881 results about "Kraft paper" patented technology

The invention provides a kraft paper wet water full-automatic corner and edge box sealing machine which comprises a rack, a conveying belt assembly, a corner and edge unit and a shaping assembly, through four specially-designed tape pasting mechanisms, automatic water dipping, accurate length determining, automatic cutting and pasting of water-based adhesive tape are achieved, and the production efficiency is improved. The automatic edge banding device is simple in structure and matched with the shaping mechanism to ensure that the adhesive tape is firmly attached to the four linear edges of the carton, efficient and synchronous four-corner automatic edge banding is achieved, in addition, the device can adapt to cartons of different sizes through the design of the height adjusting mechanism and the horizontal adjusting mechanism, and universality and flexibility are improved. According to the four-corner edge sealing machine, the problems of application of environment-friendly materials and packaging of four corners of a carton in the prior art are solved, and an efficient, reliable and low-cost carton four-corner edge sealing scheme is provided for the industry through unique design and technical improvement of the four-corner edge sealing machine.

The present invention discloses a tensile and wear-resistant washed kraft paper and its preparation process, which relates to the technical field of kraft paper. The process includes the following steps: Step 1: Add color paste, waterborne acrylic resin, preservative, reinforcing agent, softening agent, curing agent, and waterproofing agent into a solvent in sequence and stir evenly to obtain a sizing slurry; Step 2: Coat the sizing slurry on the base paper, and successively perform extrusion, ultraviolet light irradiation, first drying, ironing, and second drying to obtain the tensile and wear-resistant washed kraft paper. In this application, by preparing specific reinforcing agent and waterproofing agent and introducing them into the sizing slurry for sizing, the interfacial action between the sizing slurry and the base paper is effectively improved, thereby improving the tensile and wear resistance of the washed kraft paper while enhancing the flame retardant performance; it can achieve the purpose of replacing plastic, leather, and cloth with paper.

The invention discloses a preparation method of a CoCrNi medium-entropy alloy and Q235B steel explosive welding composite board, which comprises the following steps of: annealing a CoCrNi medium-entropy alloy board, sequentially laying sandy soil, an anvil, a Q235B hot-rolled steel plate, a support column, a medium-entropy alloy board, kraft paper and explosive from bottom to top on an explosion field, and performing explosive welding to obtain the CoCrNi medium-entropy alloy and Q235B steel explosive welding composite board. The detonation velocity of the explosive ranges from 2500 m / s to 3000 m / s, and the brisance of the explosive ranges from 18 mm to 22 mm. According to the method, metallurgical bonding of the CoCrNi medium entropy alloy and the Q235B steel plate is achieved, the interface bonding rate of the obtained composite plate is larger than 99.2%, the yield strength is larger than 420 MPa, the tensile strength is larger than 500 MPa, the percentage elongation after fracture is larger than 35%, and the interface shear strength is larger than 200 MPa. The method is simple in process and suitable for industrial production.

The invention relates to the technical field of packaging bags, and discloses a moisture-proof medical packaging bag material and a preparation method thereof. The moisture-proof medical packaging bag material comprises a paper layer and a plastic layer, the paper layer comprises modified kraft paper, and the plastic layer comprises the following raw materials in parts by weight: 70-100 parts of polybutylene terephthalate adipate, 30-50 parts of polypropylene carbonate, 5-7 parts of modified mica and 1.5-3 parts of cellulose acetate oleate. The moisture-proof medical packaging bag material prepared by the invention has good water resistance and mechanical properties, also has good degradability, and has a good application prospect.

The present invention relates to a multilayer sheet liner for a food or beverage packaging material, the multilayer sheet liner comprising: a first ply comprising at least 70% by weight of unbleached kraft pulp and less than 30% by weight of neutral sulfite semi-chemical (NSSC) pulp, based on dry weight, and a second ply comprising at least 70% by weight of unbleached kraft pulp and less than 30% by weight of neutral sulfite semi-chemical (NSSC) pulp, based on dry weight, wherein the second ply comprises at least 50% by weight of NSSC pulp and less than 50% by weight of unbleached kraft pulp based on dry weight, and wherein the NSSC pulp in the second ply is a washed NSSC pulp having an ash content of less than 1.8% by weight as determined according to Standard ISO 1762: 2019. The invention relates to a method for manufacturing the multilayer sheet liner.

