JPH08217980A - Stripping composition - Google Patents

Abstract

PURPOSE: To obtain a release agent composition which gives peelable coating film excellent in curability, exposure resistance, releasabilty and residual adhesion by adding a platinum catalyst to a blend of four specified polyorganosiloxanes. CONSTITUTION: This composition contains 100 pts.wt. polyorganosiloxane (A) having at least two alkenyl groups bound to an Si atom and the balance of methyl or phenyl groups in the molecule, 5-30 pts.wt. polydimethylsiloxane (B) having at least one OH group bound to an Si atom and the balance of methyl groups in the molecule, 0.1-5.0 pts.wt. polydiorganosiloxane (C) having at least one OH group bound to an Si atom in the molecule and containing 6-20mol% bound aryl groups, a linear polyorganohydrogensiloxane (D) represented by the formula (wherein R<1> is H, methyl, etc.; R<2> is methyl, etc.; and a and b are each a positive integer) and having at least three hydrogen atoms bound to an Si atom in the molecule, with the number of the hydrogen atoms bound to an Si atom being 2.3 to 4.0 for one alkenyl group of component A, and a platinum compound catalyst (E).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stripping composition, and more particularly, to a composition which is cured by a hydrosilylation reaction to form a strippable film showing strippability to an adhesive or tacky substance. It has excellent curability, and the resulting coating has no deterioration in peelability due to exposure of the coated surface to the outside air. It peels with a light peeling force during low-speed and high-speed peeling, and has an excellent residual adhesion rate. The present invention relates to a peeling composition that exhibits stable and light peeling force immediately after curing.

[0002]

2. Description of the Related Art Utilizing the fact that polyorganosiloxane does not show an affinity for various substances but has a releasability for adhesive or tacky substances, various fibers such as paper, synthetic It is well known that the surface of various base materials such as a resin film is treated and a cured film is formed by a crosslinking reaction to be used as a peelable film for an adhesive or tacky substance.

Such curable polyorganosiloxane compositions include polyorganosiloxanes containing alkenyl groups such as vinyl groups bonded to silicon atoms.
An addition reaction-type stripping composition containing a polyorganohydrogensiloxane having a hydrogen atom bonded to a silicon atom as a main component and curing by a hydrosilylation reaction;
Also known is a condensation reaction-type stripping composition which contains a silanol group-containing polyorganosiloxane and the above-mentioned polyorganohydrogensiloxane as main components and cures by dehydrogenative condensation. The addition reaction type is widely used as a peeling composition because it has advantages such as a higher curing speed and a smaller peeling speed dependency of the peeling force than the condensation reaction type. However, the addition reaction type peeling composition has a phenomenon that the peeling performance is lost when the coating film obtained by curing is exposed to the outside air. Therefore, in the process of producing a label or an adhesive tape using a release paper or a release film on which a release coating is formed using an addition reaction type release composition, the coating is exposed to the atmosphere. Then, these products can no longer exhibit the original peeling property and cannot be peeled off, resulting in a serious deterioration in quality.

In order to solve such a problem, a method of blending an alcohol-modified polyorganosiloxane or a polyether-modified polyorganosiloxane with an addition reaction type stripping composition (JP-A-55-3460), And as part of the polyorganohydrogensiloxane,
A method of blending a polysiloxane chain having a hydrosilyl group only on one terminal siloxy group (Japanese Patent Laid-Open No. 1-21)
No. 7068), and a silicone raw rubber having a high vinyl group content and a polyorganohydrogensiloxane having a specific molar ratio, and further compounding a polydiorganosiloxane having a hydroxyl group (JP-A-6-93183).
No. publication) is known. However, JP-A-55-346
In the methods described in JP-A No. 0 and JP-A 1-217068, stability to exposure to the atmosphere as described above (hereinafter referred to as exposure resistance) has some effect, but is not sufficient. There is a problem that the amount of transfer of the release agent to the adhesive layer is increased and the residual adhesive strength is reduced.
On the other hand, the method described in Japanese Patent Application Laid-Open No. 6-93183 has a problem that the peeling force immediately after curing is heavy and it takes days until the peeling force is stabilized. In particular, when processed at low temperature such as in winter, the peeling force is heavy and unstable, so that it may happen that the product cannot be shipped for a long time.

