JP6642740B2 - Heavy release composition for release sheet and release sheet - Google Patents

Description

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

  2. Description of the Related Art Conventionally, in order to prevent adhesion and adhesion between a substrate such as paper and plastic and an adhesive material, a cured film of an organopolysiloxane composition is formed on the surface of the substrate to impart release properties. As a method for forming an organopolysiloxane cured film on the above-mentioned substrate surface, the method of forming a releasable film by an addition reaction is excellent in curability, and can respond to various demands for release characteristics from low-speed release to high-speed release. Therefore, it is widely used.

  The release film forming method by this addition reaction includes a type in which the organopolysiloxane composition is dissolved in an organic solvent, a type in which the composition is dispersed in water using an emulsifier to form an emulsion, and a non-solvent type comprising only an organopolysiloxane. However, the solvent type has a drawback that it may be harmful to the human body and the environment, and therefore the switch from the solvent type to the non-solvent type is proceeding from the viewpoint of safety.

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

  However, the alkenyl group-containing MQ resin is often a resinous or high-viscosity compound, and when added in large amounts, it cannot be used unless diluted with an organic solvent. If a small amount is added, 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 that there is no need to change the peeling force over time.

  On the other hand, when the tape is peeled from the heavily peeled sheet, peeling sound (zipping) may be a problem. Although the detailed mechanism of the zipping has not been clarified in many parts, zipping tends to occur particularly in a heavy release sheet having a high crosslinking density. Therefore, suppression of zipping is also an important issue when developing a heavy peeling sheet.

  Japanese Patent Publication No. 5-53183 (Patent Document 1) discloses that an alkenyl group-containing MQ resin and an alkenyl group-free MQ resin are used in combination in an organopolysiloxane composition for release paper. , But the heavy peeling effect is insufficient.

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

  Japanese Patent Publication No. 6-085882 (Patent Document 3) is an adhesive organopolysiloxane protective coating having a partially dehydrated condensation product of a curable silicone rubber, an organopolysiloxane containing hydroxyl groups at both ends and a silicone resin containing MQ units. . Since the silicone rubber and the silicone resin are high in viscosity or solid, a solvent is required.

  Japanese Patent Application Laid-Open No. H10-110156 (Patent Document 4) is a technique relating to an organopolysiloxane-based pressure-sensitive adhesive whose main component is a mixture or partial condensate of a raw vinyl rubber and an MQ resin. This method requires a solvent because of the use of silicone rubber, and does not mention the effect as a heavy release composition for release paper.

  JP 2010-37557 A (Patent Document 5) discloses that (a1) the molar ratio of the M unit to the Q unit is 0.6 to 1.0, and the content of the hydroxyl group or the alkoxy group is 0.3 to 2.0. An organopolysiloxane obtained by subjecting 100 parts by mass of an MQ type resin in the range of 0% by mass to (a2) 20 to 150 parts by mass of a chain polydiorganosiloxane having an average degree of polymerization of 100 to 1,000 and having a hydroxyl group or an alkoxy group, by condensation reaction. It is a release modifier composed of a resin-organopolysiloxane condensation reaction product. According to Patent Document 6, the peeling force in Examples is increased only 1.4 times to 2.2 times at a low speed (0.3 m / min) as compared with a comparative example in which no condensation reactant is added. No heavy separation effect has been obtained. This has a low content of the hydroxyl group or alkoxy group of (a1) used in the range of 0.3 to 2.0% by mass, has few reaction points with (a2), and has a crosslinked structure by sufficient condensation. It is presumed that it is not.

  Japanese Patent Application Laid-Open No. Hei 5-329184 (Patent Document 6) is a patent for the purpose of suppressing zipping when peeling a tape from a diaper, and includes a release layer in which an MQ resin is mixed with a silicone release agent, and an AB type. It is composed of a pressure-sensitive adhesive layer in which a block copolymer and a tackifier are mixed. According to this patent, although zipping can be suppressed, a solvent is used for the release layer, and only evaluation as an adhesive is performed, and no mention is made of release characteristics.

  JP-A-6-228501 (Patent Document 7) discloses a method of increasing the peeling force of a pressure-sensitive adhesive without using an alkenyl group-containing MQ resin. This is a composition in which the crosslink density is adjusted by using a higher alkenyl group in the crosslink site, but no mention is made of zipping, and the heavy release effect is insufficient because no alkenyl group-containing MQ resin is used. .

  JP-A-7-188562 (Patent Document 8) is a heavy release composition using an alkenyl group-containing MQ resin, an α, ω-diolefin, and an organohydrogenpolysiloxane. Although the use of an alkenyl group-containing MQ resin and an α, ω-diolefin has a very high peeling force, no problem with zipping has been raised, and means for solving this problem have been suggested. Absent.

Japanese Patent Publication No. 5-53183 Japanese Patent No. 2750896 Japanese Patent Publication No. 6-065882 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 has an excellent heavy peeling effect, suppresses zipping at the time of peeling, and further has a small decrease in peeling force over time after curing, and a heavy release composition for a release sheet, and its curing. An object is to provide a release sheet having a film formed thereon.

  The present inventors have conducted intensive studies in order to achieve the above object. As a result, (A) one-terminal-reactive organopolysiloxane having one alkenyl group at the terminal, and (B) at least two organopolysiloxanes per molecule. A composition comprising: an organopolysiloxane having two alkenyl groups; (C) an organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms in one molecule; and (D) a platinum group metal catalyst, The amount of the component (A) relative to the total amount of the components (A) and (B) is within a specific range, and the component (B) is directly mixed with the organopolysiloxane resin (B-1) having a three-dimensional network structure. Organohydride having a hydrogen atom bonded to a silicon atom in the side chain in the component (C) in a specific mass ratio of the chain or branched organopolysiloxane (B-2). Genpolysiloxane (C-1) and organohydrogenpolysiloxane (C-2) having a hydrogen atom bonded to a silicon atom at a terminal and not having a side chain at a specific mass ratio, The inventors have found that the obtained composition has an excellent heavy peeling effect, suppresses zipping at the time of peeling, and has little decrease in peeling force with time after curing, and has accomplished the present invention.

