JP5109986B2 - Melt spinning method - Google Patents

Description

  The present invention relates to a melt spinning method in which a dendritic polyester is added to a thermoplastic polymer.

  Fibers using thermoplastic polymers such as polyester and polyamide are widely used, and the industrial value is extremely high. And these manufacturing methods employ | adopt melt spinning which extrudes from a thin nozzle | cap | die after melt | dissolving a polymer. At this time, the spinning temperature in melt spinning is determined by the melting point and melt viscosity of the polymer. However, even with the same melting point, the high molecular weight polymer has a higher melt viscosity than the low molecular weight polymer. For this reason, when spinning a high molecular weight polymer, in order to ensure spinnability equivalent to that of a low molecular weight polymer, the spinning temperature is set 10-20 ° C. higher than in the case of a low molecular weight polymer, and the melt viscosity is set. It needs to be lowered. However, with regard to heat resistance, the portion depending on the molecular structure is large, and the heat resistance does not change as the melting point does not change even if the molecular weight is increased. For this reason, when the spinning temperature is increased as described above, polymer thermal decomposition is promoted, and even when a high molecular weight polymer is used, the polymer discharged from the die greatly decreases in molecular weight and is put into a melt spinning machine. The effect of increasing the molecular weight of the polymer is greatly impaired.

  In addition, for polymers with low heat resistance, even if the spinning temperature is precisely controlled, the physical properties may decrease due to thermal decomposition, or the base may become dirty due to the generation of decomposition gas, resulting in a significant decrease in productivity. It was. For this reason, when spinning a high molecular weight polymer or a polymer having low heat resistance, a technique for improving the fluidity of the polymer and lowering the spinning temperature has been desired.

  As a means for reducing the spinning temperature, it is conceivable to reduce the melt viscosity without increasing the spinning temperature by adding a thinning agent. However, what is commonly referred to as a thinning agent is one that lowers the melt viscosity of the entire polymer blend by adding a low molecular weight product. In many cases, the heat resistance of the thinning agent itself is low, and the thinning effect is greatly reduced by volatilization during melt kneading, etc., or the degradation product of the thinning agent greatly increases the properties of the fiber. There have been few examples of successful application to melt spinning up to the present due to damage.

  On the other hand, it has been proposed to improve the fluidity of a polymer by adding a dendritic polymer to a thermoplastic polymer (Patent Document 1). A dendritic polymer has a hyperbranched structure by linking low-molecular-weight main chains via a branching monomer, and the dendritic polymer as a whole becomes a high-molecular-weight polymer. However, the heat resistance is improved. Patent Document 1 discloses that fluidity is improved by adding a non-reactive dendritic polymer with a thermoplastic polymer. However, the main chain portion of the dendritic polymer used in Patent Document 1 is composed of an aliphatic polymer, and the aliphatic polymer has high flexibility of the main chain portion under melting due to its molecular structure. Even if the dendritic polymer and the thermoplastic polymer are non-reactive, there are cases where the molecular chains are often entangled between the dendritic polymer main chain portion and the thermoplastic polymer main chain portion. This is not a major problem because the amount of deformation is small in resin extrusion (injection molding, etc.) and shear deformation is dominant, but it causes serious problems when accompanied by large elongation deformation such as spinning. There was a case. That is, by increasing the degree of entanglement of the molecular chain, the molecular chain of the thermoplastic polymer is hindered from being smoothly stretched and deformed, and the spinnability is significantly impaired. In some cases, the elastic properties of the polymer blend become too strong. In some cases, the spout (ballast) of the discharged polymer immediately below the base becomes large, or a May rain phenomenon occurs in which the polymer is not connected as a yarn, which makes spinning impossible.

  As a method for suppressing the entanglement with the dendritic polymer, a method for suppressing the entanglement with the main chain with the thermoplastic polymer by incorporating a rigid component into the main chain of the dendritic polymer to reduce the flexibility under melting. Has been proposed (Patent Document 2). However, the dendritic polymer described in Patent Document 2 has a problem that the molecular terminal is a carboxylic acid group and the molecular terminal structure is not considered. In some cases, this carboxylic acid group causes hydrolysis of the thermoplastic polymer by autocatalytic reaction under melting, resulting in a decrease in the molecular weight of the added thermoplastic polymer. This phenomenon is not a major problem in extrusion processing (injection molding, etc.) of resins with a short melt residence time, but in melt spinning machines with complicated piping and pack base structures, the residence time may be long or abnormal. Since the staying portion is easily formed, the decrease in the molecular weight of the thermoplastic polymer becomes prominent, which may have a great influence on the spinnability and the mechanical properties of the fiber.

JP 2005-513186 gazette (first and second pages) JP 2008-69339 A (first page)

  The present invention relates to a melt spinning method in which a dendritic polyester is added to a thermoplastic polymer, and the fluidity of the thermoplastic polymer can be improved by adding a dendritic polymer in which a terminal carboxylic acid group has been treated. The melting point of the thermoplastic polymer + 30 ° C. or lower, which makes it possible to lower the spinning temperature as compared with the case where it is not added, and further greatly suppresses the decrease in molecular weight when a high molecular weight polymer or a polymer having low heat resistance is melted. It is an object of the present invention to provide a method for producing a fiber that can stably produce a fiber having characteristics for a long time.

  As a result of intensive studies on the above-mentioned problems of the prior art, it has been found that the problem can be solved by melt-kneading a dendritic polyester with controlled molecular ends into a thermoplastic polymer, and the present invention has been achieved.

That is, the present invention
(1) At least one structural unit selected from an aromatic oxycarbonyl unit (P), an aromatic and / or aliphatic dioxy unit (Q), and an aromatic dicarbonyl unit (R), and a trifunctional organic residue And the content of B is 7.5 to 50 mol% with respect to the total content of P, Q, R, and B, and the terminal carboxylic acid group content is 1 ×. A dendritic polyester having a concentration of 10 ⁻⁴ equivalent / g or less is blended with a thermoplastic polymer so as to have a content of 0.1 to 10 wt%, and then melt-spun at a spinning temperature of the melting point of the thermoplastic polymer + 30 ° C. or less. A melt spinning method characterized by
(2) The melt spinning method according to (1), wherein the dendritic polyester contains a carboxylic acid-reactive monofunctional compound residue,
(3) The melt spinning method according to (2), wherein the carboxylic acid-reactive monofunctional compound is at least one compound selected from orthoester, oxazoline, and epoxide.
(4) When melt spinning, the melt spinning method according to any one of (1) to (3), wherein a single hole discharge rate is 5.0 × 10 ⁻³ to 5.0 g / min,
(5) The melt spinning method according to any one of (1) to (4), wherein the thermoplastic polymer is polyester.

  With the melt spinning method of the present invention, a high molecular weight polymer or a polymer having low heat resistance can be melt-spun with almost no decrease in molecular weight, so that the potential of the polymer used can be fully utilized. Further, since melt spinning can be performed at a spinning temperature as low as the melting point of the thermoplastic polymer + 30 ° C. or lower, generation of decomposition gas is suppressed, for example, contamination of the die is suppressed, and stable production for a long time is possible. Furthermore, in this invention, since the power consumption required for manufacture of a thermoplastic fiber can be reduced, it can contribute also to energy saving and suppression of generation of greenhouse gases.

It is a figure which shows the relationship between a spinning temperature and a spinning pack pressure. It is a figure which shows the relationship between spinning temperature and the discharge polymer IV. It is a figure which shows a melt spinning apparatus.

The dendritic polyester used in the melt spinning method of the present invention is at least one selected from aromatic oxycarbonyl units (P), aromatic and / or aliphatic dioxy units (Q), and aromatic dicarbonyl units (R). The content of B is in the range of 7.5 to 50 mol% with respect to the total of the contents of P, Q, R and B, including the structural unit of the seed and the trifunctional organic residue (B). It is necessary to use a dendritic polyester having a terminal carboxylic acid amount of 1 × 10 ⁻⁴ equivalent / g or less.

  Here, the aromatic oxycarbonyl unit (P), the aromatic and / or aliphatic dioxy unit (Q), and the aromatic dicarbonyl unit (R) are each a structural unit represented by the following formula.

  Here, R1 and R3 are each an aromatic residue. R2 is an aromatic residue or an aliphatic residue. R1, R2, and R3 may each include a plurality of structural units.

  Examples of the aromatic residue include a substituted or unsubstituted phenylene group, naphthylene group, and biphenylene group, and examples of the aliphatic residue include ethylene, propylene, and butylene. R1, R2 and R3 are preferably at least one structural unit selected from structural units represented by the following formulas.

  In the formula, Y is at least one selected from a hydrogen atom, a halogen atom and an alkyl group. In the formula, n is an integer of 2 to 8. As a preferable alkyl group here, C1-C4 is preferable.

  In the dendritic polyester of the present invention, the trifunctional organic residue (B) is bonded to each other directly by an ester bond and / or an amide bond, or via a branch structure part (P), (Q) or (R). The three-branch branched structure is used as the basic skeleton. The branched structure may be formed of a single basic skeleton such as three branches, or a plurality of basic skeletons such as three and four branches, three and five branches may coexist. It is not necessary for all of the polymers to be composed of the basic skeleton, and other structures may be included at the ends, for example, for end-capping. The dendritic polyester may contain a structure in which all three functional groups of B are reacted, a structure in which only two are reacted, and a structure in which only one is reacted. . Preferably, the structure in which all three functional groups of (B) have reacted is preferably 15 mol% or more, more preferably 20 mol% or more, and still more preferably 30 mol% with respect to the whole (B). That's it. The three-branch basic skeleton is schematically shown by the following formula.

  If the content of the trifunctional organic residue (B) is 7.5 mol% or more with respect to the total content of the (P), (Q), (R), and (B), it can be obtained. The obtained dendritic polyester can sufficiently obtain the effect due to the dendritic structure. If the content of B is 50 mol% or less, the gelation reaction can be suppressed without lowering the shear response and the fluidity improving effect. Moreover, since the dendritic polyester dispersion diameter in a thermoplastic polymer can be reduced if it exists in this range, the fluid improvement effect of the dendritic polyester obtained by mix | blending with a thermoplastic polymer will improve. The content of B is preferably 10 to 40 mol%, and it is 15 to 35 from the viewpoint of high shear response, fluidity improvement effect when blended with a thermoplastic polymer, and reduced dispersion diameter of dendritic polyester. More preferably, it is mol%.

  Here, content of (B) is a value with respect to the structural unit which comprises the branch structure and branched structure of dendritic polyester, and does not contain the residue which comprises a terminal structure. Here, the branch structure means a linear polyester structure containing any of (P), (Q), and (R) in the dendritic polyester, and the branched structure means (B ) Means the derived structure.

