KR20100047701A - Protecting film - Google Patents

Abstract

PURPOSE: A manufacturing method of a protective film is provided to manufacture the protective film which is not damaged by other factors, and to improve strippability and cuttability with initial adhesiveness and proper rigidity. CONSTITUTION: A protective film includes a base film consisting of polypropylene based resin. An adhesive layer including vinyl acetate-based resin containing vinyl acetate 9 ~18 weight%, is laminated on one side or either side of the base film. The adhesive layer includes hydrogenated hydrocarbon resin-based adhesion aiding agent included 0.5 ~ 5 weight%. A melt index of the polypropylene based resin is 3 ~ 9g / 10 minute. A softening point of the adhesion aiding agent is 85 ~ 130°C.

Description

Protective Film

The present invention relates to a protective film for protecting an adherend such as a plastic film or sheet including a prism film.

The prism protective film is used to prevent scratches, contamination, and corrosion of the surface generated during the processing, transportation, or storage of the prism film. Therefore, the prism protective film is temporarily adhered to the surface of the product to achieve the above object. After that, a property that can be easily peeled off is required. In addition, it is required to be economically inexpensive as a one-time product.

Conventionally, as a protective film, a product in which an adhesive such as acrylic or urethane is applied to a base film composed mainly of polyethylene, polyethylene and polypropylene, has been widely used, but such a protective film may be peeled off from the adherend. When the pressure-sensitive adhesive or the undried residual solvent is transferred to the adherend, the problem has been raised, there is a problem that changes over time, such as the adhesive force rapidly changes over time.

In particular, in the case of the prism film, a bead (bead) is coated on the lower surface to improve brightness and releasability, but in the case of the prism film coated on the lower surface, the adhesive strength is lowered when a protective film having a general adhesive force is used. There was a problem of easy peeling.

In addition, since the adhesive force of the protective film varies greatly depending on the material of the coating, when the adhesive material does not match the coating material, the adhesive force of the protective film is too weak to be easily peeled off during transport, and thus the prism film may not be protected or the adhesive force may be too high. During the process of peeling off the protective film from the film was not easily peeled off due to the degradation of the workability of the BLU process and damage to the prism film was not able to properly exhibit the function of the protective film.

Therefore, the adhesion to the prism film coated on the lower surface is excellent, and according to the material of the prism film, a protective film that is easy to control the adhesive force is required.

The present invention is to provide a protective film that is easy to adjust the adhesive force.

In addition, the present invention is a protective film used on the lower surface of the prism film, to provide a protective film that can be easily adjusted according to the material of the prism film.

The present invention is a protective film laminated by co-extrusion of a pressure-sensitive adhesive layer comprising a base film made of a polypropylene resin and a vinyl acetate resin containing 9 to 18% by weight of vinyl acetate units on one or both sides of the base film. The adhesive layer relates to a protective film containing 0.5 to 5% by weight of a hydrogenated hydrocarbon resin-based adhesive aid.

In the present invention, the polypropylene has a melt index (Melt Index, 230 ° C., 2.16 Kg) of 3 to 9 g / 10 minutes, and the vinyl acetate resin has a melt index (Melt Index, 190 ° C., 2.16 Kg) of 1 to 7 g /. Use 10 minutes.

The total thickness of the protective film is 20 ~ 60 ㎛ suitable for use as a protective film, the thickness ratio of the base layer and the adhesive layer is 11: 1 ~ 1: 1 excellent adhesion, curl (curl) Films that do not occur can be produced.

In particular, the protective film of the present invention can be preferably used for the protection of the lower surface of the prism film coated on the lower surface in order to improve the brightness and releasability, to improve the adhesion of the prism film coated on the lower surface, In order to reduce the sudden rise, a vinyl acetate-based resin and an adhesive aid containing 9 to 18% by weight of vinyl acetate units in the adhesive layer are used.

The protective film according to the present invention has an initial adhesive force measured by the method of JIS Z0237 is usually in the range of 1 ~ 5g / 25mm, it is easy to control the adhesive force according to the material of the prism film.

