KR20100050673A - Optical polymer substrate - Google Patents

Abstract

PURPOSE: An optical polymer film and a polymer substrate having superior adhesive properties of a primer layer are provided to obtain the polymer substrate in which a primer layer is formed by coating water-dispersible coating solution on the optical polymer film. CONSTITUTION: A polymer substrate comprises an optical polymer film and a primer layer. The primer layer is formed by coating a water-dispersible coating solution. The water-dispersible coating solution comprises: 1~50 weight% of a resin which is a urethane resin, an acrylic resin, a polyester copolymer resin, or a heat reactive type water-soluble polyisocyanate resin; 1~30 weight% of water-dispersible poly-carbodiimide; and 0.1~10 weight% of silica particle or alumina-silica complex oxide particle.

Description

Polymer substrate {OPTICAL POLYMER SUBSTRATE}

The present invention relates to a polymer substrate, and more particularly, a primer layer formed by applying an aqueous dispersion coating solution containing polycarbodiimide as a crosslinking agent on an optical polymer substrate film, and having excellent durability and moisture resistance. It relates to a polymer substrate having a layer formed thereon.

Examples of general functional polymer substrates include polyester-based substrates such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polycarbonate (PC), which are excellent in dimensional stability, thickness uniformity, and optical transparency. In addition, the range of applications is very wide for various industrial materials.

In particular, the optical polyester-based substrate is a primer layer formed on the polymer substrate film, the copolymer layer polyester resin having excellent adhesion to the polyester-based substrate as a primer layer component is mainly used, in general, the polymer substrate The adhesiveness of a film and a primer layer is excellent. However, when post-processing such as a prism, a lens, an antireflection layer, or a hard coating on the optical polyester-based substrate, the adhesion between the primer layer and the processed surface is excellent while the adhesion between the polymer substrate film and the primer layer is lowered. A problem arises.

Therefore, in order to improve the adhesion of the primer layer, acrylic or urethane resin is mainly used as a component of the primer layer. A problem arises.

In order to overcome the above problems, a crosslinking agent may be applied to the primer layer to form a polymer network, thereby improving durability. However, a crosslinking agent such as a melamine-based or epoxy-based polymer that is generally used is insufficient to crosslink the polymer of the primer layer. .

In addition, in general, when forming a primer layer on a polyester-based substrate, due to the hydrophilic nature of the substrate, the binder resin is dispersed in water to perform a water-based coating, it is a reality that a lot of restrictions in selecting a crosslinking agent.

Accordingly, many studies have been conducted to develop a crosslinking agent that has excellent reactivity and simultaneously improves adhesion.

Accordingly, the present inventors have endeavored to solve the conventional problems, and as a result, to improve the adhesiveness with the optical polymer substrate film, a polymer substrate composed of a primer layer formed by applying polycarbodiimide as a crosslinking agent to an acrylic or urethane resin The present invention was completed by confirming that the moisture resistance was improved under the harsh conditions of the durability and high temperature and high humidity of the primer layer, and thus excellent adhesion to the optical polymer substrate film during post-processing.

An object of the present invention is to provide a polymer substrate on which a primer layer is formed by applying an aqueous dispersion coating solution containing polycarbodiimide as a crosslinking agent on an optical polymer substrate film.

Another object of the present invention is to provide a polymer substrate having excellent adhesion between the optical polymer substrate film and the primer layer even during post-processing or under high temperature and high humidity conditions.

In order to achieve the above object, the present invention is any one selected from the group consisting of a urethane resin, an acrylic resin, a polyester copolymer resin and a thermally reactive water-soluble polyisocyanate resin on at least one surface of the optical polymer substrate film and the substrate film A polymer substrate comprising a primer layer formed by applying an aqueous dispersion coating solution comprising 1 to 50% by weight of the resin, 1 to 30% by weight of dispersed polycarbodiimide, and 0.1 to 10% by weight of silica particles or alumina-silica composite oxide particles. To provide.

The water dispersion coating liquid may further contain a tin-based catalyst, the content of which is preferably 0.1 to 10% by weight.

The average particle diameter of the said silica particle or alumina-silica composite oxide particle is 20-300 nm.

