KR100969953B1 - A preparing method of thermoplastic polyurethane(TPU) composite for increasing bonding strength of TPU film - Google Patents

Abstract

The present invention relates to a method for preparing a composition for thermoplastic polyurethane (TPU) film with improved adhesive properties, and more particularly, a modified masterbatch in pellet form containing silica and a polar polymer in a thermoplastic polyurethane (TPU) resin separately. To prepare a composition in the form of pellets by mixing and melting on a thermoplastic polyurethane (TPU) substrate, while maintaining an elastic force compared to the conventional thermoplastic polyurethane (TPU), the adhesive strength is excellent, and manufacturing a thin thermoplastic polyurethane film In addition, the pinhole phenomenon does not occur, it can replace the expensive imported goods, and unlike the conventional working method of bonding through the cleaning and pretreatment process by volatile toxic solvent to reduce the adhesion failure rate of the film According to the composition for thermoplastic polyurethane film according to Since no solvent is used at all, it can bring about an environmentally friendly improvement of the workplace.

In addition, in the method of manufacturing a composition for thermoplastic polyurethane film, it is a processing method using a modified masterbatch, not a method of adding an adhesion improving material in synthesizing a thermoplastic polyurethane to improve adhesive strength in the related art, so that it can be applied to a small workplace. Regardless of the type of thermoplastic polyurethane used, the present invention can be applied to various fields by changing only the thermoplastic polyurethane substrate as needed during the production of the modified masterbatch.

Thermoplastic Polyurethane, Silica, Dry Silica, Wet Silica, Polar Polymer, Modified Masterbatch, Adhesion

Description

A method for producing a composition for thermoplastic polyurethane film having excellent adhesion {A preparing method of thermoplastic polyurethane (TPU) composite for increasing bonding strength of TPU film}

The present invention separately prepares a modified masterbatch in the form of pellets containing silica and a polar polymer in a thermoplastic polyurethane (TPU) resin, mixed with the thermoplastic polyurethane (TPU) substrate to prepare a composition in the form of pellets, It relates to a method for producing a composition for thermoplastic polyurethane (TPU) film having excellent adhesion, characterized in that the adhesive strength is excellent while maintaining the elastic force as compared to the thermoplastic polyurethane.

Today, due to the remarkable development of the domestic IT industry, mobile phone and computer related equipment have been steadily developing. These devices have made a lot of advances in terms of hardware with the development of software, but the development of parts of the hardware that can make up for the shortcomings of the body products is almost stale, so it is dependent on imported goods.

In particular, the material sector is not pursuing R & D and using products processed with almost imported raw materials, and is simply pursuing corporate profits. It is true.

In addition, the focus is on the physical properties of the product. Especially in the assembly process, many solvents, such as toluene and methyl ethyl ketone (MEK), are toxic to humans. Because of the assembly work, there are many causes of industrial accidents.

In particular, since the thermoplastic polyurethane film used as the keypad of the electronic component is a chemical material that is difficult to bond during assembly, there is a problem that adhesion is performed after treating the surface with a solvent through surface cleaning or pretreatment. In order to solve such a problem, the research has been conducted at various angles over the years, but the problem of discoloration of the thermoplastic polyurethane film and the improvement of adhesive strength have not been solved.

In addition, the thermoplastic polyurethane film currently used has a number of problems, such as gelation on the surface of the film when the high hardness resin is used, discoloration when used at high temperatures. On the other hand, the low hardness film has a disadvantage in that it is difficult to use due to the problem that heat shrinkage occurs badly. Since this problem is a problem that occurs in domestic thermoplastic polyurethane films, most consumers are using imported products.

Accordingly, the present inventors have made efforts to solve the above problems of adhesion of the thermoplastic polyurethane film, and as a result, after mixing the silica and the polar polymer in the thermoplastic polyurethane substrate to make a modified masterbatch, it is first applied to the thermoplastic polyurethane substrate. The present invention can be achieved by solving the above problems by melting and dispersing a composition for thermoplastic polyurethane film in a new form.

Therefore, in order to solve the above problems, the present invention prepares a modified masterbatch in a pellet form by mixing a thermoplastic polyurethane substrate, silica and a polar polymer in advance, and melts the mixture using a twin screw extruder. It is an object of the present invention to provide a method for producing a composition for thermoplastic polyurethane film having excellent adhesion, characterized in that the adhesion can be greatly improved without the occurrence of the pinhole phenomenon, which is conventionally produced during film production. .

