KR102177260B1 - Silicone adhesive composition - Google Patents

Abstract

The present invention relates to a silicone adhesive composition containing a first organopolysiloxane, a second organopolysiloxane, a first diorganopolysiloxane, a second diorganopolysiloxane, a diorgano hydrogen siloxy-terminated polyorganosiloxane, and a catalyst. The silicone adhesive composition according to the present invention is very suitable as an adhesive for an image display device or a silicone pressure-sensitive adhesive of various fields.

Description

Silicone adhesive composition {SILICONE ADHESIVE COMPOSITION}

The present invention relates to a silicone pressure-sensitive adhesive composition having excellent adhesion, high active ingredient content and good fluidity.

In order to improve the visibility or impact resistance of an image display device, there is an increasing demand for an adhesive material used between a window glass and a touch screen panel (TSP) sensor glass as an image display device protection unit. As a conventional adhesive, a room temperature curing liquid silicone rubber composition or an OCA film (Optically Clear Adhesive Film) as OCR (Optically Clear Resin) was used.

However, in the case of OCR, since the coating process or the laminating process is complicated, the quality of the processed product is greatly influenced by the device or process conditions, and there is a limitation in that it is difficult to rework due to the peeling of the OCR cured product when a defect occurs in the processed product. As an alternative to this, an OCA film has been proposed, but the OCA film generally has lower adhesion than OCR, and thus lacks fixation of the adherend, so that the adherend is detached or whitened in a high temperature and high humidity environment.

On the other hand, a silicone adhesive with high adhesive strength is generally used for labels and the like. Specifically, Japanese Patent Registration No. 2,878,932 (Patent Document 1) includes an organopolysiloxane containing a vinyl group, an organohydrogen polysiloxane, an organosilicon compound having a BO-Si bond, and a platinum-based catalyst, and adhesion at high temperatures This improved silicone pressure-sensitive adhesive composition is disclosed. However, as in Patent Document 1, the silicone pressure-sensitive adhesive composition having a high adhesive strength has a high viscosity of the silicone component, so that dilution using a large amount of organic solvent is required to impart good fluidity. In addition, when the pressure-sensitive adhesive layer is formed with a silicone pressure-sensitive adhesive composition diluted with an organic solvent as described above, there is a limitation in that it is difficult to obtain a thick film having a thickness of 100 μm or more and having a uniform thickness.

As an alternative to this, a solvent-free silicone adhesive having good flowability without being diluted with an organic solvent has been proposed. Specifically, Japanese Patent No. 5,130,995 (Patent Document 2) includes polyorganosiloxanes containing alkenyl groups, polyorganohydrosiloxanes containing SiH groups, polydiorganosiloxanes containing alkenyl groups at both ends, and polyorganosiloxanes containing SiH groups at both ends. Disclosed is a solvent-free silicone pressure-sensitive adhesive composition comprising a diorganosiloxane and a platinum-based catalyst. However, as in Patent Document 2, a silicone pressure-sensitive adhesive composition that is not diluted with an organic solvent and has good fluidity can produce a thick film having a thickness of 100 μm or more and having a uniform thickness, but due to the lack of adhesion of the prepared thick film, it is used for OCA. There are limitations that are difficult to apply.

Therefore, it is possible to form a thick film having a thickness of 100 μm or more and having a uniform thickness, and there is a need for research and development on a silicone pressure-sensitive adhesive composition having excellent adhesion, low use of organic solvents and good fluidity.

Japanese Patent Registration No. 2,878,932 (published on January 13, 1995) Japanese Patent No. 5,130,995 (published on November 13, 2008)

Accordingly, the present invention is to provide a silicone pressure-sensitive adhesive composition having a thickness of 100 μm or more and capable of forming a uniform thick film, excellent adhesion, low use of organic solvents, and good fluidity.

The present invention comprises a first organopolysiloxane, a second organopolysiloxane, a first diorganopolysiloxane, a second diorganopolysiloxane, a diorgano hydrogen siloxy-terminated polyorganosiloxane and a catalyst,

The first organopolysiloxane is an R ¹ ₃ SiO _1/2 unit (wherein R ¹ is a substituted or unsubstituted C _1-10 alkyl group, or a hydroxyl group, and R ¹ may be the same or different, respectively.) Contains SiO ₂ units,

The second organopolysiloxane is R ² R ³ ₂ SiO _1/2 unit (in the formula, R ² is a substituted or unsubstituted C _2-10 alkenyl group, and R ³ is a substituted or unsubstituted C _1-10 alkyl group ), R ⁴ ₃ SiO _1/2 unit (in the formula, R ⁴ is a substituted or unsubstituted C _1-10 alkyl group.) and SiO ₂ units,

The first diorganopolysiloxane and the second diorganopolysiloxane have at least two alkenyl groups in one molecule,

The first diorganopolysiloxane has a viscosity at 25° C. lower than that of the second diorganopolysiloxane, providing a silicone pressure-sensitive adhesive composition.

The silicone pressure-sensitive adhesive composition according to the present invention uses a diorganopolysiloxane containing an alkenyl group and a diorgano hydrogen siloxy-terminated polyorganosiloxane to form a high molecular weight siloxane through a chain extension reaction during heat curing to form a thick film with a thickness of 100 μm or more. Can be manufactured in thickness. In addition, the silicone pressure-sensitive adhesive composition uses a high-viscosity diorganopolysiloxane to appropriately adjust the viscosity, so that the organic solvent content is small and the fluidity is good. Further, the cured product prepared from the silicone pressure-sensitive adhesive composition has less discoloration due to high temperature and/or high humidity environment, or UV irradiation, and maintains transparency or adhesive strength, and is excellent in long-term reliability. In addition, the cured product prepared from the silicone pressure-sensitive adhesive composition has adequate cohesiveness and strength, and can be removed without leaving a residue on the adherend when peeling from the adherend, and thus excellent reworkability. Due to the above-described effects, the silicone pressure-sensitive adhesive composition according to the present invention is very suitable as a pressure-sensitive adhesive for an image display device or a silicone pressure-sensitive adhesive for various fields.

Hereinafter, the present invention will be described in detail.

The "number average molecular weight" used herein is measured by a conventional method known in the art, and can be measured, for example, by a gel permeation chromatograph (GPC) method. Further, functional values such as'hydroxyl value' and'vinyl group content' may be measured by a method well known in the art, and may represent a value measured by, for example, a titration method.

The silicone pressure-sensitive adhesive composition according to the present invention includes a first organopolysiloxane, a second organopolysiloxane, a first diorganopolysiloxane, a second diorganopolysiloxane, a diorgano hydrogen siloxy-terminated polyorganosiloxane, and a catalyst.

First organopolysiloxane

Since the first organopolysiloxane does not contain an alkenyl group, it does not affect the addition curing reaction and serves to impart adhesiveness to the composition.

At this time, the first organopolysiloxane is an R ¹ ₃ SiO _1/2 unit (in the formula, R ¹ is a substituted or unsubstituted C _1-10 alkyl group, or a hydroxyl group, and R ¹ may be the same or different, respectively.) And SiO ₂ units. Specifically, the first organopolysiloxane may be represented by Formula 1 below.

[Formula 1]

(R ¹ ₃ SiO _1/2 ) _a (SiO ₂ ) _b

In Formula 1, a+b is 1, and a/b is 0.1 to 2.0. Specifically, a+b may be 1, and a/b may be 0.6 to 1.7, or 0.6 to 1.0. When a/b is less than 0.6, the adhesive strength of the cured product of the silicone pressure-sensitive adhesive composition is low, and when it exceeds 1.7, the strength and hardness of the cured product are low.

Further, a may be 0.091 to 0.667, b may be 0.333 to 0.909, and specifically, a may be 0.375 to 0.630, and b may be 0.370 to 0.625.

R ¹ is a substituted or unsubstituted C _1-8 alkyl group or a hydroxyl group, and the alkyl group may be substituted with a hydroxyl group. At this time, the alkyl group may be, for example, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a cyclopentyl group, a cyclohexyl group, and the like, and specifically, a methyl group, an ethyl group, or a propyl group. Further, the substitution may be one substituted with one or more functional groups selected from the group consisting of a hydroxyl group, a halogen group, an alkoxy group and a cyano group.

Further, the first organopolysiloxane may be a trimethylsiloxy group-terminated silicate resin, and specifically, may be represented by Formula 6 below. In this case, a and b in Chemical Formula 6 are as defined in Chemical Formula 1.

