JPH03130019A - Nonwoven sheet for plant growth - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a nonwoven fabric sheet for growing plants that is placed under a seedling pot.

Conventional technology Conventionally, for example, when cultivating strawberries or flowering trees, seedlings are grown in seedling pots, and once they have grown to a certain extent, they are shipped or transferred. However, because seedling pots are usually used in the form of a forest, weeds can grow in the gaps between the seedling pots and grow, interfering with the growth of the seedlings.

In addition, the roots of the seedlings that protrude from the drainage opening at the bottom of the pot may take root in the field or cultivated land, and become contaminated with soil diseases of the field or cultivated land, or the roots may be cut off during transplantation, resulting in the tree's vigor being significantly reduced. It may decline.

Problems to be Solved by the Invention In order to solve the above-mentioned problems, the present invention spreads a sheet under the seedling pot to prevent weeds from growing between the boas, and also prevents diseases from spreading from the soil to the seedlings. This is intended to prevent the roots from being cut during transplanting, but with a simple sheet, water may accumulate on the resheet during irrigation, causing root rot, or weeds may grow under the sheet, causing the sheet to swell, making it difficult to raise seedlings. The pot may tilt.

When laying a sheet, consideration must be given to its water permeability and inhibition of weed growth.

Means for Solving the Problems The present invention has been made in view of the above points, and uses a nonwoven fabric sheet as the sheet, and at least one side of the sheet is black for light shielding.

That is, the present invention is characterized in that a nonwoven fabric sheet with at least one side black is placed under the seedling growing pot.

Function The nonwoven fabric sheet blocks light and prevents weeds from growing. Furthermore, since the nonwoven fabric sheet has water permeability, water seeps into the soil through the sheet during irrigation.

As mentioned above, the nonwoven fabric sheet used in the present invention is black on at least one side and has light blocking properties, with a light blocking rate of 70% or more, but in order to make it black, one or both sides of the sheet are coated with dye, for example. Alternatively, it may be printed and colored, or the fiber itself may be made black.

It is desirable that the nonwoven fabric sheet has excellent breathability as well as water permeability, and is impermeable to the roots of the seedlings.

In addition, from a manufacturing standpoint, it is desirable that the material be easy to form into paper and heat set easily. These include nonwoven fabrics made by mixing P P -P E* synthetic fibers made of polypropylene and polyethylene with polyolefin staple fibers, and containing polyolefin staple fibers at 10 to 80 Iifi% of the total weight; Examples include nonwoven fabrics containing 10 to 50% by weight of vegetable natural fibers based on the total weight. The latter nonwoven fabric mixed with natural fibers has the advantage of further suppressing slippage and being easy to cut.

The above-mentioned PP-PE composite fiber is a composite of a component consisting essentially of crystalline polypropylene (hereinafter referred to as PP component) and a component consisting of polyethylene (hereinafter referred to as PE component), and its shape is, for example, In the core of the PP component, P
Examples include a core-sheath structure having a sheath of the E component, a two-layer structure in which a PP component and a PE component are laminated together, and a three-layer structure in which a PP component is sandwiched between PE components. Furthermore, in either structure, each layer does not need to be continuous.

The crystalline polypropylene constituting the PP-PE composite fiber is a homopolymer of propylene or propylene and 10 mol% or less, preferably 5 mol% or less of other α-olefins, such as ethylene, 1-butene, ]-hexene, 1-
It is a copolymer with one or more α-olefins such as octene and 1-decene. Such crystalline polypropylene typically has a MFR(L) (ASTM D1238, L
) is 0.1 to 50g/10 mjn, preferably 0
．． 5-30g/10win, melting point (ASTM D3
418) is 135°C or higher, preferably 145°C or higher.

On the other hand, the polyethylene that makes up the PP-PE composite component is
Ethylene homopolymer or ethylene and 20 mol%
Hereinafter, preferably 15 mol% or less of other α-olefins, such as propylene, 1-butene, 1-hexene, 1
It is a copolymer with one or more α-olefins such as -octene, 1-decene, and 4-methyl-l-pentene. Such polyethylene typically has a MFR(E) (
ASTM D1238, E) 0.1-100g/1
0 m1n, preferably 0.5 to 60 g/10 m1n,
The melting point is 90°C or higher, preferably 100°C or higher.

