JP6046958B2 - Polyamide resin composition and molded article comprising the same - Google Patents

Description

  The present invention relates to a polyamide resin composition excellent in whiteness and reflectance.

  The demand for light emitting diodes (LEDs) as a new light source is rapidly expanding as lighting and display elements from the viewpoint of low power consumption and long life, and the size and power of LEDs are increasing. Since LEDs efficiently use light, a reflector that also serves as a housing is important. As a resin material used for a reflector, in addition to whiteness and reflectance, heat resistance that can withstand soldering when mounted on an electronic substrate is required. In particular, since reflow soldering is often performed in recent years, resin materials are required to have heat resistance that can withstand a reflow soldering temperature of 260 ° C.

  As such a resin material, liquid crystal polymer (LCP), polyphenylene sulfide (PPS), and semi-aromatic polyamide are used. However, although LCP is excellent in melt fluidity and precision molding processability, there are problems in terms of whiteness and durability, and PPS has problems in moldability and mechanical strength. Further, among the semi-aromatic polyamides, polyhexamethylene terephthalamide (PA6T) alone has a problem that its melting point is too high and many copolymerization components are introduced, so that the crystallinity is low. Therefore, the crystallization time in the mold at the time of molding was long and the molding cycle was long. Further, since PA6T has a high water absorption rate, there is a problem that blisters are generated in the reflow soldering process.

  Therefore, use of polynonamethylene terephthalamide (PA9T) -based resin among semi-aromatic polyamides has been studied. For example, Patent Document 1 discloses a resin composition using titanium oxide for PA9T. Moreover, the Example has disclosed the resin composition which made the said resin composition contain the reinforcing material, the light stabilizer, and the mold release agent further.

JP 2004-75994 A

  However, in the polyamide resin composition of Patent Document 1, 2-methyl-1,8-octanediamine is copolymerized in addition to 1,9-nonanediamine in the polyamide diamine component to be used. Therefore, the polyamide resin composition of Patent Document 1 has a problem that the crystallization time in the mold during molding is long and the molding cycle becomes long.

  This invention solves the said subject, and it aims at providing the polyamide resin composition excellent in the moldability in addition to the outstanding whiteness, reflectance, mechanical characteristics, and heat resistance.

The inventors of the present invention have arrived at the present invention as a result of intensive studies to solve the above problems.
That is, the gist of the present invention is as follows.
(1) 100 parts by mass of a polyamide composed of a dicarboxylic acid component and a diamine component, 10 to 80 parts by mass of a fibrous reinforcing material and 10 to 60 parts by mass of a white pigment, and 0.01 to 5 parts by mass of a phosphorus-based antioxidant A polyamide resin composition containing, wherein the main component of the dicarboxylic acid component is terephthalic acid, and the main component of the diamine component is 1,8-octanediamine, 1,10-decanediamine, and 1,12-dodecanediamine. is at least one from the selected group, I supercooling degree is 40 ° C. der less as measured by differential scanning calorimetry of the polyamide, phosphorus-based antioxidant is tetrakis (2,4-di -t- Butylphenyl) -4,4-biphenylylene diphosphite, bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, Bis (nonylphenyl) polyamide resin composition which is a pentaerythritol diphosphite.
(2) The polyamide resin composition according to (1), wherein the diamine component is 1,10-decanediamine.
(3) The polyamide resin composition as described in (1) or (2), wherein the triamine unit is 0.3 mol% or less relative to the diamine unit in the polyamide.
(4) The polyamide resin composition according to any one of (1) to (3), wherein the fibrous reinforcing material is glass fiber.
(5) The polyamide resin composition according to any one of (1) to (4), wherein the white pigment is titanium oxide.
(6) The polyamide resin composition according to any one of (1) to (5), further containing 40 parts by mass or less of a plate-like reinforcing material per 100 parts by mass of polyamide.
(7) The polyamide resin composition according to any one of (1) to (6), further comprising 0.1 to 5 parts by mass of an antioxidant per 100 parts by mass of the polyamide.
(8) The polyamide resin composition according to any one of (1) to ( 7 ), further comprising 0.1 to 5 parts by mass of a light stabilizer per 100 parts by mass of polyamide.
(9) A reflector formed by molding the polyamide resin composition according to any one of (1) to ( 8 ).

  According to the present invention, it is possible to provide a polyamide resin composition having a short molding cycle in addition to the excellent whiteness, reflectance, mechanical properties, and heat resistance of conventional semi-aromatic polyamides.

  Hereinafter, the present invention will be described in detail.

  The polyamide used in the present invention is composed of a dicarboxylic acid component and a diamine component. In the present invention, it is necessary to use a dicarboxylic acid component and a diamine component having a specific chemical structure from the viewpoint of high crystallinity.

  The dicarboxylic acid component needs to use terephthalic acid as the main component, and the diamine component was selected from the group of 1,8-octanediamine, 1,10-decanediamine and 1,12-dodecanediamine as the main component. It is necessary to use one or more diamines. Terephthalic acid has a high chemical structure symmetry among aromatic dicarboxylic acids, and 1,8-octanediamine, 1,10-decanediamine, and 1,12-dodecanediamine are linear aliphatic diamines, and have a chemical structure. Since the symmetry is high, a polyamide having high crystallinity can be obtained by using these monomers.

  The number of carbon atoms of the diamine as the main component of the diamine component needs to be an even number. In general, in polyamide, a so-called even-odd effect is developed, and a more stable crystal structure is obtained when the number of carbon atoms of the monomer unit of the diamine component used is an even number than when the number of carbon atoms is an odd number. This is because crystallinity is improved.

