Coating composition, structure having coating layer, and method for producing the same

Abstract

To provide a new coating composition and the like capable of providing a sliding surface with superior sliding properties.SOLUTION: A coating composition comprising a linear organopolysiloxane having an alkenyl group at one molecular terminal and a hydrogen group bonded to Si at the other molecular terminal, and comprising an organohydrogenpolysiloxane having at least two hydrogen groups bonded to Si in one molecule.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a coating composition, a structure having a coating layer, and a method for producing the same. [Background technology]

[0002] There is a demand for technology that can impart lubricity to various structures without using lubricants. For example, in conventional disposable syringes, lubricants such as silicone oil are applied to the inner wall of the barrel and the syringe gasket to impart lubricity. Furthermore, prefilled syringes (PFS) are pre-filled with a drug solution, but because the drug solution is in contact with the syringe for long periods of time, there is a risk of contamination due to detachment and protein aggregation centered around the detached oil droplets, making it impossible to use lubricants. For PFS and other syringes, there is a demand for technology that can impart stable lubricity to syringes without using lubricants.

[0003] In Patent Document 1, a syringe gasket is coated with a film made of a fluororesin with a low coefficient of friction, and the surface roughness of the resin layer is adjusted with a filler, thereby imparting slidability to the syringe.

[0004] Patent Document 2 discloses forming a slidable silicone resin layer on a syringe gasket by curing a reactive silicone having terminal silanol groups through a condensation reaction catalyzed by an organotin compound. Patent Document 3 discloses forming a slidable silicone resin layer on a syringe gasket by addition curing a first siloxane containing at least two alkenyl groups and a second organopolysiloxane containing at least two hydrogen pendant groups and different from the first organopolysiloxane. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-89717 [Patent Document 2] WO2009-084646 publication [Patent Document 3] Special Publication No. 2009-532530 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the fluororesin described in Patent Document 1 is classified as a PFAS (perfluoroalkyl or polyfluoroalkyl compound), and its use may be restricted due to its high environmental persistence. Furthermore, the sliding property imparting technology described in Patent Document 2 requires an organotin compound catalyst as an essential component, but in recent years, its use has been restricted due to its toxicity and environmental impact. The sliding property technology described in Patent Document 3 solves the problem of organotin compounds, but after extensive research, the inventors have discovered a new issue: that the sliding property and sliding resistance may not be consistent. In such cases, the technology is insufficient as a sliding property imparting technology in fields such as syringes, where stable and consistent sliding resistance is required.

[0007] Under these circumstances, an object of the present invention is to provide a new coating composition or the like that imparts excellent sliding properties to a sliding surface. [Means for solving the problem]

[0008] The present inventors have conducted extensive research to solve the above problems and have found that the following inventions meet the above objectives, thereby completing the present invention.

[0009] <1> A coating composition comprising a linear organopolysiloxane having an alkenyl group at one molecular end and a hydrogen group bonded to Si at the other molecular end, and an organohydrogenpolysiloxane having at least two hydrogen groups bonded to Si per molecule. <2> A coating composition comprising a linear organopolysiloxane having an alkenyl group at one of its molecular ends and a hydrogen group bonded to Si at the other molecular end, A coating composition characterized in that the molar amount of alkenyl groups in the linear organopolysiloxane is 0.30 times or more and 1.0 times or less relative to the total unsaturated groups in the coating composition. <3> The above-mentioned organohydrogenpolysiloxane further contains at least two hydrogen groups bonded to Si in one molecule. <2> The coating composition according to claim 1. <4> The above-mentioned method further comprises the step of containing solid particles having a median diameter of 0.01 μm or more. <1> ~ <3> 1. The coating composition according to any one of the preceding claims. <5> The above-mentioned composition is a sliding coating composition. <1> ~ <4> 1. The coating composition according to any one of the preceding claims. <6> The method according to any one of claims 1 to 4, further comprising an addition reaction catalyst. <5> The coating composition according to claim 1. <7> The aforementioned <6> 1. A method for producing a structure having a coating layer, comprising a step of applying the coating composition according to claim 1 to a portion of the structure to which slidability is to be imparted, to form a slidable coating layer. <8> The aforementioned <6> A structure having a coating layer formed by curing the coating composition according to claim 1. [Effects of the Invention]

[0010] The coating composition of the present invention can impart slidability to the sliding surface of a structure. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram of a gasket shape for a syringe. [Figure 2] FIG. 1 is a schematic diagram of a syringe shape. [Figure 3] This is an image of the solid particles in the coating composition. [Figure 4] This is an image of the solid particles in the coating composition. [Figure 5] This is an image relating to the area measurement of the solid particles in FIG. [Figure 6] This is an image relating to the area measurement of the solid particles in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] The following describes in detail an embodiment of the present invention, but the following description of the constituent elements is one example (typical example) of an embodiment of the present invention, and the present invention is not limited to the following content unless the gist of the present invention is changed. Note that when the expression "to" is used in this specification, it is used as an expression that includes the numerical values ​​before and after it.

[0013] [Coating composition of the present invention] The coating composition of the present invention contains an organopolysiloxane having an alkenyl group at one of the molecular terminals and a hydrogen group bonded to Si at the other molecular terminal.

[0014] [AH-organopolysiloxane (alkenyl-terminated, Si-H-terminated organopolysiloxane)] The coating composition of the present invention contains an organopolysiloxane having an alkenyl group at one molecular end and a hydrogen group bonded to Si at the other molecular end. This organopolysiloxane having an alkenyl group at one molecular end and a hydrogen group bonded to Si at the other molecular end may be abbreviated as "AH-organopolysiloxane" in the present application. Coating layers formed using AH-organopolysiloxane exhibit sliding properties. AH-organopolysiloxanes are linear organopolysiloxanes. Meanwhile, in AH-organopolysiloxanes, the alkenyl group reacts with the H of the hydrogen group bonded to the Si at the end to form an elongated bond, forming a cyclic siloxane polymer.

[0015] [Alkenyl group] AH-Alkenyl group of organopolysiloxane (C n H 2n-1Examples of the alkenyl group include vinyl, allyl, propenyl, isopropenyl, butenyl, hexenyl, and cyclohexenyl. The alkenyl group of the AH-organopolysiloxane is preferably a lower alkenyl group such as vinyl or allyl. The alkenyl group of the AH-organopolysiloxane reacts with the H group bonded to the terminal Si.

[0016] [Si-H group] AH-organopolysiloxanes have hydrogen groups bonded to the terminal Si atoms. The structure of hydrogen groups bonded to Si atoms is sometimes abbreviated as "Si-H groups" in this application. The same applies to other polysiloxanes, such as organohydrogenpolysiloxanes. These Si-H groups react with alkenyl groups.

[0017] [Organopolysiloxane] AH-organopolysiloxane is a diorganopolysiloxane. The diorganopolysiloxane skeleton has a structure in which multiple dimethylsiloxanes are bonded, and examples of diorganopolysiloxanes in which the alkenyl groups are vinyl groups include those shown in the following formulas (1) and (2).