In addition, the present invention, in the method for producing a composition for thermoplastic polyurethane film, in contrast to the conventional method of adding an adhesion improving material during the synthesis of thermoplastic polyurethane in order to improve the adhesive force, adopting a post-processing method using a modified master batch. Regardless of the type of thermoplastic polyurethane material used, it is easy to apply to a variety of fields by simply changing the base material during the production of the masterbatch. As a resin to be used, a thermoplastic polyurethane substrate, a silica, and a polar polymer are mixed to produce a pellet, so that the silica and the polar polymer compound may be uniformly dispersed in the composition to improve the quality when preparing the thermoplastic polyurethane film composition. One thing special Another object is to provide a method for producing a composition for thermoplastic polyurethane film having excellent adhesive strength.

Therefore, the film produced by the composition for thermoplastic polyurethane film having excellent adhesion according to the present invention has excellent adhesion when used in electronic parts and the like, unlike conventional work methods, in order to reduce adhesion failure rate such as toluene and methyl ethyl ketone, such as toxicity. It is another object of the present invention to provide a method for preparing a composition for thermoplastic polyurethane film having excellent adhesive strength, which is environmentally-friendly, having an effect of improving the working environment since it does not undergo washing and pretreatment by using a solvent.

The present invention for solving the above problems is 10 to 20 parts by weight of the modified masterbatch mixed with respect to 90 parts by weight of the thermoplastic polyurethane substrate,
The temperature of the die is maintained at 130 ~ 180 ℃, the screw speed is 45 to 60rpm melted in a twin-screw extruder to produce in the form of pellets excellent thermoplasticity, characterized in that the manufacturing method of the composition for thermoplastic polyurethane film excellent It is a solution.
However, the modified masterbatch is mixed with 100 parts by weight of the thermoplastic polyurethane substrate, 1 to 3 parts by weight of silica and 10 to 30 parts by weight of the polar polymer to maintain the die temperature of 130 ~ 180 ℃, screw speed 45 ~ 60rpm It is preferable to use what is manufactured in pellet form by melting in a twin screw extruder.
And the thermoplastic polyurethane base material uses a hardness of 87 ~ 95A,

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The silica is dry silica using dry surface-treated silica having a BET specific surface area of 175 to 350 m 2 / g, an average particle diameter of 7 to 12 nm, and a pH of 3.7 to 4.7, or as a wet silica, a BET specific surface area of 240 to 340 Using wet surface-treated silica having a m 2 / g, CTAB specific surface area of 140 to 170 m 2 / g, specific gravity of 1.95 to 2.05, and a pH of 6.5 to 7.5,

The polar polymer is preferably used by selecting one or more of ethylene vinyl acetate (EVA), ethylene butyl acrylate (EBA), ethylene methyl acrylate (EMA), and ethylene ethyl acrylate (EEA).

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According to the present invention by the above-mentioned means for solving the problem, the modified masterbatch is mixed with a thermoplastic polyurethane substrate to produce a pellet form, and then manufactured as a film for keypads and subjected to the adhesion test, the adhesive strength of about 20% or more compared to the existing product In addition, the pinhole phenomenon that occurs during the manufacture of a thin thermoplastic polyurethane film does not occur, and thus, a compound for thermoplastic polyurethane film which can replace an expensive imported product can be manufactured.

In order to reduce the adhesion failure rate in the past, the adhesive and the pre-treatment process using a toxic solvent, but the adhesive for thermoplastic polyurethane film composition excellent in the adhesive force according to the present invention does not use a volatile organic solvent at all because the workplace is environmentally friendly It can have an effect that can be improved.

On the other hand, in the method of manufacturing a composition for thermoplastic polyurethane film, it is a processing method using a modified masterbatch, not a method of adding an adhesive improving material at the time of synthesizing thermoplastic polyurethane in order to improve the adhesive force, so that it can be applied even in a small workplace. It has advantages. In addition, irrespective of the type of thermoplastic polyurethane used, the present invention can be applied to various fields by changing only the thermoplastic polyurethane base material as needed in manufacturing a modified masterbatch.

According to the feature of the method for producing a composition for thermoplastic polyurethane film having excellent adhesion according to the present invention for achieving the above effect, the present invention is made from polyester or polyether polyol, organic diisocyanate and chain extender (diols). Melting various types of modified masterbatches based on the prepared thermoplastic polyurethane (specified for the production method of various types of thermoplastic polyurethane elastomers in Korean Patent Application Laid-Open No. 2000-0017500, 2007-0023558, etc.) Characterized by a method for producing a composition for thermoplastic polyurethane film having excellent adhesion, including the step of mixing.