  The dendritic polyester used in the present invention preferably exhibits molten liquid crystallinity. The term “showing molten liquid crystallinity” means that the liquid crystal state is exhibited in a certain temperature range when the temperature is raised from room temperature. The liquid crystal state is a state showing optical anisotropy under shear.

  In order to exhibit molten liquid crystallinity, the basic skeleton is a structural unit (D) in which the organic residue (B) is composed of a branch structure portion (P), (Q) or (R) as shown by the following formula: It is preferable that it couple | bonds through.

  The trifunctional organic residue (B) is preferably a residue of a compound containing a carboxylic acid group, a hydroxyl group, or an amino group. For example, phloroglucinol, trimesic acid, trimellitic acid, trimellitic anhydride Residues such as acid, α-resorcylic acid, 4-hydroxy-1,2-benzenedicarboxylic acid, and 5-hydroxyisophthalic acid are preferable, and residues of trimesic acid and α-resorcylic acid are most preferable. Is a residue of trimesic acid.

  The aromatic oxycarbonyl unit (P), aromatic and / or aliphatic dioxy unit (Q), and aromatic dicarbonyl unit (R) of the dendritic polyester constitute a branch structure portion between branches of the dendritic polyester. Unit. p, q, and r are the average contents (molar ratio) of the structural units (P), (Q), and (R), respectively. %: Dissolved in a mixed solvent of 50% by weight of deuterated chloroform, nuclear magnetic resonance spectrum analysis of proton nuclei at 40 ° C., and obtained from the peak intensity ratio derived from each structural unit. The average content is calculated from the peak area intensity ratio of each structural unit, and the three decimal places are rounded off.

  The ratio of p to q and the ratio of p to r (p / q, p / r) are preferably in the range of 5/95 to 95/5, more preferably 10/90 to 90/10, It is preferably 20/80 to 80/20. If it is this range, liquid crystallinity is easy to express and it is preferable. It is preferable to set the ratio of p / q and p / r to 95/5 or less because the melting point of the dendritic polyester can be within an appropriate range. Further, it is preferable that p / q and p / r be 5/95 or more because the melted liquid crystallinity of the dendritic polyester can be expressed.

  R1 is a structural unit derived from an aromatic oxycarbonyl unit, and specific examples thereof include a structural unit generated from p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid. A structural unit derived from p-hydroxybenzoic acid is preferred, and a structural unit derived from 6-hydroxy-2-naphthoic acid can be used in combination. Further, structural units derived from aliphatic hydroxycarboxylic acids such as glycolic acid, lactic acid, hydroxypropionic acid, hydroxybutyric acid, hydroxyvaleric acid, and hydroxycaproic acid may be contained within a range not impairing the effects of the present invention.

  R2 is a structural unit derived from an aromatic and / or aliphatic dioxy unit, such as 4,4′-dihydroxybiphenyl, hydroquinone, 3,3 ′, 5,5′-tetramethyl-4,4′-dihydroxybiphenyl. , T-butylhydroquinone, phenylhydroquinone, methylhydroquinone, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 2,2-bis (4-hydroxyphenyl) propane and 4,4′-dihydroxydiphenyl ether, ethylene glycol, Examples include structural units derived from 1,3-propylene glycol, 1,4-butanediol and the like. Preferably, it is a structural unit derived from 4,4′-dihydroxybiphenyl, hydroquinone and ethylene glycol, and includes a structural unit derived from 4,4′-dihydroxybiphenyl and hydroquinone or 4,4′-dihydroxybiphenyl and ethylene glycol. This is preferable from the viewpoint of controlling liquid crystallinity.

  R3 is a structural unit derived from an aromatic dicarbonyl unit such as terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-diphenyldicarboxylic acid, 1,2-bis (phenoxy) ethane-4. , 4′-dicarboxylic acid, 1,2-bis (2-chlorophenoxy) ethane-4,4′-dicarboxylic acid and 4,4′-diphenyl ether dicarboxylic acid. A structural unit derived from terephthalic acid or isophthalic acid is preferred, and when both are used in combination, the melting point can be easily adjusted. Some structural units derived from aliphatic dicarboxylic acids such as sebacic acid and adipic acid may be included.

  The branch structure portion of the dendritic polyester of the present invention is preferably mainly composed of a polyester skeleton, but it is also possible to introduce a carbonate structure, an amide structure, a urethane structure or the like to such an extent that the characteristics are not greatly affected. Among them, it is preferable to introduce an amide structure. By introducing such another bond, compatibility with a wide variety of thermoplastic polymers can be adjusted, which is preferable. As a method for introducing an amide bond, p-aminobenzoic acid, m-aminobenzoic acid, p-aminophenol, m-aminophenol, p-phenylenediamine, m-phenylenediamine, tetramethylenediamine pentamethylenediamine, hexamethylene Diamine, 2-methylpentamethylenediamine, nonamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4- / 2,4,4-trimethylhexamethylenediamine, 5-methylnonamethylenediamine, m-xyl Range amine, p-xylylenediamine, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, bis (4-Aminocyclohexyl Aliphatic, alicyclic or aromatic such as methane, bis (3-methyl-4-aminocyclohexyl) methane, 2,2-bis (4-aminocyclohexyl) propane, bis (aminopropyl) piperazine, aminoethylpiperazine It is preferable to copolymerize such an amine compound. Of these, copolymerization of p-aminophenol or p-aminobenzoic acid is preferred.

  Specific examples of the branch structure portion of the dendritic polyester include structural units derived from p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid, structural units derived from p-hydroxybenzoic acid, 6-hydroxy-2 A structural unit derived from naphthoic acid, a structural unit derived from 4,4′-dihydroxybiphenyl and a structural unit derived from terephthalic acid, a structural unit derived from p-hydroxybenzoic acid, a structure derived from 4,4′-dihydroxybiphenyl Units, structural units derived from terephthalic acid and structural units derived from isophthalic acid, structural units derived from p-hydroxybenzoic acid, structural units derived from 4,4′-dihydroxybiphenyl, structural units derived from hydroquinone, derived from terephthalic acid And a structural unit derived from isophthalic acid, p-hydroxy A structural unit derived from benzoic acid, a structural unit derived from ethylene glycol and a structural unit derived from terephthalic acid, a structural unit derived from p-hydroxybenzoic acid, a structural unit derived from ethylene glycol, derived from 4,4′-dihydroxybiphenyl Structural units and structural units derived from terephthalic acid, structural units derived from p-hydroxybenzoic acid, structural units derived from hydroquinone, structural units derived from 4,4′-dihydroxybiphenyl, structural units derived from terephthalic acid, and 2, Consists of structural units derived from 6-naphthalenedicarboxylic acid, structural units derived from p-hydroxybenzoic acid, structural units derived from 6-hydroxy-2-naphthoic acid, structural units derived from hydroquinone and structural units derived from terephthalic acid Things.

  Particularly preferably, the branch structure part is composed of the structural units (PI), (Q-II), (Q-III), (R-IV) and (R-V) described in the following formula. thing,

Or it is comprised from the structural unit (PI), (Q-II), (R-IV), and (R-VI) described in the following formula.

  When the branch structure portion is composed of the structural units (P-I), (Q-II), (Q-III), (R-IV) and (R-V), the structural unit (P- The content p of I) is preferably 30 to 70 mol%, more preferably 45 to 60 mol%, based on the total p + q + r of each structural unit.

  Further, the content q of the structural unit (Q-II) is preferably 60 to 75 mol%, more preferably 65 to 73, based on the total content q of the structural units (Q-II) and (Q-III). Mol%. Further, the content r of the structural unit (R-IV) is preferably 60 to 92 mol%, more preferably 60 to 70, based on the total content r of the structural units (R-IV) and (R-V). It is mol%, More preferably, it is 62-68 mol%.

  In such a case, it is preferable because the effects of the present invention, such as shear response and the effect of addition to a thermoplastic polymer, are remarkably exhibited.

  As described above, the total content q of the structural units (Q-II) and (Q-III) and the total content r of (R-IV) and (R-V) are substantially equimolar. Although preferred, either component may be added in excess.

  When the branch structure portion is composed of the structural units (PI), (Q-II), (R-IV), and (R-VI), the content of the structural unit (PI) p is preferably from 30 to 90 mol%, more preferably from 40 to 80 mol%, based on p + q + r.

  In addition, the content of the organic residue (B) is 7.5 mol% or more, more preferably 10 mol% or more, further preferably 15%, based on the content of all monomers constituting the dendritic polyester. More than mol%. In such a case, the chain length of the branch structure portion is preferable because the dendritic polyester is suitable for taking a dendritic form. As an upper limit of content of the organic residue B, it is 50 mol% or less, 40 mol% or less is preferable and 35 mol% or less is more preferable.

  The dendritic polyester of the present invention may have a partially crosslinked structure as long as the properties are not affected.

  In the present invention, a method for producing a dendritic polyester can be produced according to a known polyester polycondensation method. A monomer containing at least one structural unit selected from the structural unit represented by R1, a monomer containing at least one structural unit selected from the structural unit represented by R2, and R3 A method of reacting a monomer containing at least one structural unit selected from structural units and a trifunctional polyfunctional monomer, wherein the addition amount (mol) of the polyfunctional monomer is a resin. The method of manufacturing as 7.5 mol% or more with respect to all the monomers (mol) which comprise a glassy polyester is preferable. The addition amount of the polyfunctional monomer is more preferably 10 mol% or more, and further preferably 15 mol% or more. Moreover, as an upper limit of addition amount, 50 mol% or less is preferable, More preferably, it is 35 mol% or less.

  In the above reaction, there is also an aspect in which a trifunctional polyfunctional monomer is reacted after acylating a monomer containing at least one structural unit selected from structural units represented by R1, R2 and R3. preferable. Also preferred is an embodiment in which a polymerization reaction is carried out after acylating a monomer containing at least one structural unit selected from structural units represented by R1, R2 and R3, and a trifunctional polyfunctional monomer. .

