JP2003105089A - Organohydrogenpolysiloxane mixture and repellent cured-film forming silicone composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organohydrogenpolysiloxane mixture which is useful as a crosslinking agent and an adhesion improver of an addition-reaction curable silicone composition, and a releasable cured-film forming silicone composition which can form a releasable cured-film excellent in adhesion to the surface of various base materials. SOLUTION: There are provided an organohydrogenpolysiloxane mixture which comprises a partially branched, straight-chain organohydrogen polysiloxane having two or more silicon-atom-bonding hydrogen atoms in the molecule, has a viscosity at 25 deg.C of 80-700 mPa.s, and has a dispersion degree (weight average molecular weight/number average molecular weight) of 2.0-10.0, and a releasable cured-film forming silicone composition composed primarily of (A) an organopolysiloxane having a viscosity at 25 deg.C of 40 mPa.s or more and having two or more alkenyl groups in the molecle, (B) the organohydrogenpolysiloxane mixture, and (C) an addition-reaction accelerating catalyst.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an organohydrogenpolysiloxane mixture and a peelable cured film-forming silicone composition. Specifically, an organohydrogenpolysiloxane mixture useful as a cross-linking agent for an addition reaction-curable silicone composition, and an adhesive substance having excellent adhesion to the surface of various paper materials, synthetic resin films, metal foils, and other base materials. The present invention relates to a releasable cured film-forming silicone composition capable of forming a releasable cured film.

[0002]

2. Description of the Related Art Conventionally, paper, cardboard paper, laminate
Base materials such as paper, synthetic resin film, cloth, synthetic fiber, metal foil, etc.
Apply a peelable cured film-forming silicone composition to the surface of the
By applying a cloth and curing it,
It is known that a cured film with good peelability can be obtained.
There is. Such a peelable cured film-forming silicone composition
As the product, an alkenyl group-containing organopolysiloxane and a ke
Organohydrogen poly containing hydrogen atoms bonded to iodine atoms
Various addition reactions mainly composed of siloxane and platinum catalyst
A curable silicone composition has been proposed and used there
As an organohydrogenpolysiloxane
Usually has a viscosity of about 5 centipoise to 70 mm ²/ S
Uses single compound with low viscosity and narrow molecular weight distribution
(For example, Japanese Patent Laid-Open No. 2-145649)
JP-A-7-258606 and 2000-160.
No. 101, JP-A 2000-160102
See example). However, such an organohide
Addition-reaction-curable silicone using rhogen polysiloxane
The corn composition has sufficient adhesion to the substrate after curing.
Not particularly on a synthetic resin film or clay-coated paper.
There was a problem that it was difficult to wear.

[0003]

The present inventors have arrived at the present invention as a result of extensive studies to solve the above problems. That is, an object of the present invention is to form an organohydrogenpolysiloxane mixture which is useful as a crosslinking agent and an adhesion improver for addition reaction curable silicone compositions, and to form a peelable cured film having excellent adhesion on various substrate surfaces. It is to provide a peelable cured film-forming silicone composition that can be used.

[0004]

