JP3004795B2 - Method of using antifogging film and antifogging structure of transparent molded product - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for using an antifogging film for preventing surface fogging of a glass molded article, a plastic molded article, and the like, and to an antifogging structure of a transparent molded article.

[0002]

2. Description of the Related Art In general, inorganic glass, polycarbonate resin, polymethyl methacrylate resin, polyvinyl chloride resin, cellulose ester resin, polystyrene resin, poly (diethylene glycol bisallyl carbonate) resin, etc., take advantage of their excellent transparency. It is widely used as a material for window glass (glazing), helmet shields, ski goggles, underwater glasses, industrial safety glasses, mirrors, and the like. However, in these transparent molded products, when the surface temperature is lower than the dew point temperature, moisture in the atmosphere becomes fine water droplets and condenses on the surface, impairing the visual field,
There is a critical problem.

[0003] In order to solve this problem, various antifogging methods have been proposed. For example, a method in which a surfactant is added to the above various transparent resins, or a method in which these are applied to the surface of glass or a dew-condensing synthetic resin, or a film is applied. A conventional antifogging film is obtained by coating the above coating agent on a polyethylene terephthalate film.

[0004]

However, since the coating layer swells due to water absorption and stress is significantly applied to the film, warpage is remarkable. Further, since the polyethylene terephthalate film itself has a certain degree of hygroscopicity, when one surface has a higher humidity than the other surface, it expands due to moisture absorption and warps. Therefore, in the conventional anti-fog film, it is necessary to provide a strongly tacky pressure-sensitive adhesive layer or fix the film with an adhesive to hold the film firmly and suppress the warpage of the film. That is, since the conventional anti-fog film is a strongly adhesive pressure-sensitive adhesive and is bonded to a transparent product such as glass or plastic products, even if the anti-fog layer absorbs water and swells, it peels off due to warpage of the film. Is less likely to occur. However, during the use of the anti-fogging film, the anti-fogging film may be stained, partially damaged, or deteriorated in anti-fogging property, so that it may be necessary to replace the anti-fogging film. But,
The anti-fogging film is very hard to peel off because it is strongly adhered to the transparent molded article. Further, even if it can be peeled off, the adhesive remains on the surface, which is not preferable.

An object of the present invention is to provide a method of using an anti-fogging film which is hardly warped or deformed by water absorption, can be fixed to the surface of a transparent molded article without a strong adhesive, and can be easily peeled off. It is to provide an anti-fog structure.

[0006]

SUMMARY OF THE INVENTION The present invention provides a method for preventing fogging of a transparent molded article by using an antifogging film.
The anti-fog film comprises a polycarbonate film having a thickness of 50 to 150 μm, and a hydrophilic anti-fog layer formed on the anti-fog surface of the polycarbonate film by curing an active energy ray-curable hydrophilic anti-fog agent. The thickness of the hydrophilic anti-fog layer is 10% or more and 40% or less of the thickness of the polycarbonate film, and the non-fog surface of the polycarbonate film without the hydrophilic anti-fog layer and the surface of the transparent molded product At least one of which is wetted with a liquid, and a non-fog-preventing surface is attached to the surface of the transparent molded article to prevent the transparent molded article from fogging.

The present invention also provides a transparent molded product having a transparent molded product and an antifogging film adhered to the surface of the transparent molded product, wherein the antifogging film comprises:
A polycarbonate film having a thickness of 50 to 150 μm, and a hydrophilic antifogging layer formed by curing an active energy ray-curable hydrophilic antifogging agent on the antifogging surface of the polycarbonate film. The thickness of the polycarbonate film is not less than 10% and not more than 40% of the thickness of the polycarbonate film, and at least one of the non-fogging surface of the polycarbonate film on which the hydrophilic anti-fogging layer is not provided and the surface of the transparent molded product is liquid. The present invention relates to an anti-fog structure of a transparent molded article, which is obtained by adhering a non-fog-preventing surface to a surface of a transparent molded article in a state of being wetted with a liquid.

[0008]

The present inventor has proceeded with research focusing on the following points.
The present invention has been completed. The cause of the warpage of the conventional antifogging film is that both the antifogging layer and its supporting film use a material having a relatively large water absorbency. However, when the supporting film is non-water-absorbing and has a large proportion of the total thickness, the warping phenomenon of the film should be greatly reduced. As a result of specifically pursuing this point, the thickness of the hydrophilic anti-fog layer having water absorption is set to 40% or less of the thickness of the non-water-absorbing polycarbonate film, and by combining these, the anti-fogging film due to the difference in humidity is produced. Warpage was greatly reduced.

