UV-curable silicone release agent composition

Abstract

To obtain an ultraviolet-curable silicone release agent composition which has low viscosity and achieves both good thin film coatability and film strength durable for practical use.SOLUTION: The ultraviolet-curable silicone release agent composition contains 40-95 pts.mass of an organopolysiloxane (A) having a viscosity at 25°C of 10-1,000 mPa s and having at least two cationically polymerizable groups in one molecule, 5-60 pts.mass of a compound (B) represented by general formula (1), and 0.5-10 pts.mass of a photocationic polymerization initiator (C). The ultraviolet-curable silicone release agent composition has a viscosity at 25°C of 10-100 mPa s.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to an ultraviolet-curable silicone release agent composition that has low viscosity, good thin-film coating properties, and film strength sufficient for practical use. [Background technology]

[0002] UV-curable compositions can be broadly classified into two types: one in which an initiator that generates radicals when irradiated with UV light is added, and the reaction proceeds using these radicals as the active species; and another in which an initiator that generates cationic species when irradiated with UV light is added, and the reaction proceeds using these cationic species as the active species. The former can polymerize compounds having (meth)acrylic groups, vinyl groups, etc., while the latter can polymerize compounds having epoxy groups, oxetanyl groups, vinyl ether groups. It is widely known that the former is affected by oxygen inhibition, resulting in an unhardened surface and a tendency for surface tack to remain, while the latter is not affected by oxygen inhibition, resulting in a completely hardened surface and no surface tack. As UV-curable silicone compositions, compositions in which the reaction proceeds in both of these conditions are commercially available. Patent Document 1 describes the latter, and is a publication that polymerizes a silicone containing epoxy groups. There was room for improvement in order to obtain good thin-film coating properties. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Special Publication No. 56-38350 [Patent Document 2] Japanese Patent Publication No. 2010-215847 [Patent Document 3] International Publication No. WO2018 / 079337 [Patent Document 4] Japanese Patent Publication No. 2018-188618

[0004] Patent Document 2 is a publication relating to a release agent composition that has excellent solvent friction resistance to a substrate even when a plastic film is used as the substrate, and whose release performance can be adjusted to any desired level. Like Patent Document 1, Patent Document 2 also had room for improvement in order to obtain good thin-film coating properties. Patent Document 3 aims to provide a novel release sheet with good peelability, but there was room for improvement in film strength.

[0005] Patent document 4 is a publication relating to an ultraviolet-curable composition capable of producing a sealing material for an organic EL light-emitting device that combines transparency and hygroscopicity, a method for manufacturing an organic EL light-emitting device using this ultraviolet-curable composition, and an organic EL light-emitting device. No studies were conducted on its use as a release agent. [Overview of the project] [Problems that the invention aims to solve]

[0006] The objective is to obtain an ultraviolet-curable silicone release agent composition that has low viscosity, good thin-film coating properties, and film strength sufficient for practical use. [Means for solving the problem]

[0007] This is an ultraviolet-curable silicone release agent composition containing 40 to 95 parts by mass of an organopolysiloxane (A) having a viscosity of 10 to 1,000 mPa·s at 25°C and having at least two cationic polymerizable groups in one molecule, 5 to 60 parts by mass of a compound (B) represented by general formula (1), and 0.5 to 10 parts by mass of a photocationic polymerization initiator (C), with a viscosity of 10 to 100 mPa·s at 25°C. [Effects of the Invention]

[0008] This invention provides a cationic silicone-based release agent composition that achieves both good thin-film coating properties due to its low viscosity and film strength sufficient for practical use, as well as release paper and separator films using the same. [Modes for carrying out the invention]

[0009] The following describes in detail the UV-curable silicone release agent composition according to the present invention, which has low viscosity, good thin-film coating properties, and film strength that is suitable for practical use.

