TWI810165B - Polyamide resin and moldings - Google Patents

Abstract

The present invention provides an amorphous polyamide resin excellent in Sharpey impact strength and thermal aging resistance, and a molded article containing the polyamide resin. A polyamide resin containing structural units derived from diamine and structural units derived from dicarboxylic acid, wherein more than 70 mol% of the structural units derived from diamine are derived from 1,4-bis(aminomethyl)cyclohexyl The structural unit of alkane, in the 1,4-bis(aminomethyl)cyclohexane constituting the structural unit derived from diamine, the molar ratio (cis/trans) of the cis-isomer and trans-isomer is 90/10 ~20/80, the constituent units derived from dicarboxylic acids contain constituent units derived from isophthalic acid and constituent units derived from straight-chain aliphatic dicarboxylic acids with 8 to 12 carbons, and substantially no constituents derived from p- The constituent unit of phthalic acid is amorphous.

Description

Polyamide resin and molded products

The present invention relates to novel polyamide resins and molded articles. In particular, polyamide resins and molded articles thereof are excellent in Sharpey impact strength and heat aging resistance.

A polyamide resin obtained by polycondensing bis(aminomethyl)cyclohexane and dicarboxylic acid has been discussed in the past. For example, Patent Document 1 discloses a diamine component containing more than 40 mol% of bis(aminomethyl)cyclohexane and a diamine component containing more than 50 mol% of isophthalic acid and/or terephthalic acid. Heat-resistant polyamide resin composed of carboxylic acid components. However, Patent Document 1 does not specifically disclose the use of a polymer of 1,4-bis(aminomethyl)cyclohexane as bis(aminomethyl)cyclohexane, including Examples and the like. [Prior Art Document] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open No. 2010-285553

[Problems to be Solved by the Invention] Crystalline resins are prone to burrs when molded, but amorphous resins have the advantage that burrs are less likely to occur even when molded. Therefore, amorphous resins have been used in films, sunglasses, etc. until now. However, amorphous resins are not used in such applications because they are not good in performance required for engineering plastic applications such as Sharpey impact strength and heat aging resistance. The object of the present invention is to solve this problem, and to provide a polyamide resin which is an amorphous resin and has excellent Sharpey impact strength and heat aging resistance, and to provide a molded article containing the polyamide resin. [Means to solve the problem]

Based on this situation, the present inventors made intensive studies and found that by using a constituent unit derived from 1,4-bis(aminomethyl)cyclohexane as a constituent unit derived from diamine, a constituent unit derived from isophthalic acid was used. Units and structural units derived from straight-chain aliphatic dicarboxylic acids with 8 to 12 carbons are used as structural units derived from dicarboxylic acids to produce amorphous resins, and 1,4-bis(aminomethyl)cyclohexane The molar ratio of the cis-isomer and trans-isomer is a predetermined ratio, which can provide a resin with high sand ratio impact strength and excellent heat aging resistance. Specifically, find the following means <1>, ideally according to <2>-<8> can solve the above problems. <1> A polyamide resin comprising a structural unit derived from a diamine and a structural unit derived from a dicarboxylic acid, wherein 70 mol% or more of the structural unit derived from a diamine is derived from 1,4-bis(aminomethyl ) structural unit of cyclohexane, and in 1,4-bis(aminomethyl)cyclohexane constituting the structural unit derived from diamine, the molar ratio (cis/trans) between the cis-isomer and the trans-isomer is 90/10~20/80, the constituent units derived from dicarboxylic acids contain constituent units derived from isophthalic acid and constituent units derived from straight-chain aliphatic dicarboxylic acids with 8 to 12 carbons, and substantially do not contain constituent units derived from The constituent unit of terephthalic acid is amorphous. <2> The polyamide resin according to <1>, wherein 10 to 90 mole % of the structural units derived from dicarboxylic acid are derived from isophthalic acid, and 90 to 10 mole % are derived from straight dicarboxylic acid having 8 to 12 carbon atoms. chain aliphatic dicarboxylic acids. <3> The polyamide resin according to <1> or <2>, wherein the straight-chain aliphatic dicarboxylic acid having 8 to 12 carbon atoms is sebacic acid. <4> The polyamide resin according to any one of <1> to <3>, wherein the polyamide resin has a glass transition temperature of 100 to 190°C. <5> The polyamide resin according to any one of <1> to <4>, wherein the unnotched Sandpy impact strength according to JIS K7111-1 is 150 kJ/m ² or more. <6> The polyamide resin according to any one of <1> to <5>, wherein the polyamide resin has a number average molecular weight of 8,000 to 25,000. <7> The polyamide resin according to any one of <1> to <6>, wherein, in the 1,4-bis(aminomethyl)cyclohexane constituting the structural unit derived from diamine, the The molar ratio (cis/trans) of the body to the trans body is 70/30~30/70. <8> A molded article formed by molding a composition containing the polyamide resin according to any one of <1> to <7>. [Effect of Invention]

