(POLY)glycerin-based alkoxysilane-containing composition

Abstract

To provide an alkoxysilane-containing composition that is capable of curing a thick film and exhibits high hardness in the resulting film.SOLUTION: The foregoing problem is solved by a (poly)glycerin-based alkoxysilane-containing composition, comprising (A) a (poly)glycerin-based alkoxysilane having a (poly)glycerin skeleton with an average degree of polymerization of 1 to 100 and having an alkoxysilyl group, and (B) a hydrophilic filler.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an alkoxysilane-containing composition. [Background technology]

[0002] Polyfunctional alkoxysilane compounds such as ethyl silicate and methyltrimethoxysilane have already been commercialized as alkoxysilane-based coating compositions in combination with colloidal silica, methylolated melamine, polyvinyl alcohol, and the like.

[0003] Cured alkoxysilane films with a thickness exceeding 1 μm have the potential to be used as matrix materials for containing and dispersing optical materials such as UV-blocking and IR-blocking materials, or as hard-coating materials. However, conventional alkoxysilane cured films have large internal stresses during curing, making them prone to cracking, making it extremely difficult to produce cured films with a thickness exceeding 1 μm. Previous methods for producing silica films with a thickness exceeding 1 μm have included incorporating hydrophilic polymers such as polyvinylpyrrolidone (PVP) into the film or using alkoxysilanes with phenyl groups as starting materials, but the films produced by these methods have insufficient strength (Patent Document 1). In contrast, Non-Patent Document 1 proposes a cured film with a thickness exceeding 1 μm and excellent film strength by using a combination of 3-glycidoxypropyltrimethoxysilane (GPTMS) and tetraethoxysilane (TEOS). However, the thickness of the cured film was 1.2 μm, which is not significantly different from conventional film thicknesses. Curing to a thickness exceeding 1.2 μm has not been demonstrated, and thick film curing has not been fully achieved. Therefore, there is a need for a method for obtaining an alkoxysilane-containing composition that can be cured into a thick film and that can give a cured film with high hardness upon curing.

[0004] Furthermore, when obtaining a thick cured film, the affinity between the base resin and the filler is important. Because the filler has many hydroxyl groups on its surface, it is known that poor affinity between the base resin and the filler can cause aggregation or poor dispersion (Non-Patent Document 2). In particular, when curing a thick film, if the filler aggregates or poor dispersion occurs in the resin composition system before curing, the surface smoothness of the coating film deteriorates after curing, resulting in problems not seen in thin films, such as poor appearance, becoming more pronounced. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-145795 [Non-patent literature]

[0006] [Non-Patent Document 1] M.SAITO,NEW GLASS,Vol.24,No.3(2009) [Non-patent document 2] Kazuya Nagata, Journal of the Society of Rubber Science and Technology of Japan, Vol. 78, No. 6 (2005) Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide an alkoxysilane-containing composition that can be cured to form a thick film with high film hardness. [Means for solving the problem]

[0008] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by a (poly)glycerin-based alkoxysilane-containing composition characterized by containing (A) a (poly)glycerin-based alkoxysilane, which is a compound having a (poly)glycerin skeleton with an average degree of polymerization of 1 to 100 and has an alkoxysilyl group, and (B) a hydrophilic filler, and have thus completed the present invention. [Effects of the Invention]

[0009] The composition of the present invention can be cured by a general-purpose curing method to form a thick coating film, and a coating film with high hardness and smoothness can be obtained. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will be described below based on embodiments, but the scope of the present invention is not limited to these embodiments, and modifications made within the scope of the present invention also fall within the scope of the present invention. Note that the range indicated by "to" includes the upper and lower limits. Furthermore, "(poly)" indicates a monomer having a structure following (poly) and / or a multimer having two or more repeating units.

