troubles of applying and releasing of coating, has appropriate wetting characteristics and peel force, and which is useful for a protective film for an adhesive coat, and for manufacturing, with high precision, a self-adhesive sheet, a resin sheet, a resin coat, or a ceramic sheet. SOLUTION: The release film is composed by partially laminating a beltlike pigmented layer having 0.0001-2 μm thickness on at least one side of a plastic film. And a release layer is laminated on a part of the surface without the pigmented layer, or on the entire surface including the release layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a release film, and more particularly, to a protective film for a pressure-sensitive adhesive film.
Alternatively, the present invention relates to a release film useful as a carrier film for molding such as an adhesive sheet, a resin sheet, a resin film, or a ceramic sheet.

[0002]

2. Description of the Related Art A release film is used as a protective film for an adhesive film. For example, the pressure-sensitive adhesive film is usually manufactured by applying a coating liquid containing a pressure-sensitive adhesive and a solvent to the surface of a base film, and then heating and removing the solvent, which protects the pressure-sensitive adhesive film. Therefore, a release film is usually laminated on the surface of the film. The release film may serve as a temporary support.

[0003] Release films have also been used as carrier films for forming pressure-sensitive adhesive sheets, resin sheets, resin films or ceramic sheets. For example, as a resin sheet, a resin solution obtained by dissolving a resin such as a vinyl chloride resin in a solvent is used as a release film (carrier film).
It is manufactured by a method of coating (casting) on the top, removing the solvent by heating, and then separating and separating from the carrier film, and is used for various uses such as a sheet for a marking sheet. Further, the resin film is formed by applying a coating liquid comprising a resin such as an adhesive and a solvent to the surface of the carrier film and then heating to remove the solvent. Furthermore, the ceramic sheet is formed, for example, by coating a slurry in which ceramic powder and a binder or the like are dispersed in a solvent on a release film (carrier film), and then removing the solvent by heating to obtain a ceramic green sheet (ceramic green). Sheet).

A release film used for such an application is often coated with a resin solution, an adhesive or a ceramic slurry over the entire width or a part of the release layer surface. As a component constituting the release layer of the release film, generally, a silicone-based resin, a fluorine-based resin, an aliphatic wax or the like is used. It is excellent in terms of stable, uniform and light peeling properties and cost when peeling off the film or sheet provided on the substrate. However, while the release layer using a silicone resin has the advantage that a light peeling force can be obtained, if the peeling force is too light due to low surface energy, depending on the type of the resin solution or ceramic slurry, the coating liquid may not be applied. In some cases, it may be repelled during coating, or even if it can be applied successfully, it may be unnecessarily peeled off when peeling, making it difficult to control the peeling. In addition, if the weight is increased in consideration of wettability and light peelability, the coating film may partially remain on the release film and may not be peeled off.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the drawbacks of the prior art and to produce a pressure-sensitive adhesive film as a protective film or a pressure-sensitive adhesive sheet, a resin sheet, a resin film or a ceramic sheet with high precision. It is an object of the present invention to provide a release film that is useful for performing

[0006]

According to the present invention, there is provided a plastic film having a band-shaped colored layer having a thickness of 0.001 to 2 μm laminated on at least a part of one surface of the plastic film. This is achieved by a release film characterized in that a release layer is laminated on a portion where no colored layer is present or on the entire surface including the colored layer.

The present invention further provides, as a preferred embodiment,
The coloring layer is a printing layer, a metal layer, or a metal compound layer, the coloring layer is a printing layer, and the release force F1 of the release layer in a portion where the printing layer does not exist to the adhesive tape is 100 m.
Greater than N / cm and less than or equal to 1000 mN / cm, the peeling force F1 of the part of the release layer where no print layer is present on the adhesive tape and the peeling force of the part of the release layer above the print layer on the adhesive tape The ratio (F2 / F1) to F2 is 1.1 or more and 60 or less, the printing layer contains a pigment or dye, the thickness of the printing layer is 0.01 to 2 μm, and the coloring layer is a metal layer or The metal layer is a metal compound layer, and the release force F1 of the metal layer or the part where the metal compound layer does not exist to the adhesive tape is 1 mN / cm or more and 100 mN / cm or more.
0 mN / cm or less, the peeling force F1 of the part of the release layer on the pressure-sensitive adhesive tape where the metal layer or the metal compound layer does not exist, and the release force F1 of the part existing on the metal layer or the metal compound layer on the adhesive tape. The ratio (F2 / F1) to the peeling force F2 is 1.1 or more and 400 or less, the coloring layer is provided in parallel with the longitudinal direction of the film, and the coloring layer is provided only on both side edges of the release film. And that the release layer is made of a curable silicone resin, and that the maximum surface tension (γLmax) of this surface determined by the following formula (1) is 30 to 100 dyne / cm. .

