JP2018193463A - Heavy release composition for release sheet, and release sheet - Google Patents

Abstract

To provide a solventless heavy release composition for a release sheet excellent in heavy release effect, suppressed in zipping when releasing, and small in release strength reduction with time after cure, and a release sheet formed with a cured film thereof.SOLUTION: The heavy release composition for a release sheet includes: (A) alkoxysilane having an alkenyl group bonded to one silicon atom in a molecule; (B) a three-dimensional network-structured organopolysiloxane resin having an alkenyl group bonded to at least two silicon atoms in a molecule; (C) organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms in a molecule; and (D) a platinum group metal catalyst.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an addition reaction curable heavy release composition for release sheet that gives an excellent heavy release effect, and a release sheet using the same.

  Conventionally, in order to prevent adhesion and adhesion between a base material such as paper or plastic and an adhesive material, a cured film of an organopolysiloxane composition is formed on the surface of the base material to impart release characteristics. As a method of forming a cured organopolysiloxane film on the above-mentioned substrate surface, the peelable film formation method by addition reaction is excellent in curability and can respond to various peel characteristics requirements from low speed peel to high speed peel. Therefore, it is widely used.

  The method for forming a peelable film by this addition reaction includes a type in which an organopolysiloxane composition is dissolved in an organic solvent, a type in which the composition is dispersed in water using an emulsifier, and a solventless type consisting only of an organopolysiloxane. However, since the solvent type has a drawback that it may be harmful to the human body and the environment, switching from the solvent type to the solventless type is progressing from the viewpoint of safety.

In general, organopolysiloxane compositions for release paper are required to have various peeling forces depending on the purpose. For applications requiring heavy peeling, an alkenyl group-containing MQ resin (What is M unit?) R ′ ₃ SiO _1/2 units and Q units mean SiO _4/2 units, and R ′ represents a monovalent hydrocarbon group.

  However, alkenyl group-containing MQ resins are often resinous or high-viscosity compounds, and when added in large amounts, they cannot be used unless they are diluted in an organic solvent. Further, if it is added in a small amount, it can be used without a solvent, but in that case, the heavy peeling effect is insufficient. Further, it is known that the alkenyl group-containing MQ resin has a tendency that the peeling force decreases with time as compared with the peeling force immediately after curing, and a resin having no change in peeling force with time is required.

  On the other hand, when peeling the tape from the heavy release sheet, peeling sound (zipping) may be a problem. Although there are many unclear parts regarding the detailed mechanism of zipping, there is a tendency that zipping is likely to occur particularly in a highly-peeled sheet with high crosslink density. Therefore, in developing a heavy release sheet, suppression of zipping is also an important issue.

  Japanese Patent Publication No. 5-53183 (Patent Document 1) is a combination of an alkenyl group-containing MQ resin and an alkenyl group-free MQ resin in an organopolysiloxane composition for release paper, and the change in peel force over time. However, the effect of heavy peeling is insufficient.

  Japanese Patent No. 2750896 (Patent Document 2) is a composition in which an alkenyl group-containing resin is blended in an organopolysiloxane composition for a solvent-type addition reaction type release paper, and low temperature curability and a peeling force with little change with time are obtained. However, heavy peeling is not the purpose and the peeling force is not large. Furthermore, the following technique has been reported as a method for performing heavy release by adding an organopolysiloxane resin having adhesiveness to an addition reaction type organopolysiloxane composition.

  Japanese Examined Patent Publication No. 6-086582 (Patent Document 3) discloses an adhesive organopolysiloxane protective coating having a partially dehydrated condensation of a curable silicone rubber, a hydroxyl group-containing organopolysiloxane and an MQ unit-containing organopolysiloxane resin. It is. Since the silicone rubber and the organopolysiloxane resin are highly viscous or solid, a solvent is required.

  Japanese Patent Application Laid-Open No. 10-110156 (Patent Document 4) is a technique relating to an organopolysiloxane pressure sensitive adhesive mainly composed of a mixture or partial condensate of vinyl raw rubber and MQ resin. This uses a silicone rubber and requires a solvent, and does not touch the effect as a heavy release composition for release paper.

  In JP 2010-37557 A (Patent Document 5), the molar ratio of (a1) M units to Q units is 0.6 to 1.0, and the hydroxyl group or alkoxy group content is 0.3 to 2. Organopolysiloxane obtained by condensation reaction of 100 parts by mass of MQ resin in the range of 0% by mass and (a2) 20-150 parts by mass of a linear polydiorganosiloxane having an average polymerization degree of 100 to 1,000 having a hydroxyl group or an alkoxy group It is a peeling regulator composed of a resin-organopolysiloxane condensation reaction product. According to Patent Document 6, the peeling force in the examples is only 1.4 to 2.2 times higher at a low speed (0.3 m / min) than in the comparative example without addition of the condensation reaction product. The heavy peeling effect is not obtained. This is because the content of the hydroxyl group or alkoxy group of (a1) used is as low as 0.3 to 2.0% by mass, there are few reaction points with (a2), and it has a crosslinked structure by sufficient condensation. This is presumed to be because there is not.

  Japanese Patent Laid-Open No. 5-329184 (Patent Document 6) is a patent for the purpose of suppressing zipping when peeling a tape from a diaper. A release layer in which an MQ resin is mixed with a silicone release agent, and an AB type It is comprised from the adhesive layer which mixed the block copolymer and the tackifier. According to this patent, although zipping can be suppressed, a solvent is used in the release layer, and only evaluation as an adhesive is performed, and the release characteristics are not mentioned.

  Japanese Patent Laid-Open No. 6-228501 (Patent Document 7) presents a method for increasing the peel strength of a pressure-sensitive adhesive without using an alkenyl group-containing MQ resin. This is a composition in which the crosslinking density is adjusted by using a higher alkenyl group at the crosslinking site, but there is no mention of zipping, and since the alkenyl group-containing MQ resin is not used, the heavy peeling effect is insufficient. is there.

  Japanese Patent Application Laid-Open No. 7-188562 (Patent Document 8) is a heavy release composition using an alkenyl group-containing MQ resin, α, ω-diolefin, and organohydrogenpolysiloxane. Although an alkenyl group-containing MQ resin and α, ω-diolefin have a very high peeling force, no problem with zipping has been raised, and a means to solve this problem has also been suggested. Absent.

Japanese Patent Publication No. 5-53183 Japanese Patent No. 2750896 Japanese Patent Publication No. 6-086582 JP-A-10-110156 JP 2010-37557 A JP-A-5-329184 JP-A-6-228501 JP-A-7-188562

  The present invention has been made in view of the above circumstances, and is excellent in a heavy peeling effect, suppressed zipping at the time of peeling, and further has a little decrease in peeling force with time after curing. And a release sheet on which the cured film is formed.