[0011] The present invention relates to a (poly)glycerin-based alkoxysilane-containing composition, characterized by containing a hydrophilic filler and a (poly)glycerin-based alkoxysilane having an alkoxysilyl group, which is a compound having a (poly)glycerin skeleton with an average degree of polymerization of 1 to 100.

[0012] The average degree of polymerization of the (poly)glycerol according to the present invention is 1 to 100, with a preferred lower limit of 2 or more, more preferably 4 or more, and a preferred upper limit of 70 or less, more preferably 20 or less, and most preferably 15 or less. The average degree of polymerization is calculated from the hydroxyl value determined by terminal analysis using the following formulas (I) and (II). The hydroxyl value in formula (II) is a numerical value that indicates the number of hydroxyl groups contained in the (poly)glycerol, and refers to the number of milligrams of potassium hydroxide required to neutralize the acetic acid required to acetylate the free hydroxyl groups contained in 1 g of the (poly)glycerol. The number of milligrams of potassium hydroxide is calculated in accordance with "Standard Testing Methods for the Analysis of Fats, Oils, and Related Materials, 2013 Edition," compiled by the Japan Oil Chemists' Society. Molecular weight=74n+18 (I) Hydroxyl value = 56110(n+2) / molecular weight (II)

[0013] The (poly)glycerin-based alkoxysilane according to the present invention is preferably a reaction product obtained by reacting (poly)glycerin or a (poly)glycerin derivative with a compound having an alkoxysilyl group.

[0014] The (poly)glycerin or (poly)glycerin derivative is preferably a compound represented by the structure of the following chemical formula (1).

[0015] [ka] (n, p, q, and r each represent the number of repeating units, n is an integer of 1 to 100, and p, q, and r each are integers of 0 to 50. AO represents an alkylene oxide having 1 to 4 carbon atoms. R1s are the same or different functional groups and are any reactive functional group selected from the group consisting of hydrogen, a thiol group, a (meth)acryloyl group, an epoxy group, and an allyl group, or a substituent containing such a functional group.)

[0016] Examples of AO include ethylene oxide (EO), propylene oxide (PO), and butylene oxide (BO), with ethylene oxide (EO) being preferred. p, q, and r in chemical formula (1) each represent the average number of alkylene oxides added to one hydroxyl group of polyglycerin, and each is preferably 0 to 50, more preferably 1 to 20. The sum of p, q, and r (p+q+r) is preferably 1 to 130, more preferably 5 to 120.

[0017] Specific examples of (poly)glycerin or (poly)glycerin derivatives include (poly)glycerin, (poly)glycerin alkylene oxide, (poly)glycerin-thioglycolic acid ester, (poly)glycerin alkylene oxide-thioglycolic acid ester, (poly)glycerin-3-mercaptopropionic acid ester, (poly)glycerin alkylene oxide-3-mercaptopropionic acid ester, (poly)glycerin-(meth)acrylate, (poly)glycerin alkylene oxide-(meth)acrylate, (poly)glycerin-(poly)glycidyl ether, (poly)glycerin alkylene oxide-(poly)glycidyl ether, (poly)glycerin-(poly)allyl ether, (poly)glycerin alkylene oxide-(poly)allyl ether, and the like.

[0018] The compound having an alkoxysilyl group is, for example, an alkoxysilane having a vinyl group, an allyl group, an isocyanate group, a thiol group, a (meth)acryloyl group, an epoxy group, a hydroxyl group, an amino group, a hydrosilyl group, or the like, and specifically, trimethoxysilane, triethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-isocyanatepropyltriethoxysilane, 3-isocyanatepropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, Examples of suitable silane include propyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-aminopropyltrimethoxysilane, 3-hydroxypropyltriethoxysilane, and 3-aminopropyltriethoxysilane.

