JPH09323384A - Waterproof sheet - Google Patents

Abstract

(57) Abstract: [PROBLEMS] To provide a waterproof sheet which has high strength, high tear strength, high elastic modulus in spite of being soft and light, and which is also simple in process. SOLUTION: A woven fabric composed of polymer filaments substantially composed of repeating units represented by the following general formula (1), and the relationship between the weaving density and the total fineness of each of the warp and the weft satisfies the following formula (2). A waterproof sheet having at least one surface coated with a thermoplastic resin or rubber. Embedded image 900 ≧ weave density (books / inch) × √ total fineness ≧ 400 (2)

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waterproof sheet. More specifically, it relates to a waterproof sheet having a high strength and a high elastic modulus although it is soft and light.

[0002]

2. Description of the Related Art Conventionally, waterproof sheets having synthetic fibers as constituent fibers have been widely used in large tents, hoods for vehicles, sheets for ships and tent warehouses. The waterproof sheet used for each of these uses is required to have high tensile strength and high tear strength in addition to waterproof performance, and moreover, lightness is strongly desired as a recent market need.

However, conventional synthetic fibers have low tensile strength even with high-strength multifilaments for industrial materials, and in order to obtain the required strength for designing a waterproof sheet, the amount of yarn of the base cloth of the waterproof sheet must be adjusted. There is no choice but to increase the weight, and sufficient weight cannot be obtained. In order to obtain sufficient lightness, it is necessary to reduce the amount of yarn in the base cloth, and in this case, on the contrary, there is a drawback that the required strength for designing the waterproof sheet cannot be obtained. Further, the tear strength of the waterproof sheet is highly dependent on the tensile strength of the fibers used for the base cloth, and in order to obtain high tear strength, it is necessary to use high strength fibers for the constituent fibers of the base cloth. However, the conventional ones did not have sufficient tear strength.

Further, in applications such as large tents that are handled as a constituent material of a building, it is preferable that the waterproof sheet has a higher elastic modulus. However, the conventional one has a low elastic modulus and therefore has a high elastic modulus by design. Waterproof rate if required
Conventional synthetic fibers have not been used as the constituent fibers of glass, but special fibers such as glass fibers or aramid fibers have been used.

Among synthetic fibers, it has been proposed to use polyvinyl alcohol fiber having improved mechanical strength.
Since the fibers are produced by the solution spinning method, it is difficult to control in terms of productivity such as uniformity of the spinning dope and sticking between single yarns in the drying step.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to provide a waterproof sheet having high strength, high tear strength, high elastic modulus, which is soft and light, and which is simple in process. To provide.

The present invention has the above-mentioned object of being constituted by a polymer filament substantially consisting of a repeating unit represented by the following general formula (1), and the relationship between the weave density and the total fineness of the warp and the weft is as follows. A waterproof sheet comprising a woven fabric satisfying the formula (2) and at least one surface of which is coated with a thermoplastic resin or rubber.

Embedded image 900 ≧ weave density (books / inch) × √ total fineness ≧ 400 (2)

The constituent fibers of the waterproof sheet according to the present invention are
The polymer comprises a polymer represented by the above general formula (1), and the polymer is a copolymer in which CO units in the polymer are substantially arranged alternately with olefin-derived units. That is, it has a structure in which one olefin unit such as ethylene is located next to each CO unit in the polymer chain. The copolymer may be a true copolymer of carbon monoxide and one particular olefin, or alternatively a copolymer of carbon monoxide and two or more olefins.

The olefinic monomers which can be used in the polymer represented by the general formula (1) include ethylene, propylene, butene, pentene, hexene, heptene, octene, nonene, decene, dodecene, styrene,
Examples include methyl acrylate, methyl methacrylate, vinyl acetate, undecenoic acid, undecenol, 6-chlorohexene, N-vinylpyrrolidone, and diethyl ester of sulnylphosphonic acid, but mainly ethylene from the viewpoint of mechanical properties and heat resistance. Are preferred.

