KR101932621B1 - Manufacturing method of adhesion film for insert injection molding - Google Patents

Abstract

A method of manufacturing an insert injection film capable of being adhered to a dissimilar material is disclosed.
The method for manufacturing an insert injection film according to the present invention comprises the steps of: (a) coating a base film with a polyester resin to prepare a first film; (b) coating a surface of the first film with a thermosetting resin to form a binder layer; And (c) thermally lapping a second film comprising a thermoplastic film on the binder layer, wherein after step (c), one surface of the first film is bonded to a metal material, 2 One side of the film is characterized by adhering to a plastic material.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for manufacturing an insert injection film,

The present invention relates to a process for producing an adhesive film, and more particularly, to a process for producing an adhesive film for insert injection which can be adhered to a dissimilar material including a plastic material and a metal material.

Composite materials in which metal materials and plastic materials are integrated are generally used for molding of mobile phones, washing machines, electronic products, automobiles, and the like. The composite material is protected or decorated with the surface of a component mainly by an insert injection process. For example, an adhesive is applied between a metal material and a plastic material, or a metal material and a plastic are thermally fused to each other.

However, these methods have limitations in the adhesive strength and have limitations in the field of use of the composite material.

On the other hand, it is possible to produce a composite material in which a metal material and a plastic material are integrated by using a two-layer adhesive film composed of an adhesive film on the metal material side and an adhesive film on the plastic material side, The type of film that can be applied is limited.

Therefore, it is necessary to develop an adhesive film which is excellent in adhesive force, can change various types of films, and can be applied to insert injection between different kinds of materials.

A background art related to the present invention is disclosed in Korean Patent Laid-Open Publication No. 10-2004-0032016 (Apr. 14, 2004), which discloses a method for producing an insert molding film.

It is an object of the present invention to provide a method for producing an adhesive film for insert injection which can be applied to automobile interior materials, exterior materials and electronic products.

According to an aspect of the present invention, there is provided a method of manufacturing an insert injection film for injection molding, comprising: (a) coating a polyester resin on both sides of a base film to produce a first film; (b) coating a surface of the first film with a thermosetting resin to form a binder layer; And (c) thermally lapping a second film comprising a thermoplastic film on the binder layer, wherein after step (c), one surface of the first film is bonded to a metal material, 2 One side of the film is characterized by adhering to a plastic material.

The polyester resin of the step (a) may have a glass transition temperature (Tg) of -5 ° C to 30 ° C.

The polyester resin in the step (a) may include at least one of a hydroxyl group, a carboxyl group, an amino group, an epoxy group, an acrylate group and maleic anhydride.

The thermosetting resin in the step (b) may include at least one of a urethane resin, an epoxy resin and a phenol resin.

The thermoplastic film of step (c) may include at least one of a polypropylene film, a nylon film, an acrylonitrile butadiene styrene (ABS) film, a polyvinyl chloride (PVC) film, and a polycarbonate (PC) film.

The coatings of steps (a) and (b) may be performed by a Ti-die coating, a slot die coating, a comma coating, a microcomma coating or a gravure coating.

In the step (c), the thermal lamination may be performed by applying a pressure of 1 to 10 kgf / cm ² G at 50 to 200 ° C.

In the step (c), the surface of the second film may be subjected to a corona surface treatment, a plasma surface treatment, or a primer surface treatment.

In the step (a), the thickness of the first film may be 10 to 30 占 퐉.

In the step (b), the thickness of the binder layer may be 10 to 30 탆.

In the step (c), the thickness of the second film may be 10 to 80 탆.

According to the present invention, it is possible to produce an adhesive film having a three-layer structure which can be adhered to a different material including a metal material and a plastic material by laminating a first film, a binder layer and a second film.

Particularly, a first film is produced by using a polyester capable of maintaining adhesion with a metal material, and a second film capable of being varied in accordance with the type of the plastic to be injected is produced, whereby the adhesion between the metal surface and the plastic surface is excellent It is effective.

