JP7057679B2 - Method for manufacturing hard coat liquid and hard coat layer - Google Patents

Description

The present invention relates to a hard coat liquid and a method for producing a hard coat layer.

In recent years, there has been an increasing movement to use transparent resin plates in place of conventional inorganic glass plates as windowpanes for vehicles such as automobiles and windowpanes for building materials attached to buildings such as houses and buildings. In particular, in vehicles such as automobiles, it has been proposed to use a transparent resin plate for the window material in order to reduce the weight. In particular, the aromatic polycarbonate-based transparent resin plate is fracture-resistant, transparent, lightweight, and easy. Since it has excellent workability, its use as a promising vehicle window material is being considered. However, such a transparent resin plate has a problem in terms of scratch resistance and weather resistance when used as it is instead of a glass plate.

Therefore, for the purpose of improving the scratch resistance and weather resistance of the transparent resin plate, it has been proposed to form a film on the surface of the transparent resin plate by using various hard coating agents, particularly silicone-based hard coating agents. When forming a film (hardcoat layer) on a transparent resin plate using a silicone-based hardcoat agent, a primer layer should be used in order to improve the adhesion between the hardcoat layer and the transparent resin plate. Has been proposed.

Patent Document 1 describes a resin substrate with a hardcoat film in which a silicone-based hardcoat layer is formed on a resin substrate via a primer layer, which has excellent scratch resistance and weather resistance to the hardcoat layer. A resin substrate with a hardcourt film, which is also excellent in weather resistance such as weather crack resistance, is disclosed. That is, it is a resin substrate with a hard coat coating having a prima layer, an intermediate layer, and a hard coat layer in this order from the resin substrate side on at least one surface of the resin substrate, and the prima layer contains an acrylic polymer as a main component. The hard coat layer contains the cured product of organopolysiloxane as a main component, and the intermediate layer contains the acrylic polymer and the cured product of the organopolysiloxane as main components. A resin substrate with a hard coat film having an Mt / Ht of 0.05 to 1.0 when the thickness of the intermediate layer is Mt and the thickness of the hard coat layer is Ht has been proposed.

Further, in Patent Document 1, in the hard coat agent composition for forming a hard coat layer, organopolysiloxane which is an essential component and various additives which are optional components are usually dissolved and dispersed in a solvent. It is prepared in the form of Further, all the non-volatile components in the hard coat agent composition need to be stably dissolved and dispersed in a solvent, and for that purpose, the solvent should be at least 20% by mass or more, preferably 50% by mass or more of alcohol. It is stated that it should be included.

International Publication 2011/078178 Pamphlet

However, in the resin substrate with a hard coat film described in Patent Document 1, a hard coat agent composition using an alcohol as a solvent is applied on an acrylic prima layer to form a hard coat layer. As a result, an organic solvent such as alcohol dissolves the acrylic primer layer and roughens the once formed primer layer, resulting in deterioration of the adhesion between the primer layer and the hard coat layer or a hard coat film. There is a problem that the appearance of the resin substrate is spoiled.

In view of the above problems, as a result of diligent studies, the present inventor has determined the adhesion to the polyacrylic acid ester derivative without roughening the surface of the resin made of the polyacrylic acid ester derivative by controlling the solvent ratio in the drying process. It has been found that an excellent hard coat layer can be formed, and the present invention has been reached.

That is, the present invention is a hardcoat liquid capable of forming a hardcoat layer having excellent adhesion to a polyacrylic acid ester derivative without roughening the surface of a polyacrylic acid ester derivative such as an acrylic prima layer, and the like. It is an object of the present invention to provide a method for producing a hardcoat layer using a hardcoat liquid.

