CN113460476B

CN113460476B - Large-capacity nozzle-added liquid self-standing bag and preparation method thereof

Info

Publication number: CN113460476B
Application number: CN202110743625.7A
Authority: CN
Inventors: 张羽; 高虎; 吴奇; 朱妙清; 冯润财
Original assignee: Amco Huizhou New Material Technology Co ltd
Current assignee: Amco Huizhou New Material Technology Co ltd
Priority date: 2021-06-30
Filing date: 2021-06-30
Publication date: 2023-03-21
Anticipated expiration: 2041-06-30
Also published as: CN113460476A

Abstract

The invention relates to a large-capacity spouted liquid self-standing bag which comprises a composite film, wherein the composite film comprises a connecting area and a non-connecting area, the connecting area is of a BOPP/BOPE// PE/PE multilayer composite structure, the non-connecting area is of a BOPP/INK/BOPE// PE/PE multilayer composite structure, the BOPP is the outermost layer of the spouted liquid self-standing bag, the innermost layer of the spouted liquid self-standing bag is of two-layer PE composite structure, the two-layer PE comprises extruded PE and inner PE, and the extruded PE is arranged between the BOPE and the inner PE. The present invention also relates to a method of making a large capacity self-supporting spout-liquid pouch as described above.

Description

Large-capacity nozzle-added liquid self-standing bag and preparation method thereof

Technical Field

The invention relates to the technical field of packaging, in particular to a large-capacity liquid self-standing bag with a mouth and a preparation method thereof.

Background

Spouted liquid stand-up pouches are widely used to package liquid, slurry, powder, and small granular products due to their excellent standing properties and stability. At present, most of the liquid self-supporting bags with mouths on the market, especially the liquid self-supporting bags with large capacity, generally adopt a multilayer composite structure of PET/NY/PE, and the multilayer composite structure has the advantages of high temperature resistance, high strength, strong production adaptability and the like, but the multilayer composite structure is not environment-friendly and can not be recycled. In order to meet the requirements of environmental protection and recycling, the prior art solution is to use polyolefin materials to replace the multilayer composite structure of PET/NY/PE.

Chinese patent CN 202110730608X describes a small-capacity spout-added liquid self-standing bag and a method for manufacturing the same, the small-capacity spout-added liquid self-standing bag is made of polyolefin material, and meets the requirements of environmental protection and recyclability, and the inner packaging capacity of the small-capacity spout-added liquid self-standing bag is 0.5-1.0L. However, the technical problems in the prior art are as follows: the self-supporting bag prepared from the polyethylene material in the prior art cannot realize high-capacity packaging.

In order to overcome the technical problem, the invention improves on the basis of the technical scheme of Chinese patent CN 202110730608X, thereby providing a large-capacity liquid self-supporting bag with a mouth added and a preparation method thereof. The method for producing BOPP described in the present invention is the same as the method for producing BOPP described in chinese patent CN 202110730608X.

Disclosure of Invention

In the present invention, a large capacity spouted liquid self-standing pouch is defined as a spouted liquid self-standing pouch having a liquid packaging capacity of 2.0 to 4.0L.

In order to achieve the purpose, the invention adopts the following technical scheme: a large capacity, spout, liquid stand-up pouch made from a composite film comprising an attachment area and a non-attachment area, the attachment area being a BOPP/BOPE// PE/PE multilayer composite structure and the non-attachment area being a BOPP/INK/BOPE// PE/PE multilayer composite structure. Forming accommodation space between the non-connection region behind the connection region sealing connection of a plurality of complex films, BOPP is the outmost of this large capacity's mouth that adds liquid self-reliance bag, and the inlayer of this large capacity's mouth that adds liquid self-reliance bag is two-layer PE compound, and two-layer PE is including crowded compound PE and inlayer PE, and crowded compound PE sets up between BOPE and inlayer PE.

Wherein, BOPP is a biaxial stretching polypropylene film, BOPE is a biaxial stretching polyethylene film, INK is a printing layer, and PE is a polyethylene film.

The large-capacity spout-equipped liquid self-standing bag provided by the invention has the advantages that the internal packaging capacity is improved, so that the connection strength of the connection area of the composite film after sealing connection is improved, and the liquid leakage caused by the breakage of the sealed connection part under the pressure when the large-capacity spout-equipped liquid self-standing bag is loaded with solution is prevented. Therefore, improvements in the structure of the joint region of the composite film and the manner of sealing the joint region are needed, specifically:

1. the connecting area of the composite membrane is a BOPP/BOPE// PE/PE multilayer composite structure, and the peel strength between the BOPP and the BOPE is not less than 1.5N/15mm;

3. the BOPE and the extrusion-coated PE of the connecting area are compounded, and the peel strength between the BOPE and the extrusion-coated PE is not less than 1.5N/15mm.

