Stretching and wrapping film for transport packaging and preparation method of stretching and wrapping film

Abstract

The invention relates to the technical field of wrapping films, and particularly discloses a stretching wrapping film for transport packaging and a preparation method of the stretching wrapping film. The stretching and wrapping film for transport packaging comprises 100 parts of a mixture; 40 to 50 parts of a tackifier; the mixture comprises 160 to 240 parts of metallocene polyethylene, 4 to 7 parts of polyolefin elastomer and 230 to 270 parts of linear low density polyethylene; the preparation method comprises the following steps: mixing the metallocene polyethylene, the polyolefin elastomer and the linear low-density polyethylene to obtain a mixture; and plasticizing and mixing the mixture and the tackifier, and carrying out tape casting, cooling and rolling to obtain the stretching and wrapping film for transportation and packaging. According to the tensile wrapping film for transport packaging, by adding the metallocene polyethylene and the polyolefin elastomer, the mechanical strength and extensibility of the wrapping film are improved, stress relaxation or breakage is not prone to occurring under the high stretch rate of an automatic wrapping machine, and the tensile wrapping film still has good binding force on heavy goods.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wrapping film, more particularly, it relates to a stretch wrapping film for transportation packaging and a preparation method thereof. BACKGROUND

[0002] With the rapid development of modern logistics and warehousing industry, the stretch wrapping film for transportation packaging has become a key material for fixing, protecting and unitizing goods due to its excellent stretch performance, self-adhesion and cost-effectiveness.

[0003] Traditional stretch wrapping films are usually made of linear low-density polyethylene as the main raw material through blow molding or casting process, which have high elongation and puncture resistance, and can effectively prevent damage of goods caused by vibration, friction or moisture during transportation.

[0004] During the packaging process, the stretch wrapping film is pre-stretched to a certain ratio by an automatic wrapping machine to reduce the packaging time and the use amount of the stretch wrapping film. However, the traditional stretch wrapping film is prone to stress relaxation or rupture under high stretch rate of the automatic wrapping machine, resulting in a decrease in the binding force of the stretch wrapping film on heavy goods. SUMMARY

[0005] In order to improve the mechanical properties of the stretch wrapping film, the present application provides a stretch wrapping film for transportation packaging and a preparation method thereof.

[0006] In the first aspect, the present application provides a stretch wrapping film for transportation packaging, which adopts the following technical scheme: A stretch wrapping film for transportation packaging comprises the following components in parts by weight: 100 parts of a mixture; 40-50 parts of an adhesion enhancer; The mixture comprises the following components in parts by weight: 160-240 parts of a metallocene polyethylene; 4-7 parts of a polyolefin elastomer; 230-270 parts of a linear low-density polyethylene; The metallocene polyethylene has a melt flow rate of 1.0-3.5 g / 10 min at 190℃ / 2.16 kg.

[0007] By adopting the technical scheme, the metallocene polyethylene with high mechanical properties and processing stability is used, and in the processing of the polyolefin elastomer, the linear low density polyethylene and the tackifier, the raw materials are fully melted to form a melt with more uniform fluidity, the surface of the wrapping film is smooth, the wrapping film has excellent mechanical properties and elongation properties, and the wrapping film is not prone to stress relaxation or rupture under high elongation of the automatic wrapping machine, and has good binding force for heavy goods.

[0008] Preferably, the metallocene polyethylene is composed of metallocene polyethylene A, metallocene polyethylene B, metallocene polyethylene C and metallocene polyethylene D. The metallocene polyethylene A has a density of 913 kg / m 3 , a test method of ISO 1183, a melt flow rate of 1.0-2.0 g / 10 min at 190℃ / 2.16 kg, and a test method of ISO 1133. The metallocene polyethylene B has a density of 0.918 g / cm 3 , a test method of ASTM D1505, a melt flow rate of 1.8-3.5 g / 10 min at 190℃ / 2.16 kg, and a test method of ASTM D1238. The metallocene polyethylene C has a density of 0.912 g / cm 3 , a test method of ASTM D1505, a melt flow rate of 1.0-2.0 g / 10 min at 190℃ / 2.16 kg, and a test method of ASTM D1238. The metallocene polyethylene D has a density of 0.920 g / cm 3 , a melt flow rate of 1.0-1.4 g / 10 min at 190℃ / 2.16 kg, and a test method of ASTM D1238.