In order to achieve the above object, the hard coat liquid of the present invention is a hard coat liquid for forming a hard coat layer that protects the surface of a resin made of a polyacrylic acid ester derivative.
The hard coat liquid is composed of a solute component and a solvent component containing water and a protonic organic solvent. The protonic organic solvent has a high boiling point solvent having a boiling point of more than 100 ° C. and a low boiling point having a boiling point of less than 100 ° C. It is composed of a solvent, and the content of the high boiling point solvent in the whole solvent component is 30 to 50% by weight, the content of the low boiling point solvent is 25 to 50% by weight, and the content of water is 10 to 30% by weight. It is characterized by.

In order to form a hardcoat layer having excellent adhesion to the resin made of the polyacrylic acid ester derivative, it is necessary to form an intermediate layer having excellent adhesion to both the polyacrylic acid ester derivative and the hardcoat layer. be. The intermediate layer is a layer formed by mixing a polyacrylic acid ester derivative and a resin constituting the hard coat layer, and has both components, so that it has good adhesion to the polyacrylic acid ester derivative and the hard coat layer. Excellent.

If the organic solvent in the hardcoat liquid does not dissolve the resin, it cannot penetrate into the polyacrylic acid ester derivative in the first place and the intermediate layer cannot be formed. On the other hand, if the content of the organic solvent is not set appropriately, the solubility of the polyacrylic acid ester derivative becomes high, and as a result of roughening the surface of the polyacrylic acid ester derivative, the adhesion between the prima layer and the hard coat layer becomes adhesive. Is deteriorated, and the appearance of the resin plate having the hard coat layer is impaired.

However, according to the hard coat liquid of the present invention, since the water content is 10% by weight or more, the solvent component containing the protonic organic solvent is poly at the stage where the viscosity of the hard coat liquid at the initial stage of drying is low. It does not roughen the surface of the resin made of the acrylic acid ester derivative. Further, since the content of water is 30% by weight or less, water volatilizes together with the protonic organic solvent in the drying process and does not easily remain, and adverse effects such as phase separation of solute components occur in the drying process. Can be prevented.

Further, since the content of the low boiling point solvent is 25% by weight or more and the content of the high boiling point solvent is 50% by weight or less, the solute component can be sufficiently dissolved at the stage of the hard coating liquid before coating, and the solute component can be uniformly dissolved. A hard coat solution having a different composition can be prepared.
Further, since the content of the low boiling point solvent is 50% by weight or less and the content of the high boiling point solvent is as high as 30% by weight or more, the content of the high boiling point solvent is contained even if the liquid component is evaporated in the drying step. The rate does not decrease, and the state of the hard coat liquid having high viscosity can be maintained up to a high temperature while leaving the high boiling point solvent.
In this way, through the drying process, the ratio of water and the protonic organic solvent evaporates in a balanced manner, and in the final stage, the ratio of the protonic organic solvent increases, and the intermediate layer is formed while melting the surface of the resin made of the polyacrylic acid ester derivative. Form.

In addition, the viscosity of the hardcourt liquid in the drying process is affected by two factors: an increase in viscosity due to evaporation of the solvent and an increase in viscosity due to condensation of the solute. The increase in viscosity associated with the condensation of the solute is manifested only at a constant temperature without evaporation of the solvent. Due to this effect, in the drying process, a hard coat layer swelled with a solvent and gelled is formed on the resin surface, and since it is gelled, infiltration of the polyacrylic acid ester into the resin surface is suppressed and a gel state is formed. The hard coat liquid can slowly infiltrate the surface of the resin made of the polyacrylic acid ester derivative. As a result, a hard coat layer having a high hardness can be formed, and an intermediate layer having both a hard coat layer and a component of the polyacrylic acid ester derivative without roughening the surface of the resin made of the polyacrylic acid ester derivative. Is thought to be able to form.

In the hard coat liquid of the present invention, the protonic organic solvent is preferably composed of an alcohol or a carboxylic acid.
The alcohol or the carboxylic acid has an appropriate solubility in a resin made of a polyacrylic acid ester derivative, and is in the middle of an appropriate thickness without excessively dissolving the resin made of a polyacrylic acid ester derivative. Layers can be formed. Moreover, these solvents are easy to mix with water, and it is easy to adjust the solubility in the resin made of the above-mentioned polyacrylic acid ester derivative.

