JP2680895B2 - Membrane structure material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a film structure material having a glass cloth as a base material.

(Prior Art) In recent years, examples of applying an air film structure or a tension structure to a roof of a building such as a baseball field, a gymnasium, and the like are increasing.

These air film structure and tension structure are described in (a)-
It has the characteristics as shown in (c).

(A) The roof weight is small and a large span structure is possible.

(B) Since it has a light-transmitting property, it does not require artificial irradiation during the daytime, and the transmitted light becomes soft without shadows, and it is possible to create a completely new indoor space that is outside.

(C) The construction period required for roof construction work can be shortened.

And, as such a membrane structure material for the roof, a silicone resin layer, a polytetrafluoroethylene (hereinafter referred to as PTFE) layer, a glass bead-containing PT on the surface of the glass cloth.
It is known that a FE layer is sequentially formed, and a fluororesin dispersion is applied and dried thereon to form a fluororesin thin layer (Japanese Patent Publication No. 55-7148).

(Problems to be Solved by the Invention) By the way, when the roof is made of the above-mentioned membrane structure material, snowfall in winter is inevitable in northern countries. It is considered that this is because the surface of the thin fluororesin layer (due to the coating and drying of the fluororesin dispersion) as the outermost layer of the film structure material is not smooth enough to allow the sliding of the falling snow. Therefore, no effective means for preventing snow accumulation by a single membrane has been obtained at present.

For this reason, a method of avoiding snow accumulation by double spreading the film structure material and sending out hot air between the films to melt the snow has been studied, but there is a decrease in light transmittance, material cost and construction cost. Various problems have been pointed out such as increase and burden of hot air delivery cost.

It is therefore an object of the present invention to provide a snow cover avoidance means with a single membrane.

(Means for Solving the Problem) In order to solve the above problems of the prior art, the present inventor does not form the outermost layer of the film structure material by coating and drying a fluororesin dispersion, but forms a preformed fluorine. It was found that the use of a resin film makes it possible to avoid winter accumulation very effectively, and completed the present invention.

That is, the film structure material according to the present invention contains a silicone resin, a PTFE layer and glass beads on the surface of the glass cloth.
A PTFE layer is sequentially formed, and a fluororesin film is further fixed on the glass bead-containing PTFE layer.

Hereinafter, examples of the present invention will be described with reference to the drawings.
In the drawing, reference numeral 1 is a glass cloth as a base material in a film structure material, and a silicone resin layer 2 is formed in a thin layer on the surface thereof.

When a silicone resin layer is provided on the surface of the glass cloth, the glass cloth is impregnated with a silicone resin, and the small voids existing in the weave of the glass fiber forming the glass cloth are closed by the resin to improve the strength. It is preferable for improving water resistance.

It has been found that commercially available glass cloth usually has a sizing agent attached thereto, and that this sizing agent can be an impeding factor for impregnation of the silicone resin. Therefore, in the present invention, it is preferable that the sizing agent is incinerated and removed by exposing the glass cloth to a high temperature of about 350 ° C. or higher prior to the impregnation with the silicone resin.

As for the silicone resin, its emulsion and dispersion are commercially available from Shin-Etsu Chemical Co., Ltd., Toray Silicone Co., Ltd., Dow Corning, etc., and these can also be used.

When the glass cloth is impregnated with a silicone resin and a thin layer is formed on the surface of the glass cloth, the adhesion of the silicone resin increases, but the flexibility of the obtained film structure material increases, but the adhesion between the glass cloth and the silicone resin It was found that the force is reduced and delamination may occur due to the action of mechanical stress. On the other hand, when the adhesion amount of the silicone resin decreases, the obtained film structure material becomes hard,
It has also been found that fabric can be broken or cracked.

Accordingly, in the present invention typically from about 10 g / m ² or less amount of adhesion to the glass cloth of the silicone resin, preferably about 4-6 g / m ^2.

Further, as the PTFE for forming the PTFE layer 3 formed on the silicone resin layer 2, the conventionally used molecular weight of 2 ×
A powder of 10 ⁶ or less can be used, but a molecular weight of 3 × 10 ⁶ to 4 from the viewpoint of coating film strength and adhesion with silicone resin.
It is more preferable to use the one having × 10 ⁶ . In addition, this P
The adhesion amount of the TFE layer 3 is not particularly limited, but is usually 100 to 600 g / m ² .

In the present invention, the glass bead-containing PTFE layer 4 is further formed on the PTFE layer 3.

The layer 4 is formed of a composition containing both glass beads and PTFE as essential components so that the amount of adhesion is usually 100 to 500 g / m ² . The blending ratio of both is the film strength, PTFE
Considering the adhesion to the layer 3 and the dispersibility of PTFE and glass beads, it was found that the glass beads are preferably 1 to 5 parts by weight with respect to 100 parts by weight of PTFE.

The glass beads used for forming this layer 4 may be hollow or solid, and the spherical diameter thereof is usually about 1 to 50 μm.

In addition, the PTFE forming the PTFE layer 4 containing the glass beads
May be a low molecular weight powder having a molecular weight of 2 × 10 ⁶ or less like the PTFE layer 3, but a high molecular weight powder having a molecular weight of 3 × 10 ⁶ to 4 × 10 ⁶ is used from the viewpoint of coating film strength and the like. Is preferred.