[0019] The (poly)glycerin-based alkoxysilane of the present invention is preferably obtained by reacting the reactive functional group contained in (poly)glycerin or (poly)glycerin derivative with the reactive functional group contained in alkoxysilane.Specifically, for example, (poly)glycerin, (poly)glycerin alkylene oxide adduct, or (poly)glycerin derivative having thiol group, and the reaction product of the alkoxysilane containing any of vinyl group, isocyanate group, epoxy group, amino group, or the reaction product of the (poly)glycerin derivative having (meth)acryloyl group, or the (poly)glycerin derivative having allyl group, and the reaction product of the alkoxysilane containing any of vinyl group, allyl group, thiol group, (meth)acryloyl group, hydrosilyl group, or the reaction product of the (poly)glycerin derivative having epoxy group, and the reaction product of the alkoxysilane containing any of thiol group, hydroxyl group, hydrosilyl group, etc. In the resulting reaction product, it is preferable that 20 to 100% of the reactive functional groups of the (poly)glycerin or (poly)glycerin derivative are reacted and bonded, and it is more preferable that 50 to 100% of the reactive functional groups are reacted and bonded.

[0020] The hydrophilic filler used in the present invention is a filler having polar functional groups on its surface, such as inorganic fillers such as oxides and hydroxides, and organic fillers such as cellulose fiber. The hydrophilic filler interacts with the polyether structure of the (poly)glycerin-based alkoxysilane. This intermolecular interaction, primarily through hydrogen bonding, improves interfacial wettability, improves dispersibility, and provides benefits such as increased strength in the cured coating film.

[0021] The amount of the hydrophilic filler contained in the (poly)glycerin-based alkoxysilane-containing composition of the present invention is preferably 0.00025 to 20 parts by weight per 100 parts by weight of the (poly)glycerin-based alkoxysilane.

[0022] Examples of the hydrophilic inorganic filler used in the present invention include oxides such as silicon oxide, aluminum oxide, magnesium oxide, calcium oxide, cerium oxide, iron oxide, copper oxide, tin oxide, titanium oxide, zinc oxide, and zirconium oxide, hydroxides such as aluminum hydroxide and magnesium hydroxide, calcium carbonate, barium sulfate, ferrite, zeolite, and montmorillonite, and also include those that have been subjected to treatments such as particle surface modification.

[0023] Examples of hydrophilic organic fillers used in the present invention include cellulose derivatives such as carboxymethyl cellulose (CMC) and methyl cellulose; nanocelluloses such as cellulose nanofibers (CNF) and cellulose nanocrystals (CNC); conductive polymers such as PEDOT-PSS, polypyrrole, polyfuran, and polyaniline; biopolymers such as DNA, proteins, and lignin; polysaccharides such as xanthan gum and chitosan; starch and its derivatives, gelatin, polyvinyl alcohol (PVA), and cyclodextrin.

[0024] The cellulose fiber used in the present invention is obtained by pulverizing the raw material, natural cellulose. The method for pulverization is not particularly limited, and cellulose prepared by mechanical disintegration using a high-pressure homogenizer, a ball mill, or a high-pressure water jet can be used. The origin of the natural cellulose is also not particularly limited, and examples include those biosynthesized by plants, animals, and microorganisms. Specific examples include, but are not limited to, BiNFi-s (Sugino Machine Co., Ltd.), nanoforest-S (Chuetsu Pulp & Paper Co., Ltd.), and Celish (Daicel FineChem Co., Ltd.).

[0025] The method for preparing the (poly)glycerin-based alkoxysilane-containing composition of the present invention is not particularly limited, and examples thereof include a method of mixing a hydrophilic filler and a (poly)glycerin-based alkoxysilane using a dispersing device such as a mixer, ultrasonic disperser, paint shaker (rocking mill), ball mill, bead mill, or sand mill. When mixing, the hydrophilic filler may be dissolved in water and mixed in the form of an aqueous solution. Furthermore, beads such as zirconia beads and alumina beads may be used as needed.

