Five-stage symmetric blanking glue-saving BOPP box sealing adhesive tape and preparation method thereof

Abstract

The present application belongs to the technical field of packaging consumables and functional pressure-sensitive adhesive tape coating manufacturing, and particularly relates to a five-section symmetrical blanking glue-saving BOPP carton sealing adhesive tape and a preparation method thereof. The five-section symmetrical blanking glue-saving BOPP carton sealing adhesive tape comprises, from top to bottom, a pressure-sensitive adhesive layer and a BOPP substrate layer arranged in sequence. The pressure-sensitive adhesive layer comprises a glue-coated area and a glue-free area, and the glue-coated area is obtained by coating pressure-sensitive adhesive. The area of the glue-coated area accounts for 66-69% of the total area of the pressure-sensitive adhesive layer, with the total area of the pressure-sensitive adhesive layer being 100%. The five-section symmetrical blanking glue-saving BOPP carton sealing adhesive tape of the present application sets the glue-coated area and the glue-free area by partitioning, releases the concentrated stress of the adhesive layer by the glue-free area, forms an exhaust passage, effectively reduces the carton packaging breakage rate, forms a bonding area by the glue-coated area, improves the peeling strength between the carton sealing adhesive tape and the product, completely eliminates the problems of hollowing and warping of the adhesive tape, greatly reduces the amount of pressure-sensitive adhesive, and reduces the cost of raw materials and production energy consumption.

Description

Technical Field

[0001] This invention belongs to the field of packaging consumables and functional pressure-sensitive tape coating and manufacturing technology, specifically relating to a five-segment symmetrical white space adhesive-saving BOPP sealing tape and its preparation method. Background Technology

[0002] Currently, BOPP (biaxially oriented polypropylene film) sealing tapes on the market are mainly divided into two categories: full-coat tapes and non-full-coat intermittent tapes.

[0003] The first type is full-coat tape, which uses a full-width coating process, that is, 100% coverage of the BOPP film substrate with environmentally friendly water-soluble acrylic pressure-sensitive adhesive. It can be widely used in express delivery, postal services, e-commerce warehousing, and industrial goods sealing. This traditional product and production process has the following disadvantages:

[0004] (1) Excessive glue consumption, high raw material costs, no blank areas in the fully coated structural substrate, large area of ​​glue in the middle of the tape with no additional bonding gain, only as a filler redundant layer, greatly consuming environmentally friendly water-soluble acrylic pressure-sensitive adhesive raw materials; at the same time, the large amount of glue will lead to an increase in the hot air energy consumption of the drying process, resulting in high overall manufacturing cost per unit product.

[0005] (2) Stress concentration in the adhesive layer leads to a high rate of damage and opening of cardboard boxes. Stacking during logistics transportation, vehicle bumps, and changes in temperature and humidity cause continuous slight deformation of the cardboard boxes. The fully coated adhesive layer has high overall rigidity and no buffering space, so the adhesive layer cannot adapt to the deformation and expansion of the cardboard box, making it very easy for the tape to break, the corners to peel off, and the box to crack. The industry standard for the damage and opening rate of fully coated tape is 2.2% to 2.4%, resulting in huge losses for express delivery companies in terms of claims.

[0006] (3) The sealing of the box is prone to bubbling and hollowing, the adhesion durability is poor, the full coating of adhesive has no air venting channel, when the tape is applied to the carton, the air trapped between the adhesive layer and the cardboard cannot be discharged, and bubbles and local hollowing appear after the finished tape is rolled up and sealed; the adhesion fails at the bubble position, and after a period of storage, natural curling and glue separation occur, and the packaging seal does not meet the standards.

[0007] The second category is existing non-fully coated BOPP sealing tape, which generally has the following defects: (1) Non-full coating tape has no fixed ratio of coating, no standard segment size, mostly random blanking, disorderly and intermittent coating, extremely poor batch consistency, and the glue saving ratio cannot be quantified and is unstable. (2) The non-full coating tape has an asymmetrical structure, and the sealing force is uneven. After transportation vibration and stacking, it is very easy for the edges to curl up, peel off, and break. (3) After the non-full coating tape saves a lot of glue, the bonding performance, temperature resistance and aging resistance are greatly reduced, and it cannot meet the national standard for superior products in the industry. It cannot meet the requirements of long-distance logistics transportation and high and low temperature storage conditions. (4) Non-full coating tapes do not have a matching exclusive drying process. The coating speed is limited to 160m / min and it is difficult to increase the speed. High-speed production is prone to problems such as insufficient curing, uneven thickness of the adhesive layer, surface drying without internal curing, sticking to the roller, and sticking during winding. It is difficult to balance high-speed mass production and finished product qualification rate.

[0008] In summary, there is an urgent need for a new type of tape structure that can reduce adhesive usage, buffer stress, eliminate air bubbles, and be suitable for high-speed mass production, while ensuring that the adhesive performance fully meets the standards. It also needs to be matched with an integrated coating production process. Summary of the Invention

[0009] Based on the above technical background, the main objective of this invention is to provide a five-segment symmetrical white space adhesive-saving BOPP sealing tape and its preparation method, so as to overcome the shortcomings of the prior art, such as high adhesive consumption, high breakage rate, easy bubbling, whitening, poor residual wetness, low production rate, uneven tension of master roll feeding, deviation, edge curling, winding wrinkles, and high production capacity and high consumption.

