JP2005246718A - Biodegradable resin pellet and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a biodegradable pellet for efficiently adding an additive, which is reduced in coloration and can enhance abrasion-resistant characteristics in a case formed into a fiber or a film, to a final product, and its manufacturing method. <P>SOLUTION: The biodegradable resin pellet comprises 80 wt.% or above of a biodegradable polyester resin and satisfies characteristics (A) that a b-value is -3 to 13, (B) that a particle size (an average value calculated from the weight of 100 pellets) is 2-50 (mg/piece) and (C) that the content of a fatty acid amide and/or a fatty acid ester is 0.1-10 wt.%. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a biodegradable resin pellet for efficiently adding an additive capable of improving abrasion resistance when it is made into a fiber or film into a final product, and a method for producing the same.

  Recently, there has been a strong demand for the development of polymer materials that can be decomposed in the natural environment in response to environmental problems on a global scale, and research and development of various polymers such as aliphatic polyesters and attempts to put them into practical use are active. It has become. Attention has been focused on polymers that are degraded by microorganisms, that is, biodegradable polymers.

  On the other hand, most of the conventional polymers are made from petroleum resources, but they have been stored in the ground since the geological era due to the fact that the petroleum resources will be depleted in the future and that they are consumed in large quantities. There is concern that carbon dioxide will be released into the atmosphere and global warming will become more serious. However, if a polymer can be synthesized using plant resources that grow by taking in carbon dioxide from the atmosphere, it is possible not only to suppress global warming through carbon dioxide circulation, but also to solve the problem of resource depletion at the same time. . For this reason, attention has been focused on polymers using plant resources as raw materials, that is, polymers using biomass.

  From the above two points, biodegradable polymers using biomass attract great attention and are expected to replace conventional polymers made from petroleum resources. However, biodegradable polymers using biomass generally have problems such as low mechanical properties and heat resistance and high cost. As the biodegradable polymer using biomass that can solve these problems, polylactic acid is particularly attracting attention among aliphatic polyesters. Polylactic acid is a polymer made from lactic acid obtained by fermenting starch extracted from plants. Among biodegradable polymers using biomass, it has the best balance of mechanical properties, heat resistance, and cost. And the development of fibers using this is accelerating. However, polylactic acid when viewed as a fiber or a film has a problem in abrasion resistance, and when used for a long time, there are problems such as scraping and whitening due to friction, and in the case of a fiber, dye transfer.

As means for solving this, for example, a method of coating fibers with a polymer having high wear resistance, a method of reducing surface friction by adding a lubricant, etc. are proposed. In particular, for the latter, fatty acid bisamide and / or Alternatively, a method of adding a lubricant such as an alkyl-substituted fatty acid monoamide or a fatty acid ester has been proposed (see, for example, Patent Document 1 and Patent Document 2). However, these methods do not improve the wear resistance of the final product, but are proposed for the purpose of controlling the crystallization of the molded product and improving the releasability from the mold.
JP 09-278991 A Japanese Patent Laid-Open No. 08-183898

  An object of the present invention is to solve the above-mentioned problems of the prior art, in order to efficiently add an additive capable of improving the wear resistance when used as a fiber or a film in a final product with little coloring. It is providing the biodegradable resin pellet and its manufacturing method.

In order to solve the above problems, the present invention adopts the following configuration. That is,
(1) Biodegradable resin pellets characterized in that 80% by weight or more is a biodegradable polyester resin and satisfies the following characteristics (A) to (C).

(A) b value: -3 to 13
(B) Particle size: 2-50 (mg / piece)
(C) Fatty acid amide and / or fatty acid ester content: 0.1 to 10 (% by weight)
However, the particle size is an average value calculated from the weight per 100 pellets. (2) The biodegradability according to (1), wherein the fatty acid amide is a fatty acid bisamide and / or an alkyl-substituted fatty acid monoamide. Resin pellets.

  (3) The biodegradable resin pellet according to (1) or (2), wherein the biodegradable polyester resin is polylactic acid.

  (4) When the fatty acid amide and / or fatty acid ester is added to the biodegradable polyester and kneaded, the total amount of the additive is 0.1 to 10% by weight, and the following (1) to (2) The manufacturing method of the biodegradable resin pellet characterized by satisfy | filling Formula.

T × (Tsv−Tm) ≦ 15 (1)
Tsv−Tm ≦ 30 (2)
T: kneader residence time (min)
Tsv: Maximum temperature set in the kneader (° C)
Tm: melting point of biodegradable polyester (° C.)
(5) When the pellet made of biodegradable polyester and the fatty acid amide and / or fatty acid ester are added and mixed into the melt kneader, the organic low-functionality having a film forming ability on the surface of the biodegradable polyester pellet in advance. The method for producing biodegradable resin pellets according to (4), wherein a molecular weight compound is adhered, and then fatty acid amide and / or fatty acid ester is added and mixed.

  (6) The biodegradability as described in (5) above, wherein the organic low molecular weight compound having film-forming ability is an ether having a polyoxyethylene chain, and its weight average molecular weight is 400 to 4000. Production method of resin pellets.

  According to the present invention, it is possible to obtain a final product such as a fiber or a film having both color tone and abrasion resistance.

  The biodegradable polyester as used in the present invention refers to a polymer having an ester bond in a molecular chain and having thermoplasticity, such as polylactic acid, polyglycolic acid, polycaprolactone, polybutylene succinate, polyhydroxybutyrate and the like. Is mentioned. In particular, it is preferable that the biodegradable polyester is polylactic acid because it has a good balance between mechanical properties and cost and can contribute to the formation of a recycling society as a non-petroleum material. When polylactic acid is used for the biodegradable polyester, it is preferable that the optical purity of the L-form or D-form is 90% or higher because the melting point is high. In addition, polylactic acid contains additives such as polymers and particles, flame retardants, antistatic agents, matting agents, etc., as long as it does not impair the properties of polylactic acid. May be. However, from the viewpoint of biomass utilization and biodegradability, it is important that the lactic acid monomer is 50% by weight or more as a polymer. The lactic acid monomer is preferably 75% by weight or more, more preferably 96% by weight or more. Moreover, when the weight average molecular weight of polylactic acid is 50,000 to 500,000, it is preferable that the balance between mechanical properties and spinning properties is good. Further, in the case of a biodegradable polyester other than polylactic acid, it may contain additives such as other polymers and particles, flame retardants, antistatic agents, matting agents and the like as long as the properties are not impaired. In addition, it may be copolymerized with other monomers and oligomers.