2. The sealing connection of the connection area is not connected by an adhesive.

Since the increase in the packaging capacity of the spouted liquid stand-up pouch increases the outer surface area, which negatively affects the mechanical properties (pressure resistance, drop resistance, impact resistance, etc.) of the spouted liquid stand-up pouch, in order to make the large-capacity spouted liquid stand-up pouch not inferior to the existing small-capacity spouted liquid stand-up pouch in terms of mechanical properties under the condition of packaging capacity increase, it is necessary to improve the structure of the composite film, specifically:

1. the thickness of BOPP of the composite film is 20-28 μm, the thickness of BOPE is 25-40 μm, the thickness of extrusion PE is 10-40 μm, and the thickness of inner PE is 120-200 μm;

the ratio of the thickness of the BOPP to the thickness of the BOPE is 1:1-2, the BOPE and the BOPP can play a synergistic effect to ensure that the spout-added liquid self-supporting bag still has better mechanical properties under the condition of increasing the external surface area

3. The ratio of the thickness of the extruded PE to the thickness of the inner PE is 1:5-15;

BOPE and crowded compound PE can play the synergism, BOPE and crowded compound PE can play the effect of tie coat and prevent that BOPP and inlayer PE from breaking away from the complex film, BOPE and crowded compound PE can play the effect of barrier layer and further promote the leakproofness of the mouth-added liquid self-reliance bag of large capacity simultaneously.

The invention also provides a method for preparing the large-capacity spout-added liquid self-standing bag, which specifically comprises the following steps:

firstly, printing on a corona surface of BOPP to prepare INK;

coating an adhesive on the printing surface of the INK, and compounding the corona surface of the BOPE to prepare a semi-finished composite film;

curing the semi-finished composite membrane for not less than 48 hours;

step four, preparing the cured semi-finished composite film, the extruded PE and the inner layer PE into a composite film by using a three-layer co-extrusion technology;

and step five, sequentially making bags and adding nozzles on the composite film.

The tensile strength MD/TD of the composite film prepared by the method is more than or equal to 50MPa, the breaking strength MD/TD is more than or equal to 45MPa, and the heat sealing strength is more than or equal to 50N/15mm. And the large capacity spouted liquid stand-up pouch prepared by the above method can pass drop test (height of 0.8m is dropped 3 times without breakage or cracking) and pressure test (60 s is maintained in a pressed state by a weight of 60kg without breakage or cracking), and is excellent in impact resistance thanks to the composite structure of the composite film.

Compared with the prior art, the technical scheme of the invention has at least the following beneficial effects:

1. the liquid self-standing bag with the mouth can realize large-capacity packaging, and the liquid self-standing bag with the mouth maintains excellent mechanical property under the condition of improving the packaging capacity;

2. the large-capacity spout-added liquid self-standing bag is prepared from polyolefin materials, and meets the requirements of environmental protection and recyclability;

3. the method for preparing the large-capacity liquid self-standing bag with the nozzle can be realized by the existing equipment for preparing the liquid self-standing bag with the nozzle, and the yield is not lower than 84%.

The following description will be given with reference to specific examples.

Detailed Description

It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

This embodiment provides a large capacity spouted liquid self-standing pouch having a liquid packaging capacity of 2.0-4.0L, preferably 2L, 3L or 4L.

The large capacity, spout, liquid stand-up pouch provided in this example was made using a composite film comprising an attachment zone and a non-attachment zone, the attachment zone being a BOPP/BOPE// PE multilayer composite structure and the non-attachment zone being a BOPP/INK/BOPE// PE multilayer composite structure.

This embodiment also provides a method for preparing the large capacity spouted liquid stand-up pouch described above, wherein the method is implemented by existing equipment for preparing a spouted liquid stand-up pouch, and the method specifically comprises the following steps:

the method comprises the steps of firstly, carrying out corona treatment on the surface layer of BOPP to obtain a corona surface, and printing the corona surface of the BOPP by using printing ink, wherein the corona surface of the BOPP is easy to combine with the printing ink, and higher adhesive force and ink adhesive force are expressed. After printing is completed on the corona surface of the BOPP, high-temperature treatment is required to be performed, so that INK for printing is cured to obtain INK, in this embodiment, a drying oven is used for high-temperature treatment, and the temperature of the drying oven is controlled to be 40-70 ℃. In the embodiment, the unreeling machine and the reeling machine cooperatively provide the moving driving force of the BOPP, and the BOPP is sequentially printed and processed at high temperature on a moving path, wherein the unreeling tension of the unreeling machine is 30-50N, the reeling tension of the reeling machine is 50-70N, and the printing speed is 100-200m/min.