In addition, the metal to which the adhesive film is adhered can be processed into a desired size and shape, and the injection resin can be injected into the processed metal material and bonded at the same time.

1 is a flowchart showing a method of manufacturing an insert injection film according to the present invention.
Fig. 2 is a cross-sectional view of an insert injection film used in a method of insert injection-molding plastic into a metal material according to the present invention.
3 is a perspective view of stainless steel (SUS 304) prepared for adhesion evaluation.
Fig. 4 is a perspective view of a specimen obtained by thermally fusing an insert injection-use adhesive film according to the present invention to the stainless steel of Fig. 3;
5 is a perspective view of a composite material specimen produced by injection molding the specimen of Fig. 4 with an injection resin.
6 is a conceptual view showing the principle of insert injection in the related art.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for manufacturing an insert injection film according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Referring to Fig. 6, the insert injection is generally performed by the temperature of the resin to be injected. Fig. 6 (a) shows an example in which an adhesive or an adhesive film is formed on a metal, and Fig. 6 (b) shows an example in which a metal material and a plastic material are bonded by injection heat generated when the resin is injected.

1 is a flowchart showing a method of manufacturing an insert injection film according to the present invention.

Referring to FIG. 1, the method for manufacturing an insert injection film according to the present invention includes a first film production step (S110), a binder layer formation step (S120), and a second film heat consolidation step (S130).

In the first film production step (S110)

First, a base film is coated with a polyester resin to prepare a first film.

The base film may be a PET film, a PVC film or the like, but it is preferable to use a PET film in consideration of the point coated with a polyester resin and compatibility with a resin.

The polyester resin contains an ester (R-COO-R) group in the molecular chain. Since the non-covalent electron pairs in the oxygen of the ester group enhance the adhesion to the metal, the polyester resin has excellent adhesion between the metal material and the first film .

The polyester resin preferably has a glass transition temperature (Tg) of -5 ° C to 50 ° C, more preferably 30 ° C to 50 ° C, in order to self-adhere to a metal material. When the glass transition temperature is lower than -5 ° C, the adhesive strength between the metal material and the first film is excellent due to the self-adhesive force, but the physical properties of the finished article (composite material) may be deteriorated due to insufficient heat resistance temperature of 80 to 110 ° C. On the contrary, when the glass transition temperature is higher than 50 ° C., a high heat of 250 ° C. or more is required when the laminated first film is thermally laminated to the metal, and in this case, there is a problem that deformation of the laminated second film occurs.

The glass transition temperature is the point at which the polymer begins to move with the molecules being activated by the temperature, indicating the point where the change appears before the phase change. As the glass transition temperature, the softening point, and the melting point order, the temperature becomes higher and the viscosity becomes lower.

The polyester resin may have a softening point of 80 캜 or higher.

The polyester resin may be a polyester resin containing at least one of a hydroxyl group, a carboxyl group, an amino group, an epoxy group, an acrylate group and maleic anhydride so as to maintain a good adhesion with a metal material. These functional groups have respective non-covalent electron pairs in the molecule, and by molecular force, van der Waals force, non-covalent electron pairs provide excellent adhesion between the metal surface and the molecule.

10 to 50% of the polyester resin and 50 to 90% of an organic solvent may be mixed and coated on both sides of the base film. Alternatively, 100% of the polyester resin may be coated on both sides of the base film without using an organic solvent .

Examples of the organic solvent include toluene, methyl ethyl ketone, acetone, xylene, isopropyl alcohol, and the like.

The coating can be carried out with a Ti-die coating, a slot die coating, a comma coating, a micro-comma coating or a gravure coating. By such a coating method, the first film can be formed with a thickness of 10-30 탆. When the thickness of the first film is less than 10 mu m, the adhesive strength of the first film is lowered. When the thickness of the first film is more than 30 mu m, only the thickness is increased without increasing the adhesion force.

After coating, the first film may be dried at room temperature to completely remove the organic solvent. In addition, the organic solvent may be dried in a semi-cured resin in which 10 to 90% of the organic solvent is removed, but the present invention is not limited thereto.