[0008]

ΓLmax = 1 / b + γc / 2 (1) (where b is a constant determined from the slope of the Zisman plot, and γc is the critical surface tension (dyne / cm))

[Plastic Film] As the plastic film in the present invention, a polyester film which is excellent in heat-resistant dimensional stability, flatness, fish eye and the like of the film is preferable.

When the release film is required to have transparency, the polyester film is preferably a polyester film having good transparency, and more preferably a biaxially stretched polyester film. Further, when the release film is required to have concealing properties, light-shielding properties, etc., a polyester film containing a pigment is preferable, and furthermore, an inorganic pigment such as TiO ₂ , a biaxially stretched polyester film containing SiO ₂ or the like is preferable. .

The polyester constituting such a polyester film is preferably a crystalline linear saturated polyester comprising an aromatic dibasic acid component and a diol component, and specific examples thereof include polyethylene terephthalate, polypropylene terephthalate, and polybutylene terephthalate. And polyethylene-2,6-naphthalenedicarboxylate. Some of them (usually 15 mol% or less, preferably 10
(% By mole or less) or a mixture of a small amount (usually 20% by weight or less, preferably 10% by weight or less, based on the total weight) of a polyalkylene glycol or another resin. May be.

The polyesters are known per se,
This intrinsic viscosity (orthochlorophenol, 35 ° C.) is preferably 0.4 or more, more preferably 0.45 to 0.9.

The polyester film is preferably a biaxially stretched film. The biaxially stretched film can be produced by a known method. For example, after drying the polyester, Tm to (Tm + 70) ° C. (however, Tm:
(Melting point of polyester), and extruded from a die (for example, T-die, I-die, etc.) onto a rotary cooling drum.
C. to 90.degree. C. to obtain an unstretched film, and then the unstretched film is cooled to (Tg-10) to (Tg + 70) .degree.
g: glass transition temperature of polyester) at a temperature in the range of 2 to 7 times in the machine direction, then in the range of 2 to 7 times in the transverse direction, and then heat at 160 to 260 ° C. for 1 to 60 seconds. It can be manufactured by fixing. The thickness of the film is not particularly limited, but is preferably 5 to 200 μm.

The plastic film according to the present invention comprises:
In order to improve the slipperiness and workability of the film, the center line average roughness (Ra) of the surface is preferably 2 nm or more and 500 nm or less. In order to make this surface roughness,
It is preferable that a lubricant such as inorganic fine particles and organic fine particles be contained in the film. More specifically, the average particle size is 0.01 nm or more and 20 μm or less, preferably 0.1
It is preferable to contain 0.001 to 10% by weight (based on the weight of the film) of inorganic fine particles or organic fine particles of not less than nm and not more than 5 μm. If the Ra of the film surface is less than 2 nm, the film will adhere to each other when the film is wound, and a problem that the film will not slip easily will occur. On the other hand, if the Ra is more than 500 nm, the resin sheet or the ceramic sheet coated on the release film will have a problem. It is not preferable because there is a concern that irregularities may be deformed on the surface.

Specific examples of the fine particles include silicon dioxide, aluminum oxide, kaolin, calcium carbonate, titanium oxide, aluminum silicate (including calcined products and hydrates), monolithium phosphate, trilithium phosphate, and calcium phosphate. , Lithium benzoate, barium sulfate, double salts of these compounds (including hydrates), carbon black, glass powder, clay (including kaolin, benite, clay, etc.)
And inorganic fine particles such as crosslinked acrylic resin, crosslinked polystyrene resin, melamine resin, crosslinked silicone resin, and polyamideimide resin. These fine particles may be of one kind,
There may be more than one type. In order to maintain the effects of the present invention, it is preferable to use inert particles in order to prevent a change in performance due to interaction.

When the release film is required to have a hiding property, a light-shielding property and the like, a polyester film containing a pigment is preferred. For example, it can be obtained by using the following particles of the pigment or the like. It is preferable that a lubricant having a large particle size be contained as a pigment, for example, silicon oxide, titanium oxide, calcium carbonate, glass beads, silicone resin particles, crosslinked polystyrene particles, and the like. Further, these pigments preferably have an average particle size of 1 to 20 μm, and preferably contain 0.1 to 5.0% by weight based on the weight of the polyester.

In addition to the fine particles, a stabilizer, an ultraviolet absorber, a coloring agent, a flame retardant, an antistatic agent, a light stabilizer, an antioxidant, etc. may be used as long as the surface flatness and thermal stability of the film are not impaired. Can be incorporated into the polymer. Further, other thermoplastic resin may be added in a small amount (usually 20% by weight or less, particularly 10% by weight or less).

The plastic film may be a single-layer film or a laminated film. In the case of a laminated film, the fine particles may be contained only in the surface layer, or may be contained only in the substrate film layer (or the core layer of the laminated film of three or more layers). It may be contained in a layer. Which method to use depends on the properties that the plastic film should have, such as transparency, depending on the application.
It is better to select from surface characteristics and the like.