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

In the present invention, the base film is preferably a polypropylene having a melt index (Melt Index, 230 ° C., 2.16 Kg) of 3 to 9 g / 10 min, since it is easy to form a film during coextrusion, and when applied to a prism film manufacturing process. In the cutting process, strength can be maintained without being rolled up. In general, when a mixture of polyethylene or polyethylene and polypropylene used as a protective film is used, the cutting property is lowered, so the present invention is characterized in using polypropylene alone.

The polypropylene may be used as homo-polypropylene, propylene and butadiene or block-co-polypropylene copolymerized with propylene and ethylene, random-co-polypropylene, ter-polypropylene copolymerized with propylene, butadiene and ethylene. The polypropylene resin constituting the base layer may be formulated with additives such as heat stabilizers, ultraviolet absorbers, antistatic agents and antiblocking agents according to a known method. Not good.

If the MI of the polypropylene of the base layer is less than 3.0g / 10 minutes, there is a problem that casting is difficult during coextrusion, and if the MI is more than 9g / 10 minutes, the fluidity is too high to the edge of the die during coextrusion-forming. Only flows.

The adhesive layer is a vinyl acetate-based resin containing 9 to 18% by weight of vinyl acetate units, and is an ethylene-vinylacetate copolymer having a melt index (Melt Index, 190 ° C., 2.16 Kg) of 1 to 7 g / 10 minutes. A total vinyl acetate content of 9 to 18% by weight is used. When the vinyl acetate content is less than 9%, there is a problem that the adhesive force is too low to easily peel off, and when it exceeds 18% by weight, the adhesive strength of the adhesive force to the adherend is too high, which may result in poor peelability.

When the MI of the vinyl acetate-based resin of the adhesive layer is less than 1.0 g / 10 minutes, the casting performance is insufficient and high-speed film formation is difficult, and when the MI exceeds 7 g / 10 minutes, coextrusion with the polypropylene is performed. When fluidity is too good, film forming becomes difficult.

In addition, an adhesive aid is used for the adhesive layer to facilitate the control of the adhesive force. As the adhesive aid, rosin, rosin derivatives, pinene-based resins, hydrocarbon resins, etc. may be used, and among them, petroleum resins are preferably used as adhesive aids for protective films, and more specifically, hydrogenated hydrocarbon resins. System resin is used.

Examples of the petroleum resin include, but are not limited to, aliphatic (C5 fraction, pentene, isoprene, 1,3-pentadiene, etc.), aromatic (C9 fraction, styrene oil, indenes, etc.) aliphatic. -Aromatic copolymers, cycloaliphatic systems, coumarone-indene resins, and the like, and C5 synthetic petroleum resins are preferable from the viewpoint of weather resistance and compatibility with an adhesive agent. Specific examples of such C5 petroleum resin include Eastman's PICCO series, HERCULES series, EXXON's ESCOREZ 5000 series, Kolon's functional material section, SUKOREZ series, Goodyear's WINGTACK series, Zeon's Quintone 100series, and the like. One kind or a combination of two or more kinds can be used.

Although not limited, it is more preferable to use a softening temperature of 85 to 130 ° C. and a specific gravity of 0.8 to 1.2 in the chip transfer step, the chip blending step, and the extrusion film forming step in the extrusion film forming process.

The adhesive aid is preferably used in the range of 0.5 to 5% by weight of the entire composition of the pressure-sensitive adhesive layer, when using less than 0.5% by weight of the adhesion control effect is insignificant, when used in excess of 5% by weight when film forming Fisheye tends to increase and the adhesion is so high that sticking occurs in the film roll, which damages the film.

The protective film according to the present invention is not limited, but the total thickness of the film is preferably 20 to 60 μm. If the film thickness is less than 20㎛, the film forming processability is greatly decreased when the film is formed, and the laminating processability is decreased when the protective film is laminated in the prism film, and the protection function, which is the original function of the protective film, is much lowered. In addition, when the thickness exceeds 60㎛, the economical cost is greatly reduced due to the increase in manufacturing cost due to the thickening of the protective film, and as the thickness is thickened, the winding property is decreased during the film forming process.