  In addition, residual monomers such as lactide are present in polylactic acid, but these low molecular weight residues promote hydrolysis, reduce durability, and thus act as a coloring material for the polymer. Therefore, the amount of residual lactide is preferably 1% by weight or less, more preferably 0.5% by weight or less, and still more preferably 0.2% by weight or less. On the other hand, the amount of residual lactide can uniformly disperse the additive in the biodegradable polyester by interaction with the low molecular weight additive. Therefore, it is preferable to contain 0.005 weight% or more. Furthermore, when the amount of lactide contained in the polylactic acid resin pellets after the addition of the additive is 1% by weight or less, the color tone of the final product can be kept close to white, and the final product can be added with water. Since it becomes possible to suppress decomposition | disassembly, durability can also be improved. From this, the amount of residual lactide in the polylactic acid resin pellet is preferably 0.5% by weight or less, and most preferably 0.2% by weight or less.

  Moreover, when the molecular weight of the polylactic acid polymer is 50,000 to 500,000 in terms of weight average molecular weight, a good balance between mechanical properties and yarn-forming properties is preferable when it is fiberized.

  In addition, dicarboxylic acids and diols remain as low molecular weight substances in biodegradable polyesters other than polylactic acid, and these also exhibit the same effect as lactide in polylactic acid. It is preferable that it is not more than 05 wt%.

  In the present invention, the b value of the biodegradable resin pellet is −3 to 13.0, which is important for setting the color tone of the final product to a practical level. The b value is a value used for evaluating the whiteness of the polymer because generally the yellow value increases as the value increases. Although the application range of the b value varies depending on the use, it is particularly severe for clothing that requires whiteness of the fabric, and the b value is preferably -2.5 to 11.0, more preferably -2 to 10.0. Preferably, it is -2 to 6.0.

  It is important that the particle size (weight per pellet) of the biodegradable resin pellet of the present invention is 2 to 50 mg / piece on an average per 100 pellets. When the particle size is within this range, it is possible to suppress the demixing phenomenon, that is, the phenomenon of separation of biodegradable resin pellets from other resin pellets in blends with other resins, and so on. It becomes possible to add an additive to this. Furthermore, if the particle size is 2 mg / piece or more, surging in the melt extruder during molding can be suppressed, and stable discharge becomes possible. Further, when the particle size is 50 mg / piece or less, the biting into the melt extruder is good, and it is possible to efficiently perform the pellet feeding. Accordingly, the particle size is more preferably 4 to 47 mg / piece, and most preferably 5 to 45 mg / piece. In particular, it is preferable to set the particle size within the above-mentioned range because, in a biodegradable resin with low wear resistance, for example, generation of powder due to scraping during transportation can be suppressed.

  It is preferable that the powder polymer adhering to the biodegradable resin pellet of the present invention is 100 mg / (g pellet) or less. Since biodegradable resins generally have low wear resistance, powder is often generated due to scraping or cracking during handling. As used herein, the powder polymer means one that passes through a 30 mesh filter. In addition to clogging of blowers and exhaust fans of pneumatic transporters (newmer lines) and clogging of the filter, powdered polymers cause poor operation and poor operability, and poor discharge due to screw pressure fluctuations in the melt extruder. However, if it is less than 100 mg / (g pellet), it is preferable because it is possible to avoid the above problems. The amount of the powder polymer is more preferably 50 mg / (g pellet) or less, and most preferably 30 mg / (g pellet) or less.

  In the present invention, a fatty acid amide and / or a fatty acid ester is contained as a lubricant in an amount of 0.1 to 10 wt% based on the entire fiber.

  A molded body made of biodegradable polyester has extremely poor wear resistance compared to a molded body made of a general-purpose resin such as polyethylene terephthalate or polyamide. This is considered to be because the molecular chain interaction of the biodegradable polyester is small and the molecular chains are easily peeled off. This tendency becomes more prominent as the temperature becomes higher. For this reason, for example, when the molded article is run at a high speed in the yarn forming or film forming process, the sliding portion may easily be scraped. Even after becoming a product such as clothing or film laminate, when repeated use or a strong frictional force is applied, the surface is shaved due to wear, and only a product that cannot withstand practicality can be obtained. For such problems, a specific lubricant is added to form a lubricant film on the surface of the molded body, so that the surface friction coefficient is lowered, so that it is possible to prevent stress from being applied until breakage is applied. .

  Examples of the lubricant preferably used in the pellet made of the biodegradable polyester used in the present invention include fatty acid amides and / or fatty acid esters.

  Examples of the fatty acid amide used in the present invention include lauric acid amide, palmitic acid amide, stearic acid amide, erucic acid amide, behenic acid amide, methylol stearic acid amide, methylol behenic acid amide, dimethylol oil amide, and dimethyl lauric acid. A compound having two amide bonds in one molecule such as amide, dimethyl stearamide, saturated fatty acid bisamide, unsaturated fatty acid bisamide, aromatic bisamide, etc., for example, methylene biscaprylic amide, methylene biscapric amide, Methylene bis lauric acid amide, methylene bis myristic acid amide, methylene bis palmitic acid amide, methylene bis stearic acid amide, methylene bis isostearic acid amide, methylene bis behenic acid amide, methylene bis olei Acid amide, methylene biserucic acid amide, ethylene biscaprylic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bismyristic acid amide, ethylene bispalmitic acid amide, ethylene bisstearic acid amide, ethylene bisisostearic acid amide , Ethylene bis behenic acid amide, ethylene bis oleic acid amide, ethylene bis erucic acid amide, butylene bis stearic acid amide, butylene bis behenic acid amide, butylene bis oleic acid amide, butylene bis erucic acid amide, hexamethylene bis Stearic acid amide, hexamethylene bis behenic acid amide, hexamethylene bis oleic acid amide, hexamethylene bis erucic acid amide, m-xylylene bis stearic acid amide, m-xylylene S-12-hydroxystearic acid amide, p-xylylene bis-stearic acid amide, p-phenylene bis-stearic acid amide, p-phenylene bis-stearic acid amide, N, N′-distearyl adipic acid amide, N, N′- Distearyl sebacic acid amide, N, N′-dioleyl adipic acid amide, N, N′-dioleyl sebacic acid amide, N, N′-distearyl isophthalic acid amide, N, N′-distearyl terephthalic acid amide, Examples include methylene bishydroxystearic acid amide, ethylene bishydroxystearic acid amide, butylene bishydroxystearic acid amide, and hexamethylene bishydroxystearic acid amide.

