A BOPP tape with oxidative color change at fracture and preparation method thereof

Abstract

The present invention relates to the field of adhesive tapes, and in particular to a BOPP adhesive tape with oxidative discoloration at a fracture and a preparation method thereof, the preparation method comprising: mixing an acrylic emulsion and an organic photochromic material to prepare a photosensitive discoloration emulsion; preparing a pressure-sensitive adhesive; sequentially coating a photosensitive discoloration emulsion and a pressure-sensitive adhesive on a BOPP biaxially oriented polypropylene film to form a discoloration layer and an adhesive layer respectively to prepare the adhesive tape, and rolling the tape up. The adhesive tape of the present invention is endowed with a discoloration function by arranging a discoloration layer between the adhesive layer and the base layer; both sides of the discoloration layer can be treated to be opaque to achieve the technical effect that the adhesive tape only changes color at the cut; in order to improve the stability of its discoloration, chitosan methacrylate is added to improve the tensile effect.

Description

Technical Field

[0001] The invention relates to the field of adhesive tapes, and in particular to a BOPP adhesive tape with oxidative color change at fracture and a preparation method thereof. Background Art

[0002] BOPP tape is based on BOPP biaxially oriented polypropylene film, which is heated and evenly coated with pressure-sensitive adhesive latex to form an adhesive layer ranging from 8μm to 28μm. It is suitable for sealing goods in warehouses, shipping containers, and preventing goods from being stolen or illegally opened. We supply neutral and personalized sealing tapes in up to 6 colors and different sizes.

[0003] In some personalized application scenarios, there is a requirement for the color change of BOPP tape; the BOPP tape on the market cannot meet the personalized requirements for color change. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a BOPP tape with an oxidatively discolored fracture surface, wherein a discoloring layer is arranged between the adhesive layer and the base layer to achieve the effect that the fracture surface can be discolored;

[0006] Correspondingly, the present invention also provides a BOPP tape with oxidatively discolored fracture surface obtained by the above-mentioned preparation method.

[0007] (II) Technical solution

[0008] In order to achieve the above object, the main technical solutions adopted by the present invention include:

[0009] In a first aspect, the present invention provides a method for preparing a BOPP tape with an oxidatively discolored fracture, comprising the following steps:

[0010] S1 Preparation of photochromic emulsion: acrylic emulsion and organic photochromic material are mixed to prepare photochromic emulsion;

[0011] S2 Preparation of pressure-sensitive adhesive;

[0012] S3 sequentially coats a photochromic emulsion and a pressure-sensitive adhesive on a BOPP biaxially oriented polypropylene film to form a color-changing layer and an adhesive layer respectively to obtain the adhesive tape, and then rolls it up.

[0013] The inner layer of the BOPP biaxially oriented polypropylene film and the space between the color-changing layer and the adhesive layer are treated to be opaque so that the color changes only at the fracture. Specifically, a light-shielding layer is provided.

[0014] Optionally, the organic photochromic material is a spiropyran dye, and the mass ratio of the acrylic emulsion to the organic photochromic material is 80-90:2-3.

[0015] Optionally, since the color-changing layer is in a stretched state, the stability of its photosensitive color change is affected, in order to improve its tensile performance, the organic photochromic material is further added with chitosan methacrylate and acrylic emulsion in a mass ratio of 10-20:80-90;

[0016] The preparation of the chitosan methacrylate comprises the following steps: dissolving 10-15 parts of chitosan in an acetic acid aqueous solution, heating to 80-85° C., sequentially adding 100-110 parts of methacrylate, 1-3 parts of vinyl triisopropoxy silicon, and 0.4-0.6 parts of potassium persulfate, and then heating to 85-92° C. to react and obtain the chitosan methacrylate.

[0017] Optionally, the winding process in step S3 adopts an automatic winding mechanism, and the automatic winding mechanism includes an empty roller track, a vertical lifting track and a full roller track that are arranged in parallel and at intervals for guiding the core shafts at both ends of the winding roller; the two ends of the core shaft extend outward from the track surface respectively; the empty roller track is inclined downward, and a plurality of first stop blocks that can moveably stop the core shaft are arranged at intervals along the length direction of the empty roller track on the support surface; the lower end of the vertical lifting track is connected and connected with one side of the lower end of the empty roller track; a vertical push telescopic rod is arranged outside the track surface below the vertical lifting track; a first arc-shaped supporting plate is arranged at the upper end of the vertical push telescopic rod; the first arc-shaped supporting plate lifts the core shaft from the outside of the track surface of the vertical lifting track to lift the empty winding roller to the top of the vertical lifting track; a first rotation limiting arc portion is arranged on the circumference of the core shaft at the top of the vertical lifting track; a driving gear is arranged outside the track surface at the top of the vertical lifting track; a gear ring is arranged on the outer circumferential surface of the core shaft corresponding to the driving gear; the vertical push telescopic rod pushes the winding roller vertically When it reaches the top of the vertical lifting track, the gear ring just meshes with the driving gear; one end of the full roller track is connected and communicated with the other side of the vertical lifting track, and the connection is the position below the top of the vertical lifting track; the full roller track is first tilted upward from one end of the connection with the vertical lifting track to the other end to form an inclined rising track, and then tilted downward to form an inclined descending track; the inclined rising track and the inclined descending track are smoothly connected and connected; corresponding to the direction of the inclined rising track, an oblique push telescopic rod is arranged outside the track surface of one side of the vertical lifting track; the outer end of the oblique push telescopic rod is arranged with a second arc-shaped supporting plate; the second arc-shaped supporting plate pushes the core shaft from the track surface of the vertical lifting track and the oblique rising track to make the full roller with the winding completed enter the oblique rising track; the first arc-shaped supporting plate and the second arc-shaped supporting plate are staggered in front and back positions; the position of the third rotation limiting arc portion is lower than the top position of the vertical lifting track so that the empty winding roller at the top of the vertical lifting track can support the tape between the full winding roller located at the third rotation limiting arc portion and the tape feeding direction.

