A primer-free one-shot molding water-based adhesive as well as a preparation method and application thereof

Abstract

This invention belongs to the field of fabric coating technology, and relates to a base-free, one-cut water-based adhesive, its preparation method, and its application. The raw materials of the base-free, one-cut water-based adhesive include specific weight parts of water-based polyurethane resin, film-forming aid, water-based epoxy silane coupling agent, and fumed silica aqueous solution. Through the reasonable combination of the above components, the resulting water-based adhesive is in a high shear rheological state with a slight overlap with the blade, making it easier to apply and maximizing the amount of adhesive applied in one cut and film formation. It also ensures that the adhesive layer formed after one-cut molding has ultra-high hydrostatic pressure. At the same time, the base-free, one-cut water-based adhesive is suitable for different types of base fabrics and has an effect comparable to oil-based adhesive coatings for all base fabrics. The coated fabric produced has excellent adhesion, excellent crease resistance, excellent scratch resistance, good water resistance, and does not turn white when soaked in water.

Description

Technical Field

[0001] This invention belongs to the field of fabric coating technology, and relates to a primer-free, one-cut water-based adhesive, its preparation method, and its application. Background Technology

[0002] As people's understanding of environmental protection deepens, green and sustainable production and consumption patterns have become a global consensus and development trend, making the reduction of VOC emissions a top priority. For the textile industry, the pace of replacing oil-based adhesives with water-based adhesives is also accelerating.

[0003] Currently, a large portion of ordinary oil-based adhesives have been replaced by water-based adhesives. However, for some higher-requirement applications, such as ultra-high water pressure resistance, water washability, and strong film-like texture, oil-based adhesives are still the primary choice, as water-based technology cannot achieve the functional effects of oil-based adhesives. For example, CN104611933A discloses a method for preparing a high hydrostatic pressure resistant water-based polyurethane fabric coating agent. The synthesized water-based polyurethane emulsion has good storage stability and, when applied to fabric finishing, provides a good hand feel, good adhesion, is non-toxic, environmentally friendly, and easy to operate. When applied to polyester spinning, its hydrostatic pressure resistance value is in the range of 100~150 kPa. However, this invention does not mention the amount of adhesive applied per square meter, while the amount of adhesive applied directly affects the water pressure. Another example is CN102418274A, which discloses a method for preparing a high hydrostatic pressure resistant anionic water-based polyurethane coating agent. The obtained product has high adhesion strength and is applied to fabric finishing, providing a good hand feel, is safe and non-toxic, environmentally friendly, and the process is simple to operate. Its hydrostatic pressure resistance and soap washing fastness have reached the level of imported high-grade water-based PU fabric coating agents; the invention also does not mention the specific amount of adhesive applied per square meter.

[0004] In addition, most other existing technologies focus more on the particle size, viscosity, hydrophobicity, polymerization method, film strength and high and low temperature stability of the emulsion, without involving the study of the following effect. The stronger the following effect, the thicker the coating film, the easier it is to apply adhesive, and the easier it is to achieve high water pressure in one cut.

[0005] Therefore, developing a water-based adhesive that requires no primer, has high water pressure resistance, and is universally applicable, remains an urgent technical problem to be solved in this field. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a base-free, one-cut water-based adhesive, its preparation method, and its application. This base-free, one-cut water-based adhesive overcomes the limitations of existing technologies in terms of substrate selectivity, achieving high water pressure requirements that meet or even exceed those of oil-based adhesives for almost all substrates, and enabling one-cut application, thus fundamentally breaking through the technical bottleneck.

[0007] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a base-free, one-cut water-based adhesive, wherein the raw materials of the base-free, one-cut water-based adhesive comprise the following components by weight: 75-85 parts by weight of waterborne polyurethane resin; 1-3 parts by weight of film-forming aid; 0.2-1 parts by weight of waterborne epoxy silane coupling agent; 0.2 to 1 part by weight of fumed silica aqueous solution.