[0018] [ka]

[0019] In formula (1), n ​​is preferably 6 or more, more preferably 6 to about 1,000, and even more preferably about 10 to about 500.

[0020] [ka]

[0021] The compound of formula (2) can be obtained, for example, as shown in the following formula, by reacting an organopolysiloxane having vinyl groups at both ends with an organopolysiloxane having Si-H groups at both ends, resulting in a reaction between the vinyl groups and the Si-H groups.

[0022] [ka]

[0023] In formula (2), m1 and m2 are each preferably 3 or greater, more preferably 3 to 500, and even more preferably 5 to 250. If n, m1, or m2 is too short, intramolecular and intermolecular entanglement is reduced, preventing sliding properties and increasing the amount of elution of independent cyclic siloxanes. If they are too long, the viscosity of the AH-organopolysiloxane itself increases, making it difficult to work with, curing takes too long, and the individual molecules that make up the network formed by intramolecular and intermolecular entanglement in the cured coating layer are too long, reducing molecular mobility and preventing sliding properties.

[0024] The molecular weight of the AH-organopolysiloxane is preferably 300 or more, more preferably 300 to 80,000, even more preferably 400 to 60,000, and even more preferably 500 to 40,000. If the molecular weight is too small, intramolecular and intermolecular entanglement will be reduced, preventing sliding properties and increasing the amount of elution of independent cyclic siloxanes. If the molecular weight is too large, the viscosity of the AH-organopolysiloxane itself will be high, making it difficult to work with, curing will take too long, and the individual molecules that make up the network formed by intramolecular and intermolecular entanglement in the cured coating layer will be too long, reducing molecular mobility and preventing sliding properties.

[0025] The amount of each of the alkenyl and Si-H functional groups in the AH-organopolysiloxane is preferably 0.01 mmol / g or more, more preferably 0.01 mmol / g to 2.5 mmol / g, and even more preferably 0.02 mmol / g to 1.5 mmol / g. If the amount of functional groups is too low, intramolecular and intermolecular entanglement is reduced, preventing sliding properties and increasing the amount of elution of independent cyclic siloxanes. If the amount of functional groups is too high, the viscosity of the AH-organopolysiloxane itself may increase, making it difficult to work with, taking too long to cure, or the individual molecules that make up the network formed by intramolecular and intermolecular entanglement in the cured coating layer may be too long, reducing molecular mobility and preventing sliding properties.

[0026] The coating composition of the present invention is characterized by containing an AH-organopolysiloxane having a specific structure. The AH-organopolysiloxane used in the coating composition of the present invention has the following characteristics: First, the AH-organopolysiloxane alone can undergo an addition reaction, resulting in the formation of cyclic molecules of various sizes. These cyclic molecules then form a network of various sizes of intramolecular and intermolecular entanglements, resulting in elastomeric properties. In the case of a crosslinked structure, stress tends to concentrate on relatively short molecular chains when an external force is applied, resulting in severance at those locations. However, in the case of a network structure formed by entanglement, the cyclic molecules have a high degree of freedom and are easily mobile, resulting in less localized stress concentration and greater resistance to deformation (e.g., tear resistance and good elongation). Therefore, the coating composition of the present invention is believed to impart excellent sliding properties to sliding surfaces and to suppress an increase in sliding resistance after the initial sliding resistance.

[0027] [Coating composition] The coating composition is a composition that imparts physical properties to the coating composition by forming a coating layer by applying the composition. The physical properties of the coating composition can impart sliding properties, and the coating composition can also be used as a sliding coating composition for imparting sliding properties. For example, by applying the coating composition to a syringe gasket or the like of a syringe and forming a cured coating layer, a syringe can be obtained that has excellent sliding properties and exhibits little increase in sliding resistance after the initial sliding resistance.

[0028] The coating composition of the present invention is primarily composed of an AH-organopolysiloxane. When used, the coating composition of the present invention can be mixed with an appropriate catalyst and cured under reaction conditions to form a coating layer.

[0029] The coating composition of the present invention can consist essentially of AH-organopolysiloxane. Furthermore, it can be mixed with other components as appropriate, taking into consideration reactivity, storage properties, etc. Examples of components that can be mixed with the coating composition of the present invention include crosslinkers, catalysts, solid particles, solvents, cure inhibitors, adhesion promoters, surfactants, and the like.

[0030] The amount of each component in the coating composition of the present invention can be adjusted appropriately depending on the thickness of the coating layer, etc. The amount of AH-organopolysiloxane in the coating composition can be 10 parts by mass or more per 100 parts by mass of the coating composition. The lower limit of the amount of AH-organopolysiloxane can be 20 parts by mass or more, 30 parts by mass or more, 40 parts by mass or more, or 50 parts by mass or more, as appropriate. The upper limit of the amount of AH-organopolysiloxane can be 99.5 parts by mass or less, 99 parts by mass or less, 98 parts by mass or less, 95 parts by mass or less, 90 parts by mass or less, 80 parts by mass or less, etc.

[0031] [catalyst] The coating composition of the present invention may contain a catalyst, which promotes the addition reaction (hydrosilylation reaction) between the alkenyl groups of the AH-organopolysiloxane and the Si-H groups when the coating composition is applied to form a coating layer.

[0032] The catalyst may be a hydrosilylation catalyst. Examples of the catalyst include platinum group metals such as platinum (including platinum black), rhodium, and palladium; platinum chloride, chloroplatinic acid, and chloroplatinic acid salts such as HPtCl·nH0, HPtCl·nH0, NaHPtCl·nH0, KHPtCl·nH0, NaPtCl·nH0, KPtCl·nH0, PtCl·nH0, PtCl, and NaHPtCl·nH0 (where n is an integer of 0 to 6); reaction products of chloroplatinic acid with monohydric alcohols; complexes of chloroplatinic acid with olefins; platinum black, palladium, or other platinum group metals supported on alumina, silica, carbon, or other carriers; and complexes of platinum chloride, chloroplatinic acid, or chloroplatinic acid salts with vinyl group-containing siloxanes. Among these, from the viewpoint of catalytic activity, a complex of chloroplatinic acid with an olefin, a complex of platinum chloride, chloroplatinic acid or a chloroplatinate with a vinyl group-containing siloxane, etc. are preferred. These catalysts may be used alone or in combination of two or more.

[0033] The concentration of the catalyst, when present, can be adjusted appropriately depending on the reaction rate when the catalyst is used, stability during storage, etc., and is, for example, preferably 0.1 ppm or more, more preferably 0.1 ppm to 1,000 ppm, and even more preferably 1 ppm to 500 ppm relative to the total amount of solids. The solids referred to here include the base agent, crosslinking agent, solid particles, and other non-volatile components. The base agent is AH-organopolysiloxane, which is the main component of the coating composition.

[0034] [Crosslinking agent] The coating composition of the present invention may contain a crosslinking agent. The crosslinking agent is an organohydrogenpolysiloxane containing at least two hydrogen atoms bonded to silicon atoms (i.e., Si-H groups). The number of hydrogen atoms bonded to the silicon atoms may be three or more. The number of hydrogen atoms bonded to the silicon atoms is preferably about 2 to 150, and may be about 3 to 100 or 3 to 60, for example.