The present inventors have previously reported that the content of Si-H bond in polyorganohydrogensiloxane used as a cross-linking agent, and the vinyl bonded to the silicon atom in the Si-H bond and the vinyl group-containing polyorganosiloxane. By limiting the ratio with the group to a specific range, a stripping composition having excellent exposure resistance was obtained (JP-A-6-322).
295). However, as the demands for release papers and release films have further diversified, there has been a demand for release compositions that provide a release coating that comprehensively satisfies various properties.

That is, in the case of producing an adhesive paper using a release paper or a release film, the release is performed at a high speed in order to improve the productivity in the rewinding process, the scraping process and the labeling process in the manufacturing process. Is needed. Even with a peelable coating that shows a light peeling force at low speed, when peeling at high speed, the peeling force may become extremely heavy, so it is important to reduce the peeling force at the time of high speed peeling. It has become a challenge. In order to improve the high-speed peelability, a method of blending a non-reactive aryl group-containing polyorganosiloxane with an addition reaction type peeling composition (JP-A-60-133051),
A method of blending a polyorganosiloxane having a hydroxyl group at the terminal and containing an aryl group (JP-A-3-9385).
No. 8) and, as the alkenyl group-containing polyorganosiloxane, a method in which a polyorganosiloxane having a high vinyl group content and containing a phenyl group and a polyorganosiloxane having a low vinyl group content are used in combination (Japanese Patent Application Laid-Open No. H8-242242). No. 187466) is known. But,
These methods have some effect in reducing the peeling force at the time of high-speed peeling as described above, but are not sufficient. Particularly, in the method described in JP-A-3-93858, the above-mentioned Those having a small amount of polyorganosiloxane having a hydroxyl group and containing an aryl group have a large peeling force at the time of low-speed peeling, and those having a large amount of addition result in an extremely low residual adhesion ratio. Not practical.

[0007] It has been required to impart a plurality of characteristics to differentiate the release paper and the release film used for the recent adhesive products. However, as described above, even if the exposure resistance is imparted, the peeling force immediately after curing is heavy, and it takes days to stabilize the peeling force, or even if the peeling force at the time of high-speed peeling is reduced, The obtained peelable coating film has merits and demerits, such as a large peeling force, and it has been difficult to provide a peelable coating film that can sufficiently satisfy a plurality of characteristics.

[0008]

SUMMARY OF THE INVENTION The present invention is to solve the problems of such an addition reaction type stripping composition,
Its purpose is excellent in curability and exposure resistance, peeling with low peeling force at low speed and high speed peeling, and showing stable peeling force immediately after curing without lowering migration property and residual adhesion rate. It is to provide a composition.

[0009]

Means for Solving the Problems As a result of intensive studies to solve this problem, the present inventors have used an alkenyl group-containing polyorganosiloxane as the component (A),
A high-molecular-weight polydimethylsiloxane (B) having a hydroxyl group in a stripping composition that is cured by an addition reaction with the polyorganohydrogensiloxane that is the component (D).
And a specific amount of a polydiorganosiloxane (C) having a hydroxyl group and containing an aryl group,
Problems to be solved by the present invention, namely, exhibiting excellent curability, exposure resistance, light peeling force during low-speed and high-speed peeling, and exhibiting stable peeling force immediately after curing. The present invention has been completed by finding that there is an excellent effect in providing a protective coating.

That is, the present invention provides the following component (A),
The present invention relates to a peeling composition containing a component (B), a component (C), a component (D) and a component (E).

