Addition-curable silicone pressure-sensitive adhesive composition and cured product thereof

Abstract

To provide an addition-curable silicone pressure-sensitive adhesive composition capable of achieving excellent tackiness for temporary fixing and producing a cured product with extremely low migration of material components.SOLUTION: An addition-curable silicone pressure-sensitive adhesive composition comprises: (A) 100 pts.mass of a linear organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in one molecule; (B) 5-500 pts.mass of an organopolysiloxane resin having alkenyl groups; (C) an organohydrogenpolysiloxane having two or more hydrogen atoms bonded to silicon atoms in one molecule, in an amount such that hydrogen atoms bonded to silicon atoms in component (C) are 0.1-5.0 mol relative to the total alkenyl groups bonded to the total silicon atoms in the composition; (D) 1-10,000 pts.mass of a saturated aliphatic hydrocarbon compound having 10-20 carbon atoms; and (E) a platinum-group metal catalyst, the composition containing no non-crosslinkable organopolysiloxane.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an addition-curable silicone pressure-sensitive adhesive composition and a cured product thereof, and more specifically to an addition-curable silicone pressure-sensitive adhesive composition and a cured product thereof that can be suitably used as a temporary fixing material for minute objects. [Background technology]

[0002] In recent years, electronic devices such as smartphones, displays, and in-vehicle components are being required to not only improve performance but also to save space and energy. In response to such societal demands, the electrical and electronic components used are becoming increasingly smaller and finer, and the assembly process is becoming more complex and difficult every year.

[0003] Micro LEDs are an example of semiconductor devices that are becoming increasingly miniaturized. Micro LEDs are extremely small, ranging in size from a few μm to a few tens of μm, making it difficult to transfer them using a general LED bonder, etc. Therefore, adhesive articles made by curing and molding a silicone adhesive composition on a substrate, etc., are used as temporary fixing materials for transferring micro LEDs.

[0004] In such microtransfer printing materials, if a tackifier component that is not involved in the crosslinking of the silicone is included, it can cause glue transfer and the silicone material may remain on the element, etc. For this reason, Patent Document 1 proposes an addition-curing adhesive silicone material that has sufficient adhesive power and strength without including a non-crosslinking solid resin component as a tackifier.

[0005] In addition, since the thickness of micro LEDs is generally less than 10 μm, a silicone material that can be applied smoothly to the substrate with little variation in thickness is desired so that all micro LEDs can be handled uniformly during the transfer process in which the substrates are bonded together. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-123620 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made in view of the above circumstances, and has as its object to provide an addition-curable silicone pressure-sensitive adhesive composition which, before curing, can be applied smoothly to a substrate with little thickness variation, and which, after curing, gives a cured product which has excellent adhesive properties as a temporary fixing material and which shows very little migration of the silicone material components, and a cured product thereof. [Means for solving the problem]

[0008] As a result of extensive research conducted by the present inventors in order to achieve the above-mentioned object, they discovered that by using a linear organopolysiloxane having alkenyl groups, an organohydrogenpolysiloxane, a polysiloxane resin having alkenyl groups, and a saturated aliphatic hydrocarbon compound, it is possible to obtain an addition-curable silicone pressure-sensitive adhesive composition that can be applied smoothly to a substrate and that gives a cured product with good adhesive properties even without containing a non-crosslinkable resin component such as an MQ resin (a polysiloxane composed of M units and Q units), thereby completing the present invention.

[0009] That is, the present invention is 1. (A) 100 parts by mass of a linear organopolysiloxane having at least two alkenyl groups bonded to silicon atoms per molecule, (B) organopolysiloxane resin having an alkenyl group: 5 to 500 parts by mass, (C) an organohydrogenpolysiloxane having two or more silicon-bonded hydrogen atoms per molecule: an amount such that the number of silicon-bonded hydrogen atoms in component (C) is 0.1 to 5.0 times the molar amount of all silicon-bonded alkenyl groups in the composition; (D) saturated aliphatic hydrocarbon compound having 10 to 20 carbon atoms: 1 to 10,000 parts by mass, and, (E) Platinum group metal catalyst an addition-curable silicone pressure-sensitive adhesive composition comprising the above and not containing a non-crosslinkable organopolysiloxane; 2. An addition-curable silicone pressure-sensitive adhesive composition according to item 1, which contains 0.01 to 5.0 parts by mass of a reaction inhibitor (F) per 100 parts by mass of component (A). 3. The addition-curable silicone pressure-sensitive adhesive composition of 1 or 2, which does not contain a compound having an alkoxysilyl group, a compound having an epoxy-containing group, or a compound having an alkenyl group other than components (A) and (B); 4. A silicone cured product obtained by curing the addition-curable silicone pressure-sensitive adhesive composition according to any one of 1 to 3. 5. The silicone cured product of 4, having an adhesive strength of 0.001 MPa or more; 6. A silicone cured product according to 4 or 5, having a tensile strength of 0.3 MPa or more. 7. An adhesive comprising a silicone cured product according to any one of 4 to 6. 8. An adhesive sheet comprising a silicone cured product according to any one of 4 to 6. 9. A microstructure-holding substrate having an adhesive layer made of a silicone cured product according to any one of 4 to 6. 10. Microstructure transfer device equipped with 9 microstructure holding substrates to provide. [Effects of the Invention]

