JP6225693B2 - Polyamide resin composition - Google Patents

Description

  The present invention relates to a polyamide resin composition.

Polyamide resin is an engineering plastics with excellent mechanical strength such as impact resistance, friction resistance and wear resistance, heat resistance, and oil resistance. It is an automotive part, electronic / electric equipment part, OA equipment part, machine. Widely used in fields such as parts, building materials and housing related parts.
Polymetaxylylene adipamide resin (hereinafter also referred to as “MXD6”) obtained by the reaction of metaxylylenediamine and adipic acid has an aromatic ring in the main chain, has high rigidity, and is suitable for precision molding. It is positioned as an extremely excellent polyamide resin. Therefore, MXD6 has recently been used as a molding material in various fields such as automobile parts such as automobiles, general machine parts, precision machine parts, electronic / electric equipment parts, leisure sports equipment, civil engineering and building materials, especially injection molding materials. It has been widely used. However, high-rigidity polyamide resins such as MXD6 tend to have low toughness, and an increase in toughness may be desired depending on applications and processing methods.

As a method for improving various physical properties of a polyamide resin, a method is known in which a polyamide resin is reacted with a component capable of reacting with a terminal amino group or a terminal carboxyl group of the polyamide resin to modify the polyamide resin. For example, Patent Document 1 discloses a modification having excellent mechanical properties and surface properties obtained by mixing two kinds of polyamides having a specific repeating unit and a specific polyfunctional compound and reacting them in a molten phase. Polyamides are disclosed.
In addition to diamine and dicarboxylic acid as main component monomers constituting the polyamide resin, a method of modifying or modifying the polyamide resin by reacting or copolymerizing a small amount of a reactive compound is also known. For example, Patent Document 2 discloses fluidity and mechanical strength obtained by polymerizing a dicarboxylic acid monomer and a diamine monomer or a salt thereof in the presence of a polyfunctional compound capable of reacting with the monomer and a monofunctional compound. Polyamides that are superior to the above are disclosed.
Patent Document 3 discloses that a polyamide resin composition obtained by polycondensation of a diamine containing 70% by mole or more of metaxylylenediamine and a dicarboxylic acid and an alkali compound, and a terminal amino group after melt polymerization. It is disclosed that a polyvalent carboxylic acid may be further contained for the purpose of reducing the concentration.

  However, none of Patent Documents 1 to 3 mentions toughness improvement of polyamide resin. For example, according to the Example (Table 1) of Patent Document 2, it is shown that when the polyfunctional compound and the monofunctional compound are used, the tensile elongation of polyamide tends to decrease. Patent Documents 1 to 3 only disclose that other components are added for the purpose of reacting with a terminal component of the polyamide resin or a monomer component constituting the polyamide resin.

JP-T-2004-503633 Special table 2009-531506 gazette JP 2011-140621 A

  The present invention includes a polyamide resin having a structural unit derived from xylylenediamine as a diamine structural unit, and a polyamide resin composition capable of producing a molded article having particularly excellent toughness while maintaining the inherent tensile elastic modulus of the polyamide resin The issue is to provide goods.

The present inventors have found that the above-mentioned problems can be solved by using a polyamide resin composition containing a predetermined amount of a polyamide resin having a diamine structural unit derived from xylylenediamine and a specific polyvalent carboxylic acid compound. .
That is, the present invention provides the following [1] and [2].
[1] A polyamide resin (A) comprising a diamine structural unit containing 50 mol% or more of a structural unit derived from xylylenediamine and a dicarboxylic acid structural unit, and a polyamide resin composition containing trimesic acid, the polyamide resin (A) a polyamide resin composition having a trimesic acid content of 0.001 to 2 parts by mass with respect to 100 parts by mass;
[2] A molded article comprising the polyamide resin composition according to [1] above.

  According to the polyamide resin composition of the present invention, even when a polyamide resin having a structural unit derived from xylylenediamine as a diamine structural unit is used, excellent toughness is maintained while maintaining the inherent tensile elastic modulus of the polyamide resin. A molded body having the same can be produced. The polyamide resin composition of the present invention is a material for injection molding of automobile-related parts, OA equipment parts, electronic / electrical parts, mechanical parts, etc., various molding materials such as packaging films, hollow containers, pipes, tubes, hoses, and fibers. It is suitably used for materials and the like.

