KR102437300B1 - Biodegradable and heat shrinkable film - Google Patents

Abstract

The present invention relates to a biodegradable and heat-shrinkable film. The biodegradable and heat-shrinkable film comprises 30-70 wt% of polybutylene succinate (PBS) having an average molecular weight of 140,000-280,000, and 30-70 wt% of polybutylene adipate terephthalate (PBAT) having an average molecular weight of 140,000-280,000. Based on 100 wt% of a mixture of the polybutylene succinate and the polybutylene adipate terephthalate, 1-3 wt% of a slip agent, 1-3 wt% of an anti-blocking agent, and 1-3 wt% of a compatibilizer are further included. The biodegradable and heat-shrinkable film is biodegraded by microorganisms in 3-4 weeks in 95% in a natural state of being buried in soil, and is composed of only biodegradable compounds without using synthetic resins such as polyethylene terephthalate (PET), thereby being completely biodegradable by metabolism of the microorganisms even when buried in soil. In addition, the biodegradable and heat-shrinkable film can be used as a general-purpose bundling film regardless of a weight and size of a packaging material. The biodegradable and heat-shrinkable film has good elongation and flexibility while having excellent mechanical properties by properly mixing polybutylene succinate and polybutylene adipate terephthalate. Moreover, since a difference in melting temperature between polybutylene succinate and polybutylene adipate terephthalate is not large, a process time is shortened.

Description

Biodegradable heat shrinkable film

The present invention relates to a biodegradable heat-shrinkable film, and more particularly, to a biodegradable compound of polybutylene succinate (PBS) and polybutylene adipate terephthalate (PBAT). It relates to a biodegradable heat-shrinkable film with excellent mechanical properties and heat shrinkage in both the longitudinal (MD) and transverse (TD) directions, which is biodegraded slowly and completely after being biodegraded to 95% in about 3 to 4 weeks.

Bottled water, beverages, beer, or dairy products (milk, soymilk, yogurt) sold in large marts and supermarkets are stored in PET bottles, aluminum cans, or plastic containers. They are often sold in bundles of In general, heat-shrinkable film is a film having a property of shrinking when heated, covering or surrounding an article to be packaged, and then passing it through a hot-air tunnel or the like to shrink by heat.

Looking at the prior art for the heat-shrinkable film,

Republic of Korea Patent Publication No. 10-0554978 biodegradable heat-shrinkable film (March 03, 2006) contains 30-70% by weight of polylactic acid (PLA) and 25-60% by weight of neopentyl glycol copolymerized polyester (N-PET). As a resin composition composed of 0 to 10% by weight of polyethylene terephthalate (PET), the biodegradability is 20% or more, and the thermal contraction rate in hot water at 90°C is 30% in at least one direction of the film length direction and the width direction It consists of more than

The heat-shrinkable film of the prior art has a problem in that it is not completely decomposed by microorganisms when discarded by polyethylene terephthalate (PET), and when it accumulates in the soil, environmental pollution is caused later.

In addition, the prior art has a problem in that the thermal contraction rate in the longitudinal direction (MD) is significantly lowered by the polylactic acid (PLA).

In addition, the prior art has a problem in that the productivity is lowered due to a large difference in melting temperature between polylactic acid (PLA) and polyester or polyethylene terephthalate (PET).

The present invention has been devised to solve the problems of the prior art, and has an average molecular weight of 140,000 to 280,000 polybutylene succinate (PBS) 30 to 70% by weight and polybutylene adipate having an average molecular weight of 140,000 to 280,000 Terephthalate (PBAT) is composed of a mixture of 30-70 wt% biodegradable compounds and is biodegraded to 95% by microorganisms in the natural state buried in the soil for 3-4 weeks and then slowly completely biodegraded, causing environmental pollution It is to provide a biodegradable heat-shrinkable film having excellent mechanical properties and heat shrinkage rate and excellent productivity in both the longitudinal direction (MD) and the transverse direction (TD).

In the present invention, in the biodegradable heat-shrinkable film, the biodegradable heat-shrinkable film is composed of 30 to 70% by weight of polybutylene succinate (PBS) and 30 to 70% by weight of polybutylene adipate terephthalate (PBAT).