[0018] Optionally, an extrusion guide cutting mechanism is also arranged directly above the vertical lifting track; the extrusion guide cutting mechanism includes a cutting telescopic rod, an extrusion guide plate vertically fixed at the lower end of the cutting telescopic rod, and a cutting blade; the extrusion guide plate includes an arc panel arranged corresponding to the arc of the diameter of the tape roll completed by winding up, and a deformable extrusion plate connected to the end of the extrusion guide plate close to the inclined descending track; the cutting blade is connected to the end of the deformable extrusion plate close to the inclined descending track; the deformable extrusion plate includes an elastic insulating plate arranged horizontally and located in the middle, and a piezoelectric ceramic plate attached to the upper and lower surfaces of the elastic insulating plate; under the control of the electric field, the upper piezoelectric ceramic plate is extended and the lower piezoelectric ceramic plate is shortened, so that the piezoelectric ceramic plate can be driven to bend into an arc surface attached to the outer circumference of the tape roll; when the piezoelectric ceramic plate is bent and attached to the tape roll, it drives the cutting blade to deflect downward and cut the tape.

[0019] Optionally, a second rotation limiting arc portion is provided at the bottom end of the vertical lifting track corresponding to the circumference of the core shaft.

[0020] Optionally, the end of the inclined descending track is open, and the track support surface extends toward the end, and the extended portion is provided with a third rotation limiting arc portion and a second stop block.

[0021] Optionally, a plurality of through holes are provided on the support surface of the empty roller track corresponding to the first stop block, through which the first stop block can pass; and the first stop block is independently driven to move by the stop telescopic rod.

[0022] The winding method of the automatic winding mechanism comprises the following steps:

[0023] ① The stop telescopic rod at the bottom drives the corresponding first stop block to move downward, so that the upper end surface of the first stop block is flush with the support surface of the empty roller track, so that the empty winding roller stopped by the first stop block rolls downward to the second rotation limit arc surface of the vertical lifting track; then the stop telescopic rod drives the bottom first stop block to lift to the stop position extending into the empty roller track; then the stop telescopic rod adjacent to the stop telescopic rod repeats the action of the stop telescopic rod in turn to make all the empty rollers descend one stop position in turn;

[0024] ② Push the telescopic rod vertically to lift the empty winding roller to the top of the vertical lifting track, so that the gear ring on the mandrel engages with the driving gear, and the driving gear drives the winding roller to rotate and rewind;

[0025] ③ When the winding is about to be completed, the vertical push telescopic rod drives the winding roller to descend to the corresponding entrance position of the inclined ascending track. When it descends to this position, the inclined push telescopic rod just contacts the core shaft to push the winding roller to enter and move along the inclined ascending track to the intersection with the inclined descending track and stop. At this time, the vertical push telescopic rod continues to move down to the bottom of the vertical lifting track; the winding roller rolls along the inclined descending track to the third rotation limit arc portion under the action of gravity and inertia; in this process, the moving distance of the winding roller on the full roller track automatically compensates for the continuous feeding amount of the tape;

[0026] ④ While the oblique telescopic rod pushes the winding roller, the vertical telescopic rod that has been lowered to the initial position lifts the second empty winding roller that enters the second rotation limit arc panel to the top of the vertical lifting track; before the second winding roller is lifted to the top of the vertical lifting track, the first winding roller has not yet rolled to the third rotation limit arc portion;

[0027] ⑤ While step ④ is being performed, the cutting telescopic rod drives the extrusion guide plate to move downward. First, the arc panel contacts the tape supported on the empty winding roller at the top of the vertical lifting track, and extrude and guide the tape along the surface of the winding roller, so that the contact between the tape and the surface of the winding roller changes from line contact to surface contact; at the same time, the external electric field is used to control the deformed extrusion plate to bend downward, further increasing the surface contact area between the tape and the surface of the winding roller. At the same time, the deformed extrusion plate drives the cutting blade to deflect downward during the outward bending process to cut the tape; at this time, the tape of the full-rolled winding roller located on the third rotation limiting arc portion is cut, and the tape on the cut side is completely rolled up under the inertial rotation of the full-rolled winding roller; the tape on the other side is squeezed by the extrusion guide plate and adhered to the winding roller at the top of the vertical lifting track for a new round of winding.

[0028] In a second aspect, the present invention further provides a BOPP tape having an oxidatively discolored fracture surface obtained by the preparation method in any of the above schemes.

[0029] (III) Beneficial effects

[0030] The beneficial effects of the present invention are:

[0031] 1. The adhesive tape of the present invention has a color-changing function by arranging a color-changing layer between the adhesive layer and the base layer; the color-changing layer can be treated to be opaque on both sides to achieve the technical effect that the adhesive tape changes color only at the incision; in order to improve the color-changing stability, chitosan methacrylate is added to improve the tensile effect and the color-changing stability.

[0032] 2. The automatic winding mechanism of the present invention utilizes an empty roller track, a vertical lifting track and a full roller track to automatically feed rollers and switch between empty rollers and full rollers, and the switching process will not affect the feeding of the tape at the original speed, thereby maintaining the continuity and uniformity of tape production and significantly improving the efficiency of tape production; and utilizes an extrusion guide cutting mechanism to cut the tape while changing the roller, and at the same time ensure that the broken part of the tape adheres stably to the new empty roller, so that the tape can be seamlessly switched to be wound on the new roller, and the entire process does not require manual operation of changing rollers and adhering tapes, so the efficiency is extremely high and stable, and both the production efficiency and the stability of the tape winding quality are significantly improved.

