JP2554924B2 - Silicone releasable coating, its adhesive member and separator - Google Patents

Description

TECHNICAL FIELD The present invention has a multi-layer structure in which a layer made of an easily swellable or easily soluble resin is added to a silicone film layer, and the oil-based ink printability and peeling property are improved. The present invention relates to an excellent silicone-based releasable coating, and its adhesive member and separator.

Background of the Invention It has been dealt with by treating the back surface of a supporting base material in an adhesive member such as an adhesive tape with a release agent so that the adhesive surface can be easily peeled off from the back surface of the base material. Similarly, it is desirable to be able to print because of the need for address writing.

Conventionally, as a printable silicone-based peelable film,
It has been known that a special polysiloxane is mixed with fine powder silica or ethyl cellulose (Japanese Patent Laid-Open Nos. 59-126475 and 59-147048). However, there is a fatal problem that the curing of the polysiloxane is hindered by the mixture, and the peeling property of the formed film is significantly reduced.

On the other hand, a silicone-based releasable coating obtained by ultraviolet-curing a polyorganosiloxane containing an epoxy group-functional component in its molecule using an onium salt-based curing catalyst has been known (JP-A-56-38350, the same publication). 60-47064). This is because it enables solvent-free coating of release agents, and is environmentally friendly.
It provides safety against flames, energy saving, and efficiency of peeling treatment. However, it does not have printability with oil-based ink. Further, the film is apt to be insufficiently cured, and a large amount of ultraviolet ray irradiation is required to cure it to a practical level, and even in that case, the peeling property of the peelable film formed is likely to vary. Therefore, there is a problem that the adhesive surface adhered to this is contaminated and the adhesive strength is reduced.

PRIOR ART AND PROBLEMS The present inventors have previously proposed a silicone-based releasable coating film comprising a release agent containing a polyorganosiloxane having a polyether / polymethylene group introduced in the molecule (Japanese Patent Application No. 62-235094). ). This has good curability of the film, excellent peeling performance, and printability with oil-based ink.

However, in various applications of adhesive members and separators, such as adhesive tapes for packaging, it may be desired that the printability is further improved.

Means for Solving the Problems The present invention, by forming a film having a multi-layer structure using a special film-forming resin, without deteriorating the release characteristics of the silicone-based releasable film, its printability It was intended to improve.

That is, the present invention comprises a silicone coating layer on an ink affinity layer made of a film-forming resin that is easily swellable or soluble in an organic solvent, and the silicone coating layer has the general formula (However, 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 / ( 1 + m + n) is 0.05 to 90%, and n / (l + m + n) is 0.5 to 90%.) A polyorganosiloxane represented by the formula (1) is cured by using an onium salt curing catalyst. And a pressure-sensitive adhesive member characterized by having a pressure-sensitive adhesive layer on the other surface of a supporting substrate having the above-mentioned silicone-based peelable film on one surface,
Also, the present invention provides a separator characterized in that one side of the supporting substrate has the above silicone-based peelable coating on both sides.

Action By interposing the ink affinity layer made of the film-forming resin on the side of the object to be treated, the adhesion between the peelable film and the object to be treated is improved. In addition, the oil-based ink easily penetrates, and the printability is improved.

On the other hand, the polyorganosiloxane represented by the above general formula has excellent compatibility with the onium salt-based curing catalyst based on the polyether / polymethylene component contained in the molecule,
Good and stable UV curability or thermosetting.

As a result, a silicone-based peelable film having excellent printability and peeling properties is formed.

Examples of constituent elements of the invention The silicone releasable coating of the present invention comprises a multi-layer structure of an ink affinity layer located on the side of an object to be treated and a silicone coating layer.

