阅读说明：本技术 一种防水透气薄膜及其制备方法 (Waterproof breathable film and preparation method thereof ) 是由 王冬梅 许雍 黄国华 俞军耀 何刚 张爱华 施祥 陆军 秦彦 王晓云 余佳奇 于 2021-08-06 设计创作，主要内容包括：本申请涉及塑料包装技术领域,尤其涉及一种防水透气薄膜及其制备方法。一种防水透气薄膜,包括如下重量份数的组分：低密度聚乙烯50-60份；线性低密度聚乙烯80-120份；中密度聚乙烯50-60份；高密度聚乙烯100-150份；活化无机超细填料200-300份；所述活化无机超细填料的制备步骤如下：先将无机超细填料预热,再真空搅拌烘干,干燥后加入偶联剂；再将无机超细填料与活化溶胶在碱性条件下加热混合,即可制得活化无机超细填料；其制备方法包括S1、母料制备；S2、流延成膜；S3、预热拉伸；S4、表面处理；S5、裁切成型。本申请的防水透气薄膜可用于卫生巾、纸尿裤等卫生用品中的防水层,其具有防水透气的优点。(The application relates to the technical field of plastic packaging, in particular to a waterproof breathable film and a preparation method thereof. A waterproof breathable film comprises the following components in parts by weight: 50-60 parts of low-density polyethylene; 80-120 parts of linear low-density polyethylene; 50-60 parts of medium-density polyethylene; 100 portions and 150 portions of high-density polyethylene; 200 portions and 300 portions of activated inorganic superfine filler; the preparation steps of the activated inorganic superfine filler are as follows: preheating the inorganic superfine filler, then stirring and drying in vacuum, and adding the coupling agent after drying; heating and mixing the inorganic superfine filler and the activated sol under an alkaline condition to obtain the activated inorganic superfine filler; the preparation method comprises the steps of S1, preparing master batch; s2, casting to form a film; s3, preheating and stretching; s4, surface treatment; and S5, cutting and forming. The waterproof breathable film can be used as a waterproof layer in sanitary products such as sanitary towels and paper diapers, and has the advantages of being waterproof and breathable.)

1. The waterproof breathable film is characterized by comprising the following components in parts by weight:

50-60 parts of low-density polyethylene;

80-120 parts of linear low-density polyethylene;

50-60 parts of medium-density polyethylene;

100 portions and 150 portions of high-density polyethylene;

200 portions and 300 portions of activated inorganic superfine filler;

the preparation steps of the activated inorganic superfine filler are as follows:

a. pretreatment: preheating the inorganic superfine filler, then stirring and drying in vacuum, adding the coupling agent after drying, and continuously stirring for pretreatment;

the particle size of the inorganic superfine filler is 1000-2000 meshes;

b. activation treatment: heating and mixing the pretreated inorganic superfine filler and the activated sol under an alkaline condition to obtain an activated inorganic superfine filler;

the activated sol is two or more of stearic acid, sodium bicarbonate, amino resin and polyethylene glycol.

2. The waterproof breathable film according to claim 1, characterized in that the specific processing steps of a are as follows: preheating the inorganic superfine filler to the temperature of 100-: (0.02-0.03) adding a coupling agent in a weight ratio, and carrying out pretreatment for 8-10min, wherein the coupling agent is a titanate coupling agent.

3. The waterproof breathable film according to claim 1, wherein the weight ratio of the inorganic ultrafine filler to the activated sol in b is 1: (0.3-0.5) mixing.

4. The waterproof breathable film according to claim 3, characterized in that said b is obtained by the following specific treatment steps: and (b) activating the inorganic superfine filler pretreated in the step a and the activated sol for 25-45min under the conditions that the pH value is 8-9, the temperature is 150-160 ℃, and the rotating speed is 500-800 r/min.

5. The waterproof breathable film according to claim 1, wherein the activated sol in b is prepared from sodium bicarbonate, amino resin and polyethylene glycol in a weight ratio of 1: (8-12): (2-3).

6. The waterproof breathable film of claim 1, wherein the inorganic ultrafine filler in a is composed of one or more of light calcium carbonate, nano silica, graphene and nano silver.

7. The waterproof breathable film according to claim 6, characterized in that said inorganic ultrafine filler is composed of light calcium carbonate, graphene and nanosilver in a weight ratio of 1: (0.2-0.3): (0.05-0.07).

8. A method for preparing a waterproof breathable film according to any one of claims 1 to 7, characterized in that it comprises the following steps:

s1, preparing a master batch: firstly, melting and mixing the components according to the corresponding weight parts to prepare a blend, and then extruding the blend from a forming die to prepare a master batch;

s2, casting film forming: extruding the master batch from a forming die, performing sheet casting, and performing quenching, cooling and shaping to obtain a film blank;

s3, preheating and stretching: preheating a film blank, longitudinally stretching the film blank step by step, and performing heat setting treatment after the stretching is finished to obtain a plastic film;

s4, surface treatment: carrying out corona treatment on the plastic film, and continuously introducing mixed gas of hydrogen, ammonia and nitrogen in the corona treatment process to prepare a cross-linked modified film;

s5, cutting and forming: and rolling the cross-linked modified film and cutting edges to obtain the waterproof breathable film.