The method for producing the laminated film includes a coating method,
A co-extrusion method is preferred. As a coating method, a method of applying and drying a coating liquid for forming a surface layer on at least one surface of the base film at the time of film formation is preferable, and as a co-extrusion method, a plurality of extruders and a feed block or a multi-manifold die are used. A co-extrusion method is preferably mentioned. In the case of the coating method, it is preferable to use a method of thinly laminating a layer containing fine particles on at least one surface of the base film.

[Coloring Layer] In the present invention, examples of the coloring layer laminated on at least one side of the plastic film, that is, one side or both sides include a printing layer, a metal layer, and a metal compound layer. The thickness of this colored layer is 0.001μ
m or more and 2 μm or less (1 nm or more and 2000 nm or less). If the thickness is less than 1 nm, a uniform film cannot be obtained, while if it exceeds 2000 nm, it is not preferable in terms of productivity.

The printing layer is formed by using an ink that can be stacked on a plastic film, and by using a conventionally known printing technique, for example, a printing method such as gravure, gravure offset, silk screen, or flexo.

The composition of the ink is not particularly limited, but usually comprises an adhesive, an antistatic agent, various inks for printing, and a composition containing particles. For example, gravure inks mainly consist of pigments, binders and additives.

The pigments are classified into organic pigments and inorganic pigments. Examples of the organic pigments include various compounds such as nitroso pigments, nitro pigments, azo pigments and condensed polycyclic pigments. For example, metal fine particles, metal oxides, hydroxides, nitrides, sulfides, ferrocyanides,
Various compounds such as chromates, sulfates, carbonates, silicates, phosphates and the like can be mentioned.

As the binder, any resin which can be dissolved in a solvent to form a varnish can be used irrespective of a natural resin or a synthetic resin. Specifically, acrylic resin, polyester resin, alkyd resin, polyurethane resin, maleic acid resin, vinyl chloride-vinyl acetate copolymer, ethyl cellulose derivative,
Rosin derivatives can be exemplified.

Examples of the additives include various ionic surfactants and electron conductive materials for suppressing charging during printing and traveling charging during transportation in a process, and suppress foaming during ink coating. For this purpose, a silicone oil or a fluorine-based surfactant can be used, and further, a wax or the like can be used for the purpose of imparting damage resistance, slipperiness and releasability to the cured film.

The thickness of the printing layer is 0.01 μm or more and 2 μm.
m or less. The print layer is preferably thinner, but if it is less than 0.01 μm, it is difficult to make the thickness of the print layer uniform, while if it exceeds 2 μm, the print layer rises when the film is wound into a roll. In some cases, problems such as impairment of the flatness of the film or occurrence of local blocking occur.

[0027] It is preferable that the printing layer itself contains a pigment or a dye so that regions having different peeling forces can be visually identified on the same release surface.

In the present invention, when a metal layer or a metal compound layer is laminated on the surface of a plastic film, the type of the metal layer or the metal compound layer is not particularly limited, but various types of metal substances containing metals can be used. For example, A
u, Ag, Cu, Al, Ni, Cr, Si and other metals and alloys, as well as metal oxides, sulfides, Sb-doped SnO ₂ and Sn-doped In ₂ O ₃ (IT
O) and other semiconductor thin film forming substances can be used. Among these, metal Al is particularly preferable in terms of manufacturing cost. Note that two or more metals and metal compounds may be used in combination. As a method for forming such a metal layer or a metal compound layer, a vapor phase growth method is preferable, and further, a vacuum evaporation method,
Sputtering or plasma CVD is preferred. Although the thickness of such a layer is not particularly limited, it is 1 nm or more and 2000
nm or less is preferable. If the thickness is less than 1 nm, a uniform film cannot be obtained, while if it exceeds 2000 nm, it is not preferable in terms of productivity.

In the present invention, the colored layer is laminated on a part of the plastic film in the form of a band. The band may be continuous or may be discontinuous including a region where the colored layer does not exist in a predetermined pattern. But it is good. The colored layer may be solid, or may have various patterns such as dots.

The direction in which the strip-shaped colored layers are laminated is not particularly limited, but is preferably the longitudinal direction of the film.
More preferably, it is preferably parallel to the longitudinal direction of the film, and particularly preferably, the colored layers are at both ends in the width direction of the release film. This is because the coated adhesive, resin solution or ceramic slurry can be applied without repelling even if it is applied continuously on colored layers with different peeling forces. This is because they can be peeled off as needed without being inadvertently peeled off, and this enables a high yield of product sampling.

