KR101744950B1 - Method for manufacturing natural cork film - Google Patents

Abstract

The present invention relates to a method for producing a natural cork film which can prevent discoloration caused by oxidation of a cork through a step of discoloring a cork layer using a decoloring agent.

Description

METHOD FOR MANUFACTURING NATURAL CORK FILM BACKGROUND OF THE INVENTION [0001]

The present invention relates to a method for producing a natural cork film, and more particularly, to a method for producing a natural cork film which can prevent discoloration due to oxidation of cork.

Recently, as interest in the environment has increased, interest in environmentally friendly materials and eco-friendly materials has increased in interior parts used in automobiles and home appliances. This trend is also evident in the surface treatment of automotive interior materials.

Conventional methods for surface treatment of automobile interior materials include paint painting, metal plating, water pressure transfer, film insert molding, and natural material molding. This surface treatment method is applied to automobile interior trim, door trim, panel garnish, switch cover and so on.

Among these surface treatment methods, paint painting, metal plating, water pressure transfer, etc. cause environmental pollution in the manufacturing process and organic compounds are continuously generated due to the materials and the method used in the final product, Organic Compounds, Volatile Organic Compounds) regulations.

On the other hand, the production process of expensive natural materials which can give a sense of aesthetics and a sense of quality is very complicated, and the price is also higher than other synthetic materials, and thus it is applied only to some advanced vehicles.

Various natural materials that can be applied to a film insert molding method which can give an eco-friendly, aesthetic feeling and high quality due to various reasons have been studied. However, due to low tensile strength and bending strength inherent in natural materials, The phenomenon was constantly occurring and it was difficult to apply.

In order to solve such a problem, studies have been made on the use of a natural cork having excellent elasticity and flexibility as a film, such as Patent Registration No. 10-1274750, Registration No. 10-1274752 and Japanese Patent Application Laid-Open No. 10-2015-0072553 Has continued to progress.

However, as shown in FIG. 1, since the cork contains a lignin that causes discoloration during oxidation as a component inherent in natural wood, the natural cork film has a problem in that surface discoloration generally occurs after a lapse of a predetermined time I have.

Patent Registration No. 10-1274750 Patent Registration No. 10-1274752 Japanese Patent Application Laid-Open No. 10-2015-0072553

Disclosure of the Invention The present invention has been conceived to solve the problems as described above, and it is an object of the present invention to prevent the discoloration of the cork film due to oxidation of lignin by performing a step of pretreating the cork layer in order to prevent discoloration during the production process of the natural cork film. The present invention also provides a method for producing a natural cork film.

In order to solve the above-mentioned problems, a method of manufacturing a natural cork film according to the present invention includes the steps of: forming a cork layer of a thin film by processing natural cork into a plate form; , Attaching fibers to one side of the decolorized cork layer to form a fiber layer, and attaching a resin sheet to the fiber layer to form a resin layer.

In addition, the step of performing the pretreatment may include a step of decolorizing the cork layer using a decoloring agent.

Further, the decoloring agent is a mixture containing ammonia and hydrogen peroxide.

Further, the ammonia and the hydrogen peroxide are mixed in a weight ratio of 1: 9 to 9: 1.

In addition, the step of performing the pretreatment may further include washing the decolorized cork layer, and drying the washed cork layer at a temperature of 20 to 50 ° C.

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In addition, the step of forming the cork layer of the thin film may include peeling the cork material collected from the natural cork wood in the longitudinal direction or the transverse direction.

Further, the step of forming the cork layer of the thin film includes the steps of forming a cork chip by crushing the cork material collected from the natural cork wood, and pressing and mixing the cork chip and the binder .

The method may further include sanding the other surface of the decolorized cork layer.

The resin layer may be formed by attaching the resin sheet using an adhesive or by attaching the resin sheet to one surface of the cork layer by a thermocompression bonding method.

Further, the method may further include the step of attaching a transparent resin to the other surface of the decolorized cork layer by an adhesive or thermo compression bonding, or coating a transparent paint to form a coating layer.

