JP7544371B2 - Film, anti-fogging film, hard coat film and method for producing film - Google Patents

Description

The present invention relates to a film, an anti-fogging film, a hard coat film, and a method for producing the film.

Fogging refers to a state in which numerous fine water droplets on the surface of glass, mirrors, etc. cause light to be diffusely reflected, preventing the normal passage or reflection of light. Anti-fogging technology to prevent fogging is widely used in automobile window glass, show windows, eyeglasses, goggles, helmets, food packaging, medical equipment, etc. The main anti-fogging technologies used are a method of making the substrate surface hydrophobic or water-repellent with a hydrophobic polymer, etc., so that water droplets themselves do not easily adhere to the substrate, and a method of making the substrate surface hydrophilic, forming a thin, continuous water film.

Coating the substrate surface with a hydrophobic polymer has the disadvantage of insufficient adhesion to inorganic substrates such as glass. For this reason, the mainstream anti-fogging film material is coating the substrate surface with a hydrophilic polymer. However, many hydrophilic polymers, such as polyvinyl alcohol (PVA), are soft, and their transparency and anti-fogging properties gradually decrease due to scratches or abrasion.

Silsesquioxane (SQ) is a siloxane compound having a repeating structure of RSiO _1.5 (R is an organic group or H) obtained by hydrolysis/condensation reaction of trifunctional organosilane compounds such as organic trialkoxysilane and organic trichlorosilane. Various structures such as random type, cage type (polyhedron), ladder type, etc. are known as SQ structures. Cage-type oligo SQ has a structure in which a ring is closed three-dimensionally by siloxane bonds. Cage-type oligo SQ has a polyhedral skeleton structure, and has a structure in which silicon atoms are arranged at the vertices and siloxane bonds are arranged at the edges. Cage-type oligo SQ is also called polyhedral oligo SQ, and is also abbreviated as POSS (polyhedral oligomeric silsesquioxane).

A polymer containing POSS in its main chain is a material with greater thermal stability and strength because the hard inorganic skeleton of POSS directly contributes to improving the rigidity of the polymer. For example, Patent Document 1 discloses a hydrophilic coating film that contains 0.001% by mass or more of POSS.

JP 2010-275541 A

Patent Document 1 does not consider the anti-fogging properties of coating films containing the above-mentioned POSS. There is a demand for anti-fogging materials that are scratch-resistant and durable due to their hardness, as well as have high anti-fogging properties.

The present invention has been made in consideration of the above circumstances, and aims to provide a film, an anti-fogging film, a hard coat film, and a method for producing the film that has high hardness and can provide high anti-fogging properties.

Since POSS is an oligomer, it is difficult to use POSS alone as a film or bulk material. Therefore, the synthesis of polymers containing POSS has been investigated. However, since POSS has multiple organic groups in its side chains, it often forms a network structure through polymerization, and can become insoluble. When it becomes insoluble, molding processing becomes difficult. After extensive research, the inventors discovered that a film made of a soluble polymer containing POSS exhibits high hardness and high anti-fogging properties when subjected to heat treatment, and thus completed the present invention.

The membrane according to the first aspect of the present invention comprises:
The polymer includes a first substituent carried by a first polyhedral oligosilsesquioxane and a second substituent carried by a second polyhedral oligosilsesquioxane,
the first substituent has an ammonium group ;
The second substituent has a carboxyl group .

The anti-fogging film according to the second aspect of the present invention comprises:
The polymer includes a first substituent carried by a first polyhedral oligosilsesquioxane and a second substituent carried by a second polyhedral oligosilsesquioxane,
the first substituent has an ammonium group ;
The second substituent has a carboxyl group .

The hard coat film according to the third aspect of the present invention comprises:
The polymer includes a first substituent carried by a first polyhedral oligosilsesquioxane and a second substituent carried by a second polyhedral oligosilsesquioxane,
the first substituent has an ammonium group ;
The second substituent has a carboxyl group .