[0033] 3. The automatic winding mechanism of the present invention can realize the feeding of the empty roller to the vertical lifting track in sequence according to the control requirements by using the simple action changes of the stop telescopic rod and the first stop block, thereby ensuring the continuous automatic replenishment of the empty roller; the structure and control program requirements are extremely simple, the operation is relatively stable, and the failure rate is low; the empty roller can be simply and quickly lifted to the top of the vertical lifting track by using the vertical push telescopic rod, and the gear ring on the core shaft is engaged with the external driving gear, so that the empty roller can be directly, quickly and stably driven to rotate for winding, and the position characteristics of the vertical lifting track and the inclined lifting track and The oblique push telescopic rod cleverly utilizes the intersection of the two tracks to achieve seamless switching of the push rod and change of the moving direction of the winding roller, so that the winding roller that is about to be wound up moves to the inclined ascending track, and utilizes the angular relationship between the inclined ascending track and the inclined descending track to make the winding roller automatically fall on the inclined descending track, and roll to the third rotation limit arc portion under the action of gravity; and the movement process of the winding roller is cleverly utilized to compensate for the feeding amount of the tape during this period, so as to keep the tape straight, and at the same time use this period of time to complete the action of lifting a new empty roller to the top of the vertical lifting track for roller replacement; so that the new The empty roller supports the adhesive tape to contact with the adhesive tape, and at the same time, the line contact between the adhesive tape and the empty roller is directly converted into surface contact by the extrusion guide cutting mechanism, thereby increasing the adhesion area between the adhesive tape and the empty roller and improving the stability and accuracy when the empty roller is wound; and the extrusion guide cutting mechanism adopts a deformable extrusion plate, and the deformable extrusion plate is bent by the characteristics of piezoelectric ceramics, so that the adhesive tape can be adhered to the empty roller with a large area when it contacts the empty roller without interfering with the adhesive tape during lifting and lowering; and the bending process of the deformable pressure plate is used to automatically realize the deflection of the cutting blade, so as to accurately and cleanly cut. The tape is cut while ensuring that the cut tape can achieve large-area contact and adhesion with the surface of the empty roller when the tape is cut, so as to prevent the tape from detaching from the surface of the empty roller and being unable to be reeled up; and this design not only makes the cutting process of the cutting blade accurate and crisp, but also ensures that the cutting blade will not damage the tape when the deformed pressure plate is not bent. The entire automatic reeling mechanism utilizes a simple but stable mechanism, and realizes multiple technical effects at the same time, cleverly realizing operations such as automatic empty roller feeding, automatic switching between empty roller and full roller, and automatic tape cutting, which can significantly improve the tape production efficiency and reduce time and labor costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a process flow chart of the present invention;

[0035] Figure 2 This is a schematic diagram of the automatic winding mechanism of the present invention in step ①;

[0036] Figure 3 It is a schematic diagram of the automatic winding mechanism of the present invention when the winding roller is lifted to the top of the vertical lifting track in step ②;

[0037] Figure 4 This is a schematic diagram of the automatic winding mechanism of the present invention when winding is about to be completed in step ②;

[0038] Figure 5 It is a schematic diagram of the automatic winding mechanism of the present invention when the winding roller descends to the inclined rail opening in step ③;

[0039] Figure 6 It is a schematic diagram of the automatic winding mechanism of the present invention when the winding roller is pushed to the end section of the inclined ascending track in step ③;

[0040] Figure 7 It is a schematic diagram of the automatic winding mechanism of the present invention when an empty roller is lifted to the top in step ④;

[0041] Figure 8 It is a schematic diagram of the automatic winding mechanism of the present invention squeezing and guiding the cutting mechanism to squeeze and cut the tape in step ⑤;

[0042] Fig. 9 It is a schematic diagram of the automatic winding mechanism of the present invention, in which the second winding roller continues to wind after the adhesive tape is cut in step ⑤;

[0043] Fig.10 It is a schematic diagram of the deformed extrusion plate and the cutting blade of the present invention in a normal state;

[0044] Fig.11 It is a schematic diagram of the deformed extrusion plate and the cutting blade of the present invention in a bending extrusion guiding state;

[0045] Fig.12 It is a schematic structural diagram of the coating device of the present invention;

[0046] Fig.13 It is a structural schematic diagram of the power push rod of the present invention;

[0047] Fig.14 It is a schematic structural diagram of the piezoelectric deformation plate of the present invention.

[0048] 6. Winding roller; 61. Mandrel; 7. Empty roller track; 71. First stop block; 72. Through hole; 73. Stop telescopic rod; 8. Vertical lifting track; 81. Vertical push telescopic rod; 82. First arc-shaped support plate; 83. First rotation limit arc portion; 84. Driving gear; 85. Second rotation limit arc portion; 9. Full roller track; 91. Oblique rising track; 92. Oblique descending track; 93. Oblique push telescopic rod; 94. Second arc-shaped support plate; 95. Third rotation limit arc portion; 96. Second stop block; 101. Cutting telescopic rod; 103. Extrusion guide plate; 104. Cutting blade; 105. Arc panel; 106. Deformation extrusion plate; 107. Elastic insulating plate; 108. Piezoelectric ceramic plate. DETAILED DESCRIPTION

[0049] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation methods.

[0050] See also Figure 1 , Example 1

[0051] The preparation of a pressure-sensitive adhesive provided in this embodiment comprises the following steps:

[0052] 25 parts of ethyl acrylate, 22 parts of isooctyl methacrylate, 7 parts of methacrylic acid and 0.25 parts of hydroxyethyl methacrylate were dissolved in 55 parts of butyl acetate and stirred evenly to obtain a mixed solution; the mixed solution was heated to 85°C, 0.05 parts of methyl ethyl ketone peroxide and 8 parts of methyl acrylate were added, and the mixture was reacted for 3 hours, then 0.2 parts of polyether modified silicone was added, stirred and mixed for 10 minutes, and the temperature was lowered to 35°C to obtain a pressure-sensitive adhesive. Example 2

[0053] This embodiment provides a method for preparing a BOPP tape with an oxidatively discolored fracture, the steps of which are as follows:

[0054] Preparation of S1 photosensitive color-changing emulsion: acrylic emulsion and spiropyran dye are mixed in a mass ratio of 80:2.5;

[0055] S2: The photosensitive color-changing emulsion and the pressure-sensitive adhesive obtained in Example 1 are sequentially coated on the BOPP biaxially oriented polypropylene film to form a 10 μm thick color-changing layer and a 10 μm thick adhesive layer, respectively, to obtain the adhesive tape and then roll it up.

