Nylon moisture-permeable film and preparation method thereof

Abstract

The invention discloses a nylon moisture-permeable film and a preparation method thereof, and belongs to the technical field of nylon films. The preparation method of the film comprises the following steps: (1) mixing and granulating the glass fiber, the multi-block polyamide-polyurethane copolymer and the compatilizer to prepare glass fiber master batch; (2) melting and extruding the glass fiber master batch and the mixed additive to obtain an additive master batch; the mixed additive is prepared from polysiloxane, an ethylene-acrylic acid zinc ion copolymer, oleamide, silicon dioxide, phosphite ester and lupeol; and (3) drying the multi-block polyamide-polyurethane copolymer and the assistant master batch, adding the dried multi-block polyamide-polyurethane copolymer and assistant master batch into a film blowing machine, stirring, melting and extruding, cooling and blowing extruded molten plastic to form film bubbles, extruding the film bubbles through a herringbone clamping plate to convert the film bubbles into a thin film, and cooling, curing, stretching, trimming and rolling to obtain the nylon moisture-permeable film. The obtained film has the characteristics of high elongation at break, high moisture permeability, low rebound rate and the like, and the preparation process is simple, high in production efficiency and easy to implement.

Description

Technical Field

[0001] The present invention relates to the technical field of nylon films, and more specifically, to a nylon moisture-permeable film and a preparation method thereof. Background Art

[0002] Among the homogeneous films with moisture permeability on the market, such as TPU moisture-permeable films, TPEE moisture-permeable films, PU moisture-permeable films, PTFE moisture-permeable films, etc., none of them have the characteristics of high moisture permeability and high mechanical properties while being thin and light.

[0003] Nylon is a mature non-toxic, environmentally friendly and recyclable material. The disadvantage is that pure nylon film has too high hygroscopicity, too strong stickiness to the die roller, is not easy to form a film, and the industrial production is difficult. Adding additives helps to solve the problem of difficult film formation, but the addition of additives will reduce the overall mechanical properties and moisture permeability of the film. At present, the moisture permeability of nylon films on the market can only reach about 2500 g / m 2 *24h or so, with a thickness of 12 - 25 microns, which cannot meet the requirements of easy film formation, being thinner, lighter, having a high moisture permeability and high mechanical properties. Summary of the Invention

[0004] The purpose of the present invention is to overcome the above-mentioned deficiencies of the prior art, and provide a nylon moisture-permeable film and a preparation method thereof. This film is mainly formed by mixing a multi-block polyamide-polyurethane copolymer with a certain proportion of additive masterbatch and then using a blown film device according to processes such as drying - melting - extruding - stretching. This film has characteristics such as high elongation at break, high moisture permeability, and low resilience rate. Its preparation process is simple and mature, with high production efficiency, easy to implement, and convenient for industrial development and application.

[0005] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0006] A preparation method of a nylon moisture-permeable film, comprising the following steps:

[0007] (1) Prepare a glass fiber masterbatch: Mix glass fiber, a multi-block polyamide-polyurethane copolymer, and a compatibilizer and granulate to obtain a glass fiber masterbatch;

[0008] (2) Prepare an additive masterbatch: Mix and melt-extrude the glass fiber masterbatch with a mixed additive to obtain an additive masterbatch; The mixed additive is composed of polysiloxane, ethylene zinc acrylate ion copolymer, oleic acid amide, silicon dioxide, phosphite, and lupetol.

[0009] (3) Preparation of nylon moisture-permeable membrane: Add the multi-block polyamide-polyurethane copolymer and the masterbatch of additives into the masterbatch dryer according to a certain proportion for mixing, stirring and drying. After drying, add them to the blown film machine for stirring, melting and extruding into a continuous molten plastic strip. The extruded molten plastic forms a film bubble through the cooling and inflation of the air ring. The film bubble is transformed into a film by squeezing with the herringbone breaker plate, and after cooling and solidification, stretching, trimming and winding, the nylon moisture-permeable membrane is obtained.

