JP3069670B2 - Gardening sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a horticultural sheet.
More specifically, the present invention relates to a horticultural sheet having a water vapor transmission control property, which is excellent in a pest repellent effect, a crop growing effect, and a strength.

[0002]

2. Description of the Related Art Conventionally, as a mulching film for repelling pests, there is a mulching film in which the reflection characteristics are improved by a layer containing an inorganic compound in a resin as described in JP-A-62-265927. In addition, water vapor permeability cannot be controlled, and depending on the environment, the amount of water in the soil varies greatly, which may adversely affect crop growth.
The publication also proposes to provide a through hole having a hole diameter of 0.3 to 10 mmφ. However, since the hole diameter is large, not only water vapor but also water is transmitted, and the amount of water in the soil is controlled. It was not effective in a sense.

[0003]

Means for Solving the Problems The present inventors control the amount of water in the soil by impermeable water and permeate water vapor, and have the effect of repelling pests and the effect of growing crops by reflected light, and high strength. I have been studying how to get a sheet with it. As a result, it has been found that the above-mentioned problems can be solved by disposing a layer obtained by stretching a resin composition comprising a resin and a specific filler, and further disposing a nonwoven fabric on the layer, and have completed 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.
A sheet obtained by stretching at a magnification of 8.0 times has a reflection peak at a wavelength of less than 0.4 μm, and a wavelength of 0.4 to
A horticultural sheet characterized by having a reflection spectrum whose reflectance at 0.8 μm is 40% or more.

The thermoplastic resin used in the present invention includes, for example, α-olefin homopolymers such as low-density polyethylene, high-density polyethylene, polypropylene and polybutene, and ethylene and at least one α-olefin having 3 to 18 carbon atoms.
Organic carboxylic acid derivatives having an ethylenically unsaturated bond such as copolymers with olefins, copolymers with propylene and ethylene and / or butene-1, ethylene and vinyl acetate and / or acrylates and methacrylates And the like. 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 blending a filler,
Furthermore, low density polyethylene, ethylene and C3-8
Is preferred from the viewpoint of processability and stretchability of the film.

In the present invention, when the amount of the filler is less than 50 parts by weight based on 100 parts by weight of the thermoplastic resin, it is difficult to exhibit the water vapor permeation controllability. Is not preferable because it deteriorates. Particularly, from the viewpoint of processing stability, the amount of the filler is 70 to 20.
0 parts by weight is preferred.

[0007] 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 preferred.

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, oxides such as alumina, silica, magnesium oxide, calcium oxide, zinc oxide and titanium oxide, aluminum powder, zeolite and shirasu Inorganic fillers such as clay, diatomaceous earth, talc and volcanic ash, cellulosic powders such as wood powder and pulp powder, nylon powder, polycarbonate powder, polypropylene powder, poly-4-methylpentene
Organic powders such as synthetic resin-based powders such as No. 1 powder and starch, and these can be used alone or in combination. The filler has an average particle size of 0.1 to 20 μm.
m is preferable from the viewpoint of uniformity of the film due to dispersion of the filler, and particularly preferably 0.8 to 10 μm from the viewpoint of processability.

[0009] In the horticultural sheet of the present invention, the wavelength of 0.1.
The reason for having a reflection peak at less than 4 μm was that various studies were carried out for the purpose of repelling effects against crop pests such as aphids and Thrips palmi as a result of a wavelength of 0.4.
This is because a film showing a spectrum having a reflection peak at less than μm is effective in controlling pests. In particular, the wavelength 0.4
A ratio RA / RB of 1.4 or more between the UV reflectance RA of less than μm and the visible light reflectance RB at a wavelength of 0.5 μm is remarkably effective for repelling pests.

[0010] Further, having a reflection spectrum showing a reflectance of 40% or more at a wavelength of 0.4 to 0.8 µm,
This is because a crop growing effect by reflected light is exhibited. In particular, in order to exhibit a pest repellent effect and a crop growing effect, 1 to 30% by weight of the filler is a titanate compound and / or
Alternatively, it is preferably a zirconium compound.

The horticultural sheet of the present invention is obtained by laminating a resin composition exhibiting water vapor permeation controllability and reflection characteristics on one or both sides of a breathable nonwoven fabric, and then stretching the same uniaxially or biaxially with the nonwoven fabric. Obtainable. Films without a nonwoven fabric are not preferred because the strength is reduced, and when bonding with a nonwoven fabric is performed partially or entirely with heat or an adhesive resin, the film and the nonwoven fabric do not peel or exhibit no moisture permeability. Is not preferred.

