JPH0586165B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for producing a new seedling-raising paper that facilitates the growth of plant roots. [Prior Art and its Problems] Conventionally, bottomless pots for seedling raising, such as paper tube aggregates, have been used for raising seedlings. The paper used for this is a strong paper made of wood bulbs mixed with synthetic fibers and preservatives, and has the wet strength necessary for raising seedlings.
Attempts have been made to impart corrosion resistance. However, with kraft paper mixed with synthetic fibers, for example, in order to obtain the necessary wet strength as a pot until the end of seedling raising,
It is necessary to mix about 15 to 25% synthetic fiber,
After seedlings are raised and planted in the main field in pots, the roots of the plants are obstructed by the woody pulp fibers remaining in the mesh-like pores of the synthetic fibers, and their elongation is inhibited. For this reason, in Chinese cabbage, Chinese orchid, etc., which have weak rooting ability, growth has been particularly delayed after planting in the main field, causing problems such as reducing the effectiveness of seedling transplantation. Therefore, there are many cases where it is unavoidable to remove the paper pot body to form bare block seedlings at the time of planting in the main field, which not only results in a loss of labor but also causes the seedling's soil block to collapse due to the removal of the paper pot. However, there were disadvantages such as the fact that the effect of raising seedlings using a seedling pot was often lost. As an improvement method for these, a sheet in which a porous, corrosion-resistant, wet-strength synthetic fiber nonwoven fabric is pasted on one or both sides of kraft paper (for example, Japanese Patent Application Laid-open No. 58-60919, Japanese Patent Publication No. 59-22489) Public bulletin),
A sheet made by uniformly dispersing a small amount of corrosion-resistant synthetic fibers on the upper layer of kraft paper and then integrating the fibers with adhesive or heating (for example, JP-A-109524)
Alternatively, a sheet has been developed in which a wet paper web sheet of natural fibers and a porous sheet in which corrosion-resistant synthetic fibers are uniformly dispersed are made on the wire or blanket of a paper machine. However, even with such improved sheets, it has not been possible to obtain a sheet that has good rooting properties and extremely good wet strength when transplanted. [Object of the Invention] An object of the present invention is to provide a method for producing seedling-raising paper which, when used as a pot for raising seedlings, does not impair its strength during transplanting and further improves rooting properties. Another object of the present invention is to provide a novel seedling-raising paper comprising multiple layers of cellulose fibers and synthetic fibers, and a method for producing the same. [Specific Means for Solving the Problems] The method for producing seedling-raising paper of the present invention is to produce a wet paper sheet made mainly of cellulose fibers, and on at least one side of the wet paper sheet, a mesh net having a large number of micro-blocking portions having an arbitrary shape is used. A synthetic fiber sheet having a basis weight of 3 to 20 g/m ² and having openings is made into paper by a wet papermaking method. That is, the seedling raising paper obtained by the method of the present invention is a composite sheet consisting of a paper sheet such as kraft paper and a synthetic fiber sheet, and is characterized in that the synthetic fiber sheet has a large number of microscopic holes of arbitrary shapes. be. The wet paper machine for producing seedling paper of the present invention may be any paper machine that is used to produce ordinary paper, but the screen section of the paper machine for combining wet paper ( Use a type that combines two or more wire parts (wire parts) and has one of the meshes closed. For example, circular net - Fourdrinier, circular net -
Is it common to perform paper making using a combination paper machine such as a circular mesh or a circular mesh-slanted wire machine?
The combination types of paper machines are not limited to these, and can be used in combination as appropriate. Although there is no particular limitation on the fine shape of the mesh closing portions of the screen of the paper machine used to produce the seedling raising paper of the present invention, it is preferable that the closing portions are arranged evenly on the screen. Basically, it is desirable to increase the porosity as much as possible without reducing the burial strength. In reality, as a result of varying the size and pitch of the occluded area and examining the optimal pattern that balances burial strength and rooting ability, we found that the size of the micro occluded area was 7 mm ² ~
100mm ² , pitch 5-15mm, porosity of the net 20-70
% range is preferable, and it has been found that within these ranges, burial strength is maintained and rooting ability is improved. The seedling-raising paper of the present invention has a cellulose fiber sheet mainly made of cellulose fibers that maintains the strength properties required during molding and use for seedling-raising, and a synthetic fiber sheet that maintains corrosion resistance against soil at a stage after the start of seedling-raising. As if to force you, 2
This is a laminated paper that skillfully combines two functions. The sheet made of cellulose fiber, which is one of the sheets of the above-mentioned laminated sheet, may be any ordinary paper mainly made of wood bulbs and is not particularly limited. In addition to the wood pulp, a small amount of synthetic fibers other than cellulose fibers or various paper strength enhancers and chemicals commonly used in paper making may be mixed for the purpose of reinforcing the strength. However, it is preferable to mix it to the extent that it will corrode and decompose after a certain period of time while growing seedlings in the soil. Further, the synthetic fiber sheet is a sheet made of synthetic fibers having a basis weight of 3 to 20 g/m ² . In order to improve papermaking suitability, the same amount or less as synthetic fibers, preferably 10%
The following wood pulps may be mixed. If it is blended in an amount of 10% or more, the network structure of the synthetic fiber layer will decrease and rooting performance will deteriorate, which is not preferable. The synthetic fibers that can be used include corrosion-resistant polyvinyl alcohol-based, polyolefin-based, polyester-based, polyamide-based, polyacrylonitrile-based, and polyvinyl chloride-based synthetic fibers. In order to improve dispersibility and hydrophilicity in water, these synthetic fibers are treated with surfactants and thickeners such as polyethylene oxide, sodium polyacrylate, sodium tripolyphosphate, polyacrylamide, and polyethyleneimine. It can be used in combination with a dispersant. In addition to self-adhesive synthetic fibers, synthetic fibers can be mixed with fibrous binders such as wet heat adhesive polyvinyl alcohol, dry heat adhesive polyolefin, polyester, and ethylene-vinyl acetate copolymer. can be used. These fibers exhibit adhesive properties by heat from a dryer, but adhesive properties can also be imparted to them by pressure treatment under high pressure and high heat using a heat roll. Furthermore, powder of the above binder, PVA, acrylic resin, latex,
Synthetic fibers can also be bonded by spraying, impregnating or coating a water-resistant liquid binder such as vinyl acetate on-machine or with an off-coater. In addition, depending on the type of plants to be raised, the seedling raising paper of the present invention may contain preservatives, fungicides, insecticides,
Fertilizers, herbicides, growth hormones, dyes, and other substances that are effective in promoting plant growth may be added using appropriate methods such as mixing, impregnating, spraying, and coating on-machine during the papermaking and papermaking processes. can. Hereinafter, the method for manufacturing the seedling raising paper of the present invention will be explained. FIG. 1 is a schematic diagram of the manufacturing process of the seedling raising paper of the present invention, showing an example of forming the paper into two layers using a circular mesh and an inclined wire. A paper stock mainly composed of cellulose fibers dispersed in water supplied to a vat 2 from a paper stock inlet pipe 1 is drawn up in a cylinder 3 and picked up by a blanket 4 to form a wet paper web sheet 5. On the other hand, the synthetic fiber paper stock dispersed in water supplied from the inlet pipe 6 is placed on an inclined wire 7 with wire parts closed in an arbitrary pattern to form a synthetic fiber sheet 8 with holes almost identical to the pattern of the wire parts. The natural fiber wet paper paper sheet 5 on the previously formed blanket is picked up to form a laminated sheet 9. This laminated sheet 9 is dried with a dryer 10 to become a laminated paper 11 and a poly reel 12.
This results in the roll paper 13. In the above case, the synthetic fiber layer is laminated on one side, but it is also possible to use a three-layer seedling-raising paper in which synthetic fibers are laminated on both sides of the wet paper. When producing a seedling-raising container using the seedling-raising paper obtained according to the present invention, since the fibers of the synthetic fiber layer itself are fused together or glued together using glue, the seedling-raising paper is cut to a predetermined width. Then, the cut pieces are stacked so that the synthetic fiber layers are on the inside of each other, and both sides are heat-sealed or adhered with water-resistant glue to form a hexagonal or square pot body as shown in FIG. Such pot bodies may be used alone, or they may be glued together and used as a group pot body 14 as shown in FIG. 3. When manufacturing a group pot body, the outside of each pot body may be subjected to antiseptic treatment or root entanglement prevention treatment, etc., as appropriate. Examples of the present invention will be described below. Example 1 Seedling raising paper was produced using the paper machine shown in FIG. Introduction 50g/ ^m2 from wood valve (NUKP) with circular mesh
(solid content), and then vinylon fiber (VPB203×15 mm manufactured by Kuraray Co., Ltd.) and fibrous vinylon binder (VPB101×7 mm manufactured by Kuraray Co., Ltd.)
mm) in a ratio of 50:50, 0.5% by weight of dispersant (polyethylene oxide) was added to the fibers, and the slurry concentration was 0.02% by weight. 7mm, open area ratio 46.3%
A synthetic fiber sheet of 8 g/m ² was made using a slanted wire equipped with wires packed with pores, and after dehydration, it was dried at 120°C with a dryer and rolled up. The paper making speed at that time was 500 m/min. Table 1 shows the embedding strength of the resulting laminated paper and the evaluation of the rooting ability of seedlings grown in open and bottomless pots as shown in FIG. 3. For comparison, the above vinylon fiber (VPB203 manufactured by Kuraray Co., Ltd.)
×15mm), fibrous vinylon binder (Kuraray Co., Ltd.)
VPB101 x 7 mm) was mixed in a 50:50 ratio, and an 8 g/m ² synthetic fiber sheet was made using normal wire in a uniformly dispersed state, and a 50 g/m ² natural fiber (NUKP) was made.
Paper made into sheets (Comparative Example 1) and natural fibers (NUKP) with fibrous vinylon binder (Kuraray)
A 58 g/m ² synthetic fiber-mixed paper (Comparative Example 2) made by mixing 18% VPB103×7 mm (manufactured by Co., Ltd.) was evaluated in the same manner.
Compared to Comparative Examples 1 and 2, the sheet of this example had almost no difference in embedding strength and the rooting ability was greatly improved.