[0008] The raw materials for the primerless, one-cut water-based adhesive provided by this invention include specific weight parts of water-based polyurethane resin, film-forming aid, water-based epoxy silane coupling agent, and fumed silica aqueous solution. By selecting water-based polyurethane resin as the base resin and combining it with film-forming aid and other additives, particularly by effectively combining the fumed silica aqueous solution with the water-based epoxy silane coupling agent, the fumed silica in the aqueous solution has a high specific surface area, effectively improving the strength of the adhesive film. The water-based epoxy silane coupling agent can be used in the water-based system for a long time. (At least 6 months) Stable coexistence, effectively improving the water resistance and weather resistance of the adhesive film. Through the reasonable combination of the above components, the resulting water-based adhesive is in a viscous, high-shear rheological state with some cutting edge, which is very close to the state of oil-based polyurethane, making it easier to apply. This maximizes the amount of adhesive and film formation of the one-cut coating, ensuring that the formed adhesive layer can achieve the effect of ultra-high hydrostatic pressure. It is also universally applicable to different types of fabrics, such as long-filament Oxford cloth, elastic Oxford cloth, polyester taffeta, spring spun, nylon taffeta, air-textured yarn, and cotton base fabrics.

[0009] In addition, the water-based adhesive provided by this invention, which requires no base coat and can be formed in one cut, has excellent bonding performance, high film strength, excellent crease resistance (resistant to hand scratches without white marks), excellent scratch resistance, good water resistance, and does not turn white when soaked in water. It is also free of formaldehyde and DMF, making it very environmentally friendly.

[0010] The waterborne polyurethane resin may be present in weight proportions of 75 parts by weight, 76 parts by weight, 77 parts by weight, 78 parts by weight, 79 parts by weight, 80 parts by weight, 81 parts by weight, 82 parts by weight, 83 parts by weight, 84 parts by weight, or 85 parts by weight.

[0011] The weight ratio of the film-forming aid can be 1 part by weight, 1.2 parts by weight, 1.4 parts by weight, 1.6 parts by weight, 1.8 parts by weight, 2 parts by weight, 2.2 parts by weight, 2.4 parts by weight, 2.6 parts by weight, 2.8 parts by weight, or 3 parts by weight, etc.

[0012] The weight ratio of the aqueous epoxy silane coupling agent can be 0.2 parts by weight, 0.3 parts by weight, 0.4 parts by weight, 0.5 parts by weight, 0.6 parts by weight, 0.7 parts by weight, 0.8 parts by weight, 0.9 parts by weight, or 1 part by weight.

[0013] The weight ratio of the fumed silica aqueous solution can be 0.2 parts by weight, 0.3 parts by weight, 0.4 parts by weight, 0.5 parts by weight, 0.6 parts by weight, 0.7 parts by weight, 0.8 parts by weight, 0.9 parts by weight, or 1 part by weight, etc.

[0014] Preferably, the waterborne polyurethane resin includes polyether-type waterborne polyurethane resin and / or polyester-type waterborne polyurethane resin.

[0015] Preferably, the modulus of the waterborne polyurethane resin is 0.5~2.5 MPa, such as 0.5 MPa, 0.7 MPa, 0.9 MPa, 1.1 MPa, 1.3 MPa, 1.5 MPa, 1.7 MPa, 1.9 MPa, 2.1 MPa, 2.3 MPa or 2.5 MPa.

[0016] Preferably, the elongation at break of the waterborne polyurethane resin is 1000~1800%, such as 1000%, 1100%, 1200%, 1300%, 1400%, 1500%, 1600%, 1700% or 1800%.

[0017] Preferably, the waterborne polyurethane resin includes any one or a combination of at least two of IPDI type polyurethane resin, MDI type polyurethane resin, TDI type polyurethane resin or HDI type polyurethane resin.

[0018] Preferably, the film-forming aid comprises dodecyl alcohol ester.

[0019] Preferably, the mass percentage of fumed silica in the fumed silica aqueous solution is 5-10%, such as 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5% or 10%.

[0020] Preferably, the specific surface area of ​​the fumed silica in the aqueous fumed silica solution is 190~250 m². 2 / g, for example, 190 m 2 / g、200 m 2 / g、210 m 2 / g、220 m 2 / g、230 m 2 / g、240 m 2 / g or 250 m 2 / g etc.

