US20130129999A1

US20130129999A1 - Surface-waterproofing sheet for mineral board using a mixed-use nonwoven fabric and a waterproofing coating layer, and a production method therefor

Info

Publication number: US20130129999A1
Application number: US13/814,373
Authority: US
Inventors: Gil-Ho KANG; Seong-Moon Jung; Sun-Joo Kim; Joo-Hwan Seo
Original assignee: LG Hausys Ltd
Current assignee: LX Hausys Ltd
Priority date: 2010-09-14
Filing date: 2011-09-14
Publication date: 2013-05-23
Also published as: JP5668140B2; CN103052747B; WO2012036466A3; KR101199686B1; WO2012036466A2; JP2013540917A; KR20120028173A; CN103052747A

Abstract

The present invention relates to a surface-waterproof sheet for inorganic boards including multi-use non-woven fabrics and a waterproof coating layer, and a method of manufacturing the same. The method includes preparing a multi-use non-woven fabric composed of cellulose fibers, glass fibers and organic fibers; preparing a waterproof coating solution containing a powdery acrylic binder, water, an inorganic filler, a water repellent, a pigment and an antimicrobial agent; and coating the waterproof coating solution on the multi-use non-woven fabric, followed by drying the waterproof coating solution, thereby providing surface-waterproof sheet for inorganic boards for buildings, which has improved adhesion to the inorganic board and economic feasibility.

Description

TECHNICAL FIELD

The present invention relates to a surface-waterproof sheet for inorganic boards including a multi-use non-woven fabric and a waterproof coating layer and a method of manufacturing the same, and more particularly, to a technology of providing a surface-waterproof sheet, which include a single nonwoven fabric layer and a waterproof coating layer formed thereon to improve adhesion to an inorganic board while ensuring economic feasibility.

BACKGROUND ART

As a waterproof surface material for gypsum boards for buildings, a 2-layer structure surface material has been generally used in the art. Here, the 2-layer structure refers to a structure including an outer layer made of cellulose fibers and an inner core adhesive layer placed beneath the outer layer. At this time, to provide waterproofing properties to the 2-layer structure surface material, the entirety of the 2-layer structure surface material is generally impregnated into a waterproof binder composition. However, as the inner core adhesive layer is impregnated into the waterproof binder composition, adhesion to the gypsum board is lowered and dimensional stability and cutting performance are also lowered, thereby deteriorating the overall properties of the surface material.

DISCLOSURE

Technical Problem

An aspect of the present invention is to provide a surface-waterproof sheet for inorganic boards, in which a waterproof paper body to be adhered to an inorganic board is formed of a single layer of multi-use non-woven fabrics composed of cellulose fibers, glass fibers and organic fibers, and is then coated with a waterproof coating solution including binder powder, water, an inorganic filler, a water repellent, a pigment and an antimicrobial agent, thereby improving waterproof properties and adhesion to the inorganic board.
Another aspect of the present invention is to provide a method of manufacturing a surface-waterproof sheet for inorganic boards, which can improve dimensional stability and cutting properties while securing strength of the inorganic board by adjusting a pore size and a basis weight of multi-use non-woven fabrics, and the coating amount, viscosity and composition of a waterproof coating solution.

