JP2933744B2 - Curable silicone release agent and its separator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curable silicone release agent for forming a cured film having excellent balance between adhesiveness and releasability and excellent oil-based ink printability, and a separator having such a cured film.

[0002]

2. Description of the Related Art Conventionally, various types of release agents, such as silicone-based and long-chain alkyl-based, have been proposed as a release agent used for treating a back surface of an adhesive tape or forming a separator for protecting an adhesive surface. Since the release agent is easily re-peeled to the adhesive surface, the adhesion and release properties between the release agent film and its supporting substrate and the adhesive surface are moderate. It is required to be balanced. However, in each case, there was a problem that the balance between the adhesiveness and the peelability was poor. That is, for example, in the case of an adhesive tape, if the adhesive force to the adhesive surface is too high, there arises a problem that the tape cannot be stored for a long period of time or cannot be rewound when placed at a high temperature. On the other hand, if the adhesive force to the adhesive surface is too weak, there is a problem that the winding surface is displaced and the adhesive surface is contaminated. On the other hand, if the adhesive force to the supporting substrate is too weak, there is a problem that the adhesive tape is peeled off from the back surface and transferred to the adhesive surface.

[0003] In addition, the conventional silicone-based release agent has a problem that letters such as addresses cannot be written because the cured film repels oil-based ink.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a release agent for forming a silicone-based cured film having an excellent balance between adhesiveness and releasability and excellent oil-based ink printability, and a separator having such a cured film. Development is an issue.

[0005]

According to the present invention, there is provided a compound represented by the general formula: (Where R is an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, an aryl group or an aralkyl group, X is an epoxy-functional organic group, Y is a polyether / polymethylene group, and M / ( L + M + N) 0.05-90%
And N / (L + M + N) is 0.5 to 90%. ), A monomer having an epoxy functional group, a resin easily swellable or soluble in an organic solvent, a silicone-based graft copolymer, and an onium salt-based curing catalyst. The present invention provides a curable silicone-based release agent characterized by the following, and a separator provided with a cured film made of the curable silicone-based release agent on a supporting substrate.

[0006]

The polyorganosiloxane represented by the above general formula has excellent compatibility with an onium salt-based curing catalyst based on the polyether / polymethylene component contained in the molecule,
In addition, it exhibits good and stable ultraviolet curability or thermosetting together with a monomer having an epoxy functional group.

The monomer having an epoxy functional group contributes to the improvement of the balance between the adhesiveness and the peelability of the cured film to be formed. A resin that is easily swellable or easily soluble in an organic solvent is incorporated into a cured film to facilitate penetration of an oil-based ink, and contributes to improvement of printability. The silicone-based graft copolymer contributes to the improvement of the mixing and dispersing properties of the polyorganosiloxane, the monomer having an epoxy-based functional group, and the resin easily swellable or soluble in an organic solvent.

[0008]

Exemplary Curable Silicone Release Agents of the present invention comprise a polyorganosiloxane as a component. The polyorganosiloxane is represented by the following general formula.

R in the above general formula is an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, an aryl group or an aralkyl group. A methyl group is preferred from the viewpoint of peeling performance.

X in the above general formula is an epoxy-functional organic group. Examples thereof include the following. γ-glycidyloxypropyl group: β- (3,4-epoxycyclohexyl) ethyl group: β- (4-methyl-3,4-epoxycyclohexyl)
Propyl group:

Y in the above general formula is a polyether / polymethylene group. This group may be a polyether / polymethylene group-containing compound having good compatibility with the onium salt-based curing catalyst. Examples thereof include those represented by the following equation.

In the above formula, R ¹ is a polymethylene group. R ² represents an ethylene group: [—CH ₂ CH ₂ —], a propylene group: [—CH ₂ CH (CH ₃ ) —], or a butylene group:
_{[-CH 2 CH (C 2 H 5} ) - ] it is. R ³ is hydrogen or an alkyl group having 1 to 20 carbon atoms.