（式中、Ｒ¹はアルケニル基を表し、Ｒ²は独立にアルケニル基を含まない非置換又は置換の１価炭化水素基を表し、ａは１≦ａ≦２００を満たす整数である。）
で表される、末端に１個のアルケニル基を有する片末端反応性オルガノポリシロキサン：（Ａ）成分と（Ｂ）成分の合計量に対して（Ａ）成分が１０〜３５質量部
（Ｂ）下記平均組成式（２）：
Ｒ³ _bＳｉＯ_(4-b)/2・・・（２）
（式中、Ｒ³は独立に非置換又は置換の１価炭化水素基であり、ｂは０＜ｂ≦３を満たす正数である。）で表される、１分子中に少なくとも２個のアルケニル基を有するオルガノポリシロキサン：（Ａ）成分と（Ｂ）成分との合計１００質量部に対して（Ｂ）成分が６５〜９０質量部
（Ｃ）下記平均組成式（３）：
Ｒ⁴ _cＨ_dＳｉＯ_(4-c-d)/2・・・（３）
（式中、Ｒ⁴は独立にアルケニル基を含まない非置換又は置換の１価炭化水素基であり、ｃ及びｄは、０．７≦ｃ≦２．１、０．００１≦ｄ≦１．０、かつ０．８≦ｃ＋ｄ≦３．０を満たす正数である。）
で表される、ケイ素原子に結合した水素原子を１分子中に少なくとも２個有するオルガノハイドロジェンポリシロキサン：（Ａ）成分及び（Ｂ）成分中の全アルケニル基に対して（Ｃ）成分中のケイ素原子に結合した水素原子が０．５〜５．０倍モルとなる量、
（Ｄ）白金族金属系触媒：有効量
を含む剥離シート用重剥離組成物であって、
上記（Ｂ）成分が、１分子中に少なくとも２個のアルケニル基を有する、２５℃において蝋状もしくは固体である、三次元網状構造を有するオルガノポリシロキサン樹脂（Ｂ−１）と、２５℃において液状である、末端に少なくとも２個のアルケニル基を有する直鎖状又は分岐鎖状のオルガノポリシロキサン（Ｂ−２）の組合せであり、（Ｂ−１）成分と（Ｂ−２）成分との質量比（Ｂ−２）／（Ｂ−１）が０．１〜０．５であり、かつ、
上記（Ｃ）成分が、ケイ素原子に結合した水素原子を側鎖に有するオルガノハイドロジェンポリシロキサン（Ｃ−１）と、ケイ素原子に結合した水素原子を末端に有しかつ側鎖には有しないオルガノハイドロジェンポリシロキサン（Ｃ−２）の組合せであり、（Ｃ−１）成分と（Ｃ−２）成分の質量比（Ｃ−２）／（Ｃ−１）が１〜５である剥離シート用重剥離組成物。
［２］．上記（Ｂ−１）成分が、下記平均組成式（４）：
（Ｒ⁶ ₃ＳｉＯ_1/2）_e（Ｒ⁵Ｒ⁶ ₂ＳｉＯ_1/2）_f（Ｒ⁵Ｒ⁶ＳｉＯ）_g（Ｒ⁶ ₂ＳｉＯ）_h（Ｒ⁵ＳｉＯ_3/2）_i（Ｒ⁶ＳｉＯ_3/2）_j（ＳｉＯ_4/2）_k・・・（４）
（式中、Ｒ⁵は独立にアルケニル基を表し、Ｒ⁶は独立にアルケニル基を含まない非置換又は置換の１価炭化水素基を表し、ただし全Ｒ⁶の少なくとも８０モル％はメチル基であり、ｅ、ｆ、ｇ、ｈ、ｉ、ｊ及びｋは、それぞれ、ｅ≧０、ｆ≧０、ｇ≧０、ｈ≧０、ｉ≧０、ｊ≧０及びｋ≧０を満たす数であり、但し、ｆ＋ｇ＋ｉ＞０、ｉ＋ｊ＋ｋ＞０、（ｅ＋ｆ＋ｇ＋ｈ）／（ｉ＋ｊ＋ｋ）＜１．３であり、かつ、ｅ＋ｆ＋ｇ＋ｈ＋ｉ＋ｊ＋ｋ＝１を満たす数である。）
で表される、１分子中に少なくとも２個のアルケニル基を有する、２５℃において蝋状もしくは固体である、三次元網状構造を有するオルガノポリシロキサン樹脂である［１］記載の剥離シート用重剥離組成物。
［３］．上記（Ｂ−２）が、下記平均組成式（５）：
（Ｒ⁸ ₃ＳｉＯ_1/2）_l（Ｒ⁷Ｒ⁸ ₂ＳｉＯ_1/2）_m（Ｒ⁸ ₂ＳｉＯ）_n（Ｒ⁸ＳｉＯ_3/2）_p（ＳｉＯ_4/2）_q・・・（５）
（式中、Ｒ⁷は独立にアルケニル基を表し、Ｒ⁸は独立にアルケニル基を含まない非置換又は置換の１価炭化水素基を表し、ただし全Ｒ⁸の少なくとも８０モル％はメチル基であり、ｌ、ｍ、ｎ、ｐ及びｑは、それぞれ、ｌ≧０、ｍ＞０、ｎ≧０、ｐ≧０及びｑ≧０を満たす数であり、但し、ｎ＋ｐ＋ｑ＞０、ｐ＋ｑ＜０．１であり、かつ、ｌ＋ｍ＋ｎ＋ｐ＋ｑ＝１を満たす数である。）
で表される、２５℃において液状である、末端に少なくとも２個のアルケニル基を有する直鎖状又は分岐鎖状のオルガノポリシロキサンである［１］又は［２］記載の剥離シート用重剥離組成物。
［４］．上記（Ｃ−１）成分が、下記平均組成式（６）：
（Ｒ⁹ ₃ＳｉＯ_1/2）_r（Ｒ⁹ ₂ＨＳｉＯ_1/2）_s（Ｒ⁹ＨＳｉＯ）_t（Ｒ⁹ ₂ＳｉＯ）_u（ＨＳｉＯ_3/2）_v（Ｒ⁹ＳｉＯ_3/2）_w（ＳｉＯ_4/2）_x・・・（６）
（式中、Ｒ⁹は独立にアルケニル基を含まない非置換又は置換の１価炭化水素基を表し、ｒ、ｓ、ｔ、ｕ、ｖ、ｗ及びｘは、それぞれ、ｒ≧０、ｓ≧０、ｔ≧０、ｕ≧０、ｖ≧０、ｗ≧０及びｘ≧０を満たす数であり、但し、ｔ＋ｖ＞０であり、かつ、ｓ＋ｔ＋ｕ＋ｖ＋ｗ＋ｘ＋ｙ＝１を満たす数である。）
で表される、ケイ素原子に結合した水素原子を側鎖に有するオルガノハイドロジェンポリシロキサンである［１］〜［３］のいずれかに記載の剥離シート用重剥離組成物。
［５］．上記（Ｃ−２）成分が、下記平均組成式（７）：
（Ｒ¹⁰ ₃ＳｉＯ_1/2）_α（Ｒ¹⁰ ₂ＨＳｉＯ_1/2）_β（Ｒ¹⁰ ₂ＳｉＯ）_γ（Ｒ¹⁰ＳｉＯ_3/2）_δ（ＳｉＯ_4/2）_ε・・・（７）
（式中、Ｒ¹⁰は独立にアルケニル基を含まない非置換又は置換の１価炭化水素基を表し、α、β、γ、δ、及びεは、それぞれ、α≧０、β＞０、γ≧０、δ≧０及びε≧０を満たす数であり、但し、γ＋δ＋ε＞０、δ＋ε＜０．１であり、かつ、α＋β＋γ＋δ＋ε＝１を満たす数である。）
で表される、ケイ素原子に結合した水素原子を末端に有しかつ側鎖には有しないオルガノハイドロジェンポリシロキサンである［１］〜［４］のいずれかに記載の剥離シート用重剥離組成物。
［６］．２５℃での粘度が５０〜２，０００ｍＰａ・ｓであることを特徴とする［１］〜［５］のいずれかに記載の剥離シート用重剥離組成物。
［７］．シート状基材と、該基材表面の片面又は両面に、［１］〜［６］のいずれかに項載の剥離シート用重剥離組成物の硬化皮膜とを有する剥離シート。
［８］．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５〜２０Ｎ／２５ｍｍである［７］記載の剥離シート。 Therefore, the present invention provides the following inventions.
[1]. (A) The following general formula (1):

