JP2020111698A - Peelable silicone resin composition and peeling film coated with the same - Google Patents

Abstract

To provide a peelable silicone resin composition which has good adhesiveness between an easy adhesion treatment film and an untreated polyester film, and a peelable silicone resin composition which prevents generation of an adhesive residue of a glass surface and a peeling film coated with the same.SOLUTION: There are provided: a peelable silicone resin composition that is composed of polyorganosiloxane (A) which is composed of a silicon atom other than a terminal bonded with a vinyl group and has a weight average molecular weight of 300,000 to 1,000,000, polyorganosiloxane (B) which has vinyl groups at both of terminals and has a weight average molecular weight of 10,000 to 100,000, polyorganohydrogen siloxane (C) having a hydrogen atom directly bonded to the silicon atom other than the terminal, a curing catalyst (D), a reactive functional group-containing hydrolyzable silane compound (E) and an aluminum chelate compound (F); and a peeling film coated with the same.SELECTED DRAWING: None

Description

The present invention relates to a releasable silicone resin composition having good adhesion to an easy-adhesion-treated film or an untreated polyester film that has not been subjected to an easy-adhesion treatment. An easy-adhesion layer or an easy-adhesion-treated untreated polyester film is applied to an untreated polyester film to form a silicone layer, the silicone layer side of the release film is adhered to glass, and when the release film is peeled together after a long time, The present invention relates to a releasable silicone resin composition in which an increase in adhesive strength over time is small and so-called adhesive residue does not occur on a glass surface, and a release film coated with the same.

Conventionally, as a fixing sheet that can be easily re-attached, can be peeled with a slight peeling force when re-peeling, and adhesive residue does not occur, in a fixing sheet in which an easy-adhesion layer and a silicone layer are laminated on at least one surface of a substrate, The adhesive layer is made of a polyester resin having a hydroxyl value of 10 to 45 or an acrylic resin having a hydroxyl value of 10 to 45, and the silicone layer is made of a linear polyorganosiloxane having vinyl groups only at both ends. , A silicone composed of a linear polyorganosiloxane having vinyl groups at both ends and side chains, a silicone composed of a branched polyorganosiloxane having vinyl groups only at the ends, and a branched chain having a vinyl group at the ends and side chains A fixing sheet has been proposed which is characterized in that at least one kind of silicone selected from silicones made of polyorganosiloxane is crosslinked with an organohydrogenpolysiloxane, and the silicone layer contains silicone oil (Patent Document 1). 1).

However, when the fixing sheet is adhered to glass, the silicone oil migrates to the interface with the glass and inhibits the reaction between the SiH group that did not contribute to the addition reaction of silicone and the OH group on the glass surface, thereby fixing the fixing sheet. Since adhesive residue is prevented when the sheet is peeled off again, unreacted organohydrogenpolysiloxane and silicone oil may remain on the glass surface when the fixed sheet is peeled off, which may contaminate the glass surface. There is a problem called.

In the fixing sheet, the polyester resin or acrylic resin forming the easy-adhesion layer has a high hydroxyl value of 10 to 45, and the polyester resin or acrylic resin having a hydroxyl value of less than 10 is: Since the adhesive force between the easily-adhesive layer and the silicone layer formed by this is weakened, there is a problem that it is difficult to use for forming the easily-adhesive layer. When the easy-adhesion layer is formed on the upper side, there is a problem that the silicone layer described in Patent Document 1 cannot be applied.

On the other hand, as a releasable silicone resin composition that solves these problems and a release film coated with the same, a base film is coated with a polyester resin having a hydroxyl value of 3 to 45 mgKOH/g on at least one surface to form an easily adhesive layer. Which is a releasable silicone resin composition to be applied to the easy-adhesion layer of the prepared easy-adhesion-treated film, which has a vinyl group at both ends and has a weight average molecular weight of 300 to 1,000,000 and is a linear or branched poly An organosiloxane (A), a linear or branched polyorganosiloxane (B) having vinyl groups at both ends and having a weight average molecular weight of 1 to 100,000, and an OH group content of less than 1% by weight. Silicone resin having a general formula of SiO _1/2 units and SiO _4/2 units, and a molar ratio of SiO _1/2 units to SiO _4/2 units of 0.5:1.0 to 0.8:1.0 (C), a polyorganohydrogensiloxane (D) having a viscosity of 10 to 100 cSt/25° C. and having a hydrogen atom directly bonded to a silicon atom in a side chain, a curing catalyst (E) necessary for an addition reaction, A releasable silicone resin composition comprising a reactive functional group-containing hydrolyzable silane compound (F) and an aluminum chelate compound (G), and a releasable product obtained by applying the releasable silicone resin composition A film has been proposed (Patent Document 2).