[0009] By adopting the technical scheme, the metallocene polyethylene A, the metallocene polyethylene B, the metallocene polyethylene C and the metallocene polyethylene D of the specific types are mixed and compounded and then added into the mixture, the wrapping film has excellent processing stability, high tensile strength and excellent elongation properties, and is suitable for packaging of heavy goods.

[0010] Preferably, the mixture includes the following components in the following weight fractions: The metallocene polyethylene A is 40-60 parts. The metallocene polyethylene B is 50-70 parts. The metallocene polyethylene C is 40-60 parts. The metallocene polyethylene D is 30-50 parts. The polyolefin elastomer is 4-7 parts. Linear low density polyethylene 230-270 parts.

[0011] By adopting the technical scheme, the components are added according to the weight parts, the weight proportion of the metallocene polyethylene in the obtained mixture is in the range of 40-47%, the prepared wrapping film has high tensile strength and elongation at break, especially when the weight proportion of the metallocene polyethylene is 44.6%, the tensile strength and elongation at break of the wrapping film are the highest, and the wrapping film is suitable for being stretched by an automatic wrapping machine and is suitable for packaging heavy goods.

[0012] Preferably, the weight ratio of the metallocene polyethylene A, the metallocene polyethylene B, the metallocene polyethylene C and the metallocene polyethylene D is 1:(1.2-1.4):(0.8-1.2):(0.6-1.0).

[0013] By adopting the technical scheme, the metallocene polyethylene A has both flexibility and tear resistance, the metallocene polyethylene B has good puncture resistance, the metallocene polyethylene C has good processing performance, and the metallocene polyethylene D has high elongation. Therefore, various kinds of metallocene polyethylenes are added according to the weight parts to prepare a wrapping film, and the wrapping film has high tensile strength and elongation at break and has excellent mechanical properties and elongation.

[0014] Preferably, the polyolefin elastomer has an elastic density of 0.862 g / cm 3 The melt flow rate at 190℃ / 2.16kg is 1.0-2.0 g / 10min.

[0015] By adopting the technical scheme, the polyolefin elastomer has good melt strength and elasticity, and has excellent adhesion with the metallocene polyethylene. Therefore, the wrapping film prepared by using the polyolefin elastomer and the metallocene polyethylene as a mixture has high tensile strength and elongation at break and has excellent mechanical properties and elongation.

[0016] Preferably, the linear low density polyethylene has a melt flow rate at 190℃ / 2.16kg of 0.5-2.0 g / 10min.

[0017] By adopting the technical scheme, the linear low density polyethylene has good tensile properties and processing stability, and is used as a main material to be plasticized and extruded with the metallocene polyethylene to prepare a wrapping film by casting film forming, and the wrapping film has excellent mechanical properties and elongation.

[0018] Preferably, the tackifier has a melt viscosity of 500-300 mPa·s at 160℃ and a softening point of 85-105℃.

[0019] In a second aspect, the application provides a method for preparing a stretch wrapping film for transportation packaging, which adopts the following technical scheme: A method for preparing a stretch wrapping film for transportation packaging, comprising the following steps: S1: mixing metallocene polyethylene, polyolefin elastomer and linear low density polyethylene to obtain a mixture; S2: plasticizing and mixing the mixture and tackifier, then casting, cooling and winding to obtain a stretch wrapping film for transportation packaging; The temperature for plasticizing is 190-260℃.

[0020] By adopting the above technical scheme, the metallocene polyethylene, polyolefin elastomer and linear low density polyethylene are first mixed into a mixture, and then the mixture is plasticized and mixed, which is conducive to the plasticization of each raw material to form a uniform melt, improves the mechanical properties and extensibility of the wrapping film after casting film, and enables the wrapping film to still have good binding force on heavy goods after high stretching.

[0021] In summary, the application has the following beneficial effects: 1. In the application, the metallocene polyethylene with a specific melt flow rate is used together with the polyolefin elastomer, linear low density polyethylene and tackifier in the plasticizing extrusion and casting film process, and the melt flow is more uniform, the surface of the wrapping film is smooth, and the wrapping film still has high mechanical properties and resilience and good binding force on heavy goods after high stretching; 2. In the application, a plurality of specific types of metallocene polyethylene are preferably mixed into the mixture, which not only has excellent processing stability, but also can endow the wrapping film with higher tensile strength and extensibility, and is more suitable for high heavy goods packaging; 3. The method of the application has simple preparation method, and the mixture and tackifier are plasticized and mixed before casting, which is conducive to the migration of the tackifier to the surface of the wrapping film, improves the self-adhesion of the wrapping film, and makes it not easy to fall off when packaging goods. DETAILED DESCRIPTION

[0022] The application will be further described in detail below in combination with examples.

