JPH079626A - Release film - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a colored release film of an antistatic agent, which has stable peeling force, has hiding power and transparency, and is not mistaken for other materials. [Structure] A cured silicone resin coating film containing an antistatic agent consisting of a cationic anhydride is provided on at least one side of a plastic film dyed by an anhydrous dyeing method, and the surface specific resistance value on the coating film is 5 × 10 5. ^{3 ~5} × 10 ^{13 Ω} /
□ is a release film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a release film, more specifically, a dyed plastic film provided with a cured silicone resin coating film containing a specific antistatic agent on at least one surface thereof, and is used in combination with other materials. The present invention relates to an antistatic release film that is easy to identify and cannot be mistaken.

[0002]

2. Description of the Related Art In recent years, in accordance with a wide range of applications of adhesives, adhesives, etc., the use of silicone-coated release paper or release film for protecting the adhesive surface has been remarkably expanding in various fields. A composition containing a curable silicone resin as a main component is mainly used for the silicone coating, and as the composition, a composition which is cured by a condensation reaction (JP-A-47-34447, etc.) and a composition which is cured by an addition reaction (special characteristics: Kosho 52-40918) is known.

However, the conventional release film is difficult to distinguish from the plastic film of the same kind, and since it is a film having good see-through property, it is difficult to confirm its loading, mounting, forgetting to peel it, and remaining unpeeled film. Therefore, for example, when the composite material itself used for coloring such as liquid crystal related materials such as polarizing plates, exterior boards for multilayer printed circuit boards, thermosetting resin prepregs that require high temperature molding is colored, or product differentiation is required. In various required fields, problems such as mistakes in peeling occur. Especially when the same type of plastic film such as polyethylene film or polyester film is attached as a protective film on the opposite side such as a polarizing plate or a retardation film, the protective film may be mistaken for the release film in the processing work. Occurs with a high frequency, and is one of the fatal problems related to the decrease in yield. For materials such as print boards and prepregs, it is very important to check whether or not the release film is loaded, and if the release film is damaged during processing, it is not attached to the molded material. It is an item.

Therefore, it is desired to color the release film,
It is also being considered. For this coloring, it is necessary to satisfy both contradictory properties such as hiding power (coloring degree) and transparency. The transparency is related to the above-mentioned thing, that the material underneath can be recognized through the release film, for example, what kind of material the material is, or reading a character mark etc. written on the composite material. It is necessary to do it.

As a method for coloring a release film, a pigment or dye is directly added to a curable silicone resin composition which is a release agent, or coloring by a pigment dyeing filler has been attempted, but both are cured. Since it acts as a catalyst poison of the hydrophilic silicone resin, the reactivity is rapidly lowered, the curing is insufficient, the peeling force itself is increased, and the level of use has not been reached. On the other hand, as a method of coloring the plastic film itself as the base material, a method of mixing dyes and pigments with a polyester resin to form a film, a method of coating ink or dyes and pigments with a binder resin after film formation, and performing heat treatment, etc. However, the former method is not suitable for large-lot, small-quantity production, it also contaminates extruders, film-forming equipment, heat treatment equipment, etc., it is difficult to obtain vivid colors, and dyeing that can withstand high temperatures. There are restrictions on pigments,
It has drawbacks such as difficulty in adjusting the color density. Also,
The latter has drawbacks such as lack of surface smoothness, lack of uniformity of dyeing, difficulty of peeling of binder resin, loss of transparency, and poor fastness.

Further, there is an increasing demand for antistatic film release films. Currently, the most effective measure to eliminate static electricity trouble is static elimination, and static elimination equipment is installed at various places in the release film manufacturing process and adhesive processing process, but it is sufficient to obtain sufficient results. Absent.

A method for providing a curable silicone layer on an antistatic layer as an antistatic coating for a release film (Japanese Patent Publication No.
No. 106645), and a method of providing an ultraviolet-curable silicone coating on a plastic film internally added with an antistatic agent (Japanese Patent Publication No. 4-59207), antistatic silicone release films have been developed. However, this method has various problems in terms of cost and quality of the release film, and development of a single-layer type antistatic silicone on a general-purpose plastic film is required. However, in this development, when an antistatic agent containing, for example, nitrogen, sulfur, or phosphorus was mixed with a silicone agent, curing inhibition was found to cause them to act as catalyst poisons, and this technology was uneasy.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and to provide a strong and clear dyed plastic film as a base, which has a stable peeling force and is excellent in hiding power and transparency. Another object of the present invention is to provide a colored antistatic release film.

[0009]

The object of the present invention is to:
According to the present invention, a cured silicone resin coating film containing an antistatic agent consisting of a cationic anhydride is provided on at least one surface of a plastic film dyed by an anhydrous dyeing method, and the surface specific resistance value on the coating film is 5 x 10 ^{3 to} 5 x 10
Achieved with a release film that is ¹³ Ω / □.