For forming the ink affinity layer, an easily swellable or easily soluble film-forming resin is used in an organic solvent. Swells at 25 ° C to room temperature in organic solvents, especially those used for oil-based inks,
What is soluble is preferably used. The commonly used film-forming resin includes ethyl cellulose, polyisobutylene, acrylic resin, thermoplastic polyurethane,
Examples thereof include thermoplastic polyester. Ethyl cellulose having an average content of ethoxy groups of 46 to 50% by weight per unit glucose, polyisobutylene having a weight average molecular weight of 15,000 to 2,000,000, an acrylic resin such as an acrylic resin or a methacrylic resin, or a polyethylene glycol dimethacrylate or a polyester diester. Acrylate, an acrylic resin made of a polymer of a polyfunctional acrylate such as polyurethane diacrylate, a thermoplastic polyurethane made of a linear polymer, a thermoplastic polyester made of a linear polymer having a solubility parameter of 8.9 to 11 is easily swellable, It is preferably used from the viewpoint of easy solubility.

Polyorganosiloxane represented by the following general formula is used for forming the silicone coating layer.

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

X is an epoxy functional organic group. Examples thereof include a γ-glycidyloxypropyl group: β- (3,4-epoxycyclohexyl) ethyl group: β- (4-methyl-3,4-epoxycyclohexyl) propyl group: And so on.

Y is a polyether polymethylene group. This group may be a polyether / polymethylene group-containing compound having a good compatibility with the onium salt curing catalyst. Examples include the general formula: include those represented by _{^{-R 1 -OR 2 O y R 3}} . In the formula, R ¹ is a polymethylene group. R ² is an ethylene group: [- CH ₂ CH ₂ -], propylene: _{[- CH 2 CH (CH 3)} - ] or butylene group: [- CH ₂ C
H (C ₂ H ₅₎ -] it is. R ³ is a hydrogen atom or has 1 to 2 carbon atoms
It is an alkyl group of 0. In the present invention the polymethylene group (R ¹⁾ is a trimethylene group: [- CH ₂ CH ₂ CH ₂ -] in which is preferable in view of easy availability. The degree of polymerization y of the polyether portion depends on the content ratio of the polyether / polymethylene group in the polyorganosiloxane, but generally 2 to 100 is suitable from the viewpoint of improving compatibility with the curing catalyst, and 2 to 40 is preferable. .

In the above general formula, l, m and n mean the number of contained structural units. In the present invention, m / (l + m + n) is 0.05 to 90
%, N / (l + m + n) of 0.5 to 90% is suitable. When the m / (l + m + n) is less than 0.05%, the resulting release agent has poor curability, and when it exceeds 90%, the peelable film formed has poor release performance. Also, n / (l
+ M + n) is less than 0.5%, the compatibility with the onium salt-based curing catalyst and the curability of the obtained release agent become poor.
When it exceeds%, the peelable film formed has poor peeling performance.

When imparting solvent-free coatability to the release agent, a polyorganosiloxane having a number average molecular weight of 500 to 500,000, especially 1,000 to 50,000 is preferably used.

The above-mentioned polyorganosiloxane containing an epoxy group-functional organic group and a polyether / polymethylene group in the molecule can be prepared, for example, by the following method. That is, it has a predetermined number of unsubstituted hydrogen so that the content ratio of each structural unit is as described above, and the remaining hydrogen has 1 carbon atoms.
To a polysiloxane substituted with an alkyl group, a cycloalkyl group, an aryl group or an aralkyl group of 20 and a functional group having an ethylenic double bond such as an olefin / glycidyl ether or capable of reacting with hydrogen bonded to silicon Reacting a predetermined amount of an epoxy group-containing compound with a predetermined amount of a polyether compound having an ethylenic double bond such as olefin / ethylene glycol or a functional group capable of reacting with hydrogen bonded to silicon Then, the epoxy group-containing compound and the polyether compound can be obtained by a method such as hydrosilylation via the unsubstituted hydrogen in the polysiloxane.

In the present invention, The series of structural units may be block-shaped or random.

In the present invention, the polyorganosiloxane is cured by irradiation with ultraviolet rays using an onium salt curing catalyst or by heating. The onium salt-based curing catalyst used is not particularly limited, and any known catalyst can be used.
Examples include the _{^{formula: ArN 2 + Z -, R}} 3 S + Z -, R 2 I + Z - ( provided that, Ar is an aryl group,
R is an alkyl group or an aryl group, Z ^- is _{^{BF 4 -, PF 6 -,}} AsF 6
_{^{-, SbF 6 -, SbCl 6}} -, HSO 4 -, ClO 4 - is a non-basic and non-spherical nuclei of anions such like. )
Examples thereof include diazonium salts, sulfonium salts, iodonium salts and the like.