[Formula 6]

(Me ₃ SiO _1/2 ) _a (SiO ₂ ) _b

More specifically, the first organopolysiloxane is (Me ₃ SiO _1/2 ) _0.5 (SiO ₂ ) _0.5 , (Me ₃ SiO _1/2 ) _0.4 (SiO ₂ ) _0.6 , (Me ₃ SiO _1/2 ) _0.45 (SiO ₂ ) _0.55 , (Me ₃ SiO _1/2 ) _0.6 (SiO ₂ ) It may be expressed as _0.4 . In this case, "Me" is a methyl group.

In addition, when R ¹ of the ^first organopolysiloxane is a hydroxyl group or contains an alkyl group substituted with a hydroxyl group, the first organopolysiloxane has a hydroxyl content of less than 5% by weight, 4% by weight based on the total weight of the first organopolysiloxane. % Or less, or 0.1 to 4% by weight.

In addition, the first organopolysiloxane may have a number average molecular weight (Mn) of 500 to 10,000 g/mol. Specifically, the first organopolysiloxane may have a number average molecular weight of 1,000 to 8,000 g/mol. If the number average molecular weight of the first organopolysiloxane is less than 500 g/mol, the adhesive strength and initial tack of the cured product is insufficient, and if it exceeds 10,000 g/mol, the compatibility of the first organopolysiloxane in the composition of the present invention is It decreases, and the strength of the cured product is insufficient, so that the cured product easily migrates to the adherend during peeling.

Further, the first organopolysiloxane may be included in the composition in an amount of 25 to 75 parts by weight based on 4 to 16 parts by weight of the second organopolysiloxane. Specifically, the first organopolysiloxane may be included in the composition in an amount of 30 to 70 parts by weight based on 4 to 16 parts by weight of the second organopolysiloxane. If the first organopolysiloxane is less than 25 parts by weight, the adhesive strength and initial adhesive strength of the cured product are insufficient, and when it is included in an amount exceeding 75 parts by weight, the viscosity of the composition increases, and the adhesive strength to the cured product is insufficient, so that it becomes an adherend upon peeling. The cured product becomes easy to migrate.

Second organopolysiloxane

The second organopolysiloxane is a crosslinking component including an alkenyl group, and forms a high-viscosity siloxane through a crosslinking reaction through an addition reaction with a diorgano hydrogen siloxy-terminated polyorganosiloxane and a role of imparting adhesiveness to the composition. .

At this time, the second organopolysiloxane is R ² R ³ ₂ SiO _1/2 unit (in the formula, R ² is a substituted or unsubstituted C _2-10 alkenyl group, and R ³ is a substituted or unsubstituted C _1-10 It is an alkyl group.), R ⁴ ₃ SiO _1/2 unit (wherein R ⁴ is a substituted or unsubstituted C _1-10 alkyl group.), and SiO ₂ units. Specifically, the second organopolysiloxane may be represented by Formula 2 below.

[Formula 2]

(R ² R ³ ₂ SiO _1/2 ) _c (R ⁴ ₃ SiO _1/2 ) _d (SiO ₂ ) _e

In Formula 2, c is 0.03 to 0.25, d is 0.1 to 0.5, and e is 0.35 to 0.65. Specifically, c may be 0.1 to 0.2, d may be 0.25 to 0.45, and e may be 0.4 to 0.6.

When c is less than 0.03, the reactivity of the second organopolysiloxane decreases, and when it exceeds 0.25, the crosslinking density of the cured product increases, and cracks may occur due to a change in crosslinking density over time.

When d is less than 0.1, the viscosity of the composition increases and flowability decreases, so workability may not be easy, and when d exceeds 0.5, the crosslinking density of the cured product may be lowered, resulting in a decrease in adhesion to the adherend.

When e is less than 0.35, the adhesive strength of the cured product of the composition decreases, and when it exceeds 0.65, the strength and hardness of the cured product may decrease.

Specifically, R ² is a substituted or unsubstituted C _2-8 alkenyl group, or a substituted or unsubstituted C _2-6 alkenyl group, and R ³ is a substituted or unsubstituted C _1-8 alkyl group, or a substituted or It is an unsubstituted C _1-6 alkyl group, and R ⁴ may be a substituted or unsubstituted C _1-8 alkyl group, or a substituted or unsubstituted C _1-6 alkyl group. In addition, the substitution may be one substituted with one or more functional groups selected from the group consisting of a hydroxyl group, a halogen group, an alkoxy group and a cyano group.

For example, R ² , R ³ and R ⁴ may be substituted with a hydroxyl group, and in this case, the hydroxyl group content may be 5% by weight or less, or 4% by weight or less based on the total weight of the second organopolysiloxane.

At this time, the alkyl group may be, for example, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a cyclopentyl group, a cyclohexyl group, and the like, and specifically, a methyl group, an ethyl group, or a propyl group. The alkenyl group may be, for example, a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, and the like, and specifically, a vinyl group or an allyl group.

Specifically, the second organopolysiloxane may be a resin including a vinyldimethylsiloxy group silicate and a trimethylsiloxy group terminal silicate, and may be, for example, represented by Formula 7 below. In this case, c, d, and e in Chemical Formula 7 are as defined in Chemical Formula 2.

[Formula 7]

(ViMe ₂ SiO _1/2 ) _c (Me ₃ SiO _1/2 ) _d (SiO ₂ ) _e

More specifically, the second organopolysiloxane is (ViMe ₂ SiO _1/2 ) _0.15 (Me ₃ SiO _1/2 ) _0.35 (SiO ₂ ) _0.5, (ViMe ₂ SiO _1/2 ) _0.10 (Me ₃ SiO _{1/ 2} ) _0.40 (SiO ₂ ) _0.5, (ViMe ₂ SiO _1/2 ) _0.2 (Me ₃ SiO _1/2 ) _0.3 (SiO ₂ ) _0.5, (ViMe ₂ SiO _1/2 ) _0.15 (Me ₃ SiO _1/2 ) _0.45 (SiO ₂ ) _0.4, (ViMe ₂ SiO _1/2 ) _0.10 (Me ₃ SiO _1/2 ) _0.50 (SiO ₂ ) _0.4, (ViMe ₂ SiO _1/2 ) _0.2 (Me ₃ SiO _1/2 ) _0.4 ( SiO ₂ ) _0.4, (ViMe ₂ SiO _1/2 ) _0.15 (Me ₃ SiO _1/2 ) _0.35 (SiO ₂ ) _0.6, (ViMe ₂ SiO _1/2 ) _0.15 (Me ₃ SiO _1/2 ) _0.25 (SiO ₂ ) _0.6, (ViMe ₂ SiO _1/2 ) _0.2 (Me ₃ SiO _1/2 ) _0.2 (SiO ₂ ) _0.6, etc. At this time, Vi is a vinyl group and Me is a methyl group.

In addition, the second organopolysiloxane may have a number average molecular weight (Mn) of 500 to 10,000 g/mol. Specifically, the second organopolysiloxane may have a number average molecular weight of 1,000 to 8,000 g/mol. If the number average molecular weight of the second organopolysiloxane is less than 500 g/mol, the adhesive strength and initial adhesion of the cured product are insufficient, and if it exceeds 10,000 g/mol, the compatibility of the second organopolysiloxane in the composition of the present invention and diorgano hydrogen The reactivity with the siloxy-terminated polyorganosiloxane is lowered, and the cured product has insufficient strength against adhesive force, so that the cured product easily migrates to the adherend during peeling.

Furthermore, the second organopolysiloxane may include a vinyl group, and in this case, the second organopolysiloxane may have a vinyl group content of 0.40 to 3.34 mmol/g, or 0.40 to 3.10 mmol/g. When the vinyl group content is less than 0.40 mmol/g, the reactivity of the second organopolysiloxane decreases, and when it exceeds 3.34 mmol/g, the crosslinking density of the cured product increases, and cracking may occur due to a change in crosslinking density over time.

In addition, the second organopolysiloxane may be included in the composition in an amount of 4 to 16 parts by weight based on 25 to 75 parts by weight of the first organopolysiloxane. Specifically, the second organopolysiloxane may be included in the composition in an amount of 5 to 15 parts by weight based on 25 to 75 parts by weight of the first organopolysiloxane. If the second organopolysiloxane is less than 4 parts by weight, the cured product has a low crosslinking density, so the strength is low, and if it exceeds 16 parts by weight, the cured product has a high crosslinking density, and cracking may occur due to a change in hardness over time.

Further, the composition comprises 30 to 80 parts by weight, or 35 to 75 parts by weight of the total amount of the first organopolysiloxane and the second organopolysiloxane (hereinafter referred to as ``total amount of organopolysiloxane'') based on 100 parts by weight of the first polysiloxane mixture. It may be included in an amount by weight. At this time, the first polysiloxane mixture refers to a mixture consisting of a first organopolysiloxane, a second organopolysiloxane, a first diorganopolysiloxane, a second diorganopolysiloxane, and a diorgano hydrogen siloxane-terminated polyorganosiloxane.

