JPH05115239A - Horticultural sheet - Google Patents

Abstract

PURPOSE:To obtain the subject sheet having a reflection peak at a specified wavelength, excellent in pest-repelling effect, crop-growing effect and mechanical strength by laminating a nonwoven fabric with a resin composition comprising a thermoplastic resin and filler, followed by uniaxial or biaxial drawing at a specified draw ratio. CONSTITUTION:One side or both sides of a nonwoven fabric is laminated with a resin composition comprising (A) 100 pts.wt. of a thermoplastic resin such as low-density polyethylene or high-density polyethylene and (B) 50-400 pts.wt. of a filler, pref., having 0.8-10mum mean particle diameter such as calcium carbonate or zeolite, followed by drawing the laminate uniaxially or biaxially by a factor of 1.1-8.0, thus obtaining the objective sheet having a reflection peak at a wavelength of < 0.4mum with a reflection spectrum of >=40% reflectance at wavelengths of 0.4 to 0.8mum.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a horticultural sheet.
More specifically, the present invention relates to a horticultural sheet having excellent water vapor transmission control properties, which is excellent in pest repellent effect, crop growing effect and strength.

[0002]

2. Description of the Related Art Conventionally, as a mulching film for repelling harmful insects, there is a mulching film having a reflective property improved by a layer containing an inorganic compound in a resin as described in JP-A-62-265927. However, because the water vapor permeability could not be controlled, the water content in the soil could change greatly depending on the environment, which could adversely affect crop growth.
The publication also proposes providing a through hole having a hole diameter of 0.3 to 10 mmφ, but because the hole diameter is large, not only water vapor but also water is permeated to control the amount of water in the soil. It was not effective in the sense.

[0003]

[Means for Solving the Problems] The inventors of the present invention control the amount of water in soil by impermeable to water and permeating water vapor, and the pest repellent effect and crop growth effect by reflected light and high strength are achieved. I have been continuing my research on how to obtain the sheets that I have. As a result, they have found that the above problems can be solved by arranging a layer obtained by stretching a resin composition comprising a resin and a specific filler, and further arranging a non-woven fabric in the layer, thereby completing the present invention.

That is, according to the present invention, a resin composition comprising 100 parts by weight of a thermoplastic resin and 50 to 400 parts by weight of a filler is laminated on a non-woven fabric, and then uniaxially or biaxially 1.1-
The sheet obtained by stretching at a draw ratio of 8.0 has a reflection peak at a wavelength of less than 0.4 μm and a wavelength of 0.4 to
A horticultural sheet having a reflection spectrum showing a reflectance of 40% or more at 0.8 μm.

The thermoplastic resin used in the present invention is, for example, an α-olefin homopolymer such as low density polyethylene, high density polyethylene, polypropylene or polybutene, ethylene and at least one α-olefin having 3 to 18 carbon atoms.
Organic carboxylic acid derivatives having ethylenically unsaturated bonds such as copolymers with olefins, propylene with ethylene and / or butene-1, ethylene with vinyl acetate and / or acrylic acid esters / methacrylic acid esters And copolymers thereof. In particular, a copolymer of ethylene and at least one α-olefin having 3 to 8 carbon atoms is preferable from the viewpoint of strength at the time of compounding the filler,
Furthermore, low density polyethylene, ethylene and carbon number 3-8
From the viewpoint of film processability and stretchability, a blend of a copolymer with at least one α-olefin is preferable.

In the present invention, when the amount of the filler is less than 50 parts by weight with respect to 100 parts by weight of the thermoplastic resin, it is difficult to exhibit the water vapor permeation controllability, and when it exceeds 400 parts by weight, the workability is increased. Is not preferable because it deteriorates. In particular, the filler is 70 to 20 from the viewpoint of processing stability.
0 parts by weight is preferred.

The water vapor permeability of the horticultural sheet according to the present invention is 500 to 200 according to the measuring method of JIS Z-0208.
A range of 00 g / m ² · day is preferable.

