Release protection film and method for producing same

Abstract

To provide a mold release protective film and a method for producing the same.SOLUTION: A method for producing a mold release protective film includes: preparing a resin material; forming the resin material into a resin film layer through a rolling step and a stretching step; and using an embossing wheel to form an embossed pattern having a depth of 1 μm to 5 μm in the resin film layer to produce the mold release protective film. The resin material includes a polyolefin material and a petroleum resin. Based on 100 pts.wt. of the polyolefin material, an amount of the petroleum resin added is 5 pts.wt. to 20 pts.wt..SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a release protective film and a manufacturing method thereof, and more particularly to a release protective film suitable for large displays and panels and a manufacturing method thereof. [Background technology]

[0002] Generally, in order to provide sufficient protection, the protective film needs to have a certain structural strength. Currently, the protective film on the market is mainly cast polypropylene (CPP) produced by extrusion or inflation molding.

[0003] However, the surface of cast polypropylene film produced by extrusion or inflation molding is smooth, so it has a high peel strength, which makes it difficult to use when used as a protective film because the cast polypropylene film cannot be easily separated from the monitor or panel.

[0004] Therefore, in the conventional technology, a release layer is formed on the surface of the cast polypropylene film to increase the roughness of the protective film surface. This reduces the peeling force between the protective film and the monitor or panel. After use, the protective film can be easily separated from the monitor or panel. However, from the perspective of the overall manufacturing process, the coating and processing process makes the process complicated, and the use of solvents is not environmentally friendly.

[0005] In addition, with the advancement of technology, the size of monitors and panels continues to expand. In the case of large displays and panels (40 inches to 100 inches), the protective film is required to have good adhesion in order to exert a protective effect when combined with the display or panel. Furthermore, the protective film needs to have low peeling force properties so that the protective film can be peeled off from the display or panel.

[0006] Therefore, in order to meet the requirements of commercially available large displays and panels, it is an important challenge for this project to achieve both good adhesion and low peel force in the protective film by improving the material design and manufacturing method. Summary of the Invention [Problem to be solved by the invention]

[0007] The technical problem to be solved by the present invention is to provide a release protective film and a manufacturing method thereof in response to the shortcomings of the prior art. [Means for solving the problem]

[0008] In order to solve the above technical problems, one technical means adopted by the present invention provides a method for producing a release protective film. The method for producing a release protective film includes preparing a resin material, forming the resin material into a resin film layer through a rolling step and a stretching step, and using an embossing wheel to form an embossed pattern with a depth of 1 μm to 5 μm in the resin film layer to produce a release protective film. Here, the resin material includes a polyolefin material and a petroleum resin, and based on 100 parts by weight of the polyolefin material, the amount of the petroleum resin added is 5 parts by weight to 20 parts by weight.

[0009] In one embodiment, the release protective film is manufactured in a continuous process so as to be integrally molded.

[0010] In one embodiment, the petroleum resin is a hydrogenated petroleum resin.

[0011] In one embodiment, the petroleum resin is a hydrogenated petroleum resin polymerized with a monomer having 5 carbon atoms, or a hydrogenated petroleum resin polymerized with a monomer having 9 carbon atoms.

[0012] In one embodiment, the polyolefin material comprises 15% to 65% by weight of a propylene polymer and 35% to 85% by weight of an ethylene polymer, where the total weight of the polyolefin material is 100% by weight.

[0013] In one embodiment, the polyolefin material comprises 50% to 70% by weight of a propylene polymer, 10% to 30% by weight of an ethylene polymer, and 10% to 25% by weight of an ethylene vinyl acetate copolymer, where the total weight of the polyolefin material is 100% by weight.

[0014] In one embodiment, the stretching ratio in the stretching step of the resin material is 3.5 to 4.5.

[0015] In one embodiment, the depth of the embossed pattern in the resin film layer is 1 μm to 3 μm.