(Wherein, R ¹ represents an alkenyl group, R ² represents an unsubstituted or substituted monovalent hydrocarbon group not containing an independently alkenyl radical, a is an integer satisfying 1 ≦ a ≦ 200.)
One-terminal-reactive organopolysiloxane having one alkenyl group at the terminal represented by the formula: 10 to 35 parts by mass of component (A) based on the total amount of component (A) and component (B) The following average composition formula (2):
R ³ _b SiO _{(4-b) / 2} ... (2)
(In the formula, R ³ is independently an unsubstituted or substituted monovalent hydrocarbon group, and b is a positive number satisfying 0 <b ≦ 3.) Organopolysiloxane having an alkenyl group: 65 to 90 parts by weight of component (B) based on 100 parts by weight of total of components (A) and (B) (C) Average compositional formula (3) below:
R ⁴ _c H _d SiO _{(4-cd) / 2}・ ・ ・ (3)
(Wherein R ⁴ is independently an unsubstituted or substituted monovalent hydrocarbon group not containing an alkenyl group, and c and d are 0.7 ≦ c ≦ 2.1, 0.001 ≦ d ≦ 1. 0 and a positive number satisfying 0.8 ≦ c + d ≦ 3.0.)
An organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms in one molecule represented by the following formula: relative to all alkenyl groups in the components (A) and (B), The amount by which the number of hydrogen atoms bonded to silicon atoms is 0.5 to 5.0 times,
(D) a platinum group metal-based catalyst: a heavy release composition for a release sheet containing an effective amount,
(B) a component having at least two alkenyl groups in one molecule, an organopolysiloxane resin (B-1) having a three-dimensional network structure, which is a waxy or solid at 25 ° C .; A combination of a liquid or linear or branched organopolysiloxane (B-2) having at least two alkenyl groups at a terminal, comprising a component (B-1) and a component (B-2). Mass ratio (B-2) / (B-1) is 0.1 to 0.5, and
The component (C) has an organohydrogenpolysiloxane (C-1) having a hydrogen atom bonded to a silicon atom in a side chain, and has a hydrogen atom bonded to a silicon atom at a terminal and has no hydrogen atom in a side chain. A release sheet comprising a combination of an organohydrogenpolysiloxane (C-2) and a mass ratio (C-2) / (C-1) of the component (C-1) to the component (C-2) of 1 to 5. Heavy release composition.
[2]. The component (B-1) has the following average composition formula (4):
_{^{(R 6 3 SiO 1/2) e}} (R 5 R 6 2 SiO 1/2) f (R 5 R 6 SiO) g (R 6 2 SiO) h (R 5 SiO 3/2) i (R 6 SiO _3/2 ) _j (SiO _4/2 ) _k・ ・ ・ (4)
(Wherein, R ⁵ independently represents an alkenyl group, R ⁶ independently represents an unsubstituted or substituted monovalent hydrocarbon group containing no alkenyl group, provided that at least 80 mol% of all R ⁶ is a methyl group. And e, f, g, h, i, j and k are numbers satisfying e ≧ 0, f ≧ 0, g ≧ 0, h ≧ 0, i ≧ 0, j ≧ 0 and k ≧ 0, respectively. Yes, provided that f + g + i> 0, i + j + k> 0, (e + f + g + h) / (i + j + k) <1.3, and is a number that satisfies e + f + g + h + i + j + k = 1.)
The heavy release for a release sheet according to [1], which is an organopolysiloxane resin having at least two alkenyl groups in one molecule and having a three-dimensional network structure, which is waxy or solid at 25 ° C. Composition.
[3]. The above (B-2) is represented by the following average composition formula (5):
_{^{(R 8 3 SiO 1/2) l}} (R 7 R 8 2 SiO 1/2) m (R 8 2 SiO) n (R 8 SiO 3/2) p (SiO 4/2) q ··· (5 )
(Wherein, R ⁷ independently represents an alkenyl group, R ⁸ independently represents an unsubstituted or substituted monovalent hydrocarbon group containing no alkenyl group, provided that at least 80 mol% of all R ⁸ is a methyl group. And l, m, n, p and q are numbers satisfying l ≧ 0, m> 0, n ≧ 0, p ≧ 0 and q ≧ 0, respectively, provided that n + p + q> 0 and p + q <0. 1 and a number satisfying l + m + n + p + q = 1.)
The heavy release composition for a release sheet according to [1] or [2], which is a linear or branched organopolysiloxane having a terminal of at least two alkenyl groups, which is liquid at 25 ° C. object.
[4]. The above component (C-1) has the following average composition formula (6):
_{^{(R 9 3 SiO 1/2) r}} (R 9 2 HSiO 1/2) s (R 9 HSiO) t (R 9 2 SiO) u (HSiO 3/2) v (R 9 SiO 3/2) w ( SiO _4/2 ) _{x ・ ・ ・} (6)
(Wherein, R ⁹ independently represents an unsubstituted or substituted monovalent hydrocarbon group containing no alkenyl group, and r, s, t, u, v, w, and x are respectively r ≧ 0, s ≧ 0, t ≧ 0, u ≧ 0, v ≧ 0, w ≧ 0, and x ≧ 0, provided that t + v> 0 and s + t + u + v + w + x + y = 1.)
The heavy release composition for a release sheet according to any one of [1] to [3], which is an organohydrogenpolysiloxane having a hydrogen atom bonded to a silicon atom in a side chain represented by the following formula:
[5]. The component (C-2) has the following average composition formula (7):
(R ¹⁰ ₃ SiO _1/2 ) _α (R ¹⁰ ₂ HSiO _1/2 ) _β (R ¹⁰ ₂ SiO) _γ (R ¹⁰ SiO _3/2 ) _δ (SiO _4/2 ) _ε (7)
(Wherein, R ¹⁰ independently represents an unsubstituted or substituted monovalent hydrocarbon group containing no alkenyl group, and α, β, γ, δ, and ε are α ≧ 0, β> 0, γ, respectively) It is a number that satisfies ≧ 0, δ ≧ 0, and ε ≧ 0, provided that γ + δ + ε> 0, δ + ε <0.1, and α + β + γ + δ + ε = 1.)
The heavy release composition for a release sheet according to any one of [1] to [4], which is an organohydrogenpolysiloxane having a hydrogen atom bonded to a silicon atom at a terminal and not having a side chain represented by object.
[6]. The heavy release composition for a release sheet according to any one of [1] to [5], which has a viscosity at 25 ° C of 50 to 2,000 mPa · s.
[7]. A release sheet having a sheet-like substrate and a cured film of the heavy release composition for a release sheet according to any one of [1] to [6] on one or both surfaces of the substrate.
[8]. The release sheet according to [7], wherein a peel strength is 5 to 20 N / 25 mm measured by attaching a Tesa 7475 tape to the cured film and measuring at an angle of 180 ° and a release speed of 0.3 m / min.

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

It is a peeling force measurement result at the time of zipping. It is a normal peeling force measurement result without zipping.

（式中、Ｒ¹はアルケニル基であり、Ｒ²は独立にアルケニル基を含まない非置換又は置換の１価炭化水素基であり、ａは１≦ａ≦２００を満たす整数である。）
で表される、末端に１個のアルケニル基を有する片末端反応性オルガノポリシロキサンである。この（Ａ）成分末端に１個のアルケニル基を有する片末端反応性オルガノポリシロキサンを使用して架橋密度を調整することで、本発明の剥離シート用重剥離組成物（以下、重剥離組成物と略す場合がある）は、ジッピングのない剥離シートを提供することが可能となる。なお、（Ａ）成分は１種単独で又は２種以上を適宜組み合わせて用いることができる。 Hereinafter, the present invention will be described in detail.
[(A) component]
The component (A) has the following general formula (1):

(In the formula, R ¹ is an alkenyl group, R ² is an unsubstituted or substituted monovalent hydrocarbon group containing no independently alkenyl radical, a is an integer satisfying 1 ≦ a ≦ 200.)
And a one-terminal-reactive organopolysiloxane having one alkenyl group at the terminal. By adjusting the crosslink density using the one-terminal reactive organopolysiloxane having one alkenyl group at the terminal of the component (A), the heavy release composition for a release sheet of the present invention (hereinafter referred to as the heavy release composition) ) May provide a release sheet without zipping. The component (A) can be used alone or in an appropriate combination of two or more.

In the general formula (1), R ¹ is independently an alkenyl group, and the number of carbon atoms is usually 2 to 8, preferably 2 to 4. Specific examples include a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group and the like, and a vinyl group is preferable.

R ² is independently an unsubstituted or substituted monovalent hydrocarbon group containing no alkenyl group, and is not particularly limited as long as it does not have an alkenyl group. Usually, 1 to 12, preferably 1 to 10 monovalent hydrocarbon groups are exemplified. Examples of the unsubstituted or substituted monovalent hydrocarbon group include an alkyl group 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 cyclohexyl group; Aryl groups such as group, tolyl group, xylyl group and naphthyl group; aralkyl groups such as benzyl group and phenethyl group; some or all of the hydrogen atoms of these groups are halogen atoms such as chlorine, fluorine and bromine And substituted halogenated alkyl groups such as chloromethyl group, 3-chloropropyl group, and 3,3,3-trifluoropropyl group. Among them, an alkyl group is preferable, and a methyl group is more preferable.

a is the integer satisfying 1 ≦ a ≦ 200, and preferably the number of integer satisfying 5 ≦ a ≦ 100, more preferably 5 ≦ a ≦ 30. When a exceeds 200, it is difficult to obtain the target heavy release effect because the component (A) functions as a light release component. In addition, there is a problem that the viscosity of the composition becomes high and the composition cannot be used unless diluted with a solvent.

Specific examples of the component (A) include the following compounds (in the formula, Bu represents a butyl group).