In the present invention, examples of the plastic film include polystyrene, polymethyl acrylate, polycarbonate, polysulfone, triacetyl cellulose, cellophane, polyamide, polyimide, polyphenylene sulfide, polyetherimide, polyethersulfone, aromatic polyamide, polyolefin, A transparent film (containing sheet) made of polyester or the like can be preferably mentioned. Of these, polyester biaxially stretched film is preferable.

The polyester film is a lubricant which is added and contained by the film-forming step, such as clay, kaolin, silica,
The transparency can be easily controlled by adjusting the particle size and amount of calcium carbonate and the like. Also, when the surface is coated, it has excellent solvent resistance, heat resistance, and mechanical properties. Especially, in order to cure the coating film of curable silicone, the drying temperature after coating is 100
The temperature is set to ˜140 ° C., and there is an advantage that a dimensional change is small when the film is passed in this atmosphere.

Polyester is a general term for polymers having an ester bond as the main chain of the main chain, and particularly preferred polyesters are polyethylene terephthalate, polyethylene-2,6-naphthalate, polyethylene-α, β-bis (2- Chlorphenoxy) ethane-4,4'-dicarboxylate, polybutylene terephthalate and the like. Among these, polyethylene terephthalate is most preferable in view of quality, economy and the like.

The thickness of the plastic is not particularly limited, but, for example, from the waist strength required for the release film,
It is preferable to select an appropriate thickness from the range of about 1 to 500 μm.

The surface roughness and haze of the plastic film are also not particularly limited, but the thickness of the coating film described below, the adhesive strength required between the coating film and the plastic film, and the release film are required. The desired value may be set appropriately in consideration of the transparency.

In the present invention, such a plastic film is used after being dyed, and this dyeing is carried out by an anhydrous dyeing method. This anhydrous dyeing method can also be called a solvent dyeing method, and is a method of dyeing a film at a high temperature with a dye dissolved, suspended or dispersed in an organic solvent having a relatively high boiling point.

The organic solvent is preferably a hydrophilic organic solvent such as glycols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, alkyl ethers thereof, phenyl ethers, and the like. Mention may be made of polyhydric alcohols such as glycerin.

Disperse dyes are preferably used as dyes, but vat dyes and complex dyes can also be used. For example, benzoanone type, heterocyclic azo type,
Examples thereof include anthraquinone type dyes and condensation type dyes.

The density of the dye, of course, varies depending on the color density, but it varies depending on the dyeing density and the dyeing time, and is usually 3 to 15 g / l. The temperature during dyeing is usually 100
-200 degreeC, Preferably it is 120-180 degreeC. The dyeing time is usually several seconds to several minutes, preferably several seconds to several tens seconds. However, depending on the staining density, a longer time can be taken.

Dyeing is preferably carried out by passing the film through a dyeing bath at a high temperature. At that time, it is preferable to keep the dye concentration in the dye bath constant, and therefore it is preferable to constantly circulate the dye bath or replenish the fresh liquid to automatically control the dye concentration. The film discharged from the dye bath is treated with a dye bath or solvent adhering to the surface of the film, a chlorinated hydrocarbon solvent having a relatively low boiling point such as CH ₂ Cl ₂ ,
Wash with CCl ₄ , CHCl _3, etc., or with hot or hot water. When recovering and separating each component from the washing liquid, it is preferable to wash with a chlorinated hydrocarbon solvent which is easy to treat.

The degree of dyeing of the plastic film depends on the usage of the release film, but the total light transmittance is 20 to 8.
It is preferably 0%, and more preferably 25 to 70%.

In the present invention, the cured silicone resin coating film is a layer which imparts antistatic release characteristics to the plastic film, and the layer contains at least a coating liquid containing an antistatic agent and a curable silicone resin in the plastic film. It is formed by coating on one side, drying and curing.

As the curable silicone resin, any reaction system such as condensation reaction system, addition reaction system, ultraviolet ray or electron beam curing system can be used. One or more of these may be used.

The curing reaction of various silicones can be shown as follows.

[0024]

[Chemical 1]

As the condensation reaction type silicone resin, for example, polydimethylsiloxane having a terminal --OH group and polydimethylsiloxane having a --H group at a terminal (hydrogensilane) may be used as an organic tin catalyst (for example, an organic tin acylate catalyst). ) Is used to cause a condensation reaction to form a three-dimensional crosslinked structure.

As the addition reaction type silicone resin, for example, polydimethylsiloxane having a vinyl group introduced at the terminal and hydrogenenesilane are reacted using a platinum catalyst,
Examples include those that form a three-dimensional crosslinked structure.

