Sealable gummed paper for sterile barrier system and preparation method of sealable gummed paper

Abstract

The invention belongs to the technical field of polyester gummed paper, and particularly relates to sealable gummed paper for a sterile barrier system and a preparation method of the sealable gummed paper. The invention aims to solve the problem that the air permeability and durability of the existing gummed paper are difficult to consider at the same time. The preparation method comprises the following steps: pulping bleached softwood pulp, adding auxiliaries such as oxidized nanocellulose, and sizing and forming to obtain a paper base material; performing plasma treatment on the paper base material to obtain a modified paper base material; the preparation method comprises the following steps: carrying out melt polycondensation on a dihydric alcohol monomer and a dibasic acid monomer to obtain copolyester resin, blending the copolyester resin with a functional filler, and emulsifying and dispersing to obtain a gluing agent; and ultrasonically spraying the gluing agent on the surface of the modified paper base material, and drying to form a film, thereby obtaining the sealable glued paper. The sealable gummed paper product provided by the invention has good air permeability and sealing durability at the same time, and is high in application value.

Description

Technical Field

[0001] The invention belongs to the technical field of polyester coated paper, and in particular relates to a sealable coated paper for a sterile barrier system and a preparation method thereof. Background Art

[0002] As part of the sterile barrier system, coated paper can allow sterilizing agents to penetrate during the sterilization process, while effectively preventing the invasion of microorganisms after sterilization, ensuring that medical devices remain sterile before use. This type of paper is of great significance in the medical and pharmaceutical industries, especially in preventing infection and cross-contamination. The coating of coated paper can be made of a variety of polymer materials. The coating prepared from ethylene-acrylic acid copolymer and unsaturated polyester materials can give the coated paper excellent heat-sealing properties, while providing a microbial barrier to ensure a sterile environment within the barrier, and forming an organically combined layered structure with the paper substrate of the coated paper, which has good air permeability.

[0003] In addition to good coating performance, the coated paper currently used in sterile barrier systems also needs to have excellent tear strength and durability. The pore structure design of the coated paper allows sterilization gas to pass through while preventing the penetration of microorganisms such as bacteria. At the same time, it needs to be able to withstand the mechanical stress during packaging, transportation and storage, and have good tear resistance and puncture resistance. Therefore, the pore structure and coating design of the coated paper need to meet the requirements of air permeability and barrier performance, especially to maintain consistency of performance under different sterilization methods; at the same time, while keeping the paper thin and light, its tear resistance and puncture resistance should be improved. These technical requirements constrain each other, making it difficult to obtain coated paper products that meet these technical requirements at the same time.

[0004] At present, the difficulty in balancing the air permeability and durability of existing coated papers remains a major challenge facing the industry.

[0005] To this end, a sealable glue-coated paper for a sterile barrier system and a preparation method thereof are proposed. Summary of the invention

[0006] The object of the present invention is to provide a sealable coated paper for a sterile barrier system and a preparation method thereof. The present invention firstly beats bleached softwood pulp, adds additives such as oxidized nanocellulose, and forms a paper substrate by sizing; the paper substrate is subjected to plasma treatment to obtain a modified paper substrate; a diol monomer and a dibasic acid monomer are subjected to melt polycondensation to obtain a copolyester resin, and the copolyester resin is emulsified and dispersed after being blended with a functional filler to obtain a coating agent; the coating agent is ultrasonically sprayed on the surface of the modified paper substrate, and dried to form a film to obtain a sealable coated paper.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A method for preparing a sealable coated paper for a sterile barrier system comprises the following steps:

[0009] Unless otherwise specified, the parts in the present invention refer to parts by mass, and the average molecular weight refers to the number average molecular weight.

[0010] The bleached conifer pulp is beaten and then oxidized nanocellulose is added, a wet strength agent and a sizing agent are added after dispersion, and a paper substrate is obtained after sizing and molding.