  The content of the component (A) is 10 to 35 parts by mass based on 100 parts by mass of the total of the components (A) and (B). When the content of the component (A) is less than 10 parts by mass, the crosslinked density of the cured product becomes high, and there is a problem that zipping occurs. When the content of the component (A) is more than 35 parts by mass, the crosslink density of the cured product is unnecessarily reduced, so that it is difficult to obtain a target heavy release effect.

[Component (B)]
The component (B) has the following average composition formula (2):
R ³ _b SiO _{(4-b) / 2} ... (2)
(In the formula, R ³ is independently an unsubstituted or substituted monovalent hydrocarbon group, and b is a positive number satisfying 0 <b ≦ 3.) It is an organopolysiloxane having an alkenyl group. The component (B) can be used alone or in an appropriate combination of two or more.

In the above average composition formula (2), 0.1 to 40 mol% of the unsubstituted or substituted monovalent hydrocarbon group represented by R ³ is preferably an alkenyl group, and 0.2 to 20 mol% More preferred. When the content of the alkenyl group satisfies the range of 0.1 to 40 mol%, the crosslinking reaction proceeds sufficiently, and a film having a high heavy peeling effect can be obtained.

As the alkenyl group in the component (B), the same alkenyl groups as those specifically exemplified as R ¹ in the formula (1) of the component (A) can be mentioned, and among them, a vinyl group is preferable. Examples of the unsubstituted or substituted monovalent hydrocarbon group other than the alkenyl group in the component (B) are the same as those specifically exemplified as R ^{2 in} the general formula (1) of the component (A). Among them, an alkyl group is preferable, and a methyl group is more preferable.

  In the present invention, the component (B) includes an organopolysiloxane resin (B-1) having at least two alkenyl groups in one molecule, being waxy or solid at 25 ° C. and having a three-dimensional network structure, A combination of a linear or branched organopolysiloxane (B-2) having at least two alkenyl groups at terminals, which is liquid at 25 ° C., comprising a component (B-1) and a component (B-2) The mass ratio (B-2) / (B-1) to the component is 0.1 to 0.5.

[(B-1) component]
The term "waxy" means a gum (raw rubber) having almost no self-flowing property at 25 ° C of 10,000 Pa · s or more, particularly 100,000 Pa · s or more. The measurement of the viscosity is a value of the absolute viscosity measured by a B-type rotational viscometer at 25 ° C. (the same applies hereinafter).

As (B-1), the following average composition formula (4):
^{_{(R 6 3 SiO 1/2) e}} (R 5 R 6 2 SiO 1/2) f (R 5 R 6 SiO) g (R 6 2 SiO) h (R 5 SiO 3/2) i (R 6 SiO _3/2 ) _j (SiO _4/2 ) _k・ ・ ・ (4)
(Wherein, R ⁵ independently represents an alkenyl group, R ⁶ independently represents an unsubstituted or substituted monovalent hydrocarbon group containing no alkenyl group, provided that at least 80 mol% of all R ⁶ is a methyl group. And e, f, g, h, i, j and k are numbers satisfying e ≧ 0, f ≧ 0, g ≧ 0, h ≧ 0, i ≧ 0, j ≧ 0 and k ≧ 0, respectively. Yes, provided that f + g + i> 0, i + j + k> 0, (e + f + g + h) / (i + j + k) <1.3, and a number that satisfies e + f + g + h + i + j + k = 1.)
And a molecule essentially containing at least two alkenyl groups bonded to a silicon atom and a trifunctional siloxane unit and / or SiO _4/2 unit in the molecule.

In the above average composition formula (4), the alkenyl group represented by R ⁵ is the same as that specifically exemplified as R ¹ in the formula (1) of the component (A). preferable. Examples of the unsubstituted or substituted monovalent hydrocarbon group other than the alkenyl group represented by R ⁶ are the same as those specifically exemplified as R ² in the formula (1) of the component (A). at least 80 mole% of R ⁵ is a methyl group. If the proportion of the methyl group is less than 80 mol% of the total R ⁵ , the composition will be inferior in compatibility with the component (A), so that the composition will be cloudy separated and a uniform film may not be obtained.

  e is 0 to 0.65, f is 0 to 0.65, g is 0 to 0.5, h is 0 to 0.5, i is 0 to 0.8, j is 0 to 0.8, and k is It is preferably a number from 0 to 0.6. Further, f + g + i is preferably a number of 0.1 to 0.8, i + j + k is preferably a number of 0.1 to 0.8, particularly preferably 0.2 to 0.6, and (e + f + g + h) / ( i + j + k) is preferably a number from 0.6 to 1.25.

Examples of the organopolysiloxane resin represented by the above average composition formula (4) include the following.
(Me ₃ SiO _1/2 ) _e (ViMe ₂ SiO _1/2 ) _f (SiO _4/2 ) _k
(ViMe ₂ SiO _1/2 ) _f (SiO _4/2 ) _k
(ViMeSiO) _g (Me ₂ SiO) _h (MeSiO _3/2 ) _j
(ViMe ₂ SiO _1/2 ) _f (Me ₂ SiO) _h (ViSiO _3/2 ) _i
(ViMe ₂ SiO _1/2 ) _f (Me ₂ SiO) _h (MeSiO _3/2 ) _j
(Me ₃ SiO _1/2 ) _e (ViMe ₂ SiO _1/2 ) _f (Me ₂ SiO) _h (MeSiO _3/2 ) _j
(Me ₃ SiO _1/2 ) _e (ViMe ₂ SiO _1/2 ) _f (Me ₂ SiO) _h (ViMeSiO) _g (MeSiO _3/2 ) _j
(In the formula, Me represents a methyl group, Vi represents a vinyl group, and e, f, g, h, i, j, and k are as defined in the above average composition formula (4).)
And the like. In particular, it is more preferable to use an organopolysiloxane resin composed of Me ₃ SiO _1/2 , ViMe ₂ SiO _1/2 and SiO _4/2 units. By using such an organopolysiloxane resin, the crosslinked density of the obtained cured product becomes sufficiently high, and a desired heavy release effect can be obtained.

[(B-2) component]
The linear or branched organopolysiloxane having a terminal at least two alkenyl groups which is liquid at 25 ° C. has the following average composition formula (5):
^{_{(R 8 3 SiO 1/2) l}} (R 7 R 8 2 SiO 1/2) m (R 8 2 SiO) n (R 8 SiO 3/2) p (SiO 4/2) q ··· (5 )
(Wherein, R ⁷ independently represents an alkenyl group, R ⁸ independently represents an unsubstituted or substituted monovalent hydrocarbon group containing no alkenyl group, provided that at least 80 mol% of all R ⁸ is a methyl group. Yes, l, m, n, p and q are numbers satisfying l ≧ 0, m> 0, n ≧ 0, p ≧ 0 and q ≧ 0, respectively, provided that n + p + q> 0 and p + q <0. 1 and a number satisfying l + m + n + p + q = 1.)
The compound represented by these is mentioned.

In the above average composition formula (5), examples of the alkenyl group represented by R ⁷ are the same as those specifically exemplified as R ¹ in the formula (1) of the component (A). preferable. The unsubstituted or substituted monovalent hydrocarbon group other than the alkenyl group represented by R ⁸ is the same as that specifically exemplified as R ² in the formula (1) of the component (A), at least 80 mole% of the total R ⁸ is a methyl group. If the proportion of the methyl group is less than 80 mol% of the total R ⁸ , the composition is inferior in compatibility with the component (A), so that the composition may be cloudy separated and a uniform film may not be obtained.

で表される直鎖状ポリシロキサン、

で表される分岐鎖状ポリシロキサン等が挙げられる。中でも、ＶｉＭｅ₂ＳｉＯ_1/2、及びＭｅ₂ＳｉＯ単位で構成された直鎖状オルガノポリシロキサンを用いることがより好ましい。このようなオルガノポリシロキサンを用いることで、得られる硬化物の架橋密度の調整がより容易となる。It is preferable that 1 is a number of 0 to 0.65, m is 0.01 to 0.65, n is 0 to 1, p is 0 to 0.1, and q is 0 to 0.1. Further, n + p + q is preferably a number of 0.5 to 1, particularly 0.7 to 1, and p + q is preferably a number of less than 0.1. When p + q exceeds 0.1, the crosslinked density of the cured product becomes high, and a problem such as occurrence of zipping occurs.
Specific examples of the above average composition formula (5) include:

A linear polysiloxane represented by

And the like. Among them, it is more preferable to use a linear organopolysiloxane composed of ViMe ₂ SiO _1/2 and Me ₂ SiO units. The use of such an organopolysiloxane makes it easier to adjust the crosslink density of the resulting cured product.