[0021] Preferably, the raw materials of the primer-free, one-cut water-based adhesive also include other additives.

[0022] Preferably, the weight ratio of other additives in the raw materials of the primer-free one-cut water-based adhesive is 4 to 20 parts by weight, such as 4 parts by weight, 6 parts by weight, 8 parts by weight, 10 parts by weight, 12 parts by weight, 14 parts by weight, 16 parts by weight, 18 parts by weight, or 20 parts by weight.

[0023] Preferably, the other additives include any one or a combination of at least two of the following: thickeners, defoamers, wetting agents, leveling agents, adhesion promoters, or bactericides.

[0024] In a second aspect, the present invention provides a method for preparing a base-free, one-cut waterborne adhesive as described in the first aspect. The preparation method includes: mixing a waterborne polyurethane resin and a film-forming aid, adding a waterborne epoxy silane coupling agent and mixing, and then adding a fumed silica aqueous solution and mixing to obtain the base-free, one-cut waterborne adhesive.

[0025] Preferably, after the addition of the fumed silica aqueous solution for mixing is completed, the process further includes the addition of other additives for mixing.

[0026] Preferably, the preparation method includes: first, adding waterborne polyurethane resin to a reaction vessel, and stirring at a speed of 80-100 rpm (e.g., 80 rpm, 82 rpm, 84 rpm, 86 rpm, 88 rpm, 90 rpm, 92 rpm, 94 rpm, 96 rpm, 98 rpm, or 100 rpm, etc.) for 3-5 min (e.g., 3 min, 3.2 min, 3.4 min, 3.6 min, 3.8 min, 4 min, 4.2 min, 4.4 min, 4.6 min, 4.8 min, or 5 min, etc.) while stirring. Simultaneously, adding 40-60% (e.g., 40%, 42%, 44%, 46%, 48%, 50%, 52%, 54%, 56%, 58%, or 60%, etc.) of film-forming aids by mass of the total film-forming aids, and continuing stirring for 5-15 min (e.g., 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, 12 min, 14 min, or 15 min, etc.) Then add the remaining film-forming aids, which account for 40-60% of the total mass of the film-forming aids (e.g., 40%, 42%, 44%, 46%, 48%, 50%, 52%, 54%, 56%, 58%, or 60%, etc.), and continue stirring for 5-15 minutes (e.g., 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, 12 min, 14 min, or 15 min, etc.). Next, slowly add the aqueous epoxy silane coupling agent to the reactor and continue stirring for 5-15 minutes (e.g., 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, 12 min, 14 min, or 15 min, etc.). Then, slowly add the fumed silica aqueous solution to the reactor and continue stirring for 5-15 minutes (e.g., 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, 12 min, 14 min, or 15 min, etc.). Finally, slowly add the remaining aids to the reactor and continue stirring for 50-60 minutes (e.g., 50 min, 51 min, etc.). (e.g., 52 min, 53 min, 54 min, 56 min, 58 min, or 60 min) to obtain the base-free, one-cut water-based adhesive.

[0027] Thirdly, the present invention provides a high water pressure resistant coated fabric, the high water pressure resistant coated fabric comprising a base fabric A and an aqueous adhesive layer attached to one side surface of the base fabric A; The water-based adhesive layer is formed by applying and drying the water-based adhesive as described in the first aspect, without the need for a primer.

[0028] It should be noted that the "high water pressure resistant coated fabric" mentioned in this invention refers to a coated fabric that can withstand hydrostatic pressure ≥100000 Pa.

[0029] Preferably, the base fabric A includes any one of Oxford cloth, polyester taffeta, polyester fabric, cotton fabric, spring spun or nylon spun.

[0030] Preferably, the amount of adhesive applied in one pass is 10~50 g / m (dry weight). 2 For example, 10 g / m 2 11 g / m 2 12 g / m 2 13 g / m 2 14 g / m 2 15 g / m 2 16 g / m 2 17 g / m 2 18 g / m 2 19 g / m 2 20 g / m 2 25 g / m 2 30 g / m 2 35 g / m 2 40 g / m 2 45 g / m 2 Or 50 g / m 2 wait.

