JP2018068229A - Protective material for trees - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a biodegradable protective material for trees that has excellent workability in winding and re-winding and also has excellent visibility and strength.SOLUTION: A protective material for trees is wound around a tree to protect it from peeling damage. The protective material contains a resin composition mainly composed of a polylactic acid resin (A) and has a light transmittance of 40% or less in wavelengths of 240 nm or more and 800 nm or less.SELECTED DRAWING: None

Description

  The present invention relates to a protective material for trees, and for example, relates to a protective material for trees that is prevented from being peeled by being wound around the tree.

  In recent years, there has been an increase in the skin damage caused by various bark and beasts such as bears and deers that are peeled off and eaten. Trees that have suffered bark damage die without being regenerated, causing serious damage to forestry managers and the environment. Therefore, protective measures against tree bark damage have been taken.

  For skin damage, protective measures have been proposed to prevent birds and animals from approaching trees using repellents and explosive sounds. However, these protective measures are temporary in effect, and in addition to the considerable costs and labor (work) involved in the implementation, the adverse effects on the natural environment due to the occurrence of dust etc. are pointed out. ing. In addition, although protective measures have been taken by killing birds and beasts that cause skin damage, it is not preferable from the viewpoint of protecting wild animals.

  In addition, a protective measure has been proposed in which an obstacle such as a low-cost protective tape that prevents the contact of birds and beasts on the bark is wrapped around the tree as a protective material for the tree against damage due to peeling. In this protection measure, a tape using a biodegradable resin has attracted attention as a protective material for trees because it does not need to be recovered after use and does not harm the natural environment. As the protective material for trees using such a biodegradable resin, a band-shaped animal damage prevention tool using a biodegradable plastic (for example, see Patent Document 1), a biodegradable synthetic resin material was used. Protective tape for bark of net-like bark using a net-like structure and string-like fastening body (for example, see Patent Document 2), a tree root protector for winding a tape using a biodegradable resin material around the root part of the tree, etc. Has been proposed (see, for example, Patent Document 3).

JP2013-5731A Japanese Patent Laying-Open No. 2015-173654 JP 2012-19716 A

  However, in the conventional protective material for trees, it is not always possible to efficiently wrap around the change in the thickness and the protection area of each tree, and it takes time for the winding and rewinding work, and the workability is not sufficient. . Moreover, the conventional protective material for trees is not necessarily sufficient in strength, and the protective material may be torn during winding and rewinding operations. Furthermore, in the conventional protective material for trees, the visibility is not always sufficient, and the protective material wound around the tree may not be sufficiently visible.

  An object of the present invention is to provide a biodegradable protective material for trees that is excellent in workability during winding and rewinding, and has excellent visibility and strength.

  As a result of intensive studies in view of the above circumstances, the inventors of the present invention contain a resin composition containing a biodegradable polylactic acid resin (A) as a main component and have a light transmittance of not more than a predetermined value. The present inventors have found that the above problems can be solved by a protective material, and have completed the present invention.

  The protective material for trees of the present invention is a protective material for trees that prevents the peeling of trees from being wound by being wound around the tree, and contains a resin composition mainly composed of a polylactic acid resin (A), and has a wavelength. The light transmittance in the range of 240 nm or more and 800 nm or less is 40% or less.

  According to the protective material for trees of the present invention, since the resin composition containing the polylactic acid resin (A) as a main component is contained, not only excellent biodegradability is obtained, but also the slipping property is in an appropriate range. Workability at the time of winding and rewinding is improved and sufficient strength is obtained. And since light transmittance is 40% or less, the visibility at the time of winding the protective material for trees around a tree improves. Therefore, it is possible to realize a biodegradable protective material for trees that is excellent in workability during winding and rewinding and has excellent visibility and strength.

  In the protective material for trees of this invention, it is preferable that the said resin composition contains a light-scattering agent (B) further.

  In the protective material for trees of this invention, it is preferable that the said light-scattering agent (B) contains an inorganic filler (B-1).

  In the protective material for trees of this invention, it is preferable that the compounding quantity of the inorganic filler (B-1) in the said resin composition is 0.1 to 30 mass%.

  In the protective material for trees of the present invention, the light scattering agent (B) is an incompatible resin (B-) that is incompatible with the inorganic filler (B-1) and the polylactic acid resin (A). 2) is preferably contained.

  In the protective material for trees of this invention, the compounding quantity of the said inorganic filler (B-1) is 0.1 to 30 mass% with respect to the total mass of the said resin composition, It is preferable that the compounding quantity of incompatible resin (B-2) is 5 mass% or more and 18 mass% or less.

  In the protective material for trees of this invention, it is preferable that the refractive index of the said inorganic filler (B-1) is 1.50 or more.

  In the protective material for trees of this invention, it is preferable that the said light-scattering agent (B) contains incompatible resin (B-2) incompatible with the said polylactic acid-type resin (A).

  In the protective material for trees of this invention, it is preferable that the compounding quantity of the said incompatible resin (B-2) in the said resin composition is 5 to 18 mass%.

  In the protective material for trees of the present invention, the molecular weight retention of the weight average molecular weight after one week is preferably 45% or more under the conditions of 70 ° C. and 70% RH.

  In the protective material for trees of this invention, it is preferable that it is a stretched film.

  ADVANTAGE OF THE INVENTION According to this invention, while being excellent in workability | operativity at the time of winding and rewinding, the biodegradable protective material for trees excellent in visibility and intensity | strength is realizable.

  Hereinafter, an embodiment of the present invention will be described in detail. In addition, this invention is not limited to the following embodiment, It can implement by changing suitably. In the following embodiments, when expressed as “X to Y” (X and Y are arbitrary numbers), it means “X or more and Y or less” unless otherwise specified, and “preferably larger than X”. And “preferably less than Y”. In addition, when expressed as “more than X” (X is an arbitrary number), unless otherwise specified, the meaning of “preferably greater than X” is included, and expressed as “Y or less” (Y is an arbitrary number). In the case, unless otherwise specified, the meaning of “preferably smaller than Y” is included.

<Protective material for trees>
The protective material for trees according to the present embodiment is a protective material for trees that prevents tree peeling damage by wrapping around the tree, and a resin composition containing a polylactic acid resin (A) as a main component. And the light transmittance in a wavelength range of 240 nm to 800 nm is 40% or less.

