KR20030019726A - PCL/PVC polymer and biodegradable films and sheets manufactured by using it - Google Patents

Abstract

PURPOSE: Provided are a polycaprolactone(PCL)/polyvinylchloride(PVC) polymer and biodegradable film and sheet using the polymer, which have increased tensile strength than that of polyvinyl chloride and can be used for mulching films for agriculture, vinyl bags for waste food, and PVC films and sheets. CONSTITUTION: The PCL/PVC polymer comprises 87-99.99wt% of the PVC and 0.01-13wt% of the PCL. And the biodegradable film and sheet are produced by a process comprising the steps of: blending PVC, PCL, a lubricant, and a heat-stabilizer in an extruder at 80-250deg.C for 0.5-30 minutes; cooling the blended PCL/PVC at 10-25deg.C; forming pellets having a particle diameter of 2mm; molding the pellets by using a calender, a blow mold, a press mold, and etc. and then cooling at 10-25deg.C.

Description

Polycaprolactone / polyvinyl chloride polymer and biodegradable films and sheets using the same {PCL / PVC polymer and biodegradable films and sheets manufactured by using it}

The present invention relates to a biodegradable film and sheet prepared by blending polycaprolactone (PCL) and polyvinyl chloride (PVC) and a method for producing the same. More specifically, the present invention relates to a film and a sheet capable of increasing strength and biodegradation than PVC prepared by blending PCL and PVC, and a method of manufacturing the same.

Polymer blends are considered economically a very important way to make new polymer materials. In addition, the polymer blend changes its physical properties depending on various factors such as the composition of the additive, molecular weight, morphology and compatibility. Therefore, research into the compatibility of the polymer blends and efforts to find a rule that can control the mechanical properties and physical properties of the final product is actively made.

Among other polymers, poly (vinyl chloride) (WV Titow, PVC Plastics, p. 10, Elsevier, London (1990)), which is inexpensive and has excellent mechanical properties, is compatible with other polymers. Much research has been done to find them (LA Utracki, Polymer Alloys and Blends, p. 64, Hanser, New York (1990); O. Olabisi, LM Robeson, and MT Shaw, Polymer-Polymer Miscibility, p. 219). , Academic Press, New York (1979), among which we describe poly (ε-caprolactone) (PCL), known as PVC and a biodegradable polymer (A. Iwamoto and Y. Tokiwa, Polym. Degrad. Stab. , 45 , 205 (1994)), with only one glass transition temperature ( T _g ) in the PCL / PVC blend system, ranging from 0% to 100% PCL content, with excellent compatibility across the entire composition range. (FB Khambatta, F. Warner, T. Russel, and RS Stein, J. Polym. Sci. Polym. Phys. Ed. , 14 , 1391). (1976); JV Koleske and RD Lundberg, J. Polym. Sci.Part A-2 , 7 , 795 (1969); FC Chiu, Basic Studies of Miscibility and Interdiffusion of Vinyl Chloride Polymers and Poly (ε-Caprolactone) Blends, Masters Thesis, University of Akron (1991).

As for the study of the interaction between PCL and PVC molecules with high compatibility, such as PCL / PVC blends, Fourier transform infrared spectrometer (FTIR) is widely used (MM Coleman and J. Zarian, J. Polym. Sci ., 17 , 837 (1979). The FTIR method provides useful information on the compatibility of polymers by observing the position shift, width change, and relative peak height change of spectral peaks of functional groups involved in intermolecular interaction. The interaction between these polymers is known to affect various properties such as morphology, compatibility, and mechanical properties.

The semi-plasticization effect among the changes of mechanical properties by adding additives to polymers is a phenomenon that occurs when a small amount of low molecular weight plasticizers and diluents are added to polymers. (tensile strength) increases and impact strength and elongation are known to decrease (M. Shuster, M. Narkis, and A. Siegmann, Polym. Eng. Sci. , 34 (21), 1613 (1994); SJ Guerrero, Macromolecules , 22 , 3480 (1989)). In the case of general plasticizers, up to about 20% of the content is a semiplasticized region. As the amount of the plasticizer increases, tensile modulus and tensile strength increase, and impact strength and elongation decrease.

In the study of semi-plasticization phenomenon, many studies have been published between the polymer and the oligomer which acts as a plasticizer, but the study of the semi-plasticization between the polymer and the polymer is insignificant. In particular, no studies on the semiplasticization effects on the thermal behavior and mechanical properties of PCL / PVC blends at low PCL contents of 0.01-13% have not been reported. The study of semiplasticization of PCL / PVC blends is a very important factor to control the mechanical properties of the final product for PCL content of less than 30% with commercially available properties.

