JP2008255192A - Coating liquid for forming anti-fogging film, anti-fogging film and method for forming anti-fogging film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an anti-fogging film with improved hardness and wear resistance by utilizing an anti-fogging urethane resin and to provide a coating liquid for forming anti-fogging film. <P>SOLUTION: The coating liquid for forming anti-fogging film is prepared from three kinds of materials for preparation, wherein the materials comprise a material (I) containing a reaction product (A) of an isocyanate component having isocyanate groups and a water absorbing polyol with 400-5,000 of number average molecular weight, a material (II) containing a hydrolysis polycondensate (B) of a plurality of silicon oxide precursors (b), and a material (III) containing metal oxide fine particles (C), and containing 25-40 wt.% of the reaction product (A), 21-50 wt.% of the hydrolysis polycondensate (B) and 25-45 wt.% of the metal oxide fine particles (C) in the sum of the reaction product (A), the hydrolysis polycondensate (B) and the metal oxide fine particles (C), and the plurality of the silicon oxide precursors (b) contain 14-27 wt.% of tetraalkoxysilane (b1), 14-27 wt.% of a trialkoxysilane containing alkyl group (b2) and 46-72 wt.% of trialkoxysilane (b3) containing at least one group in the group consisting of an epoxy group, a mercapto group and an amino group. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to an antifogging film-forming coating solution, an antifogging film, and a method for forming an antifogging film. In particular, an antifogging film-forming coating solution that can be suitably used as a window glass for a room having a mechanism capable of controlling humidity, such as an air conditioner, for example, a room of an automobile, and the antifogging The present invention relates to a method for forming an antifogging film using a coating solution for forming an antifogging film and an antifogging film formed by the method.

Transparent substrates such as glass are used for vehicle window glass, architectural window glass, lenses, goggles and the like. However, when the glass is used in a humid place or at a boundary with a large temperature difference, fogging occurs. The cloudiness occurs when the glass has a temperature lower than the dew point in the atmosphere, and water vapor in the atmosphere condenses to cause condensation on the surface, and light condensation occurs due to the condensed water droplets. For example, when a vehicle is driven during a rainy season with high humidity or in winter when the temperature is low, fogging of the window is inevitable, and dehumidified air such as warm air and cold air is blown through the window to ensure visibility. Usually, it is made dry.

Therefore, the energy consumed for securing the visibility of the window is large, which hinders the improvement of the fuel consumption characteristics of the vehicle. In particular, in winter, when the temperature difference between indoors and outdoors becomes severe, especially in cold regions where the environment can be below freezing, the energy consumed to secure the visibility of the windows becomes even greater.

In addition, there is a problem such as increased discomfort in the vehicle interior due to the dry state, and providing a window glass that can reduce these problems, that is, providing an antifogging article, is for an environment-friendly vehicle. Is essential. Furthermore, in electric vehicles such as hybrid vehicles and fuel cell vehicles, the need for anti-fogging coatings is expected to increase more and more.

As a vehicle antifogging glass, Patent Document 1 discloses an antifogging vehicle glass obtained by applying a composition containing an organic antifogging material to an ultraviolet ray low-transmitting glass. Further, Patent Document 2 discloses a vehicle window glass in which a hydrophilic layer containing alumina is provided on an indoor surface and a contact angle with water is 30 ° or less.

Patent Document 3 proposes an antifogging coating suitable for a vehicle window that makes it easy to secure the field of view of a window even in a cold region where a freezing environment can occur. In the antifogging glass, a film made of an antifogging urethane resin having hydrophilicity and water absorption is used. The antifogging property is designed such that the antifogging property is first manifested by the water absorption of the coating, and the antifogging property is continued by the hydrophilicity of the coating after the water absorption is saturated. Moreover, the abrasion resistance is also excellent due to the elasticity inherent in the urethane resin. Furthermore, a film having metal oxide fine particles or a silane coupling agent is disclosed as a suitable form for increasing the hardness of the film.

Patent Document 4 discloses a hydrophilic polyurethane having a hydrolyzable silyl group, that is, an antifogging urethane resin, and crosslinks the hydrolyzable silyl group with another hydrolyzable silyl group using moisture. Thus, a film with improved surface strength is provided.
JP 2000-239045 A JP2003-321251A JP 2005-029723 A JP 2000-63470 A

The present invention uses an antifogging urethane resin, further improves the hardness and wear resistance, an antifogging coating, a coating solution for forming an antifogging coating for forming the antifogging coating, and the An object of the present invention is to provide a method for forming an antifogging film using a coating solution for forming an antifogging film.

The coating solution for forming an antifogging film of the present invention is:
A coating solution for forming an antifogging film prepared from three kinds of raw materials for preparation,
The above three preparation raw materials are
A raw material (I) containing a reaction product (A) of an isocyanate component having an isocyanate group and a water-absorbing polyol having a number average molecular weight of 400 to 5000,
A raw material (II) containing a hydrolyzed polycondensate (B) of a plurality of silicon oxide precursors (b), and
Consists of raw material (III) containing metal oxide ultrafine particles (C),
The ratio of the reaction product (A) to the total amount of the reaction product (A), the hydrolysis polycondensation product (B) and the metal oxide ultrafine particles (C) is 25 to 40% by weight, and the hydrolysis polycondensation product ( The proportion of B) is 21 to 50% by weight, the proportion of the metal oxide ultrafine particles (C) is 25 to 45% by weight,
The ratio of the tetraalkoxysilane (b1) to the total amount of the plurality of silicon oxide precursors (b) is 14 to 27% by weight, the ratio of the alkyl group-containing trialkoxysilane (b2) is 14 to 27% by weight, epoxy The ratio of trialkoxysilane (b3) containing at least one of a group, a mercapto group and an amino group is 46 to 72% by weight.

