A method for preparing a composite wrapping paper, a composite wrapping paper, and a wrapping bag

Abstract

The application discloses a kind of packing paper preparation method, comprising the following steps: 1) surface embryo layer preparation: the bleaching treatment of mixed pulp is obtained by mixing camphor tree wood pulp, masson pine wood pulp and waste paper pulp, after being sequentially coated, pressed, dried, coiled and polished, surface embryo layer is obtained;2) impregnation hot-pressing treatment: surface embryo layer is prepared for use by impregnation hot-pressing treatment with resin;3) inner embryo layer preparation: the bleaching treatment of mixed pulp is obtained by mixing camphor tree wood pulp, masson pine wood pulp and waste paper pulp, after being sequentially coated, pressed, dried, coiled and polished, inner embryo layer is obtained;Before coating operation, antibacterial agent is added to mixed pulp;4) hot-rolled composite treatment: the inner embryo layer and the surface embryo layer after impregnation hot-pressing treatment are arranged with reinforcing layer, the reinforcing layer is fiber mesh layer, and hot-rolled bonding can be achieved.The application can prepare composite packing paper with good waterproofness, good strength and good antibacterial property, and the composite packing paper is suitable for preparing packaging bag of pre-packaged food.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of packaging materials, in particular to a preparation method of composite packaging paper, composite packaging paper and packaging bag. BACKGROUND

[0002] In the prior art, most of the pre-packaged food such as rice and flour is packaged by plastic bags. This packaging method is fast, convenient, and low in cost. However, the food needs to be in contact with the plastic bag for a long time, which may affect the product flavor and user experience to some extent. In order to further extend the shelf life, the prior art mostly adopts vacuum packaging to prevent the influence of external moisture on the product and reduce product oxidation and mold growth.

[0003] In order to further improve food packaging, a large amount of research and improvement has been carried out in the prior art.

[0004] A grain antibacterial packaging bag is disclosed in Chinese Patent No. CN103819837A. The packaging bag is made of an antibacterial film, which is composed of the following components by weight: polyvinyl chloride resin 60-80 parts, polyethylene resin 10-20 parts, dioctyl phthalate 18-22 parts, polypropylene glycol adipate 28-32 parts, organic modified nano calcium carbonate 2-5 parts, modified copper sulfate 2-4 parts, octadecyl ammonium chloride 3-5 parts, calcium-zinc composite stabilizer 4-6 parts, stearic acid 2-4 parts, and liquid paraffin 1.5-2.5 parts. It can effectively prevent dust and bacteria from eroding the food and has good antibacterial effect.

[0005] A preparation method of a moisture-locking layer mold-proof grain packaging bag is disclosed in Chinese Patent No. CN102416712B. An anti-aging polypropylene material is used as a protective layer; a three-layer composite oxygen barrier film composed of polypropylene / ethylene-vinyl acetate / polyethylene or polypropylene / polyvinylidene chloride / polyethylene is used as an oxygen barrier layer; SAF and ES fibers are mixed and processed by a non-woven processing method to obtain a moisture-locking layer; a non-hydrophilic polypropylene spun-bond non-woven fabric or a non-hydrophilic polypropylene / polyethylene bicomponent fiber hot-rolled non-woven fabric is used as a non-hydrophilic layer, and the bag body material is obtained by hot compounding, and then the grain packaging bag is further processed. It can inhibit the growth of mold and toxins in the bag, but its structure and composition are relatively complex, and it can inhibit bacteria in the short term, but it cannot have a long-term antibacterial effect, and the food preservation is affected.

[0006] Paper packaging is environmentally friendly and safe, but how to ensure its packaging strength, water resistance and antibacterial effect after being applied to grain packaging is a difficult and important point for research and development. SUMMARY

[0007] The technical problem solved by the present application is to provide a composite packaging paper preparation method to provide a composite packaging paper with good waterproofness, good strength and good antibacterial property.

[0008] The present application also solves the problem of providing a composite packaging paper and a packaging bag suitable for pre-packaged food.