The method of manufacturing a natural cork film according to the present invention has a effect of effectively preventing discoloration of a cork film by performing a step of pretreating a cork layer in order to prevent discoloration in a manufacturing process of a natural cork film .

Fig. 1 is a view for explaining a natural cork film in a discolored state.
2 is a flowchart illustrating a method of manufacturing a natural cork film according to the present invention.
FIG. 3 is a flowchart illustrating the process of performing the process of pre-processing the cork layer shown in FIG.
4 is a cross-sectional view of a cork film produced by the method of manufacturing a natural cork film according to the present invention.
5 is a comparative diagram for explaining the effect of preventing the discoloration of the natural cork film produced according to the present invention.

Hereinafter, a method of manufacturing a natural cork film according to the present invention will be described in detail with reference to the accompanying drawings.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood that the present invention is not intended to be limited to the specific embodiments but includes all changes, equivalents, and alternatives falling within the spirit and scope of the present invention.

In describing the present invention, the terms first, second, etc. may be used to describe various components, but the components may not be limited by the terms. The terms are only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

The term " and / or " may include any combination of a plurality of related listed items or any of a plurality of related listed items.

When an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, but other elements may be present in between Can be understood. On the other hand, when it is mentioned that an element is "directly connected" or "directly connected" to another element, it can be understood that no other element exists in between.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions may include plural expressions unless the context clearly dictates otherwise.

In the present application, the terms "comprises", "having", and the like are used interchangeably to designate one or more of the features, numbers, steps, operations, elements, components, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, parts, or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, may have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries can be interpreted as having a meaning consistent with the meaning in the context of the relevant art and are, unless expressly defined in the present application, interpreted in an ideal or overly formal sense .

In addition, the following embodiments are provided to explain more fully to the average person skilled in the art. The shapes and sizes of the elements in the drawings and the like can be exaggerated for clarity.

FIG. 2 is a flowchart for explaining a method of manufacturing a natural cork film according to the present invention, and FIG. 3 is a flowchart illustrating a step S20 of performing a pre-processing process of the cork layer shown in FIG.

Referring to FIG. 1, a method of manufacturing a natural cork film according to the present invention includes steps (S10) of forming a cork layer of a thin film by processing natural cork into a plate shape, A step (S30) of attaching fibers to one side of the cork layer of the thin film having been subjected to the pre-processing step (S30); and a step And forming a resin layer by attaching a sheet (S40).

Step S10 of forming a cork layer of a thin film is a process of thinning a cork material taken from natural cork wood.

The cork applied to the present invention is a natural tissue, which is a protective tissue made at the periphery of a stem or root of a plant that undergoes hypertrophic growth. Since the cork is formed by cleavage of the cork-forming layer, the cork exhibits regular cell arrangement, Electrical insulation, elasticity and so on.

The cork having such excellent properties can be thinned by stripping the cork material taken from the natural cork wood in the longitudinal direction or the transverse direction.

Alternatively, the cork material obtained from the natural cork wood may be pulverized to form a cork chip, and the cork layer may be formed by mixing and pressing the cork chip and the binder.

At this time, the thickness of the formed cork layer is suitably in the range of 0.05 to 5 mm. When the thickness of the peeled cork is less than 0.05 mm, the physical properties are largely deteriorated and the wear resistance is not exhibited. If the thickness of the peeled cork is 5 mm or more, the adhered product becomes thick, and the formability of the product during molding of the car interior material using the cork film is lowered.

Meanwhile, the cork layer of the thin film thinned through the above process is subjected to a step of performing a pretreatment step S20 to prevent discoloration.

That is, as described above, in the method of manufacturing a natural cork film according to the present invention, a pretreatment process is performed to prevent discoloration of the cork film due to lignin oxidation.

More specifically, as shown in FIG. 3, the pretreatment process for preventing discoloration includes a step S21 of decolorizing the cork layer using a decoloring agent.

That is, the method of manufacturing the natural cork film according to the present invention can prevent the cork film from being discolored after the cork film is artificially decolorized using the decolorant during the manufacturing process of the cork film.