[0016] In order to solve the above technical problems, another technical means adopted by the present invention provides a release protective film manufactured by the above manufacturing method, and the peel strength of the release protective film on the glass surface is 130g / 25mm to 200g / 25mm.

[0017] In one embodiment, the haze value of the release protective film is less than 5.2%. Effect of the Invention

[0018] As an advantageous effect of the present invention, the release protective film and its manufacturing method according to the present invention have the technical features that "the amount of petroleum resin added is 5 to 20 parts by weight" and "an embossing pattern having a depth of 1 μm to 5 μm is formed in the resin film layer using an embossing wheel", so that the release protective film can be easily attached to a glass surface and has an appropriate peel strength with the glass surface, thereby overcoming the problem that conventional protective films cannot be manufactured in a simple process while having the characteristics of high structural strength and low peel strength. [Brief description of the drawings]

[0019] [Figure 1] 2 is a flowchart of a method for producing a release protection film according to an embodiment of the present invention. [Diagram 2] 1 is a schematic diagram of a release protective film according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] In order to better understand the features and technical contents of the present invention, please refer to the following detailed description of the present invention and the accompanying drawings, which are provided for reference and explanation only and are not intended to limit the scope of the present invention.

[0021] Hereinafter, the "release protective film and its manufacturing method" according to the embodiment of the present invention will be described by way of certain specific embodiments, and those skilled in the art can understand the advantages and effects of the present invention based on the contents disclosed in this specification. The present invention can be implemented or applied by other different specific embodiments, and various modifications and changes can be made to each detail in this specification based on different perspectives and applications without departing from the concept of the present invention. In addition, as described in advance, the accompanying drawings of the present invention are simple schematic illustrations and are not drawn based on actual size. The technical contents of the present invention will be described in more detail based on the following embodiments, but the disclosure does not limit the scope of protection of the present invention. In addition, the term "or" used in this specification may include any one or more combinations of the related items listed according to the actual situation.

[0022] In order to solve the problem that the manufacturing process of the conventional protective film is complicated and cannot achieve both high structural strength and low peeling force, the present invention makes improvements to the materials and manufacturing methods of the protective film, so that the protective film can be applied to large displays and panels in the optoelectronics industry.

[0023] In the present invention, an embossed pattern is formed on the surface of the release protective film by using an embossing wheel, which reduces the peeling force of the release protective film on the glass surface. In addition, since the release protective film of the present invention is integrally molded, the release protective film itself has releasability that allows it to be easily peeled off, so there is no need to install a release layer through a coating process or a lamination process. In addition, the release protective film of the present invention has the advantage that it is manufactured by a continuous process and the process is simple.

[0024] The present invention uses specific materials to produce a release protective film, which has the properties of high structural strength and low haze value.

[0025] By selecting a specific material, the present invention improves the adhesive strength of the release protective film on the glass surface. Thus, on the premise that the release protective film is easily peeled off, there is excellent adhesive strength between the release protective film and a monitor or panel. That is, the release protective film according to the present invention has good adhesiveness to a large-area glass substrate, and is therefore applicable to large (40-100 inch) monitors and panels.

[0026] As shown in FIG. 1, the method for producing a release protective film according to the present invention includes preparing a resin material (step S1), forming the resin material into a resin film layer by a rolling step and a stretching step (step S2), and producing a release protective film using an embossing wheel (step S3).

[0027] In step S1, the resin material includes a polyolefin material and a petroleum resin. The polyolefin material is the main component of the release protection film. For example, the content of the polyolefin is more than 70 wt%.

[0028] In one embodiment, the polyolefin material comprises at least propylene polymer and ethylene polymer. The addition of petroleum resin can improve the peeling force of the release protective film on the glass surface and reduce the haze value of the resin material. For practical products, the haze value of the release protective film is preferably less than 5.2%.

[0029] Experiments have shown that if the amount of petroleum resin added is too high, the viscosity of the resin material will be too high, which is unfavorable for production, and if the amount of petroleum resin added is too low, the peeling force of the release protective film on the glass surface will be low.