According to the present invention, an amorphous polyamide resin excellent in Sharpey impact strength and thermal aging resistance, and a molded article containing the polyamide resin can be provided.

The content of the present invention will be described in detail below. In addition, "~" in this specification uses the numerical value described before and after that as a lower limit value and an upper limit value and is used in the meaning included.

In the polyamide resin of the present invention, the structural unit derived from diamine and the structural unit derived from dicarboxylic acid are contained, and more than 70 mol% of the structural unit derived from diamine is derived from 1,4-bis(aminomethyl ) structural unit of cyclohexane, and in 1,4-bis(aminomethyl)cyclohexane constituting the structural unit derived from diamine, the molar ratio (cis/trans) between the cis-isomer and the trans-isomer is 90/10~20/80, the constituent units derived from dicarboxylic acids contain constituent units derived from isophthalic acid and constituent units derived from straight-chain aliphatic dicarboxylic acids with 8 to 12 carbons, and substantially do not contain constituent units derived from The constituent unit of terephthalic acid is amorphous. In the present invention, by using a straight-chain aliphatic dicarboxylic acid with 8 to 12 carbons as the dicarboxylic acid component polymerized with 1,4-bis(aminomethyl)cyclohexane, compared with the use of a carbon number 7 The following linear aliphatic dicarboxylic acids (for example, adipic acid) can improve heat aging resistance. In addition, by using isophthalic acid as the dicarboxylic acid component, an amorphous resin was successfully obtained without reducing the heat aging resistance. In particular, as a dicarboxylic acid component, when terephthalic acid was used, heat aging resistance was particularly low, but by using isophthalic acid, an amorphous resin was successfully obtained while maintaining heat aging resistance.

In the present invention, 70 mol% or more of the structural units derived from diamine are derived from 1,4-bis(aminomethyl)cyclohexane. In the present invention, the constituent unit derived from diamine is preferably at least 80 mol%, more preferably at least 90 mol%, more preferably at least 95 mol%, still more preferably at least 98 mol%. More preferably, more than 99 mol% is derived from 1,4-bis(aminomethyl)cyclohexane. Examples of diamines other than 1,4-bis(aminomethyl)cyclohexane include 1,3-bis(aminomethyl)cyclohexane, tetramethylenediamine, pentamethylene Diamine, hexamethylenediamine, octamethylenediamine, nonamethylenediamine and other aliphatic diamines, p-phenylenediamine, m-xylylenediamine, p-xylylenediamine and other aromatics Diamine etc. These other diamines may be one kind or two or more kinds. In the present invention, the molar ratio (cis/trans) of the cis-form and trans-form of 1,4-bis(aminomethyl)cyclohexane, which is the raw material diamine of the polyamide resin, is 90/10~ 20/80. With such a configuration, an amorphous polyamide resin having excellent Sharpey impact strength can be obtained. The molar ratio (cis/trans) of the cis-isomer and trans-isomer is more preferably 90/10~30/70, more preferably 70/30~30/70, and more preferably 65/35~ 35/65, more preferably 65/35~40/60, especially more preferably 65/35~51/49, especially more preferably 60/40~55/45.