In the present invention, the polybutylene succinate (PBS) and polybutylene adipate terephthalate (PBAT) each have an average molecular weight of 140,000 to 280,000.

In addition, in the present invention, 1 to 3% by weight of the slip agent is further included based on 100% by weight of the polybutylene succinate (PBS) and polybutylene adipate terephthalate (PBAT) mixture.

In addition, in the present invention, 1 to 3% by weight of the antiblocking agent (ab) is further included based on 100% by weight of the polybutylene succinate (PBS) and polybutylene adipate terephthalate (PBAT) mixture.

In addition, in the present invention, 1 to 3% by weight of a compatibilizer is further included based on 100% by weight of the mixture of polybutylene succinate (PBS) and polybutylene adipate terephthalate (PBAT).

The present invention is composed only of biodegradable compounds without using any synthetic resins such as polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE: polyethylene), etc. It has a biodegradable effect.

In addition, the present invention has an effect that can be used as a universal film for bundling regardless of the weight and size of the packaging material.

In addition, the present invention has an effect of good elongation and flexibility while having excellent mechanical properties by appropriately mixing polybutylene succinate (PBS) and polybutylene adipate terephthalate (PBAT).

In addition, the present invention has the effect of shortening the process time because the melting temperature difference between polybutylene succinate (PBS) and polybutylene adipate terephthalate (PBAT) is not large.

In addition, since the present invention is completely biodegradable and does not need to be collected after use, labor is reduced or incineration is not required, thereby reducing incineration costs.

Figure 1: Biodegradation photos for each period of the present invention.
Figure 2: Test report of the Korea Research Institute of Chemical Convergence (KTR) for the present invention 1.
Figure 3: Test report of the Korea Research Institute of Chemical Convergence (KTR) for the present invention 2.
Figure 4: Fourier transform infrared (FTIR) absorption spectrum for the present invention.
Figure 5: Nuclear magnetic resonance (NMR) spectrum for the present invention.
Figure 6: Thermogravimetric analysis (TGA) spectrum for the present invention.

The biodegradable heat-shrinkable film of the present invention is composed of a biodegradable compound of polybutylene succinate (PBS: PolyButylene Succinate) and polybutylene adipate terephthalate (PBAT: PolyButylene co-Adipate co-Terepthalate). It is completely decomposed and can prevent environmental pollution even during incineration.

The polybutylene succinate (PBS) uses butanediol (1,4-butanediol) as aliphatic glycols and succinic acid as aliphatic dicarboxylic acids as raw materials, It is a type of biodegradable polyester-based resin as a polymer obtained through a polycondensation reaction.

The polybutylene succinate (PBS) has excellent structural strength, but has a low elongation rate due to high crystallinity, that is, it does not stretch well, and is hydro-biodegradable and a hydrolysis mechanism occurring in an ester linkage group. It begins to biodegrade through the natural environment and is further decomposed by microorganisms in the natural environment to completely decompose into carbon dioxide and water with excellent biodegradability.

As the polybutylene succinate (PBS), commercially available ones such as BIONOLLE of Showa Polymer of Japan, G4560 of Lotte Fine Chemical Co., Ltd. of Korea, and G4560-J of S-EnPol may be used.

The polybutylene adipate terephthalate (PBAT) contains butanediol (1,4-butanediol) as aliphatic glycols, adipic acid as an aliphatic component as dicarboxylic acids, and aromatic It becomes an aliphatic/aromatic co-polyester using dimethyl terephthalate (DMT) as a raw material.

The polybutylene adipate terephthalate (PBAT) has high flexibility and excellent processability and toughness, so it can modify the properties of the resin when mixed with other polymers. Since a significant portion of the amorphous (non-crystalline) region exists in It has low strength, slow solidification rate, and excellent biodegradability by being further decomposed by microorganisms in the natural environment. 130°C.

The polybutylene adipate terephthalate (PBAT) is PBG7070 of Lotte Fine Chemical Co., Ltd. of Korea, 7070 of S-Enpol, ECOPLEX of BASF, Biomax of DuPont of France, Origo-Bi of Novamont, Italy, Commercially available ones such as Easter Bio of Eastman Chemical in the United States can be used.