[0010] The present invention is further configured such that the multi-block polyamide-polyurethane copolymer described in steps (1) and (3) is a block copolymer of one of PA6, PA66, PA56 and polyurethane, and the polyurethane content is 25-40%.

[0011] The present invention is further configured such that in step (1), the mass ratio of glass fiber, compatibilizer, and multi-block polyamide-polyurethane copolymer is 4:(0.5-1):(5.5-8).

[0012] The present invention is further configured such that in step (1), the compatibilizer is a composition formed by combining maleic anhydride grafted compatibilizer and anti-glass fiber exposure agent in a mass ratio of 4:1.

[0013] The present invention is further configured such that in step (2), the mass ratio of the glass fiber masterbatch to the mixed additives is (8-9):1.

[0014] The present invention is further configured such that in step (2), the mass ratio of polysiloxane, ethylene zinc acrylate ion copolymer, oleic acid amide, silica, phosphite, and lupetol in the mixed additives is 2:0.5:1:4:1.5:1.

[0015] The present invention is further configured such that in step (3), the mass ratio of the multi-block polyamide-polyurethane copolymer to the masterbatch of additives is (95-85):(5-15).

[0016] The present invention is further configured such that in step (3), the drying temperature is 90-95 °C and the drying time is 18-20 h.

[0017] The present invention is further configured such that in step (3), the speed of the blown film machine is 10-15 m / min, the extrusion temperature is 180-215 °C, the extrusion pressure is 3-15 kg, the roll tension is 6-9 kg, and the blow-up ratio is 1:2-4.

[0018] A nylon moisture-permeable membrane, which is prepared according to the above method; the thickness of the membrane is 4-5 microns, the gram weight is 5-6.3 g / m 2 , the moisture permeability is 7950-8190 g / m 2 *24 h, the breaking elongation rate is 285-312%, and the resilience rate is 8-13%.

[0019] In summary, the present invention has the following beneficial effects:

[0020] Using a multi-block nylon polyurethane copolymer as a raw material, and then melt-extruding it with a special formula to obtain a nylon moisture-permeable film (wherein, polysiloxane, ethylene zinc acrylate copolymer, oleic acid amide, and silica are used as slip agents, which can increase the material fluidity, reduce the viscosity of the nylon material after film formation, and reduce the production difficulty; the combination of phosphite and lupetol is used as an antioxidant to improve the yellowing resistance and antioxidant property of the film and extend the service life of the material; adding glass fiber can improve the mechanical properties, dimensional stability, aging resistance, and fatigue strength of the nylon moisture-permeable film). Not only do all mechanical properties meet the requirements (the breaking elongation rate is 285-312%, and the resilience rate is 8-13%), but also the film thickness can be reduced to 4-5 microns, and the moisture permeability reaches 7950-8190 g / m 2 *24h, ensuring a high moisture permeability of the nylon film in a thin and light size, and solving the problem of difficult nylon production. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is the infrared reflectance recovery peak data of the nylon moisture-permeable film prepared in Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0022] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0023] The preparation method of the nylon moisture-permeable film of the present invention includes the following steps:

[0024] (1) Prepare a glass fiber masterbatch: Mix glass fiber, multi-block polyamide-polyurethane copolymer, and compatibilizer and granulate to make a glass fiber masterbatch. Among them, the mass ratio of glass fiber, compatibilizer, and multi-block polyamide-polyurethane copolymer is 4:(0.5-1):(5.5-8), the compatibilizer is a composition of maleic anhydride grafted compatibilizer and anti-glass fiber exposure agent combined by a mass ratio of 4:1, and the multi-block polyamide-polyurethane copolymer is a block copolymer of one of PA6, PA66, and PA56 and polyurethane, wherein the polyurethane content is 25-40%.