The invention relates to the technical field of spunbond non-woven fabric manufacturing, in particular to a low-cost recyclable spunbond non-woven fabric manufacturing method capable of replacing traditional kraft paper, and the method comprises the steps of raw material preparation, melt extrusion, spinning web forming, hot-press shaping, cooling and trimming, post-processing, coiling and forming and the like. Raw materials comprise polypropylene particles, degradable master batches and recycled spunbond non-woven fabric fragments, the recycled fragments are subjected to surface modification treatment, and the degradable master batches contain polylactic acid, a starch-based degradation agent and other components. The non-woven fabric is quantified to 80-120 g / m < 2 > by optimizing processes such as a barrier type screw, infrared preheating and laser trimming and cooperating with water-repellent and antistatic post-treatment, the mechanical properties such as tensile strength, tearing strength and folding resistance are superior to those of traditional kraft paper, the non-woven fabric can be recycled for at least three times, and the degradation period is controllable; the method realizes closed-loop utilization of raw materials, reduces cost and energy consumption, expands application in the fields of packaging, agriculture and the like, and has remarkable economic and environmental benefits.

1. The name of the product of this design: Kraft paper toy (whale shark). 2. Purpose of this design product: for toys. 3. The design key point of this appearance design product lies in the shape. 4. The picture or photo that best illustrates the design points: three-dimensional picture.

The invention provides a printing method and a printing system for simulating kraft paper to print a digital manuscript and a computer readable storage medium. The printing method comprises the following steps: S1, determining color feature data of a pattern of a digital draft printed on real kraft paper; s2, generating a target characteristic file based on the color characteristic data; s3, simulated kraft paper color and simulated kraft paper texture are added; s4, determining CMYK four-color values for simulating the paper color of the kraft paper; and S5, based on the target characteristic file, the CMYK four-color values of the paper color of the simulated kraft paper and the texture of the simulated kraft paper, printing the digital draft to obtain the simulated kraft paper printing digital draft. According to the printing method, a standard basis is provided for printing of kraft paper, the printing effect can be guaranteed, and the complex printing process and cost can be saved.

The invention relates to a method for manufacturing SCK paper having a basis weight in the range of 50 to 100 g / m2, wherein an optimal combination of nonrecycled BCP, BCTMP and recycled pulp obtained from release liner supercalendered Kraft paper is used to adjust the properties of the fiber furnish. While the use of BCTMP enables a product having a higher bulk, the recycled pulp component, which has high compatibility with the paper manufacturing process, enables to balance the manufacturing process and reduce the dimensional changes and shrinkage of the formed SCK paper. The combined presence of the BCTMP and the recycled pulp component in the fiber furnish improves the water removal from the fibers during the SCK paper manufacturing, while the presence of non-recycled BCP produced from softwood improves the formation and runnability of the paper web on the paper machine. This enables to produce SCK paper with improved sustainability, wherein the density may be controlled by means of the fiber furnish, without downgauging and without adverse effects to other paper properties, which would prevent the use of the SCK paper as substrate layer in a release liner.

The invention relates to the related technical field of circuit board manufacturing, in particular to a circuit board multilayer uniform pressing buffer device which comprises a fixing frame, a pressing assembly is arranged on the upper surface of a top plate, a mold assembly is arranged on the inner side surface of the pressing assembly, and a buffer assembly is arranged on the outer side surface of the mold assembly. And a typesetting assembly is arranged on the upper surface of the buffer assembly. According to the buffer device for multilayer uniform pressing of the circuit board, through the arrangement of the buffer assembly and the typesetting assembly, the circuit board needs to be arranged, new kraft paper is used for preventing skid, a high-expansion steel plate is used for buffering pressure, a prepreg is heated and melted to bond and fix the circuit board, during pressing, a pressing plate drives an upper mold, and the pressure passes through a buffer pad, a sliding plate and a connecting block to compress a buffer spring; the damper converts and consumes energy, and the high-expansion steel plate, the prepreg and the new kraft paper act together to uniformly distribute pressure, so that multi-layer uniform lamination is realized, the plate thickness balance and the adhesive uniformity are ensured, and the damage to the circuit board is reduced.

