Photocuring TPU (thermoplastic polyurethane) waterproof and moisture-permeable film and preparation method thereof

Abstract

The invention relates to the technical field of polymer film materials, in particular to a light-cured TPU waterproof and moisture-permeable film and a preparation method thereof.The preparation method comprises the following steps that polyether polyol, polyurethane acrylic resin and auxiliaries are heated and mixed to be uniform, then the mixture and MDI are subjected to extrusion granulation, and light-cured moisture-permeable TPU particles are obtained; pE particles and light-cured moisture-permeable TPU particles are subjected to blow molding through an extruder A and an extruder B to form a TPU / PE composite film, the TPU / PE composite film is cooled and then subjected to curing and crosslinking through an ultraviolet emitting device, then trimming and rolling are conducted, and the light-cured TPU waterproof moisture-permeable film is obtained. During low-temperature TPU processing, the stability of the raw materials can be kept, material degradation or side reaction caused by high temperature is reduced, the operability in the film processing process is remarkably improved, in addition, the prepared light-cured TPU waterproof and moisture-permeable film can keep stable physical and chemical properties at higher temperature, and the light-cured TPU waterproof and moisture-permeable film has the advantages of being good in waterproof and moisture-permeable performance and good in waterproof and moisture-permeable performance. And deformation, softening or damage cannot easily occur.

Description

Technical Field

[0001] The invention relates to the technical field of polymer film materials, and in particular to a light-cured TPU waterproof and moisture-permeable film and a preparation method thereof. Background Art

[0002] Most jacket fabrics use PU film, PTFE film and other waterproof and breathable films as waterproof layers, which are bonded to the surface fabric. PU glue, the raw material of PU film, uses a large amount of solvents such as DMF, acetone, toluene, etc. during synthesis. When the PU film is produced and dried at the back end, a large amount of organic solvents are produced, which causes harm to the operator's body and mind and the environment. PTFE membrane is difficult to degrade due to its material stability, and large-scale use can easily cause white pollution. The new environmentally friendly waterproof and breathable membrane uses TPU as the raw material and is produced using blow molding or cast film technology, avoiding the problem of using solvents in the back-end film processing and achieving environmental protection effects.

[0003] However, the blow molding or cast film process requires the raw materials to be thermoplastic, heated and melted by an extruder, and extruded through a die. The thickness of such films is generally around 0.015mm-0.025mm, and has the following disadvantages: 1. The raw material is thermoplastic polyurethane, which melts when heated. During the production of jackets, hot melt tape is required to fit the seam stop and hot melt adhesive film is required to bond, which will damage the TPU film; 2. If the softening or rheological temperature of TPU is increased, it is easy to cause problems such as poor plasticization and material accumulation during the production of the film at the back end, which is not conducive to production and processing; 3. Scratches are prone to occur during fabric bonding, jacket processing, and daily wear of finished garments. The TPU film is thin and has low strength, which can easily cause damage to the TPU film.

[0004] Therefore, it is very necessary to design a TPU film with good temperature resistance and strength to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to provide a light-cured TPU waterproof and breathable film and a preparation method thereof, which improves the operability of film processing and avoids the problem of material accumulation during long-term processing, and the prepared light-cured TPU waterproof and breathable film has excellent temperature resistance and strength.

[0006] The objective of the present invention is achieved through the following technical solutions:

[0007] The present invention provides a method for preparing a light-cured TPU waterproof and breathable film, comprising the following steps:

[0008] (1) The polyether polyol, polyurethane acrylic resin and additives are heated and mixed evenly, and then pumped into a polyurethane extruder with MDI in proportion through a metering pump, and the temperature is set at 190° C. for extrusion and granulation to obtain light-cured moisture-permeable TPU particles;

[0009] (2) PE particles and light-cured breathable TPU particles are added to extruder A and extruder B respectively, heated and melted and extruded to the inner layer and outer layer of the die head, blown into a TPU / PE composite film, cooled and passed through an ultraviolet emitting device for curing and cross-linking, and then trimmed and rolled to obtain a light-cured TPU waterproof and breathable film.

[0010] Furthermore, in step (1), the auxiliary agent includes a chain extender, a photoinitiator, an anti-hydrolysis agent, an antioxidant, a light stabilizer, an ultraviolet absorber and a lubricant.

[0011] Among them, the above-mentioned anti-hydrolysis agent is polycarbodiimide, which can improve the hydrolysis resistance of TPU waterproof and breathable film; the antioxidant improves the thermal degradation performance of TPU particles during high-temperature melt extrusion; the light stabilizer and ultraviolet absorber can improve the UV yellowing resistance of TPU hot melt adhesive.

[0012] Furthermore, in step (1), the polyether polyol is present in an amount of 20-50 parts, the polyurethane acrylic resin is present in an amount of 5-10 parts, and the MDI is present in an amount of 30-50 parts.

[0013] Furthermore, the proportions of the auxiliary agents are 10-20 parts of chain extender, 0-0.5 parts of photoinitiator, 0-1 parts of anti-hydrolysis agent, 0-1 parts of antioxidant, 0-1 parts of light stabilizer, and 0-10 parts of lubricant.