Technical Solution

In accordance with one aspect of the present invention, a surface-waterproof sheet for inorganic boards includes: a multi-use non-woven fabric composed of cellulose fibers, glass fibers and organic fibers; and a waterproof coating layer coated on the multi-use non-woven fabric.
The multi-use non-woven fabric may include 30˜70 wt % of the cellulose fibers, 28˜60 wt % of the glass fibers and 2˜20 wt % of the organic fibers.
The cellulose fibers may have an average diameter of 5 μm to 100 μm and an average length of 1 mm to 30 mm; and each of the glass fibers and the organic fibers may have an average diameter of 5 μm to 20 μm and an average length of 1 mm to 30 mm
The multi-use non-woven fabric may be formed as a single layer of the nonwoven fabric having a basis weight of 30 g/m²to 100 g/m², and may have a thickness of 0.25 mm to 0.55 mm
The multi-use non-woven fabric may further include 0.1˜3 wt % of a dry paper strengthener or wet paper strengthener. The dry paper strengthener may contain starch or polyacrylamide, and the wet paper strengthener may contain at least one selected from among urea formaldehyde resins, melamine formaldehyde resins, polyamide resins, glyoxylated polyacrylamide resins, and polyethylene imine resins.
The waterproof coating layer may be formed using a waterproof coating solution that includes 3˜30 wt % of a powdery acrylic binder, 10˜50 wt % of water, 20˜70 wt % of an inorganic filler, 0.5˜10 wt % of a water repellent, 0.5˜5 wt % of a pigment, and 0.2˜5 wt % of an antimicrobial agent.
The waterproof coating solution may have a viscosity of 50˜500 cps. Here, the inorganic filler may include calcium carbonate (CaCO₃) having an average particle size of 5 μm to 50 μm, and the water repellent may include a fluorocarbon or wax type water repellent.
The waterproof coating layer may be permeated up to 5% to 80% of a thickness of the non-woven fabric from an upper surface of the non-woven fabric to a bottom thereof. Here, the non-woven fabric may have an average pore size of 10 μm to 100 μm in a region into which the waterproof coating layer is not permeated, and an average pore size of 5 μm to 50 μm in a region into which the waterproof coating layer is permeated.
The surface-waterproof sheet may have a total thickness of 0.27 mm to 0.57 mm The inorganic board may include at least one selected from among medium density fiberboard (MDF), plywood, cellulose fibers-reinforced cement board, magnesium board, glued laminated timber, high-density fiberboard, ceramic tile, porcelain tile, ceramic board, gypsum board, cement board, and MgO board.
In accordance with another aspect of the present invention, a method of manufacturing a surface-waterproof sheet for inorganic boards includes: (a) preparing a multi-use non-woven fabric by mixing cellulose fibers, glass fibers and organic fibers; (b) preparing a waterproof coating solution containing a powdery acrylic binder, water, an inorganic filler, a water repellent, a pigment, and an antimicrobial agent; and (c) coating the waterproof coating solution on the multi-use non-woven fabric, followed by drying the waterproof coating solution.
The coating of the waterproof coating solution may be performed by one method selected from among drum coating, roll coating, knife coating, spray coating, and comma coating; and the drying of the waterproof coating solution may be performed at a temperature of 100° C. to 200° C. for 1 to 10 minutes.

Advantageous Effects

In the surface-waterproof sheet for inorganic boards according to the present invention, a waterproof paper body to be adhered to an inorganic board is formed as a single layer of multi-use non-woven fabrics, and a waterproof coating solution is permeated up to 5% to 80% of a thickness of the non-woven fabric layer from an upper surface of the non-woven fabric layer to a bottom thereof, thereby providing better waterproof properties than existing surface materials while improving adhesion to the inorganic board.
Further, the method of manufacturing a surface-waterproof sheet for inorganic boards according to the present invention may improve dimensional stability and cutting properties while securing strength of the inorganic board by adjusting a pore size and a basis weight of the multi-use non-woven fabrics, and the coating amount, viscosity and composition of the waterproof coating solution.

DESCRIPTION OF DRAWING

FIG. 1 is a cross-section view of a surface-waterproof sheet for inorganic boards according to one embodiment of the present invention.

FIG. 2 is a flowchart of a method of manufacturing a surface-waterproof sheet for inorganic boards according to one embodiment of the present invention.

FIG. 3 is a diagram illustrating the method of manufacturing a surface-waterproof sheet for inorganic boards according to the embodiment of the present invention.

