ORGANOPOLYSILOXANE AND ROOM-TEMPERATURE-CURABLE ORGANOPOLYSILOXANE COMPOSITION CONTAINING THE SAME

Abstract

An organopolysiloxane according to the present invention, having a structural unit ratio represented by formula (1), provides a room temperature-curable composition that has excellent curability and stability even when a solvent is not used, and that is capable of producing a cured product having high hardness and high transparency. (R1 and R2 each represent an alkyl group having 1-12 carbon atoms or an aryl group having 6-10 carbon atoms; k represents an integer of 1-3; m represents a number of 5-100; n represents 2 or 3; R3, R4, and R5 each represent an alkyl group having 1-12 carbon atoms, an alkenyl group having 2-8 carbon atoms, an aryl group having 6-10 carbon atoms, an aralkyl group having 7-10 carbon atoms, an alkoxy group having 1-4 carbon atoms, or a hydroxy group; and a, b, c, d, e, and f each represent a number satisfying a > 0, b > 0, c ≥ 0, d > 0, e > 0, and f ≥ 0, as well as a+b+c+d+e+f = 1.)

Description

[Technical Field]

[0001] The present invention relates to an organopolysiloxane and a room-temperature-curable organopolysiloxane composition containing the same. [Background technology]

[0002] Room-temperature-curable organopolysiloxane compositions, which can cure at room temperature by reacting with moisture in the air, do not require heat or special equipment for curing and are therefore widely used as sealants, adhesives, or coatings for electrical or electronic devices. Among these, room-temperature-curable organopolysiloxane compositions of the dealcohol-free or acetone-free type are commonly used for sealants for electrical or electronic devices. These solvent-free room-temperature-curable organopolysiloxane compositions have the advantages of being less corrosive to metals, reducing the risk of corrosion of electrodes or wiring, and also providing excellent adhesion.

[0003] In particular, conformal coatings applied to protect the surfaces of electrical and electronic components and circuit boards carrying them from the environment in which they are used comprise coatings made from low-viscosity, room-temperature-curable polyorganosiloxane compositions. In these coatings, a cured film is formed by the condensation reaction of a linear organopolysiloxane with a crosslinkable low-molecular-weight siloxane.

[0004] However, such cured films of linear organopolysiloxanes and crosslinkable low-molecular-weight siloxanes have problems such as low hardness and vulnerability to scratches. Various studies have been conducted to solve this problem (Patent Documents 1 and 2), but the hardness of the films remains insufficient. Furthermore, since the above composition involves mixing and crosslinking multiple components, there is also the problem that the coating film whitens as the crosslinking of the linear organopolysiloxane progresses (Patent Document 3).

[0005] In the field of coatings, alkoxysilicone resin oligomers are often used to create high-hardness films, but because a solvent is generally required to dissolve the organopolysiloxane, when used as a conformal coating agent, there is a risk of the solvent evaporating, which can cause work-related problems and corrosion of electrodes and wiring. Furthermore, with typical alkoxysilicone resin oligomers, the highly reactive condensation sites react during synthesis, so there are no highly reactive condensation sites remaining in the final organopolysiloxane product, which creates the problem of the coating taking a long time to harden due to the condensation reaction.

[0006] Furthermore, alkoxysilicone resin oligomers that form high-hardness coatings lack flexibility and flex resistance due to their high crosslink density, and they face the problem of cracks forming in the coating over time after formation or when external stress is applied. To improve the flexibility and flex resistance of these high-hardness coatings, methods have been developed to incorporate diorganosiloxane units (D units), such as by using diorganodialkoxysilanes in combination during synthesis by hydrolysis condensation, or to introduce consecutive D units by hydrosilylation, into alkoxysilicone oligomers (Patent Document 4).

[0007] Alkoxysilicone oligomers in which successive D units have been introduced by hydrosilylation allow for the D units to be introduced locally compared to methods using random hydrolysis and condensation, making it easier to develop the properties of diorganopolysiloxanes. However, the hydrolysis of the alkoxysilyl moieties also decreases, as described above, and improvements in curability are needed. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 5763284 [Patent Document 2] Patent No. 6964472 [Patent Document 3] Special Publication No. 2021-517188 [Patent Document 4] Patent No. 6642324 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has been made in view of the above circumstances, and has as its object to provide an organopolysiloxane that provides a room-temperature-curable composition that has excellent curability and stability even in the absence of a solvent, and that is capable of producing a cured product having high hardness and high transparency, and a room-temperature-curable organopolysiloxane composition containing the same. [Means for solving the problem]

[0010] As a result of extensive research conducted by the present inventors in order to achieve the above object, they discovered that a curable composition containing an organopolysiloxane having a specific polydimethylsiloxane-containing unit can be cured at room temperature, has excellent stability, and gives a cured product having high hardness and high transparency, and thus completed the present invention.