The amount of the onium salt-based curing catalyst is appropriately 0.1 to 20 parts by weight per 100 parts by weight of polyorganosiloxane, and
5 to 10 parts by weight is preferable. If the amount is less than 0.1 part by weight, the curability is poor, and if it exceeds 20 parts by weight, the peeling performance may be hindered.

In the present invention, a monomer having one or two or more epoxy functional groups may be blended if necessary. Such a monomer is effective in dispersing the onium salt-based curing catalyst and is also effective in improving curability and printability. Examples of the commonly used monomer include ethylene glycol diglycidyl ether, glycerin diglycidyl ether, vinylcycloxene dioxide, limonene dioxide, 3,
4-epoxycyclohexylmethyl-3 ', 4'-epoxycyclohexylcarboxylate, bis- (6-methyl-3,4-epoxycyclohexyl) adipate and the like can be mentioned. The amount of the epoxy functional group-containing monomer to be compounded is suitably 10,000 to 10,000 parts by weight, preferably 10 to 1,000 parts by weight, per 100 parts by weight of polyorganosiloxane.

When a monomer having an epoxy functional group is blended, the amount of the onium salt-based curing catalyst used is appropriately 0.1 to 20 parts by weight per 100 parts by weight of the total amount of the monomer and polyorganosiloxane. Is.

Formation of the silicone-based peelable coating of the present invention, for example,
A film-forming resin dispersed or dissolved in water or an organic solvent is applied to an object to be treated and dried to form an ink affinity layer, and then a polyorganosiloxane containing an onium salt curing catalyst and the like is applied thereon. Then, a method of forming a silicone film layer by curing treatment, or a film-forming resin, polyorganosiloxane, an onium salt-based curing catalyst or the like is dispersed or dissolved in water or an organic solvent, and the liquid is applied to the object to be treated. It can be performed by a method of forming an ink affinity layer and a silicone film layer by drying, curing treatment, or the like. Also by the latter method of applying a liquid in which the respective components are mixed together, the desired silicone-based releasable film having a multi-layer structure can be formed by phase separation of the film-forming resin and polyorganosiloxane. For coating, a suitable coating machine such as a squeeze coater may be used. The curing treatment for forming the silicone coating layer can be performed by an ultraviolet irradiation method using an appropriate ultraviolet ray generator such as a high pressure mercury lamp or a metal halide lamp, a heating method, a combination method thereof, or the like.
Therefore, in the case of the above-mentioned batch mixture method, the silicone coating layer can be formed by a heat treatment which also serves to dry the coating layer, or the silicone coating layer can be formed by irradiating ultraviolet rays after drying. . The heating temperature may be appropriately determined depending on the heat resistance of the object to be treated. Generally, 60-
200 ℃, especially 100-150 ℃.

The thickness of the ink affinity layer in the silicone-based peelable film is 0.1 to 50 μm, and the thickness of the silicone film layer is 0.1 to 2 μm.
m is suitable. When the thickness of the ink affinity layer is less than 0.1 μm, the effect of improving the printability by the oil-based ink is poor.

The silicone-based releasable coating film of the present invention is preferably used for applications such as formation of a separator and rear surface treatment of an adhesive member such as an adhesive tape, which is desired to be adhered to an adhesive surface and to be easily released from the adhesive surface. .

The pressure-sensitive adhesive member of the present invention is such that such a silicone-based peelable coating is provided on one surface of a supporting substrate and an adhesive layer is attached to the other surface. Further, the separator is one in which such a silicone-based releasable coating is provided on one side or both sides of a supporting base material.
The supporting substrate used is not particularly limited. Generally,
Paper, plastic laminated paper, cloth, plastic laminated cloth, plastic film, metal foil, foam and the like are used. The pressure-sensitive adhesive member may be formed by a known method such as a method in which a pressure-sensitive adhesive is attached to the other surface of the supporting base material on which the silicone-based peelable coating is provided in advance.