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

The composition for thermoplastic polyurethane (TPU) film according to the present invention is composed of a thermoplastic polyurethane substrate and an improving agent for improving the physical properties of the substrate.

As the improving agent, a modified masterbatch prepared by mixing a thermoplastic polyurethane substrate, a silica and a polar polymer is mixed with the thermoplastic polyurethane substrate.

In the present invention, the composition for film prepared by mixing the modified masterbatch on the thermoplastic polyurethane substrate is as follows.

In the composition for thermoplastic polyurethane films,

10 to 20 parts by weight of the modified masterbatch based on 90 parts by weight of the thermoplastic polyurethane substrate,

The modified masterbatch relates to a composition for thermoplastic polyurethane film having excellent adhesion, comprising 100 parts by weight of a thermoplastic polyurethane substrate, 1 to 3 parts by weight of silica, and 10 to 30 parts by weight of a polar polymer.

The composition for a thermoplastic polyurethane film according to the present invention (hereinafter referred to as a 'film composition') is classified into an improving agent for improving physical properties of the thermoplastic polyurethane substrate and the substrate.

First, the thermoplastic polyurethane substrate as a component of the present invention will be described in detail as follows.

Thermoplastic polyurethanes (TPU) as substrate components in the present invention are conventional thermoplastic polyurethanes (TPU) made from linear polyols, typically polyester or polyether polyols, organic diisocyanates and short-chain diols (chain extenders). Is used as the substrate.

And it is preferable that the thermoplastic polyurethane (TPU) which is a base material used by this invention is 87-95A of hardness. When the hardness of the thermoplastic polyurethane (TPU) is less than 87A or more than 95A, it is possible to use it as a general film, but it cannot be used for the keypad, and in the case of high hardness, the melting point is high, which makes processing difficult.

And it will be described in detail with respect to the modified master batch used as an improving agent of the present invention.

In the present invention, as the silica serves to improve the corrosion resistance and chemical resistance of the thermoplastic polyurethane elastomer, it is preferable to use dry silica or wet silica, more preferably to use a surface-treated silica. The dry surface-treated silica has a BET specific surface area of 175 to 350 m 2 / g, an average particle diameter of 7 to 12 nm, a pH of 3.7 to 4.7, and a wet surface treated silica with a BET specific surface area of 240 to 340 m 2 / g. It is preferable that it is CTAB specific surface area 140-170m <2> / g, specific gravity is 1.95-2.05 and pH is 6.5-7.5.

The type of silica should be selected differently according to the use of the film. Generally, when it is necessary to maintain the transparency of the film, it is preferable to use dry silica, and when the transparency of the film is not required, the dry silica is required. (Aerosil) or wet silica (Zeosil) may be used. However, since silica affects the physical properties of the film when it contains moisture, the silica must be mixed with a polyurethane substrate to prepare a modified masterbatch to remove water contained in the silica in a 120 ± 2 ° C convection oven. It should be used after drying for more than 2 hours.

In the present invention, the amount of silica used as the reforming masterbatch is preferably 1 to 3 parts by weight. If the amount of the silica is mixed less than the range defined above, the corrosion resistance and the chemical resistance may decrease due to the lack of the amount of the silica, and if the amount of the silica is used exceeds the range defined above, There is a concern that the problem of difficulty in processing and the increase in hardness due to the excessive amount may occur.

In addition, the polar polymer used as the modified masterbatch in the present invention serves to improve the adhesive force of the thermoplastic polyurethane composition, and the amount of the polar polymer is preferably 10 to 30 parts by weight. If the blending amount of the polar polymer is less than the range defined above, there is a possibility that the adhesive force may be lowered due to the addition amount of the polar polymer. If the blending amount of the polar polymer exceeds the range defined above, the addition amount of the polar polymer is excessive. The workability decreases due to the adhesiveness, and there is a concern that the adhesiveness may appear even when the film is produced.

The polar polymer that can be used in the present invention is a polar polymer is one of resins such as ethylene vinyl acetate (EVA), ethylene butyl acrylate (EBA), ethylene methyl acrylate (EMA), ethylene ethyl acrylate (EEA), or It is preferable to select and use more than that.