Japanese Patent No. 4505649 JP, 2016-98286, A

However, even though the peelable silicone resin composition described in Patent Document 2 and the peeling film coated with the same have good adhesiveness to a film having an easy-adhesion layer having a hydroxyl value of less than 10 mg, There is a problem that the adhesiveness may become insufficient with time for an untreated polyester film that has not been subjected to easy adhesion treatment, and the absolute value of the peel strength indicating the adhesiveness to glass increases with time. And a peelable silicone resin composition having sufficient peelability and tackiness for an untreated polyester film that has not been subjected to an easy adhesion treatment, and the same. There is a problem that it is difficult to say that it is a coated release film.

The problem to be solved by the present invention is a releasable silicone resin composition having good adhesion to the easy-adhesion layer even if the easy-adhesion layer formed on the easy-adhesion treated film has a hydroxyl value of less than 10. The adhesiveness does not become insufficient over time even for untreated polyester film that has not been subjected to easy adhesion treatment, and the absolute value of the peel strength indicating the adhesiveness to glass is larger over time. The release film has sufficient releasability for a long period of time because it is less likely to be formed, and further, from these, an untreated polyester film which has not been subjected to easy adhesion treatment is coated with the release silicone composition of the present invention. Even with sufficient releasability and tackiness, and in addition, no adhesive residue is produced on the glass surface, and the glass surface is not contaminated, a releasable silicone resin composition and a release film coated with the same are provided. To provide.

In order to solve the above-mentioned problems, the invention according to claim 1 provides an easy-adhesion treated film having an easy-adhesion layer formed by coating a polyester resin having a hydroxyl value of 3 to 45 mgKOH/g on at least one surface of a base film. A peelable silicone resin composition, which is applied to an easy-adhesion layer or is applied to the surface where the base film is a polyester film and the easy-adhesion layer is not formed,
A linear or branched polyorganosiloxane (A) having a vinyl group bonded to a silicon atom other than the terminal and having a weight average molecular weight of 300 to 1,000,000;
A linear or branched polyorganosiloxane (B) having vinyl groups at both ends and having a weight average molecular weight of 100,000 to 100,000;
A polyorganohydrogensiloxane (C) having a hydrogen atom directly bonded to a silicon atom other than the terminal,
A curing catalyst (D) necessary for the addition reaction,
A hydrolyzable silane compound (E) containing a reactive functional group,
An aluminum chelate compound (F),
A releasable silicone resin composition comprising:

Further, the invention according to claim 2 further has an OH group content of 0.1 to 5.0% by weight and is composed of the general formula SiO _1/2 unit and SiO _4/2 unit, wherein SiO _1/2 unit/SiO The peelable silicone resin composition according to claim 1, comprising a polyorganosiloxane (G) having a molar ratio of _4/2 units of 0.5 to 1.0.

Further, the invention according to claim 3 is characterized in that the reactive functional group-containing hydrolyzable silane compound (E) is 3-glycidoxypropyltrimethoxysilane. A peelable silicone resin composition is provided.

Further, the invention according to claim 4 is characterized in that the aluminum chelate compound (F) is aluminum trisethylacetoacetate, and the releasable silicone resin composition according to any one of claims 1 to 3. provide.

In the invention according to claim 5, the reactive functional group-containing hydrolyzable silane compound (E) is a total of polyorganosiloxane (A), polyorganosiloxane (B) and polyorganohydrogensiloxane (C). The releasable silicone resin composition according to any one of claims 1 to 4, which is 0.8 to 3.5 parts by weight based on 100 parts by weight of the compounding part.

In the invention according to claim 6, the aluminum chelate compound (F) is 100 parts by weight based on 100 parts by weight of the total amount of the polyorganosiloxane (A), the polyorganosiloxane (B) and the polyorganohydrogensiloxane (C). The peelable silicone resin composition according to any one of claims 1 to 5, characterized in that it comprises 0.08 to 0.35 parts by weight.