[0011] That is, the present invention is 1. An organopolysiloxane having a structural unit ratio represented by the following formula (1): [ka] (In the formula, R 1 and R 2 each independently represents an unsubstituted or substituted alkyl group having 1 to 12 carbon atoms or an unsubstituted or substituted aryl group having 6 to 10 carbon atoms; k represents an integer of 1 to 3; m represents a number of 5 to 100; n represents 2 or 3; R 3 , R 4 and R 5each independently represents an unsubstituted or substituted alkyl group having 1 to 12 carbon atoms, an unsubstituted or substituted alkenyl group having 2 to 8 carbon atoms, an unsubstituted or substituted aryl group having 6 to 10 carbon atoms, an unsubstituted or substituted aralkyl group having 7 to 10 carbon atoms, an unsubstituted or substituted alkoxy group having 1 to 4 carbon atoms, or a hydroxy group, and a, b, c, d, e, and f represent numbers that satisfy a>0, b>0, c≧0, d>0, e>0, f≧0, and a+b+c+d+e+f=1. 2. The above R 1 and R 2 each independently represents a methyl group or an ethyl group; 3. Kinematic viscosity at 25°C is 100 to 2,000 mm 2 1 or 2 organopolysiloxanes, 4. The organopolysiloxane of any one of 1 to 3, having a weight average molecular weight (Mw) of 1,000 to 50,000 in terms of polystyrene as determined by gel permeation chromatography. 5. (A) 100 parts by mass of any one of the organopolysiloxanes 1 to 4, and (B) Condensation reaction catalyst: 0.1 to 15 parts by mass a room-temperature-curable organopolysiloxane composition comprising: 6. The room-temperature-curable organopolysiloxane composition of 5, wherein the component (B) contains an organotitanium compound. 7. The room-temperature-curable organopolysiloxane composition of 5 or 6, which contains (C) a silane compound represented by the following general formula (2) in an amount of 0.5 to 50 parts by mass per 100 parts by mass of component (A): R 6 g Si(OR 7 ) 4-g (2) (In the formula, R 6 each independently represents an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, or an acyl group having 2 to 8 carbon atoms; R 7represents an alkyl group having 1 to 8 carbon atoms or an acyl group having 2 to 8 carbon atoms, and g represents an integer of 0 to 3. 8. The room-temperature-curable organopolysiloxane composition of any one of 5 to 7, wherein the solvent content is 1 mass% or less based on the total composition. 9. An electric or electronic part sealed, fixed or bonded with a cured product of the room-temperature-curable organopolysiloxane composition according to any one of 5 to 8. 10. A conformal coating comprising the room-temperature-curable organopolysiloxane composition of any one of 5 to 8. to provide. [Effects of the Invention]

[0012] The organopolysiloxane of the present invention provides a room temperature curable composition that has low viscosity, excellent coatability, and excellent curability and stability even without the use of a solvent. Furthermore, the cured products obtained from the curable compositions containing the organopolysiloxanes of the present invention have high hardness and excellent transparency, making them useful as coating materials (conformal coatings) for electrical or electronic devices, potting materials, and the like. DETAILED DESCRIPTION OF THE INVENTION

[0013] The present invention will be specifically described below. [1] Organopolysiloxane The organopolysiloxane of the present invention has a ratio of constituent units represented by the following formula (1).

[0014] [ka]

[0015] Above R 1 and R 2 each independently represents an unsubstituted or substituted alkyl group having 1 to 12 carbon atoms, or an unsubstituted or substituted aryl group having 6 to 10 carbon atoms. Specific examples of alkyl groups having 1 to 12 carbon atoms include methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, n-pentyl, n-hexyl, n-heptyl, and n-octyl groups. Specific examples of the aryl group having 6 to 12 carbon atoms include phenyl and naphthyl groups. In addition, some or all of the hydrogen atoms in the C-H bonds of these substituents may be substituted with halogen atoms such as chlorine, fluorine, or bromine, and an example thereof is a 1,1,1-trifluoropropyl group (trifluoromethylethyl group) in which the 1-position of a propyl group is substituted with a fluorine atom.

[0016] Among these, R 1 and R 2 As the alkyl group, methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, phenyl, benzyl, and vinyl groups are preferred, and methyl, ethyl, and phenyl groups are more preferred.