The present invention provides 2 in 1 molecule.
Consisting of a partially branched linear organohydrogenpolysiloxane having at least one silicon-bonded hydrogen atom, a viscosity at 25 ° C. of 80 to 700 mPa · s, and a dispersity (weight average molecular weight / number average molecular weight). 2.0
Organohydrogenpolysiloxane mixture characterized by being 1 to 10.0, and (A) the viscosity at 25 ° C. is 40 mPa · s or more, and 2 in 1 molecule.
An organopolysiloxane having at least two alkenyl groups, (B) a partially branched linear organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms in one molecule, and a viscosity at 25 ° C. of 80.
To 700 mPa · s, and the degree of dispersion (weight average molecular weight /
A number average molecular weight) of the organohydrogenpolysiloxane mixture is 2.0 to 10.0, and (C) an addition reaction accelerating catalyst as a main component.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION First, the organohydrogenpolysiloxane mixture of the present invention will be described. The organohydrogenpolysiloxane mixture of the present invention is
Having two or more silicon-bonded hydrogen atoms in one molecule,
It is a partially branched linear organohydrogenpolysiloxane which is a mixture of different molecular weights. The organohydrogenpolysiloxane usually contains a siloxane unit represented by the formula: RSiO _3/2 . In the above formula, R is an alkyl group or an aryl group, and examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, and a phenyl group. It is preferable that 1 to 20 siloxane units represented by the above formula are contained in one molecule.
More preferably, it is 10. And 2 of the mixture
The viscosity at 5 ° C. is 80 to 700 mPa · s, preferably 100 to 500 mPa · s, and more preferably 100 to 300 mPa · s. This mixture has a wide molecular weight distribution from the low molecular weight region to the high molecular weight region,
The dispersity (weight average molecular weight / number average molecular weight) is 2.0.
The range is from 10.0 to 1.0, the range from 2.0 to 6.0 is preferable, and the range from 2.5 to 5.5 is more preferable. In the organohydrogenpolysiloxane, examples of the group bonded to a silicon atom other than a hydrogen atom include a hydroxyl group in addition to the above-described alkyl group and aryl group. Specific examples include organohydrogenpolysiloxanes represented by the following general formula. (RHSiO _2/2 ) _x (RSiO _3/2 ) _y (R ₂ Si
O _2/2 ) _z (R ₃ SiO _1/2 ) _{w In the} above formula, R is the same as above. x is a number of 2 or more, y and w are numbers of 1 or more, and z is a number of 0 or more. (X + y + z + w) is 2
The number is such that the viscosity at 5 ° C. is 80 to 700 mPa · s. Incidentally, y is preferably 1 to 20,
1-10 is more preferable. (Y / x) is 0.01 to 0.1
It is preferably 0, and more preferably 0.01 to 0.06. (Z / x) is preferably 0.10 or less, and more preferably 0.08 or less.

The organohydrogenpolysiloxane mixture of the present invention comprises, for example, a silicon atom-bonded hydrogen atom-containing organohydrogensiloxane cyclic compound and a trimethylsiloxy group-capped dimethylsiloxane oligomer in the presence of an acidic catalyst at 1 to 30 ° C. After reacting for 3 hours,
Produced by a method of heating to 70 to 100 ° C. and reacting for 1 to 24 hours, or a method of heating a linear low-polymerization degree organohydrogenpolysiloxane at 70 to 100 ° C. for 1 to 24 hours in the presence of an acidic catalyst. can do. In these methods, due to the trace amount of water present in the raw material, R
A part of the silicon atom-bonded hydrogen atoms in the HSiO unit becomes a silanol group, and the generated R (HO) SiO unit and RHS
It is presumed that dehydrogenative condensation occurs with iO units to form RSiO _3/2 units. Further, water may be added during the heating reaction, and by adding water, a higher viscosity organohydrogenpolysiloxane mixture can be obtained.

Such an organohydrogenpolysiloxane mixture of the present invention is useful as a cross-linking agent for addition reaction-curable silicone compositions, and is characterized in that it acts as a cross-linking agent with excellent adhesion. The mixture of the present invention can be used in both solvent type and solventless type addition reaction curable silicone compositions. The term "addition reaction curing type" as used in the present invention means that an alkenyl group-containing organopolysiloxane and an organohydrogenpolysiloxane undergo a hydrosilylation reaction in the presence of an addition reaction accelerating catalyst.

