Paper-plastic sealing film suitable for cold drink blister cup and application thereof

Abstract

The application provides a paper-plastic sealing film suitable for cold drink blister cups and application thereof, and relates to the technical field of sealing films.The paper-plastic sealing film comprises a first polyester film layer, a paper base layer, a second polyester film layer and a polyolefin heat-seal layer arranged in sequence.The paper-plastic sealing film has good flatness, can realize the same automatic film suction and film falling process as the aluminum-plastic sealing film, and after passing through a low-temperature tunnel at-35 DEG C to-45 DEG C, the paper-plastic sealing film and the blister cup still have good sealing strength, meet the sealing requirement of products, and the paper-plastic sealing film has certain tearability when being torn, and the paper is not torn.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sealing film, in particular to a paper-plastic sealing film suitable for cold drink blister cups and application thereof. BACKGROUND

[0002] At present, the sealing film of cup products in ice cream market is mainly aluminum-plastic sealing film containing aluminum foil. However, the production of aluminum has high energy consumption and emission. About 13500 degrees of electricity are needed for electrolysis of 1 ton of aluminum, and about 12 tons of carbon dioxide are emitted, which causes great pressure on resources consumption and environment. The aluminum foil in aluminum-plastic sealing film is a non-renewable resource. In order to reduce resource consumption, it is urgent to explore a new renewable sealing film suitable for cold drink blister cups, such as paper-plastic sealing film. At present, there is no application of paper-plastic sealing film replacing aluminum-plastic sealing film suitable for cold drink blister cups. The forming process of cold drink blister cup is different from that of injection molded cup. The cold drink blister cup is formed by secondary processing of thin sheet material, which results in high melting temperature of the blister cup and thin edge and poor flatness. Therefore, the sealing film is required to have high temperature resistance, how to control the flatness of single paper-plastic sealing film, realize automatic film suction and film falling, and how to ensure that the paper-plastic sealing film still has good sealing strength with the blister cup after-35℃ to-45℃ low temperature tunneling are still problems to be solved.

[0003] The prior art CN112852335A injection molded cup and liquid sealing film of coated paper cup and preparation method thereof comprises, from top to bottom, an ink-receiving layer (3), a barrier layer (4) and a heat-sealing layer (5) arranged in sequence and fixed to each other. The composition of the heat-sealing layer (5) comprises, by weight: high density polyethylene 10-20 parts, low density polyethylene 8-15 parts, linear low density polyethylene 25-30 parts, ethylene-methyl acrylate copolymer 5-8 parts, ethylene-vinyl acetate copolymer 8-12 parts, and polyolefin plasticizer 10-15 parts. The sealing film is for injection molded cup and coated paper cup, not for blister cup, and is not a sheet material structure. The flatness of the sealing film is high, and the flatness requirement of the sealing film is different from that of the blister cup. Although the prior art has a certain sealing strength, it does not solve the problems of flatness and good sealing strength of the paper-plastic sealing film with the blister cup after-35℃ to-45℃ low temperature tunneling. SUMMARY

[0004] The present application provides a paper-plastic sealing film suitable for cold drink blister cups to solve the problems of lack of paper-plastic sealing film suitable for cold drink blister cups, flatness and low temperature (-35~-45℃) sealing strength of the paper-plastic sealing film not meeting the requirements of cold drink blister cups. The specific setting of the material and structure of each layer of the paper-plastic sealing film can better match the heat sealing process, realize good flatness, meet the requirements of automatic film suction and film falling, and ensure that the paper-plastic sealing film still has good sealing strength with the blister cup after-35℃ to-45℃ low temperature tunneling.

[0005] Another object of the present application is to provide an application of the paper-plastic sealing film in sealing of cold drink blister cups.

[0006] Still another object of the present application is to provide a sealing process of cold drink blister cups.

[0007] In a first aspect, the present application provides a paper-plastic sealing film suitable for cold drink blister cups, comprising a first polyester film layer, a paper base layer, a second polyester film layer and a polyolefin heat sealing layer arranged in sequence.