[0030] Specifically, the amount of the petroleum resin added is 5 parts by weight to 20 parts by weight based on 100 parts by weight of the polyolefin material, and may be, for example, 6 parts by weight, 8 parts by weight, 10 parts by weight, 12 parts by weight, 14 parts by weight, 16 parts by weight, or 18 parts by weight.

[0031] In one embodiment, the petroleum resin is a hydrogenated petroleum resin. Specifically, the petroleum resin is a hydrogenated petroleum resin polymerized with a monomer having 5 carbon atoms, or a hydrogenated petroleum resin polymerized with a monomer having 9 carbon atoms.

[0032] For example, the petroleum resin may be, for example, a piperylene hydrogenated resin or a dicyclopentadiene (DCPD) hydrogenated resin, or may be an aqueous white thermoplastic resin obtained by polymerizing and hydrogenating a C9 fraction, which is a by-product of ethylene decomposition, but the present invention is not limited thereto.

[0033] The choice of polyolefin material also influences the peel force of the protective film to the glass surface, hi one exemplary embodiment, the polyolefin material includes a propylene polymer and an ethylene polymer.

[0034] The propylene polymer may be a propylene random polymer, a copolymer polypropylene (polymerized with propylene and ethylene monomers), a terpolymer polypropylene (polymerized with propylene, ethylene, and butene monomers), or a propylene block copolymer.

[0035] In one preferred embodiment, the polyolefin material may be propylene random polymer. Propylene random polymer has relatively low crystallinity, improves the effect of forming embossed pattern and improves the ventilation effect of the film surface, thereby preventing the formation of bubbles on the release protective film and the glass surface.

[0036] Specifically, the melting point of the propylene random polymer is 140° C. to 150° C., and preferably 142° C. to 146° C. The melt index of the propylene random polymer is 2 to 5, and preferably 2 to 4.

[0037] In one preferred embodiment, the ethylene polymer may be a linear low-density polyethylene. Specifically, the melt index of the linear low-density polyethylene is 2 to 5, and preferably 2 to 4.

[0038] The present invention controls the blending ratio of propylene polymer and ethylene polymer so as to adjust the flexibility of the polyolefin material. The polyolefin material contains 15% to 65% by weight of propylene polymer and 35% to 85% by weight of ethylene polymer, where the total weight of the polyolefin material is 100% by weight.

[0039] For example, the propylene polymer content may be 20%, 30%, 40%, 50% or 60% by weight, and the ethylene polymer content may be 40%, 50%, 60%, 70% or 80% by weight.

[0040] In addition to propylene and ethylene polymers, the polyolefin materials may further include ethylene vinyl acetate copolymers.

[0041] The addition of ethylene vinyl acetate copolymer improves the excellent adhesion between the release protective film and the monitor or panel under the premise that the release protective film can be easily peeled off, so that the release protective film is suitable for large monitors or panels.

[0042] However, the content of ethylene vinyl acetate copolymer needs to be controlled within a certain range.If the content of ethylene vinyl acetate copolymer is too high, the viscosity of the resin material is too high, which is disadvantageous for production.If the content of ethylene vinyl acetate copolymer is too low, the adhesive strength of the release protective film on the glass surface is low, and the release protective film cannot be well attached to the glass surface.

[0043] Therefore, the compounding ratio of the propylene polymer, the ethylene polymer, and the ethylene-vinyl acetate copolymer is controlled to adjust the properties of the polyolefin material. The polyolefin material contains 50% to 70% by weight of the propylene polymer, 10% to 30% by weight of the ethylene polymer, and 10% to 25% by weight of the ethylene-vinyl acetate copolymer, with the total weight of the polyolefin being 100% by weight. In one preferred embodiment, the content of the ethylene-vinyl acetate copolymer is 15% to 20% by weight, with the total weight of the polyolefin being 100% by weight.

[0044] By selecting the above materials, the release protective film of the present invention has good lamination property and suitable peeling force, and can be applied to large displays and panels, especially in the optoelectronics industry.

