WO2007046174A1

WO2007046174A1 - Biodegradable multilayered film with sealant layer

Info

Publication number: WO2007046174A1
Application number: PCT/JP2006/314253
Authority: WO
Inventors: Hisao Koike; Yosuke Takahashi
Original assignee: Asahi Kasei Chemicals Corporation
Priority date: 2005-10-17
Filing date: 2006-07-19
Publication date: 2007-04-26
Also published as: JPWO2007046174A1; JP4916447B2

Abstract

A biodegradable packaging film which has a specific coefficient of dynamic friction (µd) even immediately after film formation, changes little in the coefficient of dynamic friction (µd) during use, and has excellent suitability for use on packaging machines. It is a biodegradable multilayered film having a sealant layer on at least one surface thereof, and is characterized in that the sealant layer comprises a mixture of a polylactic acid resin (A), an aliphatic polyester resin (B) having a glass transition temperature Tg of 10°C or lower and a melting point of 70-120°C, and a lubricant (D), the (A)/(B) mixing ratio being from 55/45 to 13/87 by mass and the amount of (D) being 0.01-0.5 parts by mass per 100 parts by mass of the sum of (A) and (B), and that the surface has a coefficient of dynamic friction (µd) of 0.15-0.5.

Description

Specification

Multilayer film with biodegradable sealant layer

Technical field

The present invention relates to a multilayer film with a biodegradable sealant layer having excellent packaging machine suitability. In particular, the present invention relates to a multilayer film with a biodegradable sealant layer having excellent slipperiness and a low-temperature sealing function, and a method for producing the same. Furthermore, the present invention relates to a bag-like article and a cushioning material using the film.

Background art

[0002] Synthetic polymer compounds have come to be used extensively as plastics with excellent properties. However, the amount of waste is increasing with the increase in the amount of use, and how to dispose of this plastic is a big social problem. When incinerated, there is a problem that the amount of heat generated is large, so that the incinerator is likely to be damaged, and that harmful substances may be generated. There is also a problem that it will remain in the environment indefinitely because it is difficult to disassemble when it is landfilled. Furthermore, considering the cost of separation / recovery and regeneration, complete problem solving is difficult by recycling alone.

[0003] Amid the growing interest in such environmental problems, biodegradable plastics that decompose in the natural environment after disposal in order to reduce environmental burden and make society sustainable Is now required! /

[0004] On the other hand, one of the packaging forms of plastic film is bag-packed packaging, such as pillow packaging, overlap packaging, two-sided / three-sided / four-sided sealed packaging, liquid bags, and retort packaging. In recent years, continuous packaging machines for performing such packaging have been on the development trend of higher speed, and the required characteristics for the packaging film to be used have become severe!

[0005] The main characteristics required for the film used in these continuous packaging machines are low-temperature sealability and slipperiness. Low temperature sealability is a seal characteristic that enables high-speed packaging (bag making) of films by enabling heat sealing at lower temperatures. The heat seal is to stack a plurality of films, and heat and pressurize them using a heating bar, a heating plate or a heating roll, and adhere the films. Therefore, it has excellent low-temperature sealability. Lums are those that can be bonded in a short time in a wide range of temperatures and have sufficient adhesive strength for practical use. Furthermore, in film applications that have a sealing function for the purpose of sealing, storing, and holding the contents of liquids and gases, leakage of the liquids and gases that are the contents from the sealing part is prevented. Therefore, the sealing and airtightness of the seal part is one of the very important sealing functions.

[0006] The slipperiness means the dynamic friction coefficient d) between the metal surface of the packaging machine and the film surface in the film packaging process. In particular, a film having an appropriate coefficient of dynamic friction (d) is required for use in a packaging machine having a half-fold function or a packaging machine that changes the film feeding direction. In particular, when the seal surface is in contact with the metal surface of the half-folding jig, the dynamic friction coefficient d) between the seal surface and the metal surface is important. In addition, higher packaging speeds will tighten the requirements for film! /.

[0007] Under such circumstances, Patent Document 1 synthesized from glycol and an aliphatic dibasic acid or an acid derivative thereof having a sealing function and a melting point of 70 ° C to 200 ° C. Aliphatic polyesters are disclosed. Patent Document 2 discloses a biaxially stretched laminated film of substantially amorphous polylactic acid and an aliphatic polyester copolymer, and Patent Document 3 discloses a copolymer of substantially amorphous polylactic acid and aliphatic polyester. Compositions of coalesced and aliphatic aromatic polyester copolymers are disclosed. These disclosed films are films having a low-temperature sealing property, and low melting point aliphatic polyesters having a melting point of 70 ° C. to 120 ° C., in particular, have a stable dynamic friction coefficient (μd) over time. There was a problem with this!

[0008] In Patent Document 4, 3 to 70 parts by weight of a biodegradable aliphatic polyester having a glass transition point Tg of 0 ° C or less is blended with 100 parts by weight of a crystalline polylactic acid polymer. In addition, a method is described in which the stretchability of the stretched polylactic acid film is improved by stretching in at least a uniaxial direction and applying heat treatment. Patent Document 5 discloses a lactic acid polymer in which an aliphatic amide and an antiblocking agent are added to the lactic acid polymer. Patent Document 6 discloses a polylactic acid film in which the static friction coefficient and surface roughness between one side of the film are in a specific range. None of these disclosed polylactic acid-based films disclosed a film that has both low-temperature sealing properties and slipperiness, which are related to slipperiness of the film surface. [0009] Further, when a lubricant, particularly an organic lubricant, is used to control the slipperiness, the slipperiness depends on the amount of lubricant bleed out on the film surface. For this reason, in order to express the slippery immediately after film formation, a film with a composition having a high bleedout speed is required! Furthermore, since the amount of lubricant present on the film surface is in an equilibrium state at the storage temperature, for example, when the film is stored at a high temperature, the lubricant once bleeded out is impregnated into the film again and the slipperiness is poor. There are times. Therefore, depending on the storage temperature and storage period, the slipperiness of the film may be reduced, causing troubles during packaging (bag making). For this reason, a biodegradable sealant layer with excellent bag-making properties that can be applied to a high-speed packaging machine that always expresses a certain level of slipperiness immediately after film formation and within a period of use and has sufficient low-temperature sealability. I was asked for an attached film.