If the total of the first organopolysiloxane and the second organopolysiloxane is less than 30 parts by weight, the adhesive strength and initial adhesive strength of the cured product will be insufficient, and if it exceeds 75 parts by weight, the viscosity of the composition will increase. The transition of the cured product to the adherend becomes easy.

First diorganopolysiloxane

The first diorganopolysiloxane serves to adjust the viscosity of the composition and to form an elastomer component of the prepared cured product.

The first diorganopolysiloxane has at least two alkenyl groups in one molecule. Specifically, the first diorganopolysiloxane may be represented by Formula 3 below.

[Formula 3]

(R ⁵ R ⁶ ₂ SiO _1/2 ) ₂ (R ⁷ R ⁸ SiO) _f (R ⁹ ₂ SiO) _g

In Formula 3, R ⁵ may be a substituted or unsubstituted C _2-10 alkenyl, and specifically, may be a substituted or unsubstituted C _2-8 alkenyl, or an unsubstituted C _2-6 alkenyl.

R ⁶ may be a substituted or unsubstituted C _1-10 alkyl, specifically, a substituted or unsubstituted C _1-8 alkyl, or an unsubstituted C _1-6 alkyl.

The R ⁷ is a substituted or unsubstituted C _1-10 alkyl or a substituted or unsubstituted C _2-10 alkenyl, specifically, a substituted or unsubstituted C _1-8 alkyl, or an unsubstituted C _1-6 It can be alkyl.

The R ⁸ and R ⁹ are each independently substituted or unsubstituted C _1-6 alkyl or substituted or unsubstituted C _6-10 aryl, specifically, substituted or unsubstituted C _1-6 alkyl, or unsubstituted C _1-6 alkyl.

In this case, the substitution may be one substituted with one or more functional groups selected from the group consisting of a hydroxyl group, a halogen group, an alkoxy group, and a cyano group.

In addition, the alkyl group may be, for example, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a cyclopentyl group, a cyclohexyl group, and the like, and specifically, a methyl group, an ethyl group, or a propyl group. Further, the alkenyl group may be, for example, a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, and the like, and specifically, may be a vinyl group or an allyl group. In addition, the aryl group may be, for example, a phenyl group, a naphthyl group, biphenyl, anthracenyl, and the like, and specifically, may be a phenyl group or a naphthyl group.

F and g are each independently an integer of 0 or 1 or more, and f/(f+g) is 0 to 0.1. Specifically, f and g are each independently an integer of 0 to 2,200, and f/(f+g) may be 0 to 0.05.

Specifically, the first diorganopolysiloxane is a vinyldimethylsiloxy group-terminated dimethylsiloxane polymer, a vinyldimethylsiloxy group-terminated methylvinylsiloxane-dimethylsiloxane block copolymer, a trimethylsiloxy group-terminated methylvinylsiloxane-dimethylsiloxane block copolymer, and vinyldimethyl A siloxy group-terminated methylphenylsiloxane-dimethylsiloxane block copolymer, or a vinyldimethylsiloxy group-terminated diphenylsiloxane-dimethylsiloxane block copolymer.

More specifically, the first diorganopolysiloxane may include at least one selected from the group consisting of a vinyldimethylsiloxy group-terminated dimethylsiloxane polymer and a vinyldimethylsiloxy group-terminated methylvinylsiloxane-dimethylsiloxane block copolymer.

In this case, the vinyldimethylsiloxy group-terminated dimethylsiloxane polymer may be represented by Formula 8 below. In the following Chemical Formula 8, g is as defined in Chemical Formula 3.

[Formula 8]

(ViMe ₂ SiO _1/2 ) ₂ (Me ₂ SiO) _g

Specifically, the vinyldimethylsiloxy group terminal dimethylsiloxane polymer is (ViMe ₂ SiO _1/2 ) (Me ₂ SiO) ₆₅ (ViMe ₂ SiO _1/2 ), (ViMe ₂ SiO _1/2 ) (Me ₂ SiO) ₁₂₀ (ViMe ₂ SiO _1/2 ), (ViMe ₂ SiO _1/2 )(Me ₂ SiO) ₁₅₀ (ViMe ₂ SiO _1/2 ), (ViMe ₂ SiO _1/2 )(Me ₂ SiO) ₂₂₅ (ViMe ₂ SiO _1/2 ), (ViMe ₂ SiO _1/2 )(Me ₂ SiO) ₅₀₀ (ViMe ₂ SiO _1/2 ), (ViMe ₂ SiO _1/2 )(Me ₂ SiO) ₁₀₀₀ (ViMe ₂ SiO _1/2 ) , (ViMe ₂ SiO _1/2 ) (Me ₂ SiO) ₁₅₀₀ (ViMe ₂ SiO _1/2 ), and the like.

In addition, the vinyldimethylsiloxy group-terminated methylvinylsiloxane-dimethylsiloxane block copolymer may be represented by Formula 9 below. In the following Chemical Formula 9, f and g are as defined in Chemical Formula 3.

[Formula 9]

(ViMe ₂ SiO _1/2 ) ₂ (ViMeSiO) _f (Me ₂ SiO) _g

Specifically, the vinyldimethylsiloxy group terminal methylvinylsiloxane-dimethylsiloxane block copolymer is (ViMe ₂ SiO _1/2 ) (ViMeSiO) ₁ (Me ₂ SiO) ₆₄ (ViMe ₂ SiO _1/2 ), (ViMe ₂ SiO _1/2 )(ViMeSiO) ₂ (Me ₂ SiO) ₉₅ (ViMe ₂ SiO _1/2 ), (ViMe ₂ SiO _1/2 ) (ViMeSiO) ₃ (Me ₂ SiO) ₄₀₀ (ViMe ₂ SiO _1/2 ) , (ViMe ₂ SiO _1/2 ) (ViMeSiO) ₅ (Me ₂ SiO) ₁₀₀₀ (ViMe ₂ SiO _1/2 ).

In this case, Vi is a vinyl group and Me is a methyl group.

In addition, the first diorganopolysiloxane may have a viscosity of 100 to 1,000,000 mPa·s at 25°C. Specifically, the first diorganopolysiloxane may have a viscosity of 200 to 800,000 mPa·s, or 400 to 500,000 mPa·s at 25°C. If the viscosity of the first diorganopolysiloxane at 25°C is less than 100 mPa·s, the reliability of the cured product is deteriorated due to voids caused by volatile components during curing of the composition, and the viscosity of the first diorganopolysiloxane at 25°C is 1,000,000 mPa·s. When s is exceeded, workability may be deteriorated due to a decrease in flowability of the composition.

Further, the first diorganopolysiloxane may include a vinyl group, and in this case, the first diorganopolysiloxane may have a vinyl group content of 0.015 to 0.6 mmol/g, or 0.018 to 0.5 mmol/g. When the vinyl group content of the first diorganopolysiloxane is less than 0.015 mmol/g, the workability decreases due to the decrease in flowability of the composition, and when the vinyl group content of the first diorganopolysiloxane exceeds 0.6 mmol/g, the composition is cured. The reliability of the cured product may deteriorate due to voids caused by heavy volatile components.

In addition, the first diorganopolysiloxane may be included in the composition in an amount of 5 to 65 parts by weight based on 25 to 75 parts by weight of the first organopolysiloxane. Specifically, the first diorganopolysiloxane may be included in the composition in an amount of 10 to 60 parts by weight based on 25 to 75 parts by weight of the first organopolysiloxane. If the first diorganopolysiloxane is less than 5 parts by weight, the viscosity of the composition cannot be sufficiently lowered, the hardness and strength of the cured product are insufficient, and if it exceeds 65 parts by weight, the adhesive strength and initial adhesive strength of the cured product are insufficient.

Second diorganopolysiloxane

The second diorganopolysiloxane serves to control the viscosity of the composition and to form an elastomer component of the prepared cured product. That is, the second diorganopolysiloxane serves to participate in the addition curing reaction including an alkenyl group, and serves to appropriately control the viscosity of the composition with high viscosity.

The second diorganopolysiloxane has at least two alkenyl groups in one molecule. Specifically, the second diorganopolysiloxane may be represented by Formula 4 below.

[Formula 4]

(R ¹⁰ R ¹¹ ₂ SiO _1/2 ) ₂ (R ¹² R ¹³ SiO) _h (R ¹⁴ ₂ SiO) _i

In Chemical Formula 4, R ¹⁰ may be a substituted or unsubstituted C _2-10 alkenyl, and specifically, may be a substituted or unsubstituted C _2-8 alkenyl, or an unsubstituted C _2-6 alkenyl.