[0025] (2) Preparation of the auxiliary masterbatch: Mix and melt-extrude the glass fiber masterbatch and the mixed auxiliary agents in a mass ratio of (8 - 9):1 to obtain the auxiliary masterbatch; the mixed auxiliary agents are composed of polydimethylsiloxane, ethylene zinc acrylate ion copolymer, oleic acid amide, silica, phosphite, and lupetol in a mass ratio of 2:0.5:1:4:1.5:1.

[0026] (3) Preparation of the nylon moisture-permeable film: Add the multi-block polyamide-polyurethane copolymer (a block copolymer of one of PA6, PA66, PA56 and polyurethane, with the polyurethane content being 25 - 40%) and the auxiliary masterbatch into the masterbatch dryer in a mass ratio of (95 - 85):(5 - 15) for mixing, stirring and drying (the drying temperature is 90 - 95°C, and the drying time is 18 - 20 h). After drying, add them to the blown film machine for stirring, melting and extruding into a continuous molten plastic strip. The extruded molten plastic forms a film bubble through the cooling and inflation of the air ring, and is transformed into a film by squeezing the film bubble with the chevron plate. Control the speed of the blown film machine at 10 - 15 m / min, the extrusion temperature at 180 - 215°C, the extrusion pressure at 3 - 15 kg, the roll tension at 6 - 9 kg, and the blow-up ratio at 1:2 - 4; after cooling and solidification, stretching, trimming and winding treatments, a nylon moisture-permeable film with a thickness of 4 - 5 microns and a grammage of 5 - 6.3 g / m 2 is obtained.

[0027] The specific embodiments are as follows:

[0028] Example 1: Preparation of the glass fiber masterbatch and the auxiliary masterbatch

[0029] (1) Place the multi-block polyamide-polyurethane copolymer (a block copolymer of PA6 and polyurethane, with the polyurethane content being 25%) in an oven at 90°C for drying for 18 hours. Mix the multi-block polyamide-polyurethane copolymer with glass fiber, anti-glass fiber exposure agent, and maleic anhydride compatibilizer in a mass ratio of 30:16:0.8:3.2, and melt and stir-extrude at 200°C to granulate, obtaining the glass fiber masterbatch.

[0030] (2) Take the glass fiber masterbatch and place it in an oven at 90°C for drying for 12 hours. Mix the glass fiber masterbatch with polydimethylsiloxane, ethylene zinc acrylate ion copolymer, oleic acid amide, silica, lupetol, and phosphite in a ratio of 36:0.8:0.2:0.4:1.6:0.4:0.6, and melt and stir-extrude at 200°C to granulate, obtaining the auxiliary masterbatch.

[0031] Example 2

[0032] The multi-block polyamide-polyurethane copolymer and the additive masterbatch are put into a masterbatch dryer according to a mass ratio of 19:1, mixed, stirred and dried at 90°C for 18 hours. After drying, they are added to a blown film machine for stirring, melting and extruding into a continuous molten plastic strip. The extruded molten plastic forms a film bubble through the cooling and inflation of the air ring, and the film bubble is transformed into a film by squeezing with a chevron plate. The speed of the blown film machine is controlled at 15 m / min, the extrusion temperature is 210°C, the extrusion pressure is 5 kg, the roll tension is 8 kg, and the blow-up ratio is 1:4. After cooling, curing, stretching, trimming and winding treatments, a nylon moisture-permeable film is obtained.

[0033] The performance of the nylon moisture-permeable film prepared in this example is detected (the film thickness is 5.12 microns, and the grammage is 6.22 g / m 2 , and 5 groups of specimens are measured). According to the national standard document GB / T2679.2-2015, using the upright cup moisture permeability measurement method, its average moisture permeability is 8050 g / m 2 *24h. According to the national standard document GB / T 1040.3-2006, using a material tensile machine to test its average breaking elongation rate is 312%; according to the American standard ASTM D638, using a material tensile machine to test its average resilience rate is 13%. See Tables 1 - 3 for details.

