KR20050018788A - An air permeable and waterproof multi-layer sheet, and a method of manufacturing for the same - Google Patents

Abstract

PURPOSE: Provided are an air-permeable and waterproof multi-layer sheet and its manufacturing method, which reduces production cost, makes quality control easy, simplifies production process and facilities by manufacturing the sheet in a one-step extrusion coating process. CONSTITUTION: The air-permeable and waterproof multi-layer sheet is manufactured by extrusion-coating a base(1) on a cooling roll with a coating composition by a melt extrusion coating machine. The coating composition consists of: a thermoplastic resin mixture, which comprises 60-95wt% of at least one main ingredient(thermoplastic resins having relatively low crystallization temperature) and 5-40 wt% of at least one accessory ingredient(thermoplastic resins having 10 deg.C higher than crystallization temperature of the main ingredient); foaming agent; inorganic particles; and process aid. The base is selected from a group consisting of a paper, non-woven fabric, synthetic film and fabric.

Description

Breathable waterproof multi-layer sheet and its manufacturing method {An air permeable and waterproof multi-layer sheet, and a method of manufacturing for the same}

The present invention relates to a breathable waterproof multilayer sheet having a breathable waterproof layer (2) having amorphous irregular micropores (3) on a substrate (1), and a method of manufacturing the same. The present invention relates to a method for producing the breathable waterproof multilayer sheet by one step process of extrusion coating a composition for coating comprising at least one thermoplastic resin onto a substrate (1).

With the development of human civilization and science and technology, the materials used in human life are also evolving and developing.

In particular, in recent years, the demand for a product that provides convenience and functionality for use as a living material, in addition to the physical properties of simple materials, is rapidly increasing.

The breathable waterproof film was developed to be laminated on a substrate suitable for the purpose to provide comfort and convenience by blocking water from direct contact with water and allowing air or water vapor to pass therethrough. Is a breathable waterproof multilayer sheet such as garment, disposable sanitary napkin and the like.

According to the current trend of pursuing convenience, comfort, and functionality in various living materials, products that require breathable waterproof function are increasing.

Conventional techniques for making such breathable waterproof multi-layer sheet products are composed of two stages, a technique for manufacturing a breathable film and a technique for manufacturing a laminated product using the same, the breathable film used here It is being made in different ways.

The first method is to prepare a material containing a certain amount of inorganic filler or the like in the resin, melt and form a film sheet, and then perform uniaxial stretching or biaxial stretching or rolling to induce fine cracking of the film. It is a method of inducing the formation of pores and irregularities.

As a prior patent technology corresponding thereto, there are Republic of Korea Patent No. 1995-0002889, Republic of Korea Patent No. 10-0189265, Republic of Korea Patent No. 10-0197902, Republic of Korea Patent No. 10-0439459.

The second method is a process of preparing a solution in which a polyurethane or EVA resin is dissolved, coating the film on a release paper, and then drying the film to form a film on the release paper, and then laminating the formed film onto a fabric or nonwoven fabric with desired peeling. It is a method of lamination through.

Prior patent technology corresponding thereto includes Korean Patent Publication No. 10-2004-0065859.

Conventional techniques for producing a breathable waterproof multilayer sheet include (i) a step of preparing a special material (composition), (ii) a film forming step, (i) a pore forming step, and (i) a layer of laminating a breathable film on a substrate. It consists of a process.

As described above, in order to manufacture a breathable waterproof multilayer sheet according to the prior art, (i) a special material (resin composition for forming a breathable waterproof layer) must be prepared to express breathability, and (ii) stretching, rolling, etc. in addition to general film forming equipment. Additional equipment was needed, and (i) very careful process control was needed to ensure breathability throughout the process.

Therefore, the breathable film thus manufactured is expensive, and additionally, laminating costs such as lamination are required, and thus, expensive laminating costs are required, and additional equipment worth hundreds of millions or more is required. Will be needed.

The cost for breathable waterproof lamination on substrates such as paper, nonwoven fabrics, and fabrics is three times or more for breathable films using materials containing inorganic fillers, and breathability using resins such as polyurethane, compared to general resin layer lamination. For film it takes five times or more.