[0056] The inner layer of the BOPP biaxially oriented polypropylene film in this embodiment and the area between the color-changing layer and the adhesive layer are treated to be opaque so that the color changes only at the fracture. Example 3

[0057] This embodiment provides a method for preparing a BOPP tape with an oxidatively discolored fracture, the steps of which are as follows:

[0058] S1 Preparation of chitosan methacrylate: 13 parts of chitosan were dissolved in an acetic acid aqueous solution, heated to 85°C, 108 parts of methacrylate, 1 part of vinyl triisopropoxy silicon, and 0.5 parts of potassium persulfate were added in sequence, and then heated to 88°C to react to obtain the chitosan methacrylate;

[0059] Preparation of S2 photochromic emulsion: acrylic emulsion, spiropyran dye and chitosan methacrylate are mixed in a mass ratio of 80:2.5:20;

[0060] S3: The photosensitive color-changing emulsion and the pressure-sensitive adhesive obtained in Example 1 are sequentially coated on the BOPP biaxially oriented polypropylene film to form a 10 μm thick color-changing layer and a 10 μm thick adhesive layer, respectively, to obtain the adhesive tape and roll it up.

[0061] The inner layer of the BOPP biaxially oriented polypropylene film in this embodiment and the area between the color-changing layer and the adhesive layer are treated to be opaque so that the color changes only at the fracture.

[0062] The adhesive tape of this embodiment has significantly better tensile properties than the color-changing layer in the adhesive tape of Example 2. When the adhesive tape of this embodiment and the adhesive tape of Example 3 are subjected to a tensile force of 100N, the color change of the fracture of this embodiment remains consistent with that when no tensile force is applied, while the color change of the fracture of the adhesive tape of Example 2 is intermittent. It can be seen that the addition of chitosan methacrylate in this embodiment has a more stable color change performance. Example 4

[0063] This embodiment provides a method for preparing a BOPP tape with an oxidatively discolored fracture, the steps of which are as follows:

[0064] S1 Preparation of chitosan methacrylate: 10 parts of chitosan were dissolved in an acetic acid aqueous solution, heated to 82°C, 110 parts of methacrylate, 3 parts of vinyl triisopropoxy silicon, and 0.6 parts of potassium persulfate were added in sequence, and then heated to 92°C to react to obtain the chitosan methacrylate;

[0065] Preparation of S2 photochromic emulsion: acrylic emulsion, spiropyran dye and chitosan methacrylate are mixed in a mass ratio of 90:3:10;

[0066] S3: The photosensitive color-changing emulsion and the pressure-sensitive adhesive obtained in Example 1 are sequentially coated on the BOPP biaxially oriented polypropylene film to form a 10 μm thick color-changing layer and a 10 μm thick adhesive layer, respectively, to obtain the adhesive tape and then roll it up.

[0067] In this embodiment, the inner layer of the BOPP biaxially oriented polypropylene film and the area between the color-changing layer and the adhesive layer are treated to be opaque so as to achieve color change only at the fracture. Specifically, a light-shielding layer is provided. Example 5

[0068] This embodiment provides a method for preparing a BOPP tape with an oxidatively discolored fracture, the steps of which are as follows:

[0069] S1 Preparation of chitosan methacrylate: 15 parts of chitosan were dissolved in an acetic acid aqueous solution and heated to 80°C, and 100 parts of methacrylate, 2 parts of vinyl triisopropoxy silicon, and 0.4 parts of potassium persulfate were added in sequence, and then heated to 85°C to react to obtain the chitosan methacrylate;

[0070] Preparation of S2 photochromic emulsion: acrylic emulsion, spiropyran dye and chitosan methacrylate were mixed in a mass ratio of 90:3:12;

[0071] S3: The photosensitive color-changing emulsion and the pressure-sensitive adhesive obtained in Example 1 are sequentially coated on the BOPP biaxially oriented polypropylene film to form a 10 μm thick color-changing layer and a 10 μm thick adhesive layer, respectively, to obtain the adhesive tape and then roll it up.

[0072] In this embodiment, the inner layer of the BOPP biaxially oriented polypropylene film and the area between the color-changing layer and the adhesive layer are treated to be opaque so as to achieve color change only at the fracture. Specifically, a light-shielding layer is provided.

[0073] It should be noted that the pressure-sensitive adhesive of the embodiment of the present invention can also be prepared using other methods. As long as the pressure-sensitive adhesive does not affect the color-changing function, it can be used in the adhesive tape of the embodiment of the present invention.