For the specific structure and manufacturing method of PP-PE composite fiber, see, for example, Japanese Patent Publication No. 52-37097, Japanese Patent Publication No. 55
17807 and Japanese Patent Publication No. 55483, but other PPP composite fibers can also be suitably used.

Generally speaking, these PP-PE composite fibers have good thermal adhesion, low thermal shrinkage, good dimensional stability, bulkiness, and porosity.

Regarding polyolefin short fibers to be mixed with PP-PE composite fibers, examples include polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-1-butene copolymer, ethylene-4-methyl-1-pentene copolymer, etc. A polyolefin resin consisting of one or more α-olefins, especially a homopolymer of ethylene, or ethylene and 20 mol% or less, preferably 15 mol% or less of other α-olefins, such as propylene, 1-
Butene, l-hexene, 1-octene, l-decene, 4
- One or more types of α such as methyl-1-pentene
- Short fibers obtained by melt-spinning polyethylene, which is a copolymer mainly composed of ethylene with olefin, and then cuffing, and splint yarns obtained by opening polyethylene films. Examples include a pulp-like material obtained by a flash spinning method (hereinafter referred to as a synthetic valve).

Among these, the synthetic bulb shape is superior in terms of uniform mixing properties with the PP-PE composite fiber.

Regarding the manufacturing method of synthetic valves, for example, Japanese Patent Publication No. 52-470
As described in Japanese Patent Application No. 49, polyvinyl alcohol is used during manufacture as a synthetic valve, and a synthetic valve having polyvinyl alcohol adhered to its surface is preferably used here.

The use of polyvinyl alcohol during the production of synthetic valves not only improves the spinnability in the flash spinning method, but also imparts hydrophilicity to the resulting fibers.

In order to further improve hydrophilicity, it is important to treat the short polyolefin fibers with a nonionic surfactant. When using the flash spinning method, the treatment with a surfactant is preferably carried out by adding a surfactant to the water slurry since the bulb-shaped short fibers become a water slurry during the manufacturing stage. That is, the treatment with a surfactant is performed by making the short polyolefin fibers into a slurry mixture of water containing the nonionic surfactant and then dewatering the mixture.

The nonionic surfactant used at this time is (a) HLB
is within the range of 2 to 20, and (b) melting point (JIS
K 0064) is required to be higher than the temperature at which the slurry mixture is dehydrated.

If the HLB is outside this range, sufficient hydrophilicity cannot be imparted, and if the melting point is lower than the temperature at which the slurry mixture is dehydrated, it will be in a liquid state in the water slurry, so it will not adhere well to the thermoplastic short fibers. Deteriorate. Since the temperature during dehydration of the water slurry is usually about 10 to 50°C, a surfactant having a melting point in the range of about 20 to 80°C is used.

Nonionic surfactants that meet the above conditions include, for example, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether (polyoxyethylene nonylphenyl ether, etc.), polyoxyethylene fatty acid ester, sorbitan fatty acid ester ( Examples include sorbitan monooleate, sorbitan monopalmitate, sorbitan sesquioleate, etc.), polyoxyethylene sorbitan fatty acid ester, and glycerin fatty acid ester (glucerin monostearate, etc.).

Among these, glycerin fatty acid esters have an HLB of 2 to 6 and a melting point of 40 to 90°C, HLB of 2 to 8 and a melting point of 20
~80℃ sorbitan fatty acid ester, HLB 8-2
Particularly preferred are polyoxyethylene alkylphenyl ethers having a melting point of 0.0°C and 10°C to 50°C.

In addition to the above, as another example of synthetic pulp, about 8
Nonionic or anionic f! with a molecular weight of less than 000. Containing about 0.05-3% by weight of lubricant A (based on the weight of the polyolefin described below)
rted) polyolefin valves.

Blown polyolefin bulbs are extremely fine, highly finely divided, discontinuous fibrils made from polyolefins.
Large area (3-5 ci/g) and low density (
(approximately 0.2 g/cc), an average length of approximately 111, and an average diameter of approximately 5 to 40 microns.

Raw material polyolefins for injection polyolefin valves include polyethylene, polypropylene, ester propylene copolymers, propylene and 1-butene, 4-methyl-
Examples include copolymers with other 1-olefins such as 1-pentene and 1-pentene, and any of these polymers grafted with maleic anhydride or styrene compounds can also be used. Among these, polyethylene is preferred.

