Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G69/00—Macromolecular compounds obtained by reactions forming a carboxylic amide link in the main chain of the macromolecule
  • C08G69/02—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids
  • C08G69/26—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids derived from polyamines and polycarboxylic acids
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/01—Use of inorganic substances as compounding ingredients characterized by their specific function
  • C08K3/013—Fillers, pigments or reinforcing additives
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/49—Phosphorus-containing compounds
  • C08K5/51—Phosphorus bound to oxygen
  • C08K5/53—Phosphorus bound to oxygen bound to oxygen and to carbon only
  • C08K5/5313—Phosphinic compounds, e.g. R2=P(:O)OR'
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L77/00—Compositions of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Compositions of derivatives of such polymers
  • C08L77/06—Polyamides derived from polyamines and polycarboxylic acids

Definitions

• the present invention relates to a polyamide resin composition and a molded article.
• polyamide resin compositions are easily flammable, for example, when they are used in automobile parts, they require flame retardancy.
• flame retardancy can be imparted to molded articles by adding a flame retardant to the polyamide resin composition.
• Patent Documents 1 to 7 disclose polyamide resin compositions containing an aromatic polyamide resin and a flame retardant. It is said that the polyamide resin compositions disclosed in Patent Documents 1 to 7 produce molded articles that exhibit good flame retardancy.
• these polyamide resin compositions contain a phosphorus-based flame retardant, such as a phosphinate compound, as the flame retardant.
• the object of the present invention is to provide a polyamide resin composition that can suppress a decrease in mechanical strength of a molded article having a thick portion when the molded article is produced, and can improve the flame retardancy of the molded article, and a molded article produced by molding the polyamide resin composition.
• one aspect of the present invention relates to a polyamide resin composition according to the following [1] to [6].
• a polyamide resin, and a phosphinate compound (C) whose content relative to 100 parts by mass of the polyamide resin is 10.0 parts by mass or more and 22.0 parts by mass or less
• the polyamide resin is A polyamide resin (A) including a component unit (Aa) derived from a dicarboxylic acid and a component unit (Ab) derived from a diamine;
• the polyamide resin (A) has a melting point of 280° C.
• the polyamide resin (B) has a heat of fusion ( ⁇ H) measured by a differential scanning calorimeter (DSC) of 0 J/g or more and 5 J/g or less,
• the content of the polyamide resin (B) relative to 100 parts by mass of the polyamide resin is 10.0 parts by mass or more and 40.0 parts by mass or less,
• the dicarboxylic acid-derived component unit (Aa) and the dicarboxylic acid-derived component unit (Ba) each contain a dicarboxylic acid-derived component unit which contains a dicarboxylic acid-derived component unit derived from terephthalic acid,
• the diamine-derived component unit (Ab) and the diamine-derived component unit (Bb) each contain a 1,6-diaminohexane-derived component unit.
• Polyamide resin composition [2] The polyamide resin composition according to [1], wherein the polyamide resin (A) has a melting point measured by a differential scanning calorimeter (DSC) of 320° C. or lower. [3] The polyamide resin composition further contains a reinforcing material (D) whose content is 30% by mass or more based on the total mass of the polyamide resin composition. The polyamide resin composition according to [1] or [2]. [4] The polyamide resin composition according to any one of [1] to [3], wherein the dicarboxylic acid-derived component unit (Ba) includes an isophthalic acid-derived component unit.
• DSC differential scanning calorimeter
• one aspect of the present invention relates to a molded article according to the following [7].
• [7] A molded article obtained by molding the polyamide resin composition according to any one of [1] to [6], The molded body has a thick portion having a thickness of 3.5 mm or more. Molded body.
• the present invention provides a polyamide resin composition that can suppress a decrease in mechanical strength of a molded article having a thick portion when molded and can improve the flame retardancy of the molded article, as well as a molded article obtained by molding the polyamide resin composition.
• the present invention is not limited to the following embodiments.
• the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages.
• the upper or lower limit value of that numerical range may be replaced with a value shown in the examples.
• the polyamide resin composition according to the present embodiment includes a polyamide resin and a phosphinate compound (C) whose content relative to 100 parts by mass of the polyamide resin is 10.0 parts by mass or more and 22.0 parts by mass or less.
• the polyamide resin includes a polyamide resin (A) containing a component unit (Aa) derived from a dicarboxylic acid and a component unit (Ab) derived from a diamine, and a polyamide resin (B) containing a component unit (Ba) derived from a dicarboxylic acid and a component unit (Bb) derived from a diamine.
• the polyamide resin (A) has a melting point of 280° C.
• the polyamide resin (B) has a heat of fusion ( ⁇ H) of 0 J/g or more and 5 J/g or less measured by a differential scanning calorimeter (DSC).
• the content of the polyamide resin (B) relative to 100 parts by mass of the polyamide resin is 10.0 parts by mass or more and 40.0 parts by mass or less.
• component unit (Aa) derived from the dicarboxylic acid and the component unit (Ba) derived from the dicarboxylic acid each contain a component unit derived from terephthalic acid
• component unit (Ab) derived from the diamine and the component unit (Bb) derived from the diamine each contain a component unit derived from 1,6-diaminohexane.
• the resin composition on the inside which hardens later, hardens with air bubbles, or cracks occur due to tensile stress.
• the polyamide resin composition contains a phosphinate compound, voids and cracks are particularly likely to occur near the interface between the polyamide resin and the phosphinate compound, and the thick part is likely to become brittle.
• the phosphinate compound is thermally decomposed by the shear heat generated when the components constituting the polyamide resin composition are kneaded, and by heating to melt the polyamide resin composition during molding.
• This thermal decomposition produces phosphoric acid, which decomposes the polyamide resin.
• the decomposition gas produced when the polyamide resin decomposes cannot escape from the thick sections of the molded body, making it easy for voids to form inside, and reducing the density of the thick sections.
