TWI660993B - Bidirectional tearable plastic thin film and the forming method thereof - Google Patents

Abstract

A two-way easily tearable plastic film composed of a continuous phase polymer, a dispersed phase polymer, and a co-solvent, wherein the continuous phase polymer accounts for 50% to 80% by weight and the dispersed phase polymer accounts for weight percentage It is 10% to 47%, and the weight percentage of the co-solvent is 3% to 20%. The plastic film of the present invention has a smooth surface and is easy to tear in all directions.

Description

Two-way easily tearable plastic film and manufacturing method thereof

The invention relates to a plastic film, in particular to a plastic film with two-way easy tearing property and a manufacturing method thereof.

Existing tapes are coated with adhesive material on the substrate (can be coated on one surface or two opposite surfaces of the substrate) to make a single-sided tape or a double-sided tape to achieve the adhesive effect. Among them, the existing tape uses cotton paper. As a substrate. However, tissue paper is a porous material. When the adhesive material is coated on the tissue paper, the adhesive material will penetrate into the interior of the tissue paper through the holes on the surface of the tissue paper, which will increase the cost. Therefore, there is a need to develop a new base material for adhesive tape. Reduce costs.

In addition, most of the existing medicinal or food packaging bags are mainly made of low-density polyethylene. The low-density polyethylene itself is soft and has excellent acid and alkali resistance. However, low-density polyethylene is a net-like structure, which has certain toughness and is difficult to tear directly. Therefore, when making low-density polyethylene into pharmaceutical packaging bags, it is still necessary to use a cutting tool to remove the internal medicinal materials, which is still inconvenient to use . Therefore, there is also a need to develop a new easy-to-tear pharmaceutical packaging material to improve user convenience.

The "prior art" paragraph is only used to help understand the content of the present invention, so the content disclosed in the "prior art" paragraph may include some conventional technologies that do not constitute the ordinary knowledge of those skilled in the art. The content disclosed in the "Prior Art" paragraph does not represent that content or The problem to be solved by one or more embodiments of the present invention has been known or recognized by those with ordinary knowledge in the technical field before the application of the present invention.

The main object of the present invention is to provide a plastic film with easy tearing property, and the plastic film has low tear strength and easy tearability in all directions, so that the user can arbitrarily tear the required length or width.

Yet another object of the present invention is to make a hermetically sealed packaging bag using a plastic film with easy tearing properties. The medicinal materials or food materials that need to be isolated from the air can be placed in the sealed packaging bag, and the user can easily tear it in any direction when taking it. The sealed packaging bag is cracked, and the medicinal materials or ingredients placed in the packaging bag are taken.

Another object of the present invention is to provide a plastic film with no pores on the surface and a smooth surface.

Another object of the present invention is to use a plastic film with no pores on the surface and a smooth surface as the base material of the adhesive tape to save the cost of the adhesive material.

A further object of the present invention is to use a plastic film with no pores on the surface and a smooth surface as a single-sided tape or a double-sided tape.

According to the above object, the present invention discloses a plastic film composed of a continuous phase polymer, a dispersed phase polymer, and a co-solvent, wherein the weight percentage of the continuous phase polymer is 50% to 80%, and the dispersed phase polymer accounts for The weight percentage is 10% ~ 47%, the weight percentage of the co-solvent is 3% ~ 20%, and the tear strength of the plastic film is low, the surface is smooth, and it is easy to tear in all directions.

According to the above, the present invention also discloses a method for manufacturing a plastic film, which includes: providing a continuous phase polymer, a dispersed phase polymer, and a co-solvent, wherein the weight of the continuous phase polymer is 100%. The proportion is 50% to 80%, the weight percentage of the dispersed phase polymer is 10% to 47%, and the weight percentage of the co-solvent is 3% to 20%. Next, the continuous phase polymer, the dispersed phase polymer, and the co-solvent are subjected to a pre-mixing process at room temperature to form a first mixture. Then, the first mixture is subjected to a kneading process so that the first mixture can be uniformly mixed to form a second mixture. A granulation process is performed on the second mixture to form a plurality of particles. Finally, these particles are subjected to a film blowing process or a casting process to form a plastic film with non-directionality and easy tearing.