  As a result of intensive studies to achieve the above object, the present inventors have found that (A) an alkoxysilane having an alkenyl group bonded to one silicon atom in the molecule, and (B) at least in one molecule. A three-dimensional network organopolysiloxane resin having an alkenyl group bonded to two silicon atoms; (C) an organohydrogenpolysiloxane having at least two hydrogen atoms bonded to a silicon atom in one molecule; ) It has been found that a heavy release composition for release sheets containing a platinum group metal-based catalyst has an excellent heavy release effect, suppresses zipping at the time of release, and further reduces the decrease in peel strength over time after curing. In particular, by using an alkoxysilane having an alkenyl group bonded to one silicon atom in the molecule, the heavy release composition for release sheet of the present invention can provide a release sheet without zipping. The headline and the present invention were made.

（式中、Ｒ³は独立に、炭素数６以上の脂肪族不飽和結合を含まない直鎖状、分岐鎖状もしくは環状の非置換または置換の１価炭化水素基を表す。）
で表される化合物から選択されるものである［１］記載の剥離シート用重剥離組成物。
［３］．
前記（Ａ）成分の分子内に１個のケイ素原子に結合したアルケニル基を有するアルコキシシランの揮発分が２０質量％以下である［１］または［２］記載の剥離シート用重剥離組成物。
［４］．
２５℃での粘度が５０〜２，０００ｍＰａ・ｓである［１］〜［３］のいずれかに記載の剥離シート用重剥離組成物。
［５］．
シート状基材表面の片面または両面に、［１］〜［４］のいずれかに記載の剥離シート用重剥離組成物の硬化皮膜を有する剥離シート。
［６］．
硬化皮膜にＴｅｓａ７４７５テープを貼り付けて、１８０°の角度、剥離速度０．３ｍ／分で測定した剥離力が５〜２５Ｎ／２５ｍｍである［５］記載の剥離シート。 Accordingly, the present invention provides the following heavy release composition for release sheet and release sheet.
[1].
(A) The following average composition formula (1):
R ¹ R ² _a Si (OR ³ ) _3-a (1)
(Wherein R ¹ independently represents an alkenyl group, R ² independently represents an unsubstituted or substituted monovalent hydrocarbon group not containing an aliphatic unsaturated bond, and R ³ independently represents 6 or more carbon atoms. A linear, branched or cyclic, unsubstituted or substituted monovalent hydrocarbon group that does not contain an aliphatic unsaturated bond, and a is an integer that satisfies 0 ≦ a ≦ 2.)
An alkoxysilane having an alkenyl group bonded to one silicon atom in the molecule: 20 to 50 parts by mass
(B) The following average composition formula (2):
(R ⁵ ₃ SiO _1/2 ) _l (R ⁴ R ⁵ ₂ SiO _1/2 ) _m (R ⁴ R ⁵ SiO) _n (R ⁵ ₂ SiO) _p
(R ⁴ SiO _3/2 ) _q (R ⁵ SiO _3/2 ) _r (SiO _4/2 ) _s (2)
(Wherein R ⁴ independently represents an alkenyl group, R ⁵ independently represents an unsubstituted or substituted monovalent hydrocarbon group not containing an aliphatic unsaturated bond, provided that at least 80 mol% of all R ⁵ Is a methyl group, and l, m, n, p, q, r, and s are l ≧ 0, m ≧ 0, n ≧ 0, p ≧ 0, q ≧ 0, r ≧ 0, and s ≧ 0, respectively. (However, m + n + q> 0, q + r + s> 0, and l + m + n + p + q + r + s = 1).
A three-dimensional network-like organopolysiloxane resin having an alkenyl group bonded to at least two silicon atoms in one molecule, which is waxy or solid at 25 ° C .: 80 to 50 parts by mass
(However, the sum of component (A) and component (B) is 100 parts by mass.)
(C) The following average composition formula (3):
R ⁶ _b H _c SiO _{(4-bc) / 2} (3)
(Wherein R ⁶ independently represents an unsubstituted or substituted monovalent hydrocarbon group not containing an aliphatic unsaturated bond, and b and c are 0.7 ≦ b ≦ 2.1, 0.001 ≦ c. ≦ 1.0 and a positive number satisfying 0.8 ≦ b + c ≦ 3.0.)
And an organohydrogenpolysiloxane having at least two hydrogen atoms bonded to a silicon atom in one molecule: silicon in component (C) with respect to all alkenyl groups in component (A) and component (B) The amount of hydrogen atoms bonded to the atoms is 0.5-5 moles,
(D) Platinum group metal catalyst: Heavy release composition for release sheet containing an effective amount.
[2].
The alkoxysilane having an alkenyl group bonded to one silicon atom in the molecule of the component (A) is represented by the following formulas (4) to (6):

(In the formula, R ³ independently represents a linear, branched or cyclic unsubstituted or substituted monovalent hydrocarbon group not containing an aliphatic unsaturated bond having 6 or more carbon atoms.)
The heavy release composition for release sheets according to [1], which is selected from the compounds represented by formula (1).
[3].
The heavy release composition for release sheets according to [1] or [2], wherein the volatile content of alkoxysilane having an alkenyl group bonded to one silicon atom in the molecule of component (A) is 20% by mass or less.
[4].
The heavy release composition for release sheet according to any one of [1] to [3], wherein the viscosity at 25 ° C. is 50 to 2,000 mPa · s.
[5].
The release sheet which has the cured film of the heavy release composition for release sheets in any one of [1]-[4] on the single side | surface or both surfaces of a sheet-like base material surface.
[6].
The release sheet according to [5], wherein a Tesa 7475 tape is attached to the cured film, and the peel force measured at an angle of 180 ° and a peel speed of 0.3 m / min is 5 to 25 N / 25 mm.

  Even if compared with the conventional heavy release composition, the heavy release composition for release sheets of the present invention can obtain a very large release force. Moreover, since zipping at the time of peeling is suppressed and the decrease in peeling force with time after curing is small, it is useful as a material for a release sheet for heavy peeling.

In an Example, the measurement result of the peeling force at the time of zipping is shown. In an Example, the measurement result of the normal peeling force which is not zipped is shown.

Hereinafter, the present invention will be described in more detail.
[(A) component]
Component (A) is a component for reducing the viscosity of the composition and adjusting the crosslinking density after curing, and alkenyl bonded to one silicon atom in the molecule represented by the following average composition formula (1) An alkoxysilane having a group.
R ¹ R ² _a Si (OR ³ ) _3-a (1)
(Wherein R ¹ independently represents an alkenyl group, R ² independently represents an unsubstituted or substituted monovalent hydrocarbon group not containing an aliphatic unsaturated bond, and R ³ independently represents 6 or more carbon atoms. A linear, branched or cyclic, unsubstituted or substituted monovalent hydrocarbon group that does not contain an aliphatic unsaturated bond, and a is an integer that satisfies 0 ≦ a ≦ 2.)

