JPS6147867A - Sealing of stitched part - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for sealing a sewn part of a sewn product made of a moisture-permeable waterproof material or the like.

Prior art and problems Materials with excellent moisture permeability and waterproofness, such as products made of laminates of polytetrafluoroethylene porous film and fabric (shoes, tents, windbreakers)
, raincoats, shorts, hats, etc.), it is necessary to make the sewn parts waterproof, and it is known to adhere a sealing sheet onto the sewn parts with an adhesive.

Traditionally, this type of sealing sheet has been made using rubber sheets or...
A plastic sheet coated with hot melt adhesive on one side is used.

Rubber-based sheets, such as those made of shikashina, have the disadvantage of being susceptible to residual distortion and tensile phenomena, while plastic sheets have disadvantages, such as poor ability to handle curves, lack of texture, and poor durability. be.

In view of the current situation, the present inventor conducted various experiments in order to develop an excellent sealing tape, and found that the Young's modulus of an unfired polytetrafluoroethylene porous tape significantly decreases when heated. Even if the tape is forced to follow the curve, and therefore the tape is distorted, the distortion can be easily removed by heating after adhesion.
I learned that it is possible to satisfy the curve compatibility described above.

Purpose of the Invention The present invention utilizes the characteristics of this unfired polytetrafluoroethylene porous tape to provide a seal that is excellent in terms of curve compatibility, workability, durability, and wind odor. The purpose is to provide a method.

Structure of the Invention The method for sealing a sewn part according to the present invention includes: - adhering a sealing tape formed by providing a pressure-sensitive adhesive layer to an axially stretched unfired polytetrafluoroethylene porous tape to the sewn part on the surface of the pressure-sensitive adhesive layer; This method is characterized in that the sealing tape is then subjected to a heat treatment.

In the present invention, the reason why heat treatment is performed after adhering the sealing tape to the sewn part is to eliminate the distortion that occurs in the unfired polytetrafluoroethylene porous tape due to forcing it to follow the curve of the sewn part. The objective is to remove the polytetrafluoroethylene porous material by lowering its Young's modulus, and the heating temperature is preferably in the range of 35 to 150°C. For this heating, a one-type heating roller welder or an ultrasonic welder can be used.

In the present invention, the reason why the unfired polytetrafluoroethylene porous tape is uniaxially stretched is that if the above-mentioned heat treatment is applied to an unstretched tape, cracks in the longitudinal direction of the tape often occur. The goal is to definitely eliminate it.

The green porous polytetrafluoroethylene tape has a specific gravity of 0.5 to 1.5, preferably 0.5 to 1.2.

If the specific gravity is less than 0.5, the strength will be insufficient.

If the specific gravity is 1.2 or more, the visibility of the sheet will decrease, the stitched parts will become strong, and it will be difficult to avoid deterioration of the texture.In addition, the degree of stretching will be low, and the above-mentioned longitudinal cracking of the tape under heating will be prevented. This makes oral changes more likely to occur.

The thickness of the sheet is usually 30-150μ.

As the pressure-sensitive adhesive, a pressure-sensitive water-resistant synthetic resin adhesive or a pressure-sensitive water-resistant rubber adhesive can be used. For example, acrylic pressure-sensitive adhesives made of partially cross-linked butyl acrylate-acrylic acid copolymers, silicone rubber-based adhesives, etc.
A fluororubber adhesive can be used.

The thickness of the adhesive layer is preferably 10 to 60 microns. If it is less than 10 μm, the adhesive strength is low, the water resistance and durability are poor, and the adhesive layer does not follow the uneven surface of the sewn portion unfavorably. If it is 60μ or more, the cohesive force decreases, and the adhesive tends to protrude from the edge of the -axially stretched unfired polytetrafluoroethylene porous tape, which is not preferable. In order to ensure cohesive force, a filler may be added in an amount of 30 parts or less.

In the present invention, as shown in FIG.
In order to seal the sewn portion according to the present invention by handling it in a temporarily attached manner, the separator is peeled off from the sealing tape, and this sealing tape is attached to the water-resistant pressure-sensitive adhesive layer 3 at the sewn portion A as shown in FIG. After that, the axially stretched unfired polytetrafluoroethylene porous tape 1 is heat-treated using a heated roller welder or an ultrasonic welder.

Description of examples Examples of the present invention will be described below in comparison with comparative examples.

Example A uniaxially stretched unfired polytetrafluoroethylene porous tape (specific gravity 0.8, thickness 80μ, width 18 m) was coated with butyl acrylate-acrylic acid copolymer (partially crosslinked) as the main component on one side. A pressure-sensitive adhesive (thickness: 30 μm) was applied, and a separator was temporarily attached to produce a sealing tape. While peeling off the separator, apply this seal tape using an ultrasonic welder (manufactured by Brother Industries, model Bu-5-1).
11) Place the upper part in contact with the sewn part of a sewn product made of Nitto Denko's waterproof material, trade name Microtex-2, and heat at 80°C x 5.
Heat treatment was performed under heating of ka~.

As a result of this heat treatment, the distortion of the uniaxially stretched unfired polytetrafluoroethylene porous tape that occurred during the above-mentioned contact completely disappeared. In addition, whether the sewn product after sealing treatment has been washed with water for 30 minutes 100 times, or the water resistance of the sewn part is the initial value (measured value according to JISL 1092, 6-720).
01 or higher) (when the same uniaxially stretched unfired polytetrafluoroethylene porous tape as above was used and bonded with a urethane hot melt adhesive, the water resistance decreased after washing 5 times with water). Further, after washing with water 100 times, the -axially stretched unfired polytetrafluoroethylene porous tape was closely observed, and no cracks or the like were found at all.

Effects of the Invention As described above, according to the present invention, a sewn portion can be sealed with excellent curve adaptability and washability, and is useful for sealing waterproof sewn products.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a sealing tape used in the present invention, and FIG. 2 is an explanatory diagram showing the present invention. In the figure, 1 is a uniaxially stretched unfired polytetrafluoroethylene porous tape, 2 is a pressure-sensitive adhesive layer, and A is a sewn portion. 11-1mi

Claims (1)

[Claims] A sealing tape made by providing a pressure-sensitive adhesive layer on a uniaxially stretched unfired polytetrafluoroethylene porous tape is adhered to the sewn portion on the surface of the pressure-sensitive adhesive layer, and then the sealing tape is heat-treated. How to seal the seams.