Next, the peelable cured film-forming silicone composition of the present invention will be described. (A) The organopolysiloxane having two or more alkenyl groups in one molecule is the main ingredient of the composition of the present invention, and is usually represented by the average unit formula: R ¹ _a SiO _{(4-a) / 2} . In the above formula, R ¹ is a monovalent hydrocarbon group, an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group; a vinyl group,
Alkyl groups such as allyl group, butenyl group, pentenyl group, hexenyl group; aryl groups such as phenyl group, tolyl group, xylyl group; aralkyl groups such as benzyl group, phenethyl group; 3-chloropropyl group, 3,3,3 -A halo-substituted alkyl group such as a trifluoropropyl group is exemplified. a is a number from 1.95 to 2.05. The molecular structure is not particularly limited, and examples thereof include linear, cyclic, network, and partially branched linear, and preferably linear. When the molecular structure is linear, examples of the terminal group of the molecular chain include trimethylsiloxy group, dimethylvinylsiloxy group, dimethylphenylsiloxy group and dimethylhydroxysiloxy group. The viscosity at 25 ° C is 40 mPas.
・ S or more, the upper limit of which is a raw rubber-like viscosity. This is because if it is less than 40 mPa · s, the resulting peelable cured film-forming silicone composition penetrates too much into the substrate. When the composition of the present invention is used as a solventless type, the viscosity of the component (A) is 40 to 10,
It is preferably in the range of 000 mPa · s, and 100
The range of up to 5,000 mPa · s is more preferable. When the composition of the present invention is used as a solvent type, 100,
It is preferably from 000 mPa · s to a raw rubber-like viscosity, more preferably from 500,000 mPa · s to a raw rubber-like viscosity.

As the component (A), a dimethylpolysiloxane capped with dimethylvinylsiloxy groups at both ends of the molecular chain, a dimethylvinylsiloxy group-capped dimethylsiloxane / methylvinylsiloxane copolymer capped with both ends of the molecular chain, and a dimethylvinylsiloxy group at both ends of the molecular chain are used. Blocked dimethyl siloxane / methyl phenyl siloxane copolymer, molecular chain both ends trimethylsiloxy group blocked methyl vinyl polysiloxane, molecular chain both ends trimethyl siloxy group blocked dimethyl siloxane / methyl vinyl siloxane copolymer, molecular chain both ends trimethyl siloxy group blocked Dimethylsiloxane methyl (5
-Hexenyl) siloxane copolymer, dimethylhexenylsiloxy group-capped dimethylsiloxane / methyl (5-hexenyl) siloxane copolymer at both molecular chain ends, dimethylvinylsiloxy group-capped dimethylsiloxane / methylvinylsiloxane / methylphenylsiloxane at both molecular chain ends Examples thereof include a copolymer, a dimethylhydroxysiloxy group-blocked methylvinylpolysiloxane having molecular chain terminals at both ends, and a dimethylhydroxysiloxy group-blocked dimethylsiloxane / methylvinylsiloxane copolymer having a molecular chain terminals at both ends.

The (B) organohydrogenpolysiloxane mixture is as described above. The blending amount of the component (B) is preferably 0.5 to 20 parts by weight, more preferably 1 to 10 parts by weight, based on 100 parts by weight of the component (A). This is because if the compounding amount of the component (B) is less than 0.5 parts by weight, the composition of the present invention may be insufficiently cured, and if it exceeds 20 parts by weight, the releasability of the cured film may decrease. Because there is.

The (C) addition reaction promoting catalyst is for curing the composition of the present invention by promoting the addition reaction between the alkenyl group in the component (A) and the silicon atom-bonded hydrogen atom in the component (B). Of the catalyst. Platinum-based catalysts are preferable as the addition reaction accelerating catalyst, and chloroplatinic acid, an alcohol solution of chloroplatinic acid, a complex of chloroplatinic acid and an olefin, a complex of chloroplatinic acid and vinylsiloxane, a chloroplatinic acid and ketones are used. Examples of the complex are platinum, alumina fine powder supporting platinum, silica fine powder supporting platinum, and platinum black. The blending amount of the component (C) is not particularly limited as long as it is a catalytic amount, but (A)
The amount is preferably such that platinum metal is 1 to 1,000 ppm with respect to the components.