In the present invention, the fluororesin film 5 is fixed on at least one of the glass bead-containing PTFE layers. This film includes PTFE, tetrafluoroethylene-hexafluoropropylene copolymer (hereinafter referred to as FEP
), A tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (hereinafter referred to as PFA), an ethylene-tetrafluoroethylene copolymer, and the like. The thinner the fluororesin film is, the better it is from the viewpoint of light transmittance, but if it is too thin, the mechanical strength will decrease,
From these balances, it is usually about 50 to 200 μm.

The glass bead-containing PTFE layer and the fluororesin film can be fixed to each other by a method of adhering both with an adhesive, a method of directly heat-sealing both without using an adhesive, etc., but from the viewpoint of weather resistance. Is preferably a method using no adhesive.

Since the membrane structure material shown in the above example has a fluororesin film adhered only to one of the glass bead-containing PTFE layers, when constructing a roof using this, the fluororesin film should be the outside and the surface smoothness of this film should be Use it to slide off snow to prevent snow accumulation. Of course, the fluororesin film can be fixed to both the glass bead-containing PTFE layers.

(Examples) Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1 A glass cloth is heated at 350 ° C. for 150 seconds to remove sizing agents and foreign substances.

This glass cloth is immersed in an emulsion having a silicone resin concentration of 3% by weight and pulled up, and heated at 290 ° C. for 150 seconds to impregnate the glass cloth with the silicone resin and form a silicone resin layer on the surface thereof. The amount of silicone resin adhered to the glass cloth at this time was 5 g / m.
²

Next, a dispersion having a PTFE powder concentration of 60% by weight is applied onto the silicone resin layer and heated at 360 ° C. for 3 minutes.
Further, the application of the dispersion and the heating are repeated once more to form a PTFE layer having a PTFE adhesion amount of 350 g / m ² .

Next, PT the PTFE dispersion containing glass beads.
Apply on FE layer and heat at 360 ° C for 3 minutes. Then, this coating and heating are repeated once more to form a glass bead-containing PTFE layer having an adhesion amount of 200 g / m ² .

The PTFE dispersion containing glass beads has a solid content (PTFE, glass beads) concentration of 50% by weight, and the mixing ratio of PTFE and glass beads (sphere diameter 10 to 15 μm) is PTFE100.
3 parts by weight of the glass beads with respect to parts by weight.

Then, on one of the glass beads containing PTFE layer, a thickness of 100
Put a PTFE film of μm, temperature 360 ℃, pressure 0.4kg / cm ²
By heating and pressurizing for 1 minute under the above conditions, the PTFE film was heat-sealed to obtain a membrane structure material having the same structure as the drawing.

Example 2 The same operation as in Example 1 except that a PFA film having a thickness of 125 μm was used in place of the PTFE film, and the heat-sealing conditions were a temperature of 330 ° C., a pressure of 0.4 kg / cm, and a heating and pressing time of 1 minute. Then, a film structure material was obtained.

Example 3 The same as Example 1 except that a 125 μm thick FEP film was used in place of the PTFE film, and the heat fusion conditions were a temperature of 290 ° C., a pressure of 0.4 kg / cm ² , and a heating and pressing time of 1 minute. Working to obtain the membrane structure material.

Comparative Example Example 1 except that a dispersion having an FEP powder concentration of 33% by weight was applied onto a glass bead-containing PTFE layer and heated at a temperature of 350 ° C. for 3 minutes to form an FEP layer (adhesion amount: 10 g / m ² ). The same operation as above was performed to obtain a film structure material.

The film structure materials obtained in these Examples and Comparative Examples were subjected to a characteristic test in the following manner, and the obtained results are shown in Table 1.

〔Surface roughness〕

The surface roughness of the membrane structure material (the surface roughness of the fluororesin film in the example, the surface roughness of the FEP layer in the comparative example) was measured by a surface roughness meter (Tokyo Seimitsu Co., Ltd., trade name Surfcom 550A). .

(Light transmittance)

The film structure material was heated at 382 ° C. for 16 hours, cooled to room temperature, and the transmittance in the visible light region of 380 to 760 nm was measured by a spectrophotometer.

〔Weatherability〕

Membrane structural material 2000 for sunshine weatherometer
After being charged for a period of time, taken out, the tensile strength was measured, and this value was divided by the value before charging to obtain the tensile strength retention rate (%).

The tensile strength is 25 ° C and the pulling speed is 200mm / min.
It was measured by a universal tensile type tester under the conditions of.

(Effects of the Invention) The present invention is configured as described above, and by using the fluororesin film as the outermost layer of the membrane structure material, the surface can be made smooth, and snow can be effectively prevented even in the winter of snowy countries. obtain.

[Brief description of the drawings]

The drawing is a front view showing an example of the film structure material according to the present invention. 1 ... Glass cloth, 2 ... Silicone resin layer 3 ... PTFE layer, 4 ... PTFE layer containing glass beads 5 ... Fluororesin film

Claims (1)

(57) [Claims] 1. A silicone resin layer, a polytetrafluoroethylene layer, and a glass bead-containing polytetrafluoroethylene layer are sequentially formed on the surface of a glass cloth, and fluorine is further provided on the glass bead-containing polytetrafluoroethylene layer. Membrane structural material made of resin film adhered.