The antifogging film of the present invention is
An antifogging film formed on a substrate using the antifogging film forming coating solution,
In the antifogging film, the reaction product (A) and the hydrolysis polycondensation product (B) form a chemical bond, and the chemical bond remains in the reaction product (A). It is characterized in that it is formed from an isocyanate group and at least one of an epoxy group, a mercapto group and an amino group present in the hydrolysis polycondensate (B).

In addition, the method of forming the antifogging film of the present invention includes:
A method for forming the antifogging film,
Antifogging by mixing raw material (I) containing reaction product (A), raw material (II) containing hydrolysis polycondensate (B), and raw material (III) containing ultrafine metal oxide (C) A step of obtaining a coating liquid for forming a conductive film,
Applying the coating solution for forming the anti-fogging film on a substrate; and
It includes a step of heating the coating layer coated on the substrate.

The antifogging film formed from the coating solution for forming an antifogging film of the present invention is excellent in antifogging and dust resistance due to water absorption of the film and has high film hardness, and can withstand long-term use. Further, since it is possible to develop antifogging properties without depending on the formation of a water film, it is particularly suitably used for automobile windows.

Hereinafter, the coating solution for forming an antifogging film of the present invention is a coating solution for forming an antifogging film prepared from three kinds of raw materials for preparation, and the three kinds of raw materials for preparation are reaction products (A) 25 to 25. Raw material (I) containing 40 wt%, raw material (II) containing 21 to 50 wt% of hydrolyzed polycondensate (B), and raw material (III) containing 25 to 45 wt% of metal oxide ultrafine particles (C) ).
The reaction product (A), hydrolysis polycondensation product (B), and metal oxide ultrafine particles (C) are used for three kinds of preparations so that the respective weight ratios are 100% by weight. A raw material is added to prepare a coating solution for forming an antifogging film. Moreover, the said ratio means the solid content weight ratio of a reaction product (A), a hydrolysis polycondensate (B), and a metal oxide ultrafine particle (C).

First, the action and effect of the antifogging coating of the present invention will be described in detail.
The reaction product (A) is a reaction product (A) of an isocyanate component having an isocyanate group and a water-absorbing polyol having a number average molecular weight of 400 to 5000, and has a urethane bond and an unreacted isocyanate group. , It plays a role of providing water absorption, that is, antifogging property, to the formed antifogging film.

The hydrolyzed polycondensate (B) is a hydrolyzed polycondensate (B) of a plurality of silicon oxide precursors (b), and contains at least one of an epoxy group, a mercapto group, and an amino group. Can react with an unreacted isocyanate group in the reaction product (A), and thus can be combined with the reaction product (A).

Thus, the film formed from the coating solution for forming an antifogging film of the present invention (hereinafter also referred to as coating solution) is a chemical product of the reaction product (A) and the hydrolyzed polycondensate (B). It has a bond and a cross-linked structure formed by the reaction product (A) and the hydrolyzed polycondensate (B), and the hydrolyzed polycondensate (B) plays a role in improving the hardness of the film. Plays. That is, as the proportion of the hydrolyzed polycondensate (B) increases, the wear resistance of the coating tends to improve.
The epoxy group is opened by hydrolysis to form a hydroxyl group (—OH group), and the ring-opened group reacts with the isocyanate group.

The metal oxide ultrafine particles (C) also play a role of improving the hardness of the coating, and the wear resistance of the coating tends to improve as the proportion of the metal oxide ultrafine particles (C) increases.

When trying to apply a water-absorbing resin to an antifogging film, a contradictory relationship is likely to occur, and it has been difficult to improve both the antifogging property and the film hardness. The reason for this is that the antifogging coating of the type as in the present invention exhibits antifogging properties due to the water absorption of a polymer having a polyurethane bond, and is intended to improve the hardness of the antifogging coating. This is because, when the content is increased, components that cause water absorption relatively decrease.

The reaction product (A) constituting the anti-fogging film undergoes a structural change from a linear structure to a meander type structure in which the oxyalkylene chain constituting the water-absorbing polyol is bent when the film absorbs water. If it is possible to introduce a hydrolysis condensate that does not inhibit this structural change in introducing an inorganic component that is considered to be generated and chemically bonded to the reaction product (A), the antifogging property and hardness of the coating can be improved. It is thought that both can be achieved.

When forming the antifogging film of the present invention, the above-mentioned reaction product (A), hydrolysis polycondensation product (B) and metal oxide ultrafine particles (C) are used in the above-mentioned ratio, and water is added. Various alkoxysilanes forming the decomposition condensate (B) include tetraalkoxysilane (bl), trialkoxysilane containing alkyl group (b2), trialkoxysilane (b3) containing at least one of an epoxy group, a mercapto group and an amino group. It is considered that the use of this prevents the change of the structure from the linear structure of the oxyalkylene chain to the twisted structure from being hindered, and can achieve both the antifogging property and the hardness of the film.

That is, the component forming the hydrolysis condensate (B) is tetraalkoxysilane (b1) that forms a dense siloxane network, alkyl group-containing trialkoxysilane that forms a siloxane network that is somewhat sparse and has spatial gaps (B2) The amount of trialkoxysilane (b3) (hereinafter also referred to as trialkoxysilane (b3)) containing at least one of an epoxy group, mercapto group and amino group (hereinafter also referred to as trialkoxysilane (b2)) It is thought that the structural change at the time of water absorption of the reaction product (A) is no longer inhibited by the selective preparation.

Moreover, when obtaining the antifogging film solidified after apply | coating a coating liquid on a board | substrate, shrinkage | contraction may arise in the part of a hydrolysis-condensation product (B). Therefore, stress may be generated in the hydrolysis-condensation product (B) during the film formation process, but the stress generated by the component derived from trialkoxysilane (b2) and trialkoxysilane (b3) is relieved. From the coating solution of the invention, for example, even if a thick antifogging film such as 100 μm is formed, it is considered that a large stress hardly acts upon shrinkage and an antifogging film having excellent characteristics can be formed.