9. The waterproof breathable film and the preparation method thereof according to claim 8, wherein the specific steps of S3 are as follows: preheating the film blank at the temperature of 100-minus-plus-120 ℃, sequentially stretching the film blank in the longitudinal direction at the stretching ratios of 2-3, 3-5 and 5-8, the stretching temperatures of 100-minus-plus-105 ℃, 105-minus-plus-110 ℃ and 110-minus-plus-120 ℃, and then performing heat setting on the film at the temperature of 100-minus-plus-140 ℃ to obtain the waterproof breathable film.

10. The waterproof breathable film and the preparation method thereof as claimed in claim 8, wherein the AC voltage during the corona treatment process is 8000-10000V/m²The treatment time is 0.5-1.0s, the aeration flow is 1.0-2.0L/min, and the volume ratio of the hydrogen to the ammonia to the nitrogen is 1: (1-2): (10-15) introducing and pressurizing to 38-42 MPa.

Technical Field

The application relates to the technical field of plastic films, in particular to a waterproof breathable film and a preparation method thereof.

Background

Nowadays, with the improvement of living standard of people, in order to meet more demands of people, various sanitary products are appeared in daily life of people, wherein, baby paper diapers, sanitary napkins, panty liners, adult paper diapers and incontinence products are taken as examples. The quality of the sanitary product depends on the waterproof and breathable capability of the waterproof layer, the existing waterproof layer is mainly made of a waterproof and breathable film, and is an inorganic filler filled polymer composite film material with a micro-pore channel structure, and the micro-pores allow gas to pass through but are blocked because the liquid diameter is larger than the diameter of the micro-pores, so that the sanitary product has the characteristics of ventilation and impermeability.

The main materials of the waterproof breathable film in the related technology are polyethylene and inorganic filler, and the preparation process comprises the following steps: firstly, mixing inorganic filler and polyethylene and putting the mixture into a double-screw extruder to prepare master batch special for the breathable film; cooling to form a film by adopting a tape casting method; and finally, stretching the film to separate the film matrix from the surfaces of the filler particles to form micropores, and generating mutually communicated micro-fine pore passages among the filler particles so as to prepare the microporous breathable film.

However, the inorganic filler and the polyethylene in the above technology are simply kneaded under heating conditions, the compatibility of the inorganic filler and the polyethylene is poor, the binding force is weak, and then the micropore forming quality is poor in the subsequent film stretching process, so that the good waterproof and breathable capability of the film cannot be guaranteed.

Disclosure of Invention

In order to endow the film with good waterproof and breathable capabilities, the application provides a waterproof and breathable film and a preparation method thereof.

In a first aspect, the present application provides a waterproof breathable film that employs the following technical solution:

the waterproof breathable film is characterized by comprising the following components in parts by weight:

50-60 parts of low-density polyethylene;

80-120 parts of linear low-density polyethylene;

50-60 parts of medium-density polyethylene;

100 portions and 150 portions of high-density polyethylene;

200 portions and 300 portions of activated inorganic superfine filler;

the preparation steps of the activated inorganic superfine filler are as follows:

a. pretreatment: preheating the inorganic superfine filler, then stirring and drying in vacuum, adding the coupling agent after drying, and continuously stirring for pretreatment;

the particle size of the inorganic superfine filler is 1000-2000 meshes;

b. activation treatment: heating and mixing the pretreated inorganic superfine filler and the activated sol under an alkaline condition to obtain an activated inorganic superfine filler;

the activated sol is two or more of stearic acid, sodium bicarbonate, amino resin and polyethylene glycol.

By adopting the technical scheme, the medium-density polyethylene and the high-density polyethylene can be used as frameworks, and a large number of supports are formed by inserting and crosslinking between the frameworks under the crosslinking filling action of the low-density polyethylene and the linear low-density polyethylene, so that the complexity of the film structure is greatly enhanced, more binding sites can be provided for activating the inorganic superfine filler, and the micropore forming is facilitated.

When the activated inorganic superfine filler in the particle size range is subjected to pretreatment and activation treatment, the activated inorganic superfine filler can be subjected to mutual crosslinking modification under the coupling action of a coupling agent with activated sol under the condition of an alkaline heating condition, the surface binding capacity of the activated inorganic superfine filler is greatly enhanced, the activated inorganic superfine filler has better compatibility with a film structure, and the activated inorganic superfine filler is more easily and fully dispersed and combined on the surface of the film structure, so that the inorganic superfine filler can ensure the forming effect of the inorganic superfine filler with lower weight ratio, the destructiveness on an organic film structure is reduced, and then in the subsequent micropore forming process, micropores are higher in forming quality, are compact and discontinuous, are communicated with one another to form micropores, and endow the film with excellent waterproof and breathable performance.

