Heat-curable perfluoropolyether adhesive composition, adhesive and adhesive tape using the cured product

Abstract

The present invention pertains to a curable perfluoropolyether adhesive composition that contains: (A) 100 parts by mass of a straight-chain perfluoropolyether compound that has at least two alkenyl groups in one molecule, and that has, in the main chain, a perfluoropolyether structure including a repeating unit represented by —CaF2aO— (where a is an integer from 1-6); (B) in an amount effective for curing, a fluorine-containing organohydrogenpolysiloxane having, in one molecule, at least two hydrogen atoms to which a silicon atom is bonded; and (C) a catalyzing quantity of a hydrosilylation reaction catalyst. The composition does not contain an organic solvent. This configuration makes it possible to provide: a curable perfluoropolyether adhesive composition with which can be achieved a cured product that has excellent heat resistance, weather resistance, water repellency, oil repellency, chemical resistance, solvent resistance, etc., and that is characterized in particular in that voids are not generated on the surface of a coating film in a heating step; and an adhesive and adhesive tape that include said cured product.

Description

[Technical Field]

[0001] The present invention relates to a curable perfluoropolyether pressure-sensitive adhesive composition (hereinafter also referred to as "perfluoropolyether pressure-sensitive adhesive composition") that forms a pressure-sensitive adhesive (cured perfluoropolyether rubber or cured perfluoropolyether gel) that has excellent heat resistance, oil resistance, chemical resistance, solvent resistance, low-temperature properties, moisture resistance, low gas permeability, etc., and that forms a smooth coating film with no voids on the film surface after curing, and to a pressure-sensitive adhesive and pressure-sensitive adhesive tape using the cured product thereof. [Background technology]

[0002] It has been proposed that a cured product having excellent and well-balanced properties such as heat resistance, chemical resistance, solvent resistance, water repellency, oil repellency, and weather resistance can be obtained from a composition comprising a linear perfluoropolyether compound having at least two alkenyl groups in one molecule and a perfluoropolyether structure in the main chain, an organosilicon compound such as a fluorine-containing organohydrogenpolysiloxane having two or more H-SiOSiO structures in one molecule, and a hydrosilylation reaction catalyst (Patent Documents 1 and 2).

[0003] Meanwhile, adhesives are used in a variety of applications, primarily in labels and adhesive tapes attached to products. Recently, advances in electronic device-related technology have led to a wide range of applications, including adhesive films for display protection and protective films used during the manufacturing process. Furthermore, in addition to surface protection, adhesives are also used in optical components, taking advantage of the transparency of the material, and are being used in applications within products, such as Optical Clear Adhesive Tape (OCA tape).

[0004] The main classifications of adhesives are acrylic, rubber, and silicone, each with its own advantages and disadvantages. Silicone adhesives are less costly than acrylic or rubber adhesives, but are superior to the other two types in terms of heat resistance, cold resistance, weather resistance, chemical resistance, and electrical insulation.

[0005] Recently, mobile phones and other devices have become widely used, and most of the adhesive films used to protect their displays use silicone adhesives. Silicone has good wettability to adherends, so it does not trap air bubbles when applied, and it does not shift or peel off on its own. It also has good reworkability, so it can be reapplied (Patent Document 3). The same is true for protective films used during product manufacturing processes, which also require heat resistance, so adhesive films using silicone adhesives are used in large quantities.

[0006] Furthermore, among mobile phones, smartphones, which have more advanced functions than conventional devices, are rapidly becoming popular, and many of them can be operated by touching a display called a touch panel instead of the conventional buttons. A similar device is a tablet device, which is a portable computer equipped with a touch panel. As the popularity of these devices increases, the display area also increases, and the demand for adhesive film for screen protection is on the rise.

[0007] However, although such silicone pressure-sensitive adhesives have sufficient performance for most applications, there has been a strong demand for pressure-sensitive adhesive compositions with excellent chemical and solvent resistance, such as for applications requiring even greater chemical and solvent resistance, such as those used around automobile engines and barcode labels used in clinical and pathological testing processes.

[0008] Among these, a curable perfluoropolyether pressure-sensitive adhesive composition has been proposed (Patent Document 4). This composition has been shown to have excellent heat resistance, weather resistance, water repellency, oil repellency, etc., and to give a cured product with excellent chemical resistance and solvent resistance. However, the exemplified composition contains trace amounts of organic solvents such as ethanol and toluene, and when the coating film is heat-cured, the organic solvent gasifies in the film due to the low gas permeability of the fluorine material, causing voids to form and impairing the flatness of the coating surface. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Patent No. 2990646 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-248166 [Patent Document 3] Japanese Patent Application Publication No. 07-197008 [Patent Document 4] Japanese Patent Application Publication No. 2019-38904 Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention has been made in view of the above circumstances, and aims to provide a curable perfluoropolyether pressure-sensitive adhesive composition which gives a cured product that has excellent heat resistance, weather resistance, water repellency, oil repellency, chemical resistance, solvent resistance, etc., and is characterized in that no voids are generated on the coating surface during heating, in particular, and an adhesive and pressure-sensitive adhesive tape containing the cured product. [Means for solving the problem]

[0011] In order to solve the above problems, a first aspect of the present invention provides a curable perfluoropolyether pressure-sensitive adhesive composition, comprising: (A) A compound having at least two alkenyl groups in one molecule and having -C in the main chain a F 2a 100 parts by mass of a linear perfluoropolyether compound having a perfluoropolyether structure containing a repeating unit represented by the formula: O- (wherein a represents an integer of 1 to 6). (B) a fluorine-containing organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms per molecule: a curing effective amount (C) Hydrosilylation reaction catalyst: catalytic amount The present invention provides a curable perfluoropolyether pressure-sensitive adhesive composition containing the above compound, wherein the composition does not contain any organic solvent.

[0012] A curable perfluoropolyether pressure-sensitive adhesive composition containing components (A) to (C) as in the first aspect of the present invention and containing no organic solvent in the composition is a curable perfluoropolyether pressure-sensitive adhesive composition that not only has excellent heat resistance, weather resistance, water repellency, oil repellency, oil resistance, low temperature properties, moisture resistance, low gas permeability, etc., but also gives a cured product (pressure-sensitive adhesive) that, after curing, has a smooth coating film free of voids on the film surface. Furthermore, a curable perfluoropolyether pressure-sensitive adhesive composition of the present invention containing components (A) to (C) as described above and containing no organic solvent in the composition can give a rubber cured product (perfluoropolyether rubber cured product).

[0013] In addition, in a first aspect of the present invention, there is provided a curable perfluoropolyether pressure-sensitive adhesive composition further comprising (E) an organic solvent-free addition reaction inhibitor in an amount of 0.01 to 5 parts by mass per 100 parts by mass of component (A).

[0014] The curable perfluoropolyether pressure-sensitive adhesive composition of the present invention, which contains component (E) and does not contain any organic solvent, does not thicken or gel during preparation of the composition or application to a substrate, improving workability, and is a curable perfluoropolyether pressure-sensitive adhesive composition that is excellent in heat resistance, weather resistance, water repellency, oil repellency, oil resistance, low temperature properties, moisture resistance, low gas permeability, etc., and in particular gives a cured product (pressure-sensitive adhesive) that, after curing, forms a smooth coating film without voids on the film surface.

[0015] In a first aspect of the present invention, there is provided a curable perfluoropolyether pressure-sensitive adhesive composition further comprising, as component (F), 0.5 to 20 parts by mass of hydrophobic silica powder per 100 parts by mass of component (A). The hydrophobic silica powder of component (F) is essentially free of organic solvents.

[0016] A pressure-sensitive adhesive composition containing such hydrophobic silica powder becomes a curable perfluoropolyether pressure-sensitive adhesive composition with excellent scratch resistance.

[0017] In a second aspect of the present invention, there is provided a curable perfluoropolyether pressure-sensitive adhesive composition, (A) A compound having at least two alkenyl groups in one molecule and having -C in the main chain a F 2a A linear perfluoropolyether compound having a perfluoropolyether structure containing a repeating unit represented by the formula: O- (wherein a represents an integer of 1 to 6): 100 to 40 parts by mass (D) Polyfluoromonoalkenyl compound having one alkenyl group per molecule and having a perfluoropolyether structure in the main chain: 0 to 60 parts by mass (provided that the total amount of the components (A) and (D) is 100 parts by mass). (B) a fluorine-containing organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms per molecule: a curing effective amount (C) Hydrosilylation reaction catalyst: catalytic amount The present invention provides a curable perfluoropolyether pressure-sensitive adhesive composition containing the above compound, wherein the composition does not contain any organic solvent.

