JPH08308402A - Heat-shielding screen and its production - Google Patents

Abstract

PURPOSE: To obtain a heat-shielding screen excellent in weatherability and capable of surely suppressing heat from direct solar light. CONSTITUTION: A heat-shielding screen is produced by laminating the first layer 21 comprising a biaxially oriented polyester film, the second layer 22 formed by vacuum-depositing aluminum on the first layer, and the third layer comprising a uniaxially oriented high density polyethylene film to one another in the order, cutting the formed three-layered film in the oriented direction of the third layer 23, and subsequently knitting or weaving the formed heat- shielding tapes 2. The thickness of the first layer 21 and the thickness of the second layer 23 are set to 10-30μm, respectively. The third layer 23 is laminated to the second layer 22 by a dry lamination method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat shield screen for protecting agricultural products and the like from radiant heat by blocking sunlight, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, an agricultural shading net disclosed in Japanese Utility Model Publication No. 5-33339 is known. This shading net is obtained by weaving a long and narrow tape (shading tape) having a shading function, which covers the surface of growing crops and blocks the strong direct sunlight of midsummer to adversely affect crops. Is to remove.

In the above publication, aluminum is vapor-deposited on a stretched high-density polyethylene film having a thickness of 5 to 50 μm, and an unstretched low-density polyethylene film having a thickness of 10 to 50 μm is laminated on the vapor-deposited layer to form three layers. It is described that the above-mentioned light-shielding tape can be obtained by producing a sheet having a structure and longitudinally splitting the sheet having a three-layer structure in the stretching direction of a high-density polyethylene film.

[0004]

By the way, polyethylene is apt to deteriorate when it is irradiated with ultraviolet rays, and therefore, its strength is remarkably lowered when it is left in the hot sun for a long time. In particular, a non-stretched low-density polyethylene film is used for the third layer of the tape used for the above-mentioned light-shielding net, and such a polyethylene film is inferior in strength and weather resistance, and therefore, when it is left outdoors for a long time. Deterioration of the third layer is remarkable,
As a result, the peeling of the third layer proceeds promptly. Therefore, the light-shielding net described in the above publication in which unstretched low-density polyethylene is used as a part of the material is, depending on atmospheric conditions,
There is a problem that it deteriorates to the extent that it cannot be reused even after being used for a summer, and eventually it can be used only as a disposable product, which is economically disadvantageous.

Further, when the aluminum of the second layer is exposed to the atmosphere due to the peeling of the third layer, it is oxidized and becomes transparent aluminum oxide, so that there is a problem that the light shielding effect is impaired. are doing.

Furthermore, since polyethylene has a poor heat shielding property, for example, it transmits about 75% of the far infrared rays irradiated, the second
When the layer becomes a transparent aluminum oxide layer, far infrared rays transmitted through the polyethylene of the first layer will be directly radiated to the agricultural products, and as a result, the agricultural products covered with the light shielding net will be surely prevented from becoming high temperature. It has a problem that it cannot be done.

The present invention has been made in order to solve the above problems, is excellent in weather resistance, and is capable of reliably suppressing heat from direct sunlight, and its manufacture. It is intended to provide a way.

[0008]

A heat shield screen according to claim 1 of the present invention is formed by a first layer made of a biaxially stretched polyester film and aluminum vapor-deposited on the first layer. A film having a three-layer structure is formed by the second layer composed of the vapor-deposited aluminum vapor deposition layer and the third layer composed of the uniaxially stretched high-density polyethylene film laminated on the second layer. A tape is formed by cutting the third layer in the stretching direction, and a screen having heat shielding properties is formed by knitting or weaving using the tape.

The heat shield screen according to claim 2 of the present invention is the heat shield screen according to claim 1, wherein
The layer and the third layer each have a thickness of 10 to 30 μm.
It is characterized by being set to.

According to a third aspect of the present invention, there is provided a heat shield screen manufacturing method, wherein aluminum is vapor-deposited on a first layer of a biaxially stretched polyester film to form a second layer. A film having a three-layer structure is formed by laminating a third layer made of a high-density polyethylene film that has been subjected to a uniaxial stretching treatment to two layers, and the film is cut in the stretching direction of the third layer to form a tape. Then, a screen having a heat shielding property is knitted or woven using this tape.