And secondly, carrying out corona treatment on the surface layer of the BOPE to obtain a corona surface, wherein the stripping strength of the BOPP and the BOPE can be improved when the corona surface of the BOPP and the corona surface of the BOPE are compounded. Coating an adhesive on the printing surface of the INK and then compounding the corona surface of the BOPE to prepare a semi-finished composite film, wherein the adhesive used in the embodiment is selected from one or more of polyvinyl alcohol compound glue, polyurethane two-component glue and modified polyolefin adhesive, and is preferably polyvinyl alcohol compound glue. The gluing amount is 3.0-3.5gsm when the printing surface of the INK is coated with the adhesive, the unreeling tension of the BOPP is 60-100N, the unreeling tension of the BOPE is 40-100N and the reeling tension of the reeling machine is 100-200N in the compounding process of the INK and the BOPE. The semi-finished composite film needs to be subjected to high-temperature treatment to enable the adhesive to be cured, so that an oven is arranged on a path where the semi-finished composite film moves to a winding machine, the temperature of the oven is controlled to be 55-85 ℃, and the tension of the oven is 18-30N.

Step three, placing the semi-finished composite film which is wound by the winding machine into a curing chamber and curing at room temperature for not less than 48 hours;

and step four, preparing the cured semi-finished composite film, the extruded PE and the inner layer PE into a composite film through a three-layer co-extrusion die head, wherein the temperature of the die head is 320-330 ℃, the gap of the die head is 120-150mm, then cooling the composite film through a cooling roller, the temperature of the cooling roller is 18-25 ℃, and after cooling the composite film, finishing winding through a winding machine. In the process, the unreeling tension of the semi-finished composite film is 80-150N, the unreeling tension of the extruded PE and the unreeling tension of the inner layer PE are both 70-150N, and the reeling tension of the reeling machine is 130-250N.

And step five, cutting the rolled composite film on a splitting machine after aging treatment, and sequentially making a bag and adding a nozzle to the cut composite film to finish the preparation of the large-capacity nozzle-added liquid self-standing bag. In this embodiment, when the slit composite film is used for making a bag, the connection region of the composite film needs to be sealed and connected to form a self-standing bag, the inner side of the self-standing bag is the inner layer PE, and the sealing connection is performed by using a heat sealing cutter, specifically, the bottom knife temperature of the heat sealing cutter is controlled to be 200-235 ℃, the transverse knife temperature is controlled to be 160-210 ℃, and the bag making speed is 50-70 PCs/min. In this embodiment, the nozzle is implemented by using the prior art scheme, and therefore, the details are not repeated herein.

The mechanical properties such as pressure resistance and drop resistance of the large-capacity nozzle-added liquid self-standing bag prepared by the method provided by the embodiment are equivalent to those of the large-capacity nozzle-added liquid self-standing bag with the existing PET/NY/PE multilayer composite structure.

The self-standing spout liquid pouch provided by this embodiment can achieve a large packaging capacity at the same time. The reasons for excellent mechanical properties and high yield are:

1. the connecting area of the composite film is of a BOPP/BOPE// PE/PE multilayer composite structure, a heat sealing cutter is adopted for heat sealing when the connecting areas of the composite films are in sealing connection, inner-layer PEs of the composite films are heated and melted into a whole by the heat sealing cutter after being in close contact, and heat sealing is completed.

2. The inventor finds through multiple tests that the connection strength of the connection region after heat sealing is positively correlated with the thickness of the inner layer PE, and the connection strength of the connection region after heat sealing can meet the sealing requirement of the large-capacity spouted liquid self-standing bag when the thickness of the inner layer PE is not less than 120 μm, but when the thickness of the inner layer PE is more than 200 μm, the heat conduction of the heat sealing cutter to the inner layer PE when the connection region is subjected to heat sealing is influenced due to the excessively thick thickness of the inner layer PE, so that the sealing performance is influenced, and the thickness of the inner layer PE is limited to be 120-200 μm.

