High-strength and high-transparency medical cover material paper glued by double-layer primer as well as preparation method and application of high-strength and high-transparency medical cover material paper

Abstract

The invention belongs to the technical field of medical supplies, and provides high-strength and high-transparency medical cover material paper glued by double-layer primer as well as a preparation method and application of the high-strength and high-transparency medical cover material paper. The preparation method comprises the following steps: mixing an inorganic pigment, a silane coupling agent and water to obtain an inorganic pigment dispersion liquid; mixing the inorganic pigment dispersion liquid with the primer, and carrying out secondary emulsification to obtain a secondary emulsified primer; sequentially carrying out primary gluing and secondary gluing on the secondary emulsified primer on raw paper to obtain primer paper; coating the bottom gummed paper with the surface glue, and drying to obtain the high-strength and high-permeability medical cover material paper. According to the method, the double bottom adhesive layers are constructed on the surface of the body paper, and the surface adhesive is coated on the surfaces of the bottom adhesive layers, so that the prepared medical cover material paper not only has high tensile strength and tearing strength and proper peel strength, but also has good air permeability, the strength performance of the bottom adhesive paper and the dialysis performance and the sealing performance of the cover material paper are effectively improved, and the medical cover material paper is suitable for popularization and application. And a higher-quality material is provided for medical packaging.

Description

Technical Field

[0001] The present invention relates to the technical field of medical supplies, and particularly to a high-strength and high-transparency medical cover paper with double-layer bottom glue coating, a preparation method thereof, and an application thereof. Background Art

[0002] With the development of the medical industry, the safety performance of sterile medical devices has been increasingly emphasized, and it is required that their packaging materials should have long-term excellent protection effects. As an important part of the packaging of sterile medical devices, the thermoformed sterilization packaging materials include a heat-sealing base material and a sealing cover material. Among them, as a key material, the sterile medical glue-coated cover paper not only needs to have good dialysis performance, including excellent air permeability and reliable bacteria resistance, but also needs to be compatible with various sterilization methods such as ethylene oxide, electron beam, or Co60 irradiation. Compared with the traditional method of repackaging after sterilization, the final sterilization mode of medical devices (i.e., first packaging and then implementing sterilization operations) significantly strengthens the effective control of the pollution risk of medical devices during transportation, storage, and use, and greatly improves their use safety. Thus, it can be seen that the high-strength and high-transparency sterile medical glue-coated cover paper is undoubtedly an inevitable trend and an important direction for the future development of high-end medical packaging materials. From the perspective of product characteristics, high strength is crucial for the sterile medical glue-coated cover paper, which can ensure clean peeling when the medical device packaging is unsealed and effectively prevent contamination of the medical device; while high air permeability can avoid the problem of packaging bursting due to poor air permeability during ethylene oxide sterilization.

[0003] However, currently, in terms of improving the strength performance of the bottom glue paper of medical glue-coated cover paper, it mainly relies on surface coating technology. However, this method has obvious drawbacks. Surface coating will cause a significant decrease in air permeability, thereby reducing the overall quality of the product, making such products only applicable to the low-end medical field.

[0004] Therefore, it is urgent to develop a new process to prepare ultra-high-strength and high-transparency medical cover paper to meet the requirements of medical packaging. Summary of the Invention

[0005] In view of this, the present invention provides a high-strength and high-transparency medical cover paper with double-layer bottom glue coating, a preparation method thereof, and an application thereof, so as to solve the problem that the existing preparation methods of medical cover paper cannot simultaneously take into account the strength and air permeability of the medical cover paper.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention provides a preparation method of a high-strength and high-transparency medical cover paper with double-layer bottom glue coating, comprising the following steps:

[0008] 1) Mix an inorganic pigment, a silane coupling agent, and water to obtain an inorganic pigment dispersion liquid;

[0009] 2) Mix the inorganic pigment dispersion with the base glue and perform secondary emulsification to obtain a secondary emulsified base glue;

[0010] 3) Apply the secondary emulsified base glue to the base paper successively for the first coating and the second coating to obtain a base glue paper;

[0011] 4) Coat the surface glue on the base glue paper obtained in step 3) and dry it to obtain a high-strength and high-transparency medical cover paper;

[0012] Among them, the secondary emulsified base glue includes a first secondary emulsified base glue and a second secondary emulsified base glue; when the dilution ratio of the base glue to the inorganic pigment dispersion in step 2) is 1:6 - 8, the first secondary emulsified base glue is obtained, and when the dilution ratio of the base glue to the inorganic pigment dispersion in step 2) is 1:8 - 14, the second secondary emulsified base glue is obtained;

[0013] When the first coating in step 3) is the first secondary emulsified base glue, the second coating is the second secondary emulsified base glue, and when the first coating is the second secondary emulsified base glue, the second coating is the first secondary emulsified base glue.

[0014] Preferably, in step 1), the mass ratio of the inorganic pigment to the silane coupling agent is 100:1 - 15; the solid content of the inorganic pigment dispersion is 15 - 30%.

[0015] Preferably, in step 1), the inorganic pigment includes one or more of calcium carbonate, titanium dioxide, kaolin, titanium white, and white carbon black; the silane coupling agent includes one or more of FD-7250, FD-7260, KH550, and KH560.

[0016] Preferably, in step 2), the base glue includes a modified ethylene-vinyl acetate copolymer; the secondary emulsification specifically refers to mixing the base glue with the inorganic pigment dispersion in step 1) and performing secondary emulsification; the rotation speed of the secondary emulsification is 1000 - 5000 rad / min, and the time is 30 - 60 min.

