KR20200003616A - Adhesive protective film for exposure process - Google Patents

Abstract

The present invention relates to an adhesive protective film for a light exposure process. The adhesive protective film for a light exposure process of the present invention is a film on which an adhesive layer formed of an adhesive composition containing an acrylic copolymer is laminated on one surface of a base film layer. The present invention: optimizes the glass transition temperature and thickness of the adhesive layer; attaches an adhesive protective film to a photo solder resist (PSR) printing process before UV exposure during a PCB manufacturing process; smoothens a UV exposure process by protecting the PSR ink surface of tack characteristics; has no adhesive residue when PSR ink is fully cured after UV exposure and a protective film is peeled off after the corresponding process; has excellent peeling properties by having little time-variant change in a peeling strength of the protective film before and after the UV exposure; and thus reduces peeling defects generated when a protective film is peeled off.

Description

Adhesive protective film for exposure process {ADHESIVE PROTECTIVE FILM FOR EXPOSURE PROCESS}

The present invention relates to an adhesive protective film for an exposure process, and more particularly, to an adhesive layer formed of an adhesive composition containing an acrylic copolymer on one surface of a base film layer, wherein the glass transition temperature and thickness of the adhesive layer are increased. By optimizing, adhesion protective film is attached to PSR (Photo Solder Resist) printing process before UV exposure during rigid printed circuit board (PCB) manufacturing process, making PSR process smooth and tack characteristics. Protection of PSR ink surface of UV and sufficient curing of PSR ink after UV exposure and no adhesive residue when peeling off protective film after the process. It relates to a protective film.

PCB is a circuit connecting part that electrically connects and supports electronic parts and semiconductors by forming conductor patterns such as copper on insulating plates such as phenol and epoxy.

It is an essential component that is basically installed in all electronic and information communication devices such as home appliances, computers, automobiles, aircraft, etc. Among these, electronic components of semiconductors must be mounted on PCBs to enable circuit connection and function display.

In a typical package, the bonding between the carrier and the die uses a wire, which is bonded to the surface of the carrier and connects the die and the carrier with a wire. At this time, the length of the wire is generally about 1 to 5mm and the diameter is about 25 to 35㎛.

As a term for a method of electrically connecting a die and a package carrier such as a PCB or a leadframe, flip chip bonding technology has been introduced in all sectors of the semiconductor industry.

In the case of flip chip bonding technology, a bump is formed of a conductor material formed on the die surface when the die is bonded to the carrier in the package.The bump-formed surface is formed after the bump is formed on the die. Is directly bonded to.

This flip chip substrate is used as a substrate for semiconductor chips for micro-processes in computers and other electronic devices, and uses more data due to less data loss because it directly transmits electrical signals to balls than conventional lead frames. It is becoming.

Due to these advantages, the usage of flip chips in the rigid substrate market is expected to increase, and the usage of the process protective adhesive film during manufacturing is expected to increase.

That is, in order to manufacture a flip chip substrate, it has excellent heat resistance so that initial adhesion at room temperature, high temperature drying, and change in adhesive strength after UV exposure are stabilized. Thus, the process adhesive can protect the surface of the product during the flip chip manufacturing process and make the process smooth. Protective film is required.

Such an adhesive protective film is used in a PSR (Photo Solder Resist) printing process during various processes of manufacturing a flip chip substrate.

The PSR process is a process of applying permanent epoxy solder mask inks to prevent bridges of soldering solder and prevent oxidation of exposed circuits during component mounting.

Through this process, there is a need to protect the ticky PSR ink surface until UV exposure. Since it is a protective film attached to the surface of PSR ink having tack characteristics, it is necessary to minimize physical and chemical reactions with PSR ink, and to suppress the increase of adhesive strength due to heat generated during UV exposure.

On the other hand, when using a low curing adhesive and a protective film having a low transmittance, there is a problem that the adhesive force of the protective film before and after the UV exposure, the pressure-sensitive adhesive transition, the lack of PSR ink curing occurs. Therefore, a protective film having excellent transmittance and less adhesive force before and after UV exposure is required.