At this time, the surface tension of the polymer substrate is 30 ~ 60kg / m, the adhesive force between the optical polymer substrate film and the primer layer is calculated by the following equation 1, it is 100% under the conditions of high temperature and high humidity.

Equation 1

Adhesiveness (%) = (1- Peeled Area / Evaluation Area) × 100

The present invention forms a primer layer by applying an aqueous dispersion coating solution containing polycarbodiimide as a crosslinking agent on an optical polymer substrate film, thereby forming a carboxylic acid of acrylic, urethane, and polyisocyanate resins used in the primer layer. As the amide is easily bonded to build a strong network, durability is improved, and it is effective in preventing scratches. It is not only excellent in adhesion to other substrates during post processing, but also excellent in adhesion between the optical polymer base film and the primer layer, The polymer base material which improved the moisture resistance, was excellent in the adhesive force even under the conditions of high temperature, high humidity, and showed the optical characteristic of the haze 0.4-1.5% was provided.

Hereinafter, the present invention will be described in more detail.

1 to 50% by weight of at least one resin selected from the group consisting of an urethane resin, an acrylic resin, a polyester copolymer resin and a thermally reactive water-soluble polyisocyanate resin on at least one surface of the optical polymer substrate film and the substrate film It provides a polymeric substrate consisting of a primer layer formed by applying a water dispersion coating liquid consisting of 1 to 30% by weight of water-dispersed polycarbodiimide and 0.1 to 10% by weight of silica particles or alumina-silica composite oxide particles.

In the present invention, the primer layer is formed on one side or both sides of the optical polymer substrate film, and exhibits excellent adhesion and easy adhesion to facilitate adhesion with other substrates.

Optical polymer substrate film used in the present invention is a high functional polymer substrate excellent in dimensional stability, thickness uniformity and optical transparency, the use thereof is not particularly limited, polyethylene terephthalate (PET), polyethylene taphthalate (PEN) and Preference is given to the use of polyester-based substrates such as polycarbonate (PC).

The polycarbodiimide applied as a crosslinking agent in the aqueous dispersion coating solution has good reactivity with the polyester-based substrate and helps adhesion between the polyester-based substrate and the primer layer. In addition, by easily bonding with the carboxylic acid and amide of urethane resin, acrylic resin and polyisocyanate resin, which are widely used as primer layers in the industry, it is possible to form a strong network (crosslinking) to improve the durability of the primer layer, It is preferable to apply in the form of a crosslinking agent or a curing agent in which carbodiimide is bonded to a polymer functional group in order to improve dispersibility and reactivity for waterborne coating.

More specifically, the water dispersion coating liquid is a urethane resin, acrylic resin, polyester copolymer resin and heat-reactive water-soluble polyisocyanate resin is contained 1 to 50% by weight, if the content is less than 1% by weight of the primer layer Is not preferable because it is too thin, the content is more than 50% by weight is not preferable because there is a problem that a large amount of coating unevenness occurs because the coating is uneven due to high viscosity when coated on the polyester-based substrate.

The water-dispersed polycarbodiimide contains 1 to 30% by weight, if the content is less than 1% by weight, the content thereof is not sufficient, and the adhesion between the resin network (crosslinking) of the primer layer and the polymer base film for optics is insufficient. According to the present invention, durability and moisture resistance may be lowered, and thus, the object of the present invention may not be achieved, and when the content exceeds 30% by weight, it is difficult to store the polymer substrates when applied to both sides because of the reactivity of the polycarbodiimide, which can be reacted at room temperature. And carbodiimide functional groups are present in an unreacted state, and thus are poor in moisture resistance.

In addition, the aqueous dispersion coating liquid may further be used as an additive to the organic particles, inorganic particles and antifoaming agent to facilitate the heat-resistant processing on the coating and primer layer on the optical polymer substrate film. In this case, in the case of the inorganic particles, silica particles or alumina-silica composite oxide particles are preferably used. The use of the inorganic particles is advantageous in that the production rate can be secured by increasing the running performance when the inorganic resin particles containing the constituent resin and the refractive index difference of the aqueous dispersion coating are relatively small, wherein the average particle diameter of the inorganic particles is 20 to 500 nm, more preferably 50 It is -300 nm. If the average particle diameter of the inorganic particles is less than 20 nm, when the automated system is applied, the fine particles are lower than the primer layer thickness on the substrate, which does not help runability and scratch resistance, and the effect of the fine particles is not expected. If the particle diameter exceeds 500 nm, the haze is poor and not preferable.