• the content of the phosphinate compound is set to 22.0 parts by mass or less relative to the total mass of the polyamide resin, thereby reducing the amount of the interface between the polyamide resin and the phosphinate compound.
• polyamide resin (B) with low crystallinity is added to polyamide resin (A) that forms crystals in the molded product, so that the crystallinity of the polyamide resin can be appropriately reduced. This makes the polyamide resin less likely to shrink when cured, and therefore makes it difficult for the resin on the inner side of the thick portion to be pulled to the outer side when the polyamide resin composition is cooled and solidified.
• the amount of the phosphinate compound can also be reduced. Furthermore, since the polyamide resin composition contains polyamide resin (A) with a high molecular weight (specifically, an intrinsic viscosity [ ⁇ ] of 0.90 dl/g or more), the molecular weight of the polyamide resin can be maintained high even if the polyamide resin is decomposed by the phosphoric acid.
• the polyamide resin composition in this embodiment can increase the tensile strength of a molded article having a thick portion.
• the inventors' research also revealed that the flame retardancy of the molded article can be improved even if the content of the phosphinic acid salt compound (C) in the polyamide resin composition is lower than in the past.
• the polyamide resin composition of this embodiment is suitable for producing a molded article that includes a thick-walled portion having a certain thickness (e.g., 3.5 mm or more). Based on the above findings, the polyamide resin composition of this embodiment will be described below.
• Polyamide resin (A) The polyamide resin (A) is a polyamide resin having a melting point of 280° C. or higher as measured by a differential scanning calorimeter (DSC).
• the polyamide resin (A) forms crystals in a molded product, and can increase the mechanical strength (such as tensile strength) of the molded product. The method for measuring the melting point of the polyamide resin (A) will be described later.
• Polyamide resin (A) contains component units (Aa) derived from dicarboxylic acid and component units (Ab) derived from diamine.
• Component unit (Aa) derived from dicarboxylic acid The component units derived from dicarboxylic acids contained in the polyamide resin (A) include component units derived from terephthalic acid.
• the content of the component units derived from terephthalic acid is preferably 20 mol% or more and 100 mol% or less, more preferably 30 mol% or more and 90 mol% or less, even more preferably 40 mol% or more and 85 mol% or less, and even more preferably 40 mol% or more and 65 mol% or less, relative to the total number of moles of the component units (Aa) derived from dicarboxylic acids. If the content is 20 mol% or more, the concentration of aromatic rings in the polyamide resin (A) increases, making the polyamide resin more susceptible to carbonization. This makes it possible to further improve the flame retardancy of the molded body.
• the component unit (Aa) derived from a dicarboxylic acid may contain a component unit derived from another dicarboxylic acid other than the component unit derived from terephthalic acid.
• dicarboxylic acids include aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and aromatic dicarboxylic acids other than terephthalic acid. Of these, aliphatic dicarboxylic acids are preferred.
• aliphatic dicarboxylic acids examples include aliphatic dicarboxylic acids having 4 to 20 carbon atoms. The number of carbon atoms is preferably 6 to 12.
• examples of such aliphatic dicarboxylic acids include adipic acid, azelaic acid, and sebacic acid. Of these, adipic acid and sebacic acid are preferred.
• the content of the component units derived from the above aliphatic dicarboxylic acid is preferably 0 mol% or more and 60 mol% or less, and more preferably 0 mol% or more and 45 mol% or less, based on the total number of moles of the component units (Aa) derived from the dicarboxylic acid.
• alicyclic dicarboxylic acids examples include cyclohexanedicarboxylic acid and its esters.
• aromatic dicarboxylic acids other than terephthalic acid examples include isophthalic acid, 2-methylterephthalic acid, and naphthalenedicarboxylic acid.
• the content of component units derived from alicyclic dicarboxylic acids and aromatic dicarboxylic acids other than terephthalic acid is preferably 20 mol% or more and 80 mol% or less, and more preferably 25 mol% or more and 75 mol% or less, based on the total number of moles of component units (Aa) derived from dicarboxylic acids.
• Component unit (Ab) derived from diamine The diamine-derived component units contained in the polyamide resin (A) include 1,6-diaminohexane-derived component units.
• the content of the component units derived from 1,6-diaminohexane is preferably 30 mol% or more and 100 mol% or less, and more preferably 70 mol% or more and 100 mol% or less, based on the total number of moles of the component units (Ab) derived from diamine.
• the diamine-derived component unit (Ab) may contain component units derived from other diamines other than the component units derived from 1,6-diaminohexane.
• other diamines include aliphatic diamines having 4 to 15 carbon atoms other than 1,6-diaminohexane, component units derived from alicyclic diamines having 4 to 20 carbon atoms, and aromatic diamines.
• the number of carbon atoms in the aliphatic diamine is preferably 4 or more and 12 or less, and more preferably 6 or more and 12 or less.
• Examples of the aliphatic diamine include linear alkylene diamines and branched alkylene diamines.
• linear alkylenediamine examples include 1,4-diaminobutane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, and the like. Among these, 1,9-nonanediamine and 1,10-diaminodecane are preferred. Only one type of linear alkylenediamine may be included, or two or more types may be included.
• branched alkylene diamines examples include 2,2-dimethyldiaminopropane, 1,1-dimethyl-1,4-diaminobutane, 1-ethyl-1,4-diaminobutane, 1,2-dimethyl-1,4-diaminobutane, 1,3-dimethyl-1,4-diaminobutane, 1,4-dimethyl-1,4-diaminobutane, 2,3-dimethyl-1,4-diaminobutane, 2-methyl-1,5-diaminopentane, 2,5-dimethyl-1,6-diaminohexane, 2,4 -Dimethyl-1,6-diaminohexane, 3,3-dimethyl-1,6-diaminohexane, 2,2-dimethyl-1,6-diaminohexane, 2,2,4-trimethyl-1,6-diaminohexane, 2,2-
• Examples of alicyclic diamines having 4 to 20 carbon atoms include 1,4-diaminocyclohexane, 1,3-diaminocyclohexane, 1,3-bis(aminomethyl)cyclohexane, 2,5-bisaminomethylnorbornane, and 2,6-bisaminomethylnorbornane.
