JP2002266248A - Thermoplastic resin sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic resin sheet suitable for a weedkilling sheet, capable of being well drained scarcely generating water pockets and having no problems from a hygienic viewpoint and a viewpoint of safety in agricultural work, while keeping a weedkilling function which conventional sheets have. SOLUTION: This thermoplastic resin sheet is woven by using tape yarn made of a thermoplastic resin and having a fineness of 300-2,000 dtex as the warp and the weft, wherein at least one of both the surfaces of the tape yarn used as the warp and/or the weft has a surfactant layer on it, and the sheet has a open area ratio of <=0.1%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a thermoplastic resin sheet obtained by weaving a tape yarn. More specifically, the present invention relates to a thermoplastic resin sheet having a weedproof function and good drainage because of having water permeability, and suitable as a weedproof sheet.

[0002]

2. Description of the Related Art In the field of agriculture, particularly in the field of horticulture, weed removal is an important operation and has conventionally been performed manually. In order to reduce the burden of this weeding work, herbicides have come to be used. A method of spreading synthetic resin sheets is widely used. This synthetic resin sheet is called a grass sheet,
Since there is no water permeability, when laid in a field scene with many irregularities, water pools are formed due to rainfall or irrigation, and there is a problem in hygiene. In addition, the conventional synthetic resin sheet has a problem in terms of safety in agricultural work because it has a smooth surface and is liable to slip even when slightly wet with water, and the perforated sheet has a drawback that water is good but tears easily spread from the holes.

[0003]

DISCLOSURE OF THE INVENTION The present invention relates to a herbicidal sheet having the weed-proofing function of a conventional weed-proofing sheet, having good drainage and hardly forming water pools, and having no problems in hygiene and agricultural work safety. It is an object to provide a thermoplastic resin sheet suitable as a sheet.

[0004]

As a result of intensive studies, the present inventor has found that a tape yarn made of a thermoplastic resin is used as a warp and a weft, and at least one surface of the tape yarn serving as at least one of the yarns has a surface active property. Apply the agent,
It has been found that the above problem can be solved by a thermoplastic resin sheet having water permeability obtained by densely weaving these tape yarns, and the present invention has been completed based on the findings.

The present invention comprises the following. (1) Fineness of thermoplastic resin 300 to 2000 dt
ex, a thermoplastic resin sheet obtained by weaving the warp yarn and the weft yarn, wherein the tape yarn used as the warp yarn and / or the weft yarn has a surfactant layer on at least one surface thereof. The porosity is 0.1
% Of a thermoplastic resin sheet.

(2) The thermoplastic resin sheet according to the above (1), wherein the thermoplastic resin is at least one selected from an ethylene resin and a propylene resin.

(3) The thermoplastic resin sheet according to the above (1) or (2), wherein the surfactant layer is formed by applying a surfactant.

(4) The surfactants are polyoxyethylene alkyl (C12 to C18) ethers, polyhydric alcohol fatty acid (C12 to C18) esters, polyoxyethylene polyhydric alcohol fatty acids (C12 to C18) 18) The thermoplastic resin sheet according to any one of the above items (1) to (3), which is one kind or two or more kinds selected from the group of esters.

[0009]

Embodiments of the present invention will be described below.

In the thermoplastic resin sheet of the present invention, the fineness of the tape yarn for warp and weft is 300 to 2000.
dtex. Above all, the fineness of the warp tape yarn is 300 to 800 dtex, preferably 400 to 700 dtex.
dtex, fineness of tape yarn for weft is 700-20
00 dtex, preferably 900 to 1200 dtex. In addition, the width of the tape yarn for the warp and the weft is preferably 0.5 to 10 mm.
The slit width of the warp tape yarn is 0.5 to 3 mm,
The slit width of the tape yarn for the weft is desirably 2 to 8 mm. When the fineness and width of the tape yarn are in the above ranges, the obtained thermoplastic resin sheet has sufficient strength, is flexible, and is easy to handle.