BEST MODE

Next, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The above and other aspects, features, and advantages of the present invention will become apparent from the detailed description of the following embodiments in conjunction with the accompanying drawings. It should be understood that the present invention is not limited to the following embodiments and may be embodied in different ways, and that the embodiments are given to provide complete disclosure and a thorough understanding of the present invention to those skilled in the art. The scope of the present invention is defined only by the claims. The same components will be denoted by the same reference numerals throughout the specification.
FIG. 1 is a cross-sectional view of a surface-waterproof sheet for inorganic boards according to one embodiment of the present invention.
First, referring to FIG. 1, a multi-use non-woven fabric 100 composed of cellulose fibers, glass fibers and organic fibers is shown.
The multi-use non-woven fabric may include 30˜70 wt % of the cellulose fibers, 28˜60 wt % of the glass fibers and 2˜20 wt % of the organic fibers. Also, the cellulose fibers may have an average diameter of 5 μm to 100 μm, and an average length of 1 mm to 30 mm
Here, the cellulose fibers serve to adjust an average pore size of the nonwoven fabric. If the cellulose fibers are present in an amount of less than 30 wt % or most cellulose fibers have an average size below the aforementioned range, the pore size of the nonwoven fabric becomes too large, causing deterioration of waterproof properties.
If the cellulose fibers are present in an amount of more than 70 wt % or have an average size above the aforementioned range, the amount of glass fibers or organic fibers becomes excessively increased, causing reduction in tensile strength of the multi-use non-woven fabric.
Also, each of the glass fibers and the organic fibers may have an average diameter of 5 μm to 20 μm and an average length of 1 mm to 30 mm The glass fibers are present in an amount of 28 wt % to 60 wt % and the organic fibers are present in an amount of 2 wt % to 20 wt %.
Here, the glass fibers serve to secure strength and waterproof properties of the multi-use non-woven fabric and thus secure dimensional stability. If the glass fibers are present in an amount of less than 28 wt % or have an average size below the aforementioned range, the non-woven fabric has low strength. If the glass fibers are present in an amount of more than 60 wt %, the pore size of the non-woven fabric is excessively increased, thereby causing deterioration in waterproof properties.
Further, the organic fibers serve to keep certain waterproof properties and folding strength while providing flexibility to the non-woven fabric. If the organic fibers are present in an amount of less than 2 wt % or have an average size below the aforementioned range, the flexibility of the multi-use non-woven fabric can be deteriorated. If the organic fibers are present in an amount of more than 20 wt %, the pore size of the non-woven fabric is excessively increased, thereby causing deterioration in waterproof properties and strength of the non-woven fabric. Next, the multi-use non-woven fabric 100 further includes 0.1˜3 wt % of a dry paper strengthener or wet paper strengthener. The dry paper strengthener includes starch or polyacrylamide, and the wet paper strengthener includes at least one selected from among urea formaldehyde resins, melamine formaldehyde resins, polyamide resins, glyoxylated polyacrylamide resins, and polyethylene imine resins. The dry paper strengthener or the wet paper strengthener may be optionally added in accordance with the use of inorganic boards.
The raw materials for the multi-use non-woven fabric are formed to a thickness of 0.25 mm to 0.55 mm Further, the multi-use non-woven fabric may be formed as a single non-woven fabric layer having a basis weight of 30 g/m²to 100 g/m². Herein, the term “thickness of the multi-use non-woven fabric” substantially refers to the sum of the thickness of the non-woven fabric 100 and the thickness of a waterproof coating solution permeation layer 110, as shown in FIG. 1. If the thickness of the multi-use non-woven fabric is less than 0.25 mm, the waterproof sheet cannot function as desired. If the thickness of the multi-use non-woven fabric is more than 0.55 mm, air-permeability required of the waterproof sheet can be deteriorated.
In addition, performance of the waterproof sheet can be deteriorated if the basis weight of the non-woven fabric is less than 30 g/m², and the air-permeability can be deteriorated if the basis weight of the non-woven fabric exceeds 100 g/m².
The waterproof sheet according to the present invention includes a waterproof coating layer 120 on the multi-use non-woven fabric.
Here, the waterproof coating layer 120 is formed of a waterproof coating solution which contains 3˜30 wt % of a powdery acrylic binder, 10˜50 wt % of water, 20˜70 wt % of an inorganic filler, 0.5˜10 wt % of a water repellent, 0.5˜5 wt % of a pigment, and 0.2˜5 wt % of an antimicrobial agent.
The inorganic filler may be calcium carbonate (CaCO₃) having an average particle size of 5 μm to 50 μm, and the water repellent may be a fluorocarbon or wax type water repellent.
Here, the waterproof coating solution may have a viscosity of 50˜500 cps. If the viscosity of the waterproof coating solution is lower than 50 cps, the amount of the coating solution permeated into the multi-use non-woven fabric decreases, causing the waterproof coating layer 120 to be easily separated. If the viscosity is higher than 500 cps, the amount of the coating solution permeated into the multi-use non-woven fabric excessively increases, causing deterioration in adhesion to the inorganic board.
Accordingly, the waterproof coating solution may have a viscosity ranging from 30 g/m²to 200 g/m². At this time, the waterproof coating layer 120 may have a coating structure that is permeated up to 5% to 80% of the thickness of the non-woven fabric from an upper surface of the non-woven fabric to a bottom thereof.