[0017] Preferably, in step 3), the total coating amount of the secondary emulsified base glue is 2.5 - 4.5 g / m 2 ; the mass ratio of the secondary emulsified base glue for the first coating to the secondary emulsified base glue for the second coating is 4:1 - 1:4.

[0018] Preferably, in step 3), drying is also independently included after the first coating and during the second coating; the drying temperature is 65 - 120 °C; the coating speeds of the first coating and the second coating are independently 30 - 80 m / min.

[0019] Preferably, the surface glue described in step 4) includes ethylene-vinyl acetate copolymer; the glue application amount of the surface glue is 4-10 g / m 2 .

[0020] The present invention also provides a high-strength and high-transparency medical cover paper coated with the above double-layer base glue prepared by the preparation method of the high-strength and high-transparency medical cover paper coated with double-layer base glue.

[0021] The present invention also provides an application of the above high-strength and high-transparency medical cover paper coated with double-layer base glue in medical packaging.

[0022] It can be seen from the above technical solutions that, compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1. The present invention uses an inorganic pigment dispersion liquid made of inorganic pigments and silane coupling agents to secondary emulsify the base glue, and through controlling the dilution ratio of the base glue and the inorganic pigment dispersion liquid, two coatings are applied on the surface of the base paper to construct a double-layer base glue layer, and then the medical cover paper prepared after coating the surface glue not only has high tensile strength, tear strength and appropriate peel strength, but also has good air permeability, can achieve clean peeling when opening the package of medical devices, avoid polluting medical devices, and at the same time solve the problem of swelling bags during ethylene oxide sterilization, effectively improving the strength performance of the base glue paper and the dialysis performance and sealing performance of the cover paper, and providing a better quality material for medical packaging. Compared with the existing medical cover paper with a single-layer base glue, the drying temperature of the single-layer coating is high, which will cause the glue to form a film, so the air permeability is low; while the double-layer coating of the present invention has a lower drying temperature, which destroys the film-forming property, so the air permeability is higher; moreover, the present invention secondary emulsifies the emulsified base glue and inorganic pigments, destroys the film-forming property, generates a porous structure, and combined with the double-layer coating, greatly improves the air permeability of the cover paper.

[0024] 2. The present invention can use several of calcium carbonate, titanium dioxide, kaolin, titanium white powder and silica as inorganic pigments. Among them, the particle sizes and specific heats of different pigments are different. The mixture of two or three of them can form a particle size gradient, improve the air permeability while ensuring the uniform distribution of particles; the mixed inorganic pigments can balance the thermal conductivity of the coating. That is, a variety of inorganic pigments can play a synergistic role to adjust the whiteness and air permeability of the coating, and at the same time endow the coating with certain antibacterial properties. The silane coupling agent can improve the adhesion and durability of the inorganic pigments and the base glue, react with the surface of the substrate to form chemical bonds, thereby enhancing the adhesion of the inorganic pigments and the substrate, and further improving the high-strength and high-transparency performance of the medical cover paper. Description of the Drawings

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained according to the provided drawings.

[0026] Figure 1 It is the peeling performance diagram of the medical cover paper prepared in Examples 1-8;

[0027] Figure 2 It is the stability test result diagram of the secondary emulsified base glue prepared in Example 8;

[0028] Figure 3 It is the surface absorption performance diagram of the base glue paper and the medical cover paper prepared in Examples 1-8;

[0029] Figure 4 It is the heat-sealing peeling effect diagram of the base glue paper and the medical cover paper prepared in Example 8. Among them, Figure 4 a in is the heat-sealing peeling performance diagram of the base glue paper, Figure 4 b in is the heat-sealing peeling performance diagram of the medical cover paper. Detailed Embodiments

[0030] The present invention provides a preparation method of a high-strength and high-transparency medical cover paper with double-layer base glue coating, including the following steps:

[0031] 1) Mix inorganic pigments, silane coupling agents and water to obtain an inorganic pigment dispersion;

[0032] 2) Mix the inorganic pigment dispersion with the base glue and perform secondary emulsification to obtain a secondary emulsified base glue;

[0033] 3) Apply the secondary emulsified base glue to the base paper successively for the first coating and the second coating to obtain a base glue paper;

[0034] 4) Coat the surface glue on the base glue paper obtained in step 3) and dry it to obtain a high-strength and high-transparency medical cover paper;

[0035] Among them, the secondary emulsified base glue includes the first secondary emulsified base glue and the second secondary emulsified base glue; when the dilution ratio of the base glue to the inorganic pigment dispersion in step 2) is 1:6-8, preferably 1:6.2-7.8, further preferably 1:6.5-7.5, and more preferably 1:7, the first secondary emulsified base glue is obtained; when the dilution ratio of the base glue to the inorganic pigment dispersion in step 2) is 1:8-14, preferably 1:9-13, further preferably 1:10-12, and more preferably 1:11, the second secondary emulsified base glue is obtained;

[0036] When the first glue application described in step 3) is the first and second emulsified primer, the second glue application is the second and second emulsified primer; when the first glue application is the second and second emulsified primer, the second glue application is the first and second emulsified primer.

[0037] In the present invention, the mass ratio of the inorganic pigment and the silane coupling agent in step 1) is 100:1 to 15, preferably 100:2 to 13, further preferably 100:3 to 10, and more preferably 100:5 to 8; the solid content of the inorganic pigment dispersion is 15 to 30%, preferably 16 to 28%, further preferably 18 to 25%, and more preferably 20 to 23%.