Further, the invention according to claim 7, the hydroxyl value is applied to at least one surface of the base film 3 to 45 mgKOH/g of a polyester resin to form an easy adhesion layer on the easy adhesion layer of the easy adhesion treatment film, Alternatively, the base film is a polyester film, and the peelable silicone resin composition according to any one of claims 1 to 6 is applied to the surface on which the easily adhesive layer is not formed to form a silicone layer. The release film is characterized by the following.

The peelable silicone resin composition of the present invention has good adhesiveness even when the easy-adhesion layer provided on at least one surface of the easy-adhesion treated film is formed of a polyester resin having a hydroxyl value of less than 10. There is an effect. In addition, it has an effect that the adhesiveness does not become insufficient with time even for an untreated polyester film which has not been subjected to easy adhesion treatment, and the absolute value of the peel strength showing the adhesiveness to glass is larger with time. It has an effect of having sufficient releasability for a long period of time because of a small degree, and in particular, a releasability obtained by applying the releasable silicone resin composition of the present invention to an untreated polyester film which has not been subjected to easy adhesion treatment due to these effects. Even a flexible film has the effect of having sufficient peelability and tackiness.

Furthermore, with the peelable silicone resin composition of the present invention, the silicone layer side of a release film obtained by forming a silicone layer on an easily-adhesive-treated film or an untreated polyester film is adhered to glass and peeled after a further long time has passed. Even if the film is peeled off from the glass, there is an effect that no adhesive residue is left on the glass surface. In addition, since the silicone oil that easily migrates is not used, there is an effect that the glass surface is not contaminated.

Particularly, in the release film according to claim 7, the easy-adhesion layer formed on the base film is formed of a polyester resin having a hydroxyl value of 10 mg/KOH or less, or the base film is a polyester film. Even if it is an untreated polyester film on which the easy-adhesion layer is not formed, the adhesiveness between the silicone layer and the base film is sufficient and there is an effect that peeling does not occur easily. , Adhesion to glass, in peeling the release film from the glass after a further long time, has sufficient adhesiveness and releasability, and also has the effect that adhesive residue does not occur on the glass surface, Further, there is an effect that the glass surface is not contaminated.

Hereinafter, the peelable silicone resin composition according to the present invention will be specifically described.

<Polyorganosiloxane (A)>
The polyorganosiloxane (A) used in the present invention is a linear or branched polyorganosiloxane having a vinyl group bonded to a silicon atom other than the terminal and having a weight average molecular weight of 300 to 1,000,000. It is used in combination with the polyorganosiloxane (B) shown in. In particular, since the polyorganosiloxane (A) has a large molecular weight, it is used to develop viscoelastic adhesiveness to the easy-adhesion layer formed on the easy-adhesion-treated film or the untreated polyester film surface. The polyorganosiloxane (A) is cured by an addition reaction with the organohydrogensiloxane (C) and the curing catalyst (D) shown below, and the organic groups other than the vinyl group which are bonded to the silicon atom may be different or the same. Specific examples thereof include a methyl group, an ethyl group, and a phenyl group. As a specific example, a vinyl group is bonded to a part of silicon atoms other than terminals of polydimethylsiloxane ((methyl bonded to silicon atoms other than terminals). Some of the groups are substituted with vinyl groups). The weight average molecular weight of the polyorganosiloxane is preferably from 300 to 1,000,000 as measured by GPC, and when it is less than 300,000, the viscosity of the composition becomes too low, and when it exceeds 1,000,000, the viscosity of the composition becomes too high, and the coating properties are respectively high. Becomes insufficient. The vinyl group may be contained in an amount of 0.01% by weight or more, preferably 5.0% by weight or less.

<Polyorganosiloxane (B)>
The polyorganosiloxane (B) used in the present invention is a linear or branched polyorganosiloxane having vinyl groups at both ends and having a weight average molecular weight of 1 to 100,000. Used in conjunction with A). In particular, since the polyorganosiloxane (B) has a small molecular weight, it is used for exhibiting tackiness to the easy-adhesion layer formed on the easy-adhesion-treated film. Further, the polyorganosiloxane (B) is cured by an addition reaction with the following organohydrogensiloxane (C) and the curing catalyst (E), as in the case of the polyorganosiloxane (A), to give a silicon atom other than a vinyl group. The organic groups to be bonded may be different or the same. Specific examples thereof include a methyl group, an ethyl group, and a phenyl group. Specific examples include polydimethylsiloxane having vinyl groups at both ends. The weight average molecular weight of the polyorganosiloxane is preferably from 100,000 to 100,000 as measured by GPC, and when it is less than 10,000, the crosslink density becomes high and adhesion to a substrate such as glass becomes insufficient, and when it exceeds 100,000, the composition The viscosity becomes high and the coatability becomes insufficient.