[0023] Performance detection The stretch wrapping film for transportation packaging prepared in the examples of the application and the wrapping film prepared in the comparative examples were detected for tensile strength and elongation at break, and the detection method was as follows: Tensile strength: detected according to GB / T1040.3; Elongation at break: detected according to BB / T0024-2004. Examples

[0024] Example 1 A stretch wrapping film for transportation packaging, the components and their corresponding weights (kg) are shown in the following table.

[0025] The method for preparing the stretch wrapping film for transportation packaging comprises the following steps: S1: half weight of the metallocene polyethylene A, metallocene polyethylene B, metallocene polyethylene C and metallocene polyethylene D, polyolefin elastomer and linear low density polyethylene are added into the screw extruder B, and stirring and mixing are carried out under the condition of 56.3 r / min, to obtain the mixed material in the screw extruder B; The remaining metallocene polyethylene A, metallocene polyethylene B, metallocene polyethylene C and metallocene polyethylene D, polyolefin elastomer and linear low density polyethylene are added into the screw extruder C, and stirring and mixing are carried out under the condition of 58 r / min, to obtain the mixed material in the screw extruder C; S2: S21: first, half weight of the tackifier is added into the screw extruder A for plastic melting, then extruded into the distributor, and finally extruded into the left die, to obtain the left tackifier melt; First, the remaining tackifier is added into the screw extruder D for plastic melting, then extruded into the distributor, and finally extruded into the right die, to obtain the right tackifier melt; After the mixed material in the screw extruder B and the mixed material in the screw extruder C are plastic melted, they are first extruded into the distributor together, and then extruded into the middle die, to obtain the mixed material melt; S22: the left tackifier, the left tackifier and the right tackifier melt pass through the corresponding die and enter the casting machine at the same time, and then the film is casted, cooled and shaped, and wound, to obtain the stretch wrapping film for transportation packaging.

[0026] In the embodiment of the application, the extrusion speed of the screw extruder A for plastic melting is 67 r / min, and the extrusion temperature is divided into five zones, the first zone is 190℃, the second zone is 200℃, the third zone is 235℃, the fourth zone is 245℃, and the fifth zone is 260℃; The extrusion speed of the screw extruder B for plastic melting is 56.3 r / min, and the extrusion temperature is divided into five zones, the first zone is 190℃, the second zone is 200℃, the third zone is 235℃, the fourth zone is 245℃, and the fifth zone is 260℃; The extrusion speed of the screw extruder C for plastic melting is 65 r / min, and the extrusion temperature is divided into five zones, the first zone is 190℃, the second zone is 200℃, the third zone is 235℃, the fourth zone is 245℃, and the fifth zone is 260℃; The extrusion speed of the screw extruder D for plastic melting is 67 r / min, and the extrusion temperature is divided into five zones, the first zone is 190℃, the second zone is 200℃, the third zone is 235℃, the fourth zone is 245℃, and the fifth zone is 260℃.

[0027] The temperature of the distributor was 260°C.

[0028] The temperature of the middle die was 250°C; the temperature of the left and right dies was 270°C.

[0029] Examples 2-3 A stretch wrapping film for transportation packaging, which is different from Example 1 in that the components and their corresponding weights (kg) are shown in the following table.

[0030] The stretch wrapping films for transportation packaging prepared in Examples 1-3 of the present application were subjected to tensile strength and elongation at break detection, and the detection results are shown in the following table.

[0031] Through data analysis of the above table, it can be seen that the stretch wrapping films for transportation packaging prepared in Examples 1-3 have a transverse tensile strength of up to 25.80-30.40 MPa, a longitudinal tensile strength of up to 25.90-30.40 MPa, a transverse elongation at break of up to 1000.20-1165.36 MPa, and a longitudinal elongation at break of up to 690.50-783.36 MPa. This shows that the stretch wrapping films for transportation packaging prepared in Examples 1-3 of the present application have excellent tensile strength and elongation at break, good elongation performance, and high mechanical properties, and are not prone to stress relaxation or breakage during stretching, and still have high binding force on heavy goods after stretching.