In view of the above, the present inventors have prepared a pellet by mixing and blending PCL and PVC, and manufacturing the pellet into a film and a sheet, and then measuring T _g using a differential scanning calorimeter using the PCL / PVC blend film. After the FTIR analysis, the present invention was completed by measuring tensile strength and elongation and performing biodegradability test.

Therefore, an object of the present invention is to blend PCL and PVC to provide a PCL / PVC polymer biodegradable while increasing the strength than PVC. Another object of the present invention is to provide a film and sheet capable of biodegradation while increasing strength than PVC manufactured using PCL / PVC polymer. Still another object of the present invention is to provide a biodegradable film and sheet prepared by blending PCL and PVC as agricultural mulching film, food plastic bag, PVC film and sheet.

The object of the present invention is to prepare a pellet by mixing and blending PCL and PVC, and to produce the pellets into a film and sheet and to measure the T _g by using a differential scanning calorimeter using the PCL / PVC blend film and FTIR analysis This was achieved by measuring the tensile strength and elongation afterwards and performing a biodegradability test.

Hereinafter, the configuration of the present invention.

1 is a block diagram illustrating a process of manufacturing a film and a sheet by blending PCL and PVC.

2 is a graph showing the T _g of PCL / PVC blend according to PCL content.

Figure 3 is a graph comparing the T _g experimental value of the PCL / PVC blend and the value by the FOX equation.

4 shows FTIR spectra of PCL and PCL / PVC blends.

5 shows the stress-strain curves of PCL and PCL / PVC blends.

6 is a graph showing the change in tensile strength according to the PCL content change.

7 is a graph showing a change in elastic modulus according to the PCL content change.

8 is a graph showing the change in yield strength according to the PCL content change.

9 is a graph showing the change in elongation rate according to the change in PCL content.

10A is a preculture micrograph of a PCL / PVC film.

10B is a micrograph after 8 weeks of culture of PCL / PVC film.

The present invention is to prepare a pellet by mixing and blending PCL and PVC; Molding the pellets to produce films and sheets; Measuring the T _g of the PCL / PVC blend film obtained in the step via differential scanning thermal analysis; Analyzing the PCL / PVC blend film with an FTIR spectrometer; Measuring tensile strength and elongation of the PCL / PVC blend film; Measuring biodegradability of the PCL / PVC blend film.

In the present invention, the cooling process is carried out by a general air-cooled or water-cooled technique and the air-cooled is possible by forced ventilation with a fan and the temperature range of the two techniques is 10-25 ℃.

PCL / PVC polymer produced by the present invention exhibits a semi-plasticizing effect can be used as a substitute for agricultural mulching film, food plastic bags, PVC film or sheet. In addition, because of the semi-plasticizing effect it can be used to replace the PCL as a plasticizer in the general PVC film and sheet production.

Hereinafter, the specific method of the present invention will be described step by step with reference to Examples, but the scope of the present invention is not limited only to these Examples.

Example 1 Film and Sheet Preparation by PCL / PVC Blend

Step 1: manufacture PCL / PVC pellets

PVC [Hanhwa General Chemical Co., Ltd.] and PCL (Union Carbide Co., USA) were used by drying in an oven at room temperature for 24 hours. The thermal stabilizer of PVC was purchased by using a liquid Sn-based, lead-based, zinc-based, etc., and a lubricant such as stearic acid was used. PCL / PVC blends were blended using an extruder at 0-100% by weight.

0.1-5% of the lubricant and 0.5-5% of the heat stabilizer were mixed in a mixer for 5 minutes to 5 hours so as to be sufficiently absorbed into the PVC particles, and the PVC mixture was blended using a PCL and an injection machine. The temperature of the injection machine was changed to 80-250 ° C. according to the content of PCL, and the stirring speed of the screw was 100-3,000 rpm. In order to minimize the thermal decomposition of the PVC during blending, the total mixing time was 0.5 to 30 minutes.

The blended PCL / PVC was cooled to 10-25 ° C and then prepared into pellets having a particle size of 2 mm using a pelletizer.

Step 2: manufacture PCL / PVC film and sheets

The pellets prepared by the method of the first step are molded using a calendering, blow molding machine, compression molding machine, etc., and then cooled at 10 to 25 ° C. to produce films having a thickness of 1 μm to 1 mm and sheets of 1 mm to 1 cm, respectively. (FIG. 1).

Experimental Example 1: Differential Scanning Thermal Analysis of PCL / PVC Blends

Differential scanning calorimetry (TA Instruments, MDSC 2920) was used to measure the T _g of the PCL / PVC blends and was raised to 10 ° C./min under a stream of nitrogen.

