Polymer stripping coating, membrane material containing polymer stripping coating and membrane material recovery method

Abstract

The invention provides a polymer stripping coating. The polymer stripping coating comprises sodium carboxymethyl cellulose, sodium polyacrylate, completely alcoholyzed polyvinyl alcohol, partially alcoholyzed polyvinyl alcohol, water, a reactant and a photoinitiator.

Description

Technical Field

[0001] The present invention relates to a polymer stripping coating, in particular to a water-swellable and water-insoluble polymer stripping coating, a film material containing the same, and a method for recycling the film material. Background Art

[0002] Most recyclers separate plastic films from bottle bodies, use the bottle bodies as the final recycling raw materials, and treat the plastic films as waste, for example, by burning. According to statistics, only 50% of the PET bottles produced on the market enter the recycling system, and about 7,000 tons of the labels on them are treated by burning.

[0003] In recent years, strippable coatings have been developed for use on plastic films and structural film materials. The recycling principle is to put the plastic films and structural film materials into a solution to remove the ink on their surfaces. At this time, the plastic films and structural film materials are recyclable. If the plastic films and structural film materials soaked in the solution are recycled, the emission of volatile organic compounds (VOC) and the waste treatment cost can be reduced.

[0004] Currently, the recycling method of plastic films and structural film materials with strippable coatings is to put the plastic films and structural film materials into an alkaline or acidic solution to remove the ink on the plastic films and structural film materials. However, the alkaline or acidic solution used in this deinking method will reduce its ink-removing efficiency as the number of uses increases. Therefore, as the number of uses of the alkaline or acidic solution increases, the alkaline or acidic waste liquid will also increase. Therefore, the problem of how to prepare a polymer stripping coating that reduces the use of alkaline or acidic solutions in the process of recycling plastic films and structural film materials has been widely studied. Summary of the Invention

[0005] The present invention is completed in view of the above problems. Its purpose is to provide a polymer stripping coating. And, the purpose of the present invention is also to provide a film material with an ink layer and a method for recycling the same.

[0006] The present invention provides a polymer stripping coating, comprising: sodium carboxymethylcellulose, sodium polyacrylate, fully alcoholized polyvinyl alcohol, partially alcoholized polyvinyl alcohol, water, a reaction agent, and a photoinitiator.

[0007] The present invention further provides a film material, comprising: a substrate, a polymer coating made of the above polymer stripping coating and disposed on the substrate, and an ink layer disposed on the polymer coating.

[0008] The present invention also provides a method for recovering a film material, comprising: a step of wetting and swelling the above-mentioned film material; and a step of applying stress to the above-mentioned film material to remove the above-mentioned film material so that the polymer coating together with the ink layer is separated from the substrate.

[0009] The polymer coating containing the polymer release coating of the present invention is disposed between the ink layer and the substrate. The polymer release coating has the characteristics of being water-absorbable and swellable and non-water-soluble, and it will present a swollen state after absorbing water. If the film material containing the polymer coating of the polymer release coating of the present invention after absorbing water is stirred, the polymer coating will be separated from the substrate together with the ink layer, so as to achieve the purpose of easy deinking and peeling. Therefore, when recovering a plastic film or a structural film having the polymer coating of the polymer release coating of the present invention on its surface, water (that is, without using an alkaline or acidic solution) and stirring can be used to separate the polymer coating together with the ink layer from the substrate. After filtering out the water used in the foregoing recovery process, it can be reused in the next recovery process, so that no waste liquid is generated, and the deinked plastic film and structural film can be recycled. Therefore, the present invention can reduce environmental pollution by improving the resource recovery efficiency of plastic films and structural films. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 Illustrating a film material having a polymer coating made of the polymer release coating of the present invention;

[0011] Figure 2 Illustrating a schematic diagram of the separation of the polymer coating together with the ink layer from the substrate;

[0012] Figure 3 Illustrating a method for recovering a film material according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] The detailed features and advantages of the present invention are described in detail in the following embodiments. The content is sufficient for those skilled in the art to understand the technical content of the present invention and implement it accordingly. According to the content disclosed in this specification, the claims and the drawings, those skilled in the art can easily understand the related purposes and advantages of the present invention. The following examples further illustrate the viewpoints of the present invention in detail, but do not limit the scope of the present invention in any way.

[0014] Hereinafter, the polymer release coating of the present invention, the film material containing the same, and the method for recovering the film material will be described in detail with reference to the drawings.

