JP6691802B2 - Silicone adhesive composition and adhesive tape - Google Patents

Description

  The present invention relates to a silicone pressure-sensitive adhesive composition and a pressure-sensitive adhesive tape applied to a plastic film, and in particular, a plastic film coated with the silicone pressure-sensitive adhesive composition is attached to a metal plate or the like, for example, in a reflow system. The present invention relates to a silicone pressure-sensitive adhesive composition capable of peeling a plastic film without leaving an adhesive residue on the surface of a metal plate or the like even when exposed to high temperatures during soldering, and a pressure-sensitive adhesive tape coated with the same.

Conventionally, a silicone pressure-sensitive adhesive composition that can be peeled off cleanly without sticking residue even when it is pasted or masked on an adherend such as metal, especially stainless steel, and has been exposed to a high temperature history of 300 ° C (Patent Document 1). The silicone adhesive composition contains (A) 20 to 80 parts by weight of an alkenyl group-containing polydiorganosiloxane, (B) R ¹ ₃ SiO _0.5 units and SiO ₂ units, and R ¹ ₃ SiO _0.5 units. Polyorganosiloxane in which the molar ratio of / SiO ₂ units is 0.6 to 1.7 (R1 is a monovalent hydrocarbon group having 1 to 10 carbon atoms) 80 to 20 parts by weight, (C) a poly containing a SiH group Organosiloxane Amount in which the molar ratio of the SiH group in the component (C) to the alkenyl group in the component (A) is 0.5 to 20, the total amount of the (D) control agent (A) and the (B) component is 100 parts by weight. To 0 to 5.0 parts by weight, (E) platinum catalyst (A), 1 to 5,000 ppm as platinum content relative to the total of (B) components, (F) carbon black (A), (B) 0.1 to 50 parts by weight per 100 parts by weight It is a silicone pressure-sensitive adhesive composition characterized by containing parts.

In addition, an adhesive tape and an adhesive layer of the adhesive tape which can be peeled off neatly without leaving an adhesive residue even when exposed to a high temperature of 250 ° C. or more when adhered to an adherend such as metal A silicone composition for pressure-sensitive adhesives has been proposed (Patent Document 2). The silicone composition for pressure-sensitive adhesive comprises a polyorganosiloxane having an alkenyl group, a polyorganosiloxane having R ¹ ₃ SiO _0.5 units and a SiO ₂ unit, and a polyorganosiloxane having a SiH group. A silicone composition for an agent, comprising: (1) applying the composition onto a base tape so that the thickness after curing is 28 to 32 μm, and then heating at 110 ° C. to 140 ° C. for 1 to 3 minutes. After the pressure-sensitive adhesive tape was prepared, (2) after the pressure-sensitive adhesive side of the pressure-sensitive adhesive tape was pressure-bonded to the stainless steel surface, it was heated at a maximum temperature of 250 ° C to 300 ° C for at least 10 minutes, and then (3) after cooling to room temperature. When the adhesive tape is manually peeled off from the stainless steel and the surface of the stainless steel is visually observed, a residue derived from the silicone composition is left on the surface of the stainless steel. An adhesive agent for a silicone composition, characterized in that not observation.

Further, there has been proposed a silicone-based pressure-sensitive adhesive that forms a pressure-sensitive adhesive layer having good re-peelability after being exposed to a high temperature (Patent Document 3). The silicone-based pressure-sensitive adhesive comprises (A) (a) a raw rubber-like organopolysiloxane having an average of one or more alkenyl groups in one molecule, and (b) an R ¹ ₃ SiO _1/2 unit (in the formula, R1 is a substituted or unsubstituted monovalent hydrocarbon group) and a SiO _4/2 unit, and the molar ratio of the R ¹ ₃ SiO _1/2 unit to the SiO _4/2 unit is 0.5 to 0.5. A mixture of 1.5 organopolysiloxane resins, or a partial condensation reaction product of the components (a) and (b), and (B) an organo having an average of two or more silicon-bonded hydrogen atoms in one molecule. Polysiloxane {amount in which silicon atom-bonded hydrogen atoms in this component are 0.5 to 150.0 mol per 1 mol of alkenyl group in component (A)}, (C) aromatic amine compound and / or Aromatic amino group-containing organosilver Silicone pressure sensitive adhesive comprising at least 0.001 to 10 parts by weight per 100 parts by weight of the component (A), and (D) a platinum catalyst (a sufficient amount to cure the composition). is there.