The wetting agent used may be one or more anionic or nonionic agents, such as polyoxyethylene monostearate, bis(hydroxyethyl)tallowamine, sodium dioctyl sulfosuccinate, polyoxyethylene diethylene chloride, etc. Examples include oleate ester, sodium lauryl sulfate, ethoxylated sorbitan laurate, and sodium alkyl sulfonate. Among these, ethoxylated sorbitan laurate and sodium alkyl sulfonate are preferred. Treatment with wetting agents is
This can be carried out by the known dipping method, spraying method, or by adding a wetting agent to the valve slurry as before.

In order to make the nonwoven fabric sheet used in the present invention, PP-
The PE composite fibers and polyolefin staple fibers are cut into appropriate lengths or beaten.

capped or beaten PP-PE composite fibers,
The polyolefin short fibers are mixed as a raw material fiber so that the polyolefin short fibers account for 10 to 80% by weight, preferably 30 to 60% by weight, based on the total weight, and a dispersant is added. It is added, stirred, and dispersed in water to obtain a raw material solution with a fiber concentration of about 1.5%.

As the dispersing agent used, molasses mucilage, sodium polyacrylate, polyethylene oxide, polyphosphoric acid, etc. are used.

Next, water is added to the raw material solution to increase the fiber concentration to approximately 0.6%.
After adding a binder as necessary, impurities and poorly dispersed fibers are removed using a screen, and paper is made using a paper machine.

Here, as the binder, heat-stable PVA fibers that are not heat-treated and not acetalized, etc., which are intermediates in the production of vinylon, can be used.

Further, as the paper machine, a known cylinder type, Fourdrinier type, or short screen type can be used. The formed nonwoven fabric sheet is dried with a dryer, heat set with a calendar, and wound up as a product.

The basis weight of the obtained nonwoven fabric sheet is 30 to 150 g/
m2, preferably 50 to 100 g/m". Also,
The apparent specific gravity is 0.2 to 0.9, preferably 0.4 to 0.7.
Good.

In the above manufacturing process, since the polyolefin short fibers have been subjected to hydrophilic treatment, they are easily dispersed in water and can be easily formed into paper. In addition, the sheet strength when wet is increased, and conveyance on a belt and peelability from the belt are improved.

Since the PP-PE composite fibers are mixed, heat setting has the advantage that it can be performed in a considerably wider temperature range than when polyethylene fibers are used alone. In other words, when the raw material fiber is a single polyolefin fiber, when heat-set at a temperature higher than the melting point of the polyolefin fiber,
The fibers melt and the nonwoven fabric becomes a film.
In the PP-PE composite fiber, even if the PE component melts, the PP component does not melt, and the nonwoven fabric as a whole does not become film-like.

Heat setting temperature is 130-160℃, preferably 1
The temperature is preferably 40 to 150°C.

As described above, by mixing bulky and porous P P -P E* synthetic fibers with polyolefin staple fibers and setting the polyolefin staple fibers to 10 to 80% by weight based on the total weight, a large number of micropores can be created. It has excellent water permeability and air permeability, and also has a high surface smoothness and excellent root blocking ability.

The odor of a non-woven fabric mixed with 10 to 50 weight percent of vegetable natural fibers includes bast fibers such as flax, timer, jute, and ramie, hard fibers (vein fibers) such as sisal hemp, Manila hemp, etc. Examples of the bulb include cellulose fibers such as cotton, bulbs, etc. Further examples of bulbs include wood bulbs, bamboo bulbs, craft bulbs, etc., and these vegetable natural fibers may be used alone or in combination.

Note that cellulose fibers such as acetate and rayon may be mixed, but since these are mainly composed of cellulose, they are similar to vegetable natural fibers.

In making the above-mentioned nonwoven fabric, these polyolefin fibers and vegetable natural fibers are cut into appropriate lengths,
Or be beaten. Generally, the fiber length to thickness ratio is 500.
Since papermaking cannot be performed with a fiber length of 500:1 or more, the fiber length is determined to be 500:1 or less in relation to the latitude.

canted or beaten polyolefin fibers,
Plant-based natural fiber contains 1 part of the total weight of plant-based natural fiber.
0 to 50% by weight, preferably 15 to 30% by weight, is mixed to obtain a raw material fiber, the raw material fiber is beaten with a beater, a dispersant is added, stirred, and dispersed in water to approximately 100% by weight. 1.5
% of the fiber concentration is obtained.