In said formula (1), R < ¹ > represents an alkenyl group independently, and carbon number is 2-8 normally, Preferably it is 2-4. Specific examples thereof include a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, and a heptenyl group, and a vinyl group is preferable.

R ² independently represents an unsubstituted or substituted monovalent hydrocarbon group that does not contain an aliphatic unsaturated bond, and is not particularly limited as long as it does not have an aliphatic unsaturated bond. 1-12, preferably 1-10, unsubstituted or substituted monovalent hydrocarbon groups not containing an aliphatic unsaturated bond. Examples of the unsubstituted or substituted monovalent hydrocarbon group not containing an aliphatic unsaturated bond include alkyl groups such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, and a heptyl group; A cycloalkyl group such as a group; an aryl group such as a phenyl group, a tolyl group, a xylyl group and a naphthyl group; an aralkyl group such as a benzyl group and a phenethyl group; a part or all of hydrogen atoms of these groups are a chlorine atom or a fluorine atom , Halogenated alkyl groups such as a chloromethyl group, a 3-chloropropyl group, and a 3,3,3-trifluoropropyl group substituted with a halogen atom such as a bromine atom, and the like, preferably an alkyl group, More preferably, it is a methyl group.

R ³ independently represents a linear, branched or cyclic unsubstituted or substituted monovalent hydrocarbon group that does not contain an aliphatic unsaturated bond having 6 or more carbon atoms. 6 to 24, preferably 6 to 18. When the number of carbon atoms is less than 6, the volatility of the component (A) is increased, which is not preferable for the reason described later. Examples of the monovalent hydrocarbon group having 6 or more carbon atoms include alkyl groups such as a hexyl group, a heptyl group, an octyl group, a 2-ethylhexyl group, a lauryl group, a myristyl group, a palmityl group, a stearyl group, and a 2-octyldecyl group. A cycloalkyl group such as a cyclohexyl group; an aryl group such as a phenyl group, a tolyl group, a xylyl group, and a naphthyl group; an aralkyl group such as a benzyl group and a phenethyl group, and the like, preferably an alkyl group.

  The component (A) preferably has a volatile content of 20% by mass or less, particularly 0.1 to 18% by mass. When the volatile content of the component (A) exceeds 20% by mass, the component (A) volatilizes during coating, and it becomes difficult to obtain a uniform coating film. In addition, the measurement of a volatile content is the value calculated | required from the mass change before and behind heating an about 2g sample for 3 hours at 105 degreeC.

  The component (A) is used for adjusting the crosslinking density after curing. When a compound having an alkenyl group bonded to two or more silicon atoms in the molecule is used, the crosslink density increases more than necessary, and zipping is likely to occur. On the other hand, since the component (A) has only an alkenyl group bonded to one silicon atom in the molecule, the crosslinking density can be easily adjusted.

  The component (A) is also useful for reducing the viscosity of the composition. For example, even if polydimethylsiloxane having the same viscosity as the component (A) is used instead of the component (A), the viscosity of the final composition is higher than that when the component (A) is used. . Therefore, in order to make the composition using polydimethylsiloxane a viscosity that can be applied, the amount of polydimethylsiloxane must be increased, resulting in the occurrence of zipping and lightening of peeling. Occurs. In addition, olefinic hydrocarbons having an alkenyl group at the terminal can be reduced in viscosity in a small amount, but long-chain olefinic hydrocarbons with low volatility are few and expensive. The component (A) of the present invention can be easily prepared by the following method.

(A) A component is prepared by dehydrochlorination reaction of various chlorosilane and alcohol. For example, an alcohol represented by R ³ —OH is added to a chlorosilane represented by R ¹ R ² _a SiCl _3-a , and further heated with a compound such as triethylamine or urea for capturing generated hydrochloric acid. Thus, the target alkoxysilane of the component (A) can be obtained. (In the formula, R ¹ , R ² , R ³ and a are the same as those shown in the formula (1) of the component (A) described above.)

  As the amount charged in the reaction, an alkoxysilane having no SiCl is obtained by reacting an excess amount of alcohol of 1 mol to 10 mol, preferably 1 mol to 5 mol, with respect to 1 mol of -SiCl. be able to.

（式中、Ｒ³は上記と同じである。） The alkoxysilane as the component (A) is preferably a compound represented by the following formulas (4) to (6).

(Wherein R ³ is the same as above)

（式中、上記Ｃ_fＨ_2f+1（ｆは整数）で表される１価炭化水素基は、直鎖状の分子構造である。）
（Ａ）成分は、一種単独で用いても二種以上を併用してもよい。 Specific examples of the alkoxysilane as the component (A) are shown below, but are not limited thereto.

(In the formula, the monovalent hydrocarbon group represented by C _f H _{2f + 1} (f is an integer) has a linear molecular structure.)
(A) A component may be used individually by 1 type, or may use 2 or more types together.

  As content of (A) component, it is necessary to set it as 20-50 mass parts with respect to a total of 100 mass parts of (A) component and (B) component, Preferably it is 20-45 mass parts. When the content of the component (A) is less than 20 parts by mass, the crosslink density of the cured product becomes high, causing a problem that zipping occurs. When the content of the component (A) exceeds 50 parts by mass, the crosslink density of the cured product is unnecessarily lowered, so that it is difficult to obtain a target heavy peeling effect. Moreover, when content of (A) component remove | deviates from this range, the viscosity of a composition will become high viscosity or too low viscosity, and the problem that it cannot coat on a base material also arises.

[Component (B)]
(B) A component is a component for providing the heavy peeling effect, and the following average compositional formula (2):
(R ⁵ ₃ SiO _1/2 ) _l (R ⁴ R ⁵ ₂ SiO _1/2 ) _m (R ⁴ R ⁵ SiO) _n (R ⁵ ₂ SiO) _p
(R ⁴ SiO _3/2 ) _q (R ⁵ SiO _3/2 ) _r (SiO _4/2 ) _s (2)
(Wherein R ⁴ independently represents an alkenyl group, R ⁵ independently represents an unsubstituted or substituted monovalent hydrocarbon group not containing an aliphatic unsaturated bond, provided that at least 80 mol% of all R ⁵ Is a methyl group, and l, m, n, p, q, r, and s are l ≧ 0, m ≧ 0, n ≧ 0, p ≧ 0, q ≧ 0, r ≧ 0, and s ≧ 0, respectively. (However, m + n + q> 0, q + r + s> 0, and l + m + n + p + q + r + s = 1).
An alkenyl group which is waxy or solid at 25 ° C. and bonded to at least two silicon atoms in one molecule, an R ⁴ SiO _3/2 unit or an R ⁵ SiO _3/2 unit and / or It is a three-dimensional network-like organopolysiloxane resin that essentially contains SiO _4/2 units.