Further, there has been proposed a silicone-based pressure-sensitive adhesive composition capable of forming a pressure-sensitive adhesive layer in which a silicone component is not observed on an adherend when it is adhered to a metal or the like and peeled off after being exposed to a high temperature (Patent Reference 4). The silicone-based pressure-sensitive adhesive composition has a molecular formula (A):
(R ₃ SiO _1/2 ) _4-p (R ¹ R ₂ SiO _1/2 ) _p (R ₂ SiO) _m (RR ¹ SiO) _n (SiO _4/2 ) (1)
(In the formula, R is a monovalent hydrocarbon group having 1 to 10 carbon atoms and having no aliphatic unsaturated bond or a monovalent halogenated hydrocarbon group, and R ¹ is an alkenyl group having 2 to 10 carbon atoms. , P is an average number in the range of 2 to 4, m is an average number in the range of 1500 to 10000, n is an average number of 0 or more, m> n, and m + n is an average of 1500 to 10000. Of 100 to 100 parts by weight of a branched organopolysiloxane having at least two alkenyl groups on average in the molecular chain terminal, and (B) R ³ R ² _{2 2} SiO _1/2 unit (formula). R ² is an alkyl group having 1 to 10 carbon atoms, R ³ is an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, or a hydroxyl group, which is a) and _{SiO 4/2} Consists of a ^position, organopolysiloxane resin molar ratio of _R ³ R ₂ 2 _{SiO 1/2} units and _{SiO 4/2} units is 0.6 to 1.7: 10 to 400 parts by weight, (C) 1 molecule Organohydrogenpolysiloxane having 2 or more silicon-bonded hydrogen atoms therein: The molar ratio of silicon-bonded hydrogen atoms in this component to alkenyl groups in the components (A) and (B) is 1.0 to A silicone-based pressure-sensitive adhesive composition, characterized in that the amount thereof is 60 and (D) platinum catalyst: catalyst amount.

JP, 2004-168808, A JP 2005-298550 A JP, 2005-23300, A JP, 2009-51916, A

  However, the silicone pressure-sensitive adhesive composition according to Patent Document 1 has a problem that transparency may be low because the composition contains carbon black, and the silicone composition for pressure-sensitive adhesive according to Patent Document 2 and Patent Document 4 The silicone-based pressure-sensitive adhesive composition according to (1) has a problem that the adhesive force is low, and furthermore, the silicone-based pressure-sensitive adhesive according to Patent Document 3 contains an aromatic amine compound and thus is yellow and transparent as a whole. There is a problem that the property is low.

  The problem to be solved by the present invention is a silicone pressure-sensitive adhesive composition which has no coloring such as yellowish color and has high transparency and high adhesive strength, and does not cause adhesive residue even when it is adhered to a metal or the like and exposed to high temperature. The object is to provide a product and an adhesive tape coated with the product.