[0009] The technical problem solved by the present application is solved by the following technical solution:

[0010] A packaging paper preparation method comprises the following steps:

[0011] 1) Surface embryo layer preparation: the bleached camphor tree wood pulp, the pine wood pulp and the waste paper pulp are mixed to obtain mixed pulp, and the mixed pulp is sequentially subjected to sizing, pressing, drying, coiling and calendering to obtain the surface embryo layer;

[0012] 2) Impregnation hot pressing treatment: the surface embryo layer is subjected to impregnation hot pressing treatment with resin for standby;

[0013] 3) Inner embryo layer preparation: the bleached camphor tree wood pulp, the pine wood pulp and the waste paper pulp are mixed to obtain mixed pulp, and the mixed pulp is sequentially subjected to sizing, pressing, drying, coiling and calendering to obtain the inner embryo layer; before the sizing operation, an antibacterial agent is added to the mixed pulp;

[0014] 4) Hot rolling composite treatment: the surface embryo layer and the inner embryo layer subjected to impregnation hot pressing treatment are arranged with a reinforcing layer, the reinforcing layer is a fiber mesh layer, and hot rolling bonding can be performed.

[0015] Further, in steps 1) and 3), the weight ratio of the camphor tree wood pulp, the pine wood pulp and the waste paper pulp is 2-3:2-3:1.

[0016] Further, in step 2), the resin is melamine modified diallyl phthalate, 0.3-0.6% agar is added to the resin by mass fraction, the initiator used is azobisisobutyronitrile, the diluent used is ethanol, and the hot pressing treatment conditions are: hot pressing temperature 115-120℃, pressure 0.1-0.15MPa, time 28-30min.

[0017] Further, in step 2), a three-stage hot pressing treatment method is adopted, the first stage hot pressing temperature is 115℃, the pressure is 0.1MPa, and the time is 5min, the second stage hot pressing temperature is 120℃, the pressure is 0.15MPa, and the time is 20min; the third stage hot pressing temperature is 115℃, the pressure is 0.1MPa, and the time is 5min.

[0018] Further, in step 3), the antibacterial agent is magnesium oxide, the mass ratio of the antibacterial agent to the mixed pulp is 0.5-1:100, the magnesium oxide is composed of nano-sized magnesium oxide particles and micro-sized magnesium oxide particles, and the specific surface area of the magnesium oxide particles is greater than 10 m 2 / g.

[0019] Further, the fiber web is a hemp fiber web, which is prepared by soaking the hemp fiber web in the antibacterial concentrated solution prepared from the leaves of Cinnamomum camphora and Platycladus orientalis and then drying.

[0020] A packaging paper is prepared by the preparation method.

[0021] A packaging bag is processed by the packaging paper.

[0022] Beneficial effects: the preparation method of the packaging paper, wherein the packaging paper is composed of an outer embryonic layer, an inner embryonic layer and a reinforcing layer, the outer embryonic layer is treated by impregnation and hot pressing, which can effectively block the water vapor from entering and has good hydrophobic effect and can effectively improve the strength, the inner embryonic layer is added with a repellent agent during preparation, the antibacterial agent is uniformly distributed on the inner embryonic layer, and the sterilization effect is durable, and the reinforcing layer is a hemp fiber web treated by a unique method, which has good effect of enhancing the overall strength, absorbing moisture and assisting sterilization.

[0023] The preparation method of the packaging paper is simple, low in production cost, and suitable for large-scale production and popularization and application.

[0024] The packaging paper prepared by the combination of raw materials and the preparation method has multiple bacteriostatic effects, appropriate tearing strength, good waterproofness, is more environmentally friendly, and can well meet the packaging needs of pre-packaged food. DETAILED DESCRIPTION

[0025] In order to make the technical means, creative features, purposes and effects of the present application easy to understand, the present application is further described below in combination with specific embodiments.

[0026] Embodiment 1

[0027] The preparation method of the packaging paper comprises the following steps:

[0028] 1) Preparation of the outer embryonic layer: bleached Cinnamomum camphora wood pulp, Pinus massoniana wood pulp and waste paper pulp are mixed in a mass ratio of 2:2:1 to obtain mixed pulp, and the mixed pulp is sequentially subjected to sizing, pressing, drying, winding and calendering to obtain the outer embryonic layer.