  The carbon number of the diamine as the main component of the diamine component needs to be 8, 10, 12. When the number of carbon atoms of the diamine is less than 8, it is not preferable because the obtained polyamide has a melting point exceeding 340 ° C. and exceeding the decomposition temperature of the amide bond. On the other hand, when the diamine has more than 12 carbon atoms, the polyamide obtained is insufficient in heat resistance, which is not preferable. Note that due to the even-odd effect, the polyamide having 9 or 11 carbon atoms in the diamine has lower crystallinity than the polyamide having 8 or 10 or 12 carbon atoms in the diamine.

  The polyamide used in the present invention includes a dicarboxylic acid component other than the terephthalic acid component as the main component and / or other diamine components of a type other than the linear aliphatic diamine component having 8, 10 or 12 carbon atoms. (Hereinafter may be abbreviated as “copolymerization component”) may be copolymerized. The copolymerization component is preferably 5 mol% or less with respect to the total number of moles of the raw material monomers, and more preferably substantially free of the copolymerization component. By setting the copolymerization component to 5 mol% or less, high crystallinity can be imparted.

  Other dicarboxylic acid components include aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, And aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and naphthalenedicarboxylic acid.

  Other diamine components include 1,2-ethanediamine, 1,3-propanediamine, 1,4-butanediamine, 1,5-pentanediamine, 2-methyl-1,5-pentanediamine, 1,6- Hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 2-methyl-1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1, Examples thereof include aliphatic diamines such as 12-dodecanediamine, alicyclic diamines such as 1,4-cyclohexanediamine, and aromatic diamines such as metaxylylenediamine and paraxylylenediamine. In addition, any of 1,8-octanediamine, 1,10-decanediamine, and 1,12-octanediamine listed above is an essential diamine component for the polyamide of the present invention. When any one of 1,8-octanediamine, 1,10-decanediamine, and 1,12-dodecanediamine is used as an essential diamine component, the other diamine components are used as copolymerization components. For example, when 1,8-octanediamine is used as an essential diamine component, 1,10-decanediamine and 1,12-dodecanediamine are used as copolymerization components.

  If necessary, the polyamide may be copolymerized with lactams such as caprolactam and laurolactam, and ω-aminocarboxylic acids such as aminocaproic acid and 11-aminoundecanoic acid.

  The weight average molecular weight of the polyamide is preferably 15000 to 50000, more preferably 20000 to 50000, and further preferably 26000 to 50000. By setting the weight average molecular weight of the polyamide to 15000 to 50000, the mechanical properties can be improved while maintaining the fluidity at the time of injection molding.

  The polyamide used in the present invention preferably has a sufficiently reduced amount of triamine. Polyamide tends to have a triamine structure as a by-product due to a condensation reaction between diamines during polymerization. When the amount of triamine is large, a crosslinked structure is formed in the molecular chain, and the crosslinked structure restricts the movement and arrangement of the molecular chain, so that the crystallinity is lowered. Further, when the amount of triamine is large, a large amount of gel is generated, so that it may be present as fish eyes or irregularities on the surface of the obtained molded body, which may cause a deterioration of the surface appearance. Therefore, the triamine unit contained in the polyamide is preferably 0.3 mol% or less of the diamine unit, more preferably 0.15 mol% or less, and further preferably 0.12 mol% or less. Preferably, it is 0.10 mol% or less. When the triamine structure in the polyamide exceeds 0.3 mol% of the diamine unit, the crystallinity may be lowered, the surface smoothness of the molded product obtained by the generation of gel may be impaired, and the color tone may be lowered. is there.

  In order to make the triamine unit 0.3 mol% or less of the diamine unit, when the salt is formed from the terephthalic acid component and the diamine component, the amount of water or organic solvent added is 100 parts by mass based on the total amount of raw material monomers. The amount is preferably 5 parts by mass or less, more preferably less than 0.5 parts by mass, and still more preferably not used at all.

  In general, in order to allow the heat polymerization reaction of polyamide to proceed uniformly, a method is used in which raw materials are mixed in the presence of water and heated to advance the dehydration reaction. However, in such a method, when the total amount of water and the organic solvent during polymerization exceeds 5 parts by mass with respect to 100 parts by mass of the raw material monomers, an increase in the degree of polymerization may be suppressed. is there. In that case, the residence time in the polymerization apparatus in a state where there are many amine ends becomes longer, and the amount of triamine by-produced by the condensation reaction between diamines increases. As a result, a part of the polyamide has a crosslinked structure, and gelation is promoted or the color tone is lowered. Gelation causes a decrease in the crystallinity of the polyamide and delays the crystallization rate. And in the semi-aromatic polyamide like this invention, the production | generation of a triamine is more remarkable than an aliphatic polyamide. Therefore, as in the present invention, in order to obtain a polyamide in which the triamine unit is 0.3 mol% or less of the diamine unit, the amount of water or an organic solvent added is 5 masses per 100 mass parts of the raw material monomers in total. Part or less, and it is more preferable that water is not substantially added.

  The polyamide used in the present invention has a high crystallization rate and high moldability. The crystallization speed in the present invention can be determined by using the degree of supercooling measured using a differential scanning calorimeter (DSC) as an index. In the present invention, the degree of supercooling of the polyamide to be used needs to be 40 ° C. or less, and preferably 35 ° C. or less. If the degree of supercooling of the polyamide used exceeds 40 ° C., the molding cycle may not be shortened, or it may be difficult to release from the mold, and the continuous productivity during molding may be reduced.

