Release agent for silicone based adhesive and use method therefor

Abstract

To provide a release agent for silicone-based adhesive and a use method therefor that facilitate separating a rubber sheet and eliminate remaining adhesive removal work, irrespective of a surface temperature of an adherend.SOLUTION: A release agent 20 for silicone-based adhesive that is used for releasing a silicone-based adhesive layer of a rubber sheet 10 adhering to an adherend 1, and contains a siloxane material containing a plurality of Si-H. The amount of the release agent is 12 g or greater, the concentration of the release agent is 20 wt% or more and 100 wt% or less, the viscosity at 25°C is 2.0 mm2 / s or greater, the specific gravity at 25°C is 0.9 or greater, and the functional group equivalent is 0.0038 g / mol or greater. Since an excessive viny group estimated to remain in the adhesive portion of a silicone gel 12 is cross-linked in a short time by the release agent 20 for silicone-based adhesive, the viscosity of the adhesive portion of the silicone gel 12 can be reduced.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a release agent for silicone-based pressure-sensitive adhesives, which is used to remove the silicone-based pressure-sensitive adhesive layer of a rubber sheet adhered to an adherend such as a steel pipe-containing structure, bridge, or drainage ditch, and to a method for using the same. [Background technology]

[0002] Conventionally, silicone rubber sheets that provide waterproofing and corrosion protection have been adhered to adherends such as steel pipe structures, bridges, and drainage ditches, but the adhered rubber sheets are generally removed by physical force (not shown). Specifically, the rubber sheet is generally removed by inserting a spatula between the adherend and the silicone gel of the rubber sheet and manually pulling up the rubber sheet (see Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2001-519237 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-018837 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventional rubber sheets are peeled off by physical force as described above, but when the surface temperature of the adherend is high, there are problems such as difficulty in peeling and the need to remove the remaining adhesive. To explain this point in more detail, the silicone gel that forms the rubber sheet has the characteristic that the higher the surface temperature of the adherend, the more viscous it becomes than elastic.

[0005] For example, when the adherend is a steel pipe in a structure that is exposed to sunlight for long periods of time, the viscosity of the silicone gel will be greater than the elasticity of the silicone gel. As a result, when the rubber sheet is peeled off from the adherend, the viscosity of the silicone gel will be greater, causing the adhesive in the silicone gel to stretch, resulting in the problem of making it difficult to peel the rubber sheet. Furthermore, the amount of silicone gel adhesive remaining on the adherend (residue) will increase, making it essential to remove the adhesive remaining on the adherend.

[0006] The present invention has been made in view of the above, and aims to provide a release agent for silicone-based pressure-sensitive adhesives that facilitates the release of rubber sheets regardless of the surface temperature of the adherend, and that eliminates the need for the work of removing residual pressure-sensitive adhesive, as well as a method for using the same. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention provides a release agent for silicone-based adhesives used to remove the silicone-based adhesive layer of a rubber sheet adhered to an adherend, which is characterized by containing a substance containing multiple Si-H groups.

[0008] The amount of release agent is 12 g or more, the release agent concentration is 20 wt% or more and 100 wt% or less, and the viscosity at 25°C is 2.0 mm 2 It is preferable that the specific gravity at 25°C is 0.9 or more and the functional group equivalent is 0.0038 g / mol or more. In addition, it contains 12g or more of low viscosity dilution oil, and the viscosity of this dilution oil at 25℃ is 0.60mm 2 / s or more, and a specific gravity at 25°C of 0.7 or more.

[0009] In order to solve the above problems, the present invention also provides a method for using a release agent for silicone pressure-sensitive adhesives, which comprises applying the release agent for silicone pressure-sensitive adhesives according to claim 1 or 2 to a rubber sheet adhered to an adherend, and peeling off the silicone pressure-sensitive adhesive layer from the rubber sheet, comprising: The rubber sheet is characterized by its peeling force being 0.7N / 20mm or more and 7.7N / 20mm or less when measured in accordance with JIS Z0237 when it is pulled up and peeled off.

[0010] Here, the term "adherend" in the claims includes at least structures containing steel pipes, bridge joints, tunnels, drainage ditches, water tanks, roof leaks, pet marking areas on pedestrian bridges, and various poles and supports such as utility poles. The up / down, front / back, left / right directions of the adherend are based on the drawings and can be appropriately changed as needed. Furthermore, the rubber sheet preferably includes a flexible silicone rubber sheet and a silicone-based adhesive layer laminated on the silicone rubber sheet and capable of adhering to the adherend. Each numerical value may include measurement error as well as different values, provided that there is no difference in the effects of the present invention. Furthermore, dilution oil can be omitted if it is not necessary.