[0045] In the rolling step of process S2, the temperature of the screw is controlled to 170° C. to 240° C. so as to roll the resin material.

[0046] In the stretching step of step S2, the resin material is stretched at a temperature of 100°C to 160°C at a stretch ratio of 3 to 5 times to form a resin film layer. Preferably, in the stretching step, the resin material is stretched at a stretch ratio of 3.5 to 4.5 times. The most preferred stretch ratio for the resin material is 4 times. For example, when the stretch ratio is 5 times, the rigidity of the resin film layer increases, but the adhesive strength between the resin film layer and the glass surface decreases.

[0047] In step S3, an embossing pattern having a depth of 1 μm to 5 μm is formed in the resin film layer by using an embossing wheel to produce a release protective film. Preferably, the depth of the embossing pattern in the resin film layer is 1 μm to 3 μm.

[0048] In one exemplary embodiment, the pattern on the embossing wheel is a diamond shape, and the depth of the diamond shape is between 0.5mm and 1.5mm, preferably between 0.75mm and 1.25mm.

[0049] Specifically, the steps S1 to S3 are completed in a continuous process. Therefore, the method for producing a release protective film according to the present invention has the advantage that the process is simple. In addition, the produced release protective film is integrally molded.

[0050] As shown in Fig. 2, an embossed pattern 11 is formed on the bonding surface 10 of the release protective film 1. The groove pattern of the embossed pattern 11 corresponds to the convex pattern of the embossing wheel. In this way, by reducing the contact surface area when the release protective film is placed on the glass substrate, the effect of reducing the peeling force of the release protective film on the glass substrate can be achieved.

[0051] In addition, the depth of the embossed pattern of the resin film layer can be adjusted to control the peeling force between the release protective film and the glass substrate. The embossed pattern is preferably a diamond embossed pattern, but the present invention is not limited thereto. Other quadrilateral embossed patterns are also acceptable. EXAMPLES

[0052] [Examples 1 to 4] In order to prove that the release protective film of the present invention can be attached to a glass surface and has an appropriate peel strength, propylene random polymer and low density polyethylene were used as polyolefin materials based on the above steps S1 to S3, and a resin material was prepared by mixing hydrogenated petroleum resin and the polyolefin material.

[0053] The resin material was formed into a resin film layer through a rolling step and a stretching step. The resin film layer was formed into an embossed pattern on the surface of the resin film layer by an embossing wheel, thereby obtaining the release protective films according to Examples 1 to 4. The thicknesses of the release protective films according to Examples 1 to 4 were 100 μm to 150 μm. However, the thickness of the release protective film is not limited to this, and the thickness can be adjusted to match the size of a monitor or panel.

[0054] Next, the haze value and peeling force of the release protective film were measured to evaluate the adhesion of the release protective film to the glass substrate. The contents of the specific components of the resin material, the stretching ratio in the stretching step, the depth of the embossed pattern, and the evaluation of the properties of the release protective film are shown in Table 1.

[0055] The haze value of the release protective film was measured based on ASTM D1003 (CIE C) specified by the American Society for Testing and Materials (ASTM).

[0056] In measuring the peeling force, a roller weighing 4.5 pounds was used to roll the release protective film back and forth once on the glass surface to attach the release protective film to the glass. Then, the glass was fixed to the lower clamp, the release protective film was folded and fixed to the upper clamp, and the release protective film and the glass were peeled off in opposite directions at 180 degrees at a speed of 30 mm / min, and the average value of the peeling force in this process was taken as the peeling force.

[0057] Regarding the evaluation of adhesion, the adhesion of the release protective film to the glass surface was divided into three levels. In Table 1, if the release protective film was easily adhered to the glass substrate, it was indicated as "good." If the release protective film was easily adhered to the glass substrate but was prone to wrinkling or had uneven adhesion, it was indicated as "fair." If the release protective film was difficult to adhere to the glass substrate, it was indicated as "poor."