In the hard coat liquid of the present invention, the solute component is preferably composed of a silicone-based component.
The silicone-based component can form a hard film, and the raw material before condensation is easily dissolved in a protonic organic solvent, so that it can be suitably used as the hard coat liquid of the present invention.

In the hard coat liquid of the present invention, the silicone-based component preferably contains siloxane.
Since the siloxane component can form a hard film of polysiloxane by condensation, it can be suitably used as a hard coat liquid for forming a hard coat layer.

In the hard coat liquid of the present invention, the solute component preferably contains ceramic particles.
When the hard coat liquid of the present invention contains ceramic particles, the hard coat layer contains ceramic particles, so that a harder hard coat layer can be formed.

The method for producing a hardcoat layer of the present invention is characterized in that the hardcoat liquid is applied to the surface of a resin made of a polyacrylic acid ester derivative and dried.
In the method for producing a hard coat layer of the present invention, the above-mentioned hard coat liquid is applied to the surface of a resin made of a polyacrylic acid ester derivative and dried to obtain a hard hard coat on the surface of the resin made of a polyacrylic acid ester derivative. A layer can be formed, and an intermediate layer having adhesion to a resin made of a polyacrylic acid ester derivative and a hard coat layer can be formed.

FIG. 1 is a cross-sectional view schematically showing a translucent plate formed by using the hard coat liquid of the present invention and having a primer layer and a hard coat layer formed on a substrate.

(Detailed description of the invention)
The hard coat liquid of the present invention is a hard coat liquid for forming a hard coat layer that protects the surface of a resin made of a polyacrylic acid ester derivative.
The hard coat liquid is composed of a solute component and a solvent component containing water and a protonic organic solvent. The protonic organic solvent has a high boiling point solvent having a boiling point of more than 100 ° C. and a low boiling point having a boiling point of less than 100 ° C. It is composed of a solvent, and the content of the high boiling point solvent in the whole solvent component is 30 to 50% by weight, the content of the low boiling point solvent is 25 to 50% by weight, and the content of water is 10 to 30% by weight. It is characterized by.

According to the hard coat liquid of the present invention, the water content is 10% by weight or more. Therefore, at the stage where the viscosity of the hard coat liquid at the initial stage of drying is low, the solvent component containing the protonic organic solvent is polyacrylic acid. It does not roughen the surface of the resin made of the ester derivative. In addition, since the content of water is 30% by weight or less, water volatilizes together with the protonic organic solvent in the drying process and does not easily remain, preventing adverse effects such as phase separation of solute components in the drying process. can do.

Further, since the content of the low boiling point solvent is 25% by weight or more and the content of the high boiling point solvent is 50% by weight or less, the solute component can be sufficiently dissolved at the stage of the hard coat liquid before coating, and further. Since the content of the low boiling point solvent is 50% by weight or less and the content of the high boiling point solvent is as high as 30% by weight or more, the content of the high boiling point solvent is high even if the liquid component is evaporated in the drying step. Is not low, and the state of the hard coat liquid having high viscosity can be maintained up to a high temperature while leaving a high boiling point solvent.
In this way, through the drying process, the ratio of water and the protonic organic solvent evaporates in a balanced manner, and in the final stage, the ratio of the protonic organic solvent increases, and the intermediate layer is formed while melting the surface of the resin made of the polyacrylic acid ester derivative. Form.

