KR100838461B1 - Surface protective film - Google Patents

Abstract

A surface protection film is provided to prevent an adhesive from being stuck and an object from being damaged in removing an adhesive film, by maintaining sufficient adhesion with the object before a hot compression process by increasing the initial adhesive power, and keeping the increase of adhesive power within three times during hot compression. A releasable surface protection film is composed of: a base film(10) and an adhesion composition formed inside the base film. The adhesion composition for the surface protection film contains acrylic resin of 100wt.% having a carboxylic functional group and an epoxy hardening agent of 1~4wt.%. An adhesive layer(20) is formed by coating the base film with the adhesion composition in the coating thickness of 6~18 micrometers.

Description

Surface protective film {Surface protective film}

1 is a schematic view showing the structure of a surface protection film according to an embodiment of the present invention.

※ Explanation of codes for main parts of drawing

10: base film

20: adhesive layer

30: release film

The present invention relates to an adhesive composition for a surface protection film and a surface protection film using the same, and more particularly, to an adhesive composition for a surface protection film and a surface protection film using the same to protect the surface of the product from damage in the manufacturing process of the flexible product. It is about.

In the present specification, the inner side of the base film means the side on which the pressure-sensitive adhesive layer and the release film are formed, and the outer side of the base film means the opposite side to the inner side.

Unlike printed circuit boards (PCBs), FCCL or copper foil used in the manufacture of flexible printed circuit boards (FPCBs) is flexible and thin, so the polyimide film of FCCL It is necessary to attach a protective film to cotton or copper foil to facilitate the handling of the material during the manufacturing process and to protect and maintain it safely.

As a film for surface protection according to the prior art, a heat-resistant re-peelable pressure-sensitive adhesive film having a heat-resistant base material and an adhesive layer has an intermediate that enhances adhesive strength between the heat-resistant base material and the pressure-sensitive adhesive layer. By applying, the difference of the adhesive force after normal temperature and heating was adjusted to within 4 times (Lintec company patent: Unexamined-Japanese-Patent No. 2000-44896).

The technique forms an intermediate between the pressure-sensitive adhesive layer and the base film, which is disadvantageous in that the process is added and the overall thickness is increased without any advantage other than enhancing adhesion.

Furthermore, the use of acrylic resins and isocyanate-based curing agents causes the isocyanate-based curing agent to cause an increase in adhesive force during the high temperature compression process, causing a transition of the adhesive when the protective film is removed after high temperature compression, and the adhesive force is high and the curl of the FPCB curls. There is also a problem that causes a defect that generates (curl).

In another prior art, a functional group having a hydroxyl group is provided in order to provide a pressure-sensitive adhesive composition which does not generate floating from the adherend during heat treatment, there is no excessive increase in adhesive force, and there is no adhesion of contaminants to the adherend during peeling. There is one in which an isocyanate-based curing agent is applied to an acrylic resin (Toyo Ink Co., Japanese Patent Application Laid-Open No. 2006-22313).

However, also in the above technique, by using acrylic resin and isocyanate curing agent, as described above, the isocyanate curing agent causes an increase in adhesive force in the high temperature compression process, and thus the transition of the adhesive during removal of the protective film after high temperature compression is prevented. Induced, the adhesive force is high, there is a problem that causes a defect that generates the curl (curl) of the FPCB.

In the case of designing low initial adhesive force to lower the adhesive strength after high temperature compression to solve the problems in the prior arts, printing, exposure, peeling, corrosion, development due to the occurrence of poor adhesion from the adherend before the high temperature compression process In the washing and drying process, the protective film is lifted up, which causes the product to be defective.

In addition, conventionally, since the coating work for the protection during the manufacturing process is made in a general protective equipment, foreign matters such as agglomerates and dust on the surface of the adhesive coating film, the foreign matter when laminating the protective film to FCCL or copper foil There was a problem that the defect caused by.