The biodegradable heat-shrinkable film of the present invention is composed of only biodegradable compounds by mixing polybutylene succinate (PBS) and polybutylene adipate terephthalate (PBAT), so that the polymer is low molecular weight and the microorganisms can be completely digested even when buried in the soil. When it is decomposed to a suitable size, it is completely biodegraded by the metabolism of microorganisms, and soil microorganisms are activated and there is no harm to the soil ecosystem.

The biodegradable heat-shrinkable film of the present invention is completely biodegradable and does not need to be collected after use, so labor is reduced or incineration costs are reduced, and polybutylene succinate (PBS) and polybutylene adipate terephthalate. Since the difference in melting temperature, that is, melting point, of phthalate (PBAT) is not large, the process time is shortened.

The melt resin and density of the composition for the biodegradable heat-shrinkable film of the present invention are shown in Table 1 below.

melt index
(MI: g/10min) density
(g/ml) note Polybutylene Succinate (PBS) 0.5~5.0 1.20~1.25 Polybutylene Adipate Terephthalate (PBAT) 0.5~5.0 1.20~1.25

The melt index (MI) was measured at 190° C. and 2.16 kg under the conditions of ASTM D1238, and the density was measured in a Density Gradient Column according to the ASTM D1505 method.

The polybutylene succinate (PBS) has a melt index (MI) If it is 0.5 g/10 min or less and the density is 1.20 g/ml or less, uniform shrinkage cannot be obtained. this is reinforced When the melt index (MI) of the polybutylene adipate terephthalate (PBAT) is 0.5 g/10 min or less and the density is 1.20 g/ml or less, the tensile strength is lowered, and the melt index (MI) is 5.0 g/10 min or more And when the density is 1.25 g/ml or more, the elongation is lowered. That is, as the polybutylene succinate (PBS) and polybutylene adipate terephthalate (PBAT) have a melt index (MI) in this range, the biodegradable heat-shrinkable film exhibits superior processability, etc., and provides excellent flexibility. To this end, the polybutylene succinate (PBS) repeating unit or the polybutylene adipate terephthalate (PBAT) repeating unit may be included in an amount of 60 mol% or more, or 70 mol% or more, or 90 to 100 mol%.

The polybutylene succinate (PBS) and polybutylene adipate terephthalate (PBAT) have an average molecular weight of 140,000 to 280,000. Compatibility between polybutylene succinate (PBS) and polybutylene adipate terephthalate (PBAT) as the polybutylene succinate (PBS) and polybutylene adipate terephthalate (PBAT) have this molecular weight range And processability becomes more excellent, and the biodegradable heat-shrinkable film exhibits improved mechanical properties and heat-shrinkability according to a relatively high molecular weight.

The biodegradable heat-shrinkable film is composed of a mixture of 30 to 70% by weight of polybutylene succinate (PBS) and 30 to 70% by weight of polybutylene adipate terephthalate (PBAT), preferably polybutylene succinate (PBS) 40 to 60% by weight and 40 to 60% by weight of polybutylene adipate terephthalate (PBAT). In general, biodegradable heat-shrinkable films have been disclosed in which polyester or polyethylene terephthalat or polybutylene succinate (PBS) is mixed with polylactide resin, but polybutylene succinate (PBS) ) and polybutylene adipate terephthalate (PBAT) have not been mixed.

Polybutylene succinate (PBS) used in the biodegradable heat-shrinkable film of the present invention can be obtained by polycondensation of 1,4-butanediol and succinic acid according to a known general method, and polybutylene adipate terephthalate (PBAT) is known Since it can be obtained by polycondensation of 1,4-butanediol, adipic acid and terephthalic acid according to a general method, one directly synthesized by this general method may be used, or one that has already been commercialized may be obtained and used.

The biodegradable heat-shrinkable film is mixed in an appropriate ratio using different physical properties of polybutylene succinate (PBS) and polybutylene adipate terephthalate (PBAT) to secure heat shrinkage, mechanical strength, flexibility, and processability When the biodegradable heat-shrinkable film is composed of only polybutylene succinate (PBS), it has excellent heat shrinkage and mechanical strength, but lacks ductility, so that tearing occurs in the formation, that is, in the longitudinal direction (MD), and poly In the case of being composed only of butylene adipate terephthalate (PBAT), the ductility is excellent, but the mechanical strength is insufficient. When an appropriate amount of the polybutylene succinate (PBS) and polybutylene adipate terephthalate (PBAT) is melt-kneaded, the toughness, strength and shrinkage of the film are increased, no formation occurs, and the flexibility of the film is also increased. It also maintains biodegradability.