The present inventors have tried to solve the conventional problems, as a result, by providing a pressure-sensitive adhesive film for the exposure process of the pressure-sensitive adhesive layer formed of a pressure-sensitive adhesive composition containing an acrylic copolymer on one surface of the base film layer, PSR before UV exposure during the PCB manufacturing process (Photo Solder Resist) Adhesion protection film is attached to the printing process to facilitate the PSR process, protect the surface of PSR ink with tack characteristics, sufficient curing of PSR ink after UV exposure, and adhesive residue when peeling off the protection film after the corresponding process. The present invention was completed by confirming that the protective film peeling force before and after the UV exposure was small and the peelability was excellent, thereby reducing the peeling defect generated when the protective film was peeled off.

Republic of Korea Patent Publication No. 2017-0090229 (2017.08.07 published) Korean Patent Publication No. 2009-0122906 (published Dec. 1, 2009)

An object of the present invention is attached to the PSR printing process before UV exposure during the manufacturing process of the flip chip substrate of the rigid PCB to protect the PSR ink surface of the tack characteristics, the exposure process minimizes the change in the peel force over time when peeling off the protective film after UV exposure It is to provide an adhesive protective film for.

In order to achieve the above object, the present invention provides an adhesive protective film for an exposure process in which a pressure-sensitive adhesive layer formed of a pressure-sensitive adhesive composition containing an acrylic copolymer is laminated on one surface of the base film layer and the base film layer.

In this case, the acrylic copolymer is 85 to 96% by weight of a soft acrylic monomer having a glass transition temperature of 0 ° C. or less, 1 to 10% by weight of a hard acrylic monomer having a glass transition temperature of 0 ° C. or more and 3 to 5% by weight of a functional-containing monomer. It consists of.

The soft acryl monomer consists of butyl (meth) acrylate, ethyl acrylate, hexyl methacrylate, n-propyl (meth) acrylate, n-tetradecyl (meth) acrylate and 2-ethylhexyl acrylate It is to use at least one selected from.

In addition, the hard acryl monomer uses at least one selected from the group consisting of methyl acrylate, methyl methacrylate, ethyl methacrylate, vinyl acetate, styrene and acrylonitrile.

In the pressure-sensitive adhesive film for an exposure process of the present invention, the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer is composed of 1.0 to 5 parts by weight of an epoxy curing agent, based on 100 parts by weight of the acrylic copolymer, the acrylic copolymer has a carboxyl functional group and glass transition temperature. It is preferable that it is -55 degreeC --20 degreeC.

Therefore, it is preferable that the adhesion layer of this invention is 95% or more in hardening degree, and is 2-6 micrometers in thickness.

In the pressure-sensitive adhesive film for an exposure process of the present invention, the thickness of the base film layer preferably meets the requirements of 8 to 25㎛.

The pressure-sensitive adhesive film for an exposure process of the present invention that satisfies the above requirements satisfies 89% or more of total light transmittance and 5% or less of haze.

In addition, the pressure-sensitive adhesive protective film for the exposure process of the present invention is 5 to 10gf / 25mm adhesive force before UV exposure, 5 to 10gf / 25mm after UV exposure, and before and after UV exposure to the PSR (Photo Solder Resist) ink surface Minimized change in the peeling force of the protective film over time.

According to the present invention can provide a pressure-sensitive adhesive film for an exposure process in which a pressure-sensitive adhesive layer formed of a pressure-sensitive adhesive composition containing an acrylic copolymer on one surface of the base film layer.

Adhesion protection film that controls the glass transition temperature and thickness of the adhesive layer is attached to a PSR (Photo Solder Resist) printing process before UV exposure during PCB manufacturing process to protect the surface of PSR ink with tack characteristics, thereby smoothing the UV exposure process. In addition, there is no adhesive residue when sufficient curing of PSR ink after UV exposure and protective film peeling after the process, and there is little change of protective film peeling force with time before and after UV exposure, so that the peelability is excellent, and the peeling defect generated during peeling of the protective film can be reduced. Can be.

1 is a schematic cross-sectional view of an adhesive protective film for an exposure process according to the present invention.

Hereinafter, the present invention will be described in detail.

1 is a schematic cross-sectional view of an adhesive protective film for an exposure process according to an embodiment of the present invention, the present invention is a pressure-sensitive adhesive composition containing an acrylic copolymer on the base film layer (1) and one surface of the base film layer (1) Provided is an adhesive protective film for an exposure process in which the formed adhesive layer 2 is laminated.

In addition, since the formation of the release film layer 3 on one side of the adhesive layer 2 may be used without particular limitation as long as it is used in the adhesive film field, in the present specification, the base film layer 1 and the adhesive layer 2 may be mainly used. Explain.