In the thermoplastic resin sheet of the present invention, the tensile strength and elongation (JI) of the tape yarns for warp and weft are determined.
SL 1013 "Test method for chemical fiber filament yarn") preferably has a tensile strength of not less than 2.5 cN / dtex and an elongation of not more than 45%, preferably not more than 25%. A good thermoplastic resin sheet is obtained.

In the present invention, the thermoplastic resin constituting the tape yarn is, for example, ethylene resin, propylene resin, vinyl chloride resin, styrene resin, amide resin, polyethylene terephthalate, acrylonitrile butadiene styrene resin. And ethylene / vinyl acetate copolymer. Among them, olefin resins that are relatively inexpensive and have excellent thermal and mechanical properties and recyclability and do not generate harmful gases during combustion are preferable, and ethylene resins and propylene resins are particularly preferable because of their light weight.

The propylene resin tape yarn is used for both warp and weft. Ethylene-based resin tape yarns are mainly used as weft yarns in order to impart flexibility to a thermoplastic resin sheet. As warp yarns, propylene-based resin tape yarns having excellent strength are suitable.

In the present invention, the ethylene resin includes a homopolymer of ethylene, a binary or more random or block copolymer of ethylene with a monomer other than ethylene, and two or more of these. And mixtures thereof. In the present invention, the main component refers to a component that is the most common. The monomer other than ethylene is not particularly limited, but propylene, 1-butene, 1-pentene,
Α- having 3 to 12 carbon atoms, such as 1-hexene and 1-octene;
Examples include olefins, vinyl esters such as vinyl acetate, acrylates such as ethyl acrylate, methacrylates such as methyl methacrylate, and carbon monoxide. These may be used alone or in combination of two or more.

The melt flow rate of the ethylene-based resin (JIS K 7210-1976 “Method for testing flow of thermoplastics” (condition 4, test temperature 190 in Table 1)
C., measured by a test load of 21.18 N), hereinafter referred to as MFR), is not particularly limited, but if it is 0.1 to 5 g / 10 min, the extrudability is good and the strength of the obtained tape yarn is also sufficient, which is preferable. . The shrinkage at 100 ° C. of the tape yarn for warp and weft obtained from the ethylene-based resin (JIS L 1013 “Test method for chemical fiber filament yarn” dry heat shrinkage B method) is desirably 4% or less. Thereby, a thermoplastic resin sheet without heat shrinkage can be obtained.

In the present invention, the propylene resin may be a homopolymer of propylene, a binary or more random or block copolymer of propylene with a monomer other than propylene as a main component, and two or more of these. And mixtures thereof. The monomer other than propylene is not particularly limited, but ethylene, 1-butene, 1-
Pentene, 1-hexene, 1-octene, etc.
And 12 α-olefins. These may be used alone or in combination of two or more.

The melt flow rate of the propylene resin (JIS K 7210-1976 “Testing method for thermoplastic plastic flow” (condition 14, test temperature 2 in Table 1)
30 ° C, test load 21.18N), hereinafter MF
R) is not particularly limited, but is 0.1 to 10 g / 10
Min., Preferably 2 to 7 g / 10 min., The extrudability is good and the strength of the obtained tape yarn is sufficient, which is preferable. Further, the shrinkage rate (J) of the tape yarn for warp and weft obtained from the propylene resin at 130 ° C.
It is desirable that IS L 1013 (test method for chemical fiber filament yarn) dry heat shrinkage (B method) is 4% or less, thereby obtaining a thermoplastic resin sheet without heat shrinkage.

In the present invention, the tape yarn may be added to the thermoplastic resin, if necessary, if necessary, with various additives usually used for the thermoplastic resin, for example, an antioxidant, a light stabilizer,
Compounds obtained by compounding ultraviolet absorbers, antistatic agents, neutralizing agents, lubricants, antiblocking agents, flame retardants, antibacterial agents, pigments (inorganic pigments, organic pigments, pearl pigments, etc.), It can be manufactured by forming into a film by extrusion molding or the like, further slitting and stretching this film.