Therefore, it is difficult to apply when the breathable waterproof multilayer sheet product is not expensive.

In addition, there is a difficulty in expression and quality control through a multi-step process.

In particular, in the prior art, since each of the multi-step processes for laminating a breathable waterproof layer is a process of changing the microstructure or the macrostructure, the factors of each process directly affect the characteristics or the quality of the product. do.

In order to solve the problems of the prior art, the present invention is to provide a method for simplifying the step of forming a breathable waterproof layer (film) and the step of laminating it on a substrate in one step process.

In particular, the present invention is to provide a method for simplifying the manufacturing process to facilitate the quality control and at the same time reduce the manufacturing cost, and the development of various breathable waterproof multilayer sheets such as building materials without the introduction of expensive equipment do.

In order to achieve the above problems, the method of manufacturing a breathable waterproof multilayer sheet of the present invention has a crystallization temperature of 10 ° C. or more than 60-95 wt% of one or more thermoplastic resins having a relatively low crystallization temperature and the thermoplastic resin of the main component. Extrusion of the coating composition consisting of a thermoplastic resin mixture consisting of 5 to 40% by weight of at least one thermoplastic resin, which is a high minor component, a chemical blowing agent, inorganic particles, and a process aid, onto a substrate (1) running on a cooling roll with a melt extrusion coating machine. It is characterized by coating.

In addition, the breathable waterproof multilayer sheet of the present invention is characterized in that the breathable waterproof layer 2 having amorphous irregular micropores 3 formed on the substrate 1 is formed on the substrate 1.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

First, the present invention is a coating composition composed of a thermoplastic resin mixture, a chemical blowing agent, inorganic particles, and a process aid agent having a different crystallization temperature of 10 ° C. or more from each other on a substrate 1 running on a cooling roll with a melt extrusion coating machine. A breathable waterproof multi-layer sheet is prepared in one step of extrusion coating.

The substrate 1 is a paper, a nonwoven fabric, a synthetic film, a fabric, or the like having a structure of one or more layers.

The thermoplastic resin mixture is composed of 60 to 95% by weight of at least one thermoplastic resin having a relatively low crystallization temperature and 5 to 40% by weight of at least one thermoplastic resin having a crystallization temperature of 10 ° C. or more higher than the thermoplastic resin as the main component. Has a mixed composition.

In the present invention, the reason for using the thermoplastic resin, which is the main component and the thermoplastic resin, which is different from the crystallization temperature by 10 ° C. or more, is that the coating composition which exits the die of the extruder is completely solidified and fixed on the substrate in a film sheet state. This is to cause a micro crack by locally generating a tension difference on the film sheet.

Therefore, when the difference in crystallization temperature between the thermoplastic resin as the main component and the thermoplastic resin is less than 10 ° C and when the content of the thermoplastic resin as the minor component is less than 5% by weight, a local crack is effectively generated on the film sheet to produce fine cracks. Difficult to trigger

On the other hand, when the content of the thermoplastic resin as a secondary component exceeds 40% by weight, phase separation between resins occurs in the melt extrusion process, which is not preferable.

Therefore, the content of the thermoplastic resin as a minor component in the thermoplastic resin mixture is 5 to 40% by weight, more preferably 5 to 30% by weight.

Examples of the thermoplastic resin as the main component and the thermoplastic resin as the minor component include (i) polyolefin resins such as polyethylene, polypropylene, and polystyrene, (ii) polyester resins such as polyethylene terephthalate and polybutylene terephthalate, and (iii) nylon 6 Polyamide resins such as nylon 66, nylon 46, polyacrylic resins such as polyacrylic acid and polyacrylamide, copolymer resins thereof, and the like.

As a more specific example, low-density polypropylene (LDPE, crystallization temperature 102 ° C) alone or a mixture of low-density polypropylene (LDPE) and polyethylene terephthalate (crystallization temperature 189 ° C) is used as the thermoplastic resin as a main component. Polypropylene (crystallization temperature 118 degreeC) can be used as a thermoplastic resin.

