Method of preparing a fresh food bag

Abstract

The application discloses a preparation method of a fresh bag, comprising the following steps: S1, printing a printing film by using a printing device of a printing machine; S2, compounding the printing film and a heat-seal film by using a dry compounder, coating an anti-fog coating liquid on the heat-seal film layer of the compound film by using a networked roller to form an anti-fog layer, and obtaining a first bag piece film roll; or compounding the printing film and a heat-seal film roll with an anti-fog auxiliary agent added in the master batch by using a dry compounder, and obtaining the first bag piece film roll; S3, sending the first bag piece film roll to a curing chamber for curing, and sending out after curing; and S4, spraying a high-temperature molten resin on the surface of a dry paper base film roll by using a film sprayer, and obtaining a single-layer sprayed dry paper film roll after cooling. The packaging bag prepared by the preparation method has the beneficial effects that the bag is in a humid and breathable state, and when the bag is used for storing hairy crabs, the hairy crabs can have a relatively long survival time in the bag.

Description

Technical Field

[0001] This invention relates to the field of packaging materials, and more particularly to a method for preparing a fresh food bag. Background Technology

[0002] Chinese mitten crabs are a type of fresh food with a high mortality rate during storage and sales. In order to extend the survival time of Chinese mitten crabs during storage and sales, packaging boxes as shown in patent publication CN109367957A are commonly used to package them. However, such packaging boxes are not breathable and require an absorbent paper to be placed inside to lock in moisture. Therefore, Chinese mitten crabs still have a high mortality rate when packaged in this type of packaging box. Summary of the Invention

[0003] To address the above-mentioned problems, this invention proposes a method for preparing fresh food bags.

[0004] The technical solution adopted in this invention is as follows:

[0005] A method for preparing a fresh produce bag includes the following steps:

[0006] S1. Printing is performed on the printing film using the printing device of a printing press.

[0007] S2. A dry laminator is used to laminate the printed film and the heat-sealing film. Then, an anilox roller is used to apply an anti-fog coating liquid onto the heat-sealing layer of the laminated film to form an anti-fog layer, thus obtaining the first bag sheet film roll. Alternatively, a dry lamination process can be used to laminate the printed film with a heat-sealing film roll containing an anti-fog additive in the masterbatch, thus obtaining the first bag sheet film roll.

[0008] S3. Using a coating machine, high-temperature molten resin is coated onto the surface of the dry-process paper base film roll. After cooling, a single-layer coated dry-process paper film roll is obtained. A perforation device is used to perforate the single-layer coated dry-process paper film roll to obtain a perforated single-layer coated dry-process paper film roll; or, dry lamination is used to laminate the perforated film to the side of the single-layer coated dry-process paper away from the coating surface to obtain a perforated single-layer coated dry-process paper film roll.

[0009] S4. After applying adhesive to the PET film roll using a coating machine, the extrusion section applies high-temperature molten resin onto the adhesive surface of the PET film roll. A perforated single-layer coated dry paper film roll is then bonded to the coated surface of the PET film roll. After cooling, the film roll is wound up to obtain the second bag sheet film roll.

[0010] S5. Using a bag-making machine, the first and second bag sheet film rolls are cut and heat-sealed to form bags (i.e., fresh produce packaging bags).

[0011] In this type of packaging bag, because the first layer of film roll has ventilation holes, the entire bag is breathable. At the same time, because the second layer contains dry-laid paper, which has good water absorption and water retention properties, and because the single-layer coated dry-laid paper has been perforated, water inside the bag (which may come from the crab itself or be sprayed on later) can seep into the dry-laid paper through the holes in the single-layer coated dry-laid paper. The water absorption and water retention properties of the dry-laid paper keep the inside of the bag moist and breathable. Thus, when this type of bag is used to preserve hairy crabs, it can ensure that the hairy crabs can survive for a longer period of time inside the bag.