A packaging material consisting of an unbleached kraft paper as a base paper, —the kraft paper has at least 90% primary cellulose and a grammage of between 65 g / m2 and 170 g / m2; —the primary cellulose, containing at least 80% cellulose with a length-weighted mean fiber length of between 2.0 mm and 2.9 mm, and less than 5% fillers, —the primary cellulose is cellulose beaten with high consistency, —the packaging material has a strain ratio break of >1.1, a tear length in the machine direction of >10 km, and a tear index in the cross direction of >16.0 mN·m2 / g. The invention also relates to a method for manufacturing the packaging material, to a sleeve produced from the packaging material, and to a use of the packaging material.

The invention discloses a laser die-cutting machine with online burr detection and ultrasonic dust removal functions. The device sequentially comprises an unwinding assembly, a flattening roller assembly, a tape connecting platform assembly, a tension detection assembly, a tension swing roller assembly, a reinforcing rib mechanism, a die-cutting front and back CCD defect detection assembly, a die-cutting front advancing deviation correction assembly, a die-cutting front advancing deviation correction detection assembly, a laser length measurement assembly, a laser assembly, a tab air knife dust removal assembly and an A face CCD defect detection assembly from unwinding to winding. The device comprises a main driving assembly, a tab CCD size detection assembly, a before-slitting advancing deviation correction assembly, a before-slitting advancing deviation correction detection assembly, a slitting assembly, a B-face CCD flaw detection assembly, a brush dust removal assembly, an ultrasonic edge washing and dust removal assembly, a burr detection assembly, an ultrasonic face washing and dust removal assembly, an iron removal assembly, a rolling tension detection assembly, a defective labeling assembly and a rolling assembly. A rolling pressing wheel assembly, a kraft paper roll assembly and a rolling pushing assembly. According to the invention, online burr detection and efficient dust removal can be realized.

In a release paper consisting of a backing paper layer coated on at least one side with PVOH and a silicone coating on at least one side, in which the backing paper layer coated on at least one side with PVOH consists of bleached kraft paper, containing at least up to 30 wt. % softwood and hardwood with a total freeness between 30 °SR and 42 °SR, preferably between 33 °SR and 38 °SR, and processing aids, and also a release layer which is applied at least on one side to the PVOH-coated side of the backing paper layer and consists of 0.5 to 5 g / m2 of a silicone, and wherein the release paper coated at least on one side with PVOH and silicone has a density between 850 and 990 kg / m3, preferably between 900 and 970 kg / m3, and a method for producing a release paper.

The invention relates to a method for manufacturing SCK paper having a basis weight in the range of 50 to 70 g / m2, wherein an optimal combination of BSKP and BCTMP is used to adjust the properties of the fiber furnish. In SCK papers with low basis weight the bulk of the formed paper web upon paper manufacturing may be controlled by means of the fiber furnish, without downgauging and without adverse effects to other paper properties, which would prevent the use of the SCK paper as substrate layer in a release liner. Thus SCK paper with exceptionally high share of BCTMP in the fiber furnish may be produced into the same thickness as was possible before for a conventional supercalendered kraft paper having a higher basis weight, while maintaining other quality characteristics of the paper sufficient for use as a substrate layer of an industrial release liner.

The present technology relates to fluff pulp having improved odor control and methods of making such fluff pulp. A fluff pulp is provided that includes bleached kraft fibers and a copper ion content of from about 0.2 ppm to about 50 ppm by weight of the bleached kraft fibers. The bleached kraft fibers include a length-weighted average fiber length of at least about 2 mm, a copper number of less than about 7, a carboxyl content of greater than about 3.5 meq / 100 grams; an ISO brightness of at least 80; and a viscosity of from about 2 cps to about 9 cps.

According to the wet kraft paper box sealing machine, an upper box sealing device and a lower box sealing device each comprise a paper frame and a paper pressing guide assembly, a wet kraft paper roll is arranged on each paper frame, and wet kraft paper is guided to a wet kraft paper humidifying and heating device through a paper feeding guide part; the wet kraft paper passes through the wet kraft paper humidifying and heating device and waits for packaging boxes at outlets of the upper box sealing device and the lower box sealing device, and a wet kraft paper pressurizing part is arranged above a paper inlet of the wet kraft paper humidifying and heating device; water inlet and outlet holes of the two wet kraft paper humidifying and heating devices are connected into a water storage tank located on the rack at the lower end of the roller shaft layer through pipelines, and paper pressing guide assemblies are arranged on the front side and the rear side of the upper box sealing device and the front side and the rear side of the lower box sealing device correspondingly and located on the rear sides of the corresponding wet kraft paper. The device has the advantages that the cover plate is pressurized through the electromagnetic driving part to further pressurize the wet kraft paper, so that the wet kraft paper works smoothly; the wet kraft paper humidifying and heating device heats and humidifies the wet kraft paper to improve viscosity and facilitate box sealing.