  The polyamide used in the present invention can be produced by a heat polymerization method or a solution polymerization method that has been conventionally known as a method for producing a polyamide. Of these, the heat polymerization method is preferably used because it is industrially advantageous.

  Examples of the heat polymerization method include a method comprising a step (i) of obtaining a reactant from a monomer and a step (ii) of polymerizing the reactant. In the present invention, in order to obtain a polyamide in which the triamine unit is 0.3 mol% or less of the diamine unit, the step of step (i) is performed under the condition that the water and solvent in the polymerization system are low, that is, dicarboxylic acid and diamine. It is preferable to carry out in the presence of water and / or an organic solvent in which the total amount of water and the organic solvent is 5 parts by mass or less with respect to 100 parts by mass in total.

  As the step (i), for example, the dicarboxylic acid powder is heated in advance to a temperature not lower than the melting point of the diamine and not higher than the melting point of the dicarboxylic acid, and at a temperature not lower than the melting point of the diamine and not higher than the melting point of the dicarboxylic acid. The method of adding diamine to the dicarboxylic acid powder without substantially containing water so as to keep the water content. Alternatively, as another method, a suspension of a molten diamine and solid terephthalic acid is stirred and mixed to obtain a mixed solution, and then at a temperature lower than the melting point of the finally produced polyamide, terephthalic acid and Examples thereof include a method of obtaining a mixture of a salt and a low polymer by performing a salt production by a reaction with a diamine and a production reaction of a low polymer by the polymerization of the salt. In this case, crushing may be performed while the reaction is performed, or crushing may be performed after the reaction is once taken out. As the step (i), the former method in which the shape of the reactant is easily controlled is preferable.

  As the step (ii), for example, the reaction product obtained in the step (i) is solid-phase polymerized at a temperature lower than the melting point of the finally produced polyamide to increase the molecular weight to a predetermined molecular weight to obtain a polyamide. A method is mentioned. The solid phase polymerization is preferably performed in a stream of inert gas such as nitrogen at a polymerization temperature of 180 to 270 ° C. and a reaction time of 0.5 to 10 hours.

  In the production of polyamide, a polymerization catalyst can be used to increase the efficiency of polymerization, and an end-capping agent can be used to adjust the degree of polymerization, suppress thermal decomposition and coloring.

  Examples of the polymerization catalyst include phosphoric acid, phosphorous acid, hypophosphorous acid or salts thereof, and the addition amount of the polymerization catalyst is usually 2 mol% or less based on the total mol of dicarboxylic acid and diamine. It is preferable.

  Examples of the end-capping agent include monocarboxylic acids such as acetic acid, lauric acid, and benzoic acid, and monoamines such as octylamine, cyclohexylamine, and aniline, and any one of these or a combination thereof can be used. The amount of the end-capping agent added is usually preferably 5 mol% or less with respect to the total of the dicarboxylic acid component and the diamine component.

  Examples of the fibrous reinforcing material used in the present invention include glass fiber, potassium titanate fiber, alumina fiber, silica fiber, zirconia fiber, silicon carbide fiber, ceramic fiber, wollastonite, sepiolite, and attapulgite. Among them, glass fiber, potassium titanate fiber, wollastonite, sepiolite, and attapulgite are preferable because they do not melt at the melting temperature of the polyamide to be used, and glass fiber is more preferable.

  When using glass fiber, it is preferable that it is surface-treated with a silane coupling agent. Further, the silane coupling agent may be dispersed in the sizing agent and surface-treated as a sizing agent for bundling glass fibers. Examples of the silane coupling agent include vinyl silanes, acryl silanes, epoxy silanes, and amino silanes, but amino silanes are preferred because it is easy to obtain an adhesion effect between polyamide and glass fibers.

  The fiber length of the fibrous reinforcing material is preferably 0.1 to 7 mm, and more preferably 0.5 to 6 mm. The fiber diameter is preferably 3 to 20 μm, more preferably 5 to 13 μm. By setting the fiber length to 0.1 to 7 mm and the fiber diameter to 3 to 20 μm, it can be efficiently reinforced without adversely affecting the moldability. The cross-sectional shape of the fibrous reinforcing material is preferably a flat cross-section because the bending strength and the flexural modulus are improved.

  The content of the fibrous reinforcing material needs to be 10 to 80 parts by mass with respect to 100 parts by mass of the polyamide, preferably 15 to 60 parts by mass, and more preferably 20 to 50 parts by mass. When the content of the fibrous reinforcing material is less than 10 parts by mass, the improvement in mechanical strength is low, which is not preferable. On the other hand, when the content exceeds 80 parts by mass, not only the reinforcement efficiency of mechanical strength is lowered, but also workability at the time of melt kneading is lowered, and it becomes difficult to obtain a polyamide resin composition pellet, which is not preferable. .

  In the polyamide resin composition of the present invention, since the degree of supercooling of the polyamide is 40 ° C. or less, combined with the reinforcing effect of the molded body by the fibrous reinforcing material, the molded body at the time of taking out from the mold at the time of injection molding Increased rigidity. Therefore, the molded product can be taken out from the mold even if the cooling time is shortened as compared with the polyamide resin molded product not containing the fibrous reinforcing material. Therefore, the time required to form one molded body by injection molding (hereinafter abbreviated as “molding cycle”) can be shortened. This not only improves the production efficiency of the molded body, but also shortens the residence time of the resin that stays in the cylinder of the injection molding machine, especially when performing continuous injection molding. It is possible to suppress the generation of gas, suppress the deterioration product, decomposition gas, and mold contamination of the molded body, thereby improving the quality of the molded body. Suppression of mold contamination improves mold release at the time of taking out from the mold, and it can maintain good mold release performance continuously. Therefore, mold release failure when performing automatic molding on production lines etc. Continuous productivity capable of continuous molding for a long time can be improved without causing the operation to stop.