[0010] <Organopolysiloxane (A) having a viscosity of 10 to 1,000 mPa·s at 25°C and containing at least two cationic polymerizable groups per molecule> Organopolysiloxane (A), having a viscosity of 10 to 1,000 mPa·s at 25°C and possessing at least two cationic polymerizable groups in one molecule, is a silicone compound having cationic polymerizable groups. Examples of cationic polymerizable groups include epoxy groups, oxetanyl groups, vinyl ether groups, etc. A more preferred cationic polymerizable group is the epoxy group. Examples of epoxy groups include glycidyl groups, epoxycyclohexyl groups such as 3,4-epoxycyclohexyl groups, and alicyclic epoxy groups such as epoxymethylcyclohexyl groups such as 3,4-epoxy-4-methylcyclohexyl groups.

[0011] From a reactivity standpoint, compounds having alicyclic epoxy groups are preferred. A viscosity of 10 to 1,000 mPa·s is preferable. If the viscosity is below 10 mPa·s, repulsion may occur on the substrate. If it exceeds 1,000 mPa·s, the viscosity of the composition is too high, and the coating properties will decrease. Oily silicone compounds having cationic polymerizable groups mainly in a linear structure are preferred. Crosslinked structures are acceptable as long as they meet the viscosity range. Multiple types of organopolysiloxane (A) can be used in combination.

[0012] The amount of organopolysiloxane (A) added, which has a viscosity of 10 to 1,000 mPa·s at 25°C and contains at least two cationic polymerizable groups in one molecule, is 40 to 95 parts by mass, more preferably 50 to 93 parts by mass, per 100 parts by mass of the total of organopolysiloxane (A) and compound (B) represented by general formula (1).

[0013] <Compound (B) represented by General Formula (1)> Among the compounds (B) represented by General Formula (1), R 1 is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms containing a cationic polymerizable group, and R 2 is independently an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms not containing a cationic polymerizable group, and n is an integer of 0 to 3. R 1 From the viewpoint of reactivity during cationic polymerization, an epoxy group is more suitable than a vinyl ether group or an oxetanyl group, and among epoxy groups, an alicyclic epoxy group is more suitable. Also, R 2 includes a methyl group, an ethyl group, a propyl group, a butyl group, an isopropyl group, an isobutyl group, a tert-butyl group, a hexyl group, an octyl group, a 2-ethylhexyl group, a cyclohexyl group, a phenyl group, a tolyl group, etc., or a group in which part or all of hydrogen atoms are substituted with a hydroxy group, an amino group, a halogen atom, etc., and a methyl group or a phenyl group is more suitable. The compound (B) represented by General Formula (1) is a component that reduces the viscosity of the composition and improves the film strength. The addition amount of the compound (B) represented by General Formula (1) is such that the viscosity at 25 °C is 10 to 1,000 mPa·s and it is 5 to 60 parts by mass, more preferably 7 to 55 parts by mass, with respect to a total of 100 parts by mass of the organopolysiloxane (A) having at least 2 cationic polymerizable groups in one molecule and the compound (B) represented by General Formula (1). If the addition amount is less than 5 parts by mass, a sufficient low-viscosity effect of the composition cannot be obtained, and a cured product cannot obtain sufficient film strength either. If it exceeds 60 parts by mass, the peel strength of the cured product decreases and the performance as a release agent deteriorates.

[0014] Among the compounds (B) represented by General Formula (1), a more suitable material is the compound represented by General Formula (2). Incidentally, X 1 and X 2 are both alkylene groups represented by having 1 to 5 carbon atoms.

[0015] <Photo cationic polymerization initiator (C)> The photo cationic polymerization initiator (C) is a photo initiator for curing the composition. An onium salt-based photo initiator capable of generating cationic species by ultraviolet irradiation is preferred. From the compatibility and curability with the composition, it has a dibis[4-alkylphenyl]iodonium structure as a cation and SbF 6- , PF 6- , BF 4- , B(C6F5) 4- and the like are preferred. As the addition amount of the photo cationic polymerization initiator (C), based on a total of 100 parts by mass of the organopolysiloxane (A) having a viscosity at 25 °C of 10 to 1,000 mPa·s and having at least 2 cationic polymerizable groups in one molecule and the compound (B) represented by the general formula (1), it is 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass. If it is less than 0.1 part by mass, curing is insufficient, and if it is more than 10 parts by mass, it has an adverse effect on the surface state of the cured film and the release characteristics deteriorate.