In the present invention, 10 to 90 mol% of the structural units derived from dicarboxylic acid are derived from isophthalic acid, 90 to 10 mol% are derived from straight-chain aliphatic dicarboxylic acids with 8 to 12 carbon atoms, and substantially no It is desirable to contain a constituent unit derived from terephthalic acid. Here, terephthalic acid is not substantially contained. For example, among all dicarboxylic acids constituting structural units derived from dicarboxylic acids, terephthalic acid is 5 mol % or less, preferably 4 mol % or less, and 3 mol % or less. mol% or less is more desirable, and 1 mol% or less is more desirable. The lower limit may be 0 mol%. The lower limit of the ratio of isophthalic acid among all the dicarboxylic acids constituting the structural units derived from dicarboxylic acids is more preferably 20 mol % or more, more preferably 30 mol % or more, 35 mol % or more Still more preferably, 40 mol% or more is still more preferable, and even 45 mol% or more is acceptable. The polyamide resin of the present invention can be rendered amorphous by adjusting the lower limit of the ratio of isophthalic acid. The upper limit of the ratio of isophthalic acid is more preferably 80 mol % or less, more preferably 70 mol % or less, more preferably 65 mol % or less, and more preferably 60 mol % or less. 55 mol% or less is also acceptable. By adjusting the upper limit of the ratio of isophthalic acid, the glass transition temperature (Tg) can be increased.

Among all the dicarboxylic acids constituting the structural units derived from dicarboxylic acids, the lower limit of the proportion of straight-chain aliphatic dicarboxylic acids with 8 to 12 carbon atoms is preferably 20 mole % or more, preferably 30 mole % The above is more desirable, 35 mol% or more is still more desirable, 40 mol% or more is further more desirable, and 45 mol% or more is also possible. The upper limit of the ratio of the straight-chain aliphatic dicarboxylic acid with 8 to 12 carbon atoms is preferably 80 mole % or less, more preferably 70 mole % or less, more preferably 65 mole % or less, and 60 mole % or less. Mole% or less is still more preferable, and even if it is less than 60 mol%, it may be 58 mol% or less, 55 mol% or less, or 53 mol% or less. Within such a range, the heat aging resistance of the polyamide resin tends to be further improved, which is ideal. As far as straight-chain aliphatic dicarboxylic acids with 8-12 carbons are concerned, α, ω-straight-chain aliphatic dicarboxylic acids with 8-12 carbons are more ideal, suberic acid, azelaic acid, sebacic acid, 1 ,9-nonanedicarboxylic acid and 1,10-decanedicarboxylic acid are more preferable, and sebacic acid is particularly preferable. One or more straight-chain aliphatic dicarboxylic acids having 8 to 12 carbon atoms may be used.

Among all the dicarboxylic acids constituting the structural units derived from dicarboxylic acids, the ratio of the total of isophthalic acid to straight-chain aliphatic dicarboxylic acids with 8 to 12 carbon atoms is preferably 90 mol % or more, ideally 95 mol % mol% or more is more desirable, 98 mol% or more is more desirable, and 100 mol% is also acceptable.

For dicarboxylic acids other than isophthalic acid and straight-chain aliphatic dicarboxylic acids with 8 to 12 carbon atoms, aliphatic dicarboxylic acids with 7 or less carbon atoms, alicyclic dicarboxylic acids with 6 to 12 carbon atoms can be exemplified. Carboxylic acid etc. Specific examples thereof include succinic acid, glutaric acid, adipic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, and the like.

In the present invention, as an ideal embodiment of the constituent unit derived from dicarboxylic acid, 30 to 70 mol% is derived from isophthalic acid, and 70 to 30 mol% is derived from straight-chain aliphatic dicarboxylic acid having 8 to 12 carbon atoms. The form of carboxylic acid. In this embodiment, the constituent unit derived from other dicarboxylic acids is preferably 0 to 3 mol%. The more preferable range of this embodiment is the same as the said preferable range.

In addition, the polyamide resin of the present invention contains a structural unit derived from a dicarboxylic acid and a structural unit derived from a diamine, but may also contain a structural unit other than a structural unit derived from a dicarboxylic acid and a structural unit derived from a diamine, and a terminal group. Wait for other parts. As for other constituent units, lactams derived from ε-caprolactam, valerolactamide, lauryl lactam, undecyl lactam, etc., 11-aminoundecanoic acid, 12- Structural units such as aminocarboxylic acids such as aminododecanoic acid, but are not limited thereto. Furthermore, the polyamide resin of the present invention may contain trace components such as additives for synthesis. The polyamide resin used in the present invention is usually at least 95% by weight, preferably at least 98% by weight, more preferably at least 99% by weight, of structural units derived from dicarboxylic acids or structural units derived from diamines.