  According to this protective material for trees, since the resin composition containing the polylactic acid resin (A) as a main component is contained, not only excellent biodegradability is obtained, but also the slipping property is in an appropriate range. In addition, workability during rewinding is improved and sufficient strength is obtained. And since light transmittance is 40% or less, the visibility at the time of winding the protective material for trees around a tree improves. Therefore, it is possible to realize a biodegradable protective material for trees that is excellent in workability during winding and rewinding and has excellent visibility and strength.

  The protective material for trees according to the present embodiment is not limited in thickness, length, and width as long as it can be wound around a tree. Alternatively, it may be in the form of a sheet. In general, a “sheet” refers to a product that is thin by definition according to JIS and has a small thickness instead of length and width. In general, "film" refers to a thin flat product that is extremely small compared to its length and width and whose maximum thickness is arbitrarily limited, and is usually supplied in the form of a roll. (Japanese Industrial Standard JIS K-6900). For example, in the narrow sense, the thickness of 100 μm or more may be referred to as a sheet, and the thickness of less than 100 μm may be referred to as a film. However, since the boundary between the sheet and the film is not clear and it is not necessary to distinguish the two in terms of words, in the present embodiment, even when the term “film” is used, the term “sheet” is included and the term “sheet” is used. But “film” is included. In the present embodiment, the refractive index of the protective material for trees is, for example, a value measured with an Abbe refractometer in accordance with method A of JIS K-7142.

  Moreover, the protective material for trees may consist of a single layer, or may be a two-layer laminate in which two protective materials for trees are laminated. Furthermore, the protective material for trees may be a two-layer laminate with another layer other than the protective material for trees (hereinafter, also simply referred to as “other layers”), and between the pair of protective materials for trees. Alternatively, a three-layer laminate in which other layers are provided as intermediate layers may be used, or a three-layer laminate in which a tree protective material is laminated between a pair of other layers. Thus, rigidity, mechanical properties, concealing properties, heat resistance, and the like can be improved by forming a laminate in which the protective material for trees and other layers are laminated. As the other layer, from the viewpoint of maintaining the biodegradability of the protective material for trees, a layer mainly composed of a biodegradable resin is preferable, and a layer mainly composed of a polylactic acid resin (A) is more preferable. Hereinafter, various components of the protective material for trees will be described in detail.

<Polylactic acid resin (A)>
The resin composition of the protective material for trees has a polylactic acid resin (A) as a main component. The polylactic acid resin (A) is not particularly limited as long as it contains polylactic acid (PLA). As the polylactic acid resin (A), poly-L-lactic acid (PLLA) whose structural unit is L-lactic acid may be used, or poly-D-lactic acid (PDLA) whose structural unit is D-lactic acid. Alternatively, poly-DL-lactic acid (PDLLA) whose structural units are L lactic acid and D lactic acid may be used, and at least two of these poly-L lactic acid, poly-D lactic acid and poly-DL-lactic acid are mixed. The mixed resin may be used. Among these, as the polylactic acid resin (A), those having a relatively high proportion of L-lactic acid contained in the structural unit with respect to D-lactic acid are preferable from the viewpoint of excellent heat resistance.

  The polylactic acid-based resin (A) adjusts the heat of crystal fusion (ΔHm) to a desired range by changing the ratio (molar ratio) between L-lactic acid (L-form) and D-lactic acid (D-form). be able to. The polylactic acid-based resin (A) preferably has a crystal melting heat amount (ΔHm) of 30 J / g or more, and 35 J / g or more from the viewpoint of sufficiently obtaining strength when wound on a tree. It is more preferable that it is 40 J / g or more. In addition, the polylactic acid resin (A) has a higher strength as the heat of crystal fusion (ΔHm) is higher, and can sufficiently exhibit performance. The amount of heat of crystal melting (ΔHm) is preferably 60 J / g or less, for example, from the viewpoint that the degree of crystallinity becomes moderately low and the stretchability of the resin composition becomes good. In the present embodiment, the heat of crystal melting (ΔHm) of the polylactic acid resin (A) is measured in accordance with JIS K-7121. The amount of heat of crystal melting (ΔHm) can be measured using, for example, a differential scanning calorimeter (model number “DSC-7”, manufactured by PerkinElmer).

  From the viewpoint of obtaining sufficient heat resistance, the polylactic acid resin (A) has a molar ratio of L-lactic acid (L form) to D-lactic acid (D form) of L form / D form = 90/10 to 100. / 0, preferably L-form / D-form = 95/5 to 99.5 / 0.5, and more preferably L-form / D-form = 97/3 to 99/1. .

  The polylactic acid-based resin (A) has a ratio (molar ratio) between L-lactic acid (L-form) and D-lactic acid (D-form) of L-form / D-form = 100/0 to 97/3. Lactic acid-based resin (A-1), L-form / D-form = 0 / 100-3 / 97 is polylactic acid-based resin (A-2), L-form / D-form = 97 / 3-85 / 15 is poly When the lactic acid resin (A-3) is used and 3/97 to 15/85 is the polylactic acid resin (A-4), the heat of crystal melting (ΔHm) of the polylactic acid resin (A) is 30 J / g or more. From the viewpoint that can be made, polylactic acid resin (A-1) or (A-2) / polylactic acid resin (A-3) or (A-4) = 100/0 to 50/50 by mass ratio Are preferably mixed at a ratio of 100/0 to 90/10, more preferably at a ratio of 100/0 to 95/5. A further preferred.

  Moreover, as polylactic acid-type resin (A), at least 1 sort (s) of various polylactic acid-type resin (A) mentioned above, diols, such as alpha-hydroxycarboxylic acid and aliphatic diol, and dicarboxylic acids, such as aliphatic dicarboxylic acid, Alternatively, a copolymer obtained by copolymerizing with may be used.

  α-hydroxycarboxylic acid includes L-lactic acid or optical isomers of D-lactic acid (D-lactic acid for L-lactic acid, L-lactic acid for D-lactic acid), glycolic acid, 3-hydroxybutyric acid Bifunctional fats such as 4-hydroxybutyric acid, 2-hydroxy-n-butyric acid, 2-hydroxy-3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-methyllactic acid, and 2-hydroxycaproic acid And lactones such as group hydroxycarboxylic acids, caprolactone, butyrolactone, and valerolactone.