[0074] In addition, see Figures 2 to 11In the above embodiment, the winding process in step S3 is performed by an automatic winding mechanism, which includes an empty roller track 7, a vertical lifting track 8 and a full roller track 9 which are arranged in parallel and at intervals for guiding the core shaft 61 at both ends of the winding roller 6; the two ends of the core shaft 61 extend outward from the track surface respectively; the empty roller track 7 is inclined downward, and a plurality of first stop blocks 71 for movable stopping the core shaft 61 are arranged on the support surface along the length direction of the empty roller track 7; the lower end of the vertical lifting track 8 is connected to one side of the lower end of the empty roller track 7; the vertical lifting track A vertical push telescopic rod 81 is arranged outside the track surface below 8; a first arc-shaped supporting plate 82 is arranged on the upper end of the vertical push telescopic rod 81; the first arc-shaped supporting plate 82 lifts the core shaft 61 from the track surface outside the vertical lifting track 8 to lift the empty winding roller 6 to the top of the vertical lifting track 8; a first rotation limiting arc-shaped portion 83 is arranged on the circumference of the core shaft 61 at the top of the vertical lifting track 8; a driving gear 84 is arranged outside the track surface at the top of the vertical lifting track 8; a gear ring is arranged on the outer circumferential surface of the core shaft 61 corresponding to the driving gear 84; the winding roller 6 is pushed vertically by the vertical push telescopic rod 81 When it reaches the top of the vertical lifting track 8, the gear ring just meshes with the driving gear 84; one end of the full roller track 9 is connected and communicated with the other side of the vertical lifting track 8, and the connection point is the position below the top of the vertical lifting track 8; the full roller track 9 is first tilted upward from one end of the connection with the vertical lifting track 8 to the other end to form an inclined rising track 91, and then tilted downward to form an inclined descending track 92; the inclined rising track 91 and the inclined descending track 92 are smoothly connected and communicated; corresponding to the direction of the inclined rising track 91, an oblique push telescopic rod 93 is provided outside the track surface on one side of the vertical lifting track 8; A second arc-shaped support plate 94 is arranged at the outer end of the telescopic rod 93; the second arc-shaped support plate 94 pushes the core shaft 61 from the track surface of the vertical lifting track 8 and the inclined lifting track 91 so that the full roll after winding is completed enters the inclined lifting track 91; the front and rear positions of the first arc-shaped support plate 82 and the second arc-shaped support plate 94 are staggered; the position of the third rotation limiting arc portion 95 is lower than the top position of the vertical lifting track 8 so that the empty winding roller 6 located at the top of the vertical lifting track 8 can support the tape between the full winding roller 6 located at the third rotation limiting arc portion 95 and the tape feeding direction.

[0075] Furthermore, an extrusion guide cutting mechanism is also provided above the vertical lifting track 8; the extrusion guide cutting mechanism includes a cutting telescopic rod 101, an extrusion guide plate 103 vertically fixed to the lower end of the cutting telescopic rod 101, and a cutting blade 104; the extrusion guide plate 103 includes an arc panel 105 set corresponding to the arc of the diameter of the rolled tape roll and a deformed extrusion plate 106 connected to the extrusion guide plate 103 near the end of the inclined descending track 92; the cutting blade 104 is connected to the deformed extrusion plate 1 06 is close to one end of the descending track 92; the deformable extrusion plate 106 includes a horizontally arranged and centrally located elastic insulating plate 107 and piezoelectric ceramic plates 108 attached to the upper and lower surfaces of the elastic insulating plate 107; under the control of the electric field, the upper piezoelectric ceramic plate 108 is extended and the lower piezoelectric ceramic plate 108 is shortened, which can drive the piezoelectric ceramic plate 108 to bend into an arc surface attached to the outer circumference of the tape roll; when the piezoelectric ceramic plate 108 is bent and attached to the tape roll, it drives the cutting blade 104 to deflect downward and cut the tape.

[0076] Furthermore, a second rotation limiting arc portion 85 is provided at the bottom end of the vertical lifting track 8 corresponding to the circumference of the core shaft 61 .

[0077] Furthermore, the end of the inclined descending track 92 is open, and the track support surface extends toward the end, and a third rotation limiting arc surface portion 95 and a second stop block 96 are provided at the extended portion.

[0078] Furthermore, a plurality of through holes 72 are provided on the support surface of the empty roller track 7 corresponding to the first stop blocks 71 for the first stop blocks 71 to pass through; the first stop blocks 71 are independently driven to move by the stop telescopic rods 73 .

[0079] The winding method of the automatic winding mechanism comprises the following steps:

[0080] ① The stop telescopic rod 73 at the bottom drives the corresponding first stop block 71 to move downward, so that the upper end surface of the first stop block 71 is flush with the support surface of the empty roller track 7, so that the empty winding roller 6 stopped by the first stop block 71 rolls downward to the second rotation limit arc surface 85 of the vertical lifting track 8; then the stop telescopic rod 73 drives the bottom first stop block 71 to be lifted to the stop position extending into the empty roller track 7; then the stop telescopic rod 73 adjacent to the stop telescopic rod 73 repeats the action of the stop telescopic rod 73 in turn, so that all the empty rollers are sequentially lowered by one stop position;

[0081] ② Push the telescopic rod 81 vertically to lift the empty winding roller 6 to the top of the vertical lifting track 8, so that the ring gear on the core shaft 61 is meshed with the driving gear 84, and the driving gear 84 drives the winding roller 6 to rotate and rewind;

[0082] ③ When the winding is about to be completed, the vertical push telescopic rod 81 drives the winding roller 6 to descend to the corresponding entrance position of the inclined ascending track 91. While descending to this position, the oblique push telescopic rod 93 just contacts the core shaft 61 to push the winding roller 6 to enter and move along the inclined ascending track 91 to the intersection with the inclined descending track 92 to stop. At this time, the vertical push telescopic rod 81 continues to move down to the bottom end of the vertical lifting track 8; the winding roller 6 rolls along the inclined descending track 92 to the third rotation limit arc portion 95 under the action of gravity and inertia; in this process, the moving distance of the winding roller 6 on the full roller track 9 automatically compensates for the continuous feeding amount of the tape;

[0083] ④ While the oblique telescopic rod 93 pushes the winding roller 6, the vertical telescopic rod 81 that has been lowered to the initial position lifts the second empty winding roller 6 that enters the second rotation limit arc panel 85 to the top of the vertical lifting track 8; before the second winding roller 6 is lifted to the top of the vertical lifting track 8, the first winding roller 6 has not yet rolled to the third rotation limit arc surface 95;

