JP4451710B2 - Peeling substrate and method for producing the same, adhesive sheet and adhesive tape - Google Patents

Description

  The present invention relates to a peelable substrate used for pressure-sensitive adhesive labels, pressure-sensitive adhesive tapes, and the like, and in particular, to a releasable peelable substrate having no film such as polyethylene and a method for producing the same. Furthermore, it is related with the manufacturing method of an adhesive sheet and an adhesive tape.

  Release materials used for pressure-sensitive adhesive sheets and substrates used for pressure-sensitive adhesive tapes (hereinafter collectively referred to as release substrates) are obtained by applying a release agent such as silicone on a base paper. In the release substrate, it is necessary to provide a release agent layer uniformly in order to enhance the release characteristics. For this reason, as the base paper of the release substrate, one that does not easily penetrate the release agent during application is used. It was. For example, as a base paper, a laminated paper laminated with a film of polyethylene or the like, or a glassine paper that has been subjected to a smoothing treatment after impregnating a large amount of an adhesive with a pulp fiber highly beaten as a main raw material. Such densified base paper has been widely used. In addition, undercoat paper in which a barrier coating solution made of starch, polyvinyl alcohol, latex, pigment, or the like is applied to a paper base material to provide a sealing layer has also been used.

However, in the case of laminated paper, lamination with an extruded film using a T-die is necessary. In the case of high-density base paper, smoothing processing is required by equipment such as papermaking and supercalender. In the case of undercoated paper, An application process of a barrier coating solution was necessary. Accordingly, release substrates using these base papers are expensive because they have many steps in production.
Furthermore, a laminate film with a thickness of 10 to 20 μm is firmly adhered to the paper in the laminated paper, and a high density base paper contains a large amount of adhesive and is highly densified. It also has the disadvantage that it is soluble and cannot be easily recycled. Therefore, the actual condition is that the release substrate is finally incinerated, which is a big problem from the viewpoint of resource saving and environmental protection in recent years.

For the purpose of solving the above problems, a release agent composition comprising a silicone emulsion and polyvinyl alcohol is directly applied to a paper substrate (see Patent Documents 1 and 2), a silicone emulsion or a silicone emulsion and a viscosity modifier, Directly applying a release agent composition comprising a paper base material (see Patent Document 3), and directly applying a release agent composition comprising a silicone emulsion having an average particle size of 200 nm or less and a water-soluble resin to a paper base material. (See Patent Document 4) and the like have been proposed.
In any of the techniques described in Patent Documents 1 to 4, since the release agent is directly applied to the paper base material, the manufacturing process can be simplified and the recycling can be performed. In addition, since the silicone emulsion is water-based, the environmental load due to the use of a solvent can be reduced.
Japanese Patent Laid-Open No. 3-287683 JP-A-4-130173 JP-A-6-248244 JP 2003-147893 A

However, when the release substrate is obtained by the method described in Patent Document 1 or Patent Document 2, the drying load of the release agent is large and the productivity is lowered. There was a problem that the peeling force was extremely heavy.
Moreover, in the peeling base material obtained by the method of patent document 3, the water resistance and solvent resistance of the release agent layer were low, and the barrier property was inferior. Therefore, for example, when a solvent-based pressure-sensitive adhesive is applied on the release agent layer to form a pressure-sensitive adhesive sheet, there arises a problem that the peeling force is extremely heavy.
Furthermore, in the method described in Patent Document 4, the stability of the release agent paint decreases with time, and in the formulation examples shown in the Examples of Patent Document 4, the number of silicone parts is too small. When the pressure-sensitive adhesive sheet was obtained, there was a problem that the peeling force was extremely heavy.
The present invention has been made in view of the above circumstances. In addition to being able to use a release agent coating excellent in stability over time, it has a release agent layer having high barrier properties and high release characteristics, and is also recyclable. An object is to provide an excellent release substrate and a method for producing a release substrate from which the release substrate can be easily obtained. Furthermore, it aims at providing an adhesive sheet and an adhesive tape.