The purpose of laminating the strip-shaped colored layer on at least one side of the plastic film in the present invention, that is, on one side or both sides is to use an adhesive sheet using a release film,
An object of the present invention is to minimize a peeling problem at a place where peeling is not required as a result of an external force acting during a manufacturing process of a resin sheet, a resin film, a ceramic sheet, or the like. In addition, for sheets such as adhesives and ceramics that are difficult to peel off with the colored layer alone, by stacking a release layer on it,
An object of the present invention is to enable peeling with an appropriate peeling force. Furthermore, when applying a resin solution or ceramic slurry by coloring by printing, vapor deposition, or the like, it is possible to confirm a more accurate position using an apparatus such as an edge positioner.

The coloring layer is laminated before the release layer is laminated. The release layer is laminated on the same surface as the colored layer, on the entire surface including the colored layer, or on a portion excluding the colored layer. Thereby, on the same surface of the film,
It is possible to secure a region where the peeling force is heavy and a region where the peeling force is light. This is because if there is no release layer on the colored layer, the peel strength of the colored layer is greater than that of the release layer, and if the release layer is also laminated on the colored layer, It is considered that the release layer on the top is thinner than the release layer in the portion where the colored layer does not exist, resulting in heavy peeling. As a result, only the colored layer or the release layer on the colored layer has a modest adhesiveness (peelability), and does not peel off except in the original peeling step. In the peeling step, it is possible to peel with an appropriate peeling property.

The width of the colored layer is not particularly limited, but is preferably in the range of 0.5 mm or more and 50 mm when it is necessary to secure an effective coating width for collecting the product. When the width of the coloring layer is less than 0.5 mm, the release force of the release layer in the portion where the coloring layer does not exist is smaller than that of the coloring layer or the release layer thereon, so that the applied sheet floats or peels off. On the other hand, if it exceeds 50 mm, the ratio of the width of the colored layer to the width of the release film may become large, and the peeling force as a whole becomes too large.
May not be preferred.

Further, the ratio of the width of the colored layer to the entire width of the release film is preferably 0.1% or more and 50% or less. If this ratio is less than 0.1%, the applied sheet may float or peel off since the release force of the release layer in the portion where the colored layer does not exist is lower than that of the colored layer or the release layer thereon. On the other hand, when it exceeds 50%, the peeling force as a whole becomes too large, which may not be preferable.

[Release Layer] The release film of the present invention has a release layer on one or both sides of a plastic film. This release layer is not particularly limited as long as it is a material having a release property, but in terms of stable release properties and workability, it is made of a curable silicone resin containing polydimethylsiloxane as a main component. Is preferred. Further, the release layer has a maximum surface tension (γLmax) determined by the following equation (1).
Is preferably 30 to 100 dyne / cm.

[0036]

ΓLmax = 1 / b + γc / 2 (1) (where b is a constant determined from the slope of the Zisman plot, and γc is the critical surface tension (dyne / cm).)

In the above formula (1), b is the following Zis
is a constant determined from a man plot, and γc is a critical surface tension determined by the following method. That is, several standard solutions having a surface tension in the range of 20 to 40 dyne / cm are prepared, and these standard solutions are dropped on the release layer of the film, and the contact angle between the standard solution and the release layer (θ ) Is measured. The value of cos θ is calculated from the obtained contact angle (θ), the value of cos θ is plotted against the value of the surface tension of the standard solution (Zisman plot), and the magnitude of the slope of the straight line is defined as b. Also,
The value of the surface tension at the intersection of the straight line of the Zisman plot and the straight line indicated by cos θ = 1 is defined as γc (critical surface tension).

Here, γLmax is defined as the surface tension (dyne / cm) of the liquid which maximizes the adhesive force (W: dyne / cm) represented by the following equation (2).

[0039]

W = γS + γL−γSL (2) (where γS is the surface tension of a solid (dyne / cm 2), γL is the surface tension of a liquid (dyne / cm 2), and γSL is the surface between the solid and the liquid. The tension (dyne / cm) is shown.)

If the γLmax is less than 30 dyne / cm, repelling becomes large when a resin solution or slurry is applied, and the coating film becomes non-uniform or missing. And may come off partly. On the other hand, when γLmax exceeds 100 dyne / cm,
The adhesion between the pressure-sensitive adhesive or sheet and the release layer becomes too large,
It becomes difficult to peel them from the release film.

In the present invention, the component of the release layer (the portion where no colored layer is present) has a γLmax of 30 to 100 dyne / cm.
Although it is not particularly limited as long as it is a release layer, for example, a commercially available addition-type and / or polycondensation-type silicone for release paper having polydimethylsiloxane as a main skeleton is preferable. Examples of further improved wettability include those containing the following components, or the following modified silicones and organic resin-modified silicones.

(A) A silicone resin having the following structure of D unit, T unit and / or Q unit is blended into the polydimethylsiloxane polymer to adjust the concentration of methyl group in the release layer to increase the surface tension. What let you do. The mixing ratio of this silicone resin is 20 to 60% by weight in terms of solid content.
It is preferred that If the blending ratio is less than 20% by weight, the wettability of the release layer may be poor, while if it exceeds 60% by weight, the release layer may be too hard and the abrasion resistance may be poor. It is not preferable because there is.