[0010] Patent Document 7 discloses a plastic packaging cushion as a pillow-type air cushioning material. The purpose of this publication is to form an inexpensive cushioning material that can be obtained from raw materials by connecting and forming hollow units so that the units can work together as a unit. There is no disclosure about the slipperiness of the film that satisfies the suitability of the packaging machine (bag making machine), and nothing about the material and the biodegradable polymer. Patent Document 8 discloses an airbag cushioning material sheet that is inflatable and includes a self-sealing valve. Nylon and polyethylene laminate films have been disclosed as heat-sealable, non-breathable, flexible and have some mechanical strength. An airbag cushioning material using a degradable film is not disclosed.

[0011] Patent Document 1: Japanese Patent No. 2759596

Patent Document 2: Japanese Patent Application Laid-Open No. 2004-306482

Patent Document 3: Japanese Patent Laid-Open No. 2004-244553

Patent Document 4: Japanese Unexamined Patent Application Publication No. 2004-10900

Patent Document 5: Japanese Unexamined Patent Application Publication No. 2005-146200

Patent Document 6: Japanese Patent Application Laid-Open No. 2004-331860

Patent Document 7: Japanese Utility Model Publication No. 59-10274

Patent Document 8: Japanese Patent Laid-Open No. 4 154570 Disclosure of the invention

Problems to be solved by the invention

[0012] The present invention provides a multilayer with a biodegradable sealant layer that expresses a specific dynamic friction coefficient (d) immediately after film formation, has a small change in the dynamic friction coefficient d) within the period of use, and can be sealed at low temperature. The object is to provide a film. That is, an object of the present invention is to provide a multilayer film with a biodegradable sealant layer that can smoothly feed a film in a packaging (bag making) machine and has excellent suitability for a high-speed packaging machine. It is another object of the present invention to provide a biodegradable packaging film, a bag-like article, and an air cushioning material that have a sufficient sealing function and are excellent in holding contents.

Means for solving the problem

[0013] As a result of intensive studies to solve the above problems, the present inventors have found that in a multilayer film with a biodegradable sealant layer, a low melting point aliphatic polyester resin (B) and polylactic acid. By mixing (A) and the lubricant (D) at a specific ratio, a composition was found in which the bleed-out speed of the lubricant was increased. As a result, an appropriate dynamic friction coefficient (d) was developed immediately after film formation, enabling smooth film feeding and low-temperature sealing in a packaging (bag making) machine. Furthermore, even when the film is stored at a high temperature, the lubricant bleeds out as soon as it is returned to room temperature (use environment temperature), and an appropriate dynamic friction coefficient d) can be developed. As a result, a film having a stable dynamic friction coefficient (d) and having high-speed packaging suitability was obtained immediately after film formation within the trial period, and the present invention was achieved. Furthermore, by using a specific seal strength and multilayer structure, a biodegradable bag-like article and an air cushioning material were found, and the present invention was completed.

That is, the present invention is as follows.

(1) A biodegradable multilayer film having a sealant layer on at least one surface, and the sealant layer has a polylactic acid resin (A) and a glass transition temperature Tg of 10 ° C or lower and a melting point of 70 ° It consists of a mixture of aliphatic polyester-based resin (B) and lubricant (D) at a temperature not lower than C and not higher than 120 ° C. The mixing mass ratio of (A) and (B) is (A) / (B) = 55Z45-13Z87 (D) is 0.01 to 0.5 parts by mass with respect to 100 parts by mass of (A) and (B), and the coefficient of dynamic friction d) of the surface with the sealant layer is 0. Many with biodegradable sealant layer 15 or more and 0.5 or less Layer film.

(2) The polylactic acid-based resin (A) is a substantially non-crystalline polylactic acid-based resin having a molar ratio of L-lactic acid and D-lactic acid constituting the resin of 92 Z8 to 8Z92. A multilayer film with a biodegradable sealant layer as described in (1) above.

(3) The multilayer film with a biodegradable sealant layer according to (1) or (2) above, wherein the aliphatic polyester-based resin (B) has a melting point of 70 ° C or higher and 85 ° C or lower.

(4) A crystal nucleating agent (C) is further included, and the amount of the crystal nucleating agent (C) added is 100 parts by mass of the total amount of the polylactic acid-based resin (A) and the aliphatic polyester-based resin (B). The multilayer film with a biodegradable sealant layer according to the above (3), which is 0.5 parts by mass or more and 43 parts by mass or less.

(5) The crystal nucleating agent (C) is an aliphatic polyester-based resin (C2), and the melting point of the aliphatic polyester-based resin (C2) is higher than 85 ° C and lower than 170 ° C. A multilayer film with a biodegradable sealant layer as described in (4).

(6) The multilayer film with a biodegradable sealant layer according to the above (5), wherein the aliphatic polyester-based resin (C2) has a molecular weight of 170,000 or less.

(7) The multilayer film with a biodegradable sealant layer according to any one of (1) to (6), wherein the lubricant (D) is a fatty acid amide

(8) The molar ratio of L-lactic acid and D-lactic acid that make up the fat is 95Z5 ～: LOOZO polylactic acid and the nucleating power, and the differential scanning calorimetry at 10 ° CZ min. A heat-resistant layer with a melting point (Tm) of 140 ° C to 170 ° C and a relationship between heat of fusion (ΔHm) and heat of crystallization (ΔHe) (ΔHm—ΔHe) of 15jZg to 60jZg The multilayer film with a biodegradable sealant layer according to any one of the above (1) to (7), comprising at least one layer.

