JPH11279295A - Sheetlike material and sheetlike molded product containing lactone resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sheetlike material, a sheetlike molded product and an agricultural sheet suitable for producing a roof sheet for plastic greenhouse culture, a mulching sheet for laying soil and an agricultural sheet used for covering a nursery bed, especially an agricultural mulching sheet in order to improve the harvesting technique of field crops. SOLUTION: The characteristic of this sheetlike composition is to contain a lactone resin, especially a poly ε-caprolactone subjected to radiation exposure treatment as a constituent component. The sheetlike molded product is prepared by impregnating a paper with a nonaqueous solution or an emulsion slurry of the lactone resin subjected to the radiation exposure treatment. Furthermore, the agricultural sheet is composed thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet-like article, a sheet-like molded article, and an agricultural sheet containing a lactone resin which has been subjected to a radiation irradiation treatment. More specifically, manufacture of roof sheets for house cultivation, multi-sheets for laying soil, agricultural sheets used for covering for seedling allowances, especially multi-sheets for agricultural use, especially for improving harvesting techniques for agricultural crops such as rice and fruits. The present invention relates to a sheet-like material, a sheet-like molded product, and an agricultural sheet suitable for the present invention.

[0002]

2. Description of the Related Art Various types of sheets or thick films are used as agricultural sheets in various directions. In particular, agricultural multi-sheets are laid on the ground to control changes in soil temperature and to suppress the growth of weeds. It is used for the purpose of increasing the yield of crops by functions such as prevention of dissipation of soil nutrients. Conventional agricultural sheets are mainly used in addition to polyolefins typified by polyethylene, vinyl chloride resin, ethylene vinyl acetate resin, etc., while being transparent or colored in black, silver, white, or the like. Have been.

[0003] Although these sheets themselves are made of general-purpose synthetic resin, they are relatively inexpensive, but removal, storage and reuse of dirt after use of these sheets having a large area are complicated, and tear propagation strength is high. Because it is not high, it is often damaged after use, and it tends to be discarded after each use. However, the materials of these sheets do not readily degrade chemically or biochemically even when exposed to the weather on the soil or buried in the soil and left in the natural environment, so they remain as waste forever There is a problem. As a treatment method that does not leave waste, incineration treatment is the simplest, but the incinerator is often damaged by the high calorific value of synthetic resin during combustion, and harmful substances may be generated due to combustion. Therefore, this method is not always preferable.

[0004] For this reason, as a multi-sheet for agriculture, etc., which has been used for a long period of time in a natural environment, is easily soiled, and is easily broken and difficult to recover and reuse, the necessary period has passed. After that, the strength of the sheet weakens, and when it is thrown into the soil, it is completely decomposed by microorganisms, and a sheet that does not require recovery processing is required.Caprolactone, including fully biodegradable fibrous paper, is required. The use of resins and the like is being studied. Generally, paper itself has low strength, including wet strength, and cannot withstand use as it is, and combinations with various biodegradable resins are introduced. However, these biodegradable resins themselves are inferior in strength to conventional general-purpose synthetic resins, and are not in a state where they can be widely used as agricultural sheets.

[0005]

Accordingly, the present invention can be used for general purposes in consideration of the composite with paper, etc.
It is an object of the present invention to provide a sheet, a sheet molded product, and an agricultural sheet having excellent physical strength such as tear strength and high biodegradability.

[0006]

Means for Solving the Problems The present inventor has found that when a lactone resin, which is biodegradable and water-insoluble, is irradiated with radiation, the strength is improved and the biodegradability is also improved. It has no effect on biodegradability even when used together with a state-of-the-art material, and furthermore, it has been found that various agricultural sheets, especially multi-sheets, can be used as high-strength sheets that can withstand sufficient use.
The present invention has been reached.