When the polybutylene succinate (PBS) is 30% by weight or less, there is no formation, but the contraction in the longitudinal direction, that is, the longitudinal direction (MD) is insufficient, and when it is 70% by weight or more, heat shrinkage is good but formation occurs, and polybutylene succinate (PBS) is formed. When the amount of lene adipate terephthalate (PBAT) is 30% by weight or less, the flexibility is reduced, and when it is 70% by weight or more, the flexibility is good, but the mechanical properties are low and the transparency is deteriorated.

The biodegradable heat-shrinkable film has an acid value of 1.1 to 1.5. When the biodegradable heat-shrinkable film is buried in the soil, the biodegradable heat-shrinkable film is biodegraded to about 95% in about 4 weeks when the acid value is 1.1 and then completely biodegraded, and when the acid value is 1.5, after about 3 weeks After 95% biodegradation, it is gradually completely biodegraded.

If the biodegradable heat-shrinkable film is unintentionally dropped on a crop cultivation area such as a field after use, the remaining 5% after the biodegradable heat-shrinkable film is about 95% biodegradable, taking into consideration the period and degree of decomposition that does not affect the growth of crops The acid value was determined in consideration of the unreasonable point that the acid value must be unnecessarily high in order to rapidly biodegrade the remaining 5% because the biodegradation of

The acid value is the amount of the acid component in the biodegradable heat-shrinkable film, and the amount of potassium hydroxide (KOH: Potassium Hydroxide) required to neutralize the acid component of 1 g of the sample is expressed in mg. It is used as a catalyst for calcium carbonate (CC). The acid value is controlled by the addition of potassium hydroxide (KOH), which is used, and in general, the lower the acid value, the better the hydrolysis stability, and the acid value is determined by an alkali catalyst. The potassium hydroxide (KOH) is a white solid of an inorganic compound, has a strong property of absorbing moisture and carbon dioxide, has a high solubility of potassium carbonate produced when absorbing moisture and carbon dioxide, and has 1,2, and tetrahydrate salts, and the melting point is 143°C, 35.5°C and -32.7°C, respectively, and the transition temperatures therebetween are 32.5°C and -33°C.

As the alkali catalyst, in addition to potassium hydroxide (KOH), sodium hydroxide (Sodium Hydroxide), calcium hydroxide (Calcium Hydroxide), sodium carbonate anhydrous (Sodium Carbonate Anhydrous) and potassium carbonate anhydrous (Potassium Carbonate Anhydrous), etc. may be used, and these may be used alone or in two It is determined by the mixture of more than one species, so that it is easy to control the acid value.

In order to secure excellent shrinkability of the biodegradable heat-shrinkable film, polybutylene succinate (PBS) repeating unit or polybutylene adipate terephthalate (PBAT) repeating unit is polybutylene succinate at 40-80 mol% (mole%). When the sodium content (PBS) is 40 mol% or less, the shrinkage is not good when it is 80 mol% or more, and when the polybutylene adipate terephthalate (PBAT) is 40 mol% or less, the toughness decreases, and when it is 80 mol% or more has an increased melting point.

The biodegradable heat-shrinkable film is composed of a thickness of 10 ~ 130㎛. When the thickness of the biodegradable heat-shrinkable film is 10㎛ or less, six plastic containers filled with dairy products are bundled into one, and the strength required for storage and transport cannot be maintained. 6 PET bottles are bundled together to maintain sufficient strength for storage and transportation, while making them thicker than necessary. The present invention can be used as a universal film for bundling regardless of the weight and size of the packaging material.

The biodegradable heat-shrinkable film may further include additives such as a slip agent, an anti-blocking agent (ab), and a compatibilizer to improve productivity within a range that does not impair biodegradation and heat shrinkage. 1 to 3% by weight of the slip agent is further included based on 100% by weight of the polybutylene succinate (PBS) and polybutylene adipate terephthalate (PBAT) mixture. When the slip agent is 2 wt% or less, it is difficult to improve the slip property because the friction coefficient cannot be dropped. The slip agent strengthens the slip property when forming the biodegradable heat-shrinkable film to prevent tearing of the biodegradable heat-shrinkable film and to have a uniform thickness and to improve productivity compared to the general heat-shrinkable film.

