TPU nonwoven production process

Abstract

The present invention relates to the technical field of nonwoven fabrics, and specifically to a TPU nonwoven fabric production process, comprising the following steps: using solvent-resistant TPU particles and epoxy resin particles to melt and blend to form a spinning solution; using a melt-blowing method to spread a web on a web-forming machine, then soaking it in acetone without tension to dissolve and remove the epoxy resin; then hot-air consolidating and winding it to obtain a melt-blown inner layer; unwinding the melt-blown inner layer, subjecting it to plasma treatment, and then entering a web-forming machine for composite spinning using polyether TPU particles as the skin material and polyester TPU particles as the core material; collecting the melt-blown inner layer on the surface of the web-forming machine to obtain a melt-blown surface layer; treating the surface layer and the inner layer with collagen solution as a hydroentanglement medium; and finally hot-air drying, trimming, and winding it. The present invention improves the antibacterial and skin-friendly properties of the melt-blown inner layer and helps to enhance the bonding strength between the surface layer and the inner layer. The nonwoven fabric of the present invention can be used for health-related purposes such as medical care / nursing, mainly disposable items, such as diapers, sanitary napkins, gauze, bandages, masks, gloves, and wound dressings.

Description

Technical Field

[0001] The present invention relates to the technical field of nonwoven fabrics, and in particular to a production process of TPU nonwoven fabrics. Background Art

[0002] Thermoplastic polyurethane nonwoven fabric (TPU nonwoven fabric) is a non-toxic and harmless environmentally friendly material. It is made of sheets, webs or pads made by directional or randomly arranged fibers, which are combined with each other through friction, adhesion or bonding, or a combination of the above methods. It has the advantages of good elasticity, high lightness, moisture permeability and waterproofness, and is harmless to human skin. It is widely used in clothing fabrics, medical and health care, leather and other fields.

[0003] A Chinese public document (CN1445390A) discloses a meltblown method for producing polyurethane elastic nonwoven fabrics. The method comprises the following steps: polyurethane particles are fed into a screw extruder, heated and melted at 180-260°C, and then extruded from a spinneret in a die head. Hot air streams blown from both sides of the spinneret stretch the melt into ultrafine fibers, which then self-bond to form the polyurethane elastic nonwoven fabric. However, TPU particles themselves lack antimicrobial properties and cannot meet the antimicrobial requirements of nonwoven fabrics for medical products such as bandages. Furthermore, for composite nonwoven fabrics, the bonding between the fibers in the layers primarily relies on their own adhesion, which contributes to improved peel strength. However, no prior art approach has addressed both the antimicrobial and peel strength issues. Summary of the Invention

[0004] The object of the present invention is to provide a TPU nonwoven fabric production process that simultaneously meets the technical requirements of improving antibacterial properties and peel strength.

[0005] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

[0006] The TPU nonwoven production process specifically includes the following steps:

[0007] S1. Solvent-resistant TPU particles and epoxy resin particles are melted together to form a spinning solution. After laying the web on a web-forming machine using a melt-blowing method, the web is tension-free soaked in acetone organic solvent to dissolve and remove the epoxy resin. The web is then hot-dried, consolidated, bonded, and rolled up to obtain a melt-blown inner layer.

[0008] S2, the meltblown inner layer is unwound and plasma treated before entering the web forming machine, where polyether TPU particles are used as the skin material and polyester TPU particles are used as the core material for composite spinning. The meltblown inner layer surface is collected at the web forming machine to obtain the meltblown surface layer;

[0009] S3. Using collagen liquid as the spunlace medium to process the meltblown surface layer and meltblown inner layer laminated in step S2, and finally drying with hot air, trimming and rolling up.

[0010] Preferably, the mass ratio of the solvent-resistant TPU particles to the epoxy resin particles in step S1 is 1-3:1.

[0011] Preferably, the solvent-resistant TPU particles are made of BASF C85A13.

[0012] Preferably, the polyester TPU particles have a hydroxyl value of 105 mgKOH / g to 110 mgKOH / g, a Shore hardness of 65A to 75A, a weight-average molecular weight of 80,000 to 90,000, and the soft segment uses polybutyl adipate with a molecular weight of 550 to 700, accounting for 52% to 56%; the polyether TPU particles have a hydroxyl value of 108 mgKOH / g to 112 mgKOH / g, a Shore hardness of 90A to 95A, a weight-average molecular weight of 100,000 to 110,000, and the soft segment uses PTMEG with a molecular weight of 1100 to 1200.