When a high light-shielding property is required for the thermoplastic resin sheet, a pigment having a particularly high hiding power, such as a black pigment, is suitable as the pigment. When a thermoplastic resin sheet obtained using a black pigment is used as a weed prevention sheet, the weed prevention sheet can absorb heat and kill weeds. Further, when a white pigment, a pearl pigment, or the like is used, the coloring of the fruit can be promoted by using the reflected light of the weed prevention sheet.

In the present invention, the above-mentioned compound contains a thermoplastic resin and other additives to be added as required. It can be obtained by dispersing and mixing more uniformly. Thereafter, the mixture is heated and melt-kneaded as required using a mixing roll, an extruder, or the like, and further obtained as pellets cut into granules.

In the present invention, examples of a method of forming the compound into a film include an extrusion molding method such as a T-die method and an inflation method, and a calendering method. An easy extrusion method is preferred. The stretching after slitting the film is uniaxial stretching in the vertical direction (MD). As a method for heating the film during stretching, a method of passing hot air or hot water or a method of contacting with a hot plate or a heating roll is used. Yes, any of them can be used. The stretching ratio is preferably 4 to 12 times.

The thermoplastic resin sheet of the present invention is obtained by densely weaving the above-described tape yarn as a warp and a weft. The number of tape yarns for weaving is 22 for warp when the fineness of the tape yarn is 400 to 700 dtex.
26 to 2.54 cm, and the weft is 13 to 17 yarns in a case where the fineness of the tape yarn is 900 to 1200 dtex.
54 cm can be exemplified, and the basis weight of the thermoplastic resin sheet is 10
0 to 150 g / m ² can be exemplified. The tensile strength and elongation (JIS L 1096 “General woven fabric test method”) of the thermoplastic resin sheet are not particularly limited, but the tensile strength is 900 N / 5 cm or more in the vertical (warp) direction, and the horizontal (weft)
The direction is 750 N / 5 cm or more, and the elongation is less than 25% in the vertical (warp) direction and less than 25% in the horizontal (weft) direction.
It is desirable that the heat shrinkage at 30 ° C. is 3% or less.

Since the thermoplastic resin sheet of the present invention is densely woven by using the tape yarn as the warp and the weft as described above, there is almost no space between the adjacent warps and between the wefts, so that the obtained thermoplastic resin sheet can be used. The porosity of the resin sheet is 0.1% or less, preferably 0.01% or less. In addition, the air permeability (JIS L 1096 “General fabric test method”, method A (Fragile method)) is 1 to 50 cm ³ / cm.
³ · s, preferably 5 to ³⁰ cm ³ / cm ³ · s. The above-mentioned thermoplastic resin sheet has low air permeability, and when the tape yarn is black, the light transmission amount is small. Therefore, the thermoplastic resin sheet is suitable as a grass-proof sheet, but on the other hand, drainage, that is, water permeability is apt to be insufficient, and when laid on an uneven surface, water pools are formed, and hygiene and work safety are ensured. There is a problem.

In the thermoplastic resin sheet of the present invention,
In order to improve poor water permeability, a surfactant layer is formed on at least one surface of a tape yarn used as a warp and / or a weft. To form the surfactant layer,
Examples thereof include a method of adding a surfactant to a formulation for producing a tape yarn and causing the surfactant to bleed out on the surface of the tape yarn, and a method of applying a surfactant to the surface of the tape yarn. In this case, the tape yarn to be kneaded-bleed-out or applied may be either one or both of the tape yarns used as the warp and the weft, but at least one surface of the tape yarn used as the warp has a surface active agent. It is desirable to apply an agent from the viewpoint of economy and weaving workability.

As the surfactant, those used by being applied to a thermoplastic resin sheet can be used. Cationic surfactants, anionic surfactants, nonionic surfactants,
Examples include amphoteric surfactants and mixtures of two or more of these.