The release substrate of the present invention is a release substrate in which a release coating containing a silicone emulsion and a water-soluble resin is applied to a paper substrate.
The silicone emulsion consists of (I) 100 parts by mass of an organopolysiloxane having two or more alkenyl groups in one molecule, and (II) an organohydrogen poly having at least one hydrogen atom directly bonded to a silicon atom in one molecule. 1-30 mass parts of siloxane is what was emulsified with the surfactant for emulsification which contains 70 mass% or more of polyvinyl alcohol, It is characterized by the above-mentioned.
The first release substrate production method of the present invention comprises a coating step of applying a release agent paint containing a silicone emulsion and a water-soluble resin on at least one side of a paper substrate, and a coating film of the release agent paint after the application step. A method for producing a release substrate having a drying step of preliminary drying at less than 100 ° C. and then main drying at 100 ° C. or more,
As a silicone emulsion, (I) 100 parts by mass of an organopolysiloxane having two or more alkenyl groups in one molecule and (II) an organohydrogen poly having at least one hydrogen atom directly bonded to a silicon atom in one molecule 1-30 mass parts of siloxane is used what was emulsified with the surfactant for emulsification containing 70 mass% or more of polyvinyl alcohol.
The manufacturing method of the 2nd peeling base material of this invention is the application process which apply | coats the release agent coating material containing a silicone emulsion and a water-soluble resin on the single side | surface of a paper base material, and after 3 second or more passes since completion | finish of an application process, A method for producing a release substrate having a drying step of subjecting the paint film of the release agent paint to a main drying at 100 ° C. or more,
As a silicone emulsion, (I) 100 parts by mass of an organopolysiloxane having two or more alkenyl groups in one molecule and (II) an organohydrogen poly having at least one hydrogen atom directly bonded to a silicon atom in one molecule 1-30 mass parts of siloxane is used what was emulsified with the surfactant for emulsification containing 70 mass% or more of polyvinyl alcohol.
The pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet having a support, a pressure-sensitive adhesive layer sequentially provided on at least one surface of the support, and a release substrate, and the release substrate is the release substrate described above. It is characterized by being.
The pressure-sensitive adhesive tape of the present invention is a pressure-sensitive adhesive tape having a peeling base material on which one side is peeled off and a pressure-sensitive adhesive layer provided on the other side of the peeling base material. It is characterized by being a release substrate.

  According to the present invention, it is possible to use a release agent coating having excellent stability over time, and to easily obtain a release substrate having a release agent layer having high barrier properties and high release characteristics and excellent in recyclability. be able to.

The manufacturing method of the peeling base material of this invention is demonstrated.
<Peeling substrate>
The release substrate in the present invention is one in which a release agent paint containing a silicone emulsion and a water-soluble resin is applied to a paper substrate, and a release agent layer which is a coating film of the release agent paint is provided.

[Paper base]
Examples of the paper substrate used in the present invention include high-quality paper / medium-quality paper mainly composed of wood pulp, and finely coated paper, coated paper, art paper, etc., in which a paint mainly composed of pigment is applied. Coated paper, kraft stretched paper, and kraft paper can be used. The paper base material has a certain degree of air permeability and water absorption, but it is preferable that the air permeability and water absorption are low from the viewpoint of suppressing penetration of the release agent paint. Specifically, the air permeability is determined according to J.J. TAPPI No. 5-2: It is preferable that the air permeability is 10 seconds or more when expressed by the Oken air permeability according to 2000. Moreover, when the water absorption is expressed by the Cobb water absorption in accordance with JIS P8140, the water absorption is preferably 30 g / m ² or less. Further, in order to enable uniform application of the release agent paint, smoothness is set to J.R. TAPPI No. 5-2: When expressed by Oken smoothness based on 2000, the smoothness is preferably 50 seconds or more.