The gist of the present invention is as follows. The first aspect of the present invention relates to a sheet-like material containing, as a constituent, a lactone resin that has been subjected to a radiation irradiation treatment. Second embodiment of the present invention
The present invention relates to the sheet material according to the first aspect of the present invention, wherein the lactone resin is poly-ε-caprolactone. Third of the present invention
The present invention relates to a sheet-like molded product formed by impregnating paper with a non-aqueous solution or an emulsion slurry of the lactone resin according to the first or second aspect of the present invention to form a sheet. A fourth aspect of the present invention relates to a sheet-like molded product obtained by mixing the lactone resin according to the first or second aspect of the present invention with paper fibers. A fifth aspect of the present invention relates to a sheet-like molded product obtained by laminating a film comprising the lactone resin according to the first or second aspect of the present invention. A sixth aspect of the present invention is the first or second aspect of the present invention.
The present invention relates to a sheet-like molded product comprising a mixture of a powdery and / or fibrous material and a powdery and / or fibrous material other than the lactone resin. A seventh aspect of the present invention relates to a sheet-like molded product obtained by coating the lactone resin according to the first or second aspect of the present invention on a sheet-like material formed from a powdery and / or fibrous material. An eighth aspect of the present invention relates to an agricultural sheet made of impregnated paper impregnated with the lactone resin according to the first or second aspect of the present invention.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described specifically. The lactone resin used in the present invention has ε
-Caprolactone, 4-methylcaprolactone, 3,
Various methylated caprolactones such as 5,5-trimethylcaprolactone, 3,3,5-trimethylcaprolactone, β-propiolactone, γ-butyrolactone, δ-
Examples include valerolactone, a homopolymer of enantholactone, a copolymer of two or more of these monomers, and a mixture of these homopolymers or copolymers. In particular, those which do not soften at room temperature are preferable, and from this viewpoint, poly ε- having a high molecular weight and a melting point of 50 ° C. or more, which can easily obtain stable performance.
Caprolactone (sometimes referred to as polycaprolactone) is preferred. Hereinafter, the lactone resin according to the present invention will be mainly described using polycaprolactone as a typical example. The polycaprolactone includes, besides a homopolymer of ε-caprolactone, a copolymer using a comonomer such as valerolactone, glycolide, or lactide, and the number average molecular weight is preferably 10,000 to 300,000. 40,000 in terms of a good bridge
~ 150,000 are particularly preferred. First of the present invention
To the lactone resin used in the eighth to the second polyε
-Caprolactone is water-insoluble and can be impregnated into paper or fibrous substances, but the lactone resin alone or together with other biodegradable resins may constitute a sheet or a molded product. Other biodegradable resins are similarly water-insoluble,
Those that can impregnate paper or the like are preferable. Accordingly, a sheet-like material or a molded product made of a resin composition obtained by kneading a polyolefin with a lactone resin having good biodegradability is not preferable because non-degradable components remain after biodegradation.

The other biodegradable resin is not particularly limited as long as it can be mixed with a lactone resin and formed into a sheet as a composition, and various known resins are used. Examples of such a biodegradable resin include biodegradable polyester resins such as synthetic polylactic acid, polyethylene succinate, and polybutylene succinate. A polyester resin synthesized from a high molecular weight aliphatic dicarboxylic acid and a low molecular weight aliphatic diol, including those having a molecular weight improved by a diisocyanate compound), and a biodegradable cellulose ester. , Polypeptide, starch and the like. These can be used alone or in combination of two or more. Examples of the biodegradable cellulose ester include organic acid esters such as cellulose acetate, cellulose butyrate, and cellulose propionate; inorganic acid esters such as cellulose nitrate, cellulose sulfate, and cellulose phosphate; cellulose acetate propionate, and cellulose acetate butyrate And hybrid esters such as cellulose acetate phthalate and cellulose nitrate acetate. These cellulose esters can be used alone or in combination of two or more. Among these cellulose esters, organic acid esters, particularly cellulose acetate, are preferred. Examples of the polypeptide include polyamino acids and polyamide esters. As starch, raw starch,
Modified starches and mixtures thereof. Examples of the raw starch include corn starch, horse bell chopsticks starch, sweet potato starch, wheat starch, cassava starch, sago starch, tapioca starch, rice starch, legume starch, kuzu starch, bracken starch, lotus starch, and heishi starch. Examples of the starch include physically modified starch (α-starch, fractionated amylose, wet heat-treated starch, etc.), enzyme-modified starch (hydrolyzed dextrin, enzyme-decomposed dextrin, amylose, etc.), chemically-modified starch (acid-treated starch, hypochlorite). Acid-oxidized starch, dialdehyde starch, etc.) and chemically modified starch derivatives (esterified starch, etherified starch, cationized starch, cross-linked starch, etc.). Among the above, as the esterified starch, acetic esterified starch,
Succinic esterified starch, nitrated esterified starch, phosphorylated esterified starch, urea phosphorylated esterified starch, xanthated esterified starch, acetoacetated esterified starch, etc .; etherified starch includes allyl etherified starch;
Methyl etherified starch, carboxymethyl etherified starch, hydroxyethyl etherified starch, hydroxypropyl etherified starch, etc .; Examples of the cationized starch include a reaction product of starch and 2-diethylaminoethyl chloride, and starch and 2,3-epoxypropyltrimethyl. Ammonium chloride reactant and the like; Examples of the crosslinked starch include formaldehyde crosslinked starch, epichlorohydrin crosslinked starch, phosphoric acid crosslinked starch, acrolein crosslinked starch and the like.