[0038] In the present invention, the inorganic pigment in step 1) includes one or more of calcium carbonate, titanium dioxide, kaolin, titanium white powder, and silica; the silane coupling agent includes one or more of FD-7250, FD-7260, KH550, and KH560.

[0039] In the present invention, the mixing in step 1) is preferably to first perform low-speed dispersion on the inorganic pigment, silane coupling agent, and water, and then perform high-speed homogenization; the rotation speed of the low-speed dispersion is preferably 500 to 1200 rpm, further preferably 600 to 1100 rpm, and more preferably 700 to 1000 rpm; the time of the low-speed dispersion is preferably 1 to 3 h, further preferably 1.5 to 2.5 h, and more preferably 2 h; the rotation speed of the high-speed homogenization is preferably 8000 to 10000 rpm, further preferably 8500 to 9500 rpm, and more preferably 9000 rpm, and the time of the high-speed homogenization is preferably 0.5 to 1 h, further preferably 0.6 to 0.9 h, and more preferably 0.7 h.

[0040] In the present invention, the primer in step 2) includes a modified ethylene-vinyl acetate copolymer, and the modified ethylene-vinyl acetate copolymer is obtained by purchase, and the purchased modified ethylene-vinyl acetate copolymer is already emulsified; the secondary emulsification is specifically to mix the primer with the inorganic pigment dispersion in step 1) for secondary emulsification.

[0041] In the present invention, the rotation speed of the secondary emulsification is 1000 to 5000 rad / min, preferably 1500 to 4000 rad / min, further preferably 2000 to 3500 rad / min, and more preferably 2500 to 3000 rad / min; the time of the secondary emulsification is 30 to 60 min, preferably 35 to 55 min, further preferably 40 to 50 min, and more preferably 45 min.

[0042] In the present invention, the total coating amount of the secondary emulsion primer in step 3) is 2.5 to 4.5 g / m 2 , preferably 2.8 to 4.2 g / m 2 , more preferably 3.0 to 4.0 g / m 2 , even more preferably 3.2 to 3.8 g / m 2 ; the mass ratio of the secondary emulsion primer for the first coating to the secondary emulsion primer for the second coating is 4:1 to 1:4, preferably one of 4:1, 3.5:1, 3.3:1, 3:1, 1:3, 1:3.3, 1:3.5, 1:4.

[0043] In the present invention, drying is independently included after the first coating and during the second coating in step 3); the temperature of the drying is 65 to 120 °C, preferably 70 to 115 °C, more preferably 80 to 108 °C, even more preferably 85 to 100 °C; the coating speeds of the first coating and the second coating are independently 30 to 80 m / min, preferably 32 to 70 m / min, more preferably 36 to 50 m / min, even more preferably 38 to 40 m / min.

[0044] In the present invention, the topcoat in step 4) includes ethylene-vinyl acetate copolymer; the coating amount of the topcoat is 4 to 10 g / m 2 , preferably 4.5 to 9 g / m 2 , more preferably 5 to 7 g / m 2 , even more preferably 6 g / m 2 .

[0045] In the present invention, the temperature of the drying in step 4) is preferably 95 to 105 °C, more preferably 98 to 102 °C, even more preferably 100 °C; the coating speed of the topcoat is preferably 20 to 25 m / min, more preferably 22 to 24 m / min, even more preferably 23 m / min; the length of the primer paper is the same as that of the base paper.

[0046] The present invention also provides a high-strength and high-transparency medical cover paper with double-layer primer coating prepared by the preparation method of the high-strength and high-transparency medical cover paper with double-layer primer coating described above.

[0047] The present invention also provides an application of the high-strength and high-transparency medical cover paper with double-layer primer coating described above in medical packaging.

[0048] The technical solutions provided by the present invention are described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0049] Example 1

[0050] 1) Mix calcium carbonate (particle size: 8 - 10 μm) and titanium dioxide (particle size: 150 - 200 nm) in a mass ratio of 3:0.2 to obtain an inorganic pigment. Then mix the above inorganic pigment with FD - 7250 silane coupling agent in a mass ratio of 20:1 and add water. Then disperse at a low speed for 1.5 h at a rotation speed of 1000 rpm, and then homogenize at a high speed for 0.5 h at a rotation speed of 9000 rpm to obtain an inorganic pigment dispersion with a solid content of 25%.

[0051] 2) Mix the commercial - grade emulsified modified ethylene - vinyl acetate copolymer and the inorganic pigment dispersion according to dilution ratios of 1:6 and 1:14 respectively. Then perform secondary emulsification for 30 min at a rotation speed of 1500 rad / min to obtain two secondary emulsified modified ethylene - vinyl acetate copolymer base adhesives with different dilution ratios.