Next, as with the nonwoven fabric mentioned above, water is further added to the raw material solution to make the fiber concentration about 0.6%, and after adding a binder if necessary, impurities and poorly dispersed fibers are removed using a screen to make paper. Make paper using a machine.

In the above manufacturing process, since vegetable natural fibers are hydrophilic and easily dispersed in water, papermaking can be easily performed. In addition, the sheet strength when wet is increased, and conveyance on a belt and peelability from the belt are improved.

The formed nonwoven fabric sheet is dried with a dryer, heat-scented with a calendar, and rolled up as a product.
Since non-woven fabrics contain vegetable natural fibers, even if the synthetic fibers melt during heat setting, the vegetable natural fibers do not melt, and therefore the molten resin is retained in the vegetable natural fibers.
The nonwoven fabric as a whole does not become film-like.

As described above, this hand-woven fabric sheet is a non-woven fabric sheet with many micropores by mixing polyolefin fibers and vegetable natural fibers and making the vegetable natural fibers 10 to 50% by weight based on the total weight. It has excellent water permeability, air permeability, and root blocking ability.

Furthermore, the friction coefficient of the surface of the obtained nonwoven fabric sheet was large as shown in the table, which made it easier to cut. This seems to be due to the addition of vegetable natural fibers.

Example I As a PP-PE composite fiber, a composite fiber with a fineness of 3d (trade name: ES fiber, manufactured by Chisso ■) consisting of a core-sheath structure with a core of polypropylene and a sheath of polyethylene was used with a fiber length of 10~
50% by weight of polyolefin fiber cuffed to 20m, average fiber length Q, 9m, average fiber diameter IOμm
φ polyethylene valve [Product name: SWP (registered trademark)
UL 410, manufactured by Mitsui Petrochemical Industries) 50% by weight
was made using a cylinder paper machine to obtain a nonwoven fabric sheet, and one side of the nonwoven fabric sheet was printed black using gravure printing to obtain a light shielding rate of 80.
% sheets were obtained. Then, the strawberry seedlings were placed in soil with the black printed side facing up, and seedling pots with strawberry seedlings planted thereon were cultivated for three months from April to September. During that time, we applied water and fertilizer regularly, but the water did not accumulate on the sheet for a long time, and the roots did not pass through. During that time, we did not notice any swelling of the sheet due to weed growth, and the sheet was peeled off. There were hardly any weeds growing.

Example 2 50% by weight of PP-PE composite fiber and 40% by weight of polyolefin fiber, and 10% by weight of kraft valve with a fiber length of 3 to 6fl and a fineness of 415d as vegetable natural fiber.
A nonwoven fabric sheet with black printing on one side was obtained in the same manner as in Example 1, except that the mixture was mixed and paper-made. When this sheet was used as an underlay sheet for a strawberry seedling pot in the same manner as in Example 1, no water puddles, root penetration, or weed growth due to watering on the sheet was observed.

Incidentally, the characteristics of the nonwoven fabric sheets of Examples 1 and 2 are as follows.

Effects of the Invention According to the nonwoven fabric sheet of the present invention, it has water permeability and air permeability, does not inhibit the growth of weeds and does not interfere with the growth of plants grown in seedling pots, and the roots of seedlings do not disturb the soil beneath the sheet. It has the effect of being able to prevent the seeds from sticking to the plants.

Claims (4)

[Claims] (1) A nonwoven fabric sheet for growing plants that is placed under a seedling pot and has at least one side black. (2) The nonwoven fabric sheet for growing plants according to claim 1, which has a light shielding rate of 70% or more. (3) PP-P made of polypropylene and polyethylene
2. The nonwoven fabric sheet for growing plants according to claim 1, which is a nonwoven fabric made by mixing E composite fibers and short polyolefin fibers, and containing 10 to 80% by weight of the short polyolefin fibers based on the total weight. (4) The total polyolefin fiber according to claim 3 and the vegetable natural fiber are mixed, and the total weight of the vegetable natural fiber is 10 to 10% of the total weight.
The nonwoven fabric sheet for growing plants according to claim 1, which is a nonwoven fabric containing 50% by weight.