JP2008138192A - Polyester resin composition, manufacturing method thereof, crystallization accelerator for polyester resin, and molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a crystallization accelerator for a polyester resin which is excellent in compatibility with a polyester resin such as polylactic acid that is slow to crystallize after molding, allows the molding to be free from getting turbid caused by a crystallization core agent, keeps the molding in translucency to have only light scattering caused by cryatallization of the resin, and accelerates the polyester resin to crystallize after molding. <P>SOLUTION: The crystallized polyester resin composition comprises at least one polyester resin A crosslinked by at least one radical generator and at least one non-crosslinked polyester resin B that is same to or different from the above polyester resin, wherein the resin A and the resin B are homogeneously melted to mix and crystallize. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  In the present invention, organic free radicals (hereinafter sometimes referred to as “radicals”) may be used for polyester resins (resins having a polyester chain), particularly aliphatic polyester resins, especially polyester resins mainly composed of plant-derived materials. The present invention relates to a crystallized polyester resin composition having improved physical properties obtained by mixing and kneading a crystal polyester resin cross-linked with a generator, a production method thereof, a crystallization accelerator for polyester resin, and a molded product.

  In recent years, instead of petroleum-derived polymer materials due to fossil resource depletion problems and environmental impact, polymer materials that use plant-derived raw materials as renewable polymer materials, so-called biomass plastics, can reduce environmental impact. Has attracted attention as a new material. A typical example thereof is polylactic acid, but the polylactic acid is a crystalline polymer itself, but the heat resistance of the molded product is as low as 50 ° C to 55 ° C. When heated above this temperature, there was a defect that the molded product was deformed. This is because the crystallization speed of polylactic acid after melt molding is extremely slow. In the state where the polylactic acid melted in the molding machine is demolded, the crystallization of the polylactic acid molded product is almost advanced. Because there was not. As an improvement method thereof, there has been carried out a method in which fine powder of inorganic substance such as talc is added to polylactic acid as a crystal nucleating agent to promote crystallization of polylactic acid after molding and demolding of polylactic acid (Patent Document 1, 2). However, since these crystal nucleating agents are inorganic substances, they have defects such as lowering the transparency of the polylactic acid molded product.

Japanese Patent No. 3410075 JP 2004-269588 A

  The object of the present invention is excellent in compatibility with a polyester resin such as polylactic acid having a low crystallinity after molding, and there is no white turbidity of the molded product due to the crystal nucleating agent, and the molded product is light scattering by crystallization of the resin. By providing a crystallization accelerator for a polyester resin that maintains the translucency of only the polyester and accelerates the crystallization speed of the polyester resin after molding, a polyester resin composition containing the accelerator, a method for producing the same, and a molded product is there.

  As a result of intensive studies to achieve the object of the present invention, the present inventors have kneaded a cross-linked polyester resin with a non-cross-linked polyester resin as a crystallization accelerator, thereby including a resin including the non-cross-linked polyester resin. It was found that crystallization of the entire composition was remarkably promoted, and the present invention was completed.

  That is, the present invention relates to at least one polyester resin A (hereinafter sometimes simply referred to as “resin A”, “crosslinked resin A”, or “crystallization accelerator”) crosslinked with at least one radical generator. And at least one non-crosslinked polyester resin B that is the same as or different from the polyester resin (hereinafter sometimes referred to simply as “resin B” or “non-crosslinked resin B”), and both the resin A and the resin B are uniform. There is provided a crystallized polyester resin composition characterized by being melt-mixed and crystallized.

  In the present invention, at least one radical generator is mixed with at least one non-crosslinked polyester resin A ′ (hereinafter sometimes simply referred to as “resin A ′” or “non-crosslinked resin A ′”). The mixture is kneaded at a temperature equal to or higher than the decomposition temperature of the radical generator to crosslink the resin A ′, and then cooled to crystallize the resin with at least one resin A. Provided is a method for producing a crystallized polyester resin composition, which is mixed with a crosslinked resin B, heated and kneaded, and then cooled and crystallized.

  In the present invention, the resin A or the resin B is a polycondensate of at least one hydroxycarboxylic acid (preferably having 1 to 18 carbon atoms), at least one lactone (preferably having 3 to 6 carbon atoms). Or at least one aliphatic polycarboxylic acid (preferably 2-9 carbon atoms) or aromatic polycarboxylic acid (preferably 6-12 carbon atoms) and at least one aliphatic polyol (preferably Is preferably a polycondensate with 2 to 6 carbon atoms or an alicyclic polyol (preferably 4 to 10 carbon atoms).