[0043]

Embedded image

[0044]

Embedded image

[0045]

Embedded image In the D unit and the T unit, R represents an alkyl group such as a methyl group or an aromatic hydrocarbon group such as a phenyl group.

(B) A polydimethylsiloxane polymer mixed with a silica filler such as colloidal silica to increase the surface tension by adjusting the concentration of -Si-OH groups in the release layer to be high. .

(C) Modified polydimethylsiloxane in which a part of methyl groups in the polydimethylsiloxane polymer is substituted by a bulky phenyl group. Due to the steric hindrance of the phenyl group, for example, the rotational motion around the -Si-O-Si- bond in the polymer is suppressed, and as a result, the concentration of methyl groups on the surface of the release layer decreases, thereby increasing the surface tension. Can be. The substitution ratio of the phenyl group is not particularly specified, but is preferably 3 to 40 mol%.

(D) As the organic resin-modified silicone,
A resin having a resin composition obtained by blending a resin mixture of an alkyd resin, an acrylic resin or a melamine resin and a silicone resin as a main component is exemplified. The alkyd resin or the acrylic resin is used alone or at a certain mixing ratio, and at least a part of the alkyd resin or the acrylic resin forms a copolymer with the silicone resin.
The melamine resin mainly acts to crosslink with the acrylic resin to cure the release layer. The alkyd resin or the acrylic resin may be mixed with a silicone resin during or after its production, and the alkyd resin or the acrylic resin may be graft-copolymerized with the silicone resin.

An alkyd resin or an acrylic resin is blended to improve the wettability of the surface of the release layer, to increase the toughness of the release layer, and to obtain an appropriate release property.

The alkyd resin has a skeleton of a condensate of a polybasic acid such as phthalic anhydride as an acid component and a polyhydric alcohol such as glycerin or ethylene glycol as a glycol component. It is a resin modified with. For example, castor oil-modified alkyd resin, soybean oil-modified alkyd resin, linseed oil-modified alkyd resin, and the like are used, and alkyd resins modified with various fatty acids can be used in any combination.

Examples of the acrylic resin include polyacrylic acids such as polyacrylic acid and polymethacrylic acid, and polymethyl methacrylate and polyethyl methacrylate. Further, higher alkyl methacrylate or a part thereof is used. For example, acrylic acid esters such as those obtained by hydroxylation can be used.

As the melamine resin, for example, methylated melamine resin, butylated melamine resin, methylated urea melamine resin and the like can be used.

As a catalyst for the crosslinking reaction between the melamine resin and the alkyd resin or the acrylic resin, for example, an acidic catalyst such as sodium p-toluenesulfonate can be used.

The silicone resin is a polymer whose basic skeleton is composed of polydimethylsiloxane, and preferably has a phenyl group, an alkyl group or the like at a terminal or a side chain in order to improve compatibility with an acrylic resin or the like. Specific examples include polyphenylpolysiloxane and hydroxyl-substituted diphenylpolysiloxane. The mixing ratio of the silicone resin is preferably 1 to 30 parts by weight of the silicone resin based on 100 parts by weight of the total amount of the melamine resin and the alkyd resin or the acrylic resin.
Particularly preferred is 10 to 10 parts by weight.

The thickness of the release layer is not particularly limited.
It is preferably from 0.01 to 3 μm, particularly preferably from 0.0
It is preferably from 5 to 1 μm. This thickness is 0.01
If it is less than μm, there is a concern that the coating of the base film with the silicone resin is not sufficient, and poor peeling may occur. On the other hand, when the thickness is more than 3 μm, the absolute amount of unreacted substances and low-molecular silicone increases, which may cause migration or blocking of the silicone.

In the present invention, when a printing layer is provided as a colored layer, the release force F1 of the part of the release layer on the pressure-sensitive adhesive tape where the printing layer does not exist is 100 mN /.
cm and preferably 1000 mN / cm or less. When the release force of the release layer is 100 mN / cm or less, the release force may be repelled when the adhesive or the ceramic slurry is applied, or the release force may be too light after sheeting, and only the portion where the print layer does not exist may float. is there. On the other hand, when the release force of the release layer is larger than 1000 mN / cm, the release force of the release layer may be too high to cause problems such as inability to release.

Further, the peeling force F1 of the part of the release layer on the pressure-sensitive adhesive tape where the print layer does not exist, and the peeling force F2 of the part of the release layer on the print layer where the print layer does not exist.
Is preferably 1.1 or more and 60 or less. If the ratio of the peeling force is less than 1.1, there may be a problem that the peeling force of the part of the release layer existing on the printing layer is light and the formed sheet is easily peeled off.
On the other hand, when the ratio of the peeling force is larger than 60, the peeling force of the release layer in the portion existing on the print layer becomes too heavy, and there may be a problem such that only this portion does not peel.