  The alkyl-substituted fatty acid monoamide referred to in the present invention refers to a compound having a structure in which an amide hydrogen such as a saturated fatty acid monoamide or an unsaturated fatty acid monoamide is replaced with an alkyl group, such as N-lauryl lauric acid amide, N- Palmityl palmitic acid amide, N-stearyl stearic acid amide, N-behenyl behenic acid amide, N-oleyl oleic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, N-oleyl And palmitic acid amide. The alkyl group may have a substituent such as a hydroxyl group introduced into its structure. For example, methylol stearamide, methylol behenic acid amide, N-stearyl-12-hydroxystearic acid amide, N- Oleyl 12 hydroxystearic acid amide and the like are also included in the alkyl-substituted fatty acid monoamide of the present invention.

  Furthermore, the fatty acid ester used in the present invention includes, for example, lauric acid cetyl ester, lauric acid phenacyl ester, myristic acid cetyl ester, myristic acid phenacyl ester, palmitic acid isopropylidene ester, palmitic acid dodecyl ester, palmitic acid tetra Aliphatic monocarboxylic esters such as dodecyl ester, palmitic pentadecyl ester, palmitic octadecyl ester, palmitic acid cetyl ester, palmitic acid phenyl ester, palmitic acid phenacyl ester, stearic acid cetyl ester, behenic acid ethyl ester; monolaurin Monoesters of ethylene glycol such as acid glycol, glycol monopalmitate, glycol monostearate, glycol dilaurate, diester Diesters of glycols such as glycol lumitate and glycol distearate; monoesters of glycerin such as monolaurate glycerin ester, monomyristylate glycerin ester, monopalmitate glycerin ester, monostearate glycerin ester; dilaurate glycerin ester, dimistilin Glycerin diesters such as acid glycerin ester, dipalmitic acid glycerin ester, distearic acid glycerin ester; trilauric acid glycerin ester, trimistylic acid glycerin ester, tripalmitic acid glycerin ester, tristearic acid glycerin ester, palmitodiolein, palmitodistearin And glycerol triesters such as oleodistearin.

  Among these compounds, it is preferable to use fatty acid bisamides and alkyl-substituted fatty acid monoamides. Fatty acid bisamides and alkyl-substituted fatty acid monoamides are less reactive with amides than ordinary fatty acid monoamides, so that they do not easily react with biodegradable polyesters, especially polylactic acid, during melt molding, and have a higher molecular weight. Because of its high heat resistance, it has high heat resistance, and since it does not easily sublime by melt molding, it exhibits excellent slipperiness without impairing the function as a lubricant. In particular, fatty acid bisamides can be used more preferably because the reactivity of amides is even lower, and ethylene bisstearic acid amide is more preferred.

  In the present invention, two or more fatty acid amides and fatty acid esters may be used, or fatty acid amides and fatty acid esters may be used in combination.

  It is important that the content of the fatty acid amide and / or the fatty acid ester is 0.1 wt% or more based on the pellet weight in order to exhibit the above characteristics. Moreover, when there is too much content, the moldability of a pellet will worsen, the mechanical characteristic of the pellet obtained is inferior, and also what only gets yellowish is obtained. Therefore, the content of the fatty acid amide and / or fatty acid ester is preferably 0.3 to 9 wt%, more preferably 0.5 to 8 wt%, and most preferably 1 to 7 wt%.

  By using these lubricants, it becomes possible to mix well with the biodegradable polyester, stabilize the quality of the resulting biodegradable resin pellets, and further, when used as a final product, the physical properties of the biodegradable polyester The characteristics such as wear resistance can be improved without impairing the resistance. In addition, it is possible to improve the wear resistance of the biodegradable resin pellet itself, for example, it is possible to suppress scraping during pneumatic transportation, and contribute to process stabilization.

  The shape of the pellet is not particularly limited, such as a saddle shape, a spherical shape, or a cylindrical shape. However, when used by mixing with other resins, the shape of the pellet is preferably the same as that of the resin pellet. However, when melt-kneading is performed, a saddle type or a cylindrical type is preferable from the viewpoint of ease of production and handling.

  In addition, the pellet of the present invention is a two-layered pellet composed of an inside in which an additive is added at a high concentration and an outside made of a biodegradable polyester resin not containing the additive. Can be manufactured. Furthermore, since it can suppress that an additive bleeds from the obtained pellet, handling properties, such as conveyance and storage, improve, and it is preferable. In the two-layer structure, the external biodegradable polyester resin may completely cover the resin in which the internal additive is highly added, or the internal resin may be partially exposed. From the viewpoint of manufacturing cost, a form in which the inner resin is concentrically covered when the outer resin is in a gut state is also preferably used.

  When the biodegradable resin pellet obtained in the present invention is in the range of the solution specific viscosity derived by the following formula (3), there is little change in the melt viscosity given to the final product, and stable spinning and film molding are possible. Therefore, it is preferable.

η _af. ÷ η _be. ≧ 0.6 (3)
η _{be .} : Solution specific viscosity of the biodegradable polyester before kneading η _af .: Solution specific viscosity of the biodegradable polyester after kneading The ratio of the solution specific viscosity calculated by the equation (3) is 0.6 or more. In addition, when the final product is produced, even if it is mixed with a resin that does not contain an additive, the effect on the melt viscosity of the resin is small, so that it can be molded without greatly changing the production conditions. From this, the right side of the formula (3) is more preferably 0.7 or more, and most preferably 0.8 or more.

  When producing the biodegradable resin pellet of the present invention, the residence time and set temperature in the kneader are preferably in the range of the following formulas (1) to (2).