  In the present invention, the resin A or the resin B is a polylactic acid resin and / or a polysuccinic acid resin; the radical generator is a peroxycarbonate, peroxyester, or diacylper At least one peroxide such as an oxide, a dialkyl peroxide, a peroxyketal peroxide and a hydroperoxide; the mixing ratio of the resin A and the non-crosslinked resin B is A: B: 0.1 to 100 parts by mass per part by mass; The amount of the radical generator used is preferably 0.0005 to 0.01 mol per 100 g of the resin A ′.

  In the present invention, a colorant, a dispersant, an antioxidant, an ultraviolet absorber, a light stabilizer, a flame retardant, an electrification is previously applied to the resin A ′ before crosslinking or to the resin A ′ during kneading. You may mix | blend at least 1 sort (s) of an inhibitor and a filler. The present invention also provides the crystallization accelerator A for the non-crosslinked resin B, comprising the resin A crosslinked and crystallized with the radical generator. The accelerator A may contain a colorant, a dispersant, an antioxidant, an ultraviolet absorber, a light stabilizer, a flame retardant, an antistatic agent, and a filler.

  The present invention also provides a polyester resin molded product obtained by molding the crystallized polyester resin composition of the present invention.

  According to the present invention, it is excellent in compatibility with polyester resins that are slow to crystallize after heating, melting, molding, and demolding, especially polyester resins such as plant-derived biomass plastics such as polylactic acid. Thus, it is possible to provide a crystallization accelerator capable of accelerating the crystallization speed of the molded product after demolding the polyester resin without impairing the transparency of the polyester resin. By adding the crystallization accelerator to the non-crosslinked polyester resin, melt-kneading and molding, the crystallization of the molded product is promoted and a molded product having excellent resin physical properties such as heat resistance can be provided.

  The mechanism by which the crystallization accelerator (crosslinked resin A) of the present invention is promoted for crystallization of the entire resin composition by kneading with the non-crosslinked resin B is based on the results of thermal analysis and X-ray diffraction as follows. It is assumed that

  First, the molecular arrangement of the cross-linked resin A that is cross-linked while the non-cross-linked resin A ′ is melt-kneaded in the extruder is formed by a cross-linked structure between the resin molecules. Despite having the property, the degree of freedom of movement of the molecule of the crosslinked resin A is restricted to some extent. Therefore, for example, in the case of cross-linked poly L-lactic acid which is an example of the cross-linked resin A, it is considered that the three-dimensional arrangement of the cross-linked resin molecules is relatively maintained even after cooling after demolding.

  The cross-linked resin A is melt-kneaded together with the non-cross-linked resin B in an extrusion molding machine so that the cross-linked resin A is uniformly diffused into the non-cross-linked resin B, and after molding, demolded and cooled (water-cooled). However, when the molded product is cooled, the cross-linked resin A crystallizes, and the cross-linked molecular arrangement becomes a template (template) of the mixed non-cross-linked resin B. It is considered that the crystallization proceeds sequentially.

  The crystallization mechanism of the mixture of the resin A and the resin B is based on the action of a crystal nucleating agent which is a conventional solid fine powder (the molten resin is cooled and becomes a metastable crystallization state. The crystallization mechanism in which the existing crystal nucleating agent or the like is used as seeds to form crystals is considered to be a completely different crystallization mechanism.

Next, the present invention will be described in more detail with reference to preferred embodiments.
As the resin A ′ before crosslinking used in the present invention, a conventionally known polyester resin having a number of ester bonds in its structure and further having thermoplasticity, in particular, an aliphatic group that easily undergoes radical crosslinking by peroxide. A polyester resin is mentioned. In particular, a polyester resin obtained by a condensation polymerization or ring-opening polymerization reaction using a raw material such as a plant-derived hydroxycarboxylic acid, lactone, aliphatic or aromatic polycarboxylic acid, or aliphatic or alicyclic polyol as a main component. preferable.

  Examples of the preferable polyester resin include self-condensation polymer of hydroxycarboxylic acid, ring-opening polymer of lactone, and condensation polymer of alkylene glycol and aliphatic dicarboxylic acid (or aliphatic dicarboxylic acid containing aromatic dicarboxylic acid). And polycondensation products of alkylene glycol and aliphatic dicarboxylic acid polyester-carbonate. Examples of the self-condensation polymer of hydroxycarboxylic acid include self-condensation polymer of hydroxycarboxylic acid having 1 to 18 carbon atoms, such as polylactic acid, polyhydroxybutyric acid, 3-hydroxybutyric acid and 3-hydroxyvaleric acid copolymer. The ring-opening polymer of the lactone is a ring-opening polymer of an aliphatic lactone having 3 to 6 carbon atoms, such as polybutyrolactone, polycaprolactone, etc .; the polycondensation product is an aliphatic having 2 to 6 carbon atoms A polycondensation product of a diol and an aliphatic dicarboxylic acid having 2 to 9 carbon atoms such as polybutylene succinate, poly (butylene succinate-adipate) and the like can be mentioned.

  In addition, as the polyester containing an aliphatic ring or an aromatic ring having the above aliphatic polyester as a polymer segment that induces a crosslinked structure, the aliphatic polyester includes an alicyclic group having 4 to 10 carbon atoms. Examples thereof include a dicarboxylic acid unit and a copolymer incorporating an aromatic dicarboxylic acid unit having 6 to 10 carbon atoms, and an alicyclic diol unit having 4 to 10 carbon atoms and 6 to 6 carbon atoms in the aliphatic polyester. And a copolymer incorporating 12 aromatic diol units. For example, poly (butylene succinate-terephthalate), poly (butylene adipate-terephthalate), poly (tetramethylene adipate-terephthalate), poly (butylene-1,4-cyclohexylenedimethyl-adipate), etc .; A polycondensation product of an alkylene glycol and a C2-C9 polyester-carbonate, such as polybutylene succinate-carbonate, may be mentioned, and the above polyester resins may be used alone or as a mixture.

  Among the above-mentioned polyester resins, particularly preferred are polylactic acid resins such as polylactic acid and lactic acid copolymer obtained by polymerizing lactic acid, lactic acid oligomers, and lactides as main components, or polysuccinic acid resins.

  Further, in the present invention, the radical generator used for forming a crosslinked structure in the non-crosslinked resin A ′ is a known radical generation that thermally decomposes to form free radicals and radically crosslinks the non-crosslinked resin A ′. Agent is used. Formation of the crosslinked structure in the non-crosslinked resin A ′ is also performed in the state of the solution or resin dispersion of the non-crosslinked resin A ′, but the most preferable method is a method in which the non-crosslinked resin A ′ is crosslinked in the molten state. . In this method, when the non-crosslinked resin A ′ is kneaded with an extruder and crosslinked, it is preferable to use a radical generator that decomposes at the kneading temperature. The selection of the radical generator cannot be generally defined by the setting of the kneading temperature of the non-crosslinked resin A ′ in the extruder. For example, the kneading temperature of the non-crosslinked resin A ′ is approximately 190 ° C. to 210 ° C. In some cases, a radical generator having a decomposition temperature of about 130 ° C. to 210 ° C. for obtaining a half-life of 1 minute as a guide is preferred.

  The radical generator to be used is preferably an organic peroxide radical generator that easily causes a hydrogen abstraction reaction or a radical addition reaction from the resin molecule of the resin A ′. Specifically, peroxycarbonates such as t-butylperoxyisopropyl carbonate, t-butylperoxyacetate, t-butylperoxy 2-ethylhexanoate, t-butylperoxylaurate, t-butylperoxy Peroxyesters such as oxybenzoate, diacyl peroxides such as benzoyl peroxide, dialkyl peroxides such as di-t-butyl peroxide and di-cumyl peroxide, 2,2-bis (t-butylperoxy) ) One or two or more organic peroxides selected from peroxyketals such as butane and hydroperoxides such as di-isopropylbenzene hydroperoxide are used.

  The amount of the organic peroxide used relative to the resin A ′ is such that a cross-linking point sufficient to constrain the molecular arrangement of the cross-linked resin A used as a crystallization accelerator by cross-linking and maintain the cross-linked state in the resin A ′. It is an amount that can be formed and the cross-linked resin A can be melt-kneaded and uniformly diffused into the non-cross-linked resin B. In the present invention, since the cross-linked resin A used as a crystallization accelerator has a molecular weight distribution of resin molecules, the cross-linked resin A should have a slightly different temperature at which melting starts depending on the molecular weight. In order for A to maintain fluidity when melted, it is desirable that the resin A coexists with crosslinked polyester resin molecules and uncrosslinked polyester resin molecules. Therefore, the amount of the organic peroxide added varies depending on the molecular weight and molecular weight distribution of the resin A ′ to be crosslinked and is not generally determined. However, the amount of organic peroxide used is about 100 g of resin A ′. About 0.0005 mol or more, preferably about 0.001 mol or more. The upper limit of the amount of the organic peroxide added is within a range that does not inhibit diffusion of the resin A in the resin B due to excessive crosslinking of the resin A ′, and is preferably about 0.01 mol or less per 100 g of the resin A ′.

  In this case, in order to effectively perform the crosslinking of the resin A ′ by free radicals due to the decomposition of the peroxide, a conventionally known crosslinking component such as a radical addition polymerizable monomer or oligomer is contained in the raw material of the resin A ′. It may be added. Examples of the crosslinking component include polyfunctional monomers such as polyalkylene glycol di (meth) acrylate having 2 to 6 carbon atoms, glyceryl tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, and one carbon atom. And monofunctional monomers such as -7 dialkyl itaconates.

  The polyester resin composition of the present invention comprises at least one resin A (crystallization accelerator) crosslinked by the radical generator and at least one non-crosslinked resin B that is the same as or different from the resin A, and these Both are characterized by being uniformly melt-mixed and crystallized. The non-crosslinked resin B is at least one polyester resin described above as the resin A ′ and can be used alone or as a mixture. The non-crosslinked resin B is the same as or different from the resin A ′ before crosslinking. However, it is preferable that they are the same.

  The crystallized polyester resin composition of the present invention is obtained by mixing the resin A with the non-crosslinked resin B, heating and kneading in a kneading apparatus, and cooling to crystallize the mixture of the resin A and the resin B. It is done. The crystal formation effect of the cross-linked resin A on the non-cross-linked resin B is assumed to be due to the effect of the cross-linked resin A in the non-cross-linked resin B as described above, but the non-cross-linked resin polyester B by the cross-linked resin A of the present invention. The crystallization effect of is very excellent.

  The compounding ratio in the polyester resin composition of the present invention is 0.1 to 100 mass, preferably 10 to 50 mass for the non-crosslinked resin B with respect to 1 mass of the crosslinked resin A. When the amount of the non-crosslinked resin B used is less than 0.1 parts by mass, the heat melting property and moldability of the resulting polyester resin composition are undesirably lowered. Moreover, when the usage-amount of non-crosslinked resin B exceeds 100 mass parts, although the heat melting property and moldability of the polyester resin composition obtained are favorable, crystallization of the polyester resin molded product after molding and demolding is possible. It becomes slow and it is difficult to obtain a molded product with improved heat resistance.

  In the production of the polyester resin composition of the present invention, when the crosslinked resin A is directly kneaded with the non-crosslinked resin B, first, the crosslinked resin A and the non-crosslinked resin B are mixed at a low magnification, for example, a mass ratio. After kneading at 1: 0.1 to 10 to diffuse the crosslinked resin A into the non-crosslinked resin B at a high concentration in advance, the high concentration compound (crosslinked resin master batch) is diluted with a large amount of the non-crosslinked resin B. After that, it is also preferable to mold into a desired shape.

  For example, in the production of the crosslinked resin A described in Example 1 described later, the amount of peroxide used is 0.0022 mol per 100 g of the non-crosslinked resin A ′. In Example 2, the crosslinked resin A and the non-crosslinked resin B Since the blending ratio of A: B = 10: 90 is about 10-fold dilution, the amount of peroxide used relative to the entire polyester resin composition obtained in Example 2 is 100 g of polyester resin composition. About 0.0002 mol. In Example 3, the blending ratio of the polyester resin composition is A: B = 3: 100, which is about 34 times dilution. In Example 4, the blending ratio of the polyester resin composition is A: B = Since 1:99 and 100-fold dilution, the amount of peroxide used is about 0.00006 mol and 0.000022 mol, respectively, per 100 g of the entire polyester resin composition.

  In the above embodiment, even if the above-mentioned proportion of the organic oxide is allowed to act on the non-crosslinked resin B in an amount corresponding to the polyester resin composition of the present invention without using the crosslinked resin A, the crystal of the resin B This is far below the lower limit of the amount of peroxide used to promote crystallization, and does not show the effect of promoting crystallization of resin B. Therefore, in the present invention, it is surprising that the crystallization is remarkably improved with respect to the entire polyester resin composition by using the peroxide used for the resin A ′ as described above. This is an excellent effect of using the crosslinked resin A as a crystallization accelerator.

  Further, in the polyester resin composition of the present invention, the crosslinked resin A is actually about 10% by mass of the whole composition in Example 2, about 3% by mass of the whole composition in Example 3, and the composition in Example 4. Since it accounts for only 1% by mass of the total, the flow characteristics at the time of melting of the polyester resin composition of the present invention are not significantly different from the flow characteristics at the time of melting of the non-crosslinked resin B. Has an excellent feature that secondary processing such as recovery, reuse and regeneration after use of the polyester resin composition can be easily performed.

  Moreover, it is also preferable to mix | blend the 1 type (s) or 2 or more types of additive with the molding which consists of the polyester resin composition of this invention according to the objective. Examples of the additive include a colorant, a dispersant, an antioxidant, an ultraviolet absorber, a light stabilizer, a flame retardant, an antistatic agent, and a filler.

  There are a method of adding the additive to the crosslinked resin A and a method of adding it to the polyester resin composition of the present invention. As the former method, (a) before kneading the radical generator in the non-crosslinked resin A ′, the above additives and the like are mixed and kneaded in advance, and then the radical generator is added and kneaded, or (B) There is a method of blending the non-crosslinked resin A ′ together with the radical generator and mixing and kneading. The resin A containing the additive thus obtained is mixed with the non-crosslinked resin B, heated and kneaded, cooled and crystallized. In the latter method, the cross-linked resin A, the non-cross-linked resin B, the above additives and the like are mixed, kneaded and processed with a molding machine, and a molded product containing the additives can be obtained.

  The colorant used is a dye selected from dyes, organic pigments, carbon black pigments, inorganic pigments, white organic pigments and inorganic pigments. As the pigment, conventionally known chromatic, black or white pigments are used. For example, azo, polycondensed azo, azo, azomethine, anthraquinone, phthalocyanine, perinone and perylene based azomethine groups are used. Indigo / thioindigo, dioxazine, quinacridone, and isoindolinone pigments, iron oxide pigments, carbon black pigments, titanium oxide pigments, and the like.

  In the present invention, a non-crosslinked resin A ′, a radical generator such as an organic peroxide, an additive and the like are blended, melted and kneaded by a kneader, and the additive is contained in the crosslinked resin A simultaneously with the crosslinking of the resin A ′. Uniformly distributed. The kneading machine used in the present invention includes three rolls, two rolls, a pressure kneader, a Banbury mixer, an open type biaxial continuous kneader, or a screw type single screw extrusion molding machine, rotating in the same direction or different directions. Examples thereof include a twin-screw extruder, a multi-screw extruder, an injection molding machine, a rotor-type kneader, a single-axis or multi-axis continuous kneader, or a combination of these kneaders. These kneaders can freely recombine various segments such as screws, kneading disks, and rotors according to the purpose of kneading, the type of material, and the composition. Further, the length and shape of a cylinder such as an extruder may be freely recombined. These kneaders knead the non-crosslinked resin A ′ with a peroxide or further an additive, and into the non-crosslinked resin A ′ depending on the amount of material supplied, the rotational speed of the screw or rotor, and the temperature of the kneading machine. The dispersion of peroxides or additives can be controlled.

  The crystallized polyester resin composition of the present invention can be used for applications similar to those for which conventional polyester resin moldings have been used. For example, sheets, films, nets, containers, trays, foam materials, food packaging containers, marine products / agricultural products boxes, packaging boxes, transport boxes, electrical products, precision equipment, etc. Buffer material; used in a wide range of applications such as soundproofing and heat insulating materials for buildings and roads. The form of the crystallized polyester resin composition and crystallization accelerator of the present invention may be any form such as powder, pellets, or molded product as long as the above conditions are satisfied.

Next, the present invention will be described in detail with specific examples and comparative examples. In the text, “parts” and “%” are based on mass unless otherwise specified.
Example 1 (Preparation of cross-linked resin A (crystallization accelerator))
After adding 0.4 g (0.0022 mol) of t-butyl peroxyisopropyl carbonate (purity 95%) as a radical cross-linking agent to 100 g of poly L-lactic acid (resin A ′) powder, It knead | mixed with the twin-screw extruder (kneading | mixing temperature of 200 degreeC), it discharged in water in the strand form, cooled, and cut with the pelletizer, and prepared crosslinked resin A pellet.

  Thermal analysis of the A pellet obtained above was performed. FIG. 1 shows a differential scanning calorimetry chart of the A pellet. A sharp endotherm with a peak at 169.2 ° C. indicating melting of the A pellet was shown when the temperature was raised, and a sharp exotherm of 124.7 ° C. was shown when the temperature was lowered. Subsequently, the temperature was raised and lowered again. Similarly, when the temperature was raised, it showed a sharp endotherm indicating the melting of the A pellet at 168.1 ° C. Exhibited exotherm. FIG. 2 shows an X-ray diffraction pattern of a plate molded from the obtained A pellet. As shown in FIG. 2, the diffraction angle 2θ has a sharp peak with a large diffraction intensity at 17.20 °, indicating that the entire plate is crystallized.

Example 2 (resin composition of the present invention and molding process thereof)
10 parts of A pellet (resin A) obtained in Example 1 were mixed with 90 parts of resin pellets of poly L-lactic acid (non-crosslinked resin B), and molded with an injection molding machine to obtain a plate. The plate was subjected to thermal analysis in the same manner as in Example 1. FIG. 3 shows a differential scanning calorimetry chart of the plate. When the temperature was raised, 170.3 ° C. indicating the melting of the plate showed a sharp endotherm, and when the temperature was lowered, the peak showing the crystallization of the plate showed a sharp exotherm of 117.6 ° C. Subsequently, the temperature was raised and lowered again. When the temperature was raised, 166.9 ° C. indicating melting of the plate showed a sharp endotherm, and when the temperature was lowered, 116.8 ° C. showing the crystallization of the plate was also peaked. Showed a sharp fever. FIG. 4 shows an X-ray diffraction pattern of the obtained plate. FIG. 4 shows that 2θ has a sharp peak with a large diffraction intensity at 17.16 °, and the entire plate is crystallized.

Example 3 (Resin composition of the present invention and molding process thereof)
3 parts of crosslinked poly L-lactic acid (crystallization accelerator) resin pellets obtained in Example 1 were mixed with 100 parts of pellets of poly L-lactic acid (resin B), and a plate was obtained with an injection molding machine. The plate was subjected to thermal analysis in the same manner as in Example 1. FIG. 5 shows a differential scanning calorimetry chart of the plate. When the temperature was raised, 172.0 ° C. indicating the melting of the plate showed a sharp endothermic peak, and when the temperature was lowered, the peak showing the crystallization of the plate showed a sharp exotherm of 118.1 ° C. Subsequently, the temperature was raised and lowered again. When the temperature was raised, 168.1 ° C. indicating melting of the plate showed a sharp endotherm, and when the temperature was lowered, 117.2 ° C. showing the crystallization of the plate was also peaked. Showed a sharp fever. FIG. 6 shows an X-ray diffraction pattern of the plate. FIG. 6 shows that 2θ has a sharp peak with a large diffraction intensity at 17.20 °, and the entire plate is crystallized.

Example 4 (resin composition of the present invention and molding process thereof)
1 part of pellets of resin A (crystallization accelerator) obtained in Example 1 was mixed with 99 parts of resin pellets of poly L-lactic acid (resin B) and molded with an injection molding machine to obtain a plate. The plate was subjected to thermal analysis in the same manner as in Example 1. FIG. 7 shows a differential scanning calorimetry chart of the plate. When the temperature was raised, 172.2 ° C. indicating the melting of the plate showed a sharp endotherm, and when the temperature was lowered, the peak showing the crystallization of the plate showed a sharp exotherm of 120.6 ° C. Subsequently, the temperature was raised and lowered again, but when the temperature was raised, the endotherm showed a sharp endotherm with a peak of 168.1 ° C., indicating melting of the plate. It showed a sharp fever. FIG. 8 shows an X-ray diffraction pattern of the plate. FIG. 8 shows that 2θ has a sharp peak with a large diffraction intensity at 17.20 °, and the entire plate is crystallized.

Comparative Example 1 (molded product of resin B only)
Only the resin powder of poly L-lactic acid (resin B) was kneaded with a twin-screw extruder (kneading temperature 200 ° C.) to form resin pellets, and thermal analysis of the pellets was performed. FIG. 9 shows a differential scanning calorimetry chart of the pellet. When the temperature was raised, 172.1 ° C. indicating the melting of the pellets showed a sharp endotherm. Subsequently, the temperature was raised and lowered again. At the time of temperature increase, 108.9 ° C. showed a sharp endotherm indicating crystallization of the peak pellets, but immediately followed by 170.1 ° C. indicating melting of the pellets. Only showed a sharp endothermic endotherm, and it was cooled without showing the exothermic phenomenon due to the crystallization at the time of temperature drop shown in Examples 1, 2, and 3. FIG. 10 shows an X-ray diffraction pattern of the pellet. There is no peak in the diffractogram, indicating that the pellet is in an amorphous (amorphous) state.

Comparative Example 2 (Resin Crystallization with Inorganic Crystal Nucleating Agent)
After adding 11 parts of talc and 1 part of calcium carbonate as inorganic crystal nucleating agents to 100 parts of resin powder of poly L-lactic acid (resin B) and mixing them well, using a twin screw extruder (kneading temperature 200 ° C.) The mixture was kneaded, discharged into water in a strand form, cooled, and cut with a pelletizer to prepare resin pellets containing a crystallization nucleating agent. The pellet was molded by an injection molding machine to obtain a white plate. The white color of the plate is due to the added inorganic crystal nucleating agent.

  The resulting plate was subjected to thermal analysis. FIG. 11 shows a differential scanning calorimetry chart of the plate. According to FIG. 11, 169.6 ° C. indicating the melting of the plate at the time of temperature rise showed a sharp endotherm, and the peak showing the crystallization of the plate at the time of temperature reduction showed a sharp exotherm of 110.1 ° C. Subsequently, the temperature was raised and lowered again. When the temperature was raised, 165.1 ° C. indicating the melting of the plate showed a sharp endotherm, and when the temperature was lowered, the peak was 110.4 ° C. showing the crystallization of the plate. Showed a sharp fever. FIG. 12 shows the X-ray diffraction pattern of the plate obtained above. According to FIG. 12, 2θ showed sharp peaks at 10.08 °, 17.10 ° and 29.22 ° (contrast of relative intensity; 75: 100: 73). X-ray diffraction of talc and calcium carbonate is 10.08 ° and 29.22 °, and 17.10 ° indicates diffraction due to crystallization of poly-L-lactic acid.

Table 1 summarizes the exothermic temperatures derived from the crystallization of the examples using the above polylactic acid. The difference in temperature between the first and second thermal analysis showed a very good reproducibility within 1 ° C. This indicates that the factors that produce poly L-lactic acid crystals are stable.

Examples 5 to 7 (Preparation of cross-linked resin A (crystallization accelerator))
In accordance with Example 1, polybutylene succinate (PBS), polybutylene succinate adipate (PBSA) and poly (ε-caprolactone) (PCL) in Table 2 below were used as non-crosslinked resin B to generate radicals. Three types of cross-linked resins A (crystallization accelerators) were prepared using t-butyl peroxyisopropyl carbonate (BIC) as a peroxide as an agent.

Examples 8 to 10 (Crystal formation and molding of non-crosslinked resin B with resin A (crystallization accelerator))
In the same manner as in Example 2, the non-crosslinked resin B and the crystallization accelerator (resin A) were kneaded in the manner described in Table 3 to form the resin composition of the present invention, and three types of molded products were molded. did. Table 3 shows the crystallization temperature of the resin by differential scanning calorimetry of the molded product.

  In recent years, biomass plastic moldings such as polylactic acid have the disadvantage of low heat resistance, but in the present invention, these polyester resins such as polylactic acid having a low crystallinity have excellent compatibility and transparency. By adding, kneading, and molding a crystallization accelerator that accelerates the crystallization rate without damage, physical properties such as heat resistance can be improved, and a molded product having excellent resin physical properties can be provided. As a result, for example, sheets, films, nets, containers, trays, foamed materials, food packaging containers, marine products and agricultural products, including applications that could not be used due to low heat resistance. Polyesters such as polylactic acid can be used in a wide range of applications such as packaging boxes, transport boxes, cushioning materials for electrical products and precision equipment, soundproofing and heat insulating materials for construction and roads.

Differential Scanning Calorimetry Chart of Crosslinked Resin A Pellets Obtained in Example 1 X-ray diffraction chart of crosslinked resin A pellets obtained in Example 1 Differential scanning calorimetry chart of the plate obtained in Example 2 X-ray diffraction chart of the plate obtained in Example 2 Differential scanning calorimetry chart of the plate obtained in Example 3 X-ray diffraction chart of the plate obtained in Example 3 Differential scanning calorimetry chart of the plate obtained in Example 4 X-ray diffraction chart of the plate obtained in Example 4 Differential scanning calorimetry chart of pellets obtained in Comparative Example 1 X-ray diffraction chart of the pellet obtained in Comparative Example 1 Differential scanning calorimetry chart of the plate obtained in Comparative Example 2 X-ray diffraction chart of the plate obtained in Comparative Example 2

Claims (20)

  It comprises at least one polyester resin A crosslinked by at least one radical generator and at least one non-crosslinked polyester resin B that is the same as or different from the polyester resin, and both the resin A and the resin B are A crystallized polyester resin composition characterized by being uniformly melt-mixed and crystallized.   The polyester resin A or the polyester resin B is a polycondensate of at least one hydroxycarboxylic acid, a ring-opening polymer of at least one lactone, or at least one aliphatic polycarboxylic acid or aromatic polycarboxylic acid. The crystallized polyester resin composition according to claim 1, which is a polycondensate of at least one aliphatic polyol or alicyclic polyol.   The hydroxy aliphatic carboxylic acid has 1 to 18 carbon atoms, the aliphatic lactone has 3 to 6 carbon atoms, the aliphatic polycarboxylic acid has 2 to 9 carbon atoms, and the aromatic polycarboxylic acid The crystallized polyester resin composition according to claim 2, wherein the carbon number of the aliphatic polyol is 6 to 12, the aliphatic polyol has 2 to 6 carbon atoms, and the alicyclic polyol has 4 to 10 carbon atoms. .   The crystallized polyester resin composition according to claim 1, wherein the polyester resin A or the polyester resin B is a polylactic acid-based polyester resin and / or a polysuccinic acid-based polyester resin.   The crystallized polyester resin composition according to claim 1, wherein the radical generator is at least one peroxide.   6. The peroxide is at least one of a peroxycarbonate, a peroxyester, a diacyl peroxide, a dialkyl peroxide, a peroxyketal peroxide and a hydroperoxide peroxide. The crystallized polyester resin composition described in 1.   The crystallized polyester resin composition according to claim 1, wherein a mixing ratio of the crosslinked polyester resin A and the non-crosslinked polyester resin B is B: 0.1 to 100 parts by mass per A part by mass of A.   After mixing at least one radical generator with at least one non-crosslinked polyester resin A ′, kneading the mixture at a temperature equal to or higher than the decomposition temperature of the radical generator to crosslink the polyester resin A ′, At least one cross-linked polyester resin A obtained by cooling and crystallizing the polyester resin is mixed with at least one non-cross-linked polyester resin B, heated and kneaded, and then cooled and crystallized. A method for producing a crystallized polyester resin composition.   The polyester resin A or the polyester resin B is a polycondensate of at least one hydroxycarboxylic acid, a ring-opening polymer of at least one lactone, or at least one aliphatic polycarboxylic acid or aromatic polycarboxylic acid. The method for producing a crystallized polyester resin composition according to claim 8, which is a polycondensation product of at least one aliphatic polyol or alicyclic polyol.   The hydroxy aliphatic carboxylic acid has 1 to 18 carbon atoms, the aliphatic lactone has 3 to 6 carbon atoms, the aliphatic polycarboxylic acid has 2 to 9 carbon atoms, and the aromatic dicarboxylic acid has 10. The crystallized polyester resin composition according to claim 9, wherein the carbon number is 6 to 12, the aliphatic polyol has 2 to 6 carbon atoms, and the alicyclic polyol has 4 to 10 carbon atoms. Production method.   The method for producing a crystallized polyester resin composition according to claim 8, wherein the polyester resin A or the polyester resin B is a polylactic acid-based polyester resin and / or a polysuccinic acid-based polyester resin.   The method for producing a crystallized polyester resin composition according to claim 8, wherein the radical generator is at least one peroxide.   13. The peroxide is at least one of a peroxy carbonate, a peroxy ester, a diacyl peroxide, a dialkyl peroxide, a peroxy ketal peroxide, and a hydroperoxide peroxide. The manufacturing method of the crystallized polyester resin composition as described in any one of.   The method for producing a crystallized polyester resin composition according to claim 8, wherein a mixing ratio of the crosslinked polyester resin A and the non-crosslinked polyester resin B is B: 0.1 to 100 parts by mass per A part by mass of A. .   The method for producing a crystallized polyester resin composition according to claim 8, wherein the amount of the radical generator used is 0.0005 to 0.01 mol per 100 g of the polyester resin A '.   9. The polyester resin A ′ is premixed with at least one additive of a colorant, a dispersant, an antioxidant, an ultraviolet absorber, a light stabilizer, a flame retardant, an antistatic agent and a filler. The manufacturing method of the crystallized polyester resin composition as described in any one of.   When kneading the polyester resin A ′, at least one additive of a colorant, a dispersant, an antioxidant, an ultraviolet absorber, a light stabilizer, a flame retardant, an antistatic agent and a filler is added together with the radical generator. The manufacturing method of the crystallized polyester resin composition of Claim 8 mix | blended.   The crystallization accelerator A for non-crosslinked polyester resin B, comprising the polyester resin A crosslinked and crystallized by the radical generator.   The non-crosslinked polyester resin B according to claim 18, wherein at least one additive of a colorant, a dispersant, an antioxidant, an ultraviolet absorber, a light stabilizer, a flame retardant, an antistatic agent and a filler is blended. Crystallization accelerator A for use.   A polyester resin molded product obtained by molding the crystallized polyester resin composition according to claim 1.

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