Next, three kinds of preparation raw materials will be described.
First, a method for preparing the reaction product (A) and the raw material (I) containing the reaction product (A) will be described.
The reaction product (A) is a reaction product of an isocyanate component having an isocyanate group and a water-absorbing polyol having a number average molecular weight of 400 to 5000.

The ratio of the reaction product (A) to the total amount of the reaction product (A), the hydrolysis polycondensation product (B) and the metal oxide ultrafine particles (C) is 25 to 40% by weight, but 28 to 38%. % By weight is preferable, and 30 to 34% by weight is more preferable.
When the proportion of the reaction product (A) is less than 25% by weight, the antifogging property of the formed antifogging film tends to be insufficient, while the proportion of the reaction product (A) exceeds 40% by weight. And the hardness of the anti-fogging film formed tends to be insufficient.

Examples of the isocyanate component include organic polyisocyanates such as organic diisocyanate, biuret using hexamethylene diisocyanate as a starting material, and trifunctional polyisocyanate having an isocyanurate structure. These compounds have weather resistance, chemical resistance, and heat resistance, and are particularly excellent in weather resistance. Moreover, as an isocyanate component other than the said compound, diisophorone diisocyanate, diphenylmethane diisocyanate, bis (methylcyclohexyl) diisocyanate, toluene diisocyanate etc. are mentioned, for example.

Examples of the water-absorbing polyol include a polyol having an oxyethylene chain. Among the above polyols, those having an oxyethylene chain and an oxypropylene chain are preferable, and in particular, the ability to absorb water as bound water. Particularly excellent polyethylene glycol is preferred.

The number average molecular weight of the water-absorbing polyol of the present invention is 400 to 5000. When the number average molecular weight is less than 400, the ability to absorb water as bound water is low, and when the number average molecular weight exceeds 5000, the strength of the coating tends to be lowered. In consideration of water absorption and film hardness, the number average molecular weight is preferably 400 to 2,000.

Moreover, you may form reaction product (A) using polyols, such as polyester polyol, as a hydrophobic polyol to such an extent that the water absorption of reaction product (A) is not inhibited.
Furthermore, the coating film may be used for applications such as a window glass for a building, a mirror, a spectacle lens, and goggles for utilizing the hydrophilicity of the coating to exhibit antifogging properties. In the case of these applications, hydrophilicity may be imparted to the reaction product (A). And for this purpose, a surfactant can be introduced into the reactive product (A).

In order to prevent the surfactant from eluting from the anti-fogging film, it is preferable that the surfactant is bonded to the resin bridge. In order to make it the state couple | bonded with resin bridge | crosslinking, it is preferable to set it as the reactive group containing surfactant. When the reactive group is a hydroxyl group, an amino group, a mercapto group, or the like, the reactive group reacts with an isocyanate group, and the surfactant can be chemically bonded to the resin crosslink. Alternatively, an isocyanate group may be provided on the surfactant and reacted with a water-absorbing polyol.

When preparing the raw material (I) containing the reaction product (A), a predetermined amount of an isocyanate component having an isocyanate group, a water-absorbing polyol having a number average molecular weight of 400 to 5000, an organic solvent, and a curing catalyst is blended. Mix well by stirring well. Thereby, coating liquid (I) (raw material (I)) is prepared.

The time for stirring is preferably 10 minutes to 20 days, and particularly preferably 2 hours to 5 hours, but is not limited to this when stirring is performed at a temperature other than room temperature. Further, by heating, the reaction can be promoted and the stirring time can be shortened. The liquid temperature during stirring is preferably 15 to 80 ° C.

The number of isocyanate groups present in the isocyanate component is preferably 0.5 to 3 times, more preferably 0.8 to 1.2 times the number of hydroxyl groups present in the water-absorbing polyol component. More preferred. When the amount of the isocyanate component is less than 0.5 times, the curability of the coating solution is deteriorated, the formed film is soft, and the water-absorbing polyol is eluted when the film is left for a long period of time. On the other hand, when the amount exceeds 3 times, the antifogging property is deteriorated because the water absorption and dehydration is inhibited by excessive curing.

The organic solvent needs to be a solvent that is not active with respect to the isocyanate group. From the viewpoint of compatibility with the reaction product (A), for example, ester solvents such as ethyl acetate, butyl acetate, and isobutyl acetate, acetone , Ketones such as methyl ethyl ketone and methyl isobutyl ketone, and diacetone alcohol are preferable.
As for the compounding quantity of an organic solvent, 100-400 weight part is preferable with respect to 100 weight part of reaction products (A).

A curing catalyst is added to increase the curing rate of the coating, and examples of the curing catalyst include organic tin compounds. Examples of the compound include dibutyltin dilaurate, dioctyltin dilaurate, stannous octoate, dibutyltin dioctoate, dibutyltin diacetate, dibutyltin marker butylide, dibutyltin thiocarboxylate, dibutyltin dimaleate, dioctyltin marker butylide, dioctyltin thiol Examples include carboxylate.
As for the compounding quantity of a curing catalyst, 0.01-0.2 weight part is preferable with respect to 100 weight part of reaction products (A).

Thus, the reaction product (A) is included by mixing the isocyanate component having an isocyanate group, a water-absorbing polyol having a number average molecular weight of 400 to 5000, an organic solvent, and a curing catalyst in a predetermined amount and stirring well. Coating liquid (I) (raw material (I)) can be obtained.

In the raw material (I) containing the reaction product (A), a urethane bond is formed by the reaction between the isocyanate component and the water-absorbing polyol, resulting in a polymer, but some unreacted isocyanate groups exist. In the case where the amount of isocyanate groups is small, hydroxyl groups are also present.