In the pressure-sensitive adhesive film for exposure steps of the present invention, the pressure-sensitive adhesive layer 2 is formed of a pressure-sensitive adhesive composition containing an acrylic copolymer.

Specifically, the acrylic copolymer is 85 to 96% by weight of a soft acrylic monomer having a glass transition temperature of 0 ° C. or less, 1 to 10% by weight of a hard acrylic monomer having a glass transition temperature of 0 ° C. or more and 3 to 5% by weight of a functional-containing monomer. Is formed.

The soft acrylic monomer having a glass transition temperature of 0 ° C. or lower imparts flexibility and adhesion to the pressure-sensitive adhesive film for an exposure process of the present invention. For this purpose, it is selected from the group consisting of butyl (meth) acrylate, ethyl acrylate, hexyl methacrylate, n-propyl (meth) acrylate, n-tetradecyl (meth) acrylate and 2-ethylhexyl acrylate. One or more is used. More preferably, at least one selected from the group consisting of butyl acrylate, ethyl acrylate and 2-ethylhexyl acrylate is used.

In addition, the hard acrylic monomer having a glass transition temperature of 0 ° C. or more functions to impart cohesion to the pressure-sensitive adhesive film for the exposure process of the present invention. One or more selected from the group consisting of methyl acrylate, methyl methacrylate, ethyl methacrylate, vinyl acetate, styrene and acrylonitrile can be used for this purpose, more preferably methacrylate or methylacrylate Is selected.

The acrylic copolymer has a characteristic of adhesiveness according to the glass transition temperature, and the adhesive itself has viscoelasticity, which in this case is more biased toward the elastic side. In this case, the protective film should act as a protection against foreign objects or external shocks. If the elasticity is high and the viscosity becomes low, the external film may not absorb the external shocks and damage the product.

The wettability of the adhesive layer to the adherend depends on the cohesion force of the adhesive layer or the thickness of the adhesive layer. That is, when the cohesive force of the pressure-sensitive adhesive layer is increased, the wettability against bending of the surface of the substrate layer is lowered.

Therefore, the wettability of the adherend can achieve the properties required by the glass transition temperature of the copolymer and the thickness control of the adhesive film.

Accordingly, the glass transition temperature of the acrylic copolymer of the present invention is preferably -55 ° C to -20 ° C, more preferably -45 ° C to -35 ° C, and most preferably has a carboxyl functional group and a glass transition temperature. It is -45 degreeC or more. At this time, when the glass transition temperature is less than -55 ° C, even if the pressure-sensitive adhesive composition is cured to have a three-dimensional network configuration, the glass transition temperature of the polymer itself is low, so that deformation occurs during high temperature evaluation, causing problems in heat resistance. On the other hand, when the glass transition temperature exceeds -20 ° C, when the pressure-sensitive adhesive composition is cured, the molecular structure is more densely formed than the composition having a low glass transition temperature, which is not preferable.

In order to make the glass transition temperature (Tg) of the acrylic copolymer above -55 ° C, the type and polymerization ratio of each monomer should be appropriately selected.

First, the tack property (sticky degree of the adhesive) in the film-type pressure sensitive adhesive of the present invention is determined by the blending of the soft acrylic monomer and the hard acrylic monomer in the monomer components constituting the adhesive. At this time, if the content of the soft acrylic monomer is increased, the glass transition temperature of the adhesive layer is lowered and the tack characteristics are increased, and if the content of the hard acrylic monomer is increased, the glass transition temperature of the adhesive layer is increased and the tack characteristics are decreased. do.

Therefore, the content of the soft acrylic monomer is preferably 85 to 96% by weight, if the content is less than 85% by weight, the content of the hard acrylic monomer is increased, the glass transition temperature of the copolymer is high, whereas 96% by weight If it exceeds%, the content of the hard acrylic monomer is relatively reduced, and the glass transition temperature of the copolymer is lowered.

In addition, the hard acrylic monomer is preferably contained in an amount of 1 to 10% by weight, and when it exceeds 10% by weight, the pressure-sensitive adhesive becomes hard, the tackiness (Tacky) may fall and the adhesion to the adherend may be inferior.