[Release paint]
The silicone emulsion contained in the release coating is composed of (I) 100 parts by mass of an organopolysiloxane having two or more alkenyl groups in one molecule, and (II) at least one hydrogen atom directly bonded to a silicon atom in one molecule. One to 30 parts by mass of an organohydrogenpolysiloxane is emulsified with a surfactant for emulsification. Organopolysiloxane and organohydrogenpolysiloxane are sometimes collectively referred to as silicone components.
(I) As organopolysiloxane, the following compound (A) can be illustrated. Examples of (II) organohydrogenpolysiloxane include the following compound (B).

（ｍは整数を示す）

(M represents an integer)

（Ｒ^１は水素またはアルキル基、ｎは整数を示す）

(R ¹ represents hydrogen or an alkyl group, and n represents an integer)

 The emulsifying surfactant used for emulsifying the silicone component includes polyvinyl alcohol, and the amount of polyvinyl alcohol in the total emulsifying surfactant is 70% by mass or more. When the surfactant for emulsification of the silicone emulsion contains a specific amount of polyvinyl alcohol, it has excellent miscibility when mixed with a water-soluble resin. On the other hand, when the amount of polyvinyl alcohol in the surfactant for total emulsification is less than 70% by mass, the miscibility with the water-soluble resin mixed with the silicone emulsion becomes insufficient, and the release agent coating stability is deteriorated over time. Tend to decline.

Further, the surfactant for emulsification preferably contains one or more surfactants other than polyvinyl alcohol (hereinafter referred to as other surfactants).
Examples of other surfactants include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene polystyryl phenyl ether, polyoxyethylene / polyoxypropylene glycol, polyoxyethylene / polyoxypropylene alkyl ether, Polyhydric alcohol fatty acid partial ester, polyoxyethylene polyhydric alcohol fatty acid partial ester, polyoxyethylene fatty acid ester, polyglycerin fatty acid ester, polyoxyethylenated castor oil, fatty acid diethanolamide, polyoxyethylene alkylamine, triethanolamine fatty acid moiety Nonionic surfactants such as esters and trialkylamine oxides may be mentioned.
When other surfactant is contained in the surfactant for emulsification, the content thereof is 0.1 to 30% by mass in the total surfactant for emulsification (that is, the content of polyvinyl alcohol is 70 to 99.9). % By mass). If other surfactant is contained in an amount of 0.1% by mass or more, the emulsion stability of the silicone component is improved.
The amount of the surfactant for emulsification is preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the total amount of the organopolysiloxane and the organohydrogenpolysiloxane.

Since the particle size of the silicone component in the silicone emulsion is more excellent in stability, the number average particle size is preferably in the range of 300 to 400 nm.
The silicone emulsion contains a platinum catalyst for the purpose of accelerating the crosslinking reaction between the organopolysiloxane having an alkenyl group and the organohydrogenpolysiloxane. The platinum catalyst is preferably contained in an amount of 5 to 50 ppm of platinum based on the total siloxane.

 This silicone emulsion is obtained by a phase inversion emulsification method in which a surfactant other than polyvinyl alcohol and at least one polyvinyl alcohol is added to organopolysiloxane and organohydrogenpolysiloxane, and after vigorous stirring, water is added to perform phase inversion. Can do.

Examples of the water-soluble resin contained in the release agent paint include acrylic resins such as polyvinyl alcohol, starch, carboxymethyl cellulose, hydroxyethyl cellulose, polyvinyl pyrrolidone, polyacrylic acid, and polyacrylamide, and urethane resins. Among these, polyvinyl alcohol, starch, carboxymethyl cellulose, hydroxyethyl cellulose, and polyvinyl pyrrolidone are preferable because they have excellent solvent resistance and the peel strength becomes weaker when an adhesive is applied.
Further, as the water-soluble resin, completely saponified polyvinyl alcohol having a saponification degree of 90% or more is particularly preferable because the release agent layer has higher water resistance and solvent resistance. In contrast, partially saponified polyvinyl alcohol and starch having a low saponification degree have low water resistance of the resin itself and low water resistance of the release agent layer. For example, when an emulsion adhesive is applied on the release agent layer, The peeling force tends to increase.
Further, as the water-soluble resin, polyvinyl alcohol having a degree of polymerization of 1000 or less is preferable because the coating / drying load is further reduced. In contrast, polyvinyl alcohol having a degree of polymerization exceeding 1000 is excellent in water resistance and solvent resistance of the coating film, but the viscosity of the coating becomes extremely high. Therefore, it is necessary to lower the coating concentration in order to impart coating suitability. . For this reason, there is a tendency to give a large load to the coating and drying of the paint.