[0011] The wet strength agent is a glyoxal aqueous solution; the sizing agent includes cationic starch, alkyl ketene dimer and polyvinyl alcohol; the mass concentration of the glyoxal aqueous solution is 22wt%, and the added mass is 3% of the bleached coniferous wood pulp; the cationic starch is a quaternary ammonium cationic potato starch with an average molecular weight of 3.3×10 4 Da, the added mass is 1% of the bleached coniferous pulp; the alkyl ketene dimer is in the form of an emulsion with a solid content of 40%, and the added mass is 1% of the bleached coniferous pulp; the average molecular weight of polyvinyl alcohol is 85,000, and the added mass is 1.2% of the bleached coniferous pulp.

[0012] Among them, the bleached coniferous pulp is bleached sulfate coniferous pulp; the oxidized nanocellulose is TEMPO oxidized nanocellulose, and its average molecular weight is 3000; the added mass ratio of bleached coniferous pulp and oxidized nanocellulose is 7:1.5-2.8.

[0013] The paper substrate is treated with plasma to obtain a modified paper substrate.

[0014] The plasma treatment process is as follows: the paper substrate is treated with N 2 and O 2 The mixed gas is treated, where the gas flow rate is 50-60SLM and the discharge power density is 5W / cm 2 , the coil line speed is 25m / min, the electrode gap is 2mm; where N 2 and O 2 The flow ratio is 3:1.

[0015] The copolyester resin is obtained by melt polycondensation of diol monomers and dibasic acid monomers.

[0016] The molar ratio of the added amount of the diol monomer to the dibasic acid monomer is 1.05-1.1:1.

[0017] Among them, the diol monomers include: ethylene glycol, 1,4-butanediol and cyclohexanedimethanol; the dibasic acid monomers include: terephthalic acid, adipic acid and sebacic acid; among them, the molar ratio of the added amounts of ethylene glycol, 1,4-butanediol and cyclohexanedimethanol is 2:2.3-3.5:1.2; the molar ratio of the added amounts of terephthalic acid, adipic acid and sebacic acid is 1:1.4:0.5-0.8.

[0018] The copolyester resin and the functional filler are blended and then emulsified and dispersed to obtain a sizing agent.

[0019] The functional filler is nano-silicon dioxide with an average particle size of 80 nm. The emulsification and dispersion process is as follows: 100 parts of copolyester resin and 10 parts of deionized water are mixed, stirred at a speed of 400-600 rpm under nitrogen protection, and heated to 90-110° C. After treating for 45 minutes, the stirring speed is increased to 3500-4200 rpm, 55 parts of deionized water and 3 parts of nano-silicon dioxide are added, and after treating for 60 minutes, the stirring speed is reduced to 300 rpm and cooled to 25° C. to obtain a coating agent.

[0020] Spraying the sizing agent onto the surface of the modified paper substrate through an ultrasonic spraying process to obtain a sizing paper precursor;

[0021] The glued paper precursor is dried to form a film to obtain a sealable glued paper.

[0022] Preferably, the sizing and molding process is as follows: beating bleached coniferous wood pulp, adding oxidized nanocellulose and mixing evenly, and diluting to a solid content of 1.0-1.5% to obtain a mixed slurry; stirring the mixed slurry, adding glyoxal aqueous solution, cationic starch and alkyl ketene dimer in sequence, adjusting the pH value of the mixed slurry to 7-8.5, and then adding polyvinyl alcohol, mixing evenly and spraying the mixed slurry evenly onto a molding net, dehydrating and molding, and pressing to obtain a prefabricated paper material; drying the prefabricated paper material at 80-120°C to obtain a paper substrate.

[0023] Preferably, the melt copolymerization process is: mixing and dissolving the diol monomer and the dibasic acid monomer, adding tetrabutyl titanate accounting for 0.25% of the mass of the diol monomer, heating to 150-220° C. under nitrogen protection for reaction for 3-4 hours, heating to 240-260° C., reducing the operating pressure of the reaction system to 0.05 atm, continuing to stir and react for 2 hours, and removing the solvent to obtain a copolyester resin.