In addition, the weight average molecular weight of the acrylic copolymer used in the present invention is preferably 300,000 to 2 million, if the weight average molecular weight is less than 300,000, the adhesive residual phenomenon due to the decrease in cohesion occurs, and if it exceeds 2 million, It is unpreferable because a viscosity becomes high, workability | operativity worsens, molecular weight rises, and the elasticity and adhesive force of an adhesive rise.

In addition, the thickness of the heat-resistant protective film adhesive layer for the exposure process according to the invention is characterized in that the dry coating thickness is 2 to 6㎛, the adhesion to the PSR ink is 5 to 10g / 25mm.

When the thickness of the adhesive layer is thinner than 2 μm, the adhesion to the PSR ink is inferior, and the PSR ink is pressed by the R chip roughness of the film. When the thickness of the adhesive layer is thicker than 6 μm, the adhesive force increases and the UV of the PSR ink is increased. The gloss decreases after exposure.

In addition, if the adhesive force is less than 5g / 25mm, peeling may occur during the process, if it exceeds 10g / 25mm, it may cause the peeling failure such as PSR ink surface damage, PSR ink peeling during removal.

The acrylic copolymer of the present invention uses a functional-containing monomer as a crosslinking monomer to copolymerize and synthesize the above-mentioned soft acrylic monomer and hard acrylic monomer. For this purpose, at least one selected from the group consisting of monomers containing hydroxy groups, monomers containing carboxyl groups and monomers containing nitrogen is used. At this time, the monomer containing the hydroxy group is 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) ) Acrylate, 2-hydroxy ethylene glycol (meth) acrylate or 2-hydroxypropylene glycol (meth) acrylate, and the like, and the monomer containing the carboxyl group includes (meth) acrylic acid, maleic acid or fumaric acid. As the monomer containing nitrogen, acrylamide, N-vinyl pyrrolidone, N-vinyl caprolactam and the like are used. The above functional containing monomers may be used alone or in combination of two or more.

It is preferable to contain 3 to 5 weight% of monomers which have the said functional group. At this time, if the content is less than 3% by weight, the curing density is lowered, the cohesive force of the pressure-sensitive adhesive is lowered, if it exceeds 5% by weight, the pot life after the addition of the curing agent when the pressure-sensitive adhesive is compounded (pot life) becomes a problem.

The curing agent used in the pressure-sensitive adhesive layer (2) of the pressure-sensitive adhesive film for exposure process according to the present invention can be used in various ways depending on the concentration of the curing agent, epoxy curing agent to improve the curing rate, heat resistance.

Specifically, it contains 1.0-5 weight part of epoxy hardening | curing agents with respect to 100 weight part of said acrylic copolymers. At this time, when the content of the curing agent is less than 1.0 part by weight, the degree of curing may be lowered to less than 95% and crosslinking may not be sufficiently achieved. If the content of the curing agent exceeds 5 parts by weight, an excess amount of the curing agent more than the functional group of the acrylic adhesive enters the side reaction. May cause. At this time, it is preferable that the adhesive layer 2 satisfies 95% or more of the curing degree.

In the pressure-sensitive adhesive film for an exposure process according to the present invention, the base film layer 1 is a polyester polymer such as polyethylene terephthalate and polyethylene naphthalate, an acrylic polymer such as polymethyl methacrylate, polystyrene and acrylonitrile-styrene. Styrene-type polymers, such as a copolymer (AS resin), a polycarbonate polymer, etc. can be used.

Also, polyolefin polymers such as polyethylene, polypropylene, cyclo or norbornene structures, polyolefin polymers such as ethylene-propylene copolymers, amide polymers such as vinyl chloride polymers, nylon and aromatic polyamides, imide polymers, Phon polymer, polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, allylate polymer, polyoxymethylene polymer , Epoxy polymers, blend polymers of the above polymers, acrylic, urethane, acrylic urethane, and epoxy or silicone based thermosetting or ultraviolet curing resins are preferably used alone or in combination.

Therefore, the base film layer 1 is most preferably a polyethylene terephthalate (PET) film, the thickness of the base film layer can be applied in various ways, it is preferably 8 to 25㎛. At this time, if the thickness of the base film layer is less than 8㎛, workability due to poor lamination when laminating the protective film processability, the adhesive protective film in the UV exposure process, and when it exceeds 25㎛, the wettability to PSR ink is poor Although the adhesive force is low, there is a problem that a poor UV exposure occurs in which stains occur between the patterns after the UV exposure.