[0052] 3) Coat the secondary emulsified modified ethylene - vinyl acetate copolymer base adhesive with a dilution ratio of 1:6 obtained in step 2) on the base paper using an air knife, while controlling the paper speed at 42 m / min and the drying temperature at 115 °C to form the first - layer base adhesive; then coat the secondary emulsified modified ethylene - vinyl acetate copolymer base adhesive with a dilution ratio of 1:14 obtained in step 2) on the first - layer base adhesive using an air knife, while controlling the paper speed at 70 m / min and the drying temperature at 85 °C to obtain the base - adhesive paper. Among them, the total coating amount of the secondary emulsified modified ethylene - vinyl acetate copolymer base adhesive is 3.0 g / m 2 , and the mass ratio of the two - layer secondary emulsified modified ethylene - vinyl acetate copolymer base adhesives is 3:1;

[0053] 4) Coat the ethylene - vinyl acetate copolymer surface adhesive on the base - adhesive paper obtained in step 3), while controlling the paper speed for surface - adhesive coating at 20 m / min and the drying temperature at 95 °C to obtain the medical cover - material paper. Among them, the coating amount of the surface adhesive is 6 g / m 2 .

[0054] Detect the air permeability, longitudinal / transverse tensile strength, longitudinal / transverse tear strength of the base - adhesive paper prepared in this example, and the air permeability, longitudinal / transverse tensile strength, longitudinal / transverse tear strength, and peel strength of the medical cover - material paper. Among them, the air permeability is detected using an air - permeability tester, the longitudinal / transverse tensile strength is detected using a tensile - strength tester, the longitudinal / transverse tear strength is detected using a paper - tearing - degree tester, and the peel strength is detected using an electronic tensile testing machine. The above - mentioned index detections are all carried out in accordance with the requirements and test methods of YY / T0689.7 - 2009 Sealed coated papers for use in ethylene oxide or radiation sterilization barrier systems.

[0055] After testing, the air permeability of the base glue paper prepared in this example is 220 ml / min, the longitudinal / transverse tensile strength is 111.2 N / 69.75 N, and the longitudinal / transverse tear strength is 784.83 mN / 737.46 mN. The air permeability of the medical cover paper is 135 ml / min, the longitudinal / transverse tensile strength is 115.32 N / 74.21 N, the longitudinal / transverse tear strength is 826.61 mN / 879.94 mN, and the peel force is 5.3 N.

[0056] Example 2

[0057] 1) Mix calcium carbonate (particle size 8 - 10 μm) and titanium dioxide (particle size 150 - 200 nm) in a mass ratio of 3:0.2 to obtain an inorganic pigment. Then mix the above inorganic pigment with FD - 7250 silane coupling agent in a mass ratio of 20:1 and add water. Then disperse at a low speed for 2.5 h at a rotation speed of 900 rpm, and then homogenize at a high speed for 0.5 h at a rotation speed of 9000 rpm to obtain an inorganic pigment dispersion with a solid content of 25%.

[0058] 2) Mix the modified ethylene - vinyl acetate copolymer (the same as in Example 1) and the inorganic pigment dispersion according to dilution ratios of 1:6 and 1:14 respectively, and then perform secondary emulsification for 30 min at a rotation speed of 1500 rad / min to obtain two secondary emulsified modified ethylene - vinyl acetate copolymer base glues with different dilution ratios.

[0059] 3) Coat the secondary emulsified modified ethylene - vinyl acetate copolymer base glue with a dilution ratio of 1:14 obtained in step 2) on the base paper using an air knife, while controlling the vehicle speed at 70 m / min and the drying temperature at 85 °C to form the first layer of base glue; then coat the secondary emulsified modified ethylene - vinyl acetate copolymer base glue with a dilution ratio of 1:6 obtained in step 2) on the first layer of base glue using an air knife, while controlling the vehicle speed at 42 m / min and the drying temperature at 115 °C to obtain the base glue paper. Among them, the total coating amount of the secondary emulsified modified ethylene - vinyl acetate copolymer base glue is 3.0 g / m 2 , and the mass ratio of the two layers of secondary emulsified modified ethylene - vinyl acetate copolymer base glue is 1:3;

[0060] 4) Coat the ethylene - vinyl acetate copolymer surface glue on the base glue paper obtained in step 3), while controlling the vehicle speed of surface glue coating at 20 m / min and the drying temperature at 95 °C to obtain the medical cover paper. Among them, the coating amount of the surface glue is 6 g / m 2 .

[0061] Perform performance testing on the base glue paper and medical cover paper prepared in this example using the same testing method as in Example 1.

[0062] After testing, the air permeability of the base adhesive paper prepared in this example is 180 ml / min, the longitudinal / transverse tensile strength is 106.63 N / 65.27 N, and the longitudinal / transverse tear strength is 832.85 mN / 852.61 mN. The air permeability of the medical cover paper is 100 ml / min, the longitudinal / transverse tensile strength is 116.30 N / 75.68 N, the longitudinal / transverse tear strength is 845.63 mN / 897.53 mN, and the peel force is 7.2 N.

[0063] Example 3

[0064] 1) Mix calcium carbonate (particle size 8 - 10 μm), kaolin (particle size 2 - 3 μm) and titanium dioxide (particle size 150 - 200 nm) according to a mass ratio of 3:1:0.2 to obtain an inorganic pigment. Then mix the above inorganic pigment with FD - 7260 silane coupling agent according to a mass ratio of 10:1 and add water. Then disperse at a low speed for 2.5 h at a rotation speed of 900 rpm, and then homogenize at a high speed for 0.5 h at a rotation speed of 9000 rpm to obtain an inorganic pigment dispersion with a solid content of 25%.

[0065] 2) Mix the modified ethylene - vinyl acetate copolymer (the same as in Example 1) with the inorganic pigment dispersion according to dilution ratios of 1:6 and 1:12 respectively. Then perform secondary emulsification for 45 min at a rotation speed of 2000 rad / min to obtain two secondary emulsified modified ethylene - vinyl acetate copolymer base adhesives with different dilution ratios.