Further, like the effect of the viscosity, if the coating amount and the permeation thickness of the waterproof coating solution are less than the respective lower limits, the coating layer can be easily peeled off. If the coating amount and the permeation thickness of the waterproof coating solution exceed the upper limits, adhesion of the waterproof sheet can be deteriorated.
In the present embodiment, the surface-waterproof sheet for inorganic boards is formed by coating one layer of the multi-use non-woven fabric 100+110 with the waterproof coating layer 110+120. At this time, the non-woven fabric has an average pore size of 10 μm to 100 μm in a region 100 into which the waterproof coating layer 120 is not permeated, and an average pore size of 5 μm to 50 μm in a region 110 into which the waterproof coating layer 120 is permeated. Here, a pore size of the non-woven fabric smaller than the lower limit can cause difficulty in manufacture of the waterproof sheet and deterioration of air-permeability of the waterproof sheet, and a pore size of the non-woven fabric higher than the upper limit can cause deterioration of waterproof properties.
Also, the surface-waterproof sheet including the waterproof coating layer may have a total thickness of 0.27 mm to 0.57 mm Here, if the total thickness of the surface-waterproof sheet is less than 0.27 mm, waterproofing properties can be deteriorated, and if the total thickness of the surface-waterproof sheet is greater than 0.57 mm, air permeability can be deteriorated. In such cases, the properties of the surface-waterproof sheet to be adhered to an inorganic board can be deteriorated.
At this time, the inorganic board may include at least one selected from among medium density fiberboard (MDF), plywood, cellulose fiber-reinforced cement board, magnesium board, glued laminated timber, high density fiberboard, ceramic tile, porcelain tile, ceramic board, gypsum board, cement board, and MgO board.
The waterproofing properties and air permeability will be described below in more detail with reference to examples.
Next, a method of manufacturing a surface-waterproof sheet according to the present invention will be described.
FIG. 2 is a flowchart of a method of manufacturing a surface-waterproof sheet for inorganic boards according to one embodiment of the present invention.
Referring to FIG. 2, the method includes preparing a multi-use non-woven fabric by mixing cellulose fibers, glass fibers and organic fibers (S100); preparing a waterproof coating solution containing a powdery acrylic binder, water, an inorganic filler, a water repellent, a pigment, and an antimicrobial agent (S110); and coating the waterproof coating solution on the multi-use non-woven fabric, followed by drying the waterproof coating solution (S120).
Here, although operation of preparing a multi-use non-woven fabric (S100) and operation of preparing a waterproof coating solution (S110) are shown in sequence, these operations can be performed independently, and thus the present invention is not limited thereto.
Further, the compositions or contents of the multi-use non-woven fabric and the waterproof coating solution are the same as those described above with reference to FIG. 1.
Next, operation of coating the waterproof coating solution is performed by one process selected from among drum coating, roll coating, knife coating, spray coating, and comma coating. Further, drying is performed at a temperature of 100° C. to 200° C. for 1 to 10 minutes. Here, if the drying temperature is lower than 100° C. or the drying time is shorter than 1 minute, the waterproof coating layer is not normally formed. On the other hand, if the drying temperature is higher than 200° C. or the drying time is longer than 10 minutes, the waterproof coating layer can be damaged, thereby deteriorating the waterproofing properties.
FIG. 3 is a schematic diagram of the method of manufacturing the surface-waterproof sheet for inorganic boards according to the embodiment of the present invention, which shows a drum coating process.
Referring to FIG. 3, a coating drum 220 is used for successively uncoiling a multi-use non-woven fabric 210 on a multi-use non-woven fabric roll 200. Here, the coating drum 220 is configured to completely block one side of the non-woven fabric 210 such that a waterproof coating solution 230 can be applied only to the one side of the non-woven fabric 210 in a coating container 240 filled with the waterproof coating solution 230.
Through this procedure, the waterproof coating solution 230 is permeated up to 5% to 80% of the thickness of the non-woven fabric 210 from an upper surface of the non-woven fabric 210 to a bottom thereof, and a region of the non-woven fabric 210 under this range is maintained without being permeated by the waterproof coating solution, thereby maintaining adhesion to the inorganic board.
Next, a knife 245 is placed above the non-woven fabric 210 and is used to adjust the thickness of the waterproof coating layer by removing the waterproof coating solution 230, which comes out of the coating drum 220 in a coated state on the non-woven fabric 210.
Then, the surface-waterproof sheet is dried through a drier 250 and wound in the form of a surface-waterproof paper roll 260.
As described above, the surface-waterproof sheet according to the present invention has excellent air permeability and waterproofing properties. In addition, the surface-waterproof sheet according to the present invention secures excellent dimensional stability and cutting properties while securing tensile strength. The present invention will be described in more detail with reference to the following examples and Table 1.
First, the surface-waterproof sheets of the following examples were prepared by drum coating, and detailed compositions and drying conditions were as follows.

