A ffs packaging film and a method for manufacturing the same

Abstract

The application discloses a kind of FFS packaging film and its preparation method, using LLDPE and low entanglement UHMWPE in-situ polymerization resin micro powder, nanometer montmorillonite and low melting point activated dispersion component to prepare pre-dispersion master batch;Low melting point activated component is using any one of erucic acid amide, oleic acid amide, stearic acid amide, ethylene stearic acid amide and aluminate coupling agent compound, and the compound ratio is 2 / 1, and after compounding, the use amount is 15-50wt% of the weight of montmorillonite;Pre-dispersion master batch is added in middle layer and outer layer resin in film production to blow FFS packaging film, and FFS packaging film is three-layer co-extruded film, and the basic formula is inner layer LDPE / mLLDPE 70 / 30, middle layer is HDPE / mLLDPE / LLDPE 60 / 20 / 20, and outer layer mLLDPE / LLDPE 40 / 60, and the application has the technical features of being capable of improving the comprehensive mechanical properties of film.

Description

Technical Field

[0001] This invention relates to a packaging film and its preparation method, and more specifically, to an FFS packaging film and its preparation method, belonging to the field of polyethylene modified materials. Background Technology

[0002] FFS bags are an integrated heavy-duty packaging film technology that combines bag making (Film), filling (Fill), and sealing (Sealing). They are primarily used in automated packaging lines for large-scale chemical synthetic resin granules and have experienced rapid development in China in recent years. To save costs, the industry is constantly pursuing thinner FFS films while ensuring their strength, stiffness, puncture resistance, and impact resistance meet industry standards and the requirements of automated packaging lines. Currently, the market demand for FFS packaging films is increasing. With the pursuit of lower film costs, and to meet the increasingly demanding requirements of thinner and faster automated packaging, as well as preventing damage during storage and transportation, traditional resin substrates can no longer achieve the performance goals of FFS films: "thin yet stiff, thin yet strong." Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides an FFS packaging film and its preparation method, which possess technical characteristics such as improved overall mechanical properties of the film.

[0004] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0005] This invention discloses a method for preparing an FFS packaging film, the method comprising the following steps:

[0006] Step 1) Pre-dispersed masterbatch is prepared by in-situ polymerization of LLDPE and low-entanglement UHMWPE resin micro powder, nano-montmorillonite, and low-melting-point activated dispersion component; the low-melting-point activated component is composed of any one of erucamide, oleamide, stearamide, and ethylene stearamide with an aluminate coupling agent, the compounding ratio is 2 / 1, and the amount used after compounding accounts for 15 to 50 wt% of the weight of montmorillonite;

[0007] Step 2) In film production, pre-dispersed masterbatch is added to the middle and outer layer resins to blow FFS packaging film.

[0008] Preferably, step 1) specifically includes: first, placing nano-montmorillonite and low-melting-point activating components in cyclohexane solvent and stirring at high speed for 30 minutes at 50±5℃, then stopping heating and drying the solvent while stirring; adding in-situ polymerized resin micro powder and mixing at high speed, then using a honey-refining extrusion machine to refining and granulating at below 130℃ to obtain pre-dispersed masterbatch.

[0009] Preferably, the parameters of LLDPE are: MFR value 2.0~4.0 g / 10min, density 0.918~0.920 g / cm³. 3 Linear low-density polyethylene copolymerized with 1-hexene; parameters of low-entanglement UHMWPE in-situ polymerized resin micro powder: Mw 100-300 million, micro powder particle size 10-120μm; parameters of nano-montmorillonite: fineness 600-2000 mesh, preferably 800-1200 mesh.

[0010] Preferred parameters for low-entanglement UHMWPE in-situ polymerized resin micro powder: Mw 1.2 million to 2 million, micro powder particle size 30 to 70 μm.

[0011] Preferably, the amount used after compounding accounts for 25-35 wt% of the weight of montmorillonite.

[0012] Preferably, the proportions of each component in the pre-dispersed masterbatch are 15 wt% LLDPE in-situ polymerized resin micro powder, 35 wt% UHMWPE in-situ polymerized resin micro powder, and 40 wt% nano-montmorillonite.

[0013] The present invention discloses an FFS packaging film, wherein the FFS packaging film is a three-layer co-extruded film with a basic formulation of inner layer LDPE / mLLDPE 70 / 30, middle layer HDPE / mLLDPE / LLDPE 60 / 20 / 20, and outer layer mLLDPE / LLDPE 40 / 60.