On the other hand, in the film composition of the present invention, it is preferable to mix the mixing ratio of silica and the polar polymer in a ratio of 10 to 1 to improve adhesion.

In addition, the mixing amount of the modified master batch is preferably mixed 10 to 20 parts by weight with respect to 90 parts by weight of the thermoplastic polyurethane substrate. When the mixing amount of the modified master batch is less than 10 parts by weight, the adhesion, corrosion resistance, and chemical resistance may deteriorate due to insufficient content of silica and polar polymer, which are effective modifying ingredients, and the mixing amount of the modified master batch is 20 weight If the amount is exceeded, the hardness and physical properties may be lowered and migration of the additive may be caused.

In the present invention, the mixing amount of the modified masterbatch mixed on the thermoplastic polyurethane substrate is limited to the above range, but the mixing amount of the modified masterbatch on the basis of the total amount of the improving agent according to the content of the silica and the polar polymer, which is the improver contained in the modified masterbatch, is changed. May be adjusted as appropriate.

The reason for using the thermoplastic polyurethane as the resin used in the modified master batch in the present invention is that the silica and the polar polymer compound contained in the modified master batch during the preparation of the film composition are sufficiently uniformly dispersed in the film composition so that the film It is characterized by making the quality of the composition uniform so that the adhesion can be improved.

In addition, the film composition of the present invention is prepared by adding a small amount of UV stabilizers and other additives commonly used as needed to improve the adhesion, the use of the additive is not a feature of the present invention.

Hereinafter, the method for producing a composition for thermoplastic polyurethane (TPU) film having excellent adhesive strength according to the present invention will be described in detail.

The manufacturing method of the composition for thermoplastic polyurethane films excellent in the adhesive force of this invention is

10 to 20 parts by weight of the modified masterbatch is mixed with respect to 90 parts by weight of the thermoplastic polyurethane substrate,

The temperature of the die is maintained at 130 ~ 180 ℃, the screw speed is characterized in that it is produced in pellet form by melting in a twin screw extruder maintained at 45 ~ 60rpm.

The modified masterbatch is mixed with 100 parts by weight of the thermoplastic polyurethane substrate, 1 to 3 parts by weight of silica and 10 to 30 parts by weight of the polar polymer to maintain a die temperature of 130 to 180 ° C., and a screw speed of 45 to 60 rpm. It is melted in a retained twin screw extruder and used in the form of pellets.

The silica is dry silica using BET specific surface area of 175 to 350 m 2 / g, dry surface treated silica having an average particle diameter of 7 to 12 nm and pH of 3.7 to 4.7, or BET specific surface area of 240 to 240 as wet silica. It is preferable to use wet surface-treated silica having 340 m 2 / g, CTAB specific surface area of 140 to 170 m 2 / g, specific gravity of 1.95 to 2.05 and pH of 6.5 to 7.5.

The polar polymer may be selected from one or more of ethylene vinyl acetate (EVA), ethylene butyl acrylate (EBA), ethylene methyl acrylate (EMA), and ethylene ethyl acrylate (EEA).

In the process conditions of the twin screw extruder used in the preparation of the modified masterbatch and the composition for thermoplastic polyurethane film having excellent adhesion, the die temperature should be maintained at 130 to 180 ° C. for complete melting, and the screw speed for uniform dispersion. It is preferable to maintain 45 to 60 rpm, more preferably 45 to 55 rpm.

In the above case, when the die temperature is lower than 130 ° C., there is a fear that the complete melt mixing of the thermoplastic polyurethane substrate and the modifying component may not be performed in the twin screw extruder, and when the die temperature is higher than 180 ° C., Since the flowability rises sharply, there is a risk of difficulty in pelletizing.

And if the screw speed is less than 45rpm in the above, there is a fear that the productivity is lowered, if the screw speed exceeds 60rpm, because the melting characteristics of each mixture is different, complete dispersion is not achieved, so that the uneven masterbatch or There is a fear that a problem that the composition is produced. Therefore, the speed of the screw is most preferably maintained at 45 ~ 55rpm.

Therefore, the composition prepared by the above method has a merit that can be applied even in small-sized businesses because it is a processing method using a modified masterbatch, unlike the conventional method of adding an adhesive improving agent in synthesizing thermoplastic polyurethane to improve adhesive strength. And, regardless of the type of thermoplastic polyurethane used, there is an advantage in that it can be applied to various fields by simply changing the thermoplastic polyurethane substrate in the production of the master batch.