A method for producing a membrane according to a fourth aspect of the present invention comprises the steps of:
a bonding step of reacting a first substituent carried by the first polyhedral oligosilsesquioxane with a second substituent carried by the second polyhedral oligosilsesquioxane;
a heating step of heating the polymer obtained in the bonding step to 100° C. or higher;
Including,
the first substituent has an ammonium group ;
The second substituent has a carboxyl group .

In this case, in the heating step,
heating the polymer to at least 100° C. and less than 160° C.;
This may also be the case.

The present invention provides high hardness and high anti-fogging properties.

FIG. 2 shows a reaction in a bonding step according to an embodiment of the present invention. FIG. 1 is a diagram showing the results of Fourier transform infrared spectroscopy (FTIR) in an example. FIG. 2 shows the ¹ H NMR spectrum of the product according to the example. FIG. 2 shows the ²⁹ Si NMR spectrum of the product according to the example.

The following describes an embodiment of the present invention with reference to the drawings. Note that the present invention is not limited to the following embodiment and drawings.

(Embodiment)
The film according to the present embodiment includes a polymer in which a substituent A (first substituent) of the first POSS is bonded to a substituent B (second substituent) of the second POSS. The first POSS and the second POSS are not particularly limited as long as they have a polyhedral skeleton structure. The first POSS and the second POSS may be, for example, a _T6 structure in which the number of silicon atoms arranged at the vertices of the polyhedron is 6, a _T7 structure in which the number of silicon atoms arranged at the vertices of the polyhedron is 7, a _T8 structure in which the number of silicon atoms arranged at the vertices of the polyhedron is ₈ , a _T10 structure in which the number of silicon atoms arranged at the vertices of the polyhedron of the first POSS may be the same or different.

The first POSS or the second POSS may have the same or different number of silicon atoms. For example, the first POSS may have a mixture of POSS with _T8 structure and POSS with _T10 structure. The second POSS may have a mixture of POSS with _T8 structure, POSS with _T10 structure and POSS with _T12 structure.

The first POSS and the second POSS have a substituent A and a substituent B as side chains, respectively. The functional group of the substituent A reacts with the functional group of the substituent B to bond, thereby linking the first POSS and the second POSS. The reaction between the functional group of the substituent A and the functional group of the substituent B may be a condensation reaction or an addition reaction. Examples of functional groups include an amino group, an ammonium group, a mercapto group, a hydroxyl group, a carboxyl group, an aldehyde group, a ketone group, an epoxy group, a vinyl group, an acrylate group, and a methacrylate group.

At least one of the substituent A and the substituent B has a hydrophilic functional group. Preferably, both the substituent A and the substituent B have a hydrophilic functional group. The hydrophilic functional group is, for example, a functional group that ionizes in water to become an ion, and a functional group that hydrates by hydrogen bonding. Examples of the hydrophilic functional group include a hydroxyl group, a carboxyl group, and an amino group. For example, when the substituent A has a hydroxyl group, the substituent B has a carboxyl group that forms an ester bond by dehydration condensation with the hydroxyl group. When the substituent A has an amino group, the substituent B has a carboxyl group that forms an amide bond by dehydration condensation with the amino group. When the substituent A has an amino group, the substituent B may have an aldehyde group. Preferably, the substituent A has an ammonium group, and the substituent B has a carboxyl group.

One or both of the substituent A and the substituent B may have multiple types of functional groups. In this case, for example, the substituent A has an amino group and a mercapto group, and the substituent B has a carboxyl group. In addition, the substituent A may have two ammonium groups, and the substituent B may have two carboxyl groups.

The molar unit ratio of the first POSS and the second POSS in the polymer according to the present embodiment is not particularly limited, and is, for example, 9:1, 7:3, 4:1, 3:2, 1:1, 2:3, 1:4, 3:7, or 1:9. Preferably, the molar unit ratio of the first POSS and the second POSS is 1.5 to 1:1, 1.3 to 1:1, 1.2 to 1:1, 1:1.5 to 1, 1:1.3 to 1, or 1:1.2 to 1. Suitably, the molar unit ratio of the first POSS and the second POSS is 1:1. The molar unit ratio of the first POSS and the second POSS in the polymer can be determined by known structural analysis methods, for example, by measuring NMR spectra such as ¹ H and ²⁹ Si.