• Examples of aromatic diamines include metaxylylenediamine.
• the content of the component units derived from other diamines is preferably 0 mol% or more and 70 mol% or less, and more preferably 0 mol% or more and 30 mol% or less, relative to the total number of moles of the component units (Ab) derived from diamines.
• the constituent units of polyamide resin (A1) and their ratios can be calculated from the charge ratios used when preparing polyamide resin (A1) or can be measured by the NMR method.
• 1 H-NMR measurement for example, a nuclear magnetic resonance apparatus (ECX400 manufactured by JEOL Ltd.) is used, the solvent is deuterated orthodichlorobenzene, the sample concentration is 20 mg/0.6 mL, the measurement temperature is 120° C., the observation nucleus is 1 H (400 MHz), the sequence is a single pulse, the pulse width is 5.12 ⁇ sec (45° pulse), the repetition time is 7.0 sec, and the number of accumulations is 500 or more.
• ECX400 nuclear magnetic resonance apparatus manufactured by JEOL Ltd.
• the solvent is deuterated orthodichlorobenzene
• the sample concentration is 20 mg/0.6 mL
• the measurement temperature 120° C.
• the observation nucleus is 1 H (400 MHz)
• the sequence is a single pulse
• the pulse width is 5.12 ⁇ sec (45° pulse)
• the repetition time is 7.0 sec
• the number of accumulations is 500 or more.
• a nuclear magnetic resonance apparatus (ECP500 type manufactured by JEOL Ltd.) is used as the measurement apparatus, a mixed solvent of ortho-dichlorobenzene/heavy benzene (80/20% by volume) is used as the solvent, the measurement temperature is 120° C., the observation nucleus is 13 C (125 MHz), single pulse proton decoupling, 45° pulse, repetition time is 5.5 seconds, the number of accumulations is 10,000 or more, and the chemical shift reference value is 27.50 ppm. Assignment of various signals is performed based on a conventional method, and quantification can be performed based on the accumulated value of the signal intensity.
• polyamide resin (A) examples include polyamide 6T6I, polyamide 6T66, polyamide 6TDT, etc.
• the component units derived from dicarboxylic acid in polyamide resin (A) may include component units derived from biomass-derived dicarboxylic acid, and the component units derived from diamine may include component units derived from biomass-derived diamine.
• Polyamide resin (A) may also be a biomass-derived polyamide resin (A) obtained by polymerizing a group of raw materials including a biomass-derived raw material.
• the melting point of the polyamide resin (A) is preferably 280° C. or higher, more preferably 290° C. or higher, and even more preferably 300° C. or higher. From the viewpoint of suppressing corrosion of the molding machine, the melting point of the polyamide resin (A) is preferably 320° C. or lower. This allows the polyamide resin to be melted at a lower temperature during molding, making it difficult for the phosphinate compound to decompose thermally. This makes it difficult for the molding machine to be corroded by the thermally decomposed phosphinate compound (specifically, phosphoric acid generated by thermal decomposition).
• the melting point of polyamide resin (A) can be adjusted to the above range by adjusting the composition of polyamide resin (A).
• the melting point can be increased by increasing the content of the component unit derived from terephthalic acid, which will be described later.
• the polyamide resin (A) preferably has a glass transition temperature (Tg) measured by a differential scanning calorimeter (DSC) of 70°C or higher and 145°C or lower, more preferably 75°C or higher and 125°C or lower, and even more preferably 80°C or higher and 100°C or lower.
• Tg glass transition temperature
• DSC differential scanning calorimeter
• the heat of fusion ( ⁇ H) of polyamide resin (A) measured by differential scanning calorimetry (DSC) is preferably greater than 5 J/g.
• the heat of fusion is an index of the crystallinity of a resin, and a larger heat of fusion indicates higher crystallinity.
• the heat of fusion ( ⁇ H) of polyamide resin (A) exceeds 5 J/g, the crystallinity is increased, and the tensile strength of the resulting molded article can be increased.
• the melting point and heat of fusion ( ⁇ H) of polyamide resin (A) can be measured using a differential scanning calorimeter (DSC220C, manufactured by Seiko Instruments Inc.).
• polyamide resin (A) is sealed in an aluminum pan for measurement and heated from room temperature to 350°C at 10°C/min. In order to completely melt the resin, it is held at 350°C for 3 minutes and then cooled to 30°C at 10°C/min. After leaving it at 30°C for 5 minutes, it is heated a second time to 350°C at 10°C/min.
• the temperature (°C) of the endothermic peak in this second heating is taken as the melting point (Tm) of polyamide resin (A), and the transition point corresponding to the glass transition is taken as the glass transition temperature (Tg).
• Tm melting point
• Tg glass transition temperature
• the heat of fusion ( ⁇ H) is determined from the area of the endothermic peak during melting in the first heating process in accordance with JIS K7122.
• the intrinsic viscosity [ ⁇ ] of the polyamide resin (A) measured at 25°C in 96.5% sulfuric acid is 0.90 dl/g or more, preferably 0.90 dl/g to 1.20 dl/g or less, more preferably 1.00 dl/g to 1.20 dl/g or less, and particularly preferably 1.00 dl/g to 1.10 dl/g or less.
• the intrinsic viscosity [ ⁇ ] of the polyamide resin (A) is 1.00 dl/g or more, the mechanical strength (tensile strength, etc.) of a molded body having a thick wall portion is easily increased sufficiently, and when it is 1.20 dl/g or less, the fluidity of the resin composition during molding is not easily impaired.