The composition ratio of the coating composition is preferably 100 parts by weight of the thermoplastic resin mixture, 0.1 to 10 parts by weight of the chemical foaming agent, 5 to 100 parts by weight of the inorganic particles and 0.1 to 2 parts by weight of the process aid.

The chemical blowing agent includes (i) azodicarbondiamide and derivatives thereof, (ii) aryl, alkylsulfonylhydrazide and derivatives thereof, (iii) toluenesulfonyl semicarbazide, (iii) phenyltetrazole And (iii) at least one compound selected from sodium hydrogencarbonate.

In general, azodicarbondiamide-based compounds are most widely used as chemical foaming agents used in plastics, and the present invention has shown good results.

The chemical foaming agent included in the coating composition generates decomposition gas during the melt extrusion coating process, thereby primarily contributing to the formation of micro-pores, and the micro-pores are fine to allow ventilation and permeation. It may develop into a passageway.

However, it is not easy to control the formation of such micropores and micropaths connected thereto by the chemical foaming agent alone.

As the amount of chemical blowing agent is increased, the number of fine pores increases, but it is more difficult to control the formation of fine pores in the process, and the workability is also drastically reduced.

On the other hand, when the amount of chemical blowing agent used is too small, the formation of micropores is significantly reduced.

Therefore, it is preferable that the usage-amount of a chemical blowing agent is 0.01-10 weight part with respect to 100 weight part of thermoplastic resin mixtures, More preferably, it is 0.1-5 weight part.

As the inorganic particles used in the present invention, talc, titanium dioxide, silica, mica, zeolite, barium sulfate, calcium carbonate and the like can be used.

Since the inorganic filler particles in the composite material are known to act as nuclei when cracks are generated by physical external forces, they can play an important role in the breathable film products which are subjected to the stretching or rolling process according to the prior art. .

However, in the present invention, it can be said that the importance on the formation of micropores is relatively low.

Therefore, the shape of the particles is amorphous or spherical or largely irrelevant.

Since the size of the inorganic particles is present in the lamination process or aggregated by 1 to 5 times larger than the size of the primary particles in the product, if too large, poor workability and adversely affect the product.

In addition, if too small, not only is expensive, but because the size of the micropores formed thereby may be too small, breathability or moisture permeability is poor.

Therefore, it is good to use a thing whose primary average particle diameter is 0.01-2 micrometers.

The type of particle is advantageous in terms of price, talc, calcium carbonate and the like.

The use of inexpensive particles lowers the price of the overall pore-forming composite material, so the more it is used, the more advantageous it is. However, if it is used too much, the processability decreases, so it is better to use 100 parts by weight or less with respect to 100 parts by weight of the maximum thermoplastic resin mixture. .

In the present invention, the importance of the inorganic particles is relatively low, but it is difficult to control the fine pore formation when not used at all.

This is presumably because the inorganic particles play a role in the process of forming micropores by the chemical blowing agent, and it is preferable to use at least 5 parts by weight based on 100 parts by weight of the minimum thermoplastic resin mixture.

As a process aid used in the present invention, (i) a crosslinking agent such as dicumyl peroxide, di-tert-butyl peroxide, dibenzoyl peroxide, and (ii) tetrakis methylene-3di-tert-butyl-4- At least one or more selected from phenol-based or quinone-based or amine-based antioxidants such as hydroxyphenyl propionate methane, and release agents such as (i) waxes and calcium stearylates can be used.

The role of this process aid improves breathability and waterproof lamination processability, and is used as an auxiliary means for controlling the formation of micropores.

When the amount of the chemical blowing agent exceeds 3 parts by weight with respect to 100 parts by weight of the thermoplastic resin mixture, it is better to use a certain amount of the crosslinking agent as a process aid.

In order to increase the formation of fine pores, it is recommended to use an antioxidant together to increase process stability.

When the melt extrusion processability is poor, it is preferable to use a release agent and an antioxidant together with a predetermined amount.

Process aids are not recommended for excessive use because they are not the primary means of forming breathable waterproof laminates.

It is preferable to adjust the formation state and processability of micropores using 0.1-2 weight part with respect to 100 weight part of thermoplastic resin mixtures.

The coating composition prepared as described above may be easily prepared in a pellet state by using a general single screw or twin screw extruder, and may be used to form a breathable waterproof layer.