[0011] According to the present invention, excess vinyl groups presumably remaining in the adhesive portion of the silicone adhesive layer of the rubber sheet are crosslinked by the release agent for silicone adhesives, thereby reducing the viscosity of the adhesive portion of the silicone adhesive layer. This reduced viscosity increases elasticity, so that even when the surface temperature of the adherend is high, the rubber sheet can be peeled off in a shorter time than before, and the work of removing the adhesive remaining on the adherend can be reduced. [Effects of the Invention]

[0012] According to the present invention, since the adhesive contains a substance having multiple Si-H groups, the rubber sheet can be easily peeled off regardless of the surface temperature of the adherend, and further, the work of removing remaining adhesive can be omitted.

[0013] According to the invention described in claim 2, the amount of the stripping agent is 12 g or more, the stripping agent concentration is 20 wt% or more and 100 wt% or less, and the viscosity at 25°C is 2.0 mm 2 / s or more, specific gravity at 25°C of 0.9 or more, and functional group equivalent of 0.0038 g / mol or more, so excess vinyl groups remaining in the adhesive residue of the silicone adhesive layer can be crosslinked in a short period of time. According to the invention of claim 3, since the low-viscosity diluent oil is contained in an amount of 12 g or more, it is expected that the penetration of the release agent for silicone adhesives into the silicone adhesive layer will be promoted. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a cross-sectional view schematically illustrating an embodiment of a release agent for silicone-based pressure-sensitive adhesives and a method of using the same according to the present invention. [Figure 2] 1 is a cross-sectional view schematically illustrating a rubber sheet in an embodiment of the release agent for silicone-based pressure-sensitive adhesives and the method of using the same according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] A preferred embodiment of the present invention will now be described with reference to the drawings. As shown in FIG. 1, the release agent 20 for silicone adhesives in this embodiment is a liquid release agent used to remove a rubber sheet 10 adhered to an adherend 1. By containing a siloxane material containing multiple relatively low molecular weight Si—H groups, the release agent contributes to the achievement of Goal 9 of the SDGs adopted at the United Nations Summit.

[0016] The adherend 1 is not particularly limited, but examples thereof include steel pipes for structures, specifically, road sign posts erected on the side of roads, and concrete components of bridges.

[0017] As shown in Figure 2, rubber sheet 10 is a flat silicone-based adhesive rubber sheet with a three-layer structure comprising a silicone rubber sheet 11 that is affected by sunlight, wind and rain, a silicone gel 12 that is laminated directly on one side of silicone rubber sheet 11 and can adhere to adherend 1, and a bendable separator 13 that is releasably laminated on silicone gel 12.

[0018] Silicone rubber sheet 11 is molded into a flexible, bendable gray or transparent sheet, and exhibits excellent cold resistance, durability, weather resistance, waterproofness, lubricity, non-corrosion, processability, workability, and environmental friendliness. From the viewpoint of improving formability and workability, the thickness of silicone rubber sheet 11, as measured with a predetermined measuring device, is preferably 0.4 mm to 1.5 mm, more preferably 0.5 mm to 1.5 mm, and even more preferably 0.8 mm to 1.5 mm.

[0019] The physical properties of the silicone rubber sheet 11 are as follows: a durometer A hardness of 50 or more and 80 or less, preferably 55 or more and 75 or less; a tear strength of 8 kN / m or more and 300 kN / m or less, preferably 20 kN / m or more and 280 kN / m or less, when measured in accordance with JIS K6253; a breakdown voltage of 20 kV or more, preferably 30 kV or more, when measured in accordance with JIS K6249; and a tensile strength of 5 MPa or more, preferably 5 MPa or more and 80 MPa or less, more preferably 8 MPa or more and 75 MPa or less, when measured in accordance with JIS K6253.

