JP5201358B2 - Cationic polymerizable UV curable silicone composition and release substrate - Google Patents

Description

The present invention relates to a cationically polymerizable ultraviolet curable silicone composition release agent and a release substrate.

The release substrate is generally produced by forming a silicone release layer comprising a silicone release agent such as polyorganosiloxane on the substrate. As a base material, paper such as polyethylene laminated paper and glassine paper has been used for a long time, but in recent years, plastic films made from polyethylene, polypropylene, polyethylene terephthalate, and the like have been widely used.

When a plastic film is used as the base material, the demand is increasing year by year because it is superior in mechanical strength, transparency, dimensional stability, smoothness, cost, and the like as compared with the paper.

Silicone release agents applied on a substrate have release properties for adhesive substances, and can be classified into thermosetting, ultraviolet curable, electron beam curable silicone release agents, etc., depending on the curing method. Among these, UV curable silicone is advantageous in that it can be suitably applied to substrates such as plastic films and thermal papers that have poor heat resistance, is energy saving, has low equipment costs, and can be used in a small installation space. It has the following features.

In recent years, the use of plastic films is increasing because the quality is uniform and stable as a substrate, high smoothness, and thinning is possible, but the adhesion between plastic and cured silicone film is not always good. Therefore, the improvement of the adhesiveness with respect to the plastic of a silicone cured film is calculated | required.

As a method for improving the adhesion between the plastic and the cured silicone film, for example, a method of blending a silicone composition with a material such as a silane coupling agent having better adhesion to the plastic than the silicone resin has been proposed ( Patent Document 1). However, the film obtained by this method tends to have a heavy peel force.

In addition, a method for improving solvent friction resistance by providing a branched structure containing RSiO _3/2 units in the base polymer structure of a silicone resin has been proposed (see Patent Document 2). The film also tended to have a heavy peel force.

Furthermore, when plastic is used as the base material and when a solvent-based adhesive is used as the adhesive, the solvent-based adhesive is applied to the cured silicone film on the plastic. In particular, the cured silicone film was rubbed with a coating roll or the like, and the silicone dropped from the base material, resulting in a partial increase in peeling force. Therefore, a release agent composition capable of providing a silicone cured film excellent in resistance to friction (solvent friction resistance) in the presence of an organic solvent in addition to adhesion to a plastic has been demanded.

Japanese Patent Publication No.62-2986 JP 2003-26925 A

An object of the present invention is to provide a release agent composition that has excellent solvent friction resistance with respect to a base material and can be adjusted to any release performance even when a plastic film is used as the base material. .

As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by using a polyorganosiloxane having an epoxy group and a specific epoxy compound, and have completed the present invention.

That is, the present invention relates to (a) a polyorganosiloxane having at least two epoxy functional groups in one molecule, (b) an onium salt photoinitiator, and (c) one molecule represented by a predetermined general formula It contains a non-silicon unsaturated compound having an epoxy functional group and a hydroxyl group, and 0.1 to 5 parts by weight of component (b) and 0.1 part by weight of component (c) with respect to 100 parts by weight of component (a). The present invention relates to a cationically polymerizable ultraviolet curable silicone release agent composition characterized by being 1 to 8 parts by weight ; a release substrate having a cured layer of the cationically polymerizable ultraviolet curable silicone release agent composition on the substrate.

According to the present invention, even when a plastic film is used as a substrate, it is possible to provide a release agent composition that has excellent solvent friction resistance with respect to the substrate and can be adjusted to any release performance. .

The cationic polymerizable UV curable silicone release agent composition of the present invention comprises (a) a polyorganosiloxane having at least two epoxy functional groups in one molecule (hereinafter referred to as (a) component), (b) an onium salt. Cationic photopolymerization containing a photoinitiator (hereinafter referred to as component (b)) and (c) a non-silicon unsaturated compound having an epoxy functional group and a hydroxyl group in one molecule (hereinafter referred to as component (c)) It is characterized by comprising an ultraviolet curable silicone composition .

The component (a) used in the present invention is not particularly limited, and a known component can be used. The component (a) may be a linear polyorganosiloxane or a polyorganosiloxane having a branched structure in the molecule. Furthermore, the epoxy functional group in the molecule may be at the position inside the polyorganosiloxane main chain or at the terminal position. Specifically, for example, the general formula (1):

And the like. R in the general formula (1) represents an alkyl group having 1 to 10 carbon atoms, and X represents an epoxy functional group. R is not particularly limited, but is preferably a methyl group. The epoxy functional group (X) is not particularly limited as long as ring-opening cationic polymerization proceeds by an onium salt photoinitiator. For example, γ-glycidyloxypropyl group, β- (3,4-epoxycyclohexyl) Examples thereof include an ethyl group and a β- (4-methyl-3,4 epoxy cyclohexyl) propyl group. Moreover, m is an integer greater than or equal to 0 among the number of repeating units in the general formula (1), and n is an integer greater than or equal to 2. Although the repeating units m and n in the general formula (1) are described as block copolymers for convenience, the repeating units m and n are not necessarily block copolymers. Usually, in the general formula (1), the repeating units m and n are incorporated irregularly. Usually, the number m of repeating units is preferably an integer of 0 to 3,000, n is preferably an integer of 2 to 600, and n / (m + n) is preferably about 0.0001 to 0.5. .