[0010] The addition-curable silicone pressure-sensitive adhesive composition of the present invention can be applied smoothly to a substrate with little variation in thickness, and after curing has excellent adhesive properties as a temporary fixing material, with very little material transfer when peeled off. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram showing an example of a holding substrate for transferring a microstructure of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention will be specifically described below. The addition-curable silicone pressure-sensitive adhesive composition according to the present invention comprises: (A) a linear organopolysiloxane having at least two alkenyl groups bonded to silicon atoms per molecule: 100 parts by mass, (B) organopolysiloxane resin having an alkenyl group: 5 to 500 parts by mass, (C) an organohydrogenpolysiloxane having two or more silicon-bonded hydrogen atoms per molecule: an amount such that the number of silicon-bonded hydrogen atoms in component (C) is 0.1 to 5.0 times the molar amount of all silicon-bonded alkenyl groups in the composition; (D) saturated aliphatic hydrocarbon compound having 10 to 20 carbon atoms: 1 to 10,000 parts by mass, and, (E) Platinum group metal catalyst The compound is characterized by containing:

[0013] (A) Organopolysiloxane Component (A) is the crosslinking component of the composition and is a linear organopolysiloxane having alkenyl groups bonded to at least two silicon atoms in each molecule. The alkenyl group bonded to the silicon atom is not particularly limited, but is preferably an alkenyl group having 2 to 10 carbon atoms, and more preferably an alkenyl group having 2 to 8 carbon atoms. Specific examples thereof include vinyl, allyl, 1-butenyl, 1-hexenyl, etc. Among these, vinyl is preferred from the standpoint of ease of synthesis and cost. The alkenyl groups may be present either at the terminals or in the middle of the molecular chain of the organopolysiloxane, but from the standpoint of flexibility, it is preferable that they be present only at both terminals.

[0014] The organic group other than the alkenyl group bonded to the silicon atom is not particularly limited, but is preferably a monovalent hydrocarbon group having 1 to 20 carbon atoms, more preferably a monovalent hydrocarbon group having 1 to 10 carbon atoms. Specific examples thereof include alkyl groups such as methyl, ethyl, n-propyl, n-butyl, n-hexyl, and n-dodecyl; aryl groups such as phenyl; and aralkyl groups such as 2-phenylethyl and 2-phenylpropyl. In addition, some or all of the hydrogen atoms of these hydrocarbon groups may be substituted with halogen atoms such as chlorine, fluorine, or bromine, and specific examples thereof include halogen-substituted monovalent hydrocarbon groups such as a fluoromethyl group, a bromoethyl group, a chloromethyl group, and a 3,3,3-trifluoropropyl group. Among these, it is preferable that 90 mol % or more of the groups be methyl groups in terms of ease of synthesis and cost. Therefore, the component (A) is particularly preferably a dimethylpolysiloxane both ends of which are blocked with dimethylvinylsilyl groups.The component (A) may be used alone or in combination of two or more types.

[0015] Specific examples of such component (A) include organopolysiloxanes represented by the following formula, but are not limited to these.

[0016] [ka] (In the formula, Me means a methyl group. The same applies hereinafter.)

[0017] The viscosity of component (A) at 25°C is preferably 0.01 to 1,000 Pa·s, and more preferably 0.05 to 500 Pa·s. A viscosity of 0.01 Pa·s or higher results in excellent adhesive strength of the cured product, while a viscosity of 1,000 Pa·s or lower results in good workability. The above viscosity is measured using a rotational viscometer (hereinafter the same).

[0018] (B) Organopolysiloxane resin Component (B) is a crosslinkable resin containing alkenyl groups, which improves the hardness and strength of the cured product and also contributes to the development of adhesive properties in the cured product. General silicone adhesives are made adhesive by blending non-crosslinkable resins. When such adhesives are used as temporary fixing materials for devices, the non-crosslinkable resin that is not incorporated into the crosslinked structure migrates onto the device. In contrast, the component (B) used in the composition of the present invention contains an alkenyl group, which is incorporated into the crosslinked structure upon curing. This minimizes material migration to elements when the cured product is used as a temporary fixing material.

[0019] The weight-average molecular weight of component (B) is preferably 500 to 30,000, more preferably 1,000 to 20,000. Within this range, the workability of the composition and the adhesive strength of the cured product are improved. The weight-average molecular weight is a value measured by gel permeation chromatography (GPC) in terms of standard polystyrene.

[0020] The content of silicon-bonded alkenyl groups in component (B) is preferably 0.001 to 1.000 mol, and more preferably 0.010 to 0.500 mol, per 100 g of component (B). This range ensures good adhesive strength and mechanical properties of the cured product.

[0021] Component (B) is RSiO 3 / 2 (wherein R represents a substituted or unsubstituted monovalent hydrocarbon group), and a trifunctional siloxane unit (i.e., an organosilsesquioxane unit) represented by the formula: 4 / 2 It is preferred that the copolymer contains at least one branch-forming unit of a tetrafunctional siloxane unit represented by the following formula:

[0022] The organopolysiloxane resin of component (B) may optionally contain monofunctional siloxane units (i.e., triorganosiloxy units) and / or difunctional siloxane units (i.e., diorganosiloxane units), but RSiO 3 / 2 Units and SiO 4 / 2 The total content of the units is preferably 10 mol % or more, and more preferably 20 to 90 mol %, of all siloxane units in the organopolysiloxane resin of component (B).

