JP2005060854A - Base fabric for waterproof layer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a base fabric for a waterproof layer for use in an air-permeable buffer method of construction which is a waterproof method of construction of concrete and having excellent chemical resistance to alkalis, acids, etc., and ozone resistance. <P>SOLUTION: The base fabric for the waterproof layer comprises ≥5 wt.% of acrylic fibers composed of ≥97 wt.% of acrylonitrile. The base fabric is preferably a dry-formed nonwoven fabric. The basic fabric surface on at least one side is more preferably made denser than the interior of the base fabric. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a base fabric used mainly for waterproof coating of concrete floors such as rooftops of buildings and verandas, and anticorrosion coating of concrete wall surfaces of sewage treatment plants and water purification plants.

In waterproofing and anticorrosion coating of concrete, a waterproof layer is formed on the concrete surface by a paint film. It is easy to produce. Therefore, a construction method (venting air cushioning method) in which a base fabric such as a non-woven fabric is first applied to the concrete surface and a coating film is applied thereon to form a waterproof layer is widely adopted. In this construction method, since the base fabric relieves distortion caused by cracks on the concrete surface, the waterproof layer is less likely to break.

Conventionally, polyester, nylon, or the like has been used as a base fabric (hereinafter referred to as a waterproof layer base fabric) that forms the waterproof layer (see, for example, Patent Document 1). However, in the case of waterproof coating on the rooftop or the like, there has been a problem that rainwater or the like that has entered from cracks in the coating film becomes alkaline water on the concrete surface and deteriorates the waterproof fabric. In addition, in sewage and water treatment plants, there is a problem that the anticorrosion performance is significantly lowered due to deterioration of the fibers constituting the waterproof layer base fabric due to sulfuric acid caused by generated hydrogen sulfide and ozone treatment for sterilization. It was.
Japanese Patent Application Laid-Open No. 07-034611

An object of the present invention is to provide a base fabric for waterproof layer that is excellent in chemical resistance and ozone resistance against alkalis, acids and the like in order to solve the above-mentioned problems.

As a result of diligent studies to achieve the above-mentioned object, the present inventors have reached the present invention by blending acrylic fiber comprising 97% by weight or more of acrylonitrile with a base fabric for waterproof layer. That is, the present invention is achieved by the following means.
(1) A waterproof fabric base fabric characterized by containing 5% by weight or more of acrylic fiber comprising 97% by weight or more of acrylonitrile.
(2) The base fabric for waterproofing layer according to (1), comprising a dry nonwoven fabric.
(3) The waterproof base fabric according to (1) or (2), wherein at least one surface of the base fabric is more dense than the inside of the base fabric.

  The base fabric for waterproof layer of the present invention is excellent in chemical resistance, and also has excellent ozone resistance due to the same action, and therefore can be suitably used as a base fabric for waterproof / anticorrosive coating of foundations such as mortar and concrete. The provision of such a waterproof layer base fabric is a notable point of the present invention, and has a great industrial significance.

  Hereinafter, the present invention will be described in detail. In the present invention, the term “waterproof” is used to include the meaning of “anticorrosion”.

The acrylic fiber employed in the present invention is not particularly limited as long as the acrylonitrile ratio as a whole is 97% by weight or more, and the acrylonitrile-based polymer constituting the fiber includes an acrylonitrile homopolymer, acrylonitrile, a known comonomer, and the like. A copolymer of these or a mixture thereof can be used. Here, the acrylonitrile ratio is the weight percent of acrylonitrile with respect to the total weight of the acrylonitrile-based polymer constituting the acrylic fiber.

  When the acrylonitrile ratio is less than 97% by weight, the chemical resistance and ozone resistance inherent to the fiber made of acrylonitrile are lowered, and the fiber properties are likely to deteriorate when exposed to alkaline water, sulfuric acid water, or ozone sterilization for a long time. . This chemical resistance and ozone resistance are particularly preferable because acrylic fibers having an acrylonitrile ratio of 100% by weight containing no copolymerization component exhibit outstanding performance.

  Here, the comonomer used for copolymerization is not particularly limited as long as it is copolymerizable with acrylonitrile, such as a vinyl compound. For example, alkyl acrylate, alkyl methacrylate, acrylic acid, methacrylic acid, methacrylonitrile, acrylamide, vinyl acetate. , Vinyl chloride, vinyl bromide, vinyl fluoride, vinylidene chloride, vinylidene bromide, styrene, styrene sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, styrene sulfonate, allyl sulfonate, methallyl sulfonate, Examples include ethylene and propylene.

