High-transparency low-haze degradable plastic film structure

Abstract

The utility model provides a degradable plastic film structure with high transparency and low haze, which comprises a core layer and a surface layer arranged on at least one side of the core layer, the core layer comprises at least one of polybutylene terephthalate-butylene adipate, poly (butylene succinate)-butylene adipate and poly (butylene succinate), the surface layer is polylactic acid; wherein the thickness ratio of the surface layer to the core layer is (5-20): (90-60). The high-transparency low-haze degradable plastic film structure provided by the utility model is simple in production process, and has good light transmittance and haze.

Description

Technical Field

[0001] The utility model relates to the technical field of degradable plastic films, and more specifically, to a high-transparency and low-haze degradable plastic film structure. Background Technique

[0002] Transparent packaging is pursued by many packaging manufacturers and consumers. At present, various soft packaging materials with different transparency levels of non-degradable plastic films have met the needs of the packaging market. However, since the production, manufacturing and packaging applications of degradable plastic films have just emerged not long ago, the application of degradable plastic films with good transparency in the soft packaging market is still blank.

[0003] The transparency of plastic films is mainly characterized by two optical performance indicators: light transmittance and haze. The light transmittance determines the visibility of the contents packaged in the film, and the haze determines the clarity of the contents visible through the packaging. The light transmittance index of plastic films reflects the loss of scattering and absorption of incident light by the film. The light transmittance is equal to the percentage of the light flux of the transmitted light to its incident light flux. The haze is the percentage of the transmitted light intensity deviated from the incident light by more than 2.5° to the total transmitted light intensity. According to the light transmittance and haze of plastic films, the materials can be divided into: 1. High-transparency and high-clarity materials: light transmittance above 90% and haze ≤ 1.5%; 2. Transparent and clear materials: light transmittance between 80% - 90% and haze between 1.5% - 3.0%; 3. Translucent materials: light transmittance between 50% - 80%. It has become a trend for degradable plastic films to replace non-degradable plastic films in the field of soft packaging applications. At present, the application of degradable plastic films in transparent packaging is still blank. The outer packaging film of cigarettes needs to clearly and without distortion display the patterns and texts inside the package. The transparent outer packaging of summer clothes and the outer packaging that needs to display the contents of the product all require high-transparency and low-haze degradable plastic films to replace the current packaging materials. When manufacturing transparent plastic films with non-degradable materials, the commonly used means are: ① reducing the dosage of anti-blocking agent; ② using anti-blocking agents with small particle sizes; ③ using inorganic anti-blocking agents with refractive indices similar to those of the film resin; ④ online chemical coating; ⑤ reducing the crystallinity of film forming, and so on.

[0004] However, the above conventional process means all have their usage defects. For example, using an opening agent masterbatch with a small particle size (1 - 2 μm) and reducing the addition amount of the opening agent brings problems such as scratches and protrusions easily occurring on the film during the production process; using the online coating method to coat a chemical coating of an opening agent with a nano - scale particle size on the film surface and adding a small amount or no small - particle - size opening agent masterbatch to the film resin brings the problem that the biaxially stretched film production line needs to be equipped with an online coating device and a coating liquid preparation system, which requires adding chemical coating materials and various auxiliary coating materials, increasing the production cost; adding opening agent particles with a refractive index similar to that of the film resin to the film has limited improvement in the transparency and clarity of the film; adopting the co - extrusion composite film production method with an ABA structure and only adding the opening agent masterbatch to the surface layer (A layer) of the film. Compared with the single - layer film structure, this method reduces the usage amount of the masterbatch, and the transparency and clarity of the film are improved to some extent, but it cannot achieve the effect of high transparency and high clarity; adding a small amount of chemical modifiers that hinder resin crystallization to the resin for producing the film, so as to reduce crystallization during the processes of sheet casting, stretching, and heat setting in the production of biaxially stretched films. This can improve the transparency and clarity of the film, but at the same time, it also deteriorates the properties such as heat resistance and mechanical strength of the film, restricting the application fields of the film.

[0005] In summary, there is currently a lack of a high - transparency, low - haze, degradable plastic film structure with simple production processes and low production costs in the existing technologies. Summary of the Invention

[0006] (1) Technical problems to be solved

[0007] The technical problem to be solved by the present invention is that the production processes of the existing high - transparency degradable plastic films are complex and the production costs are high.

[0008] (2) Technical solutions

[0009] To achieve the above object, the technical solution adopted by the present invention is:

[0010] The present invention provides a high - transparency, low - haze, degradable plastic film structure, including a core layer and surface layers provided on at least one side of the core layer. The core layer includes at least one of polybutylene terephthalate - butylene adipate, polybutylene succinate - butylene adipate, and polybutylene succinate. The surface layer is polylactic acid; wherein, the thickness ratio of the surface layer to the core layer is (5 - 20):(90 - 60).

[0011] Preferably, the surface layer includes a first surface layer and a second surface layer. The first surface layer is provided on one side of the core layer, and the second surface layer is provided on the other side of the core layer.