An example of producing a dendritic polyester composed of the structural units (PI), (Q-II), (Q-III), (R-IV) and (R-V) and a trimesic acid residue And a preferable production method will be described.
(1) After synthesizing a liquid crystalline polyester oligomer from p-acetoxybenzoic acid, 4,4'-diacetoxybiphenyl, diacetoxybenzene, terephthalic acid and isophthalic acid by deacetic acid condensation polymerization reaction, trimesic acid is added to remove acetic acid A method for producing by polymerization reaction.
(2) A method of producing from p-acetoxybenzoic acid, 4,4′-diacetoxybiphenyl, diacetoxybenzene, terephthalic acid, isophthalic acid and trimesic acid by a deacetic acid condensation polymerization reaction.
(3) p-hydroxybenzoic acid, 4,4'-dihydroxybiphenyl, hydroquinone, terephthalic acid and isophthalic acid are reacted with acetic anhydride to acylate the phenolic hydroxyl group, and then the liquid crystalline polyester is subjected to deacetic acid polycondensation reaction. A method in which an oligomer is synthesized and further trimesic acid is added and subjected to a deacetic acid polymerization reaction.
(4) Acetic anhydride is reacted with p-hydroxybenzoic acid, 4,4′-dihydroxybiphenyl, hydroquinone, terephthalic acid, isophthalic acid and trimesic acid to acylate the phenolic hydroxyl group, and then by deacetic acid polycondensation reaction. How to manufacture.
(5) After synthesizing a liquid crystalline polyester oligomer from a phenyl ester of p-hydroxybenzoic acid, 4,4'-dihydroxybiphenyl, hydroquinone, terephthalic acid diphenyl ester and isophthalic acid diphenyl ester by dephenol polycondensation reaction, trimesic acid was synthesized. In addition, a method of producing by dephenol polycondensation reaction.
(6) A method of producing from phenyl ester of p-hydroxybenzoic acid, 4,4′-dihydroxybiphenyl, hydroquinone, diphenyl ester of terephthalic acid, diphenyl ester of isophthalic acid and phenyl ester of trimesic acid by dephenol polycondensation reaction.
(7) After reacting p-hydroxybenzoic acid, terephthalic acid, isophthalic acid, and trimesic acid with diphenyl carbonate to form phenyl esters, respectively, 4,4′-dihydroxybiphenyl and hydroquinone are added, and dephenol polycondensation reaction is performed. How to manufacture.

  Of these, the production methods (1) to (5) are preferred, the methods (3) and (4) are more preferred, and the production method (4) is most preferred from the viewpoint of chain length control and steric regulation.

  In the production method (4), the amount of acetic anhydride used is preferably 0.95 equivalents or more and 1.10 equivalents or less, and 1.00 equivalents or more and 1.10 equivalents or less in terms of chain length control. The amount is more preferably 08 equivalents or less, and most preferably 1.02 equivalents or more and 1.05 equivalents or less. It is possible to control the terminal group by controlling the amount of acetic anhydride or adding an excess of either a dihydroxy monomer or a dicarboxylic acid monomer.

  In order to increase the molecular weight, an amount corresponding to the amount of carboxylic acid of trimesic acid is added in excess of dihydroxy monomer such as hydroquinone or 4,4′-dihydroxybiphenyl to the dicarboxylic acid monomer, and the carboxylic acid in all monomers is increased. The acid and the hydroxyl equivalent are preferably combined.

  When the deacetic acid polycondensation reaction is performed, a melt polymerization method in which the reaction is carried out at a temperature at which the dendritic polyester melts, optionally under reduced pressure, to distill a predetermined amount of acetic acid and to complete the polycondensation reaction, is preferable. For example, a predetermined amount of p-hydroxybenzoic acid, 4,4′-dihydroxybiphenyl, hydroquinone, terephthalic acid, isophthalic acid, trimesic acid, and acetic anhydride were provided with a stirring blade and a distillation pipe, and a discharge port was provided at the bottom. Charge into the reaction vessel. The mixture is heated with stirring under a nitrogen gas atmosphere to acetylate the hydroxyl group, and then heated to 200 to 350 ° C. to perform a deacetic acid polycondensation reaction to distill acetic acid. Acetic acid is distilled off to 91% of theoretical distillation to complete the reaction.

  As conditions for the acetylation, the reaction temperature is preferably in the range of 130 to 170 ° C. in consideration of the actual production process, and the reaction time is preferably 0.5 to 6 hours.

  The polycondensation temperature is a temperature at which the dendritic polyester is melted, and is preferably a melting point of the dendritic polyester + 10 ° C. or higher. Specifically, a range of 200 to 350 ° C. is preferable. The atmosphere for polycondensation is satisfactory even under atmospheric pressure nitrogen, but a reduced pressure is preferable because the reaction proceeds faster and the residual acetic acid in the system decreases. The degree of vacuum is preferably 0.1 mmHg (13.3 Pa) to 200 mmHg (26600 Pa), more preferably 10 mmHg (1330 Pa) to 100 mmHg (13300 Pa). Note that acetylation and polycondensation may be carried out continuously in the same reaction vessel, or acetylation and polycondensation may be carried out in different reaction vessels.

After the polycondensation reaction is completed, the reaction vessel is kept at a temperature at which the dendritic polyester melts, and is pressurized to, for example, 0.01 to 1.0 kg / cm ² (0.001 to 0.1 MPa), and the bottom of the reaction vessel The dendritic polyester is discharged in a strand form from the discharge port provided in. A mechanism that opens and closes intermittently is provided at the discharge port, and it is also possible to discharge liquid droplets. The discharged dendritic polyester is cooled by passing through air or water, and then cut or pulverized as necessary.

  The obtained pellet-like, granular or powdery dendritic polyester further removes water, acetic acid and the like by heat drying or vacuum drying, if necessary. Further, in order to finely adjust the degree of polymerization, or to further increase the degree of polymerization, solid phase polymerization can also be performed. In the solid phase polymerization, for example, the dendritic polyester obtained as described above is subjected to a temperature range of a melting point of the dendritic polyester from −5 ° C. to a melting point of −50 ° C. (for example, 200 to 300 ° C.) under a nitrogen stream or under reduced pressure. And heating for 1 to 50 hours.

  The polycondensation reaction of the dendritic polyester proceeds even without catalyst, but metal compounds such as stannous acetate, tetrabutyl titanate, potassium acetate and sodium acetate, antimony trioxide, and magnesium metal can also be used.

  The dendritic polyester of the present invention preferably has a number average molecular weight of 1,000 to 40,000, more preferably 1,000 to 20,000, still more preferably 1,000 to 10,000, Preferably it is the range of 1,000-5,000. The number average molecular weight is determined by GPC-LS (gel permeation chromatography-light scattering) using a solvent in which the dendritic polyester is soluble, for example, a pentafluorophenol / chloroform (volume mixing ratio 75/25) mixed solvent as an eluent. ) Method as an absolute molecular weight.

  In the present invention, a monofunctional carboxylic acid can be added to the polymerization system in order to control the molecular weight. By adding a monofunctional carboxylic acid, an excessive polymerization reaction can be suppressed and occurrence of side reactions such as gelation can be suppressed. The monofunctional carboxylic acid is preferably benzoic acid or a derivative thereof from the viewpoints of reactivity, heat resistance and handling properties. Specifically, benzoic acid, 4-tert-butylbenzoic acid, 3-tert-butylbenzoic acid, 4-chlorobenzoic acid, 3-chlorobenzoic acid, 4-methylbenzoic acid, 3-methylbenzoic acid, 2- Methylbenzoic acid, 3,5-dimethylbenzoic acid, 3,4-dimethylbenzoic acid, 2,3-dimethylbenzoic acid, 2,4-dimethylbenzoic acid, 2,5-dimethylbenzoic acid, 2,6-dimethylbenzoic acid Acid, 4-ethylbenzoic acid, etc. can be added. As the addition method, either a method of adding before the start of the polymerization reaction of the dendritic polyester or a method of adding during the polymerization reaction can be selected.

  The reaction method between the carboxylic acid terminal of the dendritic polyester and the carboxylic acid-reactive monofunctional compound is a method of adding it during the polymerization reaction of the dendritic polyester, or after the polymerization reaction of the dendritic polyester, remelting or dissolving in a solvent. Either a method of reacting a dendritic polyester with a carboxylic acid-reactive monofunctional compound can be selected, but from the viewpoint of reactivity and safety with the dendritic polyester, after the polymerization reaction of the dendritic polyester, remelting or It is preferable to use a method in which a dendritic polyester dissolved in a solvent is reacted with a carboxylic acid-reactive monofunctional compound. Alternatively, a method may be used in which a dendritic polyester is blended with a thermoplastic polymer or filler, and a carboxylic acid-reactive monofunctional compound is blended at the same time when molding.

The dendritic polyester thus obtained exhibits excellent melt liquid crystallinity, and the flowability of the thermoplastic polymer can be improved by blending it with the thermoplastic polymer, but the main point of the melt spinning method of the present invention is to be used. The amount of carboxylic acid groups present at the molecular ends of the dendritic polyester is 1 × 10 ⁻⁴ equivalent / g or less. In general, it is known that a carboxylic acid group causes hydrolysis by causing an autocatalytic reaction when a proton is ionized. Further, since the carboxylic acid group produced by hydrolysis further causes a self-catalytic reaction, the polyester greatly reduces the molecular weight, but the same applies to the dendritic polyester used in the melt spinning method of the present invention. In addition, when melt-kneaded with other thermoplastic polymer, in addition to the carboxylic acid group originally possessed by the dendritic polyester, the carboxylic acid group generated by hydrolysis will attack the molecular chain of the thermoplastic polymer, The molecular weight of the discharged polymer is greatly reduced. In addition, due to the presence of many functional groups in the dendritic polyester, depending on the thermoplastic polymer, the molecular structure may change due to a transesterification reaction or the like, which may change the characteristics. Such a phenomenon is not a big problem in extrusion processing (for example, injection molding) with a short residence time, but may be a problem that cannot be ignored in melt spinning with a long residence time. As described in Reference Example 7 described later, the dendritic polyester has a structure having a very large number of carboxylic acid groups of 8.95 × 10 ⁻⁴ equivalents / g when the molecular terminals are not controlled. As a result of diligent studies to apply the effect of improving the fluidity of the dendritic polyester to melt spinning, the present inventors have determined that the amount of carboxylic acid groups present at the molecular ends of the dendritic polyester is 1 × 10 ⁻⁴ equivalent / g or less. If the dendritic polyester satisfying this is found to be able to suppress the hydrolysis of the thermoplastic polymer, the effect of improving the fluidity is great, and by lowering the spinning temperature, the dendritic polyester at the time of melt kneading and the like Hydrolysis of the thermoplastic polymer is suppressed. Therefore, there is no need to consider the adverse effect of adding the dendritic polyester, thermal decomposition is suppressed by simply lowering the spinning temperature, and the molecular weight of the discharged polymer is improved. Moreover, since generation | occurrence | production of decomposition | disassembly gas falls by suppressing thermal decomposition, a nozzle | cap | die stain | pollution | contamination is suppressed greatly and it enables stable spinning for a long time.