(A) It has two or more alkenyl groups bonded to silicon atoms in one molecule, the remaining organic groups bonded to silicon atoms are methyl groups or phenyl groups, and the viscosity at 25 ° C. is 50 cP or more. 100 parts by weight of a certain polyorganosiloxane; (B) having at least one hydroxyl group bonded to a silicon atom in one molecule, the organic group bonded to the silicon atom is a methyl group, and a 30 wt% toluene solution at 25 ° C. Viscosity 1
Polydimethylsiloxane of over 30,000 cP 5-30
Parts by weight; (C) 6 to 2 aryl groups each having at least one silicon-bonded hydroxyl group in the molecule and bonded to a silicon atom.
Contains 0 mol% and has a viscosity at 25 ° C. of 5,000 to
500,000 cP polydiorganosiloxane 0.1
To 5.0 parts by weight; (D) Linear polyorganohydrogensiloxane represented by formula (I) having at least 3 hydrogen atoms bonded to silicon atoms on average in one molecule, and hydrogen bonded to silicon atoms The amount of the atom to be 2.3 to 4.0 per 1 alkenyl group in the component (A),

Embedded image (In the formula, R ^{1 s} may be the same or different, and each represents a hydrogen atom, a methyl group or a phenyl group; R ²
They may be the same or different from each other and represent a methyl group or a phenyl group; a and b each represent a positive integer; the ratio of the number of Si—H bond-containing siloxane units to the total number of siloxane units is 0.45. .About.1.00); (E) Platinum or platinum compound Catalytic amount.

The composition of the present invention will be described in more detail below.

<Component (A)> The alkenyl group-containing polyorganosiloxane of component (A) is a component used as a base polymer in the stripping composition of the present invention. The component (A) has two or more alkenyl groups directly bonded to a silicon atom in one molecule, and the alkenyl groups form a network structure by the reaction with the hydrosilyl group of the component (D) described later. Thus, it is possible to cure and form a peelable coating. The alkenyl groups are preferably bonded to different silicon atoms, and may be bonded to either a terminal silicon atom of the siloxane chain or an intermediate silicon atom. In order to obtain a film having excellent mechanical strength, it is more preferable that an alkenyl group is bonded to at least a terminal silicon atom of a siloxane chain.

Alkenyl groups include vinyl, allyl,
Butenyl, hexenyl and the like are exemplified, and a vinyl group is preferable since good peeling properties can be obtained.

As described above, the amount of alkenyl groups is 2 or more in one molecule, and the curability, the physical properties of the coating film after curing, the amount of components that migrate from the coating film to the adhesive layer are small, and the residual adhesion ratio is low. Since it is high and the base polymer is easily produced, the alkenyl group-containing siloxane unit is preferably in the range of 0.5 to 10 mol% in all siloxane units.
-6 mol% is particularly preferred.

The organic group other than the alkenyl group bonded to the silicon atom is such that the coating film obtained by curing has excellent releasability, mechanical strength and fluidity before curing, and further has the exposure resistance which is the object of the present invention. Therefore, it is substantially a methyl group or a phenyl group. In particular, 85% or more of the organic groups are preferably methyl groups, and more preferably all methyl groups, in order to impart excellent exposure resistance to the coating.

The siloxane skeleton of the component (A) may be linear or branched, and these may be used as a mixture in order to impart excellent mechanical properties to the coating. As described above, the viscosity at 25 ° C. is 50 cP or more, preferably 100 cP or more. If the viscosity is less than 50 cP, sufficient peelability and mechanical strength cannot be given to the cured film, especially when using a substrate such as glassine paper or kraft paper,
If the viscosity is low, there is a tendency that the base material penetrates a lot and the peelability is poor when the same treatment amount is used.