[0034] According to Figure 1 the infrared reflectance data of the nylon moisture-permeable film (prepared in Example 2), the wavelength peaks appearing around 1100 indicate the C-O stretching vibration of ester compounds, the wavelength peaks appearing around 1500 and 1650 indicate the presence of carbonyl functional groups, the wavelength peaks appearing around 2900 and 3000 indicate the presence of hydroxyl and amino functional groups, and the wavelength peak appearing around 3400 indicates the presence of hydroxyl functional groups. Through analysis, it can be seen that the nylon moisture-permeable film mainly contains polyamide and polyurethane, and the additives contain silicon, zinc, amide, ester, etc., all of which are in line with the trend of the infrared wavelength peak diagram.

[0035] Example 3

[0036] The multi-block polyamide-polyurethane copolymer and the additive masterbatch are put into a masterbatch dryer according to a mass ratio of 17:3, mixed, stirred and dried at 90°C for 18 hours. After drying, they are added to a blown film machine for stirring, melting and extruding into a continuous molten plastic strip. The extruded molten plastic forms a film bubble through the cooling and inflation of the air ring, and the film bubble is transformed into a film by squeezing with a chevron plate. The speed of the blown film machine is controlled at 15 m / min, the extrusion temperature is 210°C, the extrusion pressure is 5 kg, the roll tension is 8 kg, and the blow-up ratio is 1:4. After cooling, curing, stretching, trimming and winding treatments, a nylon moisture-permeable film is obtained.

[0037] The performance of the nylon moisture-permeable film prepared in this example is detected (the film thickness is 4.75 microns, and the grammage is 5.13 g / m2 , five groups of specimens were measured). According to the national standard document GB / T2679.2-2015, using the positive cup moisture permeability measurement method, its average moisture permeability is 7956 g / m 2 *24h. According to the national standard document GB / T 1040.3-2006, using a material tensile machine to test its average breaking elongation rate is 288%; according to the American standard ASTM D638, using a material tensile machine to test its average resilience rate is 9%. See Tables 1 - 3 for details.

[0038] Example 4

[0039] The multi-block polyamide-polyurethane copolymer and the additive masterbatch were put into a masterbatch dryer according to a mass ratio of 18:2, mixed, stirred and dried at 90 °C for 18 hours. After drying, they were added to a blown film machine for stirring, melting and extruding into a continuous molten plastic strip. The extruded molten plastic was formed into a film bubble through the cooling and inflation of the air ring, and the film bubble was transformed into a film by squeezing with a herringbone clamp. The speed of the blown film machine was controlled at 15 m / min, the extrusion temperature was 210 °C, the extrusion pressure was 5 kg, the roll tension was 8 kg, and the blow-up ratio was 1:4; after cooling and curing, stretching, trimming and winding treatments, a nylon moisture permeable film was obtained.

[0040] Detect the performance of the nylon moisture permeable film prepared in this example (the film thickness is 4.98 microns, and the grammage is 5.38 g / m 2 , five groups of specimens were measured). According to the national standard document GB / T2679.2-2015, using the positive cup moisture permeability measurement method, its average moisture permeability is 8188 g / m 2 *24h. According to the national standard document GB / T 1040.3-2006, using a material tensile machine to test its average breaking elongation rate is 297%; according to the American standard ASTM D638, using a material tensile machine to test its average resilience rate is 9%. See Tables 1 - 3 for details.

[0041] Comparative Example 1

[0042] A commercially available 10-micron PA moisture permeable film was purchased as Comparative Example 1. Detecting the performance of this moisture permeable film (five groups of specimens were measured) shows that: according to the national standard document GB / T2679.2-2015, using the positive cup moisture permeability measurement method, its average moisture permeability is 1095 g / m 2 *24h. According to the national standard document GB / T 1040.3-2006, using a material tensile machine to test its average breaking elongation rate is 298%; according to the American standard ASTM D638, using a material tensile machine to test its average resilience rate is 16%. See Tables 1 - 3 for details.