A method for manufacturing a heat shield screen according to a fourth aspect of the present invention is the method for manufacturing a heat shield screen according to the third aspect, wherein the third layer is laminated on the second layer by a dry laminating method. It is characterized by.

[0012]

According to the heat shield screen and the method of manufacturing the same of the above claims 1 and 3, the sunlight is radiated to the aluminum by blocking the direct sunlight irradiating the object to be shielded such as growing agricultural products with the heat shield screen. Since it is reflected by the vapor-deposited second layer, the sunlight is not directly applied to the shielded object but is shielded from heat, thereby preventing an excessive temperature rise of the shielded object.

Since the polyester film of the first layer and the high-density polyethylene film of the third layer are excellent in weather resistance and toughness, the heat shield screen is exposed to direct sunlight for a long period in the field. Also, damage due to deterioration of the first layer and the third layer is unlikely to occur, and as a result, the aluminum of the second layer sandwiched between the first layer and the third layer is directly exposed to air and oxidized, resulting in transparent oxidation. Aluminum is suppressed for a long time.

Further, since polyester is excellent in heat resistance, it does not easily soften even when the first layer is exposed to the direct sunlight of midsummer to reach a high temperature, and therefore the aluminum deposited on the first layer is peeled off. Is unlikely to occur. Furthermore, the polyester of the first layer almost absorbs far infrared rays in the sun rays, and is about 1
Since only 0% is transmitted, this suppresses the temperature rise of the coating, even if aluminum flakes occur.

According to the heat shield screen of the second aspect, the thickness of the first layer and the third layer is set to 10 to 30 μm, and the second layer (aluminum vapor deposition layer) can be ignored. Since the thickness of the shielding screen is about the same, the thickness of the tape constituting the shielding screen is as thin as 20 to 60 μm, which makes the shielding screen very light.

According to the method for manufacturing a heat shield screen of the fourth aspect, since the third layer is laminated on the second layer by the dry laminating method, the laminating operation is easy.
And the laminated state is reliably maintained.

[0017]

1 is a partial plan view showing an example of a heat shield screen according to the present invention. As shown in this figure, in this embodiment, the heat shield tape 2 is used as the weft, and the normal synthetic resin wire 3 is used as the warp, and these are plain-woven, leno-woven, or A heat shield screen (screen having heat shield properties) 1 is formed by weaving with another weave design. The heat shield tape 2 has a thickness of 0.1 mm and a width of 3 mm, and the synthetic resin wire 3 is a thin wire having a diameter of about 0.2 mm. The size of the gap 11 formed between the wefts and extending in the horizontal direction is set to 2 mm, whereby the porosity of the heat shield screen 1 is 40%.

The heat shield tape 2 and the synthetic resin wire 3
The dimensions of the gap 11 and the gap 11 are not limited to the above numerical values, and can be arbitrarily set depending on the heat shield property of the heat shield screen 1, the target of coating, and the like. Alternatively, heat shield tapes may be used for both the weft yarns and the warp yarns, and the heat shield screen may be formed by the heat shield tapes woven in the longitudinal and transverse directions. This makes it possible to reduce the porosity of the heat shield screen. Furthermore, by knitting the heat shield tape 2 using a Raschel warp knitting machine or the like, it is possible to obtain a heat shield screen having high elasticity.

FIG. 2 is a sectional view showing the heat shield tape.
As shown in this figure, the heat shield tape 2 includes a first layer 21 and
The second layer 22 is laminated on the first layer 21, and the third layer 23 is further laminated on the second layer 22 to form a three-layer structure. The first layer 21 is formed of a biaxially stretched polyester film, the second layer 22 is formed of an aluminum vapor deposition layer deposited on one side of the polyester film, and the third layer 23 is laminated on the aluminum vapor deposition layer. It is formed of a high-density polyethylene film that has been subjected to a uniaxial stretching process.

The above polyester film is made of unsaturated polyester resin, alkyd resin,
Those made of polyarylate, those made of polyethylene terephthalate, and the like can be used. In this embodiment, a polyethylene terephthalate film is used.