[0018] In addition, in a second aspect of the present invention, there is provided a curable perfluoropolyether pressure-sensitive adhesive composition containing 99.9 to 40 parts by mass of the component (A) and 0.1 to 60 parts by mass of the component (D) (provided that the total amount of the component (A) and the component (D) is 100 parts by mass).

[0019] A curable perfluoropolyether pressure-sensitive adhesive composition containing components (A) to (D) as in the second aspect of the present invention and containing no organic solvents in the composition can provide a cured product (pressure-sensitive adhesive) that is excellent in heat resistance, weather resistance, water repellency, oil repellency, oil resistance, low-temperature properties, moisture resistance, low gas permeability, etc., and in particular, provides a void-free, smooth coating film on the surface after curing. Furthermore, a curable perfluoropolyether pressure-sensitive adhesive composition containing components (A) to (D) as described above and containing no organic solvents in the composition can provide a rubber cured product or a gel cured product (a perfluoropolyether rubber cured product or a gel cured product).

[0020] In the present invention, a perfluoropolyether gel cured product (hereinafter sometimes referred to as perfluoropolyether gel) refers to a cured product with a low crosslink density that contains perfluoropolyether as the main component and has a penetration (also referred to as cone penetration) of 10 to 100 as defined in JIS K6249 according to the consistency test method (1 / 4 cone) of JIS K2220. This corresponds to a product that has such low hardness (i.e., softness) and low elasticity (low stress) that it does not exhibit a valid rubber hardness value, with a measured value (rubber hardness value) of 0 in a rubber hardness measurement according to JIS K6301, and in this respect is different from so-called perfluoropolyether rubber cured products (rubber-like elastomers).

[0021] It should be noted that a cured coating of a perfluoropolyether gel cured product having a softness of 10 to 100 in penetration according to JIS K6249 using JIS K2220 (1 / 4 cone) as described above generally corresponds to a soft coating of "6B" or less in a pencil hardness test (a scratch resistance test using a pencil lead at a 45° angle in accordance with JIS K5600-5-4), whereas a cured coating of a perfluoropolyether rubber cured product (rubber elastomer) generally exhibits a scratch resistance of "5B" or more in the same test.

[0022] In a second embodiment of the present invention, the component (D) is represented by the following general formula (2): Rf 1 -(X') p -CH=CH2(2) wherein X' is -CH2-, -OCH2-, -CH2OCH2-, or -CO-NR 2 -Y'- (wherein Y' is -CH2- or a group represented by the following structural formula (Z') (i.e., a dimethylphenylsilylene group represented at the ortho, meta, or para position), [ka] R 2 is a hydrogen atom, a methyl group, a phenyl group, or an allyl group.) and p is 0 or 1. Rf1 has the general formula F-[CF(CF3)CF2O] w It is a perfluoropolyether structure represented by -CF(CF3)- (wherein w represents an integer of 1 to 500).] is preferred.

[0023] A composition containing such component (D) is a curable perfluoropolyether pressure-sensitive adhesive composition that gives a cured product (pressure-sensitive adhesive) with better chemical resistance and solvent resistance.

[0024] In addition, in a second aspect of the present invention, there is provided a curable perfluoropolyether pressure-sensitive adhesive composition further comprising (E) an organic solvent-free addition reaction inhibitor in an amount of 0.01 to 5 parts by mass per 100 parts by mass of the total of the components (A) and (D).

[0025] The curable perfluoropolyether pressure-sensitive adhesive composition of the present invention, which contains component (E) and does not contain any organic solvent, does not thicken or gel during preparation of the composition or application to a substrate, improving workability, and is a curable perfluoropolyether pressure-sensitive adhesive composition that is excellent in heat resistance, weather resistance, water repellency, oil repellency, oil resistance, low temperature properties, moisture resistance, low gas permeability, etc., and in particular gives a cured product (pressure-sensitive adhesive) that, after curing, forms a smooth coating film without voids on the film surface.

[0026] In a second aspect of the present invention, there is provided a curable perfluoropolyether pressure-sensitive adhesive composition further comprising, as component (F), 0.5 to 20 parts by mass of hydrophobic silica powder, per 100 parts by mass of the total of components (A) and (D). The hydrophobic silica powder of component (F) is essentially free of organic solvents.

[0027] A pressure-sensitive adhesive composition containing such hydrophobic silica powder becomes a curable perfluoropolyether pressure-sensitive adhesive composition with excellent scratch resistance.

[0028] In the first or second embodiment of the present invention, the component (C) does not contain an organic solvent.

[0029] Component (C) is used in this manner so that the composition does not contain any organic solvent.

[0030] In the first or second aspect of the present invention, the component (A) is represented by the following general formula (1): [ka] wherein X is —CH—, —CHO—, —CHOCH—, or —Y—NR 1 -CO- (wherein Y is -CH2- or a group represented by the following structural formula (Z) (i.e., a dimethylphenylsilylene group represented in the ortho, meta, or para position), R 1 is a hydrogen atom, a methyl group, a phenyl group, or an allyl group. X' is -CH2-, -OCH2-, -CH2OCH2-, or -CO-NR 2 -Y'- (wherein Y' is -CH2- or a group represented by the following structural formula (Z') (i.e., a dimethylphenylsilylene group represented in the ortho, meta, or para position), R 2 is a hydrogen atom, a methyl group, a phenyl group, or an allyl group. p is independently 0 or 1, r is an integer of 2 to 6, m and n are each an integer of 0 to 600, and the sum of m and n is 50 to 600. [ka] [ka] ] It is preferable that the compound is a linear perfluoropolyether compound represented by the following formula:

[0031] A composition containing such component (A) can provide a cured product (adhesive) that has superior chemical resistance and solvent resistance, and also provides a curable perfluoropolyether adhesive composition with high adhesive strength.

[0032] In the first or second aspect of the present invention, the composition is preferably a curable perfluoropolyether pressure-sensitive adhesive composition that cures to form a pressure-sensitive adhesive having an adhesive strength of 0.001 N / 25 mm to 10.0 N / 25 mm.

[0033] A composition that gives a cured product having such adhesive strength will be a curable perfluoropolyether adhesive composition that has good adhesive strength to the adherend.

[0034] In the first or second aspect of the present invention, the cured product of the curable perfluoropolyether pressure-sensitive adhesive composition has a volume resistivity of 1×10 9 It is preferable to use a non-conductive adhesive with a resistance of Ω·cm or more.

[0035] The curable perfluoropolyether pressure-sensitive adhesive composition of the present invention can be suitably used as a material for such non-conductive pressure-sensitive adhesives.

[0036] The present invention also provides a pressure-sensitive adhesive comprising a cured product of the curable perfluoropolyether pressure-sensitive adhesive composition.

[0037] Thus, the curable perfluoropolyether pressure-sensitive adhesive composition of the present invention can be used as a pressure-sensitive adhesive that provides a cured perfluoropolyether rubber or perfluoropolyether gel that has excellent adhesion to various substrates.

[0038] The present invention also provides a pressure-sensitive adhesive tape comprising a substrate and a cured layer of the curable perfluoropolyether pressure-sensitive adhesive composition laminated thereon.

[0039] In this way, by laminating a cured layer of the curable perfluoropolyether pressure-sensitive adhesive composition of the present invention (a pressure-sensitive adhesive layer consisting of a cured perfluoropolyether rubber or a cured perfluoropolyether gel) on a substrate, it can be used as a pressure-sensitive adhesive tape having a non-conductive pressure-sensitive adhesive layer. [Effects of the Invention]

[0040] As described above, the perfluoropolyether pressure-sensitive adhesive composition of the present invention can give a rubbery or gel-like cured product (pressure-sensitive adhesive) that has excellent heat resistance, weather resistance, oil resistance, low-temperature properties, moisture resistance, low gas permeability, water repellency, oil repellency, chemical resistance, solvent resistance, etc., and in particular, forms a smooth coating film without voids on the film surface after curing. DETAILED DESCRIPTION OF THE INVENTION

[0041] As described above, there has been a need for the development of a curable perfluoropolyether pressure-sensitive adhesive composition that not only has excellent heat resistance, weather resistance, water repellency, oil repellency, etc., but also gives a cured product (pressure-sensitive adhesive) that forms a smooth coating film, particularly one that is free of voids on the film surface after curing, as well as a pressure-sensitive adhesive and pressure-sensitive adhesive tape containing the cured product.