[0035] When forming the coating layer, the crosslinking agent forms a network with a crosslinked structure through an addition reaction with the AH-organopolysiloxane. Of the cyclic molecules formed by the addition reaction of only the AH-organopolysiloxane, independent cyclic molecules without intra- or inter-molecular entanglement hang like pendants from this crosslinked network, functioning like a bearing and providing excellent sliding properties. It is also thought to prevent the independent cyclic molecules from leaching out of the coating layer after curing. The crosslinking agent also promotes the addition reaction, allowing the coating layer to form quickly.

[0036] The molecular structure of the crosslinking agent is not particularly limited and may be any of linear, branched, cyclic, and network structures. Organohydrogenpolysiloxanes having a silicon atom count (or degree of polymerization) of typically 4 to 300, and particularly 5 to 150, per molecule are preferably used.

[0037] As such a crosslinking agent, for example, one having the following average composition formula can be used. H a R a1 b SiO (4-a-b) / 2 (In the formula, R a1is independently an unsubstituted or substituted monovalent hydrocarbon group that does not contain an aliphatic unsaturated bond, preferably having 1 to 10 carbon atoms, more preferably 1 to 7 carbon atoms. a and b are numbers satisfying 0 < a < 2, 0.8 ≤ b ≤ 2, and 0.8 < a + b ≤ 3. Preferably, they are numbers satisfying 0.05 ≤ a ≤ 1, 0.9 ≤ b ≤ 2, and 1 ≤ a + b ≤ 2.7. Examples include organohydrogenpolysiloxanes represented by ).

[0038] In the formula, R a1 Examples of include monovalent hydrocarbon groups. Among them, lower alkyl groups having 1 to 3 carbon atoms such as methyl group and phenyl group are particularly preferred.

[0039] Specific examples of the crosslinking agent include siloxane oligomers such as 1,3,5,7 - tetramethyltetracyclosiloxane and 1,3,5,7,8 - pentamethylpentacyclosiloxane; methylhydrogenpolysiloxane blocked with trimethylsiloxy groups at both ends of the molecular chain, dimethylsiloxane·methylhydrogensiloxane copolymer blocked with trimethylsiloxy groups at both ends of the molecular chain, methylhydrogenpolysiloxane blocked with silanol groups at both ends of the molecular chain, dimethylsiloxane·methylhydrogensiloxane copolymer blocked with silanol groups at both ends of the molecular chain, dimethylpolysiloxane blocked with dimethylhydrogensiloxy groups at both ends of the molecular chain, methylhydrogenpolysiloxane blocked with dimethylhydrogensiloxy groups at both ends of the molecular chain, dimethylsiloxane·methylhydrogensiloxane copolymer blocked with dimethylhydrogensiloxy groups at both ends of the molecular chain, etc.; R a1 2(H)SiO 1 / 2 units and SiO 4 / 2 units, and further contain R a1 3SiO 1 / 2 units, R a1 2SiO 2 / 2 units, R a1 (H)SiO 2 / 2 units, (H)SiO 3 / 2 units or R a1 SiO 3 / 2 units, and a silicone resin having a three - dimensional network structure that may contain R a1is the same as above), and the like.

[0040] The organohydrogenpolysiloxane crosslinking agent can be obtained by a known method. For example, a1 SiHCl2 and R a1 2SiHCl (where R a1 is the same as above), or by co-hydrolyzing the chlorosilane compound with at least one chlorosilane compound selected from the group consisting of chlorosilane compounds of the general formula: R a1 3SiCl and R a1 2SiCl2 (wherein, R a1 are the same as above) and co-hydrolyzing them together, and they may also be equilibrated.

[0041] The amounts of AH-organopolysiloxane and crosslinker used are such that the total amount of Si-H groups in the AH-polyorganosiloxane and crosslinker is preferably 0.5 to 5.0 moles, more preferably 0.8 to 2.5 moles, per mole of alkenyl groups in the entire composition. When the amount of Si-H groups is within this range, the composition tends to cure sufficiently, does not take too long, and a cured product with the required strength is easily obtained. Furthermore, the composition is less likely to foam during curing, and the physical properties of the cured product are less likely to change over time.

[0042] The coating composition of the present invention may contain solid particles. Specific examples of the solid particles will be described later.

[0043] When solid particles are contained, the concentration can be adjusted appropriately depending on the sliding properties of the solid particles, stability during storage, etc. The lower limit of the amount of solid particles can be 1 part by mass or more, 5 parts by mass or more, or 10 parts by mass or more, when the total amount of solids is 100 parts by mass. The upper limit of the amount of solid particles can be 60 parts by mass or less, 55 parts by mass or less, 50 parts by mass or less, or 45 parts by mass or less, when the total amount of solids is 100 parts by mass. If the amount of solid particles is too low, the sliding properties and mechanical strength of the cured coating layer may be insufficient, and the elution of cyclic siloxanes may increase. If the amount of solid particles is too high, the sliding properties of the cured coating layer may be insufficient, and the solid particles may be more likely to detach.

[0044] [solvent] The coating composition of the present invention may contain a solvent. The coating layer may be thin and have sliding properties, so it is preferable that the coating layer has high fluidity so that it can be easily applied to the structure to be coated. The solvent can be appropriately adjusted depending on the effect on the volatilization temperature, stability, reactivity, etc.

[0045] The solvent is preferably one that can dissolve or uniformly disperse the coating composition and volatilizes without leaving any residue during the thermal curing process. Examples of solvents that can be used include water; hydrocarbon solvents such as benzene, toluene, xylene, n-hexane, cyclohexane, and n-heptane; ether solvents such as tetrahydrofuran, 1,4-dioxane, and diisosylpropyl ether; ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; ester solvents such as ethyl acetate and butyl acetate; alcohol solvents such as butanol and 2-ethylhexanol; and halogenated solvents such as chloroform and 1,2-dichloroethane. Aprotic solvents such as toluene, n-heptane, tetrahydrofuran, methyl ethyl ketone, and methyl isobutyl ketone are particularly preferred because they can easily dissolve the composition. Meanwhile, water and alcohol solvents are preferred because they have a low environmental impact. Two or more solvents can also be used as a mixed solvent as long as they do not separate after mixing.

[0046] [Cure inhibitor] The coating composition of the present invention may contain a curing inhibitor to control reactivity and improve storage stability. Examples of the curing inhibitor include acetylene compounds such as 1-ethynyl-1-cyclohexanol, 3-methyl-1-butyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, and 3-phenyl-1-butyn-3-ol; ene compounds such as 3-methyl-3-penten-1-yne and 3,5-dimethyl-3-hexen-1-yne; maleic anhydride and dimethyl maleate; 1,3-divinyl-1,1,3,3-tetramethyldisiloxane, 1,3-divinyl-1,1,3, Examples of compounds include vinyl group-containing siloxane compounds such as 3-tetraphenyldisiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, and 1,3,5,7-tetramethyl-1,3,5,7-tetrahexenylcyclotetrasiloxane; organic phosphorus compounds such as triorganophosphines; organic sulfur compounds such as thiazole; nitrogen-containing compounds such as N,N,N',N'-tetramethylethylenediamine; organic peroxides, and mixtures thereof. The amount of the cure inhibitor is preferably 0.001 to 5.0 parts by mass, and more preferably 0.005 to 5.0 parts by mass, per 100 parts by mass of the total solids content.