Next, the hydrolysis polycondensate (B) of a plurality of silicon oxide precursors (b) and a method for preparing the raw material (II) containing the hydrolysis polycondensate (B) will be described.

The hydrolyzed polycondensate (B) is a hydrolyzed polycondensate of a plurality of silicon oxide precursors (b). The reaction product (A), hydrolyzed polycondensate (B), and metal oxide ultrafine particles ( The ratio of the hydrolysis polycondensate (B) to the total amount of C) is 25 to 50% by weight, preferably 25 to 45% by weight, and more preferably 32 to 36% by weight.
When the ratio of the hydrolyzed polycondensate (B) is less than 25% by weight, the hardness of the antifogging film formed tends to be insufficient, while the ratio of the hydrolyzed polycondensate (B) is 50% by weight. If it exceeds 1, the hardness of the antifogging film formed is sufficient, but the antifogging property tends to be lowered.

Moreover, although the ratio of the tetraalkoxysilane (b1) with respect to the total amount of a silicon oxide precursor (b) is 14 to 27 weight%, 17 to 25 weight% is preferable and 19 to 23 weight% is more preferable.
When the proportion of tetraalkoxysilane (b1) is less than 14% by weight, the hardness of the antifogging film formed tends to be insufficient, while when the proportion of tetraalkoxysilane (b1) exceeds 27% by weight, Since the formed antifogging film becomes too dense, the antifogging property tends to be lowered.

Examples of the tetraalkoxysilane (b1) include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetraisopropoxysilane.

The ratio of trialkoxysilane (b2) to the total amount of silicon oxide precursor (b) is 14 to 27% by weight, preferably 17 to 25% by weight, and more preferably 19 to 23% by weight.
When the ratio of trialkoxysilane (b2) is less than 14% by weight, the flexibility is hardly sufficient and the antifogging property of the formed antifogging film tends to be lowered, whereas the trialkoxysilane (b2) If the ratio exceeds 27% by weight, the antifogging property of the formed antifogging film is ensured, but the hardness tends to be insufficient.

Examples of trialkoxysilane (b2) include methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltriisopropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltripropoxysilane, and ethyltriisosilane. Examples include propoxysilane, propyltrimethoxysilane, propyltriethoxysilane, propyltripropoxysilane, and propyltriisopropoxysilane.

The ratio of trialkoxysilane (b3) to the total amount of silicon oxide precursor (b) is 46 to 72% by weight, preferably 50 to 67% by weight, and more preferably 56 to 60% by weight.
When the proportion of trialkoxysilane (b3) is less than 46% by weight, the antifogging property of the formed antifogging film tends to decrease, while the proportion of trialkoxysilane (b3) exceeds 72% by weight. However, the antifogging property of the formed antifogging film is ensured, but the hardness tends to be insufficient.

Examples of trialkoxysilane (b3) include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 5,6-epoxyhexyltriethoxysilane, and 5,6-epoxyhexyltriethoxysilane. 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 3-oxetanylpropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-amino Examples include propyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-mercaptopropyltriethoxysilane.

As a combination of the silicon oxide precursor (b), (b1), tetraethoxysilane (TEOS), trimethoxysilane (b2), methyltriethoxysilane (MTES), trimethoxysilane (b3), 3- Glycidoxypropyltrimethoxysilane (GPTMS) is desirable, and by using such a silicon oxide precursor (b), it is possible to form an antifogging film that is excellent in wear resistance and can be fired at a low temperature.

When preparing the raw material (II) containing the hydrolysis polycondensate (B), tetraalkoxysilane (b1), trialkoxysilane (b2), trialkoxysilane (b3), an organic solvent, and an acid catalyst are added. Mix in a predetermined amount and mix well. Thereby, coating liquid (II) (raw material (II)) is prepared.

The stirring time is preferably 10 minutes to 20 days, and particularly preferably 1 hour to 4 days, but is not limited to this when stirring is performed at a temperature other than room temperature. Further, by heating, the reaction can be promoted and the stirring time can be shortened. The liquid temperature during stirring is preferably 15 to 80 ° C.

As an organic solvent, it is necessary to make the solvent inactive with respect to the isocyanate group so as not to cause inconvenience when mixed with the reaction product (A), and the phase with the hydrolyzed polycondensate (B). From the viewpoint of solubility, for example, ester solvents such as ethyl acetate, butyl acetate and isobutyl acetate, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, and diacetone alcohol are preferred.
As for the compounding quantity of an organic solvent, 100-900 weight part is preferable with respect to 100 weight part of hydrolysis polycondensates (B).

As the acid catalyst, inorganic acids such as hydrochloric acid, sulfuric acid and nitric acid, organic acids such as acetic acid, phthalic acid and succinic acid are selected. And it is preferable that they are prepared and added to 0.0001N-10N aqueous solution.
As for the compounding quantity of a curing catalyst, 1-10 weight part is preferable with respect to 100 weight part of hydrolysis polycondensates (B).

In this way, a predetermined amount of tetraalkoxysilane (b1), trialkoxysilane (b2), trialkoxysilane (b3), organic solvent, and acid catalyst are blended, and the mixture is stirred and mixed to hydrolyze polycondensation. The coating liquid (II) (raw material (II)) containing the product (B) can be obtained.

Next, the raw material (III) containing the metal oxide ultrafine particles (C) will be described.
The ratio of the metal oxide ultrafine particles (C) to the total amount of the reaction product (A), the hydrolysis polycondensate (B) and the metal oxide ultrafine particles (C) is 25 to 45% by weight. -40 wt% is preferable, and 32-36 wt% is more preferable.
When the ratio of the metal oxide ultrafine particles (C) is less than 25% by weight, the hardness of the formed antifogging film tends to be insufficient, whereas the ratio of the metal oxide ultrafine particles (C) is 40% by weight. If it exceeds 1, the hardness of the antifogging film formed is sufficient, but the antifogging property tends to be lowered.