[0008] The paper base layer is resistant to high temperature of 220 DEG C or above, has a basis weight of 60 g / m2 or above, a thickness of 50 mu m or above, an oil absorption of 1.1 g / m2 or below, and a moisture content of 6+ / -2%.

[0009] The polyolefin heat sealing layer has a thickness of 40-50 mu m and is prepared from raw materials comprising linear low density polyethylene 20-35 parts by mass, low density polyethylene 15-20 parts by mass, polyolefin copolymer 25-35 parts by mass, ethylene-vinyl acetate copolymer 5-8 parts by mass, and auxiliary agent 0.3-2 parts by mass.

[0010] According to the present application, the paper-plastic sealing film suitable for cold drink blister cups has a second polyester film layer with a thickness of 6-12 mu m.

[0011] According to the present application, the paper-plastic sealing film suitable for cold drink blister cups has a paper base layer with a basis weight of 60-120 g / m 2 2 and a thickness of 50-100 mu m.

[0012] According to the present application, the paper-plastic sealing film suitable for cold drink blister cups has a first polyester film layer with a thickness of 6-12 mu m.

[0013] According to the present application, the paper-plastic sealing film suitable for cold drink blister cups has a first polyester film layer with a printing layer in the inner layer.

[0014] According to the present application, the paper-plastic sealing film suitable for cold drink blister cups has a first polyester film layer, a paper base layer and a second polyester film layer which are compounded by a single-component polyurethane adhesive.

[0015] According to the present application, the paper-plastic sealing film suitable for cold drink blister cups has a single-component polyurethane adhesive with a viscosity of 5000-6000 mPa.s.

[0016] In a second aspect, the present application provides an application of the paper-plastic sealing film suitable for cold drink blister cups in sealing of cold drink blister cups.

[0017] In a third aspect, the application provides a sealing process for cold drink blister cups, which uses the paper-plastic sealing film suitable for cold drink blister cups for heat sealing.

[0018] According to the sealing process for cold drink blister cups, preferably, the heat sealing uses a two-time heat sealing process, wherein the first-time heat sealing process includes that the heat sealing head has a heat sealing area width of 2.5-3 mm, a heat sealing temperature of 195-205 DEG C, a heat sealing pressure of 4.5-6 Bar, and a heat sealing time of 1-1.2 s;

[0019] The second-time heat sealing process includes that the heat sealing head has a heat sealing area width of 2-2.5 mm, a heat sealing temperature of 205-210 DEG C, a heat sealing pressure of 4.5-6 Bar, and a heat sealing time of 0.8-1 s.

[0020] Advantages:

[0021] The application provides a paper-plastic sealing film suitable for cold drink blister cups, which has a specific film layer structure and material, is good in flatness, can realize the same automatic film suction and falling process as the aluminum-plastic sealing film, and still has good sealing strength with the blister cup after passing through a low-temperature tunnel at-35 DEG C to-45 DEG C, meets the sealing requirement of the product, and has a certain tearability when being torn, and the paper is not torn. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to make the content of the application more easily understood, the application is further described in detail below according to specific embodiments of the application and in combination with the drawings.

[0023] Figure 1 It is a material structure schematic diagram of the paper-plastic sealing film, wherein 1 is a first polyester film layer, 2 is a paper base layer, 3 is a second polyester film layer, and 4 is a polyolefin heat sealing layer.

[0024] Figure 2 It is a flatness effect diagram of the paper-plastic sealing film in Example 1.

[0025] Figure 3 It is a tearability effect diagram of the paper-plastic sealing film applied to the cold drink blister cup in Example 4.

[0026] Figure 4 It is a flatness effect diagram of the paper-plastic sealing film in Comparative Example 1.