<Polyorganohydrogensiloxane (C)>
The polyorganohydrogensiloxane (C) used in the present invention is a polyorganohydrogensiloxane having a hydrogen atom directly bonded to a silicon atom other than the terminal, and the viscosity is preferably 10 to 100 cSt/25°C. The polyorganohydrogensiloxane (C) is crosslinked and cured by the addition reaction of the above polyorganosiloxane (A) and polyorganosiloxane (B) and the curing catalyst (E). The silicon atom to which the hydrogen atom is directly bonded is preferably at a position other than the terminal in order to develop adhesiveness, and when the hydrogen atom is bonded to the silicon atom at the terminal, the hardness of the cured product becomes high and the peeling property becomes high. Becomes insufficient. If the viscosity is less than 10 cSt/25°C, the crosslink density will be low and the curability will be lowered, and if it exceeds 100 cSt/25°C, the crosslink density will be high and the adhesion to the base film will be low.

Further, the content of hydrogen atoms bonded to silicon atoms is preferably 1.0 mmol/g to 20.0 mmol/g, and when it is 1.0 mmol/g or more, curability is improved. If the content of hydrogen atoms is more than 20.0 mmol/g, the tack of the surface of the cured product will be too strong. In order to obtain good adhesiveness to the polyester film, the hydrogen atom content is more preferably 1.5 mmol/g or more. Examples of the organo group bonded to the silicon atom include a methyl group, an ethyl group and a phenyl group. The polyorganohydrogensiloxane may be, for example, linear or branched, and specific examples thereof include methylphenylhydrogenpolysiloxane.

<Curing catalyst (D)>
The curing catalyst (D) used in the present invention is used for causing an addition reaction between the polyorganosiloxane (A) and the polyorganosiloxane (B) and the polyorganohydrogensiloxane (C). A known metal, metal compound, metal complex or the like having a catalytic activity for the hydrosilylation reaction can be used. Particularly, it is preferable to use platinum, a platinum compound, or a complex thereof. These catalysts may be used alone or in combination of two or more. Moreover, you may use together a cocatalyst. The compounding amount of the curing catalyst (D) is preferably 1 ppm to 50 ppm, more preferably 5 to 20 ppm, based on the entire composition. If it is less than 1 ppm, the curability is deteriorated, and if it exceeds 50 ppm, it becomes a factor that the transparency of the cured product is decreased.

<Reactive functional group-containing hydrolyzable silane compound (E)>
The reactive functional group-containing hydrolyzable silane compound (E) used in the present invention is used in order to improve the adhesiveness over time to the easy-adhesion layer formed on the easy-adhesion-treated film or the untreated polyester film. For example, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4 -Epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane and the like can be used. The content of the reactive functional group-containing hydrolyzable silane compound (E) is 100 parts by weight of the total amount of the polyorganosiloxane (A), the polyorganosiloxane (B) and the polyorganohydrogensiloxane (C). On the other hand, 0.8 to 3.5 parts by weight is preferable, and if it is less than 0.8 parts by weight, the adhesiveness with time becomes insufficient, and if it exceeds 3.5 parts by weight, the adhesiveness to glass increases with time. The peelability becomes poor.

<Aluminum chelate compound (F)>
The aluminum chelate compound (F) used in the present invention acts as a condensation catalyst of the hydrolyzable group of the above-mentioned reactive functional group-containing hydrolyzable silane compound, and the time-dependent adhesiveness to glass increases, resulting in a peeling property. Used to prevent degradation. Specific examples thereof include ethyl acetoacetate aluminum diisopropylate, ethyl acetoacetate aluminum dibutyrate, diethyl acetoacetate aluminum butyrate, aluminum trisethylacetoacetate, alkyl acetoacetate aluminum diisopropylate, and the like, and two or more alone. May be used as a mixture. The blending amount of the aluminum chelate compound (F) is 0.08 to 0 relative to 100 parts by weight of the total blending amount of the polyorganosiloxane (A), the polyorganosiloxane (B) and the polyorganohydrogensiloxane (D). 0.35 parts by weight is preferable. If it is less than 0.08 parts by weight, the adhesiveness to glass increases with time and the releasability becomes insufficient, and if it exceeds 0.35 parts by weight, the adhesiveness to glass decreases with time. To do.