(9) Co-extrusion of the resin constituting each layer, and in the molten state, the film is melt-stretched under the conditions where the draw ratio is 40 to 200 times in terms of area magnification. A method for producing a multilayer film with a biodegradable sealant layer as described in any of the above.

(10) A bag-like article using the biodegradable packaging film according to any one of (1) to (7) above.

(11) An airbag cushioning material using the biodegradable packaging film described in any one of (1) to (7) above.

The invention's effect [0014] The multilayer film with a biodegradable sealant layer of the present invention has a low-temperature sealing property and has little change with time in the dynamic friction coefficient d) during the period of use immediately after film formation. Therefore, it is possible to smoothly feed the film in a packaging (bag making) machine, and there is an effect that expresses excellent suitability for a packaging (bag making) machine even in high-speed packaging. In addition, in order to develop sufficient seal strength, there is an effect of holding liquid or gas contents without leaking.

BEST MODE FOR CARRYING OUT THE INVENTION

[0015] The present invention will be specifically described below. The multilayer film with a sealant layer of the present invention comprises a base material layer and a sealant layer. The base material layer is a layer that provides mechanical properties generally required as a packaging film, for example, physical properties such as tensile strength, elastic modulus (rigidity), tear strength, puncture strength, and layers that provide functionality. It consists of an adhesive layer for bonding these layers. Specific examples of functionality include barrier properties, heat resistance, light shielding properties, and chemical resistance.

[0016] The sealant layer of the present invention comprises an aliphatic polyester-based resin (B) and an aliphatic polyester-based resin (B) having a glass transition temperature Tg of 10 ° C or lower and a melting point of 70 ° C or higher and 120 ° C or lower. ) Is a mixture mass ratio of (A) Z (B) = 55Z45 to 13Z87, and it is important that the mixed composition contains a lubricant (D). The mechanism by which the bleed-out speed of the lubricant is increased is accurately grasped. V, N, but the polylactic acid (A), which is incompatible with the aliphatic polyester-based rosin (B), is blended into the film. It is thought that the interface of the resin blended with the resin is formed, and the bleed-out speed of the lubricant is increased. For this reason, it is considered that the change with time of the dynamic friction coefficient d) during the period of use becomes small! When the mixing mass ratio of polylactic acid-based resin (A) is higher than (A) / (B) = 55/45, polylactic acid-based resin forms a matrix, so it has a low-temperature sealing property, that is, a short seal. In time, it is difficult to obtain an appropriate seal strength. Specific mass ratio of polylactic acid-based rosin (A) S (A) Z (B) = When less than 13Z87, it can be manufactured with fewer interfaces of polylactic acid-based rosin formed in the matrix of (B). It is difficult to develop slipperiness from the beginning of the film. A more preferable mixing mass ratio is (A) Z (B) = 55/45 to 15/85, and this is more preferable (A) / (B) = 30/70 to 15/85, and More preferably, (Α) Ζ (Β) = 25Ζ75 to 15Ζ85.

[0017] The polylactic acid-based rosin (Α) used in the present invention is an aliphatic polyester mainly composed of lactic acid, and a copolymer containing 50% or more of lactic acid homopolymer and Z or lactic acid monomer units. A copolymer of lactic acid with another hydroxycarboxylic acid and a ich compound selected from the group consisting of z or latatones. As monomers used as a copolymerization component with lactic acid, hydroxycarboxylic acids include glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 3-hydroxyvaleric acid, 4-hydroxyvaleric acid, 6-hydroxycaproic acid, etc. Is mentioned. Examples of the aliphatic cyclic ester include glycolide, lactide, β-proviolatatone, Ύbutyrorataton, δ valerolataton, ε-one-prolataton, and latatones substituted with various groups such as a methyl group.

[0018] In the present invention, it is preferable to use a substantially amorphous polylactic acid-based rosin (mushroom) in which the molar ratio of L-lactic acid to D-lactic acid constituting the rosin is 92 to 8 to 92. Substantially amorphous polylactic acid-based resin is the heat of fusion (ΔHm) and crystallization heat (ΔHe) determined by differential scanning calorimetry (according to CFIS-K7122) at 10 ° CZ min. This means a polylactic acid-based resin (A) having a relationship (ΔHm—ΔHe) of 3J Zg or less. If the molar ratio of L-lactic acid or D-lactic acid exceeds 92%, the polylactic acid resin (A) easily crystallizes depending on the film forming conditions. Since this crystal does not melt at the sealing temperature, it functions to reduce the sealing strength. The more realistic and preferred molar ratios of L-lactic acid and D-lactic acid are 90 ZlO to 75 Z25 and 10 to 90 to 25 75.

[0019] The aliphatic polyester-based resin (B) having a glass transition temperature Tg of 10 ° C or lower and a melting point of 70 ° C or higher and 120 ° C or lower used in the present invention was produced by a microorganism. Aliphatic polyester-based resin, for example, aliphatic polyesters such as poly (hydroxyalkanoic acid) biosynthesized in bacterial cells, and chemically synthesized aliphatic polyester-based resin, such as aliphatic dicarboxylic acids and aliphatic diols. Examples include polycondensed aliphatic polyesters, aliphatic polyesters obtained by ring-opening polymerization of cyclic lanthanides, synthetic aliphatic polyesters, and types of resins and mixtures thereof partially modified in their chemical structure. Can be mentioned. Aliphatic carboxylic acids such as succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, and dodecanedioic acid, which are polycondensed from aliphatic dicarboxylic acid and aliphatic diol as main components, Examples thereof include polycondensation in which one or more aliphatic diols such as ethylene glycol, 1,3 propion glycol, 1,4 butanediol and 1,4-cyclohexanedimethanol are selected. Annular rataton Examples of the aliphatic polyesters obtained by ring-opening polymerization of polymers include ring-opening polymers selected from one or more cyclic monomers such as ε-force prolatatatone, δ-valerolacton, and j8-methyl-δ valerolataton. Examples of synthetic aliphatic polyesters include copolymers of cyclic acid anhydrides such as cono anhydride, succinic acid and ethylene oxide, propylene oxide, and oxiranes. Of the above, taking into account the crystallization speed and crystallinity, preferred examples include polybutylene succinate, poly (butylene succinate Ζ adipate), polyethylene succinate, poly (ethylene succinate Ζ adipate), polyhydroxyalkano Eate.