[0010] To achieve the aforementioned objectives, the technical solution adopted by this invention includes: The first aspect of the present invention is to provide a five-segment symmetrical white space adhesive-saving BOPP sealing tape, wherein the sealing tape has a double-layer composite structure and comprises a pressure-sensitive adhesive layer and a BOPP substrate layer arranged sequentially from top to bottom.

[0011] The thickness ratio of the pressure-sensitive adhesive layer to the BOPP substrate layer is (16-20):27.

[0012] Preferably, the thickness ratio of the pressure-sensitive adhesive layer to the BOPP substrate layer is 18:27.

[0013] The five-segment symmetrical blank space adhesive-saving BOPP sealing tape is made by coating pressure-sensitive adhesive onto the surface of a BOPP substrate layer.

[0014] The pressure-sensitive adhesive layer includes an adhesive-coated area 1 and an adhesive-free area 2, such as Figure 1 As shown, both the glue-coated area 1 and the glue-free area 2 are disposed on the BOPP substrate layer. The glue-coated area is coated with pressure-sensitive adhesive, while the glue-free area is not coated with pressure-sensitive adhesive.

[0015] Preferably, the coated area is coated with environmentally friendly water-soluble acrylic pressure-sensitive adhesive, while the uncoated area is not coated with any material. The environmentally friendly water-soluble acrylic pressure-sensitive adhesive is benzene-free and formaldehyde-free, meeting the environmental protection requirements for food packaging.

[0016] With the total area of ​​the pressure-sensitive adhesive layer being 100%, the area of ​​the adhesive-coated area accounts for 75-85% of the total area of ​​the pressure-sensitive adhesive layer.

[0017] Preferably, with the total area of ​​the pressure-sensitive adhesive layer being 100%, the area of ​​the adhesive coating area accounts for 66-69% of the total area of ​​the pressure-sensitive adhesive layer.

[0018] More preferably, with the total area of ​​the pressure-sensitive adhesive layer being 100%, the area of ​​the adhesive coating area accounts for 32.5% of the total area of ​​the pressure-sensitive adhesive layer.

[0019] Preferably, the adhesive application area includes a left edge adhesive application area, a central main adhesive application area, and a right edge adhesive application area.

[0020] Preferably, the glue-free area includes a breathable white space on the left and a breathable white space on the right.

[0021] More preferably, the glue-coated area and the glue-free area are arranged on the surface of the BOPP substrate layer as follows: The sealing tape is divided into five sections from the left edge to the right edge. These five sections are symmetrically arranged to ensure even stress distribution.

[0022] Along the width of the BOPP substrate layer, five areas are sequentially designated from left to right edge: left edge adhesive application area, left breathable blank area, central main adhesive application area, right breathable blank area, and right edge adhesive application area. Figure 1 As shown.

[0023] The width of the adhesive coating area on the left edge is 4 / 40 to 6 / 40 of the width of the BOPP substrate layer. Its function is to seal the side of the tape and prevent the side from peeling off during transportation and unpacking.

[0024] Preferably, the width of the adhesive coating area on the left edge accounts for 5 / 40 of the width of the BOPP substrate layer.

[0025] The width of the breathable blank area on the left side accounts for 6 / 40 to 7.5 / 40 of the width of the BOPP substrate layer. Its function is to act as a lateral deformation buffer zone to release the concentrated stress in the lateral direction of the adhesive layer.

[0026] Preferably, the width of the left breathable blank area is 6.5 / 40 of the width of the BOPP substrate layer.

[0027] The width of the central main adhesive coating area is 15 / 40 to 20 / 40 of the width of the BOPP substrate layer. The function of the central main adhesive coating area is: the core of the tape bears the bonding area and provides the main sealing adhesive force.

[0028] Preferably, the width of the central main adhesive coating area accounts for 17 / 40 of the width of the BOPP substrate layer.

[0029] The width of the right-side breathable blank area is 6 / 40 to 7.5 / 40 of the width of the BOPP substrate layer. Its main function is to be symmetrical with the left-side breathable blank area and to balance the lateral buffering performance of the tape.

[0030] Preferably, the width of the right-side breathable blank area is 6.5 / 40 of the width of the BOPP substrate layer.

[0031] The width of the adhesive coating area on the right edge accounts for 4 / 40 to 6 / 40 of the width of the BOPP substrate layer. Its main function is to create a symmetrical closed loop with the adhesive coating area on the left edge, so that the adhesive coating areas on the left and right edges can achieve simultaneous sealing on both sides.

[0032] Preferably, the width of the adhesive coating area on the right edge accounts for 5 / 40 of the width of the BOPP substrate layer.

[0033] For example, taking a BOPP substrate layer of 40mm as an example, the widths of the left edge adhesive coating area, the left breathable blank area, the central main adhesive coating area, the right breathable blank area, and the right edge adhesive coating area are: The width of the adhesive coating area on the left edge is 4~6mm.

[0034] Preferably, the width of the adhesive coating area on the left edge is 5mm.

[0035] The width of the breathable blank area on the left is 6 to 7.5 mm.

[0036] Preferably, the width of the left breathable blank area is 6.5mm.