[0047] [Preparation ingredients, optional ingredients] The coating composition of the present invention may also contain other components such as an organopolysiloxane containing at least two alkenyl groups, an adhesion promoter, a surfactant, an extender, a viscosity modifier, and the like.

[0048] [Organopolysiloxane containing at least two alkenyl groups] The organopolysiloxane containing at least two alkenyl groups may be linear or cyclic, and in either case, the molecule may contain a branched structure. From the perspective of physical properties such as the mechanical strength of the cured product, a linear diorganopolysiloxane whose main chain is essentially composed of repeating diorganosiloxane units is preferred. There are no particular restrictions on the location of the alkenyl groups. When the organopolysiloxane containing at least two alkenyl groups is linear, the alkenyl groups may be present at either the terminal or non-terminal portions of the molecular chain, or may be present at both. Both ends of the linear diorganopolysiloxane are usually blocked with triorganosiloxy groups.

[0049] Preferred examples of organopolysiloxanes containing at least two alkenyl groups include diorganopolysiloxanes represented by the following general formula: R b2 -Si(R b1 )O-[Si(R b1 )2O] n -[Si(R b1 )(X)O] m -Si(R b1 )2-R b2 (In the formula, R b1 are independently an unsubstituted or substituted monovalent hydrocarbon group containing no aliphatic unsaturated bonds, preferably having 1 to 10 carbon atoms, more preferably having 1 to 6 carbon atoms; X is an alkenyl group preferably having 2 to 8 carbon atoms, more preferably having 2 to 5 carbon atoms; R b2 are independently R b1 or X, where n is an integer of 0 or more, and m is an integer of 0 or more such that the number of alkenyl groups bonded to silicon in the molecule is 2 or more. However, n+m is preferably an integer of 10 to 10,000, more preferably 50 to 2,000, and m / (n+m) is preferably a number of 0 to 0.2. The value of m is specifically determined by the ratio of R b2 One of them is R b1 If the other is X, it is an integer greater than or equal to 1, and R b2 Both are R b1 , it is an integer greater than or equal to 2.)

[0050] R b1 Examples of the alkyl group include monovalent hydrocarbon groups. Among these, unsubstituted or substituted alkyl groups having 1 to 3 carbon atoms, such as methyl, ethyl, propyl, chloromethyl, bromoethyl, 3,3,3-trifluoropropyl, and cyanoethyl, and unsubstituted or substituted phenyl groups, such as phenyl, chlorophenyl, and fluorophenyl, are particularly preferred. Examples of X include alkenyl groups, and among these, lower alkenyl groups such as vinyl and allyl are particularly preferred.

[0051] The kinematic viscosity of organopolysiloxane containing at least two alkenyl groups at 25°C is 10 to 1,000,000 mm 2 / sec, and 100 to 500,000 mm 2 / sec is more preferable.

[0052] Examples of adhesion aids for improving adhesion include silane coupling agents such as methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, γ-ureidopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, bis(trimethoxysilyl)propane, and bis(triethoxysilyl)propane; Examples of suitable silane coupling agents include silane coupling agents having a butadiene polymer structure, such as X-12-1267B, X-12-1281A, and X-12-1287A; titanium compounds, such as titanium ethylacetonate and titanium acetylacetonate; aluminum compounds, such as ethylacetoacetate aluminum diisopropylate, aluminum tris(ethylacetoacetate), alkylacetoacetate aluminum diisopropylate, aluminum tris(acetylacetonate), and aluminum monoacetylacetonate bis(ethylacetoacetate); and zirconium compounds, such as zirconium acetylacetonate, zirconium butoxyacetylacetonate, zirconium bisacetylacetonate, and zirconium ethylacetoacetate. Silane coupling agents, such as methyltriethoxysilane, γ-ureidopropyltriethoxysilane, and 3-glycidoxypropyltrimethoxysilane, are particularly preferred. Preferably, silane coupling agents such as vinyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-aminopropyltrimethoxysilane, and 3-aminopropyltriethoxysilane, or silane coupling agents having a butadiene polymer structure can be used. More preferably, silane coupling agents having a butadiene polymer structure can be used.

[0053] When an adhesion promoter is added, the amount added is preferably 0.1 to 20 parts by mass, particularly 0.2 to 5 parts by mass, per 100 parts by mass of the AH-organopolysiloxane. If the amount is less than 0.1 part by mass, sufficient adhesion may not be obtained, while if the amount is more than 20 parts by mass, the physical properties of the cured coating composition may be affected, resulting in reduced sliding properties and durability of the coating film. The adhesion promoter may be used alone or in combination of two or more types.

[0054] [Ratio of alkenyl groups in AH-organopolysiloxane to total unsaturated groups in coating composition] The inclusion of a compound containing an unsaturated group other than AH-organopolysiloxane as a preparation component or optional component is preferred because it allows the coating composition of the present invention to be cured and the physical properties of the resulting coating layer to be more easily adjusted. These compounds containing unsaturated groups may be used alone or in combination, and may also be used in combination with other components, such as in the form of a complex with the aforementioned catalyst.

[0055] The unsaturated group is synonymous with an aliphatic unsaturated bond (i.e., an aliphatic carbon-carbon double bond or an aliphatic carbon-carbon triple bond), and is capable of undergoing a hydrosilylation reaction with a Si-H group. Examples of functional groups containing an unsaturated group include functional groups having a carbon-carbon double bond, such as an allyl group, a vinyl group, an acryloyl group, or a methacryloyl group, and functional groups having a carbon-carbon triple bond, such as an acetylenyl group, a propynyl group, a butynyl group, a pentynyl group, or a hexynyl group.

[0056] Furthermore, in order to fully utilize the effects of the AH-organopolysiloxane in the resulting coating layer after curing the coating composition of the present invention, it is preferable that the amount of alkenyl groups in the AH-organopolysiloxane relative to the total unsaturated groups in the coating composition be within a certain range. Specifically, the amount of alkenyl groups in the AH-organopolysiloxane relative to the total unsaturated groups in the coating composition is 0.30 molar or more, preferably 0.35 molar or more, and particularly preferably 0.40 molar or more. If the amount is less than this, the flexibility-improving effect of the AH-organopolysiloxane on the coating layer may not be fully exhibited. Furthermore, it is preferable that the amount of alkenyl groups in the AH-organopolysiloxane relative to the total unsaturated groups in the coating composition be 0.99 molar or less, preferably 0.98 molar or less, and particularly preferably 0.97 molar or less, because a synergistic effect of the AH-organopolysiloxane and other unsaturated group-containing compounds can be expected. The above upper and lower limits can be combined as desired.