• the intrinsic viscosity [ ⁇ ] can be adjusted by adjusting the molar ratio of the component unit (Aa) derived from the dicarboxylic acid and the component unit (Ab) derived from the diamine. Specifically, the closer the molar ratio of the component unit (Aa) derived from a carboxylic acid to the component unit (Ab) derived from a diamine is to 1:1, the higher the intrinsic viscosity can be. It can also be adjusted by the amount of terminal blocking of the polyamide resin (A).
• the intrinsic viscosity [ ⁇ ] of polyamide resin (A) can be measured as follows. 0.5 g of polyamide resin (A) is dissolved in 50 ml of 96.5% sulfuric acid solution to prepare a sample solution. The flow time of the obtained solution at 25°C ⁇ 0.05°C is measured using an Ubbelohde viscometer and calculated based on the following formula.
• Polyamide resin (A) can be produced in the same manner as known polyamide resins, for example, by polycondensing dicarboxylic acid and diamine in a homogeneous solution. Specifically, as described in WO 03/085029, dicarboxylic acid and diamine are heated in the presence of a catalyst to obtain a low-order condensate, and then a shear stress is applied to the melt of this low-order condensate to polycondense it.
• the content of polyamide resin (A) is preferably 25.00 mass% or more and 65.00 mass% or less, preferably 30.00 mass% or more and 60.00 mass% or less, and more preferably 35.00 mass% or more and 55.00 mass% or less, based on the total mass of the polyamide resin composition.
• the content is 25.00 mass% or more, the tensile strength of the polyamide resin composition can be further increased.
• the content is 65.00 mass% or less, other components such as polyamide resin (B) and phosphinic acid salt compound (C) described below can be included in the polyamide resin composition, and the tensile strength and flame retardancy of a molded article having a thick portion can be further increased.
• Polyamide resin (B) The polyamide resin (B) has a heat of fusion ( ⁇ H) of 0 J/g or more and 5 J/g or less as measured by a differential scanning calorimeter (DSC).
• ⁇ H heat of fusion
• the heat of fusion is an index of the crystallinity of a resin, and the smaller the heat of fusion, the lower the crystallinity. Therefore, the heat of fusion of polyamide resin (B) is preferably 0 J/g. Also, polyamide resin (B) is preferably an amorphous resin whose melting point is not substantially measured by a differential scanning calorimeter (DSC). In this specification, "the melting point is not substantially measured” means that in the aforementioned melting point measurement using a differential scanning calorimeter (DSC), an endothermic peak due to crystalline melting is not substantially observed during the second heating.
• DSC differential scanning calorimeter
• the heat of fusion ( ⁇ H) of the polyamide resin (B) can be adjusted to the above range by adjusting the composition of the polyamide resin (B).
• the heat of fusion can be reduced by increasing the content of the component unit derived from isophthalic acid, which will be described later.
• Polyamide resin (B) contains a component unit (Ba) derived from a dicarboxylic acid and a component unit (Bb) derived from a diamine.
• Component unit (Ba) derived from dicarboxylic acid includes component units derived from terephthalic acid.
• the content of the component units derived from terephthalic acid is preferably 0 mol% or more and 50 mol% or less, and more preferably 15 mol% or more and 45 mol% or less, relative to the total number of moles of the component units (Ba) derived from dicarboxylic acids.
• the component unit (Ba) derived from a dicarboxylic acid preferably contains a component unit derived from isophthalic acid. This increases the concentration of aromatic rings in the polyamide resin (B), making the polyamide resin more susceptible to carbonization. This can further increase the flame retardancy of the molded body.
• the component units derived from isophthalic acid preferably account for 50 mol% or more and 100 mol% or less, and more preferably 55 mol% or more and 85 mol% or less, of the total number of moles of the component units (Ba) derived from dicarboxylic acids. If the content of isophthalic acid component units is 50 mol% or more, the crystallinity of the polyamide resin (B) can be further reduced.
• the molar ratio to the component units derived from terephthalic acid is preferably 55/45 to 95/5, more preferably 60/40 to 80/20, and even more preferably 60/40 to 70/30.
• the crystallinity of the polyamide resin (B) can be further reduced. This can reduce the crystallinity of the polyamide resin and reduce the difference in hardening speed between the outer side and the inner side of the thick-walled portion of the molded body. As a result, the occurrence of voids and cracks in the thick-walled portion can be further suppressed, and the tensile strength can be further increased.
• Component unit (Bb) derived from diamine includes a component unit derived from 1,6-diaminohexane.
• the content of the component units derived from 1,6-diaminohexane is preferably 30 mol% or more and 100 mol% or less, and more preferably 70 mol% or more and 100 mol% or less, based on the total number of moles of the component units (Bb) derived from diamine.
• the diamine-derived component units (Bb) may contain component units derived from other diamines other than the component units derived from 1,6-diaminohexane.
• examples of other diamines include aliphatic diamines having 4 to 15 carbon atoms other than 1,6-diaminohexane, component units derived from alicyclic diamines having 4 to 20 carbon atoms, and aromatic diamines.
• the types of these can be the same as those described for polyamide resin (A).
• the content of the component units derived from other diamines can be, for example, 0 mol % to 10 mol % based on the total number of moles of the diamine-derived component units (Bb).
• the constituent units of polyamide resin (B) and their ratios can be calculated from the charge ratios used when preparing polyamide resin (B) or can be measured by the NMR method.
• the NMR method can be the same as that described for polyamide resin (A).
• polyamide resin (B) examples include polyamide 6I6T.
• the intrinsic viscosity [ ⁇ ] of polyamide resin (B) measured in 96.5% sulfuric acid at 25°C is preferably 0.60 dl/g or more and 1.60 dl/g or less, more preferably 0.60 dl/g or more and 1.20 dl/g or less.
• the intrinsic viscosity of polyamide resin (B) can be measured in the same manner as the intrinsic viscosity of polyamide resin (A).
• Polyamide resin (B) can be produced in the same manner as described for polyamide resin (A).