Next, a method for producing a film according to the present embodiment will be described. The method for producing the film includes a bonding step and a heating step. In the bonding step, a reaction is carried out to bond the substituent A of the first POSS with the substituent B of the second POSS.

When substituent A and substituent B are bonded by a condensation reaction, the bonding step may involve mixing and stirring the first POSS, the second POSS and the condensation agent. In the bonding step, when an amino group and a carboxyl group are condensed to form an amide bond, examples of the condensing agent include carbodiimide-based condensing agents such as EDC (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride), DCC (N,N'-dicyclohexylcarbodiimide), 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide and N,N'-diisopropylcarbodiimide, imidazole-based condensing agents such as N,N'-carbonyldiimidazole and 1,1'-carbonyldi(1,2,4-triazole), diphenylphosphoryl azide (DPPA), and triazole-based condensing agents such as 2-chloro-4,6-dimethoxy-1,3,5-triazine (CDMT), triazine-based condensing agents, phosphonium-based condensing agents, uronium-based condensing agents, haluronium-based condensing agents, and N-hydroxysuccinimide (NHS). A promoter may be used in the binding step. The condensation agent may also serve as the promoter. Any organic solvent may be used as the solvent in the binding step. For example, the solvent is preferably dimethyl sulfoxide (DMSO), particularly dehydrated DMSO.

The reaction conditions for the binding step are set appropriately. For example, the reaction temperature is 40 to 120°C, 60 to 100°C, or 70 to 90°C. The reaction time is adjusted according to the reaction rate, and is, for example, 1 to 24 hours, 3 to 20 hours, 6 to 18 hours, 8 to 16 hours, or 10 to 14 hours.

Preferably, the polymer obtained in the binding step may be isolated, purified, and concentrated by known methods. For example, the polymer may be obtained through operations such as reprecipitation, decantation, filtration, washing, and concentration.

FIG. 1 shows a specific example of the reaction in the bonding step. The first POSS and the second POSS are POSS-A and POSS-C, respectively. POSS-A is a POSS of _T8 structure and a POSS of _T10 structure having an ammonium group as a functional group in the substituent R. POSS-A is a salt of trifluoromethanesulfonic acid (HOTf). POSS-C is a POSS of _T8 structure, a POSS of _T10 structure, and a POSS of _T12 structure having a carboxyl group as a functional group in the substituent R. The ammonium group of POSS-A and the carboxyl group of POSS-C are polycondensed using a condensing agent to synthesize a soluble polymer (POSS polyamide) in which POSS-A and POSS-C are linked via an amide bond.

In the heating step, the polymer obtained in the bonding step is heated to 100°C or higher. The heating temperature is set according to the properties of the obtained polymer. For example, the heating temperature is 100 to 200°C, 100 to 180°C, 100 to 160°C, 100 to 150°C, or 100 to 140°C. Considering the anti-fogging properties and hardness of the film, the heating temperature is preferably 100°C or higher and less than 160°C. The heating time is, for example, 5 to 60 minutes, 10 to 50 minutes, or 20 to 40 minutes.

Preferably, in the heating step, the polymer is heated on the substrate on which the film is to be formed. In this case, the substrate on which the polymer solution is applied is heated. The solvent of the polymer solution is not particularly limited. Since at least one of the substituent A and the substituent B has a hydrophilic functional group, the polymer is soluble in water, etc. As the solvent, in addition to water, alcohols such as methanol, ethanol, and isopropyl alcohol, DMSO, N,N-dimethylformamide (DMF), or mixtures thereof may be used.

The polymer concentration of the polymer solution is adjusted as appropriate, and may be, for example, 10 to 1000 g/L, 50 to 800 g/L, 100 to 600 g/L, 150 to 400 g/L, or 200 to 300 g/L.

The substrate is not particularly limited as long as the polymer can form a film, preferably a thin film. Examples of the substrate material include inorganic materials and organic materials. Inorganic materials include nonmetallic inorganic materials and metallic inorganic materials. Examples of nonmetallic inorganic materials include glass and ceramic materials. Examples of metallic inorganic materials include cast iron, steel, iron, iron alloys, aluminum, aluminum alloys, nickel, nickel alloys, and zinc die-casting. The metallic inorganic material may also be a metal plating film applied to the surface of a nonmetallic inorganic material or an organic material.