  The release agent coating used in the present invention is a mixture of the silicone emulsion and a water-soluble resin. The mixing ratio of the silicone emulsion and the water-soluble resin may be appropriately selected according to the target peeling force. However, when particularly reducing the peeling force, the mass ratio of the silicone emulsion / water-soluble resin is 90 to 20 / It is preferable to set it as about 10-80.

  As described above, the release substrate of the present invention is obtained by directly applying a release agent coating containing a specific silicone emulsion to a paper substrate that has not been subjected to sealing treatment. Unlike solvent-free silicones dispersed in or solvent-free silicones that do not contain any organic solvents, the penetration rate is slow, so that they do not easily penetrate into paper substrates. Moreover, since the release agent paint contains a water-soluble resin and has a high viscosity, it is difficult to soak into the paper substrate. Therefore, this release base material has a release agent layer uniformly provided on a paper base material, and has high release characteristics. Therefore, the peelable substrate of the present invention is excellent in recyclability because it is not necessary to use a paper substrate subjected to sealing treatment.

<Method for producing release substrate>
1st Embodiment of the manufacturing method of the peeling base material of this invention is described.
[Coating process]
In the manufacturing method according to the first embodiment, first, in the coating step, a release agent paint containing the above-described silicone emulsion and water-soluble resin is applied to a paper substrate to form a release agent paint film.
As a device for applying the release agent coating to the paper substrate, known coating machines such as a roll coater, knife coater, bar coater, air knife coater, gravure coater, curtain coater, lip coater, and die coater can be used. The coating amount of the release agent coating is preferably in the range of about 0.5 to 10 g / m ² in terms of dry mass. If the coating amount is less than 0.5 g / m ² , the resulting peeling properties may be insufficient, and if it exceeds 10 g / m ² , the peeling properties will be saturated, resulting in poor economic efficiency.
When applying the release agent paint, it is preferable not to use a suction system that sucks the paper substrate from the back side for tension cut. When the suction system is not used, since the penetration of the release agent paint into the paper substrate is suppressed, a more uniform release agent layer can be provided.
The speed at which the release agent coating is applied to the paper substrate is preferably as fast as possible within the range in which the release agent coating is dried in the drying step and the silicone can be cured.

[Drying process]
(Preliminary drying)
Next, after the coating process, the coating film of the release agent paint is preliminarily dried at less than 100 ° C. This preliminary drying may be performed without heating, or may be performed by heating at less than 100 ° C. in a heat drying oven, but is preferably performed at less than 100 ° C. during the preliminary drying. When heated at less than 100 ° C., it can be strongly dried from the initial stage of drying in the main drying, so that the coating speed can be increased. Moreover, when pre-drying by heating at less than 100 ° C., it is preferable not to use a floating dryer that quickly blows hot air from the front and back of the paper substrate. When a floating dryer is used, there is a possibility that the peeling characteristics may not be improved.

(Dry drying)
After preliminary drying, the coating film is fully dried at 100 ° C. or higher, preferably 110 to 170 ° C., more preferably 120 to 140 ° C., to provide a release agent layer. In this manner, a release substrate in which a release agent layer is directly provided on a paper substrate can be obtained.
In such a drying step, when heating is performed by preliminary drying, one each of the preliminary drying and the main drying may be performed by using one thermal drying oven, or a plurality of thermal drying ovens may be used.