[0037] The width of the main adhesive coating area in the middle is 15~20mm.

[0038] Preferably, the width of the intermediate adhesive coating area is 17 mm.

[0039] The width of the breathable blank area on the right is 6 to 7.5 mm.

[0040] Preferably, the width of the right-side breathable blank area is 6.5mm.

[0041] The width of the adhesive coating area on the right edge is 4-6 mm.

[0042] Preferably, the width of the adhesive coating area on the right edge is 5 mm.

[0043] The main functions of the left and right edge adhesive application areas in this invention are as follows: the two edges of the tape are the most likely to come into contact with air and the most obvious temperature and humidity deformation. The narrow continuous adhesive layer cools and sets faster, which can firmly lock the edge of the BOPP film and counteract the thermal shrinkage deformation of the film. At the same time, the narrow adhesive will not produce extra ineffective bonding. Only the minimum amount of adhesive is needed to complete the edge protection, eliminating common industry problems such as edge curling, edge peeling and edge delamination.

[0044] The purpose of the left and right breathable blank areas is to construct a longitudinally continuous convection airflow channel, discharge drying moisture, and completely remove all ineffective adhesive from the area. The width (6.5 mm) of the left and right breathable blank areas in this invention has been verified through 1600 mm wide-width wind field simulation and is the optimal threshold that balances airflow volume and unit compactness. The breathable blank areas are completely free of adhesive, which on the one hand directly removes all redundant and ineffective adhesive from the area, achieving cost reduction and adhesive saving; on the other hand, the two longitudinal blank areas can form a permanent ventilation channel, and moisture in the oven can be quickly discharged along the blank channels, significantly reducing the wet load of the entire master roll and physically preventing tape bubbling, whitening, and residual moisture.

[0045] The purpose of setting up the central main adhesive application area in this invention is to concentrate all effective bonding and maximize the utilization rate of adhesive. The main function of this area is to concentrate the stress, peel strength, and holding power of the sealing tape in the transverse center area of ​​the tape. The 17mm width has been mechanically tested and just meets the highest level of bonding index of the national standard GB / T 23256. By concentrating all effective adhesive layers in the stress center, the non-stress areas rely on blank areas to remove excess adhesive, thus achieving unchanged bonding performance and a significant reduction in adhesive consumption.

[0046] The adhesive coating area and blanking area of ​​this invention are perfectly symmetrically arranged, ensuring dynamic balance during high-speed feeding of the 1600 mm wide master roll. Asymmetrical adhesive coating can cause inconsistencies in adhesive amount, drying shrinkage, and air pressure on the left and right sides of the tape surface, leading to tape deviation, left-right tension imbalance, and uneven winding, thus affecting the adhesive strength of the tape. This invention adopts a five-segment perfectly symmetrical structure, ensuring completely uniform tension, heat shrinkage, and airflow across the entire 1600 mm master roll, guaranteeing stable operation at a baseline speed of 180 m / min, while also providing a foundation for ultra-high-speed acceleration.

[0047] The invention features a dual buffer system with a left-side and right-side breathable blank area, which simultaneously achieves the triple effects of reducing adhesive usage, relieving stress, and removing air bubbles in the five-segment symmetrical blank BOPP sealing tape. This effectively reduces the breakage rate of the BOPP sealing tape on the product packaging and improves the packaging effect.

[0048] The second aspect of this invention is to provide a method for preparing the five-segment symmetrical white space adhesive-saving BOPP sealing tape described in the first aspect of this invention, the preparation method comprising the following steps: A pressure-sensitive adhesive layer is set on the BOPP substrate layer, and the pressure-sensitive adhesive layer is divided into an adhesive-coated area and an adhesive-free area. Environmentally friendly water-soluble acrylic pressure-sensitive adhesive is applied to the adhesive-coated area, and then dried and cured. The resulting composite tape is cooled and shaped at a constant temperature. Finally, after slitting and winding, a five-segment symmetrical white space adhesive-saving BOPP sealing tape is obtained.

[0049] Preferably, the preparation method includes the following steps: Step 1: Unwind the BOPP substrate, then remove static electricity and double-sided dust to form the BOPP substrate layer; Step 2: Apply the well-stirred pressure-sensitive adhesive onto the BOPP substrate layer; Step 3: Dry and cure the BOPP substrate layer coated with pressure-sensitive adhesive, and cool and shape it at a constant temperature to form a pressure-sensitive adhesive layer on the BOPP substrate layer, including the uncoated area and the coated area. Finally, after slitting and winding, a five-segment symmetrical blank BOPP sealing tape is obtained.

[0050] The steps described above are described in detail below.

[0051] In step 1, the BOPP substrate layer is unwound under constant tension with closed-loop tension control to prevent stretching and deformation of the substrate. The BOPP substrate layer passes through an electrostatic eliminator and a double-sided dust removal brush in sequence to remove dust and static electricity from the film surface and prevent pinholes and missing adhesive defects in the coating.

[0052] In step 2, the well-stirred environmentally friendly water-soluble acrylic pressure-sensitive adhesive is coated onto the BOPP substrate layer using an anilox roller. The surface of the anilox roller is decorated with raised and recessed patterns that precisely match the adhesive paths in the coated and uncoated areas (1:1 ratio). The raised and recessed patterns accurately correspond to the respective coated area 1 and uncoated area 2. The blank areas are free of grooves on the roller body, preventing adhesive buildup and contamination of the blank areas.