  Examples of the diol include aliphatic diols such as ethylene glycol, 1,4-butanediol, and 1,4-cyclohexanedimethanol. Examples of the dicarboxylic acid include aliphatic dicarboxylic acids such as succinic acid, adipic acid, suberic acid, sebacic acid, and dodecanedioic acid.

  The polylactic acid resin (A) is obtained by a condensation polymerization method, a ring-opening polymerization method, and other known polymerization methods. In the condensation polymerization method, L-lactic acid or D-lactic acid, or a mixture of L-lactic acid and D-lactic acid is directly subjected to dehydration condensation polymerization to obtain a polylactic acid resin (A) having an arbitrary composition. In the ring-opening polymerization method, polylactic acid-based resin (A) is obtained by ring-opening polymerization of lactide, which is a cyclic dimer of lactic acid, in the presence of a catalyst using a polymerization regulator as necessary. can get. As the lactide, L-lactide, which is a dimer of L-lactic acid, or D-lactide, which is a dimer of D-lactic acid, may be used, which is composed of L-lactic acid and D-lactic acid. DL-lactide may be used. In the ring-opening polymerization, a polylactic acid resin (A) having a desired composition and crystallinity is obtained by mixing and polymerizing the above-described lactide as necessary.

  The polylactic acid-based resin (A) is a non-aliphatic dicarboxylic acid such as terephthalic acid and an ethylene oxide adduct of bisphenol A and the like from the viewpoint of further improving the heat resistance as necessary within the range where the effects of the present invention are exhibited. A non-aliphatic diol may be contained as a copolymerization component, and a chain extender such as a diisocyanate compound, an epoxy compound and an acid anhydride may be contained as a copolymerization component. In this case, the polylactic acid resin (A) preferably has a polylactic acid component content of 90% by mass or more and less than 100% by mass.

  The weight average molecular weight of the polylactic acid resin (A) is preferably from 50,000 to 400,000, and more preferably from 100,000 to 250,000. If the weight average molecular weight is 50,000 or more, the polylactic acid-based resin (A) has sufficient slipperiness, strength, and biodegradability, and if it is 400,000 or less, the melt viscosity is suitably lowered and good. Moldability can be obtained. In the present embodiment, the weight average molecular weight is a value measured using gel permeation chromatography (GPC).

  As the polylactic acid resin (A), various commercially available products (for example, trade name “Nature Works” (registered trademark), manufactured by Nature Works) may be used.

  The content of the polylactic acid resin (A) in the protective material for trees is 70 with respect to the total mass of the resin composition from the viewpoints of workability, visibility, strength, and biodegradability during winding and rewinding. % By mass or more and 99.9% by mass or less are preferable, 75% by mass or more and 99% by mass or less are more preferable, and 80% by mass or more and 98% by mass or less are more preferable.

<Light scattering agent (B)>
It is preferable that the protective material for trees further contains a light scattering agent (B). By containing this light scattering agent (B), the light is dispersed in the protective material for trees and the visibility is further improved, and the slipperiness is further improved by the light scattering agent (B) dispersed in the resin. Further improve. As a light-scattering agent (B), various light-scattering agents can be used in the range with the effect of this invention. As the light scattering agent (B), for example, an incompatible resin (B-2) that is incompatible with the inorganic filler (B-1) and the polylactic acid resin is used. Hereinafter, the configuration of each light scattering agent (B) will be described in detail.

(First embodiment)
In the first embodiment, the light scattering agent (B) contains an inorganic filler (B-1). Thus, by containing an inorganic filler (B-1) as a light-scattering agent (B), the visibility and slipperiness of a protective material for trees are further improved. As the inorganic filler (B-1), for example, various inorganic fillers that mainly improve slipperiness and various pigments that mainly impart visibility are used.

  Examples of inorganic fillers include silica, talc, kaolin, alumina (aluminum oxide), calcium carbonate, bentonite, mica, sericite, glass flakes, beads, silica balloon, shirasu balloon, magnesium hydroxide, aluminum hydroxide, and trioxide. Antimony, barium sulfate, titanium oxide (titanium dioxide), lead titanate, potassium titanate, zircon oxide, zinc sulfide, antimony oxide, zinc oxide, zinc borate, hydrous calcium borate, magnesia, wollastonite, zonotrite, sepiolite Whisker, glass fiber, glass flake, metal powder, and the like can be used.

  Examples of the pigment include white pigments such as titanium oxide and barium sulfate, and colored pigments such as ferric oxide, chromium oxide, carbon black, and ultramarine. Among these, white pigments are preferable from the viewpoint of visibility of the protective material for trees, and titanium oxide is more preferable from the viewpoints of visibility and slipperiness of the protective material for trees. As the titanium oxide, any of rutile type titanium oxide and anatase type titanium oxide may be used, and anatase type titanium oxide is preferable from the viewpoint of visibility and slipperiness of the protective material for trees.

  As an inorganic filler (B-1), the inorganic filler and pigment mentioned above may be used independently, and 2 or more types may be used together. As the inorganic filler (B-1), when used alone, it is preferable to improve both slipperiness and visibility. When two or more kinds are used in combination, both slipperiness and visibility are achieved. What improves may be mixed, and what mainly improves slipperiness and what mainly improves visibility may be used together.

  The inorganic filler (B-1) preferably has a refractive index of 1.50 or more, and more preferably 1.55 or more, from the viewpoint of the visibility of the protective material for trees. The inorganic filler (B-1) contains a refractive index of 1.50 or more, so that the difference in refractive index is larger than that of the polylactic acid resin (A) having a refractive index of 1.45. Even if the amount is reduced, excellent visibility can be obtained. There is no restriction | limiting in particular in the upper limit of a refractive index, For example, it is 5.00 or less. In this Embodiment, the refractive index of an inorganic filler (B-1) is the value measured with the Abbe refractometer based on B method of JISK-7142, for example.