Examples of the filler include carbonates such as calcium carbonate, magnesium carbonate and barium carbonate, sulfates such as barium sulfate, magnesium sulfate and calcium sulfate,
Phosphates such as magnesium phosphate and calcium phosphate, hydroxides such as magnesium hydroxide and aluminum hydroxide, alumina, silica, oxides such as magnesium oxide, calcium oxide, zinc oxide and titanium oxide, aluminum powder, zeolite, and shirasu Inorganic fillers such as white clay, diatomaceous earth, talc and volcanic ash, and cellulosic powders such as wood powder and pulp powder, nylon powder, polycarbonate powder, polypropylene powder, poly-4-methylpentene-
There may be mentioned synthetic resin powders such as 1 powder and organic fillers such as starch, which may be used alone or in combination. The average particle size of the filler is 0.1 to 20 μm.
m is preferable from the viewpoint of film uniformity due to dispersion of the filler, and particularly preferably 0.8 to 10 μm from the viewpoint of processability.

In the horticultural sheet of the present invention, the wavelength of 0.
Having a reflection peak below 4 μm is the result of various studies as a result of various repellent effects against crop pests such as aphids and thrips as a result of a wavelength of 0.4
This is because a film showing a spectrum having a reflection peak below μm is effective in controlling pests. Especially, wavelength 0.4
It is extremely effective for pest repellent that the ratio RA / RB of the ultraviolet ray reflectance RA of less than μm and the visible ray reflectance RB of wavelength 0.5 μm is 1.4 or more.

Further, it has a reflection spectrum showing a reflectance of 40% or more at a wavelength of 0.4 to 0.8 μm.
This is because the crop cultivation effect by reflected light is exhibited. In particular, 1 to 30% by weight of the filler is a titanate compound and / or a pest repellent effect and a crop-growing effect.
Alternatively, it is preferably a zirconium compound.

The horticultural sheet of the present invention is obtained by laminating a resin composition exhibiting water vapor transmission controllability and reflection characteristics on one or both sides of a breathable nonwoven fabric, and then stretching it uniaxially or biaxially with the nonwoven fabric. Obtainable. A film without a non-woven fabric is not preferable because the strength of the film is reduced, and when the non-woven fabric is bonded partially or entirely with heat or an adhesive resin, the film and the non-woven fabric do not peel off or exhibit moisture permeability. It is not preferable because

The thickness of the nonwoven fabric is preferably 10 to 400 μm, and if it is less than 10 μm, the strength after stretching cannot be expected,
When it exceeds 400 μm, the stretchability is deteriorated, which is not preferable.

In the method of melt-laminating on the nonwoven fabric of the present invention and then stretching simultaneously with the nonwoven fabric, if the adhesive strength between the resin composition and the nonwoven fabric is not high, the resin composition may be peeled off at the time of stretching, so that the nonwoven fabric is higher than 40 ° C. A material containing at least one low melting point resin component having a melting point lower than the melting laminating temperature of the resin composition by 50 ° C. or more is used. Examples of such a non-woven fabric include a non-woven fabric composed of a single resin component to which the low melting point resin component is adhered by solution immersion, a product obtained by mixing two or more types of resin components into fibers, and a fiber. An example of the nonwoven fabric is a mixture of two or more resin components. Examples of the fibers mixed with two or more kinds of resin components include, for example, a concentric multi-layer type including a core layer and a sheath layer, or a multi-layer type in which each resin is eccentric and part or all of the sheath layer is the low melting point resin. And a part of the fiber is at least the low melting point resin, which is continuously or intermittently present on the surface of the fiber. In particular, from the viewpoint of strength of the non-woven fabric, a non-woven fabric composed of fibers having a core layer and a sheath layer, and at least the outermost sheath layer comprising a low melting point resin component is preferable.

When the difference between the melt laminating temperature and the melting point of the resin component constituting a part or the whole of the nonwoven fabric is less than 50 ° C., the adhesive strength during melt lamination is not good, which is not preferable, and the melting point of the resin component is less than 40 ° C. In the case of film processing especially in the summer, the tackiness of the film greatly increases,
It is not preferable because the roll separation becomes bad and causes troubles.