In the present invention, it is preferable that the polymethylene group (R ¹ ) is a trimethylene group: [—CH ₂ CH ₂ CH ₂ —] in terms of availability. Although the degree of polymerization (y) of the polyether portion depends on the content of the polyether / polymethylene group in the polyorganosiloxane, it is generally 2 to 2 from the viewpoint of improving the compatibility with the curing catalyst.
100 is suitable, and preferably 2 to 40.

In the above general formula, L, M and N mean the number of each structural unit. In the present invention, M / (L +
M + N) is 0.05-90% and N / (L + M + N) is 0.5-90%
90% is suitable. The M / (L + M + N) is 0.
If it is less than 05%, the resulting release agent will have poor curability,
If it exceeds 90%, the cured film formed has poor peeling performance. On the other hand, if N / (L + M + N) is less than 0.5%, the compatibility with the onium salt-based curing catalyst will be poor, and the resulting release agent will have poor curability. Peeling performance is poor.

The polyorganosiloxane represented by the above general formula has a number average molecular weight of 500 to 500,000, preferably 1000, in comparison with the preparation of a release agent that can be applied without using a solvent (solventless application). Those having a size of ~ 100,000 are preferably used.

The preparation of the polyorganosiloxane represented by the above general formula and having an epoxy-functional organic group and a polyether / polymethylene group in the molecule can be carried out, for example, by the following method.

That is, it has a predetermined number of unsubstituted hydrogens so that the content ratio of each structural unit is the above, and the remaining hydrogen is an alkyl group, a cycloalkyl group, an aryl group or an aralkyl group having 1 to 20 carbon atoms. A substituted polysiloxane and a predetermined amount of an epoxy group-containing compound having a functional group capable of reacting with hydrogen bonded to silicon or having an ethylenic double bond such as olefin glycidyl ether; By reacting with a predetermined amount of a polyether compound having an ethylenic double bond or a functional group capable of reacting with silicon-bonded hydrogen, an epoxy group-containing compound via unsubstituted hydrogen in the polysiloxane And a polyether compound by hydrosilylation or the like. That.

In the present invention, May be connected in a block shape or may be connected in a random state.

The curable silicone release agent of the present invention comprises:
A monomer having one or two or more epoxy functional groups is used as a component. Examples include the following.
Ethylene glycol diglycidyl ether: Glycerin diglycidyl ether: Vinyl cyclohexene dioxide: Limonenedioxide: 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexylcarboxylate: Bis- (6-methyl-3,4-epoxycyclohexyl) adipate:

One or two or more monomers having an epoxy functional group are used as in the case of other components. The compounding amount is 1 to 100 parts by weight of the polyorganosiloxane.
10,000 parts by weight is suitable, and preferably 10 to 1000 parts by weight. If the amount is less than 1 part by weight, the resulting release agent will have poor curability, and the cured film will have poor balance between adhesion and release properties. On the other hand, 100
If the amount exceeds 00 parts by weight, the formed cured film becomes poor in peeling performance.

The curable silicone-based release agent of the present invention contains a resin that is easily swellable or soluble in an organic solvent.
As the resin, those which swell or dissolve in organic solvents, particularly those used for oil-based inks, at 25 ° C. to room temperature are preferably used.

Examples of commonly used resins include ethyl cellulose, acrylic polymers, thermoplastic polyurethane, and thermoplastic polyester. Particularly preferred resins are acrylic polymers containing acrylic acid, methacrylic acid, or derivatives thereof.

Examples of such derivatives of acrylic acid or methacrylic acid include methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl Methacrylate, n-hexyl methacrylate, lauryl methacrylate, 2-hydroxyethyl acrylate,
Examples include hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, and polyethylene glycol monomethacrylate.

The resin which is easily swellable or soluble in an organic solvent is, for example, glycidyl methacrylate or another derivative of acrylic acid or methacrylic acid having an epoxy functional group. It may be a compound which is combined with an organosiloxane or an epoxy functional group-containing monomer so as not to drop off from the cured film.

