KR101214473B1

KR101214473B1 - Biodegradable polyester oriented film and preparation method thereof

Info

Publication number: KR101214473B1
Application number: KR1020100075946A
Authority: KR
Inventors: 김혜영; 김상일; 김경연
Original assignee: 에스케이씨 주식회사
Priority date: 2010-08-06
Filing date: 2010-08-06
Publication date: 2012-12-24
Also published as: KR20120013749A; WO2012018238A2; WO2012018238A3

Abstract

Biodegradable polyester stretched film formed by copolymerizing lactide with one or more of polycaprolactone and caprolactone monomers having a number average molecular weight (Mn) of 500 to 10,000 has excellent transparency, maximum flexibility, and bleed-out. If not, it can be utilized for various packaging purposes.

Description

Biodegradable polyester oriented film and its manufacturing method {BIODEGRADABLE POLYESTER ORIENTED FILM AND PREPARATION METHOD THEREOF}

The present invention relates to a biodegradable polyester oriented film that can be used as a packaging film and the like and a method for producing the same.

Polyvinyl chloride (PVC), polyethylene (PE), and polypropylene (PP), which are general-purpose plastics derived from petroleum, are currently used in various applications, but when incinerated, they generate harmful substances such as dioxins and There is a problem of accelerating the greenhouse gas effect in the atmosphere by emissions. In addition, since these plastic films are chemically / biologically stable and hardly decompose, they shorten the life of landfills, causing problems with global soil pollution.

In recent years, carbon tax and carbon credit trading systems have been reviewed to raise green growth resources and reduce global greenhouse gases. Accordingly, many researches and developments on biopolymers derived from biomass have been conducted.

In particular, many studies and applications of polylactic acid, a biodegradable aliphatic polyester, have been progressed. In the case of polylactic acid film, mechanical properties and transparency are maintained, but due to its high crystallinity due to molecular structure, it is insufficient in packaging. Its use is limited, and especially in the case of refrigerated and frozen foods to be stored at low temperature, the pinhole resistance is not sufficient, so that the packaging material may rupture during storage and transportation. Many studies have been conducted to solve this problem.

Japanese Laid-Open Patent Publication No. 2003-147098 discloses a biodegradable polylactic acid film having excellent transparency and flexibility, and is characterized in that T-die molding is facilitated by improving roll adhesion of polylactic acid. According to the above document, since the sticking occurs when the D-lactic acid content of the polylactic acid is 4% by weight or more, in order to solve this problem, polylactic acid, poly (butylene adipate / terephthalate) (PBAT) and polycaprolactone 3 Component type blending extrusion is performed and the film is manufactured. Although the above document states that the film thus produced is transparent, an opaque film is obtained because of high haze due to poor compatibility between resins even if the light transmittance is high.

Japanese Laid-Open Patent Publication No. 2004-244553 discloses a flexible low temperature heat-seal laminated film for packaging, in which a ternary copolymer of butanediol / amber acid / caprolactone and an amorphous polylactic acid are laminated. . Further, in order to improve the bursting strength and the blown seal strength of the film disclosed in the patent document, Japanese Laid-Open Patent Publication No. 2004-237473 discloses an aliphatic polyester copolymer of succinic acid / 1,4-butanediol / caprolactone. Aromatic polyester copolymers of PBAT / 1,4-butanediol are disclosed. However, the film is difficult to secure sufficient flexibility.

Thus, there is a need for a new biodegradable film that satisfies transparency and flexibility at the same time.

Japanese Laid-Open Patent Publication No. 2003-147098 (2003.5.21, CI KASEI Co., Ltd.) Japanese Laid-Open Patent Publication No. 2004-244553 (2004.9.2, TOHCELLO) Japanese Laid-Open Patent Publication No. 2004-237473 (2004.8.26, TOHCELLO)

Accordingly, it is an object of the present invention to provide a biodegradable oriented film having sufficient flexibility while maintaining transparency, and a method for producing the same.

In accordance with the above object, the present invention provides a biodegradable polyester oriented film formed by random copolymerization of i) one or more of polycaprolactone and caprolactone monomer having a number average molecular weight (Mn) of 500 to 10,000 and ii) lactide. .

According to the other object, the present invention comprises the steps of (a) random copolymerization of one or more of polycaprolactone and caprolactone monomers of i) number average molecular weight (Mn) 500 to 10,000 and ii) lactide to obtain a copolymer resin; (b) melt extruding the copolymer resin to obtain an unstretched sheet; And (c) stretching and heat-setting the unstretched sheet in at least one of a longitudinal direction and a transverse direction, to provide a method for producing a biodegradable polyester stretched film of the present invention.