[0024] Preferably, the ultrasonic spraying process is as follows: spraying an ethyl acetate solution of isophorone diisocyanate with a mass concentration of 0.5wt% on the surface of the modified paper substrate and then drying it; passing the sizing agent through a 25μm filter head and then spraying it on the surface of the modified paper substrate at an ultrasonic frequency of 40kHz and a nitrogen gas flow pressure of 0.5-0.8psi; the distance from the nozzle to the surface of the modified paper substrate is 35mm, and the ultrasonic power is 10W, to obtain a sizing paper precursor.

[0025] Preferably, the drying film forming process is: drying the glue-coated paper precursor at 50-70° C. for 25 seconds, heating it to 80-90° C. and purging it with nitrogen for 60 seconds, cooling it to 25° C. and keeping it warm for 60 seconds to obtain the sealable glue-coated paper.

[0026] A sealable glue-coated paper for a sterile barrier system comprises: a glue layer and a modified paper substrate; the glue layer is obtained by spraying a glue agent on the surface of the modified paper substrate. The glue-coated paper product prepared by the invention has an average thickness of 0.3 mm and has good heat sealing performance and sealing durability.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. By introducing oxidized nanocellulose and bleached coniferous wood pulp to form the basis of the fiber network, and using the nano-silica filler in the coating agent to form a composite physical barrier in the coating layer, the barrier ability of the coated paper product to microorganisms is comprehensively improved, and the mechanical strength of the coated paper is guaranteed.

[0029] 2. Through the specific types and addition ratios of diol monomers and dibasic acid monomers, a hydroxyl-terminated copolyester resin was synthesized using a melt polycondensation process, which synergistically improved the adhesiveness and heat sealing properties of the adhesive, and ensured that the air permeability of the coated paper product was not affected. Different monomer selections and specific ratios give the adhesive good fluidity and non-crystallization, and with the help of ultrasonic spraying technology, highly uniform coating is achieved, resulting in a coated paper product with stable performance and high durability.

[0030] 3. The surface structure of the paper substrate is improved through the synergistic effect of oxidized nanocellulose and polyvinyl alcohol, which provides a good foundation for subsequent processing and gluing. The surface energy of the paper substrate is increased with the help of plasma treatment, and the bonding strength between the glue coating layer and the paper substrate is significantly improved. The synergistic effect of strong chemical bonding and physical adsorption from paper fibers to the polyester glue layer is achieved, ensuring extremely high interface bonding strength.

[0031] 4. By adding cationic starch and the ethyl acetate solution of isophorone diisocyanate sprayed in advance during the ultrasonic spraying process, and combining a multi-stage drying and film-forming process, uniform film formation is ensured, and the interfacial bonding force between the coating layer and the paper substrate and the sealing durability of the coated paper product are synergistically strengthened. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The present invention is a flow chart of the preparation process of the sealable coated paper. DETAILED DESCRIPTION

[0033] The technical solution of the present invention will be clearly and completely described below through some embodiments and experimental examples. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Reference Figure 1 As shown in the process flow chart, the present invention provides a sealable coated paper for a sterile barrier system and a preparation method thereof, and the technical scheme is as follows:

[0035] Example 1

[0036] The bleached conifer pulp is beaten, oxidized nanocellulose is added and mixed evenly, and the mixture is diluted to a solid content of 1.0% to obtain a mixed pulp; the mixed pulp is kept stirred, and an aqueous solution of glyoxal, cationic starch and alkyl ketene dimer are added in sequence, the pH value of the mixed pulp is adjusted to 7, and polyvinyl alcohol is added, and the mixed pulp is evenly sprayed onto a forming net after mixing, and the mixed pulp is dehydrated and formed and then pressed to obtain a prefabricated paper material; the prefabricated paper material is dried at 80°C to obtain a paper substrate.