In order to solve the above problems, the invention according to claim 1 is
The polydiorganosiloxane having an alkenyl group contains 20 to 60 parts by weight, R ₃ SiO _1/2 unit and SiO _4/2 unit, and the molar ratio of R ₃ SiO _1/2 unit to SiO _4/2 unit is 0. 40 to 80 parts by weight of polyorganosiloxane of 0.5 to 1.5 (R is a monovalent hydrocarbon group having 1 to 10 carbon atoms), and an amount such that the molar ratio to the polydiorganosiloxane is 0.5 to 20. Of polyorganohydrogensiloxane, 0 to 5.0 parts by weight of a reaction inhibitor based on 100 parts by weight of a total of polydiorganosiloxane and polyorganosiloxane, a curing catalyst necessary for the addition reaction, and the following formula (1):
(In the formula, at least one of R ¹ is a compound represented by the following formula (2),
^{_{(R 3 O) 3 Si-}} R 2 - (2)
R ² in the formula (2) is an alkylene group having 2 to 5 carbon atoms, R ³ is a monovalent alkyl group having 1 to 8 carbon atoms, and the other R ^1's each independently have 1 to 8 carbon atoms, An alkyl group, an aryl group, an aralkyl group, or a monofunctional alkenyl group)
Isocyanuric acid derivative represented in the contained, and 0.2 to 2.0 parts by weight based on 100 parts by weight of polydiorganosiloxane polyorganosiloxane, the amount of the polio Lugano siloxane and the polydiorganosiloxane relationship of the amount ratio of the provides a silicone adhesive composition which is a polio Lugano siloxane / polydiorganosiloxane = 2.00 to 1.33.

  The invention according to claim 2 is characterized in that the curing catalyst required for the addition reaction is 1 to 5000 ppm with respect to the total amount of polydiorganosiloxane and polyorganosiloxane. Provide things.

The invention according to claim 3 is the silicone pressure-sensitive adhesive composition according to any one of claims 1 and 2 , wherein the isocyanuric acid derivative is tris [3- (trimethoxysilyl) propyl] isocyanurate. provide.

  The silicone pressure-sensitive adhesive composition and pressure-sensitive adhesive tape of the present invention are free from coloring such as yellowish color, have high transparency, have high adhesive strength, and have no adhesive residue even when adhered to metal or the like and exposed to high temperature. effective.

  Hereinafter, the silicone pressure-sensitive adhesive composition according to the present invention will be specifically described.

<Polydiorganosiloxane>
The polydiorganosiloxane used in the present invention is a polydiorganosiloxane having at least one alkenyl group, and the alkenyl group is a vinyl group, an allyl group, a propenyl group or an isopropenyl group which reacts with a SiH group by a hydrosilylation reaction. A carbon-carbon double bond such as a butenyl group, an isobutenyl group and a hexenyl group. The properties of the polydiorganosiloxane are liquid or raw rubber, and the viscosity at 25 ° C. is preferably 50 mPa · s or more. If it is less than 50 mPa · s, the curing after coating on the plastic film will be insufficient. When used, two or more kinds may be mixed. The amount of the polydiorganosiloxane compounded is preferably 20 to 60 parts by weight based on 100 parts by weight of the entire composition. If it is less than 20 parts by weight, the adhesive strength will be insufficient, and if it exceeds 60 parts by weight, the work when coating a plastic film or the like will be performed. The sex becomes insufficient.

<Polyorganosiloxane>
The polyorganosiloxane used in the present invention is a polyorganosiloxane in which the molar ratio of R ₃ SiO _1/2 unit to SiO _4/2 unit is 0.5 to 1.5. The molar ratio is 0.5
If it is less than 1.5 or more than 1.5, the adhesive force may decrease. The polyorganosiloxane may be a polyorganosiloxane containing SiOH groups in its composition. In this case, the OH group content is preferably less than 4.0% by weight, and when it exceeds 4.0% by weight, curability is deteriorated. To do. The compounding amount of the polyorganosiloxane is preferably 40 to 80 parts by weight based on 100 parts by weight of the entire composition, and the relationship between the compounding amount of the polyorganosiloxane and the compounding amount of the above polydiorganosiloxane is polyorganosiloxane / polydiorgano Siloxane = 40 / 20-80 / 60 is preferable .