[0017] R 3 , R 4 and R 5 each independently represents an unsubstituted or substituted alkyl group having 1 to 12 carbon atoms, an unsubstituted or substituted alkenyl group having 2 to 8 carbon atoms, an unsubstituted or substituted aryl group having 6 to 10 carbon atoms, an unsubstituted or substituted aralkyl group having 7 to 10 carbon atoms, an unsubstituted or substituted alkoxy group having 1 to 4 carbon atoms, or a hydroxy group. Specific examples of alkyl groups having 1 to 12 carbon atoms include methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, n-pentyl, n-hexyl, n-heptyl, and n-octyl groups. Specific examples of the alkenyl group having 2 to 12 carbon atoms include vinyl, allyl, 3-butenyl, 5-hexenyl, 7-octenyl, 9-decenyl, and 11-dodecenyl groups. Specific examples of the aryl group having 6 to 12 carbon atoms include phenyl and naphthyl groups. Specific examples of the aralkyl group having 7 to 12 carbon atoms include benzyl, phenylethyl group, and the like. Specific examples of the alkoxy group having 1 to 4 carbon atoms include methoxy, ethoxy, propoxy, n-butoxy, i-butoxy group, and the like.

[0018] In addition, in the C—H bond of these substituents, some or all of the hydrogen atoms may be substituted with halogen atoms such as chlorine, fluorine, bromine, etc. As an example thereof, there may be mentioned a 1,1,1-trifluoropropyl group (trifluoromethylethyl group) in which the 1-position of the propyl group is substituted with a fluorine atom, and the like.

[0019] Among these, R 3 、R 4 and R 5 are preferably a methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, phenyl, benzyl, vinyl group, and more preferably a methyl, ethyl, phenyl, vinyl group.

[0020] k is an integer of 1 to 3, and preferably 3. m is a number of 5 to 100, preferably 5 to 50, more preferably 5 to 30. n is 2 or 3.

[0021] a>0, b>0, c≧0, d>0, e>0, f≧0, and is a number satisfying a + b + c + d + e + f = 1. a is a number satisfying a>0, but from the viewpoints of the hardness and curability of the obtained cured film, 0.01 <a≦0.5 is preferable, and 0.01≦a≦0.2 is more preferable. b is a number satisfying b>0, but from the viewpoint of the hardness of the obtained cured film, 0.01≦b≦0.5 is preferable, and 0.01≦b≦0.3 is more preferable. c is a number satisfying c≧0, but from the viewpoints of the curability of the composition and the hardness of the obtained cured film, 0≦c≦0.4 is preferable, 0≦c≦0.3 is more preferable, and 0 is even more preferable. d is a number satisfying d > 0. From the viewpoints of the curability of the composition and the hardness of the resulting cured film, 0 < d ≤ 0.8 is preferable, and 0.1 ≤ d ≤ 0.6 is more preferable. e is a number not satisfying e > 0. From the viewpoints of the curability of the composition and the hardness of the resulting cured film, 0.1 ≤ e ≤ 0.8 is preferable, and 0.1 ≤ e ≤ 0.6 is more preferable. f is a number satisfying f ≥ 0. From the viewpoints of the curability of the composition and the hardness of the resulting cured film, 0 ≤ f ≤ 0.5 is preferable, and 0.01 ≤ f ≤ 0.2 is more preferable. Also, a + b is preferably a number satisfying 0.02 ≤ (a + b) ≤ 0.4, and more preferably 0.02 ≤ (a + b) ≤ 0.1.

[0022] The organopolysiloxane having the structural unit ratio represented by the above formula (1) can be produced according to a method by general hydrolysis condensation and hydrosilylation. For example, an oligomer (c1) obtained by hydrolysis condensation of a monomer containing a silane compound having a hydrolyzable group such as an alkenyl group and an alkoxysilyl group is subjected to a hydrosilylation reaction with a linear organohydrogenpolysiloxane (a1) having a Si-H group at one end and an alkoxysilyl group at the other end, and a linear organohydrogenpolysiloxane (b1) having SiH groups at both ends. The reactivity on the coating film of the resulting organopolysiloxane is insufficient only with the linear organohydrogenpolysiloxane (b1) having Si-H groups at both ends, and the molecular weight of the organopolysiloxane decreases and the film-forming property deteriorates only with the linear organohydrogenpolysiloxane (a1) having a Si-H group at one end and an alkoxysilyl group at the other end. In addition, an organic solvent may be used during the hydrolysis condensation. Specific examples of the organic solvent that can be used include methanol, ethanol, propanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, toluene, xylene, and the like.

[0023] The molar ratio of (b1) to (a1) is preferably (b1) / (a1)=0.2 to 10, more preferably 1 to 4, from the viewpoint of film-forming properties and reactivity. In order to prevent unreacted organohydrogenpolysiloxane from remaining, the ratio of the total number of Si-H groups contained in the organohydrogenpolysiloxanes (a1) and (b1) to the number of alkenyl groups contained in the oligomer (c1) (number of alkenyl groups) / (number of Si-H groups) is preferably in the range of 1.1 to 10, more preferably 1.2 to 5.