[0026] The (poly)glycerin-based alkoxysilane-containing composition of the present invention can be used to prepare a cured coating film by applying it to various substrates and curing it. The method for curing the coating film is not particularly limited, but curing by a sol-gel reaction is preferred, for example.

[0027] When the (poly)glycerin-based alkoxysilane-containing composition of the present invention is cured by a sol-gel reaction, water is added as necessary for the hydrolysis of the metal alkoxide. It is also preferable to use a catalyst to promote the hydrolysis of the metal alkoxide and the polycondensation reaction. Examples of such catalysts include acid catalysts and alkali catalysts used in conventional sol-gel processes. Examples of acid catalysts include hydrochloric acid, nitric acid, sulfuric acid, formic acid, organic acids, and photoacid generators. Examples of alkali catalysts include inorganic base compounds such as metal hydroxides and ammonia, organic base compounds such as amines and phosphines, and photobase generators.

[0028] The coating method for producing a coating film using the (poly)glycerin-based alkoxysilane-containing composition of the present invention is not particularly limited, and examples thereof include cast coating, spin coating, blade coating, dip coating, roll coating, bar coating, and die coating.

[0029] The thickness of the coating film can be adjusted appropriately from 0.1 to 100 μm depending on the application. Generally, sol-gel films with a high proportion of inorganic components are considered difficult to form into films thicker than 1 μm due to the tendency for cracks to occur. However, the (poly)glycerin-based alkoxysilane-containing composition of the present invention allows for the formation of films thicker than 30 μm because the (poly)glycerin-based alkoxysilane has a flexible skeletal structure.

[0030] The (poly)glycerin-based alkoxysilane-containing composition of the present invention may contain other additives within the range that does not impair the effects of the present invention, such as ultraviolet absorbers, colorants, pigments, antioxidants, anti-yellowing agents, bluing agents, defoamers, thickeners, anti-settling agents, antistatic agents, surfactants, adhesion promoters, infrared absorbers, and light stabilizers.

[0031] Further, organic solvents may be mixed in. For example, alcohols include methanol, ethanol, butanol, isobutanol, isopropyl alcohol, propanol, t-butanol, sec-butanol, and benzyl alcohol; ketones include acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, cyclohexanone, and diacetone alcohol; esters include ethyl acetate, methyl acetate, butyl acetate, sec-butyl acetate, methoxybutyl acetate, amyl acetate, propyl acetate, isopropyl acetate, ethyl lactate, methyl lactate, and butyl lactate; ethers include isopropyl ether, methyl cellosolve, ethyl cellosolve, and butyl cellosolve; glycols include ethylene glycol, diethylene glycol, triethylene glycol, and propylene glycol; glycol esters include ethylene glycol monoethyl ether acetate and methoxy methyl ether acetate. Examples of suitable organic solvents include propyl acetate, butyl carbitol acetate, and ethyl carbitol acetate. Examples of suitable glycol ethers include diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, butyl diglycol, methyl triglycol, propylene glycol monomethyl ether (PGM), propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monobutyl ether, 3-methoxy-3-methyl-1-butanol, diethylene glycol monohexyl ether, propylene glycol monomethyl ether propionate, dipropylene glycol methyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, ethylene glycol diethyl ether, and diethylene glycol diethyl ether. Examples of suitable aromatic hydrocarbon solvents include benzene, toluene, and xylene. These organic solvents can be used alone or in combination of two or more.

[0032] In particular, in order to increase the crosslink density, for example, silicate monomers such as TMOS and TEOS, silicate oligomers such as methyl silicate and ethyl silicate, polysilsesquioxane, etc. may be blended.

[0033] Examples of substrates to which the (poly)glycerin-based alkoxysilane-containing composition of the present invention can be applied include glass, plastics such as polyethylene terephthalate, polycarbonate, and acrylic, metals, and stone.