T × (Tsv−Tm) ≦ 15 (1)
Tsv−Tm ≦ 30 (2)
T: Kneader residence time (min)
Tsv: Maximum temperature set in the kneader (° C)
Tm: melting point of biodegradable polyester (° C.)
In particular, by setting the kneader residence time and the kneader set maximum temperature in the formulas (1) and (2), thermal decomposition due to shear heat generation during kneading and polymer degradation due to heat conduction on the cylinder inner surface are sufficiently suppressed. Thus, excellent quality biodegradable resin pellets can be obtained. Further, when the kneader residence time in the formula (1) is between 0.2 and 1.5 minutes, the biodegradable polyester is prevented from being thermally deteriorated, thereby preventing coloring, and further sufficient additives are added. This is preferable because it can be dispersed. From the viewpoint of preventing thermal deterioration, the kneader residence time is more preferably 0.2 to 1.2 minutes, and most preferably 0.2 to 1 minute.

  In addition, by setting the temperature higher than the melting point of the biodegradable polyester, the biodegradable polyester is sufficiently melted inside the kneader and the additive can be finely dispersed in the polymer. The quality of the conductive resin pellet can be improved. Further, when the calculated value of the formula (2) is 30 or less, the coloring of the polymer is prevented, and the bleeding of the additive is suppressed, so that stable kneading and pelletizing are possible. In order to obtain a viscosity of the molten resin that can be kneaded, it is preferable from the viewpoint of process stabilization that the kneader set maximum temperature is higher than Tm. From this, the kneader set maximum temperature is preferably in the range of Tm to Tm + 30 ° C, more preferably Tm to Tm + 25 ° C, and most preferably Tm to Tm + 20 ° C.

  As a result of intensive studies, the inventors of the present invention have excellent color tone by adding kneading conditions satisfying the above formulas (1) and (2), and even if they are contained in a high concentration, they are added to the resin. It was found that excellent biodegradable resin pellets in which the product was sufficiently dispersed could be obtained.

  The kneading machine of the present invention is not particularly limited, but if it is a twin screw type extruder having a specific vent port, sufficient performance for kneading effect and conveying effect can be obtained, and generated by the vent port. Since the deteriorated low molecular weight product can be removed, coloring of the final product can be suppressed, which is preferable.

  When the ratio (L / D) of the length (L) of the cylinder part to the cylinder diameter (D) is in the range of 20 to 60, the kneader of the present invention can sufficiently knead the additive and polymer inside the cylinder. This is preferable because it can be applied to the screw shaft and a high torque load can be applied to the screw shaft. If L / D is 20 or more, the biodegradable polyester and additive can be sufficiently kneaded. If L / D is 60 or less, thermal degradation of the biodegradable polyester is suppressed, and the color tone changes. Can be brought to a practical level. From this, L / D is more preferably in the range of 25 to 57, and most preferably in the range of 30 to 55.

  Moreover, it is preferable to design the element of the kneader screw so that the resin temperature inside the kneader becomes Tm + 40 ° C. or less. When the temperature of the internal resin is high, that is, when the frictional heat generation of the polymer due to shearing is large, in addition to deterioration due to temperature, deterioration due to shearing force is also added, so the molecular weight of the resulting biodegradable resin pellets is reduced. At the same time, the color tone deteriorates and the desired pellets cannot be obtained. For this reason, the resin temperature is more preferably Tm + 35 ° C. or less, and most preferably Tm + 30 ° C. or less.

  In the present invention, in order to obtain a desired kneading ability while lowering the resin temperature inside the kneader, that is, reducing the shearing force applied to the polymer, the shape of the screw conveying element is preferably a double thread. Even in a single screw screw, it is possible to reduce the shearing force, but it is difficult to sufficiently disperse the additive in the resin because the polymer carrying capacity is too large and the shearing force is insufficient. . In addition, the kneading effect is sufficient with the triple thread screw, but the shear heat generation is large, the thermal deterioration of the obtained resin proceeds, and it becomes difficult to bring the color tone to a practical level.

  In the screw of the present invention, the meshing rate of the double screw is a value calculated by the following formula (4), and is preferably 1.4 or more and 2.4 or less. By setting the meshing ratio to 1.4 or more, sufficient shear can be imparted to the molten polymer, and the additive can be sufficiently dispersed in the polymer. Moreover, since the retention time of the polymer inside the cylinder can be shortened by setting the meshing rate to 2.4 or less, the color tone of the obtained biodegradable resin pellet can be maintained at a practical level. . However, the meshing rate does not have to be constant in the longitudinal direction of the screw, and the meshing rate calculated by the equation (4) for each screw element may be in the above range.

Engagement rate = (screw diameter) / (screw root diameter) (4)
Here, the crest diameter and the trough diameter of the screw are the lengths of the portions shown in FIG.

  The concentration of the additive in the present invention is preferably in the range of 0.1 to 10 wt% with respect to the biodegradable polyester. In particular, by setting the addition concentration to 0.1 wt% or more, the purpose of the biodegradable resin pellet for adding the additive to the final product at a low cost can be sufficiently achieved. Further, when the additive concentration is 10 wt% or less, it is possible to prevent poor dispersion of the additive with respect to the biodegradable resin and stably spread the strand. From this, the addition concentration is preferably 0.3 to 9 wt%, and most preferably 0.5 to 7.0 wt%.

  Moreover, the method of adding the additive of this invention to biodegradable polyester can be performed using a conventionally well-known method. For example, a method of directly mixing an additive with a biodegradable polyester pellet, a method of supplying from the side of a cylinder using a side feeder, and adding a different amount from the same inlet as the biodegradable polyester pellet The method etc. are mentioned. Among these, the method of directly mixing the additives is preferable because it can be carried out regardless of the incidental equipment of the extruder. At this time, an organic low molecular weight compound with the ability to form a film to improve the miscibility (adhesiveness) between the additive and the biodegradable polyester pellets, to prevent the additive from falling off during transportation and storage, and to eliminate concentration spots A method is conceivable in which is added in advance to biodegradable polyester pellets and adhered, and then the additive is adhered. The organic low molecular weight product must be one that does not adversely affect the physical properties of the biodegradable polyester in the kneading process and final product manufacturing process. From the aspect, it was found that polyoxyethylene alkyl ether is preferably used. However, since the additive may contaminate the raw material hopper in this method, it is more preferable to supply from the side of the cylinder using a side feeder if possible.