As described above, since the polyester resin is coated on the base film to a predetermined thickness, one side of the first film can be adhered to the metal material during injection molding to exhibit excellent adhesion.

The binder layer forming step (S120)

Next, a thermosetting resin is coated on one surface of the first film to form a binder layer. The binder layer is a layer for bonding the first film and the second film, and the adhesive layer can be given strength. That is, the binder layer is cured by heat or ultraviolet rays, so that the three-layer structure of the adhesive film can be integrated.

Accordingly, it is preferable to use a thermosetting resin having excellent compatibility with the thermoplastic resin of the polyester resin of the first film and bonding of the second film to the binder layer.

The thermosetting resin may include at least one of a urethane-based resin, an epoxy-based resin and a phenol-based resin, and preferably includes a urethane-based resin. The polyurethane resin has functional groups such as -NH-COO-, -COO-, -OH, and -NCO and is widely used as a reactive adhesive. Particularly, since the -NCO group has a high activity, it reacts with the -OH group to exhibit excellent adhesion, and the polyurethane resin containing such a functional group is easy to control the curing reaction and exhibits excellent flexibility and durability.

Further, a one-pack type or two-pack type thermosetting resin can be used, and a second film can be produced using a composition in which 15 to 70% of the thermosetting resin is mixed with 30 to 85% of an organic solvent. The distinction between one-component type and two-component type is generally confirmed by the use of a curing agent.

The coating can be carried out with a Ti-die coating, a slot die coating, a comma coating, a micro-comma coating or a gravure coating. According to such a coating method, the binder layer can be formed to a thickness of 10 to 30 mu m, and when the thickness is less than 10 mu m, the adhesion strength between the first film and the second film is deteriorated. When the thickness exceeds 30 mu m, The thickness only increases without the effect of the thickness.

The second film thermal lamination step (S130)

Next, the second film including the thermoplastic film is heat-laminated on the binder layer.

Since one side of the second film is bonded to the plastic material, it is preferable that the second film includes a thermoplastic film which can be changed according to the injection resin. For example, the thermoplastic film may be a polypropylene film, a nylon film, an ABS (acrylonitrile butadiene styrene) film, a polyvinyl chloride (PVC) film, a polycarbonate 0.0 > (PC) < / RTI > films.

Further, the second film may be formed of a thermoplastic film having properties of stretching, lead-free, uniaxial stretching or biaxial stretching. The stretched film is arranged in a direction in which the molecular arrangement is stretched and the mechanical strength is increased in the stretched direction. The uniaxially stretched film has a directionality of strength and therefore tends to be easily torn in a direction in which stretching is not performed. The biaxially stretched film has similar mechanical strengths in the transverse and longitudinal directions, thereby increasing the mechanical strength of the film, while shrinking the film during heating.

Therefore, in order to minimize the shrinkage or distortion of the adhesive film during injection molding of the metal material and the plastic material, it is preferable to use a lead-free film. A cast film is a film prepared by melt-extruding a thermoplastic resin and cooling it with a cooling roll, as opposed to a stretched film.

In order to maintain the shape of the adhesive film after the injection molding, glass fiber, mineral fiber, or the like may be included in the second film.

For example, a composition containing 10 to 40 parts by weight of glass fibers per 100 parts by weight of a polypropylene resin may be melt-extruded to produce a second film.

The glass fiber and mineral fiber are melted at the time of injection and exhibit an adhesive force, and the compatibility and adhesion between the first film and the second film can be improved.

The glass fiber, mineral fiber and the like contained in the second film may have an average particle diameter of 0.1 to 10 mu m and an average length of 0.1 to 10 mm, but the present invention is not limited thereto.

In addition, the second film may be one having a surface subjected to a corona surface treatment, a plasma surface treatment, or a primer surface treatment. The surface treatment is carried out on both sides or one side of the second film, so that it is possible to exhibit an adhesive force more than five times higher than that of the second film on which the conventional surface treatment is not performed. The surface of the surface-treated second film may exhibit a wet number of 25 dynes or more. The wettability index is a measure of how much liquid is spread evenly over the surface. When the viscosity is 25 dyne or more, the second film exhibits excellent adhesion and excellent workability at the time of injection.

