TWI681011B - Polylactic acid-polyamide alloy resin composition - Google Patents

Abstract

The present invention provides a polylactic acid-polyamide alloy resin composition. The polylactic acid-polyamide alloy resin composition includes 30 to 90 parts by weight of polylactic acid resin and 10 to 70 parts by weight of polyamide resin, wherein The polylactic acid resin includes a hard segment containing a repeating unit of polylactic acid resin and a polyolefin-based polyol-containing structural unit connected to a linear or branched polyolefin-based polyol repeating using a urethane bond or an ester bond as a medium. The soft segment of the unit, and the organic carbon content rate derived from biomass is 60% or more. The polylactic acid-polyamide alloy resin composition according to the present invention not only shows improved impact resistance, but also is excellent in various physical properties such as heat resistance, moisture resistance, mechanical physical properties, and injection processability, which can be advantageously used Used as a material for molded products, and due to its environmentally friendly properties, it can be devoted to preventing environmental pollution.

Description

Polylactic acid-polyamide alloy resin composition

The present invention relates to a polylactic acid-polyamide alloy resin composition (polylactic acid-polyamide alloy resin composition), and more particularly, to an alloy resin composition including polylactic acid resin and polyamide resin, which not only shows that The improved impact strength, and various physical properties such as heat resistance, moisture resistance, mechanical physical properties, injection molding processability, etc. are excellent, so that it can be advantageously used as a molding material and has environmental protection characteristics.

So far, petroleum-based resins such as polyethylene terephthalate (PET), nylon, polyolefin, or flexible polyvinyl chloride (PVC) have been used as materials for packaging and other purposes widely used. However, since these petroleum-based resins do not have biodegradability, there is a problem in that a large amount of carbon dioxide, which is a global greenhouse gas, is discharged at the time of disposal to induce environmental pollution. Moreover, as petroleum resources are gradually depleted, recently, in the use of biomass-based resins, representative polylactic acid resins are being extensively studied.

However, since these polylactic acid resins are inferior to petroleum-based resins in heat resistance, moisture resistance, mechanical physical properties, and the like, in fact, their applicable fields or applications are limited. especially It is an attempt to use polylactic acid resin as packaging materials such as packaging films. However, due to the low flexibility of polylactic acid resin, these applications are also limited.

In order to overcome the limitations of these polylactic acid resins, a composition of a general-purpose resin and/or engineering plastic alloy different from the polylactic acid resin is used. However, even if such a composition of alloy form is used to obtain a molded product containing polylactic acid resin, in most cases, due to the compatibility problem between the two resins, in fact, the heat resistance and mechanical physical properties are improved. There are limitations.

In addition, recently, in order to solve the above-mentioned problems, a method of additionally introducing clay and an impact modifier when synthesizing a polyamide resin on a polylactic acid resin has been proposed. (Korean Patent Publication No. 2009-0073847). However, the polylactic acid-polyamide alloy resin composition and products still have limitations in overcoming the low compatibility of the polylactic acid resin and the polyamide resin, and the physical property improvement effect is insufficient, so it is difficult to apply to Automotive interior materials with high durability are required. Moreover, such a polylactic acid resin composition has poor melting characteristics due to insufficient compatibility, resulting in a poor extrusion state and a poor molding extrusion state, resulting in a poor product appearance, and mechanical and physical properties, heat resistance and impact resistance Sex is not enough.

In addition, the moisture resistance of polylactic acid resin is usually very weak. The main reason is that the hydrolysis reaction of the water contained in the resin causes a part of the polymer to be decomposed into lactic acid, monomer, or oligomer. Low molecular weight.

In particular, the generated lactic acid, monomers and oligomers volatilize during the molding process of the resin and also induce pollution and corrosion of mechanical devices, and also cause quality problems of the molded products. Specifically, when a sheet is manufactured by extrusion molding, the lactic acid, monomers, and oligomers remaining in the resin are volatilized when the sheet is extruded, which causes a deviation in the thickness of the sheet. Occurs according to the use environment Continuous hydrolysis may cause a reduction in mechanical and physical properties. In addition, according to the characteristics of the polylactic acid resin, it easily absorbs water, so it increases in the state of pellets when it is operated in a water bath to cool it after passing through the extruder or when storing its compounding product When moisture is absorbed and the molded product is extruded using it, problems such as poor appearance or reduced physical properties such as silver streak depending on the moisture in the resin may occur.

Therefore, there is a continuing need to develop a polylactic acid that not only exhibits further improved impact resistance, but also has excellent moisture resistance, and is excellent in various physical properties such as mechanical physical properties, heat resistance, and anti-bleed out characteristics. Resin.

The object of the present invention is to provide a polylactic acid-polyamide alloy resin composition, the polylactic acid-polyamide synthetic composition not only shows improved impact resistance, but also moisture resistance, mechanical physical properties, transparency , Heat resistance, block resistance, molding processability and other physical properties are excellent, so it can be advantageously used as a plastic molding material, and also has environmental protection characteristics.

According to the object, the present invention provides a polylactic acid-polyamide alloy resin composition containing 30 to 90 parts by weight of polylactic acid resin and 10 to 70 parts by weight of polyamine resin, wherein the polylactic acid resin includes The hard segments containing the polylactic acid repeating unit represented by the following Chemical Formula 1 and the polyolefin-based polyol constituent units containing the following Chemical Formula 2 are connected into a straight chain by using a urethane bond or an ester bond as a medium Type or branched type polyolefin polyol repeat unit soft segments (soft segments), and the organic carbon content rate (%C _bio ) derived from biomass defined by the following mathematical formula 1 is 60% or more: [Chemical formula 1]

Carbon atoms [Equation 1]% C _biological = (for the ¹⁴ C isotope ¹² C was isotopes weight ratio of carbon atoms in the polylactic acid resin) / (the biomass from the standard substance weight of the ¹⁴ C isotope ¹² C was isotope Ratio)×100

In the above Chemical Formula 1 and Chemical Formula 2, n is an integer of 700 to 5,000, and m+1 is an integer of 5 to 200.

The polylactic acid-polyamide alloy resin composition according to the present invention not only exhibits improved impact resistance, but also is excellent in various physical properties such as heat resistance, moisture resistance, mechanical physical properties and extrusion processability, which can be advantageous It is used as a material for molded products, and due to its environmental protection characteristics, it can be devoted to preventing environmental pollution.

Figures 1 to 3 are electron microscope (SEM) photographs of the particles prepared in Examples 1 to 3.

FIG. 4 is an electron microscope (SEM) photograph of the particles prepared in Comparative Example 4.

Hereinafter, a polylactic acid-polyamide alloy resin composition according to a specific embodiment of the present invention will be described.

The polylactic acid-polyamide resin composition according to the present invention includes 30 to 90 parts by weight of polylactic acid resin (A) and 10 to 70 parts by weight of polyamide resin (B), and the polylactic acid resin (A ) Includes a hard segment containing a polylactic acid repeating unit represented by the following Chemical Formula 1 and a polyolefin-based polyol constituent unit containing the following Chemical Formula 2 connected to a linear type using a urethane bond or an ester bond as a medium Branched-type polyolefin polyol repeating units are soft segments, and the biomass-derived organic carbon content rate (%C _bio ) defined by the following mathematical formula 1 is 60% or more:

Carbon atoms [Equation 1]% C _biological = (for the ¹⁴ C isotope ¹² C was isotopes weight ratio of carbon atoms in the polylactic acid resin) / (the biomass from the standard substance weight of the ¹⁴ C isotope ¹² C was isotope Ratio)×100

In the above Chemical Formula 1 and Chemical Formula 2, n is an integer of 700 to 5,000, and m+1 is an integer of 5 to 200.

Polylactic acid resin

The polylactic acid resin included in the polylactic acid-polyamide alloy resin composition according to the present invention basically includes the polylactic acid repeating unit represented by the chemical formula 1 in a hard segment. Moreover, the polylactic acid resin includes a polyolefin-based polyol repeating unit in a soft segment, and the polyolefin-based polyol repeating unit has a structural unit of the polyolefin-based polyol represented by the chemical formula 2 as a urethane The bond (-C(=O)-NH-) or ester bond (-C(=O)-O-) is a medium and is connected into a linear or branched structure.

This kind of polylactic acid resin basically includes a polylactic acid repeating unit in a hard segment, so that it can show the unique biodegradability and environmental protection characteristics of the birth substance-based resin. Furthermore, as a result of experiments conducted by the present inventors, it was found that when the polylactic acid resin includes a polyolefin-based polyol in a soft segment, the polylactic acid resin can not only be produced with greatly improved flexibility, but also have A molded product with excellent transparency and low haze value. In particular, the introduction of such a soft segment and a hard segment into the polylactic acid resin in a joined state not only reduces the bleed out of the soft segment for improving flexibility, but also reduces the generation There is a concern about low stability, and there is also a concern that the molded article including the polylactic acid resin or the like has a larger haze value or lower transparency. Moreover, the above-mentioned polylactic acid resin can exhibit the above-mentioned effect without increasing the content of the soft segment for improving the flexibility, and therefore may include a biomass resin having a relatively high content, for example, from Hard segment of polylactic acid resin.

In addition, since the polylactic acid resin contains non-polar soft segments, it has excellent moisture resistance compared to ordinary polylactic acid resins.

The polylactic acid resin contained in the polylactic acid-polyamide alloy resin composition may have an organic carbon content rate (%C _bio ) derived from biomass defined by the mathematical formula 1 of about 60% or more, About 70% or more, about 80% or more. About 85% or more, about 90% or more, or about 95% or more.

If it is different from the polylactic acid resin contained in the polylactic acid-polyamide alloy resin composition of the present invention, the polyester-based repeating unit that is not a polyolefin-based polyol repeating unit is included as a soft segment In order to achieve excellent flexibility, it is necessary to introduce a higher content of other resins such as polyester polyol repeating units derived from fossil fuels, so it may be difficult to achieve the organic carbon content of about 60% (%C _bio ) .

The measurement method of the biomass-derived organic carbon content rate (%C bio) according to the mathematical formula 1 can be implemented according to the method described in the standard of ASTM D 6866, for example. The technical significance and measurement method of this organic carbon content rate (%C _bio ) are further specifically described below.