Examples of the cationic surfactant include aliphatic amine salts, quaternary ammonium salts, and alkylpyridinium salts. Examples of the anionic surfactant include fatty acid salts, higher alcohol sulfates, liquid fatty oil sulfates, sulfates of aliphatic amines and aliphatic amides, fatty alcohol phosphates, and sulfonic acids of dibasic fatty acid esters. Examples thereof include salts, fatty acid amide sulfonates, alkylaryl sulfonates, and formalin-condensed naphthalene sulfonates.

Examples of the nonionic surfactant include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenol ethers, polyhydric alcohol fatty acid esters, and polyoxyethylene polyhydric alcohol fatty acid esters. Examples of the amphoteric surfactant include a carboxylic acid derivative and an imidazoline derivative.

Among the above-mentioned surfactants, nonionic surfactants are preferable, and when the thermoplastic resin sheet of the present invention is used for agricultural purposes, polyoxyethylene alkyl (having a carbon number of 12) which has no problem in terms of safety and health. To 18) ethers, polyhydric alcohol fatty acid (C12 to C18) esters and polyoxyethylene polyhydric alcohol fatty acid (C12 to C18) esters are preferably used, and these may be used alone. And two or more kinds can be used in combination. As the polyhydric alcohol, glycerin,
Examples thereof include polyglycerin, sorbitol, sorbitan, pentaerythritol, dipentaerythritol, and polyalkylene glycol.

The amount of the surfactant to be applied is, for example, 0.1 to 5 g / m ² as a solid content.

The method of applying the surfactant to the tape yarn is not particularly limited, but the surfactant aqueous solution may be used in the process of producing a film to be a raw material of the tape yarn, the stretching process of the tape yarn, or the warping process. May be applied by spraying or using an oiling roll.

To manufacture a thermoplastic resin sheet densely by using the tape yarn as a warp and a weft,
Known equipment and methods are used. The woven pattern is not particularly limited, but plain weave is preferable in order to prevent the thermoplastic resin sheet from substantially transmitting sunlight. The end of the thermoplastic resin sheet is preferably subjected to a process such as heat fusion or sewing to prevent the tape yarn from fraying.

In the thermoplastic resin sheet of the present invention,
The color of the tape yarn is not limited, and if it is made black, it can absorb heat and block transmission of light. In addition, for the purpose of improving the workability such as the arrangement of the cultivation containers and the standard of the passage interval, tape yarns having different colors and the like can be woven at regular intervals as warps and / or wefts at regular intervals. In addition, by using a light-reflective tape yarn as the warp and / or the weft, a function of promoting photosynthesis of plants by reflected light can be imparted to the thermoplastic resin sheet.

If the thermoplastic resin sheet of the present invention is perforated and used as a multi-sheet, it can be used repeatedly due to its excellent strength, and the amount of agricultural waste generated can be reduced.

[0034]

The present invention will be described below in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples. The evaluation methods used in the examples and comparative examples are shown below. Opening ratio: In the present invention, the opening ratio is a ratio of a total area of gaps such as meshes to a total area of the thermoplastic resin sheet. The method of measuring the porosity can be determined by an optical microscope (usually 100
The size of the opening portion through which light passes directly from the direction perpendicular to the surface of the thermoplastic resin sheet is measured using a microscope scale, and the opening formed by the tape yarn per unit area (A). The total area (B) is measured and calculated by the following equation. Porosity (%) = B ÷ A × 100

Water permeability: 120 m inner diameter with flange
m, using two 20cm long plastic pipes,
The thermoplastic resin sheet sample was sandwiched between the flange surfaces of the two pipes and fixed with bolts. While holding the thermoplastic resin sheet sample horizontally, 50 ml of water was poured from above, and the time for water to permeate the sheet sample (water permeation time) was measured.

Weed control: A test was conducted on a vinyl house for agricultural use in Kumamoto Prefecture, where the weeds were laid between furrows and observed one month later.