[Polyamide resin composition]
The polyamide resin composition of the present invention is a polyamide resin composition comprising a polyamide resin (A) composed of a diamine structural unit containing 50 mol% or more of a structural unit derived from xylylenediamine and a dicarboxylic acid structural unit, and trimesic acid. And content of trimesic acid with respect to 100 mass parts of said polyamide resins (A) is 0.001-2 mass parts, It is characterized by the above-mentioned. When such a polyamide resin composition of the present invention is used, a molded article having excellent toughness can be produced while maintaining the tensile elastic modulus inherent in the polyamide resin (A).
The reason why the above effect is obtained by the polyamide resin composition of the present invention is not clear, but it is presumed that a predetermined amount of trimesic acid acts like a plasticizer in the polyamide resin composition.
Here, in the polyamide resin composition of the present invention, in addition to the resin composition in which a predetermined amount of trimesic acid is added to the polyamide resin (A), a predetermined amount of trimesic acid is added to the polyamide resin (A), Also included are resin compositions obtained by melt-kneading. As will be described later, in the resin composition obtained by blending a predetermined amount of trimesic acid with the polyamide resin (A) and melt kneading, the terminal amino group of the polyamide resin (A) and the carboxyl group of trimesic acid are It has been found by the present inventors that there is substantially no reaction.

<Polyamide resin (A)>
The polyamide resin (A) is composed of a diamine structural unit containing 50 mol% or more of a structural unit derived from xylylenediamine and a dicarboxylic acid structural unit.

(Diamine structural unit)
The polyamide resin (A) used for this invention contains 50 mol% or more of structural units in which the diamine structural unit which comprises this polyamide resin (A) originates in xylylenediamine. As a result, the polyamide resin (A) is excellent in melt moldability, mechanical properties, and gas barrier properties. The content of the structural unit derived from xylylenediamine is preferably 70 mol% or more, more preferably 80 mol% or more, based on all diamine structural units, from the viewpoint of melt moldability, mechanical properties, and gas barrier properties. More preferably, it is 90 mol% or more.
The xylylenediamine is preferably metaxylylenediamine, paraxylylenediamine or a mixture thereof, and from the viewpoint of obtaining excellent toughness, it is a metaxylylenediamine or a mixture of metaxylylenediamine and paraxylylenediamine. More preferably, it is more preferably a mixture of metaxylylenediamine and paraxylylenediamine.
When xylylenediamine is a mixture of metaxylylenediamine and paraxylylenediamine, from the viewpoint of obtaining excellent toughness, the content of metaxylylenediamine in the mixture of metaxylylenediamine and paraxylylenediamine The amount is preferably 10 to 99 mol%, more preferably 40 to 95 mol%, still more preferably 60 to 90 mol%.

  The diamine structural unit may include a structural unit derived from a diamine other than xylylenediamine. Diamines other than xylylenediamine include tetramethylenediamine, pentamethylenediamine, 2-methylpentanediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, dodecamethylenediamine, 2,2 , 4-trimethyl-hexamethylenediamine, aliphatic diamines such as 2,4,4-trimethylhexamethylenediamine; 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, 1,3 -Diaminocyclohexane, 1,4-diaminocyclohexane, bis (4-aminocyclohexyl) methane, 2,2-bis (4-aminocyclohexyl) propane, bis (aminomethyl) decalin, bis (aminomethyl) tri Examples thereof include, but are not limited to, alicyclic diamines such as clodecane; diamines having an aromatic ring such as bis (4-aminophenyl) ether, paraphenylenediamine, and bis (aminomethyl) naphthalene; It is not a thing. The polyamide resin (A) can contain one or more structural units derived from these diamines.

(Dicarboxylic acid structural unit)
The dicarboxylic acid structural unit constituting the polyamide resin (A) used in the present invention is not particularly limited, but an aliphatic dicarboxylic acid having 4 to 20 carbon atoms from the viewpoint of molding processability, gas barrier properties, and mechanical properties, It is preferably a structural unit derived from at least one selected from terephthalic acid and isophthalic acid, more preferably a structural unit derived from an aliphatic dicarboxylic acid having 4 to 20 carbon atoms, and 4 to 12 carbon atoms. More preferred is a structural unit derived from an aliphatic dicarboxylic acid.
Examples of the aliphatic dicarboxylic acid having 4 to 20 carbon atoms include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,10-decanedicarboxylic acid, 1,11-undecanedicarboxylic acid, Examples include 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,16-hexadecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, and the like.
Among these, from the viewpoint of the crystallinity and high elasticity of the polyamide resin (A), a structural unit derived from at least one selected from adipic acid and sebacic acid is preferable, and a structural unit derived from sebacic acid is more preferable. The polyamide resin (A) can contain one or more of these dicarboxylic acid structural units.

  Other dicarboxylic acid constituent units are derived from aromatic dicarboxylic acids other than terephthalic acid and isophthalic acid, such as aliphatic dicarboxylic acids having 3 or less carbon atoms such as oxalic acid and malonic acid; 2,6-naphthalenedicarboxylic acid A structural unit is mentioned.

  The dicarboxylic acid structural unit preferably contains 50 mol% or more of a structural unit derived from an aliphatic dicarboxylic acid having 4 to 20 carbon atoms. The content of the constituent unit derived from the aliphatic dicarboxylic acid having 4 to 20 carbon atoms in the dicarboxylic acid constituent unit is more preferably 70 to 100 mol%, and further preferably 85 to 100 mol%. When the content is within the above range, the polyamide resin (A) has excellent toughness, moldability, gas barrier properties, and mechanical properties.