  As described above, polyoxyethylene alkyl ether is suitably used for the organic low molecular weight compound having film forming ability. The compound can form a film on the surface of the biodegradable polyester as a surfactant, and can efficiently attach the additive to the surface of the biodegradable polyester pellet. Among the polyoxyethylene alkyl ethers, it is particularly preferable that the ethylene chain repeating unit is 4 and the alkyl part is an oleyl group or a cetyl group in terms of heat resistance and film forming ability. Moreover, since the organic low molecular weight compound is a component derived from a natural product, even if it remains in the final product, it is preferable because of high safety. Moreover, since it is a component derived from a natural product, even when a residue is present in the final product using polylactic acid, its biodegradability is not impaired, which is preferable.

  The weight average molecular weight of the organic low molecular weight compound having film forming ability is preferably 400 to 4000, since a stable film can be formed without bleeding during kneading or molding. In particular, as a result of intensive studies by the inventors of the present application, it was found that a courageous low molecular weight compound having a molecular weight in the above range is excellent in film forming ability for polylactic acid. Furthermore, the weight average molecular weight of the organic low molecular weight compound is preferably in the range of 500 to 3000, and most preferably in the range of 600 to 2500.

  Hereinafter, the present invention will be specifically described with reference to Examples. In addition, the following method was used for the measuring method of the value described in the Example.

A. Weight average molecular weight of biodegradable resin The sample chloroform solution was mixed with THF (tetrahydrofuran) to obtain a measurement solution. This was measured by GPC (gel permeation chromatography), and the weight average molecular weight was determined in terms of polystyrene.

B. Color tone About the biodegradable resin pellet obtained by the Example and final product, the color tone was measured with SM color computer (model SM-3) by Suga Test Instruments Co., Ltd., and b value was used as an evaluation item. Moreover, about the undyed textiles obtained in the Example, b value was set to 5.0 or less as the pass.

C. Melting point of biodegradable resin Using a differential scanning calorimeter DSC-7 manufactured by PerkinElmer, Inc., the melting point is the temperature that gives the extreme value of the melting endothermic curve obtained by measuring 20 mg of sample at a heating rate of 20 ° C./min. (° C).

D. Particle size 100 biodegradable resin pellets obtained were sampled, the weight thereof was measured, and the particle size in 100 pellets was calculated.

E. Powder polymer amount 100 g of the obtained biodegradable resin pellets were weighed and shaken with a 30 mesh filter for 10 minutes, and then the weight of the passed powder polymer was measured to determine the amount of powder per gram of pellets.

F. Solution specific viscosity (η)
0.10 g of biodegradable resin pellets are precisely weighed, dissolved in 10 ml of orthochlorophenol over 30 minutes in an environment of 100 ° C., and the flow time T 0 of the solvent alone and the flow time T 1 of the sample solution are determined using an Ostwald viscometer. The solution specific viscosity (η) was determined from T1 / T0.

G. Kneader residence time The volume of the resin residence portion in the kneader was calculated, and the residence time was calculated from the polymer discharge capacity.

H. Abrasion resistance evaluation The fabrics obtained in Examples and Comparative Examples are treated according to JIS L-1018 (1999) Taber method, the surface wear state is visually observed, and those that are sufficiently applicable to production are: A three-stage evaluation was performed with a mark applicable to production as ◯ and a mark not applicable as production as x, and a score of ◯ or higher was accepted.

I. Lactide amount 1 ± 0.001 g of the sample is precisely weighed, and 20 ml of dichloromethane is added and ultrasonically dissolved. Thereafter, 5 ml of acetone is added, the volume is adjusted to 50 ml using cyclohexane, and further ultrasonically dissolved. Thereafter, 20 μl of the supernatant was injected into the GC analyzer, and the amount of lactide was determined from the calibration curve determined in advance from the obtained chart.

Production Example 1 (Production of polylactic acid)
Polymerization of lactide prepared from L-lactic acid having an optical purity of 99.5% in the presence of bis (2-ethylhexanoate) tin catalyst (lactide to catalyst molar ratio = 10000: 1) at 180 ° C. for 140 minutes in a nitrogen atmosphere. Polylactic acid P1 was obtained. The resulting polylactic acid had a weight average molecular weight of 135,000. Further, the obtained polymer was pelletized by a conventionally known method. At this time, the particle size of the obtained pellet was 35 mg / piece, and the amount of powder was 80 mg / piece. Moreover, it was 2.8 when the solution specific viscosity of the pellet was measured. The resulting polylactic acid P1 had a melting point (Tm) of 168 ° C. Furthermore, when the residual lactide amount was measured, it was 0.13% by weight.

Example 1
1900 g / min of polylactic acid P1 having a weight average molecular weight of 135,000 and a b value of 2.2, previously dried, and ethylene bis-stearic acid amide (EBA) as additive (Alfro H-50S manufactured by NOF Corporation) Is measured with a separate feeder at 100 g / min, after kneading using a twin-screw kneading extruder with a screw engagement rate of 2.0 with a kneader setting maximum temperature Tsv of 180 ° C. and a residence time T of 0.45 minutes. A strand was sprinkled into water and passed through a cutter to obtain biodegradable resin pellets. At this time, the calculated value of T × (Tsv−Tm) was 5.4. The calculated value of Tsv-Tm was 12.
The obtained biodegradable resin pellet had a b value of 5.0 and exhibited an excellent color tone. Moreover, when the particle size of the biodegradable resin pellet was measured, it was 35 mg / piece, which was excellent in handleability. Further, the solution specific viscosity of the biodegradable resin pellet was 2.76, and an excellent solution specific viscosity retention rate was exhibited. Moreover, the amount of powder was 20 mg / (g pellet), and the handleability was excellent. Furthermore, when the residual lactide amount was measured, it was 0.15 weight%.
Furthermore, chip blending was performed using the biodegradable resin pellets and the polylactic acid P1 obtained in [Production Example 1] so that the concentration of the additive was 1% by weight. The resin after the chip blending was stirred and dried in a vacuum at 80 ° C. to make it completely dry, and then charged into the spinning hopper 1 shown in FIG. Thereafter, the extruder 2 is wound at a spinning speed of 4500 m / min from a die 6 having a die diameter of 0.25 mmφ at a melting temperature of 210 ° C. and a spinning temperature of 220 ° C. at a spinning speed of 4500 m / min, 133 dtex-24 filament. Highly oriented undrawn yarn was obtained. At this time, the highly oriented undrawn yarn was given 0.6% of a pure water-based emulsion oil containing 40% by weight of a fatty acid ester. The highly oriented undrawn yarn was false twisted at a processing speed of 400 m / min, a processing magnification of 1.4 times, a belt angle of 102.5 ° and a heater temperature of 130 ° C. with a high speed false twisting machine MACH33H manufactured by Murata Manufacturing Co., Ltd. A 24 filament false twisted yarn was obtained. This false twisted yarn was twisted at 200 T / m to obtain a 2/1 twill fabric. When the color tone of the fabric was measured, the b value was 3.8, which was very excellent. In addition, when the wear resistance was evaluated, the wear resistance was excellent.