Examples of organic materials include synthetic resin materials such as polyvinyl chloride resin, polyethylene, polypropylene, polycarbonate, acrylic resin polyacetal, fluororesin, silicone resin, ethylene-vinyl acetate copolymer (EVA), acrylonitrile-butadiene rubber (NBR), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyvinyl butyral (PVB), ethylene-vinyl alcohol copolymer (EVOH), polyimide, polyphenylene sulfide (PPS), polyetherimide (PEI), polyetheretherimide (PEEI), polyetheretherketone (PEEK), melamine resin, and acrylonitrile-butadiene-styrene (ABS) resin, as well as fiber materials.

A known method can be used to apply the polymer solution to the substrate. Specifically, the polymer solution can be applied to the substrate using a solution casting method, a dip coating method, a spin coating method, a spray coating method, a brush coating method, an impregnation method, a roll method, a wire bar method, a die coating method, a gravure printing method, an inkjet method, or the like. The thickness of the film is not particularly limited, but is, for example, 1 nm to 1 mm, 10 nm to 500 μm, or 100 nm to 50 μm.

As shown in the following examples, the film according to the present embodiment has excellent transparency and high antifogging properties. Antifogging properties can be evaluated by various known methods. For example, as specified in the JIS standard, there is a method of visually checking the presence or absence of fogging under specified conditions (JIS K2399, JIS S7027/S7301 and JIS A1514). Antifogging properties can be evaluated based on the transmittance of laser light as in the EN standard (EN168). In addition, antifogging properties can be evaluated using a commercially available antifogging evaluation device using the natural condensation method and the humidified injection method, or visual tests such as breath antifogging tests, steam antifogging tests and low-temperature antifogging tests, as well as image analysis.

The film according to the present embodiment includes a polymer having POSS as the main chain, and therefore has the rigidity of POSS. Therefore, the film has high hardness. The hardness of the film can be evaluated by a known method. The hardness can be evaluated by an indentation test method or a dynamic test method. The hardness is indicated by Rockwell hardness, Vickers hardness, Brinell hardness, Shore hardness, Knoop hardness, etc. based on the test method. An example of a hardness that can be easily evaluated is pencil hardness. The pencil hardness can be evaluated by a known tester such as a pencil scratch tester. The hardness of the film according to the present embodiment is 2H or more or 3H or more, preferably 5H or more or 5H, in terms of pencil hardness.

The film according to the present embodiment has both high hardness and anti-fogging properties, and can therefore be used as an anti-fogging film that is scratch-resistant and highly durable. In addition, the film is useful as a hard coat film that protects the substrate from external factors.

The present invention will be explained in more detail with reference to the following examples, but the present invention is not limited to these examples.

(Synthesis of POSS-A)
The above POSS-A was synthesized as follows according to a previous report (Yoshiro Kaneko and two others, "Preparation of cage-like octa(3-aminopropyl) silsesquioxane trifluoromethanesulfonate in higher yield with a shorter reaction time", Journal of Materials Chemistry, 2012, 22, 14475-14478). 200 mL of HOTf aqueous solution (0.50 mol/L, 100 mmol) was added as a catalyst and solvent to 3-aminopropyltrimethoxysilane (APTMS) (33.3 mmol, 6.225 g), stirred at room temperature for 2 hours, and the solvent was distilled off by heating in an open system (about 50° C.). Then, the mixture was heated in an oven at 100° C. for 2 hours. Approximately 200 mL of acetone:chloroform = 1:1 (v/v) was added to the obtained powdery crude product, and the insoluble portion was collected by suction filtration using a membrane filter (pore size = 0.2 μm), washed with acetone:chloroform = 1:1 (v/v) (approximately 50 mL x 3 times), and dried under reduced pressure to obtain _a white solid product (POSS-A) (yield: 92%; calculated using the chemical formula of the repeating unit [ _SiO1.5 ( _CH2 ) _3NH3 ⁺ _{CF3SO3- ,} FW = 260.26] ⁾ .