Examples of the resin component constituting a part or the whole of the nonwoven fabric include polyester, nylon, α-olefin homopolymers such as polyethylene, polypropylene and polybutene, and ethylene and at least one α-olefin having 3 to 18 carbon atoms. And a copolymer of propylene and ethylene and / or butene-1, ethylene and vinyl acetate, and / or an organic carboxylic acid derivative having an ethylenically unsaturated bond such as acrylic acid ester / methacrylic acid ester. And the like. In particular, it is preferable that the core layer is polyester and the sheath layer is polyethylene from the viewpoint of workability, strength, adhesion and the like.

Next, the method for producing the horticultural sheet of the present invention is as follows, for example. First, the thermoplastic resin and the filler,
If necessary, a dispersant, a stabilizer and the like are mixed or kneaded by a usual method using a roll type or Banbury type kneader or a single-screw or twin-screw extruder to obtain a composition. This composition is then applied to a non-woven fabric of 5 to 150 μm.
Although the laminate laminated in the above range is stretched, the breathability and the reflection characteristics due to microvoids are exhibited, but the stretching is performed uniaxially or biaxially. In the case of uniaxial stretching, roll stretching is usually preferred. In the case of biaxial stretching, simultaneous biaxial stretching may be possible, or sequential biaxial stretching in which transverse stretching is carried out after longitudinal stretching is possible. The appropriate draw ratio varies depending on the resin composition and the type of the non-woven fabric, but a draw ratio of 1.1 to 8.0 is preferable.
If it is less than 1.1 times, breathability and reflection characteristics cannot be expected,
If it exceeds 8.0 times, the material may be broken or the tear strength in the machine direction is lowered, which is not preferable. A more preferable draw ratio is 1.2 to 4.0 times. The stretching temperature varies depending on the resin composition, but is usually preferably in the range of 30 to 140 ° C. When the temperature is lower than 30 ° C, the stability during stretching is not preferable, and when the temperature is higher than 140 ° C, microvoids are less likely to occur, which is not preferable. In particular, it is preferable that the film is stretched in the range of 30 to 140 ° C. and then heat set in the range of 80 ° C. to 170 ° C. in order to prevent wrinkles of the film.

[0017]

The horticultural sheet of the present invention is excellent in water vapor transmission controllability, and exhibits good pest repellent effect and good crop growing effect. It can be used as a covering material for agriculture, for example, for tunnels, house outer coverings, curtains, mulches and the like. In particular, it is extremely effective to use the mulch as a mulch for cultivating fruit trees such as mandarin oranges, persimmons, pears, and grapes.

[0018]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited thereto. The water pressure resistance, which is a measure of the moisture permeability, the reflection property, the pest repellent effect, and the water drop impermeability shown in Examples and Comparative Examples, was determined according to the following criteria.

Water vapor transmission rate: 40 according to JIS Z0208
The water vapor permeation rate was measured under the conditions of ° C and 90% RH.

Reflection property: The reflectance (%) at wavelengths 0.4, 0.6, and 0.8 μm was shown.

Pest repellent effect: The number of aphids (in 40 leaves of green bean) during 30 days of mulching cultivation was measured.

Water pressure resistance: According to JIS L1092-A method, the water level when water came out from three places on the back side of the test piece was measured.

Example 1 Linear low density polyethylene A (manufactured by Sumitomo Chemical Co., Ltd.,
Excellen VL200, density 0.900 g / cm ³ )
20 parts by weight, linear low-density polyethylene B (Sumitomo Chemical Co., Ltd., Sumikasen-L GA801, density 0.9
20 g / cm ³ ) 60 parts by weight, high-pressure low-density polyethylene (Sumitomo Chemical Co., Ltd., Sumikasen F208-
0, density 0.922 g / cm ³ ) 100 parts by weight of thermoplastic resin consisting of 20 parts by weight, 135 parts by weight of calcium carbonate (White SSB (red) manufactured by Shiraishi Calcium Co., Ltd.), potassium whisker titanate (Otsuka Chemical) Manufactured by Tismo D) and kneaded with a composition of Banbury type kneader.
27) to a nonwoven fabric (Unitika, Elves SO303WDO) with a thickness of 100 μm and a basis weight of 30 g / m ² made of concentric fibers whose sheath layer is polyethylene (melting point: 124 ° C.).
Lamination was carried out at a resin temperature of 0 ° C. and a basis weight of 30 g / m ² . This laminated sheet was uniaxially stretched 1.3 times at 50 ° C. in a uniaxial direction to obtain a horticultural sheet. As shown in Table 2, the obtained horticultural sheet exhibited a remarkable pest repellent effect due to high water vapor transmission rate, water pressure resistance and good reflection characteristics.