  The viscosity of the component (B) at 25 ° C. is preferably 1,000 mPa · s or less, more preferably 0.5 to 1,000 mPa · s, and still more preferably 2 to 500 mPa · s. When the viscosity exceeds 1,000 mPa · s, there is a problem that the viscosity of the composition becomes high and the composition cannot be used unless diluted with a solvent.

  The proportion of the organopolysiloxane resin (B-1) having a three-dimensional network structure and the linear or branched organopolysiloxane (B-2) in the component (B) is also important for the composition of the present invention. Is one of the important factors. That is, the mass ratio ((B-2) / (B-1)) of the component (B-1) and the component (B-2) needs to be 0.1 to 0.5, and 0.2 to 0. 4 is preferred. When (B-2) / (B-1) is less than 0.1, the crosslinked density of the cured product becomes high, and zipping occurs. Further, when (B-2) / (B-1) exceeds 0.5, it is difficult to obtain the target heavy release effect because the crosslink density of the cured product is reduced more than necessary. Become.

  The content of the component (B) is 65 to 90 parts by mass based on 100 parts by mass in total of the component (A) and the component (B).

[(C) component]
The component (C) has the following average composition formula (3):
R ⁴ _c H _d SiO _{(4-cd) / 2}・ ・ ・ (3)
(Wherein R ⁴ is independently an unsubstituted or substituted monovalent hydrocarbon group not containing an alkenyl group, and c and d are 0.7 ≦ c ≦ 2.1, 0.001 ≦ d ≦ 1. 0 and a positive number satisfying 0.8 ≦ c + d ≦ 3.0.)
Is an organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms in one molecule.

  The component (C) functions as a crosslinking agent that reacts with an alkenyl group contained in the components (A) and (B) by a hydrosilylation reaction to crosslink. From such a viewpoint, the viscosity of the component (C) at 25 ° C. is preferably 1,000 mPa · s or less, more preferably 0.5 to 1,000 mPa · s, and still more preferably 2 to 200 mPa · s. Further, from the viewpoint of the balance of crosslinking, the hydrogen atom bonded to the silicon atom in the component (C) is 0.5 to 5.0 mole times the total alkenyl group in the component (A) and the component (B). Preferably, the amount is controlled to be 0.7 to 3.0 mole times. If the amount does not satisfy the amount of 0.5 to 5.0 times, the balance of crosslinking may be inappropriate.

  In the component (C), the content of the hydrogen atom bonded to the silicon atom is preferably in the range of 0.001 to 0.02 mol, and more preferably in the range of 0.002 to 0.017 mol, per 1 g of the component (C). Is more preferable.

In the above average composition formula (3), the unsubstituted or substituted monovalent hydrocarbon group containing no alkenyl group represented by R ⁴ is specifically exemplified as R ² in the formula (1) of the component (A). However, it is preferable that at least 50 mol%, typically 60 to 100 mol% of all R ⁴ is a methyl group. When the proportion of the methyl group is less than 50 mol% of the total R ⁴ , the compatibility with the component (A) and the component (B) is inferior, and the problem that the composition becomes cloudy or phase-separates may occur. There is. c is 0.7 ≦ c ≦ 2.1, d is 0.001 ≦ d ≦ 1.0, and c + d is a positive number satisfying 0.8 ≦ c + d ≦ 3.0.

  In the present invention, the component (C) includes an organohydrogenpolysiloxane (C-1) having a hydrogen atom bonded to a silicon atom in a side chain and a hydrogen atom bonded to a silicon atom at a terminal and having a hydrogen atom bonded to a side chain. Consists of a combination of organohydrogenpolysiloxane (C-2) having no. The component (C-1) is a component for mainly providing adhesion to the substrate, and the component (C-2) is a component for adjusting the crosslink density. As the component (C), one type can be used alone, or two or more types can be used in appropriate combination.

As (C-1), the following average composition formula (6):
^{_{(R 9 3 SiO 1/2) r}} (R 9 2 HSiO 1/2) s (R 9 HSiO) t (R 9 2 SiO) u (HSiO 3/2) v (R 9 SiO 3/2) w ( SiO _4/2 ) _{x ・ ・ ・} (6)
(Wherein, R ⁹ independently represents an unsubstituted or substituted monovalent hydrocarbon group containing no alkenyl group, and r, s, t, u, v, w, and x are respectively r ≧ 0, s ≧ 0, t ≧ 0, u ≧ 0, v ≧ 0, w ≧ 0, and x ≧ 0, provided that t + v> 0 and s + t + u + v + w + x + y = 1.)
The compound represented by these is mentioned.

Examples of the unsubstituted or substituted monovalent hydrocarbon group other than the alkenyl group represented by R ⁹ are the same as those specifically exemplified as R ² in the formula (1) of the component (A). Groups are preferred, and methyl groups are more preferred.

  r is 0 to 0.65, s is 0 to 0.65, t is 0 to 1, u is 0 to 1, v is 0 to 1, w is 0 to 0.75, and x is 0 to 0.65. It is preferably a number. Further, t + v is preferably 0.01 to 1.

で表される環状オルガノハイドロジェンポリシロキサン、

で表される直鎖状オルガノハイドロジェンポリシロキサン、
（Ｍｅ₃ＳｉＯ_1/2）_r（ＭｅＨＳｉＯ）_t（ＳｉＯ_4/2）_x
（Ｍｅ₂ＨＳｉＯ_1/2）_s（ＭｅＨＳｉＯ）_t（Ｍｅ₂ＳｉＯ）_u（ＳｉＯ_4/2）_x
（Ｍｅ₃ＳｉＯ_1/2）_r（ＭｅＨＳｉＯ）_t（ＭｅＳｉＯ_3/2）_w
（Ｍｅ₃ＳｉＯ_1/2）_r（ＭｅＨＳｉＯ）_t（ＨＳｉＯ_3/2）_v
（ＭｅＨＳｉＯ）_t（ＭｅＳｉＯ_3/2）_w
（式中、ｒ、ｓ、ｔ、ｕ、ｖ、ｗ及びｘは、上記平均組成式（６）で定義したとおりである。）
で表される分岐鎖状オルガノハイドロジェンポリシロキサン等が挙げられる。特に、Ｍｅ₃ＳｉＯ_1/2及びＭｅＨＳｉＯ単位、又はＭｅ₃ＳｉＯ_1/2、ＭｅＨＳｉＯ及びＭｅ₂ＳｉＯ単位で構成された直鎖状オルガノポリシロキサンを用いることがより好ましい。このようなオルガノポリシロキサンを用いることで、基材に対する密着性を付与することが可能となる。Specific examples of the above average composition formula (6) include:

Represented by a cyclic organohydrogenpolysiloxane,

A linear organohydrogenpolysiloxane represented by
(Me ₃ SiO _1/2 ) _r (MeHSiO) _t (SiO _4/2 ) _x
(Me ₂ HSiO _1/2 ) _s (MeHSiO) _t (Me ₂ SiO) _u (SiO _4/2 ) _x
(Me ₃ SiO _1/2 ) _r (MeHSiO) _t (MeSiO _3/2 ) _w
(Me ₃ SiO _1/2 ) _r (MeHSiO) _t (HSiO _3/2 ) _v
(MeHSiO) _t (MeSiO _3/2 ) _w
(In the formula, r, s, t, u, v, w, and x are as defined in the above average composition formula (6).)
And a branched-chain organohydrogenpolysiloxane represented by In particular, it is more preferable to use Me ₃ SiO _1/2 and MeHSiO units or a linear organopolysiloxane composed of Me ₃ SiO _1/2 , MeHSiO and Me ₂ SiO units. By using such an organopolysiloxane, it is possible to impart adhesion to a substrate.