EFFECT OF THE INVENTION The silicone-based peelable coating of the present invention has a multilayer structure of an ink affinity layer located on the side of the object to be treated and a silicone coating layer, and thus has excellent adhesion to the object to be treated and is hard to drop off, and oily. Ink easily penetrates and has good printability.
In addition, the silicone coating layer has excellent release properties due to its good curability.

As a result, in the pressure-sensitive adhesive member and separator of the present invention having such a silicone-based peelable coating, the peelable coating hardly contaminates the pressure-sensitive adhesive surface, and the adhesive strength is maintained good.

Example Reference Example In a glass three-necked flask equipped with a stirring blade, a thermometer, and a dropping funnel, 37.8 parts of 4-vinylcyclohexene monooxide (parts by weight, the same hereinafter) and polyethylene glycol allyl methyl ether (number average molecular weight 450) 137.1 A solution prepared by dissolving 500 parts of tetrahydrofuran in 500 parts,
After stirring for 30 minutes under a stream of dry nitrogen, 2.0 parts of platinum catalyst for hydrosilylation (platinum-vinylsiloxane complex salt) was added, and the mixture was stirred for another 10 minutes, and then the system was heated to 40 ° C.

(However, p / q = 18/10, Are arranged randomly. ) Next, 100 parts of the polydimethylmethylhydrogensiloxane copolymer having the above-mentioned molecular structure and having a number average molecular weight of 2000 is gradually added to the above system heated to 40 ° C. under stirring for about 1 hour. Then, the system was kept at 45 ° C. and reacted for 24 hours.

The obtained reaction solution is put in a vacuum dryer to dry tetrahydrofuran, and then the dried product is repeatedly purified in n-heptane to remove unreacted materials, and the n-heptane is again dried in the vacuum dryer. Removed. As a result of infrared absorption spectrum and NMR spectrum analysis, the obtained product had the following molecular structure. The number average molecular weight was 4,700.

(However, Xa Ya is _{-C 3 H 6 -OCH 2 CH 2} O 8~9 CH 3, p / r / s
= 18/5/5. Also, The array of is random. ) Example 1 When dissolved in a mixed solvent of toluene / ethanol: 80/20 (weight ratio) at a concentration of 5% by weight, the viscosity (25 ° C) was 10 cP.
s Ethyl cellulose (average content of ethoxy groups 48.0-4
(9.5% weight% / unit glucose) with methanol added 1
A 0% by weight solution was prepared, which was coated on a laminated surface of polyethylene laminated kraft paper having a thickness of 120 μm with a wire bar ROD No. 3, put in a hot air thermostat at 100 ° C. for 5 minutes and dried.

Then, on top of that, 100 parts of the polyorganosiloxane obtained in the reference example was mixed with 5 parts of a UV-reactive sulfonium salt-based curing catalyst.
The mixture prepared by adding a part of the composition is coated with a squeeze coater, and the coating surface is irradiated with 1 joule / cm ² of ultraviolet rays by an ultraviolet irradiation device equipped with a high-pressure mercury lamp for curing treatment. A separator having a film was obtained. The coating amount of the above mixture was 1 g / m ² .

Example 2 Instead of the ethyl cellulose solution, toluene was added to polyisobutylene (weight average molecular weight of about 1,000,000) and a 5% by weight solution was used. Got However,
A wire bar ROD No. 6 was used for coating.

Example 3 The silicone-based peelable coating of the present invention was prepared in the same manner as in Example 1 except that a 10 wt% emulsion of a thermoplastic polyurethane (weight average molecular weight of about 40,000) made of a linear polymer was used instead of the ethyl cellulose solution. A separator having is obtained.

Example 4 Instead of the polyisobutylene solution, a thermoplastic polyester (number average molecular weight 15,000 to 20,000, softening point 163 ° C., solubility parameter 10.1) was added to toluene / methyl ethyl ketone: 80 /
A separator having a silicone-based releasable coating of the present invention was obtained in the same manner as in Example 2 except that a 5% by weight solution prepared by adding a mixed solvent of 20 (weight ratio) was used.