The film prepared in Example 1 was dried in a vacuum oven for 24 hours, and then 1-15 mg was put in an aluminum pan to measure the T _g value of the PCL / PVC blends. The temperature was increased to 150 ° C. and then cooled and increased from −100 ° C. to 150 ° C. in the 2nd-run. The T _g value was measured at 2nd-run and the thermal behavior was investigated.

As a result, the T _g value of 2nd-run measured using differential scanning calorimeter (DSC) for the PCL / PVC blend was as shown in FIG. 2 according to the PCL content. The results are reported in Table 1.

T _g secondary measurement results for PCL / PVC blends PCL / PVC (wt / wt%) T _g (℃) T _m (℃) 0/100 75.7 - 5/95 61.6 - 9/91 50.8 - 13/87 45.6 - 16/84 33.2 - 23/77 22.2 - 100/0 -68.1 56.2

In the results of Figure 2 and Table 1, only one T _g of the total PCL / PVC blend in the total content of the PCL blend was observed that as the PCL content increases it becomes lower than the T _g of pure PVC. The PCL / PVC blend showed only one T _g and no crystalline peak, indicating that PCL and PVC had good compatibility while the composition of PCL was amorphous at 5 ~ 23%. As a result, the two blended polymers were found to be well mixed at the molecular level.

Also in Figure 2 the T _g value of the T _g value and the experimentally PCL / PVC blends measured by a theoretically calculated using the Fox under the formula (1) which is well applicable to amorphous polymers during and blend excellent in compatibility polymer Indicated.

1 / T _g = w ₁ / T _g1 + w ₂ / T _g2 ---------------------- (1)

In Formula (1), 1 and 2 represent PCL and PVC, respectively, T _g represents the glass transition temperature of the PCL / PVC blend and w represents the weight fraction. The slight difference between (1) expression, Fox equation was used to calculate the measured at T g values and the experimental T g value of the results of the two values shown in Figure 3, but experimental data to Following this fine obtained from the Fox equation Could know. The results show that PCL / PVC blend with PCL content of 5 ~ 23% is an amorphous polymer and the compatibility of the two polymers is excellent.

Experimental Example 2 Infrared Spectroscopy Analysis of PCL / PVC Blends

In order to observe the intermolecular interactions for the melt-blended PCL / PVC blends, the FTIR spectra were measured according to the composition change of PCL for PVC. FTIR spectroscopy analysis was carried out at room temperature by fixing a film cut to 15 × 15 mm in a fixed frame to fix the position of the infrared ray transmitting film. The measurement range was 4000 ~ 400 cm-1 and the resolution was 2 cm-1. And scan was performed 400 times. FTIR used Jasco's FTIR-620, and a DTGS (Deuterated triglycine sulfate) detector was used.

As a result, the behavior of the C = O stretching vibration peak is shown in FIG. 4. The spectra of FIG. 4 are the CH bending vibration peaks (S. Krimm, VL Folt, JJ Shipman, and AR Berens, J.) that appear at 1330 cm −1 of the PVC spectrum as spectra measured at room temperature for melt mixed PCL / PVC blend films. Based on Polym. Sci.Part A , 1 , 2621 (1963)), the spectrum of pure PVC was subtracted until the CH bending vibration peak was completely canceled, and the spectra were obtained. The C = O region of the PCL / PVC blend was 1760∼ An enlarged range of 1700 cm −1 is shown.

C = O peak of pure PCL showed peak over a wide range from 1760 to 1700 cm-1, and solid-phase PCL had a C = O stretching vibration peak of amorphous region at 1724 cm-1. Is known to appear at 1737 cm −1. Therefore, the wide C = O stretching vibration peak in pure PCL is the C = O peak where the crystal region and the amorphous region coexist. 4, as the amount of PCL added to PVC increases, the C = O stretching vibration peak positions are 1730.9 cm-1 (5%), 1731.1 cm-1 (9%), 1731.3 cm-1 (13%), and 1731.4 cm -1 (16%) and 1732.0 cm -1 (23%) shifted by ~ 1 cm-1 toward the higher wave, and amorphous peaks of pure PCL were observed at 1734.2 cm-1.

As a result, the C = O stretching vibration peak of the PCL / PVC blend was observed in the low frequency region lower than the C = O peak of the pure PCL, and shifted to the higher frequency as the PCL content increased. The behavior of these C = O peaks is due to certain interactions, such as hydrogen bonding between the C = O group of pure PCL and the α-hydrogen of PVC, compared with the results of blending by solution mixing. The melt-blended blends also showed strong interactions between the two polymers at PCL content of 5-23%.

