KR101576974B1 - Blown film - Google Patents
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- KR101576974B1 KR101576974B1 KR1020120139077A KR20120139077A KR101576974B1 KR 101576974 B1 KR101576974 B1 KR 101576974B1 KR 1020120139077 A KR1020120139077 A KR 1020120139077A KR 20120139077 A KR20120139077 A KR 20120139077A KR 101576974 B1 KR101576974 B1 KR 101576974B1
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Abstract
The present invention relates to a blown film having biodegradability and excellent flexibility. Wherein the blown film comprises at least two predetermined block copolymer repeating units each having a hard segment of a polylactide repeating unit bonded to both ends of a soft segment of the polyether polyol repeating unit, ≪ RTI ID = 0.0 > lactide < / RTI >
Description
The present invention relates to a blown film having biodegradability and excellent flexibility.
The polylactide (or polylactic acid or polylactic acid) resin is a kind of resin containing a repeating unit represented by the following formula. Because these polylactide resins are biomass-based, unlike conventional crude oil-based resins, it is possible to utilize recycled resources and produce less CO 2, which is a global warming gas, than conventional resins. , Biodegradable by moisture and microorganisms at the time of landfilling, and has appropriate mechanical strength similar to that of conventional crude oil-based resins.
[General formula]
Such polylactide resins have been used primarily in disposable packaging / containers, coatings, foams, film / sheet and textile applications. However, such a polylactide resin or a copolymer containing it is disadvantageous in that it is weak in impact and poor in flexibility when it is processed into a film form or the like and used as a packaging film or the like. Particularly, due to the poor flexibility, it produces a very loud noise when manufactured in the form of a film, which has been a limitation on practical commercialization.
Moreover, since the polylactide resin is insufficient in flexibility, it causes problems such as tearing or pitting during processing into a blown film. Thus, polylactide resin alone can not be processed into a blown film. However, it is only necessary to mix other biodegradable resins such as polybutylene succinate (PBS) resin or polybutylene adipate-co-terephthalate (PBAT) It has been known that it can be processed as a blown film. However, since the PBS resin or the PBAT resin has a very high unit price, it causes a large increase in the unit price of the product. In spite of various advantages of the blown film, the polylactide resin is not properly processed into a blown film, There is a limit to the fact that.
Furthermore, even when the PBS resin or the PBAT resin is mixed in an equivalent amount to form a blown film of a polylactide resin, even such a blown film does not exhibit sufficient flexibility and elongation.
Accordingly, it is an object of the present invention to provide a blown film containing a polylactide resin and having biodegradability and excellent flexibility.
The present invention relates to a resin composition comprising two or more block copolymerized repeating units of the formula (1) wherein the hard segment of the polylactide repeating unit is bonded to both ends of the soft segment of the polyether polyol repeating unit, ≪ RTI ID = 0.0 > a < / RTI > lactide copolymer,
[Chemical Formula 1]
Wherein D is a linear or branched alkylene group having 2 to 10 carbon atoms, x is independently an integer of 30 to 500, and n is an integer of 30 to 1000.
Hereinafter, a blown film according to a specific embodiment of the present invention will be described in detail.
According to one embodiment of the present invention, at least two block copolymerization repeating units of the formula (1) are bonded to both ends of the soft segment of the polyether polyol repeating unit and the hard segment of the polylactide repeating unit is bonded,
There is provided a blown film comprising a lactide copolymer wherein the block copolymeric repeating units are linked to each other via a urethane linkage:
[Chemical Formula 1]
Wherein D is a linear or branched alkylene group having 2 to 10 carbon atoms, x is independently an integer of 30 to 500, and n is an integer of 30 to 1000.
The blown film of this embodiment includes a lactide copolymer that satisfies certain structural characteristics and the like.
Such lactide copolymers include block copolymerized repeating units of the above formula (1) wherein the hard segment of the polylactide repeating unit is bonded to both ends of the soft segment of the polyether polyol repeating unit derived from polyalkylene glycol or the like. Such a block copolymerization repeating unit is contained in the copolymer in a plurality of two or more, and these copolymer repeating units are connected to each other via a urethane linking group.