  The quantification of the amount of carboxylic acid groups present at the molecular ends of the dendritic polyester can be performed by a neutralization titration method. Dendritic polyester (0.5 g) is dissolved in 10 mL of o-chlorophenol or o-cresol while heating to 90 ° C., cooled, and then 4 mL of chloroform is added. After adding a few drops of bromophenol blue-ethanol solution (0.2% by weight), titration reagent (0.04M potassium hydroxide-methanol solution) was dropped with a burette, and the titration was dropped until the neutralization point was reached. The amount of the terminal carboxylic acid of the dendritic polyester can be calculated from the reagent amount.

  The molecular terminal carboxylic acid group amount of the dendritic polyester used in the melt spinning method of the present invention can be reduced by reacting a carboxylic acid-reactive monofunctional compound. Without impairing the effect of improving the fluidity, the carboxylic acid group at the molecular end can be lowered. Here, the carboxylic acid-reactive monofunctional compound refers to a compound having one functional group in the molecule that can react with carboxylic acid at room temperature or when heated to form an ester, amide, urethane, or urea bond. The carboxylic acid-reactive monofunctional compound reacts with the carboxylic acid group present at the molecular end of the dendritic polyester, and the monofunctional compound is introduced at the molecular end, thereby improving the residence stability and hydrolysis resistance of the dendritic polyester. When it is improved and melt-kneaded with another thermoplastic polymer, the decomposition of the thermoplastic polymer can be suppressed.

  The carboxylic acid-reactive monofunctional compound that can be used in the dendritic polyester of the present invention is one or more compounds selected from orthoesters, oxazolines, epoxides, isocyanates, carbodiimides, and diazo compounds. Orthoesters, oxazolines, epoxides, and isocyanates are preferred from the viewpoints of reactivity with carboxylic acid and handling properties, and orthoesters are particularly preferred from the viewpoint of maintaining a high melting point of the dendritic polyester. It goes without saying that the carboxylic acid-reactive monofunctional compound may be used alone or in combination of two or more carboxylic acid-reactive monofunctional compounds.

Examples of the ortho ester compound include trimethyl orthoacetate, triethyl orthoacetate, tripropyl orthoacetate, tributyl orthoacetate, tribenzyl orthoacetate, trimethyl orthoformate, triethyl orthoformate, tripropyl orthoformate, tributyl orthoformate, orthoformate. Tribenzyl, trimethyl orthopropionate, triethyl orthopropionate, tripropyl orthopropionate, tributyl orthopropionate, tribenzyl orthopropionate, trimethyl orthobenzoate, triethyl orthobenzoate, tripropyl orthobenzoate, tributyl orthobenzoate, ortho And tribenzyl benzoate. Of these, trimethyl orthoacetate, triethyl orthoacetate, trimethyl orthoformate, and triethyl orthoformate are preferable from the viewpoint of reactivity, affinity and handling properties with the dendritic polyester, and prevent the influence on the properties of the thermoplastic fiber. From the viewpoint, trimethyl orthoacetate or triethyl orthoacetate is particularly preferred.
Examples of other carboxylic acid-reactive monofunctional compounds include oxazoline compounds such as 2-methyl-2-oxazoline, 2-ethyl-2-oxazoline, 2-propyl-2-oxazoline, 2-butyl-2-oxazoline. 2-isopropyl-2-oxazoline, 2-isobutyl-2-oxazoline, 2-sec-butyl-2-oxazoline, 2-tert-butyl-2-oxazoline, 2-phenyl-2-oxazoline, 2-biphenyl-2 -Oxazoline is mentioned, and examples of the epoxy compound include ethylene oxide, propylene oxide, butyl glycidyl ether, phenyl glycidyl ether and benzoic acid glycidyl ester.

  Theoretically, end-capping is possible by adding the carboxylic acid-reactive monofunctional compound used for capping the carboxylic acid end to the end group to be blocked. It is preferable to use 1.005 times equivalent or more, more preferably 1.008 times equivalent or more of the organic compound used for terminal blocking with respect to the equivalent amount of the terminal group to be blocked. Moreover, it is preferable that the addition amount of the organic compound used for terminal blockage is 2.5 times equivalent or less. Within such a range, the end-blocking of the dendritic polyester is sufficiently performed, and the carboxylic acid group remains in the system and does not generate gas.

  In the melt spinning method of the present invention, the thermoplastic polymer to which the dendritic polyester is added is, for example, polyester, polyamide, polyphenylene sulfide, polyolefin, polycarbonate, polyester carbonate, polyimide, polyamideimide, polyetherketone, polyetheretherketone, polyfluoride. And vinylidene chloride. Of these, highly versatile polyesters and polyamides, and polyphenylene sulfide having excellent heat resistance and chemical properties are preferable. In particular, in the polyester having low hydrolysis resistance, the effect of controlling the molecular terminal of the dendritic polyester becomes more remarkable. In addition, although the melting point of the high molecular weight polyester having an intrinsic viscosity of 1.0 dL / g or more is not so high, the spinning temperature may be increased by about 10 to 20 ° C. compared to the case of polyester for clothing. This is useful from the viewpoint of maintaining a high molecular weight by inhibiting decomposition and thermal decomposition. In the case of polyamide, in addition to the effect of lowering the spinning temperature by improving the fluidity as described above, the hygroscopicity can be surprisingly reduced by the fine dispersion of the hydrophobic dendritic polyester. Polyamide adsorbs water around the amide group present in the molecular chain due to its hydrophilic property and causes water absorption crystallization. This hygroscopic crystallization also occurs on the spinning line, after winding or after forming a drawn yarn, and causes a phenomenon (longitudinal swelling) of the yarn extending in the fiber axis direction. This longitudinal swelling of the polyamide breaks the winding package of the polyamide unstretched yarn, so that there are significant restrictions on the spinning conditions (especially the spinning speed and winding atmosphere), and special equipment such as a steam conditioner is required. Or In addition, since the dimensional stability of the drawn yarn is deteriorated, the fiber structure such as a woven or knitted fabric is misaligned, and the mechanical properties are particularly negligible in industrial applications such as a decrease in mechanical properties in a wet atmosphere. Regarding the melt spinning method of the present invention, since the hydrophobic dendritic polyester is ultra-finely dispersed in the polyamide, it has a specific effect of greatly suppressing longitudinal swelling by being arranged around the amide group. Is considered to have developed.

  In addition to the above-mentioned polymers, although not general-purpose, polyether species such as polyether ketone, polyether ether ketone, polyimide, and polyvinylidene fluoride usually have a considerably high spinning temperature. In view of the effect of lowering, it is a preferred polymer. In particular, the effect of lowering the spinning temperature is useful for polymers that easily generate corrosive substances and harmful substances such as polyvinylidene fluoride. In the case of a high molecular weight polymer having a molecular weight of 100,000 or more, the effect of suppressing the entanglement of molecular chains is useful. In particular, in the case of a polymer having a high molecular weight but a low thermal decomposition temperature, such as polylactic acid, if the spinning temperature can be lowered, not only the molecular weight decrease due to hydrolysis or thermal decomposition can be suppressed, but also the decomposition gas It is very useful because it can suppress the occurrence of It is also highly useful to use a polylactic acid having a weight average molecular weight of 150,000 or more, or a stereocomplex polylactic acid having an improved melting point, as the thermoplastic polymer, which has a high spinning temperature and is easily pyrolyzed.

  In order to maintain thermal stability, one or more kinds of heat-resistant agents selected from phenol-based compounds and phosphorus-based compounds can be added in advance to the thermoplastic polymer used in the present invention. The amount of the heat-resistant agent added is preferably 0.01 wt% or more, particularly preferably 0.02 wt% or more from the viewpoint of the heat-resistance improving effect. In order to prevent a change in mechanical properties to the obtained fiber, the amount added is preferably 5 wt% or less, and particularly preferably 1 wt% or less. Moreover, it is particularly preferable to use a phenolic compound and a phosphorus compound in combination because of their large heat resistance, thermal stability, and fluidity retention effect.

  As the phenolic compound, a hindered phenolic compound is preferably used. Among them, N, N′-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydrocinnamide), tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane and the like are preferably used.

  Examples of phosphorus compounds include bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol-di-phosphite and bis (2,4-di-t-butylphenyl) pentaerythritol-di-phos. Phyto, bis (2,4-di-cumylphenyl) pentaerythritol-di-phosphite, tris (2,4-di-t-butylphenyl) phosphite, tetrakis (2,4-di-t-butylphenyl)- 4,4'-bisphenylene phosphite, di-stearyl pentaerythritol di-phosphite, triphenyl phosphite, 3,5-dibutyl-4-hydroxybenzyl phosphonate diethyl ester and the like. Among them, those having a high melting point are preferably used in order to reduce the volatilization and decomposition of the heat-resistant agent in the manufacturing process of the thermoplastic fiber.

  In addition, ultraviolet absorbers (eg resorcinol, salicylate), anti-coloring agents (phosphite, hypophosphite, etc.), lubricants and mold release agents (eg stearic acid, montanic acid and metal salts thereof), coloring agents, Ordinary additives such as carbon black, a crystal nucleating agent, a plasticizer and an antistatic agent as a conductive agent or a colorant, or a polymer other than a thermoplastic polymer can be blended.

  In the melt spinning method of the present invention, it is necessary to add the above-described dendritic polyester to the thermoplastic polymer. As this addition method, a known kneading method can be used. For example, a dendritic polyester and a thermoplastic polymer are dried, and a mixture thereof is melted by a single screw or twin screw extruder or the like. A polymer blend can be obtained by kneading at + 30 ° C. or lower.

  The term “drying” as used herein means that the polymer is heated in a sealed container evacuated by a vacuum pump or the like to reduce the amount of water in the polymer. For example, a known vacuum dryer or tumbler type vacuum dryer is used. be able to. Here, the water content of the dendritic polyester and the thermoplastic polymer is 500 ppm or less, preferably 300 ppm or less. In such a range, the moisture brought in at the time of melt-kneading is reduced, so the effect of suppressing thermal decomposition by lowering the spinning temperature according to the present invention is added, with almost no decrease in molecular weight relative to the molecular weight of the polymer introduced, It can be discharged. The moisture content of the polymer can be measured with a known Karl Fischer moisture meter.