In addition, the increase in viscosity accompanying the condensation of the solute causes the hard coat liquid to swell and gel with the solvent, suppressing the infiltration of the polyacrylic acid ester into the resin surface, and the gel-like hard coat liquid slowly becomes polyacrylic acid. It can penetrate the surface of a resin made of an acid ester derivative. As a result, the hard coat layer can be formed without roughening the surface of the resin made of the polyacrylic acid ester derivative, and at the same time, it has both the components of the hard coat layer and the polyacrylic acid ester derivative and adheres to both. It is considered that an intermediate layer having excellent properties can be formed.

The content of the high boiling point solvent in the whole solvent component is preferably 30 to 35% by weight, the content of the low boiling point solvent is preferably 40 to 50% by weight, and the content of water is preferably 20 to 25% by weight.

Examples of the polyacrylic acid ester derivative include polymethyl methacrylate, polymethyl acrylate, polyethyl methacrylate, polyethyl acrylate, polybutyl methacrylate, poly 2-ethylhexyl methacrylate, polyhexyl methacrylate, polycyclohexyl methacrylate, polyoctyl methacrylate, and polyphenyl. Examples thereof include methacrylate, polybenzyl methacrylate, polytrifluoroethyl methacrylate, polypentafluoropropyl methacrylate and the like. Among these, polymethylmethacrylate is preferable.
The number average molecular weight of the polyacrylic acid ester derivative is preferably more than 2000 and preferably 100,000 or less.

The form of the resin composed of the polyacrylic acid ester derivative is not particularly limited, and any form can be used. For example, a plate-like body may be used as a resin made of a polyacrylic acid ester derivative such as polymethyl methacrylate, and a hard coat liquid may be directly applied to the plate-like body to form a hard coat layer, or another type of group may be formed. A primer solution containing a polyacrylic acid ester derivative may be applied to a material to form a prima layer made of a polyacrylic acid ester derivative, and a hard coat solution may be applied thereto to form a hard coat layer. Even when there is no adhesive force between the base material and the hard coat layer, the adhesive force between the base material and the hard coat layer can be ensured by forming a primer layer made of a polyacrylic acid ester derivative on the surface of the base material. ..

When a prima layer made of a polyacrylic acid ester derivative is formed on the surface of a base material made of a material other than the polyacrylic acid ester derivative and a hard coat layer is formed on the prima layer, the material of the base material is metal, ceramic, or resin. Etc. can be used, and the type is not particularly limited. However, since the hardcoat layer is formed for the purpose of forming the hardcoat layer and protecting the surface, the base material is preferably a resin, and is a transparent resin for the purpose of preventing scratches. Is desirable. Therefore, examples of the base material include polycarbonate, vinyl chloride, polyethylene terephthalate, high-density polyethylene, and the like.

The hardcourt liquid contains, as the protonic organic solvent, a high boiling point solvent having a boiling point of more than 100 ° C. and a low boiling point solvent having a boiling point of less than 100 ° C.
Examples of the low boiling point solvent include methanol (boiling point 65 ° C.), ethanol (boiling point 78 ° C.), isopropyl alcohol (boiling point 83 ° C.), t-butyl alcohol (boiling point 83 ° C.) and the like. These solvents have high solubility of the silicone-based component, which is one of the solutes, and can dissolve many solutes.

When a resin base material is used as the high boiling point solvent and a primer layer made of a polyacrylic acid ester derivative is formed on the surface of the resin base material, the high boiling point solvent is used from the viewpoint of preventing deterioration and softening of the base material due to heat. The boiling point is preferably equal to or lower than the softening point of the resin constituting the base material. For example, when a prima layer made of polymethyl methacrylate is formed on a polycarbonate substrate and a hard coat layer is formed on the prima layer, the boiling point of the high boiling point solvent that can be used in the hard coat liquid is the softening point of the polycarbonate (the softening point of the polycarbonate. It is preferably lower than 140 ° C.). It should be noted that even if the primer layer becomes soft, it does not affect the overall deformation, so that the softening point of the primer layer does not need to be particularly considered.