[0042] As a result of extensive research conducted by the present inventors to achieve the above-mentioned object, they discovered that the specific perfluoropolyether pressure-sensitive adhesive composition of the present invention can give a rubbery or gel-like cured product (cured perfluoropolyether rubber or cured perfluoropolyether gel) that has superior chemical resistance and solvent resistance compared to conventional silicone pressure-sensitive adhesives, and in particular can give a composition that gives a cured product (pressure-sensitive adhesive) that, after curing, forms a smooth coating film without voids on the film surface, leading to the present invention.

[0043] <First Aspect> That is, a first aspect of the present invention is a curable perfluoropolyether pressure-sensitive adhesive composition that gives a rubber-like cured product (cured perfluoropolyether rubber product), comprising: (A) A compound having at least two alkenyl groups in one molecule and having -C in the main chain a F 2a 100 parts by mass of a linear perfluoropolyether compound having a perfluoropolyether structure containing a repeating unit represented by the formula: O- (wherein a represents an integer of 1 to 6). (B) a fluorine-containing organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms per molecule: a curing effective amount (C) Hydrosilylation reaction catalyst: catalytic amount and wherein the composition does not contain any organic solvent.

[0044] The first embodiment of the present invention will be described in detail below, but the present invention is not limited thereto.

[0045] [Component (A)] In a first aspect of the present invention, component (A) contained in the curable perfluoropolyether pressure-sensitive adhesive composition of the present invention acts as the main component (base polymer) of the curable perfluoropolyether pressure-sensitive adhesive composition of the present invention, and is a linear perfluoropolyether compound having at least two alkenyl groups in one molecule and a perfluoropolyether structure (perfluorooxyalkylene structure) in the main chain, preferably a divalent perfluorooxyalkylene structure.

[0046] Here, the perfluorooxyalkylene structure is -C a F 2a It contains a large number of repeating oxyalkylene units represented by the formula: O- (wherein a in each unit is independently an integer of 1 to 6), and examples thereof include those represented by the following general formula (3). (C a F 2a O) q (3) (In the formula, q is an integer of 50 to 600, preferably an integer of 50 to 400, and more preferably an integer of 50 to 200.)

[0047] Each repeating unit -C constituting the perfluorooxyalkylene structure represented by the above formula (3) a F 2a Examples of O- (that is, oxyalkylene unit) include the following structures: The perfluoroalkyl ether structure may be composed of one type of these repeating structures alone, or may be a combination of two or more types.

[0048] -CF2O- -CF2CF2O- -CF2CF2CF2O- -CF(CF3)CF2O- -CF2CF2CF2CF2O- -CF2CF2CF2CF2CF2CF2O- -C(CF3)2O-

[0049] Among these, the following structure is particularly preferred: -CF2O- -CF2CF2O- -CF2CF2CF2O- -CF(CF3)CF2O-

[0050] In the present invention, the term "linear" refers to the individual repeating units -C constituting the perfluoropolyether structure (perfluorooxyalkylene structure) of the main chain. a F 2a This means that O- (oxyalkylene units) are bonded together in a linear chain, and each repeating unit (oxyalkylene unit) itself may be a linear oxyalkylene unit or a branched oxyalkylene unit (for example, -CF(CF3)CF2O-, -C(CF3)2O-, etc.).

[0051] The alkenyl group in the linear perfluoropolyether compound of component (A) preferably has 2 to 8 carbon atoms, particularly 2 to 6 carbon atoms, and has a CH2=CH- structure at its terminal, such as a vinyl group, allyl group, propenyl group, isopropenyl group, butenyl group, or hexenyl group, and is particularly preferably a vinyl group or allyl group. The alkenyl group may be directly bonded to both ends of the perfluoropolyether structure, particularly a divalent perfluorooxyalkylene structure, that constitutes the main chain of the linear perfluoropolyether compound, or may be bonded to a divalent linking group, such as -CH2-, -CHO-, -CHOCH2-, or -Y-NR-CO- (wherein Y is -CH2- or a group represented by the following structural formula (Z) [ka] (Dimethylphenylsilylene group shown in the ortho, meta, or para position) and R is a hydrogen atom, a methyl group, a phenyl group, or an allyl group.] In addition, component (A) has at least two alkenyl groups per molecule.

[0052] Examples of the component (A) include polyfluorodialkenyl compounds represented by the following general formula (4) or (5). CH2=CH-(X) p -Rf 2 -(X') p -CH=CH2(4) CH2=CH-(X) p -Q-Rf 2 -Q-(X') p -CH=CH2(5) wherein X is independently —CH—, —CHO—, —CHOCH—, or —Y—NR 1 -CO- (wherein Y is -CH2- or a group represented by the following structural formula (Z) and R 1 is a hydrogen atom, a methyl group, a phenyl group, or an allyl group; and X' is -CH2-, -OCH2-, -CH2OCH2-, or -CO-NR 2 -Y'- (wherein Y' is -CH2- or a group represented by the following structural formula (Z'), R 2 is a hydrogen atom, a methyl group, a phenyl group, or an allyl group. [ka] (Dimethylphenylsilylene group shown in the ortho, meta, or para position) [ka] (Dimethylphenylsilylene group shown in the ortho, meta, or para position) Rf 2 is a divalent perfluoropolyether structure (perfluorooxyalkylene structure), and is represented by the above formula (3), that is, (C a F 2a O) qQ is a divalent hydrocarbon group having 1 to 15 carbon atoms, which may contain an ether bond, and specifically an alkylene group or an alkylene group which may contain an ether bond. p is independently 0 or 1.]

[0053] As such a linear perfluoropolyether compound of component (A), one represented by the following general formula (1) is particularly suitable. [ka] [In the formula, X, X', and p are the same as above, r is an integer of 2 to 6, m and n are each an integer of 0 to 600, and the sum of m and n is 50 to 600.]

[0054] The linear perfluoropolyether compound of the general formula (1) preferably has a polyethylene-equivalent weight-average molecular weight of 3,000 to 100,000, particularly 4,000 to 50,000, as measured by gel permeation chromatography (GPC) analysis using a fluorinated solvent as the developing solvent to determine molecular weight distribution. A weight-average molecular weight of 3,000 or more results in reduced swelling in gasoline and various solvents. In particular, swelling in gasoline is 6% or less, satisfying the properties required for components requiring gasoline resistance. Furthermore, a weight-average molecular weight of 100,000 or less provides practical application because the viscosity is not too high and workability is excellent. The degree of polymerization (m+n) of the linear perfluoropolyether compound of the general formula (1) can also be determined as a polyethylene-equivalent number-average polymerization degree or weight-average polymerization degree, as measured by gel permeation chromatography (GPC) analysis using a fluorinated solvent as the developing solvent to determine molecular weight distribution. These number-average polymerization degrees and number-average molecular weights are 19 It can also be calculated from the ratio of the terminal structure to the repeating unit structure obtained from the F-NMR spectrum.

[0055] Specific examples of the linear perfluoropolyether compound represented by general formula (1) include those represented by the following formulas.

[0056] [ka]

[0057] [ka]

[0058] [ka] (In the formula, m and n each represent an integer of 0 to 600, preferably an integer of 0 to 200, and an integer that satisfies m+n=50 to 600, preferably m+n=50 to 200.)

[0059] Furthermore, in the present invention, in order to adjust the linear perfluoropolyether compound of the above formula (1) to a desired weight average molecular weight depending on the purpose, it is also possible to use the chain-extended product as component (A) by subjecting the linear perfluoropolyether compound described above to a hydrosilylation reaction with an organosilicon compound containing two SiH groups in the molecule in a conventional manner and under conventional conditions. The linear perfluoropolyether compound of component (A) may be used alone or in combination of two or more.

[0060] [(B) Component] In a first embodiment of the present invention, component (B) acts as a crosslinking agent and / or chain extender for component (A). Component (B) is a fluorine-containing organohydrogenpolysiloxane having at least two, and preferably three or more, silicon-bonded hydrogen atoms (hydrosilyl groups represented by SiH) per molecule. Examples of component (B) include, but are not limited to, known fluorine-containing organohydrogenpolysiloxanes described in Patent Documents 1, 2, and 4.