(Production of polyamide resin (A))
The polyamide resin (A) can be obtained by polycondensation of the diamine and dicarboxylic acid, which form the diamine structural unit and the dicarboxylic acid structural unit. The polycondensation reaction between the diamine and the dicarboxylic acid is not particularly limited, and any method such as a pressure method or an atmospheric pressure dropping method can be used. One example is a method of performing melt polycondensation (melt polymerization).
Specifically, a method comprising heating a salt comprising a diamine and a dicarboxylic acid in the presence of water at normal pressure or under pressure, and polycondensing in a molten state while removing added water and water produced by polycondensation. Is mentioned. Moreover, the method of adding diamine directly to molten dicarboxylic acid and performing polycondensation under a normal pressure or pressurization is also mentioned. In this case, in order to keep the reaction system in a uniform liquid state, diamine is continuously added to the dicarboxylic acid, and during that time, the reaction system is set so that the reaction temperature does not fall below the melting point of the generated oligoamide and polyamide resin (A). The polycondensation proceeds while the temperature rises.
Among the above, it is possible to reduce the molecular weight distribution of the polyamide resin (A) by using a melt polymerization method in which a diamine is dropped into a dicarboxylic acid melted at normal pressure or under pressure and polymerized in a molten state while removing condensed water. It is preferable because it is possible.

  The molar ratio of diamine to dicarboxylic acid (diamine / dicarboxylic acid) is preferably in the range of 0.9 to 1.1, more preferably in the range of 0.93 to 1.07, still more preferably 0.95 to 1. The range is 05, more preferably 0.97 to 1.02. If the molar ratio is within the above range, high molecular weight tends to proceed.

Moreover, you may add a phosphorus atom containing compound in a polycondensation reaction system for amidation reaction acceleration | stimulation and coloring suppression. Examples of the phosphorus atom-containing compound include phosphinic acid compounds such as dimethylphosphinic acid and phenylmethylphosphinic acid; hypophosphorous acid, sodium hypophosphite, potassium hypophosphite, lithium hypophosphite, magnesium hypophosphite, Diphosphite compounds such as calcium hypophosphite and ethyl hypophosphite; phosphonic acid, sodium phosphonate, potassium phosphonate, lithium phosphonate, potassium phosphonate, magnesium phosphonate, calcium phosphonate, phenylphosphonic acid, ethylphosphone Phosphonic acid compounds such as acid, sodium phenylphosphonate, potassium phenylphosphonate, lithium phenylphosphonate, diethyl phenylphosphonate, sodium ethylphosphonate, potassium ethylphosphonate; phosphonous acid, sodium phosphonite, phosphorous acid Lithium phosphonate, potassium phosphonite, magnesium phosphonite, calcium phosphonite, phenyl phosphonite, sodium phenyl phosphonite, potassium phenyl phosphonite, lithium phenyl phosphonite, ethyl phenyl phosphonite, etc. Phosphonic acid compounds; phosphorous acid, sodium hydrogen phosphite, sodium phosphite, lithium phosphite, potassium phosphite, magnesium phosphite, calcium phosphite, triethyl phosphite, triphenyl phosphite, pyro-subite Examples thereof include phosphorous acid compounds such as phosphoric acid.
Among these, metal hypophosphites such as sodium hypophosphite, potassium hypophosphite and lithium hypophosphite are particularly preferably used for promoting the amidation reaction, and sodium hypophosphite is particularly preferred. preferable. In addition, the phosphorus atom containing compound which can be used by this invention is not limited to these compounds.

  The addition amount of the phosphorus atom-containing compound added to the polycondensation reaction system is preferably 0.1 to 1,000 ppm, more preferably 1 to 600 ppm in terms of the phosphorus atom concentration in the polyamide resin (A). More preferably, it is 5-400 ppm.

Further, from the viewpoint of controlling the polycondensation reaction rate, an alkali metal compound may be allowed to coexist in the polycondensation reaction system.
As the alkali metal compound, alkali metal hydroxides and alkali metal acetates are usually used. However, the above phosphorus atom-containing compound containing an alkali metal is excluded. Specific examples of the alkali metal compound include, for example, lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, lithium acetate, sodium acetate, potassium acetate, rubidium acetate, cesium acetate, and the like. At least one selected from sodium hydroxide and sodium acetate is preferred. These can be used alone or in combination of two or more.
In addition, the said alkali metal compound may be added in a polycondensation reaction system, and may be derived from the dicarboxylic acid component which is a raw material of a polyamide resin (A).