[0024] The kinematic viscosity of the organopolysiloxane of the present invention at 25°C is 100 to 2,000 mm 2 / s is preferable, 300 to 500 mm 2 The kinematic viscosity is a value measured at 25°C using a Cannon-Fenske viscometer according to the method described in JIS Z 8803:2011 (the same applies hereinafter). The organopolysiloxane of the present invention preferably has a weight average molecular weight (Mw) of 1,000 to 50,000, more preferably 5,000 to 20,000, as measured by gel permeation chromatography (GPC) in terms of polystyrene.

[0025] [2] Room temperature curable organopolysiloxane composition The room-temperature-curable organopolysiloxane composition of the present invention comprises the following components (A) and (B): (A) Organopolysiloxane having the structural unit ratio represented by the above formula (1): 100 parts by mass (B) Condensation reaction catalyst: 0.1 to 15 parts by mass In the present invention, "room temperature" means a temperature at which neither heating nor cooling is carried out, and generally means a temperature range of 0 to 40°C, preferably 5 to 35°C.

[0026] The condensation reaction catalyst of component (B) is not particularly limited as long as it is one that is commonly used in organosiloxane-based paints, but organometallic compounds are preferred, such as metal alkoxide compounds of Ti, Al, Zr, Sn, etc., metal chelate compounds, and metal ester compounds.

[0027] Specific examples of the metal alkoxide compound include aluminum alkoxides such as aluminum trimethoxide, aluminum triethoxide, aluminum tri-n-propoxide, aluminum triisopropoxide, aluminum tri-n-butoxide, aluminum triisobutoxide, aluminum tri-s-butoxide, and aluminum tri-t-butoxide; tetramethyl titanate, tetraethyl titanate, tetra-n-propyl titanate, tetraisopropyl titanate, tetra-n-butyl titanate, tetraisobutyl titanate, tetra-t-butyl titanate, and tetra-n-hexyl titanate. titanium alkoxides such as tetraethyl zirconate, tetra-n-propyl zirconate, tetraisopropyl zirconate, tetra-n-butyl zirconate, tetra-s-butyl zirconate, tetra-t-butyl zirconate, tetra-n-pentyl zirconate, tetra-t-pentyl zirconate, tetra-t-hexyl zirconate, tetra-n-heptyl zirconate, tetra-n-octyl zirconate, tetra-n-stearyl zirconate, and the like; and dibutyltin dibutoxide.

[0028] Specific examples of metal chelate compounds include tris(ethylacetoacetate)aluminum, tris(n-propylacetoacetate)aluminum, tris(isopropylacetoacetate)aluminum, tris(n-butylacetoacetate)aluminum, isopropoxybis(ethylacetoacetate)aluminum, tris(acetylacetonato)aluminum, tris(propionylacetonato)aluminum, diisopropoxypropionylacetonatoaluminum, acetylacetonatobis(propionylacetonato)aluminum, monoethylacetoacetatebis(acetylacetonato)aluminum, acetylacetonatoaluminumdi-s-butylate, methylacetoacetatealuminumdi-s-butylate, di(methylacetoacetate)aluminummono-tert-butylate, diisopropoxyethylacetonatoaluminum, Examples of suitable chelate compounds include aluminum chelate compounds such as aluminum acetoacetate and monoacetylacetonato bis(ethylacetoacetate)aluminum; titanium chelate compounds such as diisopropoxy bis(ethylacetoacetate)titanate, diisopropoxy bis(acetylacetonato)titanate, and di-n-butoxy bis(acetylacetonato)titanate; zirconium chelate compounds such as tetrakis(acetylacetonato)zirconium, tetrakis(n-propylacetoacetate)zirconium, and tetrakis(ethylacetoacetate)zirconium; and tin chelate compounds such as tin ester compounds such as dibutyltin diacetate, dibutyltin di(2-ethylhexyl)ate, dibenzyltin di(2-ethylhexyl)ate, dibutyltin dilaurate, dibutyltin diisooctylmaleate, and dibutyltin bis(acetylacetonate).

[0029] Among these, catalysts for condensation reactions are preferably those containing organic titanium compounds such as titanium alkoxide compounds and titanium chelate compounds, more preferably those containing titanium chelate compounds from the viewpoint of the reaction activity and stability of the composition, and even more preferably those containing only titanium chelate compounds. Commercially available titanium chelate compounds can also be used, such as D-20, D-25, and D-26 (all manufactured by Shin-Etsu Chemical Co., Ltd.), Orgatix TC-750, and Orgatix TC-401 (manufactured by Matsumoto Fine Chemical Co., Ltd.).