[0020] If the melting point of the above-mentioned aliphatic polyester resin (Β) is less than 70 ° C, problems such as blocking occur during storage of the raw film when handling the film during film formation and immediately exceed 120 ° C. In view of the high-speed bag-making property, the low-temperature sealing property is hardly exhibited. More preferably, it is 70 ° C or higher and 90 ° C or lower, more preferably 70 ° C or higher and 85 ° C or lower, and most preferably 75 ° C or higher and 85 ° C or lower.

[0021] As the lubricant (D) used in the present invention, an inorganic lubricant or an organic lubricant is used.

Examples of inorganic lubricants include talc, silica, zeolite, and mica. Examples of organic lubricants include fatty acid amides, fatty acid salts, silicon compounds, and waxes. Examples of fatty acid amides include caproic acid amide, force prillic acid amide, force puric acid amide, lauric acid amide, myristic acid amide, palmitic acid amide, stearic acid amide, arachidic acid amide, behenic acid amide, and palmitoleic acid amide. , Oleic acid amide, eicosenoic acid amide, erucic acid amide, elaidic acid amide, trans-11-eicosenoic acid amide, trans-13 docosenoic acid amide, linoleic acid amide, linolenic acid amide, ricinoleic acid amide, ethylenebis stearic acid amide , L force acid amide and the like. Examples of the fatty acid salt include zinc stearate, calcium stearate, magnesium stearate, aluminum stearate, barium stearate, lithium stearate, lead stearate, sodium oleate, barium laurate, and zinc laurate. Also, methyl laurate, methyl myristate, methyl palmitate, methyl stearate, methyl oleate, methyl erucate, methyl behenate, butyl laurate, butyl stearate, isopropyl myristate, isopropyl palmitate, palmitate Octyl acid, palm fatty acid octyl ester, stearic acid Examples thereof include monoester organic lubricants such as octyl, lauryl laurate, stearyl long stearate, long-chain fatty acid higher alcohol ester, behenine behenate, cetyl myristate and the like. Among these, organic lubricants are preferably used. Among these, fatty acid amides are preferred, and L-force acid amide, ethylenebisstearic acid amide, stearic acid amide and the like are used.

[0022] The addition amount of the lubricant (D) is 100 parts by mass with respect to the total amount of the polylactic acid-based resin (A) and the aliphatic polyester-based resin (B) having a glass transition temperature Tg of 10 ° C or less. 0.01 to 0.5 parts by mass. If it is less than 01 parts by mass, it is difficult to obtain the effect of reducing the dynamic friction coefficient d) on the surface of the packaging film. If it exceeds 0.5 parts by mass, the dynamic friction coefficient (d) on the surface of the packaging film will be too low, which will be described later. This may affect handling problems and reduce seal strength. A more preferable range is 0.05 to 0.3 parts by mass.

[0023] The dynamic friction coefficient (μd) is a physical property related to the slipperiness of the packaging film. By setting the dynamic friction coefficient (μd) in the range of 0.15 or more and 0.5 or less, excellent suitability for the packaging machine is achieved. To express. If it is less than 0.15, the roll will be unwound by itself, or it may be difficult to handle the roll when the film is formed and wound. If it exceeds 0.5, troubles such as film breakage due to poor sliding are likely to occur in the packaging machine. In consideration of the high-speed bag-making property, a more preferable dynamic friction coefficient d) is 0.17 or more and 0.45 or less, and more preferably 0.2 or more and 0.4 or less.

In the present invention, when the melting point of the aliphatic polyester-based resin (B) is 70 ° C. or higher and 85 ° C. or lower, the crystal nucleating agent (C) is preferably used. The aliphatic polyester resin (B) having a melting point in the above-mentioned range has a low crystallization rate and a low crystallinity, and therefore has a non-slip property when used on the film surface. Therefore, by using the crystal nucleating agent (C), it is possible to improve the crystallinity and crystallization speed of the aliphatic polyester resin (B). As a result, the bleed-out speed of the lubricant (D) is improved, and it is considered that more stable slidability can be expressed over time. As such a crystal nucleating agent (C), in addition to inorganic fillers and layered silicates having a particle size of 10 μm or less, fatty acid salts and aliphatic polyester-based rosins can be used. As the inorganic filler, talc and silica can be used, and as the layered silicates, montmorillonite and mica are used. In addition, for the purpose of improving dispersibility, the surface of the inorganic filler is treated with silane power. A filler that has been surface-treated by pulling or the like can also be used. Examples of fatty acid salts include zinc stearate, calcium stearate, magnesium stearate, aluminum stearate, barium stearate, lithium stearate, lead stearate, sodium oleate, barium laurate, zinc laurate and the like. From the viewpoint of sealing properties, the crystalline nucleating agent (C) is preferably an aliphatic polyester-based resin.

[0025] As the aliphatic polyester-based resin (C2) used as the crystal nucleating agent (C), those having the same structure as the aliphatic polyester-based resin (B) described above can be used. In particular, the melting point (Tmc) of the aliphatic polyester-based resin (C2) is preferably higher than 85 ° C and lower than 170 ° C. When Tmc is higher than 85 ° C, the effect can be exhibited as a crystal nucleating agent (C) for a low-temperature sealant layer. A Tmc of 170 ° C or higher is not preferable because it affects the melting characteristics during extrusion. More preferable (Tmc) is 90 ° C or higher and 120 ° C or lower.

