KR102513783B1 - Double heat curing type hard coating composition, decorative sheet using the same, and the method for manufacturing the same - Google Patents

Abstract

According to the present specification, disclosed are a hard coating composition and a decorative film for in-mold injection using the composition as a hard coating layer, wherein the hard coating composition includes: 50-80 parts by weight of a thermosetting polyol resin; 10-30 parts by weight of a polyisocyanate-based thermosetting agent; and 10-20 parts by weight of a block-polyisocyanate-based heat curing agent.

Description

Double heat-curable hard coating composition, decorative sheet using the same, and manufacturing method thereof

The present disclosure relates to a decorative film for in-mold injection characterized by double heat curing.

The in-mold injection process is a plastic injection method for manufacturing industrial parts or daily necessities, and is a process in which a film is inserted during injection molding in the manufacturing process, and the injection product and the film are integrated to make a product. At this time, the film used as a finishing material on the outer surface of the product is called a decorative film for in-mold injection.

In general, decorative films for in-mold injection are formed by applying a coating layer to a film made of polyethylene terephthalate (PET), polycarbonate (PC), or polyacrylate (PA).

The decorative film for in-mold injection may have a multilayer structure including a hard coating layer and a printing layer, as well as a primer layer and an adhesive layer, if necessary. Deco film for in-mold injection requires high moldability due to the characteristics of the in-mold injection process and requires high durability such as scratch resistance due to the characteristics located on the outer surface of the finished product. For this reason, the outermost layer of the decorative film for in-mold injection forms a hard coating layer. In order to secure high scratch resistance, a hard coating layer having a high curing density is formed.

However, in the case of a hard coating agent having a high curing density, it is difficult to use it for products requiring high moldability due to cracks during molding.

On the other hand, when the curing density is lowered in order to secure moldability, there is a problem of poor scratch resistance. Therefore, in order to secure the formability and scratch resistance of such a decorative film for in-mold injection, various countermeasures have been proposed from the past.

Specifically, Patent Document 1 discloses a method for securing high scratch resistance while maintaining moldability by using a dual curable hard coating composition capable of UV and heat curing, but a separate UV irradiation process is required after manufacturing an injection product. In the case of injection molding products with various curved surface characteristics, it is not possible to provide a solution to the deviation of physical properties and the occurrence of curls that can occur depending on the UV irradiation area.

Patent Document 2 discloses a method of providing a hard coating composition capable of improving the wear resistance of a hard coating layer without increasing the content of hard particles in the composition using a hard coating composition using a polysiloxane-based compound, but the curing process A fundamental solution has not been proposed to improve formability and scratch resistance through improvement.

In Patent Document 3, the hard coating layer is a reaction product of an isocyanate compound obtained by reacting polyether polyol and aromatic diisocyanate with an acrylate monomer having a hydroxyl group, a bifunctional urethane acrylate oligomer, a multifunctional urethane acrylate oligomer, and a multifunctional epoxy acryl A method including a late oligomer has been disclosed, but a solution that simultaneously satisfies fundamental formability and scratch resistance has not been proposed.

Patent Document 4 discloses a method of implementing a highly weatherable hard coating composition by introducing a multifunctional acrylic monomer, but as a hard coating agent of a method of coating the surface after manufacturing an injection product, IMD method moldability and scratch resistance are simultaneously exhibited. No satisfactory solution is presented.

As described above, none of the previously disclosed methods have been able to provide a method for simultaneously and stably solving the problems of formability and scratch resistance of the film in the in-mold injection process.

KR 10-2017-0120754 A KR 10-2018-0006744 A 2008-260231 A KR 10-2020-0054670 A

Accordingly, the inventors of the present invention intend to provide a decorative film for in-mold injection that can stably solve the problems of moldability and scratch resistance of the film in the in-mold injection process.

Accordingly, by introducing a heat-curable hard coating composition having selective dual heat-curing characteristics with different curing temperatures, a heat-curable hard coating composition capable of securing high scratch resistance while maintaining excellent moldability through selective double-curing is applied. It is intended to secure such moldability and scratch resistance properties at the same time.

In one embodiment according to the present invention to achieve the above object, 50-80 parts by weight of a thermosetting polyol resin; 10-30 parts by weight of a polyisocyanate-based thermosetting agent; And 10-20 parts by weight of a block-polyisocyanate-based heat curing agent; provides a hard coating composition comprising a.