The thickness of each of the first layer 21 and the third layer 23 is set to 10 to 30 μm. Further, the second layer (aluminum vapor deposition layer) 22 has a size of several Å to several tens of
A predetermined thickness is set within the range, and the light transmittance of the heat shield tape 2 is adjusted by this thickness setting.

Such a heat shield screen 1 is manufactured as follows. First, a polyester film is biaxially stretched to produce a biaxially stretched polyester film for the first layer 21, which has improved longitudinal and transverse tensile strength. The second layer 22 is formed by vapor-depositing aluminum on one surface of this polyester film by a conventional method.

A third layer 23 is formed by laminating a high-density polyethylene film that has been uniaxially stretched by a dry laminating method on the aluminum vapor deposition surface of the two-layer structure film having the second layer 22 formed thereon. The dry laminating method uses a polyurethane-based or isocyanate-based adhesive diluted with a solvent such as toluene, ethyl acetate, or hexane as an adhesive, which is applied to the laminated surface of one film and then dried with a drier. This is a method for producing a laminate in which the other film is laminated on the dried adhesive surface and pressed between the rolls. In this example, an adhesive is applied to the aluminum vapor deposition surface, dried, and a high-density polyethylene film is laminated thereon to produce a film having a three-layer structure.

Next, the heat-shielding tape 2 is obtained by cutting this three-layer structure film in a predetermined width in the stretching direction of the high-density polyethylene film. The heat shield tape 2 is used as a weft yarn, the synthetic resin wire rod 3 is used as the warp yarn, and these are woven by plain weave, whereby the heat shield screen 1 as shown in FIG. 1 is obtained.

According to the heat shield screen 1 having the above-mentioned structure, by covering the growing agricultural products, fruit trees, etc. with the heat shield screen 1, the direct sunlight is blocked by the heat shield screen 1, and thereby the heat shield screen 1 is irradiated. The sun's rays
Except for the light rays leaking from the gap 11 between the heat shield tapes 2, it is reflected by the second layer vapor-deposited of aluminum,
The amount of sunlight that is radiated to agricultural products is reduced, and excessive temperature rise of agricultural products is prevented.

Then, the first layer 2 constituting the heat shield tape 2
The polyester film of No. 1 is toughened by the biaxial stretching treatment, and the high-density polyethylene film of the third layer 23 is toughened by the uniaxial stretching treatment, and the polyester film and the high-density polyethylene film have excellent weather resistance. Even if the thermal screen 1 is exposed to the direct sunlight for a long time in the field, the damage due to the deterioration of the first layer 21 and the third layer 23 hardly occurs. Therefore, it is superior in durability to the conventional one using only polyethylene as a base material, and even if the heat shield screen 1 is used for one summer season, the heat shield screen 1 withstands reuse after the end of the season. It is extremely economical because it can withstand multiple seasons of use without the inconvenience of being damaged more than it should.

Even if the heat shield screen 1 is used for a plurality of seasons, the aluminum vapor deposition layer (second layer 22) held by the first layer 21 and the third layer 23 is directly exposed to air. The inconvenience of being oxidized and becoming transparent aluminum oxide is unlikely to occur, and the inconvenience of varying the transmittance of direct sunlight can be surely suppressed.

The heat-resistant temperature of polyethylene is 120 ° C.
On the other hand, as is clear from the fact that the heat resistance temperature of polyethylene terephthalate is as high as 150 ° C., polyester is inherently excellent in heat resistance, and therefore, the first layer (two layers The axially stretched polyester layer) 21 does not soften and deform even when the temperature rises, and therefore the first layer 21
The vapor deposition base material (first layer) of aluminum vapor-deposited on is stable. Therefore, the present invention using polyester as a base material has an advantage that the second layer 22, which is an aluminum vapor deposition layer, is less likely to be peeled off, as compared with a conventional polyethylene material used as a base material for aluminum vapor deposition. ing.