  As the inorganic filler (B-1), talc, kaolin, alumina (aluminum oxide), barium sulfate, magnesia (magnesium oxide), zinc oxide, zinc sulfide, zircon oxide from the viewpoint that the refractive index is 1.50 or more. In addition, potassium titanate, lead titanate, titanium oxide, and various pigments are preferable, and talc is more preferable from the viewpoint of the balance between slipperiness and visibility and cost. Further, from the viewpoint of having a large refractive index and obtaining visibility effectively, a white pigment is preferable, and among the white pigments, titanium oxide is more preferable.

  The inorganic filler (B-1) preferably has an average particle size of 0.1 μm or more and 5 μm or less, from 0.15 μm to 3 μm, from the viewpoint of the strength, elongation and slipperiness of the protective material for trees. More preferably. If the average particle diameter of the inorganic filler (B-1) is 5 μm or less, the inorganic filler (B-1) in the resin film is less likely to be a starting point of breakage, and the strength and elongation are improved. Moreover, if an average particle diameter is 0.1 micrometer or more, an inorganic filler (B-1) will not aggregate easily, it will be hard to produce a dispersion | distribution defect, and the slipperiness | lubricity of the protective material for trees will improve. In this Embodiment, the average particle diameter of an inorganic filler (B-1) is the value of D50 measured by a laser diffraction method.

  As for the compounding quantity of the inorganic filler (B-1) of the resin composition in 1st Embodiment, 0.1 to 30 mass% is preferable with respect to the total mass of a resin composition. If the blending amount of the inorganic filler (B-1) is 0.1% by mass or more, sufficient visibility is obtained, and if it is 30% by mass or less, the stretchability of the resin composition is improved. The mechanical strength of the protective material for trees is improved. The blending amount of the inorganic filler (B-1) is more preferably 1% by mass or more and 25% by mass or less, further preferably 2% by mass or more and 20% by mass or more, and 3% by mass or more with respect to the total mass of the resin composition. 15 mass% or less is still more preferable.

  The compounding quantity of the inorganic filler (B-1) of the resin composition in 1st Embodiment is 0.1 mass part or more and 42.9 mass parts or less with respect to 100 mass parts of polylactic acid-type resin (A). Is preferred. When the blending amount of the inorganic filler (B-1) is 0.1 parts by mass or more with respect to 100 parts by mass of the polylactic acid resin (A), sufficient visibility is obtained, and 42.9 masses. If it is below a part, the extensibility of a resin composition will improve and the mechanical strength of the protective material for trees will improve. The blending amount of the inorganic filler (B-1) is preferably 1 part by mass or more and 33.3 parts by mass or less, and more preferably 2 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the polylactic acid resin (A). More preferably, it is 3 parts by mass or more and 17.6 parts by mass or less.

(Second Embodiment)
In the second embodiment, the light scattering agent (B) contains an incompatible resin (B-2). Thus, when the light-scattering agent (B) contains the incompatible resin (B-2), the visibility and slipperiness of the protective material for trees are further improved.

  According to the second embodiment, since the polylactic acid resin (A) forms a matrix and the incompatible resin (B-2) forms a dispersion domain, a sea-island structure is formed as the entire resin composition. The The resin composition is formed into a sheet shape, and further stretched in at least one direction, thereby peeling at the interface between the matrix polylactic acid resin (A) and the dispersion domain incompatible resin (B-2). And voids are formed, so that visibility can be imparted by the difference in refractive index.

  The incompatible resin (B-2) is not particularly limited as long as it is incompatible with the polylactic acid resin (A). Here, incompatible is a state in which a dispersed domain in which phases are separated at a molecular level is formed when an incompatible resin (B-2) is mixed with a polylactic acid resin (A). Say. The incompatible resin (B-2) is not limited as long as the phase is separated at the molecular level when mixed with the polylactic acid resin (A), and is partially compatible with the polylactic acid resin (A). It may be melted. From the standpoint of efficiently forming the sea-island structure as a whole film, the polylactic acid resin (A) forms a matrix, the resin (C) forms a dispersion domain, and the phases are separated without mixing at all. It is preferable.

  As the incompatible resin (B-2), a non-biodegradable resin or a biodegradable resin may be used. Examples of non-biodegradable resins include polystyrene resins, amorphous polyester resins, amorphous polyamide resins, and polycarbonate resins. Among these, as the non-biodegradable resin, a polystyrene-based resin is preferable from the viewpoint that a better concealing effect can be obtained and heat resistance can be imparted even with a small addition amount.

  Examples of the biodegradable resin include polybutylene adipate terephthalate, which is a copolymer of polybutylene adipate and terephthalate, and polybutylene succinate, which is a condensation polymer of succinic acid and 1,4 butanediol. Among these, polybutylene adipate terephthalate is preferable as the biodegradable resin from the viewpoint of excellent biodegradability. As the biodegradable resin, for example, a commercially available product of polybutylene adipate terephthalate (trade name “Ecoflex”, manufactured by BASF), or a commercially available product of polybutylene succinate (trade name “BioPBS”, manufactured by Mitsubishi Chemical Corporation) is used. May be.

  The incompatible resin (B-2) preferably contains a biodegradable resin in the same manner as the polylactic acid resin (A) from the viewpoint of improving the biodegradability of the protective material for trees. The content of the biodegradable resin in the incompatible resin (B-2) is preferably 50% by mass or more, more preferably 75% by mass or more, based on the total mass of the incompatible resin (B-2). 90 mass% or more is still more preferable, and it is especially preferable that it is 100 mass%.

  As the incompatible resin (B-2), those having a storage elastic modulus (E ′) at 80 ° C. of 700 MPa or more and 5000 MPa or less are preferable. If the storage modulus (E ′) is 700 MPa or more, the incompatible resin (B-2) is a polylactic acid resin (A) when the resin composition is stretched. If the storage elastic modulus (E ′) is 5000 MPa or less, the stretchability when the resin composition is stretched to form a film may be inhibited. And can be stretched without breaking. The storage elastic modulus (E ′) at 80 ° C. of the incompatible resin (B-2) is more preferably 1000 MPa or more, further preferably 1500 MPa or more, more preferably 4000 MPa or less, and still more preferably 3000 MPa or less. The storage elastic modulus (E ′) can be measured by using, for example, a viscoelastic spectrometer (model number “DVA-200”, manufactured by IT Measurement Co., Ltd.).