  The method of incorporating the fibrous reinforcing material is not particularly limited as long as the reinforcing effect is not impaired, but melt kneading using a biaxial kneader is preferably used. The kneading temperature must be equal to or higher than the melting point of the polyamide, and is preferably less than (melting point + 80 ° C.). If the kneading temperature is lower than the melting point, the kneader is overloaded, and problems such as vent-up may occur. If the kneading temperature is too high, the polyamide may be decomposed or yellowed.

  Examples of the white pigment used in the present invention include titanium oxide, zinc oxide, zinc sulfide, zinc sulfate, barium sulfate, calcium carbonate, and alumina. Among these, titanium oxide is preferable. By using titanium oxide as the white pigment, optical characteristics such as reflectance and concealment are improved. Titanium oxide is preferably a rutile type having a high refractive index and good light stability. The particle diameter of titanium oxide is preferably 0.05 to 2.0 μm, more preferably 0.05 to 0.5 μm. Titanium oxide may be surface-treated. Examples of the surface treatment agent include metal oxides such as alumina, silica, zinc oxide, and zirconium oxide, organic acids such as stearic acid, silane coupling agents, and titanium coupling agents. Two or more white pigments may be used in combination.

  The content of the white pigment is required to be 10 to 60 parts by mass with respect to 100 parts by mass of the polyamide, preferably 15 to 50 parts by mass, and more preferably 20 to 40 parts by mass.

  The polyamide resin composition of the present invention may further contain a plate-like reinforcing material. Examples of the plate-like reinforcing material include talc, mica, glass flake, kaolin, synthetic mica, montmorillonite, beidellite, nontronite, saponite, laponite, hectorite, sericite, dolomite, and swelling mica.

  The content of the plate-like reinforcing material is preferably 40 parts by mass or less with respect to 100 parts by mass of the polyamide. Dimensional stability can be improved by including a plate-like reinforcing material in the resin composition.

  An antioxidant may be further added to the polyamide resin composition of the present invention. Examples of the antioxidant include phosphorus antioxidants, hindered phenol antioxidants, hindered amine antioxidants, triazine compounds, and sulfur compounds. Among these, phosphorus antioxidants are preferable. When the polyamide resin composition containing a fibrous reinforcing material stays in a high-temperature cylinder for a long time, the surface treatment agent of the fibrous reinforcing material may be thermally decomposed to cause a decrease in mechanical strength. However, in the present invention, when the resin composition is accumulated for a long time in the cylinder, that is, when the molding cycle is long at the time of injection molding or even when the resin is retained in the cylinder for a long time with a small injection amount. By containing an inhibitor, a decrease in the tensile strength of the resin composition can be suppressed. The antioxidant is usually added for the purpose of decreasing the molecular weight of the polyamide or deteriorating the color. In the present invention, in addition to these effects, the residence stability of the resin composition can be improved. The addition amount of the antioxidant is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 5 parts by mass per 100 parts by mass of the polyamide.

  Among the antioxidants, it is particularly preferable to use a phosphorus-based antioxidant. The phosphorus-based antioxidant may be an inorganic compound or an organic compound, and is not particularly limited. For example, monosodium phosphate, disodium phosphate, trisodium phosphate, sodium phosphite, calcium phosphite, phosphorous acid Inorganic phosphates such as magnesium phosphate and manganese phosphite, triphenyl phosphite, trioctadecyl phosphite, tridecyl phosphite, trinonylphenyl phosphite, diphenylisodecyl phosphite, bis (2,6-di-tert) -Butyl-4-methylphenyl) pentaerythritol diphosphite (trade name “ADK STAB PEP-36”), tris (2,4-di-tert-butylphenyl) phosphite, distearyl pentaerythritol diphosphite (trade name) "ADK STAB PEP-8"), screw Nonylphenyl) pentaerythritol diphosphite (trade name “Adeka Stab PEP-4C”), tetrakis (2,4-di-t-butylphenyl) -4,4-biphenylylene phosphite (trade name “Hostanox P-EPQ” ]). Among these, bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite and tetrakis (2,4-di-t-butylphenyl) -4,4-biphenylylene diphosphite are preferable. These may be used alone or in combination.

  A light stabilizer may be further added to the polyamide resin composition of the present invention. In particular, when titanium oxide is used as the white pigment, it is preferable to add a light stabilizer because titanium oxide may promote photolysis. Examples of the light stabilizer include benzophenone compounds, benzotriazole compounds, salicylate compounds, hindered amine compounds, and hindered phenol compounds. Among these, hindered amine compounds are preferable.

  The addition amount of the light stabilizer is preferably 0.1 to 5 parts by mass, and more preferably 0.2 to 5 parts by mass with respect to 100 parts by mass of the polyamide. By setting the addition amount of the light stabilizer to 0.1 to 5 parts by mass per 100 parts by mass of the polyamide, it is possible to improve the light stability when used for applications such as a reflector.