As the ultraviolet curing silicone resin,
For example, as the most basic type, one that uses the same radical reaction as ordinary silicone rubber cross-linking, one that introduces an acrylic group for photo-curing, one that decomposes an onium salt with ultraviolet light to generate a strong acid, and then an epoxy group Examples thereof include those that are cleaved and crosslinked, and those that are crosslinked by the addition reaction of thiol to vinylsiloxane. Electron beams have higher energy than ultraviolet rays, and a crosslinking reaction by radicals occurs without using an initiator as in the case of ultraviolet curing. The curable silicone resin has a degree of polymerization of 50 to 200.
Those of about 000 are preferable, and specific examples thereof are KS-718, -774,-manufactured by Shin-Etsu Silicone Co., Ltd.
775, -778, -779H, -830, -835
-837, -838, -839, -841, -843,
-847, -847H, X-62-2418, -242
2, -2,215, -2492, -2494, -470,
-2366, -630, X-92-140, -128,
KS-723A ・ B, -705F, -708A, -88
3, -709, -719, T manufactured by Toshiba Silicone Co., Ltd.
PR-6701, -6702, -6703, -370
4, -6705, -6722, -6721, -670
0, XSR-7029, YSR-3022, YR-32
86, Dow Corning DK-Q3-202,
-203, -204, -210, -240, -300
3, -205, -3057, SFXF-2560, SD-7226, 7320, 72 manufactured by Toray Silicone Co., Ltd.
29, BY24-900, 171, 312, 374, S
RX-375, SYL-OFF23, SRX-244,
Examples thereof include SEX-290 and SILCOLASE 425 manufactured by IC Japan Co., Ltd. In addition, JP-A-47-34447 and JP-B-52
Silicone resins described in JP-A-40918 can also be used.

The antistatic agent in the present invention is an antistatic agent composed of a cationic anhydride.

[0029]

[Chemical 2]

(However, R is C₁~ C₁₈Is an alkyl group of
Alkyldimethylethylammonium having the structure
Muethyl sulphate compounds may be mentioned. Up
As R (alkyl group) in the above structural formula, --CH₃, -C
₂H_Five, -C₃H₇, -C_FourH ₉, -C_FiveH₁₁, -C₆
H₁₃, -C₇H₁₅, -C₈H₁₇, -C₉H₁₉, -C_TenH
_{twenty one}, -C₁₁H_{twenty three}, -C₁₂H_{twenty five}, -C₁₃H₂₇, -C
₁₄H₂₉, -C₁₅H₃₁, -C₁₆H ₃₃, -C₁₇H₃₅, -C₁₈
H₃₇Etc. can be illustrated.

As the alkyldimethylethylammoniumethylsulfate compound, those having R = C _{8 to} C ₁₄ are particularly preferable, and one or more of them can be used.

These are preferably added in a solid content ratio of 2 to 9 mol% with respect to the curable silicone resin. Two
If it is less than 9 mol%, the antistatic effect is poor, while if it is more than 9 mol%, the curing reaction of the silicone is inhibited, the cohesive force of the silicone thin film is weakened, and the adhesion of the coating film becomes poor. The point of mixing with the curable silicone resin is the compatibility of the antistatic agent, which is incompatible with solvent type, water, emulsion type, metal type powder, etc. Or, it causes reaction inhibition and causes a problem in the curability of silicone.

In the present invention, when a cured antistatic silicone resin coating film is provided, as a coating method, there are conventionally known methods such as a bar coating method, a doctor blade method, a reverse roll coating method and a gravure roll coating method. Is available.

The coating film can be dried and cured (heat curing, ultraviolet curing, etc.) individually or simultaneously. At the same time, it is preferably performed at 100 ° C. or higher, although it depends on the heat resistance (thermal dimensional stability) of the plastic film. The dry heat curing condition is preferably 100 ° C. or higher and about 30 seconds. When the drying temperature is 100 ° C. or lower and the curing time is 30 seconds or shorter, the coating film is not completely cured, and the durability of the coating film remains uneasy.

The thickness of the cured silicone resin coating film is not particularly limited, but is preferably in the range of 0.05 to 0.5 μm. If it becomes too thin, the release performance will deteriorate and satisfactory performance will not be obtained. If it is too thick, it takes a long time to cure, which causes inconvenience in production.

The release film of the present invention comprises a liquid crystal-related material such as a polarizing plate, a multilayer printed circuit board exterior plate,
For areas such as thermosetting resin prepregs that require high-temperature molding, where the composite material used there is colored, product differentiation, or where adhesion of dust during peeling or product yield is particularly required, and other release films. It can be applied to a wide range of fields such as various fields that require antistatic treatment and general-purpose adhesive fields including adhesive tapes. Specifically, for example, a polarizing plate, protection of an adhesive surface of a liquid crystal material such as a retardation plate, a molded sheet such as a ceramics green sheet, an adhesive tape, a label separator, various resin molded sheets such as urethane, and rubber. It can be applied to molded sheets.