(Synthesis of POSS-C)
The above POSS-C was synthesized as follows according to a previous report (Tomoya Kozuma and one other person, "Preparation of carboxyl-functionalized polyhedral oligomeric silsesquioxane by a structural transformation reaction from soluble rod-like polysilsesquioxane", Journal of Polymer Science Part A: Polymer Chemistry, 2019, 57, 2511-2518). 100 mL of HOTf aqueous solution (0.50 mol/L, 50 mmol) was added as a catalyst and solvent to carboxyl group-containing rod-shaped polysilsesquioxane (PolySQ-COOH, 33.3 mmol units, 4.172 g), and the aqueous solution obtained by heating at about 60° C. for 10 minutes was stirred at room temperature for 2 hours, and the solvent was distilled off by heating in an open system (about 50° C.). Then, it was heated in an oven at 100° C. for 2 hours. The obtained liquid crude product was cooled to room temperature, acetone (8.40 mL) was added, and the obtained solution was poured into acetone:chloroform=1:9 (v/v, 416 mL) and stirred at 1000 rpm for 15 hours at room temperature.

Next, the insoluble portion was collected by suction filtration using a membrane filter (pore size = 0.2 μm), washed with acetonitrile (about 25 mL x 5 times), and dried under reduced pressure to obtain a white solid product (POSS-C) (yield: 32%; calculated using the chemical formula of the repeating unit [SiO _1.5 (CH ₂ ) ₂ COOH, FW = 125.15]). PolySQ-COOH was prepared by preparing 2.0 mol/L of 2-cyanoethyltriethoxysilane (CETES) as a raw material in accordance with a previously reported method (see JP 2013-170175 A and H. Toyodome and 3 others, “Preparation of carboxylate group-containing rod-like polysilsesquioxane with hexagonally stacked structure by sol-gel reaction of 2-cyanoethyltriethoxysilane”, Polymer, 2012, 53, Issue 26, 6021-6026). It was synthesized by hydrolysis/condensation reaction in aqueous NaOH solution.

(Synthesis of POSS polyamide)
POSS polyamide was synthesized by the reaction shown in Figure 1 as follows. POSS-A (10 mmol units, 2.603 g), EDC (15 mmol, 2.934 g), and a solution prepared by adding dehydrated DMSO (150 mL) to NHS (15 mmol, 1.817 g) were added to a solution prepared by adding dehydrated DMSO (150 mL) to POSS-C (10 mmol units, 1.252 g), and the mixture was stirred at about 80°C for 12 hours. Thereafter, the reaction solution was added to acetone (about 2000 mL) to perform reprecipitation, and the mixture was stirred at room temperature for 2 hours.

The resulting viscous solid crude product was separated by decantation, methanol (30 mL) was added, and the resulting solution was added to acetone (approximately 1000 mL) to perform reprecipitation. The resulting powdery crude product was collected by suction filtration using a membrane filter (pore size = 0.2 μm) and washed with acetone (approximately 25 mL x 5 times). Next, DMF (40 mL) at approximately 80°C was added to the crude product and stirred at approximately 80°C for 15 minutes, after which the soluble portion was collected by suction filtration and concentrated (approximately 2 mL) using a rotary evaporator.

The concentrated solution was then added to acetone (about 60 mL) to effect reprecipitation, and the resulting powdery product was collected by suction filtration, washed with acetone (about 25 mL x 5 times), and dried under reduced pressure to obtain a white solid product (POSS polyamide) (yield: 18%; the yield was calculated from the average formula weight of the repeating units [FW = 147.58]. This average formula weight of the repeating units is the chemical formula of the repeating units, ammonium units [ _SiO1.5 ( _CH2 ) _3NH3 ^{+ Cl-} , FW = 146.65], carboxyl units [ _SiO1.5 ( _{CH2 ) 2COOH} , FW = 125.15], and amide units [ _SiO1.5 ( _CH2 ) _3NHCO ( _{CH2 ) 2SiO1.5} , FW=217.33] (composition ratio of ammonium-carboxyl-amide units=40:45:15)).