<Component (B)> The component (B) has at least one hydroxyl group bonded to a silicon atom in one molecule, and the organic group bonded to the silicon atom is a methyl group. Is a silicone rubber-like high molecular weight polydimethylsiloxane having a viscosity of 10,000 cP or more at 25 ° C. The polydimethylsiloxane is a component for reducing the peeling force and developing the exposure resistance in the peeling composition of the present invention. Because it is easy to handle,
The viscosity of the 30 wt% toluene solution of component (B) at 25 ° C is preferably in the range of 10,000 to 1,000,000 cP, particularly preferably in the range of 15,000 to 100,000 cP. This polydimethylsiloxane having a viscosity of less than 10,000 cP does not provide a sufficient effect on light release and exposure resistance, and further deteriorates migration.
This leads to a decrease in the residual adhesion rate. The hydroxyl group may be bonded to either a terminal silicon atom of the siloxane chain or an intermediate silicon atom, but it is preferably bonded to a terminal silicon atom from the viewpoint of easy synthesis, and each of the silicon atoms at both terminals has 1
It is more preferable that each hydroxyl group is bonded.

In general, non-reactive polydimethylsiloxane may be used as a component for reducing the peeling force, but the migration property of the peelable coating is increased, and the residual adhesion rate is deteriorated. However, the component (B) used in the present invention does not increase the transferability or decrease the residual adhesion rate while maintaining the property of reducing the peeling force.

The blending amount of the component (B) is 100 parts of the component (A).
It is in the range of 5 to 30 parts by weight, and 10 to 2 parts by weight.
0 parts by weight is preferred. If it exceeds 30 parts by weight, the peeling force at low speed becomes light, but the peeling force at high speed becomes heavy on the contrary, which causes problems such as deterioration of transferability and reduction of residual adhesion rate. Further, if it is less than 5 parts by weight, sufficient light peeling property and exposure resistance cannot be exhibited.

<Component (C)> The component (C) has at least one hydroxyl group bonded to a silicon atom in one molecule and contains 6 to 20 mol% of an aryl group bonded to a silicon atom. It is a polydiorganosiloxane having a viscosity at 500C of 500 to 500,000 cP. The aryl group-containing polydiorganosiloxane is a component for exhibiting stable light peelability immediately after curing in the peeling composition of the present invention. When the above-mentioned component (B) is used alone without being used together with this component (C), a light peeling force is exhibited,
The peeling force immediately after curing is heavy, and it takes several days until the above light peeling property is sufficiently exhibited. By combining the components (B) and (C) in combination, unexpectedly, stable and good light peeling property can be obtained immediately after curing, and migration and residual adhesiveness are not reduced. The effect is obtained.

The aryl groups contained in the component (C) may be the same or different, and examples thereof include phenyl and tolyl, and a phenyl group is preferable because good peeling properties can be obtained. The content of such an aryl group is 6 to
It is 20 mol%, preferably 8 to 16 mol%. When the aryl group is less than 6 mol%, it is difficult to develop a stable and light peeling force immediately after curing, and when it exceeds 20 mol%, the effect is not improved. On the other hand, the component (A) and the component (B) are not improved. Since the compatibility between and becomes poor and the component (C) is not uniformly dispersed, it causes deterioration of the transferability to the peelable coating and a decrease in the residual adhesion rate. The aryl group may be attached to any silicon atom of the siloxane chain. In the case of an intermediate silicon atom, the number of aryl groups bonded to the silicon atom may be one or two. Examples of the residual organic group bonded to the silicon atom include alkyl groups such as methyl, ethyl, propyl, butyl, and pentyl. However, since they are easy to synthesize and handle, and have excellent physical properties and release properties, It is preferable that all are methyl groups. The hydroxyl group may be bonded to either a terminal silicon atom of the siloxane chain or an intermediate silicon atom, but it is preferably bonded to a terminal silicon atom from the viewpoint of easy synthesis, and each of the silicon atoms at both terminals has More preferably, one hydroxyl group is bonded.

The viscosity of the component (C) at 25 ° C. is 5,0.
00 to 500,000 cP, 10,000 to 30
It is preferably 10,000 cP. Viscosity is 5,000
If it is less than cP, not only is it difficult to develop a stable light peeling force immediately after curing, but also the residual adhesion rate is reduced. On the other hand, when the viscosity exceeds 500,000 cP, the effect of exhibiting a stable and light peeling force immediately after curing is small.