[0015] In this text, all features or conditions defined in the form of numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are only for the sake of brevity and convenience. Accordingly, the description of a numerical range or percentage range should be regarded as having covered and specifically disclosed all possible sub-ranges and individual numerical values (including integers and decimals) within the range, especially integer numerical values. For example, the range description of "1.0 to 8.0" should be regarded as having specifically disclosed all sub-ranges such as 1.0 to 8.0, 1.0 to 7.0, 2.0 to 8.0, 2.0 to 6.0, 3.0 to 6.0, 4.0 to 8.0, 3.0 to 8.0, etc., and covering the endpoint values, especially the sub-ranges defined by integer numerical values, and should be regarded as having specifically disclosed individual numerical values such as 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, etc. within the range.

[0016] In this text, on the premise that the object of the present invention can be achieved, a numerical value should be understood to have the precision of the significant digits of that numerical value. For example, the number 40.0 should be understood to cover the range from 39.50 to 40.49.

[0017] Unless restrictive terms such as "only" are used, one or more components or ingredients can also be added in the case of using "comprising" or "having" described in this specification.

[0018] When describing the positional relationship, for example, when describing the positional relationship between two components using "above", "on top of", "below", and "next to", unless terms such as "directly" or "exactly" are used, one or more other components can be arranged between these two components.

[0019] The sodium carboxymethyl cellulose used in the present invention can be any one or more commercially available products or self-made products. Herein, the sodium carboxymethyl cellulose used in the present invention is the sodium carboxymethyl cellulose produced by Di Yi Chemical Raw Materials Co., Ltd., but is not limited thereto.

[0020] The sodium polyacrylate used in the present invention can be any one or more commercially available products or self-made products. Herein, the sodium polyacrylate used in the present invention is the sodium polyacrylate produced by Nippon Shokubai Co., Ltd. or East Asia Synthetic Co., Ltd. in Taiwan, China, but is not limited thereto.

[0021] The fully alcoholized polyvinyl alcohol used in the present invention can be any one or more commercially available products or self-made products. Herein, the fully alcoholized polyvinyl alcohol used in the present invention is the fully alcoholized polyvinyl alcohol produced by Changchun Petrochemical Co., Ltd., but is not limited thereto.

[0022] The partially alcoholyzed polyvinyl alcohol used in the present invention can be any one or more commercially available products or homemade products. Here, the partially alcoholyzed polyvinyl alcohol used in the present invention is the partially alcoholyzed polyvinyl alcohol produced by Changchun Petrochemical Co., Ltd., but is not limited thereto.

[0023] In one embodiment of the present invention, the polymer release coating comprises: sodium carboxymethyl cellulose, sodium polyacrylate, completely alcoholysed polyvinyl alcohol, partially alcoholysed polyvinyl alcohol, water, a reactant, and a photoinitiator.

[0024] In another embodiment of the present invention, the weight percentage of sodium carboxymethyl cellulose can be 1.0% to 5.0%, the weight percentage of sodium polyacrylate can be 2.0% to 5.0%, the weight percentage of completely alcoholysed polyvinyl alcohol can be 2.0% to 5.0%, the weight percentage of partially alcoholysed polyvinyl alcohol can be 2.0% to 5.0%, the weight percentage of water can be 65.0% to 88.0%, the weight percentage of the reactant can be 3.0% to 10.0%, and the weight percentage of the photoinitiator can be 2.0% to 5.0%.

[0025] In another embodiment of the present invention, the reactants may include N-(2-hydroxyethyl)acrylamide (HEAA), acrylamide One or more of acryloyl morpholine (ACMO), dipropylene glycol diacrylate (DPGDA), 2-hydroxyethylmethacrylate (2-HEMA), and ethoxylated trimethylolpropane triacrylate (TMP(3EO)TA).

[0026] In another embodiment of the present invention, the photoinitiator may be 2-hydroxy-2-methylpropiophenone (photoinitiator-1173), 1-hydroxycyclohexylphenyl ketone (photoinitiator-184), or trimethylbenzoyldiphenylphosphine oxide (TPO).

[0027] In one embodiment of the present invention, the film material comprises: a substrate, a polymer coating made of the polymer release coating and disposed on the substrate, and an ink layer disposed on the polymer coating. In other embodiments of the present invention, the substrate may be a plastic film or a structural film. In other embodiments of the present invention, the film material may be a label or a packaging material. For details, please refer to Figure 1 .

[0028] Figure 1 A film material 1000 having a polymer coating made of the polymer release coating of the present invention is shown. The film material 1000 includes an ink layer 100, a polymer coating 200, and a substrate 300. The polymer coating 200 is located on the surface of the substrate 300, and the ink layer 100 is located on the surface of the polymer coating 200. That is, the polymer coating 200 is located between the ink layer 100 and the substrate 300. The ink layer 100 can be disposed on the surface of the polymer coating 200 by, for example, printing, spraying, etc. Here, the present invention uses a printing method, but is not limited thereto. The polymer coating 200 is made of the polymer release coating of the aforementioned embodiment. The polymer release coating can swell (show a swollen state) due to water absorption, and it is non-water-soluble.