  The dried dendritic polyester and thermoplastic polymer are: 1) A method in which the thermoplastic polymer and the dendritic polyester are mixed in the desired addition amount, inserted into an extruder having a kneading function, melt kneaded and then directly spun. 2) First, an addition amount is adjusted so that the dendritic polyester is contained in the thermoplastic polymer at a high concentration by an extruder having a kneading function, and melt-kneading is performed to prepare a master pellet. Then, a method of diluting the master pellet with a thermoplastic polymer so as to obtain a prescribed concentration (master pellet method) can be used. In order to save labor, the former kneaded direct spinning is preferable, but the master pellet method in which the latter dendritic polyester is blended with a thermoplastic polymer is considered in terms of production stability such as improvement in uniformity of the amount added, This is a preferable method.

  The method of adding dendritic polyester to the thermoplastic polymer may be blended (dry blended) before feeding into the extruder separately, or weighed separately with a feeder and inserted directly into the extruder The method of doing is also good. Also, unlike a single-screw extrusion kneader, in a biaxial extrusion kneader, foaming induced in the kneading machine is difficult to escape to the charging side, so that foam may be mixed into the fibers and yarn breakage may occur frequently. For this reason, when using a highly viscous polymer such as a high molecular weight polymer, it is preferable to perform an operation of venting on the discharge side of the biaxial extrusion kneader to remove bubbles. In addition, it is preferable to vent when a piece of gut frequently occurs in the case of master pelletization. In the case of master pelletization with a dendritic polyester blend, it is diluted with a virgin polymer in the spinning process, but at this time, it is preferable to use a biaxial extrusion kneader from the viewpoint of uniformity of the bun-lend. This is because, in the present invention, the degree of good fluidization effect varies depending on the dendritic polyester blend ratio, so if the blend is not uniform in the polymer blend, screw torque, tip pressure, filtration pressure, back pressure of the base, and spinning stress This is because spots such as the above occur and stable spinning may become impossible. When a uniaxial extrusion kneader is unavoidably used, a kneading function such as dull mage is added, and a static kneader is provided near the discharge of the uniaxial extrusion kneader or in the spinning machine or spinning pack to sufficiently homogenize the blend. preferable.

  Here, it is important that the addition amount of the dendritic polyester in the polymer blend is 0.1 to 10 wt%. If it is 0.1 wt% or more, the effect of lowering the spinning temperature due to the fluidity-improving effect of the dendritic polymer will be recognized. Dendritic polyester has a reduced viscosity in a high shear region such as in the mouthpiece hole, so if the amount added is large, it may bleed out to the surface of the polymer blend. As a result, the low-viscosity dendritic polymer is discharged and collected in the form of droplets, and the surroundings of the mouthpiece hole are soiled to disturb the elongation deformation of the polymer before solidification, or the accumulated deteriorated product falls and drops. In some cases, it may encourage cutting. However, if it is 10 wt% or less, the dendritic polyester does not bleed out and is uniformly dispersed, so that the periphery of the mouthpiece hole is not soiled, and the mechanical properties and surface properties of the resulting fiber are changed. There is no. Moreover, 2.0 wt% or less is preferable as a range in which a desired addition amount is secured without any accumulation in the hopper without considering the particle size and friction coefficient of the thermoplastic polymer and the dendritic polyester.

  In the case of resin processing, the polymer blend mentioned here often improves mechanical properties (such as improved elastic modulus) and gas barrier properties by mixing a large amount of inorganic fillers such as glass fibers. In this case, when an inorganic filler is mixed, the filter in the spinning machine may be clogged and the filtration pressure may increase rapidly, or the inorganic filler may be clogged in the spinneret hole and spinning may be impossible. Even if spinning is not possible, the discharge of the polymer from the spinneret hole is not stable, and problems such as frequent thread breakage and deterioration of yarn unevenness may occur. For this reason, in the case of fiberization, unlike resin processing, it is better not to mix the inorganic filler, and even if mixed, it is less than 0.5 wt% with respect to the entire polymer blend. The term “inorganic filler” as used herein means that 80 wt% or more is composed of an inorganic substance, the average diameter in terms of a circle is 10 nm or more, and the average length is 100 nm or more.

  As the spinneret used in the present invention, a known one can be used, and a round hole, a Y hole, a C hole having a deformed hole such as a C hole can also be used. The discharge hole diameter of the die used in the present invention may be determined in consideration of the spinning draft (= take-up speed / discharge linear speed) that allows spinning from the relationship between the single hole discharge amount and the spinning speed. 0.1 to 5.0 mmφ is a standard.

  In the case of obtaining a fine fiber or in the case of using a low viscosity polymer, 0.1 to 0.4 mmφ is suitably used, and in the case of a high viscosity polymer, 0.5 to 5.0 mmφ is suitably used. In consideration of meterability, when the discharge hole diameter is 2.0 mmφ or more, it is preferable to provide a measurement hole with a reduced hole diameter on the discharge hole. The L / D (= hole length / hole diameter) of the discharge hole and the measurement hole depends on the thermoplastic polymer to be used, but is 0.1 to 5.0 as a guideline. 3.0 is preferably used. The number of holes in the discharge hole can be set as a concentric array, a staggered array, or a linear array, and the number of holes that enter the base surface can be set. Since the yarns may interfere with each other and the spinnability may be deteriorated, for example, in the case of a base of 100 mmφ, it is preferable to set the hole to 1 to 200 holes.

  The spinning temperature in the melt spinning method of the present invention needs to be the melting point of the thermoplastic polymer to which the dendritic polyester is added + 30 ° C. or lower. Thermoplastic polymers melt at a temperature above the melting point, and fluidity occurs. Generally, the melting point has a profile with a width with respect to temperature, and in order to ensure fluidity that can generally be melt-spun. Therefore, it was necessary to set the spinning temperature higher than the melting point by 30 ° C. or more. However, when the spinning temperature is excessively increased, the thermal decomposition proceeds greatly, so that there is a problem that the molecular weight of the injected thermoplastic polymer is greatly reduced and the expected mechanical properties cannot be obtained. On the other hand, in the melt spinning method of the present invention, since the dendritic polyester described in claim 1 is added, spinning is possible even if the spinning temperature is set low due to the effect of improving fluidity. . The spinning temperature mentioned here means the temperature of the spinning head that discharges the molten polymer as shown in FIG. 3, and it goes without saying that the spinning pack and the base included therein are also controlled to the same temperature. . Also, it is preferable to set the temperature of the extrusion apparatus until it is guided to the spinning head to be low from the viewpoint of maintaining the molecular weight. With the melt spinning method of the present invention, melt spinning can be performed without any problem if the melting point is not higher than 30 ° C. Can do. Since the dendritic polyester used in the melt spinning method of the present invention has no influence on the melting point drop of the thermoplastic polymer, the lower limit of the spinning temperature is the melting point of the thermoplastic polymer, and the melting point of the thermoplastic polymer + 10 ° C. If so, melt spinning can be performed without any problem.

  In the melt spinning method of the present invention, the melting point of the thermoplastic polymer serving as a reference for the spinning temperature means the peak top temperature of the melting peak observed by differential scanning calorimetry (DSC). As a specific measuring method, This can be done as follows. That is, 10 mg of a thermoplastic polymer is weighed as a sample, sealed in an aluminum pan, placed in a DS Instruments 2920 Modulated DSC manufactured by TA Instruments, and measured at a temperature rising rate of 16 ° C./min. Then, the peak top temperature of the melting peak of the polymer at 2nd run is obtained as the melting point of the polymer.

The take-up speed in the present invention varies depending on the physical properties of the thermoplastic polymer and the purpose of the fiber, but is about 500 to 6000 m / min. In particular, when a high molecular weight polymer is used, it is generally better to take the undrawn yarn as a low orientation. Therefore, it is preferable to set to 500 to 1500 m / min. In this case, the single-hole discharge amount may be set to 5 × 10 ^{−3 to} 5.0 g / min. The discharge rate is preferably 0.01 to 5.0 g / min.

  The polymer blend of the thermoplastic polymer and the dendritic polyester thus melt-kneaded is discharged through a thin die hole as in a known melt spinning method, cooled and solidified, and taken up by a take-up roller. The taken-up or wound-up fibers pass through a post-processing step in order to give a physical property that can withstand practical use, in order to obtain a drawing process or a fiber structure. The single yarn fineness of the fiber is preferably 0.1 to 50 dtex. Further, the effects of the present invention work effectively in the production of fibers having a single yarn fineness in such a range as described below.

  In the case of a very fine single yarn fineness of 0.1 to 2 dtex, it can be processed into artificial leather or suede knitted fabric. In spinning of these fibers, the take-up speed is 1000 to 2000 m / min because the spinnability such as winding property is low, and the single-hole discharge rate is very low such as 0.5 g / min or less. Since spinning is performed with a single hole discharge amount, the residence time is four times or more considering that a general clothing fiber has a single hole discharge amount of about 2 g / min. As the residence time increases, the molecular weight of the discharged polymer decreases, so the viscosity decreases, and a drip in which the polymer accumulates in the droplets is likely to occur near the discharge hole. It is one of the factors that make it difficult. Needless to say, the strength and elongation characteristics of the obtained fiber are low, and there is a case where the wear resistance of artificial leather or the like is lowered. On the other hand, in the melt spinning method of the present invention, since the spinning temperature can be lowered, the above-described molecular weight reduction is suppressed, drip hardly occurs, and fine fiber with excellent mechanical properties can be obtained. Furthermore, the effect of increasing the molecular weight of the discharged polymer can increase the spinnability, and it becomes possible to perform spinning at a high take-up speed of 3000 m / min or more, which contributes to improving productivity. be able to.

  In the melt spinning method of the present invention, in order to obtain a fiber having a single yarn fineness of 0.1 to 2 dtex, the single-hole discharge rate can be discharged in a range of 0.05 to 2.0 g / min. In view of proper discharge meterability, the single-hole discharge rate is preferably 0.01 to 1.0 g / min. In order to obtain a fine fineness, the strength of the multifilament is low, so the spinning tension should be low. Considering the spinning draft (= take-up speed / discharge linear speed) that greatly affects this, the base of the die to be used The hole diameter is preferably 0.1 to 0.4 mmφ. In addition, since the single hole discharge amount is low, the hole diameter is preferably 0.1 to 0.25 mmφ in consideration of the meterability of the discharge amount. The polymer discharged in this way is solidified by cooling.