Depending on the structure of the block copolymerized repeating unit of the lactide copolymer and the linkage structure of these repeating units, the lactide copolymer may contain a predetermined soft segment and may be added to a previously known polylactide resin or a lactide copolymer It can exhibit excellent flexibility. In addition, since the soft segment for improving the flexibility is bonded to the lactide copolymer by the above-mentioned linking structure, there is less possibility that the soft segment is discharged during processing or use.
Due to the excellent flexibility of such specific lactide copolymers, it has been found that even when used singly, the film can be processed into a blown film without causing problems such as tearing or pitting of the film during processing. In addition, the blown film containing such a lactide copolymer is excellent in flexibility and high elongation even when other expensive biodegradable resin such as polybutylene succinate (PBS) or polybutylene adipate-co-terephthalate (PBAT) Respectively.
Thus, according to one embodiment, a blown film including a lactide-based copolymer exhibiting biodegradability and exhibiting excellent flexibility and elongation can be provided for the first time. This makes it possible to greatly expand the applicability of the polylactide-based resin and to provide a biodegradable blown film having excellent physical properties while lowering the product cost. Such a blown film is highly preferable for various packaging films .
Hereinafter, the lactide copolymer and the blown film containing the lactide copolymer as a main component will be described in more detail.
As described above, the lactide copolymer contained as a main component in the blown film of one embodiment contains a block copolymerized repeating unit in which the hard segment of the polylactide repeating unit is bonded at both ends of the soft segment of the polyether polyol repeating unit And the block copolymerization repeating units have a form of being connected to each other via a urethane linkage.
In such a lactide copolymer, the urethane linking group may be derived from a polyisocyanate compound having an isocyanate group having two or more hydroxyl groups per molecule. For example, the urethane linker may be a polyisocyanate compound having a terminal hydroxyl group derived from a polylactide repeating unit, And may contain two or more urethane bonds formed by the reaction. That is, the block copolymerization repeating units may be connected to each other by two or more urethane bonds contained in the urethane linking group.
Also, the polyisocyanate compound for forming such a urethane linkage has an average equivalent of isocyanate group per molecule of about 2 or more, or about 2 to 3, or about 2 to more than 3, or about 2.1 to about 2.9, or about 2.2 to about 2.8 Isocyanate compound.
Herein, the equivalent of the average isocyanate group per molecule is about 2 or more, or about 2 to about 3 means that the diisocyanate compound having two isocyanate groups per molecule (equivalent weight of the average isocyanate group per molecule = 2) A polyisocyanate compound having an isocyanate group (the equivalent of an average isocyanate group per molecule = 3 or more), or a mixture thereof (e.g., an equivalent of an average isocyanate group per molecule = less than 3). The urethane linking group derived from such a polyisocyanate compound may include a linking group having a linear structure containing two urethane bonds per molecule or a linking group having a branched structure including three or more urethane bonds, A connector may also be included.
Accordingly, the plurality of block copolymerized repeating units contained in the lactide copolymer may be connected to each other by a urethane linking group having a linear structure, a urethane linking group having a branched structure, or a urethane linking group including them.
Due to the structure of the above-mentioned block copolymerization repeating units and their linkage forms, the lactide copolymer and the blown film of one embodiment can exhibit the following characteristics.
First, since the lactide copolymer contains a soft segment of a polyether polyol repeating unit, it can exhibit excellent flexibility, and there is almost no fear that such a soft segment will be discharged during processing or use due to the above-mentioned connecting structure. As described above. Therefore, by using such a lactide copolymer, it is possible to process a blown film alone without mixing another biodegradable resin, and such a blown film can exhibit excellent flexibility and elongation. In addition, due to such a linking structure, the lactide copolymer and the blown film of one embodiment can have a larger molecular weight and excellent mechanical properties, and can also facilitate control of all properties.