The release layer in the present invention generally has a metal layer or a metal compound layer provided as a colored layer.
Since the thickness of the metal layer or the metal compound layer can be made smaller than when the printing layer is provided, the step of the adhesive solution or ceramic slurry to be applied can be reduced depending on the presence or absence of the metal layer or the metal compound layer. The thickness of these coatings can be reduced. As a result, the thickness of the obtained pressure-sensitive adhesive sheet or ceramic sheet is reduced, so that the strength of each sheet is reduced. Therefore, it is necessary to reduce the peeling force of the release film itself.
Therefore, the peeling force F1 of the part where the metal layer or the metal compound layer does not exist on the release tape of the release layer is 1 mN / cm.
It is preferably at least 1000 mN / cm. When the peeling force is less than 1 mN / cm, the adhesive may be repelled at the time of application of the adhesive or the ceramic slurry, or the peeling force after the sheet may be too light to float only in a portion where the print layer does not exist. On the other hand, when the peeling force is 1000
If it is larger than mN / cm, the release force of the release layer may be so high that problems such as inability to peel off may occur.

Further, the peeling force F of the part of the release layer where the metal layer or the metal compound layer does not exist on the adhesive tape is obtained.
The ratio (F2 / F1) of 1 to the peeling force F2 of the release layer of the part existing on the printing layer to the adhesive tape is smaller than that of the printing layer in the part where the metal layer or the metal compound layer is not present. Since the peeling force F1 of the release layer to the pressure-sensitive adhesive tape can be reduced, it is preferably 1.1 or more and 400 or less.
When the ratio of the peeling force is less than 1.1, the peeling force of the part where the release layer exists on the metal layer or the metal compound layer is light,
In some cases, problems such as the molded sheet being easily peeled off may occur. On the other hand, if the ratio of the peeling force is larger than 400, the peeling force of the part existing on the metal layer or the metal compound layer of the release layer becomes too heavy, and such a problem that only this part does not peel off occurs. There are cases.

[Method of Coating Release Layer] In the present invention,
The release layer is provided on one or both sides of the plastic film, and the release layer is formed, for example, by applying a coating liquid containing a component constituting the release layer to the film, heating and drying and curing to form a coating film. By doing so, it can be applied. As a coating method of the coating liquid, any known coating method can be applied, and examples thereof include a roll coating method, a blade coating method, and a bar coating method, but are not limited to these methods. .

In the present invention, the plastic film
To improve the adhesion between the mold and the release layer.
Providing an adhesive layer on at least one side of the
It is preferable to laminate a release layer. This adhesive layer has an example
For example, a silane coupling agent can be used. this
As the silane coupling agent, a general formula Y-Si-X _Three
Can be mentioned. Where Y is
For example, amino group, epoxy group, vinyl group, methacryl
X, a functional group represented by a mercapto group, etc.
Shows a hydrolyzable functional group represented by a silyl group. This bond
The preferred thickness of the layer is from 0.01 to 5 μm, in particular from 0.
02 to 2 μm.

[0062]

The present invention will be further described below with reference to examples. In addition, each characteristic value of the film was measured by the following method.
Parts in the examples mean parts by weight.

(1) Peeling force F1 of the part of the release layer to the adhesive tape where no colored layer is present, F2 Peeling force of the part of the release film to the adhesive tape above the colored layer Nitto 31B tape (manufactured by Nitto Denko Corporation) is affixed to the release layer surface with a rubber roller, and adhered back and forth with a 20N rubber roller once. 23 ° C, 55 ± 5% humidity
The sample is left under the condition of H for 30 minutes, and then cut into strips having a width of 25 mm. Using a tensile tester (Strograph, manufactured by Toyo Seiki Co., Ltd.), the bonded tape was removed by 300 mm.
/ Min at 180 °, and the peel force F
1 (unit: mN / cm). Similarly, the peeling force F2 is measured in the same manner as described above, except that the pressure-sensitive adhesive tape is adhered to the part of the release layer on the colored layer.

(2) Coatability and Peelability of Ceramic Green Sheet A ceramic sheet is prepared from the following components using the following materials. Various materials are mixed by a ball mill and dispersed by a Hegman grind gauge so as to be 7 or more, and then this ceramic powder dispersion slurry is dried on a release film using a straight edge applicator to a thickness of 15 μm.
After drying at 110 ° C. for 2 minutes, the repelling state and the state of peeling from the release film are observed, and evaluated according to the following criteria.・ Ceramic slurry compounded ceramic powder 100 parts Binder: polyvinyl butyral resin 25 parts Plasticizer: dibutyl phthalate 10 parts Organic solvent 65 parts ・ Observation evaluation a. Appearance of coating (coatability) ○: no repelling (good wettability) △: slight repelling observed (slightly good wetting) ×: repelling observed (poor wetting) a. Peelability ○: The ceramic sheet can be peeled with an appropriate peeling property. ：: Partial peeling of the ceramic sheet occurs. ×: Poor peeling of the ceramic sheet occurs. Is too heavy to peel off.)