[0020] The silicone gel 12 is formed as a gel-like sheet that has excellent affinity and adhesive properties with the silicone rubber sheet 11. It adheres tightly to one side of the silicone rubber sheet 11, firmly adhering to the surface of the adherend 1. The thickness of the silicone gel 12 is preferably 1.0 mm to 2.0 mm, and more preferably 1.0 mm to 1.5 mm, to ensure excellent conformability when measured with a specific measuring device. The reason why the thickness of the silicone gel 12 is 1.0 mm or more is that a thickness of less than 1.0 mm can result in a decrease in adhesive function, depending on the material. Furthermore, the hardness of the silicone gel 12, as measured with an Asker CSR2, is preferably 20 or less, more preferably 18 or less, and even more preferably 15 or less.

[0021] As shown in the figure, separator 13 is made of, for example, an inexpensive polyethylene resin film that is easy to process, flexible, and versatile, and is laminated on the exposed surface of silicone gel 12 until rubber sheet 10 is used to ensure the adhesive strength of silicone gel 12. This separator 13 is preferably fluorine-treated to prevent contamination. The thickness of separator 13 is not particularly limited, but is optimally, for example, between 30 μm and 500 μm, preferably between 30 μm and 100 μm, and more preferably between 30 μm and 50 μm, as measured with a specified measuring device.

[0022] Such rubber sheet 10 is not particularly limited, but examples thereof include Shin-Etsu Patch Seal Series (product name manufactured by Shin-Etsu Chemical Co., Ltd.), Shin-Etsu Patch Seal Toumei (product name manufactured by Shin-Etsu Chemical Co., Ltd.), and Shin-Etsu Patch Seal Cross (product name manufactured by Shin-Etsu Chemical Co., Ltd.).

[0023] The release agent 20 for silicone-based pressure-sensitive adhesives is prepared by containing a release agent that releases the silicone gel 12 from the rubber sheet 10, and a low-molecular-weight diluent oil that is added to the release agent as needed. The release agent contains a siloxane material, such as silicone oil, which is a linear polymer consisting of siloxane bonds, and in order to crosslink excess vinyl groups that are presumed to remain in the remaining adhesive of the silicone gel 12 in a short period of time and to facilitate workability and handling, the amount of release agent is 12 g or more, preferably 12 g to 55 g, more preferably 12.5 g to 50.0 g, and the release agent concentration is 20 wt% to 100 wt%, preferably 25 wt% to 100 wt%.

[0024] In addition, the viscosity at 25°C is 2.0 mm 2 / s or more, preferably 2.0 mm 2 / s or more 20.05mm 2 / s or less, preferably 2.3 mm 2 / s or more 20.0mm 2The viscosity is preferably 0.9 / s or less, the specific gravity at 25°C is 0.9 or more, preferably 0.9 to 1.02, more preferably 0.91 to 1.00, and the functional group equivalent is preferably 0.0038 g / mol or more, preferably 0.0038 g / mol to 62.0 g / mol, more preferably 0.0040 g / mol to 60.0 g / mol. The functional group equivalent is 0.0038 g / mol or more because if it is 0.0038 g / mol or more, two or more low-molecular-weight Si—H groups can be contained.

[0025] Such a release agent is not particularly limited, but examples thereof include hydrogen silicone oil KF-99 (product name, manufactured by Shin-Etsu Chemical Co., Ltd.) and 1,1,3,3,5,5,7,7,9,9,11,11,13,13-tetradecamethylheptasiloxane (product name, manufactured by Tokyo Chemical Industry Co., Ltd.).

[0026] The dilution oil is, for example, dimethyl silicone oil, and the amount of oil is 12 g or more, preferably 12 g or more and 38 g or less, more preferably 12.5 g or more and 37.5 g or less, and the viscosity at 25°C is 0.60 mm 2 / s or more, preferably 0.60 mm 2 / s or more 21.0mm 2 / s or less, preferably 0.65 mm 2 / s or more 20.0mm 2 / s or less, and the specific gravity at 25°C is 0.7 to 1.00, preferably 0.76 to 0.95. 2 / s or more 21.0mm 2 / s or less because a low viscosity in this range is expected to promote penetration into the silicone gel 12.

[0027] Suitable dilution oils include, for example, KF-96L-0.65cs (product name, manufactured by Shin-Etsu Chemical Co., Ltd.) and KF-96L-20cs (product name, manufactured by Shin-Etsu Chemical Co., Ltd.).