In addition, in the above-mentioned lactide copolymer, the above-mentioned plurality of block copolymerization repeating units may be connected to each other only by a linking group of either a urethane linking group having a linear structure or a urethane linking group having a branched structure, but the urethane linking group As shown in FIG. In this case, the lactide copolymer may simultaneously contain a linear copolymer chain and a branched copolymer chain. As a result, the lactide copolymer can exhibit a high melt viscosity even at the same molecular weight while having a larger molecular weight, thereby exhibiting excellent mechanical properties and melt processability. Therefore, such a lactide copolymer and a composition containing the same can be processed to make it easier to form a blown film of one embodiment, and such a blown film can exhibit excellent mechanical properties and the like.
If the urethane linking group comprises only urethane linkages in a branched structure (for example, when the urethane linking group is derived from a polyisocyanate compound having an average isocyanate group equivalent per molecule of more than 3), the lactide linkage The molecular weight of the cohesive may become excessively large, and a gel may be formed, so that substantial processing, etc. may be difficult. This may lower the processability and the like for obtaining a blown film in one embodiment.
On the other hand, as the polyisocyanate compound for forming the urethane linking group described above, it is preferable that the equivalence of the diisocyanate compound and the isocyanate group is in the range of about 2 or more, for example, 3 or a polyisocyanate compound or a mixture thereof.
Specific examples of the diisocyanate compound include ethylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate (HDI), 1,2-dodecane diisocyanate, cyclohexane- Diisocyanate, cyclohexane-1,4-diisocyanate, 2,4-hexahydrotoluene diisocyanate, 2,6-hexahydrotoluene diisocyanate, hexahydro-1,3-phenylene diisocyanate, hexahydro- 1,4-phenylene diisocyanate, perhydro-2,4-diphenylmethane diisocyanate, perhydro-4,4'-diphenylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-stilbene diisocyanate, 3,3'-dimethyl-4,4'-diphenylene diisocyanate,
In the structure of the above-mentioned lactide copolymer, the soft segment of the polyether polyol repeating unit contained in the block copolymerized repeating unit of the formula (1) may be a polyether polyol polymer, for example, a polyalkylene glycol having 2 to 8 carbon atoms And can be a derived repeating unit. More specifically, the polyether polyol repeating unit is composed of a repeating unit of polyethylene glycol, a repeating unit of poly (1,2-propylene glycol), a repeating unit of poly (1,3-propylene glycol), and a repeating unit of polytetramethylene glycol ≪ / RTI >
In the above-mentioned lactide copolymer, each of the block copolymerized repeating units of the above formula (1) may have a weight average molecular weight of about 50,000 to 200,000, or about 70,000 to 180,000, and the lactide The copolymer may have a weight average molecular weight of about 100,000 to 1,000,000, or about 100,000 to 500,000. The lactide copolymer may have such a large molecular weight, and the blown film of one embodiment containing the lactide copolymer may exhibit mechanical properties such as excellent strength.
The polyether polyol repeating units included in the lactide copolymer may have a number average molecular weight of about 1,000 to 15,000, or about 2,000 to 13,000, or about 3,000 to 10,000, respectively. By including a polyether polyol repeating unit having such a large molecular weight in such a range as a soft segment, the lactide copolymer and the blown film of one embodiment including the same can exhibit and maintain greater flexibility, and the lactide copolymer The blown film of one embodiment can exhibit excellent mechanical properties.
Further, in the above-mentioned lactide copolymer, each of the block copolymerization repeating units may contain about 50 to 95% by weight, or about 60 to 90% by weight, of the hard segment and a remaining soft segment, for example, about 5 to 50 Percent by weight, or about 10 to 40 percent by weight soft segment. If the content of the hard segment is excessively low, the mechanical properties such as the strength of the lactide copolymer and the blown film containing the same may deteriorate. On the contrary, when the content of the hard segment is excessively high or the content of the soft segment is excessively low, the flexibility of the lactide copolymer may be deteriorated. For this reason, there is a high possibility that problems such as tearing of the film during processing are reduced due to poor workability in the blown film, and the flexibility of the finally produced blown film may be lowered. In addition, when the content of the soft segment is excessively high, the lactide copolymer may be decomposed to further deteriorate mechanical properties. This is expected because the soft segment can act as a kind of initiator to promote depolymerization or decomposition of the lactide copolymer, particularly the hard segment of the polylactide repeat unit.