[0061] The fluorine-containing organohydrogenpolysiloxane of component (B) does not contain adhesive functional groups having heteroatoms such as nitrogen, oxygen, or sulfur in the molecule (e.g., alkoxy groups, epoxy groups, (meth)acryloxy groups, mercapto groups, etc.), and is therefore clearly distinguishable from the organosilicon compounds of optional component (G) described below (particularly organohydrogenpolysiloxanes having such adhesive functional groups). Substituted or unsubstituted amide groups, ether bonds (—O—), carbonyl groups (—(C═O)—), and ester groups (—(C═O)O—) are not included in the adhesive functional groups having heteroatoms.

[0062] From the viewpoints of compatibility with component (A) or, in the second embodiment of the present invention described below, component (A) and component (D) described below, dispersibility, uniformity of the rubber or gel cured product (adhesive) after curing, and the like, the fluorine-containing organohydrogenpolysiloxane of component (B) that has one or more monovalent perfluoroalkyl groups, monovalent perfluorooxyalkyl groups, divalent perfluoroalkylene groups and / or divalent perfluorooxyalkylene groups per molecule can be suitably used.

[0063] Examples of the monovalent or divalent fluorine-containing organic group include perfluoroalkyl groups, perfluorooxyalkyl groups, perfluoroalkylene groups and perfluorooxyalkylene groups represented by the following formulae.

[0064] C g F 2g+1 - -C g F 2g - (In the formula, g is an integer of 1 to 20, preferably an integer of 2 to 10.)

[0065] [ka] (In the formula, f is an integer of 1 to 200, preferably an integer of 1 to 100, and h is an integer of 1 to 3.)

[0066] [ka] (In the formula, i and j are each an integer of 1 or more, preferably an integer of 1 to 100, and the average of i+j is 2 to 200, preferably 2 to 100.)

[0067] -(CF2O) d -(CF2CF2O) e -CF2- (In the formula, d and e are each an integer of 1 to 50, preferably an integer of 1 to 40.)

[0068] Furthermore, it is preferable that these perfluoroalkyl groups, perfluorooxyalkyl groups, perfluoroalkylene groups, or perfluorooxyalkylene groups are linked to the silicon atom by a divalent linking group, and the divalent linking group may be an alkylene group, an arylene group, or a combination thereof, or one in which an ether-bonded oxygen atom, an amide bond, a carbonyl bond, an ester bond, a diorganosilylene group, or the like is interposed in these groups, and examples thereof include, but are not limited to, the following divalent linking groups having 2 to 12 carbon atoms:

[0069] -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2OCH2-, -CH2CH2CH2-NH-CO-, -CH2CH2CH2-N(Ph)-CO-, -CH2CH2CH2-N(CH3)-CO-, -CH2CH2CH2-N(CH2CH3)-CO-, -CH2CH2-Si(CH3)2-Ph'-N(CH3)-CO-, -CH2CH2CH2-Si(CH3)2-Ph'-N(CH3)-CO-, -CH2CH2CH2-O-CO- (In the formula, Ph is a phenyl group, and Ph' is a phenylene group.)

[0070] Furthermore, in the fluorine-containing organohydrogenpolysiloxane of component (B), examples of the monovalent substituent bonded to silicon atoms other than the monovalent or divalent fluorine-containing organic groups and silicon-bonded hydrogen atoms (SiH groups) include alkyl groups such as methyl groups, ethyl groups, propyl groups, butyl groups, hexyl groups, cyclohexyl groups, octyl groups, and decyl groups; alkenyl groups such as vinyl groups and allyl groups; aryl groups such as phenyl groups, tolyl groups, and naphthyl groups; aralkyl groups such as benzyl groups and phenylethyl groups; and unsubstituted or substituted monovalent hydrocarbon groups having 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms, in which some or all of the hydrogen atoms of these groups have been substituted with chlorine atoms, cyano groups, or the like, such as chloromethyl groups, chloropropyl groups, and cyanoethyl groups.

[0071] The fluorine-containing organohydrogenpolysiloxane of component (B) may have a siloxane skeleton in the molecule that is cyclic, linear, branched, or three-dimensionally networked, or a combination thereof. The number of silicon atoms in this fluorine-containing organohydrogenpolysiloxane is not particularly limited, but is usually about 2 to 60, and preferably about 3 to 30.

[0072] Examples of component (B) having such a monovalent or divalent fluorine-containing organic group and a silicon-bonded hydrogen atom include the following compounds. These compounds may be used alone or in combination of two or more. In the following formulae, Me represents a methyl group, and Ph represents a phenyl group.

[0073] [ka]

[0074] [ka]

[0075] [ka]

[0076]

change

[0077]

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[0078]

change

[0079]

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[0080]

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[0081]

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[0082]

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[0083]

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[0084]

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[0085]

change

[0086] The amount of component (B) is an effective amount for curing component (A) and component (D), described below, i.e., a curing-effective amount. In particular, the amount is such that the hydrosilyl (Si-H) groups in component (B) are preferably 0.2 to 4 moles, more preferably 0.5 to 3 moles, per mole of alkenyl groups in component (A) in the present composition, or, in the second embodiment of the present invention described below, per mole of the total alkenyl groups in components (A) and (D). An amount of 0.2 moles or more of hydrosilyl (Si-H) groups ensures a sufficient degree of crosslinking, ensuring reliable production of a cured product. Furthermore, an amount of 4 moles or less of hydrosilyl (Si-H) groups prevents foaming during curing.

[0087] The component (B) can be used alone or in combination of two or more.

[0088] [(C) component] In a first embodiment of the present invention, the hydrosilylation catalyst (addition reaction catalyst) of component (C) of the present invention promotes the addition reaction of the alkenyl groups in component (A) or, in the second embodiment of the present invention described below, the alkenyl groups in component (A) and component (D) described below with the hydrosilyl groups in component (B). This hydrosilylation catalyst is generally a compound of a noble metal (platinum group metal) and is expensive, so relatively readily available platinum or platinum compounds are often used.

[0089] Examples of platinum compounds include chloroplatinic acid, complexes of chloroplatinic acid with olefins such as ethylene, complexes with vinylsiloxane, and metallic platinum supported on silica, alumina, carbon, etc. As platinum group metal catalysts other than platinum compounds, rhodium, ruthenium, iridium, and palladium compounds are also known, such as RhCl(PPh3)3, RhCl(CO)(PPh3)2, and Ru3(CO). 12 , IrCl(CO)(PPh3)2, Pd(PPh3)4, etc. can be mentioned as examples.

[0090] The amount of the hydrosilylation catalyst may be a catalytic amount, but is typically preferably 0.1 to 500 ppm (calculated as the mass of platinum group metal) relative to the total mass of components (A), (B), and (D), and more preferably 0.1 to 100 ppm.The hydrosilylation catalyst of component (C) may be used singly or in combination of two or more different types.

[0091] The hydrosilylation reaction catalyst (addition reaction catalyst) of component (C) of the present invention does not contain an organic solvent (for example, the platinum group metal catalyst is not diluted, dissolved, or dispersed in an organic solvent).

[0092] [Other ingredients] In the first embodiment of the present invention (or the second embodiment described below), various compounding ingredients may be optionally added in addition to the above components (A) to (C).

[0093] [(E) component] In the first embodiment of the present invention (or the second embodiment described below), it is optional to incorporate, as necessary, an inhibitor for the hydrosilylation reaction catalyst (addition reaction inhibitor) as component (E), which does not contain an organic solvent.

[0094] Component (E) can be added before heat curing, for example, during preparation of the curable perfluoropolyether pressure-sensitive adhesive composition or during application of the pressure-sensitive adhesive composition to a substrate, to prevent thickening or gelation of the pressure-sensitive adhesive composition. Examples of component (E) include acetylene alcohols such as 1-ethynyl-1-hydroxycyclohexane, 3-methyl-1-butyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, 3-methyl-1-penten-3-ol, and phenylbutynol; 3-methyl-3-penten-1-yne; 3,5-dimethyl-3-hexen-1-yne; polymethylvinylsiloxane cyclic compounds; and organophosphorus compounds. The addition of these compounds can maintain appropriate curing reactivity and storage stability. Component (E) may be used alone or in combination of two or more.