Preferably, the specific processing steps of a are as follows: preheating the inorganic superfine filler to the temperature of 100-: (0.02-0.03) adding a coupling agent in a weight ratio, and carrying out pretreatment for 8-10min, wherein the coupling agent is a titanate coupling agent.

By adopting the technical scheme, the inorganic superfine filler pretreated under the process conditions has a good crosslinking effect under the catalysis of the coupling agent, so that the modification effect of the inorganic superfine filler and the activated sol is ensured, namely the inorganic superfine filler can be changed from hydrophilicity to lipophilicity, and the monomolecular film formed by coating and combining the surface of the inorganic superfine filler is more stable and compact in structure.

Preferably, the weight ratio of the inorganic superfine filler to the activated sol in the step b is 1: (0.3-0.5) mixing.

By adopting the technical scheme, the activated sol under the weight ratio has a good coating and combining effect on the inorganic superfine filler, namely, the monomolecular film structure formed by coating and combining the surface of the inorganic superfine filler is more stable and compact, so that the binding property and the dispersity of the inorganic superfine filler and the film structure are ensured, and the formation of micropores in the subsequent stretching process is facilitated.

Preferably, the specific processing steps of b are as follows: and (b) activating the inorganic superfine filler pretreated in the step a and the activated sol for 25-45min under the conditions that the pH value is 8-9, the temperature is 150-160 ℃, and the rotating speed is 500-800 r/min.

By adopting the technical scheme, the inorganic superfine filler treated at the pH value and the activation temperature has better modification and combination effect with the activation sol, a compact monomolecular film can be formed on the surface of the inorganic superfine filler, the crosslinking and combination capability of the monomolecular film is stronger, and after the inorganic superfine filler is combined with the film structure, the micropore forming quality is higher, and the waterproof performance is not easily influenced by continuous micropore forming.

Preferably, the activated sol in b is prepared from sodium bicarbonate, amino resin and polyethylene glycol in a weight ratio of 1: (8-12): (2-3).

By adopting the technical scheme, the activated sol under the components and the proportion can be coated and combined on the surface of the inorganic superfine filler to form a monomolecular film with a more compact structure under the alkaline condition, the monomolecular film takes amino as a main net frame and can be fully combined with the film structure by matching with the lubricating and loosening effects of polyethylene glycol and/or sodium bicarbonate, and the sodium bicarbonate can be heated to decompose carbon dioxide gas in the subsequent stretching and forming process of micropores, so that the forming quality of the micropore channels is further improved.

Preferably, the inorganic ultrafine filler in a is composed of one or more of light calcium carbonate, nano silica, graphene and nano silver.

By adopting the technical scheme, the inorganic superfine filler in the components has better bonding performance after pretreatment and activation treatment, and the addition of the fillers such as light calcium carbonate, nano silicon dioxide, graphene and nano silver can play a role in enhancing and improving the film structure, namely enhancing the mechanical strength and the processing performance of the film structure, and is beneficial to micropore forming in the subsequent stretching process.

Preferably, the inorganic ultrafine filler is prepared from light calcium carbonate, graphene and nano silver in a weight ratio of 1: (0.2-0.3): (0.05-0.07).

By adopting the technical scheme, the inorganic superfine filler prepared from the components and the proportion has a certain compounding effect, wherein the light calcium carbonate can enhance the strength of the film structure and can ensure the forming quality and the mutual communication effect of micropores in the subsequent micropore forming process, and the nanoscale graphene and the nanoscale silver can strengthen the micropore structure and endow the film with certain antibacterial performance.

In a second aspect, the present application provides a method for preparing a waterproof breathable film, which adopts the following technical scheme:

a preparation method of a waterproof breathable film comprises the following steps:

s1, preparing a master batch: firstly, melting and mixing the components according to the corresponding weight parts to prepare a blend, and then extruding the blend from a forming die to prepare a master batch;

s2, casting film forming: extruding the master batch from a forming die, performing sheet casting, and performing quenching, cooling and shaping to obtain a film blank;

s3, preheating and stretching: preheating a film blank, longitudinally stretching the film blank step by step, and performing heat setting treatment after the stretching is finished to obtain a plastic film;

s4, surface treatment: carrying out corona treatment on the plastic film, and continuously introducing mixed gas of hydrogen, ammonia and nitrogen in the corona treatment process to prepare a cross-linked modified film;

s5, cutting and forming: and rolling the cross-linked modified film and cutting edges to obtain the waterproof breathable film.