• the content of polyamide resin (B) is 10.0 parts by mass or more and 40.0 parts by mass or less, and preferably 15.0 parts by mass or more and 30.0 parts by mass or less, relative to 100 parts by mass of the total mass of the polyamide resin.
• the content is 10.0 parts by mass or more, the occurrence of voids and cracks in the thick-walled portion during molding can be suppressed. This makes it possible to increase the tensile strength in the thick-walled portion.
• the content is 40.0 parts by mass or less, the content of polyamide resin (A) in the polyamide resin can be relatively increased, thereby increasing the tensile strength of the molded body.
• the component units derived from dicarboxylic acid of polyamide resin (B) may include component units derived from biomass-derived dicarboxylic acid, and the component units derived from diamine may include component units derived from biomass-derived diamine.
• Polyamide resin (B) may also be a biomass-derived polyamide resin (B) obtained by polymerizing a raw material group including a biomass-derived raw material.
• the polyamide resin composition contains a phosphinate compound (C) which is a flame retardant.
• phosphinate compounds are, for example, compounds represented by the following formulas (I) and (II).
• R 1 and R 2 are each independently a linear or branched alkyl group or aryl group having 1 to 6 carbon atoms.
• R 3 is a linear or branched alkylene group having 1 to 10 carbon atoms, an arylene group having 6 to 10 carbon atoms, an alkylarylene group having 6 to 10 carbon atoms, or an arylalkylene group having 6 to 10 carbon atoms.
• M is Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, K, and/or a protonated nitrogen base.
• m, n, and x are each independently an integer of 1 to 4.
• phosphinate compounds include calcium dimethylphosphinate, magnesium dimethylphosphinate, aluminum dimethylphosphinate, zinc dimethylphosphinate, calcium ethylmethylphosphinate, magnesium ethylmethylphosphinate, aluminum ethylmethylphosphinate, zinc ethylmethylphosphinate, calcium diethylphosphinate, magnesium diethylphosphinate, aluminum diethylphosphinate, zinc diethylphosphinate, calcium methyl-n-propylphosphinate, magnesium methyl-n-propylphosphinate, aluminum methyl-n-propylphosphinate, zinc methyl-n-propylphosphinate, and calcium methane di(methylphosphinate).
• the content of the phosphinate compound (C) is 10.0 parts by mass or more and 22.0 parts by mass or less, preferably 10.0 parts by mass or more and 21.0 parts by mass or less, more preferably 10.0 parts by mass or more and 20.0 parts by mass or less, and even more preferably 15.0 parts by mass or more and 20.0 parts by mass or less, relative to 100 parts by mass of the total mass of the polyamide resin.
• the content 22.0 parts by mass or less it is possible to suppress the decomposition of the polyamide resin by phosphoric acid generated by thermal decomposition of the phosphinate compound (C) during molding. This makes it possible to suppress a decrease in the tensile strength of the molded body.
• the content 10.0 parts by mass or more it is possible to improve the flame retardancy of the molded body.
• the polyamide resin composition preferably contains a reinforcing material (D).
• the content of the reinforcing material (D) is preferably 30% by mass or more, more preferably 35% by mass or more, based on the total mass of the polyamide resin composition.
• the upper limit of the content of the reinforcing material (D) is preferably 50% by mass.
• the reinforcing material may be an inorganic filler.
• reinforcing materials include fibrous reinforcing materials such as glass fiber, wollastonite, potassium titanate whiskers, calcium carbonate whiskers, aluminum borate whiskers, magnesium sulfate whiskers, zinc oxide whiskers, milled fiber, and cut fiber, as well as granular reinforcing materials.
• fibrous reinforcing materials such as glass fiber, wollastonite, potassium titanate whiskers, calcium carbonate whiskers, aluminum borate whiskers, magnesium sulfate whiskers, zinc oxide whiskers, milled fiber, and cut fiber, as well as granular reinforcing materials.
• one type may be used alone, or two or more types may be used in combination.
• wollastonite, glass fiber, and potassium titanate whiskers are preferred, as they tend to increase the mechanical strength of the resin member, and wollastonite and glass fiber are more preferred.
• the average fiber length of the fibrous reinforcing material is preferably 1 ⁇ m or more and 20 mm or less, and more preferably 5 ⁇ m or more and 10 mm or less, from the viewpoints of moldability of the polyamide resin composition and mechanical strength and heat resistance of the resulting resin part.
• the cross-sectional shape of the fibrous reinforcing material may be circular or non-circular, but from the viewpoint of increasing the tensile strength of the molded body, a circular shape is preferable.
• a circular shape is preferable.
• the fibers tend to be oriented in the thickness direction of the thick-walled portion, so a circular shape can provide a stronger reinforcing effect (effect of increasing the tensile strength of the molded body) against cracks that occur inside the thick-walled portion.
• the above cross-sectional shape can be confirmed by observation with an optical microscope.
• the average fiber length and average fiber diameter of the fibrous reinforcing material can be measured by the following method. 1) A polyamide resin composition is dissolved in a hexafluoroisopropanol/chloroform solution (0.1/0.9% by volume), and then filtered to obtain a filtrate. 2) The filtrate obtained in 1) above is dispersed in water, and the fiber length (Li) and fiber diameter (di) of each of 300 randomly selected fibers are measured using an optical microscope (magnification: 50x). The number of fibers with fiber length Li is designated as qi, and the weight average length (Lw) is calculated based on the following formula, which is the average fiber length of the fibrous reinforcing material.
• the content of the reinforcing material (D) is preferably 30 mass% or more, more preferably 35 mass% or more, and even more preferably 40 mass% or more, based on the total mass of the polyamide resin composition.
• the content of the reinforcing material (D) is preferably 30% by mass or more and 50% by mass or less, and more preferably 30% by mass or more and less than 40% by mass, based on the total mass of the polyamide resin composition.