In addition, it is preferable that the thickness ratio of the base film and the adhesive layer is from 11: 1 to 1: 1. When the thickness of the base film is thinner than the thickness of the adhesive layer, the adhesive force is improved, but there is a problem in that curl occurs due to the difference in shrinkage between polymers of each layer of the obtained film, and the thickness of the adhesive layer is higher than that of the base layer. If it exceeds 11 times, it is difficult to secure sufficient adhesive strength.

The protective film according to the present invention is in the range of 1 ~ 5g / 25mm adhesive strength measured by the JIS Z0237 method, it can be easily adjusted through the content control of the adhesive aid and the content of the vinyl acetate. If the adhesive force is less than 1g / 25mm, the adhesive force with the prism film is greatly reduced, and the protective film at the edge is peeled off during the cutting process, and foreign materials or damage may occur on the prism sheet.If it exceeds 5g / 25mm, the temperature and temperature after prism film lamination As the adhesive force rises greatly due to the pressure, the protective film is not peeled off in the BLU assembly process, which causes the problem of disposing of the prism film.

The protective film according to the present invention may be manufactured by a coextrusion method, and more specifically, a polypropylene resin constituting the base film is melt-extruded, and a resin and an tackifier are mixed and melt-extruded to form a pressure-sensitive adhesive feed block. Co-extruded and stacked in die.

The present invention has excellent initial adhesiveness and suitable rigidity, has excellent peelability and cutting property, and does not damage the appearance of the prism film, and is excellent in economy by coextrusion, and does not generate curl and prism. According to the coating composition of the lower surface can provide a protective film capable of adjusting the adhesive force.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited only to the following examples.

Unless otherwise described in the following examples, the prism film is a prism coating on the upper surface of the EVERRAY LC type-PET base film, and the lower surface uses a prism sheet coated with a mixture of silicon beads and a release agent having an average particle diameter of 3 μm. It was.

The film forming processability, fish eye, adhesive force, change with time, cutting property and no-curl property of the film specimens prepared according to the following Examples and Comparative Examples were measured using the following method.

(Film forming fairness)

After preparing and weighing each layer of resin and adhesive aid, it was put into each hopper and melt-extruded by two melt extruders and co-extruded through a feed block to form a film laminated through a die-casting method. When preparing the layer film specimens, the film forming processability was evaluated by evaluating the film forming process specificity and the winding property in the winder.

(Fish eye evaluation)

The film formed in the above manner was visually evaluated for a fish eye of 0.2 mm or more, that is, the defects of the film (unmelted, carbide, scratch, etc.) while running on a separate slitter base. Fish eye in the prism protection film usually requires less than 15mm / ㎡ defects of size of 0.2mm or more.

(adhesiveness)

Adhesive force measurement was measured according to JIS-Z0237.

Specifically, the film specimen (25mm × 200mm) was laminated on the lower surface of the prism film by 2kg rolls, and was laminated and adhered to each other by using a universal testing machine (Instron 4303, Instron Co., Ltd.) at a speed of 300mm / min. The peel test was also carried out and the adhesive force (g / 25mm) was measured by the peeling force of a film and an adhesive agent.

(Time-varying-adhesion and transition)

After sticking the film specimen to the lower surface of the prism film under the same conditions as the adhesive force measurement, it was left at 60 ° C. (65% humidity) for 7 days and then in the same manner as in the adhesive force measurement using a universal testing machine (Instron 4303, Instron). It was evaluated by observing the adhesion and the contamination by the transition to the adherend with the naked eye.

(Cleavability)

The film specimen was adhered to the lower surface of the prism film and cut under pressing at a pressure of 600 kg. Then, the cutting property was evaluated by observing the edges falling or the protective film breaking during cutting.

(no-curl)

After peeling the film specimens at 60 ° C. (65% humidity) for 2 hours after adhesion to the lower surface of the prism film, the film was visually dried and observed for no-curl property.