[0032] At the same time, compared with Examples 2 and 3, Example 1 has higher tensile strength and elongation at break. This shows that the mixed material contains 44.6% of metallocene polyethylene in the total raw material for preparing the stretch wrapping film for transportation packaging, which can improve the mechanical properties of the stretch wrapping film for transportation packaging.

[0033] Examples 4-6 A stretch wrapping film for transportation packaging, which is different from Example 1 in that the components and their corresponding weights (kg) are shown in the following table.

[0034] The stretch wrapping films for transportation packaging prepared in Examples 1, 4, 5, and 6 of the present application were subjected to tensile strength and elongation at break detection, and the detection results are shown in the following table.

[0035] Through data analysis of the above table, it can be seen that the stretch wrapping film for transportation packaging prepared in Examples 1, 4 and 5 has a transverse tensile strength of 25.60-30.40 MPa, a longitudinal tensile strength of 23.00-30.40 MPa, a transverse elongation at break of 1102.61-1165.36 MPa, and a longitudinal elongation at break of 752.00-783.36 MPa.

[0036] Compared with Example 6, Examples 1, 4 and 5 have higher tensile strength and elongation at break. Thus, it is shown that, in the total raw materials for preparing the stretch wrapping film for transportation packaging, the weight ratio of Mitsui Chemical 1520SP, ExxonMobil 3518CB, ExxonMobil 2012MA and ExxonMobil 2010MA is 1:(1.2-1.4):(0.8-1.2):(0.6-1.0), which can improve the mechanical properties of the stretch wrapping film for transportation packaging and still have good elongation after stretching.

[0037] Example 7 A stretch wrapping film for transportation packaging, which is different from Example 1 in that the metallocene polyethylene has the following grades shown in the table Example 8 A stretch wrapping film for transportation packaging, which is different from Example 1 in that the linear low density polyethylene has the grade of Qilu Petrochemical DFDA-7042.

[0038] The stretch wrapping film for transportation packaging prepared in Examples 1, 7 and 8 is subjected to tensile strength and elongation at break detection, and the detection results are shown in the following table.

[0039] Through data analysis of the above table, it can be seen that, compared with Example 1, the tensile strength and elongation at break of Examples 1, 7 and 8 are reduced. Thus, it is shown that, in the total raw materials for preparing the stretch wrapping film for transportation packaging, the metallocene polyethylene is composed of Mitsui Chemical 1520SP, ExxonMobil 3518CB, ExxonMobil 2012MA and ExxonMobil 2010MA, and the linear low density polyethylene adopts Zhenhai Refining and Chemical DFDA-7042, and the stretch wrapping film for transportation packaging prepared thereby has better mechanical properties.

[0040] Comparative Example Comparative Example 1 A stretch wrapping film, which is different from Example 1 in that the metallocene polyethylene has the grade of Enable TM 2005PA, and has a melt flow rate of 0.5 g / 10 min at 190℃ / 2.16 kg.

[0041] Comparative Example 2 A stretch wrapping film, different from Example 1 in that the metallocene polyethylene is Exceed TM m4518.PA Cast, the melt flow rate at 190℃ / 2.16kg is 4.5g / 10min.

[0042] Comparative Examples 3-4 A stretch wrapping film, different from Example 1 in that the components and their corresponding weights (kg) are shown in the following table.

[0043] Comparative Example 5 A stretch wrapping film, different from Example 1 in that the amount of metallocene polyethylene added is 0.

[0044] The stretch wrapping films prepared in Comparative Examples 1-5 of the present application were tested for tensile strength and elongation at break, and the test results are shown in the following table.

[0045] Through data analysis of the above table, compared with the stretch wrapping films prepared in Comparative Examples 1-2, the transverse tensile strength of Example 1 was relatively increased by 52-54.47%, the longitudinal tensile strength was relatively increased by 37.53-40.15%, the transverse elongation at break was relatively increased by 18.67-19.93%, and the longitudinal elongation at break was relatively increased by 52-54.47%. This indicates that when the melt flow rate of the metallocene polyethylene at 190℃ / 2.16kg is 1.0-3.5g / 10min in the preparation of the stretch wrapping film for transportation packaging of the present application, the tensile strength and elongation at break of the stretch wrapping film for transportation packaging can be improved, so that after stretching at a high stretching rate on an automatic wrapping machine, stress relaxation or breakage is less likely to occur, and the stretch wrapping film still has good binding force for heavy goods.