[0037] The wet strength agent is a glyoxal aqueous solution; the sizing agent includes cationic starch, alkyl ketene dimer and polyvinyl alcohol; the mass concentration of the glyoxal aqueous solution is 22wt%, and the added mass is 3% of the bleached coniferous wood pulp; the cationic starch is a quaternary ammonium cationic potato starch with an average molecular weight of 3.3×10 4 Da, the added mass is 1% of the bleached coniferous pulp; the alkyl ketene dimer is in the form of an emulsion with a solid content of 40%, and the added mass is 1% of the bleached coniferous pulp; the average molecular weight of polyvinyl alcohol is 85,000, and the added mass is 1.2% of the bleached coniferous pulp.

[0038] Among them, the bleached coniferous pulp is bleached sulfate coniferous pulp; the oxidized nanocellulose is TEMPO oxidized nanocellulose, and its average molecular weight is 3000; the added mass ratio of bleached coniferous pulp and oxidized nanocellulose is 7:1.5.

[0039] The paper substrate is N 2 and O 2 The gas flow rate is 50SLM and the discharge power density is 5W / cm 2, the coil line speed is 25m / min, the electrode gap is 2mm; where N 2 and O 2 The flow ratio is 3:1.

[0040] The diol monomer and the dibasic acid monomer are mixed and dissolved, and tetrabutyl titanate accounting for 0.25% of the mass of the diol monomer is added, and the temperature is raised to 150° C. under nitrogen protection for reaction for 3 hours. After the temperature is raised to 240° C., the operating pressure of the reaction system is reduced to 0.05 atm, and the reaction is continued by stirring for 2 hours. After removing the solvent, a copolyester resin is obtained.

[0041] The molar ratio of the added amount of the diol monomer to the dibasic acid monomer is 1.05:1.

[0042] Among them, the diol monomers include: ethylene glycol, 1,4-butanediol and cyclohexanedimethanol; the dibasic acid monomers include: terephthalic acid, adipic acid and sebacic acid; among them, the molar ratio of the added amounts of ethylene glycol, 1,4-butanediol and cyclohexanedimethanol is 2:2.3:1.2; the molar ratio of the added amounts of terephthalic acid, adipic acid and sebacic acid is 1:1.4:0.5.

[0043] 100 parts of copolyester resin and 10 parts of deionized water were mixed, stirred at a speed of 400 rpm under nitrogen protection, and heated to 90°C. After treating for 45 minutes, the stirring speed was increased to 3500 rpm, 55 parts of deionized water and 3 parts of nano-silicon dioxide were added, and after treating for 60 minutes, the stirring speed was reduced to 300 rpm and cooled to 25°C to obtain a coating agent.

[0044] An ethyl acetate solution of isophorone diisocyanate with a mass concentration of 0.5 wt% was sprayed on the surface of the modified paper substrate and then dried. The sizing agent was processed through a 25 μm filter head and then sprayed on the surface of the modified paper substrate at an ultrasonic frequency of 40 kHz and a nitrogen gas flow pressure of 0.5 psi. The distance from the nozzle to the surface of the modified paper substrate was 35 mm, and the ultrasonic power was 10 W to obtain a sizing paper precursor.

[0045] The glue-coated paper precursor was dried at 50°C for 25 seconds, then heated to 80°C and purged with nitrogen for 60 seconds, then cooled to 25°C and kept warm for 60 seconds to obtain a sealable glue-coated paper.

[0046] Examples 2-20 are different from Example 1 in terms of operating parameters, and the specific parameter changes are summarized in Tables 1-3.

[0047] Table 1 Operation parameter changes of Examples 1-20 (I)

[0048]

[0049] Table 2 Operation parameter changes of Examples 1-20 (II)

[0050]

[0051] Table 3 Operation parameter changes of Examples 1-20 (III)

[0052]

[0053] Comparative Example 1

[0054] The difference from Example 1 is that nanocellulose is used instead of TEMPO-oxidized nanocellulose, and other process parameters remain unchanged.

[0055] Comparative Example 2

[0056] The difference from Example 1 is that no nano-silicon dioxide is added and other process parameters remain unchanged.

[0057] Comparative Example 3

[0058] The difference from Example 1 is that TEMPO-oxidized nanocellulose and nano-silicon dioxide are not added, and other process parameters remain unchanged.