The polyamide resin of the present invention is produced by adding a compound containing a phosphorus atom and utilizing a melt polycondensation (melt polymerization) method. The melt polycondensation method is a method in which the raw material diamine is added dropwise to the molten raw material dicarboxylic acid, the temperature is raised under pressure, and the condensation water is removed while polymerizing, or the raw material diamine and the raw material dicarboxylic acid are combined. In the presence of water, the formed salt is heated under pressure, and the method of polymerizing it in a molten state while removing added water and condensation water is ideal.

The compounds containing phosphorus atoms added to the polycondensation system of the polyamide resin of the present invention include dimethylphosphinic acid, phenylmethylphosphinic acid, hypophosphorous acid, sodium hypophosphite, hypophosphorous acid Potassium, lithium hypophosphite, calcium hypophosphite, ethyl hypophosphite, phenylphosphonous acid, sodium phenylphosphinate, potassium phenylphosphinate, lithium phenylphosphinate, ethyl phenylphosphinate, Phenylphosphonic acid, ethylphosphonic acid, sodium phenylphosphonate, potassium phenylphosphonate, lithium phenylphosphonate, diethyl phenylphosphonate, sodium ethylphosphonate, potassium ethylphosphonate, phosphorous acid , sodium hydrogen phosphite, sodium phosphite, triethyl phosphite, triphenyl phosphite, pyrophosphorous acid, etc. Among them, hypophosphite such as sodium hypophosphite, potassium hypophosphite, lithium hypophosphite, calcium hypophosphite, etc. Metal salts are highly effective in accelerating the amidation reaction and are excellent in preventing coloration, and are ideal, especially calcium hypophosphite. The phosphorus atom-containing compound usable in the present invention is not limited to these compounds.

The polyamide resin of the present invention obtained by melt polycondensation should be taken out first, granulated, and then dried before use.

The melt viscosity of the polyamide resin of the present invention at a shear rate of 122sec ^-1 and 280°C is more preferably 500Pa·s or higher, more preferably 1000Pa·s or higher, and more preferably 1200Pa·s or higher. In addition, the melt viscosity is preferably not more than 5000Pa·s, more preferably not more than 3500Pa·s, more preferably not more than 3000Pa·s, and further, not more than 2800Pa·s, even if it is not more than 2500Pa·s, not more than 2000Pa·s, Below 1800Pa・s, 1600Pa・s is also acceptable. The method of measuring the melt viscosity is based on the method described in the examples described later. If the equipment used in the examples is difficult to obtain due to production suspension, etc., other equipment with equivalent performance can be used. Hereinafter, the same applies to other measurement methods.

For the polyamide resin of the present invention, the lower limit of the number average molecular weight is more preferably 8,000 or more, more preferably 10,000 or more, and more preferably 11,000 or more. The upper limit of the number average molecular weight is preferably 25,000 or less, more preferably 20,000 or less, and may be 17,000 or less. The measuring method of the number average molecular weight is based on the method described in the Example mentioned later.

For the polyamide resin of the present invention, the glass transition temperature is more ideally above 100°C, more preferably above 120°C, more preferably above 125°C, more preferably above 128°C, more preferably above 130°C, and above 135°C Further more ideal. In the present invention, such a high Tg can be achieved, so there is an advantage that the physical properties are not easily reduced even under high temperature conditions. Although the upper limit of the glass transition temperature is not particularly limited, for example, it is preferably 190°C or lower, and even 170°C or lower, 160°C or lower, and 150°C or lower are sufficient for practical use. The method of measuring the glass transition temperature is based on the method described in the examples described later.

The polyamide resin of the present invention can be used as an amorphous polyamide resin. Here, the amorphous polyamide resin refers to a resin without a clear melting point. Specifically, it refers to a crystal melting enthalpy (enthalpy) ΔHm of less than 5 J/g, preferably less than 3 J/g, and less than 1 J/g more ideal.