(Structural Analysis)
The sample for FTIR measurement was prepared as follows: Two to three spatulas of KBr (potassium bromide) for infrared absorption measurement and an amount of the product that adhered to the tip of the spatula were thoroughly ground in an agate mortar, and pressed into pellets using a tablet molder to prepare the measurement sample.

The FTIR spectrum was measured using an FTIR-4200 spectrometer (manufactured by JASCO Corporation) with a resolution of 16 cm ⁻¹ and 16 accumulations.

The sample for ¹ H NMR measurement was prepared as follows: 0.4 spatula spoonful of the product was added to DMSO-d ₆ (0.50 mL) and stirred to dissolve the product, which was used as the measurement sample. The sequence was single pulse (no decoupling) and the number of accumulations was 8.

The sample for measuring ^29Si NMR was prepared as follows. The product (0.120g) and tris(2,4-pentanedionato)chromium(III) (Cr(acac) ₃ ) or chromium(III) chloride hexahydrate (0.0063g) were added to DMSO- _d6 (0.50mL) and stirred to dissolve, and the solution was used as the measurement sample. Just before the measurement, 5 drops of tetramethylsilane were added, the container was covered with parafilm, and shaken thoroughly. The measurement temperature was 40°C, the sequence was single pulse (no decoupling), and the number of accumulations was 1000.

¹ H NMR and ²⁹ Si NMR spectra were measured using an ECX-400 spectrometer (manufactured by JEOL RESONANCE).

(result)
When the product was subjected to FTIR measurement, as shown in FIG. 2, an absorption peak derived from an amide bond was observed at 1631 cm ⁻¹ , which was not observed in the starting material.

As shown in Figure 3, the ^1H NMR spectrum of the product in DMSO-d ₆ showed signals derived from the side chains of the starting materials POSS-A and POSS-C, as well as a signal i derived from the methylene proton adjacent to the N atom of the amide bond, confirming the formation of the amide bond.

The number of amide bonds bound to POSS-C was calculated from the abundance ratio of each POSS in the starting material POSS-C ( _T8 structure: _T10 structure: _T12 structure=15:64:21) and the integral ratio of signals d and g (2.00:5.93), suggesting that an average of 2 amide bonds are formed when POSS-C is an octamer, an average of 2.5 amide bonds are formed when POSS-C is a decamer, and an average of 3 amide bonds are formed when POSS-C is a dodecamer. On the other hand, the number of amide bonds bound to POSS-A was calculated from the abundance ratio of each POSS in the starting material POSS-A ( _T8 structure: _T10 structure=82:18) and the integral ratio of signals d and e (2.00:5.18), suggesting that an average of 2.2 amide bonds are formed when POSS-A is an octamer, and an average of 2.8 amide bonds are formed when POSS-A is a decamer. From the above, it is presumed that the reason a soluble polymer was obtained is that there were relatively few amide bonds per POSS, an average of 2 to 3, so a network structure was not formed, and the POSS were linked in a somewhat linear chain shape.

Furthermore, the repeat unit ratio of POSS-C to POSS-A was calculated from the integral ratio of signals g and e (2.00:1.75) to be 53:47, which was found to be almost the same value as the repeat unit ratio of POSS (1:1) in each of the raw materials charged. Furthermore, from this unit ratio and the abundance ratio of each POSS in the starting materials POSS-C and POSS-A, the composition ratio of the 8-, 10-, and 12-mer units of POSS-C and the 8- and 10-mer units of POSS-A in the POSS polyamide was estimated to be 8.0:33.9:11.1:38.5:8.5.

As shown in Figure 4, the ^29Si NMR spectrum of the product showed no signal in the ^T2 region (CSi(OSi) _n (OH) _3-n , n=2) and only a signal in the ^T3 region (CSi(OSi) _n (OH) _3-n , n=3). This indicates that the POSS structure is maintained even after polycondensation.

(Investigation of self-supporting film forming ability)
The product was dissolved in methanol, applied onto a polypropylene disposable tray, and the solvent was distilled off by heating in an open system (about 50° C.).