[0043] Comparative Example 2

[0044] The commercially available 10-micron TPU moisture-permeable film was purchased as Comparative Example 2. Detecting the performance of this moisture-permeable film (measuring 5 groups of specimens), it can be known that: according to the national standard document GB / T 2679.2-2015, using the upright cup moisture permeability measurement method, its average moisture permeability is 5587 g / m 2 *24h. According to the national standard document GB / T 1040.3-2006, using a material tensile machine to test its average breaking elongation rate is 200%; according to the American standard ASTM D638, using a material tensile machine to test its average resilience rate is 9%. See Tables 1-3 for details.

[0045] Comparative Example 3

[0046] The commercially available 10-micron TPEE moisture-permeable film was purchased as Comparative Example 3. Detecting the performance of this moisture-permeable film (measuring 5 groups of specimens), it can be known that: according to the national standard document GB / T 2679.2-2015, using the upright cup moisture permeability measurement method, its average moisture permeability is 4660 g / m 2 *24h. According to the national standard document GB / T 1040.3-2006, using a material tensile machine to test its average breaking elongation rate is 176%; according to the American standard ASTM D638, using a material tensile machine to test its average resilience rate is 19%. See Tables 1-3 for details.

[0047] Table 1

[0048]

[0049] Table 2

[0050]

[0051] Table 3

[0052]

[0053]

[0054] From the data obtained in Examples 2-4, it can be seen that when the proportion of the nylon moisture-permeable film is appropriately changed within the mixing ratio range, there are no significant differences in the moisture permeability, tensile fracture rate, and resilience rate; from the data obtained in Examples 2-4 and Comparative Example 1, it can be seen that the gap in moisture permeability between the ordinary nylon film and the nylon moisture-permeable film of the present invention is too large, and the gap in the other two mechanical property data is relatively small, indicating that the nylon moisture-permeable film of the present invention not only improves the moisture permeability performance, but also has mechanical properties not inferior to those of thicker ordinary nylon films when it is only 5 microns thick. From the data obtained in Examples 2-4 and Comparative Examples 2 and 3, it can be seen that compared with the high-moisture-permeable homogeneous films on the market, the nylon moisture-permeable film leads far ahead in terms of moisture permeability performance and tensile fracture rate, and its resilience rate is basically the same as that of thicker TPU films.

[0055] Comparative Example 4

[0056] The auxiliary masterbatch was prepared according to Example 1 without adding glass fiber, and then the nylon film was prepared according to Example 2. After testing, the fatigue resistance strength of the nylon film in Example 2 was 2.5 times that of this comparative example.

[0057] Comparative Example 5

[0058] The auxiliary masterbatch was prepared according to Example 1 without adding lupenol, and then the nylon film was prepared according to Example 2. After testing, the yellowing indices of the nylon films in Example 2 and Comparative Example 5 were 1.21 and 3.8 respectively, and the average elongation at break of the nylon film in Comparative Example 5 was 40.6% lower than that in Example 2.

[0059] In the above examples and comparative examples:

[0060] For the test of water vapor transmission rate, the weighing method under Condition 2 in the national standard document GB / T 2679.2-2015 was referred to: the temperature was 38±1°C, the relative humidity was 90±2%, and the test was carried out on a Jinan Labthink water vapor transmission tester.

[0061] For the tensile elongation at break, Type 5 specimens in the national standard document GB / T 1040.3-2006 were referred to. The conditions were: the width of the narrow parallel part was 10 mm, the width of the end part was 20 mm, the thickness was less than 1 mm, the gauge length was 50 mm, the length of the narrow parallel part was 60 mm, the initial distance between the clamps was 115 mm, the total length was 150 mm, and it was stretched until the film broke; the test was carried out on a Jinan Labthink tensile testing machine.

[0062] For the resilience rate test, the American standard ASTM D638 was referred to. Using a Jinan Labthink tensile testing machine, the conditions were: the width of the narrow parallel part was 10 mm, the width of the end part was 20 mm, the thickness was less than 1 mm, the gauge length was 50 mm, the length of the narrow parallel part was 60 mm, the initial distance between the clamps was 115 mm, the total length was 150 mm, the gauge length of 50 mm was stretched to a calibration strain of 100 mm, the load was released after maintaining for 60 seconds, and the residual strain was measured after 120 seconds to obtain the resilience rate.