[0027] Figure 5 It is a tearability effect diagram of the paper-plastic sealing film applied to the cold drink blister cup in Comparative Example 3. DETAILED DESCRIPTION

[0028] The following examples are used to illustrate the present application, but not to limit the scope of the present application. The specific techniques or conditions not indicated in the examples are carried out according to the techniques or conditions described in the literature in the art, or according to the product instructions. The reagents or instruments not indicated by the manufacturer are all conventional products that can be purchased through regular channels.

[0029] In the present application, the raw materials of each layer of the examples and comparative examples are as follows:

[0030] The first and second polyester film layers are derived from conventional PET film (Guofeng, Anhui).

[0031] Paper base layer-1: resistant to high temperature of 220°C and above, basis weight of 60 g / m 2 , thickness of 50 μm, oil absorption of ≤1.1 g / m 2 , moisture content of 6±2%, derived from Hengxu, Zhejiang.

[0032] Paper base layer-2: resistant to high temperature of 220°C and above, basis weight of 90 g / m 2 , thickness of 75 μm, oil absorption of ≤1.1 g / m 2 , moisture content of 6±2%, derived from Hengxu, Zhejiang.

[0033] Paper base layer-3: resistant to high temperature of 220°C and above, basis weight of 120 g / m 2 , thickness of 100 μm, oil absorption of ≤1.1 g / m 2 , moisture content of 6±2%, derived from Hengxu, Zhejiang.

[0034] Paper base layer-4: resistant to high temperature of 220°C and above, basis weight of 40 g / m 2 , thickness of 35 μm, oil absorption of ≤1.1 g / m 2 , moisture content of 6±2%, derived from Hengxu, Zhejiang.

[0035] The polyolefin heat-seal layer is prepared by using the following raw materials:

[0036] 35 parts of linear low density polyethylene, 20 parts of low density polyethylene, 35 parts of polyolefin copolymer, 6 parts of ethylene-vinyl acetate copolymer, and 1 part of auxiliary;

[0037] The specific preparation method is as follows:

[0038] 35 parts of linear low density polyethylene, 20 parts of low density polyethylene, 35 parts of polyolefin copolymer, 6 parts of ethylene-vinyl acetate copolymer, and 1 part of auxiliary are weighed and put into a reaction device, stirred and vacuumed, and a polyolefin heat-seal layer roll film is obtained by co-extrusion.

[0039] The linear low density polyethylene is derived from CNOOC Shell.

[0040] Low density polyethylene is from Sinopec.

[0041] Polyolefin copolymer is a copolymer of two or more monomer olefins, and is from Mitsui, Japan.

[0042] Ethylene-vinyl acetate copolymer is from Dow.

[0043] Unless otherwise specified, the raw materials of the examples and comparative examples of the present application are from the same source.

[0044] In the specific embodiment, the present application provides a paper-plastic sealing film suitable for cold drink blister cups, as shown in the formula (I), comprising a first polyester film layer, a paper base layer, a second polyester film layer and a polyolefin heat sealing layer arranged in sequence. Figure 1 The paper base layer is resistant to high temperature of 220°C or above, has a basis weight of ≥60g / m 2 , a thickness of ≥50μm, an oil absorption of ≤1.1g / m 2 , and a moisture content of 6±2%.

[0045] The polyolefin heat sealing layer has a thickness of 40-50μm and is prepared from raw materials comprising linear low density polyethylene 20-35 parts, low density polyethylene 15-20 parts, polyolefin copolymer 25-35 parts, ethylene-vinyl acetate copolymer 5-8 parts, and auxiliary agent 0.3-2 parts.

[0046] It should be noted that

[0047] In the paper-plastic sealing film mentioned in the present application, the paper base layer has good high temperature resistance, is resistant to high temperature of 220°C or above, has a basis weight of ≥60g / m 2 , a thickness of ≥50μm (tightness ≥1g / cm³), an oil absorption of ≤1.1g / m 2 , and a moisture content of 6±2%, which can effectively prevent the paper in the paper-plastic sealing film from absorbing moisture and deforming, ensure that it has certain flatness and good texture and printing effect, and meet the sealing requirements of cold drink blister cups.