  Moreover, the manufacturing method of the peeling base material of 2nd Embodiment first performs an application | coating process similarly to 1st Embodiment, 3 seconds or more after completion | finish of an application | coating process, Preferably it peels after 3 to 30 second passes. The coating film of the agent paint is finally dried as in the first embodiment. As described above, when the main drying is performed after 3 seconds or more have elapsed from the end of the coating process, a bypass roll for bypassing the route to the heat drying oven at 100 ° C. or higher for performing the main drying is provided, and the release agent coating is applied. What is necessary is just to pass through the bypass roll after apply | coating.

As in the above-described method for producing a release substrate, after the coating process, the coating film of the release coating is pre-dried at less than 100 ° C., or by providing an interval of 3 seconds or more from the end of the coating process to the main drying The silicone component can be transferred to the coating surface layer. In addition, the silicone component can be crosslinked and cured by main drying at 100 ° C. or higher while maintaining the state where the silicone component has been transferred to the surface layer. As a result, since the release agent (silicone component) can be unevenly distributed on the surface of the release agent layer, the release characteristics of the obtained release substrate are enhanced. Further, in this method for producing a release substrate, since the release agent paint is directly applied to the paper substrate and dried, the production is simple and the obtained release substrate is easily dissolved in water. Excellent recyclability.
On the other hand, when the coating film of the release agent coating is pre-dried at 100 ° C. or higher, or when the interval from the end of the coating process to the main drying is less than 3 seconds, the silicone component is sufficiently applied to the coating surface layer. Since it cannot be made to transfer to, peeling characteristics become inadequate.

<Adhesive sheet>
The pressure-sensitive adhesive sheet of the present invention has a support, a pressure-sensitive adhesive layer sequentially provided on at least one side of the support, and a release substrate, and the release substrate described above is used as the release substrate. It is.
There are no particular restrictions on the material of the support, for example, paper such as cast coated paper, art paper, coated paper, high-quality paper, polymer films made of polyethylene, polypropylene, polyethylene terephthalate, and the like, as well as vapor-deposited paper and synthetic paper , Cloth, non-woven fabric, metal foil, etc. are used according to the purpose and application. A laminate in which at least one other layer is provided on one side or both sides of these supports can also be used.
Moreover, there is no restriction | limiting in particular also in an adhesive, For example, emulsion type, such as an acrylic type, a rubber type, a urethane type, a solvent type, a hot-melt type adhesive etc. are mentioned.

As a method for producing this pressure-sensitive adhesive sheet, a transfer method in which a pressure-sensitive adhesive layer is previously provided by applying a pressure-sensitive adhesive on a release layer of a release substrate, and a support is bonded to this pressure-sensitive adhesive layer, There is a direct method in which a pressure-sensitive adhesive layer is applied and then the pressure-sensitive adhesive layer and the release agent layer of the release substrate are bonded together.
Here, as an apparatus for applying the pressure-sensitive adhesive, for example, the same apparatus as that for applying the release agent coating to the paper substrate can be used.
In the adhesive sheet of this invention, since the peeling base material obtained with the manufacturing method of the said peeling base material is used, it is excellent in peeling characteristics.

Next, the adhesive tape of this invention is demonstrated.
<Adhesive tape>
The pressure-sensitive adhesive tape of the present invention has a peeling base material on which one side is peeled off, and a pressure-sensitive adhesive layer provided on the other side of the peeling base material. A substrate is used. This pressure-sensitive adhesive tape is the same as the above-mentioned pressure-sensitive adhesive sheet except that a release agent coating is applied to one side of a paper substrate, and is excellent in peeling properties.
This pressure-sensitive adhesive tape is used in a roll form. As the adhesive, the same ones as described above can be used.
As a method for producing an adhesive tape, a transfer method in which an adhesive is applied on a release agent layer of an arbitrary release paper to provide an adhesive layer, and a release substrate is bonded to the adhesive layer, a paper base of the release substrate is provided. There is a direct method in which an adhesive is directly applied to a material. After providing each layer, the obtained pressure-sensitive adhesive tape is wound into a roll.