[0095] The amount of component (E) blended is in the range of 0 to 5 parts by mass per 100 parts by mass of component (A), or in the second embodiment of the present invention described below, per 100 parts by mass of the combined total of components (A) and (D), described below. When blended, the range of 0.01 to 5 parts by mass is preferred, and the range of 0.02 to 4 parts by mass is more preferred. If the blended amount is 5 parts by mass or less, the curability of the resulting composition will not decrease.

[0096] [Component (F)] In the first embodiment of the present invention (or the second embodiment described below), it is optional to blend a hydrophobic silica powder as component (F) as needed. The hydrophobic silica powder of component (F) is essentially free of organic solvents. The hydrophobic silica powder of component (F) imparts appropriate physical strength to the cured product obtained from the curable perfluoropolyether pressure-sensitive adhesive composition, while also serving to uniformly disperse the organohydrogensiloxane of component (G), described below, throughout the composition. The hydrophobic silica powder of component (F) is preferably a silica powder having a BET specific surface area of ​​50 m, which is known as a filler for silicone rubber. 2 / g or more, especially 50-400m 2 / g of finely powdered silica that has been hydrophobized is preferred.

[0097] Examples of finely powdered silica include fumed silica (fumed silica or dry silica), precipitated silica (wet silica), and colloidal silica, with fumed silica being the most preferred of these.

[0098] BET specific surface area is 50m 2 If the viscosity is 400m / g or more, the physical strength of the resulting cured product is sufficient, and the component (G) is uniformly dispersed. 2 If the specific surface area is 0.01 / g or less, the kneading operation becomes easy and the component (F) itself is dispersed uniformly. The BET specific surface area in the present invention can be measured in accordance with DIN 66131.

[0099] Examples of hydrophobic treatment agents for the above-mentioned finely powdered silica include organochlorosilanes, organodisilazanes, cyclic organopolysilazanes, linear organopolysiloxanes, etc., with organochlorosilanes, organodisilazanes, and cyclic organopolysilazanes being preferred.

[0100] When component (F) is incorporated into the composition of the present invention, the amount is preferably 0.5 to 20 parts by mass, more preferably 1 to 18 parts by mass, per 100 parts by mass of component (A) or per 100 parts by mass of the total of component (A) and component (D), which will be described later. When the amount is 0.5 parts by mass or more, the effect of incorporating this component is reliably achieved. On the other hand, when the amount is 20 parts by mass or less, the fluidity of the composition is not reduced, and the coatability to the substrate is improved.

[0101] [(G) component] Furthermore, in order to impart adhesiveness, a known adhesion promoter "component (G)" containing an epoxy group, an alkoxy group, or the like can also be added.

[0102] In the first embodiment of the present invention (or the second embodiment described below), it is optional to incorporate an adhesion promoter (adhesion aid or adhesion improver) as component (G) as needed.

[0103] The adhesion promoter of component (G) is an optional component that is blended as needed and acts as an aid (adhesion aid or adhesion improver) for improving adhesion to substrates. Examples of such an adhesion promoter include hydrolyzable organosilane compounds (so-called silane coupling agents or carbon functional silanes) having adhesive functional groups (e.g., alkoxy groups, epoxy groups, (meth)acryloxy groups, mercapto groups, etc.) containing heteroatoms such as nitrogen, oxygen, or sulfur in the molecule and / or partial hydrolysis condensates thereof, as well as organosilicon compounds such as organohydrogensilanes having such adhesive functional groups in the molecule and organohydrogenpolysiloxanes having such adhesive functional groups in the molecule. Such organosilicon compounds are preferably organosilicon compounds (organo(hydrogen)silanes, organo(hydrogen)polysiloxanes) having in one molecule at least two or more adhesive functional groups selected from hydrogen atoms bonded to silicon atoms (SiH groups), epoxy groups bonded to silicon atoms via carbon atoms or carbon atoms and oxygen atoms, and trialkoxysilyl groups bonded to silicon atoms via carbon atoms or carbon atoms and oxygen atoms, and more preferably organopolysiloxanes having, in addition to the two or more adhesive functional groups described above, one or more monovalent perfluoroalkyl groups or monovalent perfluorooxyalkyl groups bonded to silicon atoms via a divalent linking group containing a carbon atom bonded to a silicon atom or a carbon atom and an oxygen atom (i.e., fluorine-containing organo(hydrogen)polysiloxanes having adhesive functional groups). Among the organosilicon compounds of component (G), the fluorine-containing organohydrogenpolysiloxane containing an adhesive functional group differs from the fluorine-containing organohydrogenpolysiloxane of component (B) described above in that it contains an adhesive functional group having a heteroatom such as nitrogen, oxygen or sulfur in the molecule (e.g., an alkoxy group, an epoxy group, a (meth)acryloxy group, a mercapto group, etc.).

[0104] The siloxane skeleton of such organopolysiloxane may be cyclic, linear, branched, or a mixture of these.

[0105] Specific examples of the component (G) that can be used include organosilane compounds containing adhesive functional groups, such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltriethoxysilane, β-(2,3-epoxycyclohexyl)ethyltrimethoxysilane, and β-(2,3-epoxycyclohexyl)ethyltriethoxysilane, as well as organopolysiloxanes represented by the following general formula:

[0106] [ka] (In the formula, R 1 ' are independently unsubstituted or halogen-substituted monovalent hydrocarbon groups, and A and B are as shown below. w is an integer of 0≦w≦100, x is an integer of 1≦x≦100, y is an integer of 1≦y≦100, and z is an integer of 0≦z≦100.

[0107] R 1 The halogen-substituted or unsubstituted monovalent hydrocarbon group represented by ' preferably has 1 to 10 carbon atoms, particularly 1 to 8 carbon atoms. Specific examples include alkyl groups such as methyl, ethyl, propyl, butyl, hexyl, cyclohexyl, and octyl; aryl groups such as phenyl and tolyl; aralkyl groups such as benzyl and phenylethyl; and substituted monovalent hydrocarbon groups in which some or all of the hydrogen atoms of these groups have been substituted with halogen atoms such as fluorine, and of these, methyl is particularly preferred.

[0108] w is preferably an integer of 0≦w≦20, x is preferably an integer of 1≦x≦20, y is preferably an integer of 1≦y≦20, z is preferably an integer of 1≦z≦20, and 3≦w+x+y+z≦50 is preferred.

[0109] A represents an epoxy group bonded to a silicon atom via a carbon atom or a carbon atom and an oxygen atom and / or a trialkoxysilyl group bonded to a silicon atom via a carbon atom or a carbon atom and an oxygen atom, and specific examples include the following groups:

[0110] [ka] [In the formula, R 2 ' represents a divalent hydrocarbon group (such as an alkylene group or cycloalkylene group) having 1 to 10 carbon atoms, particularly 1 to 5 carbon atoms, optionally containing an oxygen atom.

[0111] -R 3 -Si(OR 4 )3 [In the formula, R 3 represents a divalent hydrocarbon group (such as an alkylene group) having 1 to 10 carbon atoms, especially 1 to 4 carbon atoms, and R 4 represents a monovalent hydrocarbon group (such as an alkyl group) having 1 to 8 carbon atoms, particularly 1 to 4 carbon atoms.

[0112] [ka] [In the formula, R 5 represents a monovalent hydrocarbon group (such as an alkyl group) having 1 to 8 carbon atoms, especially 1 to 4 carbon atoms, and R 6 represents a hydrogen atom or a methyl group, and k represents an integer of 2 to 10.

[0113] B represents a monovalent perfluoroalkyl or perfluorooxyalkyl group bonded to a silicon atom via a carbon atom or a carbon atom and an oxygen atom. Examples of the monovalent perfluoroalkyl or perfluorooxyalkyl group include those represented by the following general formula:

[0114] C g’ F 2g’+1 - (In the formula, g' is an integer of 1 to 20, preferably an integer of 2 to 10.)

[0115] F-[CF(CF3)CF2O] f’ -C h’ F 2h’ - (In the formula, f' is an integer of 2 to 200, preferably an integer of 2 to 100, and h' is an integer of 1 to 3.)

[0116] The divalent linking group containing a carbon atom or a carbon atom and an oxygen atom may be an alkylene group, an arylene group, or a combination thereof, or these groups may be linked via an ether bond oxygen atom, an amide bond, a carbonyl bond, or the like, and examples thereof include: -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2OCH2-, -CH2CH2CH2-NH-CO-, -CH2CH2CH2-N(CH3)-CO-, -CH2CH2CH2-N(Ph)-CO- (wherein Ph is a phenyl group.) Examples of divalent linking groups having 2 to 12 carbon atoms include the following.