10‧‧‧Provide continuous phase polymer, dispersed phase polymer and co-solvent

12‧‧‧ Perform a pre-mixing step to pre-mix the continuous phase polymer, dispersed phase polymer, and co-solvent to form a first mixture

14‧‧‧ performs a kneading step to knead a first plastic mixture to form a second plastic mixture

16‧‧‧ Perform a granulation step to granulate a second plastic mixture to form a plurality of plastic particles

18‧‧‧Performed a film blowing process to blow plastic particles to form a plastic film

20, 30‧‧‧ packing bags

22, 32‧‧‧ bag body

24, 38‧‧‧Sealing material

222, 340‧‧‧ Junction

224, 226, 342, 344‧‧‧ anywhere

322, 42‧‧‧plastic film

324, 326‧‧‧ polyethylene layer

40‧‧‧Tape

50‧‧‧ rubber coated

60‧‧‧ Double-sided tape

70‧‧‧ release paper

FIG. 1 is a flowchart showing the manufacturing process of a plastic film according to the technology disclosed in the present invention; FIG. 2A is a SEM diagram showing the surface porosity of a tissue paper according to the technology disclosed in the present invention; Technology, which shows the SEM image of the surface porosity of a plastic film; Figure 3A is a schematic diagram of an embodiment of using a plastic film to make a packaging bag according to the technology disclosed in the present invention; Figure 3B is a technology disclosed in the present invention, using A schematic diagram of another embodiment of a packaging bag made of a plastic film; FIG. 4 is a schematic diagram illustrating an embodiment of a roll-type single-sided tape according to the technology disclosed in the present invention; and FIG. 5 is a schematic view of the disclosed bag according to the present invention The technology is a schematic diagram showing an embodiment of a roll-type double-sided tape.

The foregoing and other technical contents, features, and effects of the present invention will be clearly presented in the following detailed description of a preferred embodiment with reference to the accompanying drawings. The following examples The terms of direction, such as: up, down, left, right, front or back, etc., are only directions referring to the attached drawings. Therefore, the directional terms used are used to illustrate and not to limit the present invention.

First, please refer to FIG. 1, which is a flowchart of manufacturing a plastic film according to the technology disclosed in the present invention. In FIG. 1, step 10 provides a continuous phase polymer, a dispersed phase polymer, and a co-solvent, wherein the continuous phase polymer and the dispersed phase polymer are incompatible with each other. The co-solvent is to increase the continuous phase polymer and the dispersed phase polymer. Miscible substances. In this step, the composition and proportion of the plastic film are 50% to 80% by weight of the continuous phase polymer, 10% to 47% by weight of the dispersed phase polymer, and 3% to 20% by weight of the co-solvent. %. Preferably, in another embodiment, the composition and proportion of the plastic film are: the weight percentage of the continuous phase polymer is 55% to 75%, the weight percentage of the dispersed phase polymer is 15% to 40%, and the cosolvent The weight percentage is 5% ~ 10%. In this embodiment, the continuous phase polymer is selected from the group consisting of polyolefin compounds and polyester compounds, and the dispersed phase polymer is selected from polystyrene, olefin copolymers, cyclic polyolefin compounds, and polyester compounds. A group of people. In addition, the polyolefin-based compound may be polyethylene, polypropylene, polyoxyethylene, polystyrene, or an ethylene-vinyl acetate copolymer, and the co-solvent is a styrene elastomer, such as a styrene-ethylene / diene block copolymer. (SEBS, styrene butadiene styrene block copolymer) or styrene-butadiene-styrene copolymer (SBS). In a preferred embodiment of the present invention, the purpose of the co-solvent is to quickly combine the continuous phase polymer with the dispersed phase polymer and increase the solubility. Among them, it is preferable to use a styrene-ethylene / diene block copolymer. Mixed with continuous phase polymer and dispersed phase polymer to form a plastic film with low tear strength.