Example 1

Base film, melt index (Melt Index) of 5g / 10 minutes (230 ℃, 2.16Kg), terpoly-propylene containing 5% by weight of butadiene and 5% by weight of ethylene (hereinafter referred to as Terpoly-PP) Was used.

The adhesive layer contains 15% by weight of vinyl acetate, 95% by weight of an ethylene-vinylacetate copolymer (hereinafter referred to as EVA) having a melt index of 3g / 10 minutes (190 ° C, 2.16Kg) and an adhesive aid (Hydrogenated C5 hydrocarbon resin). , Softening temperature 110 ℃, specific gravity 1.0) 5% by weight was used.

After preparing and weighing the resin for each layer, it was put in each hopper and melt-extruded by two melt extruders and co-extruded through a feed block to form a film laminated through a die by a die-casting method. Was 50 μm, the base film was 40 μm, and the adhesive layer was 10 μm.

As the adherend, a prism film was used and the physical properties of the obtained film specimens were measured and the results are shown in Table 2 below.

[Example 2]

As a base film, a block-co-polypropylene (hereinafter referred to as Block-PP) containing a Melt Index of 5 g / 10 minutes (230 ° C., 2.16 Kg) and 5% by weight of ethylene was used.

The adhesive layer contains 15% by weight of vinyl acetate, 95% by weight of an ethylene-vinylacetate copolymer (hereinafter referred to as EVA) having a melt index of 3g / 10 minutes (190 ° C, 2.16Kg) and an adhesive aid (Hydrogenated C5 hydrocarbon resin). , Softening temperature 110 ℃, specific gravity 1.0) 5% by weight was used.

After preparing and weighing the resin for each layer, it was put in each hopper and melt-extruded by two melt extruders and co-extruded through a feed block to form a film laminated through a die by a die-casting method. Was 50 μm, the base film was 40 μm, and the adhesive layer was 10 μm.

As the adherend, a prism film was used and the physical properties of the obtained film specimens were measured and the results are shown in Table 2 below.

Example 3

Base film, a melt index (Melt Index) of 7g / 10 minutes (230 ℃, 2.16Kg), terpoly-propylene containing 5% by weight of butadiene and 5% by weight of ethylene (hereinafter referred to as Terpoly-PP) Was used.

The adhesive layer contains 15% by weight of vinyl acetate and 97% by weight of an ethylene-vinylacetate copolymer (hereinafter referred to as EVA) having a melt index of 1.2 g / 10 minutes (190 ° C and 2.16 Kg) and an adhesive aid (Hydrogenated C5). hydrocarbon resin, softening temperature 110 ℃, specific gravity 1.0) 3% by weight was used.

After preparing and weighing the resin for each layer, it was put in each hopper and melt-extruded by two melt extruders and co-extruded through a feed block to form a film laminated through a die by a die-casting method. Was 50 μm, the base film was 40 μm, and the adhesive layer was 10 μm.

As the adherend, a prism film was used and the physical properties of the obtained film specimens were measured and the results are shown in Table 2 below.

Example 4

As a base film, a block-co-polypropylene (hereinafter referred to as Block-PP) containing a melt index of 7 g / 10 min (230 ° C., 2.16 Kg) and 5% by weight of ethylene was used.

The adhesive layer contains 18% by weight of vinyl acetate and 97% by weight of an ethylene-vinylacetate copolymer (hereinafter referred to as EVA) having a melt index of 1.2g / 10 minutes (190 ° C, 2.16Kg) and an adhesive aid (Hydrogenated C5 hydrocarbon). resin, softening temperature 110 ℃, specific gravity 1.0) 3% by weight was used.

After preparing and weighing the resin for each layer, it was put in each hopper and melt-extruded by two melt extruders and co-extruded through a feed block to form a film laminated through a die by a die-casting method. Was 50 μm, the base film was 40 μm, and the adhesive layer was 10 μm.

As the adherend, a prism film was used and the physical properties of the obtained film specimens were measured and the results are shown in Table 2 below.