The pressure-sensitive adhesive film for exposure steps of the present invention obtained from the above characteristics satisfies the properties of total light transmittance of 89% or more and haze of 5% or less. At this time, if the haze is high, a problem occurs that a stain occurs in the PSR ink when the adhesive protective film is peeled off due to insufficient exposure after the UV exposure process.

In addition, the pressure-sensitive adhesive film for the exposure process of the present invention with respect to the PSR (Photo Solder Resist) ink surface, the adhesion before UV exposure is 5 to 10gf / 25mm, by implementing the adhesion after UV exposure 5 to 10gf / 25mm, UV An adhesive protective film for an exposure process with little change in adhesive force before and after exposure can be provided.

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

This embodiment is intended to illustrate the present invention in more detail, and the scope of the present invention is not limited to these examples.

Production Examples 1 to 6 Preparation of Acrylic Copolymers 1 to 4 and Preparation of Adhesion Layer Containing the Same

<Example 1>

On the PET base film layer having a total light transmittance of 90% and a thickness of 12 µm, 3.0 g of an epoxy curing agent was uniformly mixed with 100 g of acrylic copolymer 2 according to the conditions of Preparation Example 2 of Table 1, and then coated with a thickness of 6 µm. 1 minute at 160 ℃ to form an adhesive layer (PSA).

Comparative Example 1

On a PET base film layer having a total light transmittance of 90% and a thickness of 12 µm, 0.5 g of an epoxy curing agent was uniformly mixed with 100 g of acrylic copolymer 2 according to the conditions of Preparation Example 1 of Table 1, and then coated with a thickness of 6 µm. And dried at 160 ℃ for 1 minute to prepare a sample with an adhesive layer (PSA).

Comparative Example 2

On the PET base film layer having a total light transmittance of 90% and a thickness of 12 µm, 6 g of an epoxy curing agent was uniformly mixed with 100 g of acrylic copolymer 2 according to the conditions of Preparation Example 3 of Table 1, and then coated to a thickness of 6 µm. It dried for 1 minute at 160 degreeC, and prepared the sample in which the adhesion layer (PSA) was formed.

Comparative Example 3

On the PET base film layer having a total light transmittance of 90% and a thickness of 12 µm, 3 g of an isocyanate curing agent was uniformly mixed with 100 g of acrylic copolymer 4 according to the conditions of Preparation Example 6 of Table 1, and then coated to a thickness of 6 µm. It dried for 1 minute at 160 degreeC, and prepared the sample in which the adhesion layer (PSA) was formed.

<Comparative Example 4>

On the PET base film layer having a total light transmittance of 90% and a thickness of 12 µm, 100 g of an acrylic copolymer 1 and 3 g of an epoxy curing agent were uniformly mixed according to the conditions of Preparation Example 4 of Table 1, and then coated to a thickness of 6 µm. It dried for 1 minute at 160 degreeC, and prepared the sample in which the adhesion layer (PSA) was formed.

Comparative Example 5

On the PET base film layer having a total light transmittance of 90% and a thickness of 12 μm, 3 g of an epoxy curing agent was uniformly mixed with 100 g of an acrylic copolymer 3 according to the conditions of Preparation Example 5 of Table 1, and then coated to a thickness of 6 μm. It dried for 1 minute at 160 degreeC, and prepared the sample in which the adhesion layer (PSA) was formed.

Comparative Example 6

On the PET substrate film layer having a total light transmittance of 90% and a thickness of 12 µm, 3 g of an epoxy curing agent was uniformly mixed with 100 g of acrylic copolymer 2 according to the conditions of Preparation Example 2 of Table 1, and then coated with a thickness of 1.5 µm. It dried for 1 minute at 160 degreeC, and prepared the sample in which the adhesion layer (PSA) was formed.

Comparative Example 7

On the PET base film layer having a total light transmittance of 90% and a thickness of 12 µm, 3 g of an epoxy curing agent was uniformly mixed with 100 g of acrylic copolymer 2 according to the conditions of Preparation Example 2 of Table 1, and then coated with a thickness of 8 µm. It dried for 1 minute at 160 degreeC, and prepared the sample in which the adhesion layer (PSA) was formed.

<Comparative Example 8>

On the PET substrate film layer having a total light transmittance of 90% and a thickness of 6 µm, 3 g of an epoxy curing agent was uniformly mixed with 100 g of acrylic copolymer 2 according to the conditions of Preparation Example 2 of Table 1, and then coated to a thickness of 6 µm. It dried for 1 minute at 160 degreeC, and prepared the sample in which the adhesion layer (PSA) was formed.