The blending amount of the component (C) is 100 parts of the component (A).
0.1 to 5.0 parts by weight with respect to parts by weight,
2.0 parts by weight is preferred. If it is less than 0.1 part by weight, it is difficult to develop a stable light peeling force immediately after curing,
If it exceeds 5.0 parts by weight, the migration property and the residual adhesion rate are significantly lowered.

Further, when the total amount of the component (B) and the component (C) is 10 to 20 parts by weight with respect to 100 parts by weight of the component (A), the curability and the exposure resistance are excellent, and the migration is improved. It is most preferable in the present invention because it exhibits stable and light peeling force immediately after curing without lowering the property and the residual adhesion rate.

<Component (D)> The polyorganohydrogensiloxane of component (D) is a component used as a crosslinking agent in the stripping composition of the present invention. That is, the hydrosilyl group contained in the component (D) performs an addition reaction with the alkenyl group in the component (A) to form a network structure. Therefore, the number of hydrogen atoms directly bonded to silicon atoms in the component (D) needs to be at least 3 on average in one molecule. Further, the polyorganohydrogensiloxane has the following properties in order to cure the composition to give a release agent coating having excellent exposure resistance.
It is necessary to have a specific molecular structure as well as a ratio of the number of Si-H bond containing siloxane units to the total number of siloxane units. Such a polyorganohydrogensiloxane is a linear polyorganohydrogensiloxane represented by the following formula (I).

[0027]

Embedded image

(In the formula, R ¹ , R ² , a and b are as described above) The formula (I) simply represents the constitutional ratio of siloxane units, and the linear polyorganohydrogensiloxane is The former is generally used regardless of whether it is a random copolymer or a block copolymer. In the formula (I), the siloxy groups at both terminals may be hydrogen atoms, methyl groups or phenyl groups as R ¹ . When R ^{1 at} both ends is a hydrogen atom, the number a ′ of Si—H bond-containing siloxane units in the polyorganohydrogensiloxane is a + 2. When R ^{1 at} one end is a hydrogen atom, a ′ above is a + 1, and R at both ends is R 1.
^{When 1} is a methyl group or a phenyl group, a'is equal to a. Such a'and the number of all siloxane units (a +
The ratio a ′ / (a + b + 2) of b + 2) is 0.45 to 1.0
The range is 0, preferably 0.45 to 0.75. If this value is less than 0.45, the rate of the addition reaction at the time of curing will be slow and the curability will be poor.

Organic group bonded to silicon atom, ie R
¹ (excluding the case of hydrogen atom) and R ² are methyl groups or phenyl groups, since they give excellent release resistance to the peelable coating obtained by curing, and R ² is 85% of the organic group in the molecule. % Or more is preferably a methyl group, more preferably all methyl groups.

The viscosity is not particularly limited, but the viscosity at 25 ° C. is 500 cP because it is easy to synthesize and handle.
The following is preferred.

The blending amount of the component (D) is 2.3 to 4.0 hydrogen atoms bonded to silicon atoms in the component (D) per one alkenyl group in the component (A). Quantity,
Due to this, the peelable coating obtained by curing has excellent exposure resistance. Further, within the above range, the amount of the component (D) is 0.5 to 1 with respect to 100 parts by weight of the component (A).
The average molecular weight of both components, the content of the alkenyl group bonded to the silicon atom of the component (A), and the content of the hydrogen atom bonded to the silicon atom of the component (D) are selected so as to be 00 parts by weight. It is preferable. This amount is 0.5
When the amount is less than the weight part, it is difficult to uniformly disperse the component (B) in the component (A) in a short time, which causes a limitation in work.
Also, in a combination where this amount exceeds 100 parts by weight,
The residual adhesion rate decreases and the transferability deteriorates.

<Component (E)> The platinum or platinum compound of component (E) acts as a catalyst for the hydrosilylation reaction between the alkenyl group in component (A) and the Si-H bond in component (D). It is a curing catalyst, and a platinum compound is preferable from the viewpoint of catalytic effect. Examples of the platinum compound include chloroplatinic acid, a reaction product of chloroplatinic acid and an alcohol, a platinum-olefin complex, a platinum-vinylsiloxane complex, a platinum-phosphorus complex, and a platinum coordination compound.