Examples of the metal oxide ultrafine particles (C) include silica, titania, zirconia, alumina, niobium oxide, and tantalum oxide.

The metal oxide ultrafine particles (C) having an average particle size of 200 nm or less, preferably 100 nm or less are preferably used. In general, it is said that the scattering is maximized in a particle having a particle size of about half the wavelength of a certain light. For this reason, the average particle diameter of the metal oxide ultrafine particles is preferably 200 nm or less, more preferably 100 nm or less, which is half of the shortest wavelength of visible light, 400 nm. The average particle diameter is measured by a method according to “JIS H7804”.

The metal oxide ultrafine particles (C) are desirably provided in a state of being dispersed in a dispersion medium. Usually, the metal oxide ultrafine particles (C) are dispersed as the coating liquid (III) (raw material (III)). Although the thing of the state disperse | distributed in the medium is used, the powder of a metal oxide ultrafine particle (C) can also be used as it is. As the dispersion medium, it is preferable to use a dispersion medium that is not active with respect to an isocyanate group. In particular, in view of compatibility with a coating solution, for example, an ester system such as ethyl acetate, butyl acetate, or isobutyl acetate. A dispersion medium mainly composed of a solvent, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, and diacetone alcohol is preferred.
The blending amount of the organic solvent is preferably 100 to 900 parts by weight with respect to 100 parts by weight of the metal oxide ultrafine particles (C).

The method for forming the antifogging film of the present invention will be described.
The method for forming the antifogging film of the present invention is as follows:
Coating solution (I) containing reaction product (A) (raw material (I)), coating solution (II) containing hydrolysis polycondensate (B) (raw material (II)), and metal oxide ultrafine particles ( A step of mixing a coating liquid (III) containing C) (raw material (III)) to obtain a coating liquid for forming an antifogging film;
Applying the coating solution for forming the anti-fogging film on a substrate; and
It includes a step of heating the coating layer coated on the substrate.

First, a process for obtaining a coating solution for forming an antifogging coating, that is, a method for preparing a coating solution for forming an antifogging coating will be described.
As described above, the coating solution comprises the coating solution (I) containing the reaction product (A), the coating solution (II) containing the hydrolysis polycondensate (B), and the metal oxide ultrafine particles (C). It is obtained by mixing a predetermined amount of the coating liquid (III) containing the mixture and stirring them well.

The stirring time is preferably 10 minutes to 20 days, and particularly preferably 30 minutes to 2 hours, but is not limited to this when stirring is performed at a temperature other than room temperature. Further, by heating, the reaction can be promoted and the stirring time can be shortened. The liquid temperature during stirring is preferably 15 to 80 ° C.
The stirring method is not particularly limited, and examples thereof include stirring using a stirring blade and stirring using a mixer such as a static mixer.

Next, the process of apply | coating the coating liquid for antifogging film formation on a base material is demonstrated.
As a means for applying the coating liquid to the transparent substrate, known means such as spin coating, dip coating, flow coating, roll coating, spray coating, screen printing, flexographic printing, etc. can be employed.

Examples of the substrate include plate glass. The plate glass is a plate glass usually used for automobiles, buildings, industrial glasses, etc., and the production method is not particularly limited, and is obtained by any method such as a float method, a duplex method, a roll-out method. There may be.

Examples of glass types include various colored glasses such as clear, green and bronze, various functional glasses such as UV, IR cut glass, and electromagnetic shielding glass, netted glass, low expansion glass, fire expansion glass such as zero expansion glass, and the like. Examples of usable glass products include glass, tempered glass and similar glass, laminated glass, multilayer glass, and various glass products such as flat plates and bent plates.

Although plate | board thickness is not specifically limited, For example, 1.0 mm or more and 10 mm or less are preferable, and for vehicles, 1.0 mm or more and 5.0 mm or less are preferable. The antifogging film is preferably formed on the substrate only on one side, but may be performed on both sides depending on the application. Further, the film may be formed on the entire surface or a part of the substrate surface.

When a coating solution is applied to a glass substrate to form a coating, a solution having a silane coupling agent may be applied before the coating solution is applied in order to improve the adhesion between the substrate and the coating. preferable. As suitable silane coupling agents, 3-glycidoxypropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, and the like can be used.

As the transparent substrate, in addition to the above plate glass, for example, a resin film such as polyethylene terephthalate, a resin plate such as polycarbonate, and the like can be used.

Next, the process of heating the coating layer coated on the substrate will be described.
As heating conditions, heating at 50 to 200 ° C. for 5 minutes to 1 hour is preferable. The heating method is not particularly limited, and for example, hot air may be blown using a blower or the like, but is usually performed by carrying it in a heating furnace.
In the heating step, the crosslinking further proceeds and the condensation also proceeds, and the antifogging film of the present invention having the above-described characteristics is formed.

The anti-fogging film of the present invention is water-absorbing and exhibits anti-fogging properties. Therefore, a correlation tends to occur between the film thickness and the anti-fogging property of the anti-fogging coating, and good anti-fogging properties are obtained. The antifogging film preferably has a certain film thickness, for example, 3 μm to 100 μm. The thickness of the antifogging coating is more preferably 4 to 70 μm, and further preferably 5 to 60 μm.

The anti-fogging coating of the present invention has the structure as described at the beginning. Therefore, it has excellent wear resistance, high film hardness, and can withstand long-term use.

The present invention will be specifically described below with reference to examples. In addition, quality evaluation was performed by the method shown below with respect to the antifogging composition obtained by the present Example and the comparative example.