Example 2
Biodegradable resin pellets were obtained in the same manner as in Example 1 except that polylactic acid P1 was supplied at 1850 g / min and EBA was supplied at 150 g / min.
The obtained biodegradable resin pellets had a b value of 10.3 and showed a good color tone. Moreover, when the particle size of the biodegradable resin pellet was measured, it was 35 mg / piece, which was excellent in handleability. Further, the solution specific viscosity of the biodegradable resin pellet was 2.75, and an excellent solution specific viscosity retention rate was exhibited. Moreover, the amount of powder was 25 mg / (g pellet), and the handleability was also excellent. Furthermore, when the residual lactide amount was measured, it was 0.15 weight%.
Further, a 2/1 twill woven fabric was prepared in the same manner as in Example 1. Although slight yarn breakage was observed at the spinning stage, the product could be obtained without problems. When the color tone of the woven fabric was measured, the b value was 4.5, which was excellent. In addition, when the wear resistance was evaluated, the wear resistance was excellent.

Example 3
Biodegradable resin pellets were obtained in the same manner as in Example 1 except that polylactic acid P1 was supplied at 1950 g / min and EBA was supplied at 50 g / min.
The obtained biodegradable resin pellet had a b value of 4.5 and exhibited an excellent color tone. Moreover, when the particle size of the biodegradable resin pellet was measured, it was 35 mg / piece, which was excellent in handleability. Further, the solution specific viscosity of the biodegradable resin pellet was 2.77, and an excellent solution specific viscosity retention rate was exhibited. Further, the amount of powder was 28 mg / (g pellet), and the handleability was excellent. Furthermore, when the residual lactide amount was measured, it was 0.15 weight%.
Further, a 2/1 twill woven fabric was prepared in the same manner as in Example 1. There was no yarn breakage at the spinning stage, and the product could be obtained without problems. When the color tone of the woven fabric was measured, the b value was 3.6, which was excellent. In addition, when the wear resistance was evaluated, the wear resistance was excellent.

Comparative Example 1
Biodegradable resin pellets were obtained in the same manner as in Example 1 except that polylactic acid P1 was supplied at 2000 g / min and kneading was performed without adding EBA.
The obtained biodegradable resin pellets had a b value of 4.1 and exhibited an excellent color tone. Moreover, when the particle size of the biodegradable resin pellet was measured, it was 35 mg / piece, which was excellent in handleability. Further, the solution specific viscosity of the biodegradable resin pellet was 2.77, and an excellent solution specific viscosity retention rate was exhibited. Further, the amount of powder was 55 mg / (g pellet), and sufficient handleability was maintained. Furthermore, when the residual lactide amount was measured, it was 0.15 weight%.
Further, a 2/1 twill woven fabric was prepared in the same manner as in Example 1 except that the concentration of the additive was changed to 0% by weight. There was no yarn breakage at the spinning stage, and the product could be obtained without problems. When the color tone of the woven fabric was measured, the b value was 3.4, which was excellent. However, since the EBA was not added, the wear resistance was evaluated, and a hole was formed in the fabric sample.

Comparative Example 2
Biodegradable resin pellets were obtained in the same manner as in Example 1 except that polylactic acid P1 was supplied at 1700 g / min and EBA was supplied at 300 g / min.
The obtained biodegradable resin pellet had a b value of 14.5 and was highly colored. However, when the particle size and the amount of powder of the biodegradable resin pellet were measured, they were 35 mg / piece and 15 mg / (g pellet), respectively, and the handleability was excellent. Further, the solution specific viscosity of the biodegradable resin pellet was 2.74, and an excellent solution specific viscosity retention rate was exhibited. Furthermore, when the residual lactide amount was measured, it was 0.15 weight%.
Further, a 2/1 twill woven fabric was prepared in the same manner as in Example 1. There was no yarn breakage at the spinning stage, and the product could be obtained without problems. When the color tone of the woven fabric was measured, the b value was 6.5, and only a poor-quality fabric colored yellow was obtained. However, when the wear resistance was evaluated, the wear resistance was excellent.

Example 4
Biodegradable resin pellets were obtained in the same manner as in Example 1, except that the speed of the cutter was adjusted so that the particle size of the resulting biodegradable resin pellets was 3 mg / piece.
The obtained biodegradable resin pellet had a b value of 5.0 and exhibited an excellent color tone. Further, the solution specific viscosity of the biodegradable resin pellet was 2.76, and an excellent solution specific viscosity retention rate was exhibited. Moreover, the amount of powder was 40 mg / (g pellet), and sufficient handleability was shown. Furthermore, when the residual lactide amount was measured, it was 0.15 weight%.
Further, a 2/1 twill woven fabric was prepared in the same manner as in Example 1. Although slight yarn breakage was observed in the spinning stage, the product could be obtained at a level where there was no practical problem. When the color tone of the fabric was measured, the b value was 3.8, which was excellent. In addition, when the wear resistance was evaluated, good wear resistance was shown.