On the other hand, the above-mentioned lactide copolymer can be obtained by ring-opening polymerization of a lactide monomer using a specific catalyst in the presence of a macro-initiator of a polymer constituting a polyether polyol repeating unit. This particular catalyst can be a catalyst comprising an organometallic complex of the
(2)
(3)
[Chemical Formula 4]
In the
Block copolymerization repeating units can be obtained through a process in which the lactide monomer is ring-opened and polymerized to form a hard segment by the catalyst, and the hard segment is copolymerized with the soft segment derived from the macromonomer. The above-mentioned lactide copolymers can be produced.
However, such a specific catalyst has a much better polymerization activity than previously known, and enables the production of a polylactide repeating unit having a large molecular weight in a small amount. Accordingly, the lactide copolymer may have a large molecular weight of the hard segment and the soft segment, and a large weight average molecular weight as described above due to the structure in which the block copolymerization repeating units of the formula (1) are connected. Therefore, the lactide copolymer and the blown film of one embodiment containing it can exhibit excellent mechanical properties.
The above-mentioned lactide copolymer contains a [hard segment] - [soft segment] - [hard segment] composed of [polylactide repeat unit] - [polyether polyol repeat unit] - [polylactide repeat unit] By including two or more block copolymer repeat unit structures, biodegradability specific to biomass-based resins can be exhibited. Further, as the polyether polyol repeating unit of the soft segment is formed from a polyether polyol polymer derived from biomass, for example, a polyalkylene glycol having a degree of biodegradation of about 100% based on the ASTM D6400 experiment, The lactide copolymer may exhibit higher biodegradability. Due to the biodegradability of such lactide copolymers and the like, the blown film of one embodiment can also exhibit excellent biodegradability.
On the other hand, the above-mentioned lactide copolymer is obtained by ring-opening polymerization of a lactide monomer to form a block copolymer of the formula (I) in the presence of an initiator containing a tin or zinc containing catalyst and a polyether polyol polymer; And reacting the block copolymer of formula (I) with a polyisocyanate compound having an isocyanate group having at least two diols per molecule:
[Formula 1a]
In the above formula (I), D is a linear or branched alkylene group having 2 to 10 carbon atoms, x is independently an integer of 30 to 500, and n is an integer of 30 to 1000.
According to such a production method, in the first step, a hard segment of a polylactide repeating unit is formed, and this is combined with a soft segment derived from an initiator of a predetermined polyether polyol polymer to prepare a block copolymer of the above formula (1a) In the second step, it may be combined with an isocyanate compound to prepare the above-mentioned lactide copolymer.
At this time, the polyether polyol polymer acts as a kind of macro-initiator in the formation of the hard segment polylactide repeating unit. That is, the macromonomer may be combined with the organometallic catalyst to initiate the reaction by opening the ring to the lactide monomer, and the chain may be continuously extended to form the hard segment and the block copolymer containing the hard segment. That is, since the hydroxyl groups at both terminals of the polyether polyol polymer initiate the ring-opening polymerization and extend the chain, the block copolymer formed therefrom is a polyether polyol polymer, that is, a polyether polyol polymer having both ends of a hard segment A combined structure can be obtained.
Accordingly, by reacting the block copolymer thus formed with a polyvalent isocyanate compound, a lactide copolymer contained in the blown film of one embodiment can be produced.
In such a preparation method, the tin or zinc containing catalyst may be a catalyst containing the organometallic complex of the above-mentioned formula (2) or a mixture of the compounds of the formulas (3) and (4). By using such a specific catalyst, the finally prepared lactide copolymer can meet a high molecular weight range and the like. As a result, the lactide copolymer and the blown film of one embodiment including the lactide copolymer can exhibit excellent mechanical properties and improved flexibility due to the inclusion of the soft segment.