In one embodiment, the polyisocyanate-based thermosetting agent and the block-polyisocyanate-based thermosetting agent may have different curing temperatures.

In one embodiment, the block-polyisocyanate-based thermosetting agent may be a reaction product of polyisocyanate and a blocking agent.

In one embodiment, the blocking agent is Methylethylketone Oxime, Benzophenone Oxime, Thiophenol, Pentafluorothiophenol, Pirrolidinone, ε-Caprolactam, Imidazole, 2-Methylimidazole, 2-Phenylimidazole, Dimethylpyrazole, 2-Methyl-4-ethyl-5-methylpyrazol, Benzotriazole , and may include one or more selected from the group consisting of Triazole.

In one embodiment, it may include 60-80 parts by weight of a thermosetting polyol resin, 15-25 parts by weight of a polyisocyanate-based thermosetting agent, and 12-18 parts by weight of a block-polyisocyanate-based thermosetting agent.

In another embodiment according to the present invention, a hard coating layer comprising a cured product of the above-described hard coating composition; And a base film; a decorative film for in-mold injection comprising a is provided.

In one embodiment, the hard coating layer may have a thickness of 1 ~ 20㎛.

In another embodiment according to the present invention, a hard coating composition comprising 50-80 parts by weight of a thermosetting polyol resin, 10-30 parts by weight of a polyisocyanate-based thermosetting agent, and 10-20 parts by weight of a block-polyisocyanate-based thermosetting agent forming; Forming a hard coating layer by applying the hard coating composition on a base film; And heat-curing the hard coating composition; including, a decorative film manufacturing method for in-mold injection is provided.

In one embodiment, in the thermal curing step, a first thermal curing step and a second thermal curing step are sequentially performed, and the first thermal curing temperature may be lower than the second thermal curing temperature.

In one embodiment, the first thermal curing temperature may be in the range of 90 to 120 °C, and the second thermal curing temperature may be in the range of 130 to 160 °C.

In one embodiment, forming an injection product by molding the decor film for in-mold injection; may further include.

The hard coating composition according to an exemplary embodiment of the present invention and the decorative film for in-mold injection to which the same is applied can secure high scratch resistance while maintaining excellent moldability through dual curing by selectively simultaneously having post-thermal curing conditions. In addition, excellent gloss, surface hardness and solvent resistance can be secured. In addition, by introducing a heat curing process, it is possible to prevent curl of products that may occur in a conventional UV curing process.

1 shows a laminated structure of a decor film for in-mold injection according to an embodiment of the present invention.
Figure 2 shows a flow chart of a manufacturing process of a decorative film for in-mold injection according to an embodiment of the present invention.

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

The embodiments of the present invention disclosed in the text are illustrated for purposes of explanation only, and the embodiments of the present invention may be implemented in various forms and should not be construed as being limited to the embodiments described in the text. .

The present invention can have various changes and can have various forms, the embodiments are not intended to limit the present invention to a specific disclosed form, and all changes, equivalents or substitutes included in the spirit and technical scope of the present invention It will be understood to include.

Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "include" or "have" are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

hard coating composition

In an exemplary embodiment according to the present invention to achieve the above object, 50-80 parts by weight of a thermosetting polyol resin; 10-30 parts by weight of a polyisocyanate-based thermosetting agent; And 10-20 parts by weight of a block-polyisocyanate-based heat curing agent; provides a hard coating composition comprising a.

Hereinafter, FIG. 1 shows a laminated structure of a decor film for in-mold injection according to an embodiment of the present invention, and will be described with reference to this.

In an exemplary embodiment, a thermosetting polyol resin may be added for the purpose of improving moldability through chemical cross-linking by reacting with a polyisocyanate-based thermosetting agent containing an isocyanate group.

These thermosetting polyol resins can be classified into urethane-based and ester-based based on their structure, and can be applied differently depending on the characteristics of a target hard coating layer. For example, when adhesion is required, an ester-based polyol resin may be applied, and when elasticity is required, a urethane-based polyol resin may be applied. An ester-based polyol resin may be applied. In addition, generally preferably, two or more polyol resins may be mixed and applied in an appropriate mixing ratio.

Meanwhile, the heat curing agent may include at least one selected from isocyanate-based curing agents, melamine-based thermal curing agents, epoxy-based thermal curing agents, and the like, but is not limited thereto.

In an exemplary embodiment, the polyisocyanate-based thermosetting agent may have two or more isocyanate groups.