The viscosity at 25 ° C. of the component (a) is preferably in the range of about 5 to 500,000 mPa · s, more preferably 10 to 10,000 mPa · s.

The component (b) used in the present invention is not particularly limited, and a known component can be used. Specifically, for example, (R ¹ ) ₂ I ⁺ X ⁻ , ArN ₂ ⁺ X ⁻ , (R ¹ ) ₃ S ⁺ X ⁻ (R ¹ represents an alkyl group and / or aryl group, Ar represents an aryl group, X ⁻ represents [B (C ₆ H ₅ ) ₄ ] ⁻ , [B (C ₆ F ₅ ) ₄ ] ⁻ , [B (C ₆ H ₄ CF ₃ ) ₄ ] ⁻ , [(C ₆ F ₅ ) ₂ BF ₂ ] ⁻ , [C ₆ F ₅ BF ₃ ] ⁻ , [B (C ₆ H ₃ F ₂ ) ₄ ] ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ , SbCl ₆ ⁻ , HSO ₄ ⁻ , ClO ₄ ^— or the like) is exemplified. Among these, (R ¹ ) ₂ I ⁺ X ⁻ (R ¹ represents an alkyl group and / or an aryl group, and X ⁻ represents [B (C ₆ H ₅ ) ₄ ] ⁻ , [ B (C ₆ F ₅ ) ₄ ] ⁻ , [B (C ₆ H ₄ CF ₃ ) ₄ ] ⁻ , [(C ₆ F ₅ ) ₂ BF ₂ ] ⁻ , [C ₆ F ₅ BF ₃ ] ⁻ and [B _{(C 6 H 3 F 2)} 4] -. represents an anion selected from the group consisting of), in the compounds represented are preferred.

The component (c) used in the present invention is a non-silicon unsaturated compound having an epoxy functional group and a hydroxyl group in one molecule, and the general formula (2):

(Wherein, a is an integer of 1 to 80, b is 1 to 100 integer, x is representing. An integer of 1 to 45) is a compound represented by. Moreover, you may use a commercial item as it is as (c) component. As a commercial item, Daipel Chemical Industry Co., Ltd. Epolide PB3600 etc. are mentioned, for example. Although the molecular weight of the component (c) is not particularly limited, it is usually preferable that the number average molecular weight is about 1,000 to 100,000 in terms of workability, and particularly 5,000 to 7,000. Is preferred. Further, the epoxy equivalent of the component (c) is not particularly limited, but is preferably about 125 to 333 g / eq (0.3 to 0.8 mol / 100 g) because the silicone peeling performance can be maintained. In particular, it is preferably 190 to 210 g / eq. In addition, in order to improve the reactivity of (c) component of this invention, you may use together a well-known photosensitizer. Specific examples of the photosensitizer include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2 , 4-diethylthioxanthone, 2,4-diisopropylthioxanthone and the like. Although the usage-amount in the case of using a photosensitizer is not specifically limited, Usually, it is preferable to use about 0.01-5 weight part of photosensitizers with respect to (c) component: 100 weight part.

The cationically polymerizable ultraviolet curable silicone release agent composition of the present invention may contain other components other than the components (a) to (c) as necessary. Examples of other components include polymerization inhibitors, antioxidants, ultraviolet absorbers, light stabilizers, solvents, antifoaming agents, leveling agents, and fluorine compounds. Moreover, you may contain well-known silicon compounds other than (a) component according to the objective in the range which does not deviate from the objective of this invention as needed.

The amount of (a) ~ (c) component in the cationically polymerizable ultraviolet curing silicone release agent composition of the present invention, (a) relative to 100 parts by weight of component, (b) component 0.1 to 5 parts by weight the degree is about 0.1 to 8 parts by weight component (c) is preferably, (a) relative to 100 parts by weight of component, (b) component 0.5 to 3 parts by weight, the component (c) 0 .5 to 3 parts by weight are used.

The release substrate of the present invention is usually produced by applying the cationic polymerizable ultraviolet curable silicone release agent composition according to the present invention to a substrate to form a release layer.