Further, polyester almost absorbs far infrared rays in sunlight (specifically, it absorbs far infrared rays having a wavelength of 8 to 10 μm) and transmits only about 10%, so that even aluminum is exfoliated. Even if direct sunlight passes through the polyester layer, the amount of far infrared rays transmitted is small, and the supply of heat to crops and the like is reliably suppressed. In addition, polyester absorbs UV rays with a wavelength of 300 nm or less, which adversely affects the growth of agricultural products.
The growth failure of agricultural products due to the irradiation of ultraviolet rays can be reliably eliminated.

Thus, the heat shield screen 1 of the present invention
Has an excellent heat shielding effect and an effect of blocking ultraviolet rays of harmful wavelengths, exerts a function of suppressing heat from direct sunlight in the daytime, suppresses heat radiation from the soil at night, and has a temperature difference between day and night. Since it is small, it is extremely useful for growing good agricultural products. The light-shielding screen of the present invention,
The invention is not limited to agricultural applications, but can be applied to any application that blocks radiant heat from direct sunlight, such as for shade formation at beaches and cover sheets for automobiles.

Test Example 1 In order to examine the heat shield effect of the heat shield screen 1 according to the present invention, a heat shield property confirmation test was carried out. FIG. 3 is a side cross-sectional view showing a test device used for the heat shield property confirmation test. As shown in this figure, the test apparatus 4 is composed of a plurality of support columns 41, a support base 42 arranged on the support columns 41, and a pair of black panels 43 supported by the support bases 42. ing. The test apparatus 4 is installed on the ground G in which the lawn is planted, and diffuses the direct sunlight that is applied by the lawn to suppress the influence of the reflected light from the ground G on the black panel 43 as much as possible. I am trying.

A pair of left and right sunlight introducing holes 44 are formed in the support base 42, and the black panel 43 is suspended below the sunlight introducing holes 44 by a string 45 so as to be horizontal. The upper surface of the black panel 43 is painted black,
We try to absorb all the sunlight that is applied.

The left sunlight introducing hole 44 is shielded by the heat shield screen 1 so that the black panel 43 is not exposed to sunlight except for the one inserted through the gap. The sunlight introducing hole 44 on the right side is not shielded by the heat shield screen. Temperature sensors 46 are arranged on the left and right black panels 43, and the temperature of each black panel 43 is measured by these temperature sensors 46.

The plane size of the black panel 43 is 7
cm × 14 cm, the plane size of the heat shield screen 1 is 30
It was set to cm × 30 cm. In addition, the support base 42
The distance between the bottom surface of the black panel 43 and the top surface of the black panel 43 was set to 5 cm.

Then, the test apparatus 4 is arranged on the ground G in consideration of fine weather in the daytime, and the left black panel 43 covered with the heat shield screen 1 and the right black panel 43 not covered with the heat shield screen 1 are arranged. The temperature of the black panel 43 was continuously measured by the temperature sensor 46 for 1 hour. The measurement results are shown in the graph of FIG.

In this graph, the horizontal axis indicates elapsed time (minutes),
The vertical axis represents the temperature (° C) of the black panel 43, and the solid line in the graph indicates the heat shield screen 1.
The temperature (blank temperature) of the black panel 43 not covered with is shown, and the temperature of the black panel 43 covered with the heat shield screen 1 is shown except for the solid line. And
The dotted line indicates the heat shield screen 1 (first sample) in which seven heat shield tapes 2 are arranged per inch (2.54 cm), and the dashed line indicates the ten heat shield screens 1 (second sample).
In addition, the two-dot chain line is the same 12 heat shield screens 1.
(3rd sample) is shown.

The first sample in which the heat shield tape was set to 7 pieces / inch was woven with the heat shield tape having a width of 3 mm maintaining the width as it was, but the second sample and the third sample In the sample, most of the heat shield tape was folded back in the width direction.

The other conditions in this test were as follows: Temperature sensor: Thermocouple type thermometer (DA
TA COLLECTOR AM-7052) Time: April Environmental temperature: 15 ° C Environmental humidity: 55% (relative humidity) Weather conditions: Sunny, sometimes cloudy Insolation: 151-636W / m ² Also, above the horizontal axis of the graph. The weather condition is "clear",
Divide into "cloudy weather" and fill in the weather and black panel 43
I try to understand the relationship with the temperature.