R ¹¹ may be a substituted or unsubstituted C _1-10 alkyl, and specifically, may be a substituted or unsubstituted C _1-8 alkyl, or an unsubstituted C _1-6 alkyl.

The R ¹² is a substituted or unsubstituted C _1-10 alkyl or a substituted or unsubstituted C _2-10 alkenyl, specifically, a substituted or unsubstituted C _1-8 alkyl, or an unsubstituted C _1-6 It can be alkyl.

The R ¹³ and R ¹⁴ are each independently substituted or unsubstituted C _1-6 alkyl or substituted or unsubstituted C _6-10 aryl, specifically, substituted or unsubstituted C _1-6 alkyl, or unsubstituted C _1-6 alkyl.

In this case, the substitution may be one substituted with one or more functional groups selected from the group consisting of a hydroxyl group, a halogen group, an alkoxy group, and a cyano group.

In addition, the alkyl group may be, for example, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a cyclopentyl group, a cyclohexyl group, and the like, and specifically, a methyl group, an ethyl group, or a propyl group. Further, the alkenyl group may be, for example, a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, and the like, and specifically, may be a vinyl group or an allyl group. In addition, the aryl group may be, for example, a phenyl group, a naphthyl group, biphenyl, anthracenyl, and the like, and specifically, may be a phenyl group or a naphthyl group.

The h and i are each independently an integer of 0 or 1 or more, and h/(h+i) is 0 to 0.1. Specifically, h and i are each independently an integer of 0 to 12,000, h/(h+i) may be 0 to 0.05.

Specifically, the second diorganopolysiloxane is a vinyldimethylsiloxy group-terminated dimethylsiloxane polymer, a vinyldimethylsiloxy group-terminated methylvinylsiloxane-dimethylsiloxane block copolymer, a trimethylsiloxy group-terminated methylvinylsiloxane-dimethylsiloxane block copolymer, and vinyldimethyl A siloxy group-terminated methylphenylsiloxane-dimethylsiloxane block copolymer or a vinyldimethylsiloxy group-terminated diphenylsiloxane-dimethylsiloxane block copolymer. More specifically, the second diorganopolysiloxane may be at least one selected from the group consisting of a vinyldimethylsiloxy group-terminated dimethylsiloxane polymer and a vinyldimethylsiloxy group-terminated methylvinylsiloxane-dimethylsiloxane block copolymer.

In this case, the vinyldimethylsiloxy group-terminated dimethylsiloxane polymer may be represented by Formula 10 below. In this case, i in Chemical Formula 10 is as defined in Chemical Formula 4.

[Formula 10]

(ViMe ₂ SiO _1/2 ) ₂ (Me ₂ SiO) _i

Specifically, the vinyldimethylsiloxy group terminal dimethylsiloxane polymer is (ViMe ₂ SiO _1/2 ) (Me ₂ SiO) ₂₅₀₀ (ViMe ₂ SiO _1/2 ), (ViMe ₂ SiO _1/2 ) (Me ₂ SiO) ₅₀₀₀ (ViMe ₂ SiO _1/2 ), (ViMe ₂ SiO _1/2 )(Me ₂ SiO) ₇₅₀₀ (ViMe ₂ SiO _1/2 ), (ViMe ₂ SiO _1/2 )(Me ₂ SiO) ₁₀₀₀₀ (ViMe ₂ SiO _1/2 ) can be displayed.

In addition, the vinyldimethylsiloxy group-terminated methylvinylsiloxane-dimethylsiloxane block copolymer may be represented by Formula 11 below. In this case, h and i in Chemical Formula 11 are as defined in Chemical Formula 4.

[Formula 11]

(ViMe ₂ SiO _1/2 ) ₂ (ViMeSiO) _h (Me ₂ SiO) _i

Specifically, the vinyldimethylsiloxy group terminal methylvinylsiloxane-dimethylsiloxane block copolymer is (ViMe ₂ SiO _1/2 ) (ViMeSiO) ₅ (Me ₂ SiO) ₇₀₀₀ (ViMe ₂ SiO _1/2 ), (ViMe ₂ SiO _1/2 ) (ViMeSiO) ₃₅ (Me ₂ SiO) ₇₀₀₀ (ViMe ₂ SiO _1/2 ), (ViMe ₂ SiO _1/2 ) (ViMeSiO) ₂₀ (Me ₂ SiO) ₇₅₀₀ (ViMe ₂ SiO _1/2 ), (ViMe ₂ SiO _1/2 ) (ViMeSiO) ₅ (Me ₂ SiO) ₁₀₀₀₀ (ViMe ₂ SiO _1/2 ) and the like.

In addition, the first diorganopolysiloxane has a viscosity lower than that of the second diorganopolysiloxane at 25°C. Specifically, the second diorganopolysiloxane may have a viscosity of more than 1,000,000 mPa·s at 25°C. That is, the second diorganopolysiloxane may be in the form of a gum. When the viscosity of the second diorganopolysiloxane is within the above range at 25° C., the adhesive strength of the cured product may be improved by appropriately controlling the viscosity decrease of the composition due to the solvent. In addition, when the viscosity of the second diorganopolysiloxane at 25°C is 1,000,000 mPa·s or less, the viscosity of the composition is sufficient, the strength of the cured product is insufficient, and the gel is transferred to the adherend when peeling from the adherend (adhesive residual). It becomes easy to occur.

Further, the second diorganopolysiloxane may have a degree of polymerization of 2,300 to 12,000, or 2,500 to 11,000. In this case, the degree of polymerization is the number of silicon atoms in one molecule of the second diorganopolysiloxane.

In addition, the second diorganopolysiloxane may be included in the composition in an amount of 5 to 20 parts by weight based on 25 to 75 parts by weight of the first organopolysiloxane. Specifically, the second diorganopolysiloxane may be included in the composition in an amount of 7 to 18 parts by weight based on 25 to 75 parts by weight of the first organopolysiloxane. If the second diorganopolysiloxane is less than 5 parts by weight, the viscosity of the composition cannot be sufficiently increased, and if it exceeds 20 parts by weight, the viscosity of the composition may be excessively increased.

In addition, the composition includes 10 to 70 parts by weight, or 15 to 60 parts by weight of the total amount of the first diorganopolysiloxane and the second diorganopolysiloxane (hereinafter referred to as'the total amount of diorganopolysiloxane') based on 100 parts by weight of the first polysiloxane mixture. It may be included in an amount by weight. At this time, the first polysiloxane mixture refers to a mixture consisting of a first organopolysiloxane, a second organopolysiloxane, a first diorganopolysiloxane, a second diorganopolysiloxane, and a diorgano hydrogen siloxane-terminated polyorganosiloxane. When the total amount of diorganopolysiloxane is less than 10 parts by weight, the hardness and strength of the cured product are insufficient, and when it exceeds 70 parts by weight, the adhesive strength and initial adhesion of the cured product are insufficient.

Diorgano hydrogen siloxy-terminated polyorganosiloxane

The diorgano hydrogen siloxy-terminated polyorganosiloxane is crosslinked with the first diorganopolysiloxane through a chain extension reaction to form a high molecular weight siloxane, thereby forming an elastomer component of the cured product.

The diorgano hydrogen siloxy-terminated polyorganosiloxane includes at least one hydrogen group directly bonded to a silicon atom in one molecule, and specifically, may include at least two hydrogen groups directly bonded to a silicon atom in one molecule. . More specifically, the diorgano hydrogen siloxy-terminated polyorganosiloxane may be represented by Formula 5 below.

[Formula 5]

(HR ¹⁵ ₂ SiO _1/2 ) ₂ (HR ¹⁶ SiO) _j (R ¹⁷ ₂ SiO) _k

In Formula 5, R ¹⁵ , R ¹⁶ and R ¹⁷ are each independently C _1-6 alkyl or C _6-10 aryl, specifically, substituted or unsubstituted C _1-6 alkyl, or unsubstituted C _{1 It} may be _-6 alkyl.

J and k are each independently an integer of 0 or 1 or more, j/(j+k) is 0 to 0.1, specifically, j and k are each independently an integer of 0 to 500, j/(j +k) may be 0 to 0.05.

In addition, the alkyl group may be, for example, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a cyclopentyl group, a cyclohexyl group, and the like, and specifically, a methyl group, an ethyl group, or a propyl group. Further, the aryl group may be, for example, a phenyl group, a naphthyl group, a biphenyl, anthracenyl, and the like, and specifically, a phenyl group or a naphthyl group.