[0057] The ratio of alkenyl groups in the AH-organopolysiloxane to all unsaturated groups in the coating composition can be easily measured by known methods, such as measuring the proton nuclear magnetic resonance (NMR) spectrum of the composition.

[0058] [Si-H composition ratio of coating composition to total unsaturated groups in coating composition] In order to sufficiently cure the coating composition of the present invention and ensure consistent mechanical properties of the resulting coating layer, the ratio of Si-H groups in the composition to the total unsaturated groups in the coating composition is preferably within a certain range. Specifically, the ratio of Si-H groups in the coating composition to the total unsaturated groups in the coating composition is preferably 0.5 molar times or more, preferably 0.70 molar times or more, more preferably 0.75 molar times or more, and particularly preferably 0.80 molar times or more. Furthermore, the ratio of Si-H groups in the coating composition to the total unsaturated groups in the coating composition is preferably 5.00 molar times or less, preferably 2.50 molar times or less, more preferably 2.00 molar times or less, even more preferably 1.80 molar times or less, and particularly preferably 1.60 molar times or less. Outside this range, the coating composition may not be sufficiently cured, adversely affecting the physical properties of the coating layer. When the amount of Si-H groups is within this range, the composition is likely to cure sufficiently, curing does not take too long, and a cured product with the required strength is easily obtained. Furthermore, the composition is less likely to foam during curing, and the physical properties of the cured product are less likely to change over time. The above upper and lower limits can be combined in any desired manner.

[0059] The Si-H ratio of the coating composition to the total unsaturated groups in the coating composition can be easily measured by known methods, such as measuring the proton nuclear magnetic resonance (NMR) spectrum of the composition.

[0060] [Solid particles] When forming a coating layer, the solid particles affect the film quality and structure, thereby improving the sliding properties.

[0061] The solid particles may include inorganic or organic fillers. Preferably, the filler is made of at least one material selected from the group consisting of metals, metal oxides, metal hydroxides, metal nitrides, metal carbides, carbon allotropes, resins, dyes, and pigments. Examples of such fillers include metals such as aluminum, silver, copper, and metallic silicon; metal oxides such as alumina, zinc oxide, magnesium oxide, silicon dioxide, cerium oxide, and iron oxide; metal hydroxides such as aluminum hydroxide and cerium hydroxide; metal nitrides such as aluminum nitride and boron nitride; metal carbides such as silicon carbide; carbon allotropes such as diamond, graphite, carbon nanotubes, and graphene; resins such as silicone resin powder; dyes such as indigo; and pigments such as red iron oxide. More preferably, silicon dioxide such as hydrophobic fumed silica can be used, with hydrophobic fumed silica being particularly preferred. The solid particles may be in the form of primary particles or aggregates in the sliding coating layer. Furthermore, one type of solid particle or a mixture of two or more types of solid particles may be used.

[0062] Fumed silica typically does not consist of independent primary particles, but rather aggregates to form secondary particles, which then aggregate to form larger, more porous aggregates. It is speculated that the AH-organopolysiloxane or crosslinker penetrates the voids in the fumed silica, or that the silanol groups on the fumed silica surface react with the Si-H groups on the AH-organopolysiloxane or crosslinker, or that the silanol groups on the fumed silica surface react with each other to form a network structure consisting of the AH-organopolysiloxane, crosslinker, and fumed silica, thereby improving the mechanical strength of the cured coating. Additionally, the entanglement of the independent cyclic siloxanes with the network structure of the AH-organopolysiloxane, crosslinker, and fumed silica improves the sliding properties of the cured coating and inhibits the leaching of the independent cyclic siloxanes.

[0063] It is preferable to use solid particles having a median diameter of 0.01 μm or more. The lower limit of the median diameter of the solid particles can be, for example, 0.01 μm or more, 0.05 μm or more, or 0.1 μm or more. If the median diameter of the solid particles is too small, the solid particles tend to aggregate and the particle size cannot be maintained constant, which may result in poor storage stability of the coating composition.

[0064] It is preferable to use solid particles having a median diameter of 30 μm or less. The upper limit of the median diameter of the solid particles can be, for example, 30 μm or less, 25 μm or less, or 20 μm or less. If the median diameter of the solid particles is too large, coarse protrusions may form on the surface of the cured product, increasing sliding resistance, or the viscosity of the coating composition may change over time, making the film thickness unstable.

[0065] The coating composition of the present invention preferably has a viscosity of 500 mPa·s or less. The viscosity is measured using an E-type viscometer at 25°C. The viscosity is more preferably 400 mPa·s or less, or 300 mPa·s or less. By setting the viscosity in this range, the composition can be easily spread on a structure during application, making it easier to obtain a coating layer.

[0066] [Coating method] The method for producing a structure of the present invention includes a step of applying the coating composition of the present invention to a portion of the structure to which slidability is to be imparted, thereby forming a slidable coating layer. In order to increase the adhesion between the structure and the coating layer, the surface of the structure on which the coating layer is to be formed may be pretreated. Furthermore, the structure of the present invention has a coating layer formed by curing the coating composition of the present invention.

[0067] The coating composition can be applied by using a coater, by dipping into the coating composition, or by spraying.

[0068] The applied coating composition is cured to form a coating layer. This curing can be achieved by drying or, if appropriate, by heating. When a solvent or the like is contained, it is preferable to cure the composition by heating in order to volatilize the solvent or promote the reaction.

[0069] When heating for curing, the heating temperature can be, for example, 50° C. or higher, 60° C. or higher, 70° C. or higher, or 80° C. or higher. The upper limit of the heating temperature can be, for example, 150° C. or lower, or 120° C. or lower.

[0070] The heating time can be, for example, 10 minutes or more, 30 minutes or more, 1 hour or more, 2 hours or more, etc. The upper limit of the heating time can be, for example, 24 hours or less, 18 hours or less, 12 hours or less, etc.

[0071] The structure bearing the coating layer can be washed as needed. Washing the structure bearing the coating layer can remove uncured materials contained in the coating layer and dirt that has adhered during the coating and drying processes. Examples of cleaning methods include flow cleaning, ultrasonic cleaning, high-pressure cleaning, low-pressure cleaning, immersion cleaning, agitation cleaning, jet cleaning, and foam cleaning. Examples of cleaning media include water such as tap water, ion-exchanged water, and electrolyzed water; solvents; surfactants; acids; alkalis; cleaning agents such as enzyme cleaners; solids such as dry ice and baking soda; and gases such as ethylene oxide gas.

[0072] The drying step is a step of drying the structure having the coating layer after the washing step, and typically involves naturally drying the structure having the coating layer in the atmosphere. To accelerate the drying, for example, hot air at about 50 to 100°C may be blown onto the structure.

[0073] [Structure] The structure to be coated can be any structure that requires slidability. Examples of the structure include a syringe barrel, a syringe gasket, a guide wire, and a catheter. The material of the structure can be, for example, resin, metal, glass, ceramic, fiber, etc. Furthermore, the material of the sliding surface of the structure to be coated can be, for example, resin, metal, glass, ceramic, fiber, etc.