<Polyorganohydrogen siloxane>
The polyorganohydrogensiloxane used in the present invention is a polyorganohydrogensiloxane having an SiH group in one molecule and having a molar ratio of 0.5 to 20 with respect to the polydiorganosiloxane. Examples of the organo group bonded to the silicon atom include a methyl group, an ethyl group and a phenyl group. If the molar ratio is less than 0.5 or more than 20, the adhesive strength may decrease.

<Reaction inhibitor>
The reaction inhibitor used in the present invention is 0 to 5.0 parts by weight based on 100 parts by weight of the total of polydiorganosiloxane and polyorganosiloxane, and specifically, 3-methyl-1-butyne-3-. All, 3-methyl-1-pentyn-3-ol, 3,5-dimethyl-1-hexyne-3-ol, 1-ethynylcyclohexanol, 3-methyl-3-trimethylsiloxy-1-butyne, 3-methyl -3-trimethylsiloxy-1-pentyne, 3,5-dimethyl-3-trimethylsiloxy-1-hexyne, 1-ethynyl-1-trimethylsiloxycyclohexane, bis (2,2-dimethyl-3-butynoxy) dimethylsilane, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, 1,1,3,3-tetramethyl-1 3-divinyl siloxane or the like can be used.

<Curing catalyst required for addition reaction>
The curing catalyst required for the addition reaction used in the present invention is added to accelerate the hydrosilylation reaction of the polydiorganosiloxane, the organohydrogenpolysiloxane, and the alkenyl group that may be contained in the isocyanuric acid derivative shown below, Known metals, metal compounds, metal complexes and the like having a catalytic activity for the hydrosilylation reaction can be used. It is particularly preferable to use platinum, a platinum compound, or a complex thereof. These catalysts may be used alone or in combination of two or more. Moreover, you may use a cocatalyst together. The amount of the curing catalyst blended is preferably 1 to 5000 ppm, more preferably 5 to 3000 ppm, based on the total amount of polydiorganosiloxane and polyorganosiloxane. If it is less than 1 ppm, the curability is deteriorated and it is difficult to obtain a sufficient adhesive force, and if it exceeds 5000 ppm, the transparency after curing may be deteriorated.

<Isocyanuric acid derivative>
The isocyanuric acid derivative used in the present invention is a compound represented by the above formula (1), wherein at least one R ^{1 in} the formula (1) is a compound represented by the following formula (2),
_{^{(R 3 O) 3 Si-}} R 2 - (2)
R ² in the formula (2) is an alkylene group having 2 to 5 carbon atoms, R ³ is a monovalent alkyl group having 1 to 8 carbon atoms, and the other R ^1's each independently have 1 to 8 carbon atoms, An alkyl group, an aryl group, an aralkyl group, or a monofunctional alkenyl group)
The isocyanuric acid derivative is preferably blended in an amount of 0.2 to 2.0 parts by weight based on 100 parts by weight of the total of polydiorganosiloxane and polyorganosiloxane. Less than 0.2 part by weight, 2.0 weight part exceeds some cases adhesive residue upon exposure to high temperatures occurs.

  The composition may further contain an antioxidant in order to further improve heat resistance. As the antioxidant, those generally used can be used. For example, in addition to the hindered phenol type, phosphorus type, hindered amine type and thioether type antioxidants can be mentioned. The content of the antioxidant is preferably 0.0001 to 1 part by weight based on 100 parts by weight of the total of polydiorganosiloxane, polyorganosiloxane and polyorganohydrogensiloxane.

  Further, in order to reduce the viscosity of the present composition when applied to the plastic film shown below, toluene, an aromatic solvent such as xylene, hexane, octane, an aliphatic solvent such as isoparaffin, methyl ethyl ketone, methyl isobutyl ketone, etc. The above-mentioned ketone-based solvent, ester-based solvent and the like can be added.