[0016] The appropriate viscosity at 25 °C of the ultraviolet curable silicone release agent composition of the present application is 10 to 100 mPa·s, more preferably 20 to 90 mPa·s. If it exceeds 100 mPa·s, good thin film coating properties cannot be obtained, and if it is less than 10 mPa·s, the curability decreases.

[0017] The ultraviolet curable silicone release agent composition of the present application may be applied to a plastic film or the like, irradiated with ultraviolet rays and cured, and used as a separator film. As the material of the plastic film serving as the base material, in general-purpose products, polyesters such as polyethylene terephthalate (PET), polyethylene, polypropylene, nylon, and depending on the application, polyethylene naphthalate, liquid crystal polymer, polyphenylene sulfide, polyether ether ketone, polyimide, polyether imide, etc. may also be used. In order to improve the adhesion between these plastic films and the ultraviolet curable silicone release agent composition, a sheet-like base material such as a plastic film subjected to primer treatment, corona treatment, etching treatment, plasma treatment, etc. may be used.

[0018] For applying the UV-curable silicone release agent composition to the plastic film substrate, known methods such as roll coating, gravure coating, wire doctor coating, air knife coating, and dipping coating can be used. The coating amount can be 0.01 to 100 g / m². 2 More preferably 0.05-50 g / m 2 That is the case. A plastic film coated with an ultraviolet-curable silicone release agent composition can be easily cured by irradiating it with ultraviolet light. Suitable ultraviolet light sources include high-pressure mercury lamps, medium-pressure mercury lamps, low-pressure mercury lamps, metal halide lamps, and mercury arc lamps. [Examples]

[0019] Next, the ultraviolet-curable silicone release agent composition of the present application will be described in detail with reference to examples and comparative examples.

[0020] <Viscosity measurement> The viscosity at 23°C of the silicone materials used in the examples and comparative examples, and the UV-curable silicone release agent compositions of Examples 1-4 and Comparative Examples 1-5, was measured using a Type B viscometer (Toki Sangyo TVB-25M). The criteria for judging UV-curing silicone release agent compositions were that a viscosity within the range of 10 to 100 mPa·s was acceptable, while any other range was unacceptable. The results are shown in Tables 3 and 4.

[0021] <Preparation of separator film> A UV-curing silicone release agent composition is applied to a PET film (Toray Industries, Ltd., product name: Lumirror 75U483) at a rate of approximately 0.5 g / m². 2 Apply the coating in this manner and use a high-pressure mercury lamp to measure 80 mJ / cm². 2 A separator film was fabricated by irradiating it with ultraviolet light at a specified intensity.

[0022] <Peeling force> In the preparation of the separator film, an adhesive tape (product name: Nitto 31B Tape, manufactured by Nitto Denko) was applied to the cured surface of the UV-curable silicone release agent composition of the separator film and pressed down once back and forth with a 2kg roll. The peeling force of the adhesive tape was determined by peeling the tape off at a speed of 0.3 m / min in a 180-degree direction under conditions of room temperature of 23°C and humidity of 50%. The passing criterion was 10-200 mN / 25 mm. The results are shown in Tables 3 and 4.

[0023] <Coating strength> The surface of the UV-curable silicone release agent composition-cured separator film was rubbed 10 times with a finger, and the presence or absence of clouding (smearing) and peeling off of the release agent layer (rubbing off) was visually checked. The film strength of the release agent layer was then evaluated according to the following criteria. The criteria for evaluation were as follows: if neither smearing nor love-off was observed, it was a pass (:○); if at least one of smearing or love-off was observed, it was a fail (:×). The results are shown in Tables 3 and 4.