  In the present invention, an antioxidant and a light stabilizer may be used in combination. By using the antioxidant and the light stabilizer in combination, it is possible to efficiently prevent light deterioration due to ultraviolet rays or the like during use while improving the retention stability during molding.

  In addition, you may add another additive to the polyamide resin composition of this invention as needed. Examples of other additives include fillers such as talc, swellable clay minerals, silica, alumina, and glass beads, antistatic agents, flame retardants, and flame retardant aids. The addition method of the white pigment, the plate-like reinforcing material, the heat stabilizer, the light stabilizer and other additives is not particularly limited as long as the effect is not impaired. For example, it is added at the time of polyamide polymerization or melt kneading. .

  Examples of the molding method of the polyamide resin composition of the present invention include an injection molding method, an extrusion molding method, and a blow molding method. Among them, the mechanical properties and moldability of the polyamide resin composition used in the present invention are sufficient. The injection molding method is preferable because it can be improved. Although it does not specifically limit as an injection molding machine, For example, a screw in-line type injection molding machine and a plunger type injection molding machine are mentioned. The polyamide resin composition heated and melted in the cylinder of the injection molding machine is weighed for each shot, injected into the mold in a molten state, cooled to a predetermined shape and solidified, and then as a molded body from the mold. It is taken out. The resin temperature at the time of injection molding must be equal to or higher than the melting point of the polyamide resin composition, and is preferably less than (melting point + 100 ° C.). When the polyamide resin composition is heated and melted, it is preferable to use a sufficiently dried polyamide resin composition. If the water content is large, the resin foams in the cylinder of the injection molding machine, and it may be difficult to obtain an optimal molded body. The moisture content of the polyamide resin composition used for injection molding is preferably less than 0.3% by mass, and more preferably less than 0.1% by mass.

  Since the polyamide resin composition of the present invention uses a polyamide having a degree of supercooling of 40 ° C. or less measured using a differential scanning calorimeter, the crystallization speed is high, and the molding cycle is particularly during processing of a molded body, particularly in injection molding. Is short. Therefore, not only the production efficiency of the molded body is improved, but also the residence time of the resin staying in the cylinder of the injection molding machine can be shortened particularly when continuously performing the injection molding. In addition, the deterioration of the resin and the generation of decomposition gas can be suppressed, and the deterioration product, decomposition gas can be prevented from entering the molded body, and mold contamination can be suppressed, thereby improving the quality of the molded body. Suppression of mold contamination is due to poor mold release when automatic molding is performed on the production line because the mold release at the time of taking out from the mold is good and good mold release performance can be maintained continuously. Continuous productivity that enables long-time continuous molding without causing shutdown can be improved.

  In addition, the polyamide used in the resin composition of the present invention has a higher melting point than polyamide 6 and polyamide 66, and a high melting temperature for obtaining a molded body. Therefore, when the resin stays in the molding machine cylinder for a long time, The resin is easily deteriorated and decomposition gas is easily generated. Therefore, shortening the molding cycle and suppressing the residence of the molten resin in the molding machine cylinder as much as possible is preferable for molding the polyamide resin composition of the present invention and obtaining a molded body having excellent heat resistance. is there.

  Moreover, since the polyamide resin composition of the invention has high crystallinity, it has higher whiteness and reflectance than conventional semi-aromatic polyamides. Therefore, when used for applications such as a reflector, the reflector made of the resin composition of the present invention can reflect light efficiently without substantially absorbing light.

  The polyamide resin composition of the present invention has high mechanical strength, heat resistance, and moldability, and is excellent in whiteness and reflectance. Therefore, it can be used in a wide range of applications such as automobile parts and electric / electronic parts. Examples of automobile parts include electrical components such as a lamp reflector, a lamp housing, a lamp extension, and a lamp socket. Examples of the electric / electronic component include an LED reflector and a display reflector.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

1. Measurement Method (1) Relative Viscosity of Polyamide Measured at a concentration of 1 g / dL and 25 ° C. using 96% by mass sulfuric acid as a solvent.

(2) Weight average molecular weight of polyamide After performing GPC analysis on a sample solution adjusted under the following conditions using a gel permeation chromatography apparatus manufactured by Tosoh Corporation, a calibration prepared using polymethyl methacrylate (manufactured by Polymer Laboratories) as a standard sample The weight average molecular weight was determined using a line.
<Sample preparation>
2 ml of hexafluoroisopropanol containing 10 mM sodium trifluoroacetate was added to 5 mg of polyamide and dissolved, followed by filtration with a disk filter.
<Conditions>
-Detector: Differential refractive index detector RI-8010 (manufactured by Tosoh Corporation)
・ Eluent: Hexafluoroisopropanol containing 10 mM sodium trifluoroacetate ・ Flow rate: 0.4 mL / min ・ Temperature: 40 ° C.

(3) Decreasing crystallization temperature, melting point, and degree of supercooling of polyamide Using a differential scanning calorimeter DSC-7 manufactured by PerkinElmer, Inc., the temperature was raised to 350 ° C. at a rate of temperature increase of 20 ° C./min. The temperature which gives the top of the exothermic peak when the temperature is lowered to 25 ° C. at a temperature lowering rate of 20 ° C./min is maintained at a temperature lowering crystallization temperature (Tcc). The top of the endothermic peak when the temperature was measured in minutes was taken as the melting point (Tm). The difference between the melting point and the cooling crystallization temperature (Tm-Tcc) was defined as the degree of supercooling. The smaller the degree of supercooling, the faster the crystallization.