[0023] The above RSiO 3 / 2 In the unit, the substituted or unsubstituted monovalent hydrocarbon group represented by R preferably has 1 to 10 carbon atoms, and specific examples thereof include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl; cycloalkyl groups such as cyclopentyl, cyclohexyl, and cycloheptyl; alkenyl groups such as vinyl, allyl (2-propenyl), 1-propenyl, isopropenyl, butenyl, pentenyl, hexenyl, and cyclohexenyl (alkenyl groups are used herein to encompass cycloalkenyl groups); aryl groups such as phenyl, tolyl, xylyl, naphthyl, and biphenylyl; aralkyl groups such as benzyl, phenylethyl, and phenylpropyl; and alkaryl groups such as methylbenzyl. Furthermore, one or more hydrogen atoms of these hydrocarbon groups may be substituted with a halogen atom such as a fluorine atom, a chlorine atom, or a bromine atom, or a cyano group. Examples of such substituted hydrocarbon groups include halogenated alkyl groups such as a chloromethyl group, a 2-bromoethyl group, a 3-chloropropyl group, and a 3,3,3-trifluoropropyl group.

[0024] Examples of such component (B) include R 1 3SiO 1 / 2 Units and R 1 R 2 SiO 2 / 2 Units and SiO 4 / 2 a copolymer consisting of R units 1 3SiO 1 / 2 Units and R 1 2SiO 2 / 2 Units and R 1 R 2 SiO 2 / 2 Units and SiO 4 / 2 a copolymer consisting of R units 1 3SiO 1 / 2 Units and R 1 2nd Round 2 SiO 1 / 2 Units and R 12SiO 2 / 2 Units and SiO 4 / 2 a copolymer consisting of R units 1 3SiO 1 / 2 Units and R 1 2nd Round 2 SiO 1 / 2 Units and SiO 4 / 2 a copolymer consisting of R units 1 2nd Round 2 SiO 1 / 2 Units and R 1 2SiO 2 / 2 Units and SiO 4 / 2 a copolymer consisting of R units 1 R 2 SiO 2 / 2 Units and R 1 SiO 3 / 2 Units and / or R 2 SiO 3 / 2 and copolymers consisting of units.

[0025] In the above formula, R 1 is a substituted or unsubstituted monovalent hydrocarbon group that does not have an unsaturated aliphatic bond, and examples thereof include the monovalent hydrocarbon groups exemplified above for R, other than alkenyl groups. Particularly preferred are alkyl groups such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, and n-heptyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; aralkyl groups such as benzyl and phenethyl; and halogenated alkyl groups such as chloromethyl, 3-chloropropyl, and 3,3,3-trifluoropropyl. R 2 is an alkenyl group, and examples thereof include vinyl, allyl, butenyl, pentenyl, hexenyl, and heptenyl groups.

[0026] More specifically, for example, (CH3)3SiO 1 / 2 Units and (CH2=CH)SiO 3 / 2 Units and SiO 4 / 2 A copolymer consisting of (CH2=CH)(CH3)2SiO units 1 / 2 Units and SiO 4 / 2 A copolymer consisting of (CH2=CH)(CH3)2SiO units 1 / 2Units and (CH2=CH)SiO 3 / 2 Units and SiO 4 / 2 A copolymer consisting of (CH3)3SiO units 1 / 2 Units and (CH2=CH)(CH3)2SiO 1 / 2 Units and SiO 4 / 2 and copolymers in which some of the methyl groups have been substituted with phenyl groups.

[0027] Specific examples of component (B) include those represented by the following average unit formula: In the formula, Vi represents a vinyl group (the same applies hereinafter). (Me3SiO 1 / 2 ) 0.35 (ViMe2SiO 1 / 2 ) 0.1 (SiO 4 / 2 ) 0.55 (Me3SiO 1 / 2 ) 0.4 (ViMe2SiO 1 / 2 ) 0.1 (SiO 4 / 2 ) 0.5 (ViMeSiO) 0.4 (Me2SiO) 0.15 (MeSiO 3 / 2 ) 0.45 (ViMe2SiO 1 / 2 ) 0.2 (Me2SiO) 0.25 (MeSiO 3 / 2 ) 0.55 (Me3SiO 1 / 2 ) 0.2 (ViMe2SiO 1 / 2 ) 0.05 (MeSiO 3 / 2 ) 0.75

[0028] The blending amount of component (B) is 5 to 500 parts by mass, preferably 10 to 400 parts by mass, per 100 parts by mass of component (A). If the amount of component (B) is less than 5 parts by mass, sufficient adhesiveness as a temporary fixing material cannot be obtained, and if it exceeds 500 parts by mass, adhesiveness cannot be expressed. Incidentally, the component (B) may be used alone or in combination of two or more thereof.

[0029] (C) Organohydrogenpolysiloxane (C) component contains at least 2 (usually 2 to 300, preferably 3 or more (for example, about 3 to 150)) hydrogen atoms bonded to silicon atoms (that is, SiH groups) in one molecule, and may be any of linear, branched, cyclic, or three-dimensional network-structured resinous substances. This organohydrogenpolysiloxane may have the number of silicon atoms (that is, the degree of polymerization) in one molecule usually being 2 to 300, preferably about 3 to 200. As representative examples of such organohydrogenpolysiloxanes, for example, organohydrogenpolysiloxanes represented by the following average composition formula (1) can be mentioned. H a R 3 b SiO (4-a-b) / 2 ···(1) (In the formula, R 3 are each independently an unsubstituted or substituted monovalent hydrocarbon group that does not contain an aliphatic unsaturated bond, and a and b are numbers such that 0 < a < 2, 0.8 ≤ b ≤ 2 and 0.8 < a + b ≤ 3, preferably 0.05 ≤ a ≤ 1, 1.5 ≤ b ≤ 2 and 1.8 ≤ a + b ≤ 2.7.)