The polycarbonate film has extremely low hygroscopicity and does not warp due to humidity. However, on the other hand, the polycarbonate film has a high surface activity and a high adhesive force to the surface of glass, mirrors and various plastics. This adhesive force, adhesive,
Peel strength is lower than that of the surface where an adhesive or the like is applied and adhered. However, if the non-fog-proof surface or glass surface of the polycarbonate film is wetted with a liquid and this non-fog-proof surface is directly adhered to the glass surface or plastic surface, it will withstand its own weight and some wind force, and may peel off. The inventor has discovered that there is no such thing. As a result, even after the non-fogging film is fixed, it can be relatively easily peeled off and replaced as needed. Moreover, no adhesive or dirt remains on the side of the transparent molded product.

[0010] Moreover, such an attaching method can be implemented for the first time since the warpage of the anti-fogging film can be suppressed as described above. Even if the conventional antifogging film is attached to the surface of glass or the like without an adhesive, if the antifogging film is warped, it will immediately peel off.

The thickness of the polycarbonate film is preferably 50 to 150 μm in consideration of the ease of sticking determined by physical properties such as flexibility and rigidity. This is 50μm
When it is less than 150 μm, the rigidity of the polycarbonate film is low, and when it exceeds 150 μm, the flexibility becomes low and it becomes difficult to attach. Moreover, in addition to the limitation of the thickness, there is no possibility that the polycarbonate film is wrinkled or bubbles are generated at the time of sticking as compared with the case where an adhesive is used, so that the sticking is easier.

[0012] Also, among many transparent plastics,
In particular, the polycarbonate film is a highly rigid film with excellent transparency, water resistance, impact resistance, etc., and has one side that has little moisture absorption even under high humidity, so it does not warp and is suitable as a support for anti-fogging film I have.

In the present invention, an active energy ray-curable anti-fog agent is applied to one surface of a polycarbonate film, and the applied layer is cured to form a hydrophilic anti-fog layer. This is preferable from the viewpoint of energy saving, no pollution, high productivity, low total cost, and the like, and is excellent in the balance between surface hardness and antifogging property.

The active energy ray-curable hydrophilic antifog agent is
There is no particular limitation on the type of compounding, but in consideration of coatability, curability, curing shrinkage, colorless transparency, odor, etc., hydrophilic (meth) acryloyl group-containing monomer, hydrophilic (meth) acryloyl Known raw materials such as group-containing oligomers, ene / thiol reactive monomers or (and) oligomers, cationically polymerizable monomers or (and) oligomers, surfactants, photopolymerization initiators, etc., are selected and prepared in combination. Is used.

The hydrophilic (meth) acryloyl group-containing monomer and the hydrophilic (meth) acryloyl group-containing oligomer are components for adjusting the crosslinking, water absorption, water affinity, surface hardness and the like of the anti-fog layer. is there. Examples of the hydrophilic (meth) acryloyl group-containing monomer include the following. 2-hydroxyethyl (meth) acrylate, 2-
Hydroxypropyl (meth) acrylate, 1,4-butanediol mono (meth) acrylate, glycerol mono (meth) acrylate, caprolactone-modified (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, polyethylene Glycol-polypropylene glycol block copolymer mono (meth) acrylate, ethylene oxide-modified phthalic acid monoacrylate, ethylene oxide-propylene oxide-modified phthalic acid mono (meth) acrylate, epichlorohydrin-modified butyl acrylate, 2-hydroxy-
Mono (meth) acrylate compounds containing at least one hydroxyl group, such as 3-methacryloxyprotrimethylammonium chloride.

Triglycerol diacrylate, glycerin monoacrylate monomethacrylate, glycerol di (meth) acrylate, pentaerythritol triacrylate, dipentaerythritol monohydroxypentaacrylate, epichlorohydrin modified glycerol triacrylate, epichlorohydrin modified 1,
6-hexanediol diacrylate, epichlorohydrin-modified propylene glycol diacrylate, epichlorohydrin-modified trimethylpropane triacrylate, epichlorohydrin-modified phthalic acid diacrylate,
And di- or tri (meth) acrylate compounds containing at least one hydroxyl group. Dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate,
(Meth) acrylates containing an amino group. Acrylamide such as morpholine acrylamide, diacetone acrylamide, N-methylol acrylamide. (Meth) acrylates containing a carboxyl group such as ethylene oxide-modified phthalic acid (meth) acrylate and ethylene oxide-modified succinic acid (meth) acrylate. N-vinyl-2-pyrrolidone, N-vinylcaprolactam. These hydrophilic (meth) acryloyl-containing monomers are
One type or two or more types may be used in combination.