• the polyamide resin (A) having a melting point (Tm) higher than 320°C is melt-kneaded with other components at a higher temperature when preparing the polyamide resin composition. Therefore, from the viewpoint of further suppressing the thermal decomposition of the phosphinate compound (C), it is preferable to suppress the addition of heat such as shear heat to the polyamide resin composition during melt kneading.
• the content of the reinforcing material (D) be 50% by mass or less, shear heat is less likely to occur during melt kneading. This makes it more difficult for the thermal decomposition of the phosphinate compound (C) to occur, suppresses the decomposition of the polyamide resin by phosphoric acid, and further increases the tensile strength of the molded body.
• the polyamide resin composition may contain other known components.
• Examples of other components include flame retardants other than phosphinate compounds, flame retardant auxiliaries, nucleating agents, lubricants, colorants, heat stabilizers, corrosion resistance improvers, drip prevention agents, ion scavengers, elastomers (rubber), antistatic agents, release agents, antioxidants (phenols, amines, sulfurs, phosphorus, etc.), heat stabilizers other than those mentioned above (lactone compounds, vitamin E, hydroquinones, etc.), light stabilizers (benzotriazoles, triazines, benzophenones, benzoates, hindered amines, oxanilides, etc.), other polymers (polyolefins, ethylene-propylene copolymers, olefin copolymers such as ethylene-1-butene copolymers, olefin copolymers such as propylene-1-butene copolymers, polystyrene, polycarbonate, polyacetal, polysulf
• flame retardant assistants include metal oxides and metal hydroxides. Specifically, zinc borate, boehmite, zinc stannate, iron oxide, zinc oxide, and tin oxide are preferred, and zinc borate is more preferred.
• the content of the flame retardant aid is preferably 0.5% by mass or more and 5.0% by mass or less, and more preferably 1.0% by mass or more and 3.0% by mass or less, relative to the total mass of the polyamide resin composition.
• the nucleating agent can promote the crystallization of the polyamide resin (A), thereby making it possible to further increase the tensile strength and elastic modulus of the resin workpiece.
• nucleating agents examples include metal salt-based compounds including sodium 2,2-methylenebis(4,6-di-t-butylphenyl)phosphate, aluminum tris(p-t-butylbenzoate), and stearates; sorbitol-based compounds including bis(p-methylbenzylidene)sorbitol and bis(4-ethylbenzylidene)sorbitol; and inorganic substances including talc, calcium carbonate, and hydrotalcite. Of these, talc is preferred from the viewpoint of further increasing the crystallinity of the resin member. These nucleating agents may be used alone or in combination of two or more.
• Talc generally contains hydrous magnesium silicate (SiO 2 : 58-64%, MgO: 28-32%, Al 2 O 3 : 0.5-5%, Fe 2 O 3 : 0.3-5%) as a main component.
• the average particle size of talc is not particularly limited, but is preferably 1-15 ⁇ m. When the average particle size of talc is within the above range, talc is easily dispersed in polyamide resin (A) without impairing the fluidity of the polyamide resin composition. From the same viewpoint, the average particle size of talc is more preferably 1-7.5 ⁇ m.
• the average particle size of talc can be measured by a laser diffraction method, for example, a laser diffraction method using a Shimadzu particle size distribution analyzer (SALD-2000A type) manufactured by Shimadzu Corporation.
• SALD-2000A type Shimadzu particle size distribution analyzer
• the lubricant enhances the injection flowability of the polyamide resin composition and improves the appearance of the resulting resin part.
• the lubricant can be a metal salt of a fatty acid, such as a metal salt of an oxycarboxylic acid or a metal salt of a higher fatty acid.
• the oxycarboxylic acid constituting the oxycarboxylic acid metal salt may be an aliphatic oxycarboxylic acid or an aromatic oxycarboxylic acid.
• the aliphatic oxycarboxylic acid include aliphatic oxycarboxylic acids having 10 to 30 carbon atoms, such as ⁇ -hydroxymyristic acid, ⁇ -hydroxypalmitic acid, ⁇ -hydroxystearic acid, ⁇ -hydroxyeicosanoic acid, ⁇ -hydroxydocosanoic acid, ⁇ -hydroxytetraeicosanoic acid, ⁇ -hydroxyhexaeicosanoic acid, ⁇ -hydroxyoctaeicosanoic acid, ⁇ -hydroxytriacontanoic acid, ⁇ -hydroxymyristic acid, 10-hydroxydecanoic acid, 15-hydroxypentadecanoic acid, 16-hydroxyhexadecanoic acid, 12-hydroxystearic acid, and ricinoleic acid.
• metals constituting the above metal oxycarboxylates include alkali metals such as lithium, and alkaline earth metals such as magnesium, calcium, and barium.
• the metal salt of oxycarboxylic acid is preferably a metal salt of 12-hydroxystearic acid, and magnesium 12-hydroxystearate and calcium 12-hydroxystearate are more preferred.
• higher fatty acids that make up the above-mentioned higher fatty acid metal salts include higher fatty acids having 15 to 30 carbon atoms, such as stearic acid, oleic acid, behenic acid, behenic acid, and montanic acid.
• metals constituting the above higher fatty acid metal salts include calcium, magnesium, barium, lithium, aluminum, zinc, sodium, and potassium.
• the lubricant content is preferably 0.01% by mass or more and 1.30% by mass or less, based on the total mass of the polyamide resin composition. If the lubricant content is 0.01% by mass or more, the fluidity during molding is likely to be improved, and the appearance of the resulting molded product is likely to be improved. If the lubricant content is 1.30% by mass or less, gas due to decomposition of the lubricant is unlikely to be generated during molding, and the product's appearance is likely to be good.
• Colorant imparts a desired color tone to the resin member.
• the colorant is not particularly limited, but may be a pigment.