[0030] The above R 3The monovalent hydrocarbon group not containing an aliphatic unsaturated bond preferably has 1 to 10 carbon atoms, and specific examples thereof include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl; cycloalkyl groups such as cyclopentyl, cyclohexyl, and cycloheptyl; aryl groups such as phenyl, tolyl, xylyl, naphthyl, and biphenylyl; aralkyl groups such as benzyl, phenylethyl, and phenylpropyl; and alkaryl groups such as methylbenzyl, as well as halogenated alkyl groups such as chloromethyl, 2-bromoethyl, 3-chloropropyl, and 3,3,3-trifluoropropyl, in which one or more hydrogen atoms of these hydrocarbon groups have been substituted with a halogen atom such as a fluorine atom, a chlorine atom, or a bromine atom, or a cyano group. Among these, those having 1 to 7 carbon atoms are preferred, and alkyl groups having 1 to 3 carbon atoms such as methyl groups, phenyl groups, and 3,3,3-trifluoropropyl groups are more preferred.

[0031] Specific examples of such organohydrogenpolysiloxanes include siloxane oligomers such as 1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane, 1,3,5,7,8-pentamethylcyclopentasiloxane, tris(dimethylhydrogensiloxy)methylsilane, and tris(dimethylhydrogensiloxy)phenylsilane; methylhydrogencyclopolysiloxane, methylhydrogensiloxane-dimethylsiloxane cyclic polysiloxanes; Copolymers, methylhydrogenpolysiloxanes terminated at both molecular chain ends with trimethylsiloxy groups, dimethylsiloxane-methylhydrogensiloxane copolymers terminated at both molecular chain ends with trimethylsiloxy groups, dimethylpolysiloxanes terminated at both molecular chain ends with dimethylhydrogensiloxy groups, methylhydrogenpolysiloxanes terminated at both molecular chain ends with dimethylhydrogensiloxy groups, dimethylsiloxane-methylhydrogensiloxane copolymers terminated at both molecular chain ends with dimethylhydrogensiloxy groups, etc.; R 3 2(H)SiO 1 / 2Units and SiO 4 / 2 units, and optionally R 3 3SiO 1 / 2 Units, R 3 2SiO 2 / 2 Units, R 3 (H)SiO 2 / 2 Units: (H)SiO 3 / 2 Unit or R 3 SiO 3 / 2 Silicone resins that may contain units (wherein R 3 has the same meaning as above.) and compounds in which some of the methyl groups in the above exemplary compounds have been substituted with other alkyl groups such as ethyl groups and n-propyl groups and / or phenyl groups.

[0032] The organohydrogenpolysiloxane used in the composition of the present invention can be obtained by a known method, for example, 3 SiHCl2 and R 3 2SiHCl (where R 3 has the same meaning as above.) or this chlorosilane and R 3 3SiCl and R 3 2SiCl2 (where R 3 has the same meaning as above.) The organohydrogenpolysiloxane used in the composition of the present invention may also be a product obtained by subjecting the polysiloxane obtained by such cohydrolysis to an equilibration reaction.

[0033] The amount of component (C) is such that the number of silicon-bonded hydrogen atoms (i.e., SiH groups) in the organohydrogenpolysiloxane of component (C) per silicon-bonded alkenyl group in the organopolysiloxanes of components (A) and (B) is 0.1 to 5.0, and preferably 0.2 to 2.0. The component (C) may be used alone or in combination of two or more types.

[0034] (D) Saturated aliphatic hydrocarbon compounds Component (D) is a saturated aliphatic hydrocarbon compound having 10 to 20 carbon atoms. As a dilution solvent, it improves coating workability, application properties with a spin coater, film thickness control, and the uniformity of the thickness and surface condition of the coating film. The saturated aliphatic hydrocarbon compound has 10 to 20 carbon atoms, preferably 12 to 16. If the number of carbon atoms is 21 or more, it is difficult to volatilize the compound during curing, and if the number of carbon atoms is less than 10, the rate of evaporation during application may be too fast, making it difficult to ensure smoothness.

[0035] Specific examples of component (D) include paraffinic or isoparaffinic solvents such as Pearleem (registered trademark) 3 and Pearleem 4 manufactured by NOF Corporation, Marukasol R manufactured by Maruzen Petrochemical Co., Ltd., and IP Solvent 1016 and IP Solvent 1620 manufactured by Idemitsu Kosan Co., Ltd.

[0036] The blend amount of component (D) is 1 to 10,000 parts by mass, preferably 10 to 5,000 parts by mass, per 100 parts by mass of component (A). Less than 1 part by mass will not be effective in suppressing variations in film thickness after coating, while more than 10,000 parts by mass may result in the film thickness after coating being too thin. The component (D) may be used alone or in combination of two or more types.

[0037] The composition of the present invention may contain an organic solvent other than component (D) as long as the effects of the present invention are not impaired. However, the amount of component (D) relative to the total mass of the solvent is preferably 90 mass% or more, and more preferably 100 mass%.