(4) Amount of triamine in polyamide 3 mL of 47% hydrobromic acid was added to 10 mg of polyamide, heated at 130 ° C. for 20 hours, evaporated to dryness, and further dried under reduced pressure at 80 ° C. for 2 hours. To this, 2 mL of pyridine and 1 mL of N, O-bis (trimethylsilyl) trifluoroacetamide were added and heated at 90 ° C. for 30 minutes. After cooling, the solution filtered with a membrane filter was analyzed with a gas chromatography apparatus equipped with a mass spectrometer. Using a calibration curve obtained by separately measuring diamine and triamine as standard materials, diamine and triamine in the polyamide were quantified, and the molar ratio of triamine to diamine was calculated. As a triamine standard substance, a triamine compound obtained by reacting diamine with heating and stirring at 240 ° C. for 3 hours in an autoclave using palladium oxide as a catalyst was used.

(5) Melt flow rate (MFR)
Using the polyamide resin composition, measurement was performed at 340 ° C. and a load of 1.2 kgf in accordance with JIS K7210. Practically, 0.1 to 50 g / 10 min is preferable, and 1 to 40 g / 10 min is more preferable.

(6) Bending strength and flexural modulus After sufficiently drying the polyamide resin composition, injection molding is performed using an injection molding machine (EC100 manufactured by Toshiba Machine Co., Ltd.), and a molded piece of 127 mm × 12.7 mm × 3.2 mm Was made. The cylinder temperature (melting point + 25 ° C.), mold temperature (melting point-185 ° C.), injection pressure 100 MPa, injection time 10 seconds, and removal time 5 seconds.
Using the obtained molded piece, measurement was performed according to ASTM D790. In practice, the bending strength is preferably 100 MPa or more, and the flexural modulus is preferably 4 GPa or more.

(7) Whiteness In the same manner as in (6), a molded piece of 100 mm × 40 mm × 2 mm was produced. Using the obtained molded piece, brightness (L value), redness (a value), and yellowness (b value) according to Hunter's color difference formula were determined according to JIS Z8730, and whiteness was calculated according to the following formula.
W = 100 − [(100−L) ² + a ² + b ² ] ^1/2
Practically 90% or more is preferable.

(8) Reflectance Using the molded piece obtained in (7), the light reflectance at a wavelength of 470 nm was measured with a spectrophotometer SE6000 manufactured by Nippon Denshoku. In practice, the reflectance is preferably 85% or more, and more preferably 90% or more.

(9) Reflectance Retention Rate The molded piece of (8) was heated with a hot air dryer at 180 ° C. for 14 hours, and the light reflectivity retention rate before and after heating was calculated. The reflectance retention is preferably 70% or more, and more preferably 80% or more.

(10) Solder heat resistance After the molded piece obtained in (6) was left in an atmosphere of 40 ° C. and 95% RH (relative humidity) for 100 hours, it was heated in an infrared heating furnace at 150 ° C. for 1 minute. Next, the temperature was raised to 265 ° C. at a rate of 100 ° C./min and held for 10 seconds. The case where deformation or swelling did not occur in the molded piece was indicated as ◯, and the case where it occurred was indicated as x.

(10) Molding cycle When the molded body was molded in (6), the shortest time that could be easily taken out without deforming the molded body with the protruding pin was measured. Here, the molding cycle refers to the time from the start of the injection of the first shot of the molded body to the start of the injection of the second shot of the molded body when continuously molded under the same injection conditions. That is, it refers to the time required to mold one molded body (total of injection time + cooling time + removal time). Practically, it is preferably 30 seconds or less, and more preferably 25 seconds or less.

(11) Flow length Using a FANUC injection molding machine S2000i-100B, after setting the cylinder temperature at (melting point + 25 ° C.) ° C. and the mold temperature at (melting point−185 ° C.), the mold clamping force is 100 tons, injection Molding was performed by attaching a dedicated die with one-point gate on one side to the tip of the cylinder at a pressure of 100 MPa, an injection speed of 50 mm / second, and an injection time of 5 seconds. The dedicated mold has a shape in which an L-shaped molded product having a thickness of 0.4 mm and a width of 20 mm can be collected, and has a gate at the center of the spiral, and has a maximum flow length of 150 mm.
The longer the flow length, the better the fluidity.

(12) Stability of stability After setting at a cylinder temperature of 340 ° C. and a mold temperature of 130 ° C. using a FANUC injection molding machine S2000i-100B, a mold clamping force of 100 tons, an injection pressure of 100 MPa, and an injection speed of 50 mm / sec. A test piece (127 mm × 12.7 mm × 3.2 mm) was molded in a molding cycle of 20 seconds. About the obtained test piece, the tensile strength was measured based on ASTM D790. This tensile strength is referred to as “normal tensile strength”.
Further, the resin was retained in the cylinder of the injection molding machine for 10 minutes, and injection molding was performed in the same manner to obtain a test piece. The tensile strength of this test piece is defined as “tensile strength after residence”. Using the following formula, the tensile strength retention was determined and used as an indicator of retention stability.
Tensile strength retention rate (%) = Tensile strength after residence / Normal tensile strength x 100
Practically, the tensile strength retention is preferably 80% or more, more preferably 90% or more.