Next, in step 12, a premixing step is performed, and a continuous phase polymer, a dispersed phase polymer, and a co-solvent are subjected to a premixing process to form a first mixture. In step 12, the continuous phase polymer, the dispersed phase polymer, and the co-solvent are respectively placed in a mixer, and a premixing step of 10 minutes to 15 minutes is performed at a speed of 100 rpm to 200 rpm at room temperature. First plastic However, the present invention is not limited thereto. The continuous phase polymer, the dispersed phase polymer, and the co-solvent can also be supplemented with other suitable operating conditions to obtain the first plastic mixture.

Next, in step 14, a kneading step is performed to knead the first plastic mixture to form a second plastic mixture. In this step, the first plastic mixture obtained in step 12 is placed in a screw kneader for re-mixing. The purpose is to thoroughly mix the polyolefin-based compound, polystyrene, and co-solvent in the first plastic mixture. Even. In addition, in this step, the screw mixer can be a single screw mixer or a twin screw mixer. In the preferred embodiment of the present invention, the twin screw mixer is used to complete the mixing process of step 14 . Next, in step 16, a granulation step is performed to granulate the second plastic mixture to form a plurality of plastic particles. In step 16, a common plastic granulation (also known as plastic pumping) method is used to first place the second plastic mixture in a bucket, and after heating, the second plastic mixture is extruded to form a bar. This step is the so-called spinning. Then, the strip-shaped plastic is subjected to a cooling step, and finally the strip-shaped plastic is cut into plastic particles one by one, thereby completing the granulation step.

Next, in step 18, a blown film process is performed to blown the plastic particles to form a plastic film. In this step, a plurality of plastic particles obtained in step 16 are placed in a blown film extrusion molding machine. After the plastic particles are melted, the molten plastic enters the die head of the mold, and passes through the die head first. After the spiral flow channel is guided into a circular film tube, the circular film tube is extruded through the die lip area, blown by the air in the film tube, taken up by the take-up roller and cooled by the peripheral cooling air to form a circular tube-shaped film. This film is the plastic film disclosed in the present invention.

It should be noted that the speed (v1) of the roller pulling the film tube upward is different from the speed (v2) of the sol emerging from the die exit. Generally, the stretching speed ratio (v1 / v2) is about 1 to 5 times. Produces strong stretching, making the thickness of the plastic film thinner. In addition, the thickness of the plastic film can be corrected by automatic film thickness monitoring, cooling air volume, and temperature. Therefore, the thickness of the plastic film can be adjusted with the stretching speed ratio (v1 / v2) and automatic monitoring of the film thickness, air volume and temperature of the wind ring The required thickness of the plastic film. In the embodiment of the present invention, the thickness of the plastic film is about 20 μm to 100 μm. In addition, in the aforementioned step 18, a plastic film disclosed in the present invention is formed by using a blown film process. In another preferred embodiment, a plastic film is formed by casting, wherein the casting method is also in the industry. The commonly used plastic film forming process will not be described here.

The plastic film formed according to the process steps of FIG. 1 is mixed with two mutually incompatible macromolecules, continuous phase polymer and dispersed phase polymer, and the co-solvent is added to adjust the physical properties. The tear strength is low, and the plastic film is non-directional, which means that the plastic film can easily tear in all directions. According to the above-mentioned material characteristics, the plastic film disclosed in the present invention can be applied to a disposable packaging material or as a base material of an adhesive tape, which is convenient for a user to tear the packaging material or to tear off the attached object.

Please refer to FIG. 2A and FIG. 2B at the same time. FIG. 2A is a SEM image showing the surface porosity of cotton paper in the prior art and FIG. 2B is a SEM image showing the surface porosity of the plastic film of the present invention according to the technology disclosed in the present invention . From FIG. 2A and FIG. 2B, at a resolution of 200 μm, the porosity distribution on the surface of the cotton paper can be clearly seen. Under the same resolution, the surface porosity of the plastic film of the present invention is lower than the surface porosity of the cotton paper, and can be regarded as a smooth surface.