EXAMPLE 1

On a 0.32 mm thick multi-use non-woven fabric composed of 55 wt % of cellulose fibers, 40 wt % of glass fibers and 5 wt % of PET fibers and having a basis weight of 70 g/m², a waterproof coating solution containing 50 g of a thermosetting acrylic binder (solid content: 45%), 50 g of water, 125 g of calcium carbonate (CaCO₃), 3 g of a water repellent, 0.3 g of a pigment, and 2 g of an anti-microbial/mold agent was coated in an amount of 60 g/m², followed by drying at 130° C. for 3 minutes.

EXAMPLE 2

The surface-waterproof sheet was prepared in the same manner as in Example 1 except that a 0.44 mm thick multi-use non-woven fabric composed of 55 wt % of cellulose fibers, 35 wt % of glass fibers and 10 wt % of PET fibers and having a basis weight of 80 g/m²was used.

EXAMPLE 3

The surface-waterproof sheet was prepared in the same manner as in Example 1 except that the waterproof coating solution was coated in an amount of 100 g/m²on the same non-woven fabric as in Example 1.

EXAMPLE 4

Throughout a 0.25 mm thick multi-use non-woven fabric composed of 60 wt % of cellulose fibers, 25 wt % of glass fibers and 15 wt % of PET fibers and having a basis weight of 30 g/m², a waterproof coating solution containing 45 g of a thermosetting acrylic binder (solid content: 45%), 50 g of water, 125 g of calcium carbonate (CaCO₃) and 3 g of a water repellent was impregnated in an amount of 30 g/m², followed by drying at 130° C. for 3 minutes.

Example 5

The surface-waterproof sheet was prepared in the same manner as in Example 4 except that the waterproof coating solution was coated in an amount of 200 g/m²on the surface of the non-woven fabric.

EXAMPLE 6

The surface-waterproof sheet was prepared in the same manner as in Example 1 except that the water repellent was not added to the coating solution and was coated on the surface of the non-woven fabric by spray coating before drying.

COMPARATIVE EXAMPLE 1

The surface-waterproof sheet was prepared in the same manner as in Example 2 except that the waterproof coating solution was impregnated into the non-woven fabric instead of being partially permeated into the non-woven fabric.

COMPARATIVE EXAMPLE 2

The surface-waterproof sheet was prepared using the same non-woven fabric as in Example 1 and a waterproof coating solution containing 100 g of a thermosetting acrylic binder (solid content: 45%), 50 g of water, 30 g of calcium carbonate and 10 g of a water repellent was impregnated throughout the non-woven fabric.

COMPARATIVE EXAMPLE 3

On a 0 3 mm thick multi-use non-woven fabric composed of 30 wt % of cellulose fibers and 70 wt % of glass fibers and having a basis weight of 50 g/m², a waterproof coating solution containing 30 g of a thermosetting acrylic binder (solid content: 45%), 45 g of water, 200 g of calcium carbonate and 6 g of a water repellent was coated in an amount of 210 g/m²by bar coating, followed by drying at 130° C. for 3 minutes.

COMPARATIVE EXAMPLE 4

The surface-waterproof sheet was prepared in the same manner as in Comparative Example 3 except that the waterproof coating solution was coated in an amount of 20 g/m².

COMPARATIVE EXAMPLE 5

On a 0.32 mm thick multi-use non-woven fabric composed of 55 wt % of cellulose fibers, 40 wt % of glass fibers and 5 wt % of PET fibers and having a basis weight of 120 g/m², a waterproof coating solution containing 50 g of a thermosetting acrylic binder (solid content: 45%), 50 g of water, 125 g of calcium carbonate (CaCO₃), 3 g of a water repellent, 0.3 g of a pigment and 2 g of an anti-microbial/mold agent was coated in an amount of 60 g/m², followed by drying at 130° C. for 3 minutes.