[0066] 3) Coat the secondary emulsified modified ethylene - vinyl acetate copolymer base adhesive with a dilution ratio of 1:6 obtained in step 2) on the base paper using an air knife, while controlling the vehicle speed at 42 m / min and the drying temperature at 115 °C to form the first - layer base adhesive; then coat the secondary emulsified modified ethylene - vinyl acetate copolymer base adhesive with a dilution ratio of 1:12 obtained in step 2) on the first - layer base adhesive using an air knife, while controlling the vehicle speed at 65 m / min and the drying temperature at 90 °C to obtain the base adhesive paper. Among them, the total coating amount of the secondary emulsified modified ethylene - vinyl acetate copolymer base adhesive is 3.1 g / m 2 , and the mass ratio of the two - layer secondary emulsified modified ethylene - vinyl acetate copolymer base adhesives is 2.8:1;

[0067] 4) Coat the ethylene - vinyl acetate copolymer surface adhesive on the base adhesive paper obtained in step 3), while controlling the vehicle speed for surface - adhesive coating at 20 m / min and the drying temperature at 95 °C to obtain the medical cover paper. Among them, the coating amount of the surface adhesive is 6 g / m 2 .

[0068] Perform performance testing on the base adhesive paper and medical cover paper prepared in this example using the same testing method as in Example 1.

[0069] After testing, the air permeability of the base glue paper prepared in this example is 200 ml / min, the longitudinal / transverse tensile strength is 106.63 N / 65.27 N, and the longitudinal / transverse tear strength is 832.85 mN / 852.61 mN. The air permeability of the medical cover paper is 120 ml / min, the longitudinal / transverse tensile strength is 116.30 N / 75.68 N, the longitudinal / transverse tear strength is 845.63 mN / 897.53 mN, and the peel force is 5.5 N.

[0070] Example 4

[0071] 1) Calcium carbonate (particle size 8 - 10 μm), silica (particle size 5 - 8 μm) and titanium dioxide (particle size 150 - 200 nm) are mixed according to a mass ratio of 3:1:0.2 to obtain an inorganic pigment. Then, the above inorganic pigment and KH560 silane coupling agent are mixed according to a mass ratio of 100:7 and water is added. Then, it is dispersed at a low speed for 2 h at a rotation speed of 500 rpm, and then homogenized at a high speed for 0.8 h at a rotation speed of 8000 rpm to obtain an inorganic pigment dispersion with a solid content of 20%.

[0072] 2) The modified ethylene-vinyl acetate copolymer (the same as in Example 1) and the inorganic pigment dispersion are mixed according to dilution ratios of 1:8 and 1:10 respectively, and then secondary emulsification is carried out for 40 min at a rotation speed of 2000 rad / min to obtain two secondary emulsified modified ethylene-vinyl acetate copolymer base glues with different dilution ratios.

[0073] 3) The secondary emulsified modified ethylene-vinyl acetate copolymer base glue with a dilution ratio of 1:8 obtained in step 2) is coated on the base paper by an air knife, while controlling the vehicle speed at 45 m / min and the drying temperature at 115 °C to form the first layer of base glue; then, the secondary emulsified modified ethylene-vinyl acetate copolymer base glue with a dilution ratio of 1:10 obtained in step 2) is coated on the first layer of base glue by an air knife, while controlling the vehicle speed at 60 m / min and the drying temperature at 95 °C to obtain the base glue paper, where the total coating amount of the secondary emulsified modified ethylene-vinyl acetate copolymer base glue is 3.5 g / m 2 , and the mass ratio of the two layers of secondary emulsified modified ethylene-vinyl acetate copolymer base glue is 2.5:1;

[0074] 4) The ethylene-vinyl acetate copolymer top glue is coated on the base glue paper obtained in step 3), while controlling the vehicle speed for top glue coating at 20 m / min and the drying temperature at 95 °C to obtain the medical cover paper, where the coating amount of the top glue is 6 g / m 2 .

[0075] The base glue paper and medical cover paper prepared in this example are subjected to performance testing using the same testing method as in Example 1.

[0076] After testing, the air permeability of the base glue paper prepared in this example is 210 ml / min, the longitudinal / transverse tensile strength is 119.30 N / 71.92 N, and the longitudinal / transverse tear strength is 842.67 mN / 912.83 mN. The air permeability of the medical cover paper is 115 ml / min, the longitudinal / transverse tensile strength is 121.70 N / 70.2 N, the longitudinal / transverse tear strength is 854.61 mN / 941.95 mN, and the peel force is 4.5 N.

[0077] Example 5

[0078] 1) Mix calcium carbonate (particle size 8 - 10 μm), fumed silica (particle size 5 - 8 μm) and titanium dioxide (particle size 150 - 200 nm) in a mass ratio of 1:1:0.2 to obtain an inorganic pigment. Then mix the above inorganic pigment with KH560 silane coupling agent in a mass ratio of 25:2 and add water. Then disperse at a low speed for 1.5 h at a rotation speed of 1000 rpm, and then homogenize at a high speed for 1.5 h at a rotation speed of 8000 rpm to obtain an inorganic pigment dispersion with a solid content of 20%.

[0079] 2) Mix the modified ethylene-vinyl acetate copolymer (same as in Example 1) and the inorganic pigment dispersion according to dilution ratios of 1:6 and 1:10 respectively. Then perform secondary emulsification for 45 min at a rotation speed of 2000 rad / min to obtain two secondary emulsified modified ethylene-vinyl acetate copolymer base glues with different dilution ratios.