Example 5

Base film, a melt index (Melt Index) of 7g / 10 minutes (230 ℃, 2.16Kg), terpoly-propylene containing 5% by weight of butadiene and 5% by weight of ethylene (hereinafter referred to as Terpoly-PP) Was used.

The adhesive layer contains 15% by weight of vinyl acetate and 99.5% by weight of an ethylene-vinylacetate copolymer (hereinafter referred to as EVA) having a melt index of 1.2 g / 10 minutes (190 DEG C, 2.16 Kg) and an adhesive aid (Hydrogenated C5 hydrocarbon). resin, softening temperature 110 ℃, specific gravity 1.0) 0.5% by weight was used.

After preparing and weighing the resin for each layer, it was put in each hopper and melt-extruded by two melt extruders and co-extruded through a feed block to form a film laminated through a die by a die-casting method. Was 50 μm, the base film was 40 μm, and the adhesive layer was 10 μm.

As the adherend, a prism film was used and the physical properties of the obtained film specimens were measured and the results are shown in Table 2 below.

Example 6

As a base film, a block-co-polypropylene (hereinafter referred to as Block-PP) containing a melt index of 7 g / 10 min (230 ° C., 2.16 Kg) and 5% by weight of ethylene was used.

99.5% by weight of an ethylene-vinylacetate copolymer (hereinafter referred to as EVA) containing 18% by weight of vinyl acetate and a melt index of 1.2g / 10 minutes (190 ° C, 2.16Kg) and an adhesive aid (Hydrogenated C5 hydrocarbon) resin, softening temperature 110 ℃, specific gravity 1.0) 0.5% by weight was used.

After preparing and weighing the resin for each layer, it was put in each hopper and melt-extruded by two melt extruders and co-extruded through a feed block to form a film laminated through a die by a die-casting method. Was 50 μm, the base film was 40 μm, and the adhesive layer was 10 μm.

As the adherend, a prism film was used and the physical properties of the obtained film specimens were measured and the results are shown in Table 2 below.

Example 7

As a base film, a block-co-polypropylene (hereinafter referred to as Block-PP) containing a melt index of 7 g / 10 min (230 ° C., 2.16 Kg) and 5% by weight of ethylene was used.

The adhesive layer contains 9% by weight of vinyl acetate and 99.5% by weight of an ethylene-vinylacetate copolymer (hereinafter referred to as EVA) having a melt index of 1.2 g / 10 minutes (190 ° C., 2.16 Kg) and an adhesive aid (Hydrogenated C5 hydrocarbon). resin, softening temperature 110 ℃, specific gravity 1.0) 0.5% by weight was used.

After preparing and weighing the resin for each layer, it was put in each hopper and melt-extruded by two melt extruders and co-extruded through a feed block to form a film laminated through a die by a die-casting method. Was 50 μm, the base film was 40 μm, and the adhesive layer was 10 μm.

As the adherend, a prism film was used and the physical properties of the obtained film specimens were measured and the results are shown in Table 2 below.

Comparative Example 1

As adhesive layer, 15% by weight of vinyl acetate and melt index of 3g / 10 min (190 ℃, 2.16Kg) were used alone, except that the adhesive aid was not used by using ethylene-vinylacetate copolymer alone. Film specimens were prepared in the same manner as in Example 1.

Physical properties of the obtained film specimens were measured and the results are shown in Table 2 below.

Comparative Example 2

The adhesive layer contains 15% by weight of vinyl acetate, 99.7% by weight of an ethylene-vinylacetate copolymer having a melt index of 3 g / 10 minutes (190 ° C, 2.16Kg), and an adhesive aid (Hydrogenated C5 hydrocarbon resin, softening temperature 110). ℃, specific gravity 1.0) A film specimen was prepared in the same manner as in Example 1 except that 0.3 wt% was used.

Physical properties of the obtained film specimens were measured and the results are shown in Table 2 below.

Comparative Example 3

The adhesive layer contains 15% by weight of vinyl acetate, 94% by weight of an ethylene-vinylacetate copolymer having a melt index of 3 g / 10 minutes (190 ° C, 2.16Kg) and an adhesive aid (Hydrogenated C5 hydrocarbon resin, softening temperature 110 ° C). , 1.0 specific gravity was prepared in the same manner as in Example 1 except that 6 wt% was used.