The amount of the alkali metal compound used is preferably 0.05 to 1,000 ppm, more preferably 0.5 to 600 ppm, still more preferably 2.5 to 1,000 ppm in terms of alkali metal atom concentration in the polyamide resin (A). 400 ppm. The amount used is the total amount of the alkali metal compound added in the polycondensation system and the alkali metal compound derived from the dicarboxylic acid component which is the raw material of the polyamide resin (A).
The amount of the alkali metal compound used is an amount such that the value obtained by dividing the number of moles of the alkali metal compound by the number of moles of the aforementioned phosphorus atom-containing compound is usually in the range of 0.5 to 1.0, preferably The amount is in the range of 0.55 to 0.95, more preferably 0.6 to 0.9. Within the above range, the amidation reaction proceeds at an appropriate rate.
The phosphorus atom concentration and alkali metal atom concentration in the polyamide resin (A) can be measured by known methods such as ICP emission spectroscopic analysis, ICP mass spectrometry, and X-ray photoelectron spectroscopic analysis.

  The temperature of the polycondensation reaction is preferably 150 to 300 ° C, more preferably 160 to 280 ° C, and still more preferably 170 to 270 ° C. When the polymerization temperature is within the above range, the polymerization reaction proceeds rapidly. Moreover, since thermal decomposition of a monomer, an oligomer in the middle of polymerization, a polymer or the like hardly occurs, the properties of the obtained polyamide resin (A) are good.

  The time for the polycondensation reaction is usually 1 to 5 hours after the diamine component starts to be dropped. By setting the polycondensation reaction time within the above range, the molecular weight of the polyamide resin (A) can be sufficiently increased, and coloring of the resulting polyamide resin (A) can be suppressed.

The polyamide resin (A) obtained as described above is taken out from the polymerization tank, pelletized, and then dried and crystallized as necessary.
Further, in order to increase the degree of polymerization of the polyamide resin (A), solid phase polymerization may be further performed. Solid phase polymerization can be performed by a well-known method, for example, the method of heating at 100 degreeC or more and the temperature lower than melting | fusing point of a polyamide resin (A) for 1 to 24 hours in nitrogen atmosphere is mentioned.
As a heating device used in drying or solid phase polymerization, a continuous heating drying device, a tumble dryer, a conical dryer, a rotary drum type heating device called a rotary dryer, etc., and a rotary blade inside a nauta mixer However, the present invention is not limited thereto, and a known device can be used.

  The relative viscosity of the polyamide resin (A) is preferably in the range of 1.0 to 5.0, more preferably in the range of 1.5 to 4.0, from the viewpoints of moldability and mechanical properties. Specifically, the relative viscosity of the polyamide resin (A) can be measured by the method described in Examples.

  The number average molecular weight (Mn) of the polyamide resin (A) is preferably in the range of 10,000 to 50,000, more preferably 12,000 to 40,000, from the viewpoint of melt moldability and mechanical properties. In addition, the number average molecular weight of a polyamide resin (A) can be specifically measured by the method as described in an Example.

  The content of the polyamide resin (A) in the polyamide resin composition of the present invention is preferably more than 50% by mass, more preferably 70% by mass or more, and further preferably 90% by mass or more.

<Trimesic acid>
The polyamide resin composition of the present invention is characterized by containing a predetermined amount of trimesic acid. Trimesic acid is a polyvalent carboxylic acid compound represented by the following structural formula.

As described above, the polyamide resin composition of the present invention contains a predetermined amount of trimesic acid or the like in the polyamide resin (A), in addition to a resin composition in which a predetermined amount of trimesic acid is mixed in the polyamide resin (A). In addition, a resin composition obtained by melt kneading is also included. Even in the polyamide resin composition obtained by blending a predetermined amount of trimesic acid with the polyamide resin (A) and melt-kneading, the terminal amino group of the polyamide resin (A) and the carboxyl group of trimesic acid are substantially reacted. Not done. Therefore, it is speculated that a predetermined amount of trimesic acid acts like a plasticizer in the polyamide resin composition, and an effect of improving toughness is obtained.
A polyvalent carboxylic acid compound other than trimesic acid (for example, trimellitic anhydride, etc.) usually reacts with the terminal amino group of the polyamide resin when blended in the polyamide resin and melt kneaded. For this reason, it is considered that the effect of improving toughness like the polyamide resin composition of the present invention cannot be obtained. On the other hand, trimesic acid does not react with the terminal amino group of the polyamide resin (A) and is improved in toughness even if it is blended in the polyamide resin (A) and melt kneaded. The present inventors have found out.
The fact that the terminal amino group of the polyamide resin (A) and the carboxyl group of trimesic acid are not substantially reacted indicates that the terminal amino group concentration of the polyamide resin (A) and the amino group concentration in the polyamide resin composition are This can be confirmed by comparison. That is, if the amino group concentration in the polyamide resin composition is not lower than the terminal amino group concentration of the polyamide resin (A), the carboxyl group of trimesic acid has not reacted with the terminal amino group of the polyamide resin (A). Can be certified.
The terminal amino group concentration and terminal carboxyl group concentration of the polyamide resin (A), and the amino group concentration and carboxyl group concentration of the polyamide resin composition can be specifically measured by the methods described in Examples.