In the present invention, as a resin easily swellable or soluble in an organic solvent, a resin having fluidity at room temperature, for example, having a viscosity of 500 to 200,000 at 25 ° C.
A release agent that can be coated without a solvent can be prepared by using 0 cp.

The low-molecular-weight acrylic polymer having fluidity at room temperature can be prepared, for example, by a polymerization method using a molecular weight modifier comprising a compound having a mercapto group or the like.

The amount of the resin easily swellable or soluble in the organic solvent is suitably from 1 to 5000 parts by weight, preferably from 10 to 100 parts by weight, per 100 parts by weight of the polyorganosiloxane.
0 parts by weight is preferred. If the amount is less than 1 part by weight,
The formed cured film has poor oil-based ink printability,
If it exceeds 5000 parts by weight, the cured film formed will have poor peeling performance. In addition, the viscosity of the obtained release agent is increased, so that the solvent-free coating property is easily hindered.

The curable silicone-based release agent of the present invention comprises a silicone-based graft copolymer as a component. Examples of the silicone-based graft copolymer include those obtained by copolymerizing a silicone macromonomer and a radical polymerizable monomer to form a graft form. An appropriate amount of the silicone-based graft copolymer is 0.1 to 10 parts by weight per 100 parts by weight of the resin easily swellable or soluble in an organic solvent.

As the silicone macromonomer, for example, a polyorganosiloxane having a radical polymerizable functional group such as a vinyl group, an acryloyl group, and a methacryloyl group at one end of a molecular chain is used. The silicone macromonomer component mainly contributes to the improvement in the mixing and dispersibility of the polyorganosiloxane represented by the above general formula.
Number average molecular weight 500-50,000, especially 1000-2
0000 is preferably used.

On the other hand, the radically polymerizable monomer component mainly contributes to the improvement of the mixing and dispersibility of a resin which is easily swellable or easily soluble in an organic solvent. Examples of the radical polymerizable monomer used include acrylic acid and methacrylic acid, or derivatives thereof, vinyl acetate, ethylene, propylene, vinyl chloride, vinylidene chloride, styrene and derivatives thereof,
And polyalkylene glycol monomethacrylate. Two or more kinds of such monomers are used as necessary.

The curable silicone release agent of the present invention contains an onium salt-based curing catalyst as a component. Known onium salt-based curing catalysts may be used. Examples thereof include a diazonium salt, a sulfonium salt represented by the following formula,
And iodonium salts. (However, Ar is an aryl group, R is an alkyl group or an aryl group, Z is BF ₄ , PF ₆ , AsF ₆ , SbF ₆ , SbC
l _6, a HSO _4, ClO ₄ of such non-basic and non-nucleophilic anion. )

The compounding amount of the onium salt curing catalyst is as follows: the polyorganosiloxane represented by the above general formula, a monomer having an epoxy functional group, and a resin which is easily swellable or soluble in an organic solvent. 0.1 to 100 parts by weight of
20 parts by weight is suitable, and 1 to 10 parts by weight is preferable.
If the amount is less than 0.1 part by weight, the resulting release agent has poor curability, and if it exceeds 20 parts by weight, the formed cured film may have poor release performance.

The preparation of the curable silicone-based release agent of the present invention is carried out by easily swelling or dissolving in the components used, that is, the polyorganosiloxane represented by the above general formula, a monomer having an epoxy functional group, and an organic solvent. , A silicone-based graft copolymer, an onium salt-based curing catalyst, and the like.

The order of mixing the above components is not particularly limited, but generally, a polyorganosiloxane, a monomer having an epoxy functional group and a silicone graft copolymer are preliminarily mixed and then easily mixed with an organic solvent. The order is such that a swellable or easily soluble resin is added and mixed, and then an onium salt-based curing catalyst is mixed.

In the above-mentioned mixing, when the resin which is easily swellable or soluble in the organic solvent to be used is solid, it may be used after being dissolved in a small amount of organic solvent. In this case, it is preferable to remove the organic solvent by volatilization after mixing.

