Silicone-based pressure-sensitive adhesive composition for difficult-to-bond materials

Abstract

To provide a silicone-based adhesive composition corresponding to a hardly adhesive article which exhibits stable adhesiveness for various fiber base materials to an airbag base fabric subjected to silicone treatment, is easily peelable from the base fabric at the time of peeling, and prevents component transition to the base fabric.SOLUTION: A silicone-based adhesive composition contains: 30-70 pts.mass of organopolysiloxane (A) having at least two alkenyl groups in one molecule; 70-30 pts.mass of an organopolysiloxane resin (B) which is composed of a R13SiO1 / 2 unit, in the formula, R1 is a halogen substituted or unsubstituted monovalent hydrocarbon group, and a SiO4 / 2 unit, and has a molar ratio of a R13SiO1 / 2 unit to the SiO4 / 2 unit of 0.5 or more and 1.5 or less; and a silicone compound (C) having three hydrogen atoms bonding to a silicon atom in one molecule and having a mass average molecular weight of 1,000 or less, in which the hydrogen atoms bonding to the silicon atom is 0.5-20 mols with respect to 1 mol of the total of the alkenyl groups of the component (A), and 0.1-1,000 ppm of a platinum-based catalyst (D) is contained with respect to the total of (A), (B) and (C) as a platinum group on a mass basis.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a silicone-based pressure-sensitive adhesive composition that exhibits stable adhesiveness to a silicone-treated airbag base fabric for various fiber substrates and has no component transfer to the base fabric, which is suitable for difficult-to-adhere materials.

Background Art

[0002] As a safety device for automobiles, in the event of a collision accident, a sensor senses the impact, generates high-temperature and high-pressure gas from an inflator, and rapidly deploys the airbag with this gas to prevent the bodies of the driver and passengers, particularly the head, from colliding with the steering wheel, windshield, door glass, etc. In recent years, it has become common for automobiles to be equipped with multiple airbags, such as not only driver and passenger airbags but also knee airbags, side airbags, curtain airbags, etc.

[0003] Generally, a base fabric woven from synthetic fibers is used for airbags. As the synthetic fiber, polyamide fibers such as nylon 66, nylon 6, nylon 46, and nylon 12 are often used. When these fabrics are used as they are, they are referred to as non-coated base fabrics, and when coated with silicone, they are referred to as coated base fabrics.

[0004] Patent Document 1 is a publication regarding a coated base fabric for airbags that ensures sufficient low air permeability. In terms of low air permeability, the latter has higher performance than the non-coated base fabric and the coated base fabric.

[0005] The coated base fabric coated with silicone has high low air permeability performance. On the other hand, since silicone has a low surface free energy, it is very difficult to adhere, and it is not an exaggeration to say that it is a difficult-to-adhere material.

[0006] Patent Document 2 relates to a silicone rubber composition for a sewing airbag caulking material that is used as a caulking material at the location where the base fabrics of an airbag formed in a bag shape by overlapping and sewing the treated surfaces of coating base fabrics coated with silicone, which is a difficult-to-adhere material, are overlapped and sewn, exhibits excellent adhesiveness to the base fabric, and is excellent in storage stability and heat resistance change after curing. In this case, it is required that the caulking material cannot be easily peeled off.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

[0008] There is also a method of use for adhering a base fabric coated with silicone, which is a difficult-to-adhere material, as in Patent Document 2. However, it may be used in a way such as temporarily attaching a label or the like and peeling it off later, or it may be used as an adhesive tape. Patent Document 3 is a publication regarding a silicone pressure-sensitive adhesive having high adhesiveness to a low-energy base material. There was room for improvement in terms of adhesiveness to a coating base fabric coated with silicone, which is a difficult-to-adhere material, and component transfer to the base material. Patent Document 4 is a publication regarding a silicone rubber composition that cures rapidly by heating at a low temperature. There was room for improvement in terms of adhesiveness to a coating base fabric coated with silicone, which is a difficult-to-adhere material, and component transfer to the base material, with respect to a compound having a silicon atom-bonded hydrogen atom.