  In the melt spinning method of the present invention, if the spinning temperature is equal to or higher than the melting point of the thermoplastic polymer + 10 ° C., stable ejection is ensured, and therefore, the spinning temperature can be set lower by 10-20 ° C. than normal spinning. For this reason, since the temperature of the yarn discharged from the base is also lower than usual, the cooling of the yarn becomes more effective. For this reason, the addition of dendritic polyester is highly preferred in fine fiber spinning, where effective cooling of the yarn is important for stable spinning. As a cooling device, if there is a known uniflow type cooling device, spinning can be performed without any problem. However, it is preferable to actively cool immediately after discharge by a known annular chimney or the like because the uniformity of the fiber diameter can be further improved. . The fibers to which the oil agent has been solidified can be taken up at a take-up speed of 1000 to 5000 m / min depending on the desired fineness and mechanical properties. The taken-up fibers may be wound once or subsequently stretched under the stretching conditions described later to further reduce the fineness, improve the mechanical properties, or may be used as they are.

  The fibers having a single yarn fineness of 2 to 30 dtex can be widely applied not only for clothing but also for industrial uses such as tire cords, ropes and industrial knitted fabrics. In the case of apparel use, it is taken up at a take-up speed of 2000 to 6000 m / min, wound once or subsequently stretched by a roller 1.1 to 3.0 times heated to a glass transition temperature or higher, and finally a single yarn fineness The drawn yarn is about 1 to 10 dtex. In the case of industrial use, generally, the take-up speed is 3000 m / min or less, and the take-up speed is once taken up or subsequently stretched with a roller heated to a glass transition temperature or higher, and finally the single yarn fineness is about 3 to 15 dtex. Of drawn yarn. In the melt spinning method of the present invention, when spinning these fibers, the spinning temperature can be set low even when the polymer used is very high molecular weight as in Example 2 described later, which is effective in improving the mechanical properties. For this reason, since the fineness or the number of fibers for imparting the same strength to the knitted fabric can be reduced in the clothing application as well as in the industrial application used under severe conditions, it is effective for thin fabrics and the like. Further, as is apparent from a comparison between Example 17 and Comparative Example 7 described later, in the melt spinning method of the present invention, the spinning temperature can be lowered, and therefore, the die contamination can be suppressed. If the base becomes dirty, it is necessary to clean the base or replace the pack, and production will be interrupted. During this time, it is not possible to stop the polymer discharge or the heating of the spinning machine, and it is preferable to suppress the contamination of the base as much as possible from the viewpoint of suppressing the generation amount of production waste and saving energy, and it is effective for this suppression. Can also be mentioned as a remarkable effect of the present invention.

  In the melt spinning method of the present invention, in order to obtain a fiber having a single yarn fineness of 2 to 30 dtex, the single-hole discharge rate can be discharged in the range of 0.5 to 5.0 g / min, and the stability of spinning. If it considers, it is preferable to set it as 0.5-3.0 g / min. As for the hole diameter of the die, a diameter of 0.1 to 5.0 mmφ can be used, but stable spinning properties can be ensured by setting a spinning draft (= take-off speed / discharge linear speed) according to the thermoplastic polymer to be used. Preferably, for example, if the thermoplastic polymer is a garment grade polymer, the hole diameter of the die may be 0.1 to 0.5 mmφ, and the take-up speed may be 1000 to 6000 m / min. In this case, the spinning speed is generally 500 to 3000 m / min. At this time, the diameter of the nozzle hole is preferably 0.3 to 1.0 mmφ. Particularly for use in tire cords and the like, if the take-up speed is 1000 m / min or more and microcrystals are formed in advance in the undrawn yarn stage, the thermal shrinkage rate of the drawn yarn can be reduced. With respect to the spinning temperature, if the spinning temperature is higher than the melting point of the thermoplastic polymer + 10 ° C., stable ejection is ensured. The taken-up fibers can be imparted with desired mechanical properties by winding them once or subsequently adjusting the drawing conditions described later.

  For fibers having a single yarn fineness of 20 to 50 dtex, for example, it can be used as a raw yarn for monofilaments for screen wrinkles. In this application, in order to obtain a high elastic modulus and fineness, a take-up speed of 500 to 1500 m / min is used as a low-oriented undrawn yarn, and it is wound up by a roller once wound or subsequently heated to a glass transition temperature or more 3.0 times or more. Is finally drawn into a drawn yarn having a single yarn fineness of 4 to 15 dtex. In these spinnings, a high molecular weight polymer is used because of mechanical properties, and it is necessary to set the spinning temperature higher than when spinning a clothing grade polymer. Furthermore, although the single-hole discharge amount can be set large, the base used for winding up as a monofilament is often 10 holes or less, and even in this case, the residence time becomes long. In this case, it goes without saying that the molecular weight of the discharged polymer is lowered due to the effects of a high spinning temperature and a long residence time. However, a gel-like material caused by a deteriorated polymer may be mixed in the discharged polymer. When this gel-like material is mixed, it is difficult to increase the fineness and high modulus required for high-definition printing due to deterioration of stretchability. Since the location where the mark exists is a printing defect, it may cause a problem that cannot be ignored, such as being unable to be used as a product at all. In the melt spinning method of the present invention, even if it is a high molecular weight polymer, the spinning temperature can be lowered, so that it effectively acts to suppress the generation of this gel.

  In the melt spinning method of the present invention, fibers having a fineness of 50 dtex or more can be collected by spinning with a large discharge amount due to the effect of improving fluidity. However, in this case, the cooling is not completed by the take-up roller, and the yarn swings. Therefore, the single yarn fineness is preferably set to 50 dtex or less.

  The single yarn fineness referred to here is the total fineness by taking the fibers collected after being taken up as multifilaments or monofilaments into a 100 m small casserole by a measuring machine and multiplying the weight by 100 times. It is a value calculated as the single yarn fineness by dividing this total fineness by the number of filaments.

  In order to obtain fiber properties and fineness suitable for practical use, it is preferable to perform stretching. However, in the present invention, the taken-up fiber may be once wound and then drawn in a separate process, or continuously after taking-up. Stretching may be performed. However, when stretching, it is particularly preferable to set the preheating temperature appropriately. This is because the dendritic polyester used in the present invention may have a softening temperature such as a glass transition temperature higher than that of a thermoplastic polymer, for example, a normal preheating temperature of PET (glass transition temperature: 70 ° C.) of 85 to 95 ° C. On the other hand, the dendritic polyester may behave as a foreign substance during the drawing process, resulting in a reduction in the toughness of the drawn yarn. This effect is particularly prominent as the film is stretched at a high magnification. For this reason, even if the addition amount of dendritic polyester is trace amount, it is preferable to set preheating temperature more than the glass transition temperature and softening temperature of dendritic polyester. The upper limit of the preheating temperature is preferably a temperature at which yarn path disturbance does not occur due to spontaneous elongation of the fiber during the preheating process. This preheating temperature setting at the time of drawing can contribute to the reduction of fiber diameter unevenness and the stability of physical properties in the longitudinal direction of the fiber.

  As mentioned above, because of the good fluidization effect due to the addition of the dendritic polyester, the kneader temperature can be lowered compared to the case where it is not added, but it is also possible to lower the set temperature for the spinning machine. Yes, higher viscosity polymers are more effective. For example, even if the spinning temperature usually has to be much higher than the melting point due to the high viscosity due to the high molecular weight polymer, if the dendritic polyester is added and the melting point of the thermoplastic polymer is + 10 ° C. or higher, spinning is no problem. Is possible. In general, in the case of high molecular weight PET, the melting point of PET is 260 ° C, but considering that the spinning temperature capable of spinning is set at 295 ° C and the melting point + 35 ° C, the addition of dendritic polyester greatly increases It can be seen that the spinning temperature can be lowered. The effect of adding dendritic polyester is not only to lower the spinning temperature, but also due to the slip effect of dendritic polyester, such as melt fracture that occurs due to increased shear stress with the wall surface in the mouthpiece hole. The phenomenon is suppressed, and the discharge of the polymer from the spinneret hole can be stabilized and a good fiber can be obtained. As described above, the spinning temperature in the melt spinning method of the present invention can be spun as long as it is equal to or higher than the melting point of the thermoplastic polymer due to the effect of improving the fluidity by the dendritic polyester. The temperature is preferably + 10 ° C. or more, and if it is within this range, spinning can be performed without any problem even in the extension deformation after discharge. In Comparative Example 1, the thermoplastic polymer used was 1.59 dL / g, while the IV of the discharged polymer was 0.89 dL / g and the IV drop was 0.70 dL / g, which is very large. As shown in Example 2, when the spinning temperature was lowered by 30 ° C., the polymer IV to be discharged was 1.20 dL / g, and the IV drop in this case was 0.39 dL / g, which is compared with Comparative Example 1. It can be seen that the IV drop is suppressed by 55%. As described above, in the melt spinning method of the present invention, thermal decomposition is greatly suppressed, and when a high molecular weight polymer is applied, the high molecular weight is maintained and discharged without lowering the molecular weight due to thermal degradation.

  Also, in the present invention, due to the good fluidization effect due to the addition of the dendritic polyester, the shear stress is reduced at the same temperature compared to the case where it is not added, and the shear heat generation during kneading is reduced. In comparison, high molecular weight fibers can be obtained. This effect can be obtained by combining it with a lower kneading temperature as much as possible. As this effect, for example, thermal decomposition, thermal denaturation, hydrolysis and the like of the polymer can be suppressed, and the high molecular weight and easy processability inherent to the thermoplastic polymer can be easily utilized.

  Hereinafter, the present invention will be described in detail using examples. In addition, the measuring method in an Example used the following method.

A. Absolute molecular weight of dendritic polyester The absolute molecular weight of dendritic polyester is GPC-MALLS (gel permeation chromatograph (Shodex GPC-101) -light scattering detector) using pentafluorophenol which is a solvent in which dendritic polyester is soluble. The sample concentration was 0.04% and the measurement temperature was 23 ° C. by Wyatt DAWN HELEOS)).

B. Chemical composition ratio of dendritic polyester The chemical composition ratio of dendritic polyester is dissolved in a pentafluorophenol / deuterated chloroform (50/50) mixed solvent using a nuclear magnetic resonance apparatus (JNM-AL400 manufactured by JEOL). 1H-NMR measurement was performed at 40 ° C., and the chemical composition ratio of each component was calculated from the peak intensity ratio.

C. The melting point of the dendritic polyester The melting point (Tm) of the dendritic polyester is the endothermic peak temperature (Tm1) observed when the dendritic polyester is measured at room temperature to 20 ° C./min in differential calorimetry. After observation, endothermic peak temperature (Tm) observed when the temperature is kept at Tm1 + 20 ° C for 5 minutes, cooled to room temperature under a temperature drop condition of 20 ° C / min, and measured again under a temperature rise condition of 20 ° C / min. It was.