The sheet-like material or sheet-like molded product of the present invention may contain, if necessary, a resin component other than a photodegradation or biodegradation accelerator, the lactone resin and the aliphatic polyester resin (for example, ε-caprolactone and ε-caprolactone). -Polyamide ester resins, polyamino acid resins, ethylene copolymers and other polyolefins synthesized from caprolactam, hydrogenated styrene butadiene rubber, polyurethane, polyamide, polyhydroxybutyrate, etc.), and natural polymers other than the starch (for example, , Polysaccharide-based polymers, cellulose-based polymers, protein-based polymers, etc.), fine powder particles having a diameter of 50 μm or less, manufactured from paper, heat stabilizers, extenders,
Fillers such as talc and calcium carbonate, lubricants, coloring agents, flame retardants, water resistance agents, autoxidizers, UV stabilizers, crosslinking agents,
Antibacterial agents, herbicides, antioxidants, deodorants and the like can be added. These can be added after irradiation.

The lactone resin or the resin composition containing the lactone resin used in the sheet-like article or sheet-like molded article of the present invention is prepared by subjecting a lactone resin alone to radiation irradiation in advance and using the lactone resin as it is. In addition to the resin composition obtained by adding a biodegradable resin, a lactone resin and a biodegradable resin may be mixed and then used after irradiation treatment. Alternatively, the radiation irradiation treatment may be performed during the molding of the sheet-like material or the sheet-like molded product. In order to improve biodegradability, it is preferable to use a lactone resin or a resin composition containing a lactone resin, for example, pellets, obtained by irradiation treatment. When the irradiation is performed during the molding of the sheet-like material, the lactone resin is once irradiated with heat while melting at a temperature equal to or higher than the melting point, while the crystals of the lactone resin are still in an amorphous state even when cooled. It is efficient because a high degree of crosslinking can be obtained at the irradiation dose. Of course, the irradiation treatment may be performed after the molded lactone resin is crystallized.

The lactone resin, especially the caprolactone resin constituting the sheet-like material or the sheet-like molded product according to the present invention may be irradiated alone or as a composition with the other biodegradable resin components as described above. Must have been processed. Hereinafter, the case where the lactone resin is mainly used alone will be described as an example, but the same applies to the case of the composition containing the lactone resin. Radiation irradiation treatment of lactone resin is widely performed industrially for modification by crosslinking and the like, and α-rays, β-rays, γ-rays, X-rays, electron beams, ultraviolet rays, etc. are used as radiation sources. Can be used, but cobalt 60
In addition to γ-rays and electron beams, X-rays are more preferable. Above all, γ-rays or electron beam irradiation treatment using an electron accelerator are most convenient for introducing a bridge structure.

The radiation irradiation treatment according to the present invention can be carried out on a powder or pellet of a lactone resin itself, of which polycaprolactone is a typical example, or of a composition thereof. The temperature during the irradiation treatment is not particularly limited, and may be room temperature, or may be a cooling process during molding as described above.

The crosslinking reaction, which is an effect of the radiation treatment of the lactone resin in the present invention, occurs even with a small irradiation dose, and is effective even at about 15 kGy at room temperature, and the degree of crosslinking increases as the dose increases. The radiation dose rate is not particularly limited, but when a high degree of crosslinking is required, a higher dose rate is preferable because the production efficiency is improved. The atmosphere at the time of the radiation treatment is not particularly limited, but it is advantageous that the lower the oxygen concentration, the smaller the irradiation dose.