In this case, the silica particles or alumina-silica composite oxide particles contain 0.1 to 10% by weight, the content of the particles is less than 0.1% by weight does not significantly help the runability, if the content exceeds 10% by weight turbidity of the product It is not desirable because it increases and the film becomes opaque.

Furthermore, in the case of using the heat-reactive water-soluble polyisocyanate resin in the resin, it is possible to further use a 0.1 to 10% by weight tin-based catalyst to make the monoisocyanate into a polyisocyanate, and the catalyst increases the reaction of the terminal functional group. It works well for polymerization.

In addition, the aqueous dispersion coating liquid may further contain a surfactant dispersed for the aqueous coating, and in order to increase the wettability of the optical polymer base film and to uniformly apply the aqueous dispersion coating liquid, a known anionic or nonionic surfactant is used. It can be applied onto a substrate.

The thickness of the primer layer formed by applying the aqueous dispersion coating solution on the optical polymer substrate film is preferably 0.05 to 3 μm. When the thickness of the primer layer is less than 0.05 μm, the transparency is good but the adhesive strength is poor during post-processing. When the thickness exceeds 3 μm, adhesive properties are excellent, but transparency and coating properties are deteriorated, which is not preferable.

The adhesive force of the polymer substrate is calculated by Equation 1 below, and the optical polymer substrate film even after 96 hours of high temperature and high humidity treatment at 60 to 70 ° C. and 90 to 99% humidity, more preferably at 65 ° C. and 95% humidity. And 100% of the adhesion of the primer layer is excellent in moisture resistance.

Adhesiveness (%) = (1- Peeled Area / Evaluation Area) × 100

Furthermore, the polymer cabin exhibits excellent optical properties with a total light transmittance of 90% or more and a haze of 0.4 to 1.5%.

That is, the present invention forms a primer layer by applying an aqueous dispersion coating solution containing polycarbodiimide as a crosslinking agent on the optical polymer substrate film, thereby forming a carboxylic acid and an acrylic, urethane, and polyisocyanate resin used in the primer layer. Amides are easily combined to increase durability. Therefore, the polymer base material of the present invention is not only the adhesion between the primer layer and other base materials, but also the post-processing of the prism lens processing, the hard coat and the AR processing, etc., on the primer layer, Provided is a polymer substrate having excellent adhesive strength, excellent adhesion with a base film even under conditions of high temperature and high humidity, and exhibiting excellent optical properties with a haze of 0.4 to 1.5%.

Hereinafter, the present invention will be described in detail with reference to examples.

The following examples are merely illustrative of the present invention, but the scope of the present invention is not limited to the following examples.

≪ Example 1 >

10% by weight of water-soluble polyisocyanate resin dispersion containing 23% by weight of isocyanate molecules, 5% by weight of polycarbodiimide aqueous solution containing 30% by weight of carbodiimide molecules, and 10% by weight of tin catalyst 0.5 wt% tin-based catalyst aqueous dispersion, 1 wt% anionic surfactant dispersion containing 10 wt% anionic surfactant, and 0.1 wt% colloidal silica particle aqueous dispersion containing 70 wt% colloidal silica particles To prepare a dispersion coating solution by mixing. The aqueous dispersion coating solution was applied to a polyester film having a thickness of 188 μm to obtain a polymer substrate having a primer layer. At this time, the surface tension of the polymer substrate is 30kg / m.

<Example 2>

Anionic surfactant containing 10 wt% of acrylic resin aqueous dispersion containing 20 wt% of acrylic resin, 5 wt% of polycarbodiimide aqueous dispersion containing 30 wt% of carbodiimide molecule, and 10 wt% of anionic surfactant An aqueous dispersion coating solution was prepared by mixing 1.0 wt% of an aqueous dispersion and 0.1 wt% of an aqueous dispersion of colloidal silica particles containing 70 wt% of colloidal silica particles. The aqueous dispersion coating solution was applied to a polyester film having a thickness of 188 μm to obtain a polymer substrate having a primer layer. At this time, the surface tension of the polymer substrate is 35kg / m.