The release film of the present invention has the following features. (1) Due to the low surface energy of the cured silicone film, it has good releasability without adhering to various other substances. (2) By using dyed plastic film,
Products can be differentiated and the reduction in yield due to mistakes in peeling can be reduced. (3) Due to the effect of the mixed antistatic agent having good compatibility, the surface specific resistance value of the surface of the cured silicone resin film is 5 × 10 ⁸ to
It can be reduced to 5 × 10 ¹³ Ω / □, and it is possible to avoid adhesion of dust, dust, and the like due to charging failure.

[0038]

EXAMPLES The present invention will be described in more detail with reference to examples. The various properties of the film were measured by the following methods.

(1) Surface specific resistance A film provided with a cured silicone resin coating film was prepared at 23 ° C. × 5.
After standing for 24 hours at 0 to 60% RH, measurement was performed with a vibration capacitance type potentiometer TR-84M type (manufactured by Takeda Riken).

(2) Total light transmittance of film The total light transmittance is expressed as a percentage of the ratio of the incident light quantity to the total light quantity transmitted through the sample film, and the measurement is based on JIS-
Based on the method shown in K7105-1981.
As a measuring machine, Nippon Precision Engineering Co., Ltd. POIC HA
ZEMETERSEP-HS-D1 is used.

(3) Releasability: Initial peeling force Sample film and polyester adhesive tape (knit-
31B) are stuck together and pressure bonded with a 5 kg pressure roller,
The peel strength after standing for 20 hours is measured by a tensile tester.

(4) Residual Adhesion Rate A polyester adhesive tape (knit-31B) was specified in JIS.
Cold rolled stainless steel plate (SUS3 specified in G4305
The peeling force after sticking to (04) was measured, and the basic adhesive force (f
₀ ). Further, the polyester adhesive tape is pressure-bonded to the cured silicone resin coating film surface of the sample film with a pressure roller of 5 kg, left for 30 seconds, and then the adhesive tape is peeled off. Then, the peeled pressure-sensitive adhesive tape is attached to the above-mentioned stainless steel plate, and the peeling force of the bonded portion is measured to obtain the residual adhesive force (f). For each of these adhesive strengths, the residual adhesion rate is calculated from the following equation.

[0043]

[Equation 1]

[0044]

Examples 1 to 3 Polyester film (thickness: 38 μm) dyed by the anhydrous dyeing method, which has a total light transmittance of 27.5%.
And a coating amount of 8 g / m ² (we
t) and then a drying temperature of 110
C., curing time at 30 seconds
A 4 μm release film was made. The characteristics of this release film are shown in Table 3.

<Composition of coating liquid> Curable silicone resin (KS847H) 100 parts by weight Curing agent (CAT PL-50T; manufactured by Shin-Etsu Silicone Co., Ltd.) 2 parts by weight Lauryl Dimethylethylammonium Ethyl Sulfate (Table 1) Methyl ethyl ketone / methyl isobutyl ketone / xylene 898 parts by weight

However, the addition amount of lauryldimethylethylammonium ethylsulfate in the coating solution is as shown in Table 1.

[0047]

[Table 1]

[0048]

Comparative Examples 1 to 3 A release film was prepared in the same manner as in Example 1 except that the coating solution having the following composition was used instead of the coating solution in Example 1. The characteristics of this release film are as shown in Table 3, but not only the curability is poor,
Satisfactory surface resistivity values have not been obtained. Further, if the addition amount is excessive, heavy peeling becomes remarkable, and the use level is not reached.

<Composition of coating liquid> Curing silicone resin (KS847H) 100 parts by weight Curing agent (CAT PL-50T; manufactured by Shin-Etsu Silicon Co., Ltd.) 2 parts by weight Colcoat P (manufactured by Colcoat) (Table 2) Methyl ethyl ketone / Methyl isobutyl ketone / xylene 898 parts by weight However, the addition amount of Colcoat P in the coating liquid is as shown in Table 2.

[0050]

[Table 2]

[0051]

[Table 3]

As is clear from Table 3, the films of Examples are films having both excellent releasing performance and antistatic performance.

[0053]

According to the present invention, it is possible to provide an antistatic release film which has a stable peeling force, is excellent in hiding power and transparency, and is not mistaken for other materials. .

Claims (1)

[Claims] 1. A cured silicone resin coating film containing an antistatic agent consisting of a cationic anhydride is provided on at least one side of a plastic film dyed by an anhydrous dyeing method, and the surface specific resistance value on the coating film is 5. × 10 ^{3 to} 5 × 10
Release film with ¹³ Ω / □.