Specifically, the diorgano hydrogen siloxy-terminated polyorganosiloxane is a dimethyl hydrogen siloxy-terminated dimethylsiloxane polymer, a dimethyl hydrogen siloxy-terminated methyl hydrogen siloxane-dimethylsiloxane block copolymer, a dimethyl hydrogen siloxy-terminated methyl hydrogen siloxane-methylphenyl Siloxane block copolymer, dimethyl hydrogen siloxy-terminated methyl hydrogen siloxane-methylphenylsiloxane block copolymer, dimethyl hydrogen siloxy-terminated methyl hydrogen siloxane-diphenylsiloxane block copolymer, diphenyl hydrogen siloxy-terminated dimethylsiloxane polymer, and the like. . More specifically, the diorgano hydrogen siloxy-terminated polyorganosiloxane may be at least one selected from the group consisting of a dimethyl hydrogen siloxy-terminated dimethylsiloxane polymer and a dimethyl hydrogen siloxy-terminated methyl hydrogen siloxane-dimethylsiloxane block copolymer. .

In this case, the dimethyl hydrogen siloxy-terminated dimethylsiloxane polymer may be represented by Formula 12 below. In this case, k in Chemical Formula 12 is as defined in Chemical Formula 5.

[Formula 12]

(HMe ₂ SiO _1/2 ) ₂ (Me ₂ SiO) _k

Specifically, the dimethyl hydrogen siloxy-terminated dimethylsiloxane polymer is (HMe ₂ SiO _1/2 ) (Me ₂ SiO) ₂₀ (HMe ₂ SiO _1/2 ), (HMe ₂ SiO _1/2 ) (Me ₂ SiO) ₄₅ (HMe ₂ SiO _1/2 ), (HMe ₂ SiO _1/2 )(Me ₂ SiO) ₂₂₀ (HMe ₂ SiO _1/2 ), (HMe ₂ SiO _1/2 )(Me ₂ SiO) ₃₅₀ (HMe ₂ SiO _1/2 ) can be displayed.

In addition, the dimethyl hydrogen siloxy-terminated methyl hydrogen siloxane-dimethylsiloxane block copolymer may be represented by Formula 13 below. In this case, j and k in Chemical Formula 13 are as defined in Chemical Formula 5.

[Formula 13]

(HMe ₂ SiO _1/2 ) ₂ (HMeSiO) _j (Me ₂ SiO) _k

Specifically, the dimethyl hydrogen siloxy-terminated methyl hydrogen siloxane-dimethylsiloxane block copolymer is (HMe ₂ SiO _1/2 ) (HMeSiO) ₁ (Me ₂ SiO) ₁₉ (HMe ₂ SiO _1/2 ), (HMe ₂ SiO _1/2 )(HMeSiO) ₃ (Me ₂ SiO) ₄₂ (HMe ₂ SiO _1/2 ), (HMe ₂ SiO _1/2 ) (HMeSiO) ₁₀ (Me ₂ SiO) ₂₁₀ (HMe ₂ SiO _1/2 ), (HMe ₂ SiO _1/2 ) (HMeSiO) ₁₀ (Me ₂ SiO) ₃₅₀ (HMe ₂ SiO _1/2 ) and the like.

In this case, "Me" is a methyl group.

Further, the diorgano hydrogen siloxy-terminated polyorganosiloxane may have a viscosity of 10 to 3,000 mPa·s, or 20 to 1,000 mPa·s at 25°C. If the viscosity of the diorgano hydrogen siloxy-terminated polyorganosiloxane at 25°C is less than 10 mPa·s, the high molecular weight of the siloxane by the chain extension reaction is insufficient, and the strength of the cured product decreases, and the diorgano hydrogen siloxy-terminated polyorganosiloxane If the viscosity of the organosiloxane at 25° C. exceeds 3,000 mPa·s, the amount of SiH content is low, so the amount of the organosiloxane needs to be increased, and thus workability may be deteriorated due to a decrease in flowability of the composition.

In addition, the diorgano hydrogen siloxy-terminated polyorganosiloxane may have a content of a hydrogen group (-SiH) directly bonded to a silicon atom of 0.05 to 2.3 mmol/g, or 0.12 to 1.2 mmol/g. If the hydrogen group (-SiH) content of the diorgano hydrogen siloxy-terminated polyorganosiloxane is less than 0.05 mmol/g, the amount of SiH content is low, so the amount of use must be increased. If it is lowered and exceeds 2.3 mmol/g, the strength of the cured product may decrease due to insufficient high molecular weight of the siloxane due to the chain extension reaction.

In addition, the composition may include a hydrogen group directly bonded to a silicon atom of a diorgano hydrogen siloxy-terminated polyorganosiloxane and an alkenyl group of the second polysiloxane mixture in a molar ratio of 0.5 to 2:1. In this case, the second polysiloxane mixture refers to a mixture consisting of a second organopolysiloxane, a first diorganopolysiloxane, and a second diorganopolysiloxane. When the ratio of the number of moles of SiH groups to the number of moles of alkenyl groups in the second polysiloxane mixture is less than 0.5, the crosslinking density of the cured product is low and the strength is low. This may happen.

Further, the diorgano hydrogen siloxy-terminated polyorganosiloxane may be included in the composition in an amount of 1 to 10 parts by weight based on 25 to 75 parts by weight of the first organopolysiloxane.

Triorganosiloxy-terminated polyorgano hydrogen siloxane

In addition, the silicone pressure-sensitive adhesive composition of the present invention may further include a triorganosiloxy-terminated polyorgano hydrogen siloxane. At this time, the triorganosiloxy-terminated polyorgano hydrogen siloxane serves to increase the degree of crosslinking of the composition and increase the hardness.

The triorganosiloxy-terminated polyorgano hydrogen siloxane may be represented by Formula 14 below.

[Formula 14]

(R ¹⁸ ₃ SiO _1/2 ) ₂ (HR ¹⁹ SiO) _l (R ²⁰ ₂ SiO) _m

In Formula 14, R ¹⁸ , R ¹⁹ and R ²⁰ are each independently C _1-6 alkyl or C _6-10 aryl, specifically, substituted or unsubstituted C _1-6 alkyl, or unsubstituted C _{1- 6} may be alkyl.

l is an integer of 2 or more, m is an integer of 0 or 1 or more, and l/(l+m) is 0.005 to 1. Specifically, l is an integer of 3 to 500, m is an integer of 3 to 500, and l/(l+m) may be 0.1 to 0.6.

For example, the triorganosiloxy-terminated polyorgano hydrogen siloxane may include a trimethylsiloxy group-terminated methyl hydrogen siloxane polymer or a trimethylsiloxy group-terminated methyl hydrogen siloxane-dimethylsiloxane block copolymer.

Specifically, the trimethylsiloxy group-terminated methyl hydrogen siloxane polymer may be represented by Formula 15 below. In this case, in Chemical Formula 15, l is as defined in Chemical Formula 14.

[Formula 15]

(Me ₃ SiO _1/2 ) ₂ (HMeSiO) _l

More specifically, the trimethylsiloxy group terminal methyl hydrogen siloxane polymer is (Me ₃ SiO _1/2 ) (HMeSiO) ₂₀ (Me ₃ SiO _1/2 ), (Me ₃ SiO _1/2 ) (HMeSiO) ₄₀ (Me ₃ SiO _1/2 ) and the like.

In addition, the trimethylsiloxy group terminal methyl hydrogen siloxane-dimethylsiloxane block copolymer may be specifically represented by Formula 16. In this case, l and m in Chemical Formula 16 are as defined in Chemical Formula 14.

[Formula 16]

(Me ₃ SiO _1/2 ) ₂ (HMeSiO) _l (Me ₂ SiO) _m

More specifically, the trimethylsiloxy group terminal methyl hydrogen siloxane-dimethylsiloxane block copolymer, (Me ₃ SiO _1/2 ) (HMeSiO) ₂₀ (Me ₂ SiO) ₂₀ (Me ₃ SiO _1/2 ), (Me ₃ SiO _1/2 )(HMeSiO) ₁₂ (Me ₂ SiO) ₂₅ (Me ₃ SiO _1/2 ), (Me ₃ SiO _1/2 )(HMeSiO) ₂₀ (Me ₂ SiO) ₄₆ (Me ₃ SiO _1/2 ), (Me ₃ SiO _1/2 )(HMeSiO) ₁₀ (Me ₂ SiO) ₁₀₀ (Me ₃ SiO _1/2 ), (Me ₃ SiO _1/2 )(HMeSiO) ₃ (Me ₂ SiO) ₇ (Me ₃ SiO _1/2 ) and the like.