[0058] [Examples 5 to 6] The release protective films according to Examples 5 to 6 are similar to the release protective films according to Examples 1 to 4. As for the difference between them, in Examples 5 to 6, in addition to the propylene polymer and the low-density polyethylene, the polyolefin material further contains an ethylene-vinyl acetate copolymer.

[0059] After preparing a resin material based on the content of the components shown in Table 1, the resin material was formed into a resin film layer through a rolling step and a stretching step. The resin film layer was further formed with an embossing wheel to form an embossed pattern on the surface of the resin film layer, thereby producing a release protective film. Similarly, the haze value and peeling force of the release protective film were measured to evaluate the adhesion of the release protective film to the glass substrate. The specific component contents of the resin material, the stretching ratio in the stretching step, the depth of the embossed pattern, and the evaluation of the properties of the release protective film are as shown in Table 1.

[0060] [Comparative Example 1] The release protective film according to Comparative Example 1 is similar to the release protective film according to Example 1. The differences between them are that no hydrogenated petroleum resin was added to Comparative Example 1, and no embossed pattern was formed on the surface of the release protective film.

[0061] After preparing a resin material based on the content of the components shown in Table 1, the resin material was formed into a resin film layer through a rolling step and a stretching step. The resin film layer was directly manufactured into a release protective film without processing with an embossing wheel. Similarly, the haze value and peeling force of the release protective film were measured to evaluate the adhesion of the release protective film to the glass substrate. The specific component contents of the resin material, the stretching ratio in the stretching step, the depth of the embossed pattern, and the evaluation of the properties of the release protective film are as shown in Table 1.

[0062] [Comparative Example 2] The release protective film according to Comparative Example 2 is similar to the release protective film according to Example 1. The difference between them is that in Comparative Example 1, no hydrogenated petroleum resin was added.

[0063] After preparing a resin material based on the content of the components shown in Table 1, the resin material was formed into a resin film layer through a rolling step and a stretching step. The resin film layer was produced as a release protective film by forming an embossed pattern on the surface of the resin film layer using an embossing wheel. Similarly, the haze value and peeling force of the release protective film were measured to evaluate the adhesion of the release protective film to the glass substrate. The specific component contents of the resin material, the stretching ratio in the stretching step, the depth of the embossed pattern, and the evaluation of the properties of the release protective film are as shown in Table 1.

[0064] [Table 1]

[0065] According to the results in Table 1, the release protective film according to the present invention has an appropriate peel strength (120g / 25mm to 200g / 25mm), and can be smoothly attached to a glass substrate and easily peeled off. To be more specific, the peel strength of the release protective film exceeds 120g / 25mm. In addition, in order to be easily peeled off, the peel strength of the release protective film needs to be lower than 200g / 25mm.

[0066] In addition, according to the results of Examples 5 and 6, when the polyolefin material simultaneously contains a propylene polymer, an ethylene polymer, and an ethylene vinyl acetate copolymer, the peeling force of the release protective film is 150g / 25mm to 200g / 25mm. Thus, the release protective film according to the present invention can be applied to large displays and panels (40 inches to 100 inches).

[0067] According to the results in Table 1, the addition of petroleum resin can improve the peel strength of the release protective film on the glass surface to a value exceeding 120g / 25mm, and even exceeding 145g / 25mm in some cases. In addition, the addition of petroleum resin can reduce the haze value of the resin material to less than 5.2%.

[0068] According to the results of Examples 1 and 2, if the stretching ratio is too high, it leads to a decrease in the peeling strength of the release protective film. According to experiments, the stretching ratio is preferably 3 to 5 times, and thereby the peeling strength of the release protective film on the glass surface exceeds 145 g / 25 mm.

[0069] According to the results of Examples 1, 3 and 4, the compounding ratio of the polyolefin material affects the haze value and peeling force of the release protective film, and can be appropriately adjusted within the content range.

[0070] The depth of the embossed pattern also affects the peeling force of the release protective film, according to the results of Examples 5 and 6. Experiments have shown that the depth of the embossed pattern is preferably 1 μm to 3 μm.