The decolorant used in the decolorization step (S21) is not limited to the present invention as long as it can decolorize the cork film in an intended color. However, considering the productivity and manufacturing cost of the cork film, a mixture containing ammonia and hydrogen peroxide desirable.

At this time, it is preferable that ammonia and hydrogen peroxide are mixed in a weight ratio of 1: 9 to 9: 1.

On the other hand, as shown in FIG. 3, the cork layer of the thin film decolorized through the decolorant is washed with the decolorized cork layer, and the step of drying the washed cork layer at a temperature of 20 to 50 ° C S22) is performed.

The washing step is a step for removing the decolorizing agent impregnated into the cork layer. The decoloring agent may be immersed in the water in a certain container for a certain time to immerse the decolorized cork layer through the decoloring agent for about one to two times.

On the other hand, in order to neutralize the decolorant additionally, a certain neutralizing agent may be applied to the cork layer which can neutralize the decolorant during the washing step of the cork layer or before the washing step.

The drying step is a process of removing moisture contained in the cork layer so that the subsequent step can be performed on the cork layer that has been cleaned.

To prevent breakage of the cork layer and to save manufacturing time, the drying temperature may be limited to a specific temperature range, preferably 20 to 50 ° C.

Meanwhile, although not shown, a process of coloring the discolored cork layer with natural cork color or an intended color may be additionally performed.

Next, a fiber layer is formed by attaching fibers to one side of the cork layer of the thin film that has undergone the pretreatment process to prevent discoloration (S30).

The fibrous layer is a means for imparting a uniform strength to the cork layer. The material and shape of the fibrous layer according to the present invention are not limited, but preferably nylon, acrylic, cotton, polyurethane or the like may be used.

Such a fibrous layer may be attached to one surface (lower surface in Fig. 4) of the cork layer through an adhesive or through a thermocompression bonding method. Fig. 4 shows a structure in which a fibrous layer is bonded to the lower side of a cork layer through an adhesive by way of example, and a layered structure of an adhesive layer (first adhesive layer 12) is formed between the fibrous layer and the cork layer.

After the fiber layer forming step S30, as shown in FIG. 3, a polishing step S60 is performed to facilitate texture treatment of the surface of the cork layer and adhesion of a coating layer described later. The polishing step S60 may be any means well known in the art, such as sanding.

After the fibrous layer is attached to the cork layer and the texturing treatment on the surface of the cork layer is completed, a resin sheet is attached to the fibrous layer to form a resin layer (S40).

The resin sheet of the present invention is preferably ABS (Acrylonitrile Butadiene Styrene) resin, but is not limited thereto, and thermoplastic resins such as polypropylene, polyethylene, polyacetal resin, nylon resin, styrene resin and polycarbonate resin are applicable. Thermosetting resins such as epoxy resins, melamine resins, and polyurethane resins can also be used without limitation.

At this time, the thickness of the resin sheet is suitably 0.1 to 5 mm. When the thickness of the resin sheet is less than 0.1 mm, the bending strength and hardness are very weak and it is difficult to shape the product. If the thickness of the resin sheet is more than 5 mm, the bonded product thickens, This is because the moldability of the product is deteriorated.

The resin sheet can be attached to one side (lower side in Fig. 4) of the fiber layer through an adhesive or through a thermocompression bonding method, similar to the adhesion of the above-mentioned fiber layer.

After the step of forming the resin layer (S40) through the ordinary sheet, a step (S50) of forming a coating layer for preventing the contamination of the cork layer exposed to the outside and improving the surface properties proceeds.

The coating layer forming step (S50) is performed in such a manner that a transparent resin is adhered to the other surface of the cork layer by an adhesive agent, a thermo-compression bonding method, or a transparent paint is applied.

The coating layer may be formed by adhering a thin film transparent resin made of a thermoplastic or thermosetting resin such as a polycarbonate resin, a polyurethane resin, an epoxy resin, an ABS resin, a polypropylene resin, a polyethylene or a polyacetal resin with an adhesive, And may also be formed in such a manner that a liquid resin having the same material is applied and cured to the surface of the cork layer.

Fig. 4 is a cross-sectional view of a layer of a natural cork film formed through the above steps, in particular an embodiment in which each layer is attached via an adhesive.