[0012] Preferably, the thickness ratio of the first surface layer: the core layer: the second surface layer = 5:90:5.

[0013] Preferably, the thickness ratio of the first surface layer: the core layer: the second surface layer = 20:60:20.

[0014] Preferably, the thickness ratio of the first surface layer: the core layer: the second surface layer = (5 - 20):(90 - 60):(5 - 20).

[0015] Preferably, the high - transparency and low - haze degradable plastic film structure is a film formed by biaxial stretching.

[0016] Preferably, the high - transparency and low - haze degradable plastic film structure is a uniaxially oriented stretched film with a stretching ratio of at least 1:(3 - 6) in the longitudinal direction.

[0017] Preferably, the high - transparency and low - haze degradable plastic film structure is a uniaxially oriented stretched film with a stretching ratio of at least 1:(3 - 6) in the transverse direction.

[0018] Preferably, the thickness of the surface layer is not less than 1 micron.

[0019] (III) Beneficial Effects

[0020] The above - mentioned technical solutions of the present utility model have at least the following advantages:

[0021] 1. Compared with the prior art, the high - transparency and low - haze degradable plastic film structure provided by the present utility model does not need to add any inorganic anti - blocking masterbatch, does not require on - line coating, and does not need to modify the ABA plastic film resin, simplifies the production process, and reduces the production cost.

[0022] 2. The present utility model forms a plastic film structure by compounding and stretching a core layer of a specific material and a surface layer of a specific material, and sets the thickness ratio between layers to ensure that the plastic film structure has good light transmittance and haze. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0024] Figure 1 It is a schematic structural diagram of the high - transparency and low - haze degradable plastic film structure provided by the embodiments of the present utility model.

[0025] Figure 2 This is the solution and test data of the specific embodiment provided by the embodiment of the present utility model.

[0026] The reference numerals in the figures are as follows:

[0027] 1, core layer; 2, first surface layer; 3, second surface layer. Specific embodiments

[0028] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present utility model clearer and more understandable, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0029] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly located on the other element or indirectly located on the other element. When an element is referred to as "connected to" another element, it can be directly connected or indirectly connected to the other element.

[0030] It should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present utility model, rather than indicating that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present utility model.

[0031] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating relative importance or indicating the quantity of technical features. In the description of the present utility model, "a plurality" means two or more unless otherwise specifically defined. The following describes the specific implementation of the present utility model in more detail with reference to specific embodiments:

[0032] As Figure 1 and Figure 2 shown, the embodiment of the present utility model provides a high-transparency and low-haze degradable plastic film structure, which includes a core layer 1 and a surface layer disposed on at least one side of the core layer 1. The core layer 1 includes at least one of polybutylene terephthalate-butylene adipate (PBAT), polybutylene succinate-butylene adipate (PBSA) and polybutylene succinate (PBS), and the surface layer is polylactic acid (PLA); wherein, the thickness ratio of the surface layer to the core layer is (5-20):(90-60).

[0033] As an alternative implementation of this embodiment, the surface layer includes a first surface layer 2 and a second surface layer 3. The first surface layer 2 is disposed on one side of the core layer 1, and the second surface layer 3 is disposed on the other side of the core layer 1.

[0034] As an alternative implementation of this embodiment, the thickness ratio of the first surface layer 2: the core layer 1: the second surface layer 3 = 5:90:5.

[0035] As an alternative implementation of this embodiment, the thickness ratio of the first surface layer 2: the core layer 1: the second surface layer 3 = 20:60:20.

[0036] As an alternative implementation of this embodiment, the thickness ratio of the first surface layer 2: the core layer 1: the second surface layer 3 = (5 - 20):(90 - 60):(5 - 20).

[0037] As an alternative implementation of this embodiment, the high - transparency and low - haze degradable plastic film structure is a film formed by biaxial stretching.

[0038] As an alternative implementation of this embodiment, the high - transparency and low - haze degradable plastic film structure is a uniaxially oriented stretched film in the longitudinal direction with a stretching ratio of at least 1:(3 - 6).

[0039] As an alternative implementation of this embodiment, the high - transparency and low - haze degradable plastic film structure is a uniaxially oriented stretched film in the transverse direction with a stretching ratio of at least 1:(3 - 6).

[0040] As an alternative implementation of this embodiment, the thickness of the surface layer is not less than 1 micron.

[0041] As Figure 2 shown in Table 1 below, the present utility model provides the following specific embodiments:

[0042] It should be noted that hereinafter, H - PLA represents the polylactic acid material produced by Hisun Biomaterials Co., Ltd.; D - PLA represents the polylactic acid material with the grade of 175 produced by Total Company of the United States; N - PLA represents the polylactic acid material produced by Nature Works Company of the United States.

[0043] Example 1

[0044] The core layer 1 is made of poly(butylene terephthalate-co-butylene adipate) (PBAT) resin material, and both the first surface layer 2 and the second surface layer 3 are made of H-PLA polylactic acid material. The thickness ratio of the first surface layer 2: the core layer 1: the second surface layer 3 is designed to be 10:80:10. A plastic film structure is prepared through the preparation process, and this plastic film structure is tested to obtain a light transmittance of 94.46% and a haze of 2.06% for this plastic film structure.