In the process for producing the lactide copolymer, the lactide monomer may be a cyclic monomer, L-lactide or D-lactide, obtained from L-lactic acid or D-lactic acid. More preferably, L-lactide or D-lactide raw material having an optical purity of 98% or more is preferably used as the lactide monomer in consideration of the melting temperature and heat resistance of the lactide copolymer.
The polyether polyol polymer may be a polyalkylene glycol having 2 to 8 carbon atoms and having a number average molecular weight of about 1,000 to 15,000, or about 2,000 to 13,000, or about 3,000 to 10,000. Specific examples thereof include polyethylene Polyalkylene glycols selected from the group consisting of glycol (PEG), poly (1,2-propylene glycol), poly (1,3-propylene glycol) and polytetramethylene glycol.
The ring-opening polymerization may be carried out at a temperature of about 120 to 200 ° C, or about 120 to 190 ° C for about 0.5 to 8 hours, or about 1 to 7 hours.
The ring-opening polymerization may be carried out in the presence of a complex of the formula (2) or a mixture of the formulas (3) and (4) as catalysts. The catalyst may be used at a ratio of about 1: 10,000 to 1: 200,000 . If the addition ratio of the catalyst is excessively small, the polymerization activity is not sufficient, which is not preferable. On the other hand, if the addition ratio of the catalyst is excessively large, the amount of the residual catalyst of the produced lactide copolymer becomes large, leading to degradation of the copolymer or reduction of molecular weight .
In the step of reacting the block copolymer with the polyvalent isocyanate compound after the ring-opening polymerization, as the polyvalent isocyanate compound, a compound having an isocyanate group equivalent of about 2 or more, or about 2 to 3 may be used. Are already described above, and further description thereof will be omitted.
The polyisocyanate compound may be used in an amount of about 0.05 to 5 parts by weight, or about 0.1 to 4 parts by weight, or about 0.2 to 2 parts by weight based on 100 parts by weight of the block copolymer of Formula 1a. If the amount of the polyvalent isocyanate compound used is too small, the molecular weight, viscosity or mechanical properties of the lactide copolymer may be insufficient. On the contrary, if the amount of the polyvalent isocyanate compound used is too large, the lactide copolymer may have a too high molecular weight, have.
The reaction with the polyvalent isocyanate compound may be carried out at a temperature of about 100 to 190 DEG C for about 0.001 to 1 hour. However, the range is not particularly limited as long as it is a typical reaction condition for forming a urethane bond.
Further, the reaction with the polyisocyanate compound can proceed in the presence of a tin-based catalyst. Representative examples of such tin-based catalysts include Stannous Octoate, Dibutyltin Dilaurate and Dioctyltin Dilaurate.
On the other hand, the blown film of one embodiment including the lactide copolymer described above may have various thicknesses depending on each use, and may have a thickness of about 10 to 200 占 퐉, or about 10 to 100 占 퐉. For example, when used as a wrapping film such as a wrap film or an envelope, a thickness of about 10 to 50 mu m, a thickness of about 10 to 30 mu m, or a thickness of about 15 to 25 mu m in terms of flexibility, handleability, Lt; / RTI >
The blown film was subjected to a tensile test at a stretching speed of 10 mm / min using an Instron universal testing machine (UTM) according to ASTM D 882. The tensile strength of the blown film was about 20 to 60 MPa, Or about 25 to about 50 MPa, and an elongation of about 20 to about 100 percent, or about 20 to about 60 percent, or about 30 to about 50 percent, and a modulus of about 500 to 2000 MPa, or about 800 to 2000 MPa, or about 1000 to 1800 MPa, About 1100 to 1600 MPa.
Such tensile strength, elongation and modulus range can reflect the excellent flexibility and mechanical properties of the blown film. In addition, the above-mentioned blown film can be manufactured and provided with excellent mechanical properties and flexibility without causing problems such as tearing or pitting of the film during processing due to the inclusion of the above-mentioned lactide copolymer.