[0053] In this invention, the anilox roller is used to apply adhesive to the surface of the BOPP substrate layer, so that the surface of the BOPP substrate layer has a corresponding left edge adhesive application area, a left breathable blank area, a central main adhesive application area, a right breathable blank area, and a right edge adhesive application area, thereby producing a five-segment symmetrical blank adhesive-saving BOPP sealing tape.

[0054] The well-stirred environmentally friendly water-soluble acrylic pressure-sensitive adhesive is applied to the BOPP substrate layer using an anilox roller at a linear speed of 10–180 m / min. The linear speed and roller gap can be adjusted accordingly. By adjusting the linear speed and roller gap, the dry adhesive thickness of the coated area on the BOPP substrate layer surface can be ensured to remain stable within a certain range after curing, guaranteeing uniform thickness across all coated areas.

[0055] In step 3, the drying and curing process uses a segmented heating oven. The BOPP substrate layer coated with environmentally friendly water-soluble acrylic pressure-sensitive adhesive is dried using a multi-stage gradient hot air drying and heating mode. The gradient heating mode used in this invention can avoid stress cracking of the adhesive layer caused by instantaneous high temperature. Low-temperature pre-drying can remove free moisture on the surface, medium-temperature drying can deeply cure the coated area, and high-temperature drying at the end can ensure that the adhesive layer in the coated area is completely cured, avoiding internal undried areas that would affect the bonding performance and adhesion effect of the adhesive layer in the coated area.

[0056] The drying and curing conditions are as follows: the BOPP substrate layer coated with environmentally friendly water-soluble acrylic pressure-sensitive adhesive is passed sequentially through the following drying zones at a linear speed of 160–180 m / min: the drying temperature of the first drying zone is 60–70℃; the drying temperature of the second drying zone is 70–90℃; the drying temperature of the third drying zone is 90–110℃; the drying temperature of the fourth drying zone is 90–110℃; the drying temperature of the fifth drying zone is 100–120℃; the drying temperature of the sixth drying zone is 105–115℃; the drying temperature of the seventh drying zone is 110–130℃; the drying temperature of the eighth drying zone is 115–125℃; the drying temperature of the ninth drying zone is 90–110℃; and the drying temperature of the tenth drying zone is 70–90℃. The length of each drying zone is 4 m.

[0057] Preferably, the drying and curing conditions are as follows: the BOPP substrate layer coated with environmentally friendly water-soluble acrylic pressure-sensitive adhesive is passed sequentially through the following drying zones at a linear speed of 180 m / min: the drying temperature of the first drying zone is 65°C; the drying temperature of the second drying zone is 80°C; the drying temperature of the third drying zone is 100°C; the drying temperature of the fourth drying zone is 100°C; the drying temperature of the fifth drying zone is 110°C; the drying temperature of the sixth drying zone is 110°C; the drying temperature of the seventh drying zone is 120°C; the drying temperature of the eighth drying zone is 120°C; the drying temperature of the ninth drying zone is 100°C; and the drying temperature of the tenth drying zone is 80°C, with each drying zone being 4 m long.

[0058] After drying and curing, the thickness of the adhesive coating area on the BOPP substrate layer is 16–20 μm.

[0059] Preferably, after drying and curing, the thickness of the adhesive coating area on the BOPP substrate layer is 18 μm.

[0060] The obtained composite tape was cooled at a constant temperature of 20-30℃ for 0.07-0.1 min.

[0061] Preferably, the obtained composite tape is cooled at a constant temperature of 25°C for 0.08 min.

[0062] The constant temperature cooling is preferably carried out in a constant temperature cooling channel. Constant temperature cooling can quickly cool the pressure-sensitive adhesive layer, forming a five-segment strip-shaped symmetrical blank adhesive path outline, eliminating residual internal stress from high-temperature curing, improving the flexibility and dimensional stability of the tape, and preventing the adhesive path from deforming and sticking after winding.

[0063] Online real-time inspection: The integrity of the adhesive path on the surface of the five-segment symmetrical white space adhesive-saving BOPP substrate layer is scanned by corresponding machine vision, and the initial tack and adhesive layer thickness of the sealing tape are detected by online sensors, automatically rejecting defective products such as insufficient adhesive, broken adhesive, and overflow adhesive.

[0064] According to the requirements, the sealing tape is cut into standard width rolls of 40mm and 43.7mm; the sealing tape is wound up smoothly with low tension to avoid compression and deformation, resulting in a finished five-segment symmetrical blank BOPP substrate layer.

[0065] The beneficial effects of this invention are as follows: (1) This invention sets the pressure-sensitive adhesive layer into an adhesive-coated area and an adhesive-free area, and applies environmentally friendly water-soluble acrylic pressure-sensitive adhesive to the adhesive-coated area. This significantly reduces the adhesive coverage of BOPP sealing tape, lowering it to 66-69%, and significantly reduces the amount of environmentally friendly water-soluble acrylic pressure-sensitive adhesive used. Compared with the traditional full-coating method, this invention can reduce the amount of environmentally friendly water-soluble acrylic pressure-sensitive adhesive used by 32.5%. It effectively solves the problem of excessive ineffective adhesive use and large amount of glue waste in traditional full-coating tapes. Without reducing the national standard bonding performance of the tape, it can stably achieve a 32.5% saving in pressure-sensitive adhesive usage. At the same time, it can solve the problems of water vapor retention during the drying of 1600mm wide master rolls, bubbling, whitening, and poor residual moisture during high-speed production.

