JP3291244B2 - Sapling protection cover - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tubular cover having both open ends for protecting planted seedlings.

[0002]

2. Description of the Related Art Conventionally, seedlings planted in mountain forests, etc.
In order to prevent being eaten by animals such as deer, rabbits and rats (animal damage), until the planted seedlings grow to some extent,
A method has been adopted in which the seedlings are raised by covering them with cylindrical tubular seedling protective covers having open ends.

[0003]

Since the above-described seedling protection cover is used by covering the seedling, it is naturally necessary to ensure light transmission into the cylindrical seedling protection cover. That is, the seedling protective cover needs to be non-colored or colored transparent or translucent so that light necessary for the growth of the seedlings existing in the protective cover is sufficiently irradiated.

On the other hand, since the above-mentioned seedling protective cover is placed outdoors for a long period of time (usually about five years), it is required to have some weather resistance. That is, even if it is left outdoors for a long period of time, it does not crack or lose its transparency (ideally,
(Even after five years, the total light transmittance is 70% or more).

[0005] Incidentally, synthetic resins such as polypropylene used as a material for a seedling protective cover generally have a tendency to deteriorate in weather resistance when transparency is improved (light transmittance is improved). Therefore, even in the above-described seedling protective cover, a property that maintains high transparency for a long period of time and does not cause cracking or the like has not been obtained, and weather resistance is sacrificed to some extent at the initial transparency. The reality is that the initial transparency is improved or the weather resistance is sacrificed to some extent.

The present invention provides a seedling protective cover that satisfies the transparency and weather resistance required for a seedling protective cover, maintains transparency for a long period of time, and is less likely to crack. is there.

[0007]

Means for Solving the Problems The seedling protective cover of the present invention made to solve the above-mentioned problems is provided with an ultraviolet absorber 0.01 to 0.2 per 100 parts by weight of a synthetic resin mainly composed of an olefin resin. It consists of a synthetic resin composition containing 0.1 to 5.0 parts by weight of a hindered amine light stabilizer, and has a total light transmittance of 7 in the protective cover before use.
The thickness of the sheet is 0.3 to 2.0 mm at 0% or more.

In order to obtain a seedling protective cover that satisfies the above characteristics, the synthetic resin is composed of 50 to 90% by weight of random polypropylene and 10 to 50% by weight of block polypropylene or / and high density polyethylene. A mixed synthetic resin to be used, a copolymer resin of random polypropylene and block polypropylene, or a polyethylene polymerized by using a metallocene catalyst and / or a polypropylene polymerized by using a metallocene catalyst; Polyethylene 5
It is desirable to use a mixed synthetic resin composed of 0 to 10% by weight.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a seedling protection cover according to the present invention. FIG. 1 is a diagram showing a state in which an example of a seedling protective cover of the present invention is used, and reference numeral 1 in the drawing denotes an example of a seedling protective cover of the present invention, which is denoted by T.
Indicates a seedling.

The seedling protection cover 1 shown in FIG. 1 has a cylindrical shape having a regular hexagonal cross section and both ends open. The seedling protective cover 1 has an inner diameter (diagonal length of a regular hexagon) of about 120 mm and a length of about 1400 mm.
(However, it is omitted in FIG. 1).

The shape of the seedling protective cover in the present invention is not particularly limited. For example, the same shape as a conventionally used seedling protective cover, such as a cylindrical one having a circular cross section, is used. It can be. Also, regarding the inner diameter and length of the seedling protection cover,
It can be arbitrarily selected according to the type of seedlings. Still further, the seedling protective cover of the present invention may have one end or both ends for the purpose of forming a ventilation hole for ensuring air permeability to the inside thereof, or for ensuring shape retention. It may be one having a folded portion formed thereon, or one having an embossed aperture such as satin or silk on the surface.

As shown in FIG. 1, the seedling protective cover of the present invention is covered with a seedling or the like so that its lower end is buried in the soil, but it is easily blown off by wind or the like. Therefore, in the same manner as when the conventional seedling protection cover is installed, the seedling protection cover is fixed to the splint erected so as to be adjacent to the seedling protection cover using a string or wire (FIG. 1).
Here, illustrations of splints, strings, and the like for fixing the seedling protection cover 1 are omitted).