2. Raw material (1) Dicarboxylic acid component, terephthalic acid, isophthalic acid

(2) Diamine component, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,12-dodecanediamine

(3) Endblocker / benzoic acid

(4) Fibrous reinforcing material / GF-1: Glass fiber manufactured by Asahi Fiber Glass Co., Ltd., trade name “03JAFT692”, average fiber diameter 10 μm, average fiber length 3 mm
GF-2: Glass fiber manufactured by Nippon Electric Glass Co., Ltd., trade name “ECS03T-786H”, average fiber diameter 10.5 μm, average fiber length 3 mm
Flat GF: Nittobo flat glass fiber, trade name “CSG3PA820S”, major axis 28 μm × minor axis 7 μm, average fiber length 3 mm

(5) White pigment / titanium oxide A: manufactured by Ishihara Sangyo Co., Ltd., trade name “Taipeku CR-63”, average particle size 0.21 μm
-Titanium oxide B: manufactured by Ishihara Sangyo Co., Ltd., trade name “Taipeku CR-61”, average particle size 0.21 μm
-Titanium oxide C: manufactured by Ishihara Sangyo Co., Ltd., trade name “Taipeke PF-740”, average particle size 0.25 μm

(6) Antioxidant / IRG: hindered phenolic compound manufactured by BASF, trade name “Irganox 1098”
PA-1: Phosphorous antioxidant manufactured by Clariant Japan, Tetrakis (2,4-di-t-butylphenyl) -4,4-biphenylylene phosphite, trade name “Hostanox P-EPQ”
PA-2: Phosphoric antioxidant manufactured by Adeka Company, bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, trade name “ADK STAB PEP-36”
PA-3: Phosphoric antioxidant manufactured by Adeka Company, bis (nonylphenyl) pentaerythritol diphosphite, trade name “ADK STAB PEP-4C”
HPA: hindered phenol antioxidant manufactured by Ciba Specialty Chemicals, N, N′-hexane-1,6-diylbis [3- (3,5-di-tert-butyl-4-hydroxyphenylpropionamide], Product name "Irganox 1098"

(7) Light stabilizer / CHI: hindered amine compound manufactured by BASF, trade name “Chimassorb119FL”

Production Example 1
[Step (i)]
1,10-decanediamine (5050 parts by mass) as a diamine component, powdered terephthalic acid (4870 parts by mass) as a dicarboxylic component, benzoic acid (72 parts by mass) as a terminal blocking agent, sodium hypophosphite monohydrate as a polymerization catalyst The Japanese product (6 parts by mass) was placed in an autoclave and heated to 100 ° C., and then stirring was started at a rotation speed of 28 rpm using a double helical stirring blade, followed by heating for 1 hour. The molar ratio of the raw material monomers was 1,10-decanediamine: terephthalic acid = 50: 50. The mixture was heated to 230 ° C. while maintaining the rotation speed at 28 rpm, and subsequently heated at 230 ° C. for 3 hours. At that time, the formation reaction and crushing of the salt and the low polymer were carried out simultaneously. Thereafter, water vapor generated by the reaction was released to obtain a reaction product.

[Step (ii)]
The reaction product obtained in the step (i) was polymerized by heating at 230 ° C. for 5 hours in a dryer under a normal pressure nitrogen stream to obtain a polyamide (P-1).

Production Example 2
[Step (i)]
Terephthalic acid powder (4870 parts by mass) as a dicarboxylic component, sodium hypophosphite (6 parts by mass) as a polymerization catalyst, and benzoic acid (72 parts by mass) as a terminal blocking agent are placed in a ribbon blender reactor, and nitrogen is added. In a sealed state, the mixture was heated to 170 ° C. while stirring at a rotation speed of 30 rpm using a double helical stirring blade. Thereafter, decanediamine (5050 parts by mass) heated to 100 ° C. at a rate of 28 parts by mass at a rate of 28 parts by mass while maintaining the temperature at 170 ° C. and the number of revolutions at 30 rpm. The reaction product was obtained by adding continuously to the terephthalic acid powder over 3 hours (continuous liquid injection method). The molar ratio of the raw material monomers was 1,10-decanediamine: terephthalic acid = 50: 50.

[Step (ii)]
The reaction product obtained in step (i) was subsequently polymerized by heating to 230 ° C. under a nitrogen stream and heating at 230 ° C. for 5 hours in the ribbon blender reactor used in step (i). Polyamide (P-2) was obtained.

Production Examples 3 to 5 and 7
A polyamide was obtained in the same manner as in Production Example 2 except that the resin composition and production conditions were changed as shown in Table 1.

Production Example 6
[Step (i)]
1,10-decanediamine (5050 parts by mass) as a diamine component, powdered terephthalic acid (4870 parts by mass) as a dicarboxylic component, benzoic acid (72 parts by mass) as a terminal blocking agent, sodium hypophosphite monohydrate as a polymerization catalyst A Japanese product (6 parts by mass) and 400 parts by mass of distilled water (4 parts by mass with respect to 100 parts by mass of the total amount of raw material monomers) are placed in an autoclave, heated to 100 ° C., and then stirred at a rotational speed of 28 rpm. Heated for hours. The molar ratio of the raw material monomers was 1,10-decanediamine: terephthalic acid = 50: 50. The mixture was heated to 230 ° C. while maintaining the rotation speed at 28 rpm, and subsequently heated at 230 ° C. for 3 hours. At that time, the formation reaction and crushing of the salt and the low polymer were carried out simultaneously. Thereafter, water vapor generated by the reaction was released to obtain a reaction product.

[Step (ii)]
The reaction product obtained in the step (i) was polymerized by heating at 230 ° C. for 5 hours under a normal pressure nitrogen stream in a dryer to obtain a polyamide (P-6).