Generally, unlike organic substances such as resins derived from fossil fuels, it is known that organic substances such as resins derived from biomass (biological resources) include the isotope ¹⁴ C. More specifically, it is known that all organic substances extracted from living organisms such as animals or plants contain ¹² C (about 98.892% by weight), ¹³ C (about 1.108% by weight), and ¹⁴ C (about 1.2×10 ^-10 weight %) and other three isotopes as carbon atoms, and each isotope maintains a certain ratio. This is because the ratio of isotopes in the atmosphere is the same, and living organisms continue metabolic activities while exchanging carbon atoms with the external environment. Therefore, the ratio of these isotopes remains constant.

In addition, ¹⁴ C is a radioisotope, and according to the following mathematical formula 2, its content decreases as time ( t ) passes.

[Mathematical formula 2] n=no. exp(-at)

In the mathematical formula 2, the no represents the initial atomic number of the ¹⁴ C isotope, the n represents the atomic number of the ¹⁴ C isotope remaining after t hours, and the a represents the decay constant (or radioactivity constant) related to the half-life ).

In this mathematical formula 2, the half-life of the ¹⁴ C isotope is about 5,730 years. In view of this half-life, organic substances extracted from living organisms that continue to interact with the external environment, that is, organic substances such as resins derived from biomass (biological resources), although the isotope content is slightly reduced, can be substantially Maintaining a certain ¹⁴ C isotope content ratio and a certain content ratio with other isotopes, for example, can maintain a certain content ratio (weight ratio) ¹⁴ C/ ¹² C=about 1.2×10 ^-12 .

In contrast, fossil fuels such as coal or petroleum are in a state of being cut off for 50,000 years by exchanging carbon atoms with the external environment. From this, when estimating organic substances such as resins derived from fossil fuels based on Mathematical Formula 2, the content of ¹⁴ C isotopes contained is 0.2% or less of the initial content (number of atoms), so it is considered that ¹⁴ C isotopes are not substantially contained.

The mathematical formula 1 is set in consideration of the above content, the denominator may be the weight ratio of isotope ¹⁴ C/ ¹² C derived from biomass, for example, it may be about 1.2×10 ^-12 , and the molecule may be used in the measurement object resin. The weight ratio of ¹⁴ C/ ¹² C is included. As described above, the carbon atoms derived from biomass maintain an isotope weight ratio of approximately 1.2×10 ^-12 , compared with the weight ratio of ¹⁴ C/ ¹² C of isotope elements derived from fossil fuels, which is substantially 0, Based on the above facts, in the polylactic acid resin contained in the polylactic acid-polyamide alloy resin composition, the content ratio (%) of organic carbon derived from biomass in the total carbon atoms can be determined by the mathematical formula 1 C _Creature ).

At this time, the content of each carbon isotope and its content ratio (weight ratio) can be described in the ASTM D6866-06 standard (standard test method for determining the biological basis content of natural substances using radiocarbon and isotope ratio mass spectrometry analysis) 3 One of two methods. Suitably, the carbon atoms contained in the resin to be measured are made into a graphite or carbon dioxide gas form, and measured with a quality analyzer, or measured by liquid flash spectrometry. At this time, when using the quality analyzer, an accelerator for separating ¹⁴ C ions from ¹² C ions is used at the same time to separate the two isotopes, and the content of each isotope can be measured using the quality analyzer And content ratio. Alternatively, the content and content ratio of each isotope can be obtained by using liquid flash spectrometry known to those of ordinary skill in the art, and thus the organic carbon content rate of the mathematical formula 1 can be derived.

If the organic carbon content rate (%C _bio ) of the mathematical formula 1 thus derived is about 60% or more, the polylactic acid resin and the polylactic acid-polyamide alloy resin composition including the same include more content The resin and carbon from the biomass can properly display the unique environmental characteristics and biodegradability.

More specifically, the polylactic acid resin satisfying such a high organic carbon content (%C _bio ) and the polylactic acid-polyamide alloy resin composition including the polylactic acid resin can exhibit the following environmental characteristics.

Biochemical products such as polylactic acid resin are characterized by biodegradability and low carbon dioxide emissions. At the current technical level, compared with the use of petrochemical products, carbon dioxide emissions can be reduced to a maximum of 108%, and can be used for The energy to prepare the resin is reduced to at most 50% energy. In addition, if biomass plastics are used to produce bioplastics, the amount of carbon dioxide emissions calculated by ISO14000 compliant life cycle analysis (LCA) can be reduced by up to about 70% compared to fossil raw materials.

As a specific example, according to Nature Works, it is known that polylactic acid resin, one of bioplastics, produces only 0.77 kg of carbon dioxide per kg compared to 3.4 kg of carbon dioxide emitted per kg when manufacturing PET resin. The effect of% carbon dioxide is only 56% compared to PET in terms of energy usage. However, in the case of known polylactic acid resins, due to low flexibility However, it is limited in application. When adding other ingredients such as plasticizers to solve this problem, the advantages of the bioplastic will be greatly reduced.

However, when the polylactic acid resin and the polylactic acid-polyamide alloy resin composition containing the same satisfy the high organic carbon content (%C _bio ), not only can the advantages as a plastic be fully utilized, but also It can also solve the problems of low flexibility of polylactic acid resin, so it can be applied to various fields.

Therefore, the polylactic acid resin satisfying the high organic carbon content rate (%C _bio ) and the polylactic acid-polyamide alloy resin composition containing the same exhibit the advantages of being a plastic and show a significant reduction in carbon dioxide generation and energy use The amount of environmental protection characteristics. Such environmental protection characteristics can be measured by, for example, life cycle assessment of the polylactic acid-polyamide alloy resin composition.

In the polylactic acid-polyamide alloy resin composition, the ¹⁴ C isotope content of carbon atoms of the polylactic acid resin may be about 7.2×10 ^-11 to 1.2×10 ^-10 % by weight, and may be about 9.6× 10 ^-11 to 1.2×10 ^-10 % by weight, or may be about 1.08×10 ^-10 to 1.2×10 ^-10 % by weight. In the polylactic acid resin having such ¹⁴ C isotope content, more resin and carbon or substantially all of the resin and carbon can be derived from biomass, and can exhibit more excellent biodegradability and environmental protection characteristics.

The polylactic acid repeating unit of the hard segment of the polylactic acid resin may be derived from biomass, and the structural unit of the soft-linked polyolefin polyol may also be derived from biomass. The structural unit of such a polyolefin-based polyol can be obtained, for example, from a biomass-derived polyolefin-based polyol resin. The biomass can be any plant or animal resource, for example, it can be plant resources such as corn, sugar cane, or cassava flour. In this way, the polylactic acid resin containing the polyolefin-based polyol constituent unit derived from biomass and the polylactic acid-polyamide alloy resin composition containing it can exhibit a higher organic carbon content rate (%C _bio ), for example , Can show an organic carbon content rate (%C _bio ) of about 90% or more, or about 95% or more.

At this time, in the polylactic acid resin, the biomass-derived hard segment-derived biomass-derived organic carbon content ratio (% _Cbio ) defined by Mathematical Formula 1 may be about 90% or more, preferably about 95 % To 100%, the content of the organic carbon derived from biomass defined by the mathematical formula 1 from the soft segment of the biomass may be about 70%, preferably about 75% to 95%.

The polylactic acid resin contained in the polylactic acid-polyamide alloy resin composition has an organic carbon content rate from biomass of about 60% or more, or as high as about 80% or more, so it can be used for obtaining D6866-based certification-JBPA's "Biomass Pla" (Biomass Pla) certification standards, which can be given to JORA's "biomass-based (Biomass-based) label.

In the polylactic acid resin, the polylactic acid repeating unit represented by Chemical Formula 1 contained in the hard segment may be referred to as a polylactic acid homopolymer (homopolymer) or a repeating unit constituting the same. Such a polylactic acid repeating unit can be prepared by a method for preparing a polylactic acid homopolymer known to those of ordinary skill in the art. For example, cyclic 2-monomer L-lactide or D-lactide is produced from L-lactic acid or D-lactic acid, and then obtained by ring-opening polymerization, or it can be obtained by directly converting L-lactic acid or D-lactic acid Obtained by dehydration condensation. Among them, the polylactic acid repeating unit with a higher degree of polymerization can be obtained by the ring-opening polymerization method, so this method is preferably used. Furthermore, the polylactic acid repeating unit can be prepared by copolymerizing L-lactide and D-lactide at a certain ratio to exhibit amorphousness. However, in order to further improve the heat resistance of the molded product including the polylactic acid resin, Limited use of any of the L-lactide or D-lactide and preparation by homopolymerization. More specifically, L-lactide or D-lactide can be used with an optical purity of 98% or more Materials to undergo ring-opening polymerization to obtain the repeating unit of the polylactic acid, however, if the optical purity cannot reach this level, the melting temperature (Tm) of the polylactic acid resin will decrease.

In addition, the polyolefin-based polyol repeating unit contained in the soft segment of the polylactic acid resin may have the structural unit of the polyolefin-based polyol represented by the chemical formula 2 with a urethane bond (-C(=O) -NH-) or ester bond (-C(=O)-O-) is a medium and connected into a linear or branched structure. Furthermore, the constituent unit of the polyolefin polyol may be referred to as a polymer (poly(1,2-butadiene) or poly(1,3-butadiene) obtained by radical polymerization of monomers such as butadiene Diene)) or the constituent unit constituting it, in particular, may represent a liquid polybutadiene (HTPB) having a molecular weight of 1,000 to 5,000 obtained by adding a hydroxyl group at the end and hydrogenation reaction.

At this time, the pre-polymer with lactide and diisocyanate or two functional groups can be added and polymerized by adding hydroxyl groups at the ends of the polyolefin-based polyol constituent unit or to the hydroxyl groups at the end of the polyolefin-based polyol constituent unit The isocyanate compound above the group reacts to form the urethane bond. Furthermore, when the hydroxyl group at the end of the structural unit of the polyolefin polyol reacts with lactide or lactic acid derivative compound, an ester bond (-C(=O)-O-) can be formed. The polyolefin-based polyols are connected to each other to form a linear or branched chain using such urethane bonds or ester bonds as a medium, thereby forming a polyolefin-based polyol repeating unit.

The molar ratio of the hydroxyl group at the end of the polyolefin-based polyol constituent unit and the isocyanate group of the diisocyanate or the isocyanate compound of 2 or more functional groups may be 1:0.50 to 1:0.99. Preferably, the reaction molar ratio of the hydroxyl group: isocyanate group of the isocyanate compound terminal of the polyolefin-based polyol may be about 1:0.60 to about 1:0.95, more preferably about 1:0.70 to about 1:0.90 .