[0029] 2) impregnation hot-pressing treatment: the surface embryo layer is impregnated with resin for hot-pressing treatment; wherein the resin is melamine modified diallyl phthalate, 0.5% agar by mass fraction is added to the resin, the initiator used is azobisisobutyronitrile, the diluent used is ethanol, and the hot-pressing treatment conditions are as follows: a three-stage hot-pressing treatment is adopted, the first stage hot-pressing temperature is 115°C, the pressure is 0.1 MPa, and the time is 5 min, the second stage hot-pressing temperature is 120°C, the pressure is 0.15 MPa, and the time is 20 min; the third stage hot-pressing temperature is 115°C, the pressure is 0.1 MPa, and the time is 5 min.

[0030] 3) inner embryo layer preparation: the bleached camphor tree wood pulp, the masson pine wood pulp and the waste paper pulp are mixed in a mass ratio of 2:2:1 to obtain mixed pulp, and the mixed pulp is sequentially subjected to sizing, pressing, drying, winding and calendering to obtain the inner embryo layer; before the sizing operation, an antibacterial agent is added to the mixed pulp; the antibacterial agent is magnesium oxide, the mass ratio of the antibacterial agent to the mixed pulp is 0.6:100, the magnesium oxide is composed of nano-sized magnesium oxide particles and micron-sized magnesium oxide particles, and the specific surface area of the magnesium oxide particles is greater than 10 m 2 / g;

[0031] 4) hot-rolling composite treatment: the surface embryo layer and the inner embryo layer subjected to the impregnation hot-pressing treatment are laminated, and a reinforcing layer is arranged between the surface embryo layer and the inner embryo layer, the reinforcing layer is a fiber mesh layer, the fiber mesh is a hemp fiber mesh, and the hemp fiber mesh is obtained by soaking an antibacterial concentrated solution prepared from camphor leaves and Chinese arborvitae leaves and then drying; the surface embryo layer, the reinforcing layer and the inner embryo layer are hot-rolled and bonded.

[0032] The detection is carried out by the method recorded in GB / T 22865-2008, and the results are as follows: the burst strength is 420 kpa, and the longitudinal tear strength is 1350 mN. After the packaging bag containing japonica rice is sealed and placed for 25 days under the condition that the relative humidity of the environment is 65%, it is observed that there is no mold contamination and the change in the water content of the japonica rice is less than 3% after opening.

[0033] Example 2

[0034] The packaging paper preparation method described in this embodiment comprises the following steps:

[0035] 1) surface embryo layer preparation: the bleached camphor tree wood pulp, the masson pine wood pulp and the waste paper pulp are mixed in a mass ratio of 2:3:1 to obtain mixed pulp, and the mixed pulp is sequentially subjected to sizing, pressing, drying, winding and calendering to obtain the surface embryo layer;

[0036] 2) impregnation hot-pressing treatment: the surface embryo layer is impregnated with resin for hot-pressing treatment; wherein the resin is melamine modified diallyl phthalate, 0.3% agar by mass fraction is added to the resin, the initiator used is azobisisobutyronitrile, the diluent used is ethanol, and the hot-pressing treatment conditions are as follows: a three-stage hot-pressing treatment is adopted, the first stage hot-pressing temperature is 115°C, the pressure is 0.1 MPa, and the time is 5 min, the second stage hot-pressing temperature is 120°C, the pressure is 0.15 MPa, and the time is 20 min; the third stage hot-pressing temperature is 115°C, the pressure is 0.1 MPa, and the time is 5 min.