The peelable cured film-forming silicone composition of the present invention contains the above-mentioned components (A) to (C) as the main components, but an addition reaction inhibitor is added to improve the storage stability at room temperature. It is preferable. Specific examples of the addition reaction inhibitor include 3-methyl-1-butyn-3-ol, 3,5-
Dimethyl-1-hexyn-3-ol, 3-methyl-1
-Penten-3-ol, alkynyl alcohols such as phenylbutynol; 3-methyl-3-penten-1-yne, 3,5-dimethyl-1-hexyne-3-yne, benzotriazole, 1-ethynyl-1- Examples are cyclohexanol and methylvinylsiloxane cyclic compounds. The addition amount of the addition reaction inhibitor is usually in the range of 0.001 to 5 parts by weight with respect to 100 parts by weight of the component (A).

Further, the composition of the present invention may optionally contain
A peeling resistance adjusting agent, a heat resistance additive, an organic resin powder, a photosensitizer, a dye, a pigment, and a thickening agent such as silica fine powder may be added. Further, a low-viscosity organohydrogenpolysiloxane having a viscosity at 25 ° C. of less than 80 mPa · s may be used in combination. The organic solvent used when the composition of the present invention is used as a solvent type is not particularly limited as long as it can uniformly dissolve the composition of the present invention. Specifically, aromatic hydrocarbons such as benzene, toluene, xylene; aliphatic hydrocarbons such as pentane, hexane, heptane; trichloroethylene, perchloroethylene, trifluoromethylbenzene, 1,3-bis (trifluoro) Examples thereof include halogenated hydrocarbons such as methyl) benzene and methylpentafluorobenzene; ethyl acetate, methyl ethyl ketone, and methyl isobutyl ketone. On the other hand, when the composition of the present invention is a solventless type, the viscosity at 25 ° C. is 50 to 5.0.
00 mPa · s is preferable, and 100 to 2,000
The range of 0 mPa · s is more preferable.

The curing conditions for the composition of the present invention are not particularly limited, but it is generally preferable to heat-cure in the temperature range of 50 to 200 ° C. Further, heating and ultraviolet irradiation may be used together.

The releasable cured film-forming silicone composition of the present invention as described above is used for the surface of various base materials such as paper, cardboard paper, clay-coated paper, laminated paper, synthetic resin film, cloth, synthetic fiber and metal foil. In addition, it has a feature of forming a peelable cured film having an appropriate peeling resistance to an adhesive substance and a good residual adhesion rate. In particular, it has an advantage that it firmly adheres to a synthetic resin film such as polyethylene terephthalate or clay-coated paper, which has been difficult with conventional silicone-based release agents. The substrate having such a peelable cured film of the composition of the present invention can be used for process paper, asphalt paper, tape, label and the like.

[0016]

EXAMPLES The present invention will be described in detail below with reference to examples.
In the examples, the viscosity is a value measured by a rotational viscometer at 25 ° C., and parts are parts by weight. Further, the curing adhesion of the peelable cured film-forming silicone composition to the substrate, the peeling resistance value of the cured film, and the residual adhesion rate of the adhesive substance were measured by the following methods.

○ Curing adhesiveness A peelable cured film-forming silicone composition was applied to a polyethylene terephthalate film at a coating amount of 0.5 g / m ² , and then this was heated in a hot air circulating oven at 140 ° C. It was heated for 30 seconds to form a cured film. After this was left for 48 hours under the conditions of a temperature of 40 ° C. and a humidity of 90%, it was strongly rubbed with a finger to measure the presence or absence of the film falling off. ○ When the film is firmly attached without falling off from the film
When the film was found to have fallen off, it was marked with x.

○ Peeling resistance value of cured film The amount of the peelable cured film-forming silicone composition applied was 1.
It was coated on the surface of polyethylene laminated paper so as to be 0 g / m ² , and then it was placed in a hot air circulation oven for 1
A cured film was formed by heating at 60 ° C for 30 seconds. Acrylic adhesive [manufactured by Toyo Ink Mfg. Co., Ltd., trade name Olivine BPS5127] is applied to the obtained cured film,
It was heated and dried at 70 ° C. for 2 minutes in a hot air circulation type oven.
Then, a piece of laminated paper was attached to this, and the piece was allowed to stand for 24 hours at a temperature of 25 ° C. and a humidity of 60% while applying a load of 20 g / cm ² . After 24 hours, the laminated paper was pulled at an angle of 180 degrees using Tensilon, and the force (mN) required for peeling was measured. The sample width was all 5 cm.