The slip agent is an olefin wax, hydroxy ethyl amine (oxy ethyl follow amine), polyoxy ethylene alkyl amine (polyoxy ethylene alkyl amine), lauric diethyl amide (lauric diethyl amide), stearic acid monoglyceride (stearic) acid monoglyceride), glyceryl stearate, and fatty acid amide (fatty acid amide).

The fatty acid amide is a compound having a neutral structure in which a hydroxyl group is substituted with an amino structure, erucamide, oleamide, behenamide, stearamide, stearyl stearamide, stearyl erucamide, oleylpalmityl amide, and the like.

In general, the film has a high coefficient of friction or is sometimes stuck to each other due to the blocking of the inner film surface sticking to each other at the nip-roll during film forming, which sometimes interferes with the operation. To prevent this phenomenon, the biodegradation of the present invention Anti-blocking agent (ab: antiblocking agent) is added to the heat-shrinkable film to reduce blocking.

Based on 100% by weight of the polybutylene succinate (PBS) and polybutylene adipate terephthalate (PBAT) mixture, 1 to 3% by weight of the antiblocking agent (ab) is further included, and the antiblocking agent (ab) is 1% by weight If it is less than, it is difficult to secure the printability and anti-blocking properties of the product, and if it is 3% by weight or more, it is difficult to obtain good slip properties because protrusions are formed on the surface. The particle size of the anti-blocking agent (ab) is 2.0 to 5.0 μm, and if the particles are in this range, a biodegradable heat-shrinkable film with excellent scratch resistance can be obtained.

The anti-blocking agent (ab) is contained in the matrix of polybutylene succinate (PBS) and polybutylene adipate terephthalate (PBAT) as spherical inorganic particles, etc. In addition, since the anti-blocking agent (ab) serves to hold the low-molecular material so that the low-molecular material does not come off the surface of the film, it is possible to minimize the migration of the soluble material and prevent the occurrence of bubbles in the manufacturing process.

The anti-blocking agent (ab) is calcium carbonate, amorphous silica, diatomaceous earth, kaolin, talc, talc, magnesium carbonate, barium carbonate, calcium sulfate, barium sulfate, lithium phosphate, calcium phosphate, magnesium phosphate, aluminum oxide, lithium fluoride, dicarboxylic acid of calcium, barium, zinc or manganese salt, carbon black, titanium dioxide, kaolin, cross-linked polystyrene particles, cross-linked acrylate particles, silicon beads or Teflon beads are composed of any one or more.

Based on 100 wt% of the polybutylene succinate (PBS) and polybutylene adipate terephthalate (PBAT) mixture, 1-3 wt% of a compatibilizer is further included, and when the compatibilizing agent is 1 wt% or less, polybutylene Since compatibility between succinate (PBS) and polybutylene adipate terephthalate (PBAT) is not sufficiently secured, the effect of improving film processability and physical properties is insignificant. MI: Melt Index) is lowered, so that a gel may occur during film processing or a problem of poor processability may occur.

The compatibilizer is a component that improves the bonding strength between polybutylene succinate (PBS) and polybutylene adipate terephthalate (PBAT), and is a compound of polybutylene succinate (PBS) and polybutylene adipate terephthalate (PBAT). It improves the tensile and tear strength after film production by increasing dispersibility and stability. The compatibilizer is composed of any one of a graft copolymer obtained by grafting maleic anhydride (MA) onto a biodegradable polymer, an epoxidized oil, and a polyfunctional compound having an epoxy group.

The graft copolymer is a graft copolymer in which maleic anhydride (MA) is grafted onto at least one biodegradable polymer selected from the group consisting of polybutylene succinate (PBS) and polybutylene adipate terephthalate (PBAT). may be, preferably polybutylene adipate terephthalate-maleic anhydride (poly(butylene adipate-co-terephthalate)-Maleic anhydride, PBAT-MA). The graft copolymer may be prepared by a known technique, for example, after adding maleic anhydride (MA) to the polybutylene succinate (PBS) or polybutylene adipate terephthalate (PBAT), dicumyl peroxide (dicumyl peroxide) may be prepared using a twin-screw extruder by adding an initiator.