  In order to produce acrylic fibers from such an acrylonitrile polymer, known spinning techniques such as wet spinning, dry wet spinning, and dry spinning can be applied.

  The base fabric for waterproof layer of the present invention is characterized by containing 5% by weight or more of the acrylic fiber employed in the present invention, and preferably 15% by weight or more. If it is less than 5% by weight, the base fabric is likely to deteriorate when it is exposed to an alkali or acid for a long period of time and cannot be employed.

As the fibers constituting the waterproof layer base fabric other than acrylic fibers employed in the present invention (hereinafter referred to as other types of fibers), one or more of natural fibers, regenerated fibers, semi-synthetic fibers, and synthetic fibers are used. Can be used as appropriate, but vinylon fiber, nylon fiber, polyester fiber, polypropylene fiber and polyethylene fiber are preferred from the viewpoint of chemical resistance and corrosion resistance, and nylon fiber and polyester are particularly preferred from the viewpoint of adhesion to a waterproof coating and economic efficiency. Fiber is preferred. In order to impart appropriate tensile strength and elastic modulus to the base fabric for waterproof layer, a fiber having self-adhesive property by heat or the like (hereinafter referred to as self-adhesive fiber) is used for some or all of other types of fibers. May be.

  Although there is no restriction | limiting in particular in the fineness of the acrylic fiber of this invention, and another kind fiber, If the fineness is 1-12 dtex, since the surface state of the coating film at the time of forming a coating film in the base fabric for waterproof layers will become favorable, preferable. Moreover, the fiber length can select a suitable thing according to the method and apparatus which produce the base fabric for waterproof layers.

The form of the base fabric for the waterproof layer of the present invention is not particularly limited, and examples thereof include knitted fabrics, woven fabrics, and nonwoven fabrics. It is desirable to employ a dry nonwoven fabric from the viewpoint of buffering properties and production costs. In addition, a laminate of the knitted fabric, woven fabric, non-woven fabric, or the like can also be used. In this case, if the acrylic fiber described above as the entire waterproof layer base fabric is contained in an amount of 5% by weight or more. The fiber configuration and form of each layer may be different. For example, a material that contains more acrylic fiber in the layer on the base side has a higher protective effect on the base surface.

It does not specifically limit as a creation method of the said knitted fabric, a woven fabric, a nonwoven fabric, etc., A general method is employable. For example, in the case of a dry nonwoven fabric, a thermal bond method in which an airlaid web or card web laminated with air is bonded by thermal fusion of self-adhesive fibers, a chemical bond method in which a binder emulsion is used, or a needle or water A method of joining by entanglement with a jet, and in the case of a wet nonwoven fabric, a method of dispersing fibers in water and forming a sheet by a wet papermaking method, and joining by a self-adhesive fiber or a binder emulsion as necessary Can do.

The base fabric for waterproof layer of the present invention has, as chemical resistance, for example, an alkali having a strength retention of 40% or more after being immersed in an aqueous 10% by weight sodium hydroxide solution at 60 ° C. for 65 hours, preferably It is desirable that it is 70% or more.

If the base fabric surface on the side where the waterproof coating is applied to form a coating film has a low fiber density, the waterproof coating is excessively absorbed and impregnated in the base fabric, and many waterproof coatings are used. Cost, and it takes time to dry the solvent etc. contained in the waterproof paint, leading to a delay in the construction period. In addition, the waterproof layer base fabric impregnated with an excessive waterproof paint also deteriorates air permeability and cushioning performance, and this causes a problem of swelling on the coating film surface. In addition, if the fiber density on the surface of the base fabric to which the waterproof coating is applied is low, that is, if there is little entanglement between the fibers, there is a problem that when the waterproof coating having high viscosity is spread, the fibers are peeled off and the painted surface becomes rough. . For this reason, it is preferable that at least one surface of the waterproof layer base fabric has a dense structure with a fiber density higher than that of the inside of the base fabric, and a waterproof paint is applied to the surface.

As a method for densifying the surface of at least one base fabric, the base fabric has a structure of two or more layers, a method in which a thermal calendar is applied to the layer containing a large amount of self-adhesive fibers, or a binder on the surface of the base fabric for waterproofing layer. The method of apply | coating or spraying a property emulsion and heat-drying is mentioned.

  The waterproof coating using the base fabric for waterproof layer of the present invention can be performed by a usual method. That is, the waterproof fabric base fabric of the present invention is attached to a base material such as cement mortar or concrete to be waterproofed with an appropriate adhesive, and a waterproof paint or resin is applied to the surface of the base fabric with a painting roller or a hammer. Apply and dry to form a waterproof coating. In addition, before affixing the waterproof layer base fabric to the base, it is common to perform base smoothing and primer treatment in order to improve waterproofness, corrosion resistance, and adhesion. Examples of waterproof paints include paints and resins such as urethane paints, rubber paints, polyester paints, and unsaturated polyester resins. Depending on the purpose, a paint such as a top coat may be applied repeatedly.