  The incompatible resin (B-2) is a polylactic acid resin (A) in an unstretched state when a mixture of the polylactic acid resin (A) and the incompatible resin (B-2) is used as an extruded sheet. ) Is preferably in a state where the incompatible resin (B-2) forms a dispersion domain having an equivalent circle diameter of 0.1 μm or more on average. The equivalent circle diameter of the incompatible resin (B-2) in the polylactic acid resin (A) can be measured by various optical devices such as an electron microscope.

  As for the compounding quantity of the incompatible resin (B-2) of the resin composition in 2nd Embodiment, 5 mass% or more and 18 mass% or less are preferable with respect to the total mass of a resin composition. If the blending amount of the incompatible resin (B-2) is 5% by mass or more, not only sufficient visibility is obtained, but also the trees formed by the pores formed by the incompatible resin (B-2). The surface of the protective material has unevenness and can impart a good balance of slipperiness, and if it is 18% by mass or less, it prevents the generation of excessive pores when the resin composition is stretched to prevent thickness fluctuations and physical properties. While a fall can be prevented, sufficient biodegradability is obtained even when a non-biodegradable resin is used as the incompatible resin (B-2). 6 mass% or more and 15 mass% or less are more preferable with respect to the total mass of a resin composition, and, as for the compounding quantity of incompatible resin (B-2), 7 mass% or more and 13 mass% are still more preferable.

  The compounding amount of the incompatible resin (B-2) of the resin composition in the second embodiment is 5.3 parts by mass or more and 22 parts by mass or less with respect to 100 parts by mass of the polylactic acid resin (A). preferable. If the blending amount of the incompatible resin (B-2) is 5.3 parts by mass or more with respect to 100 parts by mass of the polylactic acid resin (A), sufficient visibility is obtained, and 22 parts by mass is obtained. If it is below, the stretchability of the resin composition is improved and the mechanical strength of the protective material for trees is improved. The blending amount of the incompatible resin (B-2) is more preferably 6.4 parts by mass or more and 17.6 parts by mass or less, and 7.5 parts by mass or more with respect to 100 parts by mass of the polylactic acid resin (A). 14.9 parts by mass or less is more preferable.

(Third embodiment)
In 3rd Embodiment, an inorganic filler (B-1) and incompatible resin (B-2) are used together as a light-scattering agent (B). Thereby, while visibility can be improved efficiently by an inorganic filler (B-1), slipperiness improves efficiently by an incompatible resin (B-2). As an inorganic filler (B-1), the same thing as 1st Embodiment mentioned above can be used. Further, as the incompatible resin (B-2), the same resin as in the second embodiment described above can be used.

  The blending amounts of the inorganic filler (B-1) and the incompatible resin (B-2) in the resin composition in the third embodiment are the viewpoint that sufficient visibility is obtained, the stretchability of the resin composition, and From the viewpoint of improving the mechanical strength of the protective material for trees, the inorganic filler (B-1) is 0.1% by mass to 30% by mass with respect to the total mass of the resin composition, and is an incompatible resin. (B-2) is preferably 5% by mass or more and 18% by mass or less, the inorganic filler (B-1) is 1% by mass or more and 25% by mass or less, and the incompatible resin (B-2) is 6% by mass. It is more preferably 15% by mass or less, more preferably 2% by mass to 20% by mass of the inorganic filler (B-1), and further preferably 7% by mass to 13% by mass of the incompatible resin (B-2). .

  The blending amounts of the inorganic filler (B-1) and the incompatible resin (B-2) in the resin composition in the third embodiment are the viewpoint that sufficient visibility is obtained, the stretchability of the resin composition, and From the viewpoint of improving the mechanical strength of the protective material for trees, the inorganic filler (B-1) is 0.1 to 42.9 parts by mass with respect to 100 parts by mass of the polylactic acid resin (A). The incompatible resin (B-2) is preferably 5.3 parts by mass or more and 22 parts by mass or less, and the inorganic filler (B-1) is 1 part by mass or more and 33.3 parts by mass or less and is incompatible. The resin (B-2) is more preferably from 6.4 parts by weight to 17.6 parts by weight, and the inorganic filler (B-1) is from 2 parts by weight to 30 parts by weight, and the incompatible resin (B- 2) is more preferably 7.5 parts by weight or more and 14.9 parts by weight or less.

  In consideration of the above first to third embodiments, the blending amount of the light scattering agent (B) is preferably 5% by mass or more and 18% by mass or less with respect to the total mass of the resin composition. 6 mass% or more and 15 mass% or less is more preferable, and 7 mass% or more and 12.5 mass% or less are still more preferable. The blending amount of the light scattering agent (B) is preferably 5.3 parts by mass or more and 22 parts by mass or less, and 6.4 parts by mass or more and 17.6 parts by mass with respect to 100 parts by mass of the polylactic acid resin (A). Part or less, more preferably 7.5 parts by mass or more and 15.7 parts by mass or less.

(Other ingredients)
The resin composition may be added with other resins and modifiers having compatibility with the polylactic acid resin (A) within the range where the effects of the present invention are exhibited. As the resin and the modifier, a non-biodegradable one may be used, but it is preferable to use a biodegradable resin and a modifier. Moreover, the resin composition may mix | blend the additive mix | blended with a general resin composition within the range with the effect of this invention. Examples of the additive include an ultraviolet absorber, a light stabilizer, an antioxidant, a plasticizer, a nucleating agent, a lubricant, a pigment, and a dye. Moreover, when using as a laminated body which laminated | stacked the protective material for trees with the other layer, you may add the said additive etc. also to the resin composition used for another layer.

<Method for producing protective material for trees>
Next, the manufacturing method of the protective material for trees which concerns on the said embodiment is demonstrated. The protective material for trees can be produced by a conventionally known method. The protective material for trees, for example, after mixing and kneading the polylactic acid resin (A), the light scattering agent (B) and other resins and additives so as to have a mixing ratio of a desired blending amount, It can manufacture by extruding with a single screw extruder or a twin screw extruder.