Please refer to FIG. 3A. FIG. 3A is a schematic diagram illustrating an embodiment of using a plastic film to make a packaging bag according to the disclosed technology. In FIG. 3A, the packaging bag 20 includes a sealing material 24 and a bag body 22. The plastic film formed by the manufacturing process in FIG. 1 is used as the bag body 22 of the packaging bag 20. In this embodiment, since the packaging bag 20 has a smooth surface, which means that the surface of the bag body 22 has no pores, it has good air barrier properties. Therefore, by using the material characteristics of the bag body 22, the medicinal materials or food materials to be stored can be placed in the bag body 22, and then the thermoplastic plastic is used as the material of the sealing material 24 to seal the opening of the bag body 22. In order to achieve the purpose of preserving medicinal materials or ingredients. When the user wants to use the medicinal materials or ingredients in the packaging bag 20, The material of the body 22 is non-directional, has low tear strength, and is easy to tear. Therefore, it can be directly torn from the junction 222 of the sealing material 24 and the bag body 22 or any of the bags 224 and 226, and Without using a cutting tool such as a blade or scissors, the sealing material 24 can be separated from the bag body 22 and the medicinal materials or food materials placed in the bag body 22 can be taken out.

Please refer to FIG. 3B. 3B is a schematic cross-sectional view illustrating another embodiment of a packaging bag made of a plastic film according to the technology disclosed in the present invention. In the aforementioned packaging bag 20 in FIG. 3A, only a single layer of plastic film is used as the bag body 22 of the packaging bag 20. In FIG. 3B, the bag body 32 of the packaging bag 30 is composed of the plastic film 322 and the polyethylene (PE) layers 324 and 326 formed on the inner layer and the outer layer of the plastic film 322. In this embodiment, adding polyethylene layers 324 and 326 to the inner and outer layers of the bag body 32 can strengthen the overall rigidity of the packaging bag 30. In addition, similar to the bag body 22 described in FIG. 3A, the packaging bag 30 uses thermoplastic as the material of the sealing material 38 and is sealed at the opening of the bag body 32 to achieve the purpose of storing medicinal materials or food materials. When the user wants to use the medicinal materials or food ingredients in the packaging bag 30, since the material of the bag body 32 is non-directional, the tear strength is low, and the tearability is high, it can be directly from the junction of the sealing material 38 and the bag body 32. 340 or any place 342 and 344 of the bag body 32 can be torn directly, without the need of cutting tools such as a blade or scissors, the sealing material 38 can be separated from the bag body 32 and the medicinal materials placed in the bag body 32 can be taken out. Or ingredients.

It is to be noted here that whether the contents placed in the bag bodies 22 and 32 disclosed in FIG. 3A or FIG. 3B are not limited to the medicinal materials or food materials described in this embodiment, but also need to be isolated from the air. And saved objects. In this embodiment, the materials used as the sealing materials 24 and 38 of the packaging bags 20 and 30 may be thermoplastics. The thermoplastics are, for example, polyethylene (PE), polypropylene (PP), polystyrene (PS), and ABS resin. , Polyvinyl chloride (PVC), acrylic resin, nylon (PA), POM, polycarbonate (PC), fluorine resin, cellulose resin or polyethylene terephthalate (PET). The material of the sealing materials 24 and 38 can be selected according to the contents to be placed in the packaging bags 20 and 30. If the contents are edible medicinal materials or ingredients, you can choose polyethylene (PE) or polypropylene (PP), or the contents placed in the packaging bags 20, 30 are non-edible , You can choose polystyrene (PS), ABS resin, polyvinyl chloride (PVC), acrylic resin, nylon (PA), POM, polycarbonate (PC), fluorine resin, cellulose resin or Polyethylene terephthalate (PET), but the above selection is for illustration only and is not within the limits of the present invention. According to this, compared with the existing packaging bags made of polyethylene, the packaging bodies 22 and 32 of the packaging bags 20 and 30 made of plastic film can eliminate the need for users to use scissors or blades when unpacking. Such as cutting tools, the bag body 22, 32 can be easily torn along the junction 222 of the sealing material 24 and the bag body 22 or the junction 340 of the sealing material 38 and the bag body 32, improving the convenience of use.