Residual adhesion rate of tacky substance The amount of the peelable cured film-forming silicone composition applied is 1.
It was coated on the surface of polyethylene laminated paper so as to have a cured film of 0 g / m ² . On the surface of this film,
20 g / cm ^{2 of} adhesive tape [Nitto Denko Corporation, trade name: Knit-polyester adhesive tape 31B]
Was applied and the sample was aged at 70 ° C. for 20 hours. Next, peel off the adhesive tape, attach the peeled adhesive tape to a stainless steel plate, and apply a load of 20 g / cm ² to 25 ° C.
After being left for 30 minutes at 80 ° C., the adhesive tape was pulled under the conditions of an angle of 180 ° and a speed of 0.3 m / min, and the force (gf) required for peeling was measured. Further, as a blank test, an adhesive tape [manufactured by Nitto Denko Corporation, trade name:
Knit-polyester pressure-sensitive adhesive tape 31B] was laminated in the same manner as above, and the force (gf) required for peeling off this pressure-sensitive adhesive tape was measured in the same manner as above. From these measured values, the residual adhesion rate (%) was calculated according to the following formula.

[Formula 1]

[0020]

Example 1 Tetramethyltetracyclosiloxane 14
5.65 parts with 4.35 parts of hexamethyldisiloxane,
After 4.05 parts of activated clay was added and mixed and reacted at 40 ° C. for 2 hours, the temperature was further raised to 80 ° C. and reacted for 10 hours. After cooling, filtration was performed to obtain a methylhydrogenpolysiloxane mixture having a viscosity of 150 mPa · s. When the obtained methyl hydrogen polysiloxane mixture was subjected to nuclear magnetic resonance spectrum analysis (hereinafter, NMR analysis),
The end of the molecular chain is blocked with a trimethylsiloxy group, and the main chain has the formula:

[Chemical 1] (Y / x was 0.03) It was found that the mixture was a mixture of linear methylhydrogenpolysiloxanes having a branched part in the molecule, which consisted of siloxane units. In addition, the degree of dispersion (weight average molecular weight / number average molecular weight) by gel permeation chromatography analysis (hereinafter, GPC analysis) was 2.87.

[0021]

Example 2 Tetramethyltetracyclosiloxane 14
5.65 parts with 4.35 parts of hexamethyldisiloxane,
After 4.05 parts of activated clay was added and mixed and reacted at 40 ° C for 2 hours, the temperature was further raised to 90 ° C and reacted for 10 hours. After cooling, filtration was performed to obtain a methylhydrogenpolysiloxane mixture having a viscosity of 250 mPa · s. NMR analysis of the resulting methyl hydrogen polysiloxane mixture
Analysis revealed that the end of the molecular chain was blocked with a trimethylsiloxy group, and the main chain had the formula:

[Chemical 2] (Y / x was 0.04.) It was found to be a mixture of linear methyl methyl polysiloxanes having a branched part in the molecule, which consisted of siloxane units. The degree of dispersion (weight average molecular weight / number average molecular weight) by GPC analysis was 5.38.

[0022]

[Example 3] 100 parts of a raw rubber-like molecular chain end-capped trimethylsiloxy group-blocked dimethylsiloxane / methylvinylsiloxane copolymer (vinyl group content 0.9% by weight), the viscosity obtained in Example 1 was 150 mPa · s. 2 parts of methyl hydrogen polysiloxane mixture, chloroplatinic acid and 1,
An amount of a complex salt with 3-divinyltetramethyldisiloxane such that the amount of platinum metal is 200 ppm, 3-methyl-1-
1 part of butyn-3-ol and 1957 parts of toluene were mixed to prepare a solvent-type peelable cured film-forming silicone composition. The cured adhesiveness of the obtained silicone composition to a substrate, the peeling resistance value of the cured film, and the residual adhesion rate of the adhesive substance were measured. The results are shown in Table 1.