Hereinafter, the content of the present invention will be described in more detail with reference to Examples. And these examples are only presented to understand the content of the present invention, the present invention is not necessarily limited only to the following examples.

1. Preparation of the composition for thermoplastic polyurethane film

(Example 1)

90 parts by weight of the thermoplastic polyurethane substrate and 10 parts by weight of the modified masterbatch were mixed and melted at a temperature of 177 ± 2 ° C. through a twin screw extruder to prepare a composition for a thermoplastic polyurethane film in the form of a transparent pellet.

And wherein the modified masterbatch is mixed with 100 parts by weight of a thermoplastic polyurethane substrate, 10 parts by weight of a polar polymer and 1 part by weight of wet surface treated silica, followed by melt mixing through a twin screw extruder having a die temperature of 177 ± 2 ° C. to prepare a modified masterbatch. It was. At this time, the speed of the main screw was 50 ± 2rpm, the temperature of the first screw was set to room temperature for more efficient dispersion. In addition, the polymer used for water removal was used after drying for 2 hours in a convection oven at 120 ℃. Modified masterbatch for improving the adhesion prepared as described above was dried for 24 hours in an oven at 120 ℃ to remove the moisture inside.

(Example 2)

After mixing 90 parts by weight of the thermoplastic polyurethane substrate and 10 parts by weight of the modified masterbatch, the composition for thermoplastic polyurethane film in the form of a transparent pellet was prepared according to the method of Example 1.

The modified masterbatch was mixed with 100 parts by weight of a thermoplastic polyurethane substrate, 20 parts by weight of a polar polymer, and 2 parts by weight of wet surface treated silica, and then used to prepare a modified masterbatch according to the method of Example 1.

(Example 3)

After mixing 90 parts by weight of the thermoplastic polyurethane substrate and 10 parts by weight of the modified masterbatch, the composition for thermoplastic polyurethane film in the form of a transparent pellet was prepared according to the method of Example 1.

The modified masterbatch was mixed with 100 parts by weight of a thermoplastic polyurethane substrate, 30 parts by weight of a polar polymer, and 3 parts by weight of wet surface-treated silica, and then used to prepare a modified masterbatch according to the method of Example 1.

(Comparative Example 1)

Using 100 parts by weight of the thermoplastic polyurethane substrate, according to the method of Example 1, a composition for a thermoplastic polyurethane film in the form of a transparent pellet was prepared.

(Comparative Example 2)

Using 100 parts by weight of the thermoplastic polyurethane substrate and 0.5 part by weight of the wet surface-treated silica, a composition for a thermoplastic polyurethane film in the form of a transparent pellet was prepared according to the method of Example 1.

The composition components of the composition for thermoplastic polyurethane films prepared according to the methods of Examples 1 to 3 and Comparative Examples 1 and 2 are shown in Table 1 below.

                                                              (Unit: parts by weight) Ingredient Example Comparative example One 2 3 One 2 TPU ¹⁾ 100 90 90 100 100 Reform Masterbatch 10 ²⁾ 10 ³⁾ 10 ⁴⁾ - - 1) Thermoplastic polyurethane elastomer: Dong-A Chemical (Hardness 92A)
2) Modified masterbatch consisting of 100 parts by weight of TPU, 1 part by weight of silica and 10 parts by weight of EAA
3) Modified masterbatch consisting of 100 parts by weight of TPU, 2 parts by weight of silica and 20 parts by weight of EAA
4) Modified masterbatch consisting of 100 parts by weight of TPU, 3 parts by weight of silica and 30 parts by weight of EAA
* EAA: Dow, Japan
* Silica: Wet Silica (Rhodia), Korea

2. Preparation of Thermoplastic Polyurethane Film

Two large rollers were melted at 177 ± 2 ° C. using a twin screw extruder and extruded through a tee-die using the composition for thermoplastic polyurethane films prepared according to Examples 1 to 3 and Comparative Examples 1 and 2. Cooling was made to a constant thickness in between. At this time, a thickness of 145 ± 2 μm for a general keypad was prepared, and a film without eye-fish and pinhole phenomenon was produced.

3. Evaluation method of adhesive properties of the manufactured thermoplastic polyurethane film

In the case of the film prepared by the method of 2, the adhesive force was evaluated after the aging period of 3 days, and used to cut to a constant size without any washing process.