  Here, the term “wax” means a gum shape (raw rubber shape) that exhibits almost no self-fluidity at 25 ° C. of 10,000 Pa · s or more, particularly 100,000 Pa · s or more. In addition, the measurement of a viscosity is the value of the absolute viscosity measured with a B-type rotational viscometer at 25 ° C. (the same applies hereinafter).

In the average composition formula (2), examples of the alkenyl group represented by R ⁴ include the same as those specifically exemplified as R ¹ in the formula (1) of the component (A). A vinyl group is particularly preferable.

The unsubstituted or substituted monovalent hydrocarbon group not containing an aliphatic unsaturated bond represented by R ⁵ is the same as that specifically exemplified as R ² in the formula (1) of the component (A). Although one can be exemplified, at least 80 mole% of the total R ^5, in particular 85 to 95 mol% are methyl groups. When the proportion of methyl groups is less than 80 mol% of the total R ⁵ , the composition is inferior in compatibility with the component (A), so that the composition may become cloudy and a uniform film may not be obtained.

l, m, n, p, q, r and s are numbers satisfying l ≧ 0, m ≧ 0, n ≧ 0, p ≧ 0, q ≧ 0, r ≧ 0 and s ≧ 0, respectively. l is 0 to 0.65, m is 0 to 0.65, n is 0 to 0.5, p is 0 to 0.5, q is 0 to 0.8, r is 0 to 0.8, s is The number is preferably 0 to 0.6.
Further, m + n + q> 0, q + r + s> 0, and 1 + m + n + p + q + r + s = 1. m + n + q is preferably a number from 0.1 to 0.8, in particular from 0.2 to 0.65, and q + r + s is a number from 0.1 to 0.8, in particular from 0.2 to 0.6. preferable.

  In the component (B), the content of the alkenyl group bonded to the silicon atom is preferably in the range of 0.01 to 1 mol, and in the range of 0.05 to 0.5 mol, per 100 g of the component (B). More preferably. When the content of the alkenyl group satisfies the range of 0.01 to 1 mol, the crosslinking reaction proceeds sufficiently, and a cured product with higher hardness can be obtained.

Examples of the organopolysiloxane resin (B) include the following.
(Me ₃ SiO _1/2 ) _{l ′} (ViMe ₂ SiO _1/2 ) _{m ′} (SiO _4/2 ) _{s ′}
(ViMe ₂ SiO _1/2 ) _{m ′} (SiO _4/2 ) _{s ′}
(ViMeSiO) _{n ′} (Me ₂ SiO) _{p ′} (MeSiO _3/2 ) _{r ′}
(ViMe ₂ SiO _1/2 ) _{m ′} (Me ₂ SiO) _{p ′} (ViSiO _3/2 ) _{q ′}
(ViMe ₂ SiO _1/2 ) _{m ′} (Me ₂ SiO) _{p ′} (MeSiO _3/2 ) _{r ′}
(Me ₃ SiO _1/2 ) _{l ′} (ViMe ₂ SiO _1/2 ) _{m ′} (Me ₂ SiO) _{p ′} (MeSiO _3/2 ) _{r ′}
(Me ₃ SiO _1/2 ) _{l ′} (ViMe ₂ SiO _1/2 ) _{m ′} (Me ₂ SiO) _{p ′} (ViMeSiO) _{n ′} (MeSiO _3/2 ) _{r ′}
(In the formula, Me represents a methyl group, Vi represents a vinyl group, and l ′, m ′, n ′, p ′, q ′, r ′, and s ′ represent l ′> 0 and m ′> 0, respectively. , N ′> 0, p ′> 0, q ′> 0, r ′> 0, s ′> 0, provided that l ′, m ′, n ′, p ′, q ′, r ′ and s ′. Is the number satisfying 1. In addition, one molecule has two or more Vis.)

Specifically composed of Me ₃ SiO _1/2 , ViMe ₂ SiO _1/2 and SiO _4/2 units, the molar ratio of the total of Me ₃ SiO _1/2 units and ViMe ₂ SiO _1/2 units to SiO _4/2 units It is more preferable to use an organopolysiloxane resin having an A of 0.6 to 1.3, particularly 0.7 to 1.2. By using such an organopolysiloxane resin, the resulting cured product has a sufficiently high crosslinking density, and a desired heavy peeling effect can be obtained.

The weight average molecular weight of the component (B) is preferably 1,000 to 10,000, more preferably 1,500 to 9,000, and further preferably 2,000 to 8,000.
In addition, the weight average molecular weight in the present invention is an average molecular weight obtained in terms of standard polystyrene by gel permeation chromatography (hereinafter referred to as GPC) analysis (hereinafter the same).
(B) A component may be used individually by 1 type, or may use 2 or more types together.

  As content of (B) component, it is necessary to set it as 80-50 mass parts with respect to a total of 100 mass parts of (A) component and (B) component, Preferably it is 80-55 mass parts. When content of (B) component exceeds 80 mass parts, the crosslinking density of hardened | cured material will become high and the problem that a zipping generate | occur | produces will arise. When the content of the component (B) is less than 50 parts by mass, the crosslinking density of the cured product is unnecessarily lowered, and it is difficult to obtain a target heavy peeling effect.

[Component (C)]
The component (C) serves as a crosslinking agent that reacts and crosslinks with the alkenyl group contained in the component (A) and the component (B) by a hydrosilylation reaction, and the following average composition formula (3):
R ⁶ _b H _c SiO _{(4-bc) / 2} (3)
(Wherein R ⁶ independently represents an unsubstituted or substituted monovalent hydrocarbon group not containing an aliphatic unsaturated bond, and b and c are 0.7 ≦ b ≦ 2.1, 0.001 ≦ c. ≦ 1.0 and a positive number satisfying 0.8 ≦ b + c ≦ 3.0.)
And an organohydrogenpolysiloxane having at least two hydrogen atoms bonded to a silicon atom in one molecule.

In the average composition formula (3), an unsubstituted or substituted monovalent hydrocarbon group not containing an aliphatic unsaturated bond represented by R ⁶ is R ² in the formula (1) of the component (A). Although specifically exemplified ones and can be exemplified the same ones as at least 50 mole% of the total R ^6, and typically from 60 to 100 mol% are methyl groups. When the proportion of methyl groups is less than 50 mol% of the total R ⁶ , the compatibility with the component (A) and the component (B) is inferior, and the problem of white turbidity or phase separation of the composition occurs. There is.

  b is 0.7 ≦ b ≦ 2.1, preferably 1.0 ≦ b ≦ 2.0, c is 0.001 ≦ c ≦ 1.0, preferably 0.01 ≦ c ≦ 0.98, and b + c is It is a positive number satisfying 0.8 ≦ b + c ≦ 3.0, preferably 1.3 ≦ b + c ≦ 2.5.

  In the component (C), the content of hydrogen atoms bonded to the silicon atom is preferably in the range of 0.001 to 0.02 mol, and 0.002 to 0.017 mol per gram of the component (C). More preferably, it is the range.