Hereinafter, the present invention will be described more specifically by way of examples. However, the present invention is not limited to these examples. In the examples, “parts” and “%” represent “parts by mass” and “mass%”, respectively, unless otherwise specified.
Example 1
Completely saponified polyvinyl alcohol (trade name: PVA105, manufactured by Kuraray, saponification degree 98%, polymerization degree 500), which is a water-soluble resin, is mixed with the silicone emulsion so that the solid content is 60/40, and the concentration becomes 20%. A release agent paint was prepared by diluting with water.
Here, the silicone emulsion is prepared in advance as follows. That is, an organopolysiloxane as a base polymer is added to a 1 liter composite emulsifying device having a vertical stirring device capable of stirring the entire interior of a container and a rotatable disk having small tooth-shaped protrusions alternately provided on the periphery thereof. 100 parts (vinyl group content 0.02 mol / 100 g), 4 parts methylhydrogenpolysiloxane (SiH group content 1.6 mol / 100 g) as a crosslinking agent, polyoxyethylene lauryl as a surfactant for emulsification 1 part of ether and 40 parts (solid equivalent: 4 parts) of polyvinyl alcohol (10% aqueous solution) having a saponification degree of 95% were charged and mixed uniformly.
To this mixture, 10 parts of water was added for phase inversion, followed by stirring for 30 minutes. Thereafter, additional water was added to obtain an O / W type silicone emulsion having a solid concentration of 40%. Next, 20 ppm of platinum catalyst (in terms of platinum amount) was added.
Next, in the paint process, the release agent paint is applied to one side of a commercially available high-quality paper (trade name: 0ET50, made by Oji Paper Co., Ltd.) by a bar coater so that the dry weight becomes 3 g / m ^2. did. Subsequently, in the drying step, the coating film of the release agent paint is pre-dried for 3 seconds or more in a roll support type first heat drying oven (length 10 m) set at a temperature of 80 ° C. Main drying was performed in a second heat drying oven (length: 15 m) set at 150 ° C., a release agent layer was provided, and release paper as a release substrate was obtained. In addition, the paper surface temperature at the time of this drying measured with the temperature display label (Brand name: Thermo label, NOF Corporation) was 116 degreeC.

(Example 2)
A bypass roll that bypasses the path from the bar coater to the entrance of the heat drying oven was provided, and the high-quality paper on which the same release agent coating film as that of Example 1 was formed was passed through the bypass roll. Then, it is transferred into a roll support type first heat drying oven (length: 15 m) set at a temperature of 140 ° C., and then in a second heat drying oven (length: 10 m) set at a temperature of 150 ° C. The coating film was dried and a release agent layer was provided to obtain a release paper. At that time, the time from the application of the release agent coating to the entry into the first heat drying oven was set to 5 seconds (the processing speed was 60 m / min and the bypass length was 5 m).

(Example 3)
A release paper in the same manner as in Example 1 except that the completely saponified polyvinyl alcohol (trade name: PVA103, manufactured by Kuraray Co., Ltd., saponification degree 98%, polymerization degree 300) was used instead of PVA105. Got.
Example 4
A release paper was prepared in the same manner as in Example 1 except that a completely saponified polyvinyl alcohol (trade name: PVA125, manufactured by Kuraray, saponification degree 98%, polymerization degree 2500) was used instead of PVA105 in the release agent paint of Example 1. Obtained. In this example, the coating viscosity was 8% because the coating viscosity was too high, but the drying load slightly increased because the concentration decreased, and the paper surface temperature during the main drying was 82 ° C.