The film according to the present invention is made of biodegradable resin, which is environmentally friendly, excellent in transparency, flexibility is maximized, and does not bleed out, and is produced through stretching, and thus has excellent strength and elongation.

Hereinafter, the present invention will be described in more detail.

The biodegradable polyester oriented film of the present invention is obtained by random copolymerization of one or more components of i) polycaprolactone and caprolactone monomers having a number average molecular weight (Mn) of 500 to 10,000 and ii) a lactide component.

Polycaprolactone is obtained by ring-opening a cyclic caprolactone monomer. The polycaprolactone has a long alkyl chain (five CH _{2 s} ) so that sufficient flexibility can be given to the polylactic acid film. Therefore, the film of the present invention is maximized by using the caprolactone monomer or polycaprolactone having a number average molecular weight of 500 to 10,000 as a copolymer.

In the film of the present invention, the component i) is preferably polycaprolactone having a number average molecular weight (Mn) of 500 to 10,000.

It is preferable that the lactide of the said component ii) is L-lactide. When using high-purity L-lactide can further improve the physical properties of the film.

It is preferable that the weight ratios which the said component i) and ii) contain in a film are 80:20-5:95.

It is preferable that the film has a thermal contraction rate of 1 to 75% in the longitudinal direction or the transverse direction at 100 ° C. and hot air conditions of 5 minutes.

The film preferably has an initial elastic modulus of 50 to 400 kgf / mm 2.

It is preferable that the said film is 20% or less of haze.

It is preferable that the said film is 10-300 micrometers in thickness.

Such a biodegradable polyester oriented film of the present invention is copolymerized by random copolymerization of one or more components of (a) i) polycaprolactone and caprolactone monomers having a number average molecular weight (Mn) of 500 to 10,000 and ii) lactide component. Obtaining a resin; (b) melt extruding the copolymer resin to obtain an unstretched sheet; And (c) stretching and heat setting the unstretched sheet in at least one of longitudinal and transverse directions.

In the step (a), the reaction ratio of the components i) and ii) is 80:20 to 5:95 by weight, and the reaction conditions are subjected to random copolymerization at a temperature of 170 to 190 ° C. for 3 to 5 hours under a nitrogen atmosphere. It is preferable.

For example, component i) 5 to 80 parts by weight and component ii) 20 to 95 parts by weight are mixed, and 0.01 to 0.1 parts by weight of tin catalyst (Stannous octoate) and 0.1 to 0.2 parts by weight of SiO ₂ are added as an antiblocking agent. After that, the reaction is carried out at 170 ~ 190 ℃ 3 to 5 hours under a nitrogen atmosphere to remove by-products or unreacted material through a reduced pressure to obtain a random copolymer resin.

The melt extrusion temperature in the step (b) is preferably 180 to 280 ℃.

In addition, in the step (c), the stretching ratio in the longitudinal direction is 2.5 to 3.5 times, the stretching ratio in the transverse direction is 3.5 to 4.5 times, and the heat setting temperature is preferably 80 to 170 ° C.

The invention also provides a packaging comprising a biodegradable polyester oriented film according to the invention.

The film according to the present invention has a high biodegradation rate, which is environmentally friendly and excellent in transparency (light transmittance of 90% or more and haze of 20% or less). In addition, polylactic acid-caprolactone copolymer resin is used to secure sufficient flexibility. As a copolymer, a liquid plasticizer may be used while maximizing flexibility by using a caprolactone monomer and / or polycaprolactone having a number average molecular weight of 500 to 10,000. This can prevent the problem of bleeding out. Moreover, since it is manufactured through extending | stretching, it is excellent in strength and elongation.

Such a film of the present invention is a general packaging film, high-quality packaging film, general label, heat shrink label, agricultural mulching film, overlapping film, paper lamination, nonwoven lamination, disposable gown, wallpaper lamination, flooring lamination It can be used for such purposes.

Example

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are only examples of the present invention and the present invention is not necessarily limited thereto.

The following were prepared as raw materials for use in the following examples:

Caprolactone monomers: Capa ^TM Monomer, Perstorp

-L-lactide: Musashino Chemical Laboratory

-Tin catalyst: Stannous octoate, TEGOKAT

- polycaprolactone (Mn 1,000 ~ 10,000): PL1000 ~ PL10,000, Perstorp Co.