[0013] Preferably, the hot air temperature in steps S1 and S2 is 230° C. to 240° C., the hot air pressure is 0.15 MPa to 0.2 MPa, the receiving distance is 30 cm to 50 cm, and the hot air introduction angle is 50° to 60°.

[0014] Preferably, the collagen solution is a reaction solution obtained by reacting an alkaline aqueous solution of collagen with a cross-linking agent ECH at a temperature of 105° C. to 110° C. for 2-3 hours, and the collagen content is 15% to 20%.

[0015] Preferably, the spraying amount of the spunlace medium is 10L to 15L per square meter of the surface area of the meltblown inner layer.

[0016] Preferably, in the composite spinning of step S2, the volume ratio of the skin layer to the core layer is 1:1.5-2.5.

[0017] Preferably, the diameter of the single fiber of the meltblown inner layer in step S1 is 2 μm to 5 μm; the diameter of the single fiber of the meltblown surface layer in step S2 is 6 μm to 12 μm.

[0018] Preferably, the weight of the meltblown inner layer in step S1 is 5g / m 2 ~15g / m 2 The weight of the meltblown surface layer in step S2 is 15g / m 2 ~30g / m 2 .

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The TPU non-woven fabric of the present invention includes a meltblown inner layer and a meltblown surface layer. The single fiber of the meltblown surface layer is a skin-core composite structure, and the surface of the single fiber of the meltblown inner layer is a porous and rough structure. When the meltblown inner layer and the meltblown surface layer are composited, collagen liquid is used as the spunlace medium to graft collagen on the surface and porous parts of the single fiber of the meltblown inner layer and the surface of the single fiber of the meltblown surface layer. The natural antibacterial property and skin-friendly wetting power of the collagen itself improve the antibacterial and skin-friendly performance of the meltblown inner layer, and the antibacterial rate reaches more than 90%. At the same time, the skin layer of the meltblown surface layer adopts low-melting-point polyether TPU particles, which facilitates the firm consolidation of the single fiber of the meltblown surface layer and the porous and rough surface of the single fiber of the meltblown inner layer during the final hot air drying process. The hot air drying also plays the role of drying and removing free water in the collagen liquid and further consolidating the covalent bond grafting of collagen to the meltblown inner layer through the crosslinking agent ECH.

[0021] It should also be noted that the melt-blown inner layer of the present invention adopts solvent-resistant TPU particles and epoxy resin particles. The introduction of epoxy resin particles plays two roles: first, it reduces the melt flow temperature and melt viscosity of the solvent-resistant TPU particles, improves the spinnability of TPU and is conducive to the formation of TPU continuous phase, and facilitates the control of the single fiber size and mechanical performance after solvent reduction and removal of epoxy resin; second, a porous and rough surface is obtained by treating the single fiber in the melt-blown inner layer, and the carboxyl functional groups on the surface of the single fiber after plasma treatment are increased, thereby grafting more collagen, and also helps to improve the consolidation force between the melt-blown surface layer and the melt-blown inner layer, and the interlayer peel strength reaches more than 2.0N / 5cm.

[0022] The TPU nonwoven fabric of the present invention can be used for health-related purposes such as medical treatment / nursing, mainly disposable items, such as diapers, sanitary napkins, gauze, bandages, masks, gloves, bandages, etc., and can also be used in the fields of clothing fabrics and leather. DETAILED DESCRIPTION

[0023] Example 1

[0024] This embodiment provides a TPU nonwoven fabric production process, which specifically includes the following steps:

[0025] S1. Add solvent-resistant TPU particles C85A13 and epoxy resin particles in a mass ratio of 3:1 into a screw extruder and blend them into a melting spinning solution. The die temperature is 225°C, the hot air temperature is 240°C, the hot air pressure is 0.15MPa, the receiving distance is 40cm, and the hot air introduction angle is 60°. The melt-blowing method is used to lay the web on the web-forming machine to obtain a fiber web. The fiber web is then sent to the soaking tank for tension-free soaking in acetone organic solvent to dissolve and remove the epoxy resin. The soaking time is 1.5 hours and the soaking temperature is 45°C. Then, hot air drying, consolidation and bonding, and winding are performed to obtain a melt-blown inner layer. The hot air temperature is 130°C. The single fiber diameter is 3μm to 4μm and the single fiber surface has a porous and rough structure. The gram weight is 10.5g / m 2 .