The polyamide resin of the present invention preferably has a haze of 5.0% or less, more preferably 4.8% or less, even more preferably 4.5% or less, and still more preferably 4.3% or less, and even 4.0% for a molded product with a thickness of 2 mm. % or less, 3.4% or less, 3.0% or less, or 2.5% or less are also acceptable. As for the lower limit of the haze, 0% is ideal, but even if it is 0.001% or more, there is no practical problem. The haze in the present invention is a value measured according to the method described in Examples described later.

The polyamide resin of the present invention is a polyamide resin excellent in mechanical strength. For the polyamide resin of the present invention, according to JIS K7111-1, the unnotched sand specific impact strength should be more than 150kJ/ ^m2 , ideally above 180kJ/ ^m2 , more ideally above 200kJ/ ^m2 , even if 230kJ/m2 More than m ² and 250kJ/m ² or more are also acceptable. The upper limit is desirably NB (non-destructive), and even 400 kJ/m ² or less and 300 kJ/m ² or less are sufficient for practical use.

The polyamide resin of the present invention can be used in the form of a molded article obtained by molding a composition containing the polyamide resin of the present invention. The composition may consist of only one or two or more polyamide resins of the present invention, or may contain other components. In terms of other components, other polyamide resins other than the polyamide resin of the present invention, thermoplastic resins other than polyamide resins, fillers, matting agents, heat-resistant stabilizers, and weather-resistant stabilizers can be added as needed , UV absorbers, plasticizers, flame retardants, antistatic agents, anti-coloring agents, antigelling agents, impact modifiers, lubricants, colorants, conductive additives and other additives. These additives may each be 1 type or 2 or more types. As for other polyamide resins, specifically, polyamide 6, polyamide 66, polyamide 46, polyamide 6/66 (composed of polyamide 6 components and polyamide 66 components) can be exemplified. Copolymer), polyamide 610, polyamide 612, polyamide 11, polyamide 12, MXD6 (polyadipamide-m-phenylenediamine), MPXD6 (polyadipamide-m-phenylenediamine) . Each of these other polyamide resins may be one type, or two or more types. Examples of thermoplastic resins other than polyamide resins include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate. polyester resins such as esters. The thermoplastic resins other than these polyamide resins may be of one type or two or more types.

The composition containing the polyamide resin of the present invention can be blended with reinforcing fibers to form a fiber-reinforced resin composition. Examples of reinforcing fibers include carbon fibers and glass fibers. Examples of the fiber-reinforced resin composition include pellets obtained by melt-kneading a composition containing the polyamide resin of the present invention and reinforcing fibers, and pellets obtained by impregnating the polyamide resin of the present invention into reinforcing fibers. In terms of fiber components, prepregs include mixed yarns, braided ropes or twisted yarns containing continuous thermoplastic resin fibers containing the polyamide resin of the present invention and continuous reinforcing fibers. Fabrics or braids of continuous thermoplastic resin fibers and continuous reinforcing fibers of polyamide resin, non-woven fabrics composed of thermoplastic resin fibers and reinforcing fibers containing polyamide resin of the present invention, etc.

The composition containing the polyamide resin of the present invention can be molded by known molding methods such as injection molding, blow molding, extrusion molding, compression molding, stretching, and vacuum molding.

Molded products containing the polyamide resin of the present invention can be used for various molded products including films, films, thin-walled molded products, hollow molded products, fibers, hoses, pipe fittings, and the like. An example of an embodiment of the molded article of the present invention includes a single-layer or multi-layer container including a layer formed of a composition containing the polyamide resin of the present invention. As such a multilayer container, a multilayer container having the following order: a layer formed of a composition containing a polyolefin resin, a layer formed of a polyamide resin of the present invention, and a layer formed of a composition containing a polyolefin resin can be exemplified. layer. As polyolefin resin, polypropylene (PP), cycloolefin polymer (COP), and cycloolefin copolymer (COC) can be illustrated. Furthermore, an adhesive layer may be provided between the layer formed of the composition containing the polyolefin resin and the layer formed of the polyamide resin of the present invention. Such a multilayer container can be suitably used as a container for food and medicine. Examples of containers for pharmaceuticals include ampoules, vials, vacuum blood collection tubes, and prefilled syringes. Also, the composition containing the polyamide resin of the present invention is suitable for engineering plastics. In terms of the application field of the molded product, there are conveyor parts such as automobiles, general machine parts, precision machine parts, electronics, etc. Electrical machine parts, OA machine parts, building materials. Household equipment-related parts, medical equipment, leisure sports goods, game machines, medical products, daily necessities such as films for food packaging, defense and aerospace products, etc. [Example]