If the tensile strength of the blown film is excessively low, the handleability, process transparency, and slit processability of the film may become poor. In addition, when the wrap film is used, the releasability of the film may be insufficient due to insufficient slip of the film, and efficient packaging may be difficult due to deformation of the film before wrapping an article or food such as a container. On the other hand, when the tensile strength is excessively high, folding lines remain unchanged when the film is folded at the time of packaging, so that it may not be apparently bad or may not be deformed depending on the shape of the article or food to be packed.
When the elongation is too low or the modulus is excessively high, flexibility is insufficient and efficient packaging for packaging films such as containers and foods may become difficult. On the contrary, when the elongation is too high or the modulus is excessively low, the handling property of the film, the process permeability, the slit processability are poor, the handling property of the film becomes poor, and even after packaging, .
If necessary, the blown film may be provided with heat sealability or properties required for a food packaging material such as gas barrier properties such as water vapor, oxygen, or carbon dioxide gas, releasability, printability, etc. good. To this end, a polymer or compound having such properties may be added to a film, or a thermoplastic resin such as an acrylic resin, a polyester resin, or a silicone resin, an antistatic agent, a surfactant, a release agent, etc. may be applied to at least one surface of the blown film It is possible. As another method, another film having a function such as a polyolefin-based sealant or the like may be co-extruded to form a multilayer film. Or may be produced in the form of a multilayer film by other methods such as adhesion or lamination.
On the other hand, the above-mentioned blown film can be formed by applying the general inflation method to the above-mentioned lactide-based copolymer. More specifically, the blown film is obtained by melt-extruding the lactide copolymer in an extruder equipped with a blown film die, forming a tube-shaped bubble in the blown film die, And then winding it up and winding it. At this time, an appropriate amount of air may be blown into the bubbles to appropriately adjust the film width and thickness.
In the case of using the former polylactide resin, problems such as tearing or pitting of the film occur due to insufficient flexibility in the process of forming the bubbles or air blowing, so that the polylactide resin alone can not be used It was almost impossible to process the film into a film. However, since the above-mentioned lactide-based copolymer has more excellent flexibility and elongation, it is possible to process a blown film alone, and it is possible to provide a blown film having excellent flexibility and the like.
In the meantime, in the process of manufacturing the blown film, the diameter of the extruder may be, for example, about 30 to 160 mm, or about 35 to 155 mm, and the diameter of the blown film die may be about 70 to 160 mm, 90 to 150 mm. Also, the temperature of the extruder may be about 150 to 250 ° C, and the temperature of the blown film die may be 140 to 200 ° C. Under these conditions, a blown film of one embodiment having excellent physical properties and productivity can be produced.
On the other hand, after the blown film is formed by the above-described method, it is possible to cool the film by applying air at a constant air volume.
The above-mentioned blown film can be suitably applied as a packaging film for various fields, a raw material for fiber spinning, and the like. For example, sanitary films, lamination films, shrinkable labels, and matte films for snack packaging, such as consumer packaged goods or grocery packages, envelopes, refrigerated / frozen food packaging, shrinkable over-wrapping films, Bundle bundle films, sanitary napkins or baby products In addition, it can be widely used as packing materials for industrial materials such as agricultural mulching films, automobile paint film protective sheets, garbage bags and compost pouches.
The present invention enables the formation and delivery of a blown film alone using a particular lactide copolymer. Moreover, such a blown film exhibits excellent flexibility, elongation and the like with excellent mechanical properties, and can exhibit biodegradability peculiar to polylactide-based resin. Therefore, the present invention can further expand the applicability of the polylactide-based resin, and such a blown film of the present invention can be very suitably applied to various wrapping films such as food packaging materials and raw materials for raw materials such as fibers
1 is a 1 H NMR spectrum of the lactide copolymer of Production Example 1.
2 is a graph showing a comparison of the stress-strain curves of the blown films of Example 1 and Comparative Example 1. FIG.
Best Mode for Carrying Out the Invention Hereinafter, the function and effect of the present invention will be described in more detail through specific examples of the present invention. It is to be understood, however, that these embodiments are merely illustrative of the invention and are not intended to limit the scope of the invention.