<Polyorganosiloxane (G)>
Polyorganosiloxane (G) used in the present invention, OH group content is from the general formula SiO _1/2 units and SiO _4/2 units in 0.1 to 5.0 wt%, SiO _1/2 units The molar ratio of /SiO _4/2 unit is 0.5 to 1.0, and it is used as a tackifier for improving the initial tackiness of the peelable silicone resin composition of the present invention with respect to glass. It can be added in order to suppress the increase in tackiness. If the OH content exceeds 5.0% by weight, the curability of the composition will deteriorate. If the molar ratio of SiO _1/2 unit/SiO _4/2 unit is less than 0.5 or more than 1.0, the improvement of the adhesive force may be insufficient.

In this composition, as an optional component, alkyne alcohol such as 3-methyl-1-butyn-3-ol, 3,5-dimethyl-1-hexyne-3-ol, ethynylcyclohexanol; 3-methyl- Enyne compounds such as 3-pentene-1-yne, 3,5-dimethyl-3-hexene-1-yne; 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane A reaction inhibitor such as 1,3,5,7-tetramethyl-1,3,5,7-tetrahexenylcyclotetrasiloxane, 1,3 divinyltetramethyldisiloxane, benzotriazole may be contained. This reaction inhibitor is added to 100 parts by weight of the total amount of the polyorganosiloxane (A), the polyorganosiloxane (B) and the polyorganohydrogensiloxane (C) as a content not to suppress the curability due to the addition reaction. On the other hand, it is preferably in the range of 0.0001 to 1 part by weight.

In addition, the present composition contains calcium carbonate, silica, talc, carbon black, titanium oxide, zinc oxide, kaolin, silicon dioxide, and melamine as optional components for adjusting viscosity and hardness, as long as the object of the invention is not impaired. It may contain inorganic fillers such as, and organic fillers, reinforcing materials such as glass fibers for reinforcing the cured resin, and hollow bodies such as shirasu balloons and glass balloons for weight reduction and viscosity adjustment. it can. In addition, antioxidants, organic pigments, fluorescent pigments, corrosion inhibitors, antioxidants and the like can be used as appropriate.

The release film according to claim 7 of the present invention is an easy-adhesion treated film in which a base film such as a polyester film is coated with a polyester resin having a hydroxyl value of 3 to 45 mgKOH/g to form an easy-adhesion layer. Or a release film having a silicone layer formed by applying the release silicone resin composition according to any one of claims 1 to 6 on the easy-adhesion layer. The peelable silicone resin composition according to any one of claims 1 to 6 was similarly applied to the untreated surface of the polyester film on which the easy-adhesion layer was not formed to form a silicone layer. It is a release film.

The thickness of the easy-adhesion layer of the easy-adhesion treated film is preferably in the range of 0.05 to 5.0 μm, and when the thickness is less than 0.05 μm, the easy-adhesion effect cannot be sufficiently obtained, and when it exceeds 5.0 μm, the easy-adhesion layer itself. Adhesiveness to the base film is reduced. As a coating method for the easily adhesive layer coating liquid and the silicone layer coating liquid, a multi-stage roll coater typified by a three-offset gravure coater or a five-roll coater, a direct gravure coater, a bar coater, an air knife coater, etc. are appropriately used. To be done. When the hydroxyl value of the polyester-based resin in the easy-adhesion layer is less than 3 mgKOH/g, it cannot be said that the film is an easy-adhesion-treated film having an easy-adhesion treatment, and the film is an untreated polyester film even if it is coated with a polyester resin. Included in the definition of. If the hydroxyl value of the polyester resin in the easy-adhesion layer exceeds 45 mgKOH/g, curing of the composition will be poor. The hydroxyl value serves as an index of the polarity of the easy-adhesion layer, and the higher the hydroxyl group, the higher the polarity, and the higher the adhesiveness between the present composition and the easy-adhesion layer.