  Moreover, when manufacturing the protective material for trees as a laminated body with another layer, the other layer has a mixing ratio in which the polylactic acid resin (A) and other resins and additives are in a predetermined blending amount. After being mixed and kneaded so as to become, it can be produced by extruding with a single screw extruder or a twin screw extruder. And a laminated body can be manufactured by laminating | stacking the extruded tree | wood protective material and the other extruded layer by coextrusion, extrusion lamination, a heat | fever lamination, dry lamination, etc. In the case of co-extrusion, a laminate is manufactured by joining a protective material for trees and other layers using a feed block type or multi-manifold type die using a plurality of extruders. be able to.

  The tree protective material is preferably a stretched film in which the resin composition is stretched in at least one direction. Here, the stretched film is a stretched film stretched in at least one direction. The resin composition may be uniaxially stretched or biaxially stretched. Examples of biaxial stretching include sequential stretching and simultaneous biaxial stretching. The resin composition is preferably a biaxially stretched film. Thereby, the balance of mechanical properties becomes good, and physical properties such as tear strength of the stretched film are improved.

  When biaxial stretching is performed, stretching in the flow direction (longitudinal direction: MD direction) of the resin composition and the vertical direction (transverse direction: TD direction) perpendicular to the flow direction may be performed sequentially or simultaneously. . Among these, from the viewpoint of mechanical properties of the stretched film, sequential biaxial stretching in which the film is stretched in the longitudinal direction and then stretched in the transverse direction is preferable. The stretching of the resin composition may be any of a roll method, a tenter method, and a tubular method.

  As extending | stretching temperature of a resin composition, 65 to 95 degreeC is preferable, 67 to 90 degreeC is more preferable, 70 to 87 degreeC is still more preferable. If the stretching temperature is 65 ° C. or higher, the generation of pores during stretching can be suppressed, so that the decrease in rigidity of the stretched film due to the decrease in density can be prevented. The crystallization of the resin (A) is prevented and sufficient stretching is possible, and the stretched film is not broken.

  The draw ratio is preferably 2 times or more, more preferably 3 times or more, further preferably 4 times or more, more preferably 16 times or less, still more preferably 12 times or less, and still more preferably 9 times or less. If the draw ratio is 2 times or more, there will be no unevenness in the thickness distribution at the time of stretching, the rigidity of the stretched film can be prevented from decreasing, and the pores in the stretched film can be suppressed at the time of stretching to prevent the density from decreasing. And a decrease in the rigidity of the stretched film can be prevented.

  The stretched film is preferably subjected to heat treatment (heat setting) in a state where the stretched film is held after the stretching treatment in order to suppress thermal shrinkage. Usually, in the roll method, heat treatment is performed by contacting the heated roll after stretching, and in the tenter method, heat treatment is performed in a state where the stretched film is held by a clip. The heat treatment temperature varies depending on the mixing ratio and type of the resin used, but is preferably in the range of 100 ° C. or more and 150 ° C. or less. Such heat treatment can impart superior heat resistance and mechanical properties to the stretched film.

  The thickness of the protective material for trees is not particularly limited, and is preferably thinner from the viewpoint of raw material costs and the like. The thickness of the protective material for trees is preferably 0.005 mm or more and 0.1 mm or less, more preferably 0.01 mm or more and 0.05 mm or less, and further preferably 0.01 mm or more and 0.03 mm or less. If the protective material for trees is 0.005 mm or more, the stretched film can be easily formed and the handleability is good, and if it is 0.1 mm or less, the stretchability of the stretched film is good.

  As for the protective material for trees, the static friction coefficient between the protective materials for trees measured according to JIS K-7125 is 0.8 or less from the viewpoint of improving the slidability of the protective material for trees and improving workability. Preferably, it is 0.7 or less, and the lower limit is not particularly limited, but winding of the protective material for trees in the production process and the processing process while ensuring appropriate friction between the protective materials for trees From the viewpoint of improving takeability, it is preferably 0.3 or more.

  The protective material for trees has a through-hole strength of preferably 50 N / mm or more, and more preferably 100 N / mm or more, from the viewpoint of efficiently preventing the peeling of the trees from birds and beasts when wrapping around the tree. More preferably, it is 300 N / mm or more. Although there is no restriction | limiting in particular in an upper limit, From a viewpoint from which sufficient intensity | strength is acquired, 400 N / mm or less is preferable.

  The protective material for trees can maintain its shape and strength for a long period of time when it is wound on a tree from the viewpoint of being used for the purpose of preventing the peeling of trees from birds and beasts when wound around the tree. It is desirable to biodegrade. The protective material for trees can be evaluated by the molecular weight retention after the wet heat test described later, for evaluating the shape and strength at the time of use. Moreover, the resin composition can be evaluated by a simple composting test described later for evaluating biodegradability.

  From the viewpoint of maintaining the shape and strength during use for a long time, the protective material for trees has a weight average molecular weight retention rate of 45% or more after a wet heat test for 1 week under the conditions of 70 ° C. and 70% RH, 50% or more is more preferable, and 52% or more is still more preferable. Moreover, there is no restriction | limiting in particular about the upper limit of molecular weight retention, However, From a viewpoint of ensuring biodegradability, 85% or less is preferable and 80% or less is more preferable.

  From the viewpoint of obtaining sufficient biodegradability, the protective material for trees is preferably a material in which a sample of 50% or more and less than 90% disintegrates in a simple compost test under the conditions of 60 ° C. and 1 week described later, and a sample of 90% or more. More preferred is a material that collapses.

  Hereinafter, the present invention will be described in more detail based on examples carried out in order to clarify the effects of the present invention. In addition, this invention is not limited at all by the following examples and comparative examples.

<Measurement and evaluation method>
The measurement methods and evaluation methods for various physical properties in Examples and Comparative Examples are as follows.