[0034] The coating film produced by the (poly)glycerin-based alkoxysilane-containing composition of the present invention is used for coating, for example, automobile windshields, lamp covers, camera lenses, goggles, etc. Furthermore, since the coating film has bending resistance, it can be used for touch panel displays, electronic paper, organic EL lighting, substrate glass for solar cells, components for flexible devices, etc.

[0035] To apply the cured film of the (poly)glycerin-based alkoxysilane-containing composition of the present invention to these applications, it is necessary to adjust the formulations and additives depending on the application, but in the embodiment of the present invention, a pencil hardness of 3H or more is required. [Example]

[0036] The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

[0037] [Synthesis Example 1] A reaction vessel equipped with a thermometer and a stirrer was charged with 37 g of tetraglycerin EO 12 mole adduct, 63 g of 3-isocyanatepropyltriethoxysilane (manufactured by TCI), and 0.01 g of dibutyltin dilaurate, and the mixture was stirred at 60°C for 17 hours to obtain 100 g of alkoxysilane compound (A1). Note that 100% of the hydroxyl groups at the terminals of the polyglycerin derivative were reacted.

[0038] [Synthesis Example 2] A reaction vessel equipped with a thermometer and a stirrer was charged with 50 g of an EO 8 mole adduct of diglycerin, 86 g of 3-isocyanatepropyltriethoxysilane (manufactured by TCI), and 0.013 g of dibutyltin dilaurate, and the mixture was stirred at 60°C for 15 hours to obtain 131 g of alkoxysilane compound (A2). Note that 100% of the hydroxyl groups at the terminals of the polyglycerin derivative were reacted.

[0039] [Preparation of CNF aqueous dispersion] 0.0025 g to 1 g of CNF (BiNFi-s WFo-10005, manufactured by Sugino Machine) and 4 g to 4.9975 g of water were uniformly mixed with stirring to obtain a 0.0025 wt % to 1 wt % CNF aqueous dispersion.

[0040] Example 1 A coating solution was obtained by uniformly mixing 0.50 g of alkoxysilane compound (A1), 2.00 g of 1-methoxy-2-propanol, 0.35 g of water, 0.05 g of a 0.0025 wt% CNF aqueous dispersion, and 0.03 g of a 5 wt% aqueous nitric acid solution under stirring. The resulting mixture was then applied to a 1.3 mm thick glass plate (S9213, Matsunami Glass Industry Co., Ltd.) using an applicator (250 μm, Coating Tester Kogyo Co., Ltd.). The applied coating was air-dried at room temperature for at least 1 hour and then placed in a dryer (SPHH-101, Espec Co., Ltd.) set at 150 °C for 30 minutes to obtain a cured coating film with a thickness of 10 μm.

[0041] <Examples 2 to 6> A coating liquid and a cured coating film were prepared in the same manner as in Example 1, except that the 0.0025 wt % CNF dispersion used in Example 1 was changed to a 0.005 wt % to 1 wt % CNF dispersion.

[0042] Example 7 A coating solution was obtained by uniformly mixing 0.50 g of alkoxysilane compound (A2), 2.00 g of 1-methoxy-2-propanol, 0.33 g of water, 0.125 g of silica aqueous dispersion (PL-3, Fuso Chemical), and 0.03 g of 5 wt% aqueous nitric acid solution under stirring. The resulting mixture was then applied to a 1.3 mm thick glass plate (S9213, Matsunami Glass Industry) using an applicator (250 μm, Coating Tester Kogyo). The applied coating was air-dried at room temperature for over 1 hour and then placed in a dryer (SPHH-101, Espec) set at 150 °C for 30 minutes to obtain a cured coating film with a thickness of 10 μm.

[0043] <Examples 8 and 9> A coating liquid and a cured coating film were prepared in the same manner as in Example 7, except that the silica aqueous dispersion (PL-3, manufactured by Fuso Chemical) used in Example 7 was changed to a silica aqueous dispersion (PL-7, manufactured by Fuso Chemical) or a silica dispersion (PL-3-MA, manufactured by Fuso Chemical).