[0030] The amount of component (B) blended is 0.1 to 15 parts by mass, preferably 0.5 to 5 parts by mass, per 100 parts by mass of component (A). If the amount of component (B) is less than the above range, the reactivity and hardness of the resulting composition will be insufficient, while if it is too much, the stability will be insufficient. The component (B) may be used alone or in combination of two or more types.

[0031] In addition to the above components (A) and (B), the room-temperature-curable organopolysiloxane composition of the present invention may also contain a silane compound represented by the following formula (2) as component (C). R 6 g Si(OR 7 ) 4-g (2)

[0032] In the formula, R 6 each independently represents an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, or an acyl group having 2 to 8 carbon atoms. Specific examples of alkyl groups having 1 to 8 carbon atoms include methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, n-pentyl, n-hexyl, n-heptyl, and n-octyl groups. Specific examples of the alkenyl group having 2 to 8 carbon atoms include vinyl, allyl, 3-butenyl, 5-hexenyl, and 7-octenyl groups. Specific examples of the aryl group having 6 to 10 carbon atoms include phenyl and naphthyl groups. Specific examples of the aralkyl group having 7 to 10 carbon atoms include benzyl and phenylethyl groups. Specific examples of the acyl group having 2 to 8 carbon atoms include an acetyl group and a propionyl group. Among these, R 6 As the alkyl group, a methyl group and a phenyl group are preferred.

[0033] R 7 represents an alkyl group having 1 to 8 carbon atoms or an acyl group having 2 to 8 carbon atoms. Specific examples of alkyl groups having 1 to 8 carbon atoms include methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, n-pentyl, n-hexyl, n-heptyl, and n-octyl groups. Specific examples of the acyl group having 2 to 8 carbon atoms include an acetyl group and a propionyl group. Among these, R 7 As the alkyl group, a methyl group and an ethyl group are preferred.

[0034] g is an integer of 0 to 3, and is preferably 1 or 2.

[0035] Specific examples of component (C) include, but are not limited to, dimethyldimethoxysilane, methyltrimethoxysilane, methylphenyldimethoxysilane, dimethyldiethoxysilane, and vinyltrimethoxysilane. The component (C) may be used alone or in combination of two or more types.

[0036] When component (C) is used, its content is preferably 0.5 to 50 parts by mass, more preferably 1 to 20 parts by mass, per 100 parts by mass of component (A). When the content of component (C) is at least the lower limit of the above range, the resulting composition cures more quickly due to moisture in the air, and when the content is at most the upper limit of the above range, there is no risk of poor appearance or reduced hardness of the cured product.

[0037] In addition to the above components (a) to (C), the room-temperature-curable organopolysiloxane composition of the present invention may contain any suitable additives as long as the effects of the present invention are not impaired. Specific examples of the additives include adhesion promoters such as non-reactive silicone oil, reactive silicone oil, and silane coupling agents, non-reactive polymer resins, fillers, leveling agents, rheology modifiers, reactive diluents, non-reactive diluents, surfactants, dispersants, antifoaming agents, dehydrating agents, antioxidants, antioxidants, antistatic agents, infrared absorbers, ultraviolet absorbers, light stabilizers, fluorescent agents, dyes, pigments, fragrances, abrasives, rust inhibitors, and thixotropy-imparting agents. These may be used alone or in combination of two or more.

[0038] The room-temperature-curable organopolysiloxane composition of the present invention is preferably a solvent-free form that contains substantially no solvent, but a solvent can also be added depending on the intended use and workability. Here, "substantially" means that the solvent content in the composition is 1% by mass or less, and particularly 0.1% by mass or less. Within this range, no solvent removal step is required during the formation of the cured coating, and solvent evaporation does not deteriorate the working environment or cause corrosion or deterioration of electrical and electronic components or the circuit boards on which they are mounted. Specific examples of solvents that can be used include the same reaction solvents used in the production of the organopolysiloxane of component (A). Note that this also includes solvents that were not intentionally added to the composition, such as reaction solvents that could not be completely removed by vacuum distillation.

[0039] The room-temperature-curable organopolysiloxane composition of the present invention can be obtained by mixing the above-mentioned components (A) and (B), as well as other components such as component (C) and optional additives, which are blended as needed, in a moisture-protected state.

[0040] The kinematic viscosity of the room-temperature-curable organopolysiloxane composition of the present invention is 50 to 1000 mm at 25°C. 2 / s is preferable, 100 to 500 mm 2 Within this range, the coating properties are good and the composition can be applied by a normal coating method without diluting it with a solvent. The coating of the room-temperature-curable organopolysiloxane composition of the present invention rapidly cures at room temperature upon contact with moisture in the air to form a coating, which preferably has a Type A hardness of 90 or greater according to JIS K6249.