  In the pressure-sensitive adhesive tape according to claim 3 of the present invention, the silicone pressure-sensitive adhesive composition according to claim 1 or 2 is polyester (PET (polyethylene terephthalate)), polytetrafluoroethylene, polyimide, polyphenylene. Sulfide, polyamide, polycarbonate, polystyrene, polypropylene, polyethylene, at least one surface of the plastic film such as polyvinyl chloride, comma coater, lip coater, roll coater, die coater, knife coater, blade coater, rod coater, kiss coater, gravure coater, It is applied by screen coating, dip coating, cast coating or the like so that the thickness after curing becomes a thin layer having a uniform thickness of about 1 to 200 μm, and then cured.

  Next, the silicone adhesive composition of the present invention will be described in detail with reference to Examples and Comparative Examples.

<Example>
As a polydiorganosiloxane, both ends are blocked with trimethylsiloxy groups, and a molecular weight (MW) containing an alkenyl group bonded to a Si atom in the molecular chain is about 660,000, 40 parts by weight of dimethylpolysiloxane, and at room temperature as a polyorganosiloxane. It is composed of (CH ₃ ) ₃ SiO _1/2 units (M units) and SiO _4/2 units (Q units), which are rubbery, and have a molecular weight (MW) of about 8,000 and a molar ratio of M units / Q units. 60 parts by weight of 0.75 polysiloxane, as a polyorganohydrogensiloxane, a dimethylhydrogenpolysiloxane having a molecular weight (MW) of about 1,600, in which both ends are blocked with trimethylsiloxy groups and the hydrogen chains bonded to Si atoms are contained in the molecular chain. 0.4 parts by weight of siloxane, 0.3 parts by weight of 1-ethynylcyclohexanol as a reaction inhibitor, a curing catalyst necessary for addition reaction 0.15 parts by weight of platinum-vinyl dimer complex (Pt: 2% wt), 1.0 part by weight of isocyanuric acid tris [3- (trimethoxysilyl) propyl] isocyanuric acid derivative, and toluene are mixed, An example of a silicone adhesive composition was obtained in which the weight% of toluene was 50%.

<Comparative Example 1>
The silicone pressure-sensitive adhesive composition of Comparative Example 1 was prepared in the same manner as in Example 1 except that tris [3- (trimethoxysilyl) propyl] isocyanurate was not blended.

<Comparative example 2>
A silicone pressure-sensitive adhesive composition of Comparative Example 2 was prepared in the same manner as in Example 2 except that the compounding amount of tris [3- (trimethoxysilyl) propyl] isocyanurate was 5 parts by weight.

<Comparative example 3>
Bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate (manufactured by Johoku Chemical Co., Ltd., product) was added with 1.0 part by weight of tris [3- (trimethoxysilyl) propyl] isocyanurate compounded in the examples. Name: JF-95) The silicone pressure-sensitive adhesive composition of Comparative Example 3 was prepared in the same manner as in Example except that the amount was changed to 1.0 part by weight.

<Comparative example 4>
Implemented except that 1.0 part by weight of tris [3- (trimethoxysilyl) propyl] isocyanurate compounded in the example was replaced with 1.0 part by weight of diallyl monoglycidyl isocyanurate (DA-MGIC manufactured by Shikoku Kasei Co., Ltd.). The silicone pressure-sensitive adhesive composition of Comparative Example 4 was prepared in the same manner as the example.

<Evaluation item and evaluation method>

<Adhesive strength>
The silicone pressure-sensitive adhesive compositions of Examples and Comparative Examples 1 to 4 were applied to a PET film having a thickness of 75 μm and a width of 25 mm so that the thickness after curing would be 50 μm, and heated at 130 ° C. for 3 minutes. It was cured to prepare an adhesive tape. This adhesive tape was attached to a SUS plate (SUS304), and a roller covered with a rubber layer having a weight of 2 kg was reciprocated once and allowed to stand at room temperature, and then 180 ° at a speed of 300 mm / min using a tensile tester. The force (N / 25 mm) required to peel off the adhesive tape from the SUS plate at the angle of was measured.