The following examples are given to further specifically describe the present invention. The materials, usage amounts, ratios, processing contents, processing flow, etc. shown in the following examples can be appropriately changed without departing from the scope of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.

Example 1 <Synthesis of Resin A> Equipped with a stirrer, a partial condenser, a total condenser, a pressure regulator, a thermometer, a drip tank, a pump, an aspirator, a nitrogen inlet pipe, a tank bottom valve, and a wire drawing In a pressure-resistant reaction vessel with an internal volume of 50 L in the die head, 7000 g (34.61 mol) of sebacic acid (manufactured by Ito Essential Oil Co., Ltd.) and isophthalic acid (manufactured by A・G・International・Chemical (AGIC) Co., Ltd.) 5750g (34.61mol), calcium hypophosphite (manufactured by Kanto Chemical Co., Ltd.) 3.3g (0.019mol), sodium acetate (manufactured by Kanto Chemical Co., Ltd.) 1.4g (0.018mol) were put in, and after nitrogen was fully replaced, the reaction vessel was sealed. , and while maintaining the inside of the container at 0.4 MPa, the temperature was raised to 200° C. under stirring. After reaching 200°C, for the raw materials in the reaction vessel, start to drop 1,4-bis(aminomethyl)cyclohexane (cis/trans (molar ratio): 60/ 40) (manufactured by Mitsubishi Gas Chemical Co., Ltd.) 9847 g (69.22 mol), while maintaining the inside of the container at 0.4 MPa while removing the generated condensation water to the outside of the system, and simultaneously raising the temperature inside the reaction tank to 295°C. After the dropwise addition of 1,4-BAC was completed, the inside of the reaction vessel was slowly returned to normal pressure, and then the inside of the reaction tank was decompressed to 80 kPa using an aspirator to remove condensation water. Observe the stirring torque of the mixer under decompression, stop stirring when it reaches the set torque, pressurize the reaction tank with nitrogen, and open the bottom valve of the barrel, draw the polymer from the wire drawing die, and cool after stranding , and be pelletized by a pelletizer to obtain a polyamide resin. The following evaluations were performed on the obtained polyamide resin. The results are shown in Table 1.

<Measurement of Melt Viscosity> The melt viscosity of polyamide resin is measured by CAPPILOGRAPH, using a die head with a diameter of 1mm x 10mm, at an apparent shear rate of 122sec ^-1 , at a measurement temperature of 280°C, and for a holding time of 6 minutes. Measured under conditions with a water content of 1000 ppm by weight or less. In this example, CAPPILOGRAPH-1 manufactured by Toyo Seiki Co., Ltd. was used for CAPPILOGRAPH.

<Measurement of glass transition temperature (Tg)> Glass transition temperature is measured by using a differential scanning calorimeter (DSC), heating from room temperature to 250 °C at a heating rate of 10 °C/min in a nitrogen stream, and immediately cooling to below room temperature. Again, the glass transition temperature was heated from room temperature to 250 ℃ at a heating rate of 10° C./min. In this example, DSC-60 manufactured by Shimadzu Corporation was used as a differential scanning calorimeter. In addition, according to JIS K7121 and K7122, the crystal melting enthalpy ΔHm of the polyamide resin during the heating process was measured.