In practical experiments, however, isocyanate-based curing agents do not prevent the increase in adhesion under high temperature compression conditions of acrylic resins, and work in ordinary adhesive coating workshops without special facilities in dust-free rooms prevents the generation of foreign matter in the film. If the initial adhesive force is designed to prevent an increase in adhesive force, as described above, printing, exposure, peeling, corrosion, development, washing and drying may occur due to the occurrence of poor adhesion from the adherend before the high temperature compression process. Lifting of the protective film occurs in the process, which causes product defects.

The present invention is to solve the problems of the prior art as described above, an object of the present invention, in the pressure-sensitive adhesive composition for a surface protection film and the surface protection film using the same, a film coated with a pressure-sensitive adhesive on a PET film which is a heat resistant substrate Heat resistance, chemical resistance, re-peeling which can be adhered to one side of FCCL polyimide film or copper foil to proceed the process without damaging FCCL during printing, exposure, peeling, corrosion, developing, cleaning, drying and high temperature compression process of pattern It is to provide a surface protective film having the properties.

Another object of the present invention is to increase the initial adhesive strength than the existing product to maintain a sufficient adhesion with the object to be deposited until the high-temperature compression process, but the increase in the adhesive strength in the high-temperature compression is less than three times, there is no transition of the adhesive when removing the adhesive film It is to provide a surface protective film as an adhesive protective film for process protection without damage to ash.

The present invention for achieving the above object relates to a surface protection film and a pressure-sensitive adhesive composition constituting the same which has a strong chemical resistance and small changes in the adhesive force even under high temperature and high pressure environment to protect the damage of the product.

The present invention is prepared based on the adhesive coating technology and the appropriate formulation and application technology of the polymer resin.

In order to achieve the above object, the present invention provides a surface protective film comprising a base film, a pressure-sensitive adhesive layer formed on the inner surface of the base film, and a release film formed on the pressure-sensitive adhesive layer.

According to one embodiment of the present invention, the pressure-sensitive adhesive composition for a surface protection film constituting the surface protection film as described above contains an acrylic resin and an epoxy curing agent having a carboxyl functional group.

In addition, according to a preferred embodiment of the present invention, the pressure-sensitive adhesive composition contains 1 to 4 parts by weight of an epoxy curing agent based on 100 parts by weight of an acrylic resin having a carboxyl functional group.

Hereinafter, an adhesive composition for a surface protection film and a surface protection film using the same according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic view showing the configuration of a surface protection film according to an embodiment of the present invention.

As shown in FIG. 1, in the surface protection film according to the exemplary embodiment of the present invention, an adhesive layer 20 is formed on an inner side surface of the base film 10, and a release film 30 is formed on the adhesive layer 20. ) Is formed.

First, in this invention, when forming the adhesive layer 20 on the base film 10, it is preferable to add a hardening | curing agent at 1.0-4.0 weight part with respect to 100 weight part of normal adhesive components.

Thus, with respect to 100 parts by weight of the main ingredient, when the curing agent is contained in an amount of 1.0 to 4.0 parts by weight, not only the initial adhesive strength is high but also it is preferable in minimizing the increase in adhesive force in the high temperature compression process.

That is, when the pressure-sensitive adhesive composition is formed, when the curing agent is contained in an amount of 1.0 to 4.0 parts by weight in each composition, the initial adhesive strength is high in a high-temperature compression process while the curing agent is contained in an amount of less than 1.0 part by weight or more than 4.0 parts by weight. It has the effect of reducing the increase in adhesion.

A general pressure sensitive adhesive may be used as the subject of the pressure sensitive adhesive composition. In the present invention, an acrylic resin having a functional group of a carboxyl group may be used. It is preferable to use an epoxy type hardening | curing agent as said hardening | curing agent.

Therefore, as the pressure-sensitive adhesive composition for a surface protection film according to an embodiment of the present invention, it is preferable to include an epoxy curing agent in an amount of 1.0 to 4.0 parts by weight based on 100 parts by weight of the acrylic resin having a carboxyl functional group.