[0048] The high temperature resistance, basis weight, thickness, oil absorption and moisture content of the paper base layer mentioned in the present application can be determined by conventional detection methods, for example, the basis weight is determined according to GB / T451.2, the thickness is determined according to GB / T451.3, the oil absorption is determined according to GB / T29282, and the moisture content is determined according to GB / T462.

[0049] In the paper-plastic sealing film mentioned in the present application, a second polyester film layer is additionally arranged between the paper base layer and the polyolefin heat sealing layer, which can improve the flatness and sealing property of the overall paper-plastic sealing film, and can control the tearing rate to ensure that the paper is not torn after the paper-plastic sealing film is torn open.

[0050] The heat-seal layer of the paper-plastic sealing film mentioned in the present application is also different from the general heat-seal layer. By thickness control and composition control, it is prepared by mixing specific proportions of olefin polymers, which can significantly improve the low-temperature sealing strength, and ensure that the paper-plastic sealing film and the blister cup still have good sealing strength after passing through the low-temperature tunnel of-35°C to-45°C.

[0051] Among them, the polyolefin copolymer mentioned in the present application can be two or more than two olefin monomers in ethylene, 1-butene, 1-octene, which can be derived from Japan Mitsui.

[0052] The VA content of ethylene-vinyl acetate copolymer is 5%-8%, which can be derived from Dow.

[0053] In some embodiments, in order to achieve better flatness and ensure that the paper-plastic sealing film is not torn after tearing, the thickness of the second polyester film layer is further preferred to be 6-12 μm. For example, it can be 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, etc. Point value or range value composed of any.

[0054] In some embodiments, the basis weight of the paper base layer mentioned in the present application can be 60g / m 2 , 90g / m 2 , 120g / m 2 , etc. Point value or range value composed of any, preferably 60-120g / m 2 .

[0055] In some embodiments, the thickness of the paper base layer mentioned in the present application can be 50 μm, 70 μm, 100 μm, etc. Point value or range value composed of any, preferably 50-100 μm.

[0056] In some embodiments, in order to have better paper protection and printing presentation effect, the thickness of the first polyester film layer mentioned in the present application is 6-12 μm. For example, it can be 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, etc. Point value or range value composed of any.

[0057] In some embodiments, in order to meet the needs of practical application, the inner layer of the first polyester film layer mentioned in the present application comprises a printing layer. The printing layer of the present application is preferably printed on the inner layer of the polyester film by using benzene-free and ketone-free low-VOC environmentally friendly ink.

[0058] In some embodiments, in order to realize solvent-free compounding and achieve better compounding effect, the first polyester film layer, the paper base layer and the second polyester film layer mentioned in the present application are compounded by using single-component polyurethane adhesive.

[0059] The second polyester film layer and the polyolefin heat-seal layer are compounded by a two-component polyurethane adhesive.

[0060] In some embodiments, in order to achieve better composite strength, the viscosity of the single-component polyurethane adhesive mentioned in the application is preferably 5000-6000 mPa.s. For example, it can be 5000 mPa.s, 5200 mPa.s, 5400 mPa.s, 5600 mPa.s, 5800 mPa.s, 6000 mPa.s, etc. Point values or range values composed of any.

[0061] In specific embodiments, the paper-plastic sealing film suitable for cold drink blister cups provided by the application is particularly suitable for the packaging and sealing of cold drink blister cup products, and can be widely used in the field of cold drink blister cup sealing and packaging.

[0062] In specific application embodiments, the cold drink blister cup is preferably made of polypropylene material, and the rim width is ≥4 mm, which can ensure a wide enough heat-seal area.

[0063] In specific embodiments, for the paper-plastic sealing film suitable for cold drink blister cups, the application also specifically provides a sealing process for cold drink blister cups.