[Table] Example 2 In Example 1, the diameter and porosity of the wire's closing circles are the same; The same seedling growing test as in Example 1 was conducted on the seedling growing paper made under the same conditions as in Example 1, except that wires arranged in the same manner as in Example 1 were used. As a result, burial strength, rooting ability,
The handling suitability was the same as that of the seedling raising paper of Example 1. Example 3 In Example 1, as raw materials for the synthetic fiber sheet layer,
Using vinylon fiber (VPB103 x 10 mm, manufactured by Kuraray Co., Ltd.) and a fibrous binder (VPB101 x 7 mm, manufactured by Kuraray Co., Ltd.), the degree of clogging of the wire in the inclined wire section was changed as shown in Table 2. A synthetic fiber sheet layer having an amount of 6 g/m ² was formed and combined to obtain seedling raising paper. The obtained seedling growing paper was evaluated in the same manner as in Example 1. The results are shown in Table 2. Although the burying strength decreases as the pore size of the net increases, within the pore size range of the present invention, sufficient strength was maintained and the number of roots increased. Example 4 In Example 1, as raw materials for the synthetic fiber sheet layer,
Vinylon fiber (manufactured by Kuraray Co., Ltd., VPB103 x 10mm),
Seedling growing paper was obtained under the same conditions except that a binder (manufactured by Kuraray Co., Ltd., VPB101 x 7 mm) was used. However, the basis weight of the synthetic fiber sheet layer was changed as shown in Table 3, and the obtained seedling raising paper was evaluated in the same manner as in Example 1.