-Polylactic acid resin: 4032D, NatureWorks

Example 1

15 parts by weight of a caprolactone monomer, 85 parts by weight of L-lactide, 0.02 part by weight of tin catalyst, and 0.2 part by weight of SiO ₂ as an antiblocking agent were mixed. The reaction was carried out at 190 ° C. for 5 hours under a nitrogen atmosphere, and then by-products or unreacted materials were removed under reduced pressure to obtain a random copolymer resin of Mn 100,000.

The obtained copolymer resin was melt-extruded at 200 ° C. and brought into close contact with a casting roll at 10 ° C., stretched at 85 ° C. in 3.0 times in the longitudinal direction, and stretched at 105 ° C. in 4.0 times in the transverse direction to obtain a sheet. This was heat-set at 100 degreeC, and the polyester stretched film of 20 micrometers in thickness was obtained.

Example 2

The same procedure as in Example 1 was carried out except that the heat setting temperature was 160 ° C., thereby obtaining a polyester stretched film having a thickness of 20 μm.

Example 3

25 parts by weight of polycaprolactone having a number average molecular weight (Mn) of 1,000, 75 parts by weight of L-lactide, 0.02 parts by weight of tin catalyst, and 0.2 parts by weight of SiO ₂ as an antiblocking agent were mixed. The reaction was carried out at 180 ° C. for 5 hours under a nitrogen atmosphere to remove by-products or unreacted materials under reduced pressure to obtain a random copolymer resin of Mn 90,000.

The obtained resin was melt-extruded at 210 ° C. and brought into close contact with a casting roll at 9 ° C., stretched at 80 ° C. at 3.0 times in the longitudinal direction, and stretched at 100 ° C. at 4.0 times in the transverse direction to obtain a sheet. This was heat-set at 105 degreeC, and the polyester stretched film of 20 micrometers in thickness was obtained.

Example 4

A polyester stretched film having a thickness of 20 μm was obtained in the same manner as in Example 3, except that the heat setting temperature was set to 150 ° C.

Example 5

20 parts by weight of polycaprolactone having a number average molecular weight (Mn) of 3,000, 80 parts by weight of L-lactide, 0.025 parts by weight of tin catalyst, and 0.2 parts by weight of SiO ₂ as an antiblocking agent were mixed. The reaction was carried out at 200 ° C. for 6 hours under nitrogen atmosphere to remove by-products or unreacted materials under reduced pressure to obtain a random copolymer resin of Mn 110,000.

The obtained resin was melt-extruded at 200 ° C. and brought into close contact with a casting roll at 15 ° C., stretched at 77 ° C. at 3.0 times in the longitudinal direction, and stretched at 100 ° C. at 3.8 times in the transverse direction to obtain a sheet. This was heat-set at 95 degreeC, and the polyester stretched film of 20 micrometers in thickness was obtained.

Example 6

23 parts by weight of polycaprolactone with a number average molecular weight (Mn) of 7,000, 77 parts by weight of L-lactide, 0.03 parts by weight of tin catalyst, and 0.2 parts by weight of SiO ₂ as an antiblocking agent were mixed. The reaction was carried out at 200 ° C. for 6 hours under nitrogen atmosphere to remove by-products or unreacted materials under reduced pressure, thereby obtaining a random copolymer resin of Mn 95,000.

The obtained resin was melt-extruded at 180 ° C. and brought into close contact with a casting roll at 13 ° C., stretched at 75 ° C. at 3.0 times in the longitudinal direction, and stretched at 96 ° C. at 3.7 times in the transverse direction to obtain a sheet. This was heat-set at 80 degreeC, and the polyester stretched film of 20 micrometers in thickness was obtained.

Example 7

7 parts by weight of a caprolactone monomer, 10 parts by weight of polycaprolactone having a number average molecular weight (Mn), 83 parts by weight of L-lactide, 0.03 parts by weight of tin catalyst, and 0.2 parts by weight of SiO ₂ as an antiblocking agent were mixed. The reaction was carried out at 190 ° C. for 5 hours under nitrogen atmosphere to remove by-products or unreacted materials under reduced pressure, thereby obtaining a random copolymer resin of Mn 80,000.

The obtained resin was melt-extruded at 190 ° C. and brought into close contact with a casting roll at 12 ° C., stretched at 85 ° C. in 3.0 times in the longitudinal direction, and stretched at 100 ° C. in 4.0 times in the transverse direction to obtain a sheet. This was heat-set at 85 degreeC, and the polyester stretched film of 20 micrometers in thickness was obtained.