[0071] It is particularly noteworthy that the release protective film of the present invention is manufactured in a continuous process so as to be integrally molded, and furthermore, since there is no need to apply a release layer to the surface of the release protective film by coating or lamination, the manufacturing process is simple and has the advantage of being environmentally friendly.

[0072] [Advantageous Effects of the Embodiments] As an advantageous effect of the present invention, the release protective film and its manufacturing method according to the present invention have the technical features that "the amount of petroleum resin added is 5 to 20 parts by weight" and "an embossing pattern having a depth of 1 μm to 5 μm is formed in the resin film layer using an embossing wheel", so that the release protective film can be easily attached to a glass surface and has an appropriate peel strength with the glass surface, thereby overcoming the problem that conventional protective films cannot be manufactured in a simple process while having the characteristics of high structural strength and low peel strength.

[0073] To explain further, the components of polyolefin material also affect the peeling force of the release protective film.When polyolefin material contains propylene polymer, ethylene polymer and ethylene vinyl acetate copolymer at the same time, under the premise that the release protective film is easily peeled off, it has excellent peeling force between the release protective film and the monitor or panel.Therefore, the release protective film is suitable for large displays or panels.

[0074] In addition, the content ratio of propylene polymer, ethylene polymer and ethylene vinyl acetate copolymer also affects the peeling force of the release protective film.If the content of ethylene vinyl acetate copolymer is too high, the viscosity of the resin material is too high, which is disadvantageous for production.If the content of ethylene vinyl acetate copolymer is too low, the peeling force of the release protective film on the glass surface is low, and the release protective film cannot be well attached to the glass surface.

[0075] The above disclosure is merely a preferred embodiment of the present invention, and the scope of the claims of the present invention is not limited thereto. Therefore, all equivalent technical modifications made by utilizing the specification and drawings of the present invention are included in the scope of the claims of the present invention. [Explanation of symbols]

[0076] 1...Release protection film 10... Bonding surface 11...Embossed pattern

Claims

1. Preparing a resin material comprising a polyolefin material and a petroleum resin; The resin material is formed into a resin film layer by a rolling step and a stretching step; and forming an embossed pattern having a depth of 1 μm to 5 μm in the resin film layer using an embossing wheel to produce a release protective film. The amount of the petroleum resin added is 5 parts by weight to 20 parts by weight based on 100 parts by weight of the polyolefin material; A method for producing a release protective film, characterized in that the polyolefin material contains 50% by weight to 70% by weight of a propylene polymer, 10% by weight to 30% by weight of an ethylene polymer, and 10% by weight to 25% by weight of an ethylene-vinyl acetate copolymer, where the total weight of the polyolefin material is 100% by weight.

2. The method for producing a release protective film according to claim 1 , wherein the release protective film is produced in a continuous process so as to be integrally molded.

3. The method for producing a release protective film according to claim 1 , wherein the petroleum resin is a hydrogenated petroleum resin.

4. The method for producing a release protective film according to claim 3 , wherein the petroleum resin is a hydrogenated petroleum resin polymerized with a monomer having 5 carbon atoms, or a hydrogenated petroleum resin polymerized with a monomer having 9 carbon atoms.

5. The method for producing a release protective film according to claim 1, wherein the content of the ethylene-vinyl acetate copolymer is 15% by weight to 20% by weight, based on the total weight of the polyolefin material being 100% by weight.

6. The method for producing a release protection film according to claim 1, wherein the stretching ratio of the resin material in the stretching step is 3.5 to 4.

5.

7. The method for producing a release protective film according to claim 1, wherein the depth of the embossed pattern in the resin film layer is 1 μm to 3 μm.

8. A release protective film produced by the method for producing a release protective film according to any one of claims 1 to 7, characterized in that the peel strength of the release protective film on a glass surface is 130 g / 25 mm to 200 g / 25 mm.

9. The release protective film according to claim 8 , wherein the haze value of the release protective film is less than 5.2%.

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