Examples of the high boiling point solvent having a boiling point exceeding 100 ° C. include n-butanol (boiling point 118 ° C.), propylene glycol monomethyl ether (PGM, boiling point 121 ° C.), acetic acid (boiling point 118 ° C.) and the like. The high boiling point solvent becomes a main component remaining in the solvent in the latter half of the drying process of the hard coat liquid.

In the hard coat liquid of the present invention, as described above, the content of the high boiling point solvent in the entire solvent component is 30 to 50% by weight, the content of the low boiling point solvent is 25 to 50% by weight, and the content of water is 10. ~ 30% by weight.

If the content of the high boiling point solvent in the entire solvent component is less than 30% by weight, the content of the high boiling point solvent is too small. Therefore, the hard coat liquid is applied to the surface of the resin made of the polyacrylic acid ester derivative and then dried. If this is done, the hard coat liquid evaporates at an early stage, making it difficult to form an intermediate layer. On the other hand, when the content of the high boiling point solvent in the entire solvent component exceeds 50% by weight, the solubility of the solute component decreases in the stage before application, and the solute component cannot be sufficiently dissolved, which is caused by the hard coat liquid. Roughness is likely to occur on the surface of the resin made of the polyacrylic acid ester derivative.

When the content of the low boiling point solvent in the entire solvent component is less than 25% by weight, the content of the high boiling point solvent increases, so that the solubility of the solute component decreases in the stage before application, and the solute component is sufficiently dissolved. Roughness is likely to occur in the resin made of the polyacrylic acid ester derivative caused by the hard coating solution. On the other hand, if the content of the low boiling point solvent in the entire solvent component exceeds 50% by weight, the content of the low boiling point solvent becomes too high, so that the hard coat liquid evaporates at an early stage during drying, and the intermediate layer. Is difficult to form.

When the content of water in the entire solvent component is less than 10% by weight, the content of water is too low and the content of the protonic organic solvent becomes too high, so that the protonic organic solvent is derived from the polyacrylic acid ester derivative. The surface of the resin is roughened. On the other hand, when the water content exceeds 30% by weight, problems such as phase separation of solutes are likely to occur, and water tends to remain during drying, making it difficult to form an intermediate layer.

The solute component preferably contains a silicone-based component such as a silicone resin, and particularly preferably contains siloxane. Siloxane condenses during the drying process to form polysiloxane, which can form a hard ruptured film. The polysiloxane refers to a resin in which the main chain is mainly composed of siloxane bonds, and the side chains, functional groups and the like are not particularly limited.
The ratio of the silicone-based component to the entire hard coat liquid is preferably 24 to 35% by weight.

The solute component preferably contains ceramic particles in addition to the silicone-based component. Examples of the ceramic particles include silica, alumina, titanium oxide, zirconia and the like. The average particle size of the ceramic particles is preferably, for example, 10 to 1000 nm. The average particle size of the ceramic particles can be measured with a laser diffraction type particle size distribution measuring device. The hard coat liquid may contain a silica hybrid composite, a silica sol, or the like.
The ratio of the ceramic particles to the total amount of the silicone-based component and the ceramic particles is preferably 10 to 50% by weight.

Next, a method for manufacturing a hardcoat layer using the above hardcoat liquid will be described.
The method for producing a hardcoat layer of the present invention is characterized in that the above-mentioned hardcoat liquid is applied to the surface of a resin made of a polyacrylic acid ester derivative and dried.

Since the resin composed of the polyacrylic acid ester derivative has been described in the hard coat liquid of the present invention, the description thereof will be omitted here.
As described above, in the present invention, a hardcoat solution may be directly applied to a plate-like body made of a polyacrylic acid ester derivative such as polymethylmethacrylate to form a hardcoat layer, or poly on another type of substrate. A primer solution containing an acrylic acid ester derivative may be applied to form a prima layer made of a polyacrylic acid ester derivative, and a hard coat solution may be applied thereto to form a hard coat layer.
Here, a primer solution containing a polyacrylic acid ester derivative is applied to a substrate made of polycarbonate or the like to form a primer layer made of a polyacrylic acid ester derivative, and a hard coat solution is applied thereto to form a hard coat layer. The case of forming will be described.