By adopting the technical scheme, the thickness and the performance of the waterproof breathable film prepared by the process steps are relatively stable and uniform, and the micropore forming quality of the waterproof breathable film is greatly improved after the waterproof breathable film is subjected to special processes such as quenching and shaping, step-by-step distribution stretching, corona treatment and the like.

Preferably, the specific steps of S3 are as follows: preheating the film blank at the temperature of 100-minus-plus-120 ℃, sequentially stretching the film blank in the longitudinal direction at the stretching ratios of 2-3, 3-5 and 5-8, the stretching temperatures of 100-minus-plus-105 ℃, 105-minus-plus-110 ℃ and 110-minus-plus-120 ℃, and then performing heat setting on the film at the temperature of 100-minus-plus-140 ℃ to obtain the waterproof breathable film.

Through adopting above-mentioned technical scheme, the film after above-mentioned distribution is stretched step by step, and its thickness is more homogeneous stable, and micropore shaping quality is higher, and the individual layer structure micropore is fine and close and discontinuous, and adjacent layer microporous construction communicates each other, has ensured waterproof breathable film's air permeability and waterproof performance then.

Preferably, the alternating voltage in the corona treatment process is 8000-10000V/m²The treatment time is 0.5-1.0s, the aeration flow is 1.0-2.0L/min, and the volume ratio of the hydrogen to the ammonia to the nitrogen is 1 (1-2): (10-15) introducing and pressurizing to 38-42 MPa.

Through adopting above-mentioned technical scheme, the film structure after above-mentioned corona treatment, its micropore shaping quality is higher, and the microporous structure is more stable, can generate a small amount of ammonia among the corona treatment process, and it can promote amino resin when further grafting is modified, can cooperate with nitrogen gas for microporous structure is more loose, has ensured micropore intercommunication back micropore.

In summary, the present application has the following beneficial effects:

1. according to the method, the inorganic superfine filler is activated, so that the binding capacity of the surface of the inorganic superfine filler and the compatibility of the inorganic superfine filler with a film structure are greatly improved, and then the inorganic superfine filler is easily and fully dispersed and bound to the surface of the film structure, so that micropore formation is facilitated, and the waterproof and air-permeable performance of the film is improved;

2. according to the method, the stability and the forming quality of the microporous structure are guaranteed through the activated sol and the reaction conditions, micropores of a single-layer structure are compact and discontinuous, and meanwhile, micropores of adjacent-layer structures are good in communication effect, loose in whole and high in forming quality of microporous channels;

3. according to the method, the surface of the film structure is treated by special processes such as quenching setting, gradual stretching and corona treatment, so that the excellent mechanical property and micropore forming quality of the surface of the film structure are given, and the waterproof and breathable performance of the film is further guaranteed.

Detailed Description

The present application will be described in further detail with reference to examples.

The raw materials used in the examples of the present application are commercially available, except for the following specific descriptions:

low density polyethylene, No. 2426H, purchased from high standing plastics limited of guan city;

linear low density polyethylene, trade designation DFDA-2001T, available from Xintong Plastic materials, Inc., of Dongguan city;

medium density polyethylene, purchased from Hongkong new materials, Inc. of Dongguan;

high density polyethylene, designation LH606, was purchased from north plastic new materials science and technology limited, of guan dong;

amino resin, CAS 9003-08-1, available from Shandong PolyChemicals, Inc.;

polyethylene glycol, CAS 25322-68-3, purchased from south china zhiding commerce and trade limited;

titanate coupling agent CAS 67691-13-8, purchased from ancient cooking vessel plastics chemical Co., Ltd;

precipitated calcium carbonate, CAS 279-897-3, purchased from Chondran chemical Co., Ltd;

graphene, model AM-C3-065-1, available from Yamei nanotechnology, Inc., Zhejiang;

nano silver, average particle size 20nm, was purchased from nanometer materials science and technology, Inc. available in Hebei Seina.

Preparation example

Preparation example 1

An activated inorganic superfine filler is prepared by the following preparation steps:

a. pretreatment: preheating the inorganic superfine filler to 90 ℃, stirring and drying the inorganic superfine filler in vacuum at the rotating speed of 2000r/min until the water content is lower than 0.3 percent, and then mixing the inorganic superfine filler and the water according to the weight ratio of 1: adding coupling agent in the weight ratio of 0.01, and pretreating for 6 min;

wherein the coupling agent is titanate coupling agent;

the particle size of the inorganic superfine filler is 1000-2000 meshes;

the inorganic superfine filler is light calcium carbonate;

b. activation treatment: b, mixing the pretreated inorganic superfine filler and the activated sol in the step a according to the weight ratio of 1: 0.2 activating for 15min under the conditions that the pH value is 7, the temperature is 140 ℃ and the rotating speed is 300 r/min;

the activated sol is composed of sodium bicarbonate and amino resin according to the weight ratio of 1: 1.