Example 5 Instead of the polyisobutylene solution, an acrylic resin (butyl acrylate / methyl methacrylate / acrylic acid 2-
Hydroxyethyl: 10/85/5 (weight ratio), weight average molecular weight about 500,000) Implemented except using a 5% by weight solution prepared by adding a mixed solvent of toluene / methanol: 90/10 (weight ratio) A separator having the silicone-based releasable coating of the present invention was obtained in the same manner as in Example 2.

Example 6 Thermoplastic Polyester Used in Example 4 / Polyorganosiloxane Obtained in Reference Example / Thermal-Reactive Sulfonium Salt Curing Catalyst: 30/66/4 (Weight Ratio) to Toluene / Methyl Ethyl Ketone: 80/20 (Weight) Ratio) to prepare a 10 wt% solution, which is then wire bar ROD No. 6
Coat the laminated surface of polyethylene laminated kraft paper with a thickness of 120 μm so that the coating amount will be 1 g / m ^2, and then 100 ℃
Put in a hot air thermostat for 10 minutes and dry and cure,
A separator having the silicone-based peelable coating of the present invention was obtained.

Comparative Example 1 A separator having a silicone-based releasable coating was obtained in the same manner as in Example 1 except that the silicone coating layer was directly provided on the laminated surface of polyethylene laminated kraft paper without providing the ink affinity layer made of the ethylcellulose solution.

Comparative Example 2 In Example 1 except that a polyorganosiloxane having an epoxy functional organic group but no polyether / polymethylene group was prepared according to the reference example without using polyethylene glycol allyl methyl ether. Accordingly, a separator having a silicone-based peelable coating was obtained.

Evaluation Test The following characteristics of the separators obtained in Examples and Comparative Examples were examined.

[Curability] The case where the peelable film on the separator did not have stickiness was evaluated as ◯, the case where there was a little stickiness was evaluated as Δ, and the case where stickiness was large was evaluated as x.

[Printability] Characters were written on the surface of the peelable film of the separator with a commercially available oil-based ink pen, and when there was no cissing, it was evaluated as ⊚, when there was almost no repelling, as ○, when there was a little repelling, and when marked.

[Peeling force] A commercially available adhesive tape with a width of 25 mm (craft tape No712, manufactured by Nitto Denko Corporation) was reciprocated with a 2 kg comb roller on the peelable film surface of the separator under 20 ° C and 65% R, H. After pressure-bonding, apply a load of 50 g / cm ² on the adhesive tape and leave it at 20 ° C for 48 hours. Then, the load is released and the product is left for 2 hours at 20 ° C and 65% R, H, and the resulting tape is peeled off with a shopper at a speed of 300 mm / min (180 degree peeling). Was calculated (average value of 4 samples).

[Residual adhesion rate] (Non-staining of the pressure-sensitive adhesive surface) The pressure-sensitive adhesive tape after measuring the above-mentioned peeling force
Water resistant abrasive paper (No. 280) of stainless steel plate (SUS27CP) under H
After sufficiently polishing it, a rubber roller having a weight of 2 kg was reciprocated once on the washed surface and pressure-bonded, and the force required for peeling was determined in the same manner as above for the one left for 30 minutes.
Then, the ratio of the residual adhesive force of the obtained measured value to the measured value obtained for the adhesive tape that had not been brought into contact with the peelable film surface in the same manner as above was calculated as the residual adhesive rate (average of 4 samples). value).

 The results are shown in the table.

As is apparent from the table, the silicone-based releasable coating film of the present invention is excellent in curability, oil-based ink printability, and non-staining property of the adhesive surface.

Claims (3)

(57) [Claims] 1. A silicone film layer is formed on an ink-affinity layer made of a film-forming resin that is easily swellable or soluble in an organic solvent, and the silicone film layer has a general formula. (However, 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 / ( (1 + m + n) is 0.05 to 90%, and n / (l + m + n) is 0.5 to 90%.) is a polyorganosiloxane represented by curing treatment using an onium salt curing catalyst. A silicone-based peelable coating characterized by. 2. An adhesive member having an adhesive layer on the other surface of a supporting substrate having the silicone-based releasable film according to claim 1 on one surface. 3. A separator comprising the supporting base material and the silicone-based releasable coating according to claim 1 on one or both sides.