[0014] Preferably, 5-7 wt% of predispersed masterbatch is added to the middle layer of the basic formulation, and 3-5 wt% of predispersed masterbatch is added to the outer layer of the basic formulation.

[0015] Beneficial effects:

[0016] 1. The FFS packaging film of the present invention increases the comprehensive mechanical properties of the film by introducing a low-entanglement UHMWPE component; the layered structure of nano-montmorillonite limits the entanglement tendency of UHMWPE molecular chains during processing and avoids the generation of film crystal points.

[0017] 2. The activated and dispersed components, through high-speed mechanical interaction with nano-montmorillonite in cyclohexane solvent, fully wet the nanosheets, thereby playing a role in peeling off the sheets and organicating the surface of inorganic powders, promoting the dispersion of inorganic powders and obtaining better interfacial effects.

[0018] 3. Even with a 10% reduction in the thickness of the FFS film, its comprehensive mechanical properties still meet the requirements of the BB / T0058-2011 industry standard. Detailed Implementation

[0019] The present invention will be further described below with reference to the embodiments in the specification, but the present invention is not limited to the following embodiments.

[0020] The industry's continuous pursuit of thinner FFS films has led to a decrease in film stiffness and strength, affecting the automatic packaging and pickup efficiency, and resulting in frequent breakage during storage and transportation. This invention primarily provides a low-entanglement ultra-high molecular weight polyethylene (UHMWPE) modified FFS packaging film and its preparation method, achieving the comprehensive mechanical performance requirements of the film under thinning conditions. The FFS film of this invention is modified and reinforced by introducing low-entanglement UHMWPE resin into the middle and outer layers. Literature and patent search results show that FFS film-specific resins mainly focus on the selection of polyethylene raw materials such as LDPE, HDPE, LLDPE, and mLLDPE, and the formulation ratios of each layer. This patent provides a special material for the middle and outer layers. By introducing low-entanglement UHMWPE, this special material fundamentally improves the puncture resistance, impact resistance, and tensile strength of the middle and outer layers of the FFS film, thereby obtaining a relatively thin FFS heavy-duty packaging film with excellent comprehensive performance. This invention features improved comprehensive mechanical properties of the film and can achieve both reinforcement and thinning of the FFS film.

[0021] The product of this invention is tested according to national standards. The specific test methods are as follows:

[0022] The film thickness shall conform to GB / T 6672-2001.

[0023] Tensile strength testing shall be conducted in accordance with the provisions of GB / T 1040.1-2018 standard.

[0024] Impact failure quality shall be assessed in accordance with the provisions of GB / T 9639.1-2008.

[0025] The tear strength of the trousers shall be tested in accordance with the provisions of GB / T 16578.1 standard.

[0026] Reference example:

[0027] The FFS film has a thickness of 144 μm, tensile strength (longitudinal / transverse) of 25 MPa / 24 MPa, impact breaking mass (surface / folded edge) of 620 g / 306 g, and trouser tear strength (longitudinal / transverse) of 105 kN·m. -1 / 122kN·m -1 .

[0028] The embodiments of the present invention are not limited to embodiments formed by taking the left endpoint value, the right endpoint value, or the middle value of each range value, but also include specific embodiments formed by taking any value from each range value. The following are five specific embodiments.

[0029] Example 1:

[0030] A pre-dispersed masterbatch was added, wherein the UHMWPE resin micropowder in the pre-dispersed masterbatch had a Mw of 1 million and a particle size of 10 μm, the nano-montmorillonite had a fineness of 600 mesh, and the activating component accounted for 15 wt% of the montmorillonite. The resulting FFS film had a thickness of 131 μm, a tensile strength (longitudinal / transverse) of 27 MPa / 25 MPa, an impact breaking mass (surface / folded edge) of 615 g / 303 g, and a trouser tear strength (longitudinal / transverse) of 106 kN·m. -1 / 120kN·m -1 .

[0031] Example 2:

[0032] A pre-dispersed masterbatch was added, wherein the UHMWPE resin micropowder in the pre-dispersed masterbatch had a Mw of 1.2 million and a particle size of 30 μm, the nano-montmorillonite had a fineness of 800 mesh, and the activating component accounted for 25 wt% of the montmorillonite. The resulting FFS film had a thickness of 129 μm, a tensile strength (longitudinal / transverse) of 28 MPa / 26.5 MPa, an impact breaking mass (surface / folded edge) of 646 g / 313 g, and a trouser tear strength (longitudinal / transverse) of 112 kN·m. -1 / 131kN·m -1 .