[0117] These organopolysiloxanes can be obtained by subjecting an organohydrogenpolysiloxane having three or more silicon-bonded hydrogen atoms (Si-H groups) per molecule to a partial addition reaction, according to a conventional method, with a compound containing an aliphatic unsaturated group such as a vinyl group or an allyl group, an epoxy group and / or a trialkoxysilyl group, and optionally a compound containing an aliphatic unsaturated group and a perfluoroalkyl group or a perfluorooxyalkyl group. Note that the number of the aliphatic unsaturated groups must be less than the number of Si-H groups.

[0118] In producing this organopolysiloxane, the target substance may be isolated after the reaction is complete, but it is also possible to use the mixture from which the unreacted materials and addition reaction catalyst have simply been removed.

[0119] Specific examples of organopolysiloxanes of component (G) include those represented by the following structural formula: In the following formula, Me is a methyl group, and Ph is a phenyl group.

[0120] [ka]

[0121] [ka]

[0122] [ka] (o, q, r are positive integers, and p is an integer greater than or equal to 0.)

[0123] [ka]

[0124] [ka]

[0125] [ka]

[0126] [ka] (o, q, r are positive integers, and p is an integer greater than or equal to 0.)

[0127] [ka]

[0128] [ka]

[0129] The component (G) may be used alone or in combination of two or more types.

[0130] The amount of component (G) blended is in the range of 0.05 to 5.0 parts by mass, preferably 0.1 to 3.0 parts by mass, and more preferably 0.2 to 1.0 parts by mass, per 100 parts by mass of component (A), or in the second embodiment of the present invention described below, per 100 parts by mass of the total of component (A) and component (D) described below. If the amount is 0.05 parts by mass or more, the effect of blending this component can be reliably obtained, and if the amount is 5.0 parts by mass or less, the fluidity of the composition will not be impaired and curability will not be inhibited.

[0131] <Second aspect> A second aspect of the present invention is a curable perfluoropolyether pressure-sensitive adhesive composition that gives a rubber-like cured product (cured perfluoropolyether rubber product) or a gel-like cured product (cured perfluoropolyether gel product), comprising: (A) A compound having at least two alkenyl groups in one molecule and having -C in the main chain a F 2a Linear perfluoropolyether compound having a perfluoropolyether structure containing a repeating unit represented by O- (wherein a represents an integer of 1 to 6): 100 to 40 parts by mass (D) Polyfluoromonoalkenyl compound having one alkenyl group per molecule and having a perfluoropolyether structure in the main chain: 0 to 60 parts by mass (provided that the total amount of the components (A) and (D) is 100 parts by mass). (B) a fluorine-containing organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms per molecule: a curing effective amount (C) Hydrosilylation reaction catalyst: catalytic amount and wherein the composition does not contain any organic solvent.

[0132] In the second embodiment of the present invention, the components (A) to (C) can be the same as those explained above.

[0133] [(D) component] Component (D) is a component used in a specific second embodiment (i.e., a composition that produces a cured gel product) of the curable perfluoropolyether pressure-sensitive adhesive composition of the present invention, as opposed to the first embodiment (i.e., a composition that produces a cured rubber product) of the present invention described above, and is a polyfluoromonoalkenyl compound having one alkenyl group per molecule and a perfluoropolyether structure in the main chain. In particular, polyfluoromonoalkenyl compounds represented by the following general formula (2) are preferred:

[0134] Rf 1 -(X') p -CH=CH2(2) [wherein X′ and p are the same as those described in the general formula (1) above, and Rf 1 is a perfluoropolyether structure (monovalent perfluoropolyether group) represented by the following general formula. F-[CF(CF3)CF2O] w -CF(CF3)- (wherein w represents an integer of 1 to 500, preferably an integer of 2 to 200).

[0135] Specific examples of the polyfluoromonoalkenyl compound represented by the above general formula (2) include the following.

[0136] [ka]

[0137] [ka] (In the above formula, m is an integer of 1 to 200, particularly an integer of 2 to 100.)

[0138] When the polyfluoromonoalkenyl compound of component (D) is blended, the blending amount is selected so that the ratio of the linear perfluoropolyether dialkenyl compound of component (A) and component (D) in the curable perfluoropolyether pressure-sensitive adhesive composition is 100 to 40 parts by mass of component (A) and 0 to 60 parts by mass of component (D), with the total of component (A) and component (D) being 100 parts by mass.

[0139] For example, the perfluoropolyether pressure-sensitive adhesive composition of the second aspect of the present invention may contain component (D) in an amount of 0.1 to 60 parts by mass, preferably 1 to 60 parts by mass, particularly 5 to 50 parts by mass, and even more preferably 8 to 40 parts by mass, per 99.9 to 40 parts by mass, preferably 99 to 40 parts by mass, particularly 95 to 50 parts by mass, and even more preferably 92 to 60 parts by mass of component (A), and such that the total of components (A) and (D) is 100 parts by mass. The polyfluoromonoalkenyl compound of component (D) may be used alone or in combination of two or more types.

[0140] [Other ingredients] In the second embodiment of the present invention, various compounding ingredients may be optionally added in addition to the above components (A) to (D), as in the first embodiment. Examples of the hydrosilylation reaction catalyst inhibitor (E), hydrophobic silica powder (F), and adhesive functional group-containing organosilicon compound (G) are the same as those described above.

[0141] [Cured product] The perfluoropolyether pressure-sensitive adhesive composition of the present invention is obtained by curing the above-described composition to form a pressure-sensitive adhesive comprising a cured product of perfluoropolyether rubber or gel having a surface adhesion of, for example, 0.001 to 10.0 N / 25 mm, preferably 0.002 to 8.0 N / 25 mm, and more preferably 0.003 to 6.0 N / 25 mm. This pressure-sensitive adhesive composition is excellent in heat resistance, water repellency, oil repellency, weather resistance, chemical resistance, solvent resistance, etc., and can form a cured product (pressure-sensitive adhesive) that has good adhesion to resins and metal substrates, and can be used for a variety of applications.

[0142] For example, in the first embodiment of the present invention, the perfluoropolyether pressure-sensitive adhesive composition can be formed by curing 100 parts by mass of component (A), component (B) in an amount such that the hydrosilyl groups in component (B) are 0.2 to 3.0 moles per mole of the total alkenyl groups in component (A) of 1, and component (C) in an amount of 0.1 to 100 ppm, calculated as platinum, relative to the total amount of components (A) and (B).

[0143] Furthermore, for example, in a second embodiment of the present invention, the perfluoropolyether pressure-sensitive adhesive composition can be formed by curing 40 to 80 parts by mass of component (A), 20 to 60 parts by mass of component (D), and a total of 100 parts by mass of components (A) and (D), an amount of component (B) such that the hydrosilyl groups of component (B) are 0.2 to 3.0 moles per mole of alkenyl groups in components (A) and (D) combined, and 0.1 to 100 ppm of component (C) in terms of platinum relative to the total amount of components (A), (B), and (D).

[0144] The formation of a cured product of the above-mentioned perfluoropolyether pressure-sensitive adhesive composition is carried out by coating each composition of the present invention on a suitable substrate and then curing it, or by laminating them together using a conventionally known method. Curing can usually be easily carried out by heat treatment at a temperature of 60 to 150°C for about 1 to 60 minutes.

[0145] Pressure-sensitive adhesives using the cured product of the perfluoropolyether pressure-sensitive adhesive composition of the present invention can be used as components for automobiles, chemical plants, semiconductor production lines, analytical and physical / chemical equipment, medical equipment, aircraft, optical applications, etc.

[0146] Furthermore, for example, an adhesive tape obtained by laminating a layer of the cured product of the curable perfluoropolyether adhesive composition of the present invention (cured perfluoropolyether rubber or cured perfluoropolyether gel) on a substrate made of an organic resin film such as a polyethylene terephthalate (PET) film is useful as an adhesive tape having a non-conductive adhesive layer that has excellent heat resistance, oil resistance, low-temperature properties, moisture resistance, low gas permeability, etc., and is particularly excellent in chemical resistance and solvent resistance.

[0147] Furthermore, when coating the pressure-sensitive adhesive composition of the present invention, it is useful to use a known primer in combination to improve adhesion or bondability to a substrate. The primer can prevent penetration of chemicals and solvents from the substrate interface, and can improve the acid resistance, chemical resistance, and solvent resistance of the entire part.