[0014] Furthermore, in step (1), the softening point of the finally obtained light-cured moisture-permeable TPU particles is 180° C.-190° C., and the melt index is 30-60 g / 10 min at 200° C. and 2160 g.

[0015] Furthermore, in step (1), the heating is heating to 100°C-110°C.

[0016] Furthermore, in step (2), the thickness of the TPU / PE composite film is 0.025 mm-0.04 mm, wherein the thickness of the TPU film is 0.015-0.025 mm, and the light-cured moisture-permeable TPU particle component in the TPU / PE composite film is on the outside.

[0017] The present invention also provides a light-cured TPU waterproof and breathable film, and the light-cured TPU waterproof and breathable film is prepared by the preparation method.

[0018] The beneficial effects of the present invention are:

[0019] In the preparation method of the present invention, PE particles and light-cured breathable TPU particles are added to extruder A and extruder B respectively, heated and melted and extruded to the inner layer and outer layer of the die head, and blown into a TPU / PE composite film, and the heating temperature is controlled within a relatively low range of 170°C-190°C. This low-temperature treatment not only helps to maintain the stability of the raw materials and reduce material degradation or side reactions caused by high temperature, but also significantly improves the operability during film processing. Under low temperature conditions, the material has moderate fluidity and is easy to be evenly dispersed and mixed in the equipment, thereby avoiding problems such as material accumulation, blockage or material pyrolysis that may occur during long-term processing. This not only improves production efficiency, but also ensures the consistency and stability of product quality.

[0020] At the same time, the present invention is cured and cross-linked by an ultraviolet emitting device, so that the light-cured moisture-permeable TPU particle components in the TPU / PE composite film undergo a cross-linking reaction, forming a more compact and stable network structure. This cross-linked structure not only gives the film excellent waterproof and moisture-permeable properties, but also significantly improves its temperature resistance. The cross-linked film can maintain stable physical and chemical properties at higher temperatures and is not prone to deformation, softening or damage. At the same time, the cross-linked structure also enhances the mechanical strength of the film, making it have better tensile, tear and impact resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 It is a process flow chart of the method for preparing the light-cured TPU waterproof and breathable membrane in the present invention;

[0023] Figure 2 The specific structure diagram of the light-cured TPU waterproof and breathable membrane prepared in the present invention. DETAILED DESCRIPTION

[0024] The embodiments of the present invention are described in detail below, and the embodiments are intended to explain the present invention and should not be construed as limiting the present invention. If specific techniques or conditions are not specified in the embodiments, they are carried out according to the techniques or conditions described in the literature in this area or according to the product specifications. If the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be obtained commercially.

[0025] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific implementation methods of the present invention are now described.

[0026] The method for preparing the light-cured TPU waterproof and breathable membrane of the present invention specifically comprises the following steps:

[0027] (1) Polyether polyol, polyurethane acrylic resin and additives are heated (100°C-110°C) and mixed evenly, and then pumped into a polyurethane extruder with MDI in proportion through a metering pump, extruded and granulated, and the extruder temperature is set at 190°C to obtain light-cured moisture-permeable TPU particles; wherein the additives include chain extenders, photoinitiators, anti-hydrolysis agents, antioxidants, light stabilizers, ultraviolet absorbers and lubricants; the proportions of each raw material in the light-cured moisture-permeable TPU particles are: 20-50 parts of polyether polyol, and 20-50 parts of MDI. 30-50 parts, chain extender 10-20 parts, polyurethane acrylic resin 5-10 parts, photoinitiator 0-0.5 parts, anti-hydrolysis agent 0-1 parts, antioxidant 0-1 parts, light stabilizer 0-1 parts, ultraviolet absorber 0-1 parts, lubricant 0-10 parts; the softening point of the above-mentioned light-cured waterproof and breathable TPU particles is 180℃-190℃ (ring and ball softening point), and the melt index is 30-60g / 10min (200℃, 2160g);

[0028] (2) PE particles and dried light-cured breathable TPU particles are added to extruder A and extruder B respectively, heated and melted and extruded to the inner and outer layers of the die head, blown into a thickness of 0.025 mm-0.04 mm, wherein the thickness of the TPU film is 0.015-0.025 mm, and after cooling, passed through an ultraviolet emitting device, irradiated with ultraviolet light for curing and cross-linking, and then trimmed and rolled to obtain a light-cured TPU waterproof and breathable film; wherein the above-mentioned light-cured waterproof and breathable TPU particles need to be protected from light before synthesis and back-end processing into a film to prevent the particles from reacting prematurely under light conditions.

[0029] The process flow chart of the above specific preparation method is shown in Figure 1 The specific structure of the finally obtained light-cured TPU waterproof and breathable membrane is shown in Figure 2 .