[0063] The above are only the preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions falling within the concept of the present invention belong to the protection scope of the present invention. It should be noted that for those of ordinary skill in the art in this technical field, several improvements and refinements made without departing from the principle of the present invention should also be regarded as within the protection scope of the present invention.

Claims

1. A method for preparing a nylon moisture-permeable membrane, characterized in that, It includes the following steps: (1) Prepare glass fiber masterbatch: Mix glass fiber, multi-block polyamide-polyurethane copolymer, and compatibilizer and granulate them to obtain glass fiber masterbatch; (2) Prepare additive masterbatch: Mix the glass fiber masterbatch with mixed additives and melt-extrude them to obtain additive masterbatch; The mixed additives are composed of polysiloxane, ethylene zinc acrylate ion copolymer, oleic acid amide, silicon dioxide, phosphite, and lupetol; (3) Prepare nylon moisture-permeable film: Add the multi-block polyamide-polyurethane copolymer and the additive masterbatch into the masterbatch dryer in proportion for mixing, stirring, and drying. After drying, add them to the blown film machine for stirring, melting, and extruding into a continuous molten plastic strip. The extruded molten plastic forms a film bubble through the cooling and inflation of the air ring, and the film bubble is transformed into a film by squeezing with the chevron plate. After cooling and solidification, stretching, trimming, and winding, a nylon moisture-permeable film is obtained.

2. The preparation method of a nylon moisture permeable membrane according to claim 1, characterized in that, The multi-block polyamide-polyurethane copolymer described in steps (1) and (3) is a block copolymer of one of PA6, PA66, and PA56 and polyurethane, and the polyurethane content is 25-40%.

3. The preparation method of a nylon moisture permeable membrane according to claim 1, wherein, In step (1), the mass ratio of glass fiber, compatibilizer, and multi-block polyamide-polyurethane copolymer is 4:(0.5-1):(5.5-8).

4. The preparation method of a nylon moisture-permeable membrane according to claim 1, characterized in that, In step (1), the compatibilizer is a composition of maleic anhydride grafted compatibilizer and anti-glass fiber exposure agent combined in a mass ratio of 4:

1.

5. The preparation method of a nylon moisture permeable membrane according to claim 1, characterized in that, In step (2), the mass ratio of the glass fiber masterbatch to the mixed additives is (8-9):

1.

6. The preparation method of a nylon moisture-permeable membrane according to claim 1, characterized in that, In step (2), the mass ratio of polysiloxane, ethylene zinc acrylate ion copolymer, oleic acid amide, silicon dioxide, phosphite, and lupetol in the mixed additives is 2:0.5:1:4:1.5:

1.

7. The preparation method of a nylon moisture-permeable membrane according to claim 1, wherein, In step (3), the mass ratio of the multi-block polyamide-polyurethane copolymer to the additive masterbatch is (95-85):(5-15).

8. The preparation method of a nylon moisture-permeable membrane according to claim 1, wherein In step (3), the drying temperature is 90-95°C, and the drying time is 18-20h.

9. The preparation method of a nylon moisture-permeable membrane according to claim 1, characterized in that, In step (3), the blown film machine speed is 10-15m / min, the extrusion temperature is 180-215°C, the extrusion pressure is 3-15kg, the roll tension is 6-9kg, and the blow-up ratio is 1:2-4.

10. A nylon moisture-permeable membrane, characterized in that, The nylon moisture-permeable membrane is prepared by the method according to any one of claims 1-9; the thickness of the membrane is 4-5 microns, and the gram weight is 5-6.3 g / m 2 , the moisture permeability is 7950-8190 g / m 2 *24h, the breaking elongation rate is 285-312%, and the resilience rate is 8-13%.

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