  The hydrogen atom bonded to the silicon atom contained in at least two molecules (usually 2 to 200, preferably 2 to 100) in one molecule may be located at either the molecular chain end or in the middle of the molecular chain. Or may be located in both of them. The molecular structure of the organohydrogenpolysiloxane may be any of linear, cyclic, branched, and three-dimensional network structures, but the number of silicon atoms in one molecule (or the degree of polymerization) is Usually, about 2 to 300, preferably about 3 to 200 are desirable.

  The viscosity of component (C) at 25 ° C. is 1,000 mPa · s or less, usually 0.5 to 1,000 mPa · s, preferably 2 to 200 mPa · s. If the viscosity is too high, the entire composition becomes too viscous, which may cause a problem that it cannot be applied well to the substrate.

  Examples of the organohydrogenpolysiloxane of component (C) include methylhydrogensiloxane / dimethylsiloxane cyclic copolymer, both terminal trimethylsiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer, both terminal dimethylhydrogensiloxy. Blocked dimethylpolysiloxane, both ends dimethylhydrogensiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer, both ends trimethylsiloxy group-blocked methylhydrogensiloxane / diphenylsiloxane copolymer, both ends trimethylsiloxy group-blocked methylhydro Gensiloxane / diphenylsiloxane / dimethylsiloxane copolymer, trimethylsiloxy group-blocked methylhydrogensiloxane / methylpheny Siloxane / dimethylsiloxane copolymer, both ends dimethylhydrogensiloxy group-capped methylhydrogensiloxane / dimethylsiloxane / diphenylsiloxane copolymer, both ends dimethylhydrogensiloxy group-capped methylhydrogensiloxane / dimethylsiloxane / methylphenylsiloxane A polymer etc. are mentioned.

（式中、ｄ１は１〜１００の整数、ｅ１は２〜１００の整数である。）
で表される環状シロキサン、

（式中、ｄ１は１〜１００の整数、ｄ２は１〜２００の整数、ｄ３は０〜１００の整数、ｅ１は２〜１００の整数、ｅ２は２〜２００の整数、ｅ３は１〜１００の整数である。）
で表される直鎖シロキサン等が例示される。 As an example of more specific component (C),

(In the formula, d1 is an integer of 1 to 100, and e1 is an integer of 2 to 100.)
A cyclic siloxane represented by

(In the formula, d1 is an integer of 1 to 100, d2 is an integer of 1 to 200, d3 is an integer of 0 to 100, e1 is an integer of 2 to 100, e2 is an integer of 2 to 200, and e3 is 1 to 100. (It is an integer.)
The linear siloxane etc. which are represented by these are illustrated.

  (C) A component may be used individually by 1 type, or may use 2 or more types together.

  The blending amount of the component (C) is such that the number of hydrogen atoms bonded to the silicon atom in the component (C) is 0.5 with respect to the total alkenyl groups in the component (A) and the component (B), from the balance of crosslinking. The amount is controlled to ˜5 times mol, preferably 0.7 to 4 times mol, more preferably 1 to 3 times mol. If the blending amount does not satisfy the amount of 0.5 to 5 moles, the balance of crosslinking may be inappropriate.

[(D) component]
The (D) component platinum group metal-based catalyst is a catalyst for promoting the addition reaction of the (A) component and the (B) component and the (C) component, and is known to those skilled in the art as promoting the so-called hydrosilylation reaction. Any known one can be used. Examples of such platinum group metal-based catalysts include platinum-based, palladium-based, rhodium-based, and ruthenium-based catalysts. Of these, platinum-based catalysts are particularly preferably used. Examples of the platinum-based catalyst include chloroplatinic acid, alcohol solution or aldehyde solution of chloroplatinic acid, complexes of chloroplatinic acid with various olefins or vinyl siloxane, complexes of platinum with various olefins or vinyl siloxane, and the like. .

  The compounding amount of the component (D) may be a so-called effective amount as a catalyst. Specifically, from the viewpoint of obtaining an excellent cured film and economically, the component (A), the component (B) and the component (C) It is 0.1 to 1,000 ppm, more preferably 1 to 500 ppm in terms of the mass of the platinum group metal with respect to the total mass of the components.

[Other ingredients]
In addition to the components (A) to (D), other optional components can be blended in the composition of the present invention. Specific examples thereof include the following. Each of these other components may be used alone or in combination of two or more.

-Alkenyl group-containing compound other than (A) component and (B) component In addition to the (A) component and the (B) component, the composition of the present invention includes an alkenyl group-containing compound that undergoes addition reaction with the (C) component. You may mix | blend. As such an alkenyl group-containing compound other than the component (A) and the component (B), those which are involved in the formation of a cured product are preferable, and have an alkenyl group bonded to at least one silicon atom per molecule (A And organopolysiloxanes other than the component (B) and the component (B). The molecular structure may be any of linear, cyclic, branched, three-dimensional network, etc. The compounding amount of the component is 20 parts by mass or less, preferably 10 parts by mass or less, and (A) component, (B) with respect to 100 parts by mass in total of the components (A), (B) and (C). The hydrogen atom bonded to silicon in the component (C) is 0.5 to 5 times mol, preferably 0.7 to 4 times mol, more preferably 1 to 3 times the component and all alkenyl groups in the component. It is desirable that the amount be molar. When the blending amount exceeds 20 parts by mass, or when the amount to be 0.5 to 5 times mol is not satisfied, the balance of crosslinking may be inappropriate.

-Addition reaction control agent In order to ensure pot life, an addition reaction control agent can be mix | blended with the composition of this invention. The addition reaction control agent is not particularly limited as long as it is a compound having a curing inhibitory effect on the platinum group metal catalyst of the component (D), and conventionally known ones can be used. Specific examples thereof include phosphorus-containing compounds such as triphenylphosphine; nitrogen-containing compounds such as tributylamine, tetramethylethylenediamine and benzotriazole; sulfur-containing compounds; acetylene alcohols (for example, 1-ethynylcyclohexanol, 3,5- Acetylene compounds such as dimethyl-1-hexyn-3-ol); compounds containing two or more alkenyl groups; hydroperoxy compounds; and maleic acid derivatives.
The degree of the curing inhibitory effect of the addition reaction control agent varies depending on the chemical structure of the addition reaction control agent. Therefore, it is preferable to adjust the addition amount to an optimum amount for each of the addition reaction control agents to be used. By adding an optimal amount of addition reaction control agent, the composition has excellent long-term storage stability at room temperature and heat curability.

Other optional components Further, as necessary, as long as they do not interfere with the effects of the present invention, other known optional antioxidants, pigments, stabilizers, antistatic agents, antifoaming agents, adhesion improvers, An inorganic filler such as a thickener and silica can be blended.