(C-2) ^{_{The, (R 10 3 SiO 1/2)}} α (R 10 2 HSiO 1/2) β (R 10 2 SiO) γ (R 10 SiO 3/2) δ (SiO 4/2) _ε (7)
(Wherein, R ¹⁰ independently represents an unsubstituted or substituted monovalent hydrocarbon group containing no alkenyl group, and α, β, γ, δ, and ε are α ≧ 0, β> 0, γ, respectively) It is a number that satisfies ≧ 0, δ ≧ 0 and ε ≧ 0, provided that γ + δ + ε> 0, δ + ε <0.1, and α + β + γ + δ + ε = 1.)
)).

Examples of the unsubstituted or substituted monovalent hydrocarbon group other than the alkenyl group represented by R ¹⁰ include those specifically exemplified as R ² in the formula (1) of the component (A). Is preferable, and a methyl group is more preferable.

  α is preferably 0 to 0.65, β is 0.01 to 0.65, γ is 0 to 1, δ is 0 to 0.1, and ε is preferably 0 to 0.1. Further, γ + δ + ε is preferably a number of 0.5 to 1, particularly 0.7 to 1, and δ + ε is preferably a number less than 0.1. When δ + ε exceeds 0.1, the crosslinked density of the cured product may be increased.

で表される直鎖状オルガノハイドロジェンポリシロキサン、

で表される分岐鎖状オルガノハイドロジェンポリシロキサン等が挙げられる。上記した分岐鎖状オルガノハイドロジェンポリシロキサンの構造において、各（ＣＨ₃）₂ＳｉＯ単位の数を示す０〜６０の中で少なくとも１つは１〜６０であり、０〜５０のうち、少なくとも１つは１〜５０であることが好ましい。特にＭｅ₂ＨＳｉＯ_1/2及びＭｅ₂ＳｉＯ単位で構成された直鎖状オルガノポリシロキサンを用いることがより好ましい。このようなオルガノポリシロキサンを用いることで、得られる硬化物の架橋密度の調整が容易となる。Specific examples of the above average composition formula (7) include:

A linear organohydrogenpolysiloxane represented by

And a branched-chain organohydrogenpolysiloxane represented by In the structure of the above-mentioned branched organohydrogenpolysiloxane, at least one of 0 to 60 indicating the number of each (CH ₃ ) ₂ SiO unit is 1 to 60, and at least 1 One is preferably 1 to 50. In particular, it is more preferable to use a linear organopolysiloxane composed of Me ₂ HSiO _1/2 and Me ₂ SiO units. The use of such an organopolysiloxane facilitates adjustment of the crosslink density of the obtained cured product.

  Component (C), an organohydrogenpolysiloxane (C-1) component essentially having a hydrogen atom bonded to a silicon atom in a side chain, and a hydrogen atom bonded to a silicon atom at a terminal and The proportion of the organohydrogenpolysiloxane (C-2) not in the chain is also an important factor of the composition of the present invention. That is, the mass ratio ((C-2) / (C-1)) of the component (C-1) to the component (C-2) needs to be 1 to 5. When (C-2) / (C-1) is less than 1, the cross-linking density of the cured product becomes high, which causes a problem that zipping occurs. When (C-2) / (C-1) is more than 5, the crosslink density of the cured product is unnecessarily reduced, so that it is difficult to obtain the target heavy release effect.

[(D): platinum group metal based catalyst]
The platinum group metal-based catalyst of the component (D) is a catalyst for accelerating the addition reaction between the components (A) and (B) and the component (C), and is known to those skilled in the art as what promotes a 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, and among them, platinum-based catalysts are particularly preferably used. Examples of the platinum-based catalyst include chloroplatinic acid, an alcohol solution or aldehyde solution of chloroplatinic acid, and complexes of chloroplatinic acid with various olefins or vinylsiloxane. More specifically, a platinum catalyst obtained by modifying chloroplatinic acid with 1,3-divinyltetramethyldisiloxane is exemplified.

  The compounding amount of the component (D) may be a so-called effective amount as a catalyst. Specifically, from the viewpoint of obtaining a good cured film and economical, the components (A), (B) and (C) The amount is in the range of 0.1 to 1,000 ppm, more preferably 1 to 500 ppm, as the mass of the platinum group metal, based on the total mass of the components.

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

-Alkenyl group-containing compound other than the components (A) and (B) The composition of the present invention contains, in addition to the components (A) and (B), an alkenyl group-containing compound that undergoes an addition reaction with the component (C). You may. As such an alkenyl group-containing compound other than the components (A) and (B), those which participate in the formation of a cured product are preferable, and the components (A) and (B) having at least one alkenyl group per molecule. And other organopolysiloxanes. The molecular structure may be, for example, any of linear, cyclic, branched, and three-dimensional networks.

((E) component)
-Addition reaction control agent In order to ensure the pot life, an addition reaction control agent can be added to the composition of the present invention. The addition reaction controlling agent is not particularly limited as long as it has a curing inhibiting effect on the hydrosilylation catalyst of the above-mentioned component (D), and a conventionally known one can also be used. Specific examples thereof include phosphorus-containing compounds such as triphenylphosphine; nitrogen-containing compounds such as tributylamine, tetramethylethylenediamine, and benzotriazole; sulfur-containing compounds; 1-ethynylcyclohexanol, 3-methyl-1-butyne-3-. Acetylene alcohols such as all, 3,5-dimethyl-1-hexyn-3-ol, 3-methyl-1-penten-3-ol and phenylbutynol; 3-methyl-3-penten-1-yne And acetylene compounds such as 3,5-dimethyl-1-hexyn-3-yne; compounds containing two or more alkenyl groups; hydroperoxy compounds; and maleic acid derivatives.

  The degree of the curing suppression effect of the addition reaction controlling agent differs depending on the chemical structure of the addition reaction controlling agent. Therefore, it is preferable to adjust the amount of each of the addition reaction control agents to be used to an optimum amount. By adding an optimal amount of the addition reaction controlling agent, the composition becomes excellent in long-term storage stability at room temperature and heat curability.

  Further, if necessary within the range not hindering the effects of the present invention, other, known antioxidants as optional components, pigments, stabilizers, antistatic agents, antifoaming agents, adhesion improvers, thickeners, silica And other inorganic fillers.

[Heavy release composition for release sheet]
The heavy release composition of the present invention preferably has a viscosity at 25 ° C. of 50 to 2,000 mPa · s, particularly 50 to 1,000 mPa · s. If the viscosity is out of this range, problems may occur such as inability to apply when forming a cured film on the substrate, and not being a uniform film.

  Since the heavy release composition of the present invention does not require a solvent, it can be a solventless heavy release composition.

[Method for producing heavy release composition for release sheet]
In the heavy release composition of the present invention, a method in which the components (A) to (C) and the optional components are uniformly mixed in advance and then the component (D) is added immediately before use is desirable from the viewpoint of pot life.

[Coated product (release sheet)]
The release sheet of the present invention is a release sheet having a sheet-shaped substrate and a cured film of the heavy release composition on one or both surfaces of the substrate surface. A cured film can be formed by applying the above-mentioned heavy release composition to one or both surfaces of the substrate surface and heating.

For example, a heavy release composition 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 After applying 0.01 to 100 g / m ² on one or both sides of a sheet-like substrate such as paper or film using a coating method such as cast coating, the coating is performed at 50 to 200 ° C. for 1 to 120 seconds. By heating, a cured film can be formed on the substrate. When forming release layers on both surfaces of the substrate, it is preferable to carry out the operation of forming a cured film on each side of the substrate.

  In the present invention, the release sheet includes not only a sheet-shaped substrate made of paper, but also a sheet formed of various known films. Examples of the substrate include polyethylene-laminated paper, glassine paper, high-quality paper, kraft paper, various coated papers such as clay-coated paper, synthetic paper such as YUPO, polyethylene films, polypropylene films such as CPP and OPP, and polyester films such as polyethylene terephthalate films. , A polyamide film, a polyimide film, a polylactic acid film, a polyphenol film, a polycarbonate film and the like. Process paper for producing artificial leather, ceramic sheets, double-sided separators and the like can also be used as a base material. In order to improve the adhesiveness between the substrate and the release layer, a substrate which has been subjected to a corona treatment, an etching treatment, a primer treatment or a plasma treatment may be used.