When ethylene and an olefin other than ethylene are used in combination, the molar ratio of ethylene to an olefin other than ethylene is preferably 4/1 or more. When it is less than 4/1, the melting point of the polymer is 200 ° C. or lower, and the heat resistance may be insufficient. From the viewpoint of the crystallinity of the polymer, the heat resistance, and the mechanical performance of the polymer filament obtained from the polymer, the molar ratio of ethylene to other olefinic monomer is more preferably 8/1 or more. In the present invention, the use of other known ethylene / CO copolymers having no alternating structure, which are produced using free-radical catalysts, is not considered.

The degree of polymerization of the copolymer used in the present invention is
Solution viscosity (LVN) measured at 60 ° C in m-cresol
Is preferably in the range of 1.0 to 10.0 dl / g. If the LVN is less than 1.0 dl / g, the resulting filament and the final product, the waterproof sheet, may have insufficient mechanical strength, and is preferably 1.2 dl / g or more. On the other hand, if it exceeds 10.0 dl / g, the melt viscosity and the solution viscosity at the time of fiberizing may become too high, resulting in poor spinnability. From the viewpoint of fiberization processability and mechanical properties of the obtained waterproof sheet, LVN is 1.3 to.
More preferably, it is within the range of 4.0 dl / g.

The method of forming the fiber made of the above-mentioned copolymer is not particularly limited, but a melt spinning method or a solution spinning method is generally adopted. When the melt-spinning method is adopted, the polymer is melt-spun at a temperature of at least (T + 20) ° C., preferably (T + 40) ° C., and then at the maximum (T-
The desired fiber can be easily produced by a method of stretching at a temperature of 10) ° C., preferably (T-40) ° C., preferably a draw ratio of 3 times or more, more preferably a draw ratio of 7 times or more (where T is It is the crystalline melting point of the polymer).

When the solution spinning method is adopted, the polymer is treated with, for example, hexafluoroisopropanol, m-, according to the method described in JP-A-2-112413.
Cresol etc. 0.25 to 20%, preferably 0.5
Dissolve at a concentration of -10%, extrude from a spinning nozzle to form fibers, and then remove and wash the solvent in a non-solvent bath of toluene, ethanol, isopropanol, n-hexane, isooctane, acetone, methyl ethyl ketone, etc., preferably an acetone bath. To obtain a spun raw yarn, and further (T-1
00) to (T + 10) ° C, preferably (T-50) to T
It can be stretched at 0 ° C. to finally obtain the desired fibers, where T is the crystalline melting point of the polymer.

As described above, the above-mentioned copolymer can be formed into fibers by either the melt spinning method or the solution spinning method, but the melt spinning method is effective in terms of productivity.

The fibers (filaments) obtained by the above method have a total fineness of 500 denier or more, a tensile strength of 8.0 g / denier or more and an initial elastic modulus of 100 g / denier or more. .

The waterproof sheet of the present invention has such a fiber content of 50 to 50 g under a twisting tension of, for example, 0.5 g / denier or less.
After adding a twist of 200 T / m, at least one surface of a base fabric formed by weaving the warp yarn and the weft yarn is coated with a thermoplastic resin or rubber. It is necessary that the base fabric is composed of the above-mentioned fibers having a total fineness of 500 denier or more, and that the relationship between the weave density and the fineness is such that both the warp and the weft satisfy the following formula (2). Is. 900 ≧ weave density (books / inch) × √ total fineness ≧ 400 (2)

When the total fineness of the fibers used for the warp and weft of the woven fabric is less than 500 denier, if the above formula (2) is satisfied, the mesh of the woven fabric becomes too small, and therefore the thermoplastic resin to be coated is used. The adhesion with the layer or the rubber layer is reduced, that is, the anchor effect of the coating layer due to the openings is reduced, and the strength required for the waterproof sheet is not satisfied.

Even when the relationship between the woven density and the total fineness exceeds the above formula (2), the opening of the woven fabric becomes too small and the anchoring effect at the time of processing the resin or rubber is not exhibited, so that the adhesive force is used. In addition to being unbearable, the initial strength of the sheet becomes too large, while the elongation becomes small, resulting in poor fitability to the laying surface. On the other hand, if it is less than the above formula (2), the weaving easily occurs during weaving, the reinforcing effect of the waterproof sheet becomes insufficient, and the tear resistance deteriorates.