The seedling protective cover 1 shown in FIG. 1 is obtained by extruding a synthetic resin composition mainly composed of polypropylene having a composition as described below from a T-die of an extruder so as to have a thickness of 0.7 mm. A non-colored or colored transparent polypropylene sheet having a total light transmittance of 70% or more, obtained by forming a sheet, is used as a material, and the transparent polypropylene sheet is punched into a predetermined shape, and a fold line is formed at a predetermined position. It is bent at the fold line position, a predetermined portion is appropriately bonded using an adhesive, or fixed by means such as ultrasonic welding, and formed into a cylindrical shape having a regular hexagonal cross section with both open end faces. It is obtained.

As described above, the seedling protective cover of the present invention is formed of a synthetic resin composition mainly composed of an olefin resin. This synthetic resin composition contains 0.01 to 0.2 parts by weight, preferably 0.05 to 0.2 parts by weight of an ultraviolet absorber per 100 parts by weight of a synthetic resin mainly composed of an olefin resin.
0.1 parts by weight and 0.1 parts by weight of a hindered amine light stabilizer
To 5.0 parts by weight, preferably 0.2 to 2.0 parts by weight. When the amount of the ultraviolet absorber and the hindered amine light stabilizer is less than the above range, it is not possible to obtain a seedling protective cover that maintains transparency for a long period of time and hardly causes cracks, etc. If the amount of the absorber and the hindered amine light stabilizer exceeds the above range, not only does the cost rise, but also the added ultraviolet absorber and the hindered amine light stabilizer bloom on the surface, lowering the transparency and reducing dust. Etc. also tend to adhere.

The seedling protective cover of the present invention needs to have a total light transmittance of 70% or more into the protective cover before use. To obtain a seedling protective cover satisfying such characteristics, As the above synthetic resin, a mixed synthetic resin composed of 50 to 90% by weight of random polypropylene and 10 to 50% by weight of block polypropylene or / and high density polyethylene, a copolymer resin of random polypropylene and block polypropylene, or metallocene 50-90% by weight of polyethylene polymerized using a catalyst or / and polypropylene polymerized using a metallocene catalyst;
It is desirable to select and use a mixed synthetic resin composed of 10 to 10% by weight.

The random polypropylene in the mixed synthetic resin mainly composed of the random polypropylene is as follows:
Generally, it refers to a product obtained by random copolymerization of propylene and ethylene, and a commercially available product can be used. Although this random polypropylene has an advantage of being superior in transparency as compared with other polypropylenes, when a seedling protection cover is formed using only this random polypropylene as a synthetic resin, a seedling protection cover is formed. Is insufficient. Therefore, block polypropylene and / or high-density polyethylene are mixed with the above-mentioned random polypropylene. However, if the mixing ratio of these is too high, there is a problem that transparency is deteriorated. Therefore, when the above-mentioned mixed synthetic resin is used to obtain the seedling protective cover of the present invention, the above-mentioned random polypropylene is 50 to 90% by weight, the block polypropylene or / and the high-density polyethylene is 10 to 50% by weight, especially Preferably, the content of the random polypropylene is 70 to 85% by weight, and the content of the block polypropylene and / or the high density polyethylene is 15 to 30% by weight.

The above-mentioned block polypropylene is generally obtained by copolymerizing propylene and ethylene in a block shape, and any commercially available block polypropylene can be used.
Also, high density polyethylene generally has a density of 0.9.
It is polyethylene of about 55 to 0.965 g / cm ³ , and a commercially available polyethylene can be used.

Further, the copolymer resin of random polypropylene and block polypropylene has both the characteristics of the above-mentioned random polypropylene and the characteristics of the block polypropylene, and secures the strength as a seedling protective cover and the transparency. Can be done.

Furthermore, polyethylene or polypropylene polymerized using a metallocene catalyst in a mixed synthetic resin mainly composed of polyethylene and / or polypropylene polymerized using the above-mentioned metallocene catalyst is used when polymerizing. A metallocene catalyst is used as the catalyst to be used, and a commercially available catalyst can be used.