[0031] Preferably, the drying is carried out in an oven.

[0032] Preferably, the drying temperature is 100~200℃, such as 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, 160℃, 170℃, 180℃, 190℃ or 200℃.

[0033] Preferably, the drying time is 0.5 to 5 min, for example 0.5 min, 1 min, 1.5 min, 2 min, 2.5 min, 3 min, 3.5 min, 4 min, 4.5 min or 5 min.

[0034] Preferably, the hydrostatic pressure resistant to high water pressure is ≥100,000 Pa, such as 100,000 Pa, 110,000 Pa, 120,000 Pa, 130,000 Pa, 140,000 Pa, 150,000 Pa, 160,000 Pa, 170,000 Pa, 190,000 Pa, 210,000 Pa, 230,000 Pa, 250,000 Pa, 270,000 Pa, or 290,000 Pa.

[0035] The water-based adhesive provided by this invention provides coating effects comparable to oil-based adhesives on almost all types of substrates, while offering significantly better cost-effectiveness and environmental friendliness. Furthermore, it is easy to apply, with a single application yielding 10-50 g / m² (dry weight). 2 It can withstand ultra-high hydrostatic pressure of ≥100,000 Pa. At the same time, the resulting coated fabric also has excellent water resistance, crease resistance and scratch resistance, and can also resist a certain degree of color migration. It can be used as a fabric with high water pressure requirements such as tent fabric, protective clothing, down jacket lining fabric, umbrella fabric and bag fabric.

[0036] Fourthly, the present invention provides a water-based synthetic leather, which is obtained by first applying a film or hot-pressing a base fabric B, then coating the surface with a water-based adhesive as described in the first aspect (no base coat required for one-cut molding), and then performing texturing or embossing treatment.

[0037] Preferably, the base fabric B includes any one of suede, spring spun, nylon spun, or voile.

[0038] Preferably, the amount of dry adhesive applied is 50~300 g / m². 2 For example, 50 g / m 2 70 g / m 2 90 g / m 2 110 g / m 2 130 g / m 2 150 g / m 2 170 g / m 2 190 g / m 2 210 g / m 2 230 g / m 2 250 g / m 2 270 g / m 2 Or 300g / m 2 wait.

[0039] Compared with the prior art, the present invention has the following beneficial effects: (1) The water-based adhesive for one-cut molding without primer provided by the present invention has a high amount of adhesive applied in one cut and excellent film-forming properties. When using it, there is no need to apply a primer to the base fabric. It can be molded in one cut and can reach an ultra-high hydrostatic pressure of ≥100,000 Pa. Specifically, when applied to 600D elastic Oxford cloth for tents, the hydrostatic pressure of one-cut molding can reach more than 200,000 Pa. When applied to polyester cloth, spring spun or nylon spun, the hydrostatic pressure of one-cut molding can reach 100,000~300,000 Pa. (2) The water-based adhesive provided by the present invention has a wide range of applications. It has an effect comparable to oil-based adhesive coating on almost all fabrics and coated fabrics. It is formaldehyde-free and DMF-free, and its cost-effectiveness and environmental friendliness are far superior to oil-based adhesives. (3) The coated fabrics and water-based synthetic leather made with the water-based adhesive provided by the present invention have the advantages of good adhesion, excellent crease resistance (resistance to hand scratch white marks), high adhesion, resistance to a certain degree of color migration, high film strength, excellent scratch resistance and good water resistance, and no whitening when soaked in water. Detailed Implementation

[0040] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0041] The following examples and comparative examples involve detailed information on some of the raw materials: (1) Waterborne polyurethane resin: with a modulus of 1 MPa and an elongation at break of 1300%, specifically a polyether-type waterborne polyurethane resin, purchased from Wanhua Chemical, brand name Leasys 3483. (2) Waterborne epoxy silane coupling agent: specifically, geopolysiloxane, purchased from Nanjing Quanxi Chemical Co., Ltd., brand name QX-2926.

[0042] Preparation Example 1 An aqueous solution of fumed silica, comprising fumed silica (specific surface area of ​​190~250 m²) 2 The mass percentage content of ( / g) is 7%; The preparation method includes: adding 70 parts by weight of fumed silica to 930 parts by weight of water at room temperature, soaking for 24 h, and then stirring at 60 rpm for 2 h to obtain the fumed silica aqueous solution.