The polyolefin-based polyol constituent unit may be referred to as a urethane polyol repeating unit, and the polymer or the repeating unit composed of the linear unit formed by connecting urethane bonds as a medium may have a hydroxyl group at the terminal. Thus, the polyolefin-based polyol repeating unit can be used as an initiator in the polymerization process for forming the polylactic acid repeating unit. However, if the molar ratio of the hydroxyl group: isocyanate group exceeds 0.99 and is too high, the number of hydroxyl groups at the end of the repeating unit of the polyolefin polyol may be insufficient (for example: OHV<1) and it may not work It acts as a starter itself. Moreover, if the reaction molar ratio of the hydroxyl group: isocyanate group is too low, the number of hydroxyl groups at the terminal of the repeating unit of the polyolefin polyol is too large (OHV>35), making it difficult to obtain a high molecular weight polylactic acid repeating unit and Polylactic acid resin.

The polyolefin-based polyol repeating unit may have a number average molecular weight of about 1,000 to 100,000, and preferably may have a number average molecular weight of 10,000 to 50,000. If the molecular weight of the polyolefin polyol repeating unit is too large or too small, the molded product obtained from the polylactic acid resin and the polylactic acid-polyamide alloy resin composition including the same has flexibility and moisture resistance. Sexual or mechanical physical properties will be insufficient. Moreover, since it is difficult for the polylactic acid resin to satisfy proper molecular weight characteristics, the processability of the polylactic acid-polyamide alloy resin composition is reduced or the flexibility, moisture resistance, or mechanical physical properties of the molded product are reduced .

The isocyanate compound capable of bonding to the terminal hydroxyl group of the repeating unit of the polyolefin polyol to form a urethane bond may be a diisocyanate compound or a polyfunctional isocyanate compound having three or more isocyanate groups in the molecule, and may be derived from fossil fuels.

Examples of the diisocyanate compound include 1,6-hexamethylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, and 1,3-xylene diisocyanate. (1,3-xylenediisocyanate), 1,4-xylene diisocyanate, 1,5-naphthalene diisocyanate, isophthalic diisocyanate, p-phenylene diisocyanate, 3,3'-2 methyl-4,4'-di Toluene diisocyanate, 4,4'-bis-p-phenylene diisocyanate, hexamethylene isocyanate, isophorone diisocyanate or hydrogenated-xylene diisocyanate, etc. Furthermore, the polyfunctional isocyanate compound may be selected from the group consisting of an oligomer of the diisocyanate compound, a polymer of the diisocyanate compound, a cyclic polymer of the diisocyanate compound, and hexamethylene diisocyanate. Cyanurate (hexamethylene diisocyanate isocyanurate), other triisocyanate compounds and their isomer compounds. In addition, various diisocyanate compounds known to those of ordinary skill in the art can be used without limitation. Only in terms of imparting flexibility to the polylactic acid resin film and the like, 1,6-hexamethylene diisocyanate is preferably used.

In addition, the polylactic acid resin includes an intercalation in which the terminal carboxyl group of the polylactic acid repeating unit contained in the hard segment and the terminal hydroxyl group of the polyolefin-based polyol constituent unit contained in the soft segment are connected by an ester bond A segment copolymer, or the block copolymer may be a linear or branched block copolymer in which the block copolymer is connected using a urethane bond as a medium.

Specifically, in this block copolymer, the terminal carboxyl group of the polylactic acid repeating unit and the terminal hydroxyl group of the polyolefin-based polyol repeating unit may form an ester bond. For example, the chemical structure of this block copolymer can be expressed as the following general formula 1 or 2.

[General formula 1] Polylactic acid repeating unit (L)-(E)-polyolefin polyol repeating unit (O-U-O-U-O)-(E)-polylactic acid repeating unit (L)

[General formula 2] Polylactic acid repeating units (L)-(E)-Polyolefin-based polyol constituent units (O)-(E)-polylactic acid repeating units (L)-(U)-polylactic acid repeating units (L)-(E) -Polyolefin polyol constituting unit (O)-(E)-polylactic acid repeating unit (L)

In the general formulae 1 and 2, the O represents a polyolefin polyol structural unit, U represents a urethane bond, and E represents an ester bond.

As such, the polylactic acid resin can suppress the polyolefin-based polyol used to impart the flexibility along with the block copolymer including the polylactic acid repeating unit and the polyolefin-based polyol constitutional unit or the repeating unit. The overflow of constituent units, repeating units, etc., and the molded article obtained therefrom can have various physical properties such as excellent moisture resistance, transparency, mechanical physical properties, heat resistance, or block resistance. Moreover, as at least a part of the polylactic acid constituent unit or repeating unit and the polyolefin-based polyol repeating unit take the form of a block copolymer, the molecular weight distribution, glass transition temperature (Tg) and melting of the polylactic acid resin The temperature (Tm) and the like are optimized to improve the mechanical physical properties, flexibility and heat resistance of the molded product.

However, all the repeating units of the polylactic acid contained in the polylactic acid resin need not be in the form of a block copolymer combined with the polyolefin-based multiple structural units or repeating units, and the At least a part may be in the form of a polylactic acid homopolymer that is not bound to the polyolefin-based polyol structural unit or repeating unit. In this case, the polylactic acid resin may be the terminal carboxyl group of the polylactic acid repeating unit contained in the hard segment and the terminal hydroxy group of the polyolefin-based polyol constituent unit contained in the soft segment to The block copolymer linked by an ester bond, or the block copolymer connected to a linear or branched chain block using a urethane bond as a medium further includes the polyene The polylactic acid repeating unit in which the hydrocarbon polyol repeating unit is combined, that is, further includes a mixture of polylactic acid homopolymers.

In addition, the total weight of the polylactic acid resin is 100 parts by weight (when the weight of the block copolymer optionally includes a polylactic acid homopolymer, the total weight of these homopolymers is 100 parts by weight) The polylactic acid resin may include about 65 to 95 parts by weight, about 80 to 95 parts by weight, or about 82 to 92 parts by weight of hard segments and about 5 to 35 parts by weight, about 5 to 20 parts by weight, or about 8 to 18 parts by weight of soft segments.

If the content of the soft segment is too high, it is difficult to provide a high-molecular-weight polylactic acid resin, which may result in a decrease in mechanical and physical properties such as the strength of the molded product including the same. In addition, the glass transition temperature is lowered, which may result in a decrease in slipping, handling, and shape maintenance characteristics during packaging processing using molded products. Conversely, if the content of the soft segment is too low, the improvement of the flexibility or moisture resistance of the polylactic acid resin and the molded product of the polylactic acid is restricted. In particular, if the glass transition temperature of the polylactic acid resin rises too high, it may cause The flexibility of the molded product is reduced, and the structural unit or repeating unit of the polyolefin polyol in the soft segment is difficult to function well as an initiator, resulting in a decrease in polymerization conversion rate or failure to prepare a high molecular weight polylactic acid resin.

The polylactic acid resin may have a number average molecular weight of about 50,000 to 200,000, and preferably may have a number average molecular weight of about 50,000 to 150,000. Moreover, the polylactic acid resin may have a weight average molecular weight of about 100,000 to 400,000, and preferably may have a weight average molecular weight of about 100,000 to 320,000. This molecular weight may affect the processability of the polylactic acid-polyamide alloy resin composition or the mechanical physical properties of the molded product. When the molecular weight is too small, when melt processing is performed by extrusion or other methods, the melt viscosity is too low, which will reduce the processability of molded products, even if it can be processed into molded products, strength, etc. Mechanical physical properties may be reduced. Conversely, when the molecular weight is too large, the melt viscosity during melt processing is too high, which greatly reduces the productivity and processability as a molded product.

In addition, the molecular weight distribution (Mw/Mn) of the polylactic acid resin defined by the ratio of the weight average molecular weight (Mw) of the log average molecular weight may be about 1.60 to 3.0, and preferably may be about 1.80 to 2.15. Since the polylactic acid resin exhibits such a narrow molecular weight distribution, it can exhibit proper melt viscosity or melt characteristics when melt-processed by methods such as extrusion, and can exhibit the excellent extrusion state of the molded product or Processability, and a molded article including the polylactic acid resin can exhibit excellent mechanical and physical properties such as strength. However, when the molecular weight distribution is too narrow, the melt viscosity is too high at the processing temperature required for extrusion, so it may be difficult to process into a molded product. Conversely, when the molecular weight distribution is too wide, the mechanical properties such as the strength of the molded product decrease or the melt viscosity is too small, and the melt characteristics are poor. Therefore, it is difficult to mold or the molding extrusion state is poor.

In addition, the melting temperature (Tm) of the polylactic acid resin may be about 145-178°C, about 160-178°C, or about 165-175°C. If the melting temperature is too low, the heat resistance of the molded product including polylactic acid resin may be reduced; if the melting temperature is too high, high temperature or high viscosity is required for melt processing by extrusion or the like, which may cause the molded product, etc. Processing characteristics deteriorate.

In addition, the polylactic acid resin, for example, the block copolymer contained therein may have a glass transition temperature (Tg) of about 20 to 55°C, or 25 to 55°C, or 30 to 55°C. Since the polylactic acid resin exhibits such a glass transition temperature range, it is possible to appropriately maintain the flexibility or stiffness of the molded product including the polylactic acid-polyamide alloy resin composition, so that it can be optimized Use as a molded product. If the glass transition temperature of the polylactic acid resin is too low, although the flexibility of the molded product will be improved, as the strength becomes too low, it may lead to processing using the molded product The slipping (slipping), handling, shape maintenance, and resistance to agglomeration are not suitable, and the applicability as a molded product may not be suitable. Conversely, if the glass transition temperature is too high, the flexibility of the molded product is low and the strength is too high, so that when the molded product is assembled, the adhesion to the object product may become poor.

In addition, the polylactic acid-polyamide alloy resin composition may contain less than about 1% by weight of monomers based on the weight of the polylactic acid resin contained therein (for example, used for manufacturing polylactic acid repeating units (Lactide monomers, etc.), preferably 0.01 to 0.5% by weight of monomers may remain. Since the polylactic acid-polyamide alloy resin composition includes a block copolymer having specific structural characteristics and a polylactic acid resin and an antioxidant including the same, most of the lactide monomers used in the preparation process participate Polymerization forms a polylactic acid repeating unit, and substantially no depolymerization or decomposition of the polylactic acid resin occurs. Therefore, the polylactic acid-polyamide alloy resin composition may include a minimum amount of residual monomers, for example, residual lactide monomers and the like.