Preparation example 2

An activated inorganic ultrafine filler, which is different from the preparation example 1 in that a is specifically treated by the following steps: preheating the inorganic superfine filler to 100 ℃, stirring and drying the inorganic superfine filler in vacuum at the rotating speed of 3000r/min, and after the water content of the inorganic superfine filler is lower than 0.3 percent, adding the inorganic superfine filler into the mixture according to the proportion of 1: 0.02 weight ratio, adding coupling agent, and pretreating for 8 min.

Preparation example 3

An activated inorganic ultrafine filler, which is different from the preparation example 1 in that a is specifically treated by the following steps: preheating the inorganic superfine filler to 110 ℃, stirring and drying the inorganic superfine filler in vacuum at the rotating speed of 4000r/min, and after the water content of the inorganic superfine filler is lower than 0.3 percent, adding the inorganic superfine filler into the mixture according to the proportion of 1: 0.025 weight percent of the total weight of the slurry was pretreated for 9 min.

Preparation example 4

An activated inorganic ultrafine filler, which is different from the preparation example 1 in that a is specifically treated by the following steps: preheating the inorganic superfine filler to 120 ℃, stirring and drying the inorganic superfine filler in vacuum at the rotating speed of 5000r/min, and after the water content of the inorganic superfine filler is lower than 0.3 percent, adding the inorganic superfine filler into the mixture according to the proportion of 1: 0.03 weight ratio of the coupling agent was added and the pretreatment was carried out for 10 min.

Preparation example 5

An activated inorganic ultrafine filler, which is different from the preparation example 1 in that a is specifically treated by the following steps: preheating the inorganic superfine filler to 130 ℃, stirring and drying the inorganic superfine filler in vacuum at the rotating speed of 6000r/min until the water content is lower than 0.3 percent, and then mixing the inorganic superfine filler with the water according to the weight ratio of 1: 0.04 weight ratio, adding coupling agent, and pretreating for 12 min.

Preparation example 6

An activated inorganic ultrafine filler is different from the preparation example 1 in that the inorganic ultrafine filler is prepared from light calcium carbonate, graphene and nano silver in a weight ratio of 1: 0.1: 0.02 composition.

Preparation example 7

An activated inorganic ultrafine filler is different from the preparation example 1 in that the inorganic ultrafine filler is prepared from light calcium carbonate, graphene and nano silver in a weight ratio of 1: 0.2: 0.05 composition.

Preparation example 8

An activated inorganic ultrafine filler is different from the preparation example 1 in that the inorganic ultrafine filler is prepared from light calcium carbonate, graphene and nano silver in a weight ratio of 1: 0.25: 0.06.

Preparation example 9

An activated inorganic ultrafine filler is different from the preparation example 1 in that the inorganic ultrafine filler is prepared from light calcium carbonate, graphene and nano silver in a weight ratio of 1: 0.3: 0.07.

Preparation example 10

An activated inorganic ultrafine filler is different from the preparation example 1 in that the inorganic ultrafine filler is prepared from light calcium carbonate, graphene and nano silver in a weight ratio of 1: 0.4: 0.1.

Preparation example 11

An activated inorganic ultrafine filler, which is different from preparation example 1 in that the inorganic ultrafine filler and the activated sol in the b are mixed in a weight ratio of 1: 0.3 mixing.

Preparation example 12

An activated inorganic ultrafine filler, which is different from preparation example 1 in that the inorganic ultrafine filler and the activated sol in the b are mixed in a weight ratio of 1: 0.4 mixing.

Preparation example 13

An activated inorganic ultrafine filler, which is different from preparation example 1 in that the inorganic ultrafine filler and the activated sol in the b are mixed in a weight ratio of 1: 0.5 mixing.

Preparation example 14

An activated inorganic ultrafine filler, which is different from preparation example 1 in that the inorganic ultrafine filler and the activated sol in the b are mixed in a weight ratio of 1: 0.6 mixing.

Preparation example 15

An activated inorganic ultrafine filler, which is different from the preparation example 1 in that the specific processing steps of b are as follows: and (b) activating the pretreated inorganic superfine filler and the activated sol in the step a for 25min under the conditions that the pH value is 8, the temperature is 150 ℃ and the rotating speed is 500 r/min.

Preparation example 16

An activated inorganic ultrafine filler, which is different from the preparation example 1 in that the specific processing steps of b are as follows: and (b) activating the pretreated inorganic superfine filler and the activated sol in the step a for 35min under the conditions that the pH value is 8.5, the temperature is 155 ℃, and the rotating speed is 650 r/min.

Preparation example 17

An activated inorganic ultrafine filler, which is different from the preparation example 1 in that the specific processing steps of b are as follows: and (b) activating the pretreated inorganic superfine filler and the activated sol in the step a for 45min under the conditions that the pH value is 9, the temperature is 160 ℃ and the rotating speed is 800 r/min.