As can be seen from this graph, the temperature of the black panel 43 when it is covered with the heat shield screen 1 is about 4 as compared with the temperature when it is not covered (hereinafter referred to as blank).
It was confirmed that the temperature was lowered by -10 ° C, and the heat shield screen 1 was excellent in the heat shield effect. Also, in the case of sunny weather with a large amount of solar radiation, the temperature difference with the blank is large,
When it is cloudy, the temperature difference is small. This indicates that the heat shield screen 1 of the present invention has a great effect on strong solar radiation, and it was confirmed that the effect of suppressing the temperature rise of agricultural products and the like due to direct sunlight during fine weather was great.

Regarding the number of heat shield tapes arranged, it was confirmed that the heat shield effect was improved as the number of heat shield tapes was increased. It was also confirmed that the improvement of the heat shield effect was remarkable when the weather was fine.

(Test Example 2) In order to examine the light blocking rate of the heat blocking screen, the first sample (heat blocking tape, 7 / inch),
Second sample (10 / inch) and third sample (12 / inch)
Each of the books / inch) was placed outdoors during fine weather, and the illuminance (lux) of the upper part and the lower part of the heat shield screen was measured under the condition that they were exposed to direct sunlight. The measurement results are as shown in Table 1.

[0042]

[Table 1]

As can be seen from Table 1, the shading rate ((illuminance below the sample / illuminance above the sample) × 100) was 5 for the first sample.
4.5%, second sample 61.5%, third sample 67.4%
%, And it was confirmed that the light-shielding rate increased as the number of heat-shielding tapes per inch increased.

Test Example 3 In order to examine the durability of the heat shield screen according to the present invention, a weather resistance test was carried out in accordance with JIS L1096. The sample has a thickness of 0.1 mm,
A heat-shielding tape having a width of 3 mm and a length of about 200 mm was randomly selected, and both sides of the heat-shielding tape were held by the holding member in the sunshine weather meter. Gripping interval is 150 mm
Set to. Then, the sample was irradiated with light from a sunshine carbon arc lamp, and the sample was left in the rained state for 380 hours. Then, after 380 hours had passed, the gripping interval was expanded at a speed of 150 mm / min, and the elongation (%) until the heat shield tape was broken and the force required for the break (break strength (kgf)) were measured. The elongation and the breaking strength were also measured for the sample before exposure with a sunshine weather meter. As a comparative example, the same test was performed using a polyethylene tape having the same size as the above sample. The test results are shown in Table 2.

[0045]

[Table 2]

As can be seen from Table 2, the samples of the examples before exposure which were not subjected to the weather resistance test had a breaking strength of 3.03.
The sample of Comparative Example had a breaking strength of 2.52 kgf and an elongation of 44.3%, while the kgf and the elongation were 25.2%.
It was confirmed that the heat-shielding tape according to the present invention has a strength of about 20% higher than that of the heat-shielding tape of the comparative example, but is less likely to stretch than that of the comparative example.

After the exposure in the sunshine weather meter for 380 hours, the breaking strength of the heat shield tape of the example was 2.77 kgf and the elongation was 18.0%, and the retention rate ((exposure (Number after / number before exposure) x 1
No. 00) had a breaking strength of 91.4% and an elongation of 71.4%.

On the other hand, the heat shield tape of the comparative example has 3
After the exposure for 80 hours, the breaking strength was 2.14 kgf and the elongation was lowered to 21.5%, and the respective retention rates were 84.
6% and 48.5%, and those made of polyethylene have markedly reduced breaking strength and elongation after exposure for 380 hours in the sunshine weather meter, as compared with the examples. From this, it is understood that the heat shield screen according to the present invention is superior in weather resistance and durability as compared with the conventional one made of polyethylene.