[0059] Comparative Example 4

[0060] Different from Example 6, 1,4-butanediol was not added to the diol monomer, and other process parameters remained unchanged.

[0061] Comparative Example 5

[0062] Different from Example 6, sebacic acid was not added to the dibasic acid monomer, and other process parameters remained unchanged.

[0063] Comparative Example 6

[0064] The difference from Example 6 is that the molar ratio of the added amount of diol monomer and dibasic acid monomer is changed to 1.4:1, and other process parameters remain unchanged.

[0065] Comparative Example 7

[0066] The difference from Example 11 is that polyvinyl alcohol is not added and other process parameters remain unchanged.

[0067] Comparative Example 8

[0068] Different from Example 11, plasma treatment is not performed and other process parameters remain unchanged.

[0069] Comparative Example 9

[0070] The difference from Example 16 is that cationic starch is not added and other process parameters remain unchanged.

[0071] Comparative Example 10

[0072] Different from Example 16, an ethyl acetate solution of isophorone diisocyanate was sprayed on the surface of the modified paper substrate after the ultrasonic spray treatment, and other process parameters remained unchanged.

[0073] Comparative Example 11

[0074] Different from Example 16, during the drying and film-forming process, only single-stage drying at 83° C. was performed, and nitrogen was purged for 85 seconds, and other process parameters remained unchanged.

[0075] Experimental Example 1

[0076] The mechanical strength and barrier capacity of the gummed paper products prepared in Examples 1-5 and Comparative Examples 1-3 were tested, and the results are summarized in Table 4.

[0077] The test method for mechanical strength is as follows: a rectangular specimen with a width of 15 mm and a length of 200 mm is cut from the coated paper product, and its tensile strength is measured using a tensile testing machine, wherein the clamp spacing is 100 mm, and the tensile speed is 100 mm / min, and its maximum tensile force (N / m) and elongation at break (%) are recorded.

[0078] The test method for barrier capacity is as follows: a circular sample with a diameter of 60 mm is cut from the coated paper product, and 1 mL of a concentration of 1×10 7 CFU / mL of Staphylococcus aureus suspension was added dropwise to the sample surface and incubated at 37°C for 24 h before collecting the liquid in the receiving chamber for colony counting to calculate the number of microbial penetrations (CFU / mL).

[0079] Table 4 Mechanical strength and barrier capacity of the gummed paper products prepared in Examples 1-5 and Comparative Examples 1-3

[0080]

[0081] As shown in the data of Table 4, the coated paper products prepared by Examples 1-5 have good tensile strength and barrier capacity. In Comparative Example 1, nanocellulose replaces TEMPO-oxidized nanocellulose, and the maximum tensile force value is reduced to 1627N / m, and the number of microbial penetration increases to 0.1CFU / mL; in Comparative Example 2, no nanosilica is added, the maximum tensile force value is 1856N / m, and the number of microbial penetration increases to 0.4CFU / mL; in Comparative Example 3, TEMPO-oxidized nanocellulose and nanosilica are removed at the same time, and the maximum tensile force value is only 1108N / m, and the number of microbial penetration increases significantly to 1.8CFU / mL. Examples 1-5 show significant advantages in both mechanical strength and barrier capacity, which is attributed to the triple synergistic effect of oxidized nanocellulose, bleached coniferous pulp and nanosilica. The introduction of TEMPO oxidized nanocellulose effectively improves the mechanical properties of the paper substrate, directionally strengthens the basic fiber support structure provided by bleached coniferous pulp, enhances the bonding force between fiber networks, and improves the overall strength of the coated paper product; the addition of nano-silica constructs an effective physical barrier in the coating layer, significantly improving the barrier ability of the coated paper to microorganisms; the synergistic effect of the three not only ensures the mechanical strength of the coated paper, but also enables it to have excellent microbial barrier properties, thereby meeting the application requirements of the sterile barrier system.

[0082] Experimental Example 2

[0083] The heat sealing performance and air permeability of the gummed paper products prepared in Examples 6-10 and Comparative Examples 4-6 were tested, and the results are summarized in Table 5.