Preparation example 18

An activated inorganic ultrafine filler, which is different from the preparation example 1 in that the specific processing steps of b are as follows: and (b) activating the pretreated inorganic superfine filler and the activated sol in the step a for 55min under the conditions that the pH value is 10, the temperature is 170 ℃ and the rotating speed is 1000 r/min.

Preparation example 19

An activated inorganic ultrafine filler, which is different from preparation example 1 in that in b, the activated sol is prepared from sodium bicarbonate, amino resin and polyethylene glycol in a weight ratio of 1: 6: 1.

Preparation example 20

An activated inorganic ultrafine filler, which is different from preparation example 1 in that in b, the activated sol is prepared from sodium bicarbonate, amino resin and polyethylene glycol in a weight ratio of 1: 8: 2.

Preparation example 21

An activated inorganic ultrafine filler, which is different from preparation example 1 in that in b, the activated sol is prepared from sodium bicarbonate, amino resin and polyethylene glycol in a weight ratio of 1: 10: 2.5.

Preparation example 22

An activated inorganic ultrafine filler, which is different from preparation example 1 in that in b, the activated sol is prepared from sodium bicarbonate, amino resin and polyethylene glycol in a weight ratio of 1: 12: 3, and (3).

Preparation example 23

An activated inorganic ultrafine filler, which is different from preparation example 1 in that in b, the activated sol is prepared from sodium bicarbonate, amino resin and polyethylene glycol in a weight ratio of 1: 14: 4.

Examples

Example 1

The waterproof breathable film comprises the following components in the amount shown in Table 1, and is prepared by the following steps:

s1, preparing a master batch: firstly, putting the components in a double-screw extruder according to the corresponding weight parts for melt kneading to prepare a blend, and then extruding the blend from a forming die to prepare a master batch, wherein the temperature of the double-screw extruder is controlled from a feed inlet to a discharge outlet to be 205 ℃, 215 ℃, 225 ℃, 230 ℃ and 235 ℃;

s2, casting film forming: extruding the master batch from a forming die to form a sheet-shaped casting, and performing quenching, cooling and shaping, namely performing double-roller cooling within 0.3s to room temperature to obtain a film blank;

s3, preheating and stretching: preheating a film blank at 90 ℃, sequentially stretching the film blank step by step along the longitudinal direction at stretching ratios of 1, 2 and 4 and stretching temperatures of 90 ℃, 95 ℃ and 100 ℃, and then performing heat setting on the film blank at 90 ℃ to obtain a plastic film;

s4, surface treatment: performing corona treatment on the plastic film for 0.3s, and the high-frequency alternating voltage is 7000V/m²And in the corona treatment process, the volume ratio of 1: 0.5: 8 introducing hydrogen, ammonia gas and nitrogen gas, wherein the flow rate of the introduced gas is 0.5L/min, and pressurizing to 36Mpa to obtain the cross-linked modified film.

S5, cutting and forming: and winding the crosslinked modified film, and cutting edges according to actual production requirements to obtain the waterproof breathable film.

Examples 2 to 6

A waterproof breathable film which differs from example 1 in that the components and their respective weights are as shown in table 1.

TABLE 1 Components and weights (kg) thereof in examples 1-6

Examples 7 to 28

A waterproof breathable film is different from the waterproof breathable film in example 1 in that the use conditions of the used activated inorganic superfine filler are different, and the specific corresponding relation is shown in Table 2.

TABLE 2 comparison of the use of activated inorganic ultrafine fillers in examples 7-28

Example 29

The preparation method of the waterproof breathable film is different from that of the embodiment 1 in that the specific steps of S1 are as follows: preheating the film blank at 100 ℃, sequentially stretching the film blank in the longitudinal direction at stretching ratios of 2, 3 and 5 and stretching temperatures of 100 ℃, 105 ℃ and 110 ℃, and then performing heat setting on the film blank at 100 ℃ to obtain the plastic film.

Example 30

The preparation method of the waterproof breathable film is different from that of the embodiment 1 in that the specific steps of S1 are as follows: preheating the film blank at 110 ℃, sequentially stretching the film blank in a longitudinal direction by stretching ratios of 3, 4 and 6 at a stretching temperature of 105 ℃, 110 ℃ and 110 ℃, and then performing heat setting on the film blank at 120 ℃ to obtain the plastic film.

Example 31

The preparation method of the waterproof breathable film is different from that of the embodiment 1 in that the specific steps of S1 are as follows: preheating the film blank at 120 ℃, sequentially stretching the film blank in a longitudinal direction step by step at stretching ratios of 3, 5 and 8 and stretching temperatures of 105 ℃, 110 ℃ and 120 ℃, and then performing heat setting on the film blank at 140 ℃ to obtain the plastic film.