In this case, "Me" is a methyl group.

In addition, the triorganosiloxy-terminated polyorgano hydrogen siloxane may have a viscosity of 10 to 3,000 mPa·s, or 20 to 1,000 mPa·s at 25°C. If the viscosity of the triorganosiloxy-terminated polyorgano hydrogen siloxane at 25°C is less than 10 mPa·s, the high molecular weight of the siloxane by the crosslinking reaction is insufficient, and the strength of the cured product decreases, and if it exceeds 3,000 mPa·s , As the flowability of the composition decreases, workability may decrease.

Further, the triorganosiloxy-terminated polyorgano hydrogen siloxane may have a content of a hydrogen group (-SiH) directly bonded to a silicon atom from 0.05 to 16 mmol/g, or from 0.1 to 10 mmol/g. If the hydrogen group (-SiH) content of the triorganosiloxy-terminated polyorgano hydrogen siloxane is less than 0.05 mmol/g, the amount of -SiH content is low, so it is necessary to increase the amount, and as a result, the flowability of the composition decreases. As a result, workability is lowered, and when it exceeds 16 mmol/g, the crosslinking point may be locally concentrated and the strength of the cured product may decrease.

In addition, the composition may include a hydrogen group directly bonded to a silicon atom of a diorgano hydrogen siloxy-terminated polyorganosiloxane and an alkenyl group of the second polysiloxane mixture in a molar ratio of 0.5 to 2: 1. 90 mol% may be substituted with a hydrogen group directly bonded to the silicon atom of the triorganosiloxy-terminated polyorgano hydrogen siloxane. When the triorganosiloxy-terminated polyorgano hydrogen siloxane is substituted by more than 90 mol% by a hydrogen group directly bonded to a silicon atom, the crosslinking density of the cured product increases, and cracking may occur due to a change in hardness over time.

catalyst

The catalyst serves to promote an addition reaction between the components of the composition, that is, an addition reaction of an alkenyl group and a SiH group.

The catalyst may be generally used without particular limitation as long as it can be used as an addition reaction catalyst to the silicone pressure-sensitive adhesive composition, and may be, for example, a platinum catalyst. Specifically, the platinum catalyst is a platinum halide such as PtCl ₄ , H ₂ PtCl ₄ ·6H ₂ 0, Na ₂ PtCl ₄ ·4H ₂ 0, H ₂ PtCl ₄ ·6H ₂ 0 Reaction product containing cyclohexane), platinum-olefin complex, platinum-alcohol complex, platinum-alcolat complex, platinum-ether complex, platinum-aldehyde complex, platinum-ketone complex, platinum-vinylsiloxane complex (for example, Platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex), bis-(γ-picoline)-platinum dichloride, trimethylenedipyridine-platinum dichloride, dicyclopentadiene -Platinum dichloride, cyclooctadiene-platinum dichloride, cyclopentadiene-platinum dichloride), bis(alkynyl)bis(triphenylphosphine)platinum complex, bis(alkenyl)(cyclooctadiene)platinum complex, etc. Can be mentioned.

In addition, the catalyst may contain a platinum atom in an amount of 0.01 to 500 ppm, or 0.1 to 100 ppm, based on 100 parts by weight of the first polysiloxane mixture. At this time, the first polysiloxane mixture refers to a mixture consisting of a first organopolysiloxane, a second organopolysiloxane, a first diorganopolysiloxane, a second diorganopolysiloxane, and a diorgano hydrogen siloxane-terminated polyorganosiloxane. When the content of the platinum atom is less than 0.01 ppm, curing of the silicone pressure-sensitive adhesive composition is significantly delayed or crosslinking is insufficient, resulting in insufficient hardness and strength of the cured product. In addition, when the content of platinum atoms exceeds 500 ppm, the storage stability of the composition decreases, and when a retarder is added to improve this, the curability of the composition deteriorates, and the appearance of the cured product becomes yellowish coloration, which becomes unsuitable for optical use.

solvent

The silicone pressure-sensitive adhesive composition may further include a solvent. At this time, the solvent serves to dissolve the polysiloxane and adjust the viscosity of the composition.

The solvent does not inhibit the addition reaction in the composition and is not particularly limited as long as it is usually included in the silicone pressure-sensitive adhesive composition.

For example, the solvent may be an organic solvent including a hydrocarbon-based, an ester-based, a ketone-based, and a mixture thereof. In addition, the hydrocarbon system includes, for example, toluene, xylene, heptane and the like. Further, the ester system includes, for example, methyl acetate, ethyl acetate, isopropyl acetate, n-butyl acetate, and the like, and the ketone system is, for example, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone Etc.

In addition, the organic solvent may be included in an amount of 0 to 400 parts by weight, or 0 to 100 parts by weight based on 100 parts by weight of the first polysiloxane mixture. At this time, the first polysiloxane mixture refers to a mixture consisting of a first organopolysiloxane, a second organopolysiloxane, a first diorganopolysiloxane, a second diorganopolysiloxane, and a diorgano hydrogen siloxane-terminated polyorganosiloxane. When the content of the solvent exceeds 400 parts by weight, evaporation of the solvent during heat curing of the silicone pressure-sensitive adhesive composition takes time, resulting in a prolonged process time, and it is difficult to uniformly obtain a cured product of 100 μm or more.

Further, the solvent may be a reactive organic solvent obtained by addition reaction of a solvent containing an alkenyl group having an alkenyl group with a SiH group of a diorgano hydrogen siloxy-terminated polyorganosiloxane. At this time, the reactive organic solvent dissolves the silicone component as described above, and any reactive organic solvent that reacts with the diorgano hydrogen siloxy-terminated polyorganosiloxane may be used without particular limitation. For example, the alkenyl group-containing solvent may include hexene, octane, decene, dodecene, tetradecene, hexadecene and octadecene.

The reactive organic solvent may contain 0 to 10 parts by weight based on 100 parts by weight of the first polysiloxane mixture. When the reactive organic solvent exceeds 10 parts by weight, upon heating and curing of the silicone pressure-sensitive adhesive composition, the addition reaction time is lengthened, so that the process time is lengthened, and the content of the siloxane mixture decreases, so that the adhesion may decrease. At this time, the first polysiloxane mixture refers to a mixture consisting of a first organopolysiloxane, a second organopolysiloxane, a first diorganopolysiloxane, a second diorganopolysiloxane, and a diorgano hydrogen siloxane-terminated polyorganosiloxane.

additive

The silicone pressure-sensitive adhesive composition contains at least one additive selected from the group consisting of an addition reaction inhibitor, an adhesion promoter, a filler, a silicone rubber powder, a silicone resin powder, a heat resistance agent, an antioxidant, a radical scavenger, a light stabilizer, a flame retardant additive, and a diluent. It may contain additionally.

The silicone pressure-sensitive adhesive composition may have a viscosity of 500 to 20,000 mPa·s, or 1,000 to 10,000 mPa·s at 25°C.

In addition, the cured product having a thickness of 6mm prepared from the silicone pressure-sensitive adhesive composition may have a hardness of 1 to 100 shore OO, or 5 to 50 shore OO.

Further, the cured product having a thickness of 150 μm prepared from the silicone pressure-sensitive adhesive composition may have an adhesive strength of 1 to 50 N/25mm, or 2 to 28 N/25mm.

The silicone pressure-sensitive adhesive composition according to the present invention as described above uses a diorganopolysiloxane containing an alkenyl group and a diorgano hydrogen siloxy-terminated polyorganosiloxane to form a high molecular weight siloxane through a chain extension reaction during heat curing. The thick film can be manufactured with a uniform thickness. In addition, the silicone pressure-sensitive adhesive composition uses a high-viscosity diorganopolysiloxane to appropriately adjust the viscosity, so that the organic solvent content is small and the fluidity is good. Further, the cured product prepared from the silicone pressure-sensitive adhesive composition has less discoloration due to high temperature and/or high humidity environment, or UV irradiation, and maintains transparency or adhesive strength, and is excellent in long-term reliability. In addition, the cured product prepared from the silicone pressure-sensitive adhesive composition has adequate cohesiveness and strength, and can be removed without leaving a residue on the adherend when peeling from the adherend, and thus excellent reworkability. Due to the above-described effects, the silicone pressure-sensitive adhesive composition according to the present invention is very suitable as a pressure-sensitive adhesive for an image display device or a silicone pressure-sensitive adhesive for various fields.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the description by the following examples is only intended to specifically describe specific embodiments of the present invention, and is not intended to limit or limit the scope of the present invention to the contents described in these examples.