[0038] (E) Platinum group metal catalyst The platinum group metal catalyst of component (E) may be any catalyst that promotes the addition reaction between the alkenyl groups of components (A) and (B) and the Si-H groups of component (C), and any conventionally known catalyst may be used. Among these, catalysts selected from platinum and platinum compounds are preferred. Specific examples of the catalyst include platinum group metals such as platinum (including platinum black), rhodium, and palladium; platinum chlorides such as HPtCl4·nH2O, HPtCl6·H2O, NaHPtCl6·nH2O, KHPtCl6·nH2O, Na2PtCl6·nH2O, K2PtCl4·nH2O, PtCl4·nH2O, PtCl2, and Na2HPtCl4·nH2O (wherein n is an integer of 0 to 6, preferably 0 or 6), chloroplatinic acid, and chlorides. Examples include platinate salts, alcohol-modified chloroplatinic acid; complexes of chloroplatinic acid and olefins; platinum black, platinum group metals such as palladium supported on a support such as alumina, silica, or carbon; rhodium-olefin complexes, chlorotris(triphenylphosphine)rhodium (Wilkinson's catalyst); complexes of platinum chloride, chloroplatinic acid, or chloroplatinate salts with vinyl group-containing siloxanes, and the like. These may be used alone or in combination of two or more.

[0039] The amount of component (E) to be added should be an effective amount as a catalyst, and should be an amount that can promote the reaction between components (A) and (B) and component (C), and should be adjusted appropriately depending on the desired curing rate. In particular, an amount equivalent to 0.1 to 10,000 ppm, and more preferably 1 to 5,000 ppm, of platinum group metal atoms relative to the mass of component (A) is preferred. When the amount of component (E) is within the above range, more efficient catalytic action can be expected.

[0040] (F) Reaction inhibitor The composition of the present invention may contain a reaction inhibitor as component (F) for the purpose of suppressing the curing reaction at room temperature and extending the shelf life and pot life. Any reaction inhibitor that can suppress the catalytic activity of component (E) may be used, and any reaction inhibitor known in the art can be used. Specific examples thereof include acetylene alcohol compounds such as 1-ethynyl-1-cyclohexanol and 3-butyn-1-ol; various nitrogen compounds; organic phosphorus compounds; oxime compounds; organic chloro compounds; etc., which may be used alone or in combination of two or more. Among these, acetylene alcohol compounds that are not corrosive to metals are preferred.

[0041] When component (F) is used, the amount thereof is preferably 0.001 to 5 parts by mass, and more preferably 0.01 to 1 part by mass, per 100 parts by mass of component (A). If the amount of the reaction inhibitor is less than 0.001 part by mass, sufficient shelf life and pot life may not be obtained, while if it exceeds 5 parts by mass, the curability of the composition may decrease.

[0042] An antistatic agent may be added to the composition of the present invention for the purpose of reducing the surface resistivity and imparting antistatic properties to the material. Examples of antistatic agents include salts of alkali metals or alkaline earth metals, and ionic liquids. Here, the ionic liquid is a molten salt that is liquid at room temperature (25°C), also known as a room-temperature molten salt, and particularly refers to one with a melting point of 50°C or less, preferably -100 to 30°C, and more preferably -50 to 20°C. Such ionic liquids have properties such as no vapor pressure (non-volatility), high heat resistance, non-flammability, and chemical stability.

[0043] Examples of alkali metal or alkaline earth metal salts include alkali metal salts such as lithium, sodium, and potassium; alkaline earth metal salts such as calcium and barium. Specific examples of these include alkali metal salts such as LiClO4, LiCF3SO3, LiN(CF3SO2)2, LiAsF6, LiCl, NaSCN, KSCN, NaCl, NaI, and KI; and alkaline earth metal salts such as Ca(ClO4)2 and Ba(ClO4)2. Among these, lithium salts such as LiClO4, LiCF3SO3, LiN(CF3SO2)2, LiAsF6, and LiCl are preferred from the viewpoint of low resistance and solubility, and LiCF3SO3 and LiN(CF3SO2)2 are more preferred.

[0044] Ionic liquids consist of a quaternary ammonium cation and an anion. The quaternary ammonium cation can be imidazolium, pyridinium, or an anion of the formula: R 6 4N + [In the formula, R 6 are each independently a hydrogen atom or an organic group having 1 to 20 carbon atoms.]

[0045] Above R 6 Specific examples of the organic group represented by the formula include monovalent hydrocarbon groups having 1 to 20 carbon atoms, alkoxyalkyl groups, etc., and more specific examples include alkyl groups such as methyl, pentyl, hexyl, and heptyl groups; aryl groups such as phenyl, tolyl, xylyl, and naphthyl groups; aralkyl groups such as benzyl and phenethyl groups; cycloalkyl groups such as cyclopentyl, cyclohexyl, and cyclooctyl groups; and alkoxyalkyl groups such as ethoxyethyl group (-CH2CH2OCH2CH3). 6 Two of the organic groups represented by the formula (I) may be bonded to form a cyclic structure, in which case the two R 6 are combined to form a divalent organic group. The main chain of this divalent organic group may be composed of only carbon, or may contain heteroatoms such as oxygen atoms and nitrogen atoms. Specifically, for example, a divalent hydrocarbon group [for example, an alkylene group having 3 to 10 carbon atoms], a group represented by the formula: -(CH2) c -O-(CH2) d - [wherein c is an integer of 1 to 5, d is an integer of 1 to 5, and c+d is an integer of 4 to 10].