[Appearance evaluation]: The appearance, permeability, and presence / absence of cracks of the anti-fogging coating film were visually evaluated, and those having no problem were evaluated as acceptable (◯) and those having problems as unacceptable (×).
[Anti-fogging property]: Hold the sample for 12 hours in an environment of 25 ° C. and 60% RH, blow on the surface of the sample, and pass (○) if it does not cloud when blown. The case where it occurred was regarded as rejected (x).

[Taber wear resistance]: Measures the fogging change when CF-10F is used as a wear wheel and the load is 4.9 N 100 times, and passes the haze change ΔH ≦ 4%. Those with ΔH> 4% were regarded as rejected (x).

[Traverse wear resistance]: Appearance and anti-fogging anti-fogging properties were measured when nel (cotton No. 300) was reciprocated 5000 times with a load of 4.9 N / 4 cm ² on the membrane surface. Those with abnormalities were determined to be rejected (x).

[Pencil Hardness]: The hardness of the hardest pencil with no scars was defined as the pencil hardness according to the “JIS K5600” paint general test method. The pencil hardness can be used as an index of scratch resistance.

Example 1
(Preparation of coating solution (I) having reaction product (A))
As the isocyanate having an isocyanate group, hexamethylene diisocyanate burette type polyisocyanate (trade name “N3200”, manufactured by Sumitomo Bayer Urethane) and polyethylene glycol having an average molecular weight of 1000 were used. Add and mix 27 g of polyethylene glycol and 8 g of N3200 so that the number of isocyanate groups present in the isocyanate component is 0.9 times the number of hydroxyl groups present in polyethylene glycol. Methyl ethyl ketone was added and mixed as a solvent so that the total amount was 35% by weight to prepare a coating solution (I).

(Preparation of coating liquid (II) having hydrolyzed polycondensate (B))
Tetraalkoxysilane (TES) as tetraalkoxysilane (b1), methyltriethoxysilane (MTES) as alkyl group-containing trialkoxysilane (b2), trialkoxysilane (b3) containing epoxy group, mercapto group or amino group as 3 -Glycidoxypropyltrimethoxysilane (GPTMS) was used. TEOS: 12 g, MTES: 9 g, GPTMS: 16 g, 0.5N acetic acid: 27 g are added and mixed, and methyl ethyl ketone is added and mixed as a solvent so that the solid content concentration is 17.5% by weight. Prepared.

(Preparation of coating solution)
The coating liquid (I), the coating liquid (II), and colloidal silica (trade name “MEK-ST”, solid content 20%, manufactured by Nissan Chemical Co., Ltd.) using methyl ethyl ketone as a solvent as the metal oxide ultrafine particles (C). When the coating liquid (III) was mixed, the weight ratio of the solid content of the reaction product (A), the hydrolysis polycondensation product (B), and the metal oxide ultrafine particles (C) was 32:34:34, A mixture of tetraalkoxysilane (b1), trialkoxysilane (b2) and trialkoxysilane (b3) in the decomposed polycondensate (B) is mixed so that the weight ratio by weight is 21:21:58, and methyl ethyl ketone is used as a solvent. Were added and mixed to prepare a coating solution.

(Application of coating solution to substrate)
A solution of 3-aminopropyltriethoxysilane (LS-3150, manufactured by Shin-Etsu Silicone Co., Ltd.) was prepared to 1 wt% with methyl ethyl ketone. Next, 100 mm × 100 mm (3.5 mm thickness) of a wiper made of cellulose fibers that absorbed the solution (trade name “Bencot”, model M-1, 50 mm × 50 mm, manufactured by Ozu Sangyo) was obtained by the float method. The solution was applied by wiping the glass substrate surface, dried at room temperature, and then washed with a wiper with tap water to prepare a transparent substrate.

The coating solution obtained above was applied to the transparent substrate by spin coating, and the glass plate to be coated was heat-treated at about 150 ° C. for about 30 minutes to obtain an antifogging film having a thickness of 10 μm.
About the anti-fogging film obtained by the said method, it evaluated using the above-mentioned evaluation method. The results are shown in Table 1.
As shown in Table 1, it was confirmed that the article had no problem in appearance, was excellent in antifogging property and scratch resistance, and had an excellent pencil hardness of 3H and film hardness.

Example 2
Antifogging in the same procedure as in Example 1 except that the solid content weight ratio of the reaction product (A), hydrolysis polycondensate (B), and metal oxide ultrafine particles (C) was 25:34:41. The product was obtained and evaluated by the above method. The results are shown in Table 1.
As shown in Table 1, the obtained article was confirmed to be an article having no problem in appearance, good antifogging property, excellent scratch resistance, and excellent pencil hardness of 4H and film hardness. .

Example 3
Antifogging was carried out in the same procedure as in Example 1 except that the solid content weight ratio of the reaction product (A), hydrolysis polycondensation product (B), and metal oxide ultrafine particles (C) was 40:34:26. The product was obtained and evaluated by the above method. The results are shown in Table 1.
As shown in Table 1, the obtained article was confirmed to be an article having no problem in appearance, good antifogging properties, excellent scratch resistance, and excellent pencil hardness of 3H and film hardness. .

Example 4
Example 1 except that the solid content weight ratio of tetraalkoxysilane (b1), trialkoxysilane (b2), trialkoxysilane (b3) in the hydrolysis polycondensate (B) was 14:25:61. An antifogging article was obtained in the same procedure and evaluated by the above method. The results are shown in Table 1.
As shown in Table 1, it was confirmed that the obtained article had no problem in appearance, was excellent in antifogging property and scratch resistance, and had a good pencil hardness of 3H and film hardness.