COMPARATIVE EXAMPLE 6

The surface-waterproof sheet was prepared in the same manner as in Example 1 except that the non-woven fabric had a thickness of 0.6 mm

COMPARATIVE EXAMPLE 7

The surface-waterproof sheet was prepared in the same manner as in Example 1 except that the multi-use non-woven fabric was composed of 75 wt % of cellulose fibers, 24 wt % of glass fibers, and 1 wt % of PET fibers.

COMPARTIVE EXAMPLE 8

The surface-waterproof sheet was prepared in the same manner as in Example 1 except that, in the multi-use non-woven fabric, the cellulose fibers had an average diameter of 120 μm and an average length of 50 mm, and the glass fibers and PET fibers had an average diameter of 50 μm and an average length of 50 mm
In the above examples and the comparative examples, the basis weight and the thickness were measured according to KSK ISO 9073-1,2, and the pore size of the waterproof sheet was measured using a capillary flow porometer (Model: CFP-1200 AEIL). Moisture permeability (Cob test) was measured according to KS MISO 535.
Air permeability was measured under a pressure of 196 Pa according to KSK ISO 9073-15. Tensile strength was measured according to KSK ISO 9073-18.
Core adhesion was evaluated based on fracture ratio at an interface between a waterproof sheet and a gypsum board when separating a surface-waterproof sheet after preparing the gypsum board using the surface-waterproof sheet. An area ratio separated from the interface in the range of 0˜20% was evaluated as high, an area ratio in the range of 20˜60% was evaluated as middle, and an area ratio of 60% or more evaluated as low.
Surface quality was evaluated as high, milled and low according to surface roughness and whether the glass fibers were exposed. Foldability was evaluated depending on whether the waterproof sheet was efficiently folded and cracking occurred at a folded portion when the waterproof sheet was folded.

TABLE 1

	Basis	Moisture

	weight of			permeability
	non-woven		Coating	(g)		Tensile

fabric

Thickness

solution

Cob 60

Cob 180

Air

strength

Core

Surface

Economic

(g/m²)

(mm)

(g/m²)

On Top

permeability

Dry

Wet

adhesion

quality

Foldability

feasibility

Example	70	0.32	60	8.2	20	100	7.8	3.7	High	High	High	High
1
Example	80	0.44	60	7.8	15	150	5.9	2.9	High	High	High	High
2
Example	70	0.32	100	7.9	26	20	7.8	3.6	High	High	High	High
3
Example	30	0.25	30	7	16	100	8.3	4.0	High	High	High	High
4
Example	30	0.25	200	8.5	16	130	6.8	3.9	High	High	High	High
5
Example	70	0.32	60	7.5	120	180	7.8	3.7	High	High	High	High
6
Comparative	80	0.44		8.3	13	150	10.5	4.6	Low	Middle	Low	High
Example 1
Comparative	70	0.32		12	18	150	12.7	3.2	Low	Middle	High	High
Example 2
Comparative	50	0.30	210	—	—	0	—	—	High	Low	Low	High
Example 3
Comparative	50	0.30	20	—	—	0	—	—	Middle	Low	Middle	Low
Example 4
Comparative	120	0.32	60	9.3	14	140	11.3	3.4	Low	Middle	Low	Low
Example 5
Comparative	70	0.6	60	8.7	17	160	10.8	4.1	Low	Low	Low	Low
Example 6
Comparative	70	0.32	60	8.5	18	180	12.5	4.2	Low	High	Middle	Low
Examplee 7
Comparative	70	0.32	60	8.5	18	180	8.6	3.8	Middle	Low	Low	Low
Example 8

As described above, in the surface-waterproof sheet for inorganic boards according to the present invention, the waterproof paper body to be adhered to an inorganic board is formed as a single layer of multi-use non-woven fabrics, and a waterproof coating solution is permeated up to 5% to 80% of the non-woven fabric layer from an upper surface of the non-woven fabric layer to a bottom thereof, thereby providing better waterproof properties than existing surface materials while improving properties in terms of adhesion to an inorganic board, surface quality, foldability, and economic efficiency.
Further, in the method according to the present invention, the pore size and the basis weight of the multi-use non-woven fabrics, and the coating amount, viscosity and composition of the waterproof coating solution are adjusted, thereby improving dimensional stability and cutting properties while securing strength of the inorganic board.
Although some embodiments have been described, it will be understood by those skilled in the art that these embodiments are provided for illustration only, and various modifications, changes, alterations and equivalent embodiments can be made without departing from the scope of the present invention. Therefore, the scope and spirit of the present invention should be defined only by the accompanying claims and equivalents thereof.