When the raw material is irradiated with radiation, the melt-flow index (MI) of the irradiated lactone resin (measured at 190 ° C. under a load of 2160 g)
Is preferably from 0.01 to 10 g / 10 min, and particularly preferably from 0.3 to 3 g / 10 min. The degree of crosslinking of the lactone resin is 10% or less, preferably 0.1 to 1%, in terms of the gel fraction described below. When the irradiation treatment is performed during or after the molding, unlike the case where the irradiation treatment is performed on the molding raw material, the melt fluidity has little or no problem. Conditions can be set to perform a high degree of crosslinking.
In this case, the gel fraction of the lactone resin is usually 1 to 90%.
Range.

As a method of obtaining a sheet-like molded product having a biodegradable resin as a component according to the third to seventh aspects of the present invention, a preferred method is selected depending on the characteristics of the lactone resin used. The method may be used, and is not particularly limited, but includes the following several methods. First, a sheet-like molded article obtained by impregnating a sheet-like substance made of a fibrous substance such as paper or pulp with a solution or emulsion obtained by dissolving the lactone resin obtained by the above-mentioned irradiation treatment in an organic solvent (third aspect of the present invention) Specifically, a method of immersing a sheet material made of a fibrous substance such as paper or pulp into a resin solution or emulsion,
A resin solution or an emulsion is applied to the surface of a sheet made of a fibrous substance such as paper or pulp, and the lactone resin component is incorporated by a method such as spraying, and then the solvent or dispersion medium is dried to form a sheet. And a method for obtaining a shaped article. Using a lactone resin that has not been subjected to radiation treatment, after obtaining a sheet-like molded product in the same manner,
The sheet-shaped molded product may be subjected to a radiation irradiation treatment.

The concentration of the lactone resin in the above-mentioned solution or emulsion used depends on the solution viscosity based on the type of the lactone resin used, but is usually 3 to 30% by weight, preferably 5 to 20% by weight. is there. When the lactone resin concentration in the solution or emulsion is less than 3% by weight, the impregnation rate is high, but the wet strength of the completed sheet-like molded product may not always be sufficient. Conversely, when the concentration of the lactone resin exceeds 30% by weight, the amount of the resin to be impregnated is liable to be excessively large, and when a solution is used, the viscosity becomes too high and the impregnation operation becomes difficult. There is. The type of the organic solvent is arbitrarily selected depending on the lactone resin used.

As another method, there is a method of producing a sheet molding (fourth aspect of the present invention) in which a lactone resin is mixed during papermaking. Specifically, this is a method of mixing a radiation-treated lactone resin powder or a fibrous material thereof and a paper raw material, and then heating and melting the resin to obtain a sheet-like molded product. Using a lactone resin that has not been subjected to radiation irradiation, after obtaining a sheet-like molded product in the same manner, the sheet-like molded product may be subjected to radiation irradiation treatment.

A method for obtaining a sheet-like molded product (fifth aspect of the present invention) obtained by laminating a lactone resin obtained by a radiation irradiation treatment includes a method of forming a thin film of a lactone resin on a sheet made of a fibrous substance such as paper or pulp. And a method in which the lactone resin powder is sprayed on the surface of a sheet made of a fibrous substance such as paper or pulp, and then fused by a hot press.

Further, as a method for obtaining a sheet-like molded product (the sixth and seventh aspects of the present invention) having the above-mentioned irradiated lactone resin as a constituent component, a powdery and / or fibrous lactone resin and another lactone resin may be used. A method of heating a mixture of a powdery and / or fibrous material, melting a resin component, and integrally molding into a sheet to obtain a molded product, and further into a sheet-like material comprising a powdery and / or fibrous material. Examples of the method include a method in which a lactone resin that has been subjected to a radiation irradiation treatment is obtained by coating the lactone resin with the above method or the like. Using non-irradiated lactone resin,
Similarly, after obtaining a sheet-shaped molded product, the sheet-shaped molded product may be subjected to a radiation irradiation treatment. The other powdery and / or fibrous materials mentioned here may be products usually used for other purposes, but in particular, when used in the agricultural field where low cost is required, for example, sawdust. , Rice husks, pulverized materials obtained from plants, and powdery or fibrous wastes from the papermaking process are preferably used.