If the content of residual monomers in the composition is about 1% by weight or more, odor problems may occur during molding processing using the polylactic acid-polyamide alloy resin composition, and the molecular weight of the polylactic acid resin due to molding processing The reduction may lead to a decrease in the strength of the final molded product. In particular, when applied to food packaging products, residual monomers may overflow and may cause safety problems.

(B) Polyamide resin

The polyamide resin contained in the polylactic acid-polyamide alloy resin composition of the present invention functions to enhance the physical properties of the polylactic acid resin. For example, in order to maximize physical properties such as impact strength, rigidity, durability, heat resistance, and the like of the polylactic acid resin, the polyamide resin may be a high-rigidity polymer having a polyamide resin as a main component. The polyamidoamine resin may be PA6, PA66, PA11, PA46, PA12, PA1012, PA610, PA69, PA6T, PA6I, PA10T, PA12I, polyphthalamide (PPA), polyhexamethylene diamide Xylylenediamine (Poly-m-xylene-adipamide, PA MXD 6) or their mixtures or copolymers.

Specific examples of the polyamide resin include polycapramide (nylon 6), polytetramethylene adipamide (nylon 46), and polyhexamethylene hexamethylene diamide Polyhexamethylene adipamide (nylon 66), polyhexamethylene nonanediamide (nylon 69), polyhexamethylene sebacamide (nylon 610), polyhexamethylene sebacamide/nylon Methylene hexamethylene diamide (nylon 6/nylon 66), polyhexamethylene dodecanediamide (polyhexamethylene dodecanediamide), polyhexamethylene dodecanediamide (polyhexamethylene dodecamide) (nylon 612) , Polyundecanoamide (nylon 11), polydodecamide (nylon 12), polyhexamethylene isophthalamide (nylon 61), polyhexamethylene Polyhexamethylene terephthalamide/polyhexamethylene terephthalamide copolymer (nylon 6T/6I), polyhexamethylene terephthalamide/polyhexamethylene terephthalamide Amine copolymer (nylon 66/6T), polydodecane bis(4-aminocyclohexyl) methane (nylon PACM12), polyundecamethylene undecane diamine (polyundecamethylene terephthalamide) (nylon 11T), Polyhexahydroterephthalamide (polyundeca methylenehexahydro terephthalamide) (nylon 11T (H)) and so on. (At this time, I represents isophthalic acid and T represents terephthalic acid). These compounds may be used alone or as a mixture or copolymer of two or more.

More preferably, the polyamide resin may be selected from PA6, PA610, PA1010, PA1012, these mixtures and copolymers using monomers derived from biomass, and more preferably, PA1010 may be used.

The viscosity coefficient (viscosity number; ISO307) of the polyamide resin is preferably 120 to 220, and more preferably 120 to 160. When the viscosity coefficient (ISO307) is within the above range, the polyamide resin has a low melt viscosity, can be effectively melt-mixed with the polylactic acid resin, and can be more excellent in terms of balance between moldability, heat resistance, and mechanical physical properties.

The polyamide resin and the polylactic acid resin together form the matrix of the composition of the present invention. Based on the weight of the polylactic acid-polyamide alloy resin composition, the content of the polyamide resin may be 10 to 70% by weight, preferably 30 to 60% by weight, and may be more excellent in the range Compatibility with polylactic acid resin, heat resistance, appearance characteristics and impact strength.

The polylactic acid-polyamide alloy resin composition may further include an impact modifier.

The impact modifier may be selected from polyamide copolymer impact modifier, acrylic impact modifier, methyl methacrylate-butadiene-styrene (MBS) impact modifier, styrene -One or more of ethylene-butadiene-styrene (SEBS) impact modifiers, silicone impact modifiers and polyester elastomer impact modifiers, preferably polyamide copolymer impact modification The agent is more preferably a polyether polyol-polyamide copolymer.

The compatibility between the polyether polyol-polyamide copolymer and the polyamide and the impact resistance exhibited are excellent and economical, and have excellent elasticity, flexibility and impact resistance. Preferably, the biomass raw material is used to prepare the polyether polyol-polyamide copolymer.

The polylactic acid resin in the polylactic acid-polyamide alloy resin composition of the present invention is introduced into the polymer structure of the polylactic acid resin due to the introduction of the polyolefin-based polyol component, so that it is copolymerized with the polyamide resin as an impact modifier, acrylic Impact modifier, methyl methacrylate-butadiene-styrene (MBS) impact modifier, styrene-ethylene-butadiene-styrene (SEBS) impact modifier, silicone impact change Either the sex agent or the polyester-based elastomer impact modifier exhibits excellent compatibility. Therefore, the specific impact modifier is not limited.

Based on a total of 100 parts by weight of the polylactic acid resin and the polyamide resin, 20 parts by weight of the impact modifier is included, preferably 0.1 to 20 parts by weight, and more preferably 5 to 10 parts by weight.

Within the above range, it has an excellent compatibility with polylactic acid resin and polyamide resin, and has the effect of greatly improving the impact resistance, elongation and heat resistance of the prepared polylactic acid-polyamide alloy resin composition. Since the impact modifier reduces the crystallization rate and crystallization content of the polylactic acid-polyamide alloy resin composition, thereby reducing heat resistance and injection moldability, the amount of the impact modifier exceeds 20% by weight At this time, there is a problem that the heat resistance and the appearance of the injection-molded product will decrease.

In addition, the polylactic acid-polyamide alloy resin composition may include an antioxidant. The antioxidant suppresses the yellowing of the polylactic acid resin, which can improve the appearance of the polylactic acid-polyamide alloy resin composition and the molded product, and can suppress the oxidation or thermal decomposition of the soft segment.

To this end, the polylactic acid-polyamide alloy resin composition may include about 100 to about 100 to the weight of a monomer (for example, lactic acid or lactide) used for molding the polylactic acid repeating unit of the polylactic acid resin. Antioxidants at a level of 3,000 ppmw, about 100 to 2,000 ppmw, about 500 to 1,500 ppmw, or about 1,000 to 1,500 ppmw.

When the content of the antioxidant is too low, flexible components such as the soft segment are oxidized to yellow the polylactic acid resin, and the polylactic acid-polyamide alloy resin composition and molded product bad apperance. On the contrary, when the content of the antioxidant is too high, the antioxidant will reduce the polymerization rate of lactide and the like, and the normal generation of the hard segment including the polylactic acid repeating unit may not be normal, and the polylactic acid resin may be reduced Mechanical physical properties.

When an appropriate amount of antioxidant is included, for example, when the appropriate amount of the antioxidant is added during the preparation of the polylactic acid resin to obtain the polylactic acid resin and the polylactic acid-polyamide alloy resin composition, the polylactic acid resin can be improved The degree of polymerization (conversion of polymerization) and degree of polymerization (degree of polymerization) can expand productivity. Moreover, in a molding process in which the polylactic acid-polyamide alloy resin composition needs to be heated to 180°C, the polylactic acid-polyamide alloy resin composition can exhibit excellent stability, and thus can suppress the production of lactide Or monomers such as lactic acid, or low-molecular substances that can suppress the formation of a chain of cyclic oligomers.

Therefore, as a result of the reduction of the molecular weight of the polylactic acid resin or the color change (yellowing) of the molded product, etc., it is possible to provide not only an excellent appearance, but also a greatly improved flexibility, and excellent mechanical properties Molded products with various physical properties such as properties, heat resistance, and block resistance.

In particular, the polylactic acid-polyamide alloy resin composition may have an ester repeating unit, and by adding an antioxidant, a thermal stabilizer, or a polymerization stabilizer, etc., when the ester repeating unit is subjected to high-temperature polymerization reaction, During high-temperature extrusion processing or molding, the phenomenon of oxidation or thermal decomposition is suppressed.

One or more kinds selected from hindered phenol antioxidants, amine antioxidants, thio antioxidants and phosphite antioxidants may be used as the antioxidants, or known ones may be used It can be used for various antioxidants of polylactic acid-polyamide alloy resin composition.

Specific examples of these antioxidants include phosphoric acid thermal stabilizers such as phosphoric acid, trimethyl phosphate, and triethyl phosphate; 2,6-2-tert-butyl p-cresol, octadecyl-3-(4-hydroxy- 3,5-di-tert-butylbenzene Group) propionate, tetrabis[methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] methane, 1,3,5-trimethyl-2, 4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, 3,5-di-tert-butyl-4-hydroxybenzyl diphosphite, 4,4 -Butenylene-bis-(3-methyl-6-tert-butylphenol), 4,4'-thiobis(3-methyl-6-tert-butylphenol) and bis[3,3'- Bis-(4'-hydroxy-3'-tert-butyl-phenyl)butanoic acid] ethylene glycol esters and other sterically hindered phenols primary antioxidants; phenyl-α-naphthylamine, phenyl-β-naphthalene Amine, N,N'-diphenyl-p-phenylene diamine and N-N'-di-β-naphthyl-p-phenylene diamine and other secondary antioxidants; dilauryl disulfate (dilauryl diSulfate), dilaurylthiopropionate, distearyl thiopropionate, distearyl thiopropionate, mercaptobenzothiazole and tetramethylthiuram disulfide Alkyl thio) propionate] methane (tetramethyl thiuram disulfide tetrabis [methylene-3- (laurylthio) propionate] methane) and other thio (thio) secondary antioxidants; and triphenyl phosphite, trinonyl Phenyl phosphite, triisodecyl phosphite, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite and (1,1'-biphenyl)-4,4'- Bis-yl bisphosphite tetra[2,4-bis(1,1-dimethylethyl)phenyl] ester ((1,1'-biphenyl)-4,4'-diylbisphosphonous acid tetrakis[2,4 -bis(1,1-dimethyl ethyl)phenyl]ester) and other phosphorous acid secondary antioxidants. Among them, it is preferable to use a phosphorous acid antioxidant in combination with other antioxidants.

In addition to the impact modifiers and antioxidants described above, the polylactic acid-polyamide alloy resin composition may include various well-known hydrolysis resistance agents, nucleating agents, organic compounds without impairing its effect Or inorganic fillers, plasticizers, chain extenders, ultraviolet stabilizers, coloring inhibitors, matte glazes, deodorants, flame retardants, weathering agents, antistatic agents, release agents, antioxidants , Ion exchangers, color pigments, inorganic or organic particles and other additives.