On the other hand, in an exemplary embodiment, the heat curing agent may be applied by combining two or more different types of heat curing agents, for example, a polyisocyanate-based thermal curing agent and a block-polyisocyanate-based thermal curing agent may be applied in combination. can In this case, the polyisocyanate-based thermosetting agent and the block-polyisocyanate-based thermosetting agent may have different curing temperatures.

When polyisocyanate or block-polyisocyanate is used alone, the curing reaction proceeds in one specific temperature range, but when polyisocyanate and block-polyisocyanate are used in combination as thermal curing agents, the curing reaction (first It is possible to form a semi-cured film by reacting only polylithocyanate to be cured), and through this, the deformation of the coating film can be freed, which can be advantageous in manufacturing molded products.

In this way, the molded film in the semi-cured state is subjected to a final curing reaction (second curing) at the curing temperature of the block-polyisocyanate, thereby realizing a hard coating film that is easy to mold. Therefore, as a hard coating layer for simultaneously having excellent formability and scratch resistance in the decorative film for in-mold injection according to an embodiment of the present invention, a film in a semi-cured state capable of processing such as molding in the middle can be implemented.

In an exemplary embodiment, a specific amount of polyisocyanate and block-polyisocyanate may be included as the thermosetting polyol resin and the thermosetting agent.

Specifically, the thermosetting polyol resin may be contained in 50-80 parts by weight, preferably 60-80 parts by weight. If the content of the thermosetting polyol resin is less than 50 parts by weight, chemical resistance may deteriorate due to the remaining reactor after curing, and if the content of the thermosetting polyol resin exceeds 80 parts by weight, chemical crosslinking is not sufficient. Therefore, the effect of improving surface hardness may be insignificant.

In addition, the polyisocyanate-based heat curing agent may be contained in 10-30 parts by weight, preferably 15-25 parts by weight. If the content of the polyisocyanate-based thermosetting agent is less than 10 parts by weight, heat curing may not be sufficiently achieved, and if the content of the polyisocyanate-based thermosetting agent exceeds 30 parts by weight, some unreacted polyisocyanates that do not react Isocyanates can cause surface defects.

In addition, the block-polyisocyanate-based heat curing agent may be contained in 10-20 parts by weight, preferably 12-18 parts by weight. If the content of the block-polyisocyanate-based thermosetting agent is less than 10 parts by weight, it may cause a problem in that thermal curing is not sufficiently achieved during secondary high-temperature thermal curing, and if the content of the block-polyisocyanate-based thermosetting agent exceeds 20 parts by weight, In some cases, blocked-polyisocyanate may cause surface defect problems due to the blocking agent discharged from the secondary high-temperature heat curing reaction.

In an exemplary embodiment, the block-polyisocyanate-based thermosetting agent is a material capable of undergoing a reaction at a specific temperature by transforming polyisocyanate, and the desired reaction temperature is set according to the type of blocking agent that transforms polyisocyanate. There are advantages to designing.

In an exemplary embodiment, the block-polyisocyanate-based thermosetting agent may be a reaction product of polyisocyanate and a blocking agent. Specifically, the blocking agent is Methylethylketone Oxime, Benzophenone Oxime, Thiophenol, Pentafluorothiophenol, Pirrolidinone, ε-Caprolactam, Imidazole, 2-Methylimidazole, 2-Phenylimidazole, Dimethylpyrazole, 2-Methyl-4-ethyl-5-methylpyrazol, Benzotriazole, Triazole It may include one or more selected from the group consisting of.

Decor film for in-mold injection

In another embodiment according to the present invention, the hard coating layer 10 comprising a cured product of the above-described hard coating composition; And a base film 20; including, the decorative film 100 for in-mold injection is provided.

On the other hand, the decor film for in-mold injection requires high moldability due to the characteristics of the in-mold injection process and requires high durability such as scratch resistance due to the characteristics located on the outer surface of the finished product. For this reason, in-mold injection The outermost layer of the decorative film may form a hard coating layer, and in order to secure high scratch resistance, a hard coating layer 10 having a high curing density may be formed.

In an exemplary embodiment, the hard coat layer 10 may have a thickness of 1 to 20 μm, preferably 5 to 10 μm. If the thickness of the hard coating layer 10 is less than 1 μm, it may be difficult to function as a hard coating due to the low surface hardness of the hard coating, and if it exceeds 20 μm, cracks (cracks) may occur outside the bent portion during molding. there is.