[0064] In order to achieve better matching application effect, the heat-seal sealing mentioned in the application adopts a two-time heat-seal process, wherein the first heat-seal process includes: the heat-seal head heat-seal area width is 2.5-3 mm, the heat-seal temperature is 195-205℃, the heat-seal pressure is 4.5-6 Bar, and the heat-seal time is 1-1.2 s;

[0065] The second heat-seal process includes: the heat-seal head heat-seal area width is 2-2.5 mm, the heat-seal temperature is 205-210℃, the heat-seal pressure is 4.5-6 Bar, and the heat-seal time is 0.8-1 s.

[0066] Through the matching of specific heat-seal area, heat-seal temperature, heat-seal pressure, and heat-seal time, etc. Process parameters and paper-plastic sealing film, not only can the paper-plastic sealing film and the blister cup still have good sealing strength after the low-temperature tunnel of-35℃ to-45℃, but also have a certain easy-to-tear property when torn, the paper is not torn, the consumer experience is improved, thereby realizing the industrial application of the paper-plastic sealing film on the cold drink blister cup.

[0067] Because the heat-seal melting temperature of the blister cup is relatively high, the application adopts a two-time heat-seal process, the heat-seal melting temperature of the blister cup is relatively high, the first heat-seal is preheating, and the second heat-seal can better realize heat-seal sealing, can solve the problem of false sealing, and further improve the sealing strength.

[0068] The sealing process of the cold drink blister cup mentioned in the present application can specifically and in detail include the following steps:

[0069] 1. Film placement: arrange the paper-plastic sealing film neatly and flatly in the film hopper;

[0070] 2. Film suction and placement: uniformly suction the paper-plastic sealing film from the film hopper one by one through the suction plate, and then place the paper-plastic sealing film suctioned by the suction plate flatly in the mold plate and mold holder to complete automatic film suction and placement;

[0071] 3. First heat sealing: use a full-copper heat sealing head, the heat sealing head has a heat sealing area with a width of 2.5-3 mm, the heat sealing temperature is 195-205℃, the heat sealing pressure is 4.5-6 Bar, and the heat sealing time is 1-1.2 s to complete the first heat sealing;

[0072] 4. Second heat sealing: use a full-copper heat sealing head, the heat sealing head has a heat sealing area with a width of 2-2.5 mm, the heat sealing temperature is 205-210℃, the heat sealing pressure is 4.5-6 Bar, and the heat sealing time is 0.8-1 s to complete the second heat sealing.

[0073] 5. Low-temperature tunnel entry: the product after the second heat sealing enters a low-temperature tunnel with a temperature of-35 to-45℃ to complete freezing.

[0074] Example 1

[0075] A paper-plastic sealing film suitable for cold drink blister cups, as shown in Figure 1 , comprises a first polyester film layer (6μm), a paper base layer-1, a second polyester film layer (12μm), and a polyolefin heat sealing layer (40μm) arranged in sequence.

[0076] The first polyester film layer, the paper base layer, and the second polyester film layer are compounded by a single-component polyurethane adhesive, and the viscosity of the single-component polyurethane adhesive is 5000 mPa.s.

[0077] The second polyester film layer and the polyolefin heat sealing layer are compounded by a two-component polyurethane adhesive.

[0078] Example 2

[0079] A paper-plastic sealing film suitable for cold drink blister cups, as shown in Figure 1 , comprises a first polyester film layer (12μm), a paper base layer-2, a second polyester film layer (6μm), and a polyolefin heat sealing layer (45μm) arranged in sequence.

[0080] The first polyester film layer, the paper base layer, and the second polyester film layer are compounded by a single-component polyurethane adhesive, and the viscosity of the single-component polyurethane adhesive is 5000 mPa.s.

[0081] The second polyester film layer and the polyolefin heat-seal layer are compounded by a two-component polyurethane adhesive.

[0082] Example 3

[0083] A paper-plastic sealing film suitable for cold drink blister cups, as shown in Figure 1 comprises, in sequence, a first polyester film layer (12 μm), a paper base layer-3, a second polyester film layer (6 μm), and a polyolefin heat-seal layer (50 μm).