Examples of hydrophilic (meth) acryloyl group-containing oligomers include polyester-type urethane (meth) acrylates having an ethylene oxide block chain in the main chain, and polyether-type urethanes having an ethylene oxide block chain in the main chain ( Urethane (meth) acrylate such as (meth) acrylate.

When higher antifogging properties are required, an antifogging oligomer represented by the following general formula is used. The following antifogging oligomers are wetting for antifogging properties, balance between hydrophobic groups and hydrophilic groups for water resistance,
It is a novel antifogging urethane (meth) acrylate oligomer capable of adjusting the crosslinking density and the like.

[0019]

Embedded image

[0020] [P _1, P ₂ is a group given by removing hydroxyl groups of the respective alcohol compound having a hydroxyl group one group, and P ₁
At least one of the P ₂ includes an acryloyl group or a methacryloyl group, P ₃ is a group given by removing hydroxyl groups of the polyol compound, wherein P _1, at least one polyethylene oxide block of the P _2, P ₃

Embedded image (N is an integer of 5-200). T is a residue of the triisocyanate compound excluding the isocyanate group, and m is the number of repeating units of 0 to 20. ]

These hydrophilic (meth) acryloyl group-containing oligomers are used alone or in combination of two or more.

The surfactant serves to reduce the surface tension of water droplets, and commercially available nonionic, anionic and cationic surfactants can be used. Also, as a special one, nonionic fluorocarbon surfactants,
Photopolymerizable phosphoric acid group-containing polyethylene glycol mono (meth) acrylate can also be used. One or more surfactants are used in combination.

When an ultraviolet ray is used as the active energy ray, the photopolymerization initiator has a role of generating a radical by irradiating the ultraviolet ray and initiating polymerization of a (meth) acryloyl group, and is an essential component. However, it is not particularly necessary for curing with an active energy ray other than ultraviolet rays, for example, an electron beam or a cobalt ray.

As the photopolymerization initiator, for example, diethoxyacetophenone, 2-hydroxy-2-methyl-1-
Phenylpropan-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropane-1
Acetophenones such as -one, 4- (2-hydroxyethoxy) -phenyl (2-hydroxy-2-propyl) ketone, benzoin, benzoin methyl ether,
Benzoin series such as benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-2-phenylacetophenone, benzophenone, hydroxybenzophenone, 3,
Benzophenones such as 3-dimethyl-4-methoxybenzophenone, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, thioxanthones such as 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, isopropylthioxanthone, and 1-phenyl -1,2-propanedione-2- (o-ethoxycarbonyl) oxime, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, methylphenylglyoxylate, benzyl and the like. One or more photopolymerization initiators are used in combination. or,
A photopolymerization sensitizer may be used in combination with these photopolymerization initiators in order to adjust curability.

The above active energy ray-curable hydrophilic antifog agent is a liquid having a relatively low viscosity, and can be applied even without adding a solvent. This means that a solvent drying step is not particularly required in the processing line, which is extremely advantageous. However, a solvent may be added for the purpose of adjusting the film thickness and improving the mirror surface even more. In this case, as a solvent that can be used, ethanol,
Alcohols such as isopropanol and n-butanol,
Cellsolves such as methylcellsolve, ethylcellsolve and butylcellsolve are preferred.

In order to coat the polycarbonate film with the antifogging agent, any coating method is employed.
For example, any method such as spraying, dipping, flow coating, roll coating, bar coating, curtain flow, spin coating, screen printing, etc. may be used. Immediately after painting or after setting for several minutes, by irradiating active energy rays such as ultraviolet rays,
A cured film is formed. The UV irradiation device used is 25
A high-pressure mercury lamp that emits ultraviolet light having a wavelength of 0 to 400 nm is suitable. Standard irradiation conditions are lamp output 80-120w / cm
, Ramp distance 5-30cm, conveyor speed 1-10m / min
The degree is preferred.