The invention discloses dialdehyde starch waterproof and oilproof packaging paper and a preparation method thereof, and belongs to the technical field of packaging materials. The tapioca starch waterproof and oil-proof paper comprises raw paper, the surface of the raw paper is coated with a dialdehyde starch waterproof and oil-proof layer, and the dialdehyde starch waterproof and oil-proof layer is prepared by modifying tapioca starch through an oxidizing agent. After the prepared coating is applied to the surface of kraft paper, the coating has excellent waterproof and oil-proof performance, the situation that when the coating is in contact with food with large moisture and oil content, the moisture and the oil content can soak a package, consequently, the package is damaged, and the food package is unstable can be avoided, and the coating has good barrier performance and can be widely applied to the field of food packaging. Meanwhile, the material disclosed by the invention has good biodegradability, can be naturally degraded in the environment, and is more environment-friendly.

The utility model relates to the field of foamed sponge processing and discloses foamed sponge forming equipment which comprises a forming device, a placement groove is formed in the middle of the top end of the forming device, kraft paper is placed in the placement groove, a fixing frame is fixedly installed at an opening of the top end of the forming device, and fixing grooves are symmetrically formed in the inner wall, close to the corners of the forming device, of the fixing frame. A movable plate is movably installed in the fixing frame and extends into the fixing groove, springs are installed on the two side edges of one end of the movable plate and located in the fixing groove, and a connecting pull rod is welded to the middle of one end of the movable plate and penetrates through the fixing frame; the kraft paper is fixed to the inner wall of the containing groove through cooperation of the multiple limiting pressing plates and the movable clamping plates, so that the effect of conveniently keeping the kraft paper in the containing groove to be stably placed is achieved, and the attaching degree between the kraft paper and the inner wall of the containing groove is improved; the problem that the surface of the foamed sponge is uneven after being formed due to wrinkles of kraft paper is solved.

Systems and methods are described for fiber-based, plastic-free products for storage of emulsion food products. In some embodiments, a coating is applied to the product, such as a coating comprising efficacious proportions of xylitol, citric acid, water, microfibrillated cellulose, and polyvinyl alcohol. A slurry is used to fabricate the product includes various proportions of fiber blends (e.g., combinations of bleached softwood, bleached hardwood, kraft paper, and / or virgin fiber), AKD, starch, a stearate (e.g., Magnesium or Calcium Stearate), a defoamer, and microfibrillated cellulose.

The utility model discloses 3d honeycomb packing paper and box packing paper thereof, and relates to the field of packing paper design, the 3d honeycomb packing paper comprises a plurality of paper strips, and the plurality of paper strips are arranged with the same length and the same width; a plurality of adhesive layers are arranged on the two sides of the paper strip respectively, the adhesive layers are arranged in an equidistant array mode, and the adhesive layers on the two sides of the paper strip are arranged in a staggered mode. When the multiple paper strips are stretched in the vertical direction of the side faces, the paper strips and the adhesive layers on the two sides are stretched to form a honeycomb-shaped structure. When the paper tape is stretched, the paper tape can be stretched and deformed from the adhesive layers which are arranged in a staggered mode, the paper tape can form a honeycomb-shaped structure after being completely stretched, and due to the fact that the honeycomb-shaped structure is high in stability, the paper tape can be stretched in the stretching direction and does not deform in other directions; compared with kraft paper, the paper strip is lower in preparation cost, the strength of the 3d honeycomb packaging paper can be guaranteed by setting the corresponding width of the paper strip, and the protection effect is better.

