JPS6058025B2 - asphalt waterproof sheet - Google Patents

Description

[Detailed Description of the Invention] The present invention is used for asphalt waterproofing work for building roofs, basements, underground passages, subways, etc., and has excellent mechanical strength, weather resistance, water resistance, corrosion resistance, and especially dimensional stability. This relates to an asphalt waterproof sheet using a special non-woven fabric as a core material.

In recent years, with the development of architecture and civil engineering, there is a demand for high performance in a wide variety of waterproofing fields.

Therefore, instead of asphalt loop ink, which uses conventional loop ink base paper as its core material, we have developed an asphalt waterproofing material (so-called stretch loop ink) whose core material is sheet-like nonwoven fabric, which is made by randomly accumulating and fixing synthetic fibers. J
The ISA600 standard is becoming widely used. There are two types of nonwoven fabrics: those made by dry method and those made by wet method.

Dry-laid nonwovens are classified because they form a web in a dry state, and wet-laid nonwovens form a web in a wet state in water using a conventional paper machine. There are several manufacturing methods for dry-processed non-woven fabrics, such as adhesive type, mechanical bonding type, and spinning type. Dry-processed non-woven fabrics are generally used as waterproof sheets, but the disadvantage of this is that the production speed is slow, and the production speed of each method is 20 m/min. This results in higher costs. In comparison, wet-processed nonwoven fabrics can be produced using paper machines at speeds of 100 to 300 m/min, resulting in high efficiency and low cost. Because it is bonded using soluble polyvinyl alcohol fibers (fibrous binder), it has poor water resistance and dimensional stability (it stretches due to the adhesive's rebound phenomenon), and it dries while being wrapped around the drying cylinder of the paper machine and tightened. , the material is paper-like, has high tensile strength but low tear strength, and has the disadvantage of poor asphalt impregnation properties. The present invention was achieved through research aimed at eliminating these drawbacks of wet-laid nonwoven fabrics and developing an asphalt waterproof sheet that is highly efficient, low-cost, has excellent water resistance, dimensional stability, and tear strength, is porous, and has a large amount of asphalt impregnation. The structure of the asphalt waterproofing sheet of the present invention is that the asphalt waterproofing sheet is made by impregnating and coating a nonwoven fabric with a waterproofing agent mainly made of asphalt and containing rubber and synthetic resin as necessary. It is a wet-laid nonwoven fabric made by dispersing fibers in water, uniformly mixing them, entangling them, and dehydrating them on a papermaking screen.The raw materials are strong corrosion-resistant fibers with a weight of 40-8%,
It is composed of 10-5% by weight of low-softening point polyester fibers and 3-15% by weight of polyvinyl alcohol fibers, and is subjected to asphalt impregnation and coating processes at the intertwining joint of the strong corrosion-resistant fibers and the low-softening point polyester fibers. This asphalt waterproof sheet is characterized by low softening point polyester fibers being melted, bound, and solidified by the heat of the molten asphalt.

The wet-laid nonwoven fabric that is the core material of the asphalt tarpaulin sheet is manufactured using a regular Fourdrinier paper machine or a circular wire paper machine. The most suitable fibers are ordinary polyester fibers, glass fibers, or a mixture of the two.

The advantages of these are that it is possible to produce a sheet base material that is rigid, strong, repulsive, has strong tensile strength, is water resistant and porous, has good asphalt impregnation, and has good dimensional stability. The use of low softening point polyester fibers is a feature of the present invention, and those having a softening point of 100 to 150°C are used.