As a manufacturing method of an adhesive composition, the said subject and the said hardening | curing agent are put into the said composition, and the method of mixing for 10 minutes is used.

Regarding the configuration of the adhesive composition in the pressure-sensitive adhesive layer 20 according to an embodiment of the present invention, an acrylic pressure-sensitive adhesive in which a carboxyl group or a hydroxyl group is used alone as a functional group or a carboxyl group and a hydroxyl group is used in combination may be adopted. And an isocyanate curing agent or an epoxy curing agent to find an appropriate ratio.

In the case of isocyanate-based curing agent, the effect of lowering the initial adhesive strength was excellent, but the adhesive strength after high temperature compression resulted in an increase.

Therefore, the resin finally selected is a coating of a compound using an epoxy curing agent on an acrylic pressure-sensitive adhesive containing a carboxyl functional group, which has a high initial adhesive force and a small increase in adhesive strength after high temperature compression.

Coating equipment according to an embodiment of the present invention, the adhesion of the coating head portion and the drying chamber in the 100 ~ 1,000 class level equipment by applying the environment of the coating equipment in a dust-free room. This prevents the incorporation of dust and foreign substances (impurity) in the coating film, and works with three or less foreign substances of 100 μm or more per M ² .

Thereby, it becomes possible to prevent the copper foil deterioration defect or the adhesive film lifting defect by the foreign matter mixing of the existing process protection carrier film.

In addition, the coating head is coated with a coma coater to maintain the viscosity of the coating solution at 500 to 2,000 cps / 25 ° C, and the surface roughness after coating is less than Ra 0.3 ± 0.1, Rz 2.5 ± 0.3, Rmax 4.0 ± 0.3 To be

A solvent is used to maintain the viscosity of the coating solution, and the solvent is not particularly limited as long as it can dissolve an adhesive composed of an adhesive composition and a curing agent. For example, toluene, methyl ethyl ketone, isopropyl alcohol, cyclohexanone, ethyl acetate, or a mixed solvent thereof can be used.

Next, in the configuration of the base film 10 according to an embodiment of the present invention, the base film 10 is a film made using a material having a heat resistance, a heat-resistant resin having a thickness in the range of 10 ~ 200㎛ Use the film.

Such heat resistant resins include, for example, polyester resins such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, and polyimide resins. It is preferable to use base materials, such as a polycarbonate resin, a polystyrene resin, a polyamide resin, a polyester imide resin, and a polyester ether resin.

In the MD and TD directions, the film has a tensile strength of at least 16 kg / mm ² or more, an elongation of at least 80%, and a heat shrinkage of at least 1.8% in the MD direction at a temperature of 150 ° C. for 30 minutes. It will prevent deformation.

In short, as described above, the present invention is to use the epoxy-based curing agent in the acrylic resin having a carboxyl functional group as the adhesive composition for the surface protection film working in the coating equipment in a dust-free room according to one embodiment .

Hereinafter, the present invention will be described in more detail by explaining preferred examples and experimental examples of the present invention.

However, the present invention is not limited to the following examples, and various forms of embodiments can be implemented within the scope of the appended claims, and the following examples are only ordinary in the art while making the disclosure of the present invention complete. It is intended to facilitate the implementation of the invention to those with knowledge.

Experimental Example-Example and Comparative Example

The film lamination | stacking structure of each Example and a comparative example in this experimental example is as follows (the base film 10 and the release film 30 may be any of the thing as mentioned above).

Example  1 (epoxy curing agent 1.5 Parts by weight  1 ~ 2 By weight  I got the same result in the range Example  Expressed as 1)

Base film 10 / pressure-sensitive adhesive layer 20-1: 1.5 parts by weight of an epoxy-based curing agent in 100 parts by weight of the acrylic pressure-sensitive adhesive containing a carboxyl group / release film 30

Example  2 (epoxy curing agent 2.5 Parts by weight  2 ~ 3 By weight  I got the same result in the range Example  Expressed as 2)