D. Measurement of molecular end carboxylic acid group amount of dendritic polyester The molecular end carboxylic acid group amount was measured by a neutralization titration method. Dendritic polyester (0.5 g) was dissolved in 10-mL o-chlorophenol while heating at 90 ° C., cooled, and then 4 mL chloroform was added. After adding a few drops of bromophenol blue-ethanol solution (0.2 wt%), a titration reagent (0.04M potassium hydroxide-methanol solution) was added dropwise using a burette and added until the neutralization point was reached. The terminal carboxylic acid amount of the dendritic polyester was calculated from the titration reagent amount.

E. Intrinsic viscosity (IV) of polyester (thermoplastic polymer and discharge polymer)
The intrinsic viscosity of the polyester was dissolved in o-chlorophenol and measured at 25 ° C. using an Ostwald viscometer.

F. Relative viscosity (ηr) of nylon (thermoplastic polymer and discharge polymer)
Nylon was dissolved in a 98% sulfuric acid aqueous solution and adjusted to a concentration of 0.01 g / mL, and then measured at 25 ° C. using an Ostwald viscometer.

G. Melting | fusing point of thermoplastic polymer Using DS Instruments 2920 Modulated DSC made from TA Instruments, the peak top temperature which shows melting | fusing of a polymer by 2nd run was made into melting | fusing point of a polymer. The temperature rising rate at this time was 16 ° C./min, and the sample amount was 10 mg.

H. The single-filament fineness fiber of the fiber was reduced to 100 m by a measuring machine, and the weight was multiplied by 100 to obtain the total fineness. The single yarn fineness was calculated by dividing the total fineness by the number of filaments.

I. Mechanical properties of fibers (strength, elongation, toughness)
At room temperature (25 ° C.), an initial sample length = 200 mm, a pulling speed = 200 mm / min, and a load-elongation curve was obtained under the conditions shown in JIS L1013. Next, the load value at break was divided by the initial fineness, which was used as the strength, and the elongation at break was divided by the initial sample length to obtain a strong elongation curve. Moreover, toughness was calculated from strength and elongation according to the following formula.
(Toughness) = (Strength) × √ (Elongation) (cN / dtex ·% ^1/2 ).

Reference Example 1 (Synthesis of Dendritic Polyester A-1)
In a 500 mL reaction vessel equipped with a stirring blade and a distillation tube, 66.3 g (0.48 mol) of p-hydroxybenzoic acid, 8.38 g (0.045 mol) of 4,4′-dihydroxybiphenyl, and terephthalic acid 7. 48 g (0.045 mol), 14.41 g (0.075 mol) of polyethylene terephthalate having an intrinsic viscosity of about 0.6 dl / g, 31.52 g (0.15 mol) of trimesic acid and acetic anhydride 62.48 g (1.00 equivalent of the total phenolic hydroxyl groups) was charged and reacted at 145 ° C. for 2 hours with stirring in a nitrogen gas atmosphere. Thereafter, the temperature was raised to 280 ° C., and the mixture was stirred for 3 hours. When 91% of acetic acid was distilled, the heating and stirring were stopped, and the contents were discharged into cold water.

  The obtained dendritic polyester was dried at 110 ° C. for 5 hours using a dryer and then pulverized using a blender, and the obtained dendritic polyester powder was used for 12 hours at 100 ° C. using a vacuum heat dryer. Heated to vacuum dry.

  70 g of dried dendritic polyester powder and 31.4 g (0.19 mol) of ethyl orthoacetate as a carboxylic acid-reactive monofunctional compound were charged into a 500 mL reaction vessel equipped with a stirring blade and heated to 200 ° C. . After stirring at 200 ° C. for 20 minutes, the contents were discharged into cold water.

  The obtained dendritic polyester (A-1) was subjected to nuclear magnetic resonance spectrum analysis. As a result, the content p of p-oxybenzoate units was 2.66 (53.2 mol%) with respect to the trimesic acid residue. 4,4′-dioxybiphenyl unit and ethylene oxide unit content q is 0.66 (13.2 mol%), terephthalate unit content r is 0.66 (13.2 mol%), p + q + r = 4 Met.

  The obtained dendritic polyester (A-1) had a melting point Tm of 172 ° C. and a number average molecular weight of 2100.

Moreover, the molecular terminal carboxylic acid group amount of the obtained dendritic polyester (A-1) was 0.23 × 10 ⁻⁶ equivalent / g.

Reference Example 2 (Synthesis of dendritic polyester A-2)
A dendritic polyester (A-2) was obtained in the same manner as in Reference Example 1 except that the carboxylic acid-reactive monofunctional compound was 20.9 g (0.13 mol) of ethyl orthoacetate. The evaluation results of the obtained dendritic polyester are shown in Table 1.

Reference Example 3 (Synthesis of dendritic polyester A-3)
A dendritic polyester (A-3) was obtained in the same manner as in Reference Example 1 except that the carboxylic acid-reactive monofunctional compound was 28.5 g (0.19 mol) of 2-phenyl-2-oxazoline. The evaluation results of the obtained dendritic polyester are shown in Table 1.

Reference Example 4 (Synthesis of dendritic polyester A-4)
A dendritic polyester (A-4) was obtained in the same manner as in Reference Example 1 except that the carboxylic acid-reactive monofunctional compound was 28.5 g (0.19 mol) of 2-octyl-2-oxazoline. The evaluation results of the obtained dendritic polyester are shown in Table 1.

Reference Example 5 (Synthesis of Dendritic Polyester A-5)
A dendritic polyester (A-5) was obtained in the same manner as in Reference Example 1 except that the carboxylic acid-reactive monofunctional compound was 34.4 g (0.19 mol) of benzoic acid glycidyl ester. The evaluation results of the obtained dendritic polyester are shown in Table 1.

Reference Example 6 (Synthesis of dendritic polyester A-6)
Dendritic polyester (A-6) was obtained in the same manner as in Reference Example 1 except that the carboxylic acid-reactive monofunctional compound was 43.0 g (0.19 mol) of neodecanoic acid glycidyl ester. The evaluation results of the obtained dendritic polyester are shown in Table 1.

Reference Example 7 (Synthesis of dendritic polyester B-1)
In a 500 mL reaction vessel equipped with a stirring blade and a distillation tube, 66.3 g (0.48 mol) of p-hydroxybenzoic acid, 8.38 g (0.045 mol) of 4,4′-dihydroxybiphenyl, and terephthalic acid 7. 48 g (0.045 mol), 14.41 g (0.075 mol) of polyethylene terephthalate having an intrinsic viscosity of about 0.6 dl / g, 31.52 g (0.15 mol) of trimesic acid and acetic anhydride 62.48 g (1.00 equivalent of the total phenolic hydroxyl groups) was charged and reacted at 145 ° C. for 2 hours with stirring in a nitrogen gas atmosphere. Thereafter, the temperature was raised to 280 ° C., and the mixture was stirred for 3 hours. When acetic acid of 91% of the theoretical distillation amount was distilled, heating and stirring were stopped, the contents were discharged into cold water, and the molecular ends were blocked. Dendritic polyester (B-1) was obtained. The evaluation results of the dendritic polyester B-1 are shown in Table 1.

Reference Example 8 (Synthesis of dendritic polyester B-2)
A dendritic polyester (B-2) with insufficient molecular terminal blocking was prepared in the same manner as in Reference Example 1 except that the carboxylic acid-reactive monofunctional compound was 7.85 g (0.05 mol) of ethyl orthoacetate. Obtained. The evaluation results of the dendritic polyester B-2 are shown in Table 1.

Examples 1-4, Comparative Examples 1-6
After drying the dendritic polyester A-1 synthesized in Reference Example 1 and a high molecular weight polyethylene terephthalate (PET melting point 260 ° C.) having an IV of 1.59 dL / g, they were weighed separately and independently biaxial kneader (15 mmφ, L / D = 15). At this time, the addition amount of the dendritic polyester was 1 wt%. The temperature of the biaxial extrusion kneader was 290 ° C., the screw rotation speed was 100 rpm, venting was performed on the discharge side of the biaxial extrusion kneader, and the bubbles were extinguished. The spinning temperature was 290 ° C., and after filtering through a metal nonwoven fabric with an absolute filtration diameter of 10 μm, the single-hole discharge rate was 2.0 g / min from a die with a round hole of 10 holes (φ = 0.6 mm L / D = 1.5). Then, oil was supplied after passing through a uniflow cooling air zone (chimney) and wound up by a roller having a speed of 600 m / min (Example 1). In addition, as a comparison, when no dendritic polyester is added (Comparative Example 1), the dendritic polyester B-1 (Comparative Example 3) in which the molecular terminal synthesized in Reference Example 7 is not blocked and the molecular terminal synthesized in Reference Example 8 are used. The case where the dendritic polyester B-2 (Comparative Example 4) in which the blockage of the resin was insufficient was added under the conditions shown in Table 2. For reference, in each case, in order to see the effect of the melt spinning method of the present invention, the kneader temperature and spinning temperature were changed stepwise as shown in Table 2, and the screw torque (extrusion load current value) was changed. In addition, the pack pressure change was examined, and the ejection polymer IV and the mechanical properties of the fiber were evaluated.

  As is clear from the comparison between Examples 1 and 2 and Comparative Example 1, the addition of the dendritic polyester causes a significant decrease in pack pressure, and the fluidity of the high molecular weight PET is improved. It was confirmed (Fig. 1). Further, when the discharged polymer IV is evaluated, it increases with a decrease in the kneading temperature and the spinning temperature, and a very high molecular weight PET fiber of 1.20 dL / g is obtained for Example 2 set at 280 ° C. (Figure 2) It can be seen that the effect of improving the flow IV is suitable for the mechanical properties of the fiber, and an undrawn yarn having improved toughness as the discharge polymer IV increases is obtained. In Comparative Example 2 in which the kneader temperature was lowered with no addition, the load current value exceeded the control value (13A), and even the extrusion of the molten polymer was not satisfactory. Further, in order to clarify the effect of the dendritic polyester, the case where the dendritic polyester A-1 was added as reference data and only the spinning temperature was changed to 310 ° C. was examined, and is shown in FIG. The pack pressure was greatly reduced at the same spinning temperature as in Comparative Example 1, and the high effect of the dendritic polyester according to claim 1 was found.

  In order to see the influence of the amount of carboxylic acid groups of the dendritic polyester, when comparing the results of Examples 1 and 2 and Comparative Examples 3 to 6, the addition of the dendritic polyester exhibited a good fluidity effect, and Comparative Example 1 and Although it is confirmed that the screw torque and the pack pressure are reduced in comparison, the thrust IV is slightly reduced with the amount of the carboxylic acid group, and the mechanical properties are reduced as compared with Examples 1 and 2. Thus, the need for controlling the terminal structure of the dendritic polyester in the melt spinning method in which the dendritic polyester is added has been found. The results are shown in Table 2, FIG. 1 and FIG.