[0046] Above R 6 4N +Specific examples of the cation represented by the formula (I) include a methyltri-n-octylammonium cation, an ethoxyethylmethylpyrrolidinium cation, and an ethoxyethylmethylmorpholinium cation. The anion is not particularly limited, but for example, AlCl4 - , Al3Cl 10 - , Al2Cl7 - , ClO4 - , PF6 - , BF4 - , CF3SO3 - , (CF3SO2)2N - , (CF3SO2)3C - is preferred, and PF6 - , BF4 - , CF3SO3 - , (CF3SO2)2N - is more preferred.

[0047] When an antistatic agent is used, the amount added is preferably 0.001 to 10 parts by mass, and more preferably 0.005 to 10 parts by mass, per 100 parts by mass of the component (A) from the viewpoint of antistatic properties and heat resistance. The antistatic agents may be used singly or in combination of two or more.

[0048] The antistatic performance of the cured product obtained from the addition-curable silicone pressure-sensitive adhesive composition of the present invention containing an antistatic agent is measured by charging the surface of the cured product with 6 kV of static electricity by corona discharge using a Static Honest Meter (manufactured by Shishido Electrostatic Corporation), and the time it takes for the charged voltage to decrease by half (half-life) is preferably within 2 minutes, and more preferably within 1 minute.

[0049] The composition of the present invention may contain additives such as coloring materials (pigments or dyes), polymerization inhibitors, antioxidants, ultraviolet absorbers as light resistance stabilizers, and light stabilizers, as long as the effects of the present invention are not impaired. However, from the viewpoint of suppressing migration of materials onto elements, it is preferable that the composition does not contain a compound having an alkoxysilyl group as an adhesion-imparting component, a compound having an epoxy-containing group, or a compound having an alkenyl group other than components (A) and (B). The composition of the present invention can also be used by appropriately mixing it with other resin compositions.

[0050] The addition-curable silicone pressure-sensitive adhesive composition of the present invention can be obtained by mixing the above components (A) to (E), and, if necessary, other components, in any order, followed by stirring, etc. There are no particular restrictions on the steps for mixing and stirring the components. The composition may be in the form of either a one-component type or a two-component type, and a one-component type composition can be stored for a long period of time by refrigeration or freezing, while a two-component type composition can be stored for a long period of time at room temperature.

[0051] For example, a one-component composition containing components (A) to (F) can be obtained by placing components (A), (B), (D), and (E) in a Gate Mixer (manufactured by Inoue Seisakusho Co., Ltd., trade name: Planetary Mixer), mixing them at room temperature for 30 minutes, then adding component (F) and mixing them at room temperature for 30 minutes, and then adding component (C) and mixing them at room temperature for 30 minutes.

[0052] On the other hand, a two-component composition containing components (A) to (F) as a whole can be composed of any combination, as long as the combination of components (A), (C), and (E) and the combination of components (B), (C), and (E) are not the only components that coexist. For example, components (A), (B), (D), and (E) can be placed in a gate mixer and mixed under heat at room temperature for 30 minutes to obtain a composition called component A, and components (A), (C), and (F) can be placed in a gate mixer and mixed at room temperature for 30 minutes to obtain a composition called component B, to obtain a two-component composition of components A and B.

[0053] From the viewpoint of moldability and workability during application, the viscosity of the addition-curable silicone pressure-sensitive adhesive composition of the present invention, measured at 23°C using a rotational viscometer, is preferably 1,000 Pa·s or less, more preferably 500 Pa·s or less, and even more preferably 100 Pa·s or less. If the viscosity exceeds 1,000 Pa·s, workability may be significantly impaired.

[0054] The curing conditions for the addition-curable silicone pressure-sensitive adhesive composition of the present invention are not particularly limited and can be the same as those for known addition-curable silicone pressure-sensitive adhesive compositions. Curing can be carried out at room temperature or by heat, preferably at a temperature of 20 to 180°C, more preferably 50 to 150°C, for a period of preferably 0.1 to 3 hours, more preferably 0.5 to 2 hours.

[0055] In the present invention, the adhesive strength of the cured product is preferably 0.001 MPa or more, more preferably 0.005 MPa or more, in consideration of the balance between releasability and retention of the transferred material, and the upper limit thereof is preferably 1.0 MPa, more preferably 0.5 MPa, in consideration of the balance between releasability and retention of the transferred material. The addition-curable silicone pressure-sensitive adhesive composition of the present invention does not contain a non-crosslinkable organopolysiloxane resin, and the adhesive strength of the cured product is highly dependent on the amount of component (B), as previously mentioned.

[0056] In order to prevent cohesive failure during molding or transport of fine components such as elements, the cured product of the addition-curable silicone pressure-sensitive adhesive composition of the present invention preferably has a tensile strength (JIS-K6249:2003) of 0.3 MPa or more at a thickness of 2.0 mm, more preferably 0.5 MPa or more. There is no particular upper limit, but for the composition of the present invention, it is usually around 50 MPa.