  Examples are shown below for facilitating the understanding of the present invention, but these are merely illustrative and the gist of the present invention is not limited thereby. In the examples, parts and percentages are shown on a weight basis unless otherwise specified. In addition, acrylic fiber is obtained by water-based suspension polymerization to obtain an acrylonitrile-based polymer having the composition shown in the table, and then the polymer is dissolved in a sodium thiocyanate aqueous solution to form a spinning stock solution. It was created by stretching and heat treatment.

[Examples 1-7, Comparative Examples 1-4]
In the fiber configuration and the base fabric creation method shown in Table 1, each fabric was made into a nonwoven fabric having a basis weight of 300 g / m ² , followed by thermal bond bonding by hot air drying treatment at 160 ° C. 7 was obtained. Similarly, the base fabric comparative examples 1-4 for waterproofing layers which deviate from this invention shown in Table 2 were obtained. Here, in Examples 4 and 6, and Comparative Example 4, a surface densification treatment was performed by passing a 200 ° C. hot roll through the paint construction surface (indicated as the upper layer in the table). The other fibers other than the acrylic fiber and the self-adhesive fiber of the present invention used here have a fineness of 5 dtex, a fiber length of 76 mm is used except in Example 7, and a fiber length of 6 mm is used in Example 7. did.

Tables 1 and 2 show the results of the chemical resistance test of these base fabrics and the paintability in actual painting, in terms of the surface state during painting and the state of the coating film after drying. Here, each performance was measured according to the following.
1. Chemical resistance: The base fabric was cut to a width of 15 mm and a length of 15 cm, immersed in a 10% NaOH aqueous solution, kept at 60 ° C., and after 65 hours, the tensile strength of the base fabric was measured to calculate the strength retention by the following formula. Tensile strength was measured with a Tensilon RTA-500 model manufactured by ORIENTEC at a test speed of 20 mm / min and a grip length of 10 cm. It can be considered that the higher the strength retention, the higher the chemical resistance.
Strength retention (%) = strength after test / strength before test x 100
2. Paintability in actual coating: Apply 0.15 kg / m ² of urethane resin primer (Sun Mitsui Chemicals Co., Ltd. Sun PC-F) to the mortar base, then urethane resin adhesive (Mitsui Chemicals Co., Ltd.) After applying 0.2kg / m ^{2 of} double bond), a base fabric cut to 0.9m x 1.8m is pasted, and a two-component urethane coating waterproofing agent (HC Eco manufactured by Hodogaya Construction Materials Co., Ltd.) The proof was stretched smoothly with a hammer to 2 kg / m ² , the surface condition during coating was visually observed, and evaluated according to the following evaluation criteria.
◎: Roughness is not observed on the surface, good ○: Roughness is observed on the surface, but is generally good ×: Roughness is recognized on the surface, and poor

  As shown in Table 1, in Examples 1-7, sufficient strength was maintained in the chemical resistance test. In particular, Examples 3, 5, 6, and 7 show that when the acrylic fiber of the present invention is 15% or more, further excellent chemical resistance is expressed. Among them, Examples 5 and 7 are particularly excellent in chemical resistance, and it can be seen that when the acrylonitrile ratio in the acrylic fiber is 100%, the chemical resistance works effectively.

On the other hand, as shown in Table 2, in Comparative Examples 1 and 2, the blending amount of the acrylic fiber employed in the present invention is small, and in Comparative Examples 3 and 4, the acrylonitrile ratio in the acrylic fiber is low. In either case, the excellent chemical resistance aimed by the present invention is not obtained.

  Regarding the paintability, Examples 4 and 6 in which one surface of the waterproof fabric is densified have excellent surface properties during painting. By densifying the painted surface of the waterproof layer base fabric, excessive suction of the paint is suppressed, the uneven surface of the nonwoven fabric does not appear on the surface, and the fibers are peeled off and fluffed even when spreading highly viscous paint. This is considered to be suppressed.

Claims (3)

  A waterproof fabric base fabric comprising 5% by weight or more of acrylic fiber composed of 97% by weight or more of acrylonitrile.   It consists of a dry-type nonwoven fabric, The base fabric for waterproof layers of Claim 1 characterized by the above-mentioned.   The base fabric for waterproof layer according to claim 1 or 2, wherein at least one surface of the base fabric is densified more than the inside of the base fabric.