[0012] The specific operation of step S1 is as follows: the printing substrate is placed on the unwinding rack of the gravure printing machine, the prepared ink is poured into the ink tank of the printing machine, the printing device of the printing machine is used to print on the printing substrate, and the solvent is dried in the oven of the printing machine to obtain the printing film.

[0013] The specific operation of step S2 is as follows: the heat-sealing film is unrolled on the first substrate unwinding rack of the dry laminator, the printed film is unrolled on the second substrate unwinding rack, the prepared adhesive is poured into the adhesive tray, the adhesive is evenly coated on the heat-sealing film using an anilox roller, the solvent in the heat-sealing film adhesive is dried in the drying tunnel of the dry laminator, the heat-sealing film and the printed film are bonded together and then wound up to obtain a composite film roll, then the composite film roll is unrolled on the first substrate unwinding rack, the prepared anti-fog varnish is poured into the adhesive tray, the anti-fog varnish is evenly coated on the heat-sealing film layer of the composite film using an anilox roller, the solvent is dried in the drying tunnel of the dry laminator, and the first bag sheet roll film is obtained after being wound up by the winding unit. Alternatively, the specific operation of S2 is as follows: the heat-sealing film containing anti-fogging agent is unrolled on the first substrate unwinding rack of the dry laminator, the printed roll film is unrolled on the second substrate unwinding rack, the prepared adhesive is poured into the adhesive tray, the adhesive is evenly coated on the heat-sealing film using an anilox roller, the solvent in the heat-sealing film adhesive is dried in the drying tunnel of the dry laminator, and the heat-sealing film and the printed film are laminated together and then rolled up to obtain a composite film roll.

[0014] It should be noted that the two different methods of preparing the first bag film roll in step S2 can produce two different forms of anti-fogging bag sheets, because the anti-fogging varnish mainly serves to prevent internal fogging.

[0015] The specific operation of step S3 is as follows: the dry paper is unrolled on the unwinding rack, molten resin is poured onto the surface of the dry paper using an extruder, and after cooling, it is wound up to obtain a single-layer coated dry paper roll.

[0016] The specific operation of step S3 is as follows: place the single-layer coated dry paper on the unwinding rack of the perforation equipment, use a high-temperature steel needle to perforate the single-layer coated dry paper, and then rewind it through the winding unit to obtain a perforated single-layer coated dry paper roll.

[0017] The specific operation of step S4 is as follows: the PET film roll is unrolled on the first substrate unwinding rack, the perforated coated dry paper film roll is unrolled on the second substrate unwinding rack, the PET film roll is coated with adhesive in the coating section of the coating machine and the solvent is dried in the drying tunnel section, the molten mixed resin is coated onto the coating surface of the PET film roll by the extrusion section of the coating machine, the perforated coated dry paper film roll is bonded to the coating surface of the PET film roll that has not yet cooled, and after cooling, it is wound up by the winding unit to obtain the second bag sheet film roll.

[0018] The specific operation of step S5 is as follows: the first bag sheet film roll and the second bag sheet film roll are placed on the two unwinding frames of the bag making machine respectively. The punching device of the bag making machine punches ventilation holes on the first bag sheet. The auxiliary bracket is used to pull the zipper strip so that the zipper strip passes through the gap between the first bag sheet film roll and the second bag sheet film roll. Then, the heat sealing device is used to heat seal and fix the zipper strip, so that the first bag sheet film roll and the second bag sheet film roll form an arc-shaped bottom three-seal bag structure. Then, the bag is cut into bags of predetermined size by the die-cutting blade and finally stacked and collected.

[0019] The beneficial effects of this invention are: the bag is kept in a moist and breathable state, which ensures that the crabs can survive for a longer period of time when the bag is used to store them. Attached image description:

[0020] Figure 1 This is a simplified structural diagram of the first bag of sheets;

[0021] Figure 2 This is a simplified structural diagram of the second bag panel.

[0022] The labels for each item in the diagram are: 1. PET; 2. PE; 3. Anti-fog varnish; 4. Dry paper; 5. Adhesive; 6. Vent hole. Detailed implementation method:

[0023] The present invention will now be described in detail with reference to the accompanying drawings.