[0043] Preparation Example 2 An aqueous solution of fumed silica, comprising fumed silica (specific surface area of ​​190~250 m²) 2 The mass percentage of ( / g) is 9%; The preparation method includes: adding 90 parts by weight of fumed silica to 910 parts by weight of water at room temperature, soaking for 24 h, and then stirring at 60 rpm for 2 h to obtain the fumed silica aqueous solution.

[0044] Preparation Example 3 An aqueous solution of fumed silica, comprising fumed silica (specific surface area of ​​190~250 m²) 2 The mass percentage of ( / g) is 3%; The preparation method includes: adding 30 parts by weight of fumed silica to 970 parts by weight of water at room temperature, soaking for 24 h, and then stirring at 60 rpm for 2 h to obtain the fumed silica aqueous solution.

[0045] Examples 1-5 and Comparative Examples 1-5 Examples 1-5 and Comparative Examples 1-5 each provide a base-free, one-cut water-based adhesive. The components and amounts contained therein are shown in Table 1. In Table 1, the unit for each component is "parts by weight". Table 1 The preparation methods of the primer-free, one-cut water-based adhesives provided in Examples 1-5 and Comparative Examples 1-5 include the following steps: First, add waterborne polyurethane resin to the reactor and stir at 100 rpm for 5 minutes. While stirring, add 50% of the film-forming aid by mass and continue stirring for 10 minutes. Then add the remaining 50% of the film-forming aid and continue stirring for 10 minutes. Next, slowly add the waterborne epoxy silane coupling agent to the reactor and continue stirring for 10 minutes. Then, slowly add the fumed silica aqueous solution to the reactor and continue stirring for 10 minutes to obtain the primer-free, one-cut waterborne adhesive.

[0046] Performance testing: Mix 100 parts by weight of a primerless, one-cut water-based adhesive, 2 parts by weight of a thickener (specifically, a water-based polyurethane thickener, purchased from Wanhua Chemical, brand name A801), and 1 part by weight of a curing agent (purchased from Guangdong Sloco Polymer Co., Ltd., brand name water-based additive 1099) thoroughly, and then mix according to a dry weight of 15 g / m 2 The amount of adhesive applied was determined, and it was applied in one stroke to the surface of 72 waterproof calendered Oxford cloth with 600D elastic yarn. The application speed was 30-40 yards, and then it was dried at 100-200℃ for 3 minutes to form an adhesive film coating. After obtaining the coated fabric, the following tests were performed: (1) Hydrostatic pressure: The hydrostatic pressure was obtained by using a YG825E digital permeability tester (Ningbo Textile Instrument Factory).

[0047] (2) Whitening resistance: Soak the film in water at 25℃ for 24 hours and observe whether it turns white.

[0048] (3) Crease resistance: Hold the adhesive film by hand and observe whether creases will appear.

[0049] ① The water-based adhesives provided in Examples 1-5 and Comparative Examples 1-5, which require no primer and can be applied in one pass, were tested according to the above test methods. The test results are shown in Table 2: Table 2 According to the data in Table 2: The coated fabrics obtained by the one-cut water-based adhesive without primer provided in Examples 1 to 5 all have high hydrostatic pressure (≥16000 Pa), and also have excellent water whitening resistance and crease resistance. In contrast, the hydrostatic pressure of the water-based adhesive provided in Comparative Examples 1 to 5 is lower, and the strength of the coated fabrics obtained by the water-based adhesive provided in Comparative Examples 4 to 5 is lower.

[0050] ② Next, mix 100 parts by weight of the primer-free, one-cut water-based adhesive provided in Example 1, 2 parts by weight of thickener (specifically, a water-based polyurethane thickener, purchased from Wanhua Chemical, brand name A801), and 1 part by weight of curing agent (purchased from Guangdong Sloco Polymer Co., Ltd., brand name water-based additive 1099) evenly, and then mix according to a dry weight of 20 g / m 2 The amount of adhesive applied was measured and applied in one stroke to the surface of 1×1 waterproof lightly rolled Oxford cloth. The construction speed was 60 yards, and the coating was formed after drying at 100~200℃ for 5 minutes. After obtaining the coated fabric, the hydrostatic pressure of the coating was tested according to the above test method and found to be 200000 Pa. The adhesive film did not turn white after being soaked in water at 25℃ for 24 hours, and no white marks appeared when the adhesive film was touched.