In the present invention, the breathable waterproof layer 2 is formed on the substrate 1 in one step of general melt extrusion coating, without stretching, rolling, elution, or other chemical or mechanical treatment.

An extrusion coating machine used in the present invention is composed of an apparatus for melting and extruding a material, a cooling roll, and an apparatus for running and winding a sheet.

In order to better process processability, it is preferable that a vent line is installed at the melt extruder part, and the detention should have a hanger shape rather than a flat shape.

Moreover, it is good that the surface of a cooling roll is mirror-processed, Teflon treatment, etc.

The breathable waterproof multi-layered sheet of the present invention made in this way is not stretched in the traveling direction or the machine direction of the sheet, and since no other physical external force or chemical treatment is applied to the sheet after lamination has occurred, The shape of the fine pores formed in the irregular shape and there is no arrangement or direction of the formed pores.

In the case of the breathable film according to the prior art, it can be said that the pores formed due to stretching, rolling, and the like have a certain orientation or arrangement, so that the breathable waterproof multilayer sheet of the present invention has a different microstructure (Morphology) from these products. can do.

It is unclear at this time whether these differences can be correlated with characteristics such as product breathability.

However, if a functional material in the form of an organic compound or a low molecular weight polymer is added to impart a second function to the breathable waterproof layer to be laminated, due to this difference, in the multilayer sheet of the present invention, these materials are transferred to the sheet surface. It has a big advantage that can prevent).

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

The method of physical property evaluation and analysis in an Example and a comparative example is as follows.

Crystallization Temperature

Using a differential scanning thermal analyzer (DSC-7 from Perkin-Elmer, Inc.), the thermoplastic resin sample was heated to 300 ° C. for 1 minute, and then cooled at 20 ° C./min while cooling at 20 ° C./min. ℃) was measured.

Moisture permeability

According to the method of ASTM E96-92 was measured and calculated the moisture permeability (g / m 2 ~ 24Hrs) with increasing weight after a certain time.

Pore Formability

Using a scanning electron microscope (SEM, Hitachi Co., Ltd.), three or more locations of the breathable waterproof laminated surface were selected to observe the pore formation state. The number of pores whose diameter (average of long and short diameters in the case of an ellipse) formed in an area of 0.1 mm x 0.1 mm on a laminated surface was 0.1-20 micrometers was counted, and it determined as follows.

○ (excellent): When the pore-forming state is good and there are 20 or more.

△ (normal): 10 to 20 pores.

× (Poor): When the number of pores is 10 or less, or the form of the pores is too small or large.

Fairness

The state of extrusion and lamination, the traveling speed of the sheet, and the like were observed and determined as follows.

○ (good): When the extrusion and lamination operations proceed satisfactorily for a long time and the sheet traveling speed is 40 m / min or more.

X (Poor): When work interruption occurs three times or more per hour due to poor extrusion, die wiping, lamination unevenness in the width direction, gripping, or when the sheet traveling speed is 40 m / min or less.

·Exterior

The nonuniformity, touch, etc. of the breathable waterproof laminated surface were observed.

Example 1

80% by weight of low density polyethylene (LDPE, Hanwha Chemical) having a crystallization temperature of 102 ° C, a melting point of 115 ° C, a MI of 5, a polypropylene having a crystallization temperature of 118 ° C, a melting point of 160 ° C, and a MI of 10; PP, Korea emulsified product) 5.0 parts by weight of azodicarbondiamide (chemical blowing agent), 35 parts by weight of calcium carbonate (inorganic particles) having an average particle diameter of 100 parts by weight of a thermoplastic resin mixture consisting of 20% by weight of DQ and a process aid 0.2 parts by weight of Milper oxide and 0.2 parts by weight of calcium stearylate were added to prepare a coating composition.

The coating composition was extrusion-coated on a polypropylene nonwoven fabric (substrate) running on a chill roll at a speed of 100 m / min with a melt extrusion coating to prepare a breathable waterproof multilayer sheet.

As the melt extrusion coating machine, a straight T-die of 2,000 mm, a uniaxial extrusion part of 90Φ, a Teflon-treated cooling roll, and a sheet traveling device were used.