Base film 10 / pressure-sensitive adhesive layer 20-2: 2.5 parts by weight of an epoxy-based curing agent in 100 parts by weight of the acrylic pressure-sensitive adhesive containing a carboxyl group / release film 30

Example  3 (epoxy curing agent 3.5 Parts by weight  3 ~ 4 By weight  I got the same result in the range Example  Expressed as 3)

Base film 10 / pressure-sensitive adhesive layer (20-3): 3.5 parts by weight of an epoxy-based curing agent in 100 parts by weight of the acrylic pressure-sensitive adhesive containing a carboxyl group / release film (30)

Comparative example  1 (isocyanate curing agent 1.5 Parts by weight  1 ~ 2 By weight  I got the same result in the range Comparative example  Expressed as 1)

Substrate film 10 / pressure-sensitive adhesive layer (20-4): 1.5 parts by weight of isocyanate-based curing agent to 100 parts by weight of the acrylic pressure-sensitive adhesive containing a hydroxyl group compounded / release film (30)

Comparative example  2 (isocyanate curing agent 3.5 Parts by weight  2 ~ 4 By weight  I got the same result in the range Comparative example  Expressed as 2)

Base film 10 / pressure-sensitive adhesive layer (20-5): 3.5 parts by weight of isocyanate-based curing agent to 100 parts by weight of the acrylic pressure-sensitive adhesive containing a hydroxyl group compounded / release film (30)

Comparative example  3 (isocyanate curing agent 4.5 Parts by weight  4 ~ 5 By weight  I got the same result in the range Comparative example  Expressed as 3)

Base film 10 / pressure-sensitive adhesive layer (20-6): 4.5 parts by weight of isocyanate-based curing agent to 100 parts by weight of the acrylic pressure-sensitive adhesive containing a hydroxyl group compound / release film (30)

Comparative example  4

Substrate film 10 / pressure-sensitive adhesive layer (20-7): 0.9 parts by weight of an epoxy-based curing agent in 100 parts by weight of the acrylic pressure-sensitive adhesive containing a carboxyl group / product release film (30)

Comparative example  5

Substrate film 10 / pressure-sensitive adhesive layer (20-8): 4.1 parts by weight of an epoxy-based curing agent in 100 parts by weight of the acrylic pressure-sensitive adhesive containing a carboxyl group / release film (30)

The pressure-sensitive adhesive composition (20-1 to 20-3) used in Examples 1 to 3 was prepared by adding 1 to 4 parts by weight of epoxy resin in the respective ratios relative to 100 parts by weight of the acrylic resin containing a carboxyl group. Toluene was used as the solvent for coating workability in the coater to maintain the proper viscosity. The blended composition was coated on a polyethylene terephyhalate (PET) film based on a comma coater so as to have a dry coating thickness of 6 μm or less, 6 μm to 15 μm, 15 μm to 18 μm, and 18 μm or more, to form an adhesive layer. At the time of winding up, the release film was laminated | stacked on the adhesive layer, and the surface protection film which consists of a base material / an adhesive layer / a release film was obtained. In order to cure this surface protective film, it was aged for 7 days at 23 ° C. and 50% RH atmosphere.

The pressure-sensitive adhesive compositions (20-4 to 20-6) used in Comparative Examples 1 to 3 were prepared by adding 1 to 5 parts by weight of isocyanate resins in the respective ratios relative to 100 parts by weight of the acrylic resin containing a hydroxyl group. . Toluene was used as the solvent for coating workability in the coater to maintain the proper viscosity. The blended composition is coated on a polyethylene terephyhalate (PET) film based on a comma coater to have a dry coating thickness of 6 μm or less, 6 μm to 15 μm, 15 μm to 18 μm, and 18 μm or more, to form an adhesive layer. At the time of winding up, the release film was laminated | stacked on the adhesive layer, and the surface protection film which consists of a base material / an adhesive layer / a release film was obtained. In order to cure this surface protective film, it was aged for 7 days at 23 ° C. and 50% RH atmosphere.