In an exemplary embodiment, the base film 20 may include polyethylene terephthalate (PET), polycarbonate (PC), or polyacrylate (PA), but is not limited thereto.

In an exemplary embodiment, the decorative film 100 for in-mold injection may have a multilayer structure further including at least one of a printing layer, a primer layer, and an adhesive layer.

Method for manufacturing decorative film for in-mold injection

Hereinafter, Figure 2 shows a flow chart of a manufacturing process of a decorative film for in-mold injection according to an embodiment of the present invention, and will be described with reference to this.

In another embodiment according to the present invention, a hard coating composition comprising 50-80 parts by weight of a thermosetting polyol resin, 10-30 parts by weight of a polyisocyanate-based thermosetting agent, and 10-20 parts by weight of a block-polyisocyanate-based thermosetting agent forming; Forming a hard coating layer 10 by applying the hard coating composition on a base film 20; And heat-curing the hard coating composition; including, a decorative film manufacturing method for in-mold injection is provided.

In an exemplary embodiment, a first thermal curing step and a second thermal curing step are sequentially performed in the thermal curing step, and the first thermal curing temperature may be lower than the second thermal curing temperature.

Specifically, through the low-temperature first thermal curing, a low-density reaction between the reactors of the thermosetting polyol resin and the polyisocyanate-based thermal curing agent proceeds to form an elastic structure so as to have moldability and elasticity.

In addition, through the second thermal curing at a high temperature, the thermosetting polyol resin and the block-polyisocyanate-based thermal curing agent can additionally react, and through this, high-density curing proceeds on the surface of the hard coating layer to secure high surface hardness. there is.

Therefore, in the decorative film for in-mold injection according to an embodiment of the present invention, a first thermal curing step and a second thermal curing step simultaneously having different thermal curing temperatures may be sequentially performed, and such dual thermal curing Through this, it is possible to secure high scratch resistance while maintaining excellent formability.

Specifically, the first thermal curing temperature may be in the range of 90 to 120 °C, and the second thermal curing temperature may be in the range of 130 to 160 °C. The first thermal curing step and the second thermal curing step are sequentially performed within the above temperature range to provide a decorative film for in-mold injection having excellent formability and scratch resistance at the same time.

In an exemplary embodiment, forming an injection product by molding the decor film for in-mold injection; may further include. Forming such an injection-molded product may be performed between the first thermal curing step and the second thermal curing step.

For example, the method for manufacturing a decorative film for in-mold injection according to an embodiment of the present invention includes (a) preparing a double heat-curable hard coating composition, (b) applying the double heat-curable hard coating composition on a base film After coating and drying, it is divided into steps of firstly curing by heat to form a hard coating layer 10, and as a method of manufacturing an injection product using the decor film 100 obtained in this way, (c) the hard coating layer It may include forming the film containing the film, (d) secondarily thermally curing the film containing the hard coating layer.

Example

Hereinafter, the present invention will be described in more detail through examples. These examples are only for illustrating the present invention, and it will be apparent to those skilled in the art that the scope of the present invention is not to be construed as being limited by these examples.

Example: Preparation of hard coating composition and decorative film for in-mold injection

1) As a thermosetting polyol resin, an ester-based polyol resin having a mass average molecular weight (Mw) of 2,500 and a solid content of 90%, and polyisocyanate is TDI (Toluene-2,4-diisocyanate) having a solid content of 30% and H having a solid content of 30% ₁₂ MDI (4,4'-dicyclohexil-methanediisocyanate) was mixed and used at a ratio of 1: 1, and as block-polyisocyanate, TDI blocked with MEK (Methylethylketone) Oxime was used at a solid content of 30%, as shown in Table 1 below. A hard coating composition was prepared by mixing in an amount.

Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Example 1 Example 2 Example 3 Thermosetting resin (parts by weight) 70 70 70 70 70 70 75 65 Polyisocyanate (parts by weight) 20 10 5 20 20 15 10 25 Block-polyisocyanate (parts by weight) 10 20 25 10 10 15 15 15 1st heat curing temperature (℃) 100 100 100 130 100 100 120 110 2nd heat curing temperature (℃) 130 130 130 130 140 130 130 140 Elongation at 130℃ high temperature before the second heat curing (%) 180 180 180 70 180 180 180 160 High temperature elongation at 130℃ after secondary heat curing (%) 60 60 130 80 50 60 70 55 Forming depth after 2nd heat curing (mm) 1.5 1.8 2.8 1.2 1.4 1.9 2.4 2.2 Pencil hardness after secondary heat curing B B 2B B HB HB HB F Surface whitening after 2nd heat curing non-occurrence generation generation non-occurrence non-occurrence non-occurrence non-occurrence non-occurrence

2) The prepared hard coating composition was applied on a polycarbonate film of Mitsubishi Gas Chemical Co. with a thickness of 250 μm by Micro Gravure coating method, and a decorative film for in-mold injection was prepared using a 26 # cell depth cylinder 26 μm.