[0084] The test method for heat sealing performance is: cut a sample of the coated paper product with a size of 25mm×150mm, and the heat sealing parameters are: temperature 130°C, pressure 0.3MPa, time 1s; record the heat sealing strength (N / m) of the sample.

[0085] The test method for air permeability is as follows: a circular sample with a diameter of 60 mm is cut from the coated paper product, the sample is clamped in an air permeability tester, and its air permeability (mL / s) is tested within a 60s air permeability time. The operating air pressure is 200kPa, and the final air permeability (mL / (m 2 ·s)).

[0086] Table 5 Heat sealing properties and air permeability of the gummed paper products prepared in Examples 6-10 and Comparative Examples 4-6

[0087]

[0088] As shown in the data of Table 5, the heat seal strength and air permeability of the coated paper products prepared in Examples 6-10 are relatively stable. In Comparative Example 4, 1,4-butanediol is not added to the diol monomer, and the heat seal strength is reduced to 305 N / m, and the air permeability is 15.6 mL / (m2 ·s); Comparative Example 5 does not add sebacic acid to the dibasic acid monomer, the heat seal strength drops to 287N / m, and the air permeability drops to 12.5mL / (m 2 ·s); Comparative Example 6: the molar ratio of the addition amount of diol monomer and dibasic acid monomer was changed to 1.4:1, the heat seal strength dropped to 294N / m, and the air permeability increased to 20.3mL / (m 2 ·s). In summary, specific diol monomers (ethylene glycol, 1,4-butanediol and cyclohexanedimethanol) and dibasic acid monomers (terephthalic acid, adipic acid and sebacic acid) effectively achieve the effect of improving the heat sealing strength of the coated paper products. Different monomers give the copolyester resin specific molecular structure and properties, thereby optimizing the adhesion and heat sealing properties of the coating agent; at the same time, the specific ratio helps to adjust the crystallinity and melting behavior of the copolyester resin, thereby obtaining a good heat sealing effect and ensuring the air permeability of the coated paper products; the melt polycondensation process controls the synthesis of the copolyester resin, the specific monomer types give the resin a specific chemical structure, and the ratio of the monomers further adjusts the physical properties of the resin, ultimately making the coating agent have good fluidity and non-crystallization, and achieves uniform coating through the ultrasonic spraying process, obtaining a coated paper product with stable performance and high durability.

[0089] Experimental Example 3

[0090] Referring to the test methods of Experimental Examples 1 and 2, the mechanical strength and heat sealing properties of the gummed paper products prepared in Examples 11-15 and Comparative Examples 7-8 were tested, and the results are summarized in Table 6.

[0091] Table 6 Mechanical strength and heat sealing properties of the gummed paper products prepared in Examples 11-15 and Comparative Examples 7-8

[0092]

[0093] As shown in the data of Table 6, the gummed paper products prepared in Examples 11-15 have good mechanical strength and heat sealing strength. Comparative Example 7 does not add polyvinyl alcohol, and the maximum tensile force is 1804 N / m, the elongation at break is 9.2%, and the heat sealing strength is 301 N / m; Comparative Example 8 does not undergo plasma treatment, and the maximum tensile force is 1725 N / m, the elongation at break is 8.7%, and the heat sealing strength is 283 N / m. Compared with the above data, Examples 11-15 show better comprehensive performance in mechanical strength and heat sealing performance, which indicates that the combined effect of oxidized nanocellulose and polyvinyl alcohol can effectively improve the surface properties of the paper substrate and the bonding performance of the glue layer; at the same time, plasma treatment improves the wettability and adhesion of the paper substrate to the glue layer by increasing the surface energy of the paper substrate, thereby achieving strong chemical bonding and physical adsorption from paper fibers to the polyester glue layer; the synergistic effect of oxidized nanocellulose and polyvinyl alcohol improves the surface properties of the paper substrate and provides a good foundation for gluing; plasma treatment further strengthens the bonding between the glue layer and the paper substrate, and ultimately achieves a synergistic improvement in the surface smoothness of the paper substrate and the bonding strength between the glue layer and the paper substrate.