[0029] Please refer to Figure 2 as well as Figure 3 . Figure 2 A schematic diagram showing the separation of the polymer coating layer together with the ink layer from the substrate; Figure 3 The method for recovering a film material according to an embodiment of the present invention is shown. The method for recovering a film material according to an embodiment of the present invention comprises: performing wet expansion on the film material 1000 S1, applying stress to the film material 1000 to remove the film material 1000 so that the polymer coating 200 together with the ink layer 100 and the substrate 300 are separated S2. The schematic diagram after separation is shown in Figure 2 .

[0030] In an embodiment of the present invention, the step of wet expanding the film material 1000 is to soak the film material 1000 in water, and the step of applying stress to the film material 1000 to remove the film material 1000 so that the polymer coating 200 together with the ink layer 100 is separated from the substrate 300 is to apply stress to the film material 1000 by means of stirring, but not limited thereto. More specifically, soaking the film material 1000 in water can cause the polymer coating 200 to absorb water and expand, thereby reducing the adhesion between the polymer coating 200 and the substrate 300. Then, by means of stirring, shear force is provided through the turbulence of water to separate the polymer coating 200 together with the ink layer 100 from the substrate 300. The stirring method described in the present invention can be carried out by means of a stirring device, manual stirring, etc. Herein, the embodiment of the present invention performs stirring by means of a stirring device, but not limited thereto. In another embodiment of the present invention, the step of wet expanding the film material 1000 is to place the film material 1000 in a steam chamber, and the step of applying stress to the film material 1000 to remove the film material 1000 so that the polymer coating 200 together with the ink layer 100 is separated from the substrate 300 is to apply stress to the film material 1000 by means of brushing. In another embodiment of the present invention, the step of wet expanding the film material 1000 is to soak the film material 1000 in water, and the step of applying stress to the film material 1000 to remove the film material 1000 so that the polymer coating 200 together with the ink layer 100 is separated from the substrate 300 is to apply stress to the film material 1000 by means of ultrasonic vibration, but not limited thereto.

[0031] In an embodiment of the present invention, the soaking time of the film material in water can be 25 minutes or more. In another embodiment of the present invention, the soaking time of the film material in water can be 25 minutes to 35 minutes. In another embodiment of the present invention, the soaking time of the film material in water can be 30 minutes.

[0032] In an embodiment of the present invention, the rotation speed of the stirring device can be 500 revolutions per minute (rpm) to 2000 revolutions per minute (rpm). In another embodiment of the present invention, the rotation speed of the stirring device can be 500 rpm to 1000 rpm. In another embodiment of the present invention, the rotation speed of the stirring device can be 1000 rpm.

[0033] In an embodiment of the present invention, the temperature of the film material soaked in water can be 50°C to 60°C. In another embodiment of the present invention, the temperature of the film material soaked in water can be 55°C to 60°C. In another embodiment of the present invention, the temperature of the film material soaked in water can be 60°C.

[0034] The following Tables 1 to 7 will illustrate the experimental results (i.e., the effect of separating the polymer coating together with the ink layer from the substrate) of the comparative examples and the examples.

[0035] The experimental methods for the comparative examples and the examples in Tables 1 to 7 below are as follows: the step of wet expanding the film material (containing the polymer release coating) is to soak the film material in water, and the step of applying stress to the film material to remove the film material so that the polymer coating together with the ink layer is separated from the substrate is to apply stress to the film material by means of stirring, and the film material is stirred at 60 °C for 30 minutes by a stirring device with a rotation speed of 1000 rpm.

[0036] Table 1

[0037]

[0038] Table 2

[0039]

[0040] Table 3

[0041]

[0042] Table 4

[0043]

[0044]

[0045] Table 5

[0046]

[0047] Table 6

[0048]

[0049] Table 7

[0050]

[0051] In Tables 1 to 7, the experimental results of the comparative examples and the examples are described as "poor", "good", and "excellent". Among them, the best experimental result is that of Example 3, followed by Example 1 and Example 2.

[0052] The substrates in the examples of the present invention are filtered out for subsequent recycling and reuse, and the filtered water can be reused in the next recycling process, so that no additional waste liquid is generated.

[0053] The advantages of the present invention are as follows: The filtered base material of the embodiments of the present invention is modified or designed for the green manufacturing end that can reduce process energy consumption and waste, enabling consumers to use new products containing the base material manufactured by the green manufacturing end. When consumers discard the products, the recycling plant can disassemble the products with the film material having the polymer coating containing the present invention on the surface, recycle the film material according to the method for recycling the film material of the present invention, and carry out the next recycling cycle. Applying the polymer stripping coating of the present invention can obtain at least the following advantages: reducing the discard of defective products in the process, reducing the label waste on recycled PET bottles, and reducing the carbon dioxide emissions generated by burning labels or packaging materials.