[0080] 3) Coat the secondary emulsified modified ethylene-vinyl acetate copolymer base glue with a dilution ratio of 1:6 obtained in step 2) on the base paper using an air knife, while controlling the vehicle speed at 42 m / min and the drying temperature at 115 °C to form the first layer of base glue; then coat the secondary emulsified modified ethylene-vinyl acetate copolymer base glue with a dilution ratio of 1:10 obtained in step 2) on the first layer of base glue using an air knife, while controlling the vehicle speed at 60 m / min and the drying temperature at 95 °C to obtain the base glue paper, where the total coating amount of the secondary emulsified modified ethylene-vinyl acetate copolymer base glue is 3.6 g / m 2 , and the mass ratio of the two layers of secondary emulsified modified ethylene-vinyl acetate copolymer base glue is 2.3:1;

[0081] 4) Coat the ethylene-vinyl acetate copolymer surface glue on the base glue paper obtained in step 3), while controlling the vehicle speed of surface glue coating at 20 m / min and the drying temperature at 95 °C to obtain the medical cover paper, where the coating amount of the surface glue is 6 g / m 2 .

[0082] Perform performance testing on the base glue paper and medical cover paper prepared in this example using the same testing method as in Example 1.

[0083] After detection, the air permeability of the base glue paper prepared in this example is 230 ml / min, the longitudinal / transverse tensile strength is 123.50 N / 70.6 N, and the longitudinal / transverse tear strength is 737.52 mN / 835.83 mN. The air permeability of the medical cover paper is 117 ml / min, the longitudinal / transverse tensile strength is 125.61 N / 77.82 N, the longitudinal / transverse tear strength is 862.91 mN / 929.15 mN, and the peeling force is 3.5 N.

[0084] Example 6

[0085] 1) Mix calcium carbonate (particle size 8 - 10 μm), silica white (particle size 5 - 8 μm) and titanium dioxide (particle size 150 - 200 nm) according to a mass ratio of 1:1:0.2 to obtain an inorganic pigment. Then mix the above inorganic pigment with KH550 silane coupling agent according to a mass ratio of 20:3 and add water. Then disperse at a low speed of 600 rpm for 2 h, and then homogenize at a high speed of 10000 rpm for 1 h to obtain an inorganic pigment dispersion with a solid content of 18%.

[0086] 2) Mix the modified ethylene-vinyl acetate copolymer (the same as in Example 1) with the inorganic pigment dispersion according to a dilution ratio of 1:8, and then perform secondary emulsification at a speed of 2500 rad / min for 45 min to obtain a secondary emulsified modified ethylene-vinyl acetate copolymer base glue with a dilution ratio of 1:8.

[0087] 3) Coat the secondary emulsified modified ethylene-vinyl acetate copolymer base glue with a dilution ratio of 1:8 obtained in step 2) on the base paper using an air knife, while controlling the vehicle speed at 45 m / min and the drying temperature at 105 °C to form the first layer of base glue; then coat the secondary emulsified modified ethylene-vinyl acetate copolymer base glue with a dilution ratio of 1:8 obtained in step 2) on the first layer of base glue using an air knife, while controlling the vehicle speed at 45 m / min and the drying temperature at 105 °C to obtain the base glue paper. Among them, the total coating amount of the secondary emulsified modified ethylene-vinyl acetate copolymer base glue is 3.5 g / m 2 , and the mass ratio of the two layers of secondary emulsified modified ethylene-vinyl acetate copolymer base glue is 1:1;

[0088] 4) Coat the ethylene-vinyl acetate copolymer top glue on the base glue paper obtained in step 3), while controlling the vehicle speed of top glue coating at 20 m / min and the drying temperature at 95 °C to obtain the medical cover paper. Among them, the coating amount of the top glue is 6 g / m 2 .

[0089] Perform performance detection on the base glue paper and medical cover paper prepared in this example using the same detection method as in Example 1.

[0090] After testing, the air permeability of the base glue paper prepared in this example is 230 ml / min, the longitudinal / transverse tensile strength is 127.60 N / 74.41 N, and the longitudinal / transverse tear strength is 869.22 mN / 976.81 mN. The air permeability of the medical cover paper is 125 ml / min, the longitudinal / transverse tensile strength is 121.90 N / 67.74 N, the longitudinal / transverse tear strength is 902.75 mN / 981.97 mN, and the peel force is 3.8 N.

[0091] Example 7

[0092] 1) Mix fumed silica (particle size 5 - 8 μm) and titanium dioxide (particle size 150 - 200 nm) in a mass ratio of 5:1 to obtain an inorganic pigment. Then mix the above inorganic pigment with KH550 silane coupling agent in a mass ratio of 25:3 and add water. Then disperse at a low speed for 2.5 h at a rotation speed of 1100 rpm, and then homogenize at a high speed for 1 h at a rotation speed of 9000 rpm to obtain an inorganic pigment dispersion with a solid content of 28%.

[0093] 2) Mix the modified ethylene-vinyl acetate copolymer (same as in Example 1) with the inorganic pigment dispersion at a dilution ratio of 1:8, and then perform secondary emulsification for 45 min at a rotation speed of 3000 rad / min to obtain a secondary emulsified modified ethylene-vinyl acetate copolymer base glue with a dilution ratio of 1:8.