[0094] Experimental Example 4

[0095] Referring to the test method of Experimental Example 1, the sealing durability and mechanical strength of the gummed paper products prepared in Examples 16-20 and Comparative Examples 9-11 were tested, and the results are summarized in Table 7.

[0096] The test method for sealing durability is as follows: refer to the test method for heat sealing performance, cut a 25mm×150mm rectangular sample from the coated paper product, put it into a test box with a temperature of 40°C and a humidity of 75% after heat sealing, and take samples for heat sealing performance test at 0 days, 7 days, and 14 days respectively, record the heat sealing strength (N / m), and calculate the heat sealing strength retention rate corresponding to different days.

[0097] Table 7 Sealing durability and mechanical strength of the gummed paper products prepared in Examples 16-20 and Comparative Examples 9-11

[0098]

[0099] As shown in the data of Table 7, the sealing durability and mechanical strength of the coated paper products prepared in Examples 16-20 are good. For Comparative Example 9, no cationic starch is added, the heat sealing strength is 309 N / m, the 7-day heat sealing strength retention rate is 97.7%, the 14-day heat sealing strength retention rate is 89.6%, the maximum tensile force is 1915 N / m, and the elongation at break is 11.2%. For Comparative Example 10, an ethyl acetate solution of isophorone diisocyanate is sprayed on the surface of the modified paper substrate after ultrasonic spraying treatment, and the heat sealing strength is The heat sealing strength retention rate after 7 days was 93.1%, the heat sealing strength retention rate after 14 days was 81.2%, the maximum tensile force was 1842 N / m, and the elongation at break was 10.4%. In the drying and film-forming process of Comparative Example 11, only single-stage drying at 83°C was performed, and nitrogen was purged for 85s. The heat sealing strength was 288 N / m, the heat sealing strength retention rate after 7 days was 98.1%, the heat sealing strength retention rate after 14 days was 84.7%, the maximum tensile force was 1904 N / m, and the elongation at break was 9.2%.

[0100] In summary, cationic starch, as a wet strength agent, also has the functionality of a sizing agent. Its addition helps to improve the performance of the paper substrate and improve the uniformity of the adhesive layer. Spraying an ethyl acetate solution of isophorone diisocyanate before ultrasonic spraying can enhance the interfacial bonding between the adhesive layer and the paper substrate and achieve the effect of in-situ cross-linking during the spraying process. The two work synergistically to ensure the formation of a uniform adhesive film. The multi-stage drying and film-forming process can better control the volatilization rate of the solvent in the adhesive layer and reduce the defects of the adhesive film, thereby improving the sealing durability of the adhesive-coated paper product. The three work synergistically to jointly ensure the formation of a uniform adhesive film and synergistically strengthen the interfacial bonding between the adhesive layer and the paper substrate, ultimately improving the sealing durability of the adhesive-coated paper product.

[0101] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a sealable coated paper for a sterile barrier system, characterized in that: The preparation method is as follows: The bleached softwood pulp is beaten and then oxidized nanocellulose is added, a wet strength agent and a sizing agent are added after dispersion, and a paper substrate is obtained after sizing and molding; Wherein, the added mass ratio of the bleached coniferous wood pulp to the oxidized nanocellulose is 7:1.5-2.8; treating the paper substrate with plasma to obtain a modified paper substrate; The diol monomer and the dibasic acid monomer are subjected to melt polycondensation to obtain a copolyester resin; The molar ratio of the diol monomer to the dibasic acid monomer is 1.05-1.1:

1. After blending the copolyester resin and the functional filler, emulsifying and dispersing the mixture to obtain a sizing agent; Spraying the sizing agent on the surface of the modified paper substrate through an ultrasonic spraying process to obtain a sizing paper precursor; The glued paper precursor is dried to form a film to obtain a glued layer, and the glued layer and the modified paper substrate together constitute the sealable glued paper.