In the preparation of the heavy release composition for release sheet of the present invention, the method of adding the components (A) to (C) and the optional components in advance and then adding the component (D) immediately before use is in terms of pot life. desirable.
Since the heavy release composition for release sheet of the present invention does not require a solvent, it can be a solvent-free heavy release composition.

[viscosity]
The viscosity at 25 ° C. of the heavy release composition for release sheet of the present invention is preferably 50 to 2,000 mPa · s, particularly 50 to 1,000 mPa · s. If the viscosity is out of this range, problems such as inability to apply when forming a cured film on the substrate and a uniform film may occur. In addition, in order to make the viscosity of the heavy release composition for release sheets of this invention into this range, (A) component is 20-50 with respect to a total of 100 mass parts of (A) component and (B) component. Part (B) is 80 to 50 parts by mass, and (C) is hydrogen bonded to silicon atoms in component (C) with respect to all alkenyl groups in components (A) and (B). It can achieve by mix | blending the quantity from which an atom becomes 0.5-5 times mole. Furthermore, the viscosity at 25 ° C. of the component (C) is 1,000 mPa · s or less, usually 0.5 to 1,000 mPa · s, preferably 2 to 200 mPa · s.

[Coated product (release sheet)]
The release sheet of the present invention has a cured film of the above-mentioned heavy release composition for release sheet on one side or both sides of the sheet-like substrate surface.

As a method for preparing the release sheet, a cured film can be formed by applying the heated release composition for release sheet on one or both sides of the surface of the sheet-like base material and heating.
For example, a heavy release composition for a release sheet as it is, coating with a comma coater, lip coater, roll coater, die coater, knife coater, blade coater, rod coater, kiss coater, gravure coater, wire bar coater, etc., screen coating, dip coating, using a coating method such as cast-coated paper, 0.01 to 100 g / m ² on one or both sides on the sheet-like substrate such as a film, in particular 0.1 to 10 g / m ² After coating, a cured film can be formed on the substrate by heating at 50 to 200 ° C., particularly 80 to 180 ° C. for 1 to 120 seconds, particularly 3 to 60 seconds. When the release layers are formed on both surfaces of the substrate, it is preferable to perform a cured film forming operation for each surface of the substrate.

  In addition, in this invention, in addition to what a sheet-like base material is paper, what was formed with well-known various films etc. is included with a peeling sheet. Examples of substrates include various types of coated paper such as polyethylene laminated paper, glassine paper, fine paper, kraft paper, clay coated paper, synthetic paper such as YUPO, polyethylene film, polypropylene film such as CPP and OPP, polyethylene terephthalate film, etc. Polyester film, polyamide film, polyimide film, polylactic acid film, polyphenol film, polycarbonate film and the like. It is also possible to use process paper for manufacturing artificial leather, ceramic sheets, double-sided separators and the like as a base material. In order to improve the adhesion between the substrate and the release layer, the substrate surface may be subjected to corona treatment, etching treatment, primer treatment or plasma treatment. In addition, although it does not restrict | limit especially as thickness of a sheet-like base material, It is preferable that it is 10-500 micrometers.

In the present invention, the release sheet prepared by applying 0.9 to 1.2 g / m ² of the above heavy release composition on a polyethylene laminated paper substrate and then heating at 140 ° C. for 30 seconds is the FINAT test method. The peel force measured by the above (a 25 mm wide acrylic adhesive tape TESA-7475 (trade name, manufactured by Tesa Tape. Inc) was applied to the cured film of the above heavy release composition and a load of 70 g / m ^{2 in} a dryer at 25 ° C. And the TESA-7475 tape is peeled off at an angle of 180 ° using a tensile tester at a peeling speed of 0.3 m / min) and is 5 to 25 N / 25 mm. It is preferably 5 to 20 N / 25 mm, more preferably 5 to 15 N / 25 mm. By setting it as this peeling force, it can be used as a peeling material with a high heavy peeling effect. Another characteristic of the release sheet of the present invention is that there is little change in peel force over time (difference between initial peel force and time peel force measured by the method described later). In the present invention, the “heavy stripping composition” refers to a material having the above peeling force by the above measuring method.
[Initial peel force measurement method]
After the release sheet obtained by the above curing method is stored at 25 ° C. for 24 hours, the peel force measured by the FINAT test method as described above is defined as the initial peel force. In this invention, it is preferable that this peeling force is 5-25N / 25mm, especially 5-15N / 25mm.
[Method of measuring peel strength over time]
After the release sheet obtained by the above curing method is stored at 50 ° C. for 7 days, the peel force measured by the FINAT test method as described above is defined as the peel force with time. In the present invention, the peel force is preferably 5 to 25 N / 25 mm, particularly 5 to 15 N / 25 mm, and particularly preferably has a peel force of 85% or more with respect to the initial peel force.

  EXAMPLES Hereinafter, although a preparation example, an Example, and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example. In the following examples, Me represents a methyl group, and Vi represents a vinyl group. Moreover,% shows the mass%, a viscosity shows the value in 25 degreeC measured with the rotational viscometer, and a volatile matter shows the value measured by the method shown below.

[Measurement method of volatile matter]
About 2 g of sample is taken into a 50 ml beaker and weighed accurately (Ag). After 3 hours in a dryer at 105 ° C., weigh the remaining sample accurately (Bg). The volatile content is calculated from the following formula.
Volatile content (%) = (A−B) / A × 100

[Preparation Example 1] Preparation of platinum catalyst A reaction product of hexachloroplatinic acid and 1,3-divinyltetramethyldisiloxane has a viscosity of 400 mPa · s and an average molecular formula so that the platinum content is 0.5 mass%. : Diluted with a linear dimethylpolysiloxane of ViMe ₂ SiO (SiMe ₂ O) ₁₅₀ SiMe ₂ Vi to prepare a platinum catalyst (D) used in this example and comparative examples.

[Preparation Example 2] Preparation of component (A-1) To a 500 mL flask equipped with a stirrer, a condenser, a dropping funnel and a thermometer, 72.3 g (0.6 mol) of dimethylvinylchlorosilane and 113 g of toluene were added, and oil was added. Heated to 60 ° C. using a bath. 43.2 g (0.72 mol) of urea was added thereto, and 179 g (0.6 mol) of 2-octyldodecanol (product name: Calcoal 200GD, manufactured by Kao Corporation) was further added dropwise. After completion of dropping, the mixture was stirred at 90 to 95 ° C. for 9 hours. After cooling to room temperature, the urea layer capturing the hydrochloric acid was separated, and 0.024 g (0.41 mmol) of propylene oxide was added to the remaining organic layer, followed by neutralization by stirring at room temperature for 2 hours. Then, concentration under reduced pressure and filtration were performed to obtain a pale yellow reaction product (A-1) (volatile content: 0.5%).

As a result of analyzing the reaction product by NMR, it was found that this reaction product was a compound represented by the following structural formula.