The hydrolysis-resistant polylactic acid is a reactive compound that can react with a hydroxyl or carboxyl group of the terminal component of polylactic acid, which not only improves the hydrolysis resistance of the polylactic acid resin-polyamide resin composition but also improves durability. That is, the hydrolysis-resistant agent is suitable for resins such as polyester, polyamide, polyurethane, etc., thereby performing an endcapping at the end of the polymer chain to prevent hydrolysis of the resin composition by water or acid effect. The hydrolysis resistant agent may be a carbodiimide compound, for example, modified phenylcarbodiimide, poly(tolylcarbodiimide), poly(4,4'-diphenylmethanecarbodiimide ), poly(3,3'-dimethyl-4,4'-biphenylcarbodiimide), poly(p-phenylenecarbodiimide), poly(m-methylenecarbodiimide) , Poly (3,3'-dimethyl-4,4'-diphenylmethane carbodiimide). The hydrolysis resistant agent may be added within 5 wt% based on the total weight of the polylactic acid resin and the polyamide resin.

Based on the total weight (including nucleating agent) of the polylactic acid-polyamide alloy resin composition, the nucleating agent may be included within 10% by weight, and preferably within 5% by weight. Within the above range, more improved heat resistance and injection moldability can be achieved. As the nucleating agent, a sorbitol-based metal salt, a phosphite-based metal salt, quinacridone, calcium carboxylate, an amide-based organic compound, or the like can be used. Preferably, a phosphite-based metal salt can be used as the nucleating agent. Said nucleating agent.

Examples of the plasticizer include phthalate plasticizers such as diethyl phthalate, dioctyl phthalate, and dicyclohexyl phthalate; di-1-butane adipate Group, adipic acid di-n-octyl, sebacic acid-n-butyl, azelaic acid-2-ethylhexyl and other aliphatic dibasic acid ester plasticizers; diphenyl 2-ethylhexyl phosphate, Phosphate plasticizers such as diphenyloctyl phosphate; hydroxy polyvalent carboxylic acid esters such as tributyl acetyl citrate, tri-2-ethyl octyl acetyl citrate, tributyl citrate Plasticizer; fatty acid ester plasticizers such as acetyl ricinoleic acid methyl and stearic acid amyl; glycerin triacetic acid Polyvalent alcohol ester plasticizers such as esters; epoxy-based plasticizers such as epoxidized soybean oil, epoxidized linseed oil, fatty acid butyl ester, epoxy octyl stearate, etc.

In addition, the color pigments include inorganic pigments such as carbon black, titanium oxide, zinc oxide, iron oxide; anthocyanins, phosphorus, quinones, perinones, isoindolinones, sulfur Organic pigments such as indigo.

In addition, when the molded product is prepared using the polylactic acid-polyamide alloy resin composition, in order to improve the mold irregularity of the prepared molded product, inorganic or organic particles may be included. Based on the total weight of the polylactic acid-polyamide alloy resin composition, it may include the inorganic or organic particles within 30% by weight, and preferably includes the inorganic or organic particles within 10% by weight. Examples of the inorganic or organic particles include silica, colloidal silica, alumina, alumina sol, talc, titanium dioxide, mica, calcium carbonate, polystyrene, and polymethacrylate , Silicone, etc.

The silica, titania, or talc is not limited to surface treatment or not. However, when surface-treated titania or talc is used, not only is the overall balance of physical properties including rigidity and impact strength excellent, but also the specific gravity is reduced and the heat resistance and injection molding The effect of improved formability. The surface treatment can be specifically carried out by chemical or physical methods using treatment agents such as silane coupling agents, higher fatty acids, fatty acid metal salts, unsaturated fatty acids, organic titanates, resin acids, and polyethylene glycol. The average particle size of the inorganic particles may be 1 to 30 μm, preferably 1 to 15 μm, and within the above range, there is an effect of further improving heat resistance and rigidity.

In addition, it may also include various known additives that can be used in the polylactic acid-polyamide alloy resin composition or its molded product, and its specific types and methods of obtaining are obvious to those of ordinary skill in the art.

In addition, in the polylactic acid-polyamide alloy resin composition, in a wafer state, the color-b (color-b) value may be less than 15, preferably 10 or less. The polylactic acid-polyamide alloy resin composition includes an antioxidant and can suppress yellowing of the polylactic acid resin, so that it can exhibit a color-b value of less than 15. If the color-b value of the polylactic acid-polyamide alloy resin composition is 15 or more, when used for molding purposes, the appearance of the molded product is poor, resulting in a decrease in the value of the product.

Next, the method for preparing the polylactic acid-polyamide polymer alloy resin composition of the present invention will be specifically described.

<Preparation of polyolefin polyol constituent units>

First, add hydroxyl groups to the end of the polymer (poly(1,2-butadiene) or poly(1,3-butadiene) obtained by radical polymerization of butadiene monomer, and form it by hydrogenation reaction Hydroxyl-erminated polybutadiene (HTPB) with a molecular weight in the range of 1,000 to 3,000, to obtain a (co)polymer having polyolefin-based polyol constituent units. It can be obtained by commonly used polyolefin-based polyol (co) The preparation method of the polymer is carried out.

<Preparation of Polyolefin-based Polyol Repeating Unit A>

Next, the (co)polymer having the polyolefin-based polyol constituent unit, the polyfunctional isocyanate compound, and the urethane reaction catalyst are filled in the reactor, and heated and stirred to perform the urethane reaction. By this reaction, two or more isocyanate groups of the isocyanate compound and terminal hydroxyl groups of the (co)polymer are combined to form an urethane bond. As a result, it is possible to form a (co)polymer having a polyolefin-based polyol constituent unit connected to a linear or branched polyurethane polyol repeating unit using the urethane bond as a medium. It is included in the polylactic acid resin as a soft segment of the polylactic acid resin. At this time, the polyurethane polyol (co)polymer may be formed into a polyolefin-based polyol structural unit (O) to The urethane bond (U) is used as a medium and combined in the form of O-U-O-U-O or O-U(-O)-O-U-O to form a linear or branched type with polyolefin-based polyol constituent units at both ends.

<Preparation of Polyolefin-based Polyol Repeating Unit B>

In addition, a (co)polymer having the polyolefin-based polyol constituent unit, a lactic acid (D- or L-lactic acid) or lactide (D- or L-lactide) compound, and a polycondensation reaction catalyst or ring-opening reaction The catalyst is added to the reactor, and heated and stirred to perform polyester reaction or ring-opening polymerization reaction. Through this reaction, the lactic acid (D- or L-lactic acid) or lactide (D- or L-lactide) and the terminal hydroxyl group of the (co)polymer are combined to form an ester bond. As a result, a polyolefin-based polyol constitutional unit can be formed into a linear or branched (co)polymer with the polylactic acid repeating unit using the ester bond as a medium. At this time, the (co)polymer can be formed as a polyolefin polyol structural unit (O) using an ester bond (E) as a medium and a polylactic acid repeating unit (L) in the form of LEOEL to form a linear type and two Each terminal has the form of a polylactic acid repeating unit.

After that, two or more isocyanate groups of the isocyanate compound are combined with the terminal hydroxyl group of the (co)polymer to form a urethane bond (U), and in the form of LEOELULEOEL is combined into a linear or branched type to prepare a poly Lactic acid resin.

In this case, the polyolefin-based polyol repeating unit obtained from butadiene can be formed from biomass-derived substances such as plant resources, and thus, the biomass-derived organic carbon in the polyolefin-based polyol (co)polymer The content rate (%C _bio ) can be a higher value, which can be about 70% or more.

The urethane reaction can be carried out in the presence of commonly used tin-based catalysts, for example, stannous octoate, dibutylhltin dilaurate, dioctyltin dilaurate, and the like. Moreover, the urethane reaction can be used to prepare Prepared under normal reaction conditions of polyurethane resin. For example, after adding an isocyanate compound and a polyolefin polyol (co)polymer in the presence of nitrogen, the urethane reaction catalyst is added and reacted at 70 to 80°C for 1 to 5 hours to be prepared (Co)polymer having repeating units of polyolefin polyol.

Next, if in the presence of a (co)polymer having the polyolefin polyol repeating unit and an antioxidant, polycondensation reaction of lactic acid (D- or L-lactic acid) is carried out, or lactide (D- or L-cross Ester) ring-opening polymerization, the block copolymer (or polylactic acid resin including the same) can be prepared. That is, if this polymerization reaction is performed, the phenomenon of yellowing due to the oxidation of the soft segment can be suppressed by the antioxidant, so that the polylactic acid resin formed with the polylactic acid repeating unit including the hard segment can be prepared. At this time, at least A part of the polylactic acid repeating unit is bonded to the polyurethane polyol repeating unit at the end to form a block copolymer.

In addition, after preparing a prepolymer in which a polyolefin polyol and a lactide are combined, a known polylactic acid-based copolymer having a chain extension form obtained by treating these prepolymers with a diisocyanate compound can be formed Or, a known branched block copolymer obtained by reacting the prepolymer with an isocyanate compound having two or more functional groups may be formed. In addition, the lactide ring-opening polymerization reaction may be performed in the presence of a metal catalyst including alkaline earth metals, rare earth metals, transition metals, aluminum, germanium, tin, antimony, or the like. Specifically, the metal catalyst may be in the form of carboxylate, alkoxide, halide, oxide, carbonate, etc. thereof. Preferentially, tin octoate, titanium tetraisopropoxide, aluminum triisopropoxide and the like are used as the metal catalyst.

In addition, the step of forming a polylactic acid repeating unit such as the lactide ring-opening polymerization reaction may be continuously performed in the same reactor in which the urethane reaction is performed. That is, polyolefin polyol After the compound and the isocyanate compound undergo a urethane reaction to form a polymer having a polyolefin-based polyol repeating unit, monomers such as lactide, a catalyst, and the like are continuously added in such a reactor to form a polylactic acid repeating unit. As a result, the polymer having a polyolefin-based polyol repeating unit functions as an initiator, so that the polylactic acid repeating unit and the polylactic acid resin including the same can be continuously prepared with high productivity and productivity. In the same way, after the ring-opening polymerization using polyolefin polyol as the lactide starter, the isocyanate compound is continuously added in the same reactor to conduct chain-growth polymerization, so that the yield and productivity can be continuously prepared The repeating unit of polylactic acid and the polylactic acid resin including the same.