[Release sheet]
In the present invention, the release sheet prepared by applying the heavy release composition to a polyethylene laminated paper base material at 0.9 to 1.2 g / m ² and then heating at 140 ° C. for 30 seconds is a FINAT test method. Is 5 to 20 N / 25 mm. Thereby, it can be used as a peeling material having a high heavy peeling effect. Further, a small change in the peeling force over time is also a feature of the release sheet of the present invention. In the present invention, the term "heavy release composition" refers to a composition having the above-mentioned peeling force according to the above-mentioned measuring method.

[Initial peeling force measurement method]
After storing the release sheet obtained by the above-described curing method at 25 ° C. for 24 hours, the release force measured by the FINAT test method in the same manner as above is defined as the initial release force. In the present invention, 5 to 15 N / 25 mm is preferable. Details of the measurement method are the methods described in Examples.

[Measurement method of peel force over time]
After storing the release sheet obtained by the above-described curing method at 50 ° C. for 7 days, the release force measured by the FINAT test method in the same manner as described above is defined as the release force over time. In the present invention, 5 to 15 N / 25 mm is preferable. Details of the measurement method are the methods described in Examples.

  Hereinafter, the present invention will be specifically described with reference to Synthesis Examples, Examples, and Comparative Examples, but the present invention is not limited to the following Examples.

[Synthesis Example 1] Preparation of platinum catalyst A reaction product of hexachloroplatinic acid and 1,3-divinyltetramethyldisiloxane was prepared to have a viscosity of 400 mPa · s and an average molecular formula such that the platinum content was 0.5% by mass. : ViMe ₂ SiO (SiMe ₂ O) ₁₅₀ Platinum catalyst (catalyst (D)) used in the present Examples and Comparative Examples was prepared by diluting with ₁₅₀ SiMe ₂ Vi linear dimethylpolysiloxane. Me represents a methyl group, and Vi represents a vinyl group.

Hereinafter, the raw materials used in the examples will be described.
(A) Average molecular formula: Organopolysiloxane represented by ViMe ₂ SiO (SiMe ₂ O) ₁₄ SiMe ₃ (B-1) Me ₃ SiO _1/2 , ViMe ₂ SiO _1/2 , and SiO _4/2 units An organopolysiloxane having a molar ratio of Me ₃ SiO _1/2 and ViMe ₂ SiO _1/2 to SiO _4/2 of 0.8 and a vinyl group content of 0.085 mol / 100 g based on solid content. Resin (solid at 25 ° C)
(B-2-1) Organopolysiloxane represented by the average molecular formula: ViMe ₂ SiO (SiMe ₂ O) ₈ SiMe ₂ Vi (liquid at 25 ° C.)
(B-2-2) Organopolysiloxane represented by the average molecular formula: ViMe ₂ SiO (SiMe ₂ O) ₁₅₀ SiMe ₂ Vi (liquid at 25 ° C.)
(C-1-1) Average molecular formula: Me ₃ SiO (SiHMeO) ₄₆ A methyl hydrogen siloxane represented by SiMe ₃ (C-1-2) Average molecular formula: Me ₃ SiO (SiHMeO) ₁₀₀ SiMe ₃ Methyl hydrogen siloxane (C-1-3) average molecular formula: Me ₃ SiO (SiHMeO) ₄₅ (SiMe ₂ O) ₁₇ SiMe ₃ Methyl hydrogen siloxane (C-2-1) average molecular formula: HMe ₂ SiO Methyl hydrogen siloxane represented by (SiMe ₂ O) ₈ SiMe ₂ H (C-2-2) Average molecular formula: HMe ₂ SiO (SiMe ₂ O) ₆₀ Methyl hydrogen siloxane represented by SiMe ₂ H (D) Platinum catalyst (E) 1-ethynylcyclohexanol obtained in Preparation Example 1 (addition reaction control agent)
(F) 1,3,5,7-tetramethyltetravinyltetracyclosiloxane (H / Vi regulator)

[Example 1]
(1) Average molecular formula: ViMe ₂ SiO (SiMe ₂ O) ₁₄ SiMe ₃ A linear dimethylpolysiloxane (A) whose one end is blocked with a vinyl group, 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, A xylene solution of the organopolysiloxane resin (B-1) having an amount of 0.085 mol / 100 g was mixed at a ratio of 10:50 by mass in terms of active ingredient. In 60 parts by mass of this liquid, a linear dimethylpolysiloxane (B-2-1) 13 represented by the average molecular formula: ViMe ₂ SiO (SiMe ₂ O) ₈ SiMe ₂ Vi and having both ends blocked by a vinyl group Parts by mass, average molecular formula: Me ₃ SiO (SiHMeO) ₄₆ 4.7 parts by mass of methyl hydrogen siloxane (C-1-1) having SiH only in a side chain represented by ₄₆ SiMe ₃ , and average molecular formula: HMe ₂ SiO (SiMe ₂ O) ₈ 8.5 parts by mass of methylhydrogensiloxane (C-2-1) having SiH only at the terminal represented by 8SiMe ₂ H was mixed at 150 ° C. under reduced pressure of 20 mmHg or less. Removal gave a clear liquid (molar ratio of total SiH groups to total alkenyl groups in the composition, ie H / Vi = 1.2).
(2) To 100 parts by mass of this liquid, 0.2 part by mass of 1-ethynylcyclohexanol (component E) as an addition reaction control agent and 2 parts by mass of the platinum catalyst (D) obtained in Synthesis Example 1 were uniformly mixed. By mixing, a transparent composition having a viscosity of 890 mPa · s was obtained.

[Examples 2 to 12, Comparative Examples 1 to 8]
Thereafter, the components (A), (B) and (C) are mixed in the same manner as in Example 1, and then xylene in the component (B-1) is removed by distillation under reduced pressure. Then, the other component (F), the component (E) as an addition reaction controlling agent, and the platinum catalyst (D) obtained in Synthesis Example 1 were mixed to obtain a heavy release composition shown below. The amounts (unit: parts by mass) are shown in the following table. In the table, the content of the component (A) / the total amount of the components (A) and (B) is the content of the component (A) with respect to 100 parts by mass of the total of the components (A) and (B). Parts by mass), (B-2) / (B-1) are (B-2) component content (parts by mass) / (B-1) component content (parts by mass), (C-2) / (C -1) represents (C-2) component content (parts by mass) / (C-1) component content (parts by mass).

  The viscosity (absolute viscosity measured by a B-type rotational viscometer at 25 ° C.) of the composition obtained as described above was measured, and a release sheet was prepared by the following method to evaluate the release force. The results obtained are shown in the table. In the table, "Z" indicates that zipping is performed. The peeling force maintenance ratio [%] is a value obtained from a temporal peeling force / initial peeling force × 100 [%].

  FIG. 1 shows the results of measuring the peeling force during zipping, and FIG. 2 shows the results of measuring the normal peeling force without zipping. As shown in FIG. 1, in the case of zipping, the peeling force is not stable, and it is difficult to accurately measure the peeling force.

[Hardening method of heavy release composition]
After preparing the heavy release composition, the heavy release composition is applied to a polyethylene laminated paper base material at 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.

[Method of measuring initial peel force]
After the release sheet obtained by the above method of curing and stored for 24 hours at 25 ° C., attached width 25mm acrylic pressure-sensitive adhesive tape Tesa7475 (Tesa Tape.Inc trade name), a 70 ° C. dryer of 20 g / cm ² A sample was taken out after applying a load 24 hours later. After air cooling for about 30 minutes, the Tesa 7475 tape of the sample was peeled off at a rate of 0.3 m / min at an angle of 180 ° using a tensile tester (DSC-500 type tester manufactured by Shimadzu Corporation). The required force was measured.

[Method of measuring peel force over time]
After the release sheet obtained by the above-described curing method was stored at 50 ° C. for 7 days, a 25-mm-wide acrylic pressure-sensitive adhesive tape Tesa 7475 (trade name, manufactured by Tesa Tape. Inc.) was stuck, and dried in a 70 ° C. drier at 20 g. / M ² and stored for 24 hours as a sample. After air cooling for about 30 minutes, the sample TESA-7475 tape is peeled off at a rate of 0.3 m / min at an angle of 180 ° using a tensile tester (DSC-500 type tester manufactured by Shimadzu Corporation). The required force was measured.