The thickness of the anti-fog layer is at least 10% and at most 40% of the thickness of the polycarbonate film. If the thickness is less than 10%, the water absorption becomes poor, the anti-fogging property decreases,
Not preferred. On the other hand, if the thickness exceeds 40%, the stress moves to the polycarbonate film due to water absorption, and warpage occurs, which is not preferable.

In order to bond the thus obtained antifogging film of the present invention to a transparent product such as glass or plastic product, water or a surfactant solution (transparent product) is applied to the adherend (transparent product). It is preferred to apply a liquid such as soapy water) and bond the non-fog-preventing surface of the polycarbonate film so that bubbles do not enter therein, and remove the liquid while squeezing and sticking.

[0029]

The present invention will be described below in more detail with reference to examples. (Synthesis Example of New Antifogging Urethane Acrylate Oligomer A: Example of m = 3) In a 11-volume reactor equipped with a stirrer and a reflux condenser, "Mytec 21" was added as triisocyanate.
5A "(manufactured by Mitsubishi Kasei Corporation, isocyanate adduct obtained by adding 3 mol of isophorone diisocyanate to trimethylolpropane, molecular weight 800, solid content 75% ethyl acetate solution)
A solution in which 56.89 g was previously dissolved in 80 g of ethyl acetate was added. The N ₂ gas was replaced while stirring, and the temperature was raised to 50 ° C. and kept constant. Next, 6.19 g of 2-hydroxyethyl acrylate (hereinafter abbreviated as HEA) as an alcohol having a (meth) acryloyl group, 0.84 g of dibutyltin dilaurate (hereinafter abbreviated as DBTDL) as a urethanization catalyst, and 18 g of ethyl acetate Was added, and the mixture was reacted at a temperature of 50 ° C. for 3 hours.

Next, as a glycol compound, 234.7 g of "Newpol PE-68" (manufactured by NOF CORPORATION, ethylene oxide-propylene oxide block copolymer, Mw 8800, hereinafter abbreviated as "PE-68") was added to 234.7 g of ethyl acetate. g, and the mixture was reacted for 2 hours while maintaining the temperature at 50 ° C.

Further, 117.3 g of the remaining “PE-68” and “HEA
A solution of 3.09 g in 120.12 g of ethyl acetate was added, and the mixture was reacted at 60 ° C. for 5 hours. 2250 by IR measurement
After confirming that the characteristic absorption of NCO appearing in cm ^-1 had disappeared, the reaction was terminated, and the temperature was returned to 25 ° C. The reaction solution was placed in a vacuum dryer, kept at 50 ° C., and depressurized with a vacuum pump to remove ethyl acetate, thereby obtaining a white solid oligomer. This oligomer is referred to as “oligomer A”.

(Preparation of anti-fogging agent) Each compounding agent shown in the following Table 1 was mixed to produce ultraviolet curable anti-fogging agents A, B, C, D and E. However, each numerical value in Table 1 represents the amount of each compounding agent added in “parts by weight”. The components in Table 1 are as follows. Urethane acrylate 1: "Aronix M-1200"
(Toa Gosei Chemical Co., Ltd.), bifunctional, non-yellowing type urethane acrylate Urethane acrylate 2: "Shikko 7000B" (Nippon Synthetic Chemical Co., Ltd.), non-yellowing type urethane acrylate "D-1173": "Darocur 1173" (Merck) Photopolymerization initiator Oligomer A: as described above

[0033]

[Table 1]

(Production of antifogging film) A polycarbonate film or a polyethylene terephthalate film having a predetermined thickness shown in the following table was prepared. Then, an antifogging agent A, B, C, D or E was applied to the surface of each support film using an applicator, and this applied layer was cured by irradiating ultraviolet rays. As the ultraviolet irradiation device, “ORM-2077A” (manufactured by Oak Manufacturing Co., Ltd., high-pressure mercury lamp 80 W / cm * 3 lamps, lamp distance 15 cm) was used. UV integrated light amount is 1000
mJ / cm ² .

(Evaluation of Antifogging Film) Each of the obtained antifogging films was adhered to a glass surface of a mirror with water. That is, the non-fogging surface of each anti-fogging film and the glass surface were wetted with water, the anti-fogging film was attached, and water was extruded from the space while pressing the anti-fogging film with a finger to fix the film. . The following properties of the anti-fogging film in this state were evaluated. The results are shown in the table.