The base material used when producing the release base material is not particularly limited, and known materials can be used, and examples thereof include paper and plastic. Specific examples of the paper include polyethylene laminated paper, glassine paper, clay-coated paper, high-quality paper, coated paper, and synthetic paper. Examples of the plastic include molded products such as polypropylene, polyester, nylon, polystyrene, and polyethylene. In addition, the plastic molding can use the various molded object shape | molded with the injection molding machine etc. according to the use, and can also use what was shape | molded in the film form and the sheet form.

In order to form a peelable cured film using the cationic polymerizable UV curable silicone release agent composition of the present invention, this composition is applied to the surface of a substrate such as plastic or paper. The material may be directly coated on the surface of the substrate by a known method such as a Mayer bar, wire bar, blade coater, air knife coater, roll coater, etc., or the composition may be diluted with a soluble organic solvent. And may be applied. The organic solvent is not particularly limited and known ones can be used. Specific examples thereof include aromatic solvents such as toluene and xylene, aliphatic hydrocarbon solvents such as hexane and heptane, and ketones such as methyl ethyl ketone and acetone. Examples of the solvent include alcohol solvents such as isopropyl alcohol and n-butanol, ester solvents such as ethyl acetate and butyl acetate, and alicyclic solvents such as cyclohexane. These organic solvents may be used alone or in combination of several types having different polarities. The coating amount of the cationic polymerizable UV curable silicone release agent composition is not limited, but it is desired to be thinner from an economical viewpoint, and preferably 0.01 g / m ^{2 to} 20 g / m ^2. degree, and more preferably from ^{0.1g / m 2 ~0.5g / m 2} .

The cationically polymerizable UV curable silicone release agent composition of the present invention applied to the substrate by the above method is cured by a known UV curing system to give a release substrate.

The ultraviolet irradiation device used in the present invention is not particularly limited, and a known device can be used. Specifically, for example, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, a metal halide lamp, an ozone-less type with less ozone generation, or the like can be given. Usually, a plurality of lamps having an output of 30 W / cm or more are used in parallel.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. Parts and% in each example are based on weight unless otherwise specified.

Example 1
As a cationic polymerizable ultraviolet curable silicone release agent composition, (a) component “Silicolys UV POLY215” (trade name, active ingredient 100%, manufactured by Brewster Silicones) 100 parts by weight, (b) component “ 10 parts by weight of “Silicolys UV CATA211” (trade name, active ingredient 18%, manufactured by Blue Star Silicones Co., Ltd.) (e) “Epolide PB3600” (trade name, 100% active ingredient, manufactured by Daicel Chemical Industries, Ltd.) ) Is diluted with an organic solvent of ethyl acetate / isopropyl alcohol (IPA) = 50/50 (parts by weight) to a solid content of 10%. A coating solution was obtained. The coating solution is applied to a polyester film “Lumirror # 25S type” (manufactured by Toray Industries, Inc.) so as to have a solid content of 0.5 g / m ² , heat-treated at 60 ° C. for 10 seconds, and then irradiated with ultraviolet rays. The release substrate was prepared by irradiating with an ultraviolet irradiation amount of 25 mj / cm ² .

Example 2
A release substrate was obtained in the same manner as in Example 1 except that the amount of “Epolide PB3600” (manufactured by Daicel Chemical Industries, Ltd., active ingredient 100%) was changed to 5 parts by weight.

Comparative Example 1
In Example 1, a peeling substrate was obtained in the same manner as in Example 1 except that a coating solution prepared without using “Epolide PB3600” (manufactured by Daicel Chemical Industries, Ltd., 100% active ingredient) was used. It was.

Comparative Example 2
In Example 1, instead of “Epolide PB3600” (manufactured by Daicel Chemical Industries, Ltd., active ingredient 100%), “Celoxide 2021P” which is a non-silicon compound having an epoxy functional group but no hydroxyl group in one molecule. A release substrate was obtained in the same manner as in Example 1 except that a coating solution prepared using Daicel Chemical Industries, Ltd. (active ingredient 100%) was used.

Comparative Example 3
In Example 1, instead of “Epolide PB3600” (manufactured by Daicel Chemical Industries, Ltd., active ingredient 100%), “Denacol EX-” is a non-silicon compound having an epoxy functional group but no hydroxyl group in one molecule. A release substrate was obtained in the same manner as in Example 1 except that a coating solution prepared using “411” (manufactured by Nagase ChemteX Corporation, active ingredient 100%) was used.