[0094] 3) Coat the secondary emulsified modified ethylene-vinyl acetate copolymer base glue with a dilution ratio of 1:8 obtained in step 2) on the base paper using an air knife, while controlling the vehicle speed at 45 m / min and the drying temperature at 105 °C to form the first layer of base glue; then coat the secondary emulsified modified ethylene-vinyl acetate copolymer base glue with a dilution ratio of 1:8 obtained in step 2) on the first layer of base glue using an air knife, while controlling the vehicle speed at 45 m / min and the drying temperature at 105 °C to obtain the base glue paper. Among them, the total coating amount of the secondary emulsified modified ethylene-vinyl acetate copolymer base glue is 3.4 g / m 2 , and the mass ratio of the two layers of secondary emulsified modified ethylene-vinyl acetate copolymer base glue is 1:1;

[0095] 4) Coat the ethylene-vinyl acetate copolymer surface glue on the base glue paper obtained in step 3), while controlling the vehicle speed of surface glue coating at 20 m / min and the drying temperature at 95 °C to obtain the medical cover paper. Among them, the coating amount of the surface glue is 6 g / m 2 .

[0096] Perform performance testing on the base glue paper and medical cover paper prepared in this example using the same testing method as in Example 1.

[0097] After testing, the air permeability of the base glue paper prepared in this example is 195 ml / min, the longitudinal / transverse tensile strength is 118.80 N / 75.27 N, and the longitudinal / transverse tear strength is 815.91 mN / 941.44 mN. The air permeability of the medical cover paper is 120 ml / min, the longitudinal / transverse tensile strength is 117.50 N / 65.70 N, the longitudinal / transverse tear strength is 899.59 mN / 910.06 mN, and the peel force is 6.8 N.

[0098] Example 8

[0099] 1) Mix silica white (particle size 5 - 8 μm) and titanium dioxide (particle size 150 - 200 nm) in a mass ratio of 5:1 to obtain an inorganic pigment. Then mix the above inorganic pigment with KH550 silane coupling agent in a mass ratio of 25:3 and add water. Then disperse it at a low speed for 2.5 h at a rotation speed of 1100 rpm, and then homogenize it at a high speed for 1 h at a rotation speed of 9000 rpm to obtain an inorganic pigment dispersion with a solid content of 25.21%.

[0100] 2) Mix the modified ethylene-vinyl acetate copolymer (the same as in Example 1) and the inorganic pigment dispersion according to dilution ratios of 1:6 and 1:14 respectively. Then perform secondary emulsification for 45 min at a rotation speed of 3000 rad / min to obtain two kinds of secondary emulsified modified ethylene-vinyl acetate copolymer base glues with different dilution ratios.

[0101] 3) Coat the secondary emulsified modified ethylene-vinyl acetate copolymer base glue with a dilution ratio of 1:6 obtained in step 2) on the base paper using an air knife, while controlling the vehicle speed at 42 m / min and the drying temperature at 115 °C to form the first layer of base glue; then coat the secondary emulsified modified ethylene-vinyl acetate copolymer base glue with a dilution ratio of 1:14 obtained in step 2) on the first layer of base glue using an air knife, while controlling the vehicle speed at 70 m / min and the drying temperature at 85 °C to obtain the base glue paper. Among them, the total coating amount of the secondary emulsified modified ethylene-vinyl acetate copolymer base glue is 3.0 g / m 2 , and the mass ratio of the two layers of secondary emulsified modified ethylene-vinyl acetate copolymer base glue is 3:1;

[0102] 4) Coat the ethylene-vinyl acetate copolymer surface glue on the base glue paper obtained in step 3), while controlling the vehicle speed of surface glue coating at 20 m / min and the drying temperature at 95 °C to obtain the medical cover paper. Among them, the coating amount of the surface glue is 6 g / m 2 .

[0103] Perform performance testing on the base glue paper and medical cover paper prepared in this example using the same testing method as in Example 1.

[0104] After testing, the air permeability of the base adhesive paper prepared in this example is 205 ml / min, the longitudinal / transverse tensile strength is 128.37 N / 75.60 N, and the longitudinal / transverse tear strength is 873.45 mN / 1040.43 mN. The air permeability of the medical cover paper is 117 ml / min, the longitudinal / transverse tensile strength is 121.36 N / 70.60 N, the longitudinal / transverse tear strength is 910.06 mN / 1014.66 mN, and the peel force is 6.5 N.

[0105] The absorption properties of the base adhesive paper and the absorption and peel properties of the medical cover paper prepared in Examples 1 to 8 were tested; among them, the above indicators were all tested according to the requirements and test methods of YY / T 0689.7-2009 Sealable coated paper for the production of ethylene oxide or radiation sterilization barrier systems. The test results are as Figure 1 and Figure 3 shown. It can be seen from the peel property diagram in Figure 1 that the peel force of the medical coated cover paper is stably maintained in the ideal range of 3.5 - 6.2 N. This performance index fully meets the dual requirements of medical device packaging for sealing reliability and opening convenience, ensuring the packaging seal integrity and ensuring that the paper layer will not be damaged during opening. By optimizing the coating formula (such as Examples 3, 7, and 8), the peel force fluctuation range can be further reduced to 4.0 - 5.5 N, while maintaining a high air permeability of about 120 mL / min. This technical solution has been successfully applied to the production of multi-layer composite materials such as dialysis paper, significantly improving the product consistency and clinical use safety; it can be seen from the absorption property diagram in Figure 3 that there are significant differences in the water absorption properties between the base adhesive paper and the medical coated cover paper: the Cobb value of the base adhesive paper is maintained at 15.5 ± 0.5 g / m 2 , indicating that it retains a moderate pore structure and is suitable as an intermediate layer to balance air permeability and barrier properties; while the Cobb value of the medical coated cover paper is as low as 5.5 ± 0.6 g / m 2 , confirming its excellent coating density and fully meeting the liquid barrier requirements of medical device packaging. The stable values of both (the fluctuation ranges are controlled within ±0.5 and ±0.6 respectively) indicate that the existing process has reached a good level, providing a more reliable solution for high-end medical device packaging. Follow-up research can focus on developing nano-composite coating technology to optimize air permeability while maintaining low water absorption.