<Example 3>

The urethane resin is an anionic interface containing 10% by weight of an aqueous dispersion of urethane resin containing 20% by weight, 5% by weight of an aqueous dispersion of polycarbodiimide containing 30% by weight of carbodiimide molecules, and 10% by weight of anionic surfactant. An aqueous dispersion coating solution was prepared by mixing 1.0 wt% of the active agent aqueous dispersion and 0.1 wt% of the colloidal silica particle aqueous dispersion containing 70 wt% of the colloidal silica particles. The aqueous dispersion coating solution was applied to a polyester film having a thickness of 188 μm to obtain a polymer substrate having a primer layer. At this time, the surface tension of the polymer substrate is 43kg / m.

<Example 4>

A polymer substrate was obtained in the same manner as in Example 1, except that 10 wt% of a polycarbodiimide aqueous dispersion was used.

Comparative Example 1

10% by weight of a water-soluble polyisocyanate resin dispersion containing 23% by weight of isocyanate molecules, 0.5% by weight of a catalyst catalyst containing 10% by weight of a tin catalyst, and 10% by weight of anionic surfactant. A polyester film was obtained in the same manner as in Example 1, except that 1.0% by weight of the dispersion and 0.1% by weight of the aqueous dispersion containing 70% by weight of the colloidal silica particles were prepared. At this time, the surface tension of the polyester film is 23kg / m.

Comparative Example 2

10% by weight of aqueous dispersion of thermally reactive water-soluble polyisocyanate resin containing 23% by weight of isocyanate molecules, 35% by weight of aqueous solution of polycarbodiimide (in excess) containing 30% by weight of carbodiimide molecules, 10% by weight of tin catalyst A water dispersion coating solution was prepared by mixing 0.5% by weight of an aqueous dispersion containing%, 1.0% by weight of an aqueous surfactant containing 10% by weight of anionic surfactant, and 0.1% by weight of an aqueous dispersion containing 70% by weight of colloidal silica particles. A polyester film was obtained in the same manner as in Example 1 except that one was obtained. At this time, the surface tension of the polyester film has a 48kg / m.

Comparative Example 3

10% by weight aqueous dispersion of water-soluble urethane resin containing 20% by weight of urethane molecule, 35% by weight of aqueous solution of polycarbodiimide (excess) containing 30% by weight of carbodiimide molecule, and 10% by weight of anionic surfactant A polyester film was obtained in the same manner as in Example 1, except that 1.0 wt% of the prepared aqueous dispersion and 0.1 wt% of the aqueous dispersion containing 70 wt% of the colloidal silica particles were prepared. . At this time, the surface tension of the polyester film has 56kg / m.

<Comparative Example 4>

A polyester film was obtained in the same manner as in Example 1, except that melamine was used as the crosslinking agent.

Comparative Example 5

A polyester film was obtained in the same manner as in Example 1, except that oxazoline was used as the crosslinking agent.

Experimental Example

The physical properties of the polyester film for optics prepared in Examples 1 to 4 and Comparative Examples 1 to 5 were measured and described in Table 2 below.

1. Initial Adhesion Measurement

An acrylic UV curable resin is applied to the surface on which the primer layer is formed using a wire bar, and a cutting line is made on the substrate coated with the primer layer by a cutter, and 2 mm × 2 mm squares are placed on a 10 × 10 matrix. A cellophane tape (No. 405, made by NICHIBAN; width: 24 mm) was attached to the film with the cut line, and the tape was rubbed with a tape to strongly adhere to the film, and then the tape was peeled off vertically. The area of the primer layer remaining as the adhesive layer was visually observed, and the adhesive force was calculated by the following equation.

Equation 1

Adhesiveness (%) = (1- Peeled Area / Evaluation Area) × 100

2. Measurement of adhesion after high temperature and high humidity

Apply the acrylic UV curable resin to the surface where the primer layer is formed using a wire bar, and leave it for 96 hours at 65 ° C. and 90% humidity, and then make a cutting line on the substrate coated with the primer layer using a cutter. Place 2 mm x 2 mm squares in the matrix. A cellophane tape (No. 405, made by NICHIBAN; width: 24 mm) was attached to the film with the cut line, and the tape was rubbed with a tape to strongly adhere to the film, and then the tape was peeled vertically to remove the adhesive layer on the substrate. As a result, the area of the remaining primer layer was visually observed, and the adhesion was calculated by the above equation.