In the method for producing a hard coat layer of the present invention, a primer layer is first formed on the surface of a substrate.
When forming the prima layer, a polyacrylic acid ester derivative and a solvent containing alcohol, amine, etc. are prepared, and then a prima solution is applied to the surface of the base material, and the surface is heated, dried, and cured to obtain polyacrylic acid. A prima layer made of an acid ester derivative can be formed.
The method of application is not particularly limited, and examples thereof include a spray coat and a dip coat. The drying temperature is preferably about 120 to 140 ° C., and the drying time is preferably 10 to 60 minutes.

After forming the primer layer, the hard coat liquid of the present invention is used to apply the hard coat liquid to the surface of the primer layer and dry it.
The method of coating is not particularly limited, and examples thereof include a spray coat and a dip coat, as in the primer layer forming method. The drying temperature is preferably about 100 to 140 ° C., and the drying time is preferably 10 to 80 minutes.

In the drying step, the low boiling point solvent evaporates first, followed by water and the high boiling point solvent in that order.
In this way, through the drying process, the ratio of water and the protonic organic solvent evaporates in a balanced manner, and in the final stage, the ratio of the protonic organic solvent increases, and the intermediate layer is formed while melting the surface of the resin made of the polyacrylic acid ester derivative. Form. Even in the final stage of the drying process, the content of the high boiling point solvent does not decrease, and the state of the hard coat liquid having high viscosity can be maintained up to a high temperature while the high boiling point solvent remains. In addition, the increase in viscosity accompanying the condensation of the solute causes the hard coat liquid to swell and gel with the solvent, suppressing the infiltration of the polyacrylic acid ester into the resin surface, and the gel-like hard coat liquid slowly becomes polyacrylic acid. It can penetrate the surface of a resin made of an acid ester derivative. As a result, a hard coat layer having a high hardness can be formed without roughening the surface of the resin made of the polyacrylic acid ester derivative, and the hard coat layer and the polyacrylic acid ester derivative have both components. It is possible to form an intermediate layer having excellent adhesion to both.

FIG. 1 is a cross-sectional view schematically showing a translucent plate formed by using the hard coat liquid of the present invention and having a primer layer and a hard coat layer formed on a substrate. The thickness of each layer shown in FIG. 1 is appropriately changed for the purpose of clarifying and simplifying the drawings, and does not represent the relationship between the actual thicknesses. Further, the resin plate in which the primer layer and the hard coat layer are formed on the substrate will be hereinafter referred to as a translucent plate.

The translucent plate 1 shown in FIG. 1 is composed of a resin base material 11, a primer layer 12 provided on the base material 11, and a hard coat layer 13 provided on the primer layer 12. An intermediate layer 14 is formed between the prima layer 12 and the hard coat layer 13, and the intermediate layer 14 has excellent adhesion between the prima layer 12 and the hard coat layer 13, so that the intermediate layer 14 adheres to the base material 11. It is possible to manufacture a light-transmitting plate having excellent properties.

In the above-mentioned translucent plate, the shape of the base material is not particularly limited, and in addition to a flat plate, a curved plate, a semi-cylinder, and a cylindrical shape, the shape of the outer edge of the cross section thereof is arbitrary such as an ellipse or a polygon. It may be in shape. When the translucent plate is used as glass for automobiles or the like, the base material is preferably curved in a curved surface.

In the translucent plate, the base material does not have to be colorless and may be colored.

In the translucent plate of the present invention, the surface of the base material may be roughened by sandblasting, chemicals, or the like. Even if the surface of the base material is roughened, it can be smoothed by the primer layer and the hard coat layer to prevent light from being scattered.