[0046] Compared with the stretch wrapping films prepared in Comparative Examples 3-4, the transverse tensile strength of Example 1 was relatively increased by 39.19-48.95%, the longitudinal tensile strength was relatively increased by 25.94-32.77%, the transverse elongation at break was relatively increased by 20.08-21.36%, and the longitudinal elongation at break was relatively increased by 16.78-17.65%. This indicates that by controlling the amount of metallocene polyethylene added in the preparation of the stretch wrapping film for transportation packaging of the present application, the tensile strength and elongation at break of the stretch wrapping film for transportation packaging can be improved.

[0047] Compared with the stretch wrapping film prepared in Comparative Example 5, the transverse tensile strength of the stretch wrapping film of Example 1 is relatively increased by 118.23%, the longitudinal tensile strength is relatively increased by 83.13%, the transverse elongation at break is relatively increased by 27.96%, and the longitudinal elongation at break is relatively increased by 25.83%. Thus, it is shown that, by adding the metallocene polyethylene in the total raw materials for preparing the stretch wrapping film for transportation packaging, the tensile strength and the elongation at break of the stretch wrapping film for transportation packaging can be improved.

[0048] The specific embodiments are only an explanation of the present application, which is not a limitation to the present application, and the person skilled in the art can make modifications to the embodiments without creative contribution according to the needs after reading the specification, but as long as the modifications are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A stretch wrap film for transport packaging, characterized in that: The composition comprises the following components in parts by weight: 100 parts of mixed material; 40-50 parts of tackifier; The mixture comprises the following components in parts by weight: 160-240 parts of metallocene polyethylene; 4-7 parts of polyolefin elastomer; 230-270 parts of linear low-density polyethylene; The metallocene polyethylene has a melt flow rate of 1.0 to 3.5 g / 10 min at 190° C. / 2.16 kg.

2. The stretch wrap film for transport packaging according to claim 1, characterized in that: The metallocene polyethylene is composed of a mixture of metallocene polyethylene A, metallocene polyethylene B, metallocene polyethylene C and metallocene polyethylene D; The density of the metallocene polyethylene A is 913 kg / m 3 , the melt flow rate at 190℃ / 2.16 kg is 1.0~2.0g / 10min; The density of metallocene polyethylene B is 0.918 g / cm 3 , the melt flow rate at 190℃ / 2.16 kg is 1.8~3.5 g / 10min; The density of metallocene polyethylene C is 0.912g / cm 3 , the melt flow rate at 190℃ / 2.16 kg is 1.0~2.0 g / 10min; The density of metallocene polyethylene D is 0.920 g / cm 3 , the melt flow rate at 190℃ / 2.16 kg is 1.0~1.4 g / 10min.

3. The stretch wrap film for transport packaging according to claim 2, characterized in that: The mixture comprises the following components in parts by weight: 40-60 parts of metallocene polyethylene A; 50-70 parts of metallocene polyethylene B; 40-60 parts of metallocene polyethylene C; 30-50 parts of metallocene polyethylene D; 4-7 parts of polyolefin elastomer; 230-270 parts of linear low-density polyethylene.

4. The stretch wrap film for transport packaging according to claim 3, characterized in that: The weight ratio of the metallocene polyethylene A, metallocene polyethylene B, metallocene polyethylene C and metallocene polyethylene D is 1:(1.2-1.4):(0.8-1.2):(0.6-1.0).

5. The stretch wrap film for transport packaging according to claim 1, characterized in that: The elastic density of the polyolefin is 0.862 g / cm 3 , the melt flow rate at 190℃ / 2.16 kg is 1.0~2.0g / 10min.

6. The stretch wrap film for transport packaging according to claim 1, characterized in that: The linear low-density polyethylene has a melt flow rate of 0.5 to 2.0 g / 10 min at 190° C. / 2.16 kg.

7. The stretch wrap film for transport packaging according to claim 1, characterized in that: The tackifier has a melt viscosity of 500-300 mPa·s at 160°C and a softening point of 85-105°C.

8. The method for preparing the stretch wrap film for transport packaging according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1: mixing metallocene polyethylene, polyolefin elastomer and linear low-density polyethylene to obtain a mixture; S2: plasticizing and mixing the mixture and the tackifier, casting, cooling, and winding to obtain a stretch film for transportation packaging; The plasticizing temperature is 190-260°C.

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