Claims

1. A surface-waterproof sheet for inorganic boards, comprising a multi-use non-woven fabric comprising cellulose fibers, glass fibers and organic fibers; and

a waterproof coating layer coated on the multi-use non-woven fabric.

2. The surface-waterproof sheet according to claim 1, wherein the non-woven fabric comprises 30˜70 wt % of the cellulose fibers, 28˜60 wt % of the glass fibers, and 2˜20 wt % of the organic fibers.

3. The surface-waterproof sheet according to claim 1, wherein the cellulose fibers have an average diameter of 5 μm to 100 μm and an average length of 1 mm to 30 mm

4. The surface-waterproof sheet according to claim 1, wherein each of the glass fibers and the organic fibers has an average diameter of 5 μm to 20 μm and an average length of 1 mm to 30 mm

5. The surface-waterproof sheet according to claim 1, wherein the multi-use non-woven fabric is formed as a single layer of the nonwoven fabric having a basis weight of 30 g/m²to 100 g/m².

6. The surface-waterproof sheet according to claim 1, wherein the multi-use non-woven fabric has a thickness of 0.25 mm to 0.55 mm

7. The surface-waterproof sheet according to claim 1, wherein the multi-use non-woven fabric further comprises 0.1˜3 wt % of a dry paper strengthener or wet paper strengthener.

8. The surface-waterproof sheet according to claim 7, wherein the dry paper strengthener contains starch or polyacrylamide, and the wet paper strengthener contains at least one selected from among urea formaldehyde resins, melamine formaldehyde resins, polyamide resins, glyoxylated polyacrylamide resins, and polyethylene imine resins.

9. The surface-waterproof sheet according to claim 1, wherein the waterproof coating layer is formed using a waterproof coating solution that comprises 3˜30 wt % of a powdery acrylic binder, 10˜50 wt % of water, 20˜70 wt % of an inorganic filler, 0.5˜10 wt % of a water repellent, 0.5˜5 wt % of a pigment, and 0.2˜5 wt % of an antimicrobial agent.

10. The surface-waterproof sheet according to claim 9, wherein the waterproof coating solution has a viscosity of 50˜500 cps.

11. The surface-waterproof sheet according to claim 9, wherein the waterproof coating solution is coated in an amount of 30˜200 g/m²on the multi-use non-woven fabric.

12. The surface-waterproof sheet according to claim 9, wherein the inorganic filler comprises calcium carbonate (CaCO₃) having an average particle size of 5 μm to 50 μm.

13. The surface-waterproof sheet according to claim 9, wherein the water repellent comprises a fluorocarbon or wax type water repellent.

14. The surface-waterproof sheet according to claim 1, wherein the waterproof coating layer is permeated up to 5% to 80% of a thickness of the non-woven fabric from an upper surface of the non-woven fabric to a bottom thereof.

15. The surface-waterproof sheet according to claim 14, wherein the non-woven fabric has an average pore size of 10 μm to 100 μm in a region into which the waterproof coating layer is not permeated, and an average pore size of 5 μm to 50 μm in a region into which the waterproof coating layer is permeated.

16. The surface-waterproof sheet according to claim 1, wherein the surface-waterproof sheet has a total thickness of 0.27 mm to 0.57 mm

17. The surface-waterproof sheet according to claim 1, wherein the inorganic board comprises at least one selected from among medium density fiberboard (MDF), plywood, cellulose fibers-reinforced cement board, magnesium board, glued laminated timber, high-density fiberboard, ceramic tile, porcelain tile, ceramic board, gypsum board, cement board, and MgO board.

18. A method of manufacturing a surface-waterproof sheet for inorganic boards, the method comprising the steps of:

(a) preparing a multi-use non-woven fabric by mixing cellulose fibers, glass fibers and organic fibers;

(b) preparing a waterproof coating solution containing a powdery acrylic binder, water, an inorganic filler, a water repellent, a pigment, and an antimicrobial agent; and

(c) coating the waterproof coating solution on the multi-use non-woven fabric, followed by drying the waterproof coating solution.

19. The method according to claim 18, wherein the waterproof coating solution is coated by one method selected from among drum coating, roll coating, knife coating, spray coating, and comma coating.

20. The method according to claim 18, wherein the waterproof coating solution is dried at a temperature of 100° C. to 200° C. for 1 to 10 minutes.