【table】

[Table] (Effects of the invention) The present invention makes it possible to produce seedling paper having an ultra-thin synthetic fiber layer of 10 g/m ² or less by combining papermaking, which was impossible using normal nonwoven fabric production technology. It became possible. Because the synthetic fiber layers have a structure with large voids, rooting properties are extremely good, which not only saves labor during transplanting, but also improves plant growth.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the manufacturing process of the seedling raising paper of the present invention,
Fig. 2 is a perspective view of a hexagonal pot body manufactured using the seedling raising paper of the present invention, Fig. 3 is a perspective view of a group pot body to which the pot bodies shown in Fig. 2 are glued together, and Figs. The figure shows a wire blinding pattern. 1...Paper stock introduction pipe, 2...Butt, 3...Circle mesh, 4...
Blanket, 5... Wet paper sheet, 6... Introducing pipe, 7... Inclined wire, 8... Synthetic fiber sheet, 9... Laminated sheet, 10... Dryer, 11... Laminated paper, 12
...Pope reel, 13...Wrap paper, 14...Collection pot body.

Claims (1)

[Claims] 1 A wet paper sheet mainly made of cellulose fibers, on at least one side of which is formed of a mesh having a large number of micro-blocking parts of arbitrary shape, with a basis weight of 3 to 3.
A method for producing seedling-raising paper, which comprises making a synthetic fiber sheet with holes of 20 g/m ² by a wet laminating method.