[0044] <Comparative Example 1> A coating solution was prepared by uniformly mixing 0.50 g of methyl silicate (MS-51, manufactured by Colcoat), 2.00 g of 1-methoxy-2-propanol, 0.88 g of water, 0.05 g of a 0.1 wt% CNF aqueous dispersion, and 0.03 g of a 5 wt% aqueous nitric acid solution under stirring. The resulting mixture was then applied to a 1.3 mm thick glass plate (S9213, manufactured by Matsunami Glass Industry) using an applicator (250 μm, manufactured by Coating Tester Kogyo). The applied coating was air-dried at room temperature for over 1 hour and then placed in a dryer (SPHH-101, manufactured by Espec) set at 150 °C for 30 minutes. Although the coating cured, cracks developed throughout the entire coating, causing it to peel off from the glass substrate, resulting in no coating.

[0045] <Comparative Example 2> A coating solution was prepared by uniformly mixing 4.00 g of silicate oligomer, 0.05 g of a 0.1 wt% CNF aqueous dispersion, and 0.03 g of a 5 wt% nitric acid aqueous solution under stirring until the alkoxysilane content was as shown in Table 1. The resulting mixture was then applied to a 1.3 mm thick glass plate (S9213, Matsunami Glass Industry Co., Ltd.) using an applicator (250 μm, Coating Tester Kogyo Co., Ltd.). The applied coating was air-dried at room temperature for over 1 hour and then placed in a dryer (SPHH-101, Espec Co., Ltd.) set at 150 °C for 30 minutes. Although the coating cured, cracks developed throughout the entire coating, causing it to peel off from the glass substrate, resulting in no coating.

[0046] <Comparative Example 3> A coating liquid and a cured coating film were prepared in the same manner as in Examples 1 to 6, except that the CNF dispersion was not added.

[0047] <Comparative Example 4> Coating solutions and cured coating films were prepared in the same manner as in Examples 7 to 9, except that the silica dispersion was not added.

[0048] The surface condition of the cured coating films of Examples 1 to 9 and Comparative Examples 3 and 4 was evaluated by touch. <Judgment criteria> 〇: The coating film is smooth and not rough when touched with a finger. ×: The coating film is rough when touched with a finger, or is not smooth.

[0049] The hardness of the cured coating films of Examples 1 to 9 and Comparative Examples 3 and 4 was evaluated by the following pencil hardness. (Pencil hardness) The evaluation was carried out in accordance with JIS K5600-5-4 using a coating hardness tester (Bevs1301 / 750, manufactured by Bevs) under a load of 750 g.

[0050] The results for Examples 1 to 9 and Comparative Examples 1 to 4 are shown in Table 1 below.

[0051] [Table 1]

[0052] Generally, sol-gel films with a high proportion of inorganic components are prone to cracking when formed into thick films of 1 μm or more, and so it was not possible to obtain a cured film with the alkoxysilanes not containing a (poly)glycerin structure in Comparative Examples 1 and 2. In contrast, the compositions of Examples 1 to 9, consisting of an alkoxysilane containing a (poly)glycerin structure and a hydrophilic filler, were able to form a cured film of 10 μm, and the hardness was 3H, suggesting the possibility of application to the uses and fields described in paragraph

[0034] . The surface of the coating film was smooth and not rough, indicating that filler aggregation was suppressed.

Claims

1. A (poly)glycerin-based alkoxysilane-containing composition characterized by containing the following components (A) and (B): (A) A (poly)glycerin-based alkoxysilane having an alkoxysilyl group, which is a compound having a (poly)glycerin skeleton and an average degree of polymerization of 1 to 100. (B) Hydrophilic filler

2. 2. The (poly)glycerin-based alkoxysilane-containing composition according to claim 1, wherein the ratio of components (A):(B) is 100:0.00025 to 100:20.

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