[0066] (2) The double-sided blank glue-free area set longitudinally on the BOPP substrate layer of the present invention serves as the pressure relief structure of the five-segment symmetrical blank glue-saving BOPP sealing tape, which can doubly disperse stress, so that the sealing tape can only undergo slight deformation when squeezed and bumped by the carton, and will not break due to stress concentration; the blank glue-free area of ​​the present invention can form a continuous exhaust channel, and the interlayer air accumulated when the tape is bonded to the cardboard can be completely discharged along the exhaust channel formed by the blank glue-free area, ensuring that the tape is free of air bubbles and voids, making the bonding surface of the tape and the cardboard more tightly bonded, and making the tape of the present invention less prone to natural delamination in long-term storage and high and low temperature environments, greatly improving the reliability of packaging sealing; the left edge glue coating area, the middle main glue coating area, and the right edge glue coating area set longitudinally on the BOPP sealing tape can provide sufficient adhesion for the sealing tape, so that the BOPP sealing tape has high peel strength.

[0067] Actual logistics packaging tests show that the breakage rate of traditional fully coated sealing tape is 2.2% to 2.4%. The sealing tape of this invention, by setting a left edge coating area, a left breathable blank area, a central main coating area, a right breathable blank area, and a right edge coating area, and limiting the width of the above-mentioned coated areas and uncoated areas within a certain range, can reduce the breakage rate of products packaged by the sealing tape of this invention to 1.5% or less, significantly reducing the loss of express delivery companies in terms of claims.

[0068] (3) The initial tack, holding power, 180° peel strength, temperature resistance and aging resistance of the five-segment symmetrical white space glue-saving BOPP sealing tape of the present invention all meet the GB / T 23256-2009 sealing tape industry standard; without the need to replace the sealing machine or adjust the packaging operation process, the five-segment symmetrical white space glue-saving BOPP sealing tape can directly replace the traditional full-coating tape and is suitable for e-commerce warehousing, express delivery, postal parcels, industrial large-item packaging and other scenarios.

[0069] (4) The preparation method of the five-segment symmetrical white space glue-saving BOPP sealing tape described in this invention is simple. It can be put into production on the existing conventional BOPP coating production line by simply replacing the customized engraved anilox roller, without the need for large-scale production line transformation. The integrated continuous process supports high-speed production of up to 180-220m / min. The process parameters are stable and controllable. The yield of finished products is higher than that of traditional full coating process. Moreover, the energy consumption and cost of preparation are reduced. It effectively solves the problems of uneven tension of wide-width master roll, deviation, edge curling, and winding wrinkles, thereby improving the stability of mass production and the yield. Attached Figure Description

[0070] Figure 1 This diagram illustrates the structure of the five-segment symmetrical, white-space, adhesive-saving BOPP sealing tape of the present invention.

[0071] Explanation of icon numbers 1-Glue application area; 2- No glue area. Detailed Implementation

[0072] The present invention will now be described in detail, and its features and advantages will become clearer and more apparent from these descriptions.

[0073] The first aspect of this invention is to provide a five-segment symmetrical, adhesive-saving BOPP sealing tape. The BOPP sealing tape has a double-layer composite structure, comprising, from top to bottom, a pressure-sensitive adhesive layer and a BOPP substrate layer. The pressure-sensitive adhesive layer includes an adhesive-coated area 1 and an adhesive-free area 2, as shown below. Figure 1 As shown, the coated area is obtained by coating with environmentally friendly water-soluble acrylic pressure-sensitive adhesive, while the uncoated area is not coated with any material. Taking the total area of ​​the pressure-sensitive adhesive layer as 100%, the area of ​​the coated area accounts for 66-69% of the total area of ​​the pressure-sensitive adhesive layer. The thickness ratio of the pressure-sensitive adhesive layer to the BOPP substrate layer is 18:27.

[0074] Along the width direction of the BOPP substrate layer, from the left edge to the right edge of the sealing tape, a left edge adhesive application area, a left breathable blank area, a central main adhesive application area, a right breathable blank area, and a right edge adhesive application area are sequentially arranged. The width of the left edge adhesive application area occupies 5 / 40 of the width of the BOPP substrate layer, the width of the left breathable blank area occupies 6.5 / 40 of the width of the BOPP substrate layer, the width of the central main adhesive application area occupies 17 / 40 of the width of the BOPP substrate layer, the width of the right breathable blank area occupies 6.5 / 40 of the width of the BOPP substrate layer, and the width of the right edge adhesive application area occupies 5 / 40 of the width of the BOPP substrate layer.