[0037] 3) inner embryo layer preparation: the bleached camphor tree wood pulp, the masson pine wood pulp and the waste paper pulp are mixed in a mass ratio of 2:3:1 to obtain mixed pulp, and the mixed pulp is sequentially subjected to sizing, pressing, drying, winding and calendering to obtain the inner embryo layer; before the sizing operation, an antibacterial agent is added to the mixed pulp; the antibacterial agent is magnesium oxide, the mass ratio of the antibacterial agent to the mixed pulp is 1:100, the magnesium oxide is composed of nano-sized magnesium oxide particles and micron-sized magnesium oxide particles, and the specific surface area of the magnesium oxide particles is greater than 10 m 2 / g;

[0038] 4) hot-rolling composite treatment: the surface embryo layer and the inner embryo layer subjected to the impregnation hot-pressing treatment are laminated, and a reinforcing layer is arranged between the surface embryo layer and the inner embryo layer, the reinforcing layer is a fiber mesh layer, the fiber mesh is a hemp fiber mesh, and the hemp fiber mesh is obtained by soaking an antibacterial concentrated solution prepared from camphor leaves and Chinese arborvitae leaves and then drying; the surface embryo layer, the reinforcing layer and the inner embryo layer are hot-rolled and bonded.

[0039] The detection is performed by the method recorded in GB / T 22865-2008, and the results are as follows: the burst strength is 412 kpa, and the longitudinal tear strength is 1325 mN. After the packaging bag containing japonica rice is sealed and placed for 25 days under the condition that the relative humidity of the environment is 65%, it is observed that there is no mold contamination and the change in the water content of the japonica rice is less than 3% after opening.

[0040] Example 3

[0041] The packaging paper preparation method described in this embodiment comprises the following steps:

[0042] 1) surface embryo layer preparation: the bleached camphor tree wood pulp, the masson pine wood pulp and the waste paper pulp are mixed in a mass ratio of 3:3:1 to obtain mixed pulp, and the mixed pulp is sequentially subjected to sizing, pressing, drying, winding and calendering to obtain the surface embryo layer;

[0043] 2) impregnation hot-pressing treatment: the surface embryo layer is impregnated with resin for hot-pressing treatment; wherein the resin is melamine modified diallyl phthalate, 0.3% agar by mass fraction is added to the resin, the initiator used is azobisisobutyronitrile, the diluent used is ethanol, and the hot-pressing treatment conditions are as follows: a three-stage hot-pressing treatment is adopted, the first stage hot-pressing temperature is 115°C, the pressure is 0.1 MPa, and the time is 5 min, the second stage hot-pressing temperature is 120°C, the pressure is 0.15 MPa, and the time is 20 min; the third stage hot-pressing temperature is 115°C, the pressure is 0.1 MPa, and the time is 5 min.

[0044] 3) inner embryo layer preparation: the bleached camphor tree wood pulp, the masson pine wood pulp and the waste paper pulp are mixed in a mass ratio of 3:3:1 to obtain mixed pulp, and the mixed pulp is sequentially subjected to sizing, pressing, drying, winding and calendering to obtain the inner embryo layer; before the sizing operation, an antibacterial agent is added to the mixed pulp; the antibacterial agent is magnesium oxide, the mass ratio of the antibacterial agent to the mixed pulp is 0.5:100, the magnesium oxide is composed of nano-sized magnesium oxide particles and micron-sized magnesium oxide particles, and the specific surface area of the magnesium oxide particles is greater than 10 m 2 / g;

[0045] 4) hot-rolling composite treatment: the surface embryo layer and the inner embryo layer subjected to the impregnation hot-pressing treatment are laminated, and a reinforcing layer is arranged between the surface embryo layer and the inner embryo layer, the reinforcing layer is a fiber mesh layer, the fiber mesh is a hemp fiber mesh, and the hemp fiber mesh is obtained by soaking an antibacterial concentrated solution prepared from camphor leaves and Chinese arborvitae leaves and then drying; the surface embryo layer, the reinforcing layer and the inner embryo layer are hot-rolled and bonded.

[0046] The detection is carried out by the method recorded in GB / T 22865-2008, and the results are as follows: the burst strength is 436 kpa, and the longitudinal tear strength is 1330 mN. After the packaging bag containing japonica rice is sealed and placed for 25 days under the condition that the relative humidity of the environment is 65%, it is observed that there is no mold contamination and the change in the water content of the japonica rice is less than 3% after opening.