(Example 5)
A release paper was prepared in the same manner as in Example 1 except that partially saponified polyvinyl alcohol (trade name: PVA205, manufactured by Kuraray, saponification degree 88%, polymerization degree 500) was used instead of PVA105 in the release agent paint of Example 1. Obtained.
(Example 6)
A release paper was obtained in the same manner as in Example 1 except that a water-soluble acrylic resin (trade name: SA513, manufactured by Chuo Rika Kogyo Co., Ltd.) was used instead of PVA105 in the release agent paint of Example 1.
(Example 7)
A release paper was obtained in the same manner as in Example 1 except that a water-soluble urethane resin (trade name: UX235, manufactured by Asahi Denka Kogyo Co., Ltd.) was used instead of PVA105 in the release agent paint of Example 1.
(Example 8)
In the drying process in Example 1, a roll support type first heat drying oven (length: 10 m) set at a temperature of 140 ° C. and a second heat drying oven (length: 15 m) set at a temperature of 150 ° C. A release paper was obtained in the same manner as in Example 1 except that it was dried. In this example, no bypass roll was provided from the bar coater to the entrance of the first heat drying oven, and the paper base material entered the first heat drying oven in less than 3 seconds from the end of coating.

(Comparative Example 1)
The release agent paint of Example 1 was the same as Example 1 except that the amount of polyoxyethylene lauryl ether in the silicone emulsion was 40 parts and the amount of polyvinyl alcohol having a saponification degree of 95% (10% aqueous solution) was 10 parts. A release paper was obtained.
(Comparative Example 2)
A release paper was obtained in the same manner as in Example 1 except that the amount of polyoxyethylene lauryl ether in the silicone emulsion was 10 parts and the polyvinyl alcohol in the surfactant was omitted in the release agent paint of Example 1.

(Comparative Example 3)
A release paper was obtained in the same manner as in Example 1 except that the completely saponified polyvinyl alcohol, which is a water-soluble resin, was not added to the release agent paint of Example 1.
(Comparative Example 4)
In Example 1, a solvent-based silicone release agent (trade name: SRX345, manufactured by Toray Dow Corning, Silicone) was used as the release agent paint instead of the mixture of silicone emulsion and polyvinyl alcohol. A release paper was obtained.

The following evaluation was implemented about the release agent coating material and release agent of each case. The results are shown in Tables 1 and 2.
<Stability of release agent paint>
The release agent paint was observed for 8 hours after standing at room temperature.
○: Separation and aggregation are not recognized in the paint.
Δ: Mild separation or aggregation is observed in the paint, but it can be used by lightly stirring again.
X: Separation and agglomeration are recognized in the paint, and it cannot be used unless it is vigorously stirred again.
<Water resistance of release agent layer>
The surface of the release agent layer was wiped off with a waste cloth containing a commercially available aqueous red ink diluent, and the dyeing condition of the coating film and the pinhole state were visually observed.
○: The coating film is hardly dyed with ink. Or almost no coating pinholes are observed.
X: The coating film is clearly dyed with ink. Or there are many coating film pinholes and there is a problem in practical use.
<Solvent resistance of release agent layer>
The surface of the release agent layer was wiped off with a waste cloth containing a commercially available oily red ink diluent, and the dyeing condition of the coating film and the pinhole state were visually observed.
○: The coating film is hardly dyed with ink. Or almost no coating pinholes are observed.
X: The coating film is clearly dyed with ink. Or there are many coating film pinholes and there is a problem in practical use.

After the release paper of Examples 1 to 8 and Comparative Examples 1 to 4 was cured at room temperature for 1 day, an acrylic emulsion adhesive (trade name: L301, Nippon Carbide) was used on the release agent layer of the release paper using a reverse roll coater. Kogyo Co., Ltd.) was applied and dried to a dry weight of 20 g / m ² to provide an adhesive layer. A commercially available high-quality paper (support) 64 g / m ² was bonded to the pressure-sensitive adhesive layer to prepare a pressure-sensitive adhesive sheet. The following evaluation was implemented about the obtained adhesive sheet. The results are shown in Table 1.
<Peeling force (T-PEEL)>
According to JIS Z 0237, a test piece having a width of 25 mm and a length of 100 mm was peeled off at a peeling speed of 0.3 m / min using an ORIENTEC Tensilon universal testing machine RTC-1210.