The polylactic acid resin thus prepared can be mixed with a polyamide resin and other materials to prepare a polylactic acid-polyamide alloy resin composition.

The polylactic acid-polyamide alloy resin composition includes a specific block copolymer (polylactic acid resin) combined with a hard segment and a soft segment, thereby not only showing the biodegradability of the polylactic acid resin, but also showing The improved flexibility. Moreover, the overflow of soft segments for additional flexibility can be minimized, and the moisture resistance, mechanical physical properties, heat resistance, transparency, or haze value characteristics of the molded product can be greatly reduced according to the addition of such soft segments And so on.

In addition, the polylactic acid resin has a predetermined glass transition temperature and optionally has a predetermined melting temperature, so that the obtained molded product and the like not only exhibit optimal flexibility and rigidity as a packaging material, but also are melt-processed The properties are also excellent, and the resistance to agglomeration and heat resistance are further improved. Therefore, such a polylactic acid resin and the polylactic acid-polyamide alloy resin composition including the same are preferably used as packaging materials such as molded articles.

In addition, the polylactic acid resin and the antioxidant are included together, so that yellowing during preparation or use can be suppressed, and the polylactic acid-polyamide alloy resin composition including these components can Provided is a molded product that not only has excellent appearance and commodities, but also exhibits various physical properties such as improved flexibility and outstanding mechanical and physical properties.

That is, the polylactic acid-polyamide alloy resin composition of the present invention includes a polyolefin-based polyol in a soft segment, and thus the flexibility of a molded product prepared using the polylactic acid-polyamide alloy resin composition can be greatly improved .

In addition, unlike the repeating unit of polylactic acid which is a hard segment, the repeating unit of a polyolefin polyol of a non-polar soft segment reduces the water content in the entire resin, thereby greatly improving the moisture resistance.

In the following, the action and effect of the invention will be described in more detail through specific embodiments of the invention. These embodiments are only presented as examples of the invention, and the scope of rights of the invention is not limited thereto.

The raw materials used in the following examples and comparative examples are as follows.

1. Polyolefin polyol repeating units and their corresponding substances

-HTPB 1.0: Add hydroxyl groups to the end of the polymer (poly(1,2-butadiene) or poly(1,3-butadiene) obtained by radical polymerization of butadiene monomer, and hydrogenate Hydroxyl-erminated polybutadiene (HTPB) with a molecular weight of 1,000

-HTPB 2.0: Add hydroxyl groups to the end of the polymer (poly(1,2-butadiene) or poly(1,3-butadiene) obtained by radical polymerization of butadiene monomer, and hydrogenate Liquid polybutadiene (HTPB) with a molecular weight of 2,000

-HTPB 3.0: Add a hydroxyl group to the end of a polymer (poly(1,2-butadiene) or poly(1,3-butadiene) obtained by radical polymerization of butadiene monomer, and hydrogenate Liquid polybutadiene with molecular weight of 3,000 (HTPB)

-HTPB 5.0: Add hydroxyl groups to the end of the polymer (poly(1,2-butadiene) or poly(1,3-butadiene) obtained by radical polymerization of butadiene monomer, and hydrogenate Liquid polybutadiene with molecular weight of 5,000 (HTPB)

-PTMG 3.0: Polytetrahydrofurandiol; number average molecular weight is 3,000

-PPDO 2.4: poly(1,3-propanediol); number average molecular weight is 2400

-PBSA 11.0: aliphatic polyester polyol made from 1,4-butanediol and succinic acid and adipic acid; number average molecular weight is 11,000

2. Diisocyanate compounds and isocyanate compounds with more than 3 functional groups

-HDI: hexamethylene diisocyanate

-TDI: 2,4- or 2,6-toluene diisocyanate (toluene diisocyanate: TDI)

-D-L75: Bayer polyurethane adhesive (desmudur) L75 (trimethylolpropane + dimethylbenzene diisocyanate)

3. Lactide monomer

-L-lactide or D-lactide: Purac company, optical purity 99.5% or higher (only monomers composed of organic carbon derived from biomass)

4. Antioxidants, etc.

-TNPP: tris(nonylphenyl) phosphite

-U626: bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite

-S412: Tetra[methane-3-(laurylthio) propionate] methane

-PEPQ: (1,1'-biphenyl)-4,4'-di-yl bisphosphite tetra[2,4-bis(1,1-dimethylethyl)phenyl] ester

-I-1076: Octadecyl-3-(4-hydroxy-3,5-di-tert-butylphenyl) propionate

-O3: Bis[3,3'-bis-(4'-hydroxy-3'-tert-butyl-phenyl)butanoic acid] glycol ester

5. Polyamide resin, etc.

-PA1010: Polyamide resin made by polycondensation reaction of 1,10-decyldiamine and 1,10-sebacic acid from biomass, with a viscosity coefficient of 120cm ³ /g, The biological content is 100%

-PA610: Polyamide resin made by polycondensation reaction of petroleum-based 1,6-hexamethylenediamine and 1,10-sebacic acid derived from biomass, viscosity coefficient (viscosity number) 160cm ³ /g, biological content 63%

-PA66: Polyamide resin made by polycondensation reaction of petroleum-based 1,6-hexamethylenediamine and 1,6-adipic acid, viscosity coefficient is 200cm ³ /g, biological content is 0%

6. Impact modifier, etc.

-Pebax 63R53 SP01: poly(1,3-propanediol)-polyamide block copolymer, Arkema company, hardness is 56HD (Shore D (Shore D), 15s), biological content is 80%

-AX8840: Ethylene-maleic anhydride graft-glycidyl methacrylate copolymer, Arkema, grafting rate 8.0%

-Biostrength 150: acrylic core-shell impact modifier, Arkema

7. Inorganic filler and nucleating agent, etc.

-SP-3000: Talc, Darwin Chemical Co., Ltd., the average fineness is 2.5μm, and the proportion is 0.32g/cm ²

-EMforce ^TM Bio: CaCO ₂ , Specialty Minerals, with an average fineness of 1.0 μm and an average aspect ratio of 5.4

-TF-1: N,N',N"-tricyclohexyl-1,3,5-benzenetrimethylamide, NJC Corporation

-NA-11: Sodium 2,2'-methylenebis(4,6-di-tert-butylphenol) phosphate, Asahi Denka Corporation

8. Hydrolysis resistance and chain extender

-BioAdimide 100: carbodiimide polymer, Rhein Chemie

-ADR 4368: Styrene-acrylic polymer, BASF

Preparation Examples 1 to 6: Preparation of polylactic acid resins A to F

Into an 8L reactor equipped with a nitrogen introduction tube, a stirrer, a catalyst inlet, an outflow condenser, and a vacuum system, reactants with the components and contents shown in Table 1 below are added together with the catalyst. Dibutyltin dilaurate, which was 130 ppmw based on the total reactant content, was used as the catalyst. In nitrogen The urethane reaction was carried out at a temperature of 70°C for 2 hours under a stream of gas, and then 4Kg of L-(or D-) lactide was added for 5 times of nitrogen flushing.

After that, the temperature was raised to 150°C to completely dissolve the L-(or D-) lactide, and the tin 2-ethylhexanoate was diluted with 500 ml of toluene to obtain a catalyst with a total reactant content of 120 ppmw, and the catalyst was added through the catalyst inlet. The catalyst is added. The reaction was carried out at a temperature of 185°C for 2 hours under a pressurized state of 1 kg of nitrogen, and 200 ppmw of phosphoric acid was added through the catalyst inlet and mixed for 15 minutes to passivate the residual catalyst. Next, a vacuum reaction is performed up to 0.5 torr to remove unreacted L-(or D-) lactide (approximately 5% by weight of the initial addition amount). And the molecular weight characteristics, Tg, Tm and %C _{of the} obtained resin were measured and shown in Table 1.

Preparation Example 7: Preparation of polylactic acid resin G

Into an 8L reactor equipped with a nitrogen introduction tube, agitator, catalyst inlet, outflow condenser and vacuum system, add 2.0865g of HTPB and 3.9kg of L-lactide and 0.1kg of D as shown in Table 1 below -Lactide and perform 5 nitrogen flushes. The temperature was raised to 150°C to completely dissolve the lactide, and 120 ppmw of tin 2-ethylhexanoate was diluted with 500 ml of toluene to obtain a catalyst, and the catalyst was added through the catalyst inlet. Next, the reaction was carried out at a temperature of 185°C for 2 hours under a pressurized state of 1 kg of nitrogen, and 200 ppmw of phosphoric acid was added through the catalyst inlet and mixed for 15 minutes to passivate the remaining catalyst. Next, a vacuum reaction is performed up to 0.5 torr to remove unreacted L-(or D-) lactide (about 5 parts by weight of the initial addition amount). After that, the HDI and dibutyltin disilicate catalyst shown in Table 1 were diluted with 500 ml of toluene and added to the reaction vessel. The reaction was carried out at a temperature of 190° C. for 1 hour under a nitrogen atmosphere, and the molecular weight characteristics, Tg, Tm, and %C _{of the} obtained resin were measured and shown in Table 1.

Preparation Example 8: Preparation of polylactic acid resin H

Using 2.0885g of HTPB and 3.8kg of L-lactide and 0.2kg of D-lactide as shown in Table 1 below, HDI and D- were added together through the catalyst addition port as shown in Table 1 Except for L75, the same preparation method as Preparation Example 7 was used. And the molecular weight characteristics, Tg, Tm and %C _{of the} obtained resin were measured and shown in Table 1.

Preparation Example 9: Preparation of polylactic acid resin I

Into an 8L reactor equipped with a nitrogen introduction tube, stirrer, catalyst inlet, outflow condenser and vacuum system, add 3.03869g of PTMG and 4kg of L-lactide as shown in Table 1 below and perform 5 times of nitrogen rinse. The temperature was raised to 150°C to completely dissolve the L-lactide, and 120 ppmw of tin 2-ethylhexanoate catalyst was diluted with 500 ml of toluene and added as a catalyst to the reaction vessel through the catalyst inlet. Next, the reaction was carried out at a temperature of 185° C. for 2 hours under a pressurized state of 1 kg of nitrogen, and 200 ppmw of phosphoric acid was added through the catalyst inlet and mixed for 15 minutes to passivate the remaining catalyst. Next, a vacuum reaction is performed up to 0.5 torr to remove unreacted L-lactide. And the molecular weight characteristics, Tg, Tm and %C _{of the} obtained resin were measured and shown in Table 1.