[0028] In the above configuration, when removing the rubber sheet 10 adhered to the adherend 1, first, a low-viscosity silicone adhesive release agent 20 is applied to the rubber sheet 10 by spraying or brushing. When applying the relatively low-viscosity silicone adhesive release agent 20 to the rubber sheet 10, it may be applied to the surface of the silicone rubber sheet 11 or to the boundary between the surface of the adherend 1 and the silicone gel 12. The applied relatively low-viscosity silicone adhesive release agent 20 reaches and penetrates into the silicone gel 12 of the rubber sheet 10, causing crosslinking to proceed.

[0029] After applying the silicone adhesive release agent 20, the silicone adhesive release agent 20 is left to stand under atmospheric pressure for a predetermined time, the rubber sheet 10 is gradually pulled up from the edge and peeled off, and then the adhesive surface of the rubber sheet 10 on the adherend 1 is simply cleaned with alcohol or the like, completing the peeling process of the rubber sheet 10 adhered to the adherend 1. The time for leaving it under atmospheric pressure is not particularly limited, but is preferably at least 30 minutes, preferably at least 1 hour, more preferably at least 3 hours, and even more preferably at least 5 hours.

[0030] From the viewpoint of achieving smooth peeling in a short time, the peeling force when pulling up and peeling off the rubber sheet 10 is optimally 0.7 N / 20 mm or more and 7.8 N / 20 mm or less, preferably 0.8 N / 20 mm or more and 7.6 N / 20 mm or less, and more preferably 0.9 N / 20 mm or more and 7.5 N / 20 mm or less, when measured in accordance with JIS Z0237:2009.

[0031] As described above, excess vinyl groups presumably remaining in the adhesive portion of silicone gel 12 are crosslinked in a short time by silicone adhesive release agent 20, thereby reducing the viscosity of the adhesive portion of silicone gel 12. This reduction in viscosity increases elasticity, making it easy to peel rubber sheet 10 smoothly and quickly even when the surface temperature of adherend 1 is high, and the step of removing adhesive remaining on adherend 1 can also be omitted.

[0032] Furthermore, when the silicone-based adhesive release agent 20 contains a diluent oil with an extremely low molecular weight, the diluent oil volatilizes over time. Therefore, when the rubber sheet 10 is peeled off and cleaned up, the adherend 1 and the rubber sheet 10 do not become slimy, making cleanup and cleanup easier. Furthermore, by appropriately changing the molecular weight and amount of the diluent oil, it is possible to adjust the time until the rubber sheet 10 can be peeled off.

[0033] The silicone rubber sheet 11 in the above embodiment may incorporate a reinforcing member such as glass cloth. Furthermore, various resin films or sheets other than polyethylene resin films may be used for the separator 13, as needed. After applying the silicone pressure-sensitive adhesive release agent 20, heat may be applied to the rubber sheet 10 at a predetermined temperature using an iron or steam, etc., to peel the rubber sheet 10 in a short period of time. Furthermore, all of the technologies described in this specification may be subject to patent protection through amendments, divisional applications, etc. [Example]

[0034] Examples of the release agent for silicone-based pressure-sensitive adhesives according to the present invention and its method of use will be described below together with comparative examples. [Preparation of test specimens] First, a three-layer rubber sheet as shown in Figure 2 was prepared and processed to produce multiple test specimens. The rubber sheet was a Shin-Etsu Patch Seal Toumei HNS-200T (product name, manufactured by Shin-Etsu Chemical Co., Ltd.). Each test specimen measured 20 mm x 320 mm. After producing multiple test specimens in this manner, the separators of two test specimens were peeled off to expose the silicone gel, and the two test specimens were placed on a steel plate so that the lower silicone gel layer came into contact with the surface of the steel plate. The steel plate was a hot-dip galvanized type, measuring 60 mm x 145 mm.

[0035] After placing the two test pieces on the steel plate, a manual pressure roller conforming to JIS Z0237 (Imada Co., Ltd.: APR-97-2K) was placed on the silicone rubber sheet of each test piece, and this manual pressure roller was run back and forth at as constant a speed as possible to press the test piece onto the surface of the steel plate via the silicone gel.The two test pieces were then left to stand at atmospheric pressure in an environment of approximately 25°C for approximately one month.

[0036] Example 1 First, a predetermined amount of silicone adhesive release agent was prepared in a plastic cup. Specifically, 50 g of KF-99 (product name, manufactured by Shin-Etsu Chemical Co., Ltd.) was prepared as the silicone adhesive release agent, but no diluting oil was used (see Tables 1 and 2).