The polybutylene succinate (PBS) uses the product name G4560 of Korea Lotte Fine Chemical Co., Ltd., and the polybutylene adipate terephthalate (PBAT) uses the product name PBG7070 of Korea Lotte Fine Chemical Co., Ltd. to implement the biodegradable heat-shrinkable film of the present invention According to the example, physical properties and biodegradability were measured and evaluated in the following way.

(1) acid value

After dissolving 0.5 g of the resin in 20 ml of chloroform, the solution to which ethanol was added was titrated with 0.1N potassium hydroxide (KOH) in an autotitrator to calculate the acid value.

(2) Tensile strength, tear strength and elongation

Tensile strength (kgf/cm2), tear strength (kgf/cm), and elongation (%) at break of the sample were measured according to the 7.6 tensile strength and elongation test method of KS M 3503, and longitudinal (MD) and transverse directions After each measurement for (TD), the lowest value was taken.

(3) shrinkage

It was carried out according to the test method specified for KS A1511 shrink packaging film, and 100 mm * 100 mm square samples parallel to the longitudinal direction (MD) of one side of the film were taken from the manufactured heat-blocking shrink film 10, After immersing in a bath of ethylene glycol solution for 20 seconds, it was taken out and cooled to room temperature for 5 seconds to measure the lengths in the longitudinal (MD) and transverse (TD) directions, and the shrinkage rate was calculated by the following formula.

Shrinkage (%) = 100-(Lo-Lt)/Lo

Lo: Length before contraction.

Lt: length after shrinkage.

(4) Appearance of film after shrinkage

Six 1,8L PET bottles filled with bottled water were packaged in a bundle and heat-shrinked in an air oven at 150°C for 30 seconds. If it is good, if it is less than 5, it is indicated as normal, and if it exceeds 5, it is indicated as bad. In addition, the number of appearance defects such as wrinkles, curled upper and lower ends, and discoloration were identified.

(5) biodegradability

KS M 3100-1 The amount of carbon dioxide generated in the standard sample (cellulose) and the test sample was measured and evaluated by the aerobic biodegradability measurement method of plastics under composting conditions.

Biodegradability (%) = (amount of carbon dioxide generated / theoretical amount of carbon dioxide)*100

The biodegradable heat-shrinkable film of the present invention uses a film forming machine (Daeryun Machinery Co., Ltd., model: 50mm HD/PE FILM M/C) to set the temperature condition of the extruder in the range of 114 to 126 ° C. With appropriate adjustment, the extrusion speed was 500 rpm, the raw material input speed was 100 rpm, and the roll speed was 200 rpm, so that the thickness was 80 μm.

The acid value and composition status of Examples of the present invention are shown in Table 2 below.

division Example 1 Example 2 Example 3 Example 4 Example 5 mountain autumn 1.51 1.49 1.50 1.50 1.49 PBS 30 40 50 60 70 PBAT 70 60 50 40 30

In Examples 1 to 5, the acid value was simplified in order to reduce the variables of measurement and evaluation, and additives such as a slip agent, an anti-blocking agent (ab), and a compatibilizer were not included.

The physical properties and appearance evaluation results according to the embodiment of the present invention are shown in Table 3 below.

comparative example Example 1 Example 2 Example 3 Example 4 Example 5 The tensile strength
(M/mm) Longitudinal (MD) 51 50 53 54 57 61 Transverse direction (TD) 46 47 49 51 53 57 elongation
(%) Longitudinal (MD) 623 665 656 642 635 621 Transverse direction (TD) 641 703 696 686 679 664 tear strength
(N/mm) Longitudinal (MD) 232 281 269 258 250 238 Transverse direction (TD) 260 308 291 279 273 261 shrinkage
(%) Longitudinal (MD) 72 73 74 76 77 80 Transverse direction (TD) 17 17 19 20 22 25 film appearance Good Good Good Good Good Good

The comparative example is a polyethylene-based heat-blocking shrink film manufactured by the present applicant while being used for integrated packaging in PET beverage bottles.