3. The surface area of the spouted liquid self-supporting bag is increased along with the increase of the packaging capacity, and in order to not reduce the mechanical property of the spouted liquid self-supporting bag, the BOPE is arranged to play a role in synergistic reinforcement with the BOPP, the inventor finds through multiple tests that the thickness of the BOPP is positively correlated with the tensile strength and the breaking strength of the composite film, the thickness of the BOPP is negatively correlated with the heat-sealing strength, the thickness of the BOPE is negatively correlated with the heat-sealing strength, the peeling strength between the BOPP and the BOPE is influenced by the ratio of the thickness of the BOPP to the thickness of the BOPE (gradually changed from positive correlation to negative correlation as the ratio is increased), therefore, when the thickness of the BOPP is 20-28 mu m, the thickness of the BOPE is 25-40 mu m, and the ratio of the thickness of the BOPP to the thickness of the BOPE is 1:1-2, the BOPP and the BOPE can achieve the optimal synergistic effect, namely, the peeling strength between the BOPP and the BOPE is not less than 1.5N/15mm, the tensile strength (TD) of the composite film, the breaking strength is not less than 50 Md, and the four-15 Md strength (TD) are not less than 50/15 mm in balance.

4. Because the BOPE is arranged, the extrusion-coated PE is required to be arranged to be used as a transition layer, the thickness of the extrusion-coated PE cannot be too thick, the ratio of the thickness of the extrusion-coated PE to the thickness of the inner layer PE is 1:5-15, and if the extrusion-coated PE is not arranged, the inventor finds that the inner layer PE is easy to separate from the BOPE in the process of preparing the composite film by using the co-extrusion die head.

5. When the thickness of the extruded PE is 10-40 μm, the peeling strength of the extruded PE and the BOPE is optimal (not less than 1.5N/15 mm), and when the thickness of the extruded PE is too low or too high, the peeling strength of the extruded PE and the BOPE is reduced.

6. According to the method for preparing the liquid self-standing bag with the mouth, the process setting, the parameter setting of each process section and the multilayer composite structure of the liquid self-standing bag with the mouth are matched, so that the large-capacity liquid self-standing bag with the mouth is prepared by using the conventional equipment for preparing the liquid self-standing bag with the mouth in the pressure-resistant range and the high-temperature-resistant range of BOPP, BOPE and PE.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is specific and detailed, but not to be understood as limiting the scope of the invention. It should be noted that various changes and modifications can be made by those skilled in the art without departing from the spirit of the invention, and these changes and modifications are all within the scope of the invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A large capacity spouted liquid stand-up pouch comprising a composite film characterized by: the composite film comprises a connecting area and a non-connecting area, wherein the connecting area is of a BOPP/BOPE// PE/PE multilayer composite structure, the non-connecting area is of a BOPP/INK/BOPE// PE/PE multilayer composite structure, the BOPP is the outermost layer of the spout-adding liquid self-standing bag, the innermost layer of the spout-adding liquid self-standing bag is of a two-layer PE composite structure, the two-layer PE comprises extruded PE and an inner layer PE, and the extruded PE is arranged between the BOPE and the inner layer PE.

2. A self-supporting, spouted liquid pouch according to claim 1, wherein: the thickness of the BOPP is 20-28 μm, the thickness of the BOPE is 25-40 μm, the ratio of the thickness of the BOPP to the thickness of the BOPE is 1:1-2, and the peel strength between the BOPP and the BOPE is not less than 1.5N/15mm.

3. The spouted liquid stand-up pouch of claim 2, wherein: the thickness of the extruded PE is 10-40 μm, the thickness of the inner layer PE is 120-200 μm, the ratio of the thickness of the extruded PE to the thickness of the inner layer PE is 1:5-15, and the peel strength between the BOPE and the extruded PE is not less than 1.5N/15mm.

4. A method of making a self-supporting spouted liquid pouch according to any one of claims 1 to 3, comprising the steps of: step one, printing on a corona surface of the BOPP to prepare the INK; coating an adhesive on the printing surface of the INK, and compounding the corona surface of the BOPE to prepare a semi-finished composite film; curing the semi-finished composite film; fourthly, preparing the cured semi-finished composite film, the extruded PE and the inner layer PE into a composite film by a three-layer co-extrusion technology; and step five, sequentially carrying out bag making and mouth adding on the composite film.

5. The method of claim 4, wherein: in the first step, the printing speed of the corona surface printing of the BOPP is 100-200m/min, and high-temperature treatment is carried out after printing to enable printing liquid to be cured at high temperature to form the INK.

6. The method of claim 4, wherein: in the second step, the adhesive is selected from one or more of polyvinyl alcohol compound glue, polyurethane two-component glue and modified polyolefin adhesive.

7. The method of claim 6, wherein: the adhesive is polyvinyl alcohol compound glue.

8. The method of claim 4, wherein: in the third step, the curing time of the semi-finished composite membrane is not less than 48 hours.