[0037] Next, 0.5 ml per sample of silicone adhesive release agent was dropped onto the silicone rubber sheet of each test piece using a disposable dropper, and then each test piece was left to stand at atmospheric pressure for 5 hours at 25°C. The reason for using 0.5 ml per sample is that this amount would ensure that the silicone adhesive release agent would not drip from the test piece.

[0038] The adhesive strength of each test piece was then measured in accordance with JIS Z0237:2009 using a tensile tester (Shimadzu Corporation: product name AG-20kN Xplus). Measurements were performed under conditions of a load cell of 1 kN and a tensile speed of 300 mm / min. After measuring the adhesive strength in this way, the adhesive strength over 100 mm of each test piece, excluding 10 mm at both ends, was averaged to determine the peel strength, which is listed in Table 3.

[0039] Example 2 First, a predetermined amount of silicone adhesive release agent was prepared in a plastic cup. Specifically, 37.5 g of KF-99 (product name, manufactured by Shin-Etsu Chemical Co., Ltd.) was added as the release agent for silicone adhesive release agents, and 12.5 g of KF-96L-0.65cs (product name, manufactured by Shin-Etsu Chemical Co., Ltd.) was added as diluent oil for the silicone adhesive release agent, and these were blended to prepare the silicone adhesive release agent (see Tables 1 and 2).

[0040] Next, 0.5 ml per sample of silicone adhesive release agent was dropped onto the silicone rubber sheet of each test piece using a disposable dropper, and then each test piece was left to stand at atmospheric pressure for 5 hours at 25°C. The reason for using 0.5 ml per sample is that this amount would ensure that the silicone adhesive release agent would not drip from the test piece.

[0041] The adhesive strength of each test piece was then measured in accordance with JIS Z0237:2009 using a tensile tester (Shimadzu Corporation: product name AG-20kN Xplus). Measurements were performed under conditions of a load cell of 1 kN and a tensile speed of 300 mm / min. After measuring the adhesive strength in this way, the adhesive strength over 100 mm of each test piece, excluding 10 mm at both ends, was averaged to determine the peel strength, which is listed in Table 3.

[0042] Example 3 The procedure was basically the same as in Example 2, except that 25.0 g of KF-99 (product name, manufactured by Shin-Etsu Chemical Co., Ltd.) was added as a release agent for the silicone adhesive release agent, and 25.0 g of KF-96L-0.65cs (product name, manufactured by Shin-Etsu Chemical Co., Ltd.) was added as a dilution oil for the silicone adhesive release agent, and these were blended to prepare a release agent for silicone adhesives (see Tables 1 and 2).

[0043] Example 4 The procedure was basically the same as in Example 2, except that 12.5 g of KF-99 (product name, manufactured by Shin-Etsu Chemical Co., Ltd.) was added as a release agent for the silicone adhesive release agent, and 37.5 g of KF-96L-0.65cs (product name, manufactured by Shin-Etsu Chemical Co., Ltd.) was added as a dilution oil for the silicone adhesive release agent, and these were blended to prepare a release agent for silicone adhesives (see Tables 1 and 2).

[0044] Example 5 The procedure was basically the same as in Example 2, but 25.0 g of KF-99 (product name, manufactured by Shin-Etsu Chemical Co., Ltd.) was added as a release agent for the silicone adhesive release agent, and 25.0 g of KF-96-20cs (product name, manufactured by Shin-Etsu Chemical Co., Ltd.) was added as a dilution oil for the silicone adhesive release agent, and these were blended to prepare a release agent for silicone adhesives (see Tables 1 and 2).

[0045] Example 6 The procedure was basically the same as in Example 5, except that 12.5 g of KF-99 (product name, manufactured by Shin-Etsu Chemical Co., Ltd.) was added as a release agent for the silicone adhesive release agent, and 37.5 g of KF-96-20cs (product name, manufactured by Shin-Etsu Chemical Co., Ltd.) was added as a dilution oil for the silicone adhesive release agent, and these were blended to prepare a release agent for silicone adhesives (see Tables 1 and 2).

[0046] Example 7 The procedure was basically the same as in Example 1, except that a predetermined amount of a release agent for silicone-based pressure-sensitive adhesives was placed in a plastic cup. Specifically, 50 g of T3548 (product name, manufactured by Tokyo Chemical Industry Co., Ltd.) was placed as the release agent for silicone-based pressure-sensitive adhesives, and no diluent oil was used (see Tables 1 and 2).