Please refer to FIG. 4. FIG. 4 is a schematic diagram showing an adhesive tape according to the disclosed technology. In FIG. 4, the adhesive tape 40 includes a plastic film 42 as a base material and a glue 50. The glue 50 is coated on a surface of the plastic film 42, and can be made into a roll shape. In this embodiment, the glue 50 is, for example, glue or pressure-sensitive adhesive. It can be known from the SEM image of the plastic film of FIG. 2B that the surface of the plastic film 42 has no porosity (or small porosity) or can be regarded as a smooth surface. As in the prior art, cotton paper is used as the substrate of the tape to generate a large number (or large pores) of pores. Because the surface of the cotton paper has a large porosity, when the rubber is coated on the cotton paper, some of the rubber will penetrate into the pores of the cotton paper. Therefore, a thicker rubber needs to be applied to ensure the surface of the cotton paper. The thickness of the glue to ensure the adhesion of the tape, however, increasing the thickness of the glue also increases the cost of glue. Since the surface of the plastic film 42 of the present invention has no porosity, the glue 50 will not penetrate into the plastic film 42 after being coated on the surface of the plastic film 42, so that the thickness of the glue 50 coated on the plastic film 42 can be obtained from the existing In the technology, 25μm-30μm is reduced to 15μm-20μm, which saves the coating amount of the glue 50 by 20% -25%, which can greatly reduce the cost of the glue 50, so that the cost of making the tape is relatively reduced.

In addition, when the tape is in the shape of a roll, since the base material of the tape is a plastic film, its tear strength is low and it is easy to tear. When the user is using the tape, the tape 40 Tear off and attach to the object. For example, when moving companies move furniture, especially for cabinets or desks with doors or drawers, they use tape to fix those doors or drawers that are easy to move or turn during the moving process, but Generally, the adhesive tape is not easy to remove, and it is necessary to use a cutting tool such as scissors or a blade to remove the required size, so it is slightly inconvenient to use. The adhesive tape 40 made of the plastic film disclosed in the present invention has low tear strength and is easy to tear in all directions, that is, it can be arbitrarily removed from the position indicated by the dotted line in FIG. 4, which is convenient. A user tears a desired length from the roll tape 40 and attaches it to a door or drawer of these furnitures and fixes it. Because the adhesive tape 40 is easy to tear, when the adhesive tape 40 is to be removed from the door or drawer of these furnitures, it is easier to tear off the furniture than ordinary adhesive tapes, which is quite convenient for users. It should be noted that the dotted line in FIG. 4 is not limited to that, and can only be torn off at this position, but only a schematic diagram showing an arbitrary position.

Please refer to FIG. 5. FIG. 5 is a schematic diagram showing a roll-type double-sided tape according to the technology disclosed in the present invention. In FIG. 5, the double-sided adhesive tape 60 includes a plastic film 42 and a glue 50 as a base material, and the glue 50 is coated on the upper and lower surfaces of the plastic film 42. Similarly, the double-sided tape 60 may also be used. Made into a roll. In this embodiment, the adhesive 50 is the same as described above. The difference is that in order to achieve the double-sided adhesive tape 60 also being easy to tear, a layer of release paper 70 is applied on one of the adhesive 50 to make the entire double-sided adhesive tape 60. Can achieve the best tearability for user convenience. Similarly, the dashed line in FIG. 5 is not intended to limit the tear off only at this position, but only a schematic diagram showing an arbitrary position. In addition, the material and manufacturing method of the release paper 70 are not the main technical features of the present invention, and no further description is given here.