Example 5
Biodegradable resin pellets were obtained in the same manner as in Example 1 except that the speed of the cutter was adjusted so that the particle size of the obtained biodegradable resin pellets was 45 mg / piece.
The obtained biodegradable resin pellet had a b value of 5.0 and exhibited an excellent color tone. Further, the solution specific viscosity of the biodegradable resin pellet was 2.76, and an excellent solution specific viscosity retention rate was exhibited. Moreover, the amount of powder was 40 mg / (g pellet), and sufficient handleability was shown. Furthermore, when the residual lactide amount was measured, it was 0.15 weight%.
Further, a 2/1 twill woven fabric was prepared in the same manner as in Example 1. Although slight yarn breakage was observed in the spinning stage, the product could be obtained at a level where there was no practical problem. When the color tone of the fabric was measured, the b value was 3.8, which was excellent. In addition, when the wear resistance was evaluated, good wear resistance was shown.

Comparative Example 3
Biodegradable resin pellets were obtained in the same manner as in Example 1, except that the speed of the cutter was adjusted so that the particle size of the obtained biodegradable resin pellets was 1.5 mg / piece.
The obtained biodegradable resin pellet had a b value of 5.0 and exhibited an excellent color tone. Further, the solution specific viscosity of the biodegradable resin pellet was 2.76, and an excellent solution specific viscosity retention rate was exhibited. Moreover, the amount of powder was 70 mg / (g pellet), and showed sufficient handleability. Furthermore, when the residual lactide amount was measured, it was 0.15 weight%.
Further, spinning was performed in the same manner as in Example 1, but yarn breakage occurred frequently at the spinning stage, and a sample could not be obtained.

Comparative Example 4
Biodegradable resin pellets were obtained in the same manner as in Example 1 except that the speed of the cutter was adjusted so that the particle size of the obtained biodegradable resin pellets was 60 mg / piece.
The obtained biodegradable resin pellet had a b value of 5.0 and exhibited an excellent color tone. Further, the solution specific viscosity of the biodegradable resin pellet was 2.76, and an excellent solution specific viscosity retention rate was exhibited. Moreover, the amount of powder was 35 mg / (g pellet), and showed sufficient handleability. Furthermore, when the residual lactide amount was measured, it was 0.15 weight%.
Further, spinning was performed in the same manner as in Example 1, but yarn breakage occurred frequently at the spinning stage, and a sample could not be obtained.

Example 6
Biodegradable resin pellets were obtained in the same manner as in Example 1 except that the additive was N-stearyl stearamide (SSA).
The obtained biodegradable resin pellet had a b value of 5.1 and exhibited an excellent color tone. Further, the solution specific viscosity of the biodegradable resin pellet was 2.76, and an excellent solution specific viscosity retention rate was exhibited. Further, the amount of powder was 40 mg / (g pellet), and the particle size was 35 mg / piece, indicating good handleability. Furthermore, when the residual lactide amount was measured, it was 0.15 weight%.
Further, a 2/1 twill woven fabric was prepared in the same manner as in Example 1. Although slight yarn breakage was observed at the spinning stage, the product could be obtained without problems. When the color tone of the fabric was measured, the b value was 3.9, which was excellent. In addition, when the wear resistance was evaluated, the wear resistance was excellent.

Example 7
Biodegradable resin pellets were obtained in the same manner as in Example 1 except that the additive was cetyl palmitate (PS).
The obtained biodegradable resin pellet had a b value of 5.3 and exhibited an excellent color tone. Further, the solution specific viscosity of the biodegradable resin pellet was 2.76, and an excellent solution specific viscosity retention rate was exhibited. Moreover, the amount of powder was 42 mg / (g pellet), and the particle size was 35 mg / piece, indicating good handleability. Furthermore, when the residual lactide amount was measured, it was 0.15 weight%.
Further, a 2/1 twill woven fabric was prepared in the same manner as in Example 1. Although slight yarn breakage was observed at the spinning stage, the product could be obtained without problems. When the color tone of the fabric was measured, the b value was 4.0, which was excellent. In addition, when the wear resistance was evaluated, the wear resistance was excellent.

Example 8
Biodegradable resin pellets were obtained in the same manner as in Example 1 except that the kneader setting maximum temperature was 190 ° C. At this time, the calculated value of T × (Tsv−Tm) was 9.9, and the calculated value of Tsv−Tm was 22.
The obtained biodegradable resin pellet had a b value of 6.5, indicating a good color tone. Further, the solution specific viscosity of the biodegradable resin pellet was 2.74, and an excellent solution specific viscosity retention rate was exhibited. Further, the amount of powder was 40 mg / (g pellet), and the particle size was 35 mg / piece, indicating good handleability. Furthermore, when the residual lactide amount was measured, it was 0.18% by weight.
Further, a 2/1 twill woven fabric was prepared in the same manner as in Example 1. The product could be obtained without yarn breakage at the spinning stage. When the color tone of the fabric was measured, the b value was 4.6, which was excellent. In addition, when the wear resistance was evaluated, the wear resistance was excellent.

Example 9
Biodegradable resin pellets were obtained in the same manner as in Example 1 except that the kneader set maximum temperature was 195 ° C. At this time, the calculated value of T × (Tsv−Tm) was 12.2, and the calculated value of Tsv−Tm was 27.
The obtained biodegradable resin pellet had a b value of 10.5 and exhibited a good color tone. Furthermore, the solution specific viscosity of the biodegradable resin pellets was 2.72, indicating an excellent solution specific viscosity retention. Further, the amount of powder was 40 mg / (g pellet), and the particle size was 35 mg / piece, indicating good handleability. Furthermore, the amount of residual lactide was measured and found to be 0.21% by weight.
Further, a 2/1 twill woven fabric was prepared in the same manner as in Example 1. The product could be obtained without yarn breakage at the spinning stage. When the color tone of the woven fabric was measured, the b value was 4.7, which was excellent. In addition, when the wear resistance was evaluated, the wear resistance was excellent.

Comparative Example 5
Biodegradable resin pellets were obtained in the same manner as in Example 1 except that the kneader setting maximum temperature was 205 ° C. At this time, the calculated value of T × (Tsv−Tm) was 16.7, and the calculated value of Tsv−Tm was 37.
The b value of the obtained biodegradable resin pellets was 14.5, and only those that turned yellow could be obtained. The solution specific viscosity of the biodegradable resin pellet was 2.65, and the solution specific viscosity retention rate was good. Further, the amount of powder was 40 mg / (g pellet), and the particle size was 35 mg / piece, indicating good handleability. Furthermore, when the amount of residual lactide was measured, it was 0.55 weight%.
Further, a 2/1 twill woven fabric was prepared in the same manner as in Example 1. The product could be obtained without yarn breakage at the spinning stage. When the color tone of the woven fabric was measured, the b value was 6.2, and the color changed to yellow and the quality was poor. However, the abrasion resistance evaluation of the fabric showed excellent abrasion resistance.