[0074] 1 and 2 show examples of structures, such as a syringe gasket shape. FIG. 1 is a schematic diagram of the syringe gasket shape. FIG. 2 is a schematic diagram of the syringe shape. Syringe gasket 1 has ribs 2 and 3 and a plunger connection part 4. Syringe barrel 5 has a cylindrical tip 6. Plunger 7 has syringe gasket connection part 8 for connecting with plunger connection part 4 of syringe gasket 1. With these connected, it is used by performing piston movement within syringe barrel 5.

[0075] The thickness of the coating layer of the structure of the present invention having a coating layer can be about 0.1 to 50 μm, 1 to 20 μm, or 1 to 10 μm. If the thickness is too thin, sliding properties may not be exhibited, or the mechanical properties of the coating layer may be insufficient. Even if the thickness is increased, the improvement effect of sliding properties, etc. is unlikely to exceed a certain level, and there is a risk of affecting the shape of the structure, so a thickness within the above-mentioned range may be sufficient. If the thickness is too thick, the film is more likely to break.

[0076] The structure of the present invention can be one in which the maximum sliding resistance of the structure of the present invention via the coating layer is 50 N or less at a sliding speed of 100 mm / min. By achieving such a sliding resistance, the structure can be one that is excellent in operability, such as when performing so-called piston movements. Furthermore, the structure of the present invention can be one in which the sliding resistance increase rate of the coating layer is 23% or less at a sliding speed of 100 mm / min. The sliding resistance increase rate can be determined by the method described below. A structure with a low sliding resistance increase rate is easy to operate because there is little change in sliding resistance during use. An increase in sliding resistance may occur due to peeling of the coating film, so it is preferable to keep the sliding resistance increase rate low. The upper limit of the sliding resistance increase rate can be, for example, 23% or less, 22% or less, 21% or less, 20% or less, 19% or less, 18% or less, 17% or less, 16% or less, or 15% or less. [Example]

[0077] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples as long as the gist of the present invention is not changed.

[0078] (Evaluation items) <Method for measuring the amount of unsaturated groups in polysiloxanes containing unsaturated groups> Approximately 50 mg of α-monovinyl-Ω-monohydride-terminated polydimethylsiloxane, polydimethylsiloxane containing vinyl groups at both ends, or 2,4,6,8-tetravinyl-2,4,6,8-tetramethylcyclotetrasiloxane was dissolved in approximately 1 g of deuterated chloroform by adding one drop of dimethyl sulfoxide to make a total mass of approximately 70 mg. Alternatively, approximately 50 mg of platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex solution was dissolved in approximately 1 g of deuterated dichloromethane by adding one drop of dimethylformamide to make a total mass of approximately 70 mg. 1 A sample for H-NMR measurement was prepared. 1The relaxation delay was measured for 20 seconds using H-NMR (JNM-ECZ400 manufactured by JEOL Ltd.). The ratio of the signal intensity of each component to the signal intensity of the internal standard, and the proportion of vinyl groups bonded to silicon atoms (Si-Vi group amount) were calculated in terms of the molar amount per mass from the weighing values.

[0079] <Method for measuring Si-H group amount> Approximately 50 mg of α-monovinyl-Ω-monohydride-terminated polydimethylsiloxane with one drop of dimethyl sulfoxide added to make the total mass approximately 70 mg, or approximately 50 mg of methylhydrogen siloxane-dimethylsiloxane copolymer with one drop of 1,1,2,2-tetrabromoethane added to make the total mass approximately 70 mg, was dissolved in approximately 1 g of deuterated chloroform 1 A sample for H-NMR measurement was prepared. 400 MHz 1 The relaxation delay was measured for 20 seconds using H-NMR (JNM-ECZ400 manufactured by JEOL Ltd.). The ratio of the signal intensity of each component to the signal intensity of the internal standard, and the proportion of hydrogen groups bonded to silicon atoms were calculated in terms of the molar amount per mass from the weighing values.

[0080] <Measurement of viscosity (25 °C)> The coating composition was set on an E-type viscometer (model: DV2TRVCJ0, manufactured by Brookfield) adjusted to 25 °C, and the measurement was started at a shear rate of 760 [1 / sec]. The value 15 seconds after the start of the measurement was read and taken as the viscosity (25 °C) of the coating composition.

[0081] <Calculation of solid content concentration> The solid content concentration of the coating composition was determined from the following formula. Solid content concentration [mass%] = (total mass of solids contained in the coating composition [g]) / (total mass of the coating composition [g]) × 100 Here, the solid content refers to the base agent, crosslinking agent, solid particles, and other nonvolatile components, and the mass of the entire coating composition refers to the total mass of the entire coating composition including not only the base agent, crosslinking agent, solid particles, and other nonvolatile components, but also curing inhibitors, catalysts, organic solvents, and the like.

[0082] <Calculation of density (25℃)> The specific gravity of the coating composition was calculated from the specific gravity and mass of each component contained in the coating composition and the mass of the entire coating composition, and the specific gravity of the coating composition and the density of water (997.062 kg / m 3 The density (25°C) of the coating composition was calculated from the density (25°C) of the coating composition.

[0083] <Calculation of theoretical film thickness> The thickness of the coating composition applied to the structure of the present invention (wet film thickness, h wet ) is considered to be governed by the surface tension at the gas-liquid interface and was calculated using the following equation.

[0084]

number

[0085] U is the withdrawal speed (m / s), η is the viscosity (Pa s), and ρ is the density of the coating composition (kg / m 3 , 25℃). g is the gravitational acceleration, 9.8 m / s 2 γ is the surface tension of the liquid (N / m, 25°C), where the surface tension of THF is 26.4 × 10 -3 N / m was used. (Reference: Marco Faustini et al., "Preparation of Sol-Gel Films by Dip-Coating in Extreme Conditions," J.Phys.Chem.C, 2010, Vol. 114, No. 17, pp. 7637-7645)

[0086] Film thickness after drying at 100°C for 8 hours (dry film thickness, h dry ) was calculated using the following formula: In the following formula, C is the solid content concentration [mass %].

[0087]

number

[0088] <Film thickness measurement> The syringe gasket having the sliding coating layer obtained in the examples was cut with a razor to obtain a slice. The rib portion of the slice was observed under an optical microscope, and the thickness of the coating film formed on the rib was measured. Measurements were taken at three random locations on each of the two ribs on the syringe gasket, and the arithmetic mean value of the measurements at a total of six locations was taken as the film thickness.