Examples 3 and 4
It carried out according to Example 1 except that the addition amount of the dendritic polyester A-1 was 0.1 and 10 wt%.

  In Example 3 in which the addition amount was 0.1 wt%, the screw torque and the pack pressure were reduced in spite of the fact that the spinning temperature was lowered as compared with Comparative Example 1, and the good flowability of the dendritic polyester It can be seen that the effect is obtained. Further, it was found that in Example 4 in which the addition amount was 10 wt%, the pack pressure was greatly reduced, and the fiber could be collected without any problem in the spinnability. The results are shown in Table 3.

Examples 5-7
The dendritic polyester was A-2 synthesized in Reference Example 2, and the spinning was performed based on the spinning conditions shown in Table 3.

  It can be seen from Example 5 that even when the dendritic polyester is A-2, an effect of good fluidity by addition is obtained, and this effect is also obtained in Example 6 in which the addition amount is 0.1 wt%. It can be seen that Furthermore, in Example 7 where the kneading temperature and the spinning temperature were lowered, it was found that a high-molecular-weight PET fiber having a discharge polymer IV of 1.09 dL / g was obtained. The results are shown in Table 3.

Examples 8-11
Table 4 shows the dendritic polyester as A-3 synthesized in Reference Example 3, A-4 synthesized in Reference Example 4, A-5 synthesized in Reference Example 5, and A-6 synthesized in Reference Example 6. Spinning was performed under conditions.

  Even when the carboxylic acid-reactive monofunctional compound is oxazoline (Examples 8 and 9) or epoxides (Examples 10 and 11), there is no problem in spinnability, and good fluidity due to the addition of dendritic polyester. From the effect, it was found that the screw torque and the pack pressure were reduced as compared with Comparative Example 1. The results are shown in Table 4.

Example 12
Spinning was performed under the conditions shown in Table 5 using the dendritic polyester A-1 synthesized in Reference Example 1 with an IV of PET (melting point 260 ° C.) of 1.10 dL / g.

  Even when the molecular weight of PET is lowered, the spinning temperature can be lowered to 280 ° C. from the effect of good fluidity due to the addition of the dendritic polyester, and it is possible to spin without any problems even under this temperature condition. I understood it. The results are shown in Table 5.

Examples 13 and 14
Using dendritic polyester A-1 synthesized in Reference Example 1 and IV of 0.65 dL / g for clothing grade PET (melting point: 255 ° C.), the single-hole discharge rate was reduced as shown in Table 5, and spinning was performed. went.

  Even in Example 15 in which the intrinsic viscosity was lowered as compared with Example 1, the effect of addition of the dendritic polyester was noticeable, and when referring to normal PET spinning at 275 ° C., there was a problem even in spinning set to a low temperature. It was found that spinning was possible. In addition, the spinnability is generally deteriorated by lowering the single-hole discharge amount, but the effect of good fluidity due to the addition of the dendritic polyester and the forced cooling due to the decrease in the spinning temperature are stable even in spinning set to a low discharge amount. It was found that spinnability can be maintained. The results are shown in Table 5.

Examples 15-17, Comparative Examples 7-9
In order to see the effect when added to polyester other than PET, spinning was carried out under the conditions shown in Table 6 with a thermoplastic polymer of IV1.51 dL / g polytrimethylene terephthalate (3GT melting point 230 ° C.).

  Even when the thermoplastic polymer was 3GT, it was found that the effect of good fluidity by adding the dendritic polyester was developed, and the pack pressure was reduced as compared with Comparative Example 7. Further, it was found that as the spinning temperature was lowered, the discharge polymer IV increased and the mechanical properties were greatly improved. In Comparative Example 8 to which Dendritic Polyester B-1 was added and Comparative Example 9 to which Dendritic Polyester B-2 was added, although the pack pressure was reduced, the discharge polymer IV was reduced compared to Comparative Example 7. I found out.

  Further, in Comparative Example 7, since the spinning temperature is high, when looking at the die surface after spinning for 8 hours, the generation of decomposition gas causes 10 m out of 24 holes to have a white turbid decomposition product adhering to the vicinity of the discharge hole. On the other hand, in Examples 19 and 20, only a fine deposit was observed in 1 of 24 holes, and it was found that the melt spinning method of the present invention was excellent in the effect of suppressing the base stain. . The results are shown in Table 6.

Example 18 and Comparative Example 10
The thermoplastic polymer was polybutylene terephthalate (PBT melting point 225 ° C.) having an IV of 0.85 dL / g, and spinning was performed under the conditions shown in Table 6.

  Compared to Comparative Example 10, it was found that in Example 21, the pack pressure was almost the same even when the spinning temperature was lowered by 10 ° C., and the discharge polymer IV was improved. Further, it was confirmed that the mechanical properties of the fibers were improved with the increase of the discharged polymer IV. The results are shown in Table 6.

Examples 19 and 20, Comparative Examples 11 and 12
In order to confirm the effect on polymers other than polyester, the thermoplastic polymer was nylon 66 (N66 melting point 260 ° C.) of ηr3.5, and spinning was performed while changing the spinning temperature and spinning speed as shown in Table 8. The winding atmosphere was 25 ° C. and 60% RH.

Comparing the addition and non-addition of dendritic polyester with respect to the pack pressure (Example 19 and Comparative Example 11), even if the spinning temperature is lowered by 15 ° C., the pack pressure value is almost the same, and the spinning temperature is reduced. I found it possible. The results are shown in Table 7. Further, in Comparative Example 11 in which no dendritic polyester was added, although the spinning speed was 600 m / min and a low spinning speed, the winding package was swollen due to the effect of longitudinal swelling, and it was difficult to wind up for 5 minutes or more. On the other hand, about Example 19 which added dendritic polyester, winding up for 30 minutes or more was possible, without collapsing a winding package. With respect to Comparative Example 12 in which the spinning speed was increased, the winding after 3 minutes could not be performed, and the package after the winding was greatly collapsed. On the other hand, about Example 20 which added dendritic polyester, winding up for 30 minutes or more was possible. For reference, under the spinning conditions of Examples 19 and 20 and Comparative Examples 11 and 12, sampling was stopped after 15 seconds, and the yarn was measured and collected immediately after measuring 2 m, and the atmosphere was 25 ° C. and 60% RH. Left under for 30 minutes. The sample length at the time of standing for 30 minutes was measured, and the longitudinal swelling ratio was calculated from the sample length before and after the standing based on the following formula. N66 fibers without addition of dendritic polyester had a longitudinal swelling rate of 6.2% at a spinning speed of 600 m / min (Comparative Example 11) and a longitudinal swelling rate of 9.1% at a spinning speed of 1500 m / min (Comparative Example 12), respectively. In contrast, N66 fiber to which dendritic polyester was added had a longitudinal swelling ratio of 0.9% at a spinning speed of 600 m / min (Example 19), and a longitudinal swelling ratio of 1 at a spinning speed of 1500 m / min (Example 20). It was found to be significantly suppressed to 0.0%.
<Vertical swelling rate>

Example 21, Comparative Example 13
The thermoplastic polymer was N66 (melting point 260 ° C.) of ηr2.6, and spinning was performed while changing the spinning temperature as shown in Table 8. The winding atmosphere was 25 ° C. and 60% RH.

  Compared to Comparative Example 13 in which no dendritic polyester was added, the pack pressure was the same even when the spinning temperature was lowered by 15 ° C., and it was found that the spinning temperature could be lowered by the addition of the dendritic polyester. . In addition, when dendritic polyester is added as in Example 19, stable winding can be performed for 30 minutes or more, whereas for Comparative Example 13 in which no dendritic polyester is added, winding for 5 minutes or more cannot be performed. It was. In the method described in Example 19, when the longitudinal swelling rate was measured, with respect to Comparative Example 13 in which no dendritic polyester was added, the longitudinal swelling rate was greatly swollen at 12%, whereas the dendritic polyester was added. In Example 21, it was found that the longitudinal swelling ratio was greatly suppressed to 2.1%.

Example 22 and Comparative Example 14
The thermoplastic polymer was nylon 6 with ηr2.5 (N6 melting point 220 ° C.), and spinning was performed while changing the spinning temperature as shown in the conditions shown in Table 8. The winding atmosphere was 25 ° C. and 60% RH.

  In Example 22, compared with Comparative Example 14, even when the spinning temperature was lowered by 20 ° C., the pack pressure was the same, and even when added to N6, the effect was high, and it was found that the spinning temperature could be lowered. The results are shown in Table 8. Further, in Comparative Example 14, sampling for 5 minutes or more was difficult due to the influence of longitudinal swelling, whereas in Example 22 to which dendritic polyester was added, there was no change in the package and stable winding for 30 minutes or more. It was possible to take. Further, when the longitudinal swelling ratio was measured in the same manner as in Example 22, the dendritic polyester-free N6 fiber (Comparative Example 14) had a longitudinal swelling ratio of 11.5%, whereas the dendritic polyester was added. It was found that the longitudinal swelling rate was significantly suppressed to 2.5% in the N6 fiber (Example 22).

1: Hopper 2: Metering device 3: Extrusion kneader 4: Spinning head 5: Spinning pack 6: Spinneret 7: Yarn 8: Chimney 9: Converging oiling guide 10: First take-up roller 11: Second take-up roller 12: Winding yarn

Claims (5)

At least one structural unit selected from an aromatic oxycarbonyl unit (P), an aromatic and / or aliphatic dioxy unit (Q), and an aromatic dicarbonyl unit (R), and a trifunctional organic residue (B And the content of B is 7.5 to 50 mol% with respect to the total content of P, Q, R and B, and the terminal carboxylic acid group content is 1 × 10 ^−4. A dendritic polyester having an equivalent weight / g or less is blended with a thermoplastic polymer so as to have a content of 0.1 to 10 wt%, and then melt-spun at a spinning temperature of the melting point of the thermoplastic polymer + 30 ° C. or less. A melt spinning method.   The melt spinning method according to claim 1, wherein the dendritic polyester contains a carboxylic acid-reactive monofunctional compound residue.   The melt spinning method according to claim 2, wherein the carboxylic acid-reactive monofunctional compound is at least one compound selected from orthoester, oxazoline, and epoxide. The melt spinning method according to any one of claims 1 to 3, wherein, when melt spinning, a single hole discharge rate is 5.0 x ^10-3 to 5.0 g / min.   The melt spinning method according to any one of claims 1 to 4, wherein the thermoplastic polymer is polyester.

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