After forming the silicone layer, a separator such as a resin film or coated paper may be further attached to the surface of the silicone layer in order to prevent the surface of the silicone layer from being soiled or attached to foreign matter and to improve the handling property of the release film.

Next, the peelable silicone resin composition of the present invention will be described in detail with reference to Examples and Comparative Examples.

<Examples and Comparative Examples>
As the polyorganosiloxane (A), a linear polydimethylsiloxane having a weight average molecular weight of 300 to 1,000,000 and a vinyl group bonded to a part of silicon atoms other than terminals (vinyl group content: 0.07 weight) %) as a polyorganosiloxane (a), a linear polydimethylsiloxane having a weight average molecular weight of 300 to 1,000,000 and a vinyl group at both ends (vinyl group content: 0.01% by weight), As the polyorganosiloxane (B), a linear polydimethylsiloxane having a weight average molecular weight of 1 to 100,000 is used as the polyorganohydrogensiloxane (C) having a viscosity of 10 to 100 cSt/25° C. and a silicon atom other than the terminal end. Polyorganohydrogen siloxane having hydrogen atoms directly bonded (hydrogen atom content 14 mmol/g), platinum-vinyl dimer complex (Pt: 0.2% wt) as a curing catalyst (D), reactive functional group-containing When 3-glycidoxypropyltrimethoxysilane is used as the hydrolyzable silane compound (E), aluminum trisethylacetoacetate is used as the aluminum chelate compound (F), and the OH group content is 1% by weight as the polyorganosiloxane (G). consists SiO _1/2 units / SiO _4/2 units, an MQ resin molar ratio of SiO _1/2 units / SiO _4/2 units is 0.7, the toluene as a solvent, ethynyl cyclohexanol as a reaction inhibitor Were used and mixed sufficiently with the formulation shown in Table 1 to obtain a uniform solution, which was used as a coating liquid for the peelable silicone resin compositions of Examples and Comparative Examples. Next, the coating liquid is applied onto the easy-adhesion layer of a 75 μm-thick polyester easy-adhesion treated film having an easy-adhesion layer in which a polyester resin having a hydroxyl value of 5 mgKOH/g is applied and cured on one side, A silicone layer is formed by coating the untreated surface of an untreated polyester film having a thickness of 75 μm and having a thickness after drying of 20 μm and curing at 130° C. for 90 seconds. A release film coated with the releasable silicone resin compositions of Examples and Comparative Examples was obtained.

<Evaluation item and evaluation method>

<Initial tackiness>
Each release film of Examples and Comparative Examples is formed into a strip shape of 2.5 cm×15 cm, and the silicone layer of the release film is adhered to a 5 cm×20 cm (thickness 0.25 cm) soda glass surface, which is defined in JIS Z0237. A 2 kg hand roller is reciprocated once on the release film to press-bond the silicone layer. After pressing, the 180-degree peel strength (mN/25 mm) is measured in accordance with JIS Z0237 at 23°C. If the peel strength is 5 mN or more/25 mm, it is judged to have sufficient adhesiveness, but in this evaluation, 10 mN or more/25 mm 50 mN or less/25 mm was evaluated as ◯, and other than this was evaluated as x.

<Adhesion after heating>
Each release film of Examples and Comparative Examples is formed into a strip shape of 2.5 cm×15 cm, and the silicone layer of the release film is adhered to a 5 cm×20 cm (thickness 0.25 cm) soda glass surface, which is defined in JIS Z0237. A 2 kg hand roller is reciprocated once on the release film to press-bond the silicone layer. After that, curing is performed for 14 days at 60° C. and 90% RH, and 180° peel strength (mN/25 mm) is measured at 23° C. according to JIS Z0237. A peel strength of 20 mN or more/25 mm 150 mN or less/25 mm was evaluated as ◯, and the others were evaluated as x.

<Initial adhesion with the easy-adhesion layer or a polyester film on which the easy-adhesion layer is not formed>
Each release film of Examples and Comparative Examples is formed into a strip shape of 2.5 cm×15 cm, and the silicone layer of the release film is adhered to a 5 cm×20 cm (thickness 0.25 cm) soda glass surface, which is defined in JIS Z0237. A 2 kg hand roller is reciprocated once on the release film to press-bond the silicone layer. Then, the release film is slowly peeled off, and the silicone layer of the release film is rubbed with a fingertip under the condition of 23°C. At this time, those in which the silicone layer was wholly peeled from the easy-adhesion layer were evaluated as x, those which were partially peeled were evaluated as Δ, and those which were not peeled were evaluated as ○.