[0023]

[Example 4] 100 parts of a raw rubber-like molecular chain end-capped trimethylsiloxy group-terminated dimethylsiloxane / methylvinylsiloxane copolymer (vinyl group content 0.9% by weight), the viscosity obtained in Example 2 was 250 mPa · s. 2 parts of methyl hydrogen polysiloxane mixture, chloroplatinic acid and 1,
An amount of a complex salt with 3-divinyltetramethyldisiloxane such that the amount of platinum metal is 200 ppm, 3-methyl-1-
1 part of butyn-3-ol and 1957 parts of toluene were mixed to prepare a solvent-type peelable cured film-forming silicone composition. The cured adhesiveness of the obtained silicone composition to a substrate, the peeling resistance value of the cured film, and the residual adhesion rate of the adhesive substance were measured. The results are shown in Table 1.

[0024]

Comparative Example 1 In Example 3, the viscosity is 150 mPa · s.
Instead of the methylhydrogenpolysiloxane mixture described above, a methylhydrogenpolysiloxane with a viscosity of 25 mPa · s and a dispersity of 1.41 blocked at both ends of the molecular chain by trimethylsiloxy groups (manufactured by Toray Dow Corning Silicone Co., Ltd .; product name SP7297) A solvent-based peelable cured film-forming silicone composition was prepared in the same manner as in Example 3 except that The cured adhesiveness of the obtained silicone composition to a substrate, the peeling resistance value of the cured film, and the residual adhesion rate of the adhesive substance were measured. The results are shown in Table 1.

[0025]

Example 5 Raw rubber-like molecular chain blocked at both ends with trimethylsiloxy groups Dimethylsiloxane / methylhexenylsiloxane copolymer (hexenyl group content 0.5% by weight) 10
0 part, 2 parts of the methylhydrogenpolysiloxane mixture having a viscosity of 150 mPa · s obtained in Example 1, a complex salt of chloroplatinic acid and 1,3-divinyltetramethyldisiloxane so that the amount of platinum metal is 200 ppm. 1 part of 3-methyl-1-butyn-3-ol and 1957 parts of toluene were mixed to prepare a solvent-type peelable cured film-forming silicone composition. The cured adhesiveness of the obtained silicone composition to a substrate, the peeling resistance value of the cured film, and the residual adhesion rate of the adhesive substance were measured. The results are shown in Table 1.

[0026]

[Comparative Example 2] In Example 5, the viscosity was 150 mPa · s.
Instead of the methylhydrogenpolysiloxane mixture described above, a methylhydrogenpolysiloxane with a viscosity of 25 mPa · s and a dispersity of 1.41 blocked at both ends of the molecular chain by trimethylsiloxy groups (manufactured by Toray Dow Corning Silicone Co., Ltd .; product name SP7297) A solvent-based peelable cured film-forming silicone composition was prepared in the same manner as in Example 5 except that The cured adhesiveness of the obtained silicone composition to a substrate, the peeling resistance value of the cured film, and the residual adhesion rate of the adhesive substance were measured. The results are shown in Table 1.

[0027]

[Example 6] 100 parts of a dimethylhexenylsiloxy group-capped dimethylsiloxane / methylhexenylsiloxane copolymer having a viscosity of 400 mPa · s at both ends of the molecular chain (hexenyl group content 1.0% by weight), the viscosity obtained in Example 2 Two
3 parts of 50 mPa · s methylhydrogenpolysiloxane mixture, a complex salt of chloroplatinic acid and 1,3-divinyltetramethyldisiloxane, in an amount such that the amount of platinum metal is 200 ppm, 1-ethynyl-1-cyclohexanol 1
The parts were mixed to prepare a solvent-free peelable cured film-forming silicone composition having a viscosity of 390 mPa · s. The cured adhesiveness of the obtained silicone composition to a substrate, the peeling resistance value of the cured film, and the residual adhesion rate of the adhesive substance were measured. The results are shown in Table 1.