Example 2 A sheet was obtained in the same manner as in Example 1, except that the potassium whisker titanate of Example 1 was changed to titanium oxide (anatase type) powder. As shown in Table 2, the obtained sheet had high water vapor transmission rate, water pressure resistance and good reflection characteristics.

Example 3 Linear low density polyethylene A (manufactured by Sumitomo Chemical Co., Ltd.,
Excellen VL200, Density 0.900g / cm³)
20 parts by weight, linear low-density polyethylene C (Sumitomo Chemical Industries, Ltd.
Co., Ltd., Sumikasen-α CS3003, density 0.
932 g / cm ³) 60 parts by weight, high pressure method low density polyethylene
Ren (Sumikasen F208 manufactured by Sumitomo Chemical Co., Ltd.
-0, density 0.922g / cm³) 20 parts by weight
100 parts by weight of thermoplastic resin and calcium carbonate (Shiraishi
Lucon Co., Ltd., Whiten SSB (red) 135
Parts by weight, potassium whisker titanate (Otsuka Chemical, Tis
And a composition containing 15 parts by weight of D) in a Banbury type mixture.
After kneading with a kneader, the core layer is made of polyester (melting point 257
℃), the concentric sheath layer is polyethylene (melting point 124 ℃)
Thickness of 100μm, basis weight 30g / m²No
27 on woven fabric (Unitika, Elves SO303WDO)
30 g / m at 0 ° C resin temperature²Laminated by basis weight
did. This laminated sheet is uniaxial with a roll type stretching machine.
By stretching 1.3 times in the direction at 50 ° C for gardening
Got The obtained horticultural sheet is as shown in Table 2.
It showed good moisture permeability, water pressure resistance and reflection characteristics.

Example 4 The same composition as used in Example 3 was used, and this was used as a polyester non-woven fabric (Smash, manufactured by Asahi Kasei Co., Ltd.).
Thickness of 190 μm) at a resin temperature of 300 ° C. of 80 g / m
Laminated at a basis weight of ² . A horticultural sheet was obtained by uniaxially stretching this laminated sheet 3.5 times at 50 ° C. in a uniaxial direction. As shown in Table 2, the obtained sheet exhibited a remarkable pest repellent effect due to high moisture permeability, water resistance, and good reflection characteristics.

Comparative Example 1 Linear low density polyethylene A (manufactured by Sumitomo Chemical Co., Ltd.,
Excellen VL200, density 0.900 g / cm ³ )
20 parts by weight, linear low density polyethylene C (Sumitomo Chemical Co., Ltd., Sumikasen-α CS3003, density 0.
932 g / cm ³ ) 60 parts by weight, high-pressure low-density polyethylene (Sumitomo Chemical Co., Ltd., Sumikasen F208)
-0, 100 parts by weight of a thermoplastic resin consisting of 20 parts by weight of a density of 0.922 g / cm ³ ) and calcium carbonate (White SSB (red) manufactured by Shiraishi Calcium Co., Ltd.) 135
After kneading a composition consisting of 15 parts by weight of potassium whisker titanate (manufactured by Otsuka Chemical Co., Ltd., Tismo D) with a Banbury type kneader, a T-die processing method was performed at a resin temperature of 270 ° C. to a thickness of 20 μm. Got the sheet. This sheet was stretched 1.8 times in a uniaxial direction with a roll type stretching machine to obtain a sheet, but the water pressure resistance was extremely deteriorated, and the sheet had poor mechanical properties.