In the translucent plate, the thickness of the base material is preferably 1 to 10 mm.
When the thickness of the base material is within the above range, the mechanical strength when used as glass for, for example, an automobile can be ensured, and further, distortion or the like is less likely to occur in the entire light-transmitting plate.

In the translucent plate, the thickness of the primer layer is not particularly limited, but is preferably 1 to 10 μm, more preferably 2 to 5 μm, from the viewpoint of adhesiveness to the substrate and the hard coat layer.

In the translucent plate, the thickness of the hard coat layer is not particularly limited, but is preferably 1 to 10 μm, more preferably 2 to 5 μm, from the viewpoint of obtaining high surface hardness.

In the translucent plate, the thickness of the intermediate layer is preferably 0.3 to 2 μm.
When the thickness of the intermediate layer is within the above range, the adhesion between the hard coat layer and the primer layer can be enhanced.

The thickness of the primer layer, the intermediate layer and the hard coat layer can be measured from the TEM image obtained by observing the cross section of the translucent plate using a transmission electron microscope (TEM).

In the translucent plate, the primer layer and the hard coat layer may be provided on one side of the base material or may be provided on both sides. Further, a ceramic layer made of a material different from that of the hard coat layer may be provided on the hard coat layer.

The above-mentioned translucent plate is preferably used as glass for automobiles, and specifically, it is preferably used for windows, lamp covers or lamp lenses for automobiles.

Examples of windows for automobiles include front, rear, left and right windows, roofs, and the like. Above all, it is preferable to use it for the rear window.
Examples of the lamp cover include a headlamp cover, a small lamp cover, a winker cover, a fog lamp cover, a tail lamp cover, a brake lamp cover, a back lamp cover, an interior lamp cover, and the like.
Examples of the lamp lens include a head lamp lens, a small lamp lens, a winker lens, a fog lamp lens, a tail lamp lens, a brake lamp lens, a back lamp lens, an in-vehicle lamp lens, and the like, and may be integrated with a lamp cover. ..

The translucent plate is used for applications other than glass for automobiles, such as glass for transportation equipment other than automobiles such as trains, aircraft, ships, motorcycles, and bicycles (windows, lamp covers, various lamp lenses, etc.); houses, offices, etc. Glass for buildings such as buildings (windows, etc.); Can be used as covers for various types of lighting such as interior lighting (LED lighting, fluorescent lights), traffic lights, road lights, side lights, security lights, park lights, etc.

(Example)
Hereinafter, examples in which the present invention is disclosed more specifically will be shown. The present invention is not limited to these examples.

<Preparation of sample>
[Example 1]
As described below, a sample of Example 1 was prepared by forming a primer layer on the surface of a resin base material and then forming a hard coat layer.
As a base material, 100 mm × 100 mm × 5 mm polycarbonate (Carboglass (registered trademark) manufactured by Asahi Glass Co., Ltd.) was prepared.
The substrate is dipped in a tank filled with an acrylic primer (470 FT 2050 manufactured by Momentive: solid content 9 wt%, PGM 76 wt%, diacetone propanol 15 wt%), pulled up, and dried at 135 ° C. for 40 minutes to form a primer layer. bottom.
The substrate on which the prima layer was formed by the above steps is a silicone resin (AS4700F manufactured by Momentive) as a solute, propylene glycol monomethyl ether (PGM), n-butanol and acetic acid as a high boiling solvent, and methanol as a low boiling solvent. After dipping in a hard coat solution containing isopropyl alcohol (IPA) and water in the proportions shown in Table 1 below, the mixture was pulled up and dried at 140 ° C. for 60 minutes to form a hard coat layer and an intermediate layer. The production of the sample of Example 1 was completed.

[Example 2]
A translucent plate according to Example 2 having a primer layer and a hardcoat layer was obtained in the same manner as in Example 1 except that the composition of the hardcoat liquid was changed to the ratio shown in Table 1 below.