[0084] The first polyester film layer, the paper base layer, and the second polyester film layer are compounded by a single-component polyurethane adhesive, and the viscosity of the single-component polyurethane adhesive is 5000 mPa.s.

[0085] The second polyester film layer and the polyolefin heat-seal layer are compounded by a two-component polyurethane adhesive.

[0086] Example 4

[0087] A sealing process for cold drink blister cups, comprising the following steps:

[0088] 1. Film arrangement: The paper-plastic sealing film of Example 1 is arranged neatly and placed flat in a film hopper;

[0089] 2. Film suction and film falling: The paper-plastic sealing film is uniformly sucked out from the film hopper one by one by a suction cup, and then the paper-plastic sealing film sucked out by the suction cup is placed flat in a mold plate mold holder, to complete automatic film suction and film falling;

[0090] 3. First heat sealing: A full-copper heat sealing head is used, the heat sealing head has a heat sealing area width of 2.5 mm, a heat sealing temperature of 195℃, a heat sealing pressure of 4.5 Bar, and a heat sealing time of 1 s, to complete first heat sealing;

[0091] 4. Second heat sealing: A full-copper heat sealing head is used, the heat sealing head has a heat sealing area width of 2 mm, a heat sealing temperature of 205℃, a heat sealing pressure of 4.5 Bar, and a heat sealing time of 0.8 s, to complete second heat sealing;

[0092] 5. Low-temperature tunnel: The product after second heat sealing enters a low-temperature tunnel at -35℃ to -45℃, to complete freezing.

[0093] The paper-plastic sealing film of Example 1 has good flatness, as shown in Figure 2 , and can realize automatic film suction and film falling. After passing through the low-temperature tunnel at -35℃ to -45℃, the paper-plastic sealing film and the blister cup still have good sealing strength, and can maintain no air leakage under a negative pressure of -0.04 Mpa for 30 s, meeting the sealing requirement of the product.

[0094] In the application of cold drink blister cups, the paper-plastic sealing film has certain tearability when being torn, and the paper is not torn, as shown inFigure 3 as shown.

[0095] Example 5

[0096] A sealing process of a cold drink blister cup, comprising the following steps:

[0097] 1. Film placement: The paper-plastic sealing film of Example 2 is arranged neatly and placed flat in the film hopper;

[0098] 2. Film suction and film placement: The paper-plastic sealing film is uniformly sucked out from the film hopper one by one by the suction cup, and then the paper-plastic sealing film sucked out by the suction cup is placed flat in the mold plate mold holder, to complete the automatic film suction and film placement;

[0099] 3. First heat sealing: A full-copper heat sealing head is used, the heat sealing head has a heat sealing area width of 2.8 mm, a heat sealing temperature of 200°C, a heat sealing pressure of 5.5 Bar, and a heat sealing time of 1.1 s, to complete the first heat sealing;

[0100] 4. Second heat sealing: A full-copper heat sealing head is used, the heat sealing head has a heat sealing area width of 2.2 mm, a heat sealing temperature of 208°C, a heat sealing pressure of 5.5 Bar, and a heat sealing time of 0.9 s, to complete the second heat sealing;

[0101] 5. Low-temperature tunnel: The product after the second heat sealing enters a low-temperature tunnel at -35°C to -45°C, to complete the freezing.

[0102] The paper-plastic sealing film of Example 2 has good flatness and can realize automatic film suction and film placement. After passing through the low-temperature tunnel at -35°C to -45°C, the paper-plastic sealing film and the blister cup still have good sealing strength, and can maintain no air leakage under -0.04 Mpa negative pressure for 30 s, meeting the sealing requirement of the product.

[0103] In the application of the cold drink blister cup, the paper-plastic sealing film has certain tearability when being torn, and the paper is not torn.