[Experimental Method]
In the following preparations and examples, all work to treat air- or water-sensitive compounds was carried out using the standard Schlenk technique or the dry box technique. In the following Production Examples and Examples, definition and measurement methods of the respective properties are as summarized below.
(1) Content (wt%) of polylactide and polyether polyol repeating units: Using a 600 Mhz nuclear magnetic resonance (NMR) spectrometer, it was confirmed by 1 H NMR that the block copolymers contained in each prepared lactide copolymer The content of each repeating unit in the repeating unit was determined.
(2) Tg and Tm (占 폚): Using a differential scanning calorimeter (manufactured by TA Instruments), the sample was subjected to melt quenching and then heated at a rate of 10 占 폚 / min. The midline value of the tangent line and the baseline near the endothermic curve were taken as Tg and the maximum value of the melting endothermic peak of the crystal was taken as Tm.
(3) Molecular weight and polydispersity index: Polymer molecular weight and polydispersity index (PDI) were measured using gel permeation chromatography (GPC). Polystyrene samples were standardized.
(4) Preparation of specimen:
To prepare the film, all samples were dried in a 70 [deg.] C vacuum oven for 4 hours before extrusion. Thereafter, the melt extrusion was carried out at an extrusion temperature of 190 ° C in an extruder equipped with a blown film die (manufactured by Korea Emm Co., Ltd., blown film manufacturing machine; extruder diameter: 100 mm, die diameter: 130 mm). Subsequently, a tube-shaped bubble was formed in a 170 占 blown film die, and then a bubble film of 20 占 퐉 in thickness was formed by folding and winding the tubular bubble by a nip roll. Such a blown film was used as a measurement specimen of a universal testing machine (UTM) of the ASTM D 412-C standard.
(5) Tensile strength (TS max, MPa) and stress-strain curve: Using an Instron universal testing machine (UTM) according to ASTM D 882, / min, and the tensile strength was measured. The tensile test conditions were Load cell 10KN, LE position 40mm, and the average value of 5 tests in total was expressed as a result.
(6) Elongation (%): The elongation until the film specimen was broken under the same conditions as the tensile strength measurement was measured, and the average value of the test was measured five times in total.
(7) E-modulus (MPa): The slope of the initial strain of about 0.5% strain was calculated on the stress-strain curve using a universal testing machine (UTM). The tensile test conditions were the same as those of the above tensile strength measurement conditions, and the average value of the total of 5 tests was expressed as a result.
[Synthesis Example 1]
(0.36 g, 1.0 mmol, manufacturer: TCI) of Sn (Oct) 2 (0.2 g, 0.49 mmol, manufacturer: Aldrich) and the following compound of formula (6) were added to a 100 mL flask, and 30 mL of toluene was added thereto. Lt; / RTI > The solvent was then removed under vacuum, washed with heptane solvent and dried to yield 0.36 g of organometallic complex A.
[Chemical Formula 6]
[Synthesis Example 2]
0.4 g of the organometallic complex B was obtained in the same manner as in Synthesis Example 1, except that Sn (Oct) 2 (0.2 g, 0.49 mmol, manufacturer: Aldrich) and 0.36 g of the compound of the formula .
Referring to the 13 C NMR spectrum for the organometallic complex B, three carbonyl peaks in the reaction of the Sn (Oct) 2 catalyst with the compound of the formula 7 appear at d 188 ppm, 183 ppm and 182 ppm, The peak at 188 ppm corresponds to the free Sn (Oct) 2, and the broad peak at d 182 ppm indicates that the compound of formula (7) Organic metal complexes.
(7)
[Production Example 1]
L-lactide monomer (100 kg, 693.82 mol) and the organometallic complex A (102.81 g) of Synthesis Example 1 were fed into a 150 L reactor equipped with a stirrer, a nitrogen inlet pipe, a stirrer, a catalyst inlet and a vacuum system, Glycol (number average molecular weight: 6000 g / mol, 17.65 kg) was charged and subjected to ring-opening polymerization reaction at 180 ° C for 3 hours to prepare a block copolymer of formula (1a). A part of the polymer resin was sampled in the reactor and the weight average molecular weight was measured using GPC (Gel Permeation Chromatography). The weight average molecular weight was 95,000.