[0026] S2, the melt-blown inner layer prepared in step S1 is fed to the feeding part of the melt-blown cloth production line, the melt-blown inner layer is unwound, plasma treated and then enters the web forming machine, the vacuum degree of the plasma chamber is 10 -5 ~10 -6 , the plasma power is 100W, the processing time is 8min; polyether TPU particles are used as the skin material and polyester TPU particles are used as the core material for skin-core composite spinning, the volume ratio of the skin layer to the core layer is 1:2, the hot air temperature is 230℃, the hot air pressure is 0.2MPa, the receiving distance is 30cm, the hot air introduction angle is 60°, and the meltblown surface layer is collected on the surface of the meltblown inner layer at the web forming machine. The single fiber diameter of the meltblown surface layer is 10μm and the gram weight is 18.5g / m 2 .

[0027] S3: The meltblown surface layer and meltblown inner layer laminated in step S2 were treated with collagen solution as the spunlace medium. The collagen solution was prepared by reacting an alkaline aqueous solution of collagen with a crosslinker, ECH, at 110°C for 2 hours. The collagen content was 15%. The spunlace medium was sprayed at a rate of 15 L per square meter of the meltblown inner layer surface area. Finally, the fabric was hot-air dried, trimmed, and rolled up at a hot-air temperature of 115°C. This TPU nonwoven fabric had an antibacterial rate against Staphylococcus aureus of 95.5% (GB / T20944.3-2008: oscillation method) and an interlayer peel strength (JIS K 6854-3: T-peel) of 2.2 N / 5 cm.

[0028] Example 2

[0029] This embodiment provides a TPU nonwoven fabric production process, which specifically includes the following steps:

[0030] S1. Add solvent-resistant TPU particles C85A13 and epoxy resin particles in a screw extruder at a mass ratio of 2:1 and blend them into a spinning solution. The die temperature is 225°C, the hot air temperature is 240°C, the hot air pressure is 0.15MPa, the receiving distance is 40cm, and the hot air introduction angle is 60°. The melt-blown method is used to lay the web on the web-forming machine to obtain a fiber web. The fiber web is then sent to the soaking tank for tension-free soaking in acetone organic solvent to dissolve and remove the epoxy resin. The soaking time is 1.5 hours and the soaking temperature is 45°C. Then, hot air drying, consolidation and bonding, and winding are performed to obtain a melt-blown inner layer. The hot air temperature is 135°C. The single fiber diameter is 2μm to 3μm, and the single fiber surface has a porous and rough structure. The gram weight is 8g / m 2 .

[0031] S2, the melt-blown inner layer prepared in step S1 is fed to the feeding part of the melt-blown cloth production line, the melt-blown inner layer is unwound, plasma treated and then enters the web forming machine, the vacuum degree of the plasma chamber is 10 -5 ~10-6 , the plasma power is 80W, the processing time is 10min; polyether TPU particles are used as the skin material and polyester TPU particles are used as the core material for skin-core composite spinning, the volume ratio of the skin layer to the core layer is 1:2.5, the hot air temperature is 230℃, the hot air pressure is 0.2MPa, the receiving distance is 30cm, the hot air introduction angle is 60°, and the meltblown surface layer is collected on the surface of the meltblown inner layer at the web forming machine. The single fiber diameter of the meltblown surface layer is 8μm and the gram weight is 25.5g / m 2 .

[0032] S3: The meltblown surface layer and meltblown inner layer laminated in step S2 were treated with collagen solution as the spunlace medium. The collagen solution was prepared by reacting an alkaline aqueous solution of collagen with a crosslinker, ECH, at 110°C for 2 hours. The collagen content was 20%. The spunlace medium was sprayed at a rate of 10 L per square meter of the meltblown inner layer surface area. Finally, the fabric was hot-air dried, trimmed, and rolled up at a hot-air temperature of 112°C. This TPU nonwoven fabric had an antibacterial rate against Staphylococcus aureus of 96.3% (GB / T20944.3-2008: oscillation method) and an interlayer peel strength (JIS K 6854-3: T-peel) of 2.1 N / 5 cm.