The pressure-sensitive adhesive compositions (20-7 and 20-8) used in Comparative Examples 4 to 5 were prepared by mixing 0.9 and 4.1 parts by weight of epoxy resins in respective corresponding ratios with respect to 100 parts by weight of acrylic resin containing carboxyl groups. Toluene was used as the solvent for coating workability in the coater to maintain the proper viscosity. The blended composition is coated on a polyethylene terephyhalate (PET) film based on a comma coater so as to have a dry coating thickness of 6 μm or less, 6 μm to 15 μm, 15 μm to 18 μm, and 18 μm or more, to form an adhesive layer. At the time of winding up, the release film was laminated | stacked on the adhesive layer, and the surface protection film which becomes a base material / adhesive layer / release film was obtained. In order to cure this surface protective film, it was aged for 7 days at 23 ° C. and 50% RH atmosphere.

[Adhesion Test Measurement at Room Temperature]

The pressure-sensitive adhesive film prepared in each of the above examples and each comparative example was cut into 25mm * 120mm in the MD direction, and each specimen was attached to a polyimide film (Apical 25NPI) and laminated at a weight of 4kgf / cm. Leave for 60 minutes in the atmosphere of% RH. Thereafter, when the sample is peeled at a peel angle of 180 ° and a peel rate of 300 mm / min, the stress on the sample is measured.

[Comparison test of adhesion after treatment]

The adhesive films prepared in each example and each comparative example were cut into 25mm * 120mm in the MD direction, and each specimen was attached to a polyimide film (Apical 25NPI) and laminated at a weight of 4kgf / cm. After pressing for 1 hour at 180 ℃, 40kgf / cm pressure and left for 60 minutes in an atmosphere of 23 ℃, 50% RH. Thereafter, when the sample is peeled at a peel angle of 180 ° and a peel rate of 300 mm / min, the stress on the sample is measured.

[Lifting comparative measurement experiment]

The adhesive film prepared in each example and each comparative example was cut into 100mm * 100mm, and each specimen was attached to FCCL (Flexible Copper Clad Laminate) and laminated at a weight of 4kgf / cm. After heat-processing for time, it removes from an oven and is left to stand for 60 minutes in 25 degreeC and 50% RH atmosphere. At this time, the presence or absence of lifting between the adhesive film and FCCL is measured.

[Comparison measurement experiment after curl state after heating]

After attaching each specimen cut 20 mm * 120 mm in the TD direction of the adhesive film prepared in each example and each comparative example to the FCCL (Flexible Copper Clad Laminate) and laminated at a weight of 4kgf / cm pressure, and left for 30 minutes, this sample Heated at 180 ° C. in an oven. Then, it took out and left for 20 minutes in 25 degreeC and 50% RH atmosphere, and the curl state of the sample was observed.

[Comparative Measurement Experiment of Substance after Peeling]

When the adhesive film of each specimen used in the curl test described above was peeled by hand slowly and the other half was quickly peeled off by T-shaped peeling, there was no external damage (bend, breakage of the copper foil, etc.) of the adherend. Check it.

[Comparative Measurement Experiment of Substance Contamination after Peeling]

When the adhesive film of each target used in the curl test mentioned above was peeled off by hand slowly and the other half was carried out by T-shaped peeling off quickly, it is confirmed that there is no trace of an adhesive on the polyimide surface of CCL.

The results of comparative measurements by performing experiments according to the above Examples and Comparative Examples are shown in Tables 1 and 2, respectively.

As can be seen from the above, the acrylic resin and isocyanate-containing acrylic resin containing carboxyl group and the isocyanate-based or containing carboxyl group are contained by including acrylic resin and carboxyl group containing carboxyl group in the pressure-sensitive adhesive composition of the pressure-sensitive adhesive layer. Compared with the composition of the adhesive composition including the cyanate-based, the initial adhesive strength was maintained the same and at the same time, even after performing the high temperature compression process, the increase in the adhesive strength could be relatively small.

Therefore, there is no transition of the adhesive when the adhesive film is removed, and it is possible to manufacture a process protection adhesive protective film without damage to the adherend.