[0041] The room-temperature-curable organopolysiloxane composition of the present invention can be stored as is in a sealed container and can be used as a so-called one-package room-temperature-curable composition that cures only upon exposure to moisture in the air at the time of use. The room-temperature-curable organopolysiloxane composition can also be used as a so-called multi-package room-temperature-curable composition, in which, for example, components (A) and (C) and component (B) are stored separately in two or three separate containers and mixed at the time of use. The order in which the components are mixed is not particularly limited. [Example]

[0042] 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.

[0043] In the examples, the kinematic viscosity was measured at 25°C using a Cannon-Fenske viscometer according to the method described in JIS Z 8803:2011. The molecular weight was determined as a weight average molecular weight in terms of polystyrene by measurement using a GPC (gel permeation chromatograph) device manufactured by Tosoh Corporation, using toluene as a solvent and RI as a detector. The ratio of the constituent units of the organopolysiloxane was measured using a 300 MHz NMR measurement device manufactured by JEOL Ltd. 1 H-NMR and 29 It was calculated from the integral value of the detected spectrum in Si-NMR. The vinyl group content (mol / 100 g, hereinafter referred to as the vinyl value) was determined by treating each product with Hanus's solution, then reacting it with an aqueous potassium iodide solution, and titrating the resulting iodine with sodium thiosulfate.

[0044] [1] Production of organopolysiloxane [Synthesis Example 1] A 500 mL separable flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer was charged with 185 g (1.54 mol) of methyltrimethoxysilane, 40 g (0.27 mol) of vinylmethyldimethoxysilane, and 0.07 g of maleic anhydride. 34.7 g of ion-exchanged water was added dropwise with stirring at 15°C, and the reaction was carried out at 70°C for 3 hours. 6 g of cation exchange resin (Lewatit K2629, manufactured by LANXESS) was then added, and the reaction was carried out at 70°C for an additional 3 hours. The resulting reaction solution was distilled under atmospheric pressure, and once no more distillate was produced, it was heated at 105°C for 3 hours. Finally, the distillate was removed under reduced pressure (90°C, 1.3 kPa), yielding organopolysiloxane (A-0) (yield: 145 g). The resulting organopolysiloxane (A-0) was a colorless, transparent liquid with a kinematic viscosity of 66 mmHg. 2 The copolymer had a vinyl number of 0.15 mol / 100 g, a molecular weight of 3,100, and a vinyl number of 0.15 mol / 100 g. The structural unit ratios in formula (1) were a = 0, b = 0, c = 0, d = 0.40, e = 0.58, and f = 0.02.

[0045] [Example 1-1] A 3-L separable flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer was charged with 750 g of the organopolysiloxane (A-0) obtained in Synthesis Example 1, 325 g of an organohydrogenpolysiloxane represented by the following formula (3), and 310 g of an organohydrogenpolysiloxane represented by the following formula (4). The resulting mixture was mixed. The vinyl group to Si-H group reaction molar ratio was 4:1. While stirring at 80°C, 0.0004 moles of a 1,3-divinyltetramethyldisiloxane complex of Pt(0) was added per mole of Si-H group, and the reaction was carried out at 80°C for 3 hours. The fraction was then removed by vacuum distillation (90°C, 1.3 kPa), yielding organopolysiloxane (A-1) (yield: 1,350 g). The resulting organopolysiloxane (A-1) was a colorless, transparent liquid with a kinematic viscosity of 300 mm 2 The ratio of the structural units in formula (1) was a=0.01, b=0.01, c=0, d=0.43, e=0.53, and f=0.02.

[0046] [ka]

[0047] [Example 1-2] A 3-L separable flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer was charged with 750 g of the organopolysiloxane (A-0) obtained in Synthesis Example 1, 320 g of the organohydrogenpolysiloxane represented by the following formula (5), and 310 g of the organohydrogenpolysiloxane represented by the above formula (4). The resulting mixture was mixed. The vinyl group to Si-H group reaction molar ratio was 4:1. While stirring at 80°C, 0.0004 moles of Pt(0) 1,3-divinyltetramethyldisiloxane complex was added per mole of Si-H group, and the reaction was carried out at 80°C for 3 hours. The fraction was then removed by vacuum distillation (90°C, 1.3 kPa), yielding organopolysiloxane (A-2) (yield: 1,300 g). The resulting organopolysiloxane (A-2) was a colorless, transparent liquid with a kinematic viscosity of 320 mm 2 The ratio of the structural units in formula (1) was a=0.01, b=0.01, c=0, d=0.43, e=0.53, and f=0.02.