Physical properties of the obtained film specimens were measured and the results are shown in Table 2 below.

[Comparative Example 4]

Except for using a low-density polyethylene resin (hereinafter referred to as LDPE) alone as a base film, a film specimen was prepared and measured in the same manner as in Example 1, and the results are shown in Table 2 below.

[Comparative Example 5]

As the adhesive layer, as in Comparative Example 1, except that 21% by weight of vinyl acetate was used and an ethylene-vinylacetate copolymer (EVA) having a melt index of 2.5 g / 10 min (190 ° C., 2.16 Kg) was used alone. In the same manner, a film specimen was prepared. Physical properties were measured and the results are shown in Table 2 below.

Comparative Example 6

Ethylene-vinylacetate resin (EVA) containing 5% by weight of vinyl acetate and a melt index of 7g / 10min (190 ° C, 2.16kg) was used as the adhesive layer.Hydrogenated C5 hydrocarbon resin, softening temperature 110 A specimen was prepared in the same manner as in Comparative Example 1, except that 20 wt% was used. Physical properties were measured and the results are shown in Table 2 below.

Comparative Example 7

As adhesive layer, ethylene-vinylacetate resin containing 12% by weight of vinyl acetate and melt index of 3g / 10min (190 ℃, 2.16kg) was used.Adhesive aid (Hydrogenated C5 hydrocarbon resin, softening temperature 110 ℃, specific gravity 1.0) Except for using 15% by weight) to prepare a film specimen in the same manner as in Comparative Example 1. Physical properties were measured and the results are shown in Table 2 below.

Comparative Example 8

As a base layer, a block-co-polypropylene (hereinafter referred to as Block-PP) containing a melt index (Melt Index) of 10 g / 10 minutes (230 ° C., 2.16 Kg) and 5% by weight of ethylene was used. For example, 90% by weight of ethylene-vinylacetate resin (EVA) containing 8% by weight of vinyl acetate and a melt index of 3g / 10 minutes (190 ° C, 2.16kg) was used, and an adhesive aid (Hydrogenated C5 hydrocarbon resin, softening temperature) was used. 110 ° C, specific gravity 1.0) to prepare a film specimen using 10% by weight. Physical properties were measured and the results are shown in Table 2 below.

[Table 1] Raw material composition, thickness and thickness of each layer for Examples and Comparative Examples

[Table 2] Evaluation of physical properties of the film

From the results of Table 2, the protective film prepared according to the present invention is excellent in film forming processability and fish eye, and also excellent in adhesion, cutting property and no-curl property as compared with the comparative example, It was found that a protective film having a small change in adhesion could be obtained.

Claims (7)

Co-extruded and laminated a pressure-sensitive adhesive layer comprising a polypropylene-based resin and a vinyl acetate-based resin containing 9 to 18% by weight of vinyl acetate units on one or both sides of the base film, the adhesive layer is hydrogenated Protective film containing 0.5 to 5% by weight of a hydrocarbon (Hydrogenated hydrocarbon resin) adhesive aid. The method of claim 1, The polypropylene resin has a melt index (Melt Index, 230 ℃, 2.16Kg) is 3 ~ 9g / 10 minutes protective film. The method of claim 1, The vinyl acetate-based resin has a melt index (Melt Index, 190 ℃, 2.16Kg) is 1 ~ 7g / 10 minutes. The method of claim 1, The adhesive aid is a protective film using a softening temperature of 85 ~ 130 ℃, specific gravity of 0.8 ~ 1.2. The method according to any one of claims 1 to 4, The overall thickness of the protective film is a protective film of 20 ~ 60 ㎛. The method of claim 5, The thickness ratio of the base film and the adhesive layer is a 11: 1 to 1: 1 protective film. The method of claim 6, The base film is a protective film of 1 ~ 5g / 25mm adhesive strength measured by the JIS Z0237 method.