Example 1 4.0% by weight of a carbon black masterbatch (concentration: 40% by weight) was added to a polypropylene resin (MFR; 5.3 g / 10 minutes, manufactured by Chisso Corporation) and mixed using a tumbler mixer. A formulation was made. T
After slitting the film formed using a die extruder, the film is stretched 8 times in the vertical direction (MD), annealed, and has a fineness of 560 dtex, a width of 1.2 mm, and a tensile strength of 4.5 cN.
/ Dtex, a warp tape yarn having an elongation of 15% was obtained. Similarly, fineness 1110 dtex, width 3 m
m, a tensile strength of 4.3 cN / dtex and an elongation of 14% were obtained.

In addition, with respect to the warp tape yarn,
An aqueous solution of a surfactant sorbitan monopalmitate ethylene oxide (20 mol) adduct was applied to the surface at a solid content of 0.5 g / m ² by a method using an oiling roll in the stretching step of the tape yarn, followed by drying. Using the surfactant-coated tape yarn for the warp and the tape yarn without coating for the weft, weaving was performed densely to prepare a thermoplastic resin sheet. The woven pattern is plain weave, and the number of tape yarns to be driven is 24 warps / 2.54 cm, and 15 wefts /
It was 2.54 cm.

The basis weight of the obtained thermoplastic resin sheet was 13
0 g / m ² , and the tensile strength is 1000 N /
5 cm, horizontal (weft) direction is 910 N / 5 cm, elongation is 15% in both the vertical (warp) direction and horizontal (weft) direction, the porosity is 0.01%, and the air permeability is 15.4 cm ³ / cm ^3. s. To prevent fraying the edges of the thermoplastic resin sheet,
Heat fused. The obtained thermoplastic resin sheet was subjected to an evaluation test. The water permeability was good and the water transmission time was between 1 and 2 minutes. Even in the test of herbicidal properties, no water pool was formed at the time of irrigation, the farming work was possible without slipping even when walking in the furrow, there was almost no occurrence of weed one month after laying, and there was no breakage of the sheet. .

Comparative Example 1 A thermoplastic resin sheet was obtained in the same manner as in Example 1, except that the surfactant was not applied to the tape yarn used as the warp. The obtained thermoplastic resin sheet was subjected to an evaluation test. The water permeability was poor and the water permeation time was 20 minutes or more. In the herbicidal test, water pools were formed during irrigation and slippery, which was a safety problem. However, weeds were hardly generated one month after laying, and the sheets were not broken.

Comparative Example 2 In place of the thermoplastic resin sheet of Example 1, a commercially available polyethylene black multi-film (thickness: 0.05 mm) was laid between ridges and subjected to an evaluation test. In the herbicidal test, since there was no water permeability, a water pool was formed and slippery, which was a safety problem. One month after laying, weeds emerged from the breaks caused by repeated walking.

[0042]

The thermoplastic resin sheet of the present invention has a surfactant layer while having the weed control function of a conventional weed control sheet, so that it has good drainage and is difficult to collect water.
When a polyoxyethylene polyhydric alcohol fatty acid ester or the like is used as a surfactant, it is suitable as a herbicidal sheet without problems in hygiene and safety in agricultural work. In particular, when the thermoplastic resin is an ethylene-based resin or a propylene-based resin, the thermoplastic resin sheet is lightweight, hardly torn, and suitable as a paddy field ridge sheet or a gardening material.

Claims (4)

[Claims] 1. A fineness of 300 to 200 made of a thermoplastic resin.
A thermoplastic resin sheet obtained by weaving using 0 dtex tape yarn for warp and weft, wherein the tape yarn used as warp and / or weft has a surfactant layer on at least one surface thereof, and A thermoplastic resin sheet having a porosity of 0.1% or less. 2. The thermoplastic resin sheet according to claim 1, wherein the thermoplastic resin is at least one selected from an ethylene resin and a propylene resin. 3. The thermoplastic resin sheet according to claim 1, wherein the surfactant layer is formed by applying a surfactant. 4. A surfactant comprising a polyoxyethylene alkyl (C12 to C18) ether, a polyhydric alcohol fatty acid (C12 to C18) ester, a polyoxyethylene polyhydric alcohol fatty acid (C12 to C18) ) One or more selected from the group of esters.
The thermoplastic resin sheet according to any one of claims 1 to 3.