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

In the method of the present invention, in which the resin composition and the nonwoven fabric are stretched simultaneously with the nonwoven fabric after being melt-laminated on the nonwoven fabric, if the adhesive strength between the resin composition and the nonwoven fabric is not high, the resin composition is peeled off during stretching. A resin composition containing at least one low-melting resin component having a melting point lower by at least 50 ° C. than the melt lamination temperature of the resin composition is used. As such a nonwoven fabric, for example, a nonwoven fabric composed of a single resin component, the low-melting-point resin component adhered by solution immersion, or a mixture obtained by mixing two or more resin components into fibers, fibers, Nonwoven fabrics formed by mixing two or more resin components are exemplified. Examples of a fiber obtained by mixing fibers with two or more resin components include a concentric multilayer type including a core layer and a sheath layer, and a multilayer type in which each resin is eccentric and a part or all of the sheath layer is formed of the low melting point resin. And at least a part of the fiber is the low-melting-point resin, which is continuously or intermittently appeared on the fiber surface. In particular, from the viewpoint of the strength of the nonwoven fabric, a nonwoven fabric made of a fiber having a core layer and a sheath layer, and at least the outermost sheath layer made of a low-melting resin component is preferable.

If the difference between the melt lamination temperature and the melting point of the resin component constituting a part or the whole of the nonwoven fabric is less than 50 ° C., it is not preferable because the adhesive strength is not high during the melt lamination, and the melting point of the resin component is less than 40 ° C. In some cases, especially during summer film processing, the tackiness of the film greatly increases,
It is not preferable because the roll separation becomes worse and causes trouble.

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

Next, the method for producing the horticultural sheet of the present invention is, for example, as follows. First, thermoplastic resin and filler,
If necessary, a composition is obtained by mixing or kneading a dispersant, a stabilizer, and the like by an ordinary method using a roll-type or Banbury-type kneader, a single-screw or twin-screw extruder, or the like. The composition is then placed on a nonwoven fabric in a
By stretching the laminated product in the range described above, air permeability and reflection characteristics due to microvoids are developed, 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 is also possible, or sequential biaxial stretching in which stretching in the longitudinal direction is performed and then stretching in the transverse direction is also possible. An appropriate stretching ratio varies depending on the resin composition and the type of nonwoven fabric, but a stretching ratio of 1.1 to 8.0 is preferable.
If it is less than 1.1 times, the air permeability and the reflection characteristics cannot be expected,
If it exceeds 8.0 times, it is not preferable because the material is broken or the tear strength in the longitudinal direction is reduced. A more preferred stretching 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. If the temperature is lower than 30 ° C., the stability at the time of stretching is not preferable. In particular, it is preferable to perform heat setting in the range of 80 to 170 ° C. after stretching in the range of 30 to 140 ° C. in order to prevent wrinkling of the film.

[0017]

Industrial Applicability The horticultural sheet of the present invention is excellent in water vapor transmission controllability, and has a good pest repellent effect and a good crop growing effect. As an agricultural covering material, it can be used, for example, for tunnels, house linings, curtains, mulches, and the like. In particular, it is very effective to use it as a mulch for cultivating fruit trees such as tangerines, persimmons, pears, and grapes.

[0018]

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

Water vapor permeability: JIS Z0208 compliant, 40
The permeation rate of water vapor was measured under the conditions of 90 ° C. and 90% RH.

Reflection characteristics: Reflectance (%) at wavelengths of 0.4, 0.6 and 0.8 μm.

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

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

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, 100 parts by weight of a thermoplastic resin consisting of 20 parts by weight of a density of 0.922 g / cm ³ ), 135 parts by weight of calcium carbonate (Whiten SSB (red), manufactured by Shiraishi Calcium Co., Ltd.), and potassium whisker titanate (Otsuka Chemical) And Tismo D) were kneaded with a Banbury-type kneader, and the core layer was made of polyester (melting point: 257).
C), a sheath layer made of concentric fibers of polyethylene (melting point 124 ° C.) and a thickness of 100 μm, a non-woven fabric having a basis weight of 30 g / m ² (made by Unitika, Elves SO303WDO).
Lamination was performed at a resin temperature of 0 ° C. with a basis weight of 30 g / m ² . The horticultural sheet was obtained by stretching this laminated sheet in a uniaxial direction 1.3 times at 50 ° C. with a roll-type stretching machine. As shown in Table 2, the obtained horticultural sheet exhibited a remarkable pest repellent effect due to high moisture permeability, water pressure resistance and good reflection characteristics.