Summary of the Invention

Problems to be Solved by the Invention

[0009] To obtain a silicone-based pressure-sensitive adhesive composition that exhibits stable adhesiveness to various fiber substrates on a silicone-treated airbag base fabric, can be easily peeled off from the base fabric when peeled, and has no component transfer to the base fabric.

Means for Solving the Problems

[0010] 30 to 70 parts by mass of an organopolysiloxane (A) having at least 2 alkenyl groups in one molecule, R 1 3SiO 1 / 2 units (wherein R 1 is a halogen-substituted or unsubstituted monovalent hydrocarbon group.), and SiO 4 / 2 units, and the molar ratio of R 4 / 2 to SiO 1 3SiO 1 / 2 units is 0.5 or more and 1.5 or less. 70 to 30 parts by mass of an organopolysiloxane resin (B), and a silicone compound (C) having 3 silicon-bonded hydrogen atoms in one molecule and a mass average molecular weight of 1,000 or less, with respect to a total of 1 mol of the alkenyl groups of the component (A), the silicon-bonded hydrogen atoms being 0.5 to 20 mol, and a platinum-based catalyst (D) in an amount of 0.1 to 1,000 ppm by mass as the platinum content with respect to the total of (A), (B), and (C). A silicone-based pressure-sensitive adhesive composition.

Advantages of the Invention

[0011] The silicone-based pressure-sensitive adhesive composition of the present application exhibits stable adhesiveness to a coating base fabric coated with silicone, which is a difficult-to-adhere material, can be easily peeled off from the base fabric when peeled, and has no component transfer to the base fabric. Therefore, labels and the like do not peel off during the movement of airbag production, etc., and the appearance and touch of the base fabric are excellent even after peeling.

Embodiments for Carrying Out the Invention

[0012] Hereinafter, the silicone-based pressure-sensitive adhesive composition for difficult-to-adhere materials according to the invention of the present application will be specifically described. Note that organopolysiloxane (A), organopolysiloxane (B), and silicone compound (C) are silicone compounds in a broad sense.

[0013] <Organopolysiloxane (A)> Organopolysiloxane (A) has at least 2 alkenyl groups in one molecule. Although organopolysiloxane (A) is not particularly limited, an oily one showing a viscosity of 1,000 mPa·s or more, or a silicone gum from semi-solid to solid can be used. The addition amount is 30 to 70 parts by mass, more preferably 35 to 65 parts by mass. Note that when using a silicone gum, the silicone-based pressure-sensitive adhesive composition for difficult-to-adhere materials can also be diluted with a solvent described later.

[0014] <Organopolysiloxane (B)> Organopolysiloxane (B) is composed of R 1 3SiO 1 / 2 units (wherein R 1 is a halogen-substituted or unsubstituted monovalent hydrocarbon group.) and SiO 4 / 2 units, and is an organopolysiloxane resin in which the molar ratio of R 4 / 2 3SiO 1 units to SiO 1 / 2 units is 0.5 or more and 1.5 or less. The addition amount is 30 to 70 parts by mass, more preferably 35 to 65 parts by mass.

[0015] <Silicone compound (C)> Silicone compound (C) is a compound having a silicon atom-bonded hydrogen atom, so-called hydrogen silicone. There are 3 silicon atom-bonded hydrogen atoms in one molecule, and the mass average molecular weight is 1,000 or less. Examples of silicone compound (C) are shown in formula (1) and formula (2). JPEG0007698567000001.jpg4544 Formula (1) R 1 is an organic group including a non-substituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms JPEG0007698567000002.jpg4150 Formula (2) R2 is an organic group including a non-substituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms As the addition amount, the silicon atom-bonded hydrogen atom is 0.5 to 20 moles, more preferably 1 to 15 moles, per 1 mole of the total alkenyl groups of the organopolysiloxane (A).