  From the above results, the heavy release composition of the present invention (Examples 1 to 12) has high fluidity at 25 ° C, and the release sheet has a high release force of 5 N / 25 mm or more at the initial stage, In addition, even after the elapse of time, it has a peeling force of 85% or more relative to the initial state. Also, there is no occurrence of zipping at the time of peeling at the initial stage and after the elapse 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 the component (A) was increased (Comparative Example 2) and when the component (C-1) was reduced and the component (C-2) was increased (Comparative Examples 7 and 8), the crosslinking density was low. As a result, the release sheet became lightly released. Conversely, when the component (A) is not contained (Comparative Example 1), when the component (B-2) is not contained (Comparative Example 3), the component (C-1) is increased and the component (C-2) is decreased. In Comparative Examples 5 and 6, the crosslink density was too high, and zipping occurred during peeling. In addition, when the component (B-2) was increased as in Comparative Example 4, the viscosity of the composition was too low, resulting in a failure to coat the base material. From the above results, it is considered that the compositions shown in Comparative Examples 1 to 8 are unsuitable for the above uses.

  Note that the present invention is not limited to the above embodiment. The above embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and has the same effect. Within the technical scope of

Claims (8)

(A) The following general formula (1):

(In the formula, R ¹ is an alkenyl group, R ² is an unsubstituted or substituted monovalent hydrocarbon group containing no independently alkenyl radical, a is an integer satisfying 1 ≦ a ≦ 200.)
One-terminal-reactive organopolysiloxane having one alkenyl group at the terminal represented by the formula: 10 to 35 parts by mass of component (A) based on the total amount of component (A) and component (B) The following average composition formula (2):
R ³ _b SiO _{(4-b) / 2} ... (2)
(In the formula, R ³ is independently an unsubstituted or substituted monovalent hydrocarbon group, and b is a positive number satisfying 0 <b ≦ 3.) Organopolysiloxane having an alkenyl group: 65 to 90 parts by weight of component (B) based on 100 parts by weight of total of components (A) and (B) (C) Average compositional formula (3) below:
R ⁴ _c H _d SiO _{(4-cd) / 2}・ ・ ・ (3)
(Wherein R ⁴ is independently an unsubstituted or substituted monovalent hydrocarbon group not containing an alkenyl group, and c and d are 0.7 ≦ c ≦ 2.1, 0.001 ≦ d ≦ 1. 0 and a positive number satisfying 0.8 ≦ c + d ≦ 3.0.)
An organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms in one molecule represented by the following formula: relative to all alkenyl groups in the components (A) and (B), The amount by which the number of hydrogen atoms bonded to silicon atoms is 0.5 to 5.0 times,
(D) a platinum group metal-based catalyst: a heavy release composition for a release sheet containing an effective amount,
(B) a component having at least two alkenyl groups in one molecule, an organopolysiloxane resin (B-1) having a three-dimensional network structure, which is a waxy or solid at 25 ° C .; A combination of a liquid or linear or branched organopolysiloxane (B-2) having at least two alkenyl groups at a terminal, comprising a component (B-1) and a component (B-2). Mass ratio (B-2) / (B-1) is 0.1 to 0.5, and
The component (C) has an organohydrogenpolysiloxane (C-1) having a hydrogen atom bonded to a silicon atom in a side chain, and has a hydrogen atom bonded to a silicon atom at a terminal and has no hydrogen atom in a side chain. A release sheet comprising a combination of an organohydrogenpolysiloxane (C-2) and a mass ratio (C-2) / (C-1) of the component (C-1) to the component (C-2) of 1 to 5. Heavy release composition. The component (B-1) has the following average composition formula (4):
_{^{(R 6 3 SiO 1/2) e}} (R 5 R 6 2 SiO 1/2) f (R 5 R 6 SiO) g (R 6 2 SiO) h (R 5 SiO 3/2) i (R 6 SiO _3/2 ) _j (SiO _4/2 ) _k・ ・ ・ (4)
(Wherein, R ⁵ independently represents an alkenyl group, R ⁶ independently represents an unsubstituted or substituted monovalent hydrocarbon group containing no alkenyl group, provided that at least 80 mol% of all R ⁶ is a methyl group. And e, f, g, h, i, j and k are numbers satisfying e ≧ 0, f ≧ 0, g ≧ 0, h ≧ 0, i ≧ 0, j ≧ 0 and k ≧ 0, respectively. Yes, provided that f + g + i> 0, i + j + k> 0, (e + f + g + h) / (i + j + k) <1.3, and a number that satisfies e + f + g + h + i + j + k = 1.)
The heavy release for a release sheet according to claim 1, which is an organopolysiloxane resin having at least two alkenyl groups in one molecule, being waxy or solid at 25 ° C, and having a three-dimensional network structure. Composition. The above (B-2) is represented by the following average composition formula (5):
_{^{(R 8 3 SiO 1/2) l}} (R 7 R 8 2 SiO 1/2) m (R 8 2 SiO) n (R 8 SiO 3/2) p (SiO 4/2) q ··· (5 )
(Wherein, R ⁷ independently represents an alkenyl group, R ⁸ independently represents an unsubstituted or substituted monovalent hydrocarbon group containing no alkenyl group, provided that at least 80 mol% of all R ⁸ is a methyl group. Yes, l, m, n, p and q are numbers satisfying l ≧ 0, m> 0, n ≧ 0, p ≧ 0 and q ≧ 0, respectively, provided that n + p + q> 0 and p + q <0. 1 and a number satisfying l + m + n + p + q = 1.)
3. The heavy release composition for a release sheet according to claim 1, wherein the composition is a linear or branched organopolysiloxane having at least two alkenyl groups at terminals, which is liquid at 25 ° C. The above component (C-1) has the following average composition formula (6):
_{^{(R 9 3 SiO 1/2) r}} (R 9 2 HSiO 1/2) s (R 9 HSiO) t (R 9 2 SiO) u (HSiO 3/2) v (R 9 SiO 3/2) w ( SiO _4/2 ) _{x ・ ・ ・} (6)
(Wherein, R ⁹ independently represents an unsubstituted or substituted monovalent hydrocarbon group containing no alkenyl group, and r, s, t, u, v, w, and x are respectively r ≧ 0, s ≧ 0, t ≧ 0, u ≧ 0, v ≧ 0, w ≧ 0 and x ≧ 0, provided that t + v> 0 and s + t + u + v + w + x + y = 1.)
The heavy release composition for a release sheet according to any one of claims 1 to 3, which is an organohydrogenpolysiloxane having a hydrogen atom bonded to a silicon atom in a side chain represented by the following formula: The component (C-2) has the following average composition formula (7):
(R ¹⁰ ₃ SiO _1/2 ) _α (R ¹⁰ ₂ HSiO _1/2 ) _β (R ¹⁰ ₂ SiO) _γ (R ¹⁰ SiO _3/2 ) _δ (SiO _4/2 ) _ε (7)
(Wherein, R ¹⁰ independently represents an unsubstituted or substituted monovalent hydrocarbon group containing no alkenyl group, and α, β, γ, δ, and ε are α ≧ 0, β> 0, γ, respectively) It is a number that satisfies ≧ 0, δ ≧ 0, and ε ≧ 0, provided that γ + δ + ε> 0, δ + ε <0.1, and α + β + γ + δ + ε = 1.)
5. The heavy release composition for a release sheet according to claim 1, wherein the organohydrogenpolysiloxane has a hydrogen atom bonded to a silicon atom at a terminal and has no hydrogen atom in a side chain. 6. .   The heavy release composition for a release sheet according to any one of claims 1 to 5, wherein the viscosity at 25 ° C is 50 to 2,000 mPa · s.   A release sheet having a sheet-like substrate and a cured film of the heavy release composition for a release sheet according to any one of claims 1 to 6 on one or both surfaces of the substrate.   The peeling sheet according to claim 7, wherein a peeling force measured at an angle of 180 ° and a peeling speed of 0.3 m / min by attaching a Tesa 7475 tape to the cured film is 5 to 20 N / 25 mm.

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