<Adhesion property after heating with an easy-adhesion layer or a polyester film in which the easy-adhesion layer is not formed>
Each release film of Examples and Comparative Examples is formed into a strip shape of 2.5 cm×15 cm, and the silicone layer of the release film is adhered to a 5 cm×20 cm (thickness 0.25 cm) soda glass surface, which is defined in JIS Z0237. A 2 kg hand roller is reciprocated once on the release film to press-bond the silicone layer. Then, after curing at 60° C. and 90% RH for 21 days, the film is gradually cooled to 23° C., the release film is slowly peeled off, and the silicone layer of the release film is rubbed with a fingertip. At this time, those in which the silicone layer was wholly peeled from the easy-adhesion layer were evaluated as x, those which were partially peeled were evaluated as Δ, and those which were not peeled were evaluated as ○.

<Adhesive residue>
Each release film of Examples and Comparative Examples is formed into a strip shape of 2.5 cm×15 cm, and the silicone layer of the release film is adhered to a 5 cm×20 cm (thickness 0.25 cm) soda glass surface, which is defined in JIS Z0237. A 2 kg hand roller is reciprocated once on the release film to press-bond the silicone layer. Then, after curing at 60° C. and 90% RH for 21 days, the film is gradually cooled to 23° C., the release film is slowly peeled off, and the state of the glass surface is observed visually and by touch. The case where the glass surface did not have cloudiness or stickiness was evaluated as ◯, and the case where there was cloudiness or stickiness was evaluated as x.

<Evaluation result>
The evaluation results are shown in Table 2.

Claims (7)

The base film is a polyester film having a hydroxyl value of 3 to 45 mgKOH/g applied to at least one surface thereof to form an easy adhesion layer. A peelable silicone resin composition, which is applied to the surface on which the easy-adhesion layer is not formed,
A linear or branched polyorganosiloxane (A) having a vinyl group bonded to a silicon atom other than the terminal and having a weight average molecular weight of 300 to 1,000,000;
A linear or branched polyorganosiloxane (B) having vinyl groups at both ends and having a weight average molecular weight of 100,000 to 100,000;
A polyorganohydrogensiloxane (C) having a hydrogen atom directly bonded to a silicon atom other than the terminal,
A curing catalyst (D) necessary for the addition reaction,
A hydrolyzable silane compound (E) containing a reactive functional group,
An aluminum chelate compound (F),
A releasable silicone resin composition comprising: Furthermore, it has an OH group content of 0.1 to 5.0% by weight and is composed of SiO _1/2 units of general formula and SiO _4/2 units, and the molar ratio of SiO _1/2 units/SiO _4/2 units is 0.1. The peelable silicone resin composition according to claim 1, comprising a polyorganosiloxane (G) having a ratio of 5 to 1.0. The peelable silicone resin composition according to claim 1 or 2, wherein the reactive functional group-containing hydrolyzable silane compound (E) is 3-glycidoxypropyltrimethoxysilane. The peelable silicone resin composition according to any one of claims 1 to 3, wherein the aluminum chelate compound (F) is aluminum trisethylacetoacetate. The reactive functional group-containing hydrolyzable silane compound (E) was used in an amount of 0.1 parts by weight per 100 parts by weight of the total amount of the polyorganosiloxane (A), the polyorganosiloxane (B) and the polyorganohydrogensiloxane (C). The releasable silicone resin composition according to any one of claims 1 to 4, which comprises 8 to 3.5 parts by weight. The aluminum chelate compound (F) is 0.08 to 0.35 parts by weight based on 100 parts by weight of the total amount of the polyorganosiloxane (A), the polyorganosiloxane (B) and the polyorganohydrogensiloxane (C). The releasable silicone resin composition according to any one of claims 1 to 5, which comprises: An easy-adhesion layer formed by applying a polyester resin having a hydroxyl value of 3 to 45 mgKOH/g on at least one side of the base film to form an easy-adhesion layer, or on the easy-adhesion layer of the base film is a polyester film. A release film, comprising a silicone layer formed by applying the release silicone resin composition according to any one of claims 1 to 6 on a surface on which no layer is formed.