(1) Evaluation of slipperiness The slipperiness was evaluated by measuring the coefficient of static friction. Using a tensile tester based on JIS K-7125, the static friction coefficient was determined when the front and back sides of a pair of protective materials for trees were joined in a 23 ° C., 50% RH environment. The weight of the thread (weight) around which the upper tree protective material was wound was 200 g, and the tensile speed at the time of friction measurement was 100 mm / min. The evaluation criteria are shown below.
○: Dynamic friction coefficient is 0.8 or less ×: Dynamic friction coefficient exceeds 0.8

(2) Through-hole strength evaluation The through-hole strength was evaluated by a through-hole strength test. The penetration strength (N / mm) of the protective material for trees was measured under the conditions of a test needle diameter of 1.0 mm and a test speed of 200 mm / min. The evaluation criteria are shown below.
○: Through-hole strength is 50 N / mm or more ×: Through-hole strength is less than 50 N / mm

(3) Visibility evaluation Visibility was evaluated by the light transmittance of the protective material for trees. Using a spectrophotometer (model number: “U-4000”, manufactured by Hitachi, Ltd.) with an integrating sphere cut out into a size of 50 mm in the MD direction × 50 mm in the TD direction, and a wavelength of 240 nm to 800 nm The light transmittance was measured at a scanning period of 0.5 nm. Of the light transmittance values of the respective wavelengths, the evaluation was performed using the maximum light transmittance value. The evaluation criteria are shown below.
○: Maximum light transmittance at wavelengths from 240 nm to 800 nm is 40% or less ×: Maximum light transmittance at wavelengths from 240 nm to 800 nm exceeds 40%

(4) Molecular weight retention rate evaluation Molecular weight retention rate (%) = (weight average molecular weight after wet heat test / weight average molecular weight before wet heat test) x 100 (1)
○: Molecular weight retention is 45% or more ×: Molecular weight retention is less than 45%

(5) Biodegradability evaluation Biodegradability was evaluated by a simple compost test. After mixing 5 kg of commercially available dog food with 10 kg of horticultural humus in a commercially available household conposter, 500 ml of water was added to make a 200 mm thick buried soil. It consists of two 60mm x 150mm wire mesh (3mm mesh) in order to minimize the cord protective material for trees with a diameter of 2mm and a length of 10cm in contact with the outside and collapsing and scattering. The sample was bound through a sample holder and a thin wire was passed through the mesh. The protective material for trees was buried with the sample holder so as to be vertical in the embankment of the poster. In the sample holder, the lower base was placed at a height of 25 mm from the surface of the buried soil, and the upper base was placed at a height of 25 mm from the bottom of the buried soil. The temperature of the composter was constant at 60 ° C. One week later, the protective material for trees was taken out, and the state of the protective material for trees was visually observed to confirm the presence or absence of collapse. The state of the protective material for trees was evaluated by the area ratio of the protective material for trees before and after the test. The evaluation criteria are shown below. In the following evaluation criteria, “◎” or “又 は” was regarded as acceptable.
◎: Collapse is 90% or more ○: Collapse is 50% or more and less than 90% ×: Collapse is less than 50%

(6) Measurement of heat of crystal melting (ΔHm) The heat of crystal melting (ΔHm) was measured according to JIS K-7121. About the sample cut out to about 10 mg, the temperature was increased from 30 ° C. to 200 ° C. at a rate of 10 ° C./min using DSC-7 manufactured by Perkin Elmer Co., and from the obtained thermogram, the heat of crystal melting (ΔHm) It was measured by reading.

(7) Measurement of storage elastic modulus (E ') It measured as dynamic viscoelasticity measured with a viscoelasticity spectrometer (model number "DVA-200", the IT measurement company make). The sample was compressed for 1 minute at a load of 20 MPa with a hot press heated at a set temperature of 180 ° C. or higher and 230 ° C. or lower, then cooled and formed into a sheet to obtain a film. The obtained film was accurately cut into a size of 4 mm wide × 80 mm long to obtain a measurement sample. The dynamic viscoelasticity was measured in the measurement temperature range of −100 ° C. to 200 ° C. under the conditions of vibration frequency 10 Hz, strain 0.1%, heating rate 3 ° C./min, and chuck 1 cm.

(8) Comprehensive evaluation Comprehensive evaluation was implemented based on slipperiness evaluation (static friction coefficient), through-hole strength evaluation, visibility evaluation (light transmittance), molecular weight retention evaluation, and biodegradability evaluation. The evaluation criteria are shown below.
○: Each evaluation is ○ or more ×: Any of each evaluation is ×

Example 1
Polylactic acid resin (a) -1 as polylactic acid resin (A) (polylactic acid, trade name “NW4032D”, manufactured by Nature Works, ratio of poly D lactic acid = 1.5 mol%, ratio of poly L lactic acid = 98.5 mol%, weight average molecular weight = 200,000, ΔHm = 42 J / g) and inorganic filler (b) -1 as a light scattering agent (B) (talc, trade name “SG-1000”, Japan Talc Co., Ltd., average particle size = 2.0 μm, refractive index = 1.56), so that the polylactic acid resin (a) -1 and the inorganic filler (b) -1 have a mass ratio of 95: 5. A resin composition was prepared by blending. Next, the produced resin composition was extruded at 210 ° C. with a φ25 mm same-direction twin screw extruder to obtain an extruded sheet. Next, the obtained extruded sheet was quenched with a casting roll at about 50 ° C. to obtain an unstretched sheet. The unstretched sheet was adjusted for the amount of molten resin discharged from the extruder and the line speed so that the average thickness was 160 μm.

  Next, using a stretcher, the obtained unstretched sheet was sequentially stretched 2.5 times in the longitudinal direction and 2.5 times in the width direction under the temperature condition of 80 ° C. (area magnification: 6.25 times). After that, heat treatment was performed at a temperature of 140 ° C. in a heat treatment oven to produce a stretched film (protective material for trees) having a thickness of about 25 μm. The slipping property, penetration strength, visibility, molecular weight retention, and biodegradability of the produced protective material for trees were evaluated. The evaluation results are shown in Table 1 below.

(Example 2)
A protective material for trees was prepared and evaluated in the same manner as in Example 1 except that the polylactic acid-based resin (a) -1 and the inorganic filler (b) -1 were blended so as to have a mass ratio of 90:10. did. The evaluation results are shown in Table 1 below.

(Example 3)
Instead of the inorganic filler (b) -1, the inorganic filler (b) -2 (anatase type titanium oxide, trade name: “A-1”, manufactured by Sakai Chemical Co., Ltd., average particle size = 0.15 μm, refractive index = 2.52) and the same as Example 1 except that the polylactic acid resin (a) -1 and the inorganic filler (b) -2 were blended so that the mass ratio was 96: 4. Thus, a protective material for trees was produced and evaluated. The evaluation results are shown in Table 1 below.