The thermoplastic resin or rubber coated on at least one surface of the above-mentioned base cloth is vinyl chloride resin, polyethylene resin, chlorinated polyethylene, polyethylene ester elastomer, polyvinyl acetate, polyacrylic ester, urethane rubber, Although any material such as natural rubber may be used, vinyl chloride resin is preferable in terms of cost.

As a waterproofing method using these thermoplastic resins or rubbers, a coating method of coating the thermoplastic resin or rubber in the state of a fluid solution and heating and drying, or a thermoplastic resin or rubber is used. Dipping the base cloth in the plastisol solution and gelating the resin or rubber by heat treatment, dipping method, topping method in which the melt of thermoplastic resin or rubber is heat-sealed to the surface of the base cloth, or thermoplastic resin or rubber Examples thereof include a method of laminating films, and these methods may be a combination of two or more kinds. The thickness of the coating layer is preferably in the range of 1 to 5 mm as the sheet thickness from the viewpoint of the strength and handleability of the obtained sheet.

The waterproof sheet of the present invention has a high strength and a high tear strength, a high initial elastic modulus, and a small dimensional change due to an external force. Further, since a woven fabric having a specific weaving density is used as the base fabric, the opening of the base fabric is in an appropriate range, and as a result, the coating layer has an increased adhesion to the base fabric due to the anchor effect. The breaking strength of the waterproof sheet is improved. The waterproof sheet of the present invention has the excellent characteristics as described above, and can be effectively used for large tents, vehicle hoods, ship sheets, tent warehouses, and the like.

[0022]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples. Various physical properties in the examples are values measured by the following methods. (1) Solution Viscosity of Polymer (LVN) The polymer was dissolved in m-cresol at a concentration of 0.5 g / dl and measured at 60 ° C. using an Ubbelohde viscometer. (2) Tensile strength (g / denier) and initial elastic modulus (g / denier) of fiber Measured by a method according to JIS L1013. (3) Evaluation of waterproof sheet The waterproof sheet is laid in a plate frame having a height of 1 m square and 1 m,
Sand was packed in the plate frame to a height of 1 m, and after 1 week, the plate frame and sand were removed to evaluate the condition of the waterproof sheet. Evaluation criteria: ○: No damage △: Slight cracks occurred, but no problem in practical use ×: Large cracks occurred

Example An ethylene / propylene / carbon monoxide polymer (LVN 1.7 dl / g) obtained by copolymerizing 7 mol% of propylene was spun at a spinning temperature of 275 ° C., then stretched 6 times at a plate temperature of 200 ° C., and then heat-treated. The fiber was fixed and a total fineness of 500 to 5000 denier was obtained. The tensile strength and initial elastic modulus of the fiber are shown in the table below. The fiber is used as a warp and a weft with a twist of 100 T / m under a twisting tension of 0.3 g / denier.
Plain weaves were woven by changing the woven density so that the product of the woven density and the fineness was as shown in the table below. Using this woven fabric as a base fabric, a vinyl chloride resin layer having a thickness of 0.5 mm was topped on both sides to obtain a waterproof sheet.

[0024]

[Table 1]

[0025]

The waterproof sheet of the present invention is derived from the fact that the fibers constituting the sheet have high tensile strength and high initial elastic modulus. Have a rate,
Further, since the base cloth has a specific weaving density, the opening of the base cloth is in an appropriate range, the adhesiveness of the coating layer due to the anchor effect is increased, and the breaking strength of the sheet is improved. Therefore, it becomes excellent in tear resistance.

Claims (1)

[Claims] 1. A polymer filament consisting essentially of a repeating unit represented by the following general formula (1), wherein the relationship between the weave density and the total fineness of each of the warp and the weft satisfies the following formula (2). A waterproof sheet comprising a woven fabric coated with a thermoplastic resin or rubber on at least one side thereof. Embedded image 900 ≧ weave density (books / inch) × √ total fineness ≧ 400 (2)