Example 5
Example 1 except that the solid content weight ratio of tetraalkoxysilane (b1), trialkoxysilane (b2), trialkoxysilane (b3) in the hydrolyzed polycondensate (B) was 27:18:55. An antifogging article was obtained in the same procedure and evaluated by the above method. The results are shown in Table 1.
As shown in Table 1, the obtained article was confirmed to be an article having no problem in appearance, good antifogging property, excellent scratch resistance, and excellent pencil hardness of 4H and film hardness. .

Example 6
Example 1 except that the solid content weight ratio of tetraalkoxysilane (b1), trialkoxysilane (b2), trialkoxysilane (b3) in the hydrolysis polycondensate (B) was 25:14:61. An antifogging article was obtained in the same procedure and evaluated by the above method. The results are shown in Table 1.
As shown in Table 1, the obtained article was confirmed to be an article having no problem in appearance, good antifogging property, excellent scratch resistance, and good pencil hardness of 3H and film hardness. .

Example 7
Example 1 except that the solid content weight ratio of tetraalkoxysilane (b1), trialkoxysilane (b2), trialkoxysilane (b3) in the hydrolysis polycondensate (B) was 18:27:55. An antifogging article was obtained in the same procedure and evaluated by the above method. The results are shown in Table 1.
As shown in Table 1, the obtained article was confirmed to be an article having no problem in appearance, good antifogging property, excellent scratch resistance, and good pencil hardness of 3H and film hardness. .

Example 8
Example 1 except that the solid content weight ratio of tetraalkoxysilane (b1), trialkoxysilane (b2), trialkoxysilane (b3) in the hydrolysis polycondensate (B) was 27:27:46. An antifogging article was obtained in the same procedure and evaluated by the above method. The results are shown in Table 1.
As shown in Table 1, the obtained article was confirmed to be an article having no problem in appearance, good antifogging property, excellent scratch resistance, and good pencil hardness of 3H and film hardness. .

Example 9
Example 1 except that the solid content weight ratio of tetraalkoxysilane (b1), trialkoxysilane (b2), trialkoxysilane (b3) in the hydrolysis polycondensate (B) was 14:14:72. An antifogging article was obtained in the same procedure and evaluated by the above method. The results are shown in Table 1.
As shown in Table 1, the obtained article was confirmed to be an article having no problem in appearance, good antifogging property, excellent scratch resistance, and good pencil hardness of 3H and film hardness. .

Example 10
Antifogging was carried out in the same procedure as in Example 1 except that the solid content weight ratio of the reaction product (A), hydrolysis polycondensation product (B), and metal oxide ultrafine particles (C) was 34:21:45. The product was obtained and evaluated by the above method. The results are shown in Table 1.
As shown in Table 1, the obtained article was confirmed to be an article having no problem in appearance, good antifogging property, excellent scratch resistance, and excellent pencil hardness of 4H and film hardness. .

Example 11
Antifogging in the same procedure as in Example 1 except that the solid content weight ratio of the reaction product (A), hydrolyzed polycondensate (B), and metal oxide ultrafine particles (C) was 25:50:25. The product was obtained and evaluated by the above method. The results are shown in Table 1.
As shown in Table 1, the obtained article was confirmed to be an article having no problem in appearance, good antifogging property, excellent scratch resistance, and good pencil hardness of 3H and film hardness. .

Example 12
In the preparation of the coating liquid (A) having the reaction product (A), an antifogging article was obtained in the same procedure as in Example 1 except that polyethylene glycol having an average molecular weight of 2000 was used, and evaluated by the above method. It was. The results are shown in Table 1.
As shown in Table 1, it was confirmed that the obtained article had no problem in appearance, was excellent in antifogging property and scratch resistance, and had a good pencil hardness of 3H and film hardness.

Comparative Example 1
Antifogging was carried out in the same procedure as in Example 1 except that the solid content weight ratio of the reaction product (A), hydrolysis polycondensation product (B), and metal oxide ultrafine particles (C) was 20:34:46. The product was obtained and evaluated by the above method. The results are shown in Table 2.
As shown in Table 2, the obtained article was an article showing no antifogging property.

Comparative Example 2
Antifogging in the same procedure as in Example 1 except that the solid content weight ratio of the reaction product (A), hydrolysis polycondensation product (B), and metal oxide ultrafine particles (C) was 45:34:21. The product was obtained and evaluated by the above method. The results are shown in Table 2.
As shown in Table 2, the obtained article is cloudy and has a problem in appearance. In the traverse test, the film is scratched after 1000 reciprocations, and the pencil hardness is H and the film hardness is insufficient. there were.

Comparative Example 3
Example 1 except that the solid content weight ratio of tetraalkoxysilane (b1), trialkoxysilane (b2), trialkoxysilane (b3) in the hydrolysis polycondensate (B) was 10:26:64. An antifogging article was obtained in the same procedure and evaluated by the above method. The results are shown in Table 2.
As shown in Table 2, the obtained article was scratched on the film after 3000 reciprocations in the traverse test, and the pencil hardness was insufficient for HB and film hardness.

Comparative Example 4
Example 1 except that the solid content weight ratio of tetraalkoxysilane (b1), trialkoxysilane (b2), trialkoxysilane (b3) in the hydrolyzed polycondensate (B) was 30:16:54. An antifogging article was obtained in the same procedure and evaluated by the above method. The results are shown in Table 2.
As shown in Table 2, the obtained article was an article showing no antifogging property.

Comparative Example 5
Example 1 except that the solid content weight ratio of tetraalkoxysilane (b1), trialkoxysilane (b2), trialkoxysilane (b3) in the hydrolyzed polycondensate (B) was 31: 0: 69. An antifogging article was obtained in the same procedure and evaluated by the above method. The results are shown in Table 2.
As shown in Table 2, the obtained article was an article showing no antifogging property.