[0084] ⑤ While step ④ is being performed, the cutting telescopic rod 101 drives the extrusion guide plate 103 to move downward, and first the arc panel 105 contacts the adhesive tape supported on the empty winding roller 6 located at the top of the vertical lifting track 8 at this time, and extrudes and guides the adhesive tape along the surface of the winding roller 6, so that the contact between the adhesive tape and the surface of the winding roller 6 is changed from line contact to surface contact; at the same time, the deformed extrusion plate 106 is controlled to bend downward by an external electric field, so as to further increase the surface contact area between the adhesive tape and the surface of the winding roller 6. At the same time, the deformed extrusion plate 106 drives the cutting blade 104 to deflect downward during the outward bending process to cut the adhesive tape; at this time, the adhesive tape of the fully rolled winding roller 6 located at the third rotation limiting arc portion 95 is cut, and the adhesive tape on one side of the cut is completely rolled up under the inertial rotation of the fully rolled winding roller 6; the adhesive tape on the other side of the cut is squeezed by the extrusion guide plate 103 and adheres to the winding roller 6 located at the top of the vertical lifting track 8 at this time over a large area for a new round of winding.

[0085] See also Figures 12 to 14 In the above embodiment, the coating process of S3 is carried out by a coating device, which includes a glue storage chamber 2 suspended and fixed above the film 1; a bowl-shaped polarizer 3 with a horizontal bottom is arranged outside the glue storage chamber 2; along the forward direction of the film 1, a plurality of power push rods 31 are horizontally connected between the front and rear inner walls of the polarizer 3 and the glue storage chamber 2; the power push rods 31 support the polarizer 3 to be suspended in the air and can drive the polarizer 3 to repeatedly translate back and forth at high speed; a glue outlet seam 32 is provided at the center of the bottom of the polarizer 3 along the width direction of the film 1; detachable glue coating sheets 33 are respectively attached to the bottom of the polarizer 3 on both sides of the front and rear of the glue outlet seam 21; the glue storage chamber 2 and the polarizer 3 enclose a glue extrusion chamber 34; a plurality of through holes are provided on the side wall of the glue storage chamber 2 to connect the glue extrusion chamber 34 and the glue storage chamber 2.

[0086] Furthermore, wind deflectors 4 are provided on the front and rear sides of the polarizer 3 respectively; the upper end of the wind deflector 4 is hinged on a fixed beam 5; the lower end extends to the top of the film 1 and close to the film 1; the wind deflector 4 and the front and rear walls of the polarizer 3 respectively enclose a suction chamber 41; along the width direction of the film 1, the left and right sides of the suction chamber 41 are respectively abutted against a side wind deflector 42 to shield the left and right sides of the suction chamber 41; an elastic expansion sheet 43 is connected to the upper part of the suction chamber 41 between the upper end of the polarizer 3 and the wind deflector 4 to shield the upper part of the suction chamber 41; a telescopic driving mechanism 44 is connected to the outer wall of the lower part of the wind deflector 4; the other end of the telescopic driving mechanism 44 is fixed on a vertical fixed plate 45; the vertical fixed plate 45 is fixedly connected to the fixed beam 5; the telescopic driving mechanism 44 controls the size of the suction port 47 formed by the lower part of the wind deflector 4 and the lower part of the polarizer 3; a suction pipe 46 connected to the suction chamber 41 is fixed on the elastic expansion sheet 43.

[0087] Furthermore, the glue storage chamber 2 is wide at the top and narrow at the bottom, and the front and rear side walls of the polarizer 3 are arranged vertically, so that the enclosed glue extrusion chamber 34 is narrow at the top and wide at the bottom. The bottoms of the front and rear side walls of the polarizer 3 are rounded; the lower end of the wind deflector 4 is bent toward the side of the polarizer 3; a glue supply hose 21 is inserted from the top of the glue storage chamber 2; the lower end of the wind deflector 4 is deflected toward the side of the polarizer 3 so that the air suction chamber 41 is larger at the top and smaller at the bottom.

[0088] Furthermore, the power push rod 31 includes a hollow cylindrical barrel 311, a piston 312 slidably sleeved in the barrel 311, and a rod body 313 with one end connected to the piston 312 and the other end extending out of the barrel 311; the piston 312 and the barrel 311 enclose a liquid cavity 314; an electrode pair 315 is arranged in the liquid cavity 314; the liquid cavity 314 is filled with water; an external circuit applies an electric field to the electrode pair 315 to generate a liquid-electric effect to impact the piston 312 to push the rod body 313 outward.

[0089] Furthermore, the telescopic driving mechanism 44 includes a first rod 441 and a second rod 442 which are arranged opposite to each other, and a linear sleeve 443 which is slidably sleeved on the outside of the first rod 441 and the second rod 442 at the same time; a partition plate 444 is fixed in the middle part of the linear sleeve 443; an arc-shaped piezoelectric deformation plate 445 is fixed at the left and right ends of the partition plate 444; the upper and lower ends of the piezoelectric deformation plate 445 are fixedly connected to the partition plate 444 respectively; the piezoelectric deformation plate 445 includes a middle elastic insulating sheet 447 and a piezoelectric ceramic sheet 448 attached to both sides of the middle elastic insulating sheet 447; under the action of an external electric field, one of the two piezoelectric ceramic sheets 448 is extended and the other is shortened, so that the middle part of the piezoelectric deformation plate 445 bulges outward, thereby pushing the first rod 441 and the second rod 442 to extend.