The amount of the component (E) blended is an effective amount as a catalyst, and is usually in the range of 1 to 500 ppm as platinum atom based on the total amount of the components (A) and (D).
300 ppm is preferred. If it is less than 1 ppm, the curing is very slow and there is a practical disadvantage, and if it exceeds 300 ppm, the corresponding improvement in the curing rate cannot be expected, which is not preferable in terms of economy and stability.

<Other Additives> If desired, known additives may be added to the composition of the present invention within a range that does not impair the function of the composition of the present invention. Such additives include inorganic fillers such as fumed silica, pigments such as red iron oxide, cure inhibitors such as 2-methyl-3-butyn-2-ol, and 2-hydroxy-2-methyl. Photosensitizers such as -1-phenylpropan-1-one can be exemplified.

<Method of Use> When the apparent viscosity of the system is low, the composition of the present invention may be applied as it is to a substrate, but in consideration of workability of application and treatment, it may be diluted with a solvent. It is generally used. Solvents include benzene, toluene,
Aromatic hydrocarbons such as xylene; aliphatic hydrocarbons such as heptane and hexane; halogenated hydrocarbons such as tetrachloroethylene; esters such as ethyl acetate and butyl acetate; and ketones such as methyl ethyl ketone and methyl isobutyl ketone; and mixtures thereof. It is illustrated.

The composition of the present invention is usually (A) to (D)
The components and, if necessary, additives and solvents are mixed, and the component (E) separately prepared or a solution thereof is mixed immediately before use and coated on the substrate. If necessary, the component (D) may be stored separately, or a mixture of the components (A) to (D) in the presence of a curing inhibitor or a solution thereof may be stored.

As the substrate, glassine paper, kraft paper,
Examples include, but are not limited to, paper or paper composite materials such as parchment paper and polyethylene laminated paper; and plastic films such as polyethylene film and polypropylene film.

After coating, if a solvent is present, the solvent is dried to remove the solvent, and then heated to cure to form a peelable coating on the surface of the substrate. The heating condition is usually a temperature of 100 to 1
It is 10 to 30 seconds at 50 ° C.

[0039]

The stripping composition of the present invention has excellent curability,
The peelable coating obtained by curing it is excellent in exposure resistance, peels with a light peeling force at low speed and high speed peeling, and has no migration property or residual adhesion rate. Above all, it shows stable light peeling force immediately after curing. Therefore, the release paper or the release film having the release coating film obtained from the release composition of the present invention formed on the surface of the base material does not increase the release force even when the release agent coated surface is exposed to the outside air. In addition, the peeling force at low speed and high speed peeling is light, and the transferability and residual adhesion rate are excellent, and even if it is processed at low temperature such as in winter, it shows a stable light peeling force immediately after curing, so in terms of quality stabilization It is advantageous and has great industrial significance.

[0040]

The present invention will be described in more detail with reference to the following examples and comparative examples. The invention is not limited by these examples. In the following Examples and Comparative Examples, parts represent parts by weight, and the viscosity shows a value at 25 ° C.

In Examples and Comparative Examples, various polysiloxanes shown in Table 1, that is, A-1 to (A) as the component (A) were used.
A-3, B-1 to B-3 as the component (B), C-1 to C-7 as the component (C), and D- as the component (D).
1 and D-2 were used. Of these, B-2 and B-
3 and C-4 to C-7 are polyorganosiloxanes for comparison. In the following description and the molecular structural formulas in Table 1, siloxane units are represented by the following abbreviations. The molecular structural formula means the constitutional ratio of siloxane units, and each polysiloxane is a random copolymer. _{M: (CH 3) 3 SiO} 1/2 units _{M': (CH 3) 2 HSiO} 1/2 unit ^{_{M v: (CH 3) 2}} (CH 2 = CH) SiO 1/2 unit M ^OH: HO (CH ₃ ) ₂ SiO _1/2 unit D: (CH ₃ ) ₂ SiO unit D ': (CH ₃ ) H SiO unit D ^v : (CH ₃ ) (CH ₂ = CH) SiO unit D ^ph2 : (C ₆ H ₅ ). ₂ SiO unit