Experimental Example 3 Investigation of Mechanical Properties of PCL / PVC Blends

In order to investigate the effect of intermolecular interaction on the mechanical properties at low PCL content up to 23% in PCL / PVC blend system, Instron's Universal Test Machine, Model 4465). The tensile strength and elongation were measured with a dumbbell type specimen of ASTM 638 (type IV). The measured value was measured 7 times, and the upper limit and the lower limit were discarded, and 5 average values were obtained. The measurement conditions were 50 mm / min cross head speed and 2.5 cm gauge length.

The stress-strain curves of pure PVC, pure PCL and PCL / PVC blends are shown in FIG. 5, and the measured tensile properties are shown in Table 2. 6 to 9 show graphs of tensile strength, elastic modulus, yield strength, and elongation rate as the PCL content is increased to 23% in PVC.

Tensile Properties of PCL / PVC Blends PCL / PVC (wt / wt%) Tensile Strength (MPa) Modulus of elasticity (MPa) Yield strength (MPa) Elongation (%) 0/100 39.9 1279 67.0 436. 5/95 42.5 1325 70.6 16.0 9/91 45.2 1213 67.1 15.6 13/87 41.0 1186 64.7 28.5 16/84 27.3 961 49.1 135.7 23/77 27.4 263 6.3 397.3 100/0 21.8 162.4 17.3 1300

The tensile strength change according to the PCL content of FIG. 6 showed the highest tensile strength at about 11% PCL content, and it was observed that the PCL content was higher than that of pure PVC at 0.01-13%. Through the above results, it can be seen that the PCL / PVC blend film has a higher strength than pure PVC to about 13% PCL content.

The change in elastic modulus according to the change in PCL content is shown in FIG. 8. The maximum modulus and yield strength were observed at about 5% of PCL content, and it was found that the elastic modulus and maximum yield strength value began to decrease as PCL content increased by more than 5%. In the change in elongation according to the PCL content of FIG. 9, the minimum elongation is shown at about 9% and the elongation is increased more than pure PVC at 13% or more.

In general, when blending PVC with good mechanical properties and PCL with lower mechanical properties than PVC, it is common that the mechanical properties decrease to about 50% as the PCL content increases. However, in the experimental results of FIGS. 6 to 9, in the PCL / PVC blend, the mechanical properties were increased in the PCL composition of 0.01-13%. Therefore, it was found that the PCL / PVC blend system exhibits a semiplasticization effect up to 0.01-13% of the PCL content.

Experimental Example 4 Investigation of Biodegradability of PCL / PVC Blends

For biodegradability test of PCL / PVC film, 12.8g Na ₂ HPO ₄ · 7H ₂ O, 3.0g KH ₂ PO ₄ , Nag 0.5g, NH ₄ Cl 1.0g were dissolved in distilled water and adjusted to 1 liter as the basic medium. The medium was prepared by sterilization for 15 minutes at ℃. At this time, the only carbon source was a 200 μm thick PCL / PVC film cut into 0.5 × 0.5 cm and sterilized separately with 70% alcohol and added in an amount of 2% (W / V). 30 ml of the medium prepared as described above was placed in a 100 ml Erlenmeyer flask, and 100 µl of the soil microorganism was inoculated. Soil microorganisms were used to scrape the surface of the soil, suspended 1g of this in 10ml sterile distilled water and left for 10 minutes to take the clear water above. Inoculate the cells by the above method, and incubate the cells for 8 weeks while stirring at 30 rpm at 150 rpm, and collect the PCL / PVC after 8 weeks, and examine the film before the culture and the film after the incubation with a scanning probe microscope (SPM: Scanning Probe Microscopy). The magnification of the microscope was adjusted to about 50,000 times and photographed.

As a result of the test, soil microorganisms were grown after 8 weeks, and the bacteria were identified as three bacteria and two fungi. In addition, when observed 50,000 times with a scanning probe microscope, the surface of the PCL / PVC film before incubation (FIG. 10a) was clean, but after 8 weeks, the film (FIG. 10b) was biodegraded by soil microorganisms, and thus many holes were observed. there was.

As described above, the PCL / PVC blend film and sheet of the present invention has an excellent effect capable of biodegradation while increasing strength than PVC, so it is very useful in agricultural and household film and vinyl industries as well as in household waste processing industry. It is a useful invention.

Claims (3)

A PCL / PVC polymer characterized by mixing 87-99.99 wt% of polyvinyl chloride (PVC) and 0.01-13 wt% of polycaprolactone (PCL). The PCL / PVC polymer according to claim 1, which is for agricultural mulching films, food plastic bags, PVC films or sheets. PVC film or sheet production method characterized by using PCL as a plasticizer.