[0089] <Method for measuring sliding resistance> The syringe was fixed with the tip facing downward and placed on an autograph (EZ-SX, Shimadzu Corporation). The plunger was pressed down 60 mm at a speed of 100 mm / min, and the sliding resistance (N) was measured at 0.01 second intervals from 0 mm to 60 mm. After the start of pushing, the sliding resistance increased rapidly, reached a maximum value, then began to decrease, and then began to increase gradually again. The maximum value of this peak immediately after the start of pushing was read as the initial sliding resistance. The maximum value of the sliding resistance within a pushing distance of 60 mm from the peak was read as the maximum sliding resistance value. The sliding resistance values ​​at pushing distances of 20 mm (the position when the syringe was pushed down by 1 / 3 of its nominal capacity) and 60 mm (the position when the syringe was pushed down to its full nominal capacity) were also read, and the sliding resistance increase rate (%) was calculated using the following formula. Sliding resistance increase rate (%) = (sliding resistance at the position when the syringe is fully depressed to its nominal capacity) / (sliding resistance at the position when the syringe is depressed to 1 / 3 of its nominal capacity) x 100 - 100

[0090] The following raw materials were used: <Main ingredient: vinyl group-containing polydimethylsiloxane> α-Monovinyl-Ω-monohydride-terminated polydimethylsiloxane (Grade: DMS-HV22, manufactured by Gelest, kinematic viscosity 150-250 cSt, Si-Vi group content 0.067 mmol / g, Si-H group content 0.064 mmol / g) Polydimethylsiloxane containing vinyl groups at both ends (grade: PLY1-7500, manufactured by NuSil, kinematic viscosity 500 cSt, Si-Vi group content 0.154 mmol / g)

[0091] <Crosslinking agent: Hydrogen-containing polydimethylsiloxane> Methylhydrogensiloxane-dimethylsiloxane copolymer (Grade: XL-115, manufactured by NuSil, Si-H group content 4.240 mmol / g)

[0092] <Cure inhibitor> 2,4,6,8-Tetravinyl-2,4,6,8-tetramethylcyclotetrasiloxane (Grade: SIT7900.0, manufactured by Gelest, Si-Vi group content 11.63 mmol / g)

[0093] <Catalyst> Platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex solution (Grade: 479519, Merck, approximately 2% Pt, Si-Vi group content 0.321 mmol / g)

[0094] <Solid particles> Trimethylsilyl-modified fumed silica (grade: SIS6962.0, manufactured by Gelest)

[0095] <Solvent> Tetrahydrofuran (grade: 33112-75, manufactured by Nacalai Tesque)

[0096] [Example 1] [Preparation of Coating Liquid (1)] 10.50 g of α-monovinyl-Ω-monohydride-terminated polydimethylsiloxane and 4.50 g of fumed silica modified with trimethylsilyl groups were weighed into a 125 ml plastic container and mixed for 120 seconds at a rotation speed of 2000 rpm using a stirring degassing device (product name: Awatori Rentaro, manufactured by Thinky Corporation). Next, the plastic container after mixing was immersed in water up to about 1 / 3 of its height in a water bath, cooled with running water for 1 minute or more, and then removed from the water bath. The trimethylsilyl-modified fumed silica adhering to the inner wall of the plastic container was then scraped off with a stirring rod and mixed into the mixture, and the stirring rod was rotated about 50 times to knead the entire mixture. The same series of steps of mixing with the stirring degassing device, water cooling, and kneading with the stirring rod were repeated once more, and finally mixing with the stirring degassing device was carried out to obtain Mixture A, consisting of α-monovinyl-Ω-monohydride-terminated polydimethylsiloxane and trimethylsilyl-modified fumed silica. Next, 0.0105 g of platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex solution, 0.0100 g of 2,4,6,8-tetravinyl-2,4,6,8-tetramethylcyclotetrasiloxane, and 30.0 g of tetrahydrofuran as a viscosity modifier for the coating composition were weighed into a 100 ml glass bottle, and stirring was initiated using a stirrer (HE-20GA, Koike Precision Machinery Works, Ltd.). Then, 10.00 g of Mixture A and 0.100 g of a methylhydrogensiloxane-dimethylsiloxane copolymer were added, and the mixture was stirred for 5 minutes to obtain a coating composition with a solids concentration of 25.2% by mass. The calculated density (25°C) and measured viscosity (25°C) were 997.7 kg / m 3 The viscosity was 8.06 mPa·s. The composition of the resulting coating composition is shown in Table 1.

[0097] [Coating layer formation] A 20 ml plastic syringe (model SS-20ESZ, manufactured by Terumo Corporation) was used as the syringe gasket on which the coating layer was formed. Because the surface of the syringe gasket was coated with a lubricant, the syringe gasket was washed in advance with n-heptane and acetone to remove the lubricant. The obtained coating liquid was placed in a glass bottle having a volume of 50 ml, and a syringe gasket was immersed in the liquid and then pulled up at a speed of 2.2 mm / s. The coating was then air-dried overnight and then dried at 100°C for 8 hours, which not only cured the coating composition but also evaporated the xylene contained in the platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex solution and the tetrahydrofuran added as a viscosity modifier to the coating solution.

[0098] [Physical properties of the sliding coating layer] The composition and physical properties are shown in Table 1. Table 1 also lists the following items. Functional group ratio (total Si-H groups in coating composition / Si-Vi groups in main agent) Functional group ratio (total Si-H groups in the coating composition / total unsaturated groups in the coating composition) Functional group ratio (Amount of Si-Vi groups in AH-organopolysiloxane / Total amount of unsaturated groups in coating composition)

[0099] [Sliding resistance of the sliding coating layer] The coated syringe gasket, a syringe barrel, and a plunger were assembled to prepare a syringe. A 20 ml plastic syringe (model SS-20ESZ, manufactured by Terumo Corporation) was used for the syringe barrel and plunger. The syringe barrel surface was coated with a lubricant, so it was washed with n-heptane and acetone in advance to remove the lubricant. A syringe was fabricated by assembling a syringe barrel, plunger, and coated syringe gasket. The syringe gasket was placed at a position where rib 2 was 30 mm from the opening of the syringe barrel and left to stand overnight. The sliding resistance of the fabricated syringe was measured to determine the initial sliding resistance, maximum sliding resistance, and rate of increase in sliding resistance. The results are shown in Table 1.

[0100] [Example 2] 0.0075 g of platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex solution, 0.0070 g of 2,4,6,8-tetravinyl-2,4,6,8-tetramethylcyclotetrasiloxane, and 20.0 g of tetrahydrofuran were weighed into a 50 ml glass bottle and stirring was initiated. Then, 7.00 g of α-monovinyl-Ω-monohydride-terminated polydimethylsiloxane and 0.100 g of methylhydrogensiloxane-dimethylsiloxane copolymer were added and stirred for 5 minutes to obtain a coating composition with a solids concentration of 26.2 mass%. The calculated density (25°C) and measured viscosity (25°C) were 906.8 kg / m, respectively. 3 , and 4.86 mPa s. A syringe gasket of the same type as that used in Example 1 was immersed in the obtained coating composition and pulled up at a speed of 3.2 mm / s, and a coating film was formed on the syringe gasket in the same manner as in Example 1, thereby producing a syringe. The sliding resistance of the produced syringe was measured, and the initial sliding resistance, maximum sliding resistance, and sliding resistance increase rate were determined. The results are shown in Table 1.