[0090] The coating method of the coating device comprises the following steps:

[0091] ① The film 1 passes forward from under the polarizer 3, with a small gap between it and the polarizer 3; at the same time, an electric field is applied alternately to the electrode pairs 315 in the power push rods 31 on the left and right sides to generate a hydroelectric effect in the water in the liquid chamber 314, generating an impact force to push the piston 312 and the rod body 313 outward; thereby, the polarizer 3 is repeatedly moved back and forth quickly and in a small amplitude along the forward direction of the film 1;

[0092] ② When the rear power push rod 31 pushes, the polarizer 3 moves forward, squeezing the front glue extrusion cavity 34, and the glue liquid in the side glue extrusion cavity 34 is squeezed out from the glue outlet slit 32 onto the film 1. At the same time, the polarizer 3 moves forward at the same time, so the glue coating sheet 33 at its lower end smears the glue liquid forward; at the same time, the front air suction port 47 is reduced in size and the wind speed is increased during the forward movement of the polarizer 3, and the rear air suction port 47 is increased and the wind speed is reduced, so that the film 1 in front of the glue outlet slit 32 is more tightly attached to the glue coating sheet 33, and the rear film 1 is loosely attached to the glue coating sheet 33, thereby matching the moving direction of the polarizer 3 at this time, and adsorbing the glue liquid to flow in the moving direction of the polarizer 3, which is convenient for the directional expansion of the glue liquid in the glue coating action;

[0093] ③ When the front power push rod 31 pushes, the polarizer 3 moves forward and backward, squeezing the glue extrusion cavity 34 at the rear, and the glue liquid in the glue extrusion cavity 34 is squeezed out from the glue outlet slit 32 onto the film 1. At the same time, the polarizer 3 moves backward at the same time, so the glue coating sheet 33 at its lower end smears the glue liquid backward; at the same time, the air suction port 47 at the rear is reduced in size and the wind speed is increased during the backward movement of the polarizer 3, and the air suction port 47 at the front is increased and the wind speed is reduced, so that the film 1 behind the glue outlet slit 32 is more tightly attached to the glue coating sheet 33, and the front film 1 is loosely attached to the glue coating sheet 33, thereby matching the moving direction of the polarizer 3 at this time, and adsorbing the glue liquid to flow in the moving direction of the polarizer 3, which is convenient for the directional expansion of the glue liquid in the glue coating action;

[0094] ④ If it is found during the glue coating process that the flow expansibility of the glue on the film 1 deviates greatly from the set requirements, the piezoelectric ceramic piece 448 can be controlled by the circuit to extend or shorten so that the protruding distance of the middle part of the piezoelectric deformation plate 445 becomes longer or shorter, thereby synchronously supplementing and adjusting the size change of the suction port 47 each time the size of the suction port 47 changes.

[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a BOPP tape with oxidatively discolored fracture, characterized in that: It includes the following steps: S1 Preparation of photochromic emulsion: acrylic emulsion and organic photochromic material are mixed to prepare photochromic emulsion; S2 Preparation of pressure-sensitive adhesive; S3: coating a photosensitive color-changing emulsion and a pressure-sensitive adhesive on a BOPP biaxially oriented polypropylene film in sequence to form a color-changing layer and an adhesive layer respectively to obtain the adhesive tape, and then winding the tape; The organic photochromic material is a spiropyran dye, and the mass ratio of the acrylic emulsion to the organic photochromic material is 80-90:2-3; Chitosan methacrylate is also added to the organic photochromic material, and the mass ratio of chitosan methacrylate to acrylic emulsion is 10-20:80-90; The preparation of chitosan methacrylate comprises the following steps: dissolving 10-15 parts of chitosan in an acetic acid aqueous solution, heating to 80-85° C., sequentially adding 100-110 parts of methacrylate, 1-3 parts of vinyl triisopropoxy silicon, and 0.4-0.6 parts of potassium persulfate, and then heating to 85-92° C. to react and obtain the chitosan methacrylate; The inner layer of the BOPP biaxially oriented polypropylene film and the area between the color-changing layer and the adhesive layer are treated to be opaque so as to achieve color change only at the fracture.

2. The method for preparing the BOPP tape with oxidatively discolored fracture surface as claimed in claim 1, characterized in that: The automatic winding mechanism comprises an empty roller track (7), a vertical lifting track (8) and a full roller track (9) which are arranged in parallel and at intervals and are used to guide the core shaft (61) at both ends of the winding roller (6); the two ends of the core shaft (61) extend outward from the track surface respectively; the empty roller track (7) is inclined downward, and a plurality of first stop blocks (71) which can moveably stop the core shaft (61) are arranged at intervals on the support surface along the length direction of the empty roller track (7); the lower end of the vertical lifting track (8) is connected to one side of the lower end of the empty roller track (7); a vertical push telescopic rod (81) is arranged outside the track surface below the vertical lifting track (8); and a first arc-shaped The supporting plate (82) is provided with a first arc-shaped supporting plate (82) to lift the core shaft (61) from the outside of the track surface of the vertical lifting track (8) to lift the empty winding roller (6) to the top of the vertical lifting track (8); the top of the vertical lifting track (8) is provided with a first rotation limiting arc surface (83) on the circumference of the core shaft (61); the top of the vertical lifting track (8) is provided with a driving gear (84) outside the track surface; the core shaft (61) is provided with a gear ring on the outer circumferential surface corresponding to the driving gear (84); when the vertically pushing telescopic rod (81) pushes the winding roller (6) vertically to the top of the vertical lifting track (8), the gear ring just meshes with the driving gear (84); the full roller track (9) is provided with a first rotation limiting arc surface (83) on the circumference of the core shaft (61); the top of the vertical lifting track (8) is provided with a driving gear (84); the full roller track (9) is provided with a first rotation limiting arc surface (83) on the circumference of the core shaft (61) One end is connected to the other side of the vertical lifting track (8), and the connection point is below the top of the vertical lifting track (8); the full roller track (9) is first tilted upward from one end of the connection point with the vertical lifting track (8) to the other end to form an inclined rising track (91), and then tilted downward to form an inclined descending track (92); the inclined rising track (91) and the inclined descending track (92) are smoothly connected and connected; corresponding to the direction of the inclined rising track (91), an inclined push telescopic rod (93) is provided outside the track surface on one side of the vertical lifting track (8); a second arc-shaped support plate (94) is provided at the outer end of the inclined push telescopic rod (93); the second arc-shaped support plate (94) is connected from the vertical lifting track (8) and the inclined rising track (91). The track surface of the track (91) pushes the core shaft (61) outward to allow the fully wound roll to enter the inclined track (91); the first arc-shaped support plate (82) and the second arc-shaped support plate (94) are staggered in front and back positions; the end of the inclined descending track (92) is open, and the track support surface extends toward the end, and the extended portion is provided with a third rotation limiting arc portion (95) and a second stop block (96); the position of the third rotation limiting arc portion (95) is lower than the top position of the vertical lifting track (8), so that the empty winding roller (6) located at the top of the vertical lifting track (8) can support the tape between the fully wound winding roller (6) located at the third rotation limiting arc portion (95) and the tape feeding direction.