[0057] The addition-curable silicone pressure-sensitive adhesive composition of the present invention can also be used as a pressure-sensitive adhesive article by applying it to various substrates and curing it. The substrate may be made of any material such as synthetic quartz, glass, plastic film, or metal, without any particular limitations. There are no particular limitations on the thickness or type of synthetic quartz or glass, and those that have been chemically strengthened may also be used. Examples of plastic films include polyethylene films, polypropylene films, polyester films, polyimide films, polyvinyl chloride films, polyvinylidene chloride films, polyvinyl alcohol films, polycarbonate films, polystyrene films, ethylene-vinyl acetate copolymer films, ethylene-vinyl alcohol copolymer films, and triacetyl cellulose films. In order to improve the adhesion between the substrate and the pressure-sensitive adhesive layer, the substrate may be previously subjected to a primer treatment, a plasma treatment, or the like.

[0058] The coating method can be appropriately selected from known coating methods such as a spin coater, comma coater, lip coater, roll coater, die coater, knife coater, blade coater, rod coater, kiss coater, gravure coater, screen coating, dip coating, and cast coating.

[0059] As shown in FIG. 1, the cured product of the addition-curable silicone pressure-sensitive adhesive composition of the present invention can be used as a support substrate 100 for transferring minute structures, for transferring minute elements, parts, and the like. 1, a support substrate 100 for transferring a microstructure is configured to have a cured layer 300 of the addition-curable silicone pressure-sensitive adhesive composition of the present invention on a substrate 200. In this case, the size of the cured layer 300 need only be such that it can be accommodated within the substrate 200, and it may even be exactly the same size as the substrate 200. There are no particular limitations on the material of the substrate 200, and specific examples include synthetic quartz, glass, plastic film, metal, etc. There are also no particular limitations on the thickness or type, and the substrate may be chemically strengthened. Note that in order to improve the adhesion between the substrate and the adhesive layer, the substrate may be previously subjected to a primer treatment, plasma treatment, etc. In order to suppress positional deviation during transfer of the microstructure and to increase transfer accuracy, it is preferable to use synthetic quartz, which has a high degree of flatness.

[0060] In the method of directly applying and curing an addition-curing silicone adhesive composition onto a substrate 200, the silicone adhesive composition is applied onto the substrate 200, and then cured by heat curing to obtain a support substrate 100 for transferring microstructures. The coating method can be appropriately selected from known coating methods such as a spin coater, comma coater, lip coater, roll coater, die coater, knife coater, blade coater, rod coater, kiss coater, gravure coater, screen coating, dip coating, and cast coating. Furthermore, by applying the silicone adhesive composition to a substrate using these methods and then curing it by heating on a hot plate or in an oven, a highly flat holding substrate 100 for transferring a microstructure can be obtained.

[0061] There are no particular restrictions on the thickness of the silicone pressure-sensitive adhesive composition to be applied, but it is preferable that the ratio of the applied film thickness to the thickness variation (the difference between the maximum film thickness and the minimum film thickness) be 0.03 or less, and more preferably 0.025 or less.

[0062] The above-described holding substrate for transferring a microstructure can be attached to a device and used as a microstructure transfer device. There are no restrictions on the method of attachment to the device, but examples include a vacuum chuck, an adhesive sheet, etc. The microstructure transfer device picks up a microstructure such as an element using the adhesiveness of the holding substrate for transferring a microstructure, moves it to the desired position, and then releases it, thereby achieving the transfer of the microstructure.

[0063] As a specific example of transferring a microstructure, the holding substrate 100 for transferring a microstructure of the present invention can be used as a holding substrate (donor substrate) for temporarily fixing a semiconductor element so as not to cause displacement during a laser lift-off (LLO) process in which a sapphire substrate of a semiconductor element is peeled off from a GaN-based compound crystal layer using laser light. In this case, it is preferable to use synthetic quartz with high flatness as the base material 200.

[0064] Furthermore, in order to selectively pick up the semiconductor element temporarily fixed on the holding substrate, a holding substrate (stamp) 100 for transferring a microstructure, which has a stronger adhesive force than the holding substrate, can be used. After the picked-up semiconductor element is moved to a desired position on the mounting substrate, soldering is performed to bond the semiconductor element to the mounting substrate, and the holding substrate for transferring the microstructure is peeled off from the semiconductor element, thereby achieving transfer of the semiconductor element and mounting on the substrate.

[0065] Considering the balance between releasability and holding ability of the transferred material, the adhesive strength of the cured material layer 300 on the holding substrate is preferably 0.001 to 2 MPa, more preferably 0.002 to 1 MPa. The adhesive strength of the cured material layer 300 on the microstructure transfer stamp is preferably greater than the adhesive strength of the holding substrate, and is preferably 0.01 MPa or more, more preferably 0.1 MPa or more. [Example]

[0066] The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. The compounds used for each component are as follows:

[0067] Component (A) (A-1) An organopolysiloxane having a viscosity of 5 Pa·s at 25°C and represented by the following formula: [ka]

[0068] (A-2) An organopolysiloxane having a viscosity of 100 Pa·s at 25°C, represented by the following formula: [ka]

[0069] (B) Component (B-1)Me3SiO 1 / 2 :Me2ViSiO 1 / 2 :SiO 4 / 2 Organopolysiloxane resin (weight average molecular weight 5,300, Si-Vis content 0.085 mol / 100 g) expressed in a ratio of 0.35:0.10:0.55

[0070] (C) Component (C-1) Organohydrogensiloxane represented by the following formula: [ka]

[0071] (C-2) Organohydrogensiloxane represented by the following formula: [ka] (In the formula, the arrangement order of the siloxane units in the parentheses is random or block.)