[0047] Comparative Example 1 Without dripping any silicone adhesive release agent onto the silicone rubber sheet of each test piece (see Tables 1 and 2), the adhesive strength of each test piece was measured in accordance with JIS Z0237:2009 using a tensile tester (Shimadzu Corporation: product name AG-20kN Xplus). Measurements were carried out under conditions of a load cell of 1 kN and a tensile speed of 300 mm / min. After measuring the adhesive strength in this way, the adhesive strength over a 100 mm area of ​​each test piece, excluding 10 mm at both ends, was averaged to determine the peel strength, which is listed in Table 3.

[0048] Comparative Example 2 The procedure was basically the same as in Example 1, except that a predetermined amount of a release agent for silicone-based pressure-sensitive adhesives was prepared in a plastic cup. Specifically, 50 g of T1267 (product name, manufactured by Tokyo Chemical Industry Co., Ltd.) was placed in the cup as the release agent for silicone-based pressure-sensitive adhesives, and no diluting oil was used.

[0049] [Table 1]

[0050] [Table 2]

[0051] [Table 3]

[0052] [Table 4]

[0053] 〔evaluation〕 In each example, the peeling force required to peel the test piece was reduced, allowing the test piece to be easily peeled off in a short time. In particular, in examples 1 to 3, the adhesive strength was reduced to 1 / 9 of that of comparative example 1, allowing extremely easy manual peeling. Furthermore, as shown in Table 4, no adhesive remained on the surface of the steel sheet, making it possible to omit the adhesive removal process.

[0054] In contrast, in Comparative Example 1, no silicone-based adhesive release agent was used, so the peel force required to peel the test piece could not be reduced, making it difficult to peel the test piece in a short time. Furthermore, as shown in Table 4, a large amount of adhesive remained on the surface of the steel plate, so the adhesive had to be removed. In the case of Comparative Example 2, the viscosity of the release agent at 25°C was 2.0 mm 2Because the tensile strength was less than 1 / s and the specific gravity at 25°C was less than 0.9, the peel force required to peel the test piece could not be reduced, making it very difficult to peel the test piece. Furthermore, as shown in Table 4, a large amount of adhesive remained on the surface of the steel sheet, requiring the adhesive to be removed. [Industrial Applicability]

[0055] The release agent for silicone pressure sensitive adhesives and the method for using the same according to the present invention are used in fields such as construction and civil engineering that use rubber sheets. [Explanation of symbols]

[0056] 1 Adherent 10 rubber sheet 11 Silicone rubber sheet 12 Silicone gel (silicone adhesive layer) 13 Separator 20. Release agents for silicone adhesives

Claims

1. A release agent for silicone-based pressure-sensitive adhesives used to remove a silicone-based pressure-sensitive adhesive layer from a rubber sheet adhered to an adherend, comprising: A release agent for silicone-based pressure-sensitive adhesives, characterized by containing a substance containing multiple Si-H groups.

2. The amount of release agent is 12 g or more, the release agent concentration is 20 wt% or more and 100 wt% or less, and the viscosity at 25°C is 2.0 mm ２ 2. The release agent for silicone pressure-sensitive adhesives according to claim 1, having a viscosity of at least 1000 s / s, a specific gravity at 25°C of at least 0.9, and a functional group equivalent of at least 0.0038 g / mol.

3. The dilution oil contains 12 g or more of low viscosity dilution oil, and the viscosity of the dilution oil at 25°C is 0.60 mm ２ 3. The release agent for silicone pressure-sensitive adhesives according to claim 1, wherein the release agent has a viscosity of 1 / s or more and a specific gravity at 25°C of 0.7 or more.

4. 1. A method for using a release agent for silicone pressure-sensitive adhesives, comprising applying the release agent for silicone pressure-sensitive adhesives according to claim 1 or 2 to a rubber sheet adhered to an adherend, and peeling off the silicone pressure-sensitive adhesive layer from the rubber sheet, comprising: A method for using a release agent for silicone-based pressure-sensitive adhesives, characterized in that the peel force when peeling off a rubber sheet by lifting it up is 0.7 N / 20 mm or more and 7.8 N / 20 mm or less when measured in accordance with JIS Z0237.

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