[0075] A method for preparing a five-segment fixed symmetrical blank adhesive-saving BOPP sealing tape, the method comprising the following steps: Step 1: Unwind the BOPP substrate using constant tension, and then pass the BOPP substrate layer through an electrostatic eliminator and a double-sided dust removal brush in sequence to remove static electricity from the surface of the BOPP substrate layer and remove dust from both sides. Step 2: Apply the well-stirred environmentally friendly water-soluble acrylic pressure-sensitive adhesive onto the BOPP substrate layer using an anilox roller at a linear speed of 10-180 m / min, thus creating a pressure-sensitive adhesive layer on the BOPP substrate layer. This pressure-sensitive adhesive layer includes corresponding coated and uncoated areas, as well as precisely corresponding left edge coated area, left breathable blank area, central main coated area, right breathable blank area, and right edge coated area. The surface of the anilox roller is provided with a raised pattern that matches the adhesive path of the coated and uncoated areas in a 1:1 ratio. The raised pattern precisely corresponds to the corresponding left edge coated area, left breathable blank area, central main coated area, right breathable blank area, and right edge coated area.

[0076] Step 3: Dry and cure the BOPP substrate layer coated with environmentally friendly water-soluble acrylic pressure-sensitive adhesive. The drying and curing conditions are as follows: The BOPP substrate layer coated with environmentally friendly water-soluble acrylic pressure-sensitive adhesive is passed sequentially through the following drying zones at a linear speed of 180 m / min: Drying temperature of drying zone 1: 60-70℃; Drying temperature of drying zone 2: 70-90℃; Drying temperature of drying zone 3: 90-110℃; Drying temperature of drying zone 4: 90-110℃; Drying temperature of drying zone 5: 100-120℃; Drying temperature of drying zone 6: 105-115℃; Drying temperature of drying zone 7: 110-130℃; Drying temperature of drying zone 8: 115-125℃; Drying temperature of drying zone 9: 90-110℃; Drying temperature of drying zone 10: 70-90℃. The length of each drying zone is 4 m.

[0077] The obtained composite tape is cooled and set at 20-30℃ for 0.07-0.1 min, and finally slit and rolled up to obtain non-fully coated BOPP sealing tape.

[0078] Example The present invention is further illustrated by specific examples below. These embodiments are only for illustrating the present invention and are not intended to limit the scope of the present invention.

[0079] Example 1 A five-segment symmetrical, adhesive-saving BOPP sealing tape is disclosed. The BOPP sealing tape has a double-layer composite structure, comprising a pressure-sensitive adhesive layer and a BOPP substrate layer arranged sequentially from top to bottom. The pressure-sensitive adhesive layer includes an adhesive-coated area and an adhesive-free area. The adhesive-coated area is coated with environmentally friendly water-soluble acrylic pressure-sensitive adhesive, while the adhesive-free area is left uncoated. Taking the total area of ​​the pressure-sensitive adhesive layer as 100%, the area of ​​the adhesive-coated area accounts for 67.5% of the total area of ​​the pressure-sensitive adhesive layer.

[0080] Along the width direction of the BOPP substrate layer, from the left edge to the right edge of the sealing tape, a left edge adhesive application area, a left breathable blank area, a central main adhesive application area, a right breathable blank area, and a right edge adhesive application area are sequentially arranged. Taking a BOPP substrate layer thickness of 40mm as an example, the width of the left edge adhesive application area is 5mm, the width of the left breathable blank area is 6.5mm, the width of the central adhesive application area is 17mm, the width of the right breathable blank area is 6.5mm, and the width of the right edge adhesive application area is 5mm.

[0081] A method for preparing a five-segment symmetrical, white-space, adhesive-saving BOPP sealing tape, the method comprising the following steps: Step 1: Unwind the 27μm thick BOPP substrate with constant tension, and then pass the BOPP substrate layer through an electrostatic eliminator and a double-sided dust removal brush in sequence to remove static electricity from the surface of the BOPP substrate layer and remove dust from both sides. Step 2: Apply the well-stirred environmentally friendly water-soluble acrylic pressure-sensitive adhesive to the BOPP substrate layer using an anilox roller at a linear speed of 180 m / min, thus creating a pressure-sensitive adhesive layer on the BOPP substrate layer. This pressure-sensitive adhesive layer includes corresponding coated and uncoated areas, as well as precisely corresponding left edge coated area, left breathable blank area, central main coated area, right breathable blank area, and right edge coated area. The surface of the anilox roller is provided with a raised pattern that matches the adhesive path of the coated and uncoated areas in a 1:1 ratio. The raised pattern precisely corresponds to the corresponding left edge coated area, left breathable blank area, central main coated area, right breathable blank area, and right edge coated area.

[0082] Step 3: Dry and cure the BOPP substrate layer coated with environmentally friendly water-soluble acrylic pressure-sensitive adhesive. The drying and curing conditions are as follows: the BOPP substrate layer coated with environmentally friendly water-soluble acrylic pressure-sensitive adhesive is passed sequentially through a segmented heating oven at a linear speed of 180 m / min. The temperatures of each segment of the heating oven are as follows: Segment 1: 65℃; Segment 2: 80℃; Segment 3: 100℃; Segment 4: 100℃; Segment 5: 110℃; Segment 6: 110℃; Segment 7: 120℃; Segment 8: 120℃; Segment 9: 100℃; Segment 10: 80℃. After drying and curing, the length of each segment of the heating oven is 4 m, and the thickness of the adhesive coating area on the BOPP substrate layer is 18 μm.