Example 4
Furthermore, incompatible resin (b) -3 (polybutylene adipate terephthalate (PBTA) trade name: “Ecoflex F”, manufactured by BASF, storage elastic modulus E ′ = 23 MPa), polylactic acid resin ( Trees in the same manner as in Example 1 except that a) -1, inorganic filler (b) -1 and incompatible resin (b) -3 were blended so that the mass ratio was 80:10:10. A protective material was prepared and evaluated. The evaluation results are shown in Table 1 below.

(Example 5)
Instead of the inorganic filler (b) -1, an incompatible resin (b) -4 (polystyrene, trade name: “G9305”, manufactured by PS Japan, storage elastic modulus E ′ = 2400 MPa) was used. A protective material for trees was produced and evaluated in the same manner as in Example 1 except that the lactic acid resin (a) -1 and the inorganic filler (b) -4 were blended so as to have a mass ratio of 90:10. . The evaluation results are shown in Table 1 below.

(Comparative Example 1)
Except that the polylactic acid-based resin (a) -1 and the inorganic filler (b) -1 were blended so as to have a mass ratio of 99.92: 0.08, a protective material for trees was obtained in the same manner as in Example 1. Fabricated and evaluated. The evaluation results are shown in Table 1 below.

(Comparative Example 2)
A protective material for trees was produced and evaluated in the same manner as in Example 1 except that the inorganic filler (b) -1 was not used. The evaluation results are shown in Table 1 below.

(Comparative Example 3)
The incompatible resin (b) -3 was used in place of the incompatible resin (b) -1, and the polylactic acid resin (a) -1 and the incompatible resin (b) -3 had a mass ratio of 80. : A protective material for trees was produced and evaluated in the same manner as in Example 1 except that the amount was 20. The evaluation results are shown in Table 1 below.

(Comparative Example 4)
The slipperiness, penetration strength, visibility, molecular weight retention, and biodegradability of the polyethylene protective material (c) -1 made of polyethylene resin (C) were evaluated. The evaluation results are shown in Table 1 below.

Each component described in Table 1 is shown below.
(A) -1: Polylactic acid resin (a) -1: Polylactic acid (trade name “NW4032D”, manufactured by Nature Works, ratio of poly-D lactic acid = 1.5 mol%, ratio of poly-L lactic acid = 98. 5 mol%, weight average molecular weight = 200,000, ΔHm = 42 J / g)
(B) -1: Inorganic filler (b) -1: Talc (trade name “SG-1000”, manufactured by Nippon Talc Co., Ltd., average particle diameter = 2.0 μm, refractive index = 1.56)
(B) -2: Inorganic filler (b) -2: Anatase type titanium oxide (trade name: “A-1”, manufactured by Sakai Chemical Industry Co., Ltd., average particle size = 0.15 μm, refractive index = 2.52)
(B) -3: Incompatible resin (b) -3: Polybutylene adipate terephthalate (PBTA) (trade name: “Ecoflex F”, manufactured by BASF Corporation, storage elastic modulus E ′ = 23 MPa)
(B) -4: Incompatible resin (b) -4: Polystyrene (trade name: “G9305”, manufactured by PS Japan, storage elastic modulus E ′ = 2400 MPa)
(C) -1: polyethylene protective material for trees

  As can be seen from Table 1, according to the protective material for trees having the polylactic acid resin (A) as a main component and the maximum light transmittance at a wavelength of 240 nm to 800 nm of 40% or less, the slipperiness, the through hole strength, the visual recognition Excellent results were obtained in all the evaluations of the property, the molecular weight retention rate and the biodegradability (Example 1-5). From this result, the protective material for trees according to Example 1-5 possesses suitable physical properties and workability at the start of use, and finally biodegrades while maintaining a suitable shape and strength during the use period. It turns out that the protective material for trees is obtained. On the other hand, when the polylactic acid resin (A) is not used as the main component, the slipperiness, visibility, and biodegradability are significantly deteriorated while being excellent in slipperiness (Comparative Example 4). Further, even when the polylactic acid resin (A) is a main component, it is understood that sufficient visibility cannot be obtained when the maximum light transmittance at a wavelength of 240 nm to 800 nm exceeds 40% (comparison). Example 1-3). Moreover, when Example 1-5 is compared with Comparative Examples 1 and 2, it turns out that slip property becomes still better by containing a light-scattering agent (B).

Claims (11)

It is a protective material for trees that prevents tree peeling damage by wrapping around the tree,
A protective material for trees comprising a resin composition comprising a polylactic acid resin (A) as a main component and having a light transmittance of 40% or less in a wavelength range of 240 nm to 800 nm.   The tree protective material according to claim 1, wherein the resin composition further contains a light scattering agent (B).   The tree protective material according to claim 2, wherein the light scattering agent (B) contains an inorganic filler (B-1).   The protective material for trees of Claim 3 whose compounding quantity of the said inorganic filler (B-1) is 0.1 to 30 mass% with respect to the total mass of the said resin composition.   The light scattering agent (B) contains an incompatible resin (B-2) that is incompatible with the inorganic filler (B-1) and the polylactic acid resin (A). The protective material for trees as described.   The blending amount of the inorganic filler (B-1) is 0.1% by mass to 30% by mass with respect to the total mass of the resin composition, and the incompatible resin (B-2). The protective material for trees according to claim 5 whose compounding quantity is 5 mass% or more and 18 mass% or less.   The protective material for trees according to any one of claims 3 to 6, wherein a refractive index of the inorganic filler (B-1) is 1.50 or more.   The tree protective material according to claim 2, wherein the light scattering agent (B) contains an incompatible resin (B-2) that is incompatible with the polylactic acid resin (A).   The protective material for trees of Claim 8 whose compounding quantity of the said incompatible resin (B-2) is 5 to 18 mass% with respect to the total mass of the said resin composition.   The protective material for trees according to any one of claims 1 to 9, wherein a molecular weight retention of a weight average molecular weight after one week has passed under a condition of 70 ° C and 70% RH is 45% or more.   The protective material for trees according to any one of claims 1 to 10, which is a stretched film.