Comparative Example 1

15 parts by weight of polyethylene glycol, 85 parts by weight of L-lactide, 0.004 parts by weight of tin catalyst, and 0.1 part by weight of SiO ₂ as an antiblocking agent were mixed. The reaction was carried out at 170 ° C. for 6 hours under a nitrogen atmosphere to remove by-products or unreacted materials under reduced pressure to obtain a random copolymer resin of Mn 80,000.

The obtained resin was melt-extruded at 190 ° C. and brought into close contact with a casting roll at 15 ° C., stretched at 90 ° C. at 3.0 times in the longitudinal direction, and stretched at 110 ° C. at 4.0 times in the transverse direction to obtain a sheet. This was heat-set at 160 degreeC, and the polyester stretched film of 20 micrometers in thickness was obtained.

Comparative Example 2

In a repeating unit, 14 parts by weight of a polyol having three -CH _2- , 86 parts by weight of L-lactide, 0.01 part by weight of a tin catalyst, and 0.2 part by weight of SiO ₂ were mixed with an antiblocking agent. The reaction was carried out at 190 ℃ for 7 hours under a nitrogen atmosphere to remove by-products or unreacted materials through a reduced pressure, to obtain a random copolymer resin of Mn 70,000.

The obtained resin was melt-extruded at 200 ° C. and brought into close contact with a casting roll at 12 ° C., stretched at 85 ° C. in 3.0 times in the longitudinal direction, and stretched at 105 ° C. in 4.0 times in the transverse direction to obtain a sheet. This was heat-fixed at 150 degreeC, and the polyester stretched film of 20 micrometers in thickness was obtained.

Comparative Example 3

Polylactic acid resin (Tm 170 ℃, Tg 65 ℃) was dried by hot air dryer at 100 ℃ 3 hours to remove moisture. 90 parts by weight of the dried resin, 10 parts by weight of caprolactone monomer, and 0.1 parts by weight of SiO ₂ as an antiblocking agent were uniformly compounded using a twin screw at 200 ° C.

The obtained resin was melt-extruded at 190 ° C. and brought into close contact with a casting roll at 13 ° C., stretched at 75 ° C. at 3.0 times in the longitudinal direction, and stretched at 95 ° C. at 4.0 times in the transverse direction to obtain a sheet. This was heat-fixed at 150 degreeC, and the polyester stretched film of 20 micrometers in thickness was obtained.

The composition and manufacturing process of the film according to each Example and Comparative Example are summarized in Table 1 below.

Test Example

The physical properties of the films prepared in Examples and Comparative Examples were evaluated in the following manner, and summarized in Table 1 below.

(1) Molecular weight measurement of copolymer resin

The molecular weight of the resin was measured using an ELSD detector after dissolving 0.003 g of a sample in a solvent (THF; tetrahydrofuran) using a GPC measuring instrument (Waters, USA) and injecting at 1 mL / min at room temperature.

(2) the composition of the film

The film was dissolved in a solvent (a 4: 1 mixed solution of chloroform and trifluoroacetic acid substituted with deuterium), and the area ratio of each characteristic peak obtained by measuring by H-NMR (JSM-LA300, Jeol, Japan) was used. Calculated by mole% to obtain.

(3) bleed out

The film was cut into 20 cm x 20 cm and placed in a 150 ° C. hot air oven for 2 hours, and evaluated according to the following criteria.

O: The film surface is low in lubricity and the slipperiness between films is low

X: The film surface is large in lubricity, and the slipperiness between films is large.

(4) initial elastic modulus, strength and elongation

According to ASTM D 882, measured using a universal testing machine (UTM 4206-001, INSTRON Co., Ltd.), the film was cut to about 100mm in length and 15mm in width and then mounted so that the intervertebral spacing was 50mm and the tensile speed was 200mm / min. Experiments were conducted to obtain the initial modulus of elasticity (kgf / mm 2) and the strength and elongation values calculated by the program embedded in the installation. Lower initial elastic modulus provides greater flexibility.

(5) Haze

Measured with haze meter (SEP-H, Nihon Semitsu Kogaku, Japan) and C-light source was used.

(6) Pinhole resistance

Using Gelbo Flex (Gelbo Flex, Gelbo, USA) (Composition-Sample mounting table: 165mm, Sample mounting diameter: 88mm, Reciprocating movement distance: 125mm), Rotation and reciprocation at a rotation angle of 450 degrees at room temperature for about 10 minutes After 450 times, the film was laid flat on white paper. After applying a conventional solvent-based nitroglycerin (NC) ink using a doctor blade on it, the ink spot appearing on the white paper was counted as the number of pinholes of the sample, and the average value obtained by repeating this measurement three times per sample was The number of pinholes was compared.