[Comparative Example 1]
A translucent plate according to Comparative Example 1 having a primer layer and a hardcoat layer was obtained in the same manner as in Example 1 except that the composition of the hardcoat liquid was changed to the ratio shown in Table 1 below.

<TEM observation>
The cross section of each sample was observed using a transmission electron microscope (JEM2010 manufactured by JEOL Ltd.). The acceleration voltage was 200 kV.

In the sample of Example 1, an intermediate layer 14 having a thickness of 0.55 μm was formed between the primer layer 12 having a thickness of 2.6 μm and the hard coat layer 13 having a thickness of 3.1 μm.
Further, in the sample of Example 2, an intermediate layer 14 having a thickness of 0.48 μm was formed between the primer layer 12 having a thickness of 2.8 μm and the hard coat layer 13 having a thickness of 6.0 μm. ..
On the other hand, as shown in FIG. 3, in the sample of Comparative Example 1, no intermediate layer was formed between the primer layer 12 having a thickness of 2.6 μm and the hard coat layer 13 having a thickness of 3.8 μm. ..

As shown in Table 1 above, in Examples 1 and 2, the content of water in the solvent is in the range of 10 to 30% by weight, and the total content of the low boiling point solvent is 25 to 50% by weight. %, Since the total content of the high boiling point solvent is in the range of 30 to 50% by weight, it is considered that a sufficient ratio of the high boiling point solvent remains in the process of evaporation of the hard coat liquid to form an intermediate layer.
On the other hand, in Comparative Example 1, the total amount of the high boiling point solvent was as low as 28.6% by weight, while the content of the low boiling point solvent was as high as 53.3% by weight, so that the hard coat liquid was in the process of evaporating. It is probable that the intermediate layer could not be formed because a sufficient proportion of the high boiling point solvent did not remain.

<Evaluation of durability>
The durability of each sample was evaluated by performing the boiling test shown below and evaluating the adhesion between the hard coat layer and the primer layer.

The hard coat layer of each sample was cross-cut in a grid pattern (100 squares of 1 mm ² ), and then immersed in ion-exchanged water at 100 ° C. for 2 hours under normal pressure. After that, a JIS Z 1522 compliant cellophane adhesive tape (manufactured by Nichiban Co., Ltd.) was attached on the hard coat layer, pressed strongly with a finger, then peeled off in the 90 ° direction, and evaluated by the number of peeled hard coat layers. gone.

The number of peeled samples of Examples 1 and 2 was 0, and the number of peeled samples of Comparative Example 1 was 14. From the comparison between Example 1 and Example 2 and Comparative Example 1, it is possible to improve the adhesion between the hard coat layer and the primer layer by forming an intermediate layer between the primer layer and the hard coat layer. confirmed.

1 Translucent plate 11 Base material 12 Primer layer 13 Hard coat layer 14 Intermediate layer

Claims (4)

A hardcoat liquid for forming a hardcoat layer that protects the surface of a resin made of a polyacrylic acid ester derivative.
The hardcourt liquid is composed of a silicone resin and a solvent component containing water and a protonic organic solvent.
The protonic organic solvent comprises a high boiling point solvent having a boiling point of more than 100 ° C. and a low boiling point solvent having a boiling point of less than 100 ° C.
The hard coat is characterized in that the content of the high boiling point solvent in the whole solvent component is 30 to 50% by weight, the content of the low boiling point solvent is 25 to 50% by weight, and the content of water is 10 to 30% by weight. liquid. The hardcoat liquid according to claim 1, wherein the protonic organic solvent is an alcohol or a carboxylic acid. The hardcoat liquid according to claim 1 or 2 , which contains ceramic particles. A method for producing a hardcoat layer, which comprises applying the hardcoat liquid according to any one of claims 1 to 3 to the surface of a resin made of a polyacrylic acid ester derivative and drying it.

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