Thereafter, 0.59 kg of a polyisocyanate compound having an equivalent number of isocyanate groups per molecule of about 2.7 (a mixture of MDI having an equivalent number of isocyanate groups of 2.0 and hexylene diisocyanate isocyanurate having an equivalent number of isocyanate groups of 3.0) per molecule was fed into the polymerization reactor, The block copolymer of Formula 1a was subjected to addition polymerization reaction at 180 ° C for 30 minutes to form a urethane linkage.
After the completion of the reaction, the residual lactide is removed through a conventional volatilization process to produce a lactide copolymer containing at least two block copolymerization repeating units represented by the formula (1). The lactide copolymer thus prepared is reacted with polylactide and / The content (wt%), the weight average molecular weight, the polydispersity index, the glass transition temperature and the melting temperature of the polyether polyol repeating unit were measured. As a result of the measurement, the content of the polylactide and polyether polyol repeating units in the block copolymerization repeating units was 85 wt% and 15 wt%, respectively, and Mw = 244,000, polydispersity index = 2.57, Tg = 48 캜, and Tm = Respectively. The 1 H NMR spectrum of the lactide copolymer of Production Example 1 is as shown in Fig.
[Example 1]
The lactide copolymer ('F-PLA') according to Preparation Example 1 was dried in a vacuum oven at 70 ° C for 4 hours. Thereafter, the melt extrusion was carried out at an extrusion temperature of 190 ° C in an extruder equipped with a blown film die (manufactured by Korea Emm Co., Ltd., blown film manufacturing machine; extruder diameter: 100 mm, die diameter: 130 mm). Subsequently, a tube-shaped bubble was formed in a 170 占 blown film die, and then a bubble film of 20 占 퐉 in thickness was formed by folding and winding the tubular bubble by a nip roll.
For the film of Example 1, a stress-strain curve was derived and shown in Fig. The modulus, tensile strength and elongation of the film were measured and are shown in Table 1 below.
[Comparative Example 1]
85% by weight of a polylactide resin (NatureWorks 4032D, 'PLA', weight average molecular weight: about 230,000, manufactured by NatureWorks) and 15% by weight of a PBS resin (G4560; Samsung Fine Chemicals) were mixed to form a resin composition .
The resin composition thus prepared was subjected to the same procedure as in Example 1 to prepare a blown film, and then the strain-strain curve of this blown film of Comparative Example 1 was derived and shown together in FIG. 2, Tensile strength and elongation were measured respectively and are shown together in Table 1 below.
(MPa)
(MPa)
(Breaking point;%)
Referring to Table 1 and FIG. 2, in Comparative Example 1, it was impossible to process and form the blown film by using the polylactide resin alone. Therefore, even though 15% by weight of the PBS resin was mixed, , Indicating flexibility.
On the other hand, in Example 1, it was found that not only a predetermined film of lactide copolymer could be processed and formed satisfactorily, but also mechanical properties corresponding to Comparative Example 1 and flexibility (low modulus and high elongation) Respectively.
Claims (12)
Wherein the block copolymeric repeating units comprise a lactide copolymer that is linked to each other via a urethane linkage,
A biodegradable blown film having a tensile strength of 20 to 60 MPa, an elongation of 20 to 100% and a modulus of 500 to 2000 MPa:
[Chemical Formula 1]
Wherein D is a linear or branched alkylene group having 2 to 10 carbon atoms, x is independently an integer of 30 to 500, and n is an integer of 30 to 1000.
The polyisocyanate compound having an equivalent number of isocyanate groups of not less than 3 is not limited to the oligomer of the diisocyanate compound, the polymer of the diisocyanate compound, the cyclic oligomer of the diisocyanate compound, the isocyanurate of hexamethylene diisocyanate (HDI isocyanurate) Isocyanate compounds and isomers thereof. ≪ RTI ID = 0.0 > 21. < / RTI >
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| KR1020120139077A KR101576974B1 (en) | 2012-12-03 | 2012-12-03 | Blown film |
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