Preparation Example 10: Preparation of polylactic acid resin J

Into an 8L reactor equipped with a nitrogen introduction tube, stirrer, catalyst inlet, outflow condenser and vacuum system, add 2.43788g of PPDO and 4kg of L-lactide as shown in Table 1 below and perform 5 times of nitrogen rinse. The temperature was raised to 150°C to completely dissolve the L-lactide, and 120 ppmw of tin 2-ethylhexanoate catalyst was diluted with 500 ml of toluene as a catalyst, and the catalyst was added to the reaction vessel through the catalyst inlet. Next, the reaction was carried out at a temperature of 185° C. for 2 hours under a pressurized state of 1 kg of nitrogen, and 200 ppmw of phosphoric acid was added through the catalyst inlet and mixed for 15 minutes to passivate the remaining catalyst. Next, a vacuum reaction is performed up to 0.5 torr to remove unreacted L-lactide. And the molecular weight characteristics, Tg, Tm and %C _{of the} obtained resin were measured and shown in Table 1.

Preparation Example 11: Preparation of polylactic acid resin J

The preparation was carried out in the same manner as in Preparation Example 10 except that 6 g of 1-dodecyl alcohol was used instead of the polyol. And the molecular weight characteristics, Tg, Tm and %C _{of the} obtained resin were measured and shown in Table 1.

Preparation Example 12: Preparation of polylactic acid resin L

Add 11.0 of PBSA (polyester polyol) and HDI as shown in Table 1 below and perform nitrogen 5 times in an 8L reactor equipped with a nitrogen introduction tube, stirrer, catalyst inlet, outflow condenser, and vacuum system rinse. Dibutyltin dilaurate was used as a catalyst at 130 ppmw relative to the overall reactant content. Carry out urethane reaction at a reactor temperature of 190°C for 2 hours under a nitrogen gas flow, add 4 kg of L-lactide, completely dissolve L-lactide at 190°C under a nitrogen atmosphere, and use it as an addition polymerization catalyst. When the total reactant content was 120 ppmw of tin 2-ethylhexanoate and/or used as an esteramide exchange catalyst, 1,000 ppmw of dibutyltin dilaurate was diluted with 500 ml of toluene, and then charged into the reaction vessel. The reaction was carried out at a temperature of 190°C for 2 hours under a pressurized state of 1 kg of nitrogen, and 200 ppmw of phosphoric acid was added through the catalyst inlet and mixed for 15 minutes to passivate the remaining catalyst. Next, the vacuum reaction was performed up to 0.5 torr to remove unreacted L-lactide (about 5 parts by weight of the initial input amount). And the molecular weight characteristics, Tg, Tm and %C _{of the} obtained resin were measured and shown in Table 1.

Preparation of molded products of Examples 1 to 8 and Comparative Examples 1 to 8

After the polylactic acid resins prepared in the preparation examples 1 to 12 were dried under reduced pressure at 80° C. under 1 Torr vacuum for 6 hours, as shown in Table 2 or Table 3, a high-speed mixer was used ( super mixer) Mix polyamide resin and other materials, and process it in a double screw extruder with a hole diameter of 19mm (a single screw extruder, a roller crusher, a dough kneader or an internal mixer can be used for processing One of the instruments), melt-kneaded and extruded into strands under the extrusion temperature condition of 230-260°C. Will pass The water bath cooled chain is prepared into a pellet form using a pelletizer. It was dried at a temperature of 80°C with a dehumidifier or hot air dryer for more than 4 hours, and then injection molded to prepare a test piece. The evaluation results of the obtained molded products are shown in Table 2 or Table 3 together.

Test example

(1) NCO/OH: shows the isocyanate group/polyester-based polyol repeating unit (or (shared) of the “diisocyanate compound (for example, hexamethylene diisocyanate) used to form the polyolefin-based polyol repeating unit ) The reaction of the terminal hydroxyl group of the polymer)"

(2) OHV (KOHmg/g): Dissolve polyolefin polyol repeating unit (or (co)polymer) in dichloromethane and acetylate it, and hydrolyze it to produce acetic acid, and use 0.1N KOH methanol solution was titrated and measured. This corresponds to the number of hydroxyl groups present on the terminal of the repeating unit (or (co)polymer) of the polyolefin polyol.

(3) Mw and Mn (g/mol), and molecular weight distribution (Mw/Mn): polylactic acid resin was dissolved in chloroform at a concentration of 0.25% by weight, and gel permeation chromatography (Manufacturing Institute: Viscotek TDA 305, chromatography) Column: Shodex LF804*2ea) was measured, and polystyrene was used as a standard substance to calculate the weight average molecular weight (Mw) and number average molecular weight (Mn), respectively. The molecular weight distribution value (MWD) is calculated from Mw and Mn calculated in this way.

(4) Tg (glass transition temperature, °C): The sample was melted and rapidly cooled using a differential scanning calorimeter (manufacturing institute: TA instrument), and then measured at a temperature of 10 °C/min. The baseline near the endothermic curve and the mid value of each tangent line were taken as Tg.

(5) Tm (melting temperature, °C): The sample was melted and cooled rapidly by using a differential scanning calorimeter (manufacturing institute: TA instrument), and then the temperature was raised at 10 °C/min and measured. The maximum value of the melting endothermic peak of the crystal will be represented by Tm.

(6) Residual monomer (lactide) content (% by weight): 0.1 g of resin was dissolved in 4 ml of chloroform, 10 ml of hexane was added for filtration and quantified by GC analysis.

(7) Content of repeating unit (wt%) of polyolefin-based polyol: The content of repeating unit of polyolefin-based polyol included in the separately prepared polylactic acid resin was quantified using a 600 Mhz nuclear magnetic resonance (NMR) spectrometer.

(8) Wafer color-b value: A color difference meter (CR-410, Konica Minolta) was used to obtain the value of the resin wafer and the average value of the total 5 trials was taken.

(9) The content rate of organic carbon derived from biomass (%C _bio ): According to ASTM D6866, the biomass derived material concentration test based on radioactive carbon concentration (percent modern carbon; C14) measures the organic content derived from biomass Carbon content rate.

(10) Extrusion state: In a twin screw extruder with a hole die of 30 nm in diameter, the polylactic acid-polyamide alloy resin is extruded into chains at an extrusion temperature of 20 to 260°C After the shape, it was made high-phase in a cooling water bath at 20°C. At this time, the state of the melt viscosity (extrusion state) was evaluated by visually judging the melt viscosity and the homogeneity of the melt according to the following criteria.

◎: The compatibility between the two resins is good and the melt viscosity uniformity is also good, and the chain formation is good without breaking.

○: The compatibility between the two resins is slightly poor, and the melt viscosity uniformity is also slightly low, making it difficult to proceed, but it is possible to generate chains and break.

×: The compatibility between the two resins is extremely insufficient, and the melt viscosity uniformity is also poor, and die swelling occurs and the chain breaks and cannot be formed.

(11) MI (melt index): The test was carried out three times with a load of 2.06 kgf at a temperature of 220° C. according to ASTM D1238, and the average value thereof was expressed as the result value.

(12) Compatibility: The polylactic acid-polyamide alloy resin is extruded into a chain shape at an extrusion temperature of 230 to 260°C in a twin screw extruder with a hole die of 30 nm in diameter After that, it was made high-phase in a cooling water bath at 20°C to obtain a chain test piece, which was immersed and broken in liquid nitrogen, and the fracture surface was observed with a scanning electron microscope (SEM), and judged visually according to the following criteria .

⊚: The phase separation state between the two resins is good, and the particle diameter of the undispersed resin is 0.2 μm or less.

○: The phase separation state between the two resins is good, and the particle diameter of the undispersed resin is 1.0 μm or less.

×: The phase separation state between the two resins is poor, and the particle diameter of the undispersed resin is 1.0 μm or more.

(13) Appearance characteristics: The appearance was judged visually, and flow marks, weld lines, and gloss decline due to insufficient fluidity of the resin melt were judged.

◎: The melt viscosity is good without flow marks, the weld line is excellent, and the gloss is excellent.

◯: The melt viscosity is slightly higher without flow marks and weld lines, but the gloss is reduced.

×: The melt viscosity is very high, and flow marks, weld lines, and glossiness are low.

(14) Initial tensile strength (kgf/cm ² ): According to ASTM D638 at a temperature of 20° C., the test piece is aged for 24 hours in an atmosphere with a humidity of 65% RH, and then UTM (manufacturing company: Instron) (INSTRON)) After the universal testing machine has conducted 5 tests in total, the average value is used as the result value.

(15) Elongation (%): Under the same conditions as the initial tensile strength of (14), the elongation of the test piece until breakage was measured a total of 5 times, and the average value was used as the result value Said.

(16) Impact strength (kgf.cm/cm): A test piece for measurement was prepared according to ASTM D256, and the impact strength value was measured using an impact strength impactor (Izod impactor).

(17) Bending strength (kgf/cm ² ) and bending elastic modulus (kgf/cm ² ): A test piece for measurement was prepared according to ASTM D790, and measured using a UTM universal tester (manufacturing company: INSTRON), which was measured 5 times in total. The average value is used as the result value.

(18) Heat resistance (°C): A test piece for measurement was prepared according to ASTM D648, and the heat resistance was measured using a universal tester.

i) High temperature mold: use 110℃ high temperature mold during injection, and the cooling time is within 30 seconds

ii) Low temperature mold: use normal temperature mold during injection, cooling time is within 30 seconds

(19) Anti-bleed out: Observe the surface of the molded product and evaluate the degree of the low molecular weight plasticizer component overflowing onto the surface of the molded product using the A4 size film sample based on the tactile sensation according to the following criteria.

◎: No overflow occurred

○: Overflow occurred, but not serious

×: Serious overflow occurred

(20) Humidity and tensile strength maintenance rate (%): A film sample with a length of 150 mm and a width of 10 mm was placed at a temperature of 40° C. under a 90% RH humidity atmosphere and the change in tensile strength was measured after 30 days.