Comparative Example 4
In Example 1, instead of “Epolide PB3600” (manufactured by Daicel Chemical Industries, Ltd., 100% active ingredient), one molecule has an epoxy functional group and a hydroxyl group, and has a carbon-carbon unsaturated double bond. A release substrate was obtained in the same manner as in Example 1 except that a coating solution prepared using non-silicon compound “EHPE 3150” (manufactured by Daicel Chemical Industries, Ltd., active ingredient 100%) was used. It was.

Comparative Example 5
In Example 1, instead of “Epolide PB3600” (manufactured by Daicel Chemical Industries, Ltd., active ingredient 100%), one molecule has a hydroxyl group and a carbon-carbon unsaturated double bond, and has an epoxy functional group. Peeling substrate in the same manner as in Example 1 except that a coating liquid prepared using “Poly bd R-15HT” (made by Idemitsu Kosan Co., Ltd., active ingredient 100%) is used. Got.

The following tests were performed on the release films obtained in Examples 1-2 and Comparative Examples 1-5. The results are shown in Table 1.

(Curability of silicone release agent composition)
The cured film surface of the silicone release agent composition immediately after production of the release film was rubbed with a finger and visually judged according to the following criteria. The results are shown in Table 1.
◯: Neither smear (the rubbed portion becomes cloudy) nor rub-off (the rubbed portion falls off) does not occur.
Δ: The surface is slightly affected, or the silicone is peeled off a little.
X: Smear or rub-off clearly occurs.

(Solvent friction resistance of silicone release agent composition)
Immediately after production of the release film, the surface of the cured film of the silicone release agent composition was rubbed back and forth 5 times with absorbent cotton impregnated with toluene, “Magic ink very thick (red)” (manufactured by Teranishi Chemical Industries, Ltd., trade name, oily A line was drawn with “Magic” and visually judged based on the degree of repellency of the ink of the silicone composition. The results are shown in Table 1.
○: The ink is repelled even in the rubbed area, and the silicone does not fall off.
(Triangle | delta): Some ink coloring is seen in the rubbed part, and there is some omission of silicone.
X: Coloring of the ink is observed on the entire rubbed portion, and the silicone is totally removed.

(Peeling power)
“Polyester adhesive tape No. 31B” (manufactured by Nitto Denko Corporation) was bonded to the cured film surface of the produced release film, and stored at 70 ° C. under a load of 25 g / cm ² for 20 hours. This was cut into a width of 25 mm, and a peeling speed of 0.3 m / min. The force (g / 25 mm) required to peel and peel the adhesive tape bonded together was measured.

(Residual adhesion rate)
“Polyester adhesive tape No. 31B” (manufactured by Nitto Denko Corporation, product name) was bonded to the surface of the cured film of the produced release film and stored at 70 ° C. under a load of 25 g / cm ² for 20 hours. After storage, the tape was peeled off and attached to a stainless steel plate (according to JIS C2107, hereinafter referred to as SUS plate) with a 2 kg rubber roller. Then, the tape was peeled from the SUS plate at an angle of 180 ° C. and a peeling speed of 0.3 m / min. The force (g / 25 mm) required for pulling and peeling was measured. As the blank, the peel force when the tape is directly bonded to the SUS plate and peeled under the same conditions is measured, and the ratio (%) of the former peel force to the latter peel force is obtained as the residual adhesion rate. This value indicates that the larger the value, the smaller the uncured portion of silicone, and the lower the adhesive strength of the tape due to the migration of silicone to the adhesive.

Claims (5)

(A) a polyorganosiloxane having at least two epoxy functional groups in one molecule, (b) an onium salt photoinitiator, and (c) an epoxy functional in one molecule represented by the following general formula (2) A non-silicon unsaturated compound having a group and a hydroxyl group, and 0.1 to 5 parts by weight of component (b) and 0.1 to 8 parts by weight of component (c) with respect to 100 parts by weight of component (a) A cationically polymerizable ultraviolet curable silicone release agent composition characterized by comprising:

(In the formula, a represents an integer of 1 to 80, b represents an integer of 1 to 100, and x represents an integer of 1 to 45.) (c) The cationic polymerizable ultraviolet curable silicone release agent composition according to claim 1, wherein the epoxy equivalent of the non-silicon unsaturated compound having an epoxy functional group and a hydroxyl group in one molecule is in the range of 125 to 333 g / eq. . (c) The number average molecular weight of the non-silicon unsaturated compound having an epoxy functional group and a hydroxyl group in one molecule is in the range of 1,000 to 100,000. The cationic polymerizable ultraviolet curable type according to claim 1 or 2 Silicone release agent composition. The peeling base material which has a hardening layer of the cationically polymerizable ultraviolet curable silicone release agent composition in any one of Claims 1-3 on a base material. The release substrate according to claim 4, wherein the substrate is a plastic film, sheet or paper.