Example 32

The preparation method of the waterproof breathable film is different from that of the embodiment 1 in that the specific steps of S1 are as follows: preheating the film blank at 130 ℃, sequentially stretching the film blank in a longitudinal direction step by step at stretching ratios of 4, 6 and 10 and stretching temperatures of 110 ℃, 120 ℃ and 130 ℃, and then performing heat setting on the film blank at 150 ℃ to obtain the plastic film.

Example 33

The preparation method of the waterproof breathable film is different from that of the embodiment 1 in that the specific steps of S4 are as follows: performing corona treatment on the plastic film for 0.5s, and the high-frequency alternating-current voltage is 8000V/m²And in the corona treatment process, the volume ratio of 1: 1: 10 introducing hydrogen, ammonia and nitrogen with the flow rate of 1.0L/min and pressurizing to 38Mpa to obtain the cross-linked modified film.

Example 34

The preparation method of the waterproof breathable film is different from that of the embodiment 1 in that the specific steps of S4 are as follows: performing corona treatment on the plastic film for 0.75s, wherein the high-frequency alternating voltage is 9000V/m²And in the corona treatment process, the volume ratio of 1: 1.5: 12.5 introducing hydrogen, ammonia and nitrogen, wherein the flow rate of the introduced gas is 1.5L/min, and pressurizing to 40Mpa to obtain the cross-linked modified film.

Example 35

The preparation method of the waterproof breathable film is different from that of the embodiment 1 in that the specific steps of S4 are as follows: performing corona treatment on the plastic film for 0.10s, wherein the high-frequency alternating voltage is 10000V/m²And in the corona treatment process, the volume ratio of 1: 2: and 15, introducing hydrogen, ammonia gas and nitrogen gas, wherein the flow rate of the introduced gas is 2.0L/min, and pressurizing to 42Mpa to obtain the cross-linked modified film.

Example 36

The preparation method of the waterproof breathable film is different from that of the embodiment 1 in that the specific steps of S4 are as follows: performing corona treatment on the plastic film for 0.12s, wherein the high-frequency alternating voltage is 11000V/m²And in the corona treatment process, the volume ratio of 1: 3.5: and (17) introducing hydrogen, ammonia gas and nitrogen gas, wherein the flow rate of the introduced gas is 2.5L/min, and pressurizing to 44Mpa to obtain the cross-linked modified film.

Comparative example

Comparative example 1

A method for preparing a waterproof breathable film, which is different from that of example 1 in that inorganic ultrafine filler is not subjected to activation treatment.

Performance test

Detection method

The plastic films obtained in examples 1 to 36 and comparative example 1 were selected as test objects, 10 specimens were prepared from each group, and the water vapor transmission amount (WVT) and the hydrostatic pressure (WP) resistance were measured, respectively, and averaged in table 3. The specific detection steps and the detection standard refer to GB/T1037-.

TABLE 3 Performance test results

As can be seen by combining examples 1-6 with comparative example 1 and by combining Table 3, the water vapor transmission rates of the samples of examples 1-6 during the test were all higher than 5900g/m²24hr, and the hydrostatic pressure resistance is higher than 72.0cm/H₂O。

The ultrafine inorganic filler of comparative example 1 was not subjected to activation treatment, and the film obtained therefrom had a water vapor transmission rate of only 3210.3g/m²24hr, the hydrostatic pressure resistance is only 68.3cm/H₂O, the waterproof and air-permeable capacity is greatly reduced.

Example 3 is the most preferred example, the water vapor transmission rate of the test specimen during the test is as high as 7242.6g/m²24hr, hydrostatic pressure up to 88.1cm/H₂And O. Therefore, the components in the proportion have the best matching effect, the polyethylene film has the most complex structure, a large number of binding sites can be provided for the activated inorganic superfine filler, the dispersing and binding effect of the activated inorganic superfine filler is optimal, and meanwhile, the inorganic superfine filler can ensure the forming quality of micropores in a lower weight ratio, so that the film is endowed with excellent waterproof and breathable capacity.

As can be seen by combining examples 1, 7-10 and Table 3, the water vapor transmission rates of the samples of examples 7-10 during the test were all higher than 5900g/m²24hr, and the hydrostatic pressure resistance is higher than 73.5cm/H₂O。

Example 8 is a preferred example, the water vapor transmission rate of the test specimen during the test is as high as 6170.6g/m²24hr, hydrostatic pressure resistance up to 53.6cm/H₂And O. Therefore, the preparation example 3 is the optimal process condition, that is, the inorganic superfine filler pretreated under the process condition has the best crosslinking modification effect with the activated sol under the catalysis of the coupling agent, that is, the monomolecular film formed by coating and combining the surface of the inorganic superfine filler has the most stable and compact structure, and the waterproof and breathable performance of the prepared film is further ensured.