[Example]

Example 1. Preparation of silicone pressure-sensitive adhesive composition

45 parts by weight of the first organopolysiloxane, 9 parts by weight of the second organopolysiloxane, 23 parts by weight of the first diorganopolysiloxane-1, 9 parts by weight of the first diorganopolysiloxane-2, 9 parts by weight of the second diorganopolysiloxane-1 And 45 parts by weight of xylene were uniformly mixed. Then, 5 parts by weight of diorgano hydrogen siloxy-terminated polyorganosiloxane and 0.05 parts by weight of an addition reaction inhibitor were added and mixed uniformly, and 0.05 parts by weight of a platinum-vinylsiloxane complex solution having a platinum atom content of 1% by weight was added as a catalyst. And uniformly mixed to prepare a silicone pressure-sensitive adhesive composition.

Examples 2 to 12 and Comparative Examples 1 to 18.

A silicone pressure-sensitive adhesive composition was prepared in the same manner as in Example 1, except that the composition as described in Tables 1 to 3 was used. In this case, SiH/SiVi in Tables 1 to 3 is the number of moles of hydrogen directly bonded to the silicon atom relative to the number of moles of the vinyl group bonded to the silicon atom.

(Part by weight) Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 First organo polysiloxane 45.0 36.0 54.0 63.0 45.0 54.0 45.0 45.0 25.0 75.0 Second organo polysiloxane 9.0 9.0 9.0 9.0 9.0 9.0 5.0 15.0 5.0 5.0 First diorgano polysiloxane-1 23.0 33.6 12.4 1.7 - - 32.9 8.3 52.6 3.4 First diorgano polysiloxane-2 9.0 9.0 9.0 9.0 23.2 15.0 5.0 15.0 5.0 5.0 First diorgano polysiloxane-3 - - - - 10.0 10.0 - - - - Second diorgano polysiloxane-1 9.0 7.2 10.8 12.6 5.0 5.0 9.0 9.0 9.0 9.0 Diorgano hydrogen siloxy-terminated polyorgano siloxane 5.00 5.16 4.84 4.67 7.80 7.00 3.10 7.70 3.45 2.65 catalyst
(Platinum content) 5ppm 5ppm 5ppm 5ppm 5ppm 5 ppm 5 ppm 5 ppm 5 ppm 5 ppm Addition reaction inhibitor 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Xylene 45.0 45.0 45.0 45.0 - - 45.0 45.0 45.0 45.0 SiH/SiVi ratio 0.816 0.816 0.816 0.815 0.864 0.870 0.807 0.806 0.814 0.815 Solvent content (%) 31.0 31.0 31.0 31.0 0.0 0.0 31.0 31.0 31.0 31.0

(Part by weight) Example 11 Example 12 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 First organo polysiloxane 25.0 45.0 23.0 77.0 23.0 45.0 77.0 23.0 45.0 45.0 Second organo polysiloxane 15.0 9.0 9.0 5.0 3.0 3.0 3.0 17.0 17.0 9.0 First diorgano polysiloxane-1 28.0 12.1 44.7 1.9 58.9 37.3 6.3 42.6 17.9 34.9 First diorgano polysiloxane-2 15.0 9.0 9.0 4.5 3.5 3.5 3.0 3.5 3.5 3.5 Second diorgano polysiloxane-1 9.0 20.0 9.0 9.0 9.0 9.0 9.0 6.0 9.0 3.0 Diorgano hydrogen siloxy-terminated polyorgano siloxane 8.00 4.90 5.35 2.60 2.60 2.25 1.70 7.90 7.60 4.60 catalyst
(Platinum content) 5ppm 5ppm 5ppm 5ppm 5ppm 5ppm 5ppm 5ppm 5ppm 5ppm Addition reaction inhibitor 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Xylene 45.0 45.0 45.0 45.0 45.0 45.0 45.0 45.0 45.0 45.0 SiH/SiVi ratio 0.804 0.815 0.816 0.822 0.817 0.818 0.821 0.804 0.812 0.815 Solvent content (%) 31.0 31.0 31.0 31.0 31.0 31.0 31.0 31.0 31.0 31.0

(Part by weight) Comparative Example 9 Comparative Example 10 Comparative Example 11 Comparative Example 12 Comparative Example 13 Comparative Example 14 Comparative Example 15 Comparative Example 16 Comparative Example 17 Comparative Example 18 First organo polysiloxane 45.0 25.0 75.0 75.0 45.0 45.0 75.0 - 45.0 45.0 Second organo polysiloxane 9.0 5.0 15.0 15.0 - 9.0 15.0 9.0 - 9.0 First diorgano polysiloxane-1 14.5 58.2 1.6 0.2 41.4 22.9 - - - 29.4 First diorgano polysiloxane-2 5.0 3.5 3.5 1.5 3.5 9.0 - 79.5 50.1 11.4 Second diorgano polysiloxane-1 22.0 5.0 0.8 5.0 9.0 - - - - - Second diorgano polysiloxane-2 - - - - - 9.0 - - - - Diorgano hydrogen siloxy-terminated polyorgano siloxane 4.55 3.35 4.00 3.35 1.1 5.1 10.0 11.5 4.9 5.2 catalyst
(Platinum content) 5 ppm 5 ppm 5 ppm 5 ppm 5 ppm 5 ppm 5 ppm 5 ppm 5 ppm 5 ppm Addition reaction inhibitor 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Xylene 45.0 45.0 - - 45 45 45 - - 45 SiH/SiVi ratio 0.813 0.811 0.503 0.433 0.825 0.823 1.333 0.819 0.815 0.821 Solvent content (%) 31.0 31.0 0.0 0.0 31.0 31.0 31.0 0 0 31.0

Components and product names of each component used in the following Examples and Comparative Examples are shown in Table 4 below.

division ingredient First organo polysiloxane Trimethyl siloxy group-terminated silicate resin ((Me ₃ SiO _1/2 ) _0.5 (SiO ₂ ) _0.5 )
(SiO ₂ unit: 50 mol%, hydroxyl content: 1.2 wt%, Mn: 3,000 g/mol) Second organo polysiloxane Vinyldimethylsiloxy group/trimethylsiloxy group terminal silicate resin ((ViMe ₂ SiO _1/2 ) _0.038 (Me ₃ SiO _1/2 ) _0.462 (SiO ₂ ) _0.5 )
(SiO ₂ unit: 50 mol%, vinyl group content: 0.5 mmol/g, Mn: 3,000 g/mol) First diorgano polysiloxane-1 Polydimethylsiloxane ((ViMe ₂ SiO _1/2 )(Me ₂ SiO) ₁₂₀₀ (ViMe ₂ SiO _1/2 )) blocking both ends of dimethylvinylsiloxy group
(Vinyl group content: 0.02mmol/g, viscosity at 25°C: 150,000mPa·s) First diorgano polysiloxane-2 Polydimethylsiloxane ((ViMe ₂ SiO _1/2 )(Me ₂ SiO) ₂₂₅ (ViMe ₂ SiO _1/2 )) blocking both ends of dimethylvinylsiloxy group
(Vinyl group content: 0.12mmol/g, viscosity at 25°C: 1,000mPa·s) First diorgano polysiloxane-3 Polydimethylsiloxane ((ViMe ₂ SiO _1/2 )(Me ₂ SiO) ₁₅₀ (ViMe ₂ SiO _1/2 )) blocking both ends of dimethylvinylsiloxy group
(Vinyl group content: 0.17mmol/g, viscosity at 25°C: 400mPa·s) Second diorgano polysiloxane-1 Poly[dimethylsiloxane-methylvinylsiloxane]((ViMe ₂ SiO _1/2 ) ₂ (ViMeSiO) ₅ (Me ₂ SiO) _10,000 )
(Vinyl group content: 0.01mmol/g, degree of polymerization: 10,000, Gum state) Second diorgano polysiloxane-2 Poly[dimethylsiloxane-methylvinylsiloxane]((ViMe ₂ SiO _1/2 ) ₂ (ViMeSiO) _0.81 (Me ₂ SiO) ₂₁₀₀ )
(Vinyl group content: 0.018mmol/g, viscosity at 25℃: 900,000mPa·s, oil form) Diorgano hydrogen siloxy-terminated polyorganosiloxane Polydimethylsiloxane blocking hydrogen dimethylsiloxy group at both ends
((HMe ₂ SiO _1/2 )(Me ₂ SiO) ₂₄ (HMe ₂ SiO _1/2 ))
(Hydrogen content directly bonded to silicon: 1.0mmol/g, viscosity at 25°C: 20mPa·s) catalyst Platinum-vinylsiloxane complex solution 　 (platinum atom content: 1% by weight) Addition reaction inhibitor 2-methyl-3-butyne-2-ol

Test example. Property evaluation

The silicone pressure-sensitive adhesive compositions of Examples 1 to 12 and Comparative Examples 1 to 18 and the physical properties of the cured product prepared therefrom were measured in the following manner, and the results are shown in Table 5.