The polyamide resin composition of the present invention contains 0.001 to 2 parts by mass of trimesic acid with respect to 100 parts by mass of the polyamide resin (A). Thereby, the molded object which has the outstanding toughness can be produced, maintaining the tensile elasticity modulus which a polyamide resin (A) has originally. If the content of trimesic acid is less than 0.001 part by mass with respect to 100 parts by mass of the polyamide resin (A), the effect of improving toughness cannot be obtained. On the other hand, when the content of trimesic acid exceeds 2 parts by mass, the melt viscosity of the polyamide resin composition becomes too low, and the moldability tends to decrease and the coloring (YI value) tends to increase.
The content of trimesic acid in the polyamide resin composition is preferably 0.01 to 1.5 parts by mass with respect to 100 parts by mass of the polyamide resin (A) in terms of toughness improving effect, moldability, and coloring suppression. More preferably, it is 0.05-1.0 mass part, More preferably, it is 0.1-0.8 mass part.

  The polyamide resin composition of the present invention has a matting agent, a heat stabilizer, a weathering agent, an ultraviolet absorber, a nucleating agent, a plasticizer, a flame retardant, an antistatic agent, and an anti-coloring agent as long as the properties are not inhibited. Additives such as anti-gelling agents, clays such as layered silicates, inorganic fillers such as mica, talc, nanofillers, carbon fibers and glass fibers, organic fillers such as organic synthetic particles, organic synthetic fibers and natural fibers Can be contained.

[Production Method of Polyamide Resin Composition]
There is no restriction | limiting in particular in the manufacturing method of the polyamide resin composition of this invention. For example, a method of blending a polyamide resin (A) with a predetermined amount of trimesic acid and, if necessary, an additive and dry blending; the polyamide resin (A) is previously melt-kneaded, and a predetermined amount of trimesic acid is added thereto And a method of blending additives as necessary; and a method of melt-kneading after blending a predetermined amount of trimesic acid and various additives as necessary into the polyamide resin (A). From the viewpoint of uniformly mixing the polyamide resin (A) and trimesic acid, it is preferable to have a step of blending and melting and kneading a predetermined amount of trimesic acid to the polyamide resin (A). For example, a polyamide resin composition obtained by blending a polyamide resin (A) with a predetermined amount of trimesic acid and, if necessary, an additive, and melt-kneading can be used for molding as it is. Alternatively, the polyamide resin (A) may be blended with a predetermined amount of trimesic acid and, if necessary, an additive, melt-kneaded and then pelletized to produce a polyamide resin composition pellet, which may be subjected to a molding process. . Moreover, after producing the said pellet, solid-phase polymerization may be further performed and it may use for a shaping | molding process as it is.

Examples of the apparatus for melt kneading include various known extruders such as a batch kneader, a kneader, a kneader, a planetary extruder, a single screw or a twin screw extruder, among these, kneading ability, From the viewpoint of excellent productivity, a single screw extruder or a twin screw extruder is preferably used.
Trimesic acid can be added in solid form (powder) as long as it can be uniformly dispersed in the resin composition, and may be added in a solid form (powder) or dissolved in an arbitrary solvent such as an organic solvent. It may be added.
The temperature at the time of melt kneading is usually in the range of 190 to 310 ° C, and preferably 210 to 280 ° C from the viewpoint of preventing deterioration of the polyamide resin (A) and moldability.

From the viewpoint of moldability, the melt viscosity of the polyamide resin composition is preferably 200 to 1000 Pa · s, more preferably 250 to 800 Pa · s at a temperature of 250 ° C. and a shear rate of 121.6 s ⁻¹ . Further, at a temperature of 250 ° C. and a shear rate of 1216 s ^−1, it is preferably 100 to 750 Pa · s, more preferably 120 to 400 Pa · s. The melt viscosity can be specifically measured by the method described in the examples.

  According to the polyamide resin composition of the present invention, a molded product having excellent toughness and tensile elastic modulus can be produced. The said toughness can be evaluated by the tensile fracture strain measurement by the tensile test method based on JIS K7161 and K7162, and the Charpy impact test based on JIS K7111-1. Specifically, the evaluation of toughness and tensile modulus can be performed by the methods described in Examples.