[0016] <Platinum-based catalyst (D)> The platinum-based catalyst (D) is an addition reaction catalyst, and examples thereof include chloroplatinic acid, an alcohol solution of chloroplatinic acid, a reaction product of chloroplatinic acid and alcohol, a reaction product of chloroplatinic acid and an olefin compound, a reaction product of chloroplatinic acid and a vinyl group-containing siloxane, a platinum-olefin complex, a platinum-vinyl group-containing siloxane complex, a rhodium complex, and a ruthenium complex. Further, those obtained by dissolving or dispersing these in a solvent such as isopropanol or toluene or in a silicone oil may be used. As the addition amount, the platinum amount is 0.1 to 1000 ppm, more preferably 10 to 500 ppm, based on the total of (A), (B), and (C) on a mass basis.

[0017] <Reaction regulator> In the silicone-based pressure-sensitive adhesive composition of the present application, acetylene alcohols can be added as a reaction regulator. Examples of the reaction regulator include 1-ethynylcyclohexanol, 3,5-dimethyl-1-hexyn-3-ol, 3-methyl-1-butyn-3-ol, and 1-phenyl-2-propyn-1-ol. As the addition amount, the organopolysiloxane (A) having at least 2 alkenyl groups in one molecule, R 1 3SiO 1 / 2 unit (wherein R 1 is a halogen-substituted or non-substituted monovalent hydrocarbon group.), and SiO 4 / 2 unit, and is composed of SiO 4 / 2R relative to the unit 1 3SiO 1 / 2 0.01 to 1 part by mass, more preferably 0.05 to 0.8 part by mass, based on 100 parts by mass in total of the organopolysiloxane resin (B) in which the molar ratio of the unit is 0.5 or more and 1.5 or less.

[0018] <Solvent> As described above, when the viscosity of the silicone-based pressure-sensitive adhesive composition of the present application is high, a solvent can be added for dilution. The solvent that can be used is a solvent in which the silicone component is compatible, and specifically, toluene, xylene, n-hexane, methylcyclohexane, cyclohexanone, isoparaffin, etc. can be mentioned. More preferably, it is toluene. The dilution ratio depends on the final viscosity, but it is preferably diluted so that the components (A) to (D) are 30 to 90% by mass, more preferably 40 to 80% by mass.

[0019] <Silane coupling agent> The silicone-based pressure-sensitive adhesive composition of the present application can be added with a silane coupling agent as needed. As the silane coupling agent (G), vinyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, etc. can be used. The addition amount is based on 100 parts by mass in total of the organopolysiloxane (A) having at least 2 alkenyl groups in one molecule, R 1 3SiO 1 / 2 unit (wherein R 1 is a halogen-substituted or unsubstituted monovalent hydrocarbon group.), and SiO 4 / 2 unit, and is composed of SiO 4 / 2 unit to R 1 3SiO 1 / 2 0 to 5 parts by mass, more preferably 0 to 3 parts by mass, based on 100 parts by mass in total of the organopolysiloxane resin (B) in which the molar ratio of the unit is 0.5 or more and 1.5 or less.

[0020] The silicone-based pressure-sensitive adhesive composition of the present application can be added with a filler, an antioxidant, etc. within a range that satisfies the properties.

[0021] Various components are weighed into a reaction vessel and stirred with a motor equipped with a stirring spring or the like, whereby it can be easily produced.

Example

[0022] Next, the silicone-based pressure-sensitive adhesive composition of the present application and the pressure-sensitive adhesive tape using the same will be described in detail by way of Examples and Comparative Examples.

[0023] <Method for Measuring Mass Average Molecular Weight (Mw)> The molecular weight of the silicone resin was measured by gel permeation chromatography (GPC) at 40 °C in a THF mobile phase of 0.6 mL / min using two columns connected in series, namely, a column manufactured by Waters and named HSPgel HR4.0 and a column manufactured by Waters and named HSPgel MB-M. A polystyrene standard was used for linear regression calibration. In the GPC measurement using polystyrene standard calibration, a refractive index detector was used.