On the other hand, as the polypropylene nonwoven fabric (substrate), a weight per unit area of 30 g / m 2, a width of 1,800 m, and a single yarn diameter of 3 denier were used.

The results of evaluating the physical properties of the manufactured breathable waterproof multilayer sheet are shown in Table 1.

In addition, the photograph measured by the electron microscope of the cross-sectional state of the breathable waterproof layer 2 which comprises the manufactured breathable waterproof multilayer sheet is as FIG. 2, and the photograph measured by the electron microscope is a surface state as FIG.

2 and 3 are a plurality of amorphous micropores are not directional, irregular, irregular in size.

Example 2

75% by weight of low density polyethylene (LDPE, Hanwha Chemical) having a crystallization temperature of 102 ° C, a melting point of 115 ° C, a MI of 5, a polypropylene having a crystallization temperature of 118 ° C, a melting point of 160 ° C, and a MI of 10 100 parts by weight of a thermoplastic resin mixture consisting of 20% by weight of PP, a Korean emulsified product, and 5% by weight of a polyethylene terephthalate (PET, Kolon Co., Ltd.) having a crystallization temperature of 189 ° C., a melting point of 256 ° C., and a MI of 10. 1.0 parts by weight of dicarbondiamide (chemical blowing agent), 40 parts by weight of calcium carbonate (inorganic particles) having an average particle diameter of 1 μm, and 0.2 parts by weight of Iganox 1010 and 0.3 parts by weight of calcium stearylate as process aids were added. Prepared.

The coating composition was extrusion-coated on a polypropylene nonwoven fabric (substrate) running on a chill roll at a speed of 100 m / min with a melt extrusion coating to prepare a breathable waterproof multilayer sheet.

As the melt extrusion coating machine, a straight T-die of 2,000 mm, a uniaxial extrusion part of 90Φ, a Teflon-treated cooling roll, and a sheet traveling device were used.

On the other hand, as the polypropylene nonwoven fabric (substrate), a weight per unit area of 30 g / m 2, a width of 1,800 m, and a single yarn diameter of 3 denier were used.

The results of evaluating the physical properties of the manufactured breathable waterproof multilayer sheet are shown in Table 1.

Example 3

70% by weight of low density polyethylene (LDPE, Hanwha Chemical) having a crystallization temperature of 102 ° C, a melting point of 115 ° C, a MI of 5, a polypropylene having a crystallization temperature of 118 ° C, a melting point of 160 ° C, and a MI of 10 PP, Korea Emulsified Products) 2.0 parts by weight of azodicarbondiamide (chemical blowing agent), 20 parts by weight of calcium carbonate (inorganic particles) having an average particle diameter of 100 parts by weight of a thermoplastic resin mixture consisting of 30% by weight of divalent and a process aid 0.1 parts by weight of Knox 1010 was added to prepare a coating composition.

The coating composition was extrusion-coated on a polypropylene nonwoven fabric (substrate) running on a chill roll at a speed of 100 m / min with a melt extrusion coating to prepare a breathable waterproof multilayer sheet.

As the melt extrusion coating machine, a straight T-die of 2,000 mm, a uniaxial extrusion part of 90Φ, a Teflon-treated cooling roll, and a sheet traveling device were used.

On the other hand, as the polypropylene nonwoven fabric (substrate), a weight per unit area of 30 g / m 2, a width of 1,800 m, and a single yarn diameter of 3 denier were used.

The results of evaluating the physical properties of the manufactured breathable waterproof multilayer sheet are shown in Table 1.

Example 4

60% by weight of low density polyethylene (LDPE, Hanwha Chemical) having a crystallization temperature of 102 ° C, a melting point of 115 ° C, a MI of 5, a polypropylene having a crystallization temperature of 118 ° C, a melting point of 160 ° C, and a MI of 10 100 parts by weight of azodicarbondiamide (chemical blowing agent), 100 parts by weight of calcium carbonate (inorganic particles) having an average particle diameter of 100 parts by weight of 100 parts by weight of a thermoplastic resin mixture composed of 40% by weight of PP, and a process aid. 0.5 parts by weight of stearylate was added to prepare a coating composition.