[Molding]
The molded article of the present invention contains the polyamide resin composition of the present invention. The polyamide resin composition of the present invention may be used for at least a part of the molded product.
The molded article of the present invention can be produced, for example, by molding the aforementioned polyamide resin composition into various forms by a conventionally known molding method. Examples of the molding method include molding methods such as injection molding, blow molding, extrusion molding, compression molding, vacuum molding, press molding, direct blow molding, rotational molding, sandwich molding, and two-color molding.
When the injection molding method is used, the mold temperature is not particularly limited and can be appropriately selected depending on the type of the polyamide resin (A) to be used, the melt viscosity, and the like, but is preferably 30 ° C. or higher.
The molding temperature (resin temperature) at the time of injection molding can be appropriately selected depending on the type of polyamide resin (A) to be used, the melt viscosity, and the like, but is preferably 190 to 300 ° C, more preferably 200 to 260 ° C.
Further, an annealing step may be further performed after the injection molding. By performing the annealing process, the polyamide resin (A) can be stably crystallized even when the mold temperature during injection molding is less than 100 ° C., so that the physical properties of the resulting molded product are more stable. Will be.
Although there is no restriction | limiting in particular in annealing conditions, It is preferable to carry out at the temperature of 120-200 degreeC for 0.5 to 3 hours from a viewpoint of crystallizing a polyamide resin (A) stably and a viewpoint of manufacturing efficiency.

In the case of producing a film or sheet-like molded product, for example, an extrusion method equipped with a T die, an inflation film production method, or the like can be preferably used. Furthermore, a stretched film or a heat-shrinkable film can be obtained by stretching the obtained film or sheet. In addition, a multilayer structure having a film layer containing the polyamide resin composition of the present invention and a film layer made of another resin, for example, polyethylene, polypropylene, nylon, polyester resin, etc. using a method such as extrusion lamination or coextrusion. It can also be processed into a film.
Molded products containing the polyamide resin composition of the present invention include various molded products such as automobile-related parts, OA equipment parts, electronic / electrical parts, machine parts, injection molded products, packaging films, hollow containers, pipes, tubes, hoses, etc. It is suitable as a product, fiber or the like.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these. In this example, various measurements were performed by the following methods.

<Relative viscosity of polyamide resin (A)>
0.2 g of polyamide resin (A) was precisely weighed and dissolved in 20 mL of 96% sulfuric acid at 20-30 ° C. with stirring. After completely dissolving, 5 mL of the solution was quickly taken into a Cannon Fenceke viscometer and allowed to stand in a thermostatic bath at 25 ° C. for 10 minutes, and then the drop time (t) was measured. Further, the dropping time (t ₀ ) of 96% sulfuric acid itself was measured in the same manner. The relative viscosity was calculated from t and t _{0 according} to the following formula.
Relative viscosity = t / t ₀

<Amino group concentration and carboxyl group concentration>
The terminal amino group concentration and terminal carboxyl group concentration of the polyamide resin (A) were measured by the following methods.
(A) Terminal amino group concentration ([NH ₂ ] μeq / g)
0.5 g of the polyamide resin (A) was precisely weighed, and the polyamide was dissolved in 30 mL of a phenol / ethanol = 4/1 volume solution with stirring. After the polyamide resin was completely dissolved, it was determined by neutralization titration with N / 100 hydrochloric acid.
(B) Terminal carboxyl group concentration ([COOH] μeq / g)
0.5 g of the polyamide resin (A) was precisely weighed, and the polyamide resin was dissolved in 30 mL of benzyl alcohol with stirring at 160 to 180 ° C. in a nitrogen stream. After the polyamide resin was completely dissolved, it was cooled to 80 ° C. under a nitrogen stream, 10 mL of methanol was added with stirring, and neutralization titration with an N / 100 aqueous sodium hydroxide solution was performed.
The amino group concentration and the carboxyl group concentration in the polyamide resin composition were measured by the same method except that “polyamide resin (A)” was changed to “polyamide resin composition” in the above.

<Number average molecular weight (Mn) of polyamide resin and polyamide resin composition>
The number average molecular weights (Mn) of the polyamide resins obtained in the production examples and the polyamide resin compositions obtained in the examples and comparative examples were measured using gel permeation chromatography (GPC). The GPC measurement was performed using a GPC device “HLC-8320GPC EcoSEC” manufactured by Tosoh Corporation. Hexafluoroisopropanol (HFIP) was used as a solvent, and 1 mg of a sample was dissolved in 5 g of HFIP and used for measurement. The measurement conditions were “TSKgelSuperHM-H” manufactured by Tosoh Corporation as the measurement column, the column temperature was 40 ° C., and the solvent flow rate was 0.3 mL / min. The number average molecular weight (Mn) was calculated using polymethylmethacrylate (PMMA) as a standard sample and data processing software using “EcoSEC-WorkStation” manufactured by Tosoh Corporation.

<Melt viscosity>
The melt viscosity of the polyamide resin composition was measured using a capillary rheometer (“Capillograph 1C” manufactured by Toyo Seiki Co., Ltd. (capillary L / D = 10)), resin temperature 250 ° C., shear rate 121.6 s ⁻¹ , Measured at 1216 s ⁻¹ . In the measurement, the preheating time of the resin composition was 6 minutes.