When the resin which is easily swellable or easily soluble in the organic solvent to be used is an acrylic polymer, it may be added and mixed in the form of a monomer and then uniformly dispersed in the system while polymerizing it. Alternatively, they can be mixed by a method of using the monomer in a state of a monomer and converting it into a resin in a mixed system, such as a method of uniformly dispersing the monomer in the system while dropping and polymerizing the monomer.

In the curable silicone-based release agent of the present invention formed by mixing the components used, the resin which is easily swellable or soluble in an organic solvent is preferably in the form of particles and uniformly dispersed. It is preferable for adjusting the printing properties to oil-based ink and the viscosity that is advantageous for solvent-free coating. The particle diameter is 0.01 to from the viewpoint of the stability of the release agent and the dispersibility in the cured film.
About 10 μm is preferable.

The treatment for imparting releasability using the curable silicone release agent of the present invention can be performed in the same manner as a conventional curable silicone release agent. That is, for example, the substrate to be treated is coated using a suitable device such as a squeeze coater so that the coating amount is about 0.1 to 10 g / m ² , and the coated layer is subjected to a heat treatment or an ultraviolet ray. It can be carried out by curing by irradiation treatment or the like to form a film.

The substrate to be treated is not particularly limited. Generally, for example, paper, plastic laminated paper, cloth, plastic laminated cloth, plastic film, metal foil and the like are used. There is no particular limitation on the means for heating the coating layer or the means for irradiating ultraviolet rays. A heating means using hot air or the like, an ultraviolet irradiation means using an ultraviolet light source such as a high-pressure mercury lamp or a metal halide lamp, and the like are generally used.

The heating temperature for forming the cured film may be appropriately determined depending on the heat resistance of the base material.
0-200 ° C, especially 100-150 ° C. Also,
The irradiation amount of the ultraviolet ray may be appropriately determined based on the curing characteristics of the release agent. Further, the heat treatment and the ultraviolet irradiation treatment may be used in combination.

In the separator of the present invention, such a cured film is provided on one side or both sides of a supporting substrate. This is adhered to an adhesive surface of a double-sided adhesive tape or the like, and is used for the purpose of protecting the adhesive surface until it is put to practical use. The curable silicone-based release agent of the present invention can be used for various purposes other than the above-mentioned separators, for example, for back surface treatment of an adhesive tape.

[0042]

The curable silicone release agent of the present invention is
It has excellent curability by heat or ultraviolet light, and its cured film is excellent in balance between adhesiveness and releasability and printability with oil-based ink.

[0043]

EXAMPLES Reference Example 1: Preparation of polyorganosiloxane In a glass three-necked flask equipped with a stirring blade, a thermometer, and a dropping funnel, 33.5 parts (parts by weight, hereinafter the same) of 4-vinylcyclohexene monoxide and polyethylene were added. Glycol allyl methyl ether (number average molecular weight 450) 1
A solution prepared by dissolving 21.5 parts in 200 parts of ethyl acetate was added, and the mixture was stirred for 30 minutes under a stream of dry nitrogen, and then added with a platinum catalyst (platinum-vinylsiloxane complex salt) for hydrosilylation.
The mixture was stirred for an additional 10 minutes and the system was warmed to 40 ° C. Next, 100 parts of a polydimethylmethylhydrogensiloxane copolymer having a number average molecular weight of 2,000 was gradually dropped into the system heated to 40 ° C. under stirring over about 1 hour. At 75 ° C.
Allowed to react for hours. The polydimethylmethylhydrogensiloxane copolymer used is represented by the following formula. In the above formula, the arrangement of the following structural units is random.

The reaction solution obtained above was placed in a vacuum drier, and ethyl acetate was dried to obtain the desired product. As a result of infrared absorption spectrum and NMR spectrum analysis, the obtained product had the following molecular structure. Its number average molecular weight was 4,700. In the above formula, the arrangement of the following structural units is random.