The coating composition was extrusion-coated on a polypropylene nonwoven fabric (substrate) running on a chill roll at a speed of 100 m / min with a melt extrusion coating to prepare a breathable waterproof multilayer sheet.

As the melt extrusion coating machine, a straight T-die of 2,000 mm, a uniaxial extrusion part of 90Φ, a Teflon-treated cooling roll, and a sheet traveling device were used.

On the other hand, as the polypropylene nonwoven fabric (substrate), a weight per unit area of 30 g / m 2, a width of 1,800 m, and a single yarn diameter of 3 denier were used.

The results of evaluating the physical properties of the manufactured breathable waterproof multilayer sheet are shown in Table 1.

Example 5

Polyethylene terephthalate having a crystallization temperature of 102 ° C, a melting point of 115 ° C, 95% by weight of low density polyethylene (LDPE, Hanwha Chemical) having a MI of 5, a crystallization temperature of 189 ° C, a melting point of 265 ° C, and a MI of 10 10 parts by weight of azodicarbondiamide (chemical blowing agent), 5 parts by weight of calcium carbonate (inorganic particles) having an average particle diameter of 100 parts by weight to 100 parts by weight of a thermoplastic resin mixture composed of 5% by weight, and a process aid 0.8 parts by weight of dicumyl peroxide, 0.5 parts by weight of Iganox 1010 and 0.5 parts by weight of calcium stearylate were added to prepare a coating composition.

The coating composition was extrusion-coated on a polypropylene nonwoven fabric (substrate) running on a chill roll at a speed of 100 m / min with a melt extrusion coating to prepare a breathable waterproof multilayer sheet.

As the melt extrusion coating machine, a straight T-die of 2,000 mm, a uniaxial extrusion part of 90Φ, a Teflon-treated cooling roll, and a sheet traveling device were used.

On the other hand, as the polypropylene nonwoven fabric (substrate), a weight per unit area of 30 g / m 2, a width of 1,800 m, and a single yarn diameter of 3 denier were used.

The results of evaluating the physical properties of the manufactured breathable waterproof multilayer sheet are shown in Table 1.

Comparative Example 1

Calcium carbonate with a crystallization temperature of 102 ° C, melting point of 115 ° C, 100 parts by weight of low density polyethylene (LDPE, Hanwha Chemical) 10 parts by weight of azodicarbondiamide (chemical blowing agent) and an average particle diameter of 1 μm (Inorganic particles) 5 parts by weight, 0.6 parts by weight of dicumyl peroxide, 0.5 parts by weight of Iganox 1010 and 0.5 parts by weight of calcium stearylate were added as a process aid to prepare a coating composition.

The coating composition was extrusion-coated on a polypropylene nonwoven fabric (substrate) running on a chill roll at a speed of 100 m / min with a melt extrusion coating to prepare a breathable waterproof multilayer sheet.

As the melt extrusion coating machine, a straight T-die of 2,000 mm, a uniaxial extrusion part of 90Φ, a Teflon-treated cooling roll, and a sheet traveling device were used.

On the other hand, as the polypropylene nonwoven fabric (substrate), a weight per unit area of 30 g / m 2, a width of 1,800 m, and a single yarn diameter of 3 denier were used.

The results of evaluating the physical properties of the manufactured breathable waterproof multilayer sheet are shown in Table 1.

Comparative Example 2

70% by weight of a low density polyethylene (LDPE, Hanwha Chemical) having a crystallization temperature of 102 ° C, a melting point of 115 ° C, a MI of 5, a high density polyethylene having a crystallization temperature of 110 ° C, a melting point of 135 ° C, and a MI of 8 HDPE, Korea Emulsified Products) 5.0 parts by weight of azodicarbondiamide (chemical blowing agent), 35 parts by weight of calcium carbonate (inorganic particles) having an average particle diameter of 100 parts by weight of a thermoplastic resin mixture composed of 30% by weight of DQ and a process aid 0.2 parts by weight of Milper oxide and 0.2 parts by weight of calcium stearylate were added to prepare a coating composition.