[0024] Example 1

[0025] Step 1: Unroll a 12μm thick PET film roll on the unwinding rack of a gravure printing machine, pour the prepared printing ink into the ink tank of the printing machine, print the PET film roll using the printing device of the printing machine, and dry the solvent in the oven section of the printing machine to obtain the PET printed film.

[0026] Step 2: Unroll the 12μm thick cast PE film roll on the first substrate unwinding rack of the dry laminator. Unroll the PET printed film obtained in Step 1 on the second substrate unwinding rack of the dry laminator. Pour the prepared adhesive into the adhesive tray. Use an anilox roller to evenly coat the cast PE film roll with the adhesive. Dry the solvent on the adhesive surface of the cast PE film roll in the drying tunnel of the dry laminator. In the laminating section of the dry laminator, bond the adhesive surface of the cast PE film roll with the printing surface of the PET printed film. After winding by the winding unit, a laminated film roll with a material structure of "PET / adhesive / cast PE" is obtained.

[0027] Step 3: Unroll the first substrate obtained in Step 2 onto the unwinding rack of the dry laminator for the laminated film roll. Pour the prepared anti-fog varnish into the adhesive tray. Use an anilox roller to evenly coat the cast PE surface of the laminated film roll with the anti-fog varnish. Dry the solvent in the drying tunnel of the dry laminator. After winding with the help of the winding unit, the first bag film roll with the material structure "PET1 / adhesive 5 / cast PE2 / anti-fog varnish 3" is obtained (see attached diagram for structure). Figure 1 As shown, it has ventilation holes 6). If the printing film and the heat-sealing film roll with anti-fogging agent added to the masterbatch are laminated together using dry lamination to obtain the first bag sheet film roll, then the first bag sheet film roll is made entirely of two film sheets laminated together.

[0028] Step 4: [The following appears to be a separate, unrelated section:] The weight is 50g / m³ 2 The dry-laid paper base film roll is unwound on the unwinding rack. Low-density polyethylene and metallocene polyethylene are thoroughly mixed at a 1:1 ratio using the extrusion section of the coating machine, and then heated to a high-temperature molten state before being coated onto the surface of the dry-laid paper. (The coating process control parameters are as follows: resin temperature 300℃, silicone roller pressure 3KG, cooling roller pressure 3KG, peeling roller pressure 3.5KG, pressure roller pressure 15KG, unwinding tension 5KG, winding tension 5KG, production speed 80m / min, and coating film basis weight 15g / m².) 2 This process involves creating a laminated structure of "PE / dry paper," which is then wound up by a winding unit to obtain a single-layer coated dry paper roll. The resulting single-layer coated dry paper roll is placed on the unwinding rack of a perforating device, and perforations are made in the single-layer coated dry paper using a high-temperature steel needle (perforation process control parameters are as follows: perforation temperature controlled at 86℃, perforation needle depth 4.8mm). The roll is then wound up by a winding unit to obtain a perforated single-layer coated dry paper roll. Alternatively, dry lamination can be used to bond the perforated film to the side of the single-layer coated dry paper furthest from the coated surface, resulting in a perforated single-layer coated dry paper roll.

[0029] Step 5: Unroll the 12μm thick PET film roll on the first substrate unwinding rack. Pour the prepared adhesive solution into the adhesive tray in front of the first substrate unwinding rack of the coating machine. Unroll the perforated coated dry paper film roll on the second substrate unwinding rack. Apply adhesive to the sizing section of the coating machine and dry the solvent in the drying tunnel section. Then, use the extrusion section of the coating machine to apply the molten mixed resin to the sizing surface of the PET film roll (coating parameters are the same as in Step 5). Attach the perforated coated dry paper film roll to the coating surface of the still-cooled PET film roll. After cooling, rewind the film through the winding unit to obtain the second bag sheet film roll with a material structure of "PE2 / dry paper 4 / PE2 / adhesive 5 / PET1" (see attached diagram for structure). Figure 2 (as shown in the image).