In the case of Comparative Examples 1 to 3, it can be seen that the adhesive strength after the high-temperature compression process is significantly increased compared to the initial adhesive force, thereby causing the transition of the adhesive when removing the protective film after high-temperature compression, accordingly Problems that cause contamination of the adherend state will appear.

In the case of Comparative Examples 4 to 5, the epoxy curing agent was less than 1.0 parts by weight and more than 4.0 parts by weight, and the condition of the adherend after peeling was poor or the problem of adherend contamination appeared.

According to the present invention, in the surface protection film, a film coated with an adhesive on a PET film, which is a heat resistant substrate, is attached to the FCCL polyimide film surface or one side of the copper foil to print, expose, peel, corrode, develop, and wash the pattern. It is possible to provide a protective film having heat resistance, chemical resistance, and re-peelability that can be performed without damaging the FCCL during the drying, high temperature compression process.

In other words, the initial adhesive force is higher than the existing product, and the adhesive force rises within 3 times while maintaining sufficient adhesion with the object to be deposited until the high temperature compression process, so that there is no transfer of the adhesive when the adhesive film is removed and no damage to the adherend. It is possible to manufacture a process protection adhesive protective film.

Although the present invention has been described in connection with the above-mentioned preferred embodiments, it is possible to make various modifications or variations without departing from the spirit and scope of the invention. Accordingly, the appended claims should cover such modifications and variations as fall within the spirit of the invention.

Claims (9)

Base film; And a pressure-sensitive adhesive composition for a surface protection film formed on an inner side surface of the base film. The adhesive composition for the surface protection film contains an acrylic resin and an epoxy curing agent having a carboxyl functional group, It contains 1-4 weight part of said epoxy-type hardeners with respect to 100 weight part of acrylic resin which has the said carboxyl group functional group, The surface protection film characterized by the above-mentioned. Base film; And a pressure-sensitive adhesive composition for a surface protection film formed on an inner side surface of the base film. The adhesive composition for the surface protection film contains an acrylic resin and an epoxy curing agent having a carboxyl functional group, 1 to 4 parts by weight of the epoxy-based curing agent is contained with respect to 100 parts by weight of the acrylic resin having the carboxyl group, and the adhesive composition is coated on the base film to have a dry coating thickness of 6 to 18 μm to form an adhesive layer. Surface protection film, characterized in that. Base film; And a pressure-sensitive adhesive composition for a surface protection film formed on an inner side surface of the base film. The adhesive composition for a surface protective film is an acrylic resin having a carboxyl functional group; And an epoxy-based curing agent, 1 to 4 parts by weight of the epoxy-based curing agent is contained with respect to 100 parts by weight of the acrylic resin having the carboxyl group, and the adhesive composition is coated on the base film to have a dry coating thickness of 6 to 18 μm to form an adhesive layer. Become, The surface protective film has an initial adhesive strength of 10 to 30g / 25mm at the time of lamination, and a surface protective film of 10 to 40g / 25mm after heat compression. The method according to any one of claims 1 to 3, The base film is a film made using a material having heat resistance, a surface protective film, characterized in that to use a film having a thickness in the range of 10 ~ 200㎛. The method of claim 4, wherein The material having heat resistance may be a polyester resin, a polyimide resin, a polycarbonate resin, a polystyrene resin, a polyamide resin, a polyester imide resin, Surface protective film, characterized in that any one of the polyester ether (polyeter ether) resin. The method according to any one of claims 1 to 3, The base film is a surface protective film using a film having a tensile strength of 16kg / mm ² or more, elongation of 80% or more, and heat shrinkage of 1.8% or less in both MD and TD directions. The method according to any one of claims 1 to 3, Surface protective film using a PET film as the base film. The method according to any one of claims 1 to 3, The surface protection film further comprises a release film formed on the pressure-sensitive adhesive composition. The method of claim 8, Surface protective film, characterized in that using the PET film coated with silicone on one side as the release film.

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