3. The method for preparing the BOPP tape with oxidatively discolored fracture surface as claimed in claim 2, characterized in that: An extrusion guide cutting mechanism is also arranged directly above the vertical lifting track (8); the extrusion guide cutting mechanism comprises a cutting telescopic rod (101), an extrusion guide plate (103) vertically fixed to the lower end of the cutting telescopic rod (101), and a cutting blade (104); the extrusion guide plate (103) comprises an arc plate (105) arranged corresponding to the arc of the diameter of the rolled tape roll and a deformable extrusion plate (106) connected to the extrusion guide plate (103) near one end of the inclined descending track (92); the cutting blade (104) is connected to the deformable extrusion plate (105) 06) is close to one end of the descending track (92); the deformable extrusion plate (106) includes an elastic insulating plate (107) arranged horizontally and located in the middle, and a piezoelectric ceramic plate (108) attached to the upper and lower surfaces of the elastic insulating plate (107); under the control of the electric field, the upper piezoelectric ceramic plate (108) is extended and the lower piezoelectric ceramic plate (108) is shortened, so that the piezoelectric ceramic plate (108) can be driven to bend into an arc surface to be attached to the outer circumference of the tape roll; when the piezoelectric ceramic plate (108) is bent to be attached to the tape roll, the cutting blade (104) is driven to deflect downward to cut the tape.

4. The method for preparing the BOPP tape with oxidatively discolored fracture surface as claimed in claim 3, characterized in that: A second rotation limiting arc portion (85) is provided at the bottom end of the vertical lifting track (8) corresponding to the circumference of the core shaft (61).

5. The method for preparing the BOPP tape with oxidatively discolored fracture surface as claimed in claim 4, characterized in that: A plurality of through holes (72) are provided on the support surface of the empty roller track (7) corresponding to the first stop block (71) for the first stop block (71) to pass through; the first stop block (71) is independently driven to move by the stop telescopic rod (73).

6. The method for preparing the BOPP tape with oxidatively discolored fracture surface as claimed in claim 5, characterized in that: The winding method of the automatic winding mechanism comprises the following steps: ① The stop telescopic rod (73) located at the bottom drives the corresponding first stop block (71) to move downward, so that the upper end surface of the first stop block (71) is flush with the support surface of the empty roller track (7), so that the empty winding roller (6) stopped by the first stop block (71) rolls downward to the second rotation limit arc surface (85) of the vertical lifting track (8); then the stop telescopic rod (73) drives the bottom first stop block (71) to be lifted to the stop position extending into the empty roller track (7); then the stop telescopic rod (73) adjacent to the stop telescopic rod (73) repeats the action of the stop telescopic rod (73) in turn, so that all the empty rollers are sequentially lowered by one stop position; ② Push the telescopic rod (81) vertically to lift the empty winding roller (6) to the top of the vertical lifting track (8), so that the gear ring on the mandrel (61) meshes with the driving gear (84), and the driving gear (84) drives the winding roller (6) to rotate and rewind; ③ When the winding is about to be completed, the vertical push telescopic rod (81) drives the winding roller (6) to descend to the corresponding entrance position of the inclined ascending track (91). While descending to this position, the inclined push telescopic rod (93) just contacts the core shaft (61) to push the winding roller (6) into and move along the inclined ascending track (91) to the intersection with the inclined descending track (92) and stop. At this time, the vertical push telescopic rod (81) continues to move down to the bottom end of the vertical lifting track (8); the winding roller (6) rolls along the inclined descending track (92) to the third rotation limit arc portion (95) under the action of gravity and inertia; in this process, the moving distance of the winding roller (6) on the full roller track (9) automatically compensates for the continuous feeding amount of the tape; ④ While the oblique telescopic rod (93) pushes the winding roller (6), the vertical telescopic rod (81) that has been lowered to the initial position lifts the second empty winding roller (6) that enters the second rotation limit arc portion (85) to the top of the vertical lifting track (8); before the second winding roller (6) is lifted to the top of the vertical lifting track (8), the first winding roller (6) has not yet rolled to the third rotation limit arc portion (95); ⑤ While step ④ is being performed, the telescopic rod (101) is cut off to drive the extrusion guide plate (103) to move downward, and first the arc panel (105) contacts the adhesive tape supported on the empty winding roller (6) located at the top of the vertical lifting track (8), and extrudes and guides the adhesive tape along the surface of the winding roller (6), so that the contact between the adhesive tape and the surface of the winding roller (6) is changed from line contact to surface contact; at the same time, the deformed extrusion plate (106) is controlled to bend downward by an external electric field, so as to further increase the surface contact between the adhesive tape and the surface of the winding roller (6). At the same time, the deformed extrusion plate (106) drives the cutting blade (104) to deflect downward during the process of bending outward, thereby cutting the tape; at this time, the tape on the fully rolled reel (6) located at the third rotation limit arc portion (95) is cut, and the tape on one side of the cut-off is completely rolled up under the inertial rotation of the fully rolled reel (6); the tape on the other side of the cut-off is squeezed by the extrusion guide plate (103) and adheres to a large area on the reel (6) located at the top of the vertical lifting track (8) for a new round of reeling.

7. A BOPP tape with oxidative color-changing fracture surface obtained by the preparation method according to any one of claims 1 to 6.

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