The above-mentioned mixed synthetic resin mainly composed of random polypropylene, a copolymer resin of random polypropylene and block polypropylene, or a mixed synthetic resin mainly composed of polyethylene and / or polypropylene polymerized using a metallocene catalyst. In the range that does not impair the properties required for the obtained seedling protective cover, polymers other than the above, for example, low-density polyethylene, linear low-density polyethylene, ultra-low-density polyethylene,
Polyethylene such as medium-density polyethylene; ethylene-based copolymers such as ethylene-vinyl acetate copolymer, ethylene- (meth) acrylate copolymer, and ethylene-α-olefin copolymer; polybutene, butene-α-olefin Butene polymers such as copolymers; olefin rubbers; olefin thermoplastic elastomers;
Hydrogenated rubber such as butadiene rubber and hydrogenated styrene-isoprene rubber may be mixed.

Specific examples of the ultraviolet absorber added to the above synthetic resin include a benzoate ultraviolet absorber such as resorcinol monobenzoate; 4-hydroxy-4-methoxybenzophenone and 2-hydroxy-4-methoxybenzophenone. , 2-hydroxy-4-methoxy-4 '
-Methylbenzophenone, 2-hydroxy-4-octoxybenzophenone, 4-dodecyloxy-2-hydroxybenzophenone, 2-hydroxy-4-stearyloxybenzophenone, 2-hydroxy-4-benzyloxybenzophenone, 2,2'-dihydroxy −4
4'-dimethoxybenzophenone, 2,4-dihydroxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-n
-Octoxybenzophenone, 2,2 ', 4,4',-
Benzophenone ultraviolet absorbers such as tetrahydroxybenzophenone; benzotriazole ultraviolet absorbers such as 2- (2'-hydroxy-5'-methylphenyl) benzotriazole and substituted hydroxyphenylbenzotriazole; phenyl salicylate, 4-t-butyl One or two or more selected from salicylic ester ultraviolet absorbers such as phenyl salicylate, pt-butylphenyl salicylate, p-octylphenyl salicylate and salicylic acid derivatives; cyanoacrylate ultraviolet absorbers; be able to.

As the hindered amine light stabilizer to be added to the above synthetic resin, for example, one or more selected from those shown in Chemical formula 1 can be used in combination.

[0023]

Embedded image

The synthetic resin mainly composed of an olefin resin in the present invention may further contain, if necessary, an antistatic agent, an antioxidant, a lubricant, an inorganic filler, in addition to the above-mentioned ultraviolet absorber and hindered amine light stabilizer. Various additives such as a coloring agent such as a pigment may be added. As these various additives, those conventionally used as additives to synthetic resins mainly composed of olefin resins can be used,
The amount of addition does not need to be particularly different from the case where it is conventionally added to a synthetic resin mainly composed of an olefin resin.

The synthetic resin composition mainly composed of an olefin resin composed of the above-mentioned synthetic resin such as polypropylene, an ultraviolet absorber, a hindered amine light stabilizer and various additives which are added as required, is extruded. The sheet is formed to a predetermined thickness by means such as pushing out from a T-die of the machine. The thickness of this sheet depends on the type of synthetic resin used, etc.
It depends on the size of the seedling protection cover to be obtained, etc., and is not particularly limited, but is 0.3 to 2.0 m.
It is desirable that the thickness be in the range of about m, particularly in the range of about 0.5 to 1.5 mm. If the thickness of the sheet is too thin, there is a concern that the strength is reduced and the shape retention is deteriorated, and that the weather resistance is reduced and cracks and the like are likely to occur.
If the thickness of the sheet is too large, the weather resistance and strength are sufficient, but there is a concern that the transparency is reduced, the weight is increased, and the labor required for transportation is increased.

The sheet obtained as described above is punched into a predetermined shape and a fold line is formed at a predetermined position. After the sheet is bent at the fold line position, a necessary portion is subjected to ultrasonic welding or adhesive. To form a cylindrical seedling protective cover with both ends open.

The method for producing a seedling protective cover of the present invention is not limited to the above method. For example, when a cylindrical seedling protective cover is to be obtained, the above synthetic resin composition is mixed with a circular die (circular). It is also possible to extrude the die into a cylindrical shape.

[0028]

EXAMPLES Hereinafter, the present invention will be described with reference to specific examples, but the seedling protective cover of the present invention is not limited to the following examples.