[0148] Examples of primers that can be used include silane-based primers containing a silane coupling agent as a main component, primers containing organohydrogenpolysiloxane as a main component, primers containing synthetic rubber as a main component, primers containing acrylic resin as a main component, primers containing urethane resin as a main component, and primers containing epoxy resin as a main component, as well as compositions in which an adhesion promoter has been added to the perfluoropolyether rubber composition of the present invention.

[0149] Furthermore, the cured product of the curable perfluoropolyether pressure-sensitive adhesive composition of the present invention (cured perfluoropolyether rubber or cured perfluoropolyether gel) has a volume resistivity of 1×10 9 Preferably, the pressure-sensitive adhesive has a non-conductive resistance of Ω·cm or more. Such a curable perfluoropolyether pressure-sensitive adhesive composition of the present invention is suitable as a material for a non-conductive pressure-sensitive adhesive. The upper limit of the volume resistivity of the cured product of the curable perfluoropolyether pressure-sensitive adhesive composition of the present invention is not particularly limited, but may be, for example, 1×10 13 It can be expressed as Ω·cm.

[0150] Such a perfluoropolyether pressure-sensitive adhesive composition of the present invention is a curable perfluoropolyether pressure-sensitive adhesive composition that gives a cured product (pressure-sensitive adhesive) that has excellent heat resistance, weather resistance, oil resistance, low-temperature properties, moisture resistance, low gas permeability, water repellency, oil repellency, etc., and in particular, is free from voids derived from organic solvents on the film surface after application to a substrate, forming a smooth coating film.

[0151] A third aspect of the present invention is a pressure-sensitive adhesive comprising the cured product (cured perfluoropolyether rubber or cured perfluoropolyether gel) of the curable perfluoropolyether pressure-sensitive adhesive composition of the present invention as explained above.

[0152] As explained above, the perfluoropolyether pressure-sensitive adhesive composition of the present invention provides a cured product (pressure-sensitive adhesive) excellent in heat resistance, weather resistance, oil resistance, chemical resistance, solvent resistance (solvent resistance), low-temperature properties, moisture resistance, low gas permeability, water repellency, oil repellency, etc., and further provides a void-free, smooth coating film on the surface after curing. Therefore, the pressure-sensitive adhesive of the present invention provides excellent heat resistance, weather resistance, oil resistance, chemical resistance, solvent resistance (solvent resistance), low-temperature properties, moisture resistance, low gas permeability, water repellency, oil repellency, etc., and provides a void-free, smooth coating film on the surface after curing.

[0153] Furthermore, a fourth aspect of the present invention is a pressure-sensitive adhesive tape having a layer of the cured product of the curable perfluoropolyether pressure-sensitive adhesive composition of the present invention laminated thereon, as explained above.

[0154] As explained above, the perfluoropolyether pressure-sensitive adhesive composition of the present invention gives a cured product (pressure-sensitive adhesive) excellent in heat resistance, weather resistance, oil resistance, chemical resistance, solvent resistance (solvent resistance), low-temperature properties, moisture resistance, low gas permeability, water repellency, oil repellency, etc., and furthermore, after curing, the film surface is free of voids and forms a smooth coating film. Therefore, the pressure-sensitive adhesive tape of the present invention is excellent in heat resistance, weather resistance, oil resistance, chemical resistance, solvent resistance (solvent resistance), low-temperature properties, moisture resistance, low gas permeability, water repellency, oil repellency, etc., and furthermore, after curing, the film surface is free of voids and forms a smooth coating film.

[0155] Furthermore, in order to enhance the effect of surface modification, the surface of the substrate may be subjected to a degreasing treatment using an organic solvent or a pre-baking treatment before the plasma irradiation. [Example]

[0156] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples. In the following examples, % indicates % by mass.

[0157] [Examples 1 to 5, Comparative Examples 1 to 5] The curable perfluoropolyether pressure-sensitive adhesive compositions shown in Table 1 were prepared using the following raw materials. These pressure-sensitive adhesive compositions were cured at 130°C for 5 minutes, and the surface adhesive strength of each cured product was measured. In addition, solvent resistance tests, pencil hardness tests, adhesion tests, and coating surface condition observations were conducted using the methods described below. The results are also shown in Table 1.

[0158] raw material (A) Linear perfluoropolyether compound (a-1) Bifunctional perfluoropolyether (perfluoropolyether 1) [ka] (a-2) Bifunctional perfluoropolyether (perfluoropolyether 2) CH2=CH―CH2―O―CH2―Rf―CH2―O-CH2―CH=CH2 (Rf:-CF2O(CF2CF2O) 20.8 (CF2O) 22.1 CF2-, However, the repeating units CF2CF2O and CF2O are arranged randomly.

[0159] (B) Organohydrogenpolysiloxane (b-1) Organohydrogensiloxane 1 [ka] (b-2) Organohydrogensiloxane 2 [ka]

[0160] (C) Addition reaction catalyst (platinum compound) (c-1) CAT-PL-56 (product name manufactured by Shin-Etsu Chemical Co., Ltd. / organic solvent-free product) (c-2) CAT-PL-50T (product name, manufactured by Shin-Etsu Chemical Co., Ltd. / contains toluene)

[0161] (D) Monofunctional perfluoropolyether compound (perfluoropolyether 3) [ka]

[0162] (E) Curing inhibitor (e-1) Ethynylcyclohexanol (e-2) Ethynylcyclohexanol / 50% toluene solution

[0163] (F) Hydrophobic silica powder (compounded as base compound F below)

[0164] Preparation of Base Compound F 100 parts of the polymer represented by the above formula (a-1) was charged into a planetary mixer, and while maintaining the internal temperature at 50 to 100°C, fumed silica (BET specific surface area 110 m) surface-treated with dimethyldichlorosilane was added. 2 10 parts of 1 / g of PEG-400 was added in portions. Then, heating was stopped and the mixture was kneaded under reduced pressure (gauge pressure: -0.093 MPa) for 1 hour. The kneading was continued while heating the apparatus, and after the internal temperature reached 130°C, the mixture was heat-treated under reduced pressure (gauge pressure: -0.093 MPa) for 1 hour while maintaining the temperature at 130-160°C. The contents were then cooled to below 40°C, removed, and passed through a three-roll mill twice to obtain base compound F (base F).

[0165] (G) Organosilicon compounds containing adhesive functional groups (Adhesion-imparting siloxane compound (siloxane compound 1)) [ka]

[0166] Adhesion measurement Each composition in the Examples and Comparative Examples was applied to a 50 μm-thick, 25 mm-wide PET (polyethylene terephthalate) film using an applicator to a thickness of 30 μm, and then heated at 130°C for 5 minutes to harden into a rubber or gel form. This produced an adhesive tape consisting of a 30 μm-thick adhesive layer (rubber or cured gel layer) laminated on a 50 μm-thick PET film. This adhesive tape was attached to a metal plate (polished stainless steel plate), and a 2 kg rubber-coated roller was rolled back and forth across the tape substrate to press the adhesive tape into place. After leaving the tape at room temperature for 20 hours, the adhesive strength of each adhesive layer (rubber or cured gel layer) was measured at 25°C using a tensile tester, measuring the force (N / 25 mm) required to peel the adhesive tape from the stainless steel plate at a pulling rate of 300 mm / min at an angle of 180°.

[0167] Solvent resistance test (weight change) 3 g of the compositions of the examples and comparative examples were filled into a 32 mm diameter x 15 mm glass container, and then cured at 130°C for 5 minutes to prepare samples. These samples were then immersed in xylene and Fuel C (a 50 / 50 (wt%) mixed solution of toluene and isooctane) at 25°C for 7 days, and the weight change rate before and after immersion was measured.

[0168] Pencil hardness (scratch resistance) test In accordance with JIS K5600-5-4, the hardness of the pencil lead was determined by the hardness at which scratches were produced when scratched at 45° with the pencil lead.

[0169] Adhesion Test Each composition of the Examples and Comparative Examples was applied to an epoxy glass substrate to a thickness of 100 μm, and then heated at 130° C. for 5 minutes to harden into a rubber or gel state, producing a substrate with a laminated adhesive layer. The adhesive layer on the substrate was rubbed with a finger 10 times, and samples that did not peel from the substrate were marked with an O, and samples that peeled and exposed the substrate surface were marked with an X.