[0049]

According to the heat shield screen and the method for producing the same according to claims 1 and 3 of the present invention, aluminum is vapor-deposited on the first layer of the biaxially stretched polyester film to form the second layer. A layer having a three-layer structure is formed by forming a layer and laminating a third layer made of a high-density polyethylene film that has been subjected to a uniaxial stretching treatment on the second layer. A tape is formed by cutting into a tape, and the tape is knitted or woven using the tape to form a heat shield screen. Therefore, the polyester film of the first layer and the high-density polyethylene film of the third layer have weather resistance and It has excellent toughness and is resistant to damage due to deterioration of the first and third layers even when exposed to direct sunlight for a long time outdoors in the heat shield screen. Result, the aluminum is exposed to surely be a transparent aluminum oxide blocking direct air, it is advantageous in maintaining a thermal barrier effect for a long period of time.

In particular, the polyester film is superior in heat resistance to the conventional polyethylene film, and does not easily soften even when exposed to direct sunlight in the midsummer to reach a high temperature. Therefore, the film is deformed due to the above softening. This does not cause the aluminum deposition base (first layer) to become unstable, and thus. The state of vapor deposition of aluminum is better than that of the conventional polyethylene film, and it is effective in suppressing peeling of the aluminum layer and eventually deterioration and damage of the tape.

Further, since the tape is formed by cutting the third layer of the three-layer structure sheet in the stretching direction, the tensile strength of the tape in the longitudinal direction is large, and the first layer is biaxially stretched. Combined with the increased strength in the vertical and horizontal directions, it is convenient for increasing the tensile strength of the heat shield screen.

Further, since the polyester of the first layer almost absorbs far infrared rays in sunlight and transmits only about 10%, even if the vapor deposition layer of aluminum peels off,
The temperature rise of the coating due to the heat shield screen is reliably suppressed.

According to the heat shield screen of claim 2 of the present invention, the first layer and the third layer are set to have a thickness of 10 to 30 μm, and the second layer (aluminum vapor deposition layer).
Is negligible, the thickness of the tape constituting the shielding screen is very thin, 20 to 60 μm,
The shield screen becomes very light, which is convenient for handling the shield screen.

According to the method of manufacturing a heat shield screen according to claim 4 of the present invention, since the third layer is laminated on the second layer by the dry laminating method, the laminating operation is easy and reliable. It is effective in maintaining the laminated state.

[Brief description of drawings]

FIG. 1 is a partial plan view showing an example of a heat shield screen according to the present invention.

FIG. 2 is a cross-sectional view showing a heat shield tape.

FIG. 3 is a sectional side view showing a test apparatus used for a heat shield property confirmation test.

4 shows the temperature of the black panel on the left side of FIG. 3 coated with a heat shield screen and the temperature of the black panel on the right side of FIG. 3 not coated with a heat shield screen continuously for 1 hour by a temperature sensor. It is a graph which shows the measured measurement result.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Heat shield screen (screen with heat shield property) 11 Gap 2 Heat shield tape 21 1st layer (biaxially stretched polyester film layer) 22 2nd layer (vapor deposition aluminum layer) 23 3rd layer (uniaxially stretched high density polyethylene film) Layer) 3 Synthetic resin wire 4 Test device 41 Support 42 Support stand 43 Black panel 44 Sunlight introduction hole 45 String 46 Temperature sensor

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location D03D 15/02 D03D 15/02 C

Claims (4)

[Claims] 1. A second layer comprising a first layer made of a biaxially stretched polyester film and an aluminum vapor deposition layer formed by vapor-depositing aluminum on the first layer.
A film having a three-layer structure is formed by a layer and a third layer composed of a high-density polyethylene film that has been subjected to uniaxial stretching processing and is laminated on the second layer, and the film is cut in the stretching direction of the third layer. The heat shield screen is characterized in that a screen having a heat shield property is formed by knitting or weaving the tape. 2. The heat shield screen according to claim 1, wherein each of the first layer and the third layer has a thickness of 10 to 30 μm. 3. A second layer formed by vapor-depositing aluminum on a first layer made of a biaxially stretched polyester film.
A layer having a three-layer structure is formed by forming a layer and laminating a third layer composed of a high-density polyethylene film subjected to uniaxial stretching treatment on the second layer. A method for producing a heat shield screen, which comprises cutting a tape to form a tape, and knitting or weaving a screen having a heat shield using the tape. 4. The method for manufacturing a heat shield screen according to claim 3, wherein the third layer is laminated on the second layer by a dry laminating method.