The above Example 3 is the same as the sample (TAK-072599 biodegradable shrink film) requested by the applicant to the Korea Testing and Research Institute for testing, and the evaluation of the physical properties thereof cited the test results of the Korea Testing and Research Institute for Chemical Convergence, Comparative Examples, Examples 1, 2, 4 and 5 are our own tests and results in the applicant's laboratory.

From the above physical properties and appearance evaluation results, the present invention has a tensile strength of 50 to 61 M/mm in the longitudinal direction, 47 to 57 M/mm in the transverse direction, an elongation of 622 to 665% in the longitudinal direction, 664 to 703% in the transverse direction, and a tearing strength in the longitudinal direction. 238~281M/mm in the direction, 261~308M/mm in the transverse direction, and the shrinkage ratio of 73~80% in the longitudinal direction and 17~25% in the transverse direction. It was shrunk with this proper balance, and the film appearance was substantially the same as that of the comparative example.

The biodegradability results according to an embodiment of the present invention are shown in Table 4 below.

1 week 2 weeks 3 weeks 4 weeks 6 weeks 8 weeks 10 weeks

biodegradability
(%) comparative example - - - - - - - Example 1 17 55 80 96 98 99 100 Example 2 17 54 79 96 97 99 100 Example 3 15 51 77 95 97 98 99 Example 4 13 49 76 95 97 98 99 Example 5 11 47 73 94 96 97 98

As a result of the biodegradability test of the present invention, the biodegradability was insignificant until 4 days after the start of the test, and rapidly increased from the 5th to the 20th, and then the elevation gradually decreased until around 28 days. The biodegradation progressed slowly, which is briefly described in Table 4, and it can be seen from Table 4 that the biodegradation is better as the biodegradation period increases.

2 is a test report of the results of the test conducted by the Korea Research Institute of Chemical Convergence (KTR) for the present invention. 3 is a Fourier Transform Infrared Spectrometer (FTIRS), an analysis method that measures the absorption of energy corresponding to vibration and rotation of a molecular skeleton in which a dipole moment is changed by irradiating infrared rays at the Korea Research Institute for Chemical Convergence (KTR) for the present invention. A Fourier transform infrared (FTIR) absorption spectrum performed using an Infrared Spectrometer) was stabilized in a nitrogen gas atmosphere and then measured by matching the baseline at a wave number of 4000-400 cm-1.

4 is a nuclear magnetic resonance (NMR) spectrum conducted by using a Nuclear Magnetic Resonance Spectrometer (NMR) at the Korea Research Institute of Chemical Convergence (KTR) for the present invention. Deuterated trichloromethane (CDCl3) solvent Then, from this solution, a nuclear magnetic resonance (NMR) spectrum was measured using hydrogen nuclear magnetic resonance (NMR) with a frequency of 250 MHz or higher.

5 is a thermogravimetric analysis spectrum conducted by using a thermo-gravimetric analysis (TGA) at the Korea Research Institute of Chemical Convergence (KTR) for the present invention. The thermogravimetric curve was obtained by increasing the temperature, and the amount of starch decomposition was determined at the midpoint between the initial decomposition starting point of starch (Wi) and the starting point of the decomposition of aliphatic polyester in the derivative curve obtained by differentiating the thermogravimetric curve (Wf). was calculated from

The terms or words used in the specification and claims of the present invention are not to be construed as limited in their ordinary or dictionary meanings, and the inventor can properly define the concept of the term to best describe his invention. Based on this point, it should be interpreted as meaning and concept consistent with the technical idea of the present invention.

Therefore, the embodiment described in the detailed description of the present invention and the configuration shown in the drawings are only the most preferred embodiment of the present invention, so the scope of the present invention should not be limited to the described embodiment and should not be defined at the time of filing of the present invention It should be understood that modifications are possible or may exist, and should be defined by the claims and equivalents.

Claims (5)

In the biodegradable heat-shrinkable film,
The biodegradable heat-shrinkable film comprises 30 to 70 wt% of polybutylene succinate (PBS) having an average molecular weight of 140,000 to 280,000 and 30 to 70 wt% of polybutylene adipate terephthalate (PBAT) having an average molecular weight of 140,000 to 280,000,
Biodegradable heat-shrinkable film, characterized in that it further comprises 1 to 3% by weight of a compatibilizer based on 100% by weight of the polybutylene succinate (PBS) and polybutylene adipate terephthalate (PBAT) mixture.
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