[0101] [Comparative Example 1] 10.50 g of polydimethylsiloxane containing vinyl groups at both ends and 4.50 g of fumed silica modified with trimethylsilyl groups were weighed into a 125 ml plastic container and mixed for 120 seconds using a stirring / defoaming device (product name: Awatori Rentaro, manufactured by Thinky Corporation) at a rotation speed of 2000 rpm. The mixed plastic container was then immersed in a water bath to approximately one-third of its height and cooled with running water for at least one minute, after which it was removed from the water bath. The trimethylsilyl-modified fumed silica adhering to the inner wall of the plastic container was then scraped off with a stirring rod and mixed into the mixture. The stirring rod was then rotated approximately 50 times to knead the entire mixture. The same sequence of mixing with the stirring / defoaming device, water cooling, and mixing with the stirring rod were repeated once more, and finally mixing with the stirring / defoaming device was performed to obtain Mixture B, consisting of polydimethylsiloxane containing vinyl groups at both ends and fumed silica modified with trimethylsilyl groups.

[0102] Next, 0.0110 g of platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex solution, 0.0100 g of 2,4,6,8-tetravinyl-2,4,6,8-tetramethylcyclotetrasiloxane, and 30.0 g of tetrahydrofuran as a viscosity modifier for the coating composition were weighed into a 100 ml glass bottle and stirring was initiated. Then, 10.00 g of Mixture B and 0.475 g of methylhydrogensiloxane-dimethylsiloxane copolymer were added and stirred for 5 minutes to obtain a coating composition with a solids concentration of 25.9 mass%. The calculated density (25°C) and measured viscosity (25°C) were 1004.3 kg / m, respectively. 3 , and 10.02 mPa s. The obtained coating composition was placed in a 50 ml glass bottle, and a syringe gasket of the same type as used in Example 1 was immersed in the composition and pulled up at a speed of 1.7 mm / s. A coating film was formed on the syringe gasket in the same manner as in Example 1, and a syringe was produced. The sliding resistance of the produced syringe was measured, and the initial sliding resistance, maximum sliding resistance, and sliding resistance increase rate were determined. The results are shown in Table 1.

[0103] Comparative Example 2 0.0080 g of platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex solution, 0.0075 g of 2,4,6,8-tetravinyl-2,4,6,8-tetramethylcyclotetrasiloxane, and 20.0 g of tetrahydrofuran were weighed into a 50 ml glass bottle and stirring was initiated. Then, 7.00 g of polydimethylsiloxane containing vinyl groups at both ends and 0.475 g of methylhydrogensiloxane-dimethylsiloxane copolymer were added and stirred for 5 minutes to obtain a coating composition with a solids concentration of 27.2 mass%. The calculated density (25°C) and measured viscosity (25°C) were 917.8 kg / m, respectively. 3 , and 6.24 mPa·s. A syringe gasket of the same type as that used in Example 1 was immersed in the obtained coating composition and pulled up at a speed of 2.4 mm / s, and a coating film was formed on the syringe gasket in the same manner as in Example 1, thereby producing a syringe. The sliding resistance of the produced syringe was measured, and the initial sliding resistance, maximum sliding resistance, and sliding resistance increase rate were determined. The results are shown in Table 1.

[0104] Comparing Examples 1 and 2 with Comparative Examples 1 and 2, it can be seen that Examples 1 and 2 have the effect of suppressing the initial sliding properties and maximum sliding resistance. Also, comparing Examples 1 and 2 with Comparative Examples 1 and 2, it can be seen that Examples 1 and 2 have the effect of suppressing the sliding resistance increase rate. While adding solid particles can suppress an increase in sliding resistance to some extent, adding too many solid particles increases the risk of them detaching from the sliding coating layer. The coating composition of the present invention can ensure sliding performance without relying on additives such as solid particles, and can suppress an increase in sliding performance. Furthermore, the coating composition of the present invention makes it possible to design coating agents with fewer additives. The coating composition of the present invention reduces the risk of additives and has excellent sliding performance and sliding performance consistency, providing an excellent sliding performance-imparting technology for fields such as syringes that require stable and consistent sliding resistance.

[0105] <Measurement of particle size of solid particles> Three drops (approximately 0.05 g) of the coating composition prepared in Example 1 and Comparative Example 1 were placed on a glass slide, covered with a cover glass, and air-dried overnight to volatilize the solvent. A transmission image of the dropped coating composition was then captured using an optical microscope (objective lens magnification: 50x), and the area of ​​each solid particle within the captured area (approximately 85 μm x approximately 113 μm) was measured. The area of ​​the solid particles was measured using the "Polygon" measurement function of the image analysis software HOZAN USB cam software 2 ver. 1.0, by drawing a hexagon along the outline of each solid particle and automatically measuring its area. Solid particles that were out of focus and therefore shaded were excluded from the measurement. Assuming that all solid particles were perfectly circular, the particle size was calculated from the area of ​​each solid particle, and the median diameter was calculated from the total particle size value. In Example 1 and Comparative Example 1, in which fumed silica modified with trimethylsilyl groups was added, the median diameters were 1.94 μm and 1.87 μm, respectively. Transmission images taken with an optical microscope are shown in Figures 3 and 4, and transmission images obtained by measuring the area of ​​the solid particles are shown in Figures 5 and 6.

[0106] [Table 1] [Industrial Applicability]

[0107] INDUSTRIAL APPLICABILITY The present invention relates to a composition that can impart slidability to structures such as syringes, and is industrially useful. [Explanation of symbols]

[0108] 1 syringe gasket A few ribs 4 Plunger connection 5 syringe barrels 6 Tip of tube 7 Plunger 8 Syringe gasket connection

Claims

1. A coating composition comprising a linear organopolysiloxane having an alkenyl group at one molecular end and a hydrogen group bonded to silicon at the other molecular end, and an organohydrogenpolysiloxane having at least two hydrogen groups bonded to silicon per molecule.

2. A coating composition comprising a linear organopolysiloxane having an alkenyl group at one molecular end and a hydrogen group bonded to Si at the other molecular end, A coating composition characterized in that the amount of alkenyl groups in the linear organopolysiloxane is 0.30 times or more and 1.0 times or less by mole based on the total number of unsaturated groups in the coating composition.

3. 3. The coating composition according to claim 2, further comprising an organohydrogenpolysiloxane having at least two silicon-bonded hydrogen groups per molecule.

4. 2. The coating composition according to claim 1, further comprising solid particles having a median diameter of 0.01 μm or more.

5. 3. The coating composition according to claim 2, further comprising solid particles having a median diameter of 0.01 μm or more.

6. 4. The coating composition according to claim 3, further comprising solid particles having a median diameter of 0.01 μm or more.

7. The coating composition according to any one of claims 1 to 6, which is a sliding coating composition.

8. 8. The coating composition of claim 7, further comprising an addition reaction catalyst.

9. A method for producing a structure having a coating layer, comprising a step of applying the coating composition according to claim 8 to a portion of the structure to which slidability is to be imparted, to form a slidable coating layer.

10. A structure having a coating layer formed by curing the coating composition according to claim 8.

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