Next, as a method for obtaining an agricultural sheet (eighth of the present invention) comprising an impregnated paper impregnated with the lactone resin obtained by the above-mentioned radiation irradiation treatment, generally, the radiation irradiation treatment is carried out. A method of immersing the paper in a solution or emulsion of the lactone resin, applying the solution or emulsion of the lactone resin to a paper roll by applying the solution or emulsion of the lactone resin to the paper by spraying, and then adding a solvent or a dispersion medium to the paper. A method of drying, a method of mixing the lactone resin powder or the fibrous material subjected to the above treatment and a paper raw material, and then heating and melting the resin; a method of spraying the resin powder on paper, and a method of heating and melting the resin; For example, a method of fusing the thin film to paper with a hot press may be used. When a lactone resin is used in combination with another biodegradable resin, the impregnation method is convenient. After using a lactone resin that has not been subjected to radiation treatment, an agricultural sheet may be obtained in the same manner, and then the sheet may be subjected to radiation treatment.

On the other hand, the paper used for the sheet-like material, sheet-like molded product, and agricultural sheet according to the present invention is not particularly limited, but the thickness is such that the impregnation is not impaired. It is preferable to have a thickness that does not impair various workability, particularly agricultural workability. For example, from the viewpoint of agricultural workability, a thickness approximately equal to that of a polyolefin sheet currently used is preferable. Specifically, it is 1 to 0.01 mm, preferably 0.3 to 0.05 mm. If it is too thick, the length per roll will be short, and laying on long ridges will be 1
Rolls cannot be used, and if too thin, the strength is insufficient, and the amount of impregnated resin must be increased. Therefore, it is preferable that the basis weight also corresponds to a thickness of 0.05 to 1 mm. Note that the paper may include a fertilizer and an agricultural chemical component such as humus and bark therein.

The coating amount, impregnation amount or lamination amount of the irradiated lactone resin is 0.5 to 20 g / m ² , preferably from the viewpoint of strength, workability and economy.
1 to 5 g / m ² . Since the strength of the paper greatly varies depending on the raw material of the paper and the manufacturing method, it is preferable to determine the required paper strength in combination with the strength of the lactone resin used.

Regarding the molecular weight of the lactone resin to be used, it is preferable to use a resin having a high molecular weight, since a desired strength can be obtained with a small amount of resin used. For example, taking polycaprolactone as an example, a resin having a relative viscosity of less than 1.4 before the irradiation treatment has a small reinforcing effect, and therefore it is preferable to use a resin having a relative viscosity higher than 1.4. The paper impregnated with the lactone resin in this way has an increased strength when wet with water, and can be used as an agricultural sheet.

In general, in the use of agricultural multi-sheets, since the crop is small during the first three months of the use period, it is necessary to maintain the soil temperature control and weed suppression effects during this period, and to improve the sheet durability. It costs. After harvesting the crop, it is preferable to lower the strength by plowing the soil and burying it in the soil.
The sheet-like molded product or agricultural sheet of the present invention is suitable for this. Hereinafter, a specific example will be described.

[0026]

EXAMPLES (Reference Example 1) Polycaprolactone pellets (melt index: 2.57 g / 10 min) were heated to a melting point or higher, then cooled to 50 ° C., and while in an amorphous state, γ-ray was irradiated at 60 kGy as radiation. Upon irradiation with 160 kGy, the melt index of each of the treated pellets obtained was 0.05 g / 10 min (gel fraction 60% described later).
And 0.03 g / 10 min (80% gel fraction). The untreated pellets and the treated pellets were placed in an urban sewage sludge environment at 25 ° C. and 4 ° C. according to JIS K6950.
They were subjected to a weekly biodegradability test. As a result, the decomposition rate of the non-irradiated product was 72.1%, whereas that of the irradiated product was 86.2% and 77.2%, respectively. Further, the irradiated product was formed into a sheet by a hot press at 200 ° C., and a biodegradability test was similarly performed on the pulverized sample. As a result, the decomposition rates were 87.0% and 87.8%, respectively. The same test results were obtained by changing the irradiation type from gamma rays to electron beams.