On the other hand, the primer (S-21) generally used for the film for the keypad is dried for 24 hours after the coating, the surface of the primer is completely dried and then pressed with a key made of polycarbonate using the instant adhesive. The adhesive strength is evaluated through the test, and the adhesive force is compared at one point instead of the unit area.

However, in the present invention, the films were prepared by the compositions prepared in Examples 1 to 3 and Comparative Examples 1 and 2, and the pretreatment bonding process and the pretreatment bonding as shown in the following [Table 2] for the clearer difference in adhesion. The adhesive properties were evaluated through the process.

NO fair Manufacturing process I process Pretreatment process
(Primer process) Primer ¹⁾ Application → Drying ²⁾ → Adhesive ³⁾ Application → Compression II process Pretreatment Process
Non-primer process Adhesive ³⁾ Application → Compression 1) S-21 (solvent type primer for thermoplastic polyurethane)
2) 24hr, RT
3) O-177, Alteco Korea
Adhesive is applied in small amount using syringe

4. Evaluation of adhesive properties of thermoplastic polyurethane film

The thermoplastic polyurethane films prepared by the methods of Examples 1 to 3 and Comparative Examples 1 and 2 were completely dried after applying a primer on the specimen, and then coated with a cyanoacrylate-based adhesive syringe before curing occurred. Covering and pressing the polycarbonate key (within about 3 seconds), and after about 24 hours to measure the adhesive force and the results are shown in Table 3 below.

(Unit: kg / cm) No Example Comparative example One 2 3 One 2 I process 1.5-1.78 2.0 ~ 2.25 2.25 or more 1.2 to 1.5 1.2 to 1.5 II process 0.9-1.0 1.0-1.3 1.25-1.5 0-0.25 0.5-0.75

As shown in Table 3, the composition for a thermoplastic polyurethane film for a film prepared according to the present invention has an excellent adhesive strength regardless of the use of a primer, compared to a general thermoplastic polyurethane elastomer, and its characteristic improvement is about 20%. It can be seen that the above is reached.

In addition, when comparing the difference in contact angle with the existing product as shown in Figures 1a to 1c, the thermoplastic polyurethane produced by the method of Examples 1 to 3 while showing a contact angle of 85 to 87 degrees for the existing product as a comparative example In the case of the elastic body, the contact angle of 68 to 69 is shown, and the surface tension tends to be remarkably slowed down, thereby improving the adhesive force.

As described above, the thermoplastic polyurethane composition excellent in the adhesive force of the present invention and a method for producing the same have been described with reference to the preferred embodiments, but those skilled in the art do not depart from the spirit and scope of the present invention as set forth in the claims below. It will be understood that various modifications and variations can be made within the scope of the invention.

Figure 1a is a photograph showing the results of evaluating the contact angle of the specimen using Example 1 according to the present invention,

Figure 1b is a photograph showing the results of evaluating the contact angle of the specimen using Example 2 according to the present invention,

Figure 1c is a photograph showing the results of evaluating the contact angle of the specimen using Example 3 according to the present invention,

Figure 2a is a photograph showing the result of evaluating the contact angle of the specimen using Comparative Example 1 according to the present invention,

Figure 2b is a photograph showing the results of evaluating the contact angle of the specimen using Comparative Example 2 according to the present invention.

Claims (8)

It is prepared by mixing 10 to 20 parts by weight of a modified masterbatch based on 90 parts by weight of a thermoplastic polyurethane substrate, The modified masterbatch is mixed with 100 parts by weight of the thermoplastic polyurethane substrate, 1 to 3 parts by weight of silica and 10 to 30 parts by weight of the polar polymer to maintain the die temperature of 130 ~ 180 ℃, screw speed of 45 ~ 60rpm It is melted in one twin screw extruder and made into pellets, The silica is dry silica using dry surface-treated silica having a BET specific surface area of 175 to 350 m 2 / g, an average particle diameter of 7 to 12 nm, and a pH of 3.7 to 4.7, or as a wet silica, a BET specific surface area of 240 to 340 Using wet surface-treated silica having a m 2 / g, CTAB specific surface area of 140 to 170 m 2 / g, specific gravity of 1.95 to 2.05, and a pH of 6.5 to 7.5, The polar polymer may be selected from one or more of ethylene vinyl acetate (EVA), ethylene butyl acrylate (EBA), ethylene methyl acrylate (EMA), and ethylene ethyl acrylate (EEA). The manufacturing method of this excellent composition for thermoplastic polyurethane films. delete delete delete delete delete delete delete

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