[0083] The obtained composite tape was cooled and shaped at 25°C for 0.08 minutes. Finally, it was slit and rolled up to obtain a five-segment fixed symmetrical blank adhesive-saving BOPP sealing tape.

[0084] Example 2 A five-segment symmetrical white space adhesive-saving BOPP sealing tape is disclosed. The BOPP sealing tape is similar to the BOPP sealing tape described in Example 1, except that, based on a BOPP substrate layer thickness of 43.7mm, the width of the adhesive coating area on the left edge is 5.5mm, the width of the breathable white space on the left edge is 7.1mm, the width of the adhesive coating area in the middle is 18.5mm, the width of the breathable white space on the right edge is 7.1mm, and the width of the adhesive coating area on the right edge is 5.5mm.

[0085] Comparative Example Comparative Example 1 A full-coat BOPP sealing tape, wherein the BOPP sealing tape has a double-layer composite structure, and the sealing tape includes a pressure-sensitive adhesive layer and a BOPP substrate layer arranged sequentially from top to bottom. The pressure-sensitive adhesive layer is obtained by uniformly coating environmentally friendly water-soluble acrylic pressure-sensitive adhesive on the BOPP substrate layer. Taking the total area of ​​the pressure-sensitive adhesive layer as 100%, the area of ​​the coated area accounts for 100% of the total area of ​​the pressure-sensitive adhesive layer.

[0086] Comparative Example 2 The non-full-coat BOPP sealing tape was prepared in a manner similar to that in Example 1, except that in step 3, the drying and curing conditions were as follows: the BOPP substrate layer coated with environmentally friendly water-soluble acrylic pressure-sensitive adhesive was passed sequentially through a segmented heating oven at a linear speed of 180 m / min. The temperatures of each segment of the heating oven were as follows: segment 1: 100°C; segment 2: 100°C; segment 3: 100°C; segment 4: 100°C; segment 5: 100°C; segment 6: 100°C; segment 7: 100°C; segment 8: 100°C; segment 9: 100°C; segment 10: 100°C. After drying and curing, the length of each segment of the heating oven was 400 cm, and the thickness of the adhesive coating area on the BOPP substrate layer was 18 μm.

[0087] Experimental Example Experiment Example 1 Performance Test The initial tack, holding power, 180° peel strength, temperature resistance, and aging resistance of the five-segment symmetrical adhesive-saving BOPP sealing tapes prepared in Examples 1-2 and Comparative Examples 1-2 were tested respectively. The test standards for each index were as follows: the initial tack test standard was GB / T 4852-2002 "Test Method for Initial Tack of Pressure-Sensitive Adhesive Tapes (Rolling Ball Method)"; the holding power test standard was GB / T 4851-2014 "Test Method for Holding Power of Pressure-Sensitive Adhesive Tapes" (using a 1kg weight to suspend the sample and record the time it takes for the sample to fall off the steel plate; unit: h); the 180° peel strength test standard was GB / T 2790-2024 "Test Method for 180° Peel Strength of Adhesives"; the high temperature resistance test standard was GB / T 23256-2009 Appendix High Temperature Treatment (observing sample slippage, glue overflow, and debonding at 65℃ for 72h); and the low temperature resistance test standard was GB / T Appendix 23256-2009 Low-temperature treatment (72h at -15℃, observe whether the tape is brittle or the adhesive layer fails), the test standard for aging resistance is GB / T 16422.3-2014 "Plastics Laboratory Light Source Exposure Tests Part 3: Fluorescent Ultraviolet Lamp" (using UV-313 for 500h ultraviolet aging, after aging, retest the peel strength at 180°, and calculate the strength retention rate (%)). The test results are shown in Table 1.

[0088] Table 1

[0089] As can be seen from Table 1, the five-segment symmetrical adhesive-saving BOPP sealing tapes prepared in Examples 1 and 2 have high initial tack and holding power, high 180° peel strength, and high resistance to high temperature, low temperature and aging.

[0090] Experiment Example 2: Packaging Test Failure Rate The products were packaged using the five-segment symmetrical, adhesive-saving BOPP sealing tape prepared in Examples 1-2 and Comparative Examples 1-2, respectively, and the product packaging breakage rate was tested. The test method was as follows: 1. Preparation 1) Samples: 30 cartons of the same specifications for the five-segment tape and ordinary full-coat tape to be tested (3 / 5 / 8 kg counterweight, 10 cartons of each). 2) Pretreatment: 23℃, 50% humidity, stand for 24 hours; 3) Fall height: (3Kg) = 100 cm, (3~5kg) = 90 cm, (5~8 kg) = 82 cm.

[0091] 2. Test Procedure 1) Use a uniform one-line sealing method, with each group of cartons dropped sequentially from 5 positions (front, side, long edge, short edge, and corner). 2) Optional: high and low temperature cycling, vibration and bump testing, and drop testing after the test.

[0092] 3. Damage assessment (classifying as damaged) Tape broke, entire sheet came off, seal cracked, and the length of the adhesive failure exceeded 5%.

[0093] Slight edge warping, but the indentation is deemed acceptable.

[0094] 4. Breakage Rate Formula Damage rate = Number of damaged boxes ÷ Total number of boxes × 100%.

[0095] 5. Peel strength ≥ 3.0 N / 25 mm; weight suspension test shows no slippage or detachment.

[0096] The test results are shown in Table 2.