2. The method for preparing a sealable coated paper for a sterile barrier system according to claim 1, characterized in that: The wet strength agent is a glyoxal aqueous solution; the sizing agent includes cationic starch, alkyl ketene dimer and polyvinyl alcohol; the sizing molding process is: beating the bleached coniferous wood pulp, adding the oxidized nanocellulose and mixing evenly, and diluting to a solid content of 1.0-1.5% to obtain a mixed slurry; stirring the mixed slurry, adding the glyoxal aqueous solution, the cationic starch and the alkyl ketene dimer in sequence, adjusting the pH value of the mixed slurry to 7-8.5, and then adding the polyvinyl alcohol, mixing evenly, and then spraying the mixed slurry evenly onto a molding net, dehydrating and molding, and pressing to obtain a prefabricated paper material; drying the prefabricated paper material at 80-120°C to obtain the paper substrate.

3. The method for preparing a sealable coated paper for a sterile barrier system according to claim 1, characterized in that: The plasma treatment process is as follows: the paper substrate is treated with a mixed gas of N2 and O2, wherein the gas flow rate is 50-60 SLM and the discharge power density is 5 W / cm 2 , the coil line speed is 25m / min, and the electrode gap is 2mm.

4. The method for preparing a sealable coated paper for a sterile barrier system according to claim 1, characterized in that: The melt copolymerization process is as follows: the diol monomer and the dibasic acid monomer are mixed and dissolved, tetrabutyl titanate is added, the temperature is raised to 150-220° C. under nitrogen protection for reaction for 3-4 hours, the temperature is raised to 240-260° C., the operating pressure of the reaction system is reduced to 0.05 atm, the reaction is continued with stirring for 2 hours, and the copolyester resin is obtained after the solvent is removed.

5. The method for preparing a sealable coated paper for a sterile barrier system according to claim 4, characterized in that: The diol monomers include: ethylene glycol, 1,4-butanediol and cyclohexanedimethanol; the dibasic acid monomers include: terephthalic acid, adipic acid and sebacic acid; wherein the molar ratio of the added amounts of ethylene glycol, 1,4-butanediol and cyclohexanedimethanol is 2:2.3-3.5:1.2; the molar ratio of the added amounts of terephthalic acid, adipic acid and sebacic acid is 1:1.4:0.5-0.

8.

6. The method for preparing a sealable coated paper for a sterile barrier system according to claim 1, characterized in that: The functional filler is nano silicon dioxide; the emulsification and dispersion process is: by weight, 100 parts of the copolyester resin and 10 parts of deionized water are mixed, stirred at a speed of 400-600 rpm under nitrogen protection, and heated to 90-110° C., after treating for 45 minutes, the stirring speed is increased to 3500-4200 rpm, 55 parts of deionized water and 3 parts of the nano silicon dioxide are added, after treating for 60 minutes, the stirring speed is reduced to 300 rpm and cooled to 25° C. to obtain the coating agent.

7. The method for preparing a sealable coated paper for a sterile barrier system according to claim 1, characterized in that: The ultrasonic spraying process is as follows: spraying an ethyl acetate solution of isophorone diisocyanate with a mass concentration of 0.5wt% on the surface of the modified paper substrate and then drying it; after the sizing agent is processed through a 25μm filter head, it is sprayed on the surface of the modified paper substrate at an ultrasonic frequency of 40kHz with a nitrogen gas flow pressure of 0.5-0.8psi, the distance from the nozzle to the surface of the modified paper substrate is 35mm, and the ultrasonic power is 10W, so as to obtain the sizing paper precursor; the drying and film-forming process is as follows: drying the sizing paper precursor at 50-70°C for 25s, heating it to 80-90°C and purging it with nitrogen for 60s, cooling it to 25°C and keeping it warm for 60s to obtain the sealable sizing paper.

8. A sealable coated paper for a sterile barrier system, characterized in that: The sealable glue-coated paper is prepared by the preparation method described in any one of claims 1 to 7; the sealable glue-coated paper comprises: a glue layer and a modified paper substrate; the glue layer is obtained by spraying a glue agent on the surface of the modified paper substrate and then drying to form a film.

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