Comparative Example 6
An attempt was made to obtain biodegradable resin pellets by the same method as in Example 1 except that the kneader set maximum temperature was 165 ° C. However, the viscosity of the molten resin was too high, so that the desired biodegradable resin was obtained. Pellets could not be obtained stably.

Example 10
A biodegradable resin pellet was obtained in the same manner as in Example 1 except that the residence time T was 0.3 minutes. At this time, the calculated value of T × (Tsv−Tm) was 3.6, and the calculated value of Tsv−Tm was 12.
The obtained biodegradable resin pellet had a b value of 4.4, indicating an excellent color tone. Further, the solution specific viscosity of the biodegradable resin pellet was 2.77, and an excellent solution specific viscosity retention rate was exhibited. Further, the amount of powder was 20 mg / (g pellet), and the particle size was 35 mg / piece, indicating good handleability. Furthermore, the amount of residual lactide was measured and found to be 0.14% by weight.
Further, a 2/1 twill woven fabric was prepared in the same manner as in Example 1. Although slight yarn breakage was observed at the spinning stage, the product could be obtained without problems. When the color tone of the woven fabric was measured, the b value was 4.2, which was excellent. In addition, when the wear resistance was evaluated, the wear resistance was excellent.

Example 11
Biodegradable resin pellets were obtained in the same manner as in Example 1 except that the residence time T was 1.25 minutes. At this time, the calculated value of T × (Tsv−Tm) was 15, and the calculated value of Tsv−Tm was 12.
The obtained biodegradable resin pellet had a b value of 12.5 and exhibited a sufficient color tone. Furthermore, the solution specific viscosity of the biodegradable resin pellet was 2.68, and an excellent solution specific viscosity retention rate was exhibited. Moreover, the powder amount was 25 mg / (g pellet), and the particle size was 35 mg / piece, indicating good handleability. Furthermore, when the amount of residual lactide was measured, it was 0.65 weight%.
Further, a 2/1 twill woven fabric was prepared in the same manner as in Example 1. Although slight yarn breakage was observed at the spinning stage, the product could be obtained without problems. When the color tone of the woven fabric was measured, the b value was 4.9, which was excellent. In addition, when the wear resistance was evaluated, the wear resistance was excellent.

Example 12
The polyoxyalkylene ether [general formula / R—O— (CH ₂ CH ₂ O) n—H, R / oleyl alcohol or cetyl alcohol, n / 2 to 8, weight average molecular weight / 550] is previously added to polylactic acid P1. 0.03% by weight, 5% by weight of EBA mixed and adhered to polylactic acid P1, and then biodegraded in the same manner as in Example 1 except that the mixture was fed to the kneader at 2000 g / min. Resin pellets were obtained. At this time,
The calculated value of T × (Tsv−Tm) was 5.4, and the calculated value of Tsv−Tm was 12.
The obtained biodegradable resin pellet had a b value of 5.0 and exhibited a sufficient color tone. Further, the solution specific viscosity of the biodegradable resin pellet was 2.76, and an excellent solution specific viscosity retention rate was exhibited. Further, the amount of powder was 20 mg / (g pellet), and the particle size was 35 mg / piece, indicating good handleability. Furthermore, when the residual lactide amount was measured, it was 0.15 weight%.
Further, a 2/1 twill woven fabric was prepared in the same manner as in Example 1. Although slight yarn breakage was observed at the spinning stage, the product could be obtained without problems. When the color tone of the fabric was measured, the b value was 3.8, which was excellent. In addition, when the wear resistance was evaluated, the wear resistance was excellent.

  It is possible to obtain a final product such as a fiber or film having both color tone and wear resistance.

It is a figure explaining the meshing rate of the screw used for this invention. An example of the method of manufacturing a final product using the biodegradable resin pellet obtained by this invention is shown.

Explanation of symbols

La: Screw valley diameter Lb: Screw crest diameter 1: Spinning hopper 2: Extruder 3: Metering pump 4: Spin block 5: Pack 6: Base 7: Chimney 8: Lubricating device 9: Entangling device 10: First go Dead roller 11: Second godet roller 12: Winder 13: Cheese F: Yarn

Claims (6)

Biodegradable resin pellets characterized in that 80% by weight or more is a biodegradable polyester resin and satisfies the following characteristics (A) to (C).
(A) b value: -3 to 13
(B) Particle size: 2-50 (mg / piece)
(C) Fatty acid amide and / or fatty acid ester content: 0.1 to 10 (% by weight)
However, the particle size is an average value calculated from the weight per 100 pellets.   The biodegradable resin pellet according to claim 1, wherein the fatty acid amide is a fatty acid bisamide and / or an alkyl-substituted fatty acid monoamide.   The biodegradable resin pellet according to claim 1 or 2, wherein the biodegradable polyester resin is polylactic acid. When a fatty acid amide and / or a fatty acid ester is added to a biodegradable polyester and kneaded, the total amount of the additive is 0.1 to 10% by weight and satisfies the following formulas (1) to (2): A method for producing biodegradable resin pellets, characterized in that:
T × (Tsv−Tm) ≦ 15 (1)
Tsv−Tm ≦ 30 (2)
T: kneader residence time (min)
Tsv: Maximum temperature set in the kneader (° C)
Tm: melting point of biodegradable polyester (° C.)   When the pellet made of biodegradable polyester and fatty acid amide and / or fatty acid ester are added and mixed in the melt kneader, an organic low molecular weight compound having a film forming ability is previously formed on the surface of the biodegradable polyester pellet. The method for producing biodegradable resin pellets according to claim 4, wherein the biodegradable resin pellets are attached and then mixed with fatty acid amide and / or fatty acid ester.   6. The biodegradable resin pellet according to claim 5, wherein the organic low molecular weight compound having film-forming ability is an ether having a polyoxyethylene chain, and the weight average molecular weight is 400 to 4000. Method.

Images