[0051] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A water-based adhesive that requires no base coat and can be applied in one pass, characterized in that, The raw materials of the primer-free, one-cut water-based adhesive include the following components by weight: 75-85 parts by weight of waterborne polyurethane resin; 1-3 parts by weight of film-forming aid; 0.2-1 parts by weight of waterborne epoxy silane coupling agent; 0.2 to 1 part by weight of fumed silica aqueous solution.

2. The water-based adhesive for one-cut molding without primer according to claim 1, characterized in that, The waterborne polyurethane resin includes polyether-type waterborne polyurethane resin and / or polyester-type waterborne polyurethane resin. Preferably, the modulus of the waterborne polyurethane resin is 0.5~2.5 MPa; Preferably, the elongation at break of the waterborne polyurethane resin is 1000~1800%; Preferably, the waterborne polyurethane resin includes any one or a combination of at least two of IPDI type polyurethane resin, MDI type polyurethane resin, TDI type polyurethane resin or HDI type polyurethane resin.

3. The water-based adhesive for one-cut molding without primer according to claim 1 or 2, characterized in that, The film-forming aid includes dodecyl alcohol ester; Preferably, the mass percentage of fumed silica in the fumed silica aqueous solution is 5-10%; Preferably, the specific surface area of ​​the fumed silica in the aqueous fumed silica solution is 190~250 m². 2 / g.

4. The water-based adhesive for one-cut molding without primer according to any one of claims 1 to 3, characterized in that, The raw materials of the water-based adhesive that requires no base coat and can be formed in one cut also include other additives; Preferably, the content of other additives in the raw materials of the primer-free one-cut water-based adhesive is 4 to 20 parts by weight; Preferably, the other additives include any one or a combination of at least two of the following: thickeners, defoamers, wetting agents, leveling agents, adhesion promoters, or bactericides.

5. A method for preparing a water-based adhesive that requires no primer and can be applied in one pass as described in any one of claims 1 to 4, characterized in that, The preparation method includes: mixing waterborne polyurethane resin and film-forming aid, adding waterborne epoxy silane coupling agent and mixing, and then adding fumed silica aqueous solution and mixing to obtain the primer-free one-cut waterborne adhesive. Preferably, after the addition of the fumed silica aqueous solution for mixing is completed, the process further includes the addition of other additives for mixing.

6. A high-water-pressure resistant coated fabric, characterized in that, The high water pressure resistant coated fabric includes a base fabric A and an aqueous adhesive layer attached to one side surface of the base fabric A; The water-based adhesive layer is formed by applying and drying the water-based adhesive as described in any one of claims 1 to 4, which requires no base coat and can be applied in one stroke.

7. The coated fabric according to claim 6, characterized in that, The base fabric A includes any one of Oxford cloth, polyester taffeta, cotton cloth, polyester cloth, spring spun or nylon taffeta; Preferably, the amount of adhesive applied in one pass is 10~50 g / m (dry weight). 2 ; Preferably, the drying temperature is 100~200℃ and the time is 0.5~5 min.

8. The high water pressure resistant coated fabric according to claim 6 or 7, characterized in that, The hydrostatic pressure of the high water pressure resistant coated fabric is ≥100000 Pa.

9. A water-based synthetic leather, characterized in that, The water-based synthetic leather is obtained by first applying a film or hot-pressing a film to the base fabric B, then coating the surface with the water-based adhesive as described in any one of claims 1 to 4, which requires no base coat and can be formed in one cut, and then performing a texturing or embossing process.

10. The water-based synthetic leather according to claim 9, characterized in that, The base fabric B includes any one of suede, spring spun, nylon spun or voile; Preferably, the amount of dry adhesive applied is 50~300 g / m². 2 .

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