[0026] The relationship between the crystallization temperature (Tec) of the aliphatic polyester resin (C2) used as the crystal nucleating agent (C) and the crystallization temperature (Tcb) of the aliphatic polyester resin (B) is 10 ° C. Those with ≤ (Tcc-Tcb) ≤100 ° C are preferably used. If 10 ° C> (Tec—Tcb), the aliphatic polyester-based resin (C2) may not be effective enough as a crystal nucleating agent, and if (Tcc-Tcb)> 100 ° C The crystallization temperature is too high, which may cause problems with low-temperature sealing. More preferably, 15 ° C ≦ (Tec—Tcb) ≦ 50 ° C.

[0027] As the aliphatic polyester-based resin (C2), those having a weight average molecular weight (Mw) of 80,000 to 170,000 are suitably used. By setting it as such molecular weight, there exists an effect which makes the crystallization speed | rate of an aliphatic polyester type | system | group resin (B) faster. Furthermore, since the fluidity of the resin at the time of sealing is improved, there is also an effect that enables sealing with better airtightness. When the weight average molecular weight exceeds 170,000, the effect of improving airtightness at the time of sealing is small, and when the weight average molecular weight is less than 80,000, hydrolysis of the aliphatic polyester-based resin (B) is promoted. May reduce the strength of the steel. A more preferred weight average molecular weight is 100,000 or more and 150,000 or less.

[0028] The mixture of the aliphatic polyester-based resin (B) and the crystal nucleating agent (C) used in the sealant layer of the present invention is cooled at 10 ° CZ by differential scanning calorimetry CFIS-K-7122). The crystallization heat amount ΔHe sometimes obtained is preferably from lOjZg to 50jZg. Such crystallization By having the degree, more stable slipperiness can be expressed. If it is less than lojZg, the stability of slipperiness may be a problem, and if it exceeds 50 jZg, flexibility may be a problem. AHc is more preferably 18jZg or more and 40jZg, and still more preferably 20jZg or more and 35jZg or less.

[0029] The content of the crystal nucleating agent (C) is preferably 0.5% by mass to 40% by mass in the sealant layer in a range that does not inhibit the function of the sealant layer. If it is less than 5% by mass, the effect as a crystal nucleating agent such as improvement in crystallization degree and crystallization speed is difficult to be manifested. If it exceeds 40% by mass, problems such as hindering the sealability at low temperatures. May occur. A more preferred amount of added calories is 1% to 30% by mass, more preferably 2% to 20% by mass, and most preferably 3% to 15% by mass.

[0030] The packaging film of the present invention preferably has a heat seal strength of 15 NZl5 mm or more and 40 NZl5 mm or less. 15NZ If it is less than 15mm, when some force is applied to the packaged film, if the seal surface peels off immediately and exceeds 40NZl5mm, it is easy to form a packaging film that is difficult to open. A more preferable seal strength is 17 NZl 5 mm or more and 35 N Zl 5 mm or less, and further preferably 20 NZl 5 mm or more and 30 NZl 5 mm or less. Further, it is preferable that the sealing can be performed within a second of sealing because packaging at a higher speed is possible. More preferably, it is preferable to be able to seal within a short time of 0.5 seconds or less, and more preferably within 0.2 seconds! /.

[0031] The multilayer film with a biodegradable sealant layer of the present invention has a base material layer in addition to the sealant layer, and the layer structure is an asymmetrical structure such as a two-type two-layer or a three-type three-layer, or a two-type three-layer. It can be a symmetrical structure such as a layer, 3 types, 5 layers, etc. As described above, the base material layer is composed of a layer having mechanical properties required for a packaging film or a functional layer, such as a heat-resistant layer, a barrier layer, a light-shielding layer, a chemical-resistant layer, and the like. It consists of an adhesive layer for bonding these layers. Further, it may be a layer that exhibits two or more functions, for example, an adhesive layer having excellent mechanical properties or an adhesive layer having a light shielding function. Among such combinations, a three-layer three-layer structure or a three-layer five-layer structure of a heat-resistant layer, an intermediate layer (a layer excellent in mechanical properties or a layer that exhibits other functions), and a sealant layer is preferably used. As a specific example, the thickness of each layer is 3 μm or more and 50 μm or less. The thickness is preferably 5 μm or more and 35 μm or less, and more preferably 8 μm or more and 20 μm or less. If it is 3 m or less, the sealing strength may not be sufficiently exhibited, and if it is 50 μm or more, economical viewpoint power is not preferable. The heat-resistant layer preferably has a thickness of 3 μm to 40 μm, more preferably 5 μm to 20 μm. Since the intermediate layer differs depending on the required function, it cannot be determined unconditionally, but it can be 5% to 80% of the total film thickness.

[0032] In the multilayer film with a biodegradable sealant layer of the present invention, a heat-resistant layer may be provided as one of the base material layers. In particular, the melting point (Tm) determined by differential scanning calorimetry CFIS-K 7121 and 7122 when heated at 10 ° CZ is 140 ° C to 170 ° C and the heat of fusion (ΔΗπι) and crystals It is preferably used as a main component of a polylactic acid based resin heat-resistant layer having a heat generation amount (ΔHe) relationship (ΔHm—ΔHe) of 15 jZg to 60 jZg. The melting point (Tm) is 140 ° C or higher, and the relationship between the heat of fusion (ΔHm) and the heat of crystallization (ΔHe) (ΔHm—ΔHe) is 15jZg or higher. Thus, heat resistance can be exhibited, and bag-making stability can be imparted. If Tm exceeds 170 ° C, from the viewpoint of influence on extrusion, and if (ΔΗπι-AHc) exceeds 60 jZg, it is not preferable from the viewpoint of film flexibility. Preferred (AHm-Δ-ο) is 20 jZg or more, more preferably 30 jZg or more. The preferred Tm is 150 ° C or higher, more preferably 160 ° C or higher. As such a polylactic acid-based resin, a polylactic acid-based resin having a molar ratio of L-lactic acid to D-lactic acid of 100Z0 to 95Z5 or 5Z95 to 0Z100 can be used. A polylactic acid-based resin of ˜95 to 5 is preferably used. In addition, it is possible to use a copolymer of polylactic acid-based resin having the above-mentioned ratio with other hydroxycarboxylic acid and a compound selected from the group consisting of Ζ or ratatones.