[0024] <Preparation of Liquid for Example 1> Vi1Me2SiO 1 / 2 Unit, Me2SiO 2 / 2 Unit (Vi represents a vinyl group and Me represents a methyl group), 40 g of an oily polysiloxane (A) having a viscosity of 65,000 mPa·s at 25 °C, Me3SiO 1 / 2 Unit, SiO 1 / 4 Unit consisting of, SiO 4 / 2 R with respect to the SiO 1 3SiO 1 / 2 60 g of an organosiloxane resin (B) in which the molar ratio of the unit is 0.75, 0.51 g of (C1) represented by Formula 3 having a mass average molecular weight of 354.65 and having three silicon atom-bonded hydrogen atoms in one molecule represented by Formula (3), a toluene solution (D) of a platinum-vinyl group-containing siloxane complex such that the platinum amount is 100 ppm with respect to the total of components (A) to (C), and toluene were weighed so that the components (A) to (D) became 60%, and stirred until uniform.

[0025] <Preparation of Liquids for Examples 2 to 4 and Comparative Examples 1 to 6> Weighed various materials in the amounts shown in Table 1 and Table 2, and prepared the liquids of Examples 2 to 4 and Comparative Examples 1 to 6 in the same procedure as the liquid preparation of Example 1. Incidentally, (C2) is a compound represented by the formula (4) with a mass average molecular weight of 330.67, (C3) is a compound represented by the formula (5) with a mass average molecular weight of 374.71, (C4) is a compound represented by the formula (6) with a mass average molecular weight of 474.83, (C5) is a compound represented by the formula (7) with a mass average molecular weight of 240.51, and (C6) is a compound represented by the formula (8) with a mass average molecular weight of 468.80. (C7) is Me3SiO 1 / 2 unit, MeHSiO 2 / 2 unit, Me2SiO 2 / 2 unit, and is an oily organohydrogenpolysiloxane having a viscosity of about 30 mPa·s at 25°C and 0.7 mol of Si-H groups in 100 g, with a mass average molecular weight of 15,000. (C8) is Me2HSiO 1 / 2 unit, Me2SiO 2 / 2 unit, and is an oily organohydrogenpolysiloxane having a viscosity of about 20 mPa·s at 25°C and 0.1 mol of Si-H groups in 100 g, with a mass average molecular weight of 10,000. JPEG0007698567000003.jpg4738 Formula 3 JPEG0007698567000004.jpg4644 Formula 4 JPEG0007698567000005.jpg4734 Formula 5 JPEG0007698567000006.jpg4732 Formula 6 JPEG0007698567000007.jpg4543 Formula 7 JPEG0007698567000008.jpg4828 Formula 8

[0026] <180° peel test> A silicone-based pressure-sensitive adhesive composition solution was applied onto a polyethylene terephthalate (PET) film with a thickness of 50 μm using an applicator so that the cured thickness would be 40 μm, and then cured by heating at 130 °C for 3 minutes to produce a pressure-sensitive adhesive film. The film was cut into a width of 25 mm to form a tape shape. This pressure-sensitive adhesive tape was attached to a nylon base fabric coated with silicone, and crimped by reciprocating a roller covered with a rubber layer weighing 2 kg twice. After leaving it at room temperature for about 20 hours, the force (N / 25 mm) required to peel the tape from the nylon base fabric at an angle of 180° at a speed of 300 mm / min was measured using a tensile tester. It is the average of n = 10. A peel strength of 0.5 N / 25 mm or more was considered qualified, and less than 0.5 N / 25 mm was considered unqualified. The results are shown in Table 3 and Table 4. Note that Comparative Example 2 did not cure, so it is represented by (-).

[0027] <Glass paste residue test> In the paste residue test using a nylon base fabric coated with silicone, since the migration of the silicone composition was difficult to confirm, a test using glass was conducted to improve visibility. In the same manner as the 180° peel test, a 25-mm-wide pressure-sensitive adhesive tape was produced and clamped to the glass by reciprocating a 2-kg roller twice. When the film was pulled at a speed of about 300 mm / min, it was visually confirmed whether the components of the silicone composition migrated to the glass surface. Those without migration were considered qualified (:〇), and those with migration were considered unqualified (:×). The results are shown in Table 3 and Table 4. Note that Comparative Example 2 did not cure, so it is represented by (-).