[0106] The stability of the inorganic pigment dispersion with a solid content of 25.21% in Example 8 was tested. Among them, the specific method for stability testing is: for the inorganic pigment dispersion placed for different times, take the bottom sample to measure the solid content and compare it with the initial solid content. If the solid content is close, it indicates that the inorganic pigment dispersion is stable and there is no obvious sedimentation phenomenon. The test results are as Figure 2As shown, the inorganic pigment dispersion exhibits excellent stability within a 42-hour aging period, with a solid content in the range of approximately 25%, and no obvious phase separation or sedimentation occurs. This excellent stability is mainly attributed to the optimized emulsion system design and precise process parameter control, making it particularly suitable for the continuous production requirements of medical packaging materials.

[0107] The heat-sealing and peeling effect diagrams of the base adhesive paper and the medical cover material paper prepared in Example 8 are as Figure 4 shown. As can be seen from Figure 4 it, after heat-sealing, the peeling surface of the base adhesive paper is incomplete, while the medical coated cover material paper (with an air permeability of 117 ml / min) shows a complete peeling interface, and the peeling force is stable at 4.5 N, which fully meets the requirements of actual production applications and medical device packaging standards.

[0108] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A preparation method of a high-strength and high-transparency medical cover paper with double-layer base glue coating, characterized in that, It includes the following steps: 1) Mix an inorganic pigment, a silane coupling agent and water to obtain an inorganic pigment dispersion; 2) Mix the inorganic pigment dispersion with a base glue and perform secondary emulsification to obtain a secondary emulsified base glue; 3) Apply the secondary emulsified base glue to the base paper successively for the first coating and the second coating to obtain a base glue paper; 4) Coat the surface glue on the base glue paper obtained in step 3) and dry it to obtain a high-strength and high-transparency medical covering paper; Among them, the secondary emulsified base glue includes a first secondary emulsified base glue and a second secondary emulsified base glue; when the dilution ratio of the base glue to the inorganic pigment dispersion in step 2) is 1:6 - 8, the first secondary emulsified base glue is obtained, and when the dilution ratio of the base glue to the inorganic pigment dispersion in step 2) is 1:8 - 14, the second secondary emulsified base glue is obtained; When the first coating in step 3) is the first secondary emulsified base glue, the second coating is the second secondary emulsified base glue, and when the first coating is the second secondary emulsified base glue, the second coating is the first secondary emulsified base glue.

2. The preparation method of a high-strength and high-transparency medical cover paper with double-layer base glue coating according to claim 1, characterized in that, In step 1), the mass ratio of the inorganic pigment to the silane coupling agent is 100:1 - 15; The solid content of the inorganic pigment dispersion is 15 - 30%.

3. The preparation method of a high-strength and high-transparency medical cover paper with double-layer primer coating according to claim 2, characterized in that, In step 1), the inorganic pigment includes one or more of calcium carbonate, titanium dioxide, kaolin, titanium white and white carbon black; The silane coupling agent includes one or more of FD-7250, FD-7260, KH550, KH560.

4. The preparation method of a high-strength and high-transparency medical lid material paper with double-layer base glue coating according to any one of claims 1 to 3, characterized in that, In step 2), the base glue includes a modified ethylene-vinyl acetate copolymer; The secondary emulsification specifically refers to mixing the base glue with the inorganic pigment dispersion in step 1) and performing secondary emulsification; The rotation speed of the secondary emulsification is 1000 - 5000 rad / min, and the time is 30 - 60 min.

5. The preparation method of a high-strength and high-transparency medical cover paper with double-layer base glue coating according to claim 4, characterized in that, The total amount of the secondary emulsified primer applied in step 3) is 2.5 to 4.5 g / m 2 ; The mass ratio of the secondary emulsified base glue for the first coating to the secondary emulsified base glue for the second coating is 4:1 - 1:

4.

6. The preparation method of a high-strength and high-transparency medical cover paper with double-layer base glue coating according to claim 5, characterized in that, In step 3), drying is also independently included during the first coating and the second coating; the drying temperature is 65 - 120°C; the coating speeds of the first coating and the second coating are independently 30 - 80 m / min.

7. The preparation method of a high-strength and high-transparency medical cover paper with double-layer base glue coating according to claim 6, characterized in that, In step 4), the surface glue includes an ethylene-vinyl acetate copolymer; The glue application amount of the surface glue is 4 to 10 g / m 2 .

8. A high-strength and high-transparency medical covering paper with double-layer base glue coating prepared by the preparation method of a high-strength and high-transparency medical covering paper with double-layer base glue coating according to any one of claims 1 - 7.

9. Application of the high-strength and high-transparency medical covering paper with double-layer base glue coating according to claim 8 in medical packaging.

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