Comparative Example 9

On the PET base film layer having a total light transmittance of 90% and a thickness of 30 μm, 3 g of an epoxy curing agent was uniformly mixed with 100 g of acrylic copolymer 2 according to the conditions of Preparation Example 2 of Table 1, and then coated to a thickness of 6 μm. It dried for 1 minute at 160 degreeC, and prepared the sample in which the adhesion layer (PSA) was formed.

Comparative Example 10

On the PET base film layer having a total light transmittance of 88% and a thickness of 12 μm, 3 g of an epoxy curing agent was uniformly mixed with 100 g of acrylic copolymer 2 according to the conditions of Preparation Example 2 of Table 1, and then coated to a thickness of 6 μm. It dried for 1 minute at 160 degreeC, and prepared the sample in which the adhesion layer (PSA) was formed.

Experimental Example

1.Measurement of adhesive thickness

The thickness of the adhesive layer was measured for the samples prepared in Example 1 and Comparative Examples 1 to 10 using a micrometer.

2. Measurement of adhesive force before and after UV exposure after laminating the adhesive protective film after printing PSR ink

After the samples prepared in Example 1 and Comparative Examples 1 to 10 were laminated with the surface printed with PSR ink, before and after room temperature and UV exposure, 30 minutes after AR-1000 measuring equipment, a speed of 0.3 m / min, 180 Peeling was measured at an angle to measure the adhesion.

3.PSR ink surface appearance check

When the samples prepared in Examples 1 and Comparative Examples 1 to 10 were laminated with the PSR ink printed surface, and then peeled off the PSA protective film before and after UV exposure, PSA residue, PSR ink dropout, PSR ink marks, gloss, etc. The appearance of the was confirmed.

4. Check the optical properties (light transmittance, Haze)

After the release film was peeled off the samples prepared in Example 1 and Comparative Examples 1 to 10, total light transmittance and haze were measured by a D65 light source using an NDH-2000 measuring apparatus in PET + PSA form.

5. Measurement of Curing Degree of Adhesive Layer

Scrape off the fully cured pressure-sensitive adhesive on the base film, check the weight of the cured pressure-sensitive adhesive, put the scratched pressure-sensitive adhesive on a mesh of 180 mesh, soak in solvent (MEK) for about 1 day, and then volatilize the solvent (MEK) entirely. Then, the weight of the remaining pressure-sensitive adhesive was measured.

The degree of curing of the pressure-sensitive adhesive layer was selected by the following formula on the basis of the measured weight.

Adhesive hardening degree = weight of adhesive after 1 day ÷ initial weight of adhesive × 100

From the result of Example 1, after the functional group has a carboxyl group, using an epoxy curing agent and 100g of an acrylic copolymer having a glass transition temperature of -55 to -20 ℃, uniformly mixed in an amount of 1.0 to 5 parts by weight of the epoxy curing agent When the total light transmittance is 89% or more and the adhesive layer PSA is coated with a thickness of 2 to 6 μm on a base film layer PET having a thickness of 8 to 25 μm, the PSR (Photo Solder Resist) ink may be selected. Before and after the UV on the surface having the characteristics was confirmed excellent adhesion and appearance.

On the other hand, in the case of Comparative Example 1 and Comparative Example 2, compared to the conditions of Example 1, as a result of varying the epoxy curing agent content, Comparative Example 1 (0.5g) when the epoxy curing agent content is reduced, the degree of curing is reduced before and after UV PSR (Photo Solder Resist) A problem of dropping PSR ink after UV exposure was found due to high adhesive strength of the ink surface.

On the other hand, Comparative Example 2 (6g) when the content of the epoxy curing agent was increased, there was no problem in the degree of curing and surface appearance, it was confirmed that the problem caused by the side reaction during UV exposure due to the excessive amount of the curing agent to increase the adhesive strength.

In Comparative Example 3, in contrast to Example 1, when the curing agent was prepared using an isocyanate curing agent in an acrylic copolymer having a hydroxyl group functional group, the adhesion to the PSR ink before UV exposure was good (OK), but after UV exposure. When peeling off the protective film, an increase in adhesive force and a realistic look were generated.