[0028] 30 to 70 parts by mass of an organopolysiloxane (A) having at least 2 alkenyl groups in one molecule, R 1 3SiO 1 / 2 units (wherein R 1 is a halogen-substituted or unsubstituted monovalent hydrocarbon group), and SiO 4 / 2 units, and the R 4 / 2 to SiO 1 3SiO1 / 2 The silicone-based pressure-sensitive adhesive composition containing 70 to 30 parts by mass of an organopolysiloxane resin (B) with a unit molar ratio of 0.5 or more and 1.5 or less, a silicone compound (C) having 3 silicon atom-bonded hydrogen atoms in one molecule and a mass average molecular weight of 1,000 or less, where the silicon atom-bonded hydrogen atoms are 0.5 to 20 moles with respect to a total of 1 mole of alkenyl groups of the component (A), and a platinum-based catalyst (D) in an amount of 0.1 to 1000 ppm by mass as platinum amount with respect to the total of (A), (B), and (C), passed both the 180° peel test and the glass paste residue test.

[0029] [Table 1]

[0030] [Table 2]

[0031] [Table 3]

[0032] [Table 4]

Claims

1. 30 to 70 parts by mass of an organopolysiloxane (A) having at least 2 alkenyl groups in one molecule, R １ ３ SiO １ / ２ unit (wherein R １ is a halogen-substituted or unsubstituted monovalent hydrocarbon group).) and SiO ４ / ２ units, and the organopolysiloxane resin (B) composed of SiO ４ / ２ units, with a molar ratio of R １ ３ SiO １ / ２ units being 0.5 or more and 1.5 or less, is 70 to 30 parts by mass, and the total of (A) and (B) is 100 parts by mass, a silicone compound (C) having 3 silicon atom-bonded hydrogen atoms in one molecule represented by the following formula (1) or the following formula (2) and having a mass average molecular weight of 1,000 or less, wherein the silicon atom-bonded hydrogen atoms are 0.5 to 20 moles per 1 mole of the total alkenyl groups of the component (A), a platinum-based catalyst (D) in an amount of 0.1 to 1000 ppm by mass as the platinum amount based on the total of (A), (B), and (C), A silicone-based pressure-sensitive adhesive composition containing the same. Formula (1) R １ is an organic group including a monovalent hydrocarbon group having 1 to 10 carbon atoms which is unsubstituted or substituted Formula (2) R ２ is an organic group including a monovalent hydrocarbon group having 1 to 10 carbon atoms which is unsubstituted or substituted As the addition amount, the silicon atom-bonded hydrogen atoms are 0.5 to 20 moles, more preferably 1 to 15 moles, per 1 mole of the total alkenyl groups of the organopolysiloxane (A).

2. The silicone-based pressure-sensitive adhesive composition according to Claim 1, wherein the formula (1) or the formula (2) is represented by the following formula (3) to formula (6). Formula 3 Formula 4 Formula 5 Formula 6

3. An organopolysiloxane (A) having at least two alkenyl groups in one molecule, R １ ３ SiO １ / ２ units (wherein R １ is a halogen-substituted or unsubstituted monovalent hydrocarbon group.), and SiO ４ / ２ units, and the silicone-based pressure-sensitive adhesive composition according to claim 1 or claim 2, wherein 0.01 to 1 part by mass of acetylene alcohols is added as a reaction regulator with respect to a total of 100 parts by mass of an organopolysiloxane resin (B) in which the molar ratio of the R ４ / ２ １ ３ SiO １ / ２ units is 0.5 or more and 1.5 or less.​

4. A pressure-sensitive adhesive tape produced using the silicone-based pressure-sensitive adhesive composition according to any one of Claims 1 to 3.

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