[0042]

[Table 1]

Further, as the component (E), E-1 which was a platinum-vinylsiloxane complex obtained from chloroplatinic acid and tetravinyltetramethylcyclotetrasiloxane and had a platinum content of 4,500 ppm was used. In addition, as a curing inhibitor, 2-methyl-3-butyne-2 may be added, if necessary.
-All, toluene was used as the solvent.

Examples 1 to 6 and Comparative Examples 1 to 13 Components (A) to (E), and optionally a curing inhibitor and a solvent were blended at the blending ratios shown in Table 2,
The treatment liquids of Examples 1 to 6 and Comparative Examples 1 to 13 were prepared by stirring and mixing until they became uniform. In Table 2, A-2, A-3, B-1 to B3 and C-1 to
C-7 indicates the number of parts added in the state of a 30 wt% toluene solution.

For example, the treatment liquid of Example 1 was prepared as follows. That is, a polymethylvinylsiloxane A-1 having a degree of polymerization of 200 and having both ends blocked with dimethylvinylsilyl groups and comprising 2.0 mol% of methylvinylsiloxane units and the remaining dimethylsiloxane units is 100%.
Part: polydimethylsiloxane having a polymerization degree of 4,500 and having both ends blocked with dimethylhydroxysilyl groups (the viscosity of a 30 wt% toluene solution at 25 ° C. is 15,000).
cP) 10 parts of B-1; polymethylphenylsiloxane having both ends blocked with dimethylhydroxysilyl groups and consisting of 10.0 mol% of diphenylsiloxane units and the remaining dimethylsiloxane units (viscosity at 25 ° C. of 20,000).
0 cP) 2.0 parts of C-1; both ends blocked with trimethylsilyl groups, and a methylhydrogensiloxane unit 58
6.76 parts of polymethylhydrogensiloxane (polymerization degree 62) D-1 consisting of mol% and the remaining dimethylsiloxane units; and 0.1 part of 2-methyl-3-butyn-2-ol were uniformly mixed. After that, 4.12 parts of platinum-vinylsiloxane complex E-1 was added to prepare a treatment liquid. For one Si-Vi bond in A-1, D-1
The amount of Si-H bonds therein was 2.5.

[0046]

[Table 2]

These treatment liquids were applied to polyethylene laminated paper having a density of 75 g / m ² so that the coating amount after drying would be 0.8 g / m ^2, and heated at 100 ° C. for 20 seconds to cure, A peelable coating was formed on the surface of polyethylene laminated paper.

The peelable coating thus obtained was evaluated as follows. As a result, the results shown in Table 3 were obtained.

[0049]

[Table 3]

<Peeling power (low speed)> After curing, the surface of the peelable coating which was hermetically sealed in a paper container and aged at 25 ° C. and 50% RH for 1 day was coated with an acrylic solvent type adhesive Olivain BP.
S-8170 (trade name, manufactured by Toyo Ink Co., Ltd.) was applied to a wet thickness of 88 μm, and dried at 100 ° C. for 3 minutes. Next, a high-quality paper having a unit weight of 60 g / m ² was laminated on it, and the whole was cut into a strip shape having a width of 5 cm. This is 2
Under a load of 0 g / cm ² , temperature 25 ℃, relative humidity 50%
The sample was aged under the conditions of 1 day. This sample was pulled in a 180 ° direction at a speed of 0.3 m / min by a tensile tester, and the force required for peeling was measured.

<Peeling force (high speed)> The above peeling force (low speed)
The sample produced in the same manner as in the evaluation method of 1. was pulled in a 180 ° direction at a speed of 60 m / min by a tensile tester, and the force required for peeling was measured.