<YI value>
The YI value of the polyamide resin composition was measured according to JIS K7373 using the polyamide resin composition pellets obtained in the examples and comparative examples. For the measurement, a color difference measuring device (manufactured by Nippon Denshoku Industries Co., Ltd., "Z-Σ80 Color Measuring System") was used.

<Tensile test (tensile modulus and tensile breaking strain)>
Using a tensile testing machine (“STROGRAPH APIII” manufactured by Toyo Seiki Seisakusho Co., Ltd.), a tensile test was performed in accordance with JIS K7161 and JIS K7162, and the tensile modulus and tensile breaking strain were measured. A test piece (1A type with a total length of 167 mm) was prepared by molding each polyamide resin composition using the molding method described in each example and comparative example, and the measurement temperature was 23 ° C., the humidity was 50% RH, and the gap between chucks. A tensile test was performed under the conditions of a distance of 115.0 mm and a tensile speed of 5 mm / min. The number of test pieces was five, and the average value of the results was calculated.

<Charpy impact strength>
The Charpy impact strength was measured according to JIS K7111-1. As a measuring apparatus, “UF IMPACT TESTER” manufactured by Ueshima Seisakusho Co., Ltd. was used. A test piece (80 mm × 10 mm × 4 mm) was prepared by molding each polyamide resin composition using the molding method described in each example and comparative example. Measurements were performed respectively. The number of test pieces was 10 and the average value of the results was calculated.

Production Example 1 (Production of polyamide resin (A1))
In a reaction vessel equipped with a stirrer, a partial condenser, a full condenser, a thermometer, a dropping funnel and a nitrogen introducing tube, and a strand die, 10 kg (49.4 mol) of sebacic acid (TA Grade manufactured by Ito Oil Co., Ltd.) and acetic acid After preparing 11.66 g of sodium / sodium hypophosphite monohydrate (molar ratio = 1 / 1.5) and sufficiently purging with nitrogen, the system was stirred while stirring the system under a small amount of nitrogen. It was heated and melted to 0 ° C.
6.680 kg of mixed xylylenediamine having a mass ratio of metaxylylenediamine (Mitsubishi Gas Chemical Co., Ltd.) and paraxylylenediamine (Mitsubishi Gas Chemical Co., Ltd.) of 70/30 (metaxylylenediamine 34. 33 mol, paraxylylenediamine (14.71 mol) was added dropwise to molten sebacic acid with stirring, and the internal temperature was continuously raised to 240 ° C. over 2.5 hours while discharging the condensed water produced out of the system. Warm up.
After completion of the dropwise addition, the internal temperature was raised, and when the temperature reached 250 ° C., the pressure in the reaction vessel was reduced, and the internal temperature was further raised to continue the melt polycondensation reaction at 255 ° C. for 20 minutes. Thereafter, the inside of the system was pressurized with nitrogen, and the obtained polymer was taken out of the strand die and pelletized to obtain a polyamide resin (A1). Said evaluation was performed about the obtained polyamide resin (A1).
Polyamide resin (A1) had a relative viscosity = 2.29, a terminal amino group concentration = 28 μeq / g, a terminal carboxyl group concentration = 100 μeq / g, and a number average molecular weight = 15668.

Production Example 2 (Production of polyamide resin (A2))
In Production Example 1, the same method as in Production Example 1 except that 6.680 kg of mixed xylylenediamine and paraxylylenediamine was changed to 6.680 kg (49.04 mol) of metaxylylenediamine. A polyamide resin (A2) was obtained.
The relative viscosity of the polyamide resin (A2) was 2.38, the terminal amino group concentration was 29 μeq / g, the terminal carboxyl group concentration was 83 μeq / g, and the number average molecular weight was 17021.

Example 1
To 9980 g of the polyamide resin (A1) obtained in Production Example 1, 20 g of trimesic acid was added and dry blended, and then at 260 ° C. using an extruder (Toshiba Machine Co., Ltd., model “TEM37BS”). The mixture was melt-kneaded and pelletized to obtain polyamide resin composition 1 pellets.
The pellets were injection molded under the following molding conditions A using an injection molding machine (manufactured by Sumitomo Heavy Industries, Ltd., model “SE130DU-HP”). Produced.
The said evaluation was performed using the said polyamide resin composition 1 and a molded object. The results are shown in Table 1.
<Molding condition A>
Mold temperature: 30 ° C
Injection molding temperature: 230 ° C
Annealing after injection molding; None

Example 2
In Example 1, a molded body was prepared in the same manner as in Example 1 except that the following molding condition B was used instead of the molding condition A, and the evaluation was performed. The results are shown in Table 1.
<Molding condition B>
Mold temperature: 30 ° C
Injection molding temperature: 230 ° C
Annealing after injection molding; 150 ° C for 1 hour in a hot air dryer

Example 3
To 9900 g of the polyamide resin (A1) obtained in Production Example 1, 100 g of trimesic acid was added and dry blended, and then at 260 ° C. using an extrusion molding machine (model “TEM37BS” manufactured by Toshiba Machine Co., Ltd.). The mixture was melt-kneaded and pelletized to obtain polyamide resin composition 2 pellets. Moreover, the molded object was produced by the method similar to Example 1 using the said pellet.
The said evaluation was performed using the said polyamide resin composition 2 and a molded object. The results are shown in Table 1.