Reference Example 2 The polycaprolactone used in Reference Example 1 was irradiated at normal temperature with an electron beam irradiation amount of 15 kGy. Processed pellets (melt index is 1.0
g / 10 min, gel fraction 0.2%) was extruded with an extruder (resin temperature 150 ° C.) provided with a 40 mmφ T-die to obtain a sheet having a thickness of about 270 μm. The obtained sheet was subjected to a tear test, an impact strength test according to JIS K7211 and a tensile test according to JIS K6782 at room temperature, and compared with the test results of unirradiated products similarly formed into sheets. As a result, the tensile strength (MD: longitudinal direction) was 260, 280 kgf in the order of the unirradiated product and the irradiated product.
・ Cm, the lateral direction (TD) is 210, 230kgf ・ c
m, tensile elongation (MD) 1130, 1240%, TD
Is 1130, 1160%, the tear strength (MD) is 160,
270 gf, the TD improved to 190 and 450 gf, and the impact strength test improved to 23.8 and 25.2 kgf · cm, respectively.

Example 1 Polycaprolactone pellets (melt index 2.57 g / 10 min) were irradiated at room temperature with an electron beam irradiation of 15 kGy. Prepare a 5% toluene solution of treated pellets (melt index: 1.0 g / 10 min, gel fraction 0.2% described below), and prepare 24 g
/ M ² of paper. After the application, it was dried with hot air, and when the solvent was volatilized and the mass became constant, an impregnated paper having a resin application amount of 1.9 g / m ² was obtained. This was laid on a ridge of an outdoor field using a mulcher, and subjected to a test for degradability and durability. In the evaluation, the durability was evaluated by the appearance of the sheet to determine whether the sheet was torn. The gel fraction was 24 in acetone.
It is the ratio of the insoluble matter immersed for a time and represents the degree of cross-linking, which is determined by the following equation. Gel fraction _{(%) = (W 2 /} W 1) × 100 ( wherein, W ₁ represents the dry weight of the PCL before immersion, W ₂
Represents the dry weight of the insoluble matter after immersion. )

Example 2 The concentration of the caprolactone resin used in Example 1 was set to 7%, and an impregnated paper having a resin application amount of 2.9 g / m ² was obtained in the same manner. The evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 1) An impregnated paper was obtained in the same manner as in Example 1 except that the caprolactone resin not subjected to the irradiation treatment used in Example 1 was used. Evaluation was performed in Example 1.
The same was done. The results are shown in Table 1.

(Comparative Example 2) The same evaluation as in Example 1 was performed using only paper without using the biodegradable resin caprolactone resin. The results are shown in Table 1.

Comparative Example 3 A conventional polyethylene (low-density polyethylene) multi-sheet (0.1 mm thick)
The same evaluation as in Example 1 was performed. The results are shown in Table 1.

[0033]

[Table 1]

[0034]

The sheet according to the present invention has a high strength for a long period of time as seen particularly when used as an agricultural sheet, but has a biodegradability in terms of the possibility of plowing into soil. It was found to show sufficient biodegradability.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroshi Mitomo 1-5-1, Tenjin-cho, Kiryu-shi, Gunma Gunma University Faculty of Engineering (72) Inventor Dharmawan Dalwis 1-5-1, Tenjin-cho, Kiryu-shi, Gunma Gunma University Faculty of Engineering (72) Inventor Tadashi Murakami 1-323 Shinmatsudo Minami, Matsudo City, Chiba Prefecture

Claims (8)

[Claims] 1. A sheet composition comprising, as a constituent, a lactone resin which has been subjected to a radiation irradiation treatment. 2. The sheet composition according to claim 1, wherein the lactone resin is poly-ε-caprolactone. 3. A sheet-like molded article formed by impregnating paper with the non-aqueous solution or emulsion slurry of the lactone resin according to claim 1 or 2 and forming the sheet. 4. A sheet-like molded product obtained by mixing the lactone resin according to claim 1 together with paper fibers. 5. A sheet-like molded product obtained by laminating a film comprising the lactone resin according to claim 1 or 2. 6. A sheet-like molded product comprising a mixture of a powdery and / or fibrous material and a powdery and / or fibrous material other than the lactone resin, according to claim 1 or 2. . 7. The lactone resin according to claim 1 or 2,
A sheet-like molded product which is coated on a sheet-like material formed from a powdery and / or fibrous material. 8. An agricultural sheet comprising an impregnated paper impregnated with the lactone resin according to claim 1 or 2.