(3) Maximum surface tension of release layer (γLmax) Methyl benzoate is mixed with isopropyl acetate at an appropriate ratio to prepare several standard solutions having a surface tension in the range of 20 to 40 dyne / cm. . The surface tension is measured by the Dunuy ring pulling method. Next, this standard solution is dropped on the release layer of the film, and the contact angle (θ) between the standard solution and the release layer is determined.
Is measured. The cos θ value is calculated from the obtained contact angle (θ), a plot (Zisman plot) of the cos θ value and the surface tension measured by the above method is created, and the magnitude of the slope of the straight line is defined as b. . Also, this Z
The value of the surface tension at the intersection of the straight line of the isman plot and the straight line indicated by cos θ-1 is defined as γc (critical surface tension). Using b and γc thus obtained, γLmax is obtained from the following equation (1).

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ΓLmax = 1 / b + γC / 2 (1) In the above equation (1), b is a constant determined from the slope of the Zisman plot, and γc is the critical surface tension (d
yne / cm).

(4) Thickness of printing layer The thickness of the printing layer and the thickness of the printing layer without the printing layer were measured by an electronic micrometer (manufactured by Anritsu Corporation). Thickness.

(5) Thickness of Metal Layer or Metal Compound Layer Using a stylus type surface roughness meter (Surfcoder 30C, manufactured by Kosaka Laboratory Co., Ltd.) under the conditions of a needle radius of 2 μm and a stylus pressure of 30 mg. Then, the surface of the film with and without the metal layer (or metal compound layer) is scanned, the displacement is measured, and the center line surface roughness is determined. The difference between the two positions is defined as the thickness of the metal layer (or metal compound layer).

Example 1 Polyethylene terephthalate having an intrinsic viscosity of 0.62 (orthochlorophenol, 35 ° C.) containing 0.1% by weight of spherical silica particles having an average particle diameter of 0.15 μm was melted by an extruder. The sheet was extruded from a die into a sheet, and was closely adhered to a rotating cooling drum maintained at 40 ° C. by using an electrostatic adhesion method, and rapidly cooled to obtain an unstretched film. Next, the unstretched film was stretched 3.5 times in the machine direction at 90 ° C. and then 3.6 times in the transverse direction at 95 ° C.
Further, heat fixing was performed at 220 ° C. to obtain a biaxially stretched polyethylene terephthalate film having a thickness of 38 μm.

Next, the film was slit into a width of 150 mm, and two side edges of the film were formed by gravure printing.
The yellow pigment “SYMULER FAST YELLOW 4119” is set so that the thickness becomes 0.3 μm in every 0 mm.
(Manufactured by Dainippon Ink and Chemicals, Inc.).

On the other hand, 200 parts of an acrylic resin (polymethyl methacrylate), 60 parts of a melamine resin (butylated melamine resin) and 40 parts of a silicone resin (polyphenylpolysiloxane) (100 parts of a resin mixture composed of an acrylic resin and a melamine resin) On the other hand, a resin composition obtained by mixing about 15 parts of a silicone resin) was dissolved in a mixed solvent of toluene and methyl ethyl ketone to prepare a solution having a total solid content of 2% by weight. further,
An acid catalyst (p-toluenesulfonic acid) was added to the above solution as a curing reaction accelerator to prepare a coating solution.

This coating solution was applied to the entire surface (one side) of the film on which the printed layer had been laminated, and was dried by heating at 150 ° C. for 1 minute to cure the coating film, and the release film having a release layer thickness of 0.1 μm. I got Table 1 shows the characteristics of the release film.

Example 2 A release film was obtained in the same manner as in Example 1, except that the thickness of the printing layer was changed to 1.5 μm. Table 1 shows the characteristics of the release film.

Example 3 A release film was obtained in the same manner as in Example 1, except that the thickness of the print layer was changed to 1.5 μm, and the coating liquid to be used as the release layer was changed as follows. Table 1 shows the characteristics of the release film.

A curable silicone of the addition reaction type consisting of polydimethylsiloxane having a vinyl group and dimethylhydrogensilane is dissolved in a mixed solvent of toluene and methyl ethyl ketone, and colloidal silica having an average particle diameter of 0.1 μm is cured with the curable silicone. It was blended so as to have a solid content ratio of 0.5% by weight with respect to silicone to prepare a solution having a total solid content of 2%. A platinum catalyst was added to this solution to prepare a coating solution.