[0048] [ka]

[0049] [Examples 1-3] 750 g of the organopolysiloxane (A-0) obtained in Synthesis Example 1, 150 g of an organohydrogenpolysiloxane represented by the following formula (6), and 120 g of an organohydrogenpolysiloxane represented by the following formula (7) were mixed in a 3-L separable flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer. The reaction molar ratio of vinyl groups to Si-H groups was 2:1. While stirring at 80°C, 1,3-divinyltetramethyldisiloxane complex of Pt(0) was added in an amount of 0.0004 mole per mole of Si-H groups, and the reaction was carried out at 80°C for 3 hours. The fraction was then removed by distillation under reduced pressure (90°C, 1.3 kPa), yielding organopolysiloxane (A-3) (yield: 950 g). The resulting organopolysiloxane (A-3) was a colorless, transparent liquid with a kinematic viscosity of 320 mmH. 2 The ratio of the structural units in formula (1) was a=0.02, b=0.02, c=0, d=0.43, e=0.52, and f=0.01.

[0050] [ka]

[0051] [Comparative Example 1-1] 750 g of the organopolysiloxane (A-0) obtained in Synthesis Example 1 and 620 g of the organohydrogenpolysiloxane represented by the above formula (4) were mixed in a 3 L separable flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer. The reaction molar ratio of vinyl groups to Si-H groups was 4:1. While stirring at 80°C, 0.0004 moles of a 1,3-divinyltetramethyldisiloxane complex of Pt(0) was added per mole of Si-H groups, and the reaction was carried out at 80°C for 3 hours. The fraction was then removed by vacuum distillation (90°C, 1.3 kPa), yielding organopolysiloxane (A-4) (yield: 1,350 g). The resulting organopolysiloxane (A-4) was a colorless, transparent liquid with a kinematic viscosity of 420 mmH. 2 The ratio of the structural units in formula (1) was a=0, b=0.02, c=0, d=0.43, e=0.53, and f=0.02.

[0052] [Comparative Example 1-2] 750 g of the organopolysiloxane (A-0) obtained in Synthesis Example 1 and 240 g of the organohydrogenpolysiloxane represented by the above formula (7) were mixed in a 3 L separable flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer. The reaction molar ratio of vinyl groups to Si-H groups was 2:1. While stirring at 80°C, 0.0004 moles of a 1,3-divinyltetramethyldisiloxane complex of Pt(0) was added per mole of Si-H groups, and the reaction was carried out at 80°C for 3 hours. The fraction was then removed by vacuum distillation (90°C, 1.3 kPa), yielding organopolysiloxane (A-5) (yield: 1,000 g). The resulting organopolysiloxane (A-5) was a colorless, transparent liquid with a kinematic viscosity of 450 mmH. 2 The ratio of the structural units in formula (1) was a=0, b=0.04, c=0, d=0.43, e=0.52, and f=0.01.

[0053] [2] Preparation of room temperature curable organopolysiloxane composition [Examples 2-1 to 2-6, Comparative Examples 2-1 to 2-3] The components below were mixed in the proportions shown in Table 1 to produce room-temperature-curable organopolysiloxane compositions (i) to (ix).

[0054] Component (A) (A-1): Organopolysiloxane obtained in Example 1-1 (A-2): Organopolysiloxane obtained in Example 1-2 (A-3): Organopolysiloxane obtained in Examples 1-3 (A-4): Organopolysiloxane obtained in Comparative Example 1-1 (A-5): Organopolysiloxane obtained in Comparative Example 1-2

[0055] (B) Component D-20: Titanium catalyst (titanium chelate compound) manufactured by Shin-Etsu Chemical Co., Ltd. Orgatix TC-750: Titanium catalyst (titanium chelate compound) manufactured by Matsumoto Fine Chemical Co., Ltd. (C) Component KBM-22: Dimethyldimethoxysilane manufactured by Shin-Etsu Chemical Co., Ltd. KBM-103: Phenyltrimethoxysilane manufactured by Shin-Etsu Chemical Co., Ltd.

[0056] The resulting room-temperature-curable organopolysiloxane compositions were evaluated for stability and tack-free time by the following methods. The results are shown in Table 1. (1) Stability The resulting compositions were stored in sealed bottles at 23°C and 50% RH, and those that showed no change in appearance after 14 days were marked with a ◯, and those that showed thickening or gelation were marked with an ×. (2) Tuck-free time The tack-free time was measured at 23°C and 50% RH in accordance with JIS K 6249. The obtained composition was placed flat in an aluminum dish (sample thickness: 3 mm) taking care to prevent bubbles from forming, and then the surface was lightly touched with a fingertip cleaned with ethanol. If the time it took for the sample to no longer adhere to the fingertip was within 10 minutes, it was evaluated as ◯, and if it took longer than 10 minutes, it was evaluated as ×.