[Preparation Example 3] Preparation of component (A-2) To a 1 L flask equipped with a stirrer, a condenser, a dropping funnel and a thermometer, 98.7 g (0.7 mol) of methylvinyldichlorosilane and 181 g of toluene were added, Heated to 60 ° C. using an oil bath. 100.8 g (1.68 mol) of urea was added thereto, and 218.4 g (1.68 mol) of 1-octanol was further added dropwise. After completion of dropping, the mixture was stirred at 90 to 95 ° C. for 6 hours. After cooling to room temperature, the urea layer capturing the hydrochloric acid was separated, and 0.026 g (0.44 mmol) of propylene oxide was added to the remaining organic layer, followed by neutralization by stirring at room temperature for 2 hours. Then, concentration under reduced pressure and filtration were performed to obtain a pale yellow reaction product (A-2) (volatile content: 4.1%).

As a result of analyzing the reaction product by NMR, it was found that this reaction product was a compound represented by the following structural formula.

[Preparation Example 4] Preparation of component (A-3) To a 1 L flask equipped with a stirrer, a condenser, a dropping funnel and a thermometer, 70.5 g (0.5 mol) of methylvinyldichlorosilane and 134 g of toluene were added, Heated to 60 ° C. using an oil bath. Urea 72g (1.2mol) was added there, and also 2-ethylhexanol 169g (1.3mol) was dripped. After completion of dropping, the mixture was stirred at 90 to 95 ° C. for 4 hours. After cooling to room temperature, the urea layer capturing the hydrochloric acid was separated, and 0.36 g (6.3 mmol) of propylene oxide was added to the remaining organic layer, followed by neutralization by stirring at room temperature for 2 hours. Then, concentration under reduced pressure and filtration were performed to obtain a yellow reaction product (A-3) (volatile content: 16.0%).

As a result of analyzing the reaction product by NMR, it was found that this reaction product was a compound represented by the following structural formula.

[Example 1]
(1) and alkoxysilane obtained in Preparation Example 1 (A-1), Me 3 SiO 1/2, ViMe 2 SiO 1/2, and is composed of SiO _4/2 units, with respect to SiO _4/2 A 50% xylene solution of an organopolysiloxane resin (B) having a molar ratio of Me ₃ SiO _1/2 and ViMe ₂ SiO _1/2 of 0.8 and a vinyl group content to the solid content of 0.085 mol / 100 g; Were mixed at a mass ratio of 20:50 in terms of active ingredients. To 120 parts by mass of this liquid, 6.2 parts by mass of methyl hydrogen siloxane (C-1) having an SiH group only in the side chain represented by the average molecular formula: Me ₃ SiO (SiHMeO) ₅₂ SiMe ₃ was mixed. Xylene was removed under reduced pressure of 20 mmHg or less at ° C to obtain a transparent liquid (molar ratio of total SiH groups to total alkenyl groups in the composition, that is, H / Vi was 1.2).
(2) 0.2 parts by mass of 1-ethynylcyclohexanol (E) as an addition reaction control agent and 2.0 parts by mass of the platinum catalyst (D) obtained in Preparation Example 1 are uniformly added to 100 parts by mass of this liquid. To obtain a transparent heavy release composition having a viscosity of 490 mPa · s.

[Examples 2-8, Comparative Examples 1-8]
In the same manner as in Example 1, after mixing the (A) component, the (B) component, the (C) component, and the (F) component used in the comparative example, the components in the (B) component were distilled off under reduced pressure. Xylene was removed, and then the component (E), which is an addition reaction control agent, and the platinum catalyst (D) obtained in Preparation Example 1 were mixed, and the heavy peeling shown in Examples 2-8 and Comparative Examples 1-6 A composition was obtained.
In addition, since the component (F-4) is volatile, xylene is removed by distillation under reduced pressure after mixing the component (B) and the component (C), and then the component (F-4) and (E) The component and the component (D) were mixed to obtain a heavy release composition shown in Comparative Examples 7 and 8.
The compounds used in the components (A) to (F) are as shown below, and the blending amounts (unit: parts by mass) are shown in Tables 1 to 4 below. In addition, (A) component or (F) component content rate in a table | surface is (A) component or (F) component (mass) with respect to a total of 100 mass parts of (A) component or (F) component, and (B) component. Part) content (%).

(A-1) Alkoxysilane obtained in Preparation Example 2 (A-2) Alkoxysilane obtained in Preparation Example 3 (A-3) Alkoxysilane obtained in Preparation Example 4 (B) Me ₃ SiO _{1 / 2} , ViMe ₂ SiO _1/2 , and SiO _4/2 units, the molar ratio of Me ₃ SiO _1/2 and ViMe ₂ SiO _1/2 to SiO _4/2 is 0.8, and the solid content Organopolysiloxane resin with a vinyl group content of 0.085 mol / 100 g (weight average molecular weight: 5,800)
(C-1) Average molecular formula: Me ₃ SiO (SiHMeO) ₅₂ Methyl hydrogen polysiloxane represented by SiMe ₃ (C-2) Average molecular formula: Me ₃ SiO (SiHMeO) ₄₅ (SiMe ₂ O) _{17 In} SiMe ₃ Methyl hydrogen polysiloxane (C-3) average molecular formula: HMe ₂ SiO (SiMe ₂ O) ₈ Platinum catalyst obtained in methyl hydrogen polysiloxane (D) Preparation Example 1 represented by SiMe ₂ H ( E) 1-Ethynylcyclohexanol (addition reaction control agent)
(F-1) Average molecular formula: ViMe ₂ SiO (SiMe ₂ O) ₈ Organopolysiloxane represented by SiMe ₂ Vi (viscosity: 8.2 mPa · s, volatile content: 7.4%)
(F-2) Average molecular formula: ViMe ₂ SiO (SiMe ₂ O) ₆₆ Organopolysiloxane represented by SiMe ₂ Vi (viscosity: 100 mPa · s, volatile content: 1.4%)
(F-3) Average molecular formula: ViMe ₂ SiO (SiMe ₂ O) ₁₄ Organopolysiloxane represented by SiMe ₃ (viscosity: 6.0 mPa · s, volatile content: 10.9%)
(F-4) 1-hexadecene (viscosity: 3.8 mPa · s, volatile content: 100%)

About each composition of Examples 1-8 obtained as mentioned above and Comparative Examples 1-8, the viscosity in 25 degreeC was measured with a B-type rotational viscometer, and also a peeling sheet was produced with the method shown below. Then, the peeling force was evaluated by the method shown below. The obtained results are shown in Tables 1 to 4. In the table, “Z” indicates zipping. Peeling force reduction rate [%] is a value determined from time-dependent peeling force / initial peeling force × 100.
Moreover, the peeling force measurement result at the time of zipping is shown in FIG. 1, and the normal peeling force measurement result without zipping is shown in FIG. As shown in FIG. 1, when zipping, the peeling force is not stable, and it is difficult to accurately measure the peeling force.