[0030] Step Six: Place the first and second bag sheet film rolls on the two unwinding racks of the bag making machine. Use the punching device of the bag making machine to punch two ventilation holes 6 on the first bag sheet. Use an auxiliary bracket to pull the zipper strip so that the zipper strip passes through the gap between the first and second bag sheet film rolls. Then use a heat sealing device to heat seal and fix the zipper strip (the heat sealing parameters of the zipper strip are controlled as follows: production speed is 20m / min-50m / min, preferably 30m / min; upper longitudinal sealing plate temperature is 130℃-155℃, preferably 140℃; lower longitudinal sealing plate temperature is 80℃; longitudinal sealing pressure is 32KG; upper transverse sealing plate temperature is 130℃-155℃, preferably 140℃; lower transverse sealing plate temperature is 80℃; transverse sealing pressure is 25KG). The first and second bag sheet film rolls form an arc-shaped bottom three-seal bag structure. Then, cut the bag into fresh food packaging bags of the predetermined size by a die-cutting die. Finally, stack and collect the bags.

[0031] Combined with appendix Figure 1 and appendix Figure 2 As shown, when the first bag sheet film roll and the second bag sheet film roll are combined to prepare a bag, the PET film is located on the outermost side in both the first bag sheet and the second bag sheet.

[0032] A storage time test for hairy crabs was conducted on the fresh food bags prepared by the method shown in Example 1 above. The test method is as follows:

[0033] A batch of hairy crabs was purchased, all from the same batch. Male crabs weighed approximately 200g net, and female crabs weighed approximately 150g net. Six crabs (3 males and 3 females) were randomly selected, marked with a marker, and weighed after marking; this weight is the first-day weight. The six crabs were placed into fresh food packaging bags prepared according to the steps in Example 1. The water-locking layer of the second bag was moistened with water to keep it moist. The bags were then sealed and stored in the refrigerator (6°C). The number of surviving crabs and the weight of all surviving crabs were recorded every other day. The daily weight loss rate and average weight loss rate of all surviving crabs were calculated. After data recording, the crabs were returned to their original packaging bags, sealed, and stored in the refrigerator (6°C) again.

[0034] Note: Loss rate = (Weight on the first day - Weight on the current day) / Weight on the first day

[0035] Comparative Example 1:

[0036] Except for not using the packaging bag in Example 1, the experimental steps are the same as in Example 1.

[0037] Comparative Example 2:

[0038] The crab packaging bags in Example 1 were replaced with commercially available absorbent paper in a moist state. The crabs were placed on the moist absorbent paper for low-temperature preservation, and the remaining experimental steps were consistent with those in Example 1.

[0039] The experimental data are shown in Table 1 and Table 2.

[0040] Table 1. Changes in the average weight loss rate of hairy crabs

[0041] 1 0.00％ 0.00％ 0.00％ 3 1.90％ 1.07％ 0.95％ 5 3.47％ 1.89％ 1.90％ 7 7.12％ 2.60％ 2.33％ 9 9.04％ 3.09％ 2.58％ 11 10.98％ 3.90％ 3.14％ 13 13.01％ 4.51％ 3.45％ 15 15.03％ 5.16％ 3.76％ 17 16.41％ 5.25％ 4.15％ 19 All dead 6.19％ 4.42％ 21 8.36％ 4.73％ 23 All dead 5.11％ 25 6.14％ 27 6.46％ 29 6.65％ 31 7.15％ 33 7.51％ 35 8.11％ 37 8.63％ 39 All dead

[0042] Table 2. Statistics on the number of surviving Chinese mitten crabs

[0043] 1 6 6 6 3 6 6 6 5 6 6 6 7 6 6 6 9 6 6 6 11 6 6 4 13 5 6 3 15 2 6 3 17 1 4 3 19 All dead 2 3 21 1 3 23 All dead 3 25 3 27 3 29 3 31 3 33 2 35 2 37 2 39 All dead

[0044] The following conclusions can be drawn from the experimental data:

[0045] Both the present invention and commercially available conventional absorbent paper can achieve the effect of preservation, but the preservation effect of the present invention is superior.