As can be seen by combining examples 1, 11-15 and Table 3, the samples of examples 11-15 all had water vapor transmission rates greater than 6200g/m during the test²24hr, and the hydrostatic pressure resistance is higher than 75.0cm/H₂O。

Example 13 is a preferred example of a sample having a water vapor transmission rate during testing of up to 7648.2g/m²24hr, hydrostatic pressure resistance up to 93.0cm/H₂And O. It can be seen that the inorganic ultrafine filler in preparation example 8 is the optimal mixture ratio, i.e. the inorganic ultrafine filler is composed of light calcium carbonate and grapheneAnd nano silver in a weight ratio of 1: 0.25: 0.06, the three have certain compounding effect, and the microporous structure can be reinforced while the forming quality and the mutual communication effect of micropores can be ensured in the subsequent micropore forming process, so that the waterproof and breathable performance of the film is ensured.

As can be seen by combining example 1, examples 16 to 19 and Table 3, the water vapor transmission rates of the samples of examples 16 to 19 were all higher than 6600g/m during the test²24hr, and the hydrostatic pressure resistance is higher than 80.0cm/H₂O。

Example 17 is a preferred example, the water vapor transmission rate of the test specimen during the test is as high as 6975.6g/m²24hr, hydrostatic pressure resistance up to 84.7cm/H₂And O. It can be seen that the optimal mixing ratio in preparation example 12 is, i.e., the weight ratio of the inorganic ultrafine filler to the activated sol is 1: 0.4, the monomolecular film structure formed by coating and combining the surfaces of the inorganic superfine fillers is most stable and compact, and the combination property and the dispersity between the inorganic superfine fillers and the film structure are optimal, so that the film is endowed with excellent waterproof and breathable performance.

As can be seen by combining example 1, examples 20 to 23 and Table 3, the water vapor transmission rates of the samples of examples 20 to 23 during the test were all higher than 6500g/m²24hr, and the hydrostatic pressure resistance is higher than 81.0cm/H₂O。

Example 21 is the most preferred example, the water vapor transmission rate of the test specimen during the test is as high as 6787.8g/m²24hr, hydrostatic pressure resistance up to 82.6cm/H₂And O. It can be seen that the activation treatment process in preparation example 16 is the optimal process, i.e. the inorganic ultrafine filler treated at the above pH and activation temperature has the best modification and combination effect with the activated sol, the cross-linking and combination ability of the monomolecular film is the strongest, and the waterproof and breathable performance is not easily affected by the continuous formation of micropores.

As can be seen by combining example 1, examples 24 to 28 and Table 3, the water vapor transmission rates of the samples of examples 24 to 28 were all higher than 6200g/m during the test²24hr, and the hydrostatic pressure resistance is higher than 77.0cm/H₂O。

Example 26 is a preferred example of water evaporation of a sample during testingThe air transmission rate is as high as 7677.2g/m²24hr, hydrostatic pressure resistance up to 93.4cm/H₂And O. It can be seen that the activated sol in preparation example 21 is the optimal mixture ratio, that is, the activated sol is prepared from sodium bicarbonate, amino resin and polyethylene glycol according to the weight ratio of 1: 10: 2.5, the coating combination formed single-component structure on the surface of the inorganic superfine filler is the most compact, the cross-linking combination property is the strongest, the single-component structure can be fully combined with a film structure, the sodium bicarbonate can be heated to decompose carbon dioxide gas in the subsequent stretching forming micropore process, and the polyethylene glycol is matched to have a certain lubricating and loosening effect, so that the forming quality of micropores and micropore channels is ensured.

As can be seen by combining example 1, examples 29 to 32 and Table 3, the water vapor transmission rates of the samples of examples 29 to 32 during the test were all higher than 6600g/m²24hr, and the hydrostatic pressure resistance is higher than 82.0cm/H₂O。

Example 30 is a preferred example, the water vapor transmission rate of the test specimen during the test is as high as 6911.1g/m²24hr, hydrostatic pressure resistance up to 84.0cm/H₂And O. Therefore, the preheating and stretching process is the optimal process, namely the gradually stretched film has the highest micropore forming quality, the micropores of a single-layer structure are compact and discontinuous, and the micropore structures of adjacent layers are communicated with each other, so that the film is endowed with excellent air permeability and waterproof performance.

As can be seen by combining example 1, examples 33-36 and Table 3, the samples of examples 20-23 all had water vapor transmission rates greater than 6700g/m during the testing process²24hr, and the hydrostatic pressure resistance is higher than 84.0cm/H₂O。

Example 34 is a preferred example, the water vapor transmission rate of the test specimen during the test is as high as 7049.3g/m²24hr, hydrostatic pressure resistance up to 85.7cm/H₂And O. It can be seen that the corona process in preparation example 34 is an optimal process, that is, under the above-mentioned voltage and ventilation conditions, the molding quality of the micropores is highest, the microporous structure is stable, and the corona process can be matched with nitrogen while promoting further graft modification of the amino resin, so that the microporous structure is looser, and the microporous channel after the micropores are communicated is ensured.

The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.