• pigments include inorganic pigments such as carbon black, alumina, titanium oxide, chromium oxide, iron oxide, zinc oxide, and barium sulfate, and organic pigments such as azo pigments, phthalocyanine pigments, quinacridone pigments, perylene pigments, anthraquinone pigments, thioindigo pigments, and indanthrene pigments.
• the content of the colorant is preferably from 0.01% by mass to 5.00% by mass, and more preferably from 0.10% by mass to 2.00% by mass, based on the total mass of the polyamide resin composition.
• the colorant imparts a desired color tone to the resin member.
• the colorant is not particularly limited, but may be a pigment.
• the pigment include inorganic pigments such as carbon black, alumina, titanium oxide, chromium oxide, iron oxide, zinc oxide, and barium sulfate, and organic pigments such as azo pigments, phthalocyanine pigments, quinacridone pigments, perylene pigments, anthraquinone pigments, thioindigo pigments, and indanthrene pigments.
• the colorant content is preferably 0.01% by mass or more and 5.00% by mass or less, and more preferably 0.10% by mass or more and 2.00% by mass or less, based on the total mass of the polyamide resin composition.
• the polyamide resin composition can be produced by a known resin kneading method, for example, by mixing the above-mentioned polyamide resin (A), polyamide resin (B), phosphinic acid salt compound (C), and other components as necessary, with a Henschel mixer, V blender, ribbon blender, or tumbler blender, or by mixing, melt-kneading with a single-screw extruder, multi-screw extruder, kneader, or Banbury mixer, and then granulating or pulverizing.
• the melting temperature during melt-kneading is preferably the melting point (Tm) of the polyamide resin (A) + 10°C or higher and the melting point (Tm) of the polyamide resin (A) + 20°C or lower.
• the molded body can be manufactured by a normal melt molding method, such as compression molding or injection molding, using the polyamide resin composition described above.
• the gate size is preferably ⁇ 0.5 mm or more from the viewpoint of filling the resin sufficiently.
• the polyamide resin composition of the present invention can be put into an injection molding machine in which the cylinder temperature is adjusted to a temperature equal to or higher than the melting point of the polyamide resin (A), for example, about 280°C to 350°C, to produce a molten state, and then introduced into a mold of a given shape to produce a molded article.
• the cylinder temperature is adjusted to a temperature equal to or higher than the melting point of the polyamide resin (A), for example, about 280°C to 350°C, to produce a molten state, and then introduced into a mold of a given shape to produce a molded article.
• Examples of applications of molded articles made from the polyamide resin composition of this embodiment include vehicle structural parts, vehicle mounted items, housings for electronic devices, housings for home appliances, structural parts, machine parts, various automotive parts, electronic device parts, medical devices, etc.
• vehicle-related parts include pyrofuses, instrument panels, console boxes, doorknobs, door trim, shift levers, pedals, glove boxes, bumpers, bonnets, fenders, trunks, doors, roofs, pillars, seats, steering wheels, bus bars, terminals, terminal blocks, high-voltage connectors, motors, power conversion devices (inverters, converters), ECU boxes, electrical components, engine peripheral parts, drive system and gear peripheral parts, intake and exhaust system parts, and cooling system parts.
• Precision electronic parts include connectors, relays, gears, etc.
• Synthesis/preparation of materials 1-1 Synthesis of polyamide resin (A) ⁇ Polyamide resin (A-1) (6T66)> 2800g (24.1 mol) of 1,6-diaminohexane, 2184g (13.1 mol) of terephthalic acid, 1572g (10.8 mol) of adipic acid, 5.67g (5.4 ⁇ 10-2 mol) of sodium hypophosphite monohydrate as a catalyst, 36.5g (0.30 mol) of benzoic acid as a molecular weight regulator, and 545g of distilled water were placed in an autoclave with a capacity of 13.6L and substituted with nitrogen. Stirring was started from 190°C, and the internal temperature was raised to 250°C over 3 hours.
• the internal pressure of the autoclave was raised to 3.03 MPa.
• the low-order condensate was discharged into the air from a spray nozzle installed at the bottom of the autoclave and extracted. Thereafter, the low-order condensate was cooled to room temperature, pulverized to a particle size of 1.5 mm or less with a pulverizer, and dried at 110°C for 24 hours.
• the resulting low-order condensate had an intrinsic viscosity [ ⁇ ] of 0.15 dl/g.
• this low-order condensate was placed in a tray-type solid-phase polymerization apparatus, and after replacing with nitrogen, the temperature was raised to 180°C over approximately 1 hour and 30 minutes. After that, the reaction was allowed to continue for 1 hour and 30 minutes, and the temperature was lowered to room temperature.
• the resulting polyamide resin (A-1) had an intrinsic viscosity [ ⁇ ] of 1.00 dl/g, a melting point (Tm) of 310°C, a glass transition temperature (Tg) of 85°C, and a heat of fusion ( ⁇ H) of 50 J/g.
• the composition of the resulting polyamide resin (A-1) was such that the content of component units derived from terephthalic acid in the component units derived from dicarboxylic acid was 55 mol%, the content of component units derived from adipic acid was 45 mol%, and the content of component units derived from 1,6-diaminohexane in the component units derived from diamine was 100 mol%.
• Polyamide resin (A-2) was obtained in the same manner as in the synthesis of polyamide resin (A-1), except that the raw materials used were changed to 2475 g (14.9 mol) of terephthalic acid, 2905 g (25.0 mol) of 1,6-hexanediamine, and 1300 g (8.9 mol) of adipic acid.
• the resulting polyamide resin (A-2) had an intrinsic viscosity [ ⁇ ] of 0.80 dl/g, a melting point (Tm) of 320°C, a glass transition temperature (Tg) of 95°C, and a heat of fusion ( ⁇ H) of 50 J/g.
• the resulting polyamide resin (A-1) had a composition in which the content of component units derived from terephthalic acid in the component units derived from dicarboxylic acid was 62.5 mol%, the content of component units derived from adipic acid was 37.5 mol%, and the content of component units derived from 1,6-diaminohexane in the component units derived from diamine was 100 mol%.