The utility model discloses a limiting drawing display gift box, relates to the technical field of packaging boxes, and aims to solve the problems that in the prior art, a conventional packaging box for tea, wine, various hardcover gifts and the like is inconvenient to draw and display and poor in use effect. The drawing box body is connected to the interior of the outer packaging box body in a sliding mode, a hidden limiting clamp used for limiting the drawing box body is arranged in the outer packaging box body, a drawing box base is arranged on one side of the drawing box body, and the peripheral size of the drawing box base is the same as that of the outer packaging box body. The outer packaging box body and the drawing box body are both made of kraft paper and supported in a paper folding mode, first card paper is arranged in the drawing box base, a first magnetic attraction block is arranged on the inner side of the first card paper, second card paper is arranged in the drawing box base, and a second magnetic attraction block is arranged on the inner side of the second card paper. And a second magnetic attraction block is arranged on the inner side of the second card paper.

A kraft paper having a pulp according to ISO 536 of between 60 g / m2 and 120 g / m2, a density of between 680 kg / m3 and 720 kg / m3, and a tensile strength index in the machine direction according to ISO 1924-3 of between 79 kNm / kg and 98 kNm / kg, the kraft paper optionally having a coating and / or an auxiliary element on at least one side. The kraft paper is made of a pulp having an average pulp fibre length of 2.2 mm to 2.7 mm with a minimum pulp content of at least 96% wt. %; a pore volume of the uncoated kraft paper is between 200 μl / g and 220 ml / g; in the thickness direction of the paper, there are regions of different porosities; and at least one region has pores with a pore diameter of less than or equal to 0.3 μm. The invention also relates to a paper sack.

The utility model relates to the technical field of kraft paper composite forming, in particular to a multi-layer kraft paper efficient composite forming device which comprises a workbench, a first fixing frame is fixedly connected to the upper end of the workbench, and a first overlapping roller, a second overlapping roller and a third overlapping roller are sequentially and rotationally connected to the interior of the first fixing frame from left to right. The other end of the spring is fixedly connected with the sliding block, heating rods are fixedly connected to the circumferential face of the first fixing shaft and the circumferential face of the second fixing shaft, and a hot pressing mechanism is installed at the upper end of the workbench and located at the right end of the pre-pressing forming assembly. Under the action of the pre-pressing forming assembly, the drying and curing speed of glue in the kraft paper can be increased, it is guaranteed that the laminated composite kraft paper has the excellent combination degree, drying is not needed in the follow-up process, the step of drying in a drying mechanism is omitted in the whole scheme, and the production efficiency is improved. Therefore, the whole scheme is simpler, more convenient, more efficient and more convenient to use.

The utility model provides lining paper for tobacco, which comprises a lining paper roll, the lining paper roll consists of an aluminum foil layer, a waterproof film layer, a kraft paper layer and a composite paper layer, the top end of the aluminum foil layer is connected with the waterproof film layer in a bonding manner, the surface of the waterproof film layer is connected with the kraft paper layer in a bonding manner, and the surface of the kraft paper layer is connected with the composite paper layer in a bonding manner. According to the lining paper roll, the waterproof film layer and the kraft paper layer are matched, so that not only is the waterproof performance of the lining paper improved, but also the structural strength of the lining paper is improved, and cigarettes in a cigarette case are effectively protected.

The utility model discloses a corner reinforcing type packaging carton which comprises a carton body and corner reinforcing angle paper arranged at the four corner angles of the left end and the right end of the carton body, the corner reinforcing angle paper is fixedly connected with the carton body through adhesives, kraft paper is further pasted on the outer wall of the corner reinforcing angle paper and used for preventing moisture and water, and the kraft paper is fixedly connected with the carton body through adhesives. The length of the corner reinforcing angle paper is equal to the height of the carton body, a novel inner supporting protection device is additionally arranged in the corner reinforcing type packaging carton, and the two portable handle pieces of the inner supporting protection device are exposed out of the front end and the rear end of the carton respectively. The inner supporting protection device can play a supporting and reinforcing role in the carton through the inner supporting plastic frame, and due to the fact that the inner supporting plastic frame is made of plastic and tightly attached to the inner wall of the carton, the situation that the carton is prone to deformation and damage due to the fact that the carton is extruded by foreign objects in the using process can be avoided.