Comparative Examples 4 and 5 changed the glass transition temperature of the acrylic copolymer. In Comparative Example 4, the glass transition temperature of the acrylic copolymer was lowered to −55 ° C., and the residue of the adhesive remained after UV exposure. In Comparative Example 5, the glass transition temperature of the acrylic copolymer was decreased to −20 ° C. During the evaluation, the problem occurred that the PSR ink was not attached.

In addition, Comparative Examples 6 and 7 changed the adhesive thickness. Comparative Example 6 caused a problem in that pinholes were generated in the PSR ink due to the roughness of PET recycled chip when the adhesive thickness was measured at 1.5 μm, and Comparative Example 7 was a film prepared by coating the adhesive thickness at 8 μm. In the case of evaluation, it was confirmed that the gloss of the PSR ink decreased in the appearance side after UV exposure.

Comparative Examples 8 and 9 changed the PET thickness. Comparative Example 8 was coated with a PET thickness of 6㎛ as in Example. There was no specificity in terms of physical properties, but the workability was reduced due to poor lamination of the protective film processability and lamination of the adhesive protective film in the UV exposure process. Comparative Example 9 was coated as in Example on a PET thickness of 30㎛. As the PET thickness became thicker, the wettability to PSR ink was lowered, and the adhesion was low. However, a poor UV exposure resulted in spots between patterns after UV exposure.

Comparative Example 10 was evaluated using PET having a total light transmittance of less than 89%. The high haze and the lack of exposure after the UV exposure process caused a problem of staining of the PSR ink when the adhesive protective film was peeled off.

As described above, according to the present invention, while protecting the surface of the PSR ink having a sticky (sticky), reducing the protective film peeling failure due to the suppression of the adhesive force increase before and after UV exposure and the worker load during the protective film peeling operation, etc. The adhesive protection film for the exposure process was provided.

The adhesive protective film for the exposure process of the present invention facilitates the manufacturing process of the printed circuit board, and protects the surface of the substrate from external influences so that the exposure process can be carried out smoothly. It is possible.

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

1: base film layer 2: adhesive layer 3: release film layer

Claims (9)

Base film layer and
It consists of an adhesive layer formed of an adhesive composition containing an acrylic copolymer on one surface of the base film layer,
The acrylic copolymer is composed of 85 to 96% by weight of a soft acrylic monomer having a glass transition temperature of 0 ° C or less, 1 to 10% by weight of a hard acrylic monomer having a glass transition temperature of 0 ° C or more, and 3 to 5% by weight of a functional-containing monomer. Adhesive protective film for exposure process. The method of claim 1, wherein in the acrylic copolymer, the soft acrylic monomer is butyl (meth) acrylate, ethyl acrylate, hexyl methacrylate, n-propyl (meth) acrylate, n- tetradecyl (meth) acrylate And 2-ethylhexyl acrylate, and at least one selected from the group consisting of
The hard acrylic monomer is at least one selected from the group consisting of methyl acrylate, methyl methacrylate, ethyl methacrylate, vinyl acetate, styrene and acrylonitrile. The pressure-sensitive adhesive film for an exposure process according to claim 1, wherein the pressure-sensitive adhesive composition comprises 1.0 to 5 parts by weight of an epoxy curing agent, based on 100 parts by weight of the acrylic copolymer. The pressure-sensitive adhesive film for an exposure process according to claim 1, wherein the acrylic copolymer has a carboxyl functional group and a glass transition temperature is -55 ° C to -20 ° C. The pressure-sensitive adhesive film for an exposure process according to claim 1, wherein the pressure-sensitive adhesive layer has a degree of curing of 95% or more. The pressure-sensitive adhesive film for an exposure process according to claim 1, wherein the pressure-sensitive adhesive layer has a thickness of 2 to 6 μm. The pressure-sensitive adhesive film for an exposure process of claim 1, wherein the base film layer has a thickness of 8 to 25 μm. According to claim 1, wherein the pressure-sensitive adhesive film for the exposure process
Total light transmittance is over 89%,
Adhesive protective film for exposure processes, characterized in that the haze is 5% or less. The method of claim 1, wherein the pressure-sensitive adhesive film for the exposure process with respect to the PSR (Photo Solder Resist) ink surface,
Adhesion before UV exposure is 5-10gf / 25mm,
Adhesive protective film for an exposure process, characterized in that the adhesion after the UV exposure is implemented in 5 to 10gf / 25mm.

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