The corona surface treatment and the plasma surface treatment temporarily reform the surface, and a high voltage is flowed between the two electrodes to ionize the air between the discharge electrode and the treatment substrate by the generated high frequency or low frequency, And these particles change the surface of the object, thereby improving adhesion and adhesion.

The primer surface treatment is applied for protecting the surface of an object, and the kind of the coating liquid may be changed depending on the material of the part to be painted.

The thickness of the second film including the thermoplastic film is preferably 10 to 80 占 퐉, more preferably 10 to 30 占 퐉. Outside this range, the adhesion may be deteriorated, and as the thickness of the second film is thicker, the sense of unity between the metal and the injection resin is lost and the satisfaction of the appearance design is lowered. The unity refers to the appearance tolerance of the finished product at the time of injection, maintenance of watertightness, and the like.

The heat lamination can be carried out by applying a pressure of 1 to 10 kgf / cm ² G at 10 to 150 ° C using a drum roll press machine. When the heat shrinkage is carried out at a temperature lower than 10 캜, adhesion between the first film and the second film may not be sufficiently achieved, and when the heat shrinkage is carried out at a temperature exceeding 150 캜, Can be lowered.

When the pressure is less than 1 kgf / cm ² G, adhesion between the first film and the second film may be insufficient. When the pressure exceeds 10 kgf / cm ² G, the thickness deviation of the three- And the adhesion property may be deteriorated due to the deviation in the thickness of the adhesion between the metal and the injection molding at the time of injection.

As described above, the method for producing an adhesive film for insert injection according to the present invention can exhibit excellent adhesion between different materials by a three-layer structure in which a thermosetting resin is formed of a binder layer.

By producing the first film and the binder layer by coating, a uniform thickness can be maintained, and the second film can be thermally joined to produce an integrated adhesive film for insert injection.

As shown in FIG. 2, the insert injection adhesive film produced in the present invention can be press-worked in a size and shape to be produced after thermally laminated on one side of a metal material, and after the press operation, the finished product assembly is solidified Forming.

The specimen thus prepared is mounted in an insert injection machine and injected together with an injection resin to produce a composite material adhered to a dissimilar material including a metal material and a plastic material. The manufactured composite material is applicable to automobile interior materials, exterior materials and electronic products.

A specific example of the method for manufacturing the insert injection film will be described below.

1. Manufacture of adhesive film for insert injection

Examples 1 to 3

The PET base film was coated with a polyester resin having a glass transition temperature of 40 캜 using a Tie die coating method to prepare a first film. The polyester resin includes a carboxyl group (COOH).

A polyurethane resin was coated on one side of the first film using a Ti-die coating method to form a binder layer.

Next, the open at 60 ℃ under a pressure of 5kgf / cm ^2, a polypropylene film (second film) on the binder layer laminated to prepare an adhesive film for insert molding.

Examples 4 to 6

The PET base film was coated with a polyester resin having a glass transition temperature of 40 캜 using a slot die coating method to prepare a first film. The polyester resin includes a carboxyl group (COOH).

A solvent-modified polyurethane resin was coated on one surface of the first film and dried to form a binder layer. The lean polyurethane resin was prepared by mixing 30% of ethanol and 70% of polyurethane resin.

Next, the open at 60 ℃ under a pressure of 5kgf / cm ^2, a polypropylene film (second film) on the binder layer laminated to prepare an adhesive film for insert molding.

Example 7

An adhesive film for insert injection was produced in the same manner as in Example 1 except that the corona surface treatment was performed on both sides of the polypropylene film.

Example 8

An adhesive film for insert injection was produced in the same manner as in Example 4 except that the corona surface treatment was applied to both sides of the polypropylene film.

Example 9

An adhesive film for insert injection was produced in the same manner as in Example 7, except that 40 parts by weight of glass fiber was contained in the second film.