Comparative Example 2 Except that the lamination of the resin composition and the non-woven fabric at the time of processing was carried out using a urethane-based adhesive (film thickness 60 μm), and the draw ratio was 1.8 times. The sheet was processed in the same manner as in Example 3 to obtain a sheet. The moisture permeability was extremely deteriorated, and the sheet lacked water vapor permeability.

Comparative Example 3 A sheet was obtained by the same process as in Example 1 except that the stretching process was not performed, but the obtained sheet had extremely poor moisture permeability.

Comparative Example 4 An attempt was made to carry out processing in the same manner as in Example 1 except that the draw ratio was 8.5 times, but the sheet could not be obtained because it broke in the middle.

Comparative Example 5 Linear low density polyethylene A (manufactured by Sumitomo Chemical Co., Ltd.,
Excellen VL200, density 0.900 g / cm ³ )
20 parts by weight, linear low density polyethylene C (Sumitomo Chemical Co., Ltd., Sumikasen-α CS3003, density 0.
932 g / cm ³ ) 60 parts by weight, high-pressure low-density polyethylene (Sumitomo Chemical Co., Ltd., Sumikasen F208)
After kneading a thermoplastic resin composition consisting of −0 and a density of 0.922 g / cm ³ ) by 20 parts by weight with a Banbury type kneader, a sheet having a thickness of 100 μm was formed at a resin temperature of 270 ° C. by a T-die processing method. Obtained. This sheet was stretched 1.3 times in a uniaxial direction with a roll type stretching machine to obtain a sheet. The obtained sheet had poor moisture permeability as compared with Example 3,
The reflection property also did not have a pest repellent effect.

[0032]

[Table 1]

[0033]

[Table 2]

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[Procedure amendment]

[Submission date] May 21, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

Examples of the filler include carbonates such as calcium carbonate, magnesium carbonate and barium carbonate, sulfates such as barium sulfate, magnesium sulfate and calcium sulfate,
Phosphates such as magnesium phosphate and calcium phosphate, hydroxides such as magnesium hydroxide and aluminum hydroxide, alumina, silica, oxides such as magnesium oxide, calcium oxide, zinc oxide and titanium oxide, aluminum powder, zeolite, and shirasu Inorganic fillers such as white clay, diatomaceous earth, talc and volcanic ash, and cellulosic powders such as wood powder and pulp powder, nylon powder, polycarbonate powder, polypropylene powder, poly-4-methylpentene-
There may be mentioned synthetic resin powders such as 1 powder and organic fillers such as starch, which may be used alone or in combination. The average particle size of the filler is 0.1 to 20 μm.
m is preferable from the viewpoint of film uniformity due to dispersion of the filler, and particularly preferably 0.8 to 10 μm from the viewpoint of processability. The reflectance at 0.4 to 0.8 μm is 4
Filler within a range showing a reflection spectrum of 0% or more
It is also possible to use a coloring agent such as a pigment.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction content]

Examples of the resin component constituting a part or the whole of the nonwoven fabric include polyester, nylon, α-olefin homopolymers such as polyethylene, polypropylene and polybutene, and ethylene and at least one α-olefin having 3 to 18 carbon atoms. And a copolymer of propylene and ethylene and / or butene-1, ethylene and vinyl acetate, and / or an organic carboxylic acid derivative having an ethylenically unsaturated bond such as acrylic acid ester / methacrylic acid ester. And the like. In particular, it is preferable that the core layer is polyester and the sheath layer is polyethylene from the viewpoint of workability, strength, adhesion and the like. Also, use a non-woven fabric that is highly absorbent.
You can Furthermore, if necessary, color it with a pigment, etc.
It is also possible to use a non-woven fabric .

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Claims (1)

[Claims] 1. A thermoplastic resin 100 parts by weight and a filler 50 to 50 parts by weight.
A sheet obtained by laminating a resin composition consisting of 400 parts by weight on a non-woven fabric and then stretching it uniaxially or biaxially at a ratio of 1.1 to 8.0 times has a reflection peak at a wavelength of less than 0.4 μm, A horticultural sheet having a reflection spectrum showing a reflectance of 40% or more at a wavelength of 0.4 to 0.8 μm.