[0033] Example 3:

[0034] A pre-dispersed masterbatch was added, wherein the UHMWPE resin micropowder in the pre-dispersed masterbatch had a Mw of 2 million and a particle size of 70 μm, the nano-montmorillonite had a fineness of 1200 mesh, and the activating component accounted for 35 wt% of the montmorillonite. The obtained FFS film had a thickness of 132 μm, a tensile strength (longitudinal / transverse) of 28.8 MPa / 27.1 MPa, an impact breaking mass (surface / folded edge) of 651 g / 317 g, and a trouser tear strength (longitudinal / transverse) of 113 kN·m. -1 / 129kN·m -1 .

[0035] Example 4:

[0036] A pre-dispersed masterbatch was added, wherein the UHMWPE resin micropowder in the pre-dispersed masterbatch had a Mw of 3 million and a particle size of 120 μm, the nano-montmorillonite had a fineness of 2000 mesh, and the activating component accounted for 50 wt% of the montmorillonite. The obtained FFS film had a thickness of 133 μm, a tensile strength (longitudinal / transverse) of 25.1 MPa / 24.6 MPa, an impact breaking mass (surface / folded edge) of 614 g / 311 g, and a trouser tear strength (longitudinal / transverse) of 108 kN·m. -1 / 123kN·m -1 .

[0037] Example 5:

[0038] A pre-dispersed masterbatch was added, wherein the UHMWPE resin micropowder in the pre-dispersed masterbatch had a Mw of 1.7 million and a particle size of 50 μm, the nano-montmorillonite had a fineness of 1000 mesh, and the activating component accounted for 30 wt% of the montmorillonite. The obtained FFS film had a thickness of 128 μm, a tensile strength (longitudinal / transverse) of 28.9 MPa / 27.6 MPa, an impact breaking mass (surface / folded edge) of 660 g / 318 g, and a trouser tear strength (longitudinal / transverse) of 112 kN·m. -1 / 131kN·m -1 .

[0039] Based on a comprehensive parameter comparison, this invention discloses an FFS packaging film and its preparation method, which has the characteristics of improving the overall mechanical properties of the film. It can meet the performance requirements of heavy-duty packaging bags even when the film is thinned, and provides a green and environmentally friendly production solution for FFS film manufacturers.

[0040] Finally, it should be noted that the present invention is not limited to the above embodiments, and many variations are possible. All variations that can be directly derived or conceived by those skilled in the art from the disclosure of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A method for preparing an FFS packaging film, characterized in that... The preparation method includes the following steps: Step 1): Pre-dispersed masterbatch is prepared using LLDPE in-situ polymerized resin micro powder, low-entanglement UHMWPE in-situ polymerized resin micro powder, nano-montmorillonite, and a low-melting-point activating component. The low-melting-point activating component is composed of any one of erucamide, oleamide, stearamide, or ethylene stearamide combined with an aluminate coupling agent at a ratio of 2 / 1, and the amount used after combination accounts for 15-50 wt% of the weight of montmorillonite. Step 2): In film production, pre-dispersed masterbatch is added to the middle and outer layer resins to blow FFS packaging film; Step 1) specifically includes: First, nano-montmorillonite and the low-melting-point activating component are placed in cyclohexane solvent and stirred at high speed for 30 min at 50±5℃. Then, heating is stopped and the solvent is dried while stirring. In-situ polymerized resin micro powder is added and mixed at high speed. Then, the mixture is compounded and granulated at below 130℃ using an integrated internal mixing and extrusion machine to obtain pre-dispersed masterbatch. LLDPE is a linear low-density polyethylene copolymerized with 1-hexene, with the following parameters: MFR value 2.0~4.0 g / 10 min, density 0.918~0.920 g / cm³. 3 Linear low-density polyethylene copolymerized with 1-hexene; parameters of low-entanglement UHMWPE in-situ polymerized resin micro powder: Mw 100~300 million, micro powder particle size 10~120μm; parameters of nano-montmorillonite: fineness 600~2000 mesh.

2. The method for preparing an FFS packaging film according to claim 1, characterized in that: Parameters of low entanglement UHMWPE in-situ polymerized resin micro powder: Mw 1.2 million to 2 million, micro powder particle size 30 to 70 μm.

3. The method for preparing an FFS packaging film according to claim 1, characterized in that: The amount used after compounding accounts for 25-35 wt% of the weight of montmorillonite.

4. The method for preparing an FFS packaging film according to claim 1, characterized in that: The proportions of each component in the pre-dispersed masterbatch are as follows: 15wt% LLDPE in-situ polymerized resin micro powder, 35wt% UHMWPE in-situ polymerized resin micro powder, and 40wt% nano-montmorillonite.