Reference Example 2 Preparation of Acrylic Polymer 30 equipped with a cooling pipe, a stirrer, a thermometer, and a nitrogen gas introducing pipe.
In a 0 cc four-necked flask, add n-butyl acrylate 9
0 parts, 10 parts of glycidyl methacrylate, 1 part of 1-dodecanethiol, 0.2 part of 2,2'-azobisisobutyronitrile, and 25 parts of toluene. The mixture was heated to 65 ° C. to start polymerization, and reacted at 65 ° C. for 2 hours and then at 75 ° C. for 2 hours to obtain a target product. The obtained acrylic polymer had a number average molecular weight (hereinafter the same) of 13,000 based on polystyrene conversion by gel permeation chromatography.

Reference Example 3 Preparation of Silicone Graft Copolymer In a four-necked flask equipped with a cooling tube, a stirrer, a thermometer, and a nitrogen gas inlet tube, a silicone macromonomer having a number average molecular weight of 5000 shown below was placed. 45 parts, 45 parts of n-butyl acrylate, 10 parts of glycidyl methacrylate, 1 part of 1-dodecanethiol, 0.2 part of 2,2'-azobisisobutyronitrile and 25 parts of toluene are added, and the mixture is purged with nitrogen for about 1 hour under stirring. After that, heat the system to 65 ° C.
At 65 ° C. for 2 hours, then 7
The reaction was carried out at 5 ° C. for 2 hours to obtain the desired product. The obtained silicone-based graft copolymer has a number average molecular weight of 15
000.

Example 1 50 parts of the polyorganosiloxane obtained in Reference Example 1, 3, 4
100 parts of -epoxycyclohexylmethyl-3 ', 4'-epoxycyclohexylcarboxylate and 1 part of the silicone-based graft copolymer obtained in Reference Example 3 were sufficiently stirred and mixed with a homogenizer, and then the acrylic obtained in Reference Example 2 was added thereto. 50 parts of the system polymer were sequentially mixed with stirring by a homogenizer to obtain a milky white homogeneous mixture. Next, after drying a small amount of toluene contained in a vacuum dryer, 10 parts of an ultraviolet-curable sulfonium salt-based curing catalyst was added, and the mixture was sufficiently stirred and mixed to obtain a curable silicone-based release agent of the present invention.

The release agent was applied to the polyethylene surface of a 120 μm-thick polyethylene laminated kraft paper with a squeeze coater so that the coating amount was 1 g / m ^2, and an ultraviolet irradiation device equipped with a high-pressure mercury lamp was used. The coated surface was irradiated and cured (500 mJ / cm ² ) to obtain a separator.

Example 2 Into a four-necked flask equipped with a cooling tube, a stirrer, a thermometer, and a nitrogen gas inlet tube, 50 parts of the polyorganosiloxane obtained in Reference Example 1, 3,4-epoxycyclohexylmethyl-
3 ', 4'-epoxycyclohexylcarboxylate 5
0 parts, methyl methacrylate 45 parts, glycidyl methacrylate 5 parts, 1-dodecanethiol 0.5 part, 2,2 ′
0.1 part of azobisisobutyronitrile and 1 part of a silicone-based graft copolymer (manufactured by Toagosei Chemical Co., Ltd .: GS-30, the same applies hereinafter) were added, and the system was replaced with nitrogen for about 1 hour with stirring. The polymerization was started by heating to 65 ° C.
The mixture was reacted at 75 ° C. for 2 hours to obtain a milky white homogeneous mixture, to which 7.5 parts of an ultraviolet-curable sulfonium salt-based curing catalyst was added, and the mixture was thoroughly stirred and mixed to obtain a cured mixture of the present invention. A silicone-based release agent was obtained, and a separator was obtained using the same in the same manner as in Example 1.