The glass fibers had an average particle diameter of 10 mu m and an average length of 10 mm.

Comparative Example 1

A polypropylene copolymer containing a carboxyl group was extruded into a film type to prepare a first film, and a polypropylene resin was extruded into a film type to prepare a second film.

The first film and the second film were laminated together, and then a pressure of 5 kgf / cm ² was applied at 100 ° C to produce an adhesive film.

Comparative Example 2

The PET base film was coated with a polyester resin having a glass transition temperature of 40 캜 using a Tie die coating method to prepare a first film. The polyester resin includes a carboxyl group (COOH).

A polyurethane film was extruded and coated on one side of the first film using a Ti-die coating method to produce an adhesive film.

[Table 1]

2. Property evaluation method and result

The adhesion of the specimens prepared in Examples 1 to 4 and Comparative Example 1 was measured.

As shown in Fig. 3, stainless steel (SUS 304) was prepared.

As shown in Fig. 4, the first film of the test piece was thermally fused to be adhered to stainless steel, and the heat fusing temperature was 200 占 폚.

This specimen was put into an injection machine and injected with a polypropylene resin as an injection resin so that one side of the second film was bonded to the polypropylene plastic as shown in Fig.

The adhesive strength was measured using ASTM D1002.

The shape of the composite material is indicated as "poor", "good", "excellent" when visually observed, and "poor" indicates that the composite material is twisted , "Good" is the case where the metal and the plastic material are excited, and "Excellent" is the case where both the adhesive force and the shape of the composite material are excellent.

[Table 2]

Referring to Table 1 and Table 2, in Examples 1 to 6, the adhesive strength was 7 to 8 kg / cm ² . In particular, in Examples 7 to 8, in which the second film was surface-treated, adhesion strength was 5 times or more as compared with Examples 1 to 6.

On the other hand, in Comparative Examples 1 and 2, the adhesive film was formed into a two-layer structure, and the adhesive force was lower than in Examples 1 to 6.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It is to be understood that the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

10: First film
20: Second film
30: Binder layer
40: Adhesive film for insert injection
80: metal
90: Plastic

Claims (11)

(a) coating a base film with a polyester resin to produce a first film;
(b) coating a surface of the first film with a thermosetting resin to form a binder layer; And
(c) thermally lapping a second film comprising a thermoplastic film on the binder layer,
Wherein one side of the first film is adhered to a metal material and the other side of the second film is adhered to a plastic material after the step (c).
The method according to claim 1,
The polyester resin of the step (a)
Wherein the glass transition temperature (Tg) is -5 占 폚 to 50 占 폚.
The method according to claim 1,
Wherein the polyester resin in step (a) comprises at least one of a hydroxyl group, a carboxyl group, an amino group, an epoxy group, an acrylate group and maleic anhydride.
The method according to claim 1,
Wherein the thermosetting resin in step (b) comprises at least one of a urethane resin, an epoxy resin and a phenol resin.
The method according to claim 1,
Wherein the thermoplastic film of step (c) comprises at least one of a polypropylene film, a nylon film, an acrylonitrile butadiene styrene (ABS) film, a polyvinyl chloride (PVC) film, and a polycarbonate A method for producing an adhesive film for injection.
The method according to claim 1,
The coating of step (a) and step (b)
Wherein the coating is carried out by a tie dye coating, a slot die coating, a comma coating, a microcomma coating or a gravure coating.
The method according to claim 1,
In the step (c), the heat lamination is performed by applying a pressure of 1 to 10 kgf / cm ² G at 10 to 150 ° C.
The method according to claim 1,
Wherein in the step (c), the surface of the second film is subjected to a corona surface treatment, a plasma surface treatment, or a primer surface treatment.
The method according to claim 1,
Wherein the thickness of the first film in the step (a) is 10 to 30 占 퐉.
The method according to claim 1,
Wherein the thickness of the binder layer in the step (b) is 10 to 30 占 퐉.
The method according to claim 1,
Wherein the thickness of the second film in the step (c) is 10 to 80 占 퐉.

Images