<Peeling Force (After Exposure)> The sample having a peelable coating obtained by curing was exposed to the air outdoors for 4 hours with the treated surface facing upward. Using this, the peeling force was measured under the same measurement conditions as the peeling force (low speed).

<Peeling force (after 3 days)> After curing, the sample was sealed in a paper container and aged for 3 days at 25 ° C and 50% RH. The peeling force was measured under the same measurement conditions as the peeling force (low speed). Was measured.

<Residual Adhesive Strength> A 2.5 cm wide Nitto 31B adhesive tape (Nitto Denko Corporation) on the surface of the peelable coating.
Made, product name) is pasted. This was left at 70 ° C. for 20 hours under a load of 20 g / cm ² , the tape was peeled from the surface of the release agent coating, and the surface in contact with the release agent was attached to a stainless steel plate (JIS C2107). Attached and pressed with a 2 kg roller. What was aged at 25 ° C. for 3 hours was pulled in a direction of 180 ° by a tensile tester, and the peeling force (f) of the tape was measured. On the other hand, attach the same type of adhesive tape to the polytetrafluoroethylene film,
After that, by the same operation, the standard peeling force (f
_o ) was measured. The residual adhesion rate was calculated by the following formula.

[0055]

[Equation 1]

<Migration property> The polyethylene laminated paper provided with the peelable coating as described above was cut into a strip shape having a width of 5 cm. A 25 μm-thick PET film was attached to the peelable coating surface, a load of 100 g / cm ² was applied, and pressure-bonding was performed at 65 ° C. for 20 hours, then peeled off and the PET film surface that was in contact with the peelable coating surface was peeled off. A line was drawn with a magic ink (Hi Mackey: trade name, manufactured by Zebra Co., Ltd.), and the repellency of the ink was observed, and a four-level evaluation was performed.

From the composition shown in Table 2 and the evaluation result of Table 3,
Example 3 is compared with Comparative Examples 12 and 13. The peelable coating film obtained in Example 3 in which the component (B) and the component (C) are used in combination reduces the peeling force (after exposure), the residual adhesion rate, and the migration due to the synergistic effect of both components. Without
Immediately after curing, a stable light peeling force was exhibited. On the other hand, Comparative Example 12 and Comparative Example 13 in which the component (B) or the component (C) was used alone had excellent peeling force (after exposure),
Although the residual adhesion ratio and the migration property were exhibited, the peeling force immediately after curing was heavy, and the change in peeling force with time was observed.

Claims (2)

[Claims] 1. The following component (A), component (B), and (C)
A peeling composition comprising a component, a component (D) and a component (E). (A) A polyorgano having two or more alkenyl groups bonded to silicon atoms in one molecule, the remaining organic groups bonded to silicon atoms are methyl groups or phenyl groups, and having a viscosity at 25 ° C. of 50 cP or more. 100 parts by weight of siloxane; (B) having one or more hydroxyl groups bonded to a silicon atom in one molecule, the organic group bonded to a silicon atom is a methyl group, and the viscosity of a 30 wt% toluene solution at 25 ° C. is 1
Polydimethylsiloxane of over 30,000 cP 5-30
Parts by weight; (C) 6 to 2 aryl groups each having at least one silicon-bonded hydroxyl group in the molecule and bonded to a silicon atom.
Contains 0 mol% and has a viscosity at 25 ° C. of 5,000 to
500,000 cP polydiorganosiloxane 0.1
To 5.0 parts by weight; (D) Linear polyorganohydrogensiloxane represented by formula (I) having at least 3 hydrogen atoms bonded to silicon atoms on average in one molecule, and hydrogen bonded to silicon atoms An amount in which the number of atoms is 2.3 to 4.0 with respect to one alkenyl group in the component (A), (In the formula, R ^{1 s} may be the same or different, and each represents a hydrogen atom, a methyl group or a phenyl group; R ²
They may be the same or different, and each independently represent a methyl group or a phenyl group; a and b each represent a positive integer; .About.1.00); (E) Platinum or platinum compound Catalytic amount. 2. A peelable coating film obtained by curing the peeling composition according to claim 1.