<Determination of Number Average Molecular Weight (Mn)> Put 0.3g of polyamide resin into a mixed solvent of phenol/ethanol=4/1 (volume ratio), stir at 20~30°C, after completely dissolved, add methanol while stirring Rinse the inner wall of the container with 5mL, neutralize and titrate with 0.01mol/L hydrochloric acid aqueous solution, and obtain the terminal amino group concentration [NH ₂ ]. Also, stir 0.3g of polyamide resin in benzyl alcohol at 160~180°C under nitrogen flow, and after it is completely dissolved, cool to below 80°C under nitrogen flow, wash the inner wall of the container with 10mL of methanol while stirring, mol/L sodium hydroxide aqueous solution to neutralize and titrate to obtain the terminal carboxyl group concentration [COOH]. From the measured terminal amino group concentration [NH ₂ ] (unit: μ equivalent/g) and terminal carboxyl group concentration [COOH] (unit: μ equivalent/g), the number average molecular weight was obtained according to the following formula. Number average molecular weight (Mn) = 2,000,000/(［COOH］＋［NH ₂ ］)

<Measurement of Haze> The obtained polyamide resin pellets were vacuum-dried at 120°C (dew point -40°C) for 24 hours, and the dried pellets were injected into an injection molding machine (Sumitomo Heavy Industries Co., Ltd., SE130DU-HP), under the conditions of mold temperature 100°C and cylinder temperature 280°C, a test piece with a thickness of 2mm was produced. The haze value was measured by the transmission method using a haze measuring device. In the present example, the haze measuring device was manufactured by Nippon Denshoku Kogyo Co., Ltd., model: COH-300A.

<Evaluation of Heat Aging Resistance (120°C)> The obtained polyamide resin pellets were vacuum-dried at 120°C (dew point -40°C) for 24 hours, and then molded on an injection molding machine (Sumitomo Heavy Industries Co., Ltd., SE130DU) -HP), under the conditions of mold temperature 100°C and cylinder temperature 280°C, a test piece of 4mm×10mm×80mm was produced. The test piece was heated at an internal temperature of 120° C. with a hot air dryer (manufactured by Yamato Science Co., Ltd., DF611). After 60 days, take it out, measure the flexural strength (MPa) in accordance with ISO178 with AUTOGRAPH (manufactured by Toyo Seiki Co., Ltd., BENDGRAPH) at 23°C and 50%RH, and obtain the strength retention rate (%) from the initial value, and evaluate The way is as follows. A: The bending strength retention rate is more than 80% B: The bending strength retention rate is more than 50% but less than 80% C: The bending strength retention rate is less than 50%

<Sharpy impact strength> The obtained polyamide resin pellets were vacuum-dried at 120°C (dew point -40°C) for 24 hours, and then molded on an injection molding machine (Sumitomo Heavy Industries Co., Ltd., SE130DU-HP) Under the conditions of mold temperature 100°C and cylinder temperature 280°C, test pieces of 4mm×10mm×80mm were produced. The unnotched Sharpey impact strength was measured according to JIS K7111-1.

Example 2 <Synthesis of Resin B> In Example 1, the molar ratio of the cis-isomer/trans-isomer of 1,4-BAC was set to 40/60, and a polyamide resin was obtained in the same manner. The resulting polyamide resin is referred to as Resin B. <Various performance evaluations> In Example 1, the polyamide resin was changed to resin B, and the others were performed in the same manner.

Comparative Example 1 <Synthesis of Resin C> In Example 1, the molar ratio of the cis-isomer/trans-isomer of 1,4-BAC was set to 15/85, and a polyamide resin was obtained in the same manner. The obtained polyamide resin is called resin C. <Various performance evaluations> In Example 1, the polyamide resin was changed to resin C, and it performed in the same manner except that.

Comparative Example 2 <Synthesis of Resin D> In Example 1, the polyamide resin was obtained in the same manner as in Example 1, except that adipic acid was used instead of sebacic acid. The resulting polyamide resin is referred to as Resin D. <Various performance evaluations> In Example 1, the polyamide resin was changed to resin D, and it performed in the same manner except that.

Comparative Example 3 <Synthesis of Resin E> In Example 1, the molar ratio of sebacic acid, isophthalic acid, and terephthalic acid was 50:44:6, and the polyamide resin was obtained in the same manner. . The obtained polyamide resin is referred to as resin E. <Various performance evaluations> In Example 1, the polyamide resin was changed to resin E, and it performed in the same manner except that.