Production Example 8
[Step (i)]
1,10-decanediamine (5050 parts by mass) as a diamine component, powdered terephthalic acid (4870 parts by mass) with an average particle size of 80 μm as a dicarboxylic acid component, benzoic acid (72 parts by mass) as a terminal blocking agent, and the following as a polymerization catalyst Sodium phosphite monohydrate (6 parts by mass) and 9200 parts by mass of distilled water (92 parts by mass with respect to 100 parts by mass of the total amount of raw material monomers) were placed in an autoclave, heated to 100 ° C., and then rotated at 28 rpm. Stirring was started and heated for 1 hour. The molar ratio of the raw material monomers was 1,10-decanediamine: terephthalic acid = 50: 50. The mixture was heated to 230 ° C. while maintaining the rotation speed at 28 rpm, and subsequently heated at 230 ° C. for 3 hours. At that time, the formation reaction and crushing of the salt and the low polymer were carried out simultaneously. Thereafter, water vapor generated by the reaction was released to obtain a reaction product.

[Step (ii)]
The reaction product obtained in the step (i) was polymerized by heating at 230 ° C. for 5 hours in a dryer under a normal pressure nitrogen stream to obtain a polyamide (P-8).

Production Examples 8 and 9
A polyamide was obtained in the same manner as in Production Example 1 except that the content of the terminal blocking agent was changed.

  Table 1 shows the polyamide resin composition, production conditions, and characteristic values.

Reference example 1
100 parts by mass of polyamide (P-1) and 25 parts by mass of titanium oxide A were weighed using a loss-in-weight continuous quantitative supply device CE-W-1 manufactured by Kubota Corporation. The mixture was supplied to the main supply port of a shaft extruder (TEM37BS manufactured by Toshiba Machine Co., Ltd.), and 30 parts by mass of glass fiber (GF) was supplied from the side feeder to perform melt kneading. The temperature was 320 ° C. to 340 ° C., the screw rotation speed was 250 rpm, and the discharge amount was 35 kg / hour. Then, after taking up in strand form, it passed through the water tank, solidified by cooling, and it was cut with a pelletizer to obtain a polyamide resin composition.

Examples 1-5, Reference Examples 1-22 , Comparative Examples 1-3
As shown in Table 2, a polyamide resin composition was obtained in the same manner as in Reference Example 1 except that the resin composition was changed. Glass fiber was supplied from the side feeder, and the other was supplied from the main supply port.

Comparative Example 4
Although the same operation as in Reference Example 1 was performed, the strand was cut and the polyamide resin composition could not be obtained because the content of the fibrous reinforcing material was high.

Comparative Example 5
The same operation as in Reference Example 1 was performed, but since the content of the white pigment was high, the strands were cut and a polyamide resin composition could not be obtained.

Tables 2 and 3 show resin compositions and characteristic values of the polyamide resin compositions obtained in Examples , Comparative Examples, and Reference Examples .

Examples 1 to 5 and Reference Examples 1 to 22 had excellent bending strength and flexural modulus, high solder heat resistance, and excellent whiteness and reflectance. Further, since the degree of supercooling of the polyamide used was 40 ° C. or less, the molding cycle during injection molding was short.
Since Examples 1 to 5 used a phosphorus-based antioxidant, the retention stability was improved as compared with Example 1 that did not contain a phosphorus-based antioxidant.

In Comparative Example 1, since the diamine component of the polyamide used was not a monomer defined in the present invention, the whiteness and reflectance were low, and the molding cycle was long.
Since the comparative example 2 had little white pigment content, the whiteness and the reflectance were low.
In Comparative Example 3, since the content of the fibrous reinforcing material was small, the bending strength and the bending elastic modulus were low.

Claims (9)

A polyamide containing 100 parts by mass of a polyamide comprising a dicarboxylic acid component and a diamine component, 10 to 80 parts by mass of a fibrous reinforcing material and 10 to 60 parts by mass of a white pigment, and 0.01 to 5 parts by mass of a phosphorus-based antioxidant A resin composition, wherein the main component of the dicarboxylic acid component is terephthalic acid, and the main component of the diamine component is selected from the group consisting of 1,8-octanediamine, 1,10-decanediamine, and 1,12-dodecanediamine. is one or more members, it supercooling degree is 40 ° C. der less as measured by differential scanning calorimetry of the polyamide, phosphorus-based antioxidant is tetrakis (2,4-di -t- butyl-phenyl) -4,4-biphenylylene diphosphite, bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite or bis Nonylphenyl) polyamide resin composition which is a pentaerythritol diphosphite. The polyamide resin composition according to claim 1, wherein the diamine component is 1,10-decanediamine. The polyamide resin composition according to claim 1 or 2, wherein the triamine unit is 0.3 mol% or less based on the diamine unit in the polyamide. The polyamide resin composition according to any one of claims 1 to 3, wherein the fibrous reinforcing material is glass fiber. The polyamide resin composition according to claim 1, wherein the white pigment is titanium oxide. The polyamide resin composition according to any one of claims 1 to 5, further comprising 40 parts by mass or less of a plate-like reinforcing material per 100 parts by mass of polyamide. The polyamide resin composition according to any one of claims 1 to 6, further comprising 0.1 to 5 parts by mass of an antioxidant per 100 parts by mass of the polyamide. The polyamide resin composition according to any one of claims 1 to 7 , further comprising 0.1 to 5 parts by mass of a light stabilizer per 100 parts by mass of polyamide. Reflector obtained by molding a polyamide resin composition according to any one of claims 1-8.