[0046] The above description is merely a preferred embodiment of the present invention and does not limit the scope of patent protection of the present invention. Any equivalent modifications made based on the content of the present invention specification, whether directly or indirectly applied to other related technical fields, are similarly included within the scope of protection of the present invention.

Claims

1. A method for preparing a fresh produce bag, characterized in that, Includes the following steps, The printing film is printed using the printing device of a printing press; The printing film and heat-sealing film are laminated using a dry laminator, and then an anti-fog coating liquid is applied to the heat-sealing layer of the composite film using an anilox roller to form an anti-fog layer, thus obtaining the first bag sheet film roll; or the printing film and heat-sealing film roll with anti-fog additive added to the masterbatch are laminated together using a dry laminator to obtain the first bag sheet film roll. High-temperature molten resin is coated onto the surface of a dry-process paper roll using a coating machine. After cooling, a single-layer coated dry-process paper roll is obtained. Then, a perforation device is used to perforate the single-layer coated dry-process paper roll to obtain a perforated single-layer coated dry-process paper roll. Alternatively, a dry lamination process is used to bond the perforated film to the side of the single-layer coated dry-process paper away from the coating surface to obtain a perforated single-layer coated dry-process paper roll. After applying adhesive to the PET film roll using a coating machine, the extrusion section applies high-temperature molten resin onto the adhesive surface of the PET film roll. A perforated single-layer coated dry paper film roll is then bonded to the coated surface of the PET film roll. After cooling, the roll is wound up to obtain the second bag sheet film roll. Ventilation holes are punched in the first bag sheet, and the zipper is passed through the gap between the first bag sheet film roll and the second bag sheet film roll. The zipper is then heat-sealed to fix the zipper, and the first bag sheet film roll and the second bag sheet film roll form an arc-shaped bottom three-seal bag structure. The bag is then cut into bags and finally stacked for collection.

2. The method for preparing a fresh produce bag as described in claim 1, characterized in that, The printing substrate is printed using the printing device of a printing press, and the solvent is dried in the oven section of the printing press to obtain a printed film.

3. The method for preparing a fresh produce bag as described in claim 1, characterized in that, Unroll the heat-sealing film and the printed film roll. Apply adhesive evenly to the heat-sealing film using an anilox roller. Dry the solvent in the adhesive of the heat-sealing film. After bonding the heat-sealing film and the printed film, roll them up to obtain a composite film roll. Then, apply anti-fog varnish evenly to the heat-sealing film layer of the composite film roll using an anilox roller. Dry the solvent and roll it up again to obtain the first bag sheet roll film. Alternatively, unfold the heat-sealing film roll containing anti-fogging agent, unfold the printed film roll, use an anilox roller to evenly coat the heat-sealing film with adhesive, dry the solvent in the heat-sealing film adhesive, and then roll up the heat-sealing film and the printed film to obtain the first bag film roll.

4. The method for preparing a fresh produce bag as described in claim 1, characterized in that, The dry-laid paper is unrolled, molten resin is poured onto its surface, and after cooling, it is wound up to obtain a single-layer coated dry-laid paper roll.

5. The method for preparing a fresh produce bag as described in claim 1, characterized in that, Perforation is made in a single-layer coated dry paper, and after winding, a perforated single-layer coated dry paper roll is obtained.

6. The method for preparing a fresh produce bag as described in claim 1, characterized in that, Unroll the PET film roll, unroll the perforated single-layer coated dry paper film roll, apply adhesive to the PET film roll and dry the solvent, then pour molten mixed resin onto the adhesive surface of the PET film roll, and attach the perforated single-layer coated dry paper film roll to the coated surface of the still-cooled PET film roll. After cooling, the film is wound up by the winding unit to obtain the second bag sheet film roll.

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