[0024] <Preparation of the UV-curable silicone release agent composition of Example 1> EpMe2SiO 1 / 2 Unit: Me2SiO 2 / 2 90 g of an oily polysiloxane (a-1) consisting of units and exhibiting a viscosity of 47 mPa·s at 25°C, and 10 g of a compound (b-1) represented by the following formula (4) were stirred until homogeneous. To this mixture, 2 g of a bis-[4-n alkyl(C10~C13)phenyl]iodonium tetrakispentafluorophenylboric acid solution, dissolved at 50% by mass in propylene carbonate, was stirred and mixed until homogeneous to obtain the ultraviolet-curable silicone release agent composition of Example 1. Furthermore, Ep has the structure shown in formula (3) below, and Me represents a methyl group. JPEG0007900160000001.jpg1733 ...(3) JPEG0007900160000002.jpg2270 ...(4)

[0025] <Preparation of UV-curable silicone release agent compositions for Examples 2 and 3, and Comparative Examples 1 and 3> The ultraviolet-curable silicone release agent compositions for Examples 2 and 3, and Comparative Examples 1, 2, and 3 were prepared in the same manner as in Example 1, except that the amounts of (a-1) and (b-1) in Example 1 were changed to those shown in Tables 1 and 2.

[0026] <Preparation of UV-curable silicone release agent compositions for Example 4 and Comparative Example 2> In Example 1, component (a-1) is Me3SiO 1 / 2 Unit, EpMeSiO 2 / 2 Unit: Me2SiO 2 / 2 The UV-curable silicone release agent compositions of Example 4 and Comparative Example 2 were prepared in the same manner as in Example 4 and Comparative Example 2, except that the oily polysiloxane (a-2) consisting of units and exhibiting a viscosity of 100 mPa·s at 25°C was used, and the amount of additive was as described in Table 1.

[0027] <Preparation of the UV-curable silicone release agent composition of Comparative Example 4> Comparative Example 4, an ultraviolet-curable silicone release agent composition, was prepared in the same manner as in Example 1, except that component (b-1) was replaced with component (b-2) of formula (5) below, which is an epoxy compound that does not contain silicon atoms, and the amount added was as shown in Table 1. Since the composition of Comparative Example 4 separated into two layers due to mismatch, viscosity measurement, release force, and film strength evaluation were not performed. JPEG0007900160000003.jpg2154 ...(5)

[0028] <Preparation of the UV-curable silicone release agent composition of Comparative Example 5> Comparative Example 5, an ultraviolet-curable silicone release agent composition, was prepared in the same manner as in Example 1, except that component (b-1) was replaced with component (b-3) of formula (6), which is an epoxy compound that does not contain silicon atoms, and the amount added was as shown in Table 1. JPEG0007900160000004.jpg2745 ...(6)

[0029] Table 1

[0030] Table 2

[0031] Table 3

[0032] Table 4

Claims

1. 40 to 95 parts by mass of organopolysiloxane (A) having a viscosity of 10 to 1,000 mPa·s at 25°C and having at least two cationic polymerizable groups in one molecule, Compound (B) represented by the following general formula (2) is used in a mixture of 5 to 60 parts by mass. ・・・（２） (X1 and X2 are both alkylene groups with 1 to 5 carbon atoms.) It contains 0.5 to 10 parts by mass of a photocationic polymerization initiator (C), A UV-curable silicone release agent composition having a viscosity of 10 to 100 mPa·s at 25°C.

2. The organopolysiloxane (A) has a viscosity of 10 to 1,000 mPa·s at 25°C and contains at least two cationic polymerizable groups in one molecule, and the cationic polymerizable groups are alicyclic epoxy groups. X of the compound represented by general formula (2) １ , X ２ It is an ethylene group, The ultraviolet-curable silicone release agent composition according to claim 1, wherein the photocationic polymerization initiator (C) is a bis-[4-alkylphenyl]iodonium salt compound.

3. The ultraviolet-curable silicone release agent composition according to claim 1 or 2, characterized in that it does not contain an epoxy compound that does not contain silicon atoms.

4. A separator prepared using the ultraviolet-curable silicone release agent composition described in any one of claims 1 to 3.

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