JP2005213392A - Polyester resin composition and packing band using the same and method for producing the packing band - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a composition of a polyester resin with a high degree of polymerization, to provide a packing band using the same, and to provide methods for producing the composition of the polyester resin with the high degree of polymerization and the packing band respectively. <P>SOLUTION: The composition of the polyester resin with the high degree of polymerization is obtained by blending a polyester resin with a compound having two or more functional groups enabling polymerization by reacting with the hydroxy groups in the polyester molecule and a compound having two or more functional groups enabling polymerization by reacting with the carboxy groups in the polyester molecule. Thus, by using two or more compounds having functional groups bindable to different terminal groups respectively, the composition of the polyester resin with a final degree of polymerization can be raised further, obtaining the polyester resin of excellent properties. The packing band with high degree of polymerization and excellent properties is obtained by using this polyester resin composition. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a polyester resin composition having a high degree of polymerization and a packing band using the same, and relates to a polyester resin resin composition having high strength characteristics mainly composed of a recycled polyester resin.

  Polyester resins, especially polyethylene terephthalate (PET) resins, etc. have excellent properties and are widely used as fibers, films and molded articles. One of the products is a packing band. The band for packing is a band obtained by extruding a melt of a resin into a belt shape and heat-fixing the resin oriented by stretching in the length direction, and exhibits excellent physical strength. It is known that the mechanical properties of such a polyester resin greatly depend on the degree of polymerization, and a high degree of polymerization is required within the range allowed by moldability involving melt viscosity and the like.

  In addition, polyester resins are also actively collected and reused. However, when such a recycled resin is used as a raw material, the degree of polymerization is lower than that of a virgin material due to degradation such as hydrolysis, resulting in low mechanical properties and low physical strength. Not suitable for packing bands.

  Against this background, various studies have been made to increase the degree of polymerization of polyester resins in order to improve mechanical properties. One of the methods is a solid phase polymerization method. The solid phase polymerization method is a method in which the degree of polymerization is increased by heating the polyester at a temperature below its melting point for a long time, but it has a drawback that the productivity is low because a very long time is required.

  In Patent Document 1 and Patent Document 2, a compound having two or more functional groups capable of bonding to the end of a molecule is added and reacted in a molten state to bond two or more polyester molecules to polymerize a polyester resin. A method of increasing the degree has been proposed. This method is a very effective means by which a polyester resin having a high degree of polymerization can be obtained in a short time by simple means of melting and mixing.

JP 11-1115025 A JP-A-63-99228

  However, the methods described in the above documents cannot be said to have sufficiently improved mechanical properties, and further improvement of mechanical properties such as longitudinal crack resistance, which is particularly important when used for packing bands, is desired. It was rare.

  Therefore, the present invention has been made in view of the above problems, and it is intended to provide a polyester resin composition having a high degree of polymerization with excellent mechanical properties, a packing band using the same, and a method for producing the same. In particular, a recycled polyester resin can be used.

  In order to achieve the above object, the present invention is configured as follows. That is, the polyester molecule passes through a compound having two or more functional groups that can be polymerized by reacting with a hydroxyl group in the polyester molecule, and a compound having two or more functional groups that can be polymerized by reacting with a carboxyl group in the polyester molecule. And connected in a straight chain and / or branched chain.

  The polyester resin is obtained by copolymerizing a dicarboxylic acid and a diol through an ester bond, and has a hydroxyl group or a carboxyl group at the end of the molecule. By reacting a compound having two or more functional groups polymerizable in the terminal hydroxyl group or carboxyl group, a plurality of polyester molecules can be polymerized, and the degree of polymerization of the polyester resin can be improved. .

  In the present invention, a compound having two or more functional groups that can be polymerized by reacting with a hydroxyl group in the polyester molecule and a compound having two or more functional groups that can be polymerized by reacting with a carboxyl group in the polyester molecule are respectively used in the polyester resin. It is characterized by mixing. These compounds can improve the degree of polymerization even if blended alone in the polyester resin. However, when used alone, there is a limit in improving the degree of polymerization because the terminal groups that can be bound by each compound are determined. Therefore, by using two or more compounds having functional groups that can be bonded to different terminal groups, the degree of polymerization can be further increased, and a polyester resin having excellent characteristics can be obtained.

  Moreover, according to the method of the present invention, the carboxyl group at the terminal of the polyester molecule can be reduced. The carboxyl group at the terminal affects the heat resistance and heat and moisture resistance, and the smaller the number, the better the physical properties.