At this time, the hard coating is a form of dissolving the resin in an organic solvent to form a solution, which is applied to a polycarbonate film in a wet state and then dried to have a thickness of 1 to 20 μm after drying.

Then, the first heat curing was performed under the conditions of Table 1, and then the decorative film was manufactured and molded as an injection product, and the second heat curing was performed under the conditions of Table 1.

Experimental Example: Characteristics of decorative film for in-mold injection

High temperature elongation was measured by the method of ASTM D638 under the condition of 130 °C. As for the molding depth, the maximum value of the depth at which cracks do not occur in the coating film was measured while press molding using a mold having an edge R = 2 in an area of 10 cm X 10 cm. Pencil hardness was measured by the method of ASTM D3363. Surface whitening after secondary thermal curing was measured by the method of ASTM D1003, and it was determined that surface whitening occurred when the transmittance value was 80% or less.

From the results, as can be seen in Table 1 above, it can be seen that a decorative film having excellent scratch resistance and formability at the same time that satisfies the conditions of the present invention can be manufactured.

The embodiments of the present invention described above should not be construed as limiting the technical spirit of the present invention. The protection scope of the present invention is limited only by the matters described in the claims, and those skilled in the art can improve and change the technical spirit of the present invention in various forms. Therefore, these improvements and modifications will fall within the protection scope of the present invention as long as they are obvious to those skilled in the art.

Claims (11)

50-80 parts by weight of a thermosetting polyol resin;
10-30 parts by weight of a polyisocyanate-based thermosetting agent; and
10-20 parts by weight of a block-polyisocyanate-based heat curing agent; comprising a hard coating composition.
According to claim 1,
The polyisocyanate-based heat curing agent and the block-polyisocyanate-based heat curing agent have different curing temperatures, hard coating composition.
According to claim 1,
The block-polyisocyanate-based heat curing agent is a reaction product of polyisocyanate and a blocking agent, hard coating composition.
According to claim 3,
The blocking agent is a group consisting of Methylethylketone Oxime, Benzophenone Oxime, Thiophenol, Pentafluorothiophenol, Pirrolidinone, ε-Caprolactam, Imidazole, 2-Methylimidazole, 2-Phenylimidazole, Dimethylpyrazole, 2-Methyl-4-ethyl-5-methylpyrazol, Benzotriazole, Triazole A hard coating composition comprising at least one selected from.
According to claim 1,
A hard coating composition comprising 60-80 parts by weight of a thermosetting polyol resin, 15-25 parts by weight of a polyisocyanate-based heat curing agent, and 12-18 parts by weight of a block-polyisocyanate-based heat curing agent.
A hard coating layer comprising a cured product of any one of claims 1 to 5; and
A decorative film for in-mold injection comprising a; base film.
According to claim 6,
The hard coating layer is a decorative film for in-mold injection having a thickness of 1 to 20 μm.
Forming a hard coating composition comprising 50-80 parts by weight of a thermosetting polyol resin, 10-30 parts by weight of a polyisocyanate-based thermosetting agent, and 10-20 parts by weight of a block-polyisocyanate-based thermosetting agent;
Forming a hard coating layer by applying the hard coating composition on a base film; and
Thermally curing the hard coating composition; containing, decorative film manufacturing method for in-mold injection.
According to claim 8,
In the thermal curing step, a first thermal curing step and a second thermal curing step are sequentially performed,
The first thermal curing temperature is lower than the second thermal curing temperature, a decorative film manufacturing method for in-mold injection.
According to claim 9,
The first thermal curing temperature is in the range of 90 to 120 ° C,
The second heat curing temperature is in the range of 130 to 160 ° C., a method for manufacturing a decorative film for in-mold injection.
According to claim 9,
Molding the decor film for in-mold injection to form an injection product; further comprising a decorative film manufacturing method for in-mold injection.

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