Example 4
In Example 3, a molded body was produced in the same manner as in Example 3 except that the molding condition B was used instead of the molding condition A, and the evaluation was performed. The results are shown in Table 1.

Comparative Example 1
A molded body was produced in the same manner as in Example 2 except that trimesic acid was not used in Example 2, and the evaluation was performed. The results are shown in Table 1.

Comparative Example 2
In Example 2, except that trimellitic anhydride was used instead of trimesic acid, a comparative polyamide resin composition 1 and a molded product thereof were prepared and evaluated as described in Example 2. The results are shown in Table 1.

Example 5
In Example 1, the pellet of the polyamide resin composition 3 was obtained like Example 1 except having used the polyamide resin (A2) instead of the polyamide resin (A1). In addition, the pellets were injection molded under the following molding conditions C using an injection molding machine (manufactured by Sumitomo Heavy Industries, Ltd., model “SE130DU-HP”), and molded bodies of each shape used for the evaluation. Was made.
The said evaluation was performed using the said polyamide resin composition 3 and a molded object. The results are shown in Table 2.
<Molding condition C>
Mold temperature: 30 ° C
Injection molding temperature: 210 ° C
Annealing after injection molding; 150 ° C for 1 hour in a hot air dryer

Comparative Example 3
In Example 5, a molded body was produced in the same manner as in Example 5 except that trimesic acid was not used, and the evaluation was performed. The results are shown in Table 2.

From the results of Tables 1 and 2, the molded products using the polyamide resin compositions of Examples 1 to 5 are the tensile elastic modulus of the polyamide resin alone used in the composition (corresponding to Comparative Example 1 or Comparative Example 3). It can be seen that the toughness is improved while maintaining. Moreover, the amino group concentration of the polyamide resin compositions of Examples 1 to 5 obtained by melt-kneading is the terminal amino group concentration of the polyamide resin used in the composition (the amino group concentration of Comparative Example 1 or Comparative Example 3). Furthermore, the carboxyl group concentration of the composition increases with the amount of trimesic acid blended. This shows that the terminal amino group of the polyamide resin in the composition and the carboxyl group of trimesic acid are not substantially reacted.
On the other hand, the molded article using the polyamide resin composition of Comparative Example 2 containing a polyvalent carboxylic acid compound (trimellitic anhydride) other than trimesic acid has a smaller toughness-improving effect than the examples of the present application. I understand. Further, the amino group concentration of the polyamide resin composition of Comparative Example 2 is lower than the terminal amino group concentration of the polyamide resin used in the composition (amino group concentration of Comparative Example 1). From this, it is considered that the terminal amino group of the polyamide resin is reacted with the carboxyl group of the polyvalent carboxylic acid compound.

  According to the polyamide resin composition of the present invention, even when a polyamide resin having a structural unit derived from xylylenediamine as a diamine structural unit is used, excellent toughness is maintained while maintaining the inherent tensile elastic modulus of the polyamide resin. A molded body having the same can be produced. The polyamide resin composition of the present invention is a material for injection molding of automobile-related parts, OA equipment parts, electronic / electrical parts, mechanical parts, etc., various molding materials such as packaging films, hollow containers, pipes, tubes, hoses, and fibers. It is suitably used for materials and the like.

Claims (6)

  A polyamide resin (A) comprising a diamine structural unit containing 50 mol% or more of a structural unit derived from xylylenediamine and a dicarboxylic acid structural unit, and a polyamide resin composition containing trimesic acid, the polyamide resin (A) The polyamide resin composition whose content of trimesic acid with respect to 100 mass parts is 0.001-2 mass parts.   The polyamide resin composition according to claim 1, wherein the xylylenediamine is metaxylylenediamine or a mixture of metaxylylenediamine and paraxylylenediamine.   The polyamide resin composition according to claim 1 or 2, wherein the dicarboxylic acid structural unit contains 50 mol% or more of a structural unit derived from an aliphatic dicarboxylic acid having 4 to 20 carbon atoms.   The polyamide resin composition according to claim 3, wherein the structural unit derived from the aliphatic dicarboxylic acid is a structural unit derived from at least one selected from adipic acid and sebacic acid.   The polyamide resin composition according to any one of claims 1 to 4, wherein the polyamide resin composition is obtained by blending trimesic acid with the polyamide resin (A) and melt-kneading.   The molded article containing the polyamide resin composition in any one of Claims 1-5.