  The functional group that can be polymerized by reacting with a hydroxyl group in the polyester molecule is an N-acyl lactam group, and the functional group that can be polymerized by reacting with a carboxyl group in the polyester molecule is an epoxy group, an oxazoline group, or a carbodiimide group. It is characterized by being at least one selected from.

  The functional group that reacts with and bonds to the hydroxyl group at the end of the polyester is preferably an N-acyl lactam group, and a compound having two such functional groups is a bislactam compound. In addition, functional groups that react and bond with carboxyl groups include epoxy groups, oxazoline groups, carbodiimide groups, etc., and compounds include epoxy compounds, oxazoline compounds, carbodiimide compounds, etc. In consideration of cost and the like, an epoxy compound is preferably used.

  The polyester resin is a recycled polyester resin.

  The present invention is extremely effective for a regenerated polyester resin such as a regenerated PET resin whose degree of polymerization is lower than that of a virgin material. PET resin is widely used for various products including PET bottles, and it is popular to collect waste products of these products and use them again as raw materials. However, the degree of polymerization of recycled resin using waste as a raw material is lowered due to deterioration of the resin and the like. Therefore, if this recycled resin is used as it is, its mechanical properties will be low, but according to the present invention, its degree of polymerization is significantly increased and its mechanical properties are comparable to or better than virgin materials. Can increase the range of recycled resin products, and can greatly contribute to resource recycling.

  Moreover, it is good to form the band for packing using the above-mentioned polyester composition.

  The packing band is obtained by extruding a melt of resin into a band and heat-fixing the resin oriented by stretching in the length direction, but its physical strength is large in its degree of polymerization. It is known that it depends, and a high degree of polymerization is required as long as the moldability allows. In addition, it is known that the longitudinal crack resistance indicating how hard the band is to break is also an important physical property value, and the higher the degree of polymerization, the better. That is, according to the present invention, if the degree of polymerization is improved, a packing band with higher strength can be provided. Further, conventionally, it is unsuitable to use a recycled polyester resin for a packing band because of its low physical strength and low vertical cracking resistance, that is, a low polymerization degree. According to the present invention, the degree of polymerization can be sufficiently improved even when a recycled polyester resin is used as a raw material, and a packing band having sufficient longitudinal cracking resistance and physical strength is provided. it can.

  In addition, a polyester resin, a compound having two or more functional groups that can be polymerized by reacting with a hydroxyl group in the polyester molecule, and a compound having two or more functional groups that can be polymerized by reacting with a carboxyl group in the polyester molecule The composition is characterized by being melted by heating and polymerized.

  In the present invention, the polyester resin has an appropriate amount of a compound having two or more functional groups that can be polymerized by reacting with a hydroxyl group in the polyester molecule and two or more functional groups that can be polymerized by reacting with a carboxyl group in the polyester molecule. The compound is mixed, heated and melted to advance the polymerization reaction, thereby increasing the degree of polymerization and reducing the terminal carboxyl group.

  In addition, a polyester resin, a compound having two or more functional groups that can be polymerized by reacting with a hydroxyl group in the polyester molecule, and a compound having two or more functional groups that can be polymerized by reacting with a carboxyl group in the polyester molecule The composition is characterized in that the composition is heated and melted, the polymerized melt is extruded into a strip shape, and the obtained strip is stretched in the length direction and then heat-set.

  A compound having two or more functional groups that can be polymerized by reacting with an appropriate amount of hydroxyl groups in the polyester molecule and a compound having two or more functional groups that can be polymerized by reacting with carboxyl groups in the polyester molecule Then, it is heated and melted to advance the polymerization reaction, and the melt having a high degree of polymerization and a reduced carboxyl group at the terminal is extruded into a strip shape as it is, and the extruded strip is further removed in the length direction by 3 to 3. By stretching at a stretching ratio of about 10 times, the polyester resin can be oriented and the physical strength necessary for the packing band can be expressed. Thereafter, heat may be further applied to fix the heat.

  By such a process, a packing band having excellent mechanical properties and strength can be obtained. Even when the recycled polyester resin is used as a raw material, the degree of polymerization can be sufficiently increased, and a packing band having high strength can be obtained.