[0033] A crystal nucleating agent and a crystallization accelerator can be added to the heat-resistant layer in order to facilitate the crystallization of the polylactic acid-based resin. Preferred crystal nucleating agents are inorganic fillers and layered silicates having a particle size of 10 m or less. As the inorganic filler, talc or silica can be used. As the layered silicates, montmorillonite, mica and the like can be used. For the purpose of improving dispersibility, a filler obtained by subjecting the surface of the inorganic filler to a surface treatment such as silane coupling can also be used. Two or more types of crystal nucleating agents Can be used in combination. The amount of the crystal nucleating agent used in this case is 0.5 to 30 parts by mass, more preferably 1 to 20 parts by mass, and still more preferably 100 parts by mass of the resin in the heat-resistant layer. 2 parts by mass or more and 15 parts by mass or less. When the addition amount exceeds 30 parts by mass, the viewpoint power of transparency and flexibility of the film is not preferable. In addition, as the crystallization accelerator, a plasticizer, the above-described aliphatic polyester-based resin having a Tg of 10 ° C. or less, and Z or aromatic-aliphatic polyester-based resin can be added simultaneously. For example, polybutylene succinate, poly (butylene succinate Z adipate), polyethylene succinate, poly (ethylene succinate Z adipate), etc. as aliphatic polyester-based resin, (Butylene terephthalate Z adipate). In addition, polylactic acid and aliphatic polyester-based resin and Z or aromatic-aliphatic polyester-based resin can also be used. Examples of the plasticizer include aliphatic polycarboxylic acid esters, fatty acid polyhydric alcohol esters, oxyesters, and epoxy plasticizers. Specific examples include triacetin (TA), tributyrin (TB), butylphthalyl butyl dalicolate (BPBG), tributyl acetyl citrate (ATBC), dioctyl sebacate, triethylene glycol diacetate, glycerin esters, Examples include butyl oleate (BO), adipate ether'ester, epoxidized soybean oil (ESO), and the like.

[0034] The addition amount of these crystallization accelerators is preferably less than 30% by mass in the mass of the heat-resistant layer. If it exceeds 30% by mass, the film will be deformed at the temperature at the time of heat sealing, and the function of the heat-resistant layer cannot be performed immediately. Preferably, it is 20 mass% or less.

[0035] The multilayer film with a biodegradable sealant layer of the present invention includes an inorganic filler, an antiblocking agent, a heat stabilizer, an antioxidant, an ultraviolet absorber, an antifogging agent, an antistatic agent, an antifungal agent, and an anti-resistance. Do not impair the properties of the present invention with known additives such as impact modifiers! It is possible to mix in a range.

[0036] As the antistatic agent, a surfactant, carbon, conductive polymer, or the like can be used. Various known surfactants, for example, nonionic surfactants such as partial fatty acid esters of polyhydric alcohols, ionic surfactants typified by alkyl sulfonates, and quaternary grades. Using cationic surfactants typified by ammonium salt Rukoto can. A surfactant-based antistatic agent is Riken Master GSR350 (trade name) manufactured by Riken Vitamin Co., Ltd., and a static master BO (trade name) manufactured by Riken Technos Co., Ltd. is used as an antistatic agent for conductive polymers. )and so on. The addition of these antistatic agents, surface resistance of 10 ⁹ ~: can be controlled in a range of L0 ^12.

[0037] Various known pigments may be added for the purpose of blocking ultraviolet rays and visible light. Dairy Seika Co., Ltd.'s Early Master (product name) is a product containing facial and carbon. In particular, 1 to 5% by mass of carbons can be added in order to develop light shielding properties.

[0038] Next, a method for producing a multilayer film with a biodegradable sealant layer of the present invention will be described. As a method for forming the biodegradable multilayer film of the present invention, a conventional casting method such as a method of casting from a T die to a cooling roll, an inflation method, a tenter method, etc., unstretched, uniaxially stretched, or simultaneously Alternatively, there is a sequential biaxial stretching method. More specifically, it can be obtained by the following method.

(1) A method of forming a film by melting and stretching (stretching at a temperature equal to or higher than the melting point) a tube-shaped or sheet-shaped resin extruded in a molten state by an infusion method or a cast method in a molten state.

(2) After the tube-shaped or sheet-shaped resin extruded in the molten state is rapidly cooled and solidified in a state close to the amorphous state, the tube-shaped or sheet-shaped resin is subsequently converted into the glass transition temperature. Reheated to the melting point or lower and stretched by the inflation method or roll tenter method to form a film by the cold stretching method, and if necessary, after the melt stretching or cold stretching, to suppress the heat shrinkability of the film For this purpose, a film is obtained by heat treatment while holding the film.

[0039] The stretching ratio of the film or sheet is such that the final stretched film or sheet thickness is in the range of 1 Z200 times to 1Z40 times with respect to the distance between the extrusion die (die lip) regardless of the stretching method. In other words, it is preferable that the film is stretched at least in one axial direction so that the area force of the final stretched film or sheet is 0 to 200 times the area of the film or sheet immediately after the exit of the extrusion die (die lip). . (Hereafter, (area of film or sheet immediately after extrusion die (die lip) opening) ratio of Z (area of final stretched film or sheet) Is referred to as “area magnification”. )

Further, as a method for forming a multilayer film, in addition to the method for forming a multilayer film by coextrusion as described above, a method for producing a film by lamination (extrusion lamination or dry lamination) may be used. .