[0054] The polymer coating containing the polymer stripping coating of the present invention is disposed between the ink layer and the base material. The polymer stripping coating has the characteristics of being water-absorbable and swellable and non-water-soluble, and it will present a swollen state after absorbing water. If the film material containing the polymer coating containing the polymer stripping coating of the present invention after absorbing water is stirred, the polymer coating will be separated from the ink layer and the base material together, thus achieving the purpose of easy deinking and stripping. Therefore, when recycling a plastic film or a structural film having the polymer coating containing the polymer stripping coating of the present invention on the surface, water (i.e., without using an alkaline or acidic solution) and stirring can be used to separate the polymer coating from the ink layer and the base material together. After filtering out the water used in the foregoing recycling process, it can be reused in the next recycling process, so that no waste liquid is generated, and the deinked plastic film and the structural film can be recycled. Therefore, the present invention can reduce the environmental pollution by improving the resource recycling efficiency of plastic films and structural films.

[0055]

Symbol Explanation

[0056] 100: Ink layer

[0057] 1000: Film material

[0058] 200: Polymer coating

[0059] 300: Base material

[0060] S1, S2: Steps.

Claims

1. A polymer release coating, characterized in that, It includes: sodium carboxymethyl cellulose, sodium polyacrylate, fully alcoholized polyvinyl alcohol, partially alcoholized polyvinyl alcohol, water, a reactive agent, and a photoinitiator.

2. The polymer release coating according to claim 1, wherein, The weight percentage of the sodium carboxymethyl cellulose is 1.0% to 5.0%, the weight percentage of the sodium polyacrylate is 2.0% to 5.0%, the weight percentage of the fully alcoholized polyvinyl alcohol is 2.0% to 5.0%, the weight percentage of the partially alcoholized polyvinyl alcohol is 2.0% to 5.0%, the weight percentage of the water is 65.0% to 88.0%, the weight percentage of the reactive agent is 3.0% to 10.0%, and the weight percentage of the photoinitiator is 2.0% to 5.0%.

3. The polymer release coating according to claim 1, wherein, The reactant contains one or more of N-(2-hydroxyethyl)acrylamide (HEAA), acryloyl morpholine (ACMO), dipropylene glycol diacrylate (DPGDA), 2-hydroxyethyl methacrylate (2-HEMA), and ethoxylated trimethylolpropane triacrylate (TMP(3EO)TA). ​ 4. The polymer release coating according to claim 1, wherein, The photoinitiator is 2-hydroxy-2-methylpropiophenone (2-hydroxy-2-methylpropiophenone, photoinitiator-1173), 1-hydroxycyclohexyl phenyl ketone (1-hydroxycyclohexyl phenyl ketone, photoinitiator-184), or trimethylbenzoyl diphenylphosphine oxide (trimethylbenzoyl diphenylphosphine oxide, TPO).

5. A membrane material, characterized in that, It includes: a substrate; a polymer coating, made of the polymer release coating according to any one of claims 1 to 4 and disposed on the substrate; and an ink layer, disposed on the polymer coating.

6. The film material according to claim 5, wherein, The substrate is a plastic film or a structural film.

7. A method for recycling a membrane material, characterized in that, It includes: a step of wet expanding the film material according to claim 5; and a step of applying stress to the film material to remove the film material so that the polymer coating together with the ink layer is separated from the substrate.

8. The method for recycling film materials according to claim 7, wherein, The step of wet expanding the film material according to claim 5 is to put the film material into a steam chamber, and the step of applying stress to the film material to remove the film material so that the polymer coating together with the ink layer is separated from the substrate is to apply stress to the film material by means of brushing.

9. The method for recycling film materials according to claim 7, wherein, The step of wet expanding the film material according to claim 5 is to soak the film material in water, and the step of applying stress to the film material to remove the film material so that the polymer coating together with the ink layer is separated from the substrate is to apply stress to the film material by means of stirring.

10. The method for recycling film materials according to claim 7, wherein, The step of wet expanding the film material according to claim 5 is to soak the film material in water, and the step of applying stress to the film material to remove the film material so that the polymer coating together with the ink layer is separated from the substrate is to apply stress to the film material by means of ultrasonic vibration.

11. The method for recycling film materials according to claim 9, wherein, Soak the film material in water for 25 minutes to 35 minutes, and stir it with a stirring device, and the rotation speed of the stirring device is 500 revolutions per minute (rpm) to 2000 revolutions per minute (rpm).

12. The method for recycling film materials according to claim 11, wherein, Soak the film material in water at 50°C to 60°C.

13. The method for recycling the film material according to claim 12, wherein, Soak the film material in water at 50°C to 60°C for 30 minutes.

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