[0045] Example 2

[0046] The core layer 1 is made of poly(butylene terephthalate-co-butylene adipate) (PBAT) resin material, and both the first surface layer 2 and the second surface layer 3 are made of H-PLA polylactic acid material. The thickness ratio of the first surface layer 2: the core layer 1: the second surface layer 3 is designed to be 20:60:20. A plastic film structure is prepared through the same preparation process as in Example 1, and this plastic film structure is tested to obtain a light transmittance of 94.54% and a haze of 2.75% for this plastic film structure.

[0047] Example 3

[0048] The core layer 1 is made of poly(butylene terephthalate-co-butylene adipate) (PBAT) resin material, and both the first surface layer 2 and the second surface layer 3 are made of D-PLA polylactic acid material. The thickness ratio of the first surface layer 2: the core layer 1: the second surface layer 3 is designed to be 10:80:10. A plastic film structure is prepared through the same preparation process as in Example 1, and this plastic film structure is tested to obtain a light transmittance of 94.32% and a haze of 0.34% for this plastic film structure.

[0049] Example 4

[0050] The core layer 1 is made of poly(butylene terephthalate-co-butylene adipate) (PBAT) resin material, and both the first surface layer 2 and the second surface layer 3 are made of D-PLA polylactic acid material. The thickness ratio of the first surface layer 2: the core layer 1: the second surface layer 3 is designed to be 20:60:20. A plastic film structure is prepared through the same preparation process as in Example 1, and this plastic film structure is tested to obtain a light transmittance of 94.42% and a haze of 0.31% for this plastic film structure.

[0051] Example 5

[0052] The core layer 1 is made of polybutylene terephthalate-butylene adipate (PBAT) resin material, and both the first surface layer 2 and the second surface layer 3 are made of N-PLA polylactic acid material. The thickness ratio of the first surface layer 2: the core layer 1: the second surface layer 3 is designed to be 10:80:10, and a plastic film structure is prepared by the same preparation process as in Example 1. The plastic film structure is tested, and the light transmittance of the plastic film structure is obtained as 94.24% and the haze is 1.51%.

[0053] Example 6

[0054] The core layer 1 is made of polybutylene terephthalate-butylene adipate (PBAT) resin material, and both the first surface layer 2 and the second surface layer 3 are made of N-PLA polylactic acid material. The thickness ratio of the first surface layer 2: the core layer 1: the second surface layer 3 is designed to be 20:60:20, and a plastic film structure is prepared by the same preparation process as in Example 1. The plastic film structure is tested, and the light transmittance of the plastic film structure is obtained as 94.32% and the haze is 1.72%.

[0055] From the above Examples 1 to 6, it can be seen that the plastic film structure prepared by the present utility model has good light transmittance and haze.

[0056] The above are only the preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present utility model shall be included in the protection scope of the present utility model.

Claims

1. A highly transparent and low haze degradable plastic film structure, characterized in that: It comprises a core layer and a surface layer arranged on at least one side of the core layer, wherein the core layer comprises at least one of polybutylene terephthalate-butylene adipate, polybutylene succinate-butylene adipate and polybutylene succinate, and the surface layer is polylactic acid; wherein the thickness ratio of the surface layer to the core layer is (5-20):(90-60).

2. The highly transparent and low haze degradable plastic film structure according to claim 1, characterized in that: The surface layer includes a first surface layer and a second surface layer, wherein the first surface layer is arranged on one side of the core layer, and the second surface layer is arranged on the other side of the core layer.

3. The highly transparent and low haze degradable plastic film structure according to claim 2, characterized in that: The thickness of the first surface layer: the thickness of the core layer: the thickness of the second surface layer=5:90:

5.

4. The highly transparent and low haze degradable plastic film structure according to claim 2, characterized in that: The thickness of the first surface layer: the thickness of the core layer: the thickness of the second surface layer=20:60:

20.

5. The highly transparent and low haze degradable plastic film structure according to claim 2, characterized in that: The thickness of the first surface layer: the thickness of the core layer: the thickness of the second surface layer = (5-20): (90-60): (5-20).

6. The highly transparent and low haze degradable plastic film structure according to claim 1, characterized in that: The highly transparent and low-haze degradable plastic film structure is a film formed by biaxial stretching.

7. The highly transparent and low haze degradable plastic film structure according to claim 1, characterized in that: The high-transparency, low-haze, degradable plastic film structure is a stretched film that is uniaxially oriented in the longitudinal direction at a stretch ratio of at least 1:(3-6).

8. The highly transparent and low haze degradable plastic film structure according to claim 1, characterized in that: The high-transparency, low-haze, degradable plastic film structure is a stretched film that is uniaxially oriented in the transverse direction at a stretch ratio of at least 1:(3-6).

9. The highly transparent and low haze degradable plastic film structure according to claim 1, characterized in that: The thickness of the surface layer is not less than 1 micron.

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