(Transparency) Measured with a total light transmittance meter.
In the case of a transmittance of 90% or more, it was evaluated as “○”. Less than 90% 70%
In the case of the above transmittance, it was set to “△”. When the transmittance was less than 70%, it was evaluated as “x”. (Cross hatch test) Using a cutter knife, 100 goban eyes at 1 m / m were made, and a cellotape peeling test was performed to check the number of remaining gobang eyes. If there is no peeling,
"100/100" and total peeling were "0/100". In addition, (after water resistance), the sample was immersed in warm water at 80 ° C., the water was wiped off with a rag, and immediately thereafter, the test was performed in the same manner. (Direct steam test) A sample was prepared by applying an anti-fog film to a glass plate with water, and steam at 50 ° C was directly applied to the anti-fog surface of the film for 30 minutes to check for occurrence of warpage. When there was no warpage, it was evaluated as “○”. When warpage occurred, it was evaluated as “×”.

(Anti-fogging property) A test was conducted under the same conditions as in the (direct steam test), and the occurrence of fogging was visually observed. When no fogging occurred, “○” was given, and when fogging occurred, “×” was given. (Ease of Peeling) After the above direct steam test, it was left to cool to room temperature, peeled off by hand, and a sensory test for ease of peeling was made by three persons. The case where peeling was possible with a weak force was rated as “○”, and the case where peeling was impossible without applying a strong force was rated as “x”. (Ease of Attaching) A sensory test was conducted by three persons on the ease of applying water on the glass surface. A case where no air bubbles were mixed between the anti-fogging film and the glass surface and the water film was thin and easy to attach was designated as “○”. When a certain amount of pressure is required, "△" is used. A mark of "x" was given when air bubbles were easily mixed or it was difficult to thin the water film by wiping the antifogging film with a finger.

[0038]

[Table 2]

[0039]

[Table 3]

As can be seen from the results shown in the table, first, the polyethylene terephthalate film has poor transparency. In the cross hatch test, each example was good, and sufficient adhesion strength was obtained. When a polyethylene terephthalate film is used, the antifogging film is peeled off because of a large warp. When the thickness of the polycarbonate film is 50 to 150 μm, the antifogging film can be easily attached. Comparative Examples 13 and 14 having a thick antifogging layer
Then you can see the warpage.

[0041]

As described above, according to the method for using the antifogging film of the present invention and the antifogging structure of a transparent molded product,
The antifogging film can be stuck and fixed on the surface of a transparent molded article without warping of the antifogging film due to a change in humidity and without a strong adhesive or adhesive. Even if the anti-fogging film is fixed in this way, the anti-fogging film does not warp, so that the stress caused by the warping does not cause the anti-fogging film to peel off. Therefore, the antifogging film can be relatively easily peeled off and replaced.

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C08J 7/00-7/18 B32B 7 / 02,27 / 36

Claims (2)

(57) [Claims] 1. A method for preventing fogging of a transparent molded article by using an anti-fogging film, wherein the anti-fogging film comprises a polycarbonate film having a thickness of 50 to 150 μm and an anti-fogging surface of the polycarbonate film. A hydrophilic anti-fog layer formed by curing an active energy ray-curable hydrophilic anti-fog agent, the thickness of the hydrophilic anti-fog layer being the thickness of the polycarbonate film.
10% or more and 40% or less, and wet at least one of the non-fogging surface of the polycarbonate film on which the hydrophilic anti-fogging layer is not provided and the surface of the transparent molded article with the liquid. Affixing a surface to the surface of the transparent molded article to prevent fogging of the transparent molded article,
How to use anti-fog film. 2. An antifogging structure of a transparent molded article comprising a transparent molded article and an antifogging film adhered to the surface of the transparent molded article, wherein the antifogging film has a thickness of A polycarbonate film having a thickness of 50 to 150 μm, and a hydrophilic anti-fog layer formed by curing an active energy ray-curable hydrophilic anti-fog agent on the anti-fog surface of the polycarbonate film. Is the thickness of the polycarbonate film
10% or more and 40% or less, wherein the non-fog surface of the polycarbonate film on which the hydrophilic anti-fog layer is not provided and at least one of the surface of the transparent molded article are wetted with a liquid. An antifogging structure for a transparent molded article, which is obtained by attaching an antifogging surface to the surface of the transparent molded article.