Referring to Table 2, Examples 1 to 5 and Examples 7 to 8 include the content of the flexible component (polyolefin-based polyol repeating unit) in the polylactic acid resin is 5 to 35% by weight, and the color-b value is low , And includes a molded product obtained from a polyamide alloy resin composition that has an appropriate content of antioxidants and has physical properties such as a weight average molecular weight of 100,000 to 400,000, a molecular weight distribution of 1.60 to 3.0, Tg20 to 60°C, and Tm145 to 178°C. In addition, Example 6 uses a polylactic acid resin (resin F) equivalent to the polylactic acid resin contained in the polylactic acid-polyamide alloy resin composition of the present invention and a polymer containing a general polylactic acid resin (resin K) The lactic acid-polyamide alloy resin composition is prepared.

The initial tensile strength of such injection molded products of Examples 1 to 8 are all 300 kgf/cm ² or more and the impact strength is 25 kgf. cm/cm or more, which not only has excellent mechanical and physical properties, but also has a high-temperature mold HDT of 85°C or more, thereby showing excellent heat resistance. In addition, at a temperature of 40°C and a humidity environment of 90% RH, the retention rate of the wet tensile strength after 80 days is more than 80%, which is very good, and no overflow phenomenon occurs. Moreover, the organic carbon content of the resin is 60% or more, so it can be called an environmentally friendly material.

In contrast, although various physical properties of the injection molded article of Comparative Example 1 prepared from the polylactic acid-polyamide alloy resin containing the polylactic acid resin A contained in the polylactic acid-polyamide synthetic resin composition of the present invention Good, but the content of organic carbon is below 25% and does not meet the world environmental plastic standards. Moreover, the extruded and kneaded resins of Comparative Examples 2 and 3 prepared using the polylactic acid-polyamide alloy resin composition including the commonly used polylactic acid resin K are insufficiently compatible with the polylactic acid resin and the polyamide resin, Moreover, the difference in melt viscosity between the two resins is too large, and the die swells during extrusion and kneading, and the extrusion state is poor, making it difficult to use as an injection molded product.

In addition, in the case of the injection molded products of Comparative Examples 4 and 5 prepared using the polylactic acid-polyamide alloy resin compositions of the polylactic acid resins I and J including the polyolefin urethane polyol in the soft segment, The compatibility is insufficient and the difference in melt viscosity between the two resins is too large. When the extrusion and kneading are discharged, die expansion or the like occurs and the extrusion state is poor, making it difficult to use as a molded product.

In addition, Comparative Examples 6 and 7 are poly(1,3-propanediol) having a polyolefin-based polyol repeating unit that does not include a softening component in the polylactic acid resin and a plasticizer, that is, a number average molecular weight of 2,400 An aliphatic polyester polyol made of 1,4-butanediol with a number average molecular weight of 11,000 and a condensate of succinic acid and adipic acid is simply mixed with polylactic acid resin K for injection molding. Such injection molded products of Comparative Examples 6 and 7 have poor compatibility, the degree of dispersion in the resin of the plasticizer component is incomplete, and the extrusion state and appearance characteristics of the melt during extrusion and kneading are poor, thereby After a period of time, it was found that the plasticizer component in the molded product overflowed.

In addition, the injection-molded article of Comparative Example 8 was prepared using a polylactic acid-polyamide alloy resin including a polylactic acid resin introduced with a polyester polyol repeating unit and having a wide molecular weight distribution. Since the flexible component polyamide was randomly introduced into the injection-molded product of the comparative example 8 with a small segment size, the molded product of the comparative example 8 exhibited excellent spill resistance. However, the polylactic acid resin It is introduced in a relatively small segment size, which shows poor heat resistance due to low Tm and the like, and makes various mechanical strengths poor due to compatibility problems. In addition, it was confirmed that due to the low compatibility of the polyester polyol and polylactic acid used to form the softening component, the extrusion kneaded product was not uniform, and the extrusion state of the molded product was poor and the mechanical and physical properties were reduced, And the moisture resistance is very poor.

In addition, the morphology of the particles prepared in Examples 1 to 3 and Comparative Example 4 was observed with a scanning electron microscope, and the results are shown in FIGS. 1 to 4. Referring to Figures 1 to 4, the white part is polylactic acid resin, and the black part is polyamide resin.

In the case of Figures 1 to 3, compared with Figure 4, it can be seen that the distinction between the polylactic acid resin in the white part and the polyamide resin in the black part is unclear regardless of the ratio of the polylactic acid resin and the polyamide resin Appear. This means that the compatibility between the two resins is increased without the use of a compatibilizing agent, and it indicates that the physical properties of bending elastic modulus and impact strength are evenly improved. However, the distinction between the polylactic acid resin and the polyamide resin in Figure 4 is obvious and the compatibility is poor, so that the mold expansion occurs when the two resins are melted and kneaded, and the cross section of the alloy resin can be seen An air layer (void) is generated. Since such a resin cannot obtain a uniform extrudate, it is difficult to prepare chains and pellets.

Based on the above results, it can be known that in the polylactic acid-polyamide alloy resin composition, the dispersibility of polylactic acid in polyamide or the dispersibility of polyamide resin in polylactic acid resin increases, which can improve the weakness The impact resistance, crystallization rate, heat resistance, etc. of the polylactic acid resin of the item can balance the overall physical properties of the resin composition.

Claims (14)

A polylactic acid-polyamide alloy resin composition, wherein the polylactic acid-polyamide alloy resin composition contains 30 to 90 parts by weight of polylactic acid resin and 10 to 70 parts by weight of polyamide resin, the polylactic acid resin includes The hard segment containing the polylactic acid repeating unit represented by the following Chemical Formula 1 and the polyolefin-based polyol constituent unit containing the following Chemical Formula 2 are connected to form a linear or branched type polymer using a urethane bond as a medium The soft segment of the repeating unit of the olefin polyol, and the organic carbon content rate (%C _bio ) derived from biomass defined by the following mathematical formula 1 is 60% or more:

Carbon atoms [Equation 1]% C _biological = (for the ¹⁴ C isotope ¹² C was isotopes weight ratio of carbon atoms in the polylactic acid resin) / (the biomass from the standard substance weight of the ¹⁴ C isotope ¹² C was isotope Ratio) × 100; in the above Chemical Formula 1 and Chemical Formula 2, n is an integer of 700 to 5,000, and m+1 is an integer of 5 to 200; wherein polylactic acid resin includes 65 to 95 based on 100 parts by weight of polylactic acid resin Parts by weight of the hard segment and 5 to 35 parts by weight of the soft segment, wherein the urethane bond is obtained by adding the hydroxyl group at the end of the polyolefin-based polyol constituent unit or the hydroxyl group at the end of the polyolefin-based polyol constituent unit A urethane bond formed by reacting a prepolymer having a lactide with a diisocyanate or an isocyanate compound having 3 or more isocyanate groups. The polylactic acid-polyamide alloy resin composition as described in item 1 of the patent application scope, wherein the polylactic acid resin and the polyamide resin are calculated as 100 parts by weight in total, further including an impact modification of 0.1 to 20 parts by weight Agent. The polylactic acid-polyamide alloy resin composition as described in item 1 of the patent application scope, wherein the content of ¹⁴ C isotope in carbon atoms of the polylactic acid resin is 7.2×10 ^-11 to 1.2×10 ^-10 % by weight. The polylactic acid-polyamide alloy resin composition as described in item 1 of the scope of patent application, wherein the organic carbon content rate (%C _bio ) defined by Mathematical Formula 1 in the soft segment is 70% or more. The polylactic acid-polyamide alloy resin composition as described in item 1 of the patent application range, wherein the polylactic acid resin has a number average molecular weight of 50,000 to 200,000 and a weight average molecular weight of 100,000 to 400,000. The polylactic acid-polyamide alloy resin composition as described in item 1 of the patent application range, wherein the polylactic acid resin has a glass transition temperature (Tg) of 20 to 55°C and a melting temperature (Tm) of 145 to 178°C. The polylactic acid-polyamide alloy resin composition as described in item 1 of the patent application scope, wherein the polylactic acid resin contains the terminal carboxyl group of the polylactic acid repeating unit contained in the hard segment and the polyolefin contained in the soft segment A block copolymer in which the terminal hydroxyl group of the polyol-like constituent unit is connected by an ester bond, or a block copolymer containing a block copolymer connected to a linear or branched chain using a urethane bond as a medium. The polylactic acid-polyamide alloy resin composition as described in item 7 of the patent application range, wherein the polylactic acid resin further includes a polylactic acid homopolymer that is not combined with a polyolefin-based polyol repeating unit. The polylactic acid-polyamide alloy resin composition as described in item 1 of the patent application range, wherein the polyolefin-based polyol repeating unit has a number average molecular weight of 1,000 to 100,000. The polylactic acid-polyamide alloy resin composition as described in item 1 of the patent application scope, wherein the reaction of the hydroxyl group at the end of the polyolefin-based polyol constituent unit with the isocyanate group of the diisocyanate or isocyanate compound having 3 or more isocyanate groups The molar ratio is 1:0.50 to 1:0.99. The polylactic acid-polyamide alloy resin composition as described in item 1 of the patent application scope, wherein the polyamide resin is polyhexamethyleneamide (nylon 6), polytetramethylenehexamethylenediamide diamide (nylon 46) 、Polyhexamethylene hexamethylene diamine (nylon 66), polynonadiamide hexamethylene diamine (nylon 69), polydecane hexamethylene diamine (nylon 610), polyhexamethylene amide/polyhexamethylene Hexanediamide diamide (nylon 6/nylon 66), polyhexamethylene dodecane diamide, polyhexamethylene dodecane amide (nylon 612), polyundecylamide (nylon 11), Polydodecylamide (nylon 12), polyhexamethylene isophthalamide (nylon 61), polyhexamethylene terephthalamide/polyhexamethylene isophthalamide copolymer (nylon 6T) /6I), polyhexamethylene hexamethylene diamine/polyhexamethylene terephthalamide copolymer (nylon 66/6T), polydodecane bis bis (4-aminocyclohexyl) methane (Nylon PACM12), poly-p-xylylene undecane diamine (nylon 11T), poly-hexahydro-p-xylylene undecane diamine (nylon 11T(H)), or a mixture or copolymer thereof. The polylactic acid-polyamide alloy resin composition as described in item 1 of the patent application range, wherein the polyamide resin has a viscosity coefficient (viscosity number; ISO307) of 120 to 220. The polylactic acid-polyamide alloy resin composition as described in item 1 of the patent application scope, The polylactic acid-polyamide alloy resin composition shows a color-b value of less than 15. The polylactic acid-polyamide alloy resin composition as described in item 1 of the scope of the patent application, wherein, based on the total polylactic acid resin, less than 1% by weight of the monomer remains.

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