Comparative Example 4 <Synthesis of Resin F> In Example 1, an equimolar number of terephthalic acid was used instead of isophthalic acid. In addition, it was performed in the same manner, but it could not be synthesized.

Example 3 <Synthesis of Resin G> In Example 1, the molar ratio of the cis-isomer/trans-isomer of 1,4-BAC was set to 60/40, and the molar ratio of sebacic acid to isophthalic acid was 40:60, in addition, proceed in the same manner to obtain a polyamide resin. The resulting polyamide resin is referred to as Resin G. <Various performance evaluations> In Example 1, the polyamide resin was changed to resin G, and it performed in the same manner except that.

The results are shown in Table 1 below. 【Table 1】 In the above table, 1,4-BAC stands for 1,4-bis(aminomethyl)cyclohexane, SA stands for sebacic acid, AdA stands for adipic acid, PIA stands for isophthalic acid, PTA stands for terephthalic acid .

As is clear from the results, the polyamide resin of the present invention is excellent in heat aging resistance and has a high Sandpy impact strength (Examples 1 to 3). Furthermore, it is also known that the transparency is excellent (haze is low). In contrast, the polyamide resin (Comparative Example 1) obtained by using a trans molar ratio of more than 80 mol% for 1,4-bis(aminomethyl)cyclohexane had poor Sharpey impact strength. In addition, it can be seen that the constituent units derived from dicarboxylic acids are derived from polyamide resins (comparative example 2) derived from straight-chain aliphatic dicarboxylic acids with 7 or less carbon atoms and isophthalic acid and straight-chain fatty acids with 8 to 12 carbon atoms. The polyamide resin (Comparative Example 3) which contains structural units derived from terephthalic acid in addition to structural units of tricarboxylic dicarboxylic acid and isophthalic acid has poor heat aging resistance. It can be seen that the structural unit derived from dicarboxylic acid is a polyamide resin derived from linear aliphatic dicarboxylic acid having 8 to 12 carbon atoms and terephthalic acid (comparative example 4), which cannot be synthesized by this production method. Also, it can be seen that the resins of Examples 1 to 3 and Comparative Examples 1 to 3 have a crystal melting enthalpy ΔHm of almost 0 J/g in the heating process and are amorphous.

Claims (7)

A polyamide resin comprising a structural unit derived from diamine and a structural unit derived from dicarboxylic acid, and more than 98% by weight of the polyamide resin is the structural unit derived from dicarboxylic acid or the structural unit derived from diamine , more than 70 mol% of the constituent units derived from diamine are constituent units derived from 1,4-bis(aminomethyl)cyclohexane, and the 1,4-bis(amine constituting the constituent units derived from diamine In cyclohexane, the molar ratio of the cis-isomer to the trans-isomer (cis/trans) is 70/30~30/70, and the structural unit derived from dicarboxylic acid contains The constituent unit of formic acid and the constituent unit derived from straight-chain aliphatic dicarboxylic acid having 8 to 12 carbon atoms, and substantially no constituent unit derived from terephthalic acid, is amorphous. Such as the polyamide resin of item 1 of the scope of the patent application, wherein, 10-90 mol% of the constituent units derived from dicarboxylic acid are derived from isophthalic acid, and 90-10 mol% are derived from carbon number 8-12 straight-chain aliphatic dicarboxylic acids. For example, the polyamide resin of item 1 or 2 of the scope of the patent application, wherein the straight-chain aliphatic dicarboxylic acid with 8 to 12 carbon atoms is sebacic acid. Such as the polyamide resin of claim 1 or 2 of the patent scope, wherein the glass transition temperature of the polyamide resin is 100~190°C. Such as the polyamide resin of claim 1 or 2 of the patent scope, wherein the unnotched Charpy impact strength (Charpy impact strength) according to JIS K7111-1 is 150 kJ/m ² or more. Such as the polyamide resin of item 1 or 2 of the scope of the patent application, wherein the number average molecular weight of the polyamide resin is 8000~25000. A molded product is formed by molding a composition containing polyamide resin according to any one of items 1 to 6 of the patent application.