(result)
A free-standing film was formed with POSS polyamide. On the other hand, POSS-A became a powdery solid. POSS-C became a sticky solid. POSS-A and POSS-C did not form a free-standing film.

(Solubility Study)
The solubility of the product was investigated in the following solvents: water, DMSO, DMF, methanol (MeOH), acetone ( _Me2CO ), ethyl acetate (AcOEt), chloroform ( _CHCl3 ), toluene and hexane.

(result)
The solubility results are shown in Table 1, where "+" and "-" indicate soluble and insoluble, respectively, at room temperature. POSS polyamides were shown to be soluble in highly polar solvents such as water, DMSO, DMF, and MeOH.

(Preparation of cast film of POSS polyamide)
An aqueous solution prepared by dissolving 25 mg of POSS polyamide in 0.10 mL of water was applied onto a mineral glass substrate whose surface had been polished with cerium oxide (surface area: approximately 1.76 cm ² ).The solvent was then removed by heating in an open system (approximately 50° C.), and the substrate was then heated in an oven at 100 to 200° C. for 30 minutes (heat treatment) to produce a cast film of POSS polyamide.

Hardness was measured using a pencil scratch tester (TP Giken, 750 g) in accordance with JIS K5600-5-4. The tip of a pencil (uni, Mitsubishi Pencil Co., Ltd.) was sharpened flat, and the pencil was attached to the tester so that the angle of the pencil to the cast film was 45 degrees. The pencil was moved at a speed of 0.5 to 1 mm/s. The pencil hardness, which was the hardest pencil that did not produce a scratch, was evaluated as the hardness.

Anti-fogging properties were evaluated by placing the cast film face down about 5 cm above hot water at about 80°C and exposing it to water vapor.

(result)
The hardness of the cast film and the presence or absence of anti-fogging properties are shown in Table 2. Both cast films of POSS polyamide before and after heat treatment were transparent. The hardness of the cast film was 2H or more when heat-treated at 100°C or higher, and was 5H or more when heat-treated at 150°C or higher. In addition to the rigidity of POSS, the amide bond was increased after heat treatment, forming a cross-linked structure, so the cast is considered to have a high hardness.

The cast films obtained by heat treatment at 100°C or 150°C showed anti-fogging properties. The cast films obtained by heating at 150°C showed anti-fogging properties for about 5 seconds after exposure, became foggy about 5 to 35 seconds, and after about 35 seconds became transparent again and showed anti-fogging properties. On the other hand, the cast films obtained by heating at 160 to 200°C did not show anti-fogging properties.

The above-described embodiment is intended to explain the present invention, and does not limit the scope of the present invention. In other words, the scope of the present invention is indicated by the claims, not by the embodiment. Furthermore, various modifications made within the scope of the claims and within the scope of the meaning of the invention equivalent thereto are considered to be within the scope of the present invention.

The present invention is suitable for imparting anti-fogging properties to automobile window glass, show windows, eyeglasses, goggles, helmets, food packaging, medical equipment, etc.

Claims (5)

The polymer includes a first substituent carried by a first polyhedral oligosilsesquioxane and a second substituent carried by a second polyhedral oligosilsesquioxane,
the first substituent has an ammonium group;
the second substituent has a carboxyl group;
film. The polymer includes a first substituent carried by a first polyhedral oligosilsesquioxane and a second substituent carried by a second polyhedral oligosilsesquioxane,
the first substituent has an ammonium group;
the second substituent has a carboxyl group;
Anti-fog membrane. The polymer includes a first substituent carried by a first polyhedral oligosilsesquioxane and a second substituent carried by a second polyhedral oligosilsesquioxane,
the first substituent has an ammonium group;
the second substituent has a carboxyl group;
Hard coat film. a bonding step of reacting a first substituent carried by the first polyhedral oligosilsesquioxane with a second substituent carried by the second polyhedral oligosilsesquioxane;
a heating step of heating the polymer obtained in the bonding step to 100° C. or higher;
Including,
the first substituent has an ammonium group;
the second substituent has a carboxyl group;
Method for producing the membrane. In the heating step,
heating the polymer to at least 100° C. and less than 160° C.;
A method for producing the membrane according to claim 4 .