The utility model discloses a kraft linerboard uniformity measuring device, which relates to the technical field of kraft linerboard equipment and comprises a frame body, supporting legs are fixedly connected to four corners of the bottom of the frame body, a first fixing block is arranged in the frame body, and a lifting structure is arranged at the top of the first fixing block. The bottom of the first fixed block is connected with a first movable block through a first spring, and sliding grooves are formed in the two sides of the first movable block. The roll shaft is arranged on the outer surface of the sliding rod, the outer surface of the roll shaft can move on the outer surface of kraft linerboard through the lifting structure and the driving structure, and therefore when the thickness of the kraft linerboard is not uniform, the height of the roll shaft can be changed, and the kraft linerboard can be fixed. The pen point at one end of the sliding rod can draw lines on the surface of the liquid crystal handwriting board body along with the change of the sliding rod, so that the overall thickness of kraft linerboard can be reflected through the lines, the accuracy of detection data can be conveniently improved, and the uniformity of the kraft linerboard can be better evaluated.

The invention relates to the technical field of inflatable bubble bag composite film processing, in particular to a preparation process of a paper protective inflatable bubble bag composite film and a product thereof, and the preparation process comprises the following preparation steps: S1, coating waterproof and air-isolating glue on the surface of a base material, and drying to form a waterproof and air-isolating layer to obtain a waterproof and air-isolating composite film, the waterproof and air-insulation glue is prepared by mixing polyvinyl alcohol, polyurethane modified organic silicon, water-soluble chitosan, water-soluble acrylic resin, 2-ethylhexyl acrylate, a cross-linking agent, ethanol and water; s2, the kraft paper and the waterproof and air-proof composite film are pressed at the pressing temperature of 140-150 DEG C and the pressing pressure of 12-16 MPa, so that the kraft paper and the waterproof and air-proof layer are adhered to each other, and a kraft paper composite film is obtained; s3, tearing off the base material layer; and S4, the surface of the waterproof and air insulation layer is coated with heat sealing glue, drying is conducted, and the paper protective inflatable bubble bag composite film is obtained and has good waterproof and air insulation performance.

There is provided a coated paper comprising a kraft paper substrate, a precoating layer provided on the kraft paper substrate and a water vapour barrier coating layer provided on the pre-coating layer. The grammage according to ISO 536:2019 of the coated paper is 65-155 g / m2, the pre-coating layer comprises inorganic filler and binder in a dry weight ratio of between 100:25 and 100:5 and the water vapour barrier coating layer comprises clay pigment and styrene-butadiene co-polymer (SBR) binder in a dry weight ratio between 100:30 and 100:80. The particle size distribution (%<2 pm) of said clay pigment is above 90 and the shape factor of said clay pigment is below 20, such as below 10.

The invention discloses a preparation method of a waterproof and oilproof paper-based material containing a composite coating, and belongs to the technical field of packaging papers.The preparation method comprises the following steps that S1, a sodium alginate aqueous solution is prepared, and a coating A is obtained; s2, preparing a PLA and PBAT mixed solution to obtain a coating B; s3, uniformly coating the surface of raw kraft paper with the coating A, and then performing drying and hot pressing to obtain dry raw kraft paper with a flat surface; and S4, uniformly coating the coating B on the surface of the kraft base paper coated with the coating A, and fully drying to obtain the waterproof and oilproof paper-based material containing the sodium alginate, PLA and PBAT composite coating. The water-proof and oil-proof paper-based material prepared by the invention not only remarkably improves the water-proof and oil-proof performance of paper, but also retains the biodegradable characteristic of the paper, and has a wide application prospect.

The utility model discloses a kraft paper food packaging bag with good sealing performance, which comprises a first protective layer, a damp-proof layer and a second protective layer, the damp-proof layer is arranged in the first protective layer and is fixedly arranged on the inner wall surface of the first protective layer, the second protective layer is fixedly arranged on the inner wall surface of the damp-proof layer, and the first protective layer and the second protective layer are fixedly arranged on the inner wall surface of the damp-proof layer. According to the kraft paper food packaging bag with the good sealing performance, the first sealing strip is folded towards the second sealing strip, then the second sealing strip is folded towards the front wall face of the food packaging bag, the first sealing strip is folded towards the first sealing strip, and the second sealing strip is folded towards the front wall face of the food packaging bag; after folding is completed, the first sealing strips and the second sealing strips are fixed through mutual cooperation of the female buckles and the male buckles, air leakage of the first sealing strips or the second sealing strips in the using process is prevented, it is guaranteed that the interior of the food packaging bag does not leak air through cooperation of the two first sealing strips, and through secondary sealing of the two second sealing strips, the sealing effect is good. And the sealing performance in the food packaging bag is ensured.