[0040] Among these methods, a method of stretching by 40 to 200 times the area magnification from the die outlet by melt stretching is particularly preferable. At this time, since the surface is roughened by cooling the surface of the packaging film, it is easier to express slipperiness. The area ratio of the die exit force during melt drawing is more preferably 60 to 150 times, and still more preferably 80 to 140 times.

[0041] Further, the multilayer film with a biodegradable sealant layer formed by the melt drawing method is annealed at a temperature in the vicinity of Tg of the heat-resistant layer, more specifically in a temperature range of Tg ± 30 ° C. By performing the treatment, the crystallinity of the heat-resistant layer is further improved, and the heat resistance, that is, the adhesion prevention property to the seal bar can be exhibited. Annealing at temperatures above 30 ° C above Tg causes film deformation and blocking, and annealing at temperatures below 30 ° C below Tg does not produce sufficient effects. A more preferable annealing temperature is (Tg—20) or more and 0 ^ + 15) or less, and more preferably (Tg−15) ° C. or more and Tg or less.

[0042] When the biodegradable packaging film obtained as described above is used for packaging in pillow packaging or overlap packaging, continuous high-speed packaging can be performed more stably. In particular, it can also be used for packaging of pocket tissues, ink cartridges, toner cartridges and the like. Furthermore, with the multilayer film of the present invention, a bag that can be stored and retained for a long period of time without the liquid or gas of the contents leaking from the seal portion can be obtained.

[0043] In addition, when used as a pillow type air cushioning material or an air cushioning material with a reverse support valve, it has excellent compression creep resistance and pressure strength with less air leakage, and practically sufficient cushioning performance for a long time. Sustainable air cushioning material is obtained.

Example

The present invention will be described based on examples.

[0045] The evaluation methods used in the examples and comparative examples are described below.

(1) Measurement of dynamic friction coefficient d) Measurement was performed based on ASTMD-1894, and the rider used for the measurement was made of 500 g of satin metal. In addition, after film formation, what was stored at room temperature for 24 hours was measured and used as the dynamic friction coefficient d) immediately after film formation, and after storage at room temperature for one year, the dynamic friction coefficient d) after one year was measured.

(2) D- and L-lactic acid composition and optical purity of polylactic acid polymer

The composition ratio of L-lactic acid and Z- or D-lactic acid monomer units constituting the polylactic acid polymer was adjusted with 1 N-HC1 after the sample was decomposed with 1 N NaOH and neutralized with distilled water, and the concentration was adjusted with distilled water. The hydrolyzed sample (liquid) was subjected to high-performance liquid chromatography (trade name: HPLC: LC-10A-VP) manufactured by Shimadzu Corporation equipped with an optical isomer separation column. From the detected peak area ratio (area measurement by perpendicular method), the weight ratio of L-lactic acid constituting the polylactic acid polymer [L] (unit%), the weight ratio of D-lactic acid constituting the polylactic acid polymer [D] (Unit%) was determined, and the arithmetic value (rounded off) of 3 points per polymer was taken as the measured value.

(3) Heat of fusion (ΔHm), heat of crystallization (ΔHe), crystallization temperature (Tc), melting point (Tm) Perkin-Elmer in accordance with JIS-K-7121 and 7122 Using a differential scanning calorimeter (DSC) manufactured at a nitrogen gas flow rate of 25 mlZ, the temperature was raised from 0 ° C to 200 ° C at 10 ° CZ, and the crystallization heat during the temperature rise Δ Η heat of fusion Δ Ηπι and melting point Tm were measured.

(4) Sinore strength (N / 15mm)

Film seal strength In accordance with IS-Z1707, the seal pressure is 0.665 MPa, the seal time is 0.2 seconds, and the seal strength is increased every 10 ° C in the temperature range from 80 ° C to the film fusing. The maximum value was measured as the seal strength of the film. A seal bar with a width of 5 mm was used.

(5) Packing machine suitability

Using a Tricon air cushion bag-making machine 150, bags were made at a rate of 150 pieces / minute, and evaluated according to the following indicators.

◯: Film breakage 0 times when the bag is made for 1000m

△: 1000m of raw fabric When the bag is made, the film breaks once or twice X: For 1000m of original fabric, the film breaks 3 times or more when the bag is made

(6) Air cushioning material Compression creep

In accordance with JIS-K-6767, a compression creep test was performed on one air cushion using a weight of 2 kg. At this time, the thickness of the air cushioning material after 1 day was used as the initial thickness, and the following indices were used for evaluation.

A: The thickness after 7 days is 80% or more of the initial thickness.

○: The thickness after 7 days is 20% or more of the initial thickness.

Δ: After 7 days, the air was completely removed.

X: After one day, it was completely out of air.

The biodegradable polymers used in the following examples and comparative examples are shown below. However, the composition of rosin in the present invention is not limited to this.

A1: Polylactic acid (Cargill Dow 4032D (trade name), D lactic acid content = 1.4%, molecular weight = 240,000, Tg = 58 ° C, Tm = 166 ° C)

A2: Polylactic acid (4042D (trade name) manufactured by Cargill Dow Co., Ltd., D lactic acid content = 4.2%, molecular weight = 230,000, Tg = 58.C, Tm = 158 ° C)

A3: Polylactic acid (Cargildau 4060D (trade name), D lactic acid content = 12.6%, molecular weight = 250,000, Tg = 58 ° C)

B1: Polybutylene succinate adipate (Pionore 5001 manufactured by Showa Polymer Co., Ltd.)

D (trade name), molecular weight = 240,000, Tg = —53 ° C, Tm = 79 ° C, Tc = 47 ° C)

B2: Polybutylene succinate adipate (Pionore # 300, Showa Polymer Co., Ltd.)