(1) viscosity

The viscosity of the silicone pressure-sensitive adhesive composition was measured at 25° C. using a Brookfield viscometer (LV type).

(2) hardness

The silicone pressure-sensitive adhesive composition was put in an aluminum foil chalet and heated at 150° C. for 1 hour to cure to make a cured product having a thickness of 6 mm. The hardness of the cured product was measured using a type OO Durometer (Shore OO).

(3) adhesion

The silicone pressure-sensitive adhesive composition was applied to a PET film having a thickness of 50 μm, and cured by heating at 120° C. for 2 minutes to obtain an adhesive tape having an adhesive layer having a width of 25 mm and a thickness of 150 μm. The glass specimen was placed in contact with the adhesive layer of the adhesive tape, adhered using a rubber roller having a load of 2 kgf, and allowed to stand at room temperature for 1 hour to prepare a specimen. A peel test was performed on the specimen at a rate of 100 mm/min in the 180° direction through a tensile tester to measure adhesive strength.

(4) gel migration to glass

After measuring the adhesive force as in item (3), the presence or absence of gel migration to the glass specimen (whether residue of the adhesive layer remained on the glass specimen as an adherend) was visually checked.

Viscosity (mPa·s) Hardness (Shore OO) Adhesion (N/25mm) Gel migration to glass Example 1 3,030 14 8.6 none Example 2 3,200 12 5.2 none Example 3 2,870 15 20.0 none Example 4 2,710 17 25.0 none Example 5 4,120 13 4.1 none Example 6 5,080 12 5.2 none Example 7 4,250 11 7.3 none Example 8 1,840 16 7.5 none Example 9 6,320 10 3.2 none Example 10 2,340 15 27.0 none Example 11 2,740 12 3.6 none Example 12 8,410 10 7.3 none Comparative Example 1 4,690 8 1.3 none Comparative Example 2 2,180 14 26.0 has exist Comparative Example 3 7,630 6 1.0 none Comparative Example 4 4,920 10 3.3 has exist Comparative Example 5 2,650 12 24.3 has exist Comparative Example 6 3,340 9 1.8 none Comparative Example 7 2,640 12 2.9 has exist Comparative Example 8 2,480 17 6.3 has exist Comparative Example 9 8,630 6 2.0 has exist Comparative Example 10 5,060 7 2.2 none Comparative Example 11 6,210 5 18.6 has exist Comparative Example 12 11,100 3 15.2 has exist Comparative Example 13 5,590 11 2.9 has exist Comparative Example 14 1,810 12 5.2 has exist Comparative Example 15 770 5 8.7 has exist Comparative Example 16 750 11 2.3 none Comparative Example 17 2,000 8 4.6 has exist Comparative Example 18 1,470 16 7.5 has exist

As shown in Table 5, the compositions of Examples 1 to 12 have appropriate viscosity, and the cured product prepared therefrom has excellent hardness and adhesive strength, and there is no residue on the adherend after peeling, indicating excellent reworkability. Could know.

On the other hand, Comparative Examples 1 and 6, in which the content of the first organopolysiloxane is insufficient, and Comparative Example 10, which includes an excessive amount of the first diorganopolysiloxane, lack adhesive strength. Furthermore, Comparative Examples 11 and 12, in which the total amount of diorganopolysiloxane is insufficient, are remarkably insufficient in hardness. In addition, Comparative Example 2 containing an excess of the first organopolysiloxane, Comparative Examples 4 and 5 containing a small amount of the second organopolysiloxane, Comparative Example 7, the second diorgano containing an excess of the second organopolysiloxane Comparative Examples 8 and 9 containing an excessive amount or a small amount of polysiloxane had insufficient reworkability as a residue remained on the adherend after peeling. Further, Comparative Example 13 containing no second organopolysiloxane, Comparative Example 15 containing no diorganopolysiloxane, and Comparative Examples 16 and 17 containing one type of organopolysiloxane and one type of diorganopolysiloxane, and the second In Comparative Example 18, which did not contain diorganopolysiloxane, a residue remained on the adherend after peeling, resulting in insufficient reworkability.

Claims (7)

A first organopolysiloxane, a second organopolysiloxane, a first diorganopolysiloxane, a second diorganopolysiloxane, a diorgano hydrogen siloxy-terminated polyorganosiloxane and a catalyst,
The first organopolysiloxane is an R ¹ ₃ SiO _1/2 unit (wherein R ¹ is a substituted or unsubstituted C _1-10 alkyl group, or a hydroxyl group, and R ¹ may be the same or different, respectively.) Contains SiO ₂ units,
The second organopolysiloxane is R ² R ³ ₂ SiO _1/2 unit (in the formula, R ² is a substituted or unsubstituted C _2-10 alkenyl group, R ³ is a substituted or unsubstituted C _1-10 alkyl group ), R ⁴ ₃ SiO _1/2 unit (in the formula, R ⁴ is a substituted or unsubstituted C _1-10 alkyl group.) and SiO ₂ units,
The first diorganopolysiloxane and the second diorganopolysiloxane have at least two alkenyl groups in one molecule,
The first diorganopolysiloxane has a viscosity at 25° C. lower than that of the second diorganopolysiloxane, a silicone pressure-sensitive adhesive composition. The method according to claim 1,
The first organopolysiloxane is represented by the following formula (1), a number average molecular weight of 500 to 10,000 g / mol, silicone pressure-sensitive adhesive composition:
[Formula 1]
(R ¹ ₃ SiO _1/2 ) _a (SiO ₂ ) _b
In Formula 1,
a+b is 1, and a/b is 0.1 to 2.0. The method according to claim 1,
The second organopolysiloxane is represented by the following formula (2), silicone pressure-sensitive adhesive composition:
[Formula 2]
(R ² R ³ ₂ SiO _1/2 ) _c (R ⁴ ₃ SiO _1/2 ) _d (SiO ₂ ) _e
In formula 2,
c is from 0.03 to 0.25,
d is 0.1 to 0.5,
e is between 0.35 and 0.65. The method according to claim 1,
The first diorganopolysiloxane is represented by the following formula (3), silicone pressure-sensitive adhesive composition:
[Formula 3]
(R ⁵ R ⁶ ₂ SiO _1/2 ) ₂ (R ⁷ R ⁸ SiO) _f (R ⁹ ₂ SiO) _g
In formula 3,
R ⁵ is substituted or unsubstituted C _2-10 alkenyl,
R ⁶ is substituted or unsubstituted C _1-10 alkyl,
R ⁷ is substituted or unsubstituted C _1-10 alkyl or substituted or unsubstituted C _2-10 alkenyl,
R ⁸ and R ⁹ are each independently substituted or unsubstituted C _1-6 alkyl or substituted or unsubstituted C _6-10 aryl,
f and g are each independently an integer of 0 or 1 or more,
f/(f+g) is from 0 to 0.1. The method according to claim 1,
The second diorganopolysiloxane is represented by the following formula (4), silicone pressure-sensitive adhesive composition:
[Formula 4]
(R ¹⁰ R ¹¹ ₂ SiO _1/2 ) ₂ (R ¹² R ¹³ SiO) _h (R ¹⁴ ₂ SiO) _i
In formula 4,
R ¹⁰ is substituted or unsubstituted C _2-10 alkenyl,
R ¹¹ is substituted or unsubstituted C _1-10 alkyl,
R ¹² is substituted or unsubstituted C _1-10 alkyl or substituted or unsubstituted C _2-10 alkenyl,
R ¹³ and R ¹⁴ are each independently substituted or unsubstituted C _1-6 alkyl or substituted or unsubstituted C _6-10 aryl,
h and i are each independently 0 or an integer of 1 or more,
h/(h+i) is 0 to 0.1. The method according to claim 1,
The diorgano hydrogen siloxy-terminated polyorganosiloxane includes at least two hydrogen groups directly bonded to a silicon atom in one molecule, and has a viscosity of 10 to 3,000 mPa·s at 25°C. The method according to claim 1,
The composition comprises 25 to 75 parts by weight of the first organopolysiloxane, 4 to 16 parts by weight of the second organopolysiloxane, 5 to 65 parts by weight of the first diorganopolysiloxane, 5 to 20 parts by weight of the second diorganopolysiloxane and 1 to 10 A silicone pressure-sensitive adhesive composition comprising a part by weight of diorgano hydrogen siloxy-terminated polyorganosiloxane.