Therefore, according to the above embodiments, in order to further show that the single-sided adhesive tape and double-sided adhesive tape disclosed in the present invention have better tearability than the polyethylene film in the prior art, for each film in the machine direction , MD) and transverse direction (TD) to compare the breaking strength, tensile strength, elongation and tear strength, as shown in the table: It can be seen from the table that the break strength, tensile strength, elongation and tear strength of the single-sided tape or double-sided tape in the longitudinal or transverse direction are smaller than that of the prior art polyethylene film, which means that The film formed by using the continuous phase polymer, the dispersed phase polymer, and the co-solvent disclosed in the present invention has better tearability.

However, the above are only the preferred embodiments of the present invention. When the scope of implementation of the present invention cannot be limited by this, that is, the simple equivalent changes and modifications made according to the scope of the patent application and the description of the invention, All are still within the scope of the invention patent. In addition, any embodiment of the present invention or the scope of patent application does not need to achieve all the purposes or advantages or features disclosed by the invention. In addition, the abstract section and title are only used to assist the search of patent documents and are not intended to limit The scope of the right to make the invention. Moreover, the first, second, etc. mentioned in the description are only used to indicate the names of the components, and are not used to limit the upper or lower limit on the number of components.

Claims (10)

A plastic film includes: a continuous phase polymer; a dispersed phase polymer; and a co-solvent; wherein the continuous phase polymer accounts for 50% to 80% by weight, and the dispersed phase polymer accounts for the weight percentage 10% to 47%, the weight percentage of the co-solvent is 3% to 20%, the plastic film has a smooth surface, and the plastic film is non-directional; wherein an upper surface and a lower surface of the plastic film are respectively Has a polyethylene layer. According to the plastic film described in the first item of the patent application scope, it also includes an adhesive material on any surface of the plastic film or on the upper surface and the lower surface. The plastic film according to item 1 of the scope of patent application, wherein the weight percentage of the continuous phase polymer is 55% to 75%, and the weight percentage of the dispersed phase polymer is 15% to 40%, and The weight percentage of the co-solvent is 5% to 10%. The plastic film according to item 1 of the patent application scope, wherein the continuous phase polymer is selected from the group consisting of polyolefin compounds and polyester compounds, and the dispersed phase polymer is selected from polystyrene and olefins Copolymers, cyclic polyolefin compounds, and polyester compounds. The plastic film according to item 4 of the application, wherein the polyolefin-based compound is selected from the group consisting of polyethylene, polypropylene, polyoxyethylene, ethylene-vinyl acetate copolymer, and the like. The plastic film according to item 1 of the patent application scope, wherein the co-solvent is selected from the group consisting of a styrene-ethylene / diene block copolymer and a styrene-butadiene-styrene copolymer. A method for manufacturing a plastic film includes: providing a continuous phase polymer, a dispersed phase polymer, and a co-solvent, wherein the weight percentage of the continuous phase polymer is 50% to 80%, and the weight percentage of the dispersed phase polymer is 10% ~ 47%, and the weight percentage of the co-solvent is 3% -20%; performing a pre-mixing step on the continuous phase polymer, the dispersed phase polymer and the co-solvent to form a first plastic mixture; A mixing step is performed on the first plastic mixture to form a second plastic mixture; a granulation step is performed on the second plastic mixture to form a plurality of plastic particles; a film blowing step is performed on the plastic particles to Forming a non-directional and easily tearable plastic film; and adding a polyethylene layer to an upper surface and a lower surface of the plastic film, respectively. The manufacturing method according to item 7 of the scope of patent application, wherein the continuous phase polymer is selected from the group consisting of polyolefin compounds and polyester compounds, and the dispersed phase polymer is selected from polystyrene and olefins Copolymers, cyclic polyolefin compounds, and polyester compounds. The manufacturing method according to item 8 of the application, wherein the polyolefin-based compound is selected from the group consisting of polyethylene, polypropylene, polyoxyethylene, polystyrene, and an ethylene-vinyl acetate copolymer. The manufacturing method according to item 7 of the scope of the patent application, wherein the co-solvent is selected from the group consisting of a styrene-ethylene / diene block copolymer and a styrene-butadiene-styrene copolymer.