1 (trade name), molecular weight = 230,000, Tg =-43 ° C, Tm = 93 ° C, Tc = 66 ° C)

B3: Polybutylene succinate adipate (Pionole # 302, Showa Polymer Co., Ltd.)

0 (trade name), molecular weight = 140,000, Tg = 45 ° C, Tm = 92 ° C, Tc = 66 ° C)

B4: Polybutylene succinate (Pionore # 1001 manufactured by Showa Polymer Co., Ltd. (trade name)

), Molecular weight = 250,000, Tg = -32. C, Tm = 113. C, Tc = 88 ° C)

B5: Polybutylene succinate (Pionore # 1050 (product name, Showa Polymer Co., Ltd.)

), Molecular weight = 110,000, Tg = —33 ° C, Tm = 112 ° C Tc = 86 ° C)

Talc: LMS200 (trade name) manufactured by Fuji Talc Industrial Co., Ltd. Lubricant: erucic acid amide

[Example 1]

Using a twin screw extruder, L-force amide and raw material B1 were mixed in the ratio shown in Table 1 to prepare a master batch. Similarly, prepare a master batch of raw material A1 and talc 39% by mass, blend the raw materials so that the final composition becomes the composition shown in Table 1, and then use a single screw extruder to show in Table 1. The extruder of each layer was controlled so that the layer structure and the thickness of each layer were obtained, and the molten resin was extruded using a three-layer die. When extruding, the outer die lip diameter is 110mm, the inner die lip diameter is 105mm, the lip clearance is 2.5mm, and the tube is extruded from the cooling ring to the molten resin extruded in a tube shape while blowing air at about 25 ° C. Air was injected into the inside to form bubbles. The obtained film was guided to a pinch roll, and the tube-like film was wound up as a flat two film with a winding mouth. Next, after the bubbles were stabilized, the resin extrusion speed, the amount of air injected into the bubbles, and the film winding speed on the pinch roll were finely adjusted to obtain the final thickness films shown in Table 1. The film was slit to a width of 190 mm, and an air cushioning material having a length of 140 mm was prepared using an air cushioning bag making machine 150 manufactured by Tricon Sales Co., Ltd.

[Examples 2 to 4, Comparative Examples 1 to 3]

In the same manner as in Example 1, a film was produced with the composition and layer structure shown in Table 1, and an air shock absorbing material was produced.

[table 1]

The multilayer film with a biodegradable sealant layer of the present invention can be smoothly fed in a packaging (bag making) machine, has an excellent suitability for a high-speed packaging machine, and has a sufficient sealing strength. It can be suitably used for a biodegradable packaging film, a bag-like article, and an air cushioning material that are excellent in holding.

Claims

The scope of the claims

[1] A biodegradable multilayer film having a sealant layer on at least one surface. The sealant layer has a polylactic acid-based resin (A) and a glass transition temperature Tg of 10 ° C or less and a melting point of 70 °. It consists of a mixture of aliphatic polyester-based resin (B) and lubricant (D) at a temperature not lower than C and not higher than 120 ° C. The mixing mass ratio of (A) and (B) is (A) / (B) = 55Z45-13Z87 (D) is 0.01 to 0.5 parts by mass with respect to 100 parts by mass of (A) and (B), and the coefficient of dynamic friction d) of the surface with the sealant layer is 0. A multilayer film with a biodegradable sealant layer that is 15 or more and 0.5 or less.

[2] The polylactic acid-based resin (A) is a substantially non-crystalline polylactic acid-based resin having a molar ratio of L-lactic acid and D-lactic acid constituting the resin of 92 Z8 to 8Z92. The multilayer film with a biodegradable sealant layer according to claim 1.

[3] The multilayer film with a biodegradable sealant layer according to claim 1 or 2, wherein the aliphatic polyester-based resin (B) has a melting point of 70 ° C or higher and 85 ° C or lower.

[4] Further, a crystal nucleating agent (C) is added, and the addition amount of the crystal nucleating agent (C) is 100 parts by mass of the total amount of the polylactic acid-based resin (A) and the aliphatic polyester-based resin (B). 4. The multilayer film with a biodegradable sealant layer according to claim 3, which is 0.5 parts by mass or more and 43 parts by mass or less.

[5] The crystal nucleating agent (C) is an aliphatic polyester-based resin (C2), and the melting point of the aliphatic polyester-based resin (C2) is higher than 85 ° C and lower than 170 ° C. Item 5. The multilayer film with a biodegradable sealant layer according to Item 4.

6. The multilayer film with a biodegradable sealant layer according to claim 5, wherein the aliphatic polyester-based resin (C2) has a molecular weight of 170,000 or less.

7. The multilayer film with a biodegradable sealant layer according to claim 1, wherein the lubricant (D) is a fatty acid amide.

[8] The molar ratio of L-lactic acid and D-lactic acid that make up the fat is 95Z5 ～: L00Z0 polylactic acid based on fat and crystal nucleating agent, and the differential scanning calorimetry at 10 ° CZ min. The melting point (Tm) determined in (1) is 140 ° C to 170 ° C, and the relationship between the heat of fusion (ΔHm) and the heat of crystallization (ΔHe) (ΔΗπι— ΔΗο) is 15j / g-60j / g The multilayer film with a biodegradable sealant layer according to any one of claims 1 to 7, comprising at least one heat-resistant layer.

[9] In any one of claims 1 to 7, the resin constituting each layer is co-extruded and melt-stretched in a molten state under a condition where the stretch ratio is 40 to 200 times in terms of area ratio. The manufacturing method of the multilayer film with a biodegradable sealant layer of description.

[10] A bag-like article using the biodegradable packaging film according to any one of claims 1 to 7.

[11] An air bag cushioning material using the biodegradable packaging film according to any one of claims 1 to 7.