[Method for producing release sheet]
The heavy release composition obtained above was applied to a polyethylene laminated paper substrate with a gravure coater so as to be 0.9 to 1.2 g / m ² and heated in a hot air dryer at 140 ° C. for 30 seconds. This was used as a release sheet for the following measurements.

[Measurement method of initial peel force]
After the release sheet obtained above was stored at 25 ° C. for 24 hours, a 25 mm wide acrylic pressure-sensitive adhesive tape TESA-7475 (trade name, manufactured by Tesa Tape. Inc) was bonded to a 70 g / 25 ° C. dryer. Samples stored for 24 hours with a load of m ² were used. After air cooling for about 30 minutes, the sample TESA-7475 tape is peeled off at 0.3 m / min at an angle of 180 ° using a tensile tester (DSC-500 type tester manufactured by Shimadzu Corporation) and peeled off. Was used as an initial peel force (N / 25 mm).

[Method of measuring peel force with time]
After the release sheet obtained above was stored at 50 ° C. for 7 days, a 25 mm wide acrylic adhesive tape TESA-7475 (trade name, manufactured by Tesa Tape. Inc.) was bonded to a 70 g / 25 ° C. dryer. Samples stored for 24 hours with a load of m ² were used. After air cooling for about 30 minutes, the sample TESA-7475 tape is peeled off at 0.3 m / min at an angle of 180 ° using a tensile tester (DSC-500 type tester manufactured by Shimadzu Corporation) and peeled off. The force required for the measurement was measured to determine the peel force after aging (N / 25 mm).

  From the above results, the heavy release composition of the present invention (Examples 1 to 8) has high fluidity at 25 ° C., and the release sheet has a high release force of 10 N / 25 mm or more in the initial stage, Moreover, it has a peel strength of 85% or more with respect to the initial stage even after aging. Further, there is no occurrence of zipping at the time of peeling at the initial stage and after the passage of time. Therefore, the heavy release composition of the present invention is useful as a material for a release sheet for heavy release.

  On the other hand, when the amount of component (A) was reduced (Comparative Example 1), the viscosity exceeded 2,000 mPa · s, and it was difficult to apply the coating. Conversely, when the amount of component (A) was increased (Comparative Example 2), the ratio of organic groups increased more than necessary, causing zipping. Even when a short-chain polydimethylsiloxane having vinyl groups at both ends was used (Comparative Example 3), the crosslinking density became too high and zipping occurred. Furthermore, when long-chain polydimethylsiloxane having vinyl groups at both ends is used (Comparative Example 4), when short-chain polydimethylsiloxane having vinyl groups at one end is used (Comparative Examples 5 and 6). As a result, the crosslink density was reduced and the proportion of siloxane sites was increased, resulting in lighter peeling. Moreover, when 1-hexadecene with high volatility was used (Comparative Examples 7 and 8), since it volatilized during coating, a uniform coating film could not be obtained. From the above results, it is considered that the compositions shown in Comparative Examples 1 to 8 are unsuitable for the above uses.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.

Claims (6)

(A) The following average composition formula (1):
R ¹ R ² _a Si (OR ³ ) _3-a (1)
(Wherein R ¹ independently represents an alkenyl group, R ² independently represents an unsubstituted or substituted monovalent hydrocarbon group not containing an aliphatic unsaturated bond, and R ³ independently represents 6 or more carbon atoms. A linear, branched or cyclic, unsubstituted or substituted monovalent hydrocarbon group that does not contain an aliphatic unsaturated bond, and a is an integer that satisfies 0 ≦ a ≦ 2.)
An alkoxysilane having an alkenyl group bonded to one silicon atom in the molecule: 20 to 50 parts by mass
(B) The following average composition formula (2):
(R ⁵ ₃ SiO _1/2 ) _l (R ⁴ R ⁵ ₂ SiO _1/2 ) _m (R ⁴ R ⁵ SiO) _n (R ⁵ ₂ SiO) _p
(R ⁴ SiO _3/2 ) _q (R ⁵ SiO _3/2 ) _r (SiO _4/2 ) _s (2)
(Wherein R ⁴ independently represents an alkenyl group, R ⁵ independently represents an unsubstituted or substituted monovalent hydrocarbon group not containing an aliphatic unsaturated bond, provided that at least 80 mol% of all R ⁵ Is a methyl group, and l, m, n, p, q, r, and s are l ≧ 0, m ≧ 0, n ≧ 0, p ≧ 0, q ≧ 0, r ≧ 0, and s ≧ 0, respectively. (However, m + n + q> 0, q + r + s> 0, and l + m + n + p + q + r + s = 1).
A three-dimensional network-like organopolysiloxane resin having an alkenyl group bonded to at least two silicon atoms in one molecule, which is waxy or solid at 25 ° C .: 80 to 50 parts by mass
(However, the sum of component (A) and component (B) is 100 parts by mass.)
(C) The following average composition formula (3):
R ⁶ _b H _c SiO _{(4-bc) / 2} (3)
(Wherein R ⁶ independently represents an unsubstituted or substituted monovalent hydrocarbon group not containing an aliphatic unsaturated bond, and b and c are 0.7 ≦ b ≦ 2.1, 0.001 ≦ c. ≦ 1.0 and a positive number satisfying 0.8 ≦ b + c ≦ 3.0.)
And an organohydrogenpolysiloxane having at least two hydrogen atoms bonded to a silicon atom in one molecule: silicon in component (C) with respect to all alkenyl groups in component (A) and component (B) The amount of hydrogen atoms bonded to the atoms is 0.5-5 moles,
(D) Platinum group metal catalyst: Heavy release composition for release sheet containing an effective amount. The alkoxysilane having an alkenyl group bonded to one silicon atom in the molecule of the component (A) is represented by the following formulas (4) to (6):

(In the formula, R ³ independently represents a linear, branched or cyclic unsubstituted or substituted monovalent hydrocarbon group not containing an aliphatic unsaturated bond having 6 or more carbon atoms.)
The heavy release composition for release sheets according to claim 1, which is selected from the compounds represented by formula (1).   The heavy release composition for release sheets according to claim 1 or 2, wherein the volatile content of the alkoxysilane having an alkenyl group bonded to one silicon atom in the molecule of the component (A) is 20% by mass or less.   The heavy release composition for release sheets according to any one of claims 1 to 3, wherein the viscosity at 25 ° C is 50 to 2,000 mPa · s.   The release sheet which has a cured film of the heavy peeling composition for release sheets of any one of Claims 1-4 on the single side | surface or both surfaces of a sheet-like base material surface.   The release sheet according to claim 5, wherein a Tessa7475 tape is attached to the cured film, and the peel force measured at an angle of 180 ° and a peel speed of 0.3 m / min is 5 to 25 N / 25 mm.

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