[0047] Comparative Example 1

[0048] The packaging paper preparation method described in this example comprises the following steps:

[0049] 1) surface embryo layer preparation: the bleached camphor tree wood pulp, the masson pine wood pulp and the waste paper pulp are mixed in a mass ratio of 3:3:1 to obtain mixed pulp, and the mixed pulp is sequentially subjected to sizing, pressing, drying, winding and calendering to obtain the surface embryo layer;

[0050] 2) the inner ply is prepared by mixing bleached camphor tree wood pulp, masson pine wood pulp and waste paper pulp in a mass ratio of 3:3:1 to obtain mixed pulp, and then the mixed pulp is sequentially subjected to sizing, pressing, drying, winding and calendering to obtain the inner ply; before the sizing operation, an antibacterial agent is added to the mixed pulp; the antibacterial agent is magnesium oxide, the mass ratio of the antibacterial agent to the mixed pulp is 0.5:100, the magnesium oxide is composed of nano-sized magnesium oxide particles and micro-sized magnesium oxide particles, and the specific surface area of the magnesium oxide particles is greater than 10 m 2 / g;

[0051] 3) hot rolling composite treatment: the surface ply subjected to the impregnation hot pressing treatment is laminated with the inner ply, and a reinforcing layer is arranged between the surface ply and the inner ply, the reinforcing layer is a fiber web layer, the fiber web is a hemp fiber web, the hemp fiber web is obtained by soaking in an antibacterial concentrated solution prepared from camphor leaves and cypress leaves and then drying, and the surface ply, the reinforcing layer and the inner ply are hot-rolled and bonded.

[0052] The detection is carried out by the method recorded in GB / T 22865-2008, and the results are that the burst strength is 362 kpa, and the longitudinal tear strength is 1125 mN. After the packaging bag containing japonica rice is sealed and placed for 25 days under the condition that the relative humidity of the environment is 65%, it is observed that part of the packaging bag is contaminated by mold and the water content of the japonica rice changes by more than 8% after being opened.

[0053] Comparative Example 2

[0054] The packaging paper preparation method described in this example comprises the following steps:

[0055] 1) the surface ply is prepared by mixing bleached camphor tree wood pulp, masson pine wood pulp and waste paper pulp in a mass ratio of 3:3:1 to obtain mixed pulp, and then the mixed pulp is sequentially subjected to sizing, pressing, drying, winding and calendering to obtain the surface ply;

[0056] 2) impregnation hot pressing treatment: the surface ply is subjected to impregnation hot pressing treatment with a resin for standby; wherein the resin is melamine modified diallyl phthalate, the initiator used is azobisisobutyronitrile, the diluent used is ethanol, and the hot pressing treatment conditions are as follows: three-stage hot pressing treatment is adopted, the first stage hot pressing temperature is 115℃, the pressure is 0.1 MPa, and the time is 5 min, the second stage hot pressing temperature is 120℃, the pressure is 0.15 MPa, and the time is 20 min; the third stage hot pressing temperature is 115℃, the pressure is 0.1 MPa, and the time is 5 min.

[0057] 3) Inner ply preparation: the bleached camphor tree wood pulp, the pine wood pulp and the waste paper pulp are mixed according to the mass ratio of 3:3:1 to obtain mixed pulp, and the mixed pulp is sequentially subjected to sizing, pressing, drying, winding and calendering to obtain the inner ply; before the sizing operation, an antibacterial agent is added to the mixed pulp; the antibacterial agent is magnesium oxide, the mass ratio of the antibacterial agent to the mixed pulp is 0.5:100, the magnesium oxide is composed of nano-sized magnesium oxide particles and micro-sized magnesium oxide particles, and the specific surface area of the magnesium oxide particles is greater than 10 m 2 / g.

[0058] 4) Hot rolling composite treatment: the surface ply subjected to the impregnation hot pressing treatment is laminated with the inner ply, and a reinforcing layer is arranged between the surface ply and the inner ply; the reinforcing layer is a fiber web layer, the fiber web is a hemp fiber web, and the hemp fiber web is obtained by soaking the antibacterial concentrated solution prepared from camphor leaves and Chinese arborvitae leaves and then drying; the surface ply, the reinforcing layer and the inner ply are hot-rolled and bonded.