[Examples 1 to 4, Comparative Examples 1 to 3, Reference Example 1]
~ 2] A synthetic resin composition mainly composed of polypropylene having the composition shown in Table 1 was extruded from a T-die of an extruder to obtain a sheet having a thickness of 0.7 mm. The obtained sheet is punched into a predetermined shape, a fold line is formed at a predetermined position, and the sheet is bent and ultrasonically welded to obtain a seedling protection cover having the same size and shape as the seedling protection cover 1 shown in FIG. Was. About the obtained seedling protective cover, while measuring the total light transmittance in the protective cover, using a super UV tester manufactured by Iwasaki Electric Co., Ltd., irradiating for 100 hours at an irradiation energy intensity of 60 mv / cm ² , and then 200 After the irradiation for 300 hours, the weather resistance of each seedling protection cover is evaluated by checking for the occurrence of cracks and measuring the total light transmittance after irradiation for 300 hours (corresponding to the state where the device is installed outdoors for 5 to 7 years). did. Further, as Reference Examples 1 and 2, the same test was performed on commercially available seedling protection covers A and B. The results are shown in Table 1.

[0030]

[Table 1]

Examples 5 to 6 and Comparative Examples 4 to 5 A synthetic resin composition mainly composed of an olefin resin shown in Table 2 was extruded from a T-die of an extruder to form a sheet having a thickness of 0.7 mm. Obtained. While punching the obtained sheet into a predetermined shape,
A fold line is formed at a predetermined location, and after bending, it is ultrasonically welded to have the same size as the seedling protection cover 1 shown in FIG.
A shaped saplings protective cover was obtained. Further, with respect to the obtained seedling protective cover, the total light transmittance into the protective cover was measured in the same manner as described above, and the weather resistance was evaluated. The results are shown in Table 2.

[0032]

[Table 2]

[0033]

As described in detail above, the seedling protective cover of the present invention is superior in weatherability and has been used outdoors for a long period of time, even though it has higher transparency than conventionally available seedling protective covers. Even if it is installed, cracks are unlikely to occur and transparency is not significantly reduced. Therefore, an environment suitable for promoting the growth of seedlings can be provided in the seedling protection cover as compared with the case where a commercially available seedling protection cover is used.

[Brief description of the drawings]

FIG. 1 is a diagram showing a use state of a seedling protection cover of the present invention.

[Explanation of symbols]

 1 Sapling protection cover T Sapling

Claims (3)

(57) [Claims] 1. A protective cover for a cylindrical seedling, which is formed from a synthetic resin composition mainly composed of an olefin resin to be used to cover a seedling and is open at both ends, wherein the protective cover is inserted into the protective cover before use. 70% total light transmittance
The synthetic resin composition forming the seedling protection cover is randomly selected.
50-90% by weight of polypropylene and block polypropylene
Pyrene or / and high density polyethylene 10-50% by weight
And a synthetic resin 10
A synthetic resin composition containing 0.01 to 0.2 parts by weight of an ultraviolet absorber and 0.1 to 5.0 parts by weight of a hindered amine light stabilizer per 0 parts by weight, and having a sheet thickness of 0.3 to 2. 0
Seedling protection cover in mm . 2. A cylindrical seedling protective cover having an opening at both ends, which is formed from a synthetic resin composition mainly composed of an olefin resin used for covering a seedling, wherein the protective cover is inserted into the protective cover before use. 70% total light transmittance
The synthetic resin composition forming the seedling protection cover is randomly selected.
Copolymer resin of polypropylene and block polypropylene
, And the synthetic resin per 100 parts by weight, UV absorber 0.01 to 0.2 parts by weight, with a hindered amine light stabilizer synthetic resin composition comprising 0.1 to 5.0 parts by weight, of the sheet
A seedling protection cover having a thickness of 0.3 to 2.0 mm . 3. A cylindrical seedling protective cover having an opening at both ends, which is formed from a synthetic resin composition mainly composed of an olefin resin used for covering a seedling, wherein the protective cover is inserted into the protective cover before use. 70% total light transmittance
The synthetic resin composition forming the seedling protection cover is a metallose
Polyethylene and / or polymerized using a catalyst
Polymerized using a metallocene catalyst
50-90% by weight of len and 50-1 of high density polyethylene
0% by weight of the mixed synthetic resin, and the ultraviolet absorber 0.01 to 0.1% per 100 parts by weight of the synthetic resin.
2 parts by weight, hindered amine light stabilizer 0.1 to 5.0
In the synthetic resin composition containing parts by weight , the thickness of the sheet is 0.3 to
Seedling protection cover that is 2.0 mm .