As is clear from Table 1, in the release papers of Examples 1 to 8, the release agent coating was excellent in stability over time, and the barrier property and release characteristics of the release agent layer were high.
However, in Example 5 using partially saponified polyvinyl alcohol as the water-soluble resin, Example 6 using water-soluble acrylic resin, and Example 7 using water-soluble urethane resin, fully saponified polyvinyl alcohol was used as the water-soluble resin. In comparison with Examples 1 to 4, the peel strength was somewhat heavy, and the water resistance and solvent resistance of the coating film were slightly low. Further, in Example 8 where preliminary drying was not performed, the peeling characteristics were slightly low. Furthermore, in Example 4 in which the degree of polymerization of the fully saponified polyvinyl alcohol exceeded 1000, it was necessary to dilute with water excessively to adjust the viscosity. As a result, the paper surface temperature was slightly lowered and the silicone curing property was slightly inferior. It became heavy peeling force.

  Compared to these examples, in Comparative Examples 1 and 2 using a silicone emulsion in which the amount of polyvinyl alcohol used as a surfactant is less than 70% of the total amount of surfactant, separation and aggregation of the release agent paint occurred over time. However, the paint stability was low. Further, in Comparative Example 3 not containing a water-soluble resin and Comparative Example 4 using a solvent-based silicone release agent as the release agent paint, the release agent paint penetrated into the high-quality paper, and the release characteristics were low. In particular, the tendency was remarkable in Comparative Example 4.

The peeling base material of this invention can be utilized as peeling base materials, such as a peeling paper of an adhesive sheet, a base material of an adhesive tape, and a process release sheet.

Claims (5)

In a release substrate in which a release agent paint containing a silicone emulsion and a water-soluble resin is applied to a paper substrate,
The silicone emulsion consists of (I) 100 parts by mass of an organopolysiloxane having two or more alkenyl groups in one molecule, and (II) an organohydrogen poly having at least one hydrogen atom directly bonded to a silicon atom in one molecule. A release substrate, wherein 1 to 30 parts by mass of siloxane is emulsified with an emulsifying surfactant containing 70% by mass or more of polyvinyl alcohol. A coating process in which a release agent paint containing a silicone emulsion and a water-soluble resin is applied to at least one side of a paper substrate, and a coating film of the release agent paint is preliminarily dried at less than 100 ° C. after the application step, and then at 100 ° C. A method for producing a release substrate having a drying step for drying,
As a silicone emulsion, (I) 100 parts by mass of an organopolysiloxane having two or more alkenyl groups in one molecule and (II) an organohydrogen poly having at least one hydrogen atom directly bonded to a silicon atom in one molecule A method for producing a release substrate, wherein 1 to 30 parts by mass of siloxane is emulsified with an emulsifying surfactant containing 70% by mass or more of polyvinyl alcohol. Applying a release agent paint containing a silicone emulsion and a water-soluble resin on one side of a paper substrate, and after 3 seconds or more have elapsed from the end of the application process, the coating film of the release agent paint is finally dried at 100 ° C. or higher. A method for producing a release substrate having a drying step,
As a silicone emulsion, (I) 100 parts by mass of an organopolysiloxane having two or more alkenyl groups in one molecule and (II) an organohydrogen poly having at least one hydrogen atom directly bonded to a silicon atom in one molecule A method for producing a release substrate, wherein 1 to 30 parts by mass of siloxane is emulsified with an emulsifying surfactant containing 70% by mass or more of polyvinyl alcohol. A pressure-sensitive adhesive sheet comprising a support, a pressure-sensitive adhesive layer sequentially provided on at least one side of the support, and a release substrate,
The pressure-sensitive adhesive sheet, wherein the release substrate is the release substrate according to claim 1. A pressure-sensitive adhesive tape having a release substrate on which one surface has been subjected to a release treatment, and an adhesive layer provided on the other surface of the release substrate,
The pressure-sensitive adhesive tape, wherein the release substrate is the release substrate according to claim 1.