[0059] The detection is carried out by using the method recorded in GB / T 22865-2008, and the results are that the burst strength is 418 kpa, and the longitudinal tear strength is 1322 mN. After the packaging bag containing japonica rice is sealed and placed for 25 days under the condition that the relative humidity of the environment is 65%, it is observed that there is mold pollution after opening, and the water content of the japonica rice is greater than 5%.

[0060] Comparative Example 3

[0061] The preparation method of the packaging paper described in this example comprises the following steps:

[0062] 1) Surface ply preparation: the bleached camphor tree wood pulp, the pine wood pulp and the waste paper pulp are mixed according to the mass ratio of 3:3:1 to obtain mixed pulp, and the mixed pulp is sequentially subjected to sizing, pressing, drying, winding and calendering to obtain the surface ply.

[0063] 2) Impregnation hot pressing treatment: the surface ply is subjected to impregnation hot pressing treatment with a resin; wherein the resin is melamine modified diallyl phthalate, 0.3% agar is added to the resin, the initiator used is azobisisobutyronitrile, the diluent used is ethanol, and the hot pressing treatment conditions are: hot pressing temperature is 115℃, pressure is 0.15 MPa, and time is 30 min.

[0064] 3) Inner ply preparation: the bleached camphor tree wood pulp, the pine wood pulp and the waste paper pulp are mixed according to the mass ratio of 3:3:1 to obtain mixed pulp, and the mixed pulp is sequentially subjected to sizing, pressing, drying, winding and calendering to obtain the inner ply; before the sizing operation, an antibacterial agent is added to the mixed pulp; the antibacterial agent is magnesium oxide, the mass ratio of the antibacterial agent to the mixed pulp is 0.5:100, the magnesium oxide is composed of nano-sized magnesium oxide particles and micro-sized magnesium oxide particles, and the specific surface area of the magnesium oxide particles is greater than 10 m2 / g;

[0065] 4) hot rolling composite treatment: the surface embryo layer and the inner embryo layer after impregnation hot pressing treatment are combined, the surface embryo layer and the inner embryo layer are arranged with the reinforcing layer, the reinforcing layer is the fiber mesh layer, the fiber mesh is the hemp fiber mesh, the hemp fiber mesh is dried after being soaked by the antibacterial concentrate prepared from the leaves of Cinnamomum camphora and the leaves of Platycladus orientalis, and the surface embryo layer, the reinforcing layer and the inner embryo layer are hot rolled and bonded.

[0066] The detection is carried out by the method recorded in GB / T 22865-2008, and the results are that the breaking degree is 386 kpa, the longitudinal tear degree is 875 mN. After the packaging bag containing japonica rice is sealed and placed for 25 days under the condition that the relative humidity of the environment is 65%, it is observed that there is blocky mold pollution and the water content change of the japonica rice is greater than 5% after opening.

[0067] Comparative Example 4

[0068] The preparation method of the packaging paper described in this example comprises the following steps:

[0069] 1) surface embryo layer preparation: the bleached Cinnamomum camphora wood pulp, the Pinus massoniana wood pulp and the waste paper pulp are mixed in a mass ratio of 3:3:1 to obtain mixed pulp, and the mixed pulp is sequentially subjected to sizing, pressing, drying, coiling and calendering to obtain the surface embryo layer;

[0070] 2) impregnation hot pressing treatment: the surface embryo layer is impregnated and hot pressed with resin for standby; wherein the resin is melamine modified diallyl phthalate, 0.3% agar by mass is added to the resin, the initiator used is azobisisobutyronitrile, the diluent used is ethanol, and the hot pressing treatment conditions are as follows: three-stage hot pressing treatment is adopted, the first-stage hot pressing temperature is 115℃, the pressure is 0.1 MPa, and the time is 5 min; the second-stage hot pressing temperature is 120℃, the pressure is 0.15 MPa, and the time is 20 min; the third-stage hot pressing temperature is 115℃, the pressure is 0.1 MPa, and the time is 5 min.