<Total light transmittance>
The silicone pressure-sensitive adhesive compositions of Examples and Comparative Examples 1 to 4 were applied to a PET film having a thickness of 75 μm and a width of 25 mm so that the thickness after curing would be 50 μm, and heated at 130 ° C. for 3 minutes. It was cured to prepare an adhesive tape. The total light transmittance (%) according to JIS K7136 of this adhesive tape was measured using Haze Guard II (manufactured by Toyo Seiki Seisaku-sho, Ltd.).

<Yellowish>
The silicone pressure-sensitive adhesive compositions of Examples and Comparative Examples 1 to 4 were applied to a PET film having a thickness of 75 μm and a width of 25 mm so that the thickness after curing would be 50 μm, and heated at 130 ° C. for 3 minutes. It was cured to prepare an adhesive tape. The b value (degree of yellowness) of this adhesive tape was measured with a color difference meter (CM-2600d, manufactured by Konica Minolta Sensing Co., Ltd.).

<Adhesive residue>
The silicone pressure-sensitive adhesive compositions of Examples and Comparative Examples 1 to 4 were applied to a polyimide film having a thickness of 20 μm and a width of 25 mm using an applicator so that the thickness after curing would be 50 μm, and then 130 ° C. The adhesive tape was prepared by heating and curing under the condition of 3 minutes. This pressure-sensitive adhesive tape was attached to a metal plate (SUS304: polished stainless steel plate) and pressure-bonded by reciprocating a roller covered with a rubber layer having a weight of 2 kg once, and then left in a dryer at 250 ° C. for 30 minutes. .. After a predetermined time, the metal plate was taken out, cooled to room temperature, the adhesive tape was peeled off, and it was confirmed by finger touch whether the adhesive layer remained on the surface of the metal plate. The case where the adhesive layer remained was evaluated as ×, and the case where the adhesive layer did not remain was evaluated as ○.

<Evaluation result>
The evaluation results are shown in Table 1.

Claims (3)

The polydiorganosiloxane having an alkenyl group contains 20 to 60 parts by weight, R ₃ SiO _1/2 unit and SiO _4/2 unit, and the molar ratio of R ₃ SiO _1/2 unit to SiO _4/2 unit is 0. 40 to 80 parts by weight of polyorganosiloxane of 0.5 to 1.5 (R is a monovalent hydrocarbon group having 1 to 10 carbon atoms), and an amount such that the molar ratio to the polydiorganosiloxane is 0.5 to 20. Of polyorganohydrogensiloxane, 0 to 5.0 parts by weight of a reaction inhibitor based on 100 parts by weight of a total of polydiorganosiloxane and polyorganosiloxane, a curing catalyst necessary for the addition reaction, and the following formula (1):
(In the formula, at least one of R ¹ is a compound represented by the following formula (2),
^{_{(R 3 O) 3 Si-}} R 2 - (2)
R ² in the formula (2) is an alkylene group having 2 to 5 carbon atoms, R ³ is a monovalent alkyl group having 1 to 8 carbon atoms, and the other R ^1's each independently have 1 to 8 carbon atoms, An alkyl group, an aryl group, an aralkyl group, or a monofunctional alkenyl group)
Isocyanuric acid derivative represented in the contained, and 0.2 to 2.0 parts by weight based on 100 parts by weight of polydiorganosiloxane polyorganosiloxane, the amount of the polio Lugano siloxane and the polydiorganosiloxane relationship of the amount ratio of the silicone pressure sensitive adhesive composition which is a polio Lugano siloxane / polydiorganosiloxane = 2.00 to 1.33.   The silicone pressure-sensitive adhesive composition according to claim 1, wherein the curing catalyst required for the addition reaction is 1 to 5000 ppm with respect to the total amount of polydiorganosiloxane and polyorganosiloxane. The silicone pressure-sensitive adhesive composition according to claim 1, wherein the isocyanuric acid derivative is tris [3- (trimethoxysilyl) propyl] isocyanuric acid.