[0097] Table 2

[0098] As shown in Table 2, the breakage rate of the sealing tape products described in Examples 1 and 2 is below 1.5%, while the breakage rate of the sealing tape products described in Comparative Examples 1 and 2 is above 2.3%. These results indicate that the five-segment symmetrical, white-space, adhesive-saving BOPP sealing tape of this invention results in a low breakage rate and significantly better sealing effect than the fully coated BOPP sealing tape.

[0099] Compared with Example 1, Comparative Example 2 used a uniform drying and curing temperature of 100℃ for drying and curing. The breakage rate of the sealing tape product prepared in Comparative Example 2 was significantly better than that of the sealing tape product prepared in Example 1. These results indicate that in the preparation process of the five-segment symmetrical blank adhesive-saving BOPP sealing tape of the present invention, the drying and curing temperature and method have a significant impact on the breakage rate of the sealing tape product. Only by using the gradient heating drying method described in this invention can the breakage rate of the five-segment symmetrical blank adhesive-saving BOPP sealing tape of the present invention be reduced, and the sealing effect of the product improved.

[0100] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

Claims

1. A five-segment symmetrical, adhesive-saving BOPP sealing tape, characterized in that, The five-segment symmetrical white space adhesive-saving BOPP sealing tape includes, from top to bottom, a pressure-sensitive adhesive layer and a BOPP substrate layer arranged sequentially. The pressure-sensitive adhesive layer includes an adhesive-coated area and an adhesive-free area, both of which are disposed on the BOPP substrate layer, and the adhesive-coated area is coated with pressure-sensitive adhesive. With the total area of ​​the pressure-sensitive adhesive layer being 100%, the area of ​​the adhesive-coated area accounts for 66-69% of the total area of ​​the pressure-sensitive adhesive layer.

2. The five-segment symmetrical, adhesive-saving BOPP sealing tape according to claim 1, characterized in that, The ratio of the thickness of the pressure-sensitive adhesive layer to the thickness of the BOPP substrate layer is (16-20):27; The pressure-sensitive adhesive is an environmentally friendly water-soluble acrylic pressure-sensitive adhesive.

3. The five-segment symmetrical BOPP sealing tape with blank space as described in claim 1, characterized in that, Along the width direction of the BOPP substrate layer, from left to right, there are a left edge adhesive coating area, a left breathable blank area, a central main adhesive coating area, a right breathable blank area, and a right edge adhesive coating area. The left edge adhesive coating area, left breathable blank area, central main adhesive coating area, right breathable blank area, and right edge adhesive coating area are symmetrically arranged along the width direction of the five-segment symmetrical blank adhesive-saving BOPP substrate layer.

4. The five-segment symmetrical, adhesive-saving BOPP sealing tape according to claim 3, characterized in that, The width of the left edge adhesive coating area is 4 / 40 to 6 / 40 of the width of the BOPP substrate layer; and / or, the width of the left breathable blank area is 6 / 40 to 7.5 / 40 of the width of the BOPP substrate layer; and / or, the width of the central main adhesive coating area is 15 / 40 to 20 / 40 of the width of the BOPP substrate layer; and / or, the width of the right breathable blank area is 6 / 40 to 7.5 / 40 of the width of the BOPP substrate layer; and / or, the width of the right edge adhesive coating area is 4 / 40 to 6 / 40 of the width of the BOPP substrate layer.

5. A method for preparing the five-segment symmetrical, adhesive-saving BOPP sealing tape as described in claim 1, characterized in that, The preparation method includes the following steps: Step 1: Unwind the BOPP substrate, then remove static electricity and double-sided dust to form the BOPP substrate layer; Step 2: Apply the well-stirred pressure-sensitive adhesive onto the BOPP substrate layer; Step 3: Dry and cure the BOPP substrate layer coated with pressure-sensitive adhesive, and cool and shape it at a constant temperature to form a pressure-sensitive adhesive layer on the BOPP substrate layer, including the adhesive-free area and the adhesive-coated area. Finally, after slitting and winding the finished product, a five-segment fixed symmetrical blank adhesive-saving BOPP sealing tape is obtained.

6. The preparation method according to claim 5, characterized in that, In step 3, The drying and curing conditions are as follows: the BOPP substrate layer coated with pressure-sensitive adhesive is passed sequentially through the following drying zones at a linear speed of 160-180 m / min: the drying temperature of the first drying zone is 60-70℃; the drying temperature of the second drying zone is 70-90℃; the drying temperature of the third drying zone is 90-110℃; the drying temperature of the fourth drying zone is 90-110℃; the drying temperature of the fifth drying zone is 100-120℃; the drying temperature of the sixth drying zone is 105-115℃; the drying temperature of the seventh drying zone is 110-130℃; the drying temperature of the eighth drying zone is 115-125℃; the drying temperature of the ninth drying zone is 90-110℃; and the drying temperature of the tenth drying zone is 70-90℃. The length of each drying zone is 4 m.

7. The preparation method according to claim 5, characterized in that, In step 3, After drying and curing, the thickness of the adhesive coating area on the BOPP substrate layer is 17–19 μm.

8. The preparation method according to claim 5, characterized in that, In step 3, The resulting composite tape was cooled at a constant temperature of 20–30°C for 0.08 min.

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