[0071] 3) inner embryo layer preparation: the bleached Cinnamomum camphora wood pulp, the Pinus massoniana wood pulp and the waste paper pulp are mixed in a mass ratio of 3:3:1 to obtain mixed pulp, and the mixed pulp is sequentially subjected to sizing, pressing, drying, coiling and calendering to obtain the inner embryo layer; before the sizing operation, an antibacterial agent is added to the mixed pulp; the antibacterial agent is magnesium oxide, and the mass ratio of the antibacterial agent to the mixed pulp is 0.5:100, the magnesium oxide is composed of nano-sized magnesium oxide particles and micron-sized magnesium oxide particles, the specific surface area of the magnesium oxide particles is greater than 10 m 2 / g;

[0072] 4) hot rolling composite treatment: the surface embryo layer and the inner embryo layer after impregnation hot pressing treatment are combined, the surface embryo layer and the inner embryo layer are arranged with the reinforcing layer, the reinforcing layer is the fiber mesh layer, the fiber mesh is the hemp fiber mesh, the hemp fiber mesh is dried after being soaked by the antibacterial concentrate prepared from the leaves of Cinnamomum camphora and the leaves of Platycladus orientalis, and the surface embryo layer, the reinforcing layer and the inner embryo layer are hot rolled and bonded.

[0073] The results of detection by the method recorded in GB / T 22865-2008 are that the burst strength is 256 kpa, the longitudinal tear strength is 779 mN. And after the packaging bag containing japonica rice is sealed and placed for 25 days under the condition that the relative humidity of the environment is 65%, it is observed that there is a small amount of mold pollution after being opened and the water content change of the japonica rice is greater than 4%.

[0074] The above shows and describes the basic principles, main features and advantages of the present application. It should be understood by those skilled in the art that the present application is not limited by the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A method for preparing packaging paper, characterized in that: The steps include: 1) Preparation of epidermis: bleached camphor wood pulp, masson pine wood pulp, and waste paper pulp are mixed to obtain a mixed pulp, and the mixed pulp is sequentially sizing, pressing, drying, winding, and calendering to obtain the epidermis; the weight ratio of camphor wood pulp, masson pine wood pulp, and waste paper pulp is 2-3:2-3:1; 2) Immersion and hot pressing: The epidermis is impregnated and hot pressed with a resin for standby use; the resin is melamine-modified diallyl phthalate, and 0.3-0.6% by weight of agar is added to the resin. The initiator used is azobisisobutyronitrile, and the diluent used is ethanol. The hot pressing conditions are a three-stage hot pressing method. The first stage is a hot pressing temperature of 115°C, a pressure of 0.1 MPa, and a time of 5 minutes. The second stage is a hot pressing temperature of 120°C, a pressure of 0.15 MPa, and a time of 20 minutes. The third stage is a hot pressing temperature of 115°C, a pressure of 0.1 MPa, and a time of 5 minutes. 3) Preparation of mesoderm: bleached camphor wood pulp, masson pine pulp and waste paper pulp are mixed to obtain a mixed pulp, and the mixed pulp is sequentially sizing, pressing, drying, winding and calendering to obtain the mesoderm; before the sizing operation, an antibacterial agent is added to the mixed pulp; the antibacterial agent is magnesium oxide, and the mass ratio of the antibacterial agent to the mixed pulp is 0.5-1:

100. The magnesium oxide is composed of nano-sized magnesium oxide particles and micro-sized magnesium oxide particles, and the specific surface area of ​​the magnesium oxide particles is greater than 10m 2 / g; the weight ratio of camphor wood pulp, masson pine wood pulp and waste paper pulp is 2~3:2~3:1; 4) Hot-rolled composite treatment: A reinforcement layer is arranged between the epidermal layer and the endoderm layer that have been treated with impregnation and hot pressing. The reinforcement layer is a fiber mesh layer, which is hot-rolled and bonded. The fiber mesh is a hemp fiber mesh, which is made by soaking in an antibacterial concentrate prepared from camphor leaves and arborvitae leaves and then drying it.

2. A wrapping paper, characterized in that: The preparation method according to claim 1 is used for preparation.

3. A packaging bag, characterized in that: The packaging paper according to claim 2 is processed.