[0104] Example 6

[0105] A sealing process of a cold drink blister cup, comprising the following steps:

[0106] 1. Film placement: The paper-plastic sealing film of Example 3 is arranged neatly and placed flat in the film hopper;

[0107] 2. Film suction and film placement: The paper-plastic sealing film is uniformly sucked out from the film hopper one by one by the suction cup, and then the paper-plastic sealing film sucked out by the suction cup is placed flat in the mold plate mold holder, to complete the automatic film suction and film placement;

[0108] 3. First heat sealing: using a full copper heat sealing head, the heat sealing head heat sealing area width is 3mm, the heat sealing temperature is 205℃, the heat sealing pressure is 6Bar, the heat sealing time is 1.2s, and the first heat sealing is completed;

[0109] 4. Second heat sealing: using a full copper heat sealing head, the heat sealing head heat sealing area width is 2.5mm, the heat sealing temperature is 210℃, the heat sealing pressure is 6Bar, the heat sealing time is 1s, and the second heat sealing is completed;

[0110] 5. Entering a low temperature tunnel: the product after the second heat sealing enters a low temperature tunnel of-35℃ to-45℃, and freezing is completed.

[0111] The paper-plastic sealing film of Example 3 has good flatness and can realize automatic film suction and film falling. After passing through the low temperature tunnel of-35℃ to-45℃, the paper-plastic sealing film and the suction cup still have good sealing strength, can keep no air leakage under-0.04Mpa negative pressure for 30s, and meet the sealing requirement of the product.

[0112] In the application of cold drink suction cups, the paper-plastic sealing film has certain easy tearing when torn, and the paper is not torn.

[0113] Example 7

[0114] A sealing process of a cold drink suction cup, comprising the following steps:

[0115] 1. Film arrangement: arrange the paper-plastic sealing film of Example 3 neatly and place it in the film hopper;

[0116] 2. Film suction and film falling: uniformly suction the paper-plastic sealing film from the film hopper by the suction cup, and then place the paper-plastic sealing film suctioned by the suction cup in the mold plate and mold holder to complete automatic film suction and film falling.

[0117] 3. First heat sealing: using a full copper heat sealing head, the heat sealing head heat sealing area width is 3mm, the heat sealing temperature is 205℃, the heat sealing pressure is 6Bar, the heat sealing time is 1.2s, and the first heat sealing is completed.

[0118] The paper-plastic sealing film of Example 3 has good flatness and can realize automatic film suction and film falling. After passing through the low temperature tunnel of-35℃ to-45℃, the paper-plastic sealing film and the suction cup still have good sealing strength, meet the sealing requirement of the product, but there is false sealing and insufficient sealing strength.

[0119] Comparative Example 1

[0120] A paper-plastic sealing film suitable for cold drink suction cups, comprising a first polyester film layer (6μm), a paper base layer-4, a second polyester film layer (12μm), and a polyolefin heat sealing layer (40μm) arranged in sequence.

[0121] The first polyester film layer, the paper base layer and the second polyester film layer are compounded by a single-component polyurethane adhesive, and the viscosity of the single-component polyurethane adhesive is 5000 mPa.s.

[0122] The paper-plastic sealing film of the comparative example 1 is not flat, and as shown in Figure 4 , automatic film suction and film falling cannot be realized.

[0123] Comparative example 2

[0124] A paper-plastic sealing film suitable for cold drink suction cup, comprising a first polyester film layer (12 μm), a paper base layer-2, a second polyester film layer (6 μm) and a polyolefin heat sealing layer (30 μm) arranged in sequence.

[0125] The first polyester film layer, the paper base layer and the second polyester film layer are compounded by a single-component polyurethane adhesive, and the viscosity of the single-component polyurethane adhesive is 5000 mPa.s.

[0126] The paper-plastic sealing film of the comparative example 2 is applied to the sealing process of the cold drink suction cup, and specifically referring to the sealing process of the cold drink suction cup in the example 5, 18 s of air leakage occurs under-0.04 Mpa negative pressure, and 30 s of air leakage cannot be maintained, the sealing strength is insufficient, and the sealing requirement of the product cannot be met.