The coating composition was extrusion-coated on a polypropylene nonwoven fabric (substrate) running on a chill roll at a speed of 100 m / min with a melt extrusion coating to prepare a breathable waterproof multilayer sheet.

As the melt extrusion coating machine, a straight T-die of 2,000 mm, a uniaxial extrusion part of 90Φ, a Teflon-treated cooling roll, and a sheet traveling device were used.

On the other hand, as the polypropylene nonwoven fabric (substrate), a weight per unit area of 30 g / m 2, a width of 1,800 m, and a single yarn diameter of 3 denier were used.

The results of evaluating the physical properties of the manufactured breathable waterproof multilayer sheet are shown in Table 1.

Property evaluation result Water vapor permeability (g / ㎡, 24Hrs) Pore Formability Fairness Exterior Example 1 8,750 ○ ○ Good Example 2 5,210 ○ ○ Good Example 3 6,500 ○ ○ Good Example 4 4,160 ○ ○ Good Example 5 4,940 ○ ○ Good Comparative Example 1 1,820 △ × Non-uniformity Comparative Example 2 1,600 △ ○ Good

According to the present invention, the manufacturing process of the breathable waterproof multi-layer sheet is simplified, so that quality control is easy and manufacturing cost is reduced, and expensive facility introduction is unnecessary.

Therefore, there is an effect that can impart a waterproof waterproof function to a variety of materials (substrate) in various fields, such as building materials, which was difficult to apply due to the conventional cost.

1 is a schematic cross-sectional view of a breathable waterproof multilayer sheet according to the present invention.

Figure 2 is an electron micrograph showing a cross-sectional state of the breathable waterproof layer (2) constituting the present invention.

3 is an electron micrograph showing the surface state of the breathable waterproof layer 2 of the present invention.

* Explanation of symbols on the main parts of the drawings

1: Base material (layer) 2: Breathable waterproof layer

3: fine pores

Claims (8)

A thermoplastic resin mixture comprising 60 to 95% by weight of one or more thermoplastic resins having a relatively low crystallization temperature and 5 to 40% by weight of one or more thermoplastic resins having a crystallization temperature of 10 ° C. or more higher than the thermoplastic resin as a main component, A method for producing a breathable waterproof multilayer sheet, characterized in that the coating composition consisting of a chemical blowing agent, inorganic particles and a process aid is extrusion coated on a substrate (1) running on a cooling roll with a melt extrusion coating. The method for producing a breathable waterproof multilayer sheet according to claim 1, wherein the substrate (1) is one selected from paper, nonwoven fabric, synthetic film, and fabric having a structure of one or more layers. The breathable waterproof multilayer sheet according to claim 1, wherein the coating resin composition is composed of 100 parts by weight of a thermoplastic resin mixture, 0.01 to 10 parts by weight of a chemical foaming agent, 5 to 100 parts by weight of inorganic particles, and 0.1 to 2 parts by weight of a process aid. Manufacturing method. The breathable waterproof multilayer sheet according to claim 1, wherein each of the primary and secondary thermoplastic resins is one resin selected from polyolefin resins, polyacrylic resins, polyester resins, polyamide resins, and copolymerized resins thereof. Manufacturing method. The chemical blowing agent according to claim 1, wherein the chemical blowing agent is selected from (i) azodicarbondiamide and derivatives thereof, (ii) aryl, alkylsulfonylhydrazide and derivatives thereof, (iii) toluenesulfonyl semicarbazide, (iii) phenyltetrazole and (Iii) A method for producing a breathable waterproof multilayer sheet, characterized in that at least one compound selected from sodium hydrogencarbonate. The method for producing a breathable waterproof multilayer sheet according to claim 1, wherein the inorganic particles are at least one particle selected from talc, titanium dioxide, silica, mica, zeolite, barium sulfate and calcium carbonate. The method for producing a breathable waterproof multilayer sheet according to claim 1, wherein the processing aid is at least one compound selected from a crosslinking agent, an antioxidant and a release agent. A breathable waterproof multilayer sheet, characterized in that the breathable waterproof layer (2) having amorphous irregular micropores (3) is formed on the substrate (1) by the manufacturing method of claim 1.