During the papermaking process, the sheet does not function as a binder (adhesive action) at all, even when dispersed in water or due to the pressure and heat of the drying cylinder, and the sheet remains porous and bulky and becomes paper-like. Since the asphalt does not become dense, it has the advantage of being able to be impregnated and coated with high-quality asphalt that has good impregnation properties and high melt viscosity, or waterproofing agent containing a large amount of rubber or synthetic resin. This low softening point polyester fiber can be used in the next asphalt impregnation and coating process to approximately 200%
The asphalt melted at about ℃ gradually softens and becomes sticky, sufficiently binding and solidifying the intertwined fibers. Since this nonwoven fabric is bound by the fusion strength of these low softening point polyester fibers, it has better water resistance and adhesive properties compared to nonwoven fabrics that are bonded only with emulsion type adhesives or polyvinyl alcohol fibers, such as conventional wet-laid nonwoven fabrics. There is no dimensional stability defect caused by the recoil phenomenon.
Next, polyvinyl alcohol fibers are also used in conventional wet-laid nonwoven fabrics, but as mentioned above, they have poor water resistance, so in the present invention, they are added in as small a quantity as possible to maintain a sheet-like shape during the papermaking process. NitoS゛meru.

If the tough corrosion-resistant fiber is less than 40% by weight, it will be inferior in toughness and dimensional stability, and if it is more than 8% by weight, the adhesion between the fibers will be poor, and it will be difficult to form a smooth structure.

If the low softening point polyester fiber is less than 1% by weight, adhesion and fixation will be insufficient, and if it is more than 5% by weight, the nonwoven fabric will become weak.

If the polyvinyl alcohol fiber is less than 3% by weight, it is inconvenient to hold it in a sheet form during the papermaking process, and if it is more than 15% by weight, it becomes papery in the drying cylinder and becomes too dense, resulting in poor asphalt impregnation properties.

The asphalt waterproof sheet having the above structure does not use the conventional dry nonwoven fabric, which has a slow production speed, but uses a wet nonwoven fabric that can be produced at high speed and at low cost using a conventional paper machine.
The raw materials are mainly strong, corrosion-resistant fibers such as polyester fibers and glass fibers, and the fibers are bonded and fixed at a temperature of about 200'C using molten asphalt heat via low softening point polyester fibers to create a nonwoven fabric. Asphalt waterproofing sheet is impregnated with asphalt and coated with asphalt.It is a wet-laid non-woven fabric made by dispersing various raw material fibers of a specific composition in water, uniformly mixing and entangling them, and dewatering them on a papermaking screen. Because of this, it is porous and has a large amount of asphalt impregnated.
It has excellent water resistance, weather resistance, and corrosion resistance, and in the next asphalt processing process, the intertwined joints of strong corrosion-resistant fibers and low softening point polyester fibers are bonded and hardened, and the material is uniform. Therefore, it has good tear strength and dimensional stability. This is useful as an asphalt waterproof sheet that is durable, has excellent crack resistance and tear resistance, and is inexpensive.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the structure of the nonwoven fabric used in the present invention. Figure 2 is a cross-sectional view of an asphalt waterproof sheet. 1...
... Tough corrosion-resistant fiber, 2 ... Low softening point polyester fiber, 3 ... Polyvinyl alcohol fiber, 4 ... Asphalt-based waterproofing agent, 5
... Fiber entanglement binding part, A ... Nonwoven fabric used in the present invention, B ... Asphalt waterproof sheet, A'' ... Nonwoven fabric impregnated with waterproofing agent.

Claims (1)

[Claims] 1. Impregnating a nonwoven fabric with a waterproofing agent mainly composed of asphalt,
In the coated asphalt waterproof sheet, the nonwoven fabric is a wet nonwoven fabric that is formed by dispersing raw material fibers in water using a papermaking method, uniformly mixing and entangling them, and dewatering them on a papermaking screen. Consisting of 40-80% by weight of tough corrosion-resistant fibers, 10-50% by weight of low-softening point polyester fibers, and 3-15% by weight of polyvinyl alcohol fibers, and the intertwining joint of the tough corrosion-resistant fibers and the low-softening point polyester fibers. An asphalt waterproof sheet characterized in that low softening point polyester fibers are melted and bound and solidified by the heat of molten asphalt. 2. The asphalt waterproof sheet according to claim 1, wherein the strong corrosion-resistant fibers are polyester fibers, glass fibers, or a combination thereof.