(7) thermal shrinkage of film

After the sample was cut into a length of 200 mm and a width of 15 mm in the direction to be measured and held for 5 minutes in an air circulation oven maintained at 100 ° C., the length of the film was measured to calculate shrinkage in the longitudinal and transverse directions according to the following equation. .

Shrinkage (%) = (length before shrink x length after shrink) / length before shrink x 100

As can be seen in Table 1, it can be seen that the film of Examples 1 to 7 according to the present invention is superior in the characteristics of the bleed-out, haze, pinhole resistance, elastic modulus, heat shrinkage, etc. compared to the film of Comparative Examples 1 to 3 have.

Particularly, in Examples 3 to 7 in which the raw material resin was copolymerized using polycaprolactone having a molecular weight of 500 to 10,000, more free volume was created so that segments were more actively moved between the polylactic acid chains. By ensuring that the flexibility is maximized.

In addition, in Examples 1, 3, and 5 to 7, the heat-setting temperature was lowered to lower the heat-fixing temperature so as not to firmly fix the positions of the polymer chains, thereby obtaining a film having a high thermal contraction rate, which can be used as an overlapping film. In Examples 2 and 4, the heat setting temperature was increased to obtain a film having a low heat shrinkage rate, which can be used as a general packaging material.

On the other hand, Comparative Examples 1 and 2 For a copolymer, each -CH ₂ - is the presence of two polyethylene glycol (PEG) to the -CH ₂ - were to use the polyol present in three, these CH ₂ that the presence of 5 It was evaluated to be less flexible than the example using caprolactone.

In addition, in Comparative Example 3, the caprolactone monomer was compounded / blended with polylactic acid and extruded, but a bleed-out phenomenon in which the caprolactone monomer having a small molecular weight leaked out of the sheet occurred.

In the case of strength and elongation, both the films of Examples and Comparative Examples were excellently stretched through stretching.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, It is to be understood that the invention may be practiced within the scope of the appended claims.

Claims

i) polycaprolactone having a number average molecular weight (Mn) of 500 to 10,000 or a mixture of said polycaprolactone and caprolactone monomers; And
ii) A biodegradable polyester oriented film obtained by random copolymerization of lactide.

The method of claim 1,
Component i) contained in the film is a polycaprolactone having a number average molecular weight (Mn) of 500 to 10,000, a biodegradable polyester oriented film.

The method of claim 1,
The lactide is L-lactide, characterized in that the biodegradable polyester stretched film.

The method of claim 1,
A weight ratio of said components i) and ii) contained in the film is 80:20 to 5:95, The biodegradable polyester stretched film.

The method of claim 1,
The film is a biodegradable polyester stretched film, characterized in that the heat shrinkage in the longitudinal direction or transverse direction at 100 ℃ and hot air conditions of 5 minutes is 1 to 75%.

The method of claim 1,
The film has an initial elastic modulus of 50 to 400 kgf / mm 2, biodegradable polyester stretched film.

The method of claim 1,
The film has a haze of 20% or less, biodegradable polyester stretched film.

The method of claim 1,
The film has a thickness of 10 to 300 ㎛, Biodegradable polyester stretched film.

i) polycaprolactone having a number average molecular weight (Mn) of 500 to 10,000, or a mixture of said polycaprolactone and a caprolactone monomer; And ii) random copolymerization of lactide to obtain a copolymer resin.
(b) melt extruding the copolymer resin to obtain an unstretched sheet; And
(c) stretching and heat setting the unstretched sheet in at least one of longitudinal and transverse directions, wherein the biodegradable polyester oriented film of claim 1 is prepared.

10. The method of claim 9,
In the step (a), the reaction ratio of components i) and ii) is 80:20 to 5:95 by weight, and the reaction conditions are 3 to 5 hours random copolymerization reaction at a temperature of 170 to 190 ° C. under a nitrogen atmosphere. How to feature.

10. The method of claim 9,
Melt extrusion temperature in the step (b) is characterized in that 180 to 280 ℃.

10. The method of claim 9,
In the step (c), the draw ratio in the longitudinal direction is 2.5 to 3.5 times, the draw ratio in the transverse direction is 3.5 to 4.5 times.

10. The method of claim 9,
The heat setting temperature of step (c) is characterized in that 80 to 170 ℃.

A packaging material comprising the biodegradable polyester oriented film of claim 1.