[Example 4] In Example 1, instead of gravure printing, Al (metal) was vapor-deposited by a vacuum vapor deposition machine so that the thickness of the layer became 40 nm. A release film was obtained in the same manner except that the content was changed. Table 1 shows the characteristics of the release film.

A curable silicone of the addition reaction type consisting of polydimethylsiloxane having a vinyl group and dimethylhydrogensilane is dissolved in a mixed solvent of toluene and methyl ethyl ketone.
Was mixed with the above-mentioned curable silicone so as to have a solid content ratio of 0.1% by weight to prepare a solution having a total solid content of 2%. A platinum catalyst was added to this solution to prepare a coating solution.

[Comparative Example 1] A release film was obtained in the same manner as in Example 3, except that the belt-shaped printing layer was not laminated. Table 1 shows the characteristics of the release film.

Comparative Example 2 A release film was obtained in the same manner as in Example 3, except that the thickness of the print layer was changed to 3 μm. Table 1 shows the characteristics of the release film.

Comparative Example 3 A release film was obtained in the same manner as in Example 1 except that the thickness of the print layer was changed to 3 μm and the coating liquid for the release layer was changed to the following coating liquid. Table 1 shows the characteristics of the release film.

Curable silicone of the type in which a platinum catalyst is added to a mixed solution of polydimethylsiloxane and dimethylhydrogensilane to cause an addition reaction (Shin-Etsu Chemical Co., Ltd.)
(KS847 (H)) was dissolved in a mixed solvent of toluene and methyl ethyl ketone to prepare a solution having a solid concentration of 2%. A platinum catalyst was added to this solution to prepare a coating solution.

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[Table 1]

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EFFECT OF THE INVENTION The release film of the present invention minimizes the problems of coating and peeling of paint, has appropriate wettability and peeling force, and is used as a protective film for an adhesive film, and as a pressure-sensitive adhesive sheet or resin sheet. , A release film useful for producing a resin film or a ceramic sheet with high precision. It is a release film particularly useful for producing a ceramic sheet.

Continued on the front page F-term (reference) 4F100 AA01B AA01C AA20H AB01B AB01C AK01A AK01D AK01E AK25 AK36 AK42 AK52D AK52E AR00B AR00C AS00D AS00E BA03 BA05 BA06 BA10A BA10D BA10E BA20 BCA1 CCB CAB CAB E12 JB12E JK06 JK06B JK06C JL10B JL10C JL14 YY00B YY00C YY00D YY00E

Claims (11)

[Claims] 1. A strip-shaped colored layer having a thickness of 0.0001 to 2 μm is laminated on at least a part of one side of a plastic film, and a release layer is formed on a part of the plastic film where the colored layer does not exist or on the entire surface including the colored layer. A release film, characterized in that is laminated. 2. The release film according to claim 1, wherein the coloring layer is a printing layer, a metal layer, or a metal compound layer. 3. The coloring layer is a printing layer, and the release force F1 of the release layer in the portion where the printing layer does not exist to the pressure-sensitive adhesive tape is 1
The release film according to claim 1, wherein the release film is greater than 00 mN / cm and 1000 mN / cm or less. 4. The ratio (F) of the peeling force F1 of the part of the release layer to the pressure-sensitive adhesive tape of the part where the print layer does not exist and the peeling force F2 of the part of the part of the release layer above the print layer to the pressure-sensitive adhesive tape.
2 / F1) is 1.1 or more and 60 or less, The release film in any one of Claims 1-3. 5. The release film according to claim 1, wherein the printing layer contains a pigment or a dye, and the thickness of the printing layer is 0.01 to 2 μm. 6. The coloring layer is a metal layer or a metal compound layer, and the release force F1 of the release layer of the part where the metal layer or the metal compound layer does not exist to the adhesive tape is 1 mN / cm.
The release film according to claim 1, wherein the release film has a thickness of 1000 mN / cm or less. 7. A peeling force F1 of a part where the metal layer or the metal compound layer is absent from the release layer to the pressure-sensitive adhesive tape, and a peeling force of a part existing on the metal layer or the metal compound layer to the pressure-sensitive adhesive tape. Ratio with F2 (F2 / F1)
The release film according to any one of claims 1, 2 and 6, wherein the value is 1.1 or more and 400 or less. 8. The release film according to claim 1, wherein the coloring layer is provided in parallel with the longitudinal direction of the film. 9. The release film according to claim 1, wherein a colored layer is provided only on both side ends of the release film. 10. The release layer is made of a curable silicone resin, and the maximum surface tension (γLmax) of this surface determined by the following formula (1) is 30 to 100 dyne / cm.
10. The release film according to any one of claims 9 to 9. ΓLmax = 1 / b + γc / 2 (1) (where b is a constant determined from the slope of the Zisman plot, and γc is the critical surface tension (dyne / cm)) 11. The release film according to claim 1, which is used as a carrier film for producing a ceramic green sheet.