Comparative Example 6
Example 1 except that the solid weight ratio of tetraalkoxysilane (b1), trialkoxysilane (b2), trialkoxysilane (b3) in the hydrolysis polycondensate (B) was 26:10:64. An antifogging article was obtained in the same procedure and evaluated by the above method. The results are shown in Table 2.
As shown in Table 2, the obtained article was an article that did not exhibit antifogging properties.

Comparative Example 7
Example 1 except that the solid content weight ratio of tetraalkoxysilane (b1), trialkoxysilane (b2), trialkoxysilane (b3) in the hydrolysis polycondensate (B) was 16:30:54. An antifogging article was obtained in the same procedure and evaluated by the above method. The results are shown in Table 2.
As shown in Table 2, the obtained article was scratched on the film after 3000 reciprocations in the traverse test, and the pencil hardness was insufficient for HB and film hardness.

Comparative Example 8
Example 1 except that the solid weight ratio of tetraalkoxysilane (b1), trialkoxysilane (b2), trialkoxysilane (b3) in the hydrolysis polycondensate (B) was 50: 50: 0. An antifogging article was obtained in the same procedure and evaluated by the above method. The results are shown in Table 2.
As shown in Table 2, the obtained article did not show any antifogging property and was an article in which the film peeled after the test in the Taber test.

Comparative Example 9
Example 1 except that the solid content weight ratio of the tetraalkoxysilane (b1), trialkoxysilane (b2), and trialkoxysilane (b3) in the hydrolyzed polycondensate (B) was 30:30:40. An antifogging article was obtained in the same procedure and evaluated by the above method. The results are shown in Table 2.
As shown in Table 2, the obtained article was an article having a high fogging change ΔH = 18.5% after the test in the Taber test.

Comparative Example 10
Example 1 except that the solid weight ratio of tetraalkoxysilane (b1), trialkoxysilane (b2), trialkoxysilane (b3) in the hydrolysis polycondensate (B) was 10:10:80. An antifogging article was obtained in the same procedure and evaluated by the above method. The results are shown in Table 2.
As shown in Table 2, the obtained article did not exhibit any antifogging property, and the film was damaged after 3000 reciprocations in the traverse test, and the pencil hardness was insufficient for HB and film hardness.

Comparative Example 11
Antifogging in the same procedure as in Example 1 except that the solid content weight ratio of the reaction product (A), hydrolysis polycondensation product (B), and metal oxide ultrafine particles (C) was 32:10:58. The product was obtained and evaluated by the above method. The results are shown in Table 2.
As shown in Table 2, the obtained article did not show any antifogging property and was an article in which the film peeled after the test in the Taber test.

Comparative Example 12
Antifogging in the same procedure as in Example 1 except that the solid content weight ratio of the reaction product (A), hydrolyzed polycondensate (B), and metal oxide ultrafine particles (C) was 32: 60: 8. The product was obtained and evaluated by the above method. The results are shown in Table 2.
As shown in Table 2, the obtained article had scratches on the film after 2000 reciprocations in the traverse test, and the pencil hardness was insufficient for HB and film hardness.

Comparative Example 13
In the preparation of the coating liquid (A) having the reaction product (A), an antifogging article was obtained in the same procedure as in Example 1 except that polyethylene glycol having an average molecular weight of 200 was used, and evaluated by the above method. It was. The results are shown in Table 2.
As shown in Table 2, the obtained article was an article showing no antifogging property.

Comparative Example 14
In the preparation of the coating liquid (A) having the reaction product (A), an antifogging article was obtained in the same procedure as in Example 1 except that polyethylene glycol having an average molecular weight of 10,000 was used, and evaluated by the above method. It was. The results are shown in Table 2.
As shown in Table 2, the obtained article is cloudy and has a problem in appearance, and even in the traverse test, the film is damaged after 2000 reciprocations, and the pencil hardness is H and the film hardness is insufficient. there were.

Claims (3)

A coating solution for forming an antifogging film prepared from three kinds of raw materials for preparation,
The three preparation raw materials are:
A raw material (I) containing a reaction product (A) of an isocyanate component having an isocyanate group and a water-absorbing polyol having a number average molecular weight of 400 to 5000,
A raw material (II) containing a hydrolyzed polycondensate (B) of a plurality of silicon oxide precursors (b), and
Consists of raw material (III) containing metal oxide ultrafine particles (C),
The ratio of the reaction product (A) to the total amount of the reaction product (A), the hydrolysis polycondensation product (B) and the metal oxide ultrafine particles (C) is 25 to 40% by weight, and the hydrolysis polycondensation product ( The proportion of B) is 21 to 50% by weight, the proportion of the metal oxide ultrafine particles (C) is 25 to 45% by weight,
The ratio of the tetraalkoxysilane (b1) to the total amount of the plurality of silicon oxide precursors (b) is 14 to 27% by weight, the ratio of the alkyl group-containing trialkoxysilane (b2) is 14 to 27% by weight, epoxy The coating solution for forming an antifogging film, wherein the ratio of trialkoxysilane (b3) containing at least one of a group, a mercapto group and an amino group is 46 to 72% by weight. An antifogging film formed on a substrate using the coating solution for forming an antifogging film according to claim 1,
In the antifogging film, the reaction product (A) and the hydrolysis polycondensation product (B) form a chemical bond,
The chemical bond is obtained from an isocyanate group remaining in the reaction product (A) and at least one of an epoxy group, a mercapto group, and an amino group present in the hydrolysis polycondensate (B). An antifogging film characterized by being formed. A method for forming an antifogging film according to claim 2,
Antifogging by mixing raw material (I) containing reaction product (A), raw material (II) containing hydrolysis polycondensate (B), and raw material (III) containing ultrafine metal oxide (C) A step of obtaining a coating liquid for forming a conductive film,
Applying the coating solution for forming the anti-fogging film on a substrate; and
A method for forming an antifogging film, comprising a step of heating a coating layer coated on the substrate.