[0033] The polyester TPU particles in Examples 1 and 2 have a hydroxyl value of 105 mgKOH / g to 110 mgKOH / g, a Shore hardness of 65A to 75A, a weight-average molecular weight of 80,000 to 90,000, and a soft segment using polybutyl adipate with a molecular weight of 550 to 700, accounting for 52% to 56%, a melting range of 120°C to 130°C, and a melting range of 190°C to 200°C; the polyether TPU particles have a hydroxyl value of 108 mgKOH / g to 112 mgKOH / g, a Shore hardness of 90A to 95A, a weight-average molecular weight of 100,000 to 110,000, and a soft segment using PTMEG with a molecular weight of 1100 to 1200, with a melting range of 120°C to 130°C.

[0034] Comparative Example 1

[0035] The only difference between Comparative Example 1 and Example 1 is that the hydroentanglement medium treatment is not performed in step S3 but hot air drying is performed directly, and the antibacterial rate of the obtained TPU nonwoven fabric is significantly reduced.

[0036] Comparative Example 2

[0037] The only difference between Comparative Example 2 and Example 1 is that the spinning solution in step S1 does not contain epoxy resin particles but only solvent-resistant TPU particles, and no soaking treatment is performed. The antibacterial rate of the obtained TPU non-woven fabric is reduced by about 5.3% compared with Example 1, and the peel strength is reduced by 28.5%.

[0038] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which shall fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. TPU nonwoven production process, characterized in that, The specific steps include: S1. Solvent-resistant TPU particles and epoxy resin particles are melted together to form a spinning solution. After laying the web on a web-forming machine using a melt-blowing method, the web is tension-free soaked in acetone organic solvent to dissolve and remove the epoxy resin. The web is then hot-dried, consolidated, bonded, and rolled up to obtain a melt-blown inner layer. S2, the meltblown inner layer is unwound and plasma treated before entering the web forming machine, where polyether TPU particles are used as the skin material and polyester TPU particles are used as the core material for composite spinning. The meltblown inner layer surface is collected at the web forming machine to obtain the meltblown surface layer; S3, using collagen liquid as the spunlace medium to process the meltblown surface layer and meltblown inner layer laminated in step S2, and finally drying with hot air, trimming and rolling; The collagen solution is a reaction solution obtained by reacting an alkaline aqueous solution of collagen with a cross-linking agent ECH at a temperature of 105° C. to 110° C. for 2-3 hours, and the collagen content is 15% to 20%.

2. The TPU nonwoven fabric production process according to claim 1, characterized in that: The mass ratio of the solvent-resistant TPU particles to the epoxy resin particles in step S1 is 1-3:

1.

3. The TPU nonwoven fabric production process according to claim 1, characterized in that: The solvent-resistant TPU particles are BASF C85A13.

4. The TPU nonwoven fabric production process according to claim 1, characterized in that: The polyester TPU particles have a hydroxyl value of 105 mgKOH / g to 110 mgKOH / g, a Shore hardness of 65A to 75A, a weight-average molecular weight of 80,000 to 90,000, and the soft segment uses polybutyl adipate with a molecular weight of 550 to 700, accounting for 52% to 56%; the polyether TPU particles have a hydroxyl value of 108 mgKOH / g to 112 mgKOH / g, a Shore hardness of 90A to 95A, a weight-average molecular weight of 100,000 to 110,000, and the soft segment uses PTMEG with a molecular weight of 1100 to 1200.

5. The TPU nonwoven fabric production process according to claim 1, characterized in that: The hot air temperature in steps S1 and S2 is 230° C. to 240° C., the hot air pressure is 0.15 MPa to 0.2 MPa, the receiving distance is 30 cm to 50 cm, and the hot air introduction angle is 50° to 60°.

6. The TPU nonwoven fabric production process according to claim 1, characterized in that: The spraying amount of the spunlace medium is 10L to 15L per square meter of the surface area of the meltblown inner layer.

7. The TPU nonwoven fabric production process according to claim 1, characterized in that: In the composite spinning of step S2, the volume ratio of the skin layer to the core layer is 1:1.5-2.

5.

8. The TPU nonwoven fabric production process according to claim 1, characterized in that: The diameter of the single fiber of the meltblown inner layer in step S1 is 2 μm to 5 μm; the diameter of the single fiber of the meltblown surface layer in step S2 is 6 μm to 12 μm.

9. The TPU nonwoven fabric production process according to claim 1, characterized in that: The weight of the meltblown inner layer in step S1 is 5g / m 2 ~15g / m 2 The weight of the meltblown surface layer in step S2 is 15g / m 2 ~30g / m 2 .