[0170] Observation of coating surface condition Substrates were prepared in the same manner as in the above adhesion test, and the adhesive layer on the substrate was then observed under an optical microscope. Those in which no voids were observed were marked with a circle, and those in which voids were observed were marked with an x.

[0171] [Table 1]

[0172] As shown in Table 1, adhesives such as those in Examples 1 to 5, which used the curable perfluoropolyether adhesive composition of the present invention, not only had good adhesion to substrates, but also had no voids on the film surface after curing. In contrast, Comparative Examples 1 and 2, which did not contain component (B) or component (C), which are essential components of the present invention, did not cure, and Comparative Examples 3 to 5, which contained organic solvents in the compositions due to the inclusion of organic solvents in component (C) or component (E), had voids on the film surface after curing.

[0173] From the above, it has been found that the present invention provides a curable perfluoropolyether pressure-sensitive adhesive composition that has excellent heat resistance, weather resistance, water repellency, oil repellency, chemical resistance and solvent resistance, and that does not generate voids on the coating surface, particularly during the heating process.

[0174] The present invention is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits similar effects is included within the technical scope of the present invention.

Claims

1. A heat-curable perfluoropolyether pressure-sensitive adhesive composition, (A) A polymer having at least two alkenyl groups in one molecule and a -C group in the main chain ａ F ２ａ Linear perfluoropolyether compound having a perfluoropolyether structure containing a repeating unit represented by the formula: O- (wherein a represents an integer of 1 to 6): 100 parts by mass (B) a fluorine-containing organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms in one molecule and having one or more perfluorooxyalkyl groups and perfluorooxyalkylene groups represented by the following formulas (T1) to (T3): 【Chemistry 1】 (In the formula, f is an integer of 1 to 200, and h is an integer of 1 to 3.) 【Chemistry 2】 (In the formula, i and j are each an integer of 1 or more, and the average of i+j is 2 to 200.) -(CF ２ O) ｄ -(CF ２ CF ２ O) ｅ -CF ２ - (T3) (In the formula, d and e are each an integer of 1 to 50.) (C) Hydrosilylation reaction catalyst: catalytic amount A heat-curable perfluoropolyether pressure-sensitive adhesive composition comprising the above compound and containing no organic solvent.

2. The heat-curable perfluoropolyether pressure-sensitive adhesive composition according to claim 1, further comprising (E) an organic solvent-free addition reaction inhibitor in an amount of 0.01 to 5 parts by mass per 100 parts by mass of component (A).

3. 3. The heat-curable perfluoropolyether pressure-sensitive adhesive composition according to claim 1, further comprising, as component (F), 0.5 to 20 parts by mass of hydrophobic silica powder per 100 parts by mass of component (A).

4. A heat-curable perfluoropolyether pressure-sensitive adhesive composition, (A) A polymer having at least two alkenyl groups in one molecule and a -C group in the main chain ａ F ２ａ Linear perfluoropolyether compound having a perfluoropolyether structure containing a repeating unit represented by the formula: O- (wherein a represents an integer of 1 to 6): 100 to 40 parts by mass (D) Polyfluoromonoalkenyl compound having one alkenyl group per molecule and a perfluoropolyether structure in the main chain: 0 to 60 parts by mass (provided that the total amount of the components (A) and (D) is 100 parts by mass). (B) a fluorine-containing organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms in one molecule and having one or more perfluorooxyalkyl groups and perfluorooxyalkylene groups represented by the following formulas (T1) to (T3): 【Transformation 3】 (In the formula, f is an integer of 1 to 200, and h is an integer of 1 to 3.) 【Chemistry 4】 (In the formula, i and j are each an integer of 1 or more, and the average of i+j is 2 to 200.) -(CF ２ O) ｄ -(CF ２ CF ２ O) ｅ -CF ２ - (T3) (In the formula, d and e are each an integer of 1 to 50.) (C) Hydrosilylation reaction catalyst: catalytic amount A heat-curable perfluoropolyether pressure-sensitive adhesive composition comprising the above compound and containing no organic solvent.

5. 5. The heat-curable perfluoropolyether pressure-sensitive adhesive composition according to claim 4, comprising 99.9 to 40 parts by mass of the component (A) and 0.1 to 60 parts by mass of the component (D) (wherein the total amount of the component (A) and the component (D) is 100 parts by mass).

6. The component (D) is represented by the following general formula (2): Rf １ -(X’) ｐ -CH=CH ２ (2) [wherein X' is -CH ２ -, -OCH ２ -, -CH ２ OCH ２ -, or -CO-NR ２ -Y'- (wherein Y' is -CH ２ - or a group represented by the following structural formula (Z'): 【Transformation 5】 R ２ is a hydrogen atom, a methyl group, a phenyl group, or an allyl group; and p is 0 or 1. １ is represented by the general formula F-[CF(CF ３ )CF ２ O] ｗ -CF (CF ３ 6. The heat-curable perfluoropolyether pressure-sensitive adhesive composition according to claim 4, wherein the polyfluoromonoalkenyl compound is a perfluoropolyether structure represented by the formula:

7. The heat-curable perfluoropolyether pressure-sensitive adhesive composition according to any one of claims 4 to 6, further comprising (E) an organic solvent-free addition reaction inhibitor in an amount of 0.01 to 5 parts by mass per 100 parts by mass of the total of the components (A) and (D).

8. The heat-curable perfluoropolyether pressure-sensitive adhesive composition according to any one of claims 4 to 7, further comprising, as component (F), 0.5 to 20 parts by mass of hydrophobic silica powder per 100 parts by mass of the total of the components (A) and (D).

9. 9. The heat-curable perfluoropolyether pressure-sensitive adhesive composition according to claim 1, wherein the component (C) does not contain an organic solvent.

10. The component (A) is represented by the following general formula (1): 【Transformation 6】 [Wherein X is —CH ２ -, -CH ２ O-, -CH ２ OCH ２ - or -Y-NR １ -CO- (where Y is -CH ２ - or a group represented by the following structural formula (Z), R １ is a hydrogen atom, a methyl group, a phenyl group, or an allyl group. ２ -, -OCH ２ -, -CH ２ OCH ２ -, or -CO-NR ２ -Y'- (wherein Y' is -CH ２ - or a group represented by the following structural formula (Z'), R ２ is a hydrogen atom, a methyl group, a phenyl group, or an allyl group. p is independently 0 or 1, r is an integer of 2 to 6, m and n are each an integer of 0 to 600, and the sum of m and n is 50 to 600. 【Transformation 7】 【Transformation 8】 ］ The heat-curable perfluoropolyether pressure-sensitive adhesive composition according to any one of claims 1 to 9, wherein the compound is a linear perfluoropolyether compound represented by the formula:

11. The heat-curable perfluoropolyether pressure-sensitive adhesive composition according to any one of claims 1 to 10, which upon curing forms a pressure-sensitive adhesive having an adhesive strength of 0.001 N / 25 mm to 10.0 N / 25 mm.

12. The cured product of the heat-curable perfluoropolyether pressure-sensitive adhesive composition has a volume resistivity of 1×10 ９ The heat-curable perfluoropolyether pressure-sensitive adhesive composition according to any one of claims 1 to 11, which is a non-conductive pressure-sensitive adhesive having a resistance of Ω·cm or more.

13. 2. The heat-curable perfluoropolyether pressure-sensitive adhesive composition according to claim 1, wherein the amount of component (B) is such that the number of silicon-bonded hydrogen atoms in component (B) is 0.2 to 4 moles per mole of the total number of alkenyl groups in component (A).

14. The heat-curable perfluoropolyether pressure-sensitive adhesive composition according to claim 4, wherein the amount of component (B) is such that the number of silicon-bonded hydrogen atoms in component (B) is 0.2 to 4 moles per mole of the total number of alkenyl groups in components (A) and (D).

15. The heat-curable perfluoropolyether adhesive composition according to claim 1, wherein the organic solvent is gasified during the heating process.

16. The thermosetting perfluoropolyether pressure-sensitive adhesive composition according to claim 15, wherein the heating temperature in the heating step is 60 to 150°C.

17. An adhesive comprising a cured product of the heat-curable perfluoropolyether adhesive composition described in any one of claims 1 to 16.

18. An adhesive tape comprising a substrate and a cured layer of the heat-curable perfluoropolyether adhesive composition according to any one of claims 1 to 16 laminated thereon.

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