[0028]

[Comparative Example 3] In Example 6, the viscosity was 250 mPa · s.
Instead of the methylhydrogenpolysiloxane mixture described above, a methylhydrogenpolysiloxane with a viscosity of 25 mPa · s and a dispersity of 1.41 blocked at both ends of the molecular chain by trimethylsiloxy groups (manufactured by Toray Dow Corning Silicone Co., Ltd .; product name SP7297) A solvent-free peelable cured film-forming silicone composition was prepared in the same manner as in Example 6 except that was added. The cured adhesiveness of the obtained silicone composition to a substrate, the peeling resistance value of the cured film, and the residual adhesion rate of the adhesive substance were measured. The results are shown in Table 1.

[0029]

[Table 1]

[0030]

The organohydrogenpolysiloxane mixture of the present invention is a mixture of linear organohydrogenpolysiloxanes having a branch in a part of the molecule, and has a higher viscosity than conventional organohydrogenpolysiloxanes. Since it has a high degree of dispersion, it is useful as a cross-linking agent for an addition reaction-curable silicone composition, and in particular has a feature of acting as a cross-linking agent having excellent adhesion. Further, since the peelable cured film-forming silicone composition of the present invention contains the organohydrogenpolysiloxane mixture of the present invention as a crosslinking agent, a peelable cured film excellent in adhesion to various substrate surfaces can be obtained. It has the feature of forming.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4J002 CP04X CP12W DA116 DE176                       DE186 GH01                 4J035 BA04 CA01 CA02 EA01 EB10                       LA03 LB01

Claims (6)

[Claims] 1. A partially branched linear organohydrogenpolysiloxane having two or more silicon-bonded hydrogen atoms in one molecule, having a viscosity at 25 ° C. of 80 to 700 mPa · s and a dispersity degree. (Weight average molecular weight / number average molecular weight) is 2.0-10.0, Organohydrogen polysiloxane mixture characterized by the above-mentioned. 2. A partially branched linear organohydrogenpolysiloxane having two or more silicon-bonded hydrogen atoms in one molecule is represented by the formula: RSiO _3/2 (wherein R is
Is an alkyl group or an aryl group. ) The organohydrogenpolysiloxane mixture according to claim 1, which is an organohydrogenpolysiloxane containing siloxane units. 3. An organohydrogenpolysiloxane having a siloxane unit represented by the formula: RSiO _3/2 (wherein R is an alkyl group or an aryl group) has the general formula: (RHSiO _2/2 ). _x (RSiO _3/2 ) _y (R ₂ SiO
_2/2 ) _z (R ₃ SiO _1/2 ) _w [wherein R is the same as above, x is a number of 2 or more, y and w are numbers of 1 or more, and z is 0 or more. And (x + y + z + w) has a viscosity of 80 at 25 ° C.
It is a number such that it becomes ~ 700 mPa · s. ] The organohydrogen polysiloxane mixture of Claim 2 which is an organohydrogen polysiloxane represented by these. 4. The organohydrogenpolysiloxane mixture according to any one of claims 1 to 3, which is a cross-linking agent for an addition reaction-curable silicone composition. 5. The organohydrogenpolysiloxane mixture according to claim 4, wherein the addition reaction curable silicone composition is a peelable cured film-forming composition. 6. (A) The viscosity at 25 ° C. is 40 mPas.
An organopolysiloxane of s or more and having two or more alkenyl groups in one molecule, (B) a partially branched straight-chain organohydrogen having two or more silicon-bonded hydrogen atoms in one molecule It is made of polysiloxane, has a viscosity at 25 ° C. of 80 to 700 mPa · s, and a dispersity (weight average molecular weight / number average molecular weight) of 2.0.
A peelable cured film-forming silicone composition, which comprises an organohydrogenpolysiloxane mixture of 1 to 10.0 and (C) an addition reaction accelerating catalyst as main components.