[0030] Example 1

[0031] The preparation method of the light-cured TPU waterproof and breathable film in this embodiment includes the following steps:

[0032] (1) Select 45 parts of polyether polyol, 45 parts of MDI, 10 parts of chain extender, 8 parts of polyurethane acrylic resin, 0.4 parts of photoinitiator, 0.5 parts of anti-hydrolysis agent, 0.5 parts of antioxidant, 0.5 parts of light stabilizer and 5 parts of lubricant for use.

[0033] (2) The polyether polyol, polyurethane acrylic resin and the above-mentioned additives are heated at 105° C. in proportion, mixed evenly and then pumped into a polyurethane extruder through a metering pump with MDI in the above-mentioned proportion, and the temperature is set at 190° C. for extrusion granulation to obtain light-cured moisture-permeable TPU particles.

[0034] (3) PE particles and the above-mentioned light-cured waterproof and breathable TPU particles dried at 100° C. for 8 h were respectively added to the extruder A and extruder B of the TPU film blowing machine, and the film was produced according to the specific process shown in Table 1, wherein the light-cured and breathable TPU particles were protected from light throughout the process, and finally a light-cured TPU waterproof and breathable film was obtained.

[0035] Table 1 Preparation process of light-cured TPU waterproof and breathable film

[0036]

[0037] The properties of the final photocured TPU waterproof and breathable film are shown in Table 2.

[0038] Table 2 Performance of the light-cured TPU waterproof and breathable film obtained by the preparation method in Example 1 of the present invention

[0039] index Before irradiation After UV exposure Melt index g / 10min 51.2(200℃，2160g) 1.6(210℃，2160g) Softening point℃(Ring and ball method) 186℃ 209℃

[0040] Table 3 Performance of the light-cured TPU waterproof and breathable film obtained by the preparation method in Example 1 of the present invention

[0041] index Before irradiation After UV exposure Breaking strength 16.5MPa 28.4MPa Elongation at break 620％ 560％

[0042] The above Tables 2 and 3 test the temperature resistance and mechanical properties. The soft point of the film is 186°C, which rises to 209°C after ultraviolet light exposure. The melt index also drops from 51.2g / 10min (200°C) to 1.6g / 10min (210°C). The two temperature resistance indicators are significantly improved. The water stop strip pressed on the fabric in the later stage will not rupture due to the heat of the TPU film. The breaking strength index is increased from 16.5MPa to 28.4MPa. The film strength is significantly improved, so the TPU film is not easily damaged during the fabric bonding, garment processing and wearing process, thereby increasing the service life of the garment.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be covered by the scope of the claims of the present invention.

Claims

1. A method for preparing a light-cured TPU waterproof and breathable membrane, characterized in that: The following steps are involved: (1) The polyether polyol, polyurethane acrylic resin and additives are heated and mixed evenly, and then pumped into a polyurethane extruder with MDI in proportion through a metering pump, and the temperature is set at 190° C. for extrusion and granulation to obtain light-cured moisture-permeable TPU particles; (2) PE particles and light-cured breathable TPU particles are added to extruder A and extruder B respectively, heated and melted and extruded to the inner layer and outer layer of the die head, blown into a TPU / PE composite film, cooled and passed through an ultraviolet emitting device for curing and cross-linking, and then trimmed and rolled to obtain a light-cured TPU waterproof and breathable film.

2. The method for preparing the light-cured TPU waterproof and breathable membrane according to claim 1, characterized in that: In step (1), the auxiliary agents include chain extenders, photoinitiators, anti-hydrolysis agents, antioxidants, light stabilizers, and lubricants.

3. The method for preparing the light-cured TPU waterproof and breathable membrane according to claim 1, characterized in that: In step (1), the polyether polyol is present in an amount of 20-50 parts, the polyurethane acrylic resin is present in an amount of 5-10 parts, and the MDI is present in an amount of 30-50 parts.

4. The method for preparing the light-cured TPU waterproof and breathable membrane according to claim 2, characterized in that: The proportions of the auxiliary agents are: 10-20 parts of chain extender, 0-0.5 parts of photoinitiator, 0-1 parts of anti-hydrolysis agent, 0-1 parts of antioxidant, 0-1 parts of light stabilizer, and 0-10 parts of lubricant.

5. The method for preparing the light-cured TPU waterproof and breathable membrane according to claim 1, characterized in that: In step (1), the softening point of the finally obtained light-cured moisture-permeable TPU particles is 180° C.-190° C., and the melt index is 30-60 g / 10 min at 200° C. and 2160 g.

6. The method for preparing the light-cured TPU waterproof and breathable particles according to claim 1, characterized in that: In step (1), the heating is heating to 100°C-110°C.

7. The method for preparing the light-cured TPU waterproof and breathable membrane according to claim 1, characterized in that: In step (2), the thickness of the TPU / PE composite film is 0.025 mm-0.04 mm, wherein the thickness of the TPU film is 0.015-0.025 mm, and the light-cured moisture-permeable TPU particle component in the TPU / PE composite film is on the outside.

8. A light-cured TPU waterproof and breathable membrane, characterized in that: The light-cured TPU waterproof and breathable membrane is prepared by the preparation method described in any one of claims 1 to 7.

Images