Item Substrate Thickness (㎛) Coating liquid Crosslinking agent Substrate Adhesiveness (%) Adhesiveness after high temperature and humidity (%) Surface tension (kg / m) Example 1 188 Polyisocyanate 5% by weight carbodiimide 100 100 30 Example 2 188 acryl 5% by weight carbodiimide 100 100 35 Example 3 188 urethane 5% by weight carbodiimide 100 100 43 Example 4 188 Polyisocyanate 10% by weight carbodiimide 100 100 45 Comparative Example 1 188 Polyisocyanate Carbodiimide 0% by weight 70 40 23 Comparative Example 2 188 Polyisocyanate Carbodiimide 35% by weight 100 70 48 Comparative Example 3 188 urethane Carbodiimide 35% by weight 100 80 56 Comparative Example 4 188 Polyisocyanate Melamine series 5% by weight 65 30 31 Comparative Example 5 188 Polyisocyanate 5% by weight of oxazoline 50 30 33

As shown in Table 1, in the case of the polymer substrates of Examples 1 to 4 containing the carbodiimide as a crosslinking agent, the adhesive layer between the optical polymer substrate film and the primer layer even after post-processing was performed on the primer layer. This is excellent at 100%. In addition, it can be seen that the moisture resistance is excellent as the adhesive strength with the base film exhibits 100% even under the conditions of high temperature and high humidity, as well as excellent optical properties as the haze value is 0.3 ~ 1.0 or less.

On the other hand, in Comparative Example 1 in which no carbodiimide was used, the adhesion was very poor at 40% under the conditions of high temperature and high humidity, and in the case of Comparative Example 2 in which excess carbodiimide was used, the initial adhesion was rather. Both adhesive and high temperature and high humidity conditions are insufficient.

The polymer substrate of the present invention is coated with an aqueous dispersion coating solution containing polycarbodiimide as a crosslinking agent on an optical polymer substrate film to form a primer layer, thereby forming a carbohydrate of acrylic, urethane and polyisocyanate resins used in the primer layer. As the acid and amide are easily combined to build a strong network, even if the post-processing such as prism lens processing, hard coating, and AR processing is performed on the primer layer, not only the adhesiveness with other substrates, but also the optical polymer substrate film and Excellent adhesion between the primer layers, excellent adhesion to the polymer base film even under conditions of high temperature and high humidity, excellent moisture resistance, and exhibits optical properties of haze 0.4 to 1.5%, and can be used throughout various optical members. Base film, especially for display optical sheets, hard coat processing or AR films CRT is useful in the application of a protective film.

 Although the present invention has been described in detail only with respect to the embodiments described, it will be apparent to those skilled in the art that various modifications and variations are possible within the technical scope of the present invention, and such modifications and modifications belong to the appended claims.

Claims (5)

Optical polymer base film; And 1 to 50% by weight of at least one resin selected from the group consisting of a urethane resin, an acrylic resin, a polyester copolymer resin and a heat-reactive water-soluble polyisocyanate resin on at least one surface of the base film, water-dispersed polycarbodiimide 1 A primer layer formed by applying an aqueous dispersion coating liquid consisting of -30 wt% and 0.1-10 wt% of silica particles or alumina-silica composite oxide particles; Polymer substrate, characterized in that consisting of. The polymer base material according to claim 1, wherein the water dispersion coating solution contains 0.1 to 10% by weight of a tin catalyst. The polymer base material according to claim 1, wherein an average particle diameter of the silica particles or alumina-silica composite oxide particles is 20 to 300 nm. The polymer substrate according to claim 1, wherein the surface tension of the polymer substrate is 30 to 60 kg / m. The method of claim 1, wherein the adhesive force between the optical polymer substrate film and the primer layer is calculated by Equation 1 below, characterized in that the polymer substrate, characterized in that 100% under conditions of high temperature and high humidity. Equation 1 Adhesiveness (%) = (1- Peeled Area / Evaluation Area) × 100