[0072] (D) Component (D-1) Pearleem 4 (NOF Corporation; isoparaffin solvent with 13 to 16 carbon atoms; CAS No. 68551-20-2) (D-2) Marukasol R (Maruzen Petrochemical Co., Ltd.; isododecane with 12 carbon atoms; CAS No. 13475-82-6) (D-3) Xylene

[0073] (E) Component (E-1) Dimethylpolysiloxane solution of platinum-divinyltetramethyldisiloxane complex (both ends are capped with dimethylvinylsilyl groups, and the complex is dissolved in dimethylpolysiloxane with a viscosity of 0.6 Pa·s at 25°C. It contains 1% by mass of platinum atoms.)

[0074] (F) Component (F-1) 1-ethynyl-1-cyclohexanol

[0075] [Examples 1 to 10 and Comparative Examples 1 and 2] Components (A), (B), (D), (E), and (F) were added to a gate mixer (5L planetary mixer manufactured by Inoue Seisakusho Co., Ltd.) in the amounts shown in Table 1 and mixed at room temperature for 30 minutes. Next, component (G) was added in the amount shown in Tables 1 and 2 and mixed at room temperature for 30 minutes. Finally, component (C) was added in the amount shown in Table 1 and mixed at 25°C for 30 minutes until uniform. The physical properties of each of the resulting compositions were measured using the methods described below. The results are also shown in Tables 1 and 2. The viscosity of the compositions in Tables 1 and 2 was measured at 23°C using a rotational viscometer.

[0076] [Measurement of physical properties of cured product] The prepared composition was press-cured at 150°C for 10 minutes and then heated in an oven at 150°C for 30 minutes. The sheet thickness was 2.0 mm. The hardness, tensile strength, and elongation at break of the cured product were measured in accordance with JIS-K6249:2003. The adhesiveness of the cured product was measured using a small benchtop tester EZ-SX manufactured by Shimadzu Corporation. Specifically, a 1 mm square stainless steel probe was pressed against a 1 mm thick cured product at 1 MPa for 15 seconds, and then the load applied when the probe was pulled at a speed of 200 mm / min was measured.

[0077] [Spin ​​coating film thickness] The prepared composition was applied to a 6-inch synthetic quartz substrate using a spin coater (Mikasa Co., Ltd.) at room temperature under spin conditions of 3000 rpm / 2 minutes. After curing on a hot plate at 150°C / 5 minutes, it was post-cured in an oven at 150°C / 30 minutes. Then, using a film thickness measuring device (Filmetrics Co., Ltd.) using optical interferometry, the film thickness was measured at 49 points along the diameter, and the average value was recorded as the film thickness (note that measurements were taken within 2 mm of the innermost area to avoid the influence of the silicone layer edge). The difference between the maximum and minimum film thicknesses of the 49 points was recorded as the thickness variation.

[0078] [Table 1]

[0079] [Table 2]

[0080] As shown in Tables 1 and 2, the addition-curable silicone pressure-sensitive adhesive compositions prepared in Examples 1 to 10 can be applied smoothly to substrates with little variation in thickness. Furthermore, the cured products have excellent adhesiveness and tensile strength, making them useful as temporary fixing materials for transporting fine components such as elements. On the other hand, Comparative Example 1, which does not contain the component (D) of the present invention, exhibits large thickness variations and insufficient smoothness, and Comparative Example 2, which uses a composition in which the component (D) is changed to xylene, an aromatic hydrocarbon solvent having 8 carbon atoms, also exhibits large thickness variations and insufficient smoothness. [Explanation of symbols]

[0081] 100 Holding substrate for microstructure transfer 200 Base material 300 Cured material layer

Claims

1. (A) a linear organopolysiloxane having at least two silicon-bonded alkenyl groups per molecule: 100 parts by mass, (B) organopolysiloxane resin having an alkenyl group: 5 to 500 parts by mass, (C) an organohydrogenpolysiloxane having two or more silicon-bonded hydrogen atoms per molecule: an amount such that the number of silicon-bonded hydrogen atoms in component (C) is 0.1 to 5.0 times the molar amount of all silicon-bonded alkenyl groups in the composition; (D) saturated aliphatic hydrocarbon compound having 10 to 20 carbon atoms: 1 to 10,000 parts by mass, and, (E) Platinum group metal catalyst and an addition-curable silicone pressure-sensitive adhesive composition containing no non-crosslinkable organopolysiloxane.

2. 2. The addition-curable silicone pressure-sensitive adhesive composition according to claim 1, further comprising 0.01 to 5.0 parts by mass of a reaction inhibitor (F) per 100 parts by mass of component (A).

3. 2. The addition-curable silicone pressure-sensitive adhesive composition of claim 1, which does not contain any compound having an alkoxysilyl group, any compound having an epoxy-containing group, or any compound having an alkenyl group other than components (A) and (B).

4. A cured silicone product obtained by curing the addition-curable silicone pressure-sensitive adhesive composition according to any one of claims 1 to 3.

5. The silicone cured product according to claim 4, which has an adhesive strength of at least 0.001 MPa.

6. 5. The silicone cured product according to claim 4, which has a tensile strength of at least 0.3 MPa.

7. A pressure-sensitive adhesive comprising the silicone cured product according to claim 4.

8. A pressure-sensitive adhesive sheet comprising the silicone cured product according to claim 4.

9. A microstructure-holding substrate having an adhesive layer made of the silicone cured product according to claim 4.

10. A microstructure transfer device comprising the microstructure holding substrate according to claim 9.

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