• Polyamide resin (A-3) was obtained in the same manner as in the synthesis of polyamide resin (A-1), except that the raw materials were changed to 2774 g (16.7 mol) of terephthalic acid, 2800 g (24.1 mol) of 1,6-hexanediamine, and 1196 g (7.2 mol) of isophthalic acid.
• the resulting polyamide resin (A-3) had an intrinsic viscosity [ ⁇ ] of 1.00 dl/g, a melting point (Tm) of 330°C, a glass transition temperature (Tg) of 125°C, and a heat of fusion ( ⁇ H) of 50 J/g.
• the composition of the resulting polyamide resin (A-3) was such that the content of component units derived from terephthalic acid in the component units derived from dicarboxylic acid was 70 mol%, the content of component units derived from isophthalic acid was 30 mol%, and the content of component units derived from 1,6-diaminohexane in the component units derived from diamine was 100 mol%.
• Polyamide resin (B) (6I6T) Polyamide resin (B) was obtained in the same manner as in the synthesis of polyamide resin (A-1), except that the raw materials were changed to 2581 g (15.5 mol) of isophthalic acid, 2800 g (24.1 mol) of 1,6-diaminohexane, and 1390 g (8.4 mol) of terephthalic acid.
• the intrinsic viscosity [ ⁇ ] of the obtained polyamide resin (B) was 0.54 dl/g, the melting point (Tm) was not measured, the glass transition temperature (Tg) was 125°C, and the heat of fusion ( ⁇ H) was 0 J/g.
• the composition of the obtained polyamide resin (B) was such that the content of component units derived from terephthalic acid in the component units derived from dicarboxylic acid was 35 mol%, the content of component units derived from isophthalic acid was 65 mol%, and the content of component units derived from 1,6-diaminohexane in the component units derived from diamine was 100 mol%.
• Phosphinate compound (C) As the phosphinate compound, aluminum phosphinate (Exolit OP-1230, manufactured by Clariant) was used.
• Reinforcement material (D) Glass fiber (ECS03T-262H, cross-sectional shape: circular, manufactured by Nippon Electric Glass Co., Ltd.) was used as a reinforcing material.
• Flame retardant assistant 1 Zinc borate
• Flame retardant assistant 2 Zinc oxide
• Lubricant Calcium montanate was used as the lubricant.
• Tm melting point
• Tg glass transition temperature
• the melting point (Tm) and glass transition temperature (Tg) of the polyamide resin were measured using a differential scanning calorimeter (DSC220C type, manufactured by Seiko Instruments Inc.). Specifically, about 5 mg of the polyamide resin was sealed in an aluminum pan for measurement and set in the differential scanning calorimeter. Then, the polyamide resin was heated from room temperature to 350°C at 10°C/min. In order to completely melt the resin, the resin was held at 350°C for 3 minutes, and then cooled to 30°C at 10°C/min. After being left at 30°C for 5 minutes, the resin was heated a second time to 350°C at 10°C/min. The temperature (°C) of the endothermic peak in this second heating was taken as the melting point (Tm) of the polyamide resin, and the transition point corresponding to the glass transition was taken as the glass transition temperature (Tg).
• DSC220C type differential scanning calorimeter
• ⁇ Heat of fusion ( ⁇ H)> The heat of fusion ( ⁇ H) of the polyamide resin was determined from the area of the exothermic peak of crystallization during the first heating process in accordance with JIS K 7122 (2012).
• the intrinsic viscosity [ ⁇ ] of the polyamide resin was determined by dissolving 0.5 g of the polyamide resin in 50 ml of a 96.5% sulfuric acid solution, measuring the flow time of the resulting solution at 25° C. ⁇ 0.05° C.
• test pieces were left at 23°C in a nitrogen atmosphere for 24 hours. Then, in accordance with ISO 527, a tensile test was performed at -40°C and 50% relative humidity to measure the tensile strength and tensile elongation.
• Each polyamide resin composition was injection molded under the following conditions to prepare test pieces of 1/32 inch x 1/2 x 5 inch. Using the prepared test pieces, a vertical flame test was carried out in accordance with the UL94 standard (UL Test No. UL94 dated June 18, 1991) to evaluate the flame retardancy.
• Molding machine Tupearl TR40S3A, manufactured by Sodick Plastic Co., Ltd. Molding machine cylinder temperature: Melting point of each polyamide resin (A) + 10°C Mold temperature: glass transition temperature of each polyamide resin (A) + 35
• Corrosion wear evaluation> (Evaluation Method) Using a connector mold having 14 terminals (weight of molded product including sprue and runner: 1 g), 10,000 shots of continuous injection molding were carried out.
• Injection molding machine Sumitomo Heavy Industries, Ltd., SE50DU Molding machine cylinder setting temperature: Melting point of each polyamide resin (A) + 10°C Mold temperature: 100°C
• the weights of the screw parts of the injection unit were measured before and after injection molding, and the corrosion wear rate was calculated by the following formula.
• Corrosion wear rate (%) ⁇ (weight of screw part before injection molding - weight of screw part after injection molding) / weight of screw part before injection molding ⁇ x 100
• Tables 1 and 2 show the composition and evaluation results of each polyamide resin composition.
• the composition values in Tables 1 and 2 represent parts by mass.
• polyamide resin compositions 1 to 8 show that when a molded article having a thick wall is produced, if the polyamide resin (A) has an intrinsic viscosity of 0.9 dl/g or more, contains 20 mass% or less of a flame retardant, and contains polyamide resin (B) whose melting point is essentially unmeasurable, the molded article can have good flame retardancy while having high tensile strength.
• the polyamide resin composition of the present invention can increase the tensile strength of a molded article having a thick wall portion and can improve the flame retardancy of the molded article when produced. Therefore, the molded article using the polyamide resin composition is useful for, for example, automobile parts.

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