Example 3 Into a four-necked flask equipped with a cooling pipe, a stirrer, a thermometer, and a nitrogen gas inlet pipe, 50 parts of the polyorganosiloxane obtained in Reference Example 1, 3,4-epoxycyclohexylmethyl-
3 ', 4'-Epoxycyclohexylcarboxylate 1
Then, with stirring, the mixture was replaced with nitrogen for about 1 hour while stirring. Next, the above system was heated to 65 ° C, and 27 parts of ethyl acrylate, 3 parts of glycidyl methacrylate, 1-
A mixture of 0.3 parts of dodecanethiol and 0.06 parts of 2,2'-azobisisobutyronitrile was added dropwise over about 2 hours to polymerize the mixture, followed by heating at 75 ° C for 2 hours to give a milky white color. A homogeneous mixture was obtained, and 9 parts of a UV-curable sulfonium salt-based curing catalyst was added thereto. The mixture was thoroughly stirred and mixed to obtain a curable silicone-based release agent of the present invention. A similar separator was obtained.

Comparative Example 5 parts of an ultraviolet-curable sulfonium salt-based curing catalyst was added to 95 parts of the polyorganosiloxane obtained in Reference Example 1, and the mixture was thoroughly stirred and mixed to obtain a silicone-based release agent. A separator was obtained according to Example 1.

Evaluation Test The following characteristics were examined for the separators obtained in the examples and comparative examples. Curability The stickiness on the surface of the separator provided with releasability was evaluated, and the evaluation was evaluated as ○ when there was no stickiness, Δ when there was a little stickiness, and X when the stickiness was large.

The peelability of the separator at 20 ° C. and 65% RH was given to
A commercially available adhesive tape having a width of 25 mm (Kraft Tape No. 7170, manufactured by Nitto Denko Corporation) was pressed and reciprocated with a rubber roller weighing 2 kg once, and a pressure of 50 g / cm ² was applied to the adhesive tape under a pressure of 20 g. Leave at 48 ° C for 48 hours. afterwards,
Release the load and leave the product at 20 ° C and 65% RH for 2 hours.
The film was peeled off at a speed of 0 mm / min (peel at 180 °), and the force required for the peeling was measured.

Residual Adhesion Rate (Non-Staining Property of Adhesive Surface)
At 5% RH, the surface was thoroughly polished with a stainless steel plate (SUS27CP) water-resistant abrasive paper (No. 280).
The force required for peeling was measured in the same manner as described above for the sample left for 0 minutes. Then, the ratio of the residual adhesive force of the obtained measured value to the measured value of the pressure-sensitive adhesive tape which was not brought into contact with the releasability-imparting surface in the same manner as described above was calculated as the residual adhesive ratio.

Printability Using a commercially available oil-based ink pen, write a letter on the releasability-imparting surface. ◎: no cissing, を: almost no cissing, Δ: slight cissing, Δ: almost cissing It evaluated as x.

The results are shown in Table 1. Comparative Example 2 in the table is an evaluation result of the polyethylene laminated kraft paper used for forming the separator.

[Table 1]

As can be seen from Table 1, the examples using the release agent of the present invention are excellent in curability in all cases, and the cured film is excellent in the balance between adhesiveness and releasability, and excellent in oil-based ink printability. You can see that it is.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ identification symbol FI C09D 183/06 C09D 183/06 (58) Field surveyed (Int.Cl. ⁶ , DB name) C09J 7/02-7/04 C08G 59/20-59/30 C08L 63/00 C09D 151/08 C09D 183/06 WPI / L (QUESTEL)

Claims (2)

(57) [Claims] 1. The general formula: (Where R is an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, an aryl group or an aralkyl group, X is an epoxy-functional organic group, Y is a polyether / polymethylene group, and M / ( L + M + N) 0.05-90%
And N / (L + M + N) is 0.5 to 90%. ), A monomer having an epoxy functional group, a resin easily swellable or soluble in an organic solvent, a silicone-based graft copolymer, and an onium salt-based curing catalyst. A curable silicone-based release agent characterized by the following. 2. A separator having a cured film comprising the curable silicone-based release agent according to claim 1 provided on a supporting substrate.