[0057] [Table 1]

[0058] [3] Preparation and evaluation of cured products [Examples 3-1 to 3-6, Comparative Examples 3-1 to 3-3] The curable compositions (i) to (ix) obtained in Examples 2-1 to 2-6 and Comparative Examples 2-1 to 2-3 were placed flat in an aluminum dish to prevent bubbles from forming, and left to stand at 23°C and 50% RH for 7 days to obtain sheet-like cured products. The obtained cured products were evaluated for coating appearance and hardness. The results are shown in Table 2. (3) Coating appearance When visually inspected, the coating film surface was uniform, free of irregularities due to aggregates or waviness due to cure shrinkage, and not cloudy, and was rated as ○; the coating film surface was non-uniform, with whitening, irregularities due to aggregates, or waviness due to cure shrinkage, and was rated as ×. (4)Hardness Hardness was measured according to JIS K6249 as follows. The organopolysiloxane composition was molded into a 2 mm thick sheet and then allowed to stand at 23°C and 50% RH for 7 days to cure. Three of the resulting cured sheets were then stacked to a thickness of 6 mm, and the hardness was measured using a durometer (Type A).

[0059] [Table 2]

[0060] As shown in Tables 1 and 2, the curable compositions obtained in Examples 1-1 to 1-6 have short tack-free times, excellent curability, and no stability problems. Furthermore, the cured products of these compositions also have excellent appearance and hardness. On the other hand, the compositions of Comparative Examples 1-1 and 1-2 had long tack-free times and insufficient curability, and when the composition of Comparative Example 1-3, which contained an excessive amount of condensation catalyst, was used, the curability and hardness of the cured product were sufficient, but the stability was poor.

Claims

1. An organopolysiloxane having a structural unit ratio represented by the following formula (1): 【Chemical 1】 (In the formula, R 1 and R 2 each independently represents an unsubstituted or halogen-substituted alkyl group having 1 to 12 carbon atoms, or an unsubstituted or substituted aryl group having 6 to 10 carbon atoms; k represents an integer of 1 to 3; m represents a number of 5 to 100; n represents 2 or 3; R 3 , R 4 and R 5 each independently represents an unsubstituted or substituted alkyl group having 1 to 12 carbon atoms, an unsubstituted or substituted alkenyl group having 2 to 8 carbon atoms, an unsubstituted or substituted aryl group having 6 to 10 carbon atoms, an unsubstituted or substituted aralkyl group having 7 to 10 carbon atoms, an unsubstituted or substituted alkoxy group having 1 to 4 carbon atoms, or a hydroxy group; and a, b, c, d, e, and f represent numbers that satisfy a>0, b>0, c≧0, d>0, e>0, f≧0, and a+b+c+d+e+f=1.

2. The R 1 and R 2 The organopolysiloxane according to claim 1, wherein each independently represents a methyl group or an ethyl group.

3. Kinematic viscosity at 25°C: 100 to 2,000 mm 2 2. The organopolysiloxane of claim 1, wherein the formula is:

4. 2. The organopolysiloxane according to claim 1, which has a weight average molecular weight (Mw) of 1,000 to 50,000 in terms of polystyrene as determined by gel permeation chromatography.

5. (A) 100 parts by mass of the organopolysiloxane according to claim 1, and (B) Condensation reaction catalyst: 0.1 to 15 parts by mass A room temperature curable organopolysiloxane composition comprising:

6. 6. The room-temperature-curable organopolysiloxane composition according to claim 5, wherein component (B) comprises an organotitanium compound.

7. 6. The room-temperature-curable organopolysiloxane composition according to claim 5, further comprising: (C) a silane compound represented by the following general formula (2) in an amount of 0.5 to 50 parts by mass per 100 parts by mass of component (A): R 6 g Si(OR 7 ) 4-g (2) (In the formula, R 6 each independently represents an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, or an acyl group having 2 to 8 carbon atoms; R 7 represents an alkyl group having 1 to 8 carbon atoms or an acyl group having 2 to 8 carbon atoms, and g represents an integer of 0 to 3.

8. 6. The room-temperature-curable organopolysiloxane composition according to claim 5, wherein the content of the solvent is 1% by mass or less based on the total mass of the composition.

9. An electric or electronic part sealed, fixed or adhered with a cured product of the room temperature curable organopolysiloxane composition of any one of claims 5 to 8.

10. A conformal coating comprising the room temperature curable organopolysiloxane composition according to any one of claims 5 to 8.

Images