The fibrous layer 13 is formed on the lower surface of the cork layer 11 and the first adhesive layer 12 is formed in a layered structure between the cork layer 11 and the fibrous layer 13, A resin layer 15 is formed on the lower side of the resin layer 13 and a second adhesive layer 14 is formed between the fiber layer 13 and the resin layer 15 in a layered structure.

A coating layer 16 is formed on the other side of the cork layer 11 and a third adhesive layer 17 is formed between the cork layer 11 and the coating layer 16 in a layered structure.

The natural cork film having such a structure can be molded into a product such as a vehicle interior material through a method known in the art, for example, an insert molding method.

As described above, the production method of the natural cork film according to the present invention has the effect of preventing discoloration of the natural cork film.

To confirm this, a comparative experiment was conducted under the following conditions.

First, as an example (A), a process of pretreating a thin film natural cork having a thickness of 0.3 mm and a coloring step were carried out, and then an adhesive film was attached to a nonwoven fabric of 0.1 mm, And made of natural cork film using 0.3mm thick ABS resin and 0.1mm thick adhesive film. The coloring step used a dye close to natural cork color so as to exhibit a color similar to that of the comparative example described later.

Here, the decoloring agent was a mixture in which ammonia and hydrogen peroxide were mixed at a weight ratio of 5: 5.

As a comparative example, a natural cork film was prepared by the same process as that of Example except that the pretreatment process and the coloring process were omitted.

Comparative Experiment There was no difference in the color of the outer surfaces of the Examples and Comparative Examples.

In order to confirm discoloration, the examples and comparative examples were similarly exposed to air at room temperature.

After a certain period of time elapsed from the start of exposure in the air at room temperature, as shown in the lower part of FIG. 5, in the comparative example, the color of the surface of the cork film gradually became darker and discoloration was started. It was confirmed that the color of the surface of the cork film of the example hardly changed even after the discoloration of the comparative example sufficiently progressed.

As described above, it is to be understood that the technical structure of the present invention can be embodied in other specific forms without departing from the spirit and essential characteristics of the present invention.

It should be understood, therefore, that the embodiments described above are to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than the foregoing description, And all changes or modifications derived from equivalents thereof should be construed as being included within the scope of the present invention.

Claims (10)

Processing the natural cork to a plate shape to form a thin cork layer;
Treating the cork layer of the thin film to prevent discoloration;
Forming a fibrous layer by attaching fibers to one side of the cork layer of the thin film having undergone the pre-processing step; And
Attaching a resin sheet to the fibrous layer to form a resin layer;
Lt; / RTI >
The pre-processing may include:
Decolorizing the cork layer of the thin film using a decolorant;
Washing the cork layer of the decolorized thin film; And
Drying the cork layer of the washed thin film in a temperature environment of 20 to 50 ° C;
Lt; / RTI >
Further comprising the step of sanding the other surface of the cork layer of the thin film after the step of forming the fibrous layer,
Further comprising the step of attaching a transparent resin to the other surface of the cork layer of the thin film after the sanding treatment of the other surface of the cork layer of the thin film by an adhesive or thermo compression bonding or by coating a transparent paint to form a coating layer ≪ / RTI > delete The method according to claim 1,
Wherein the decolorizing agent is a mixture containing ammonia and hydrogen peroxide. The method of claim 3,
Wherein the ammonia and the hydrogen peroxide are mixed in a weight ratio of 1: 9 to 9: 1. delete The method according to claim 1,
The step of forming the cork layer of the thin film comprises:
And peeling the cork material taken from the natural cork wood in the longitudinal direction or the transverse direction. The method according to claim 1,
The step of forming the cork layer of the thin film comprises:
Crushing a cork material taken from a natural cork tree to form a cork chip; And
Mixing and pressing the cork chip and the binder;
≪ / RTI > characterized in that the method comprises the steps of: delete The method according to claim 1,
Wherein the resin layer is formed by attaching the resin sheet using an adhesive or by attaching the resin sheet to one surface of the cork layer by a thermocompression bonding method. delete

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