[0127] Comparative example 3

[0128] A paper-plastic sealing film suitable for cold drink suction cup, comprising a first polyester film layer (12 μm), a paper base layer-3 and a polyolefin heat sealing layer (50 μm), and the difference from the example 3 is that there is no second polyester film layer.

[0129] The first polyester film layer and the paper base layer are compounded by a single-component polyurethane adhesive, and the viscosity of the single-component polyurethane adhesive is 5000 mPa.s.

[0130] The paper-plastic sealing film of the comparative example 3 is not flat, and after the sealing process of the cold drink suction cup in the example 6, the paper is torn when being torn, as shown in Figure 5 .

[0131] Comparative example 4

[0132] A paper-plastic sealing film suitable for cold drink suction cup, comprising a first polyester film layer (12 μm), a paper base layer-3, a second polyester film layer (6 μm) and a polyolefin heat sealing layer (50 μm). The difference from the example 3 is that the polyolefin heat sealing layer has no ethylene-vinyl acetate copolymer component.

[0133] The first polyester film layer, the paper base layer and the second polyester film layer are compounded by a single-component polyurethane adhesive, and the viscosity of the single-component polyurethane adhesive is 5000 mPa.s.

[0134] The paper plastic sealing film of Comparative Example 4 has good flatness, and after the sealing process of the cold drink blister cup of Reference Example 6 is sealed, the paper is easily torn when it is torn, and the paper is torn.

[0135] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A paper-plastic sealing film suitable for cold drink blister cups, characterized in that, It includes a first polyester film layer, a paper base layer, a second polyester film layer, and a polyolefin heat-sealing layer arranged in sequence; The paper base layer is heat resistant to 220℃ and above, and has a basis weight ≥60g / m³. 2 Thickness ≥ 50 μm, oil absorption ≤ 1.1 g / m 2 The moisture content is 6±2%; The thickness of the polyolefin heat-sealing layer is 40-50 μm, and it is prepared by means of the following components: 20-35 parts of linear low-density polyethylene, 15-20 parts of low-density polyethylene, 25-35 parts of polyolefin copolymer, 5-8 parts of ethylene-vinyl acetate copolymer, and 0.3-2 parts of additives. The thickness of the second polyester film layer is 6~12μm.

2. The paper-plastic sealing film for cold drink blister cups according to claim 1, characterized in that, The basis weight of the paper base layer is 60~120g / m³. 2 The thickness is 50~100μm.

3. The paper-plastic sealing film for cold drink blister cups according to claim 1 or 2, characterized in that, The thickness of the first polyester film layer is 6~12μm.

4. The paper-plastic sealing film for cold drink blister cups according to claim 1 or 2, characterized in that, The inner layer of the first polyester film layer includes a printed layer.

5. The paper-plastic sealing film for cold drink blister cups according to claim 1 or 2, characterized in that, The first polyester film layer, the paper base layer, and the second polyester film layer are bonded together by a one-component polyurethane adhesive.

6. The paper-plastic sealing film for cold drink blister cups according to claim 5, characterized in that, The viscosity of the single-component polyurethane adhesive is 5000~6000 mPa·s.

7. The application of the paper-plastic sealing film according to any one of claims 1 to 6 for sealing cold drink blister cups.

8. A sealing process for a cold drink blister cup, characterized in that, The paper-plastic sealing film suitable for cold drink blister cups as described in any one of claims 1 to 7 is used for heat sealing.

9. The sealing process of the cold drink blister cup according to claim 8, characterized in that, The heat sealing process employs a two-stage heat sealing process, wherein the first stage includes: a heat sealing head with a heat sealing area width of 2.5~3mm, a heat sealing temperature of 195℃~205℃, a heat sealing pressure of 4.5~6Bar, and a heat sealing time of 1~1.2s; The secondary heat sealing process includes: a heat sealing head with a heat sealing area width of 2~2.5mm, a heat sealing temperature of 205℃~210℃, a heat sealing pressure of 4.5~6Bar, and a heat sealing time of 0.8~1s.

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