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

Example 3 Linear low density polyethylene A (manufactured by Sumitomo Chemical Co., Ltd.)
Exelen VL200, density 0.900g / cm^Three)
20 parts by weight, linear low density polyethylene C (Sumitomo Chemical Industries
Sumikasen-α CS3003, density 0.
932g / cm ^Three) 60 parts by weight, high-pressure low-density polyethylene
Ren (Sumikasen F208, manufactured by Sumitomo Chemical Co., Ltd.)
−0, density 0.922 g / cm^Three) 20 parts by weight
100 parts by weight of thermoplastic resin and calcium carbonate (Shiraishi
Lucium Co., Whiteton SSB (red)) 135
Parts by weight, potassium whisker titanate (Otsuka Chemical, Tis
(D) a composition comprising 15 parts by weight of a Banbury-type mixture
After kneading with a kneader, the core layer is made of polyester (melting point: 257).
C), the sheath layer is polyethylene (melting point 124 C)
Thickness of 100 μm, basis weight 30 g / m^TwoNo
27 for woven cloth (made by Unitika, Elves SO303WDO)
At a resin temperature of 0 ° C., 30 g / m^TwoLaminated with basis weight of
did. This laminate sheet is uniaxially rolled with a roll-type stretching machine.
Horticultural sheet by stretching 1.3 times at 50 ° C in the direction
I got it. 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 nonwoven fabric (manufactured by Asahi Kasei Corporation, Smash,
80 g / m at 300 ° C resin temperature
Laminated at a basis weight of ² . The horticultural sheet was obtained by stretching this laminate sheet 3.5 times uniaxially at 50 ° C. with a roll-type stretching machine. 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, density of 0.922 g / cm ³ ) 100 parts by weight of a thermoplastic resin consisting of 20 parts by weight, and calcium carbonate (Whiten SSB (red), manufactured by Shiraishi Calcium Co., Ltd.) 135
After kneading a composition comprising 15 parts by weight of potassium whisker (Tismo D, manufactured by Otsuka Chemical Co., Ltd.) with a Banbury-type kneader, a 20 μm-thick resin was obtained at a resin temperature of 270 ° C. by a T-die processing method. I got a sheet. This sheet was stretched in a uniaxial direction by a factor of 1.8 using a roll-type stretching machine to obtain a sheet. However, the sheet had extremely poor water pressure resistance and poor mechanical properties.

COMPARATIVE EXAMPLE 2 Except for laminating the resin composition and the nonwoven fabric without lamination during processing, using a urethane-based adhesive (thickness: 60 μm) and setting the stretching ratio to 1.8 times, Processing was performed in the same manner as in Example 3 to obtain a sheet. The water vapor permeability was extremely deteriorated, resulting in a sheet lacking in water vapor permeability.

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

Comparative Example 4 Processing was carried out in the same manner as in Example 1 except that the stretching ratio was 8.5, but the sheet was broken in the middle and a sheet could not be obtained.

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)
−0, density 0.922 g / cm ³ ) After kneading the thermoplastic resin composition consisting of 20 parts by weight with a Banbury-type kneader, a sheet having a thickness of 100 μm is formed at a resin temperature of 270 ° C. by a T-die processing method. Obtained. The sheet was stretched 1.3 times in a uniaxial direction by a roll-type stretching machine to obtain a sheet. The obtained sheet had poor moisture permeability as compared with Example 3,
The reflection properties also did not have a pest repellent effect.

[0032]

[Table 1]

[0033]

[Table 2]

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI // B29K 9:00 (56) References JP-A-60-2360 (JP, A) JP-A-62-122545 (JP, A (58) Fields surveyed (Int. Cl. ⁷ , DB name) A01G 13/00 A01M 29/00 A01G 13/02 A01G 9/14

Claims (1)

(57) [Claims] 1. 100 parts by weight of a thermoplastic resin and 50 to 50% by weight of a filler.
A sheet obtained by laminating a resin composition consisting of 400 parts by weight on a nonwoven fabric and then stretching uniaxially or biaxially at a magnification 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 having a reflectance of 40% or more at a wavelength of 0.4 to 0.8 µm.