  According to the present invention, a polyester resin, a compound having two or more functional groups that can be polymerized by reacting with a hydroxyl group in the polyester molecule, and two or more functional groups that can be polymerized by reacting with a carboxyl group in the polyester molecule. By containing these compounds and polymerizing them, a plurality of polyester molecules can be polymerized, the degree of polymerization of the polyester resin can be improved industrially efficiently, and at the same time the carboxyl group of the terminal group is reduced. be able to. Therefore, the polyester resin composition obtained by the present invention can be excellent in mechanical properties, physical strength, dry heat resistance, wet heat resistance, and the like.

  At this time, by using two or more compounds having functional groups that can be bonded to different terminal groups, the degree of polymerization can be further increased, and a polyester resin having excellent characteristics can be obtained.

  In addition, the present invention is extremely effective for a recycled polyester resin whose degree of polymerization is lower than that of a virgin material, and for a resin whose degree of polymerization is reduced due to deterioration of the resin or heat history during molding. However, the degree of polymerization can be significantly increased and the properties can be compared to virgin materials or better.

  Moreover, if the polyester resin composition of this invention is used for the band for packing, a higher strength packing band can be provided. In addition, a recycled polyester resin may be used as a raw material, and a packing band having sufficient longitudinal crack resistance and physical strength can be provided.

  Embodiments according to the present invention will be specifically described.

  In the examples of the present invention, intrinsic viscosity (IV value: unit dl / g) is used as an index of polymerization degree. For the intrinsic viscosity, the resin was dissolved in a 1: 1 (weight ratio) mixed solvent of phenol and tetrachloroethane, and the intrinsic viscosity was measured at 25 ° C. It has been found that there is a correlation that the IV value increases as the degree of polymerization increases, and that the physical strength and longitudinal crack resistance when formed into a band shape are improved by increasing the degree of polymerization.

  First, the polyester resin is blended with a compound having two or more functional groups that can be polymerized by reacting with a hydroxyl group in the polyester molecule and a compound having two or more functional groups that can be polymerized by reacting with a carboxyl group in the polyester molecule. The above mixture was melted and mixed at a temperature slightly higher than the melting point of the polyester resin. Specifically, the melting temperature is generally 250 ° C. to 300 ° C., and the polymerization reaction may proceed at the temperature.

  The degree of polymerization can be controlled by the melt mixing time, and the kneading time, that is, the reaction time varies depending on the compound to be added and the polyethylene resin. When the reaction time is short, the polymerization is not sufficiently performed. On the other hand, when the reaction time is long, the cleavage reaction of the polyester molecules becomes dominant, so that an appropriate reaction time is required.

  The resin composition that has been melted and reacted to improve the degree of polymerization may be directly molded as a molten material.

  The polyester resin used in the present invention is typified by polyethylene terephthalate (PET) and is preferably used, but is not particularly limited as long as it is a copolymer of a dicarboxylic acid and a diol, The effects of the present invention can be exhibited. Polyethylene terephthalate is a copolymer of terephthalic acid and ethylene glycol. In addition, for example, as dicarboxylic acids constituting the polyester resin, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenylsulfone dicarboxylic acid, diphenoxyethane Dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl ketone dicarboxylic acid, methyl terephthalic acid, methyl isophthalic acid, sulfoisophthalic acid, anthracene dicarboxylic acid, succinic acid, diethyl succinic acid, adipic acid, methyl adipic acid, trimethyl adipic acid, sebacic acid, decane Dicarboxylic acid, dodecanedicarboxylic acid, cyclopentanedicarboxylic acid, cyclohexanedicarboxylic acid, malonic acid, dimethylmalonic acid, glutaric acid, dimethylglutar , Pimelic acid, azelaic acid, suberic acid and the like, and the diol constituting the polyester resin includes trimethylene glycol, tetramethylene glycol, hexamethylene glycol, decamethylene glycol, neopentyl glycol, cyclohexanedimethanol, cyclohexane Examples include diol, polyoxyethylene glycol, polyoxypropylene glycol, polyoxytetramethylene glycol, propanediol, butanediol, pentanediol, hexanediol, neopentylglycol, and the like. Good.

  Moreover, the recycled polyester resin which collect | recovered waste products may be sufficient, and especially PET can be used industrially suitably because recycling is thriving. Further, the polyester resin used in the present invention may be in the form of pellets, or may be a pulverized product of a molded product as long as it is a recycled product.

As a compound having two or more functional groups that can be polymerized by reacting with a hydroxyl group in the polyester molecule mixed with the above polyethylene resin, an N-acyl lactam group can be polymerized by reacting with the hydroxyl group in the compound. A compound having two or more is preferable. Specific examples include bislactam compounds, and the general formula is represented by Formula 1. Among these, R: C = O can be preferably used. Here, n in the formula 1 is an integer, and R is a structure having a hydrocarbon skeleton.

    In addition, functional groups that can be polymerized by reacting with carboxyl groups in the polyester molecule include, for example, epoxy groups, oxazoline groups, carbodiimide groups, etc., and these compounds may have two or more of these functional groups. Specific examples include epoxy compounds, bisoxazolines, and carbodiimides. Among these, a highly versatile epoxy compound is preferably used, which is preferable in terms of cost. As the epoxy compound to be used, those generally used as an epoxy compound can be widely used. The molecule may have a low molecular weight or a high molecular weight. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, bisphenol S type epoxy resin, cycloaliphatic epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin and the like may be used. Moreover, bifunctional epoxy compounds, such as polyalkylene glycol diglycidyl ether and alkylene glycol diglycidyl ether, may be used.

  Further, at this time, an appropriate catalyst may be added to promote the reaction. By adding a catalyst, the ring-opening reaction of bislactam or an epoxy compound or the polymerization reaction with a polyester resin can be promoted, and can be reacted quickly or selectively.

  A compound having two or more functional groups that can be polymerized by reacting with a hydroxyl group in the polyester resin and polyester molecule, a compound having two or more functional groups that can be polymerized by reacting with a carboxyl group in the polyester molecule, and if necessary The catalyst may be melt-mixed and reacted at an appropriate mixing ratio, but at this time, the reaction may be performed directly in a molding machine for final molding, or in a mixing roll or a mixer. May be. Further, preliminary mixing may be performed in advance.

  Moreover, when shape | molding a polyester resin composition in the band for packing, the molten material which carried out the polymerization reaction is extruded from the slit of a cross-sectional shape of a band from the slit corresponding to a cross-sectional shape of a band. Therefore, after being extruded in a strip shape, it is cooled to about 80 ° C. to 200 ° C. in the cooling layer, and then stretched in the length direction. At this time, the stretching ratio is preferably about 3 to 10 times, and is stretched in one or two stages. The stretching may be performed by using at least two pairs of rollers and controlling the stretching ratio by adjusting the speed of the two rollers. Further, by adjusting the interval between the rollers, the thickness can be kept constant, and further, stretching can be performed in the lateral direction. The stretched band-like product is heat-set at about 100 ° C. to 250 ° C. for 1 to 10 seconds, and if necessary, the surface is embossed and wound up to obtain a product.

  When the packing band is formed as described above, the polymerization reaction is allowed to proceed to about 0.8 to 1.2 in terms of the IV value regardless of whether the virgin material or the recycled polyester resin is used. Well, it is possible to obtain a packing band having sufficient mechanical properties and physical strength.

  The shape of the packing band of the present invention is not particularly limited as long as it has a length that can be used for binding, and includes a tape shape, a ribbon shape, a string shape, a belt shape, and the like. The thickness is preferably 100 μm to 2000 μm and the width is 3 to 1500 mm.

  Embodiments according to the present invention will be described below with reference to examples.

(Example 1)
Two or more functional groups that can be polymerized by reacting with hydroxyl groups in the polyester molecule with respect to 100 parts by weight of recycled polyester resin (mainly composed of PET resin. Initially IV value: 0.763) made of flaky waste. As the compound having 0.3 parts of carbonylbiscaprolactam which is bislactam and having two or more functional groups which can be polymerized by reacting with the carboxyl group in the polyester molecule, glycidyl ester epoxy resin 1.0 which is an epoxy compound Mixed. These were put into a plast mill, melted and polymerized at 280 ° C. while kneading at 50 rpm. At this time, when the melt-kneading time was 4 minutes, the IV value was the highest, and the polyester resin composition was obtained by taking out at this point. The IV value of this polyester resin composition was 0.928.

(Comparative Example 1)
Two or more functional groups that can be polymerized by reacting with hydroxyl groups in the polyester molecule with respect to 100 parts by weight of recycled polyester resin (mainly composed of PET resin. Initially IV value: 0.763) made of flaky waste. As a compound having 0.6 parts of carbonyl biscaprolactam, they were put into a plastmill, melted and subjected to a polymerization reaction at 280 ° C. while kneading at 50 rpm. At this time, when the melt-kneading time was 9.5 minutes, the IV value was the highest, and it was taken out at this point. The IV value of this polyester resin composition was 0.790.

(Comparative Example 2)
Glycidyl ester is a compound having two or more functional groups that can be polymerized by reacting with a carboxyl group in a polyester molecule with respect to 100 parts by weight of recycled PET resin (initial IV value: 0.763) in which the waste product is flaked. 1.0 parts of epoxy resin was mixed, and these were put into a plastmill, melted, and polymerized at 280 ° C. while kneading at 50 rpm. At this time, when the melt-kneading time was 3 minutes, the IV value was the highest, and it was taken out at this point. The IV value of this polyester resin composition was 0.873.

  As described above, the polyester resin has a compound having two or more functional groups that can be polymerized by reacting with a hydroxyl group in the polyester molecule, and a compound having two or more functional groups that can be polymerized by reacting with a carboxyl group in the polyester molecule The polyester resin composition to which is added exhibits a much higher IV value, that is, a higher degree of polymerization than when each compound is added alone.

(Example 2)
Next, the same mixture as in Example 1 was put into a packing band extruder, set so that the melt-kneading time was 280 ° C. and 4 minutes, and the polymerization reaction was allowed to proceed to obtain the molten resin. Was extruded as it was to form a band-like product. The extruder had a rectangular mouthpiece, a width of 40 mm and a thickness of 2 mm. The extruded molten resin was once cooled to 100 ° C. and then stretched about 5 times in the length direction. After stretching, the film was heat-set at 200 ° C. and wound after cooling. The packing band thus obtained had a width of 15 mm and a thickness of 0.5 mm.

As described above, the polyester resin has a compound having two or more functional groups that can be polymerized by reacting with a hydroxyl group in the polyester molecule, and a compound having two or more functional groups that can be polymerized by reacting with a carboxyl group in the polyester molecule Is added to form a packing band, whereby a packing band having a high degree of polymerization and excellent characteristics can be obtained.

Claims (10)

The polyester molecule is directly bonded via a compound having two or more functional groups that can be polymerized by reacting with a hydroxyl group in the polyester molecule and a compound having two or more functional groups that can be polymerized by reacting with a carboxyl group in the polyester molecule. A polyester resin composition characterized by being linked in a chain and / or branched form. The functional group that can be polymerized by reacting with a hydroxyl group in the polyester molecule is an N-acyl lactam group, and the functional group that can be polymerized by reacting with a carboxyl group in the polyester molecule is selected from the group consisting of an epoxy group, an oxazoline group, and a carbodiimide group. The polyester resin composition according to claim 1, wherein the polyester resin composition is at least one. The polyester resin composition according to claim 1 or 2, wherein the polyester is a recycled polyester resin. A packing band comprising the polyester resin composition according to claim 1. A composition comprising a polyester resin, a compound having two or more functional groups that can be polymerized by reacting with a hydroxyl group in the polyester molecule, and a compound having two or more functional groups that can be polymerized by reacting with a carboxyl group in the polyester molecule A method for producing a polyester resin composition, wherein the composition is polymerized by heating and melting. The functional group that can be polymerized by reacting with a hydroxyl group in the polyester molecule is an N-acyl lactam group, and the functional group that can be polymerized by reacting with a carboxyl group in the polyester molecule is selected from the group consisting of an epoxy group, an oxazoline group, and a carbodiimide group. The method for producing a polyester resin composition according to claim 5, wherein the polyester resin composition is at least one. The method for producing a polyester resin composition according to claim 5 or 6, wherein the polyester is a recycled polyester resin. A composition comprising a polyester resin, a compound having two or more functional groups that can be polymerized by reacting with a hydroxyl group in the polyester molecule, and a compound having two or more functional groups that can be polymerized by reacting with a carboxyl group in the polyester molecule A method for producing a packing band, wherein the melt is heated and melted, the polymerized melt is extruded into a strip shape, and the obtained strip is stretched in the length direction and then heat-fixed. The functional group that can be polymerized by reacting with a hydroxyl group in the polyester molecule is an N-acyl lactam group, and the functional group that can be polymerized by reacting with a carboxyl group in the polyester molecule is selected from the group consisting of an epoxy group, an oxazoline group, and a